1290001Sglebius/* Copyright 2006-2007 Niels Provos 2290001Sglebius * Copyright 2007-2012 Nick Mathewson and Niels Provos 3290001Sglebius * 4290001Sglebius * Redistribution and use in source and binary forms, with or without 5290001Sglebius * modification, are permitted provided that the following conditions 6290001Sglebius * are met: 7290001Sglebius * 1. Redistributions of source code must retain the above copyright 8290001Sglebius * notice, this list of conditions and the following disclaimer. 9290001Sglebius * 2. Redistributions in binary form must reproduce the above copyright 10290001Sglebius * notice, this list of conditions and the following disclaimer in the 11290001Sglebius * documentation and/or other materials provided with the distribution. 12290001Sglebius * 3. The name of the author may not be used to endorse or promote products 13290001Sglebius * derived from this software without specific prior written permission. 14290001Sglebius * 15290001Sglebius * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16290001Sglebius * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17290001Sglebius * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18290001Sglebius * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19290001Sglebius * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20290001Sglebius * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21290001Sglebius * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22290001Sglebius * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23290001Sglebius * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24290001Sglebius * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25290001Sglebius */ 26290001Sglebius 27290001Sglebius/* Based on software by Adam Langly. Adam's original message: 28290001Sglebius * 29290001Sglebius * Async DNS Library 30290001Sglebius * Adam Langley <agl@imperialviolet.org> 31290001Sglebius * http://www.imperialviolet.org/eventdns.html 32290001Sglebius * Public Domain code 33290001Sglebius * 34290001Sglebius * This software is Public Domain. To view a copy of the public domain dedication, 35290001Sglebius * visit http://creativecommons.org/licenses/publicdomain/ or send a letter to 36290001Sglebius * Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA. 37290001Sglebius * 38290001Sglebius * I ask and expect, but do not require, that all derivative works contain an 39290001Sglebius * attribution similar to: 40290001Sglebius * Parts developed by Adam Langley <agl@imperialviolet.org> 41290001Sglebius * 42290001Sglebius * You may wish to replace the word "Parts" with something else depending on 43290001Sglebius * the amount of original code. 44290001Sglebius * 45290001Sglebius * (Derivative works does not include programs which link against, run or include 46290001Sglebius * the source verbatim in their source distributions) 47290001Sglebius * 48290001Sglebius * Version: 0.1b 49290001Sglebius */ 50290001Sglebius 51290001Sglebius#include "event2/event-config.h" 52290001Sglebius#include "evconfig-private.h" 53290001Sglebius 54290001Sglebius#include <sys/types.h> 55290001Sglebius 56290001Sglebius#ifndef _FORTIFY_SOURCE 57290001Sglebius#define _FORTIFY_SOURCE 3 58290001Sglebius#endif 59290001Sglebius 60290001Sglebius#include <string.h> 61290001Sglebius#include <fcntl.h> 62290001Sglebius#ifdef EVENT__HAVE_SYS_TIME_H 63290001Sglebius#include <sys/time.h> 64290001Sglebius#endif 65290001Sglebius#ifdef EVENT__HAVE_STDINT_H 66290001Sglebius#include <stdint.h> 67290001Sglebius#endif 68290001Sglebius#include <stdlib.h> 69290001Sglebius#include <string.h> 70290001Sglebius#include <errno.h> 71290001Sglebius#ifdef EVENT__HAVE_UNISTD_H 72290001Sglebius#include <unistd.h> 73290001Sglebius#endif 74290001Sglebius#include <limits.h> 75290001Sglebius#include <sys/stat.h> 76290001Sglebius#include <stdio.h> 77290001Sglebius#include <stdarg.h> 78290001Sglebius#ifdef _WIN32 79290001Sglebius#include <winsock2.h> 80290001Sglebius#include <ws2tcpip.h> 81290001Sglebius#ifndef _WIN32_IE 82290001Sglebius#define _WIN32_IE 0x400 83290001Sglebius#endif 84290001Sglebius#include <shlobj.h> 85290001Sglebius#endif 86290001Sglebius 87290001Sglebius#include "event2/dns.h" 88290001Sglebius#include "event2/dns_struct.h" 89290001Sglebius#include "event2/dns_compat.h" 90290001Sglebius#include "event2/util.h" 91290001Sglebius#include "event2/event.h" 92290001Sglebius#include "event2/event_struct.h" 93290001Sglebius#include "event2/thread.h" 94290001Sglebius 95290001Sglebius#include "defer-internal.h" 96290001Sglebius#include "log-internal.h" 97290001Sglebius#include "mm-internal.h" 98290001Sglebius#include "strlcpy-internal.h" 99290001Sglebius#include "ipv6-internal.h" 100290001Sglebius#include "util-internal.h" 101290001Sglebius#include "evthread-internal.h" 102290001Sglebius#ifdef _WIN32 103290001Sglebius#include <ctype.h> 104290001Sglebius#include <winsock2.h> 105290001Sglebius#include <windows.h> 106290001Sglebius#include <iphlpapi.h> 107290001Sglebius#include <io.h> 108290001Sglebius#else 109290001Sglebius#include <sys/socket.h> 110290001Sglebius#include <netinet/in.h> 111290001Sglebius#include <arpa/inet.h> 112290001Sglebius#endif 113290001Sglebius 114290001Sglebius#ifdef EVENT__HAVE_NETINET_IN6_H 115290001Sglebius#include <netinet/in6.h> 116290001Sglebius#endif 117290001Sglebius 118290001Sglebius#define EVDNS_LOG_DEBUG EVENT_LOG_DEBUG 119290001Sglebius#define EVDNS_LOG_WARN EVENT_LOG_WARN 120290001Sglebius#define EVDNS_LOG_MSG EVENT_LOG_MSG 121290001Sglebius 122290001Sglebius#ifndef HOST_NAME_MAX 123290001Sglebius#define HOST_NAME_MAX 255 124290001Sglebius#endif 125290001Sglebius 126290001Sglebius#include <stdio.h> 127290001Sglebius 128290001Sglebius#undef MIN 129290001Sglebius#define MIN(a,b) ((a)<(b)?(a):(b)) 130290001Sglebius 131290001Sglebius#define ASSERT_VALID_REQUEST(req) \ 132290001Sglebius EVUTIL_ASSERT((req)->handle && (req)->handle->current_req == (req)) 133290001Sglebius 134290001Sglebius#define u64 ev_uint64_t 135290001Sglebius#define u32 ev_uint32_t 136290001Sglebius#define u16 ev_uint16_t 137290001Sglebius#define u8 ev_uint8_t 138290001Sglebius 139290001Sglebius/* maximum number of addresses from a single packet */ 140290001Sglebius/* that we bother recording */ 141290001Sglebius#define MAX_V4_ADDRS 32 142290001Sglebius#define MAX_V6_ADDRS 32 143290001Sglebius 144290001Sglebius 145290001Sglebius#define TYPE_A EVDNS_TYPE_A 146290001Sglebius#define TYPE_CNAME 5 147290001Sglebius#define TYPE_PTR EVDNS_TYPE_PTR 148290001Sglebius#define TYPE_SOA EVDNS_TYPE_SOA 149290001Sglebius#define TYPE_AAAA EVDNS_TYPE_AAAA 150290001Sglebius 151290001Sglebius#define CLASS_INET EVDNS_CLASS_INET 152290001Sglebius 153290001Sglebius/* Persistent handle. We keep this separate from 'struct request' since we 154290001Sglebius * need some object to last for as long as an evdns_request is outstanding so 155290001Sglebius * that it can be canceled, whereas a search request can lead to multiple 156290001Sglebius * 'struct request' instances being created over its lifetime. */ 157290001Sglebiusstruct evdns_request { 158290001Sglebius struct request *current_req; 159290001Sglebius struct evdns_base *base; 160290001Sglebius 161290001Sglebius int pending_cb; /* Waiting for its callback to be invoked; not 162290001Sglebius * owned by event base any more. */ 163290001Sglebius 164290001Sglebius /* elements used by the searching code */ 165290001Sglebius int search_index; 166290001Sglebius struct search_state *search_state; 167290001Sglebius char *search_origname; /* needs to be free()ed */ 168290001Sglebius int search_flags; 169290001Sglebius}; 170290001Sglebius 171290001Sglebiusstruct request { 172290001Sglebius u8 *request; /* the dns packet data */ 173290001Sglebius u8 request_type; /* TYPE_PTR or TYPE_A or TYPE_AAAA */ 174290001Sglebius unsigned int request_len; 175290001Sglebius int reissue_count; 176290001Sglebius int tx_count; /* the number of times that this packet has been sent */ 177290001Sglebius void *user_pointer; /* the pointer given to us for this request */ 178290001Sglebius evdns_callback_type user_callback; 179290001Sglebius struct nameserver *ns; /* the server which we last sent it */ 180290001Sglebius 181290001Sglebius /* these objects are kept in a circular list */ 182290001Sglebius /* XXX We could turn this into a CIRCLEQ. */ 183290001Sglebius struct request *next, *prev; 184290001Sglebius 185290001Sglebius struct event timeout_event; 186290001Sglebius 187290001Sglebius u16 trans_id; /* the transaction id */ 188290001Sglebius unsigned request_appended :1; /* true if the request pointer is data which follows this struct */ 189290001Sglebius unsigned transmit_me :1; /* needs to be transmitted */ 190290001Sglebius 191290001Sglebius /* XXXX This is a horrible hack. */ 192290001Sglebius char **put_cname_in_ptr; /* store the cname here if we get one. */ 193290001Sglebius 194290001Sglebius struct evdns_base *base; 195290001Sglebius 196290001Sglebius struct evdns_request *handle; 197290001Sglebius}; 198290001Sglebius 199290001Sglebiusstruct reply { 200290001Sglebius unsigned int type; 201290001Sglebius unsigned int have_answer : 1; 202290001Sglebius union { 203290001Sglebius struct { 204290001Sglebius u32 addrcount; 205290001Sglebius u32 addresses[MAX_V4_ADDRS]; 206290001Sglebius } a; 207290001Sglebius struct { 208290001Sglebius u32 addrcount; 209290001Sglebius struct in6_addr addresses[MAX_V6_ADDRS]; 210290001Sglebius } aaaa; 211290001Sglebius struct { 212290001Sglebius char name[HOST_NAME_MAX]; 213290001Sglebius } ptr; 214290001Sglebius } data; 215290001Sglebius}; 216290001Sglebius 217290001Sglebiusstruct nameserver { 218290001Sglebius evutil_socket_t socket; /* a connected UDP socket */ 219290001Sglebius struct sockaddr_storage address; 220290001Sglebius ev_socklen_t addrlen; 221290001Sglebius int failed_times; /* number of times which we have given this server a chance */ 222290001Sglebius int timedout; /* number of times in a row a request has timed out */ 223290001Sglebius struct event event; 224290001Sglebius /* these objects are kept in a circular list */ 225290001Sglebius struct nameserver *next, *prev; 226290001Sglebius struct event timeout_event; /* used to keep the timeout for */ 227290001Sglebius /* when we next probe this server. */ 228290001Sglebius /* Valid if state == 0 */ 229290001Sglebius /* Outstanding probe request for this nameserver, if any */ 230290001Sglebius struct evdns_request *probe_request; 231290001Sglebius char state; /* zero if we think that this server is down */ 232290001Sglebius char choked; /* true if we have an EAGAIN from this server's socket */ 233290001Sglebius char write_waiting; /* true if we are waiting for EV_WRITE events */ 234290001Sglebius struct evdns_base *base; 235290001Sglebius 236290001Sglebius /* Number of currently inflight requests: used 237290001Sglebius * to track when we should add/del the event. */ 238290001Sglebius int requests_inflight; 239290001Sglebius}; 240290001Sglebius 241290001Sglebius 242290001Sglebius/* Represents a local port where we're listening for DNS requests. Right now, */ 243290001Sglebius/* only UDP is supported. */ 244290001Sglebiusstruct evdns_server_port { 245290001Sglebius evutil_socket_t socket; /* socket we use to read queries and write replies. */ 246290001Sglebius int refcnt; /* reference count. */ 247290001Sglebius char choked; /* Are we currently blocked from writing? */ 248290001Sglebius char closing; /* Are we trying to close this port, pending writes? */ 249290001Sglebius evdns_request_callback_fn_type user_callback; /* Fn to handle requests */ 250290001Sglebius void *user_data; /* Opaque pointer passed to user_callback */ 251290001Sglebius struct event event; /* Read/write event */ 252290001Sglebius /* circular list of replies that we want to write. */ 253290001Sglebius struct server_request *pending_replies; 254290001Sglebius struct event_base *event_base; 255290001Sglebius 256290001Sglebius#ifndef EVENT__DISABLE_THREAD_SUPPORT 257290001Sglebius void *lock; 258290001Sglebius#endif 259290001Sglebius}; 260290001Sglebius 261290001Sglebius/* Represents part of a reply being built. (That is, a single RR.) */ 262290001Sglebiusstruct server_reply_item { 263290001Sglebius struct server_reply_item *next; /* next item in sequence. */ 264290001Sglebius char *name; /* name part of the RR */ 265290001Sglebius u16 type; /* The RR type */ 266290001Sglebius u16 class; /* The RR class (usually CLASS_INET) */ 267290001Sglebius u32 ttl; /* The RR TTL */ 268290001Sglebius char is_name; /* True iff data is a label */ 269290001Sglebius u16 datalen; /* Length of data; -1 if data is a label */ 270290001Sglebius void *data; /* The contents of the RR */ 271290001Sglebius}; 272290001Sglebius 273290001Sglebius/* Represents a request that we've received as a DNS server, and holds */ 274290001Sglebius/* the components of the reply as we're constructing it. */ 275290001Sglebiusstruct server_request { 276290001Sglebius /* Pointers to the next and previous entries on the list of replies */ 277290001Sglebius /* that we're waiting to write. Only set if we have tried to respond */ 278290001Sglebius /* and gotten EAGAIN. */ 279290001Sglebius struct server_request *next_pending; 280290001Sglebius struct server_request *prev_pending; 281290001Sglebius 282290001Sglebius u16 trans_id; /* Transaction id. */ 283290001Sglebius struct evdns_server_port *port; /* Which port received this request on? */ 284290001Sglebius struct sockaddr_storage addr; /* Where to send the response */ 285290001Sglebius ev_socklen_t addrlen; /* length of addr */ 286290001Sglebius 287290001Sglebius int n_answer; /* how many answer RRs have been set? */ 288290001Sglebius int n_authority; /* how many authority RRs have been set? */ 289290001Sglebius int n_additional; /* how many additional RRs have been set? */ 290290001Sglebius 291290001Sglebius struct server_reply_item *answer; /* linked list of answer RRs */ 292290001Sglebius struct server_reply_item *authority; /* linked list of authority RRs */ 293290001Sglebius struct server_reply_item *additional; /* linked list of additional RRs */ 294290001Sglebius 295290001Sglebius /* Constructed response. Only set once we're ready to send a reply. */ 296290001Sglebius /* Once this is set, the RR fields are cleared, and no more should be set. */ 297290001Sglebius char *response; 298290001Sglebius size_t response_len; 299290001Sglebius 300290001Sglebius /* Caller-visible fields: flags, questions. */ 301290001Sglebius struct evdns_server_request base; 302290001Sglebius}; 303290001Sglebius 304290001Sglebiusstruct evdns_base { 305290001Sglebius /* An array of n_req_heads circular lists for inflight requests. 306290001Sglebius * Each inflight request req is in req_heads[req->trans_id % n_req_heads]. 307290001Sglebius */ 308290001Sglebius struct request **req_heads; 309290001Sglebius /* A circular list of requests that we're waiting to send, but haven't 310290001Sglebius * sent yet because there are too many requests inflight */ 311290001Sglebius struct request *req_waiting_head; 312290001Sglebius /* A circular list of nameservers. */ 313290001Sglebius struct nameserver *server_head; 314290001Sglebius int n_req_heads; 315290001Sglebius 316290001Sglebius struct event_base *event_base; 317290001Sglebius 318290001Sglebius /* The number of good nameservers that we have */ 319290001Sglebius int global_good_nameservers; 320290001Sglebius 321290001Sglebius /* inflight requests are contained in the req_head list */ 322290001Sglebius /* and are actually going out across the network */ 323290001Sglebius int global_requests_inflight; 324290001Sglebius /* requests which aren't inflight are in the waiting list */ 325290001Sglebius /* and are counted here */ 326290001Sglebius int global_requests_waiting; 327290001Sglebius 328290001Sglebius int global_max_requests_inflight; 329290001Sglebius 330290001Sglebius struct timeval global_timeout; /* 5 seconds by default */ 331290001Sglebius int global_max_reissues; /* a reissue occurs when we get some errors from the server */ 332290001Sglebius int global_max_retransmits; /* number of times we'll retransmit a request which timed out */ 333290001Sglebius /* number of timeouts in a row before we consider this server to be down */ 334290001Sglebius int global_max_nameserver_timeout; 335290001Sglebius /* true iff we will use the 0x20 hack to prevent poisoning attacks. */ 336290001Sglebius int global_randomize_case; 337290001Sglebius 338290001Sglebius /* The first time that a nameserver fails, how long do we wait before 339290001Sglebius * probing to see if it has returned? */ 340290001Sglebius struct timeval global_nameserver_probe_initial_timeout; 341290001Sglebius 342290001Sglebius /** Port to bind to for outgoing DNS packets. */ 343290001Sglebius struct sockaddr_storage global_outgoing_address; 344290001Sglebius /** ev_socklen_t for global_outgoing_address. 0 if it isn't set. */ 345290001Sglebius ev_socklen_t global_outgoing_addrlen; 346290001Sglebius 347290001Sglebius struct timeval global_getaddrinfo_allow_skew; 348290001Sglebius 349290001Sglebius int getaddrinfo_ipv4_timeouts; 350290001Sglebius int getaddrinfo_ipv6_timeouts; 351290001Sglebius int getaddrinfo_ipv4_answered; 352290001Sglebius int getaddrinfo_ipv6_answered; 353290001Sglebius 354290001Sglebius struct search_state *global_search_state; 355290001Sglebius 356290001Sglebius TAILQ_HEAD(hosts_list, hosts_entry) hostsdb; 357290001Sglebius 358290001Sglebius#ifndef EVENT__DISABLE_THREAD_SUPPORT 359290001Sglebius void *lock; 360290001Sglebius#endif 361290001Sglebius 362290001Sglebius int disable_when_inactive; 363290001Sglebius}; 364290001Sglebius 365290001Sglebiusstruct hosts_entry { 366290001Sglebius TAILQ_ENTRY(hosts_entry) next; 367290001Sglebius union { 368290001Sglebius struct sockaddr sa; 369290001Sglebius struct sockaddr_in sin; 370290001Sglebius struct sockaddr_in6 sin6; 371290001Sglebius } addr; 372290001Sglebius int addrlen; 373290001Sglebius char hostname[1]; 374290001Sglebius}; 375290001Sglebius 376290001Sglebiusstatic struct evdns_base *current_base = NULL; 377290001Sglebius 378290001Sglebiusstruct evdns_base * 379290001Sglebiusevdns_get_global_base(void) 380290001Sglebius{ 381290001Sglebius return current_base; 382290001Sglebius} 383290001Sglebius 384290001Sglebius/* Given a pointer to an evdns_server_request, get the corresponding */ 385290001Sglebius/* server_request. */ 386290001Sglebius#define TO_SERVER_REQUEST(base_ptr) \ 387290001Sglebius ((struct server_request*) \ 388290001Sglebius (((char*)(base_ptr) - evutil_offsetof(struct server_request, base)))) 389290001Sglebius 390290001Sglebius#define REQ_HEAD(base, id) ((base)->req_heads[id % (base)->n_req_heads]) 391290001Sglebius 392290001Sglebiusstatic struct nameserver *nameserver_pick(struct evdns_base *base); 393290001Sglebiusstatic void evdns_request_insert(struct request *req, struct request **head); 394290001Sglebiusstatic void evdns_request_remove(struct request *req, struct request **head); 395290001Sglebiusstatic void nameserver_ready_callback(evutil_socket_t fd, short events, void *arg); 396290001Sglebiusstatic int evdns_transmit(struct evdns_base *base); 397290001Sglebiusstatic int evdns_request_transmit(struct request *req); 398290001Sglebiusstatic void nameserver_send_probe(struct nameserver *const ns); 399290001Sglebiusstatic void search_request_finished(struct evdns_request *const); 400290001Sglebiusstatic int search_try_next(struct evdns_request *const req); 401290001Sglebiusstatic struct request *search_request_new(struct evdns_base *base, struct evdns_request *handle, int type, const char *const name, int flags, evdns_callback_type user_callback, void *user_arg); 402290001Sglebiusstatic void evdns_requests_pump_waiting_queue(struct evdns_base *base); 403290001Sglebiusstatic u16 transaction_id_pick(struct evdns_base *base); 404290001Sglebiusstatic struct request *request_new(struct evdns_base *base, struct evdns_request *handle, int type, const char *name, int flags, evdns_callback_type callback, void *ptr); 405290001Sglebiusstatic void request_submit(struct request *const req); 406290001Sglebius 407290001Sglebiusstatic int server_request_free(struct server_request *req); 408290001Sglebiusstatic void server_request_free_answers(struct server_request *req); 409290001Sglebiusstatic void server_port_free(struct evdns_server_port *port); 410290001Sglebiusstatic void server_port_ready_callback(evutil_socket_t fd, short events, void *arg); 411290001Sglebiusstatic int evdns_base_resolv_conf_parse_impl(struct evdns_base *base, int flags, const char *const filename); 412290001Sglebiusstatic int evdns_base_set_option_impl(struct evdns_base *base, 413290001Sglebius const char *option, const char *val, int flags); 414290001Sglebiusstatic void evdns_base_free_and_unlock(struct evdns_base *base, int fail_requests); 415290001Sglebiusstatic void evdns_request_timeout_callback(evutil_socket_t fd, short events, void *arg); 416290001Sglebius 417290001Sglebiusstatic int strtoint(const char *const str); 418290001Sglebius 419290001Sglebius#ifdef EVENT__DISABLE_THREAD_SUPPORT 420290001Sglebius#define EVDNS_LOCK(base) EVUTIL_NIL_STMT_ 421290001Sglebius#define EVDNS_UNLOCK(base) EVUTIL_NIL_STMT_ 422290001Sglebius#define ASSERT_LOCKED(base) EVUTIL_NIL_STMT_ 423290001Sglebius#else 424290001Sglebius#define EVDNS_LOCK(base) \ 425290001Sglebius EVLOCK_LOCK((base)->lock, 0) 426290001Sglebius#define EVDNS_UNLOCK(base) \ 427290001Sglebius EVLOCK_UNLOCK((base)->lock, 0) 428290001Sglebius#define ASSERT_LOCKED(base) \ 429290001Sglebius EVLOCK_ASSERT_LOCKED((base)->lock) 430290001Sglebius#endif 431290001Sglebius 432290001Sglebiusstatic evdns_debug_log_fn_type evdns_log_fn = NULL; 433290001Sglebius 434290001Sglebiusvoid 435290001Sglebiusevdns_set_log_fn(evdns_debug_log_fn_type fn) 436290001Sglebius{ 437290001Sglebius evdns_log_fn = fn; 438290001Sglebius} 439290001Sglebius 440290001Sglebius#ifdef __GNUC__ 441290001Sglebius#define EVDNS_LOG_CHECK __attribute__ ((format(printf, 2, 3))) 442290001Sglebius#else 443290001Sglebius#define EVDNS_LOG_CHECK 444290001Sglebius#endif 445290001Sglebius 446290001Sglebiusstatic void evdns_log_(int severity, const char *fmt, ...) EVDNS_LOG_CHECK; 447290001Sglebiusstatic void 448290001Sglebiusevdns_log_(int severity, const char *fmt, ...) 449290001Sglebius{ 450290001Sglebius va_list args; 451290001Sglebius va_start(args,fmt); 452290001Sglebius if (evdns_log_fn) { 453290001Sglebius char buf[512]; 454290001Sglebius int is_warn = (severity == EVDNS_LOG_WARN); 455290001Sglebius evutil_vsnprintf(buf, sizeof(buf), fmt, args); 456290001Sglebius evdns_log_fn(is_warn, buf); 457290001Sglebius } else { 458290001Sglebius event_logv_(severity, NULL, fmt, args); 459290001Sglebius } 460290001Sglebius va_end(args); 461290001Sglebius} 462290001Sglebius 463290001Sglebius#define log evdns_log_ 464290001Sglebius 465290001Sglebius/* This walks the list of inflight requests to find the */ 466290001Sglebius/* one with a matching transaction id. Returns NULL on */ 467290001Sglebius/* failure */ 468290001Sglebiusstatic struct request * 469290001Sglebiusrequest_find_from_trans_id(struct evdns_base *base, u16 trans_id) { 470290001Sglebius struct request *req = REQ_HEAD(base, trans_id); 471290001Sglebius struct request *const started_at = req; 472290001Sglebius 473290001Sglebius ASSERT_LOCKED(base); 474290001Sglebius 475290001Sglebius if (req) { 476290001Sglebius do { 477290001Sglebius if (req->trans_id == trans_id) return req; 478290001Sglebius req = req->next; 479290001Sglebius } while (req != started_at); 480290001Sglebius } 481290001Sglebius 482290001Sglebius return NULL; 483290001Sglebius} 484290001Sglebius 485290001Sglebius/* a libevent callback function which is called when a nameserver */ 486290001Sglebius/* has gone down and we want to test if it has came back to life yet */ 487290001Sglebiusstatic void 488290001Sglebiusnameserver_prod_callback(evutil_socket_t fd, short events, void *arg) { 489290001Sglebius struct nameserver *const ns = (struct nameserver *) arg; 490290001Sglebius (void)fd; 491290001Sglebius (void)events; 492290001Sglebius 493290001Sglebius EVDNS_LOCK(ns->base); 494290001Sglebius nameserver_send_probe(ns); 495290001Sglebius EVDNS_UNLOCK(ns->base); 496290001Sglebius} 497290001Sglebius 498290001Sglebius/* a libevent callback which is called when a nameserver probe (to see if */ 499290001Sglebius/* it has come back to life) times out. We increment the count of failed_times */ 500290001Sglebius/* and wait longer to send the next probe packet. */ 501290001Sglebiusstatic void 502290001Sglebiusnameserver_probe_failed(struct nameserver *const ns) { 503290001Sglebius struct timeval timeout; 504290001Sglebius int i; 505290001Sglebius 506290001Sglebius ASSERT_LOCKED(ns->base); 507290001Sglebius (void) evtimer_del(&ns->timeout_event); 508290001Sglebius if (ns->state == 1) { 509290001Sglebius /* This can happen if the nameserver acts in a way which makes us mark */ 510290001Sglebius /* it as bad and then starts sending good replies. */ 511290001Sglebius return; 512290001Sglebius } 513290001Sglebius 514290001Sglebius#define MAX_PROBE_TIMEOUT 3600 515290001Sglebius#define TIMEOUT_BACKOFF_FACTOR 3 516290001Sglebius 517290001Sglebius memcpy(&timeout, &ns->base->global_nameserver_probe_initial_timeout, 518290001Sglebius sizeof(struct timeval)); 519290001Sglebius for (i=ns->failed_times; i > 0 && timeout.tv_sec < MAX_PROBE_TIMEOUT; --i) { 520290001Sglebius timeout.tv_sec *= TIMEOUT_BACKOFF_FACTOR; 521290001Sglebius timeout.tv_usec *= TIMEOUT_BACKOFF_FACTOR; 522290001Sglebius if (timeout.tv_usec > 1000000) { 523290001Sglebius timeout.tv_sec += timeout.tv_usec / 1000000; 524290001Sglebius timeout.tv_usec %= 1000000; 525290001Sglebius } 526290001Sglebius } 527290001Sglebius if (timeout.tv_sec > MAX_PROBE_TIMEOUT) { 528290001Sglebius timeout.tv_sec = MAX_PROBE_TIMEOUT; 529290001Sglebius timeout.tv_usec = 0; 530290001Sglebius } 531290001Sglebius 532290001Sglebius ns->failed_times++; 533290001Sglebius 534290001Sglebius if (evtimer_add(&ns->timeout_event, &timeout) < 0) { 535290001Sglebius char addrbuf[128]; 536290001Sglebius log(EVDNS_LOG_WARN, 537290001Sglebius "Error from libevent when adding timer event for %s", 538290001Sglebius evutil_format_sockaddr_port_( 539290001Sglebius (struct sockaddr *)&ns->address, 540290001Sglebius addrbuf, sizeof(addrbuf))); 541290001Sglebius } 542290001Sglebius} 543290001Sglebius 544290001Sglebiusstatic void 545290001Sglebiusrequest_swap_ns(struct request *req, struct nameserver *ns) { 546290001Sglebius if (ns && req->ns != ns) { 547290001Sglebius EVUTIL_ASSERT(req->ns->requests_inflight > 0); 548290001Sglebius req->ns->requests_inflight--; 549290001Sglebius ns->requests_inflight++; 550290001Sglebius 551290001Sglebius req->ns = ns; 552290001Sglebius } 553290001Sglebius} 554290001Sglebius 555290001Sglebius/* called when a nameserver has been deemed to have failed. For example, too */ 556290001Sglebius/* many packets have timed out etc */ 557290001Sglebiusstatic void 558290001Sglebiusnameserver_failed(struct nameserver *const ns, const char *msg) { 559290001Sglebius struct request *req, *started_at; 560290001Sglebius struct evdns_base *base = ns->base; 561290001Sglebius int i; 562290001Sglebius char addrbuf[128]; 563290001Sglebius 564290001Sglebius ASSERT_LOCKED(base); 565290001Sglebius /* if this nameserver has already been marked as failed */ 566290001Sglebius /* then don't do anything */ 567290001Sglebius if (!ns->state) return; 568290001Sglebius 569290001Sglebius log(EVDNS_LOG_MSG, "Nameserver %s has failed: %s", 570290001Sglebius evutil_format_sockaddr_port_( 571290001Sglebius (struct sockaddr *)&ns->address, 572290001Sglebius addrbuf, sizeof(addrbuf)), 573290001Sglebius msg); 574290001Sglebius 575290001Sglebius base->global_good_nameservers--; 576290001Sglebius EVUTIL_ASSERT(base->global_good_nameservers >= 0); 577290001Sglebius if (base->global_good_nameservers == 0) { 578290001Sglebius log(EVDNS_LOG_MSG, "All nameservers have failed"); 579290001Sglebius } 580290001Sglebius 581290001Sglebius ns->state = 0; 582290001Sglebius ns->failed_times = 1; 583290001Sglebius 584290001Sglebius if (evtimer_add(&ns->timeout_event, 585290001Sglebius &base->global_nameserver_probe_initial_timeout) < 0) { 586290001Sglebius log(EVDNS_LOG_WARN, 587290001Sglebius "Error from libevent when adding timer event for %s", 588290001Sglebius evutil_format_sockaddr_port_( 589290001Sglebius (struct sockaddr *)&ns->address, 590290001Sglebius addrbuf, sizeof(addrbuf))); 591290001Sglebius /* ???? Do more? */ 592290001Sglebius } 593290001Sglebius 594290001Sglebius /* walk the list of inflight requests to see if any can be reassigned to */ 595290001Sglebius /* a different server. Requests in the waiting queue don't have a */ 596290001Sglebius /* nameserver assigned yet */ 597290001Sglebius 598290001Sglebius /* if we don't have *any* good nameservers then there's no point */ 599290001Sglebius /* trying to reassign requests to one */ 600290001Sglebius if (!base->global_good_nameservers) return; 601290001Sglebius 602290001Sglebius for (i = 0; i < base->n_req_heads; ++i) { 603290001Sglebius req = started_at = base->req_heads[i]; 604290001Sglebius if (req) { 605290001Sglebius do { 606290001Sglebius if (req->tx_count == 0 && req->ns == ns) { 607290001Sglebius /* still waiting to go out, can be moved */ 608290001Sglebius /* to another server */ 609290001Sglebius request_swap_ns(req, nameserver_pick(base)); 610290001Sglebius } 611290001Sglebius req = req->next; 612290001Sglebius } while (req != started_at); 613290001Sglebius } 614290001Sglebius } 615290001Sglebius} 616290001Sglebius 617290001Sglebiusstatic void 618290001Sglebiusnameserver_up(struct nameserver *const ns) 619290001Sglebius{ 620290001Sglebius char addrbuf[128]; 621290001Sglebius ASSERT_LOCKED(ns->base); 622290001Sglebius if (ns->state) return; 623290001Sglebius log(EVDNS_LOG_MSG, "Nameserver %s is back up", 624290001Sglebius evutil_format_sockaddr_port_( 625290001Sglebius (struct sockaddr *)&ns->address, 626290001Sglebius addrbuf, sizeof(addrbuf))); 627290001Sglebius evtimer_del(&ns->timeout_event); 628290001Sglebius if (ns->probe_request) { 629290001Sglebius evdns_cancel_request(ns->base, ns->probe_request); 630290001Sglebius ns->probe_request = NULL; 631290001Sglebius } 632290001Sglebius ns->state = 1; 633290001Sglebius ns->failed_times = 0; 634290001Sglebius ns->timedout = 0; 635290001Sglebius ns->base->global_good_nameservers++; 636290001Sglebius} 637290001Sglebius 638290001Sglebiusstatic void 639290001Sglebiusrequest_trans_id_set(struct request *const req, const u16 trans_id) { 640290001Sglebius req->trans_id = trans_id; 641290001Sglebius *((u16 *) req->request) = htons(trans_id); 642290001Sglebius} 643290001Sglebius 644290001Sglebius/* Called to remove a request from a list and dealloc it. */ 645290001Sglebius/* head is a pointer to the head of the list it should be */ 646290001Sglebius/* removed from or NULL if the request isn't in a list. */ 647290001Sglebius/* when free_handle is one, free the handle as well. */ 648290001Sglebiusstatic void 649290001Sglebiusrequest_finished(struct request *const req, struct request **head, int free_handle) { 650290001Sglebius struct evdns_base *base = req->base; 651290001Sglebius int was_inflight = (head != &base->req_waiting_head); 652290001Sglebius EVDNS_LOCK(base); 653290001Sglebius ASSERT_VALID_REQUEST(req); 654290001Sglebius 655290001Sglebius if (head) 656290001Sglebius evdns_request_remove(req, head); 657290001Sglebius 658290001Sglebius log(EVDNS_LOG_DEBUG, "Removing timeout for request %p", req); 659290001Sglebius if (was_inflight) { 660290001Sglebius evtimer_del(&req->timeout_event); 661290001Sglebius base->global_requests_inflight--; 662290001Sglebius req->ns->requests_inflight--; 663290001Sglebius } else { 664290001Sglebius base->global_requests_waiting--; 665290001Sglebius } 666290001Sglebius /* it was initialized during request_new / evtimer_assign */ 667290001Sglebius event_debug_unassign(&req->timeout_event); 668290001Sglebius 669290001Sglebius if (req->ns && 670290001Sglebius req->ns->requests_inflight == 0 && 671290001Sglebius req->base->disable_when_inactive) { 672290001Sglebius event_del(&req->ns->event); 673290001Sglebius evtimer_del(&req->ns->timeout_event); 674290001Sglebius } 675290001Sglebius 676290001Sglebius if (!req->request_appended) { 677290001Sglebius /* need to free the request data on it's own */ 678290001Sglebius mm_free(req->request); 679290001Sglebius } else { 680290001Sglebius /* the request data is appended onto the header */ 681290001Sglebius /* so everything gets free()ed when we: */ 682290001Sglebius } 683290001Sglebius 684290001Sglebius if (req->handle) { 685290001Sglebius EVUTIL_ASSERT(req->handle->current_req == req); 686290001Sglebius 687290001Sglebius if (free_handle) { 688290001Sglebius search_request_finished(req->handle); 689290001Sglebius req->handle->current_req = NULL; 690290001Sglebius if (! req->handle->pending_cb) { 691290001Sglebius /* If we're planning to run the callback, 692290001Sglebius * don't free the handle until later. */ 693290001Sglebius mm_free(req->handle); 694290001Sglebius } 695290001Sglebius req->handle = NULL; /* If we have a bug, let's crash 696290001Sglebius * early */ 697290001Sglebius } else { 698290001Sglebius req->handle->current_req = NULL; 699290001Sglebius } 700290001Sglebius } 701290001Sglebius 702290001Sglebius mm_free(req); 703290001Sglebius 704290001Sglebius evdns_requests_pump_waiting_queue(base); 705290001Sglebius EVDNS_UNLOCK(base); 706290001Sglebius} 707290001Sglebius 708290001Sglebius/* This is called when a server returns a funny error code. */ 709290001Sglebius/* We try the request again with another server. */ 710290001Sglebius/* */ 711290001Sglebius/* return: */ 712290001Sglebius/* 0 ok */ 713290001Sglebius/* 1 failed/reissue is pointless */ 714290001Sglebiusstatic int 715290001Sglebiusrequest_reissue(struct request *req) { 716290001Sglebius const struct nameserver *const last_ns = req->ns; 717290001Sglebius ASSERT_LOCKED(req->base); 718290001Sglebius ASSERT_VALID_REQUEST(req); 719290001Sglebius /* the last nameserver should have been marked as failing */ 720290001Sglebius /* by the caller of this function, therefore pick will try */ 721290001Sglebius /* not to return it */ 722290001Sglebius request_swap_ns(req, nameserver_pick(req->base)); 723290001Sglebius if (req->ns == last_ns) { 724290001Sglebius /* ... but pick did return it */ 725290001Sglebius /* not a lot of point in trying again with the */ 726290001Sglebius /* same server */ 727290001Sglebius return 1; 728290001Sglebius } 729290001Sglebius 730290001Sglebius req->reissue_count++; 731290001Sglebius req->tx_count = 0; 732290001Sglebius req->transmit_me = 1; 733290001Sglebius 734290001Sglebius return 0; 735290001Sglebius} 736290001Sglebius 737290001Sglebius/* this function looks for space on the inflight queue and promotes */ 738290001Sglebius/* requests from the waiting queue if it can. */ 739290001Sglebius/* */ 740290001Sglebius/* TODO: */ 741290001Sglebius/* add return code, see at nameserver_pick() and other functions. */ 742290001Sglebiusstatic void 743290001Sglebiusevdns_requests_pump_waiting_queue(struct evdns_base *base) { 744290001Sglebius ASSERT_LOCKED(base); 745290001Sglebius while (base->global_requests_inflight < base->global_max_requests_inflight && 746290001Sglebius base->global_requests_waiting) { 747290001Sglebius struct request *req; 748290001Sglebius 749290001Sglebius EVUTIL_ASSERT(base->req_waiting_head); 750290001Sglebius req = base->req_waiting_head; 751290001Sglebius 752290001Sglebius req->ns = nameserver_pick(base); 753290001Sglebius if (!req->ns) 754290001Sglebius return; 755290001Sglebius 756290001Sglebius /* move a request from the waiting queue to the inflight queue */ 757290001Sglebius req->ns->requests_inflight++; 758290001Sglebius 759290001Sglebius evdns_request_remove(req, &base->req_waiting_head); 760290001Sglebius 761290001Sglebius base->global_requests_waiting--; 762290001Sglebius base->global_requests_inflight++; 763290001Sglebius 764290001Sglebius request_trans_id_set(req, transaction_id_pick(base)); 765290001Sglebius 766290001Sglebius evdns_request_insert(req, &REQ_HEAD(base, req->trans_id)); 767290001Sglebius evdns_request_transmit(req); 768290001Sglebius evdns_transmit(base); 769290001Sglebius } 770290001Sglebius} 771290001Sglebius 772290001Sglebius/* TODO(nickm) document */ 773290001Sglebiusstruct deferred_reply_callback { 774290001Sglebius struct event_callback deferred; 775290001Sglebius struct evdns_request *handle; 776290001Sglebius u8 request_type; 777290001Sglebius u8 have_reply; 778290001Sglebius u32 ttl; 779290001Sglebius u32 err; 780290001Sglebius evdns_callback_type user_callback; 781290001Sglebius struct reply reply; 782290001Sglebius}; 783290001Sglebius 784290001Sglebiusstatic void 785290001Sglebiusreply_run_callback(struct event_callback *d, void *user_pointer) 786290001Sglebius{ 787290001Sglebius struct deferred_reply_callback *cb = 788290001Sglebius EVUTIL_UPCAST(d, struct deferred_reply_callback, deferred); 789290001Sglebius 790290001Sglebius switch (cb->request_type) { 791290001Sglebius case TYPE_A: 792290001Sglebius if (cb->have_reply) 793290001Sglebius cb->user_callback(DNS_ERR_NONE, DNS_IPv4_A, 794290001Sglebius cb->reply.data.a.addrcount, cb->ttl, 795290001Sglebius cb->reply.data.a.addresses, 796290001Sglebius user_pointer); 797290001Sglebius else 798290001Sglebius cb->user_callback(cb->err, 0, 0, cb->ttl, NULL, user_pointer); 799290001Sglebius break; 800290001Sglebius case TYPE_PTR: 801290001Sglebius if (cb->have_reply) { 802290001Sglebius char *name = cb->reply.data.ptr.name; 803290001Sglebius cb->user_callback(DNS_ERR_NONE, DNS_PTR, 1, cb->ttl, 804290001Sglebius &name, user_pointer); 805290001Sglebius } else { 806290001Sglebius cb->user_callback(cb->err, 0, 0, cb->ttl, NULL, user_pointer); 807290001Sglebius } 808290001Sglebius break; 809290001Sglebius case TYPE_AAAA: 810290001Sglebius if (cb->have_reply) 811290001Sglebius cb->user_callback(DNS_ERR_NONE, DNS_IPv6_AAAA, 812290001Sglebius cb->reply.data.aaaa.addrcount, cb->ttl, 813290001Sglebius cb->reply.data.aaaa.addresses, 814290001Sglebius user_pointer); 815290001Sglebius else 816290001Sglebius cb->user_callback(cb->err, 0, 0, cb->ttl, NULL, user_pointer); 817290001Sglebius break; 818290001Sglebius default: 819290001Sglebius EVUTIL_ASSERT(0); 820290001Sglebius } 821290001Sglebius 822290001Sglebius if (cb->handle && cb->handle->pending_cb) { 823290001Sglebius mm_free(cb->handle); 824290001Sglebius } 825290001Sglebius 826290001Sglebius mm_free(cb); 827290001Sglebius} 828290001Sglebius 829290001Sglebiusstatic void 830290001Sglebiusreply_schedule_callback(struct request *const req, u32 ttl, u32 err, struct reply *reply) 831290001Sglebius{ 832290001Sglebius struct deferred_reply_callback *d = mm_calloc(1, sizeof(*d)); 833290001Sglebius 834290001Sglebius if (!d) { 835290001Sglebius event_warn("%s: Couldn't allocate space for deferred callback.", 836290001Sglebius __func__); 837290001Sglebius return; 838290001Sglebius } 839290001Sglebius 840290001Sglebius ASSERT_LOCKED(req->base); 841290001Sglebius 842290001Sglebius d->request_type = req->request_type; 843290001Sglebius d->user_callback = req->user_callback; 844290001Sglebius d->ttl = ttl; 845290001Sglebius d->err = err; 846290001Sglebius if (reply) { 847290001Sglebius d->have_reply = 1; 848290001Sglebius memcpy(&d->reply, reply, sizeof(struct reply)); 849290001Sglebius } 850290001Sglebius 851290001Sglebius if (req->handle) { 852290001Sglebius req->handle->pending_cb = 1; 853290001Sglebius d->handle = req->handle; 854290001Sglebius } 855290001Sglebius 856290001Sglebius event_deferred_cb_init_( 857290001Sglebius &d->deferred, 858290001Sglebius event_get_priority(&req->timeout_event), 859290001Sglebius reply_run_callback, 860290001Sglebius req->user_pointer); 861290001Sglebius event_deferred_cb_schedule_( 862290001Sglebius req->base->event_base, 863290001Sglebius &d->deferred); 864290001Sglebius} 865290001Sglebius 866290001Sglebius/* this processes a parsed reply packet */ 867290001Sglebiusstatic void 868290001Sglebiusreply_handle(struct request *const req, u16 flags, u32 ttl, struct reply *reply) { 869290001Sglebius int error; 870290001Sglebius char addrbuf[128]; 871290001Sglebius static const int error_codes[] = { 872290001Sglebius DNS_ERR_FORMAT, DNS_ERR_SERVERFAILED, DNS_ERR_NOTEXIST, 873290001Sglebius DNS_ERR_NOTIMPL, DNS_ERR_REFUSED 874290001Sglebius }; 875290001Sglebius 876290001Sglebius ASSERT_LOCKED(req->base); 877290001Sglebius ASSERT_VALID_REQUEST(req); 878290001Sglebius 879290001Sglebius if (flags & 0x020f || !reply || !reply->have_answer) { 880290001Sglebius /* there was an error */ 881290001Sglebius if (flags & 0x0200) { 882290001Sglebius error = DNS_ERR_TRUNCATED; 883290001Sglebius } else if (flags & 0x000f) { 884290001Sglebius u16 error_code = (flags & 0x000f) - 1; 885290001Sglebius if (error_code > 4) { 886290001Sglebius error = DNS_ERR_UNKNOWN; 887290001Sglebius } else { 888290001Sglebius error = error_codes[error_code]; 889290001Sglebius } 890290001Sglebius } else if (reply && !reply->have_answer) { 891290001Sglebius error = DNS_ERR_NODATA; 892290001Sglebius } else { 893290001Sglebius error = DNS_ERR_UNKNOWN; 894290001Sglebius } 895290001Sglebius 896290001Sglebius switch (error) { 897290001Sglebius case DNS_ERR_NOTIMPL: 898290001Sglebius case DNS_ERR_REFUSED: 899290001Sglebius /* we regard these errors as marking a bad nameserver */ 900290001Sglebius if (req->reissue_count < req->base->global_max_reissues) { 901290001Sglebius char msg[64]; 902290001Sglebius evutil_snprintf(msg, sizeof(msg), "Bad response %d (%s)", 903290001Sglebius error, evdns_err_to_string(error)); 904290001Sglebius nameserver_failed(req->ns, msg); 905290001Sglebius if (!request_reissue(req)) return; 906290001Sglebius } 907290001Sglebius break; 908290001Sglebius case DNS_ERR_SERVERFAILED: 909290001Sglebius /* rcode 2 (servfailed) sometimes means "we 910290001Sglebius * are broken" and sometimes (with some binds) 911290001Sglebius * means "that request was very confusing." 912290001Sglebius * Treat this as a timeout, not a failure. 913290001Sglebius */ 914290001Sglebius log(EVDNS_LOG_DEBUG, "Got a SERVERFAILED from nameserver" 915290001Sglebius "at %s; will allow the request to time out.", 916290001Sglebius evutil_format_sockaddr_port_( 917290001Sglebius (struct sockaddr *)&req->ns->address, 918290001Sglebius addrbuf, sizeof(addrbuf))); 919290001Sglebius /* Call the timeout function */ 920290001Sglebius evdns_request_timeout_callback(0, 0, req); 921290001Sglebius return; 922290001Sglebius default: 923290001Sglebius /* we got a good reply from the nameserver: it is up. */ 924290001Sglebius if (req->handle == req->ns->probe_request) { 925290001Sglebius /* Avoid double-free */ 926290001Sglebius req->ns->probe_request = NULL; 927290001Sglebius } 928290001Sglebius 929290001Sglebius nameserver_up(req->ns); 930290001Sglebius } 931290001Sglebius 932290001Sglebius if (req->handle->search_state && 933290001Sglebius req->request_type != TYPE_PTR) { 934290001Sglebius /* if we have a list of domains to search in, 935290001Sglebius * try the next one */ 936290001Sglebius if (!search_try_next(req->handle)) { 937290001Sglebius /* a new request was issued so this 938290001Sglebius * request is finished and */ 939290001Sglebius /* the user callback will be made when 940290001Sglebius * that request (or a */ 941290001Sglebius /* child of it) finishes. */ 942290001Sglebius return; 943290001Sglebius } 944290001Sglebius } 945290001Sglebius 946290001Sglebius /* all else failed. Pass the failure up */ 947290001Sglebius reply_schedule_callback(req, ttl, error, NULL); 948290001Sglebius request_finished(req, &REQ_HEAD(req->base, req->trans_id), 1); 949290001Sglebius } else { 950290001Sglebius /* all ok, tell the user */ 951290001Sglebius reply_schedule_callback(req, ttl, 0, reply); 952290001Sglebius if (req->handle == req->ns->probe_request) 953290001Sglebius req->ns->probe_request = NULL; /* Avoid double-free */ 954290001Sglebius nameserver_up(req->ns); 955290001Sglebius request_finished(req, &REQ_HEAD(req->base, req->trans_id), 1); 956290001Sglebius } 957290001Sglebius} 958290001Sglebius 959290001Sglebiusstatic int 960290001Sglebiusname_parse(u8 *packet, int length, int *idx, char *name_out, int name_out_len) { 961290001Sglebius int name_end = -1; 962290001Sglebius int j = *idx; 963290001Sglebius int ptr_count = 0; 964290001Sglebius#define GET32(x) do { if (j + 4 > length) goto err; memcpy(&t32_, packet + j, 4); j += 4; x = ntohl(t32_); } while (0) 965290001Sglebius#define GET16(x) do { if (j + 2 > length) goto err; memcpy(&t_, packet + j, 2); j += 2; x = ntohs(t_); } while (0) 966290001Sglebius#define GET8(x) do { if (j >= length) goto err; x = packet[j++]; } while (0) 967290001Sglebius 968290001Sglebius char *cp = name_out; 969290001Sglebius const char *const end = name_out + name_out_len; 970290001Sglebius 971290001Sglebius /* Normally, names are a series of length prefixed strings terminated */ 972290001Sglebius /* with a length of 0 (the lengths are u8's < 63). */ 973290001Sglebius /* However, the length can start with a pair of 1 bits and that */ 974290001Sglebius /* means that the next 14 bits are a pointer within the current */ 975290001Sglebius /* packet. */ 976290001Sglebius 977290001Sglebius for (;;) { 978290001Sglebius u8 label_len; 979290001Sglebius if (j >= length) return -1; 980290001Sglebius GET8(label_len); 981290001Sglebius if (!label_len) break; 982290001Sglebius if (label_len & 0xc0) { 983290001Sglebius u8 ptr_low; 984290001Sglebius GET8(ptr_low); 985290001Sglebius if (name_end < 0) name_end = j; 986290001Sglebius j = (((int)label_len & 0x3f) << 8) + ptr_low; 987290001Sglebius /* Make sure that the target offset is in-bounds. */ 988290001Sglebius if (j < 0 || j >= length) return -1; 989290001Sglebius /* If we've jumped more times than there are characters in the 990290001Sglebius * message, we must have a loop. */ 991290001Sglebius if (++ptr_count > length) return -1; 992290001Sglebius continue; 993290001Sglebius } 994290001Sglebius if (label_len > 63) return -1; 995290001Sglebius if (cp != name_out) { 996290001Sglebius if (cp + 1 >= end) return -1; 997290001Sglebius *cp++ = '.'; 998290001Sglebius } 999290001Sglebius if (cp + label_len >= end) return -1; 1000290001Sglebius memcpy(cp, packet + j, label_len); 1001290001Sglebius cp += label_len; 1002290001Sglebius j += label_len; 1003290001Sglebius } 1004290001Sglebius if (cp >= end) return -1; 1005290001Sglebius *cp = '\0'; 1006290001Sglebius if (name_end < 0) 1007290001Sglebius *idx = j; 1008290001Sglebius else 1009290001Sglebius *idx = name_end; 1010290001Sglebius return 0; 1011290001Sglebius err: 1012290001Sglebius return -1; 1013290001Sglebius} 1014290001Sglebius 1015290001Sglebius/* parses a raw request from a nameserver */ 1016290001Sglebiusstatic int 1017290001Sglebiusreply_parse(struct evdns_base *base, u8 *packet, int length) { 1018290001Sglebius int j = 0, k = 0; /* index into packet */ 1019290001Sglebius u16 t_; /* used by the macros */ 1020290001Sglebius u32 t32_; /* used by the macros */ 1021290001Sglebius char tmp_name[256], cmp_name[256]; /* used by the macros */ 1022290001Sglebius int name_matches = 0; 1023290001Sglebius 1024290001Sglebius u16 trans_id, questions, answers, authority, additional, datalength; 1025290001Sglebius u16 flags = 0; 1026290001Sglebius u32 ttl, ttl_r = 0xffffffff; 1027290001Sglebius struct reply reply; 1028290001Sglebius struct request *req = NULL; 1029290001Sglebius unsigned int i; 1030290001Sglebius 1031290001Sglebius ASSERT_LOCKED(base); 1032290001Sglebius 1033290001Sglebius GET16(trans_id); 1034290001Sglebius GET16(flags); 1035290001Sglebius GET16(questions); 1036290001Sglebius GET16(answers); 1037290001Sglebius GET16(authority); 1038290001Sglebius GET16(additional); 1039290001Sglebius (void) authority; /* suppress "unused variable" warnings. */ 1040290001Sglebius (void) additional; /* suppress "unused variable" warnings. */ 1041290001Sglebius 1042290001Sglebius req = request_find_from_trans_id(base, trans_id); 1043290001Sglebius if (!req) return -1; 1044290001Sglebius EVUTIL_ASSERT(req->base == base); 1045290001Sglebius 1046290001Sglebius memset(&reply, 0, sizeof(reply)); 1047290001Sglebius 1048290001Sglebius /* If it's not an answer, it doesn't correspond to any request. */ 1049290001Sglebius if (!(flags & 0x8000)) return -1; /* must be an answer */ 1050290001Sglebius if ((flags & 0x020f) && (flags & 0x020f) != DNS_ERR_NOTEXIST) { 1051290001Sglebius /* there was an error and it's not NXDOMAIN */ 1052290001Sglebius goto err; 1053290001Sglebius } 1054290001Sglebius /* if (!answers) return; */ /* must have an answer of some form */ 1055290001Sglebius 1056290001Sglebius /* This macro skips a name in the DNS reply. */ 1057290001Sglebius#define SKIP_NAME \ 1058290001Sglebius do { tmp_name[0] = '\0'; \ 1059290001Sglebius if (name_parse(packet, length, &j, tmp_name, \ 1060290001Sglebius sizeof(tmp_name))<0) \ 1061290001Sglebius goto err; \ 1062290001Sglebius } while (0) 1063290001Sglebius#define TEST_NAME \ 1064290001Sglebius do { tmp_name[0] = '\0'; \ 1065290001Sglebius cmp_name[0] = '\0'; \ 1066290001Sglebius k = j; \ 1067290001Sglebius if (name_parse(packet, length, &j, tmp_name, \ 1068290001Sglebius sizeof(tmp_name))<0) \ 1069290001Sglebius goto err; \ 1070290001Sglebius if (name_parse(req->request, req->request_len, &k, \ 1071290001Sglebius cmp_name, sizeof(cmp_name))<0) \ 1072290001Sglebius goto err; \ 1073290001Sglebius if (base->global_randomize_case) { \ 1074290001Sglebius if (strcmp(tmp_name, cmp_name) == 0) \ 1075290001Sglebius name_matches = 1; \ 1076290001Sglebius } else { \ 1077290001Sglebius if (evutil_ascii_strcasecmp(tmp_name, cmp_name) == 0) \ 1078290001Sglebius name_matches = 1; \ 1079290001Sglebius } \ 1080290001Sglebius } while (0) 1081290001Sglebius 1082290001Sglebius reply.type = req->request_type; 1083290001Sglebius 1084290001Sglebius /* skip over each question in the reply */ 1085290001Sglebius for (i = 0; i < questions; ++i) { 1086290001Sglebius /* the question looks like 1087290001Sglebius * <label:name><u16:type><u16:class> 1088290001Sglebius */ 1089290001Sglebius TEST_NAME; 1090290001Sglebius j += 4; 1091290001Sglebius if (j > length) goto err; 1092290001Sglebius } 1093290001Sglebius 1094290001Sglebius if (!name_matches) 1095290001Sglebius goto err; 1096290001Sglebius 1097290001Sglebius /* now we have the answer section which looks like 1098290001Sglebius * <label:name><u16:type><u16:class><u32:ttl><u16:len><data...> 1099290001Sglebius */ 1100290001Sglebius 1101290001Sglebius for (i = 0; i < answers; ++i) { 1102290001Sglebius u16 type, class; 1103290001Sglebius 1104290001Sglebius SKIP_NAME; 1105290001Sglebius GET16(type); 1106290001Sglebius GET16(class); 1107290001Sglebius GET32(ttl); 1108290001Sglebius GET16(datalength); 1109290001Sglebius 1110290001Sglebius if (type == TYPE_A && class == CLASS_INET) { 1111290001Sglebius int addrcount, addrtocopy; 1112290001Sglebius if (req->request_type != TYPE_A) { 1113290001Sglebius j += datalength; continue; 1114290001Sglebius } 1115290001Sglebius if ((datalength & 3) != 0) /* not an even number of As. */ 1116290001Sglebius goto err; 1117290001Sglebius addrcount = datalength >> 2; 1118290001Sglebius addrtocopy = MIN(MAX_V4_ADDRS - reply.data.a.addrcount, (unsigned)addrcount); 1119290001Sglebius 1120290001Sglebius ttl_r = MIN(ttl_r, ttl); 1121290001Sglebius /* we only bother with the first four addresses. */ 1122290001Sglebius if (j + 4*addrtocopy > length) goto err; 1123290001Sglebius memcpy(&reply.data.a.addresses[reply.data.a.addrcount], 1124290001Sglebius packet + j, 4*addrtocopy); 1125290001Sglebius j += 4*addrtocopy; 1126290001Sglebius reply.data.a.addrcount += addrtocopy; 1127290001Sglebius reply.have_answer = 1; 1128290001Sglebius if (reply.data.a.addrcount == MAX_V4_ADDRS) break; 1129290001Sglebius } else if (type == TYPE_PTR && class == CLASS_INET) { 1130290001Sglebius if (req->request_type != TYPE_PTR) { 1131290001Sglebius j += datalength; continue; 1132290001Sglebius } 1133290001Sglebius if (name_parse(packet, length, &j, reply.data.ptr.name, 1134290001Sglebius sizeof(reply.data.ptr.name))<0) 1135290001Sglebius goto err; 1136290001Sglebius ttl_r = MIN(ttl_r, ttl); 1137290001Sglebius reply.have_answer = 1; 1138290001Sglebius break; 1139290001Sglebius } else if (type == TYPE_CNAME) { 1140290001Sglebius char cname[HOST_NAME_MAX]; 1141290001Sglebius if (!req->put_cname_in_ptr || *req->put_cname_in_ptr) { 1142290001Sglebius j += datalength; continue; 1143290001Sglebius } 1144290001Sglebius if (name_parse(packet, length, &j, cname, 1145290001Sglebius sizeof(cname))<0) 1146290001Sglebius goto err; 1147290001Sglebius *req->put_cname_in_ptr = mm_strdup(cname); 1148290001Sglebius } else if (type == TYPE_AAAA && class == CLASS_INET) { 1149290001Sglebius int addrcount, addrtocopy; 1150290001Sglebius if (req->request_type != TYPE_AAAA) { 1151290001Sglebius j += datalength; continue; 1152290001Sglebius } 1153290001Sglebius if ((datalength & 15) != 0) /* not an even number of AAAAs. */ 1154290001Sglebius goto err; 1155290001Sglebius addrcount = datalength >> 4; /* each address is 16 bytes long */ 1156290001Sglebius addrtocopy = MIN(MAX_V6_ADDRS - reply.data.aaaa.addrcount, (unsigned)addrcount); 1157290001Sglebius ttl_r = MIN(ttl_r, ttl); 1158290001Sglebius 1159290001Sglebius /* we only bother with the first four addresses. */ 1160290001Sglebius if (j + 16*addrtocopy > length) goto err; 1161290001Sglebius memcpy(&reply.data.aaaa.addresses[reply.data.aaaa.addrcount], 1162290001Sglebius packet + j, 16*addrtocopy); 1163290001Sglebius reply.data.aaaa.addrcount += addrtocopy; 1164290001Sglebius j += 16*addrtocopy; 1165290001Sglebius reply.have_answer = 1; 1166290001Sglebius if (reply.data.aaaa.addrcount == MAX_V6_ADDRS) break; 1167290001Sglebius } else { 1168290001Sglebius /* skip over any other type of resource */ 1169290001Sglebius j += datalength; 1170290001Sglebius } 1171290001Sglebius } 1172290001Sglebius 1173290001Sglebius if (!reply.have_answer) { 1174290001Sglebius for (i = 0; i < authority; ++i) { 1175290001Sglebius u16 type, class; 1176290001Sglebius SKIP_NAME; 1177290001Sglebius GET16(type); 1178290001Sglebius GET16(class); 1179290001Sglebius GET32(ttl); 1180290001Sglebius GET16(datalength); 1181290001Sglebius if (type == TYPE_SOA && class == CLASS_INET) { 1182290001Sglebius u32 serial, refresh, retry, expire, minimum; 1183290001Sglebius SKIP_NAME; 1184290001Sglebius SKIP_NAME; 1185290001Sglebius GET32(serial); 1186290001Sglebius GET32(refresh); 1187290001Sglebius GET32(retry); 1188290001Sglebius GET32(expire); 1189290001Sglebius GET32(minimum); 1190290001Sglebius (void)expire; 1191290001Sglebius (void)retry; 1192290001Sglebius (void)refresh; 1193290001Sglebius (void)serial; 1194290001Sglebius ttl_r = MIN(ttl_r, ttl); 1195290001Sglebius ttl_r = MIN(ttl_r, minimum); 1196290001Sglebius } else { 1197290001Sglebius /* skip over any other type of resource */ 1198290001Sglebius j += datalength; 1199290001Sglebius } 1200290001Sglebius } 1201290001Sglebius } 1202290001Sglebius 1203290001Sglebius if (ttl_r == 0xffffffff) 1204290001Sglebius ttl_r = 0; 1205290001Sglebius 1206290001Sglebius reply_handle(req, flags, ttl_r, &reply); 1207290001Sglebius return 0; 1208290001Sglebius err: 1209290001Sglebius if (req) 1210290001Sglebius reply_handle(req, flags, 0, NULL); 1211290001Sglebius return -1; 1212290001Sglebius} 1213290001Sglebius 1214290001Sglebius/* Parse a raw request (packet,length) sent to a nameserver port (port) from */ 1215290001Sglebius/* a DNS client (addr,addrlen), and if it's well-formed, call the corresponding */ 1216290001Sglebius/* callback. */ 1217290001Sglebiusstatic int 1218290001Sglebiusrequest_parse(u8 *packet, int length, struct evdns_server_port *port, struct sockaddr *addr, ev_socklen_t addrlen) 1219290001Sglebius{ 1220290001Sglebius int j = 0; /* index into packet */ 1221290001Sglebius u16 t_; /* used by the macros */ 1222290001Sglebius char tmp_name[256]; /* used by the macros */ 1223290001Sglebius 1224290001Sglebius int i; 1225290001Sglebius u16 trans_id, flags, questions, answers, authority, additional; 1226290001Sglebius struct server_request *server_req = NULL; 1227290001Sglebius 1228290001Sglebius ASSERT_LOCKED(port); 1229290001Sglebius 1230290001Sglebius /* Get the header fields */ 1231290001Sglebius GET16(trans_id); 1232290001Sglebius GET16(flags); 1233290001Sglebius GET16(questions); 1234290001Sglebius GET16(answers); 1235290001Sglebius GET16(authority); 1236290001Sglebius GET16(additional); 1237290001Sglebius (void)answers; 1238290001Sglebius (void)additional; 1239290001Sglebius (void)authority; 1240290001Sglebius 1241290001Sglebius if (flags & 0x8000) return -1; /* Must not be an answer. */ 1242290001Sglebius flags &= 0x0110; /* Only RD and CD get preserved. */ 1243290001Sglebius 1244290001Sglebius server_req = mm_malloc(sizeof(struct server_request)); 1245290001Sglebius if (server_req == NULL) return -1; 1246290001Sglebius memset(server_req, 0, sizeof(struct server_request)); 1247290001Sglebius 1248290001Sglebius server_req->trans_id = trans_id; 1249290001Sglebius memcpy(&server_req->addr, addr, addrlen); 1250290001Sglebius server_req->addrlen = addrlen; 1251290001Sglebius 1252290001Sglebius server_req->base.flags = flags; 1253290001Sglebius server_req->base.nquestions = 0; 1254290001Sglebius server_req->base.questions = mm_calloc(sizeof(struct evdns_server_question *), questions); 1255290001Sglebius if (server_req->base.questions == NULL) 1256290001Sglebius goto err; 1257290001Sglebius 1258290001Sglebius for (i = 0; i < questions; ++i) { 1259290001Sglebius u16 type, class; 1260290001Sglebius struct evdns_server_question *q; 1261290001Sglebius int namelen; 1262290001Sglebius if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0) 1263290001Sglebius goto err; 1264290001Sglebius GET16(type); 1265290001Sglebius GET16(class); 1266290001Sglebius namelen = (int)strlen(tmp_name); 1267290001Sglebius q = mm_malloc(sizeof(struct evdns_server_question) + namelen); 1268290001Sglebius if (!q) 1269290001Sglebius goto err; 1270290001Sglebius q->type = type; 1271290001Sglebius q->dns_question_class = class; 1272290001Sglebius memcpy(q->name, tmp_name, namelen+1); 1273290001Sglebius server_req->base.questions[server_req->base.nquestions++] = q; 1274290001Sglebius } 1275290001Sglebius 1276290001Sglebius /* Ignore answers, authority, and additional. */ 1277290001Sglebius 1278290001Sglebius server_req->port = port; 1279290001Sglebius port->refcnt++; 1280290001Sglebius 1281290001Sglebius /* Only standard queries are supported. */ 1282290001Sglebius if (flags & 0x7800) { 1283290001Sglebius evdns_server_request_respond(&(server_req->base), DNS_ERR_NOTIMPL); 1284290001Sglebius return -1; 1285290001Sglebius } 1286290001Sglebius 1287290001Sglebius port->user_callback(&(server_req->base), port->user_data); 1288290001Sglebius 1289290001Sglebius return 0; 1290290001Sglebiuserr: 1291290001Sglebius if (server_req) { 1292290001Sglebius if (server_req->base.questions) { 1293290001Sglebius for (i = 0; i < server_req->base.nquestions; ++i) 1294290001Sglebius mm_free(server_req->base.questions[i]); 1295290001Sglebius mm_free(server_req->base.questions); 1296290001Sglebius } 1297290001Sglebius mm_free(server_req); 1298290001Sglebius } 1299290001Sglebius return -1; 1300290001Sglebius 1301290001Sglebius#undef SKIP_NAME 1302290001Sglebius#undef GET32 1303290001Sglebius#undef GET16 1304290001Sglebius#undef GET8 1305290001Sglebius} 1306290001Sglebius 1307290001Sglebius 1308290001Sglebiusvoid 1309290001Sglebiusevdns_set_transaction_id_fn(ev_uint16_t (*fn)(void)) 1310290001Sglebius{ 1311290001Sglebius} 1312290001Sglebius 1313290001Sglebiusvoid 1314290001Sglebiusevdns_set_random_bytes_fn(void (*fn)(char *, size_t)) 1315290001Sglebius{ 1316290001Sglebius} 1317290001Sglebius 1318290001Sglebius/* Try to choose a strong transaction id which isn't already in flight */ 1319290001Sglebiusstatic u16 1320290001Sglebiustransaction_id_pick(struct evdns_base *base) { 1321290001Sglebius ASSERT_LOCKED(base); 1322290001Sglebius for (;;) { 1323290001Sglebius u16 trans_id; 1324290001Sglebius evutil_secure_rng_get_bytes(&trans_id, sizeof(trans_id)); 1325290001Sglebius 1326290001Sglebius if (trans_id == 0xffff) continue; 1327290001Sglebius /* now check to see if that id is already inflight */ 1328290001Sglebius if (request_find_from_trans_id(base, trans_id) == NULL) 1329290001Sglebius return trans_id; 1330290001Sglebius } 1331290001Sglebius} 1332290001Sglebius 1333290001Sglebius/* choose a namesever to use. This function will try to ignore */ 1334290001Sglebius/* nameservers which we think are down and load balance across the rest */ 1335290001Sglebius/* by updating the server_head global each time. */ 1336290001Sglebiusstatic struct nameserver * 1337290001Sglebiusnameserver_pick(struct evdns_base *base) { 1338290001Sglebius struct nameserver *started_at = base->server_head, *picked; 1339290001Sglebius ASSERT_LOCKED(base); 1340290001Sglebius if (!base->server_head) return NULL; 1341290001Sglebius 1342290001Sglebius /* if we don't have any good nameservers then there's no */ 1343290001Sglebius /* point in trying to find one. */ 1344290001Sglebius if (!base->global_good_nameservers) { 1345290001Sglebius base->server_head = base->server_head->next; 1346290001Sglebius return base->server_head; 1347290001Sglebius } 1348290001Sglebius 1349290001Sglebius /* remember that nameservers are in a circular list */ 1350290001Sglebius for (;;) { 1351290001Sglebius if (base->server_head->state) { 1352290001Sglebius /* we think this server is currently good */ 1353290001Sglebius picked = base->server_head; 1354290001Sglebius base->server_head = base->server_head->next; 1355290001Sglebius return picked; 1356290001Sglebius } 1357290001Sglebius 1358290001Sglebius base->server_head = base->server_head->next; 1359290001Sglebius if (base->server_head == started_at) { 1360290001Sglebius /* all the nameservers seem to be down */ 1361290001Sglebius /* so we just return this one and hope for the */ 1362290001Sglebius /* best */ 1363290001Sglebius EVUTIL_ASSERT(base->global_good_nameservers == 0); 1364290001Sglebius picked = base->server_head; 1365290001Sglebius base->server_head = base->server_head->next; 1366290001Sglebius return picked; 1367290001Sglebius } 1368290001Sglebius } 1369290001Sglebius} 1370290001Sglebius 1371290001Sglebius/* this is called when a namesever socket is ready for reading */ 1372290001Sglebiusstatic void 1373290001Sglebiusnameserver_read(struct nameserver *ns) { 1374290001Sglebius struct sockaddr_storage ss; 1375290001Sglebius ev_socklen_t addrlen = sizeof(ss); 1376290001Sglebius u8 packet[1500]; 1377290001Sglebius char addrbuf[128]; 1378290001Sglebius ASSERT_LOCKED(ns->base); 1379290001Sglebius 1380290001Sglebius for (;;) { 1381290001Sglebius const int r = recvfrom(ns->socket, (void*)packet, 1382290001Sglebius sizeof(packet), 0, 1383290001Sglebius (struct sockaddr*)&ss, &addrlen); 1384290001Sglebius if (r < 0) { 1385290001Sglebius int err = evutil_socket_geterror(ns->socket); 1386290001Sglebius if (EVUTIL_ERR_RW_RETRIABLE(err)) 1387290001Sglebius return; 1388290001Sglebius nameserver_failed(ns, 1389290001Sglebius evutil_socket_error_to_string(err)); 1390290001Sglebius return; 1391290001Sglebius } 1392290001Sglebius if (evutil_sockaddr_cmp((struct sockaddr*)&ss, 1393290001Sglebius (struct sockaddr*)&ns->address, 0)) { 1394290001Sglebius log(EVDNS_LOG_WARN, "Address mismatch on received " 1395290001Sglebius "DNS packet. Apparent source was %s", 1396290001Sglebius evutil_format_sockaddr_port_( 1397290001Sglebius (struct sockaddr *)&ss, 1398290001Sglebius addrbuf, sizeof(addrbuf))); 1399290001Sglebius return; 1400290001Sglebius } 1401290001Sglebius 1402290001Sglebius ns->timedout = 0; 1403290001Sglebius reply_parse(ns->base, packet, r); 1404290001Sglebius } 1405290001Sglebius} 1406290001Sglebius 1407290001Sglebius/* Read a packet from a DNS client on a server port s, parse it, and */ 1408290001Sglebius/* act accordingly. */ 1409290001Sglebiusstatic void 1410290001Sglebiusserver_port_read(struct evdns_server_port *s) { 1411290001Sglebius u8 packet[1500]; 1412290001Sglebius struct sockaddr_storage addr; 1413290001Sglebius ev_socklen_t addrlen; 1414290001Sglebius int r; 1415290001Sglebius ASSERT_LOCKED(s); 1416290001Sglebius 1417290001Sglebius for (;;) { 1418290001Sglebius addrlen = sizeof(struct sockaddr_storage); 1419290001Sglebius r = recvfrom(s->socket, (void*)packet, sizeof(packet), 0, 1420290001Sglebius (struct sockaddr*) &addr, &addrlen); 1421290001Sglebius if (r < 0) { 1422290001Sglebius int err = evutil_socket_geterror(s->socket); 1423290001Sglebius if (EVUTIL_ERR_RW_RETRIABLE(err)) 1424290001Sglebius return; 1425290001Sglebius log(EVDNS_LOG_WARN, 1426290001Sglebius "Error %s (%d) while reading request.", 1427290001Sglebius evutil_socket_error_to_string(err), err); 1428290001Sglebius return; 1429290001Sglebius } 1430290001Sglebius request_parse(packet, r, s, (struct sockaddr*) &addr, addrlen); 1431290001Sglebius } 1432290001Sglebius} 1433290001Sglebius 1434290001Sglebius/* Try to write all pending replies on a given DNS server port. */ 1435290001Sglebiusstatic void 1436290001Sglebiusserver_port_flush(struct evdns_server_port *port) 1437290001Sglebius{ 1438290001Sglebius struct server_request *req = port->pending_replies; 1439290001Sglebius ASSERT_LOCKED(port); 1440290001Sglebius while (req) { 1441290001Sglebius int r = sendto(port->socket, req->response, (int)req->response_len, 0, 1442290001Sglebius (struct sockaddr*) &req->addr, (ev_socklen_t)req->addrlen); 1443290001Sglebius if (r < 0) { 1444290001Sglebius int err = evutil_socket_geterror(port->socket); 1445290001Sglebius if (EVUTIL_ERR_RW_RETRIABLE(err)) 1446290001Sglebius return; 1447290001Sglebius log(EVDNS_LOG_WARN, "Error %s (%d) while writing response to port; dropping", evutil_socket_error_to_string(err), err); 1448290001Sglebius } 1449290001Sglebius if (server_request_free(req)) { 1450290001Sglebius /* we released the last reference to req->port. */ 1451290001Sglebius return; 1452290001Sglebius } else { 1453290001Sglebius EVUTIL_ASSERT(req != port->pending_replies); 1454290001Sglebius req = port->pending_replies; 1455290001Sglebius } 1456290001Sglebius } 1457290001Sglebius 1458290001Sglebius /* We have no more pending requests; stop listening for 'writeable' events. */ 1459290001Sglebius (void) event_del(&port->event); 1460290001Sglebius event_assign(&port->event, port->event_base, 1461290001Sglebius port->socket, EV_READ | EV_PERSIST, 1462290001Sglebius server_port_ready_callback, port); 1463290001Sglebius 1464290001Sglebius if (event_add(&port->event, NULL) < 0) { 1465290001Sglebius log(EVDNS_LOG_WARN, "Error from libevent when adding event for DNS server."); 1466290001Sglebius /* ???? Do more? */ 1467290001Sglebius } 1468290001Sglebius} 1469290001Sglebius 1470290001Sglebius/* set if we are waiting for the ability to write to this server. */ 1471290001Sglebius/* if waiting is true then we ask libevent for EV_WRITE events, otherwise */ 1472290001Sglebius/* we stop these events. */ 1473290001Sglebiusstatic void 1474290001Sglebiusnameserver_write_waiting(struct nameserver *ns, char waiting) { 1475290001Sglebius ASSERT_LOCKED(ns->base); 1476290001Sglebius if (ns->write_waiting == waiting) return; 1477290001Sglebius 1478290001Sglebius ns->write_waiting = waiting; 1479290001Sglebius (void) event_del(&ns->event); 1480290001Sglebius event_assign(&ns->event, ns->base->event_base, 1481290001Sglebius ns->socket, EV_READ | (waiting ? EV_WRITE : 0) | EV_PERSIST, 1482290001Sglebius nameserver_ready_callback, ns); 1483290001Sglebius if (event_add(&ns->event, NULL) < 0) { 1484290001Sglebius char addrbuf[128]; 1485290001Sglebius log(EVDNS_LOG_WARN, "Error from libevent when adding event for %s", 1486290001Sglebius evutil_format_sockaddr_port_( 1487290001Sglebius (struct sockaddr *)&ns->address, 1488290001Sglebius addrbuf, sizeof(addrbuf))); 1489290001Sglebius /* ???? Do more? */ 1490290001Sglebius } 1491290001Sglebius} 1492290001Sglebius 1493290001Sglebius/* a callback function. Called by libevent when the kernel says that */ 1494290001Sglebius/* a nameserver socket is ready for writing or reading */ 1495290001Sglebiusstatic void 1496290001Sglebiusnameserver_ready_callback(evutil_socket_t fd, short events, void *arg) { 1497290001Sglebius struct nameserver *ns = (struct nameserver *) arg; 1498290001Sglebius (void)fd; 1499290001Sglebius 1500290001Sglebius EVDNS_LOCK(ns->base); 1501290001Sglebius if (events & EV_WRITE) { 1502290001Sglebius ns->choked = 0; 1503290001Sglebius if (!evdns_transmit(ns->base)) { 1504290001Sglebius nameserver_write_waiting(ns, 0); 1505290001Sglebius } 1506290001Sglebius } 1507290001Sglebius if (events & EV_READ) { 1508290001Sglebius nameserver_read(ns); 1509290001Sglebius } 1510290001Sglebius EVDNS_UNLOCK(ns->base); 1511290001Sglebius} 1512290001Sglebius 1513290001Sglebius/* a callback function. Called by libevent when the kernel says that */ 1514290001Sglebius/* a server socket is ready for writing or reading. */ 1515290001Sglebiusstatic void 1516290001Sglebiusserver_port_ready_callback(evutil_socket_t fd, short events, void *arg) { 1517290001Sglebius struct evdns_server_port *port = (struct evdns_server_port *) arg; 1518290001Sglebius (void) fd; 1519290001Sglebius 1520290001Sglebius EVDNS_LOCK(port); 1521290001Sglebius if (events & EV_WRITE) { 1522290001Sglebius port->choked = 0; 1523290001Sglebius server_port_flush(port); 1524290001Sglebius } 1525290001Sglebius if (events & EV_READ) { 1526290001Sglebius server_port_read(port); 1527290001Sglebius } 1528290001Sglebius EVDNS_UNLOCK(port); 1529290001Sglebius} 1530290001Sglebius 1531290001Sglebius/* This is an inefficient representation; only use it via the dnslabel_table_* 1532290001Sglebius * functions, so that is can be safely replaced with something smarter later. */ 1533290001Sglebius#define MAX_LABELS 128 1534290001Sglebius/* Structures used to implement name compression */ 1535290001Sglebiusstruct dnslabel_entry { char *v; off_t pos; }; 1536290001Sglebiusstruct dnslabel_table { 1537290001Sglebius int n_labels; /* number of current entries */ 1538290001Sglebius /* map from name to position in message */ 1539290001Sglebius struct dnslabel_entry labels[MAX_LABELS]; 1540290001Sglebius}; 1541290001Sglebius 1542290001Sglebius/* Initialize dnslabel_table. */ 1543290001Sglebiusstatic void 1544290001Sglebiusdnslabel_table_init(struct dnslabel_table *table) 1545290001Sglebius{ 1546290001Sglebius table->n_labels = 0; 1547290001Sglebius} 1548290001Sglebius 1549290001Sglebius/* Free all storage held by table, but not the table itself. */ 1550290001Sglebiusstatic void 1551290001Sglebiusdnslabel_clear(struct dnslabel_table *table) 1552290001Sglebius{ 1553290001Sglebius int i; 1554290001Sglebius for (i = 0; i < table->n_labels; ++i) 1555290001Sglebius mm_free(table->labels[i].v); 1556290001Sglebius table->n_labels = 0; 1557290001Sglebius} 1558290001Sglebius 1559290001Sglebius/* return the position of the label in the current message, or -1 if the label */ 1560290001Sglebius/* hasn't been used yet. */ 1561290001Sglebiusstatic int 1562290001Sglebiusdnslabel_table_get_pos(const struct dnslabel_table *table, const char *label) 1563290001Sglebius{ 1564290001Sglebius int i; 1565290001Sglebius for (i = 0; i < table->n_labels; ++i) { 1566290001Sglebius if (!strcmp(label, table->labels[i].v)) 1567290001Sglebius return table->labels[i].pos; 1568290001Sglebius } 1569290001Sglebius return -1; 1570290001Sglebius} 1571290001Sglebius 1572290001Sglebius/* remember that we've used the label at position pos */ 1573290001Sglebiusstatic int 1574290001Sglebiusdnslabel_table_add(struct dnslabel_table *table, const char *label, off_t pos) 1575290001Sglebius{ 1576290001Sglebius char *v; 1577290001Sglebius int p; 1578290001Sglebius if (table->n_labels == MAX_LABELS) 1579290001Sglebius return (-1); 1580290001Sglebius v = mm_strdup(label); 1581290001Sglebius if (v == NULL) 1582290001Sglebius return (-1); 1583290001Sglebius p = table->n_labels++; 1584290001Sglebius table->labels[p].v = v; 1585290001Sglebius table->labels[p].pos = pos; 1586290001Sglebius 1587290001Sglebius return (0); 1588290001Sglebius} 1589290001Sglebius 1590290001Sglebius/* Converts a string to a length-prefixed set of DNS labels, starting */ 1591290001Sglebius/* at buf[j]. name and buf must not overlap. name_len should be the length */ 1592290001Sglebius/* of name. table is optional, and is used for compression. */ 1593290001Sglebius/* */ 1594290001Sglebius/* Input: abc.def */ 1595290001Sglebius/* Output: <3>abc<3>def<0> */ 1596290001Sglebius/* */ 1597290001Sglebius/* Returns the first index after the encoded name, or negative on error. */ 1598290001Sglebius/* -1 label was > 63 bytes */ 1599290001Sglebius/* -2 name too long to fit in buffer. */ 1600290001Sglebius/* */ 1601290001Sglebiusstatic off_t 1602290001Sglebiusdnsname_to_labels(u8 *const buf, size_t buf_len, off_t j, 1603290001Sglebius const char *name, const size_t name_len, 1604290001Sglebius struct dnslabel_table *table) { 1605290001Sglebius const char *end = name + name_len; 1606290001Sglebius int ref = 0; 1607290001Sglebius u16 t_; 1608290001Sglebius 1609290001Sglebius#define APPEND16(x) do { \ 1610290001Sglebius if (j + 2 > (off_t)buf_len) \ 1611290001Sglebius goto overflow; \ 1612290001Sglebius t_ = htons(x); \ 1613290001Sglebius memcpy(buf + j, &t_, 2); \ 1614290001Sglebius j += 2; \ 1615290001Sglebius } while (0) 1616290001Sglebius#define APPEND32(x) do { \ 1617290001Sglebius if (j + 4 > (off_t)buf_len) \ 1618290001Sglebius goto overflow; \ 1619290001Sglebius t32_ = htonl(x); \ 1620290001Sglebius memcpy(buf + j, &t32_, 4); \ 1621290001Sglebius j += 4; \ 1622290001Sglebius } while (0) 1623290001Sglebius 1624290001Sglebius if (name_len > 255) return -2; 1625290001Sglebius 1626290001Sglebius for (;;) { 1627290001Sglebius const char *const start = name; 1628290001Sglebius if (table && (ref = dnslabel_table_get_pos(table, name)) >= 0) { 1629290001Sglebius APPEND16(ref | 0xc000); 1630290001Sglebius return j; 1631290001Sglebius } 1632290001Sglebius name = strchr(name, '.'); 1633290001Sglebius if (!name) { 1634290001Sglebius const size_t label_len = end - start; 1635290001Sglebius if (label_len > 63) return -1; 1636290001Sglebius if ((size_t)(j+label_len+1) > buf_len) return -2; 1637290001Sglebius if (table) dnslabel_table_add(table, start, j); 1638290001Sglebius buf[j++] = (ev_uint8_t)label_len; 1639290001Sglebius 1640290001Sglebius memcpy(buf + j, start, label_len); 1641290001Sglebius j += (int) label_len; 1642290001Sglebius break; 1643290001Sglebius } else { 1644290001Sglebius /* append length of the label. */ 1645290001Sglebius const size_t label_len = name - start; 1646290001Sglebius if (label_len > 63) return -1; 1647290001Sglebius if ((size_t)(j+label_len+1) > buf_len) return -2; 1648290001Sglebius if (table) dnslabel_table_add(table, start, j); 1649290001Sglebius buf[j++] = (ev_uint8_t)label_len; 1650290001Sglebius 1651290001Sglebius memcpy(buf + j, start, label_len); 1652290001Sglebius j += (int) label_len; 1653290001Sglebius /* hop over the '.' */ 1654290001Sglebius name++; 1655290001Sglebius } 1656290001Sglebius } 1657290001Sglebius 1658290001Sglebius /* the labels must be terminated by a 0. */ 1659290001Sglebius /* It's possible that the name ended in a . */ 1660290001Sglebius /* in which case the zero is already there */ 1661290001Sglebius if (!j || buf[j-1]) buf[j++] = 0; 1662290001Sglebius return j; 1663290001Sglebius overflow: 1664290001Sglebius return (-2); 1665290001Sglebius} 1666290001Sglebius 1667290001Sglebius/* Finds the length of a dns request for a DNS name of the given */ 1668290001Sglebius/* length. The actual request may be smaller than the value returned */ 1669290001Sglebius/* here */ 1670290001Sglebiusstatic size_t 1671290001Sglebiusevdns_request_len(const size_t name_len) { 1672290001Sglebius return 96 + /* length of the DNS standard header */ 1673290001Sglebius name_len + 2 + 1674290001Sglebius 4; /* space for the resource type */ 1675290001Sglebius} 1676290001Sglebius 1677290001Sglebius/* build a dns request packet into buf. buf should be at least as long */ 1678290001Sglebius/* as evdns_request_len told you it should be. */ 1679290001Sglebius/* */ 1680290001Sglebius/* Returns the amount of space used. Negative on error. */ 1681290001Sglebiusstatic int 1682290001Sglebiusevdns_request_data_build(const char *const name, const size_t name_len, 1683290001Sglebius const u16 trans_id, const u16 type, const u16 class, 1684290001Sglebius u8 *const buf, size_t buf_len) { 1685290001Sglebius off_t j = 0; /* current offset into buf */ 1686290001Sglebius u16 t_; /* used by the macros */ 1687290001Sglebius 1688290001Sglebius APPEND16(trans_id); 1689290001Sglebius APPEND16(0x0100); /* standard query, recusion needed */ 1690290001Sglebius APPEND16(1); /* one question */ 1691290001Sglebius APPEND16(0); /* no answers */ 1692290001Sglebius APPEND16(0); /* no authority */ 1693290001Sglebius APPEND16(0); /* no additional */ 1694290001Sglebius 1695290001Sglebius j = dnsname_to_labels(buf, buf_len, j, name, name_len, NULL); 1696290001Sglebius if (j < 0) { 1697290001Sglebius return (int)j; 1698290001Sglebius } 1699290001Sglebius 1700290001Sglebius APPEND16(type); 1701290001Sglebius APPEND16(class); 1702290001Sglebius 1703290001Sglebius return (int)j; 1704290001Sglebius overflow: 1705290001Sglebius return (-1); 1706290001Sglebius} 1707290001Sglebius 1708290001Sglebius/* exported function */ 1709290001Sglebiusstruct evdns_server_port * 1710290001Sglebiusevdns_add_server_port_with_base(struct event_base *base, evutil_socket_t socket, int flags, evdns_request_callback_fn_type cb, void *user_data) 1711290001Sglebius{ 1712290001Sglebius struct evdns_server_port *port; 1713290001Sglebius if (flags) 1714290001Sglebius return NULL; /* flags not yet implemented */ 1715290001Sglebius if (!(port = mm_malloc(sizeof(struct evdns_server_port)))) 1716290001Sglebius return NULL; 1717290001Sglebius memset(port, 0, sizeof(struct evdns_server_port)); 1718290001Sglebius 1719290001Sglebius 1720290001Sglebius port->socket = socket; 1721290001Sglebius port->refcnt = 1; 1722290001Sglebius port->choked = 0; 1723290001Sglebius port->closing = 0; 1724290001Sglebius port->user_callback = cb; 1725290001Sglebius port->user_data = user_data; 1726290001Sglebius port->pending_replies = NULL; 1727290001Sglebius port->event_base = base; 1728290001Sglebius 1729290001Sglebius event_assign(&port->event, port->event_base, 1730290001Sglebius port->socket, EV_READ | EV_PERSIST, 1731290001Sglebius server_port_ready_callback, port); 1732290001Sglebius if (event_add(&port->event, NULL) < 0) { 1733290001Sglebius mm_free(port); 1734290001Sglebius return NULL; 1735290001Sglebius } 1736290001Sglebius EVTHREAD_ALLOC_LOCK(port->lock, EVTHREAD_LOCKTYPE_RECURSIVE); 1737290001Sglebius return port; 1738290001Sglebius} 1739290001Sglebius 1740290001Sglebiusstruct evdns_server_port * 1741290001Sglebiusevdns_add_server_port(evutil_socket_t socket, int flags, evdns_request_callback_fn_type cb, void *user_data) 1742290001Sglebius{ 1743290001Sglebius return evdns_add_server_port_with_base(NULL, socket, flags, cb, user_data); 1744290001Sglebius} 1745290001Sglebius 1746290001Sglebius/* exported function */ 1747290001Sglebiusvoid 1748290001Sglebiusevdns_close_server_port(struct evdns_server_port *port) 1749290001Sglebius{ 1750290001Sglebius EVDNS_LOCK(port); 1751290001Sglebius if (--port->refcnt == 0) { 1752290001Sglebius EVDNS_UNLOCK(port); 1753290001Sglebius server_port_free(port); 1754290001Sglebius } else { 1755290001Sglebius port->closing = 1; 1756290001Sglebius } 1757290001Sglebius} 1758290001Sglebius 1759290001Sglebius/* exported function */ 1760290001Sglebiusint 1761290001Sglebiusevdns_server_request_add_reply(struct evdns_server_request *req_, int section, const char *name, int type, int class, int ttl, int datalen, int is_name, const char *data) 1762290001Sglebius{ 1763290001Sglebius struct server_request *req = TO_SERVER_REQUEST(req_); 1764290001Sglebius struct server_reply_item **itemp, *item; 1765290001Sglebius int *countp; 1766290001Sglebius int result = -1; 1767290001Sglebius 1768290001Sglebius EVDNS_LOCK(req->port); 1769290001Sglebius if (req->response) /* have we already answered? */ 1770290001Sglebius goto done; 1771290001Sglebius 1772290001Sglebius switch (section) { 1773290001Sglebius case EVDNS_ANSWER_SECTION: 1774290001Sglebius itemp = &req->answer; 1775290001Sglebius countp = &req->n_answer; 1776290001Sglebius break; 1777290001Sglebius case EVDNS_AUTHORITY_SECTION: 1778290001Sglebius itemp = &req->authority; 1779290001Sglebius countp = &req->n_authority; 1780290001Sglebius break; 1781290001Sglebius case EVDNS_ADDITIONAL_SECTION: 1782290001Sglebius itemp = &req->additional; 1783290001Sglebius countp = &req->n_additional; 1784290001Sglebius break; 1785290001Sglebius default: 1786290001Sglebius goto done; 1787290001Sglebius } 1788290001Sglebius while (*itemp) { 1789290001Sglebius itemp = &((*itemp)->next); 1790290001Sglebius } 1791290001Sglebius item = mm_malloc(sizeof(struct server_reply_item)); 1792290001Sglebius if (!item) 1793290001Sglebius goto done; 1794290001Sglebius item->next = NULL; 1795290001Sglebius if (!(item->name = mm_strdup(name))) { 1796290001Sglebius mm_free(item); 1797290001Sglebius goto done; 1798290001Sglebius } 1799290001Sglebius item->type = type; 1800290001Sglebius item->dns_question_class = class; 1801290001Sglebius item->ttl = ttl; 1802290001Sglebius item->is_name = is_name != 0; 1803290001Sglebius item->datalen = 0; 1804290001Sglebius item->data = NULL; 1805290001Sglebius if (data) { 1806290001Sglebius if (item->is_name) { 1807290001Sglebius if (!(item->data = mm_strdup(data))) { 1808290001Sglebius mm_free(item->name); 1809290001Sglebius mm_free(item); 1810290001Sglebius goto done; 1811290001Sglebius } 1812290001Sglebius item->datalen = (u16)-1; 1813290001Sglebius } else { 1814290001Sglebius if (!(item->data = mm_malloc(datalen))) { 1815290001Sglebius mm_free(item->name); 1816290001Sglebius mm_free(item); 1817290001Sglebius goto done; 1818290001Sglebius } 1819290001Sglebius item->datalen = datalen; 1820290001Sglebius memcpy(item->data, data, datalen); 1821290001Sglebius } 1822290001Sglebius } 1823290001Sglebius 1824290001Sglebius *itemp = item; 1825290001Sglebius ++(*countp); 1826290001Sglebius result = 0; 1827290001Sglebiusdone: 1828290001Sglebius EVDNS_UNLOCK(req->port); 1829290001Sglebius return result; 1830290001Sglebius} 1831290001Sglebius 1832290001Sglebius/* exported function */ 1833290001Sglebiusint 1834290001Sglebiusevdns_server_request_add_a_reply(struct evdns_server_request *req, const char *name, int n, const void *addrs, int ttl) 1835290001Sglebius{ 1836290001Sglebius return evdns_server_request_add_reply( 1837290001Sglebius req, EVDNS_ANSWER_SECTION, name, TYPE_A, CLASS_INET, 1838290001Sglebius ttl, n*4, 0, addrs); 1839290001Sglebius} 1840290001Sglebius 1841290001Sglebius/* exported function */ 1842290001Sglebiusint 1843290001Sglebiusevdns_server_request_add_aaaa_reply(struct evdns_server_request *req, const char *name, int n, const void *addrs, int ttl) 1844290001Sglebius{ 1845290001Sglebius return evdns_server_request_add_reply( 1846290001Sglebius req, EVDNS_ANSWER_SECTION, name, TYPE_AAAA, CLASS_INET, 1847290001Sglebius ttl, n*16, 0, addrs); 1848290001Sglebius} 1849290001Sglebius 1850290001Sglebius/* exported function */ 1851290001Sglebiusint 1852290001Sglebiusevdns_server_request_add_ptr_reply(struct evdns_server_request *req, struct in_addr *in, const char *inaddr_name, const char *hostname, int ttl) 1853290001Sglebius{ 1854290001Sglebius u32 a; 1855290001Sglebius char buf[32]; 1856290001Sglebius if (in && inaddr_name) 1857290001Sglebius return -1; 1858290001Sglebius else if (!in && !inaddr_name) 1859290001Sglebius return -1; 1860290001Sglebius if (in) { 1861290001Sglebius a = ntohl(in->s_addr); 1862290001Sglebius evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa", 1863290001Sglebius (int)(u8)((a )&0xff), 1864290001Sglebius (int)(u8)((a>>8 )&0xff), 1865290001Sglebius (int)(u8)((a>>16)&0xff), 1866290001Sglebius (int)(u8)((a>>24)&0xff)); 1867290001Sglebius inaddr_name = buf; 1868290001Sglebius } 1869290001Sglebius return evdns_server_request_add_reply( 1870290001Sglebius req, EVDNS_ANSWER_SECTION, inaddr_name, TYPE_PTR, CLASS_INET, 1871290001Sglebius ttl, -1, 1, hostname); 1872290001Sglebius} 1873290001Sglebius 1874290001Sglebius/* exported function */ 1875290001Sglebiusint 1876290001Sglebiusevdns_server_request_add_cname_reply(struct evdns_server_request *req, const char *name, const char *cname, int ttl) 1877290001Sglebius{ 1878290001Sglebius return evdns_server_request_add_reply( 1879290001Sglebius req, EVDNS_ANSWER_SECTION, name, TYPE_CNAME, CLASS_INET, 1880290001Sglebius ttl, -1, 1, cname); 1881290001Sglebius} 1882290001Sglebius 1883290001Sglebius/* exported function */ 1884290001Sglebiusvoid 1885290001Sglebiusevdns_server_request_set_flags(struct evdns_server_request *exreq, int flags) 1886290001Sglebius{ 1887290001Sglebius struct server_request *req = TO_SERVER_REQUEST(exreq); 1888290001Sglebius req->base.flags &= ~(EVDNS_FLAGS_AA|EVDNS_FLAGS_RD); 1889290001Sglebius req->base.flags |= flags; 1890290001Sglebius} 1891290001Sglebius 1892290001Sglebiusstatic int 1893290001Sglebiusevdns_server_request_format_response(struct server_request *req, int err) 1894290001Sglebius{ 1895290001Sglebius unsigned char buf[1500]; 1896290001Sglebius size_t buf_len = sizeof(buf); 1897290001Sglebius off_t j = 0, r; 1898290001Sglebius u16 t_; 1899290001Sglebius u32 t32_; 1900290001Sglebius int i; 1901290001Sglebius u16 flags; 1902290001Sglebius struct dnslabel_table table; 1903290001Sglebius 1904290001Sglebius if (err < 0 || err > 15) return -1; 1905290001Sglebius 1906290001Sglebius /* Set response bit and error code; copy OPCODE and RD fields from 1907290001Sglebius * question; copy RA and AA if set by caller. */ 1908290001Sglebius flags = req->base.flags; 1909290001Sglebius flags |= (0x8000 | err); 1910290001Sglebius 1911290001Sglebius dnslabel_table_init(&table); 1912290001Sglebius APPEND16(req->trans_id); 1913290001Sglebius APPEND16(flags); 1914290001Sglebius APPEND16(req->base.nquestions); 1915290001Sglebius APPEND16(req->n_answer); 1916290001Sglebius APPEND16(req->n_authority); 1917290001Sglebius APPEND16(req->n_additional); 1918290001Sglebius 1919290001Sglebius /* Add questions. */ 1920290001Sglebius for (i=0; i < req->base.nquestions; ++i) { 1921290001Sglebius const char *s = req->base.questions[i]->name; 1922290001Sglebius j = dnsname_to_labels(buf, buf_len, j, s, strlen(s), &table); 1923290001Sglebius if (j < 0) { 1924290001Sglebius dnslabel_clear(&table); 1925290001Sglebius return (int) j; 1926290001Sglebius } 1927290001Sglebius APPEND16(req->base.questions[i]->type); 1928290001Sglebius APPEND16(req->base.questions[i]->dns_question_class); 1929290001Sglebius } 1930290001Sglebius 1931290001Sglebius /* Add answer, authority, and additional sections. */ 1932290001Sglebius for (i=0; i<3; ++i) { 1933290001Sglebius struct server_reply_item *item; 1934290001Sglebius if (i==0) 1935290001Sglebius item = req->answer; 1936290001Sglebius else if (i==1) 1937290001Sglebius item = req->authority; 1938290001Sglebius else 1939290001Sglebius item = req->additional; 1940290001Sglebius while (item) { 1941290001Sglebius r = dnsname_to_labels(buf, buf_len, j, item->name, strlen(item->name), &table); 1942290001Sglebius if (r < 0) 1943290001Sglebius goto overflow; 1944290001Sglebius j = r; 1945290001Sglebius 1946290001Sglebius APPEND16(item->type); 1947290001Sglebius APPEND16(item->dns_question_class); 1948290001Sglebius APPEND32(item->ttl); 1949290001Sglebius if (item->is_name) { 1950290001Sglebius off_t len_idx = j, name_start; 1951290001Sglebius j += 2; 1952290001Sglebius name_start = j; 1953290001Sglebius r = dnsname_to_labels(buf, buf_len, j, item->data, strlen(item->data), &table); 1954290001Sglebius if (r < 0) 1955290001Sglebius goto overflow; 1956290001Sglebius j = r; 1957290001Sglebius t_ = htons( (short) (j-name_start) ); 1958290001Sglebius memcpy(buf+len_idx, &t_, 2); 1959290001Sglebius } else { 1960290001Sglebius APPEND16(item->datalen); 1961290001Sglebius if (j+item->datalen > (off_t)buf_len) 1962290001Sglebius goto overflow; 1963290001Sglebius memcpy(buf+j, item->data, item->datalen); 1964290001Sglebius j += item->datalen; 1965290001Sglebius } 1966290001Sglebius item = item->next; 1967290001Sglebius } 1968290001Sglebius } 1969290001Sglebius 1970290001Sglebius if (j > 512) { 1971290001Sglebiusoverflow: 1972290001Sglebius j = 512; 1973290001Sglebius buf[2] |= 0x02; /* set the truncated bit. */ 1974290001Sglebius } 1975290001Sglebius 1976290001Sglebius req->response_len = j; 1977290001Sglebius 1978290001Sglebius if (!(req->response = mm_malloc(req->response_len))) { 1979290001Sglebius server_request_free_answers(req); 1980290001Sglebius dnslabel_clear(&table); 1981290001Sglebius return (-1); 1982290001Sglebius } 1983290001Sglebius memcpy(req->response, buf, req->response_len); 1984290001Sglebius server_request_free_answers(req); 1985290001Sglebius dnslabel_clear(&table); 1986290001Sglebius return (0); 1987290001Sglebius} 1988290001Sglebius 1989290001Sglebius/* exported function */ 1990290001Sglebiusint 1991290001Sglebiusevdns_server_request_respond(struct evdns_server_request *req_, int err) 1992290001Sglebius{ 1993290001Sglebius struct server_request *req = TO_SERVER_REQUEST(req_); 1994290001Sglebius struct evdns_server_port *port = req->port; 1995290001Sglebius int r = -1; 1996290001Sglebius 1997290001Sglebius EVDNS_LOCK(port); 1998290001Sglebius if (!req->response) { 1999290001Sglebius if ((r = evdns_server_request_format_response(req, err))<0) 2000290001Sglebius goto done; 2001290001Sglebius } 2002290001Sglebius 2003290001Sglebius r = sendto(port->socket, req->response, (int)req->response_len, 0, 2004290001Sglebius (struct sockaddr*) &req->addr, (ev_socklen_t)req->addrlen); 2005290001Sglebius if (r<0) { 2006290001Sglebius int sock_err = evutil_socket_geterror(port->socket); 2007290001Sglebius if (EVUTIL_ERR_RW_RETRIABLE(sock_err)) 2008290001Sglebius goto done; 2009290001Sglebius 2010290001Sglebius if (port->pending_replies) { 2011290001Sglebius req->prev_pending = port->pending_replies->prev_pending; 2012290001Sglebius req->next_pending = port->pending_replies; 2013290001Sglebius req->prev_pending->next_pending = 2014290001Sglebius req->next_pending->prev_pending = req; 2015290001Sglebius } else { 2016290001Sglebius req->prev_pending = req->next_pending = req; 2017290001Sglebius port->pending_replies = req; 2018290001Sglebius port->choked = 1; 2019290001Sglebius 2020290001Sglebius (void) event_del(&port->event); 2021290001Sglebius event_assign(&port->event, port->event_base, port->socket, (port->closing?0:EV_READ) | EV_WRITE | EV_PERSIST, server_port_ready_callback, port); 2022290001Sglebius 2023290001Sglebius if (event_add(&port->event, NULL) < 0) { 2024290001Sglebius log(EVDNS_LOG_WARN, "Error from libevent when adding event for DNS server"); 2025290001Sglebius } 2026290001Sglebius 2027290001Sglebius } 2028290001Sglebius 2029290001Sglebius r = 1; 2030290001Sglebius goto done; 2031290001Sglebius } 2032290001Sglebius if (server_request_free(req)) { 2033290001Sglebius r = 0; 2034290001Sglebius goto done; 2035290001Sglebius } 2036290001Sglebius 2037290001Sglebius if (port->pending_replies) 2038290001Sglebius server_port_flush(port); 2039290001Sglebius 2040290001Sglebius r = 0; 2041290001Sglebiusdone: 2042290001Sglebius EVDNS_UNLOCK(port); 2043290001Sglebius return r; 2044290001Sglebius} 2045290001Sglebius 2046290001Sglebius/* Free all storage held by RRs in req. */ 2047290001Sglebiusstatic void 2048290001Sglebiusserver_request_free_answers(struct server_request *req) 2049290001Sglebius{ 2050290001Sglebius struct server_reply_item *victim, *next, **list; 2051290001Sglebius int i; 2052290001Sglebius for (i = 0; i < 3; ++i) { 2053290001Sglebius if (i==0) 2054290001Sglebius list = &req->answer; 2055290001Sglebius else if (i==1) 2056290001Sglebius list = &req->authority; 2057290001Sglebius else 2058290001Sglebius list = &req->additional; 2059290001Sglebius 2060290001Sglebius victim = *list; 2061290001Sglebius while (victim) { 2062290001Sglebius next = victim->next; 2063290001Sglebius mm_free(victim->name); 2064290001Sglebius if (victim->data) 2065290001Sglebius mm_free(victim->data); 2066290001Sglebius mm_free(victim); 2067290001Sglebius victim = next; 2068290001Sglebius } 2069290001Sglebius *list = NULL; 2070290001Sglebius } 2071290001Sglebius} 2072290001Sglebius 2073290001Sglebius/* Free all storage held by req, and remove links to it. */ 2074290001Sglebius/* return true iff we just wound up freeing the server_port. */ 2075290001Sglebiusstatic int 2076290001Sglebiusserver_request_free(struct server_request *req) 2077290001Sglebius{ 2078290001Sglebius int i, rc=1, lock=0; 2079290001Sglebius if (req->base.questions) { 2080290001Sglebius for (i = 0; i < req->base.nquestions; ++i) 2081290001Sglebius mm_free(req->base.questions[i]); 2082290001Sglebius mm_free(req->base.questions); 2083290001Sglebius } 2084290001Sglebius 2085290001Sglebius if (req->port) { 2086290001Sglebius EVDNS_LOCK(req->port); 2087290001Sglebius lock=1; 2088290001Sglebius if (req->port->pending_replies == req) { 2089290001Sglebius if (req->next_pending && req->next_pending != req) 2090290001Sglebius req->port->pending_replies = req->next_pending; 2091290001Sglebius else 2092290001Sglebius req->port->pending_replies = NULL; 2093290001Sglebius } 2094290001Sglebius rc = --req->port->refcnt; 2095290001Sglebius } 2096290001Sglebius 2097290001Sglebius if (req->response) { 2098290001Sglebius mm_free(req->response); 2099290001Sglebius } 2100290001Sglebius 2101290001Sglebius server_request_free_answers(req); 2102290001Sglebius 2103290001Sglebius if (req->next_pending && req->next_pending != req) { 2104290001Sglebius req->next_pending->prev_pending = req->prev_pending; 2105290001Sglebius req->prev_pending->next_pending = req->next_pending; 2106290001Sglebius } 2107290001Sglebius 2108290001Sglebius if (rc == 0) { 2109290001Sglebius EVDNS_UNLOCK(req->port); /* ????? nickm */ 2110290001Sglebius server_port_free(req->port); 2111290001Sglebius mm_free(req); 2112290001Sglebius return (1); 2113290001Sglebius } 2114290001Sglebius if (lock) 2115290001Sglebius EVDNS_UNLOCK(req->port); 2116290001Sglebius mm_free(req); 2117290001Sglebius return (0); 2118290001Sglebius} 2119290001Sglebius 2120290001Sglebius/* Free all storage held by an evdns_server_port. Only called when */ 2121290001Sglebiusstatic void 2122290001Sglebiusserver_port_free(struct evdns_server_port *port) 2123290001Sglebius{ 2124290001Sglebius EVUTIL_ASSERT(port); 2125290001Sglebius EVUTIL_ASSERT(!port->refcnt); 2126290001Sglebius EVUTIL_ASSERT(!port->pending_replies); 2127290001Sglebius if (port->socket > 0) { 2128290001Sglebius evutil_closesocket(port->socket); 2129290001Sglebius port->socket = -1; 2130290001Sglebius } 2131290001Sglebius (void) event_del(&port->event); 2132290001Sglebius event_debug_unassign(&port->event); 2133290001Sglebius EVTHREAD_FREE_LOCK(port->lock, EVTHREAD_LOCKTYPE_RECURSIVE); 2134290001Sglebius mm_free(port); 2135290001Sglebius} 2136290001Sglebius 2137290001Sglebius/* exported function */ 2138290001Sglebiusint 2139290001Sglebiusevdns_server_request_drop(struct evdns_server_request *req_) 2140290001Sglebius{ 2141290001Sglebius struct server_request *req = TO_SERVER_REQUEST(req_); 2142290001Sglebius server_request_free(req); 2143290001Sglebius return 0; 2144290001Sglebius} 2145290001Sglebius 2146290001Sglebius/* exported function */ 2147290001Sglebiusint 2148290001Sglebiusevdns_server_request_get_requesting_addr(struct evdns_server_request *req_, struct sockaddr *sa, int addr_len) 2149290001Sglebius{ 2150290001Sglebius struct server_request *req = TO_SERVER_REQUEST(req_); 2151290001Sglebius if (addr_len < (int)req->addrlen) 2152290001Sglebius return -1; 2153290001Sglebius memcpy(sa, &(req->addr), req->addrlen); 2154290001Sglebius return req->addrlen; 2155290001Sglebius} 2156290001Sglebius 2157290001Sglebius#undef APPEND16 2158290001Sglebius#undef APPEND32 2159290001Sglebius 2160290001Sglebius/* this is a libevent callback function which is called when a request */ 2161290001Sglebius/* has timed out. */ 2162290001Sglebiusstatic void 2163290001Sglebiusevdns_request_timeout_callback(evutil_socket_t fd, short events, void *arg) { 2164290001Sglebius struct request *const req = (struct request *) arg; 2165290001Sglebius struct evdns_base *base = req->base; 2166290001Sglebius 2167290001Sglebius (void) fd; 2168290001Sglebius (void) events; 2169290001Sglebius 2170290001Sglebius log(EVDNS_LOG_DEBUG, "Request %p timed out", arg); 2171290001Sglebius EVDNS_LOCK(base); 2172290001Sglebius 2173290001Sglebius if (req->tx_count >= req->base->global_max_retransmits) { 2174290001Sglebius struct nameserver *ns = req->ns; 2175290001Sglebius /* this request has failed */ 2176290001Sglebius log(EVDNS_LOG_DEBUG, "Giving up on request %p; tx_count==%d", 2177290001Sglebius arg, req->tx_count); 2178290001Sglebius reply_schedule_callback(req, 0, DNS_ERR_TIMEOUT, NULL); 2179290001Sglebius 2180290001Sglebius request_finished(req, &REQ_HEAD(req->base, req->trans_id), 1); 2181290001Sglebius nameserver_failed(ns, "request timed out."); 2182290001Sglebius } else { 2183290001Sglebius /* retransmit it */ 2184290001Sglebius log(EVDNS_LOG_DEBUG, "Retransmitting request %p; tx_count==%d", 2185290001Sglebius arg, req->tx_count); 2186290001Sglebius (void) evtimer_del(&req->timeout_event); 2187290001Sglebius request_swap_ns(req, nameserver_pick(base)); 2188290001Sglebius evdns_request_transmit(req); 2189290001Sglebius 2190290001Sglebius req->ns->timedout++; 2191290001Sglebius if (req->ns->timedout > req->base->global_max_nameserver_timeout) { 2192290001Sglebius req->ns->timedout = 0; 2193290001Sglebius nameserver_failed(req->ns, "request timed out."); 2194290001Sglebius } 2195290001Sglebius } 2196290001Sglebius 2197290001Sglebius EVDNS_UNLOCK(base); 2198290001Sglebius} 2199290001Sglebius 2200290001Sglebius/* try to send a request to a given server. */ 2201290001Sglebius/* */ 2202290001Sglebius/* return: */ 2203290001Sglebius/* 0 ok */ 2204290001Sglebius/* 1 temporary failure */ 2205290001Sglebius/* 2 other failure */ 2206290001Sglebiusstatic int 2207290001Sglebiusevdns_request_transmit_to(struct request *req, struct nameserver *server) { 2208290001Sglebius int r; 2209290001Sglebius ASSERT_LOCKED(req->base); 2210290001Sglebius ASSERT_VALID_REQUEST(req); 2211290001Sglebius 2212290001Sglebius if (server->requests_inflight == 1 && 2213290001Sglebius req->base->disable_when_inactive && 2214290001Sglebius event_add(&server->event, NULL) < 0) { 2215290001Sglebius return 1; 2216290001Sglebius } 2217290001Sglebius 2218290001Sglebius r = sendto(server->socket, (void*)req->request, req->request_len, 0, 2219290001Sglebius (struct sockaddr *)&server->address, server->addrlen); 2220290001Sglebius if (r < 0) { 2221290001Sglebius int err = evutil_socket_geterror(server->socket); 2222290001Sglebius if (EVUTIL_ERR_RW_RETRIABLE(err)) 2223290001Sglebius return 1; 2224290001Sglebius nameserver_failed(req->ns, evutil_socket_error_to_string(err)); 2225290001Sglebius return 2; 2226290001Sglebius } else if (r != (int)req->request_len) { 2227290001Sglebius return 1; /* short write */ 2228290001Sglebius } else { 2229290001Sglebius return 0; 2230290001Sglebius } 2231290001Sglebius} 2232290001Sglebius 2233290001Sglebius/* try to send a request, updating the fields of the request */ 2234290001Sglebius/* as needed */ 2235290001Sglebius/* */ 2236290001Sglebius/* return: */ 2237290001Sglebius/* 0 ok */ 2238290001Sglebius/* 1 failed */ 2239290001Sglebiusstatic int 2240290001Sglebiusevdns_request_transmit(struct request *req) { 2241290001Sglebius int retcode = 0, r; 2242290001Sglebius 2243290001Sglebius ASSERT_LOCKED(req->base); 2244290001Sglebius ASSERT_VALID_REQUEST(req); 2245290001Sglebius /* if we fail to send this packet then this flag marks it */ 2246290001Sglebius /* for evdns_transmit */ 2247290001Sglebius req->transmit_me = 1; 2248290001Sglebius EVUTIL_ASSERT(req->trans_id != 0xffff); 2249290001Sglebius 2250290001Sglebius if (!req->ns) 2251290001Sglebius { 2252290001Sglebius /* unable to transmit request if no nameservers */ 2253290001Sglebius return 1; 2254290001Sglebius } 2255290001Sglebius 2256290001Sglebius if (req->ns->choked) { 2257290001Sglebius /* don't bother trying to write to a socket */ 2258290001Sglebius /* which we have had EAGAIN from */ 2259290001Sglebius return 1; 2260290001Sglebius } 2261290001Sglebius 2262290001Sglebius r = evdns_request_transmit_to(req, req->ns); 2263290001Sglebius switch (r) { 2264290001Sglebius case 1: 2265290001Sglebius /* temp failure */ 2266290001Sglebius req->ns->choked = 1; 2267290001Sglebius nameserver_write_waiting(req->ns, 1); 2268290001Sglebius return 1; 2269290001Sglebius case 2: 2270290001Sglebius /* failed to transmit the request entirely. */ 2271290001Sglebius retcode = 1; 2272290001Sglebius /* fall through: we'll set a timeout, which will time out, 2273290001Sglebius * and make us retransmit the request anyway. */ 2274290001Sglebius default: 2275290001Sglebius /* all ok */ 2276290001Sglebius log(EVDNS_LOG_DEBUG, 2277290001Sglebius "Setting timeout for request %p, sent to nameserver %p", req, req->ns); 2278290001Sglebius if (evtimer_add(&req->timeout_event, &req->base->global_timeout) < 0) { 2279290001Sglebius log(EVDNS_LOG_WARN, 2280290001Sglebius "Error from libevent when adding timer for request %p", 2281290001Sglebius req); 2282290001Sglebius /* ???? Do more? */ 2283290001Sglebius } 2284290001Sglebius req->tx_count++; 2285290001Sglebius req->transmit_me = 0; 2286290001Sglebius return retcode; 2287290001Sglebius } 2288290001Sglebius} 2289290001Sglebius 2290290001Sglebiusstatic void 2291290001Sglebiusnameserver_probe_callback(int result, char type, int count, int ttl, void *addresses, void *arg) { 2292290001Sglebius struct nameserver *const ns = (struct nameserver *) arg; 2293290001Sglebius (void) type; 2294290001Sglebius (void) count; 2295290001Sglebius (void) ttl; 2296290001Sglebius (void) addresses; 2297290001Sglebius 2298290001Sglebius if (result == DNS_ERR_CANCEL) { 2299290001Sglebius /* We canceled this request because the nameserver came up 2300290001Sglebius * for some other reason. Do not change our opinion about 2301290001Sglebius * the nameserver. */ 2302290001Sglebius return; 2303290001Sglebius } 2304290001Sglebius 2305290001Sglebius EVDNS_LOCK(ns->base); 2306290001Sglebius ns->probe_request = NULL; 2307290001Sglebius if (result == DNS_ERR_NONE || result == DNS_ERR_NOTEXIST) { 2308290001Sglebius /* this is a good reply */ 2309290001Sglebius nameserver_up(ns); 2310290001Sglebius } else { 2311290001Sglebius nameserver_probe_failed(ns); 2312290001Sglebius } 2313290001Sglebius EVDNS_UNLOCK(ns->base); 2314290001Sglebius} 2315290001Sglebius 2316290001Sglebiusstatic void 2317290001Sglebiusnameserver_send_probe(struct nameserver *const ns) { 2318290001Sglebius struct evdns_request *handle; 2319290001Sglebius struct request *req; 2320290001Sglebius char addrbuf[128]; 2321290001Sglebius /* here we need to send a probe to a given nameserver */ 2322290001Sglebius /* in the hope that it is up now. */ 2323290001Sglebius 2324290001Sglebius ASSERT_LOCKED(ns->base); 2325290001Sglebius log(EVDNS_LOG_DEBUG, "Sending probe to %s", 2326290001Sglebius evutil_format_sockaddr_port_( 2327290001Sglebius (struct sockaddr *)&ns->address, 2328290001Sglebius addrbuf, sizeof(addrbuf))); 2329290001Sglebius handle = mm_calloc(1, sizeof(*handle)); 2330290001Sglebius if (!handle) return; 2331290001Sglebius req = request_new(ns->base, handle, TYPE_A, "google.com", DNS_QUERY_NO_SEARCH, nameserver_probe_callback, ns); 2332290001Sglebius if (!req) { 2333290001Sglebius mm_free(handle); 2334290001Sglebius return; 2335290001Sglebius } 2336290001Sglebius ns->probe_request = handle; 2337290001Sglebius /* we force this into the inflight queue no matter what */ 2338290001Sglebius request_trans_id_set(req, transaction_id_pick(ns->base)); 2339290001Sglebius req->ns = ns; 2340290001Sglebius request_submit(req); 2341290001Sglebius} 2342290001Sglebius 2343290001Sglebius/* returns: */ 2344290001Sglebius/* 0 didn't try to transmit anything */ 2345290001Sglebius/* 1 tried to transmit something */ 2346290001Sglebiusstatic int 2347290001Sglebiusevdns_transmit(struct evdns_base *base) { 2348290001Sglebius char did_try_to_transmit = 0; 2349290001Sglebius int i; 2350290001Sglebius 2351290001Sglebius ASSERT_LOCKED(base); 2352290001Sglebius for (i = 0; i < base->n_req_heads; ++i) { 2353290001Sglebius if (base->req_heads[i]) { 2354290001Sglebius struct request *const started_at = base->req_heads[i], *req = started_at; 2355290001Sglebius /* first transmit all the requests which are currently waiting */ 2356290001Sglebius do { 2357290001Sglebius if (req->transmit_me) { 2358290001Sglebius did_try_to_transmit = 1; 2359290001Sglebius evdns_request_transmit(req); 2360290001Sglebius } 2361290001Sglebius 2362290001Sglebius req = req->next; 2363290001Sglebius } while (req != started_at); 2364290001Sglebius } 2365290001Sglebius } 2366290001Sglebius 2367290001Sglebius return did_try_to_transmit; 2368290001Sglebius} 2369290001Sglebius 2370290001Sglebius/* exported function */ 2371290001Sglebiusint 2372290001Sglebiusevdns_base_count_nameservers(struct evdns_base *base) 2373290001Sglebius{ 2374290001Sglebius const struct nameserver *server; 2375290001Sglebius int n = 0; 2376290001Sglebius 2377290001Sglebius EVDNS_LOCK(base); 2378290001Sglebius server = base->server_head; 2379290001Sglebius if (!server) 2380290001Sglebius goto done; 2381290001Sglebius do { 2382290001Sglebius ++n; 2383290001Sglebius server = server->next; 2384290001Sglebius } while (server != base->server_head); 2385290001Sglebiusdone: 2386290001Sglebius EVDNS_UNLOCK(base); 2387290001Sglebius return n; 2388290001Sglebius} 2389290001Sglebius 2390290001Sglebiusint 2391290001Sglebiusevdns_count_nameservers(void) 2392290001Sglebius{ 2393290001Sglebius return evdns_base_count_nameservers(current_base); 2394290001Sglebius} 2395290001Sglebius 2396290001Sglebius/* exported function */ 2397290001Sglebiusint 2398290001Sglebiusevdns_base_clear_nameservers_and_suspend(struct evdns_base *base) 2399290001Sglebius{ 2400290001Sglebius struct nameserver *server, *started_at; 2401290001Sglebius int i; 2402290001Sglebius 2403290001Sglebius EVDNS_LOCK(base); 2404290001Sglebius server = base->server_head; 2405290001Sglebius started_at = base->server_head; 2406290001Sglebius if (!server) { 2407290001Sglebius EVDNS_UNLOCK(base); 2408290001Sglebius return 0; 2409290001Sglebius } 2410290001Sglebius while (1) { 2411290001Sglebius struct nameserver *next = server->next; 2412290001Sglebius (void) event_del(&server->event); 2413290001Sglebius if (evtimer_initialized(&server->timeout_event)) 2414290001Sglebius (void) evtimer_del(&server->timeout_event); 2415290001Sglebius if (server->probe_request) { 2416290001Sglebius evdns_cancel_request(server->base, server->probe_request); 2417290001Sglebius server->probe_request = NULL; 2418290001Sglebius } 2419290001Sglebius if (server->socket >= 0) 2420290001Sglebius evutil_closesocket(server->socket); 2421290001Sglebius mm_free(server); 2422290001Sglebius if (next == started_at) 2423290001Sglebius break; 2424290001Sglebius server = next; 2425290001Sglebius } 2426290001Sglebius base->server_head = NULL; 2427290001Sglebius base->global_good_nameservers = 0; 2428290001Sglebius 2429290001Sglebius for (i = 0; i < base->n_req_heads; ++i) { 2430290001Sglebius struct request *req, *req_started_at; 2431290001Sglebius req = req_started_at = base->req_heads[i]; 2432290001Sglebius while (req) { 2433290001Sglebius struct request *next = req->next; 2434290001Sglebius req->tx_count = req->reissue_count = 0; 2435290001Sglebius req->ns = NULL; 2436290001Sglebius /* ???? What to do about searches? */ 2437290001Sglebius (void) evtimer_del(&req->timeout_event); 2438290001Sglebius req->trans_id = 0; 2439290001Sglebius req->transmit_me = 0; 2440290001Sglebius 2441290001Sglebius base->global_requests_waiting++; 2442290001Sglebius evdns_request_insert(req, &base->req_waiting_head); 2443290001Sglebius /* We want to insert these suspended elements at the front of 2444290001Sglebius * the waiting queue, since they were pending before any of 2445290001Sglebius * the waiting entries were added. This is a circular list, 2446290001Sglebius * so we can just shift the start back by one.*/ 2447290001Sglebius base->req_waiting_head = base->req_waiting_head->prev; 2448290001Sglebius 2449290001Sglebius if (next == req_started_at) 2450290001Sglebius break; 2451290001Sglebius req = next; 2452290001Sglebius } 2453290001Sglebius base->req_heads[i] = NULL; 2454290001Sglebius } 2455290001Sglebius 2456290001Sglebius base->global_requests_inflight = 0; 2457290001Sglebius 2458290001Sglebius EVDNS_UNLOCK(base); 2459290001Sglebius return 0; 2460290001Sglebius} 2461290001Sglebius 2462290001Sglebiusint 2463290001Sglebiusevdns_clear_nameservers_and_suspend(void) 2464290001Sglebius{ 2465290001Sglebius return evdns_base_clear_nameservers_and_suspend(current_base); 2466290001Sglebius} 2467290001Sglebius 2468290001Sglebius 2469290001Sglebius/* exported function */ 2470290001Sglebiusint 2471290001Sglebiusevdns_base_resume(struct evdns_base *base) 2472290001Sglebius{ 2473290001Sglebius EVDNS_LOCK(base); 2474290001Sglebius evdns_requests_pump_waiting_queue(base); 2475290001Sglebius EVDNS_UNLOCK(base); 2476290001Sglebius 2477290001Sglebius return 0; 2478290001Sglebius} 2479290001Sglebius 2480290001Sglebiusint 2481290001Sglebiusevdns_resume(void) 2482290001Sglebius{ 2483290001Sglebius return evdns_base_resume(current_base); 2484290001Sglebius} 2485290001Sglebius 2486290001Sglebiusstatic int 2487290001Sglebiusevdns_nameserver_add_impl_(struct evdns_base *base, const struct sockaddr *address, int addrlen) { 2488290001Sglebius /* first check to see if we already have this nameserver */ 2489290001Sglebius 2490290001Sglebius const struct nameserver *server = base->server_head, *const started_at = base->server_head; 2491290001Sglebius struct nameserver *ns; 2492290001Sglebius int err = 0; 2493290001Sglebius char addrbuf[128]; 2494290001Sglebius 2495290001Sglebius ASSERT_LOCKED(base); 2496290001Sglebius if (server) { 2497290001Sglebius do { 2498290001Sglebius if (!evutil_sockaddr_cmp((struct sockaddr*)&server->address, address, 1)) return 3; 2499290001Sglebius server = server->next; 2500290001Sglebius } while (server != started_at); 2501290001Sglebius } 2502290001Sglebius if (addrlen > (int)sizeof(ns->address)) { 2503290001Sglebius log(EVDNS_LOG_DEBUG, "Addrlen %d too long.", (int)addrlen); 2504290001Sglebius return 2; 2505290001Sglebius } 2506290001Sglebius 2507290001Sglebius ns = (struct nameserver *) mm_malloc(sizeof(struct nameserver)); 2508290001Sglebius if (!ns) return -1; 2509290001Sglebius 2510290001Sglebius memset(ns, 0, sizeof(struct nameserver)); 2511290001Sglebius ns->base = base; 2512290001Sglebius 2513290001Sglebius evtimer_assign(&ns->timeout_event, ns->base->event_base, nameserver_prod_callback, ns); 2514290001Sglebius 2515290001Sglebius ns->socket = evutil_socket_(address->sa_family, 2516290001Sglebius SOCK_DGRAM|EVUTIL_SOCK_NONBLOCK|EVUTIL_SOCK_CLOEXEC, 0); 2517290001Sglebius if (ns->socket < 0) { err = 1; goto out1; } 2518290001Sglebius 2519290001Sglebius if (base->global_outgoing_addrlen && 2520290001Sglebius !evutil_sockaddr_is_loopback_(address)) { 2521290001Sglebius if (bind(ns->socket, 2522290001Sglebius (struct sockaddr*)&base->global_outgoing_address, 2523290001Sglebius base->global_outgoing_addrlen) < 0) { 2524290001Sglebius log(EVDNS_LOG_WARN,"Couldn't bind to outgoing address"); 2525290001Sglebius err = 2; 2526290001Sglebius goto out2; 2527290001Sglebius } 2528290001Sglebius } 2529290001Sglebius 2530290001Sglebius memcpy(&ns->address, address, addrlen); 2531290001Sglebius ns->addrlen = addrlen; 2532290001Sglebius ns->state = 1; 2533290001Sglebius event_assign(&ns->event, ns->base->event_base, ns->socket, 2534290001Sglebius EV_READ | EV_PERSIST, nameserver_ready_callback, ns); 2535290001Sglebius if (!base->disable_when_inactive && event_add(&ns->event, NULL) < 0) { 2536290001Sglebius err = 2; 2537290001Sglebius goto out2; 2538290001Sglebius } 2539290001Sglebius 2540290001Sglebius log(EVDNS_LOG_DEBUG, "Added nameserver %s as %p", 2541290001Sglebius evutil_format_sockaddr_port_(address, addrbuf, sizeof(addrbuf)), ns); 2542290001Sglebius 2543290001Sglebius /* insert this nameserver into the list of them */ 2544290001Sglebius if (!base->server_head) { 2545290001Sglebius ns->next = ns->prev = ns; 2546290001Sglebius base->server_head = ns; 2547290001Sglebius } else { 2548290001Sglebius ns->next = base->server_head->next; 2549290001Sglebius ns->prev = base->server_head; 2550290001Sglebius base->server_head->next = ns; 2551290001Sglebius ns->next->prev = ns; 2552290001Sglebius } 2553290001Sglebius 2554290001Sglebius base->global_good_nameservers++; 2555290001Sglebius 2556290001Sglebius return 0; 2557290001Sglebius 2558290001Sglebiusout2: 2559290001Sglebius evutil_closesocket(ns->socket); 2560290001Sglebiusout1: 2561290001Sglebius event_debug_unassign(&ns->event); 2562290001Sglebius mm_free(ns); 2563290001Sglebius log(EVDNS_LOG_WARN, "Unable to add nameserver %s: error %d", 2564290001Sglebius evutil_format_sockaddr_port_(address, addrbuf, sizeof(addrbuf)), err); 2565290001Sglebius return err; 2566290001Sglebius} 2567290001Sglebius 2568290001Sglebius/* exported function */ 2569290001Sglebiusint 2570290001Sglebiusevdns_base_nameserver_add(struct evdns_base *base, unsigned long int address) 2571290001Sglebius{ 2572290001Sglebius struct sockaddr_in sin; 2573290001Sglebius int res; 2574290001Sglebius memset(&sin, 0, sizeof(sin)); 2575290001Sglebius sin.sin_addr.s_addr = address; 2576290001Sglebius sin.sin_port = htons(53); 2577290001Sglebius sin.sin_family = AF_INET; 2578290001Sglebius EVDNS_LOCK(base); 2579290001Sglebius res = evdns_nameserver_add_impl_(base, (struct sockaddr*)&sin, sizeof(sin)); 2580290001Sglebius EVDNS_UNLOCK(base); 2581290001Sglebius return res; 2582290001Sglebius} 2583290001Sglebius 2584290001Sglebiusint 2585290001Sglebiusevdns_nameserver_add(unsigned long int address) { 2586290001Sglebius if (!current_base) 2587290001Sglebius current_base = evdns_base_new(NULL, 0); 2588290001Sglebius return evdns_base_nameserver_add(current_base, address); 2589290001Sglebius} 2590290001Sglebius 2591290001Sglebiusstatic void 2592290001Sglebiussockaddr_setport(struct sockaddr *sa, ev_uint16_t port) 2593290001Sglebius{ 2594290001Sglebius if (sa->sa_family == AF_INET) { 2595290001Sglebius ((struct sockaddr_in *)sa)->sin_port = htons(port); 2596290001Sglebius } else if (sa->sa_family == AF_INET6) { 2597290001Sglebius ((struct sockaddr_in6 *)sa)->sin6_port = htons(port); 2598290001Sglebius } 2599290001Sglebius} 2600290001Sglebius 2601290001Sglebiusstatic ev_uint16_t 2602290001Sglebiussockaddr_getport(struct sockaddr *sa) 2603290001Sglebius{ 2604290001Sglebius if (sa->sa_family == AF_INET) { 2605290001Sglebius return ntohs(((struct sockaddr_in *)sa)->sin_port); 2606290001Sglebius } else if (sa->sa_family == AF_INET6) { 2607290001Sglebius return ntohs(((struct sockaddr_in6 *)sa)->sin6_port); 2608290001Sglebius } else { 2609290001Sglebius return 0; 2610290001Sglebius } 2611290001Sglebius} 2612290001Sglebius 2613290001Sglebius/* exported function */ 2614290001Sglebiusint 2615290001Sglebiusevdns_base_nameserver_ip_add(struct evdns_base *base, const char *ip_as_string) { 2616290001Sglebius struct sockaddr_storage ss; 2617290001Sglebius struct sockaddr *sa; 2618290001Sglebius int len = sizeof(ss); 2619290001Sglebius int res; 2620290001Sglebius if (evutil_parse_sockaddr_port(ip_as_string, (struct sockaddr *)&ss, 2621290001Sglebius &len)) { 2622290001Sglebius log(EVDNS_LOG_WARN, "Unable to parse nameserver address %s", 2623290001Sglebius ip_as_string); 2624290001Sglebius return 4; 2625290001Sglebius } 2626290001Sglebius sa = (struct sockaddr *) &ss; 2627290001Sglebius if (sockaddr_getport(sa) == 0) 2628290001Sglebius sockaddr_setport(sa, 53); 2629290001Sglebius 2630290001Sglebius EVDNS_LOCK(base); 2631290001Sglebius res = evdns_nameserver_add_impl_(base, sa, len); 2632290001Sglebius EVDNS_UNLOCK(base); 2633290001Sglebius return res; 2634290001Sglebius} 2635290001Sglebius 2636290001Sglebiusint 2637290001Sglebiusevdns_nameserver_ip_add(const char *ip_as_string) { 2638290001Sglebius if (!current_base) 2639290001Sglebius current_base = evdns_base_new(NULL, 0); 2640290001Sglebius return evdns_base_nameserver_ip_add(current_base, ip_as_string); 2641290001Sglebius} 2642290001Sglebius 2643290001Sglebiusint 2644290001Sglebiusevdns_base_nameserver_sockaddr_add(struct evdns_base *base, 2645290001Sglebius const struct sockaddr *sa, ev_socklen_t len, unsigned flags) 2646290001Sglebius{ 2647290001Sglebius int res; 2648290001Sglebius EVUTIL_ASSERT(base); 2649290001Sglebius EVDNS_LOCK(base); 2650290001Sglebius res = evdns_nameserver_add_impl_(base, sa, len); 2651290001Sglebius EVDNS_UNLOCK(base); 2652290001Sglebius return res; 2653290001Sglebius} 2654290001Sglebius 2655290001Sglebiusint 2656290001Sglebiusevdns_base_get_nameserver_addr(struct evdns_base *base, int idx, 2657290001Sglebius struct sockaddr *sa, ev_socklen_t len) 2658290001Sglebius{ 2659290001Sglebius int result = -1; 2660290001Sglebius int i; 2661290001Sglebius struct nameserver *server; 2662290001Sglebius EVDNS_LOCK(base); 2663290001Sglebius server = base->server_head; 2664290001Sglebius for (i = 0; i < idx && server; ++i, server = server->next) { 2665290001Sglebius if (server->next == base->server_head) 2666290001Sglebius goto done; 2667290001Sglebius } 2668290001Sglebius if (! server) 2669290001Sglebius goto done; 2670290001Sglebius 2671290001Sglebius if (server->addrlen > len) { 2672290001Sglebius result = (int) server->addrlen; 2673290001Sglebius goto done; 2674290001Sglebius } 2675290001Sglebius 2676290001Sglebius memcpy(sa, &server->address, server->addrlen); 2677290001Sglebius result = (int) server->addrlen; 2678290001Sglebiusdone: 2679290001Sglebius EVDNS_UNLOCK(base); 2680290001Sglebius return result; 2681290001Sglebius} 2682290001Sglebius 2683290001Sglebius/* remove from the queue */ 2684290001Sglebiusstatic void 2685290001Sglebiusevdns_request_remove(struct request *req, struct request **head) 2686290001Sglebius{ 2687290001Sglebius ASSERT_LOCKED(req->base); 2688290001Sglebius ASSERT_VALID_REQUEST(req); 2689290001Sglebius 2690290001Sglebius#if 0 2691290001Sglebius { 2692290001Sglebius struct request *ptr; 2693290001Sglebius int found = 0; 2694290001Sglebius EVUTIL_ASSERT(*head != NULL); 2695290001Sglebius 2696290001Sglebius ptr = *head; 2697290001Sglebius do { 2698290001Sglebius if (ptr == req) { 2699290001Sglebius found = 1; 2700290001Sglebius break; 2701290001Sglebius } 2702290001Sglebius ptr = ptr->next; 2703290001Sglebius } while (ptr != *head); 2704290001Sglebius EVUTIL_ASSERT(found); 2705290001Sglebius 2706290001Sglebius EVUTIL_ASSERT(req->next); 2707290001Sglebius } 2708290001Sglebius#endif 2709290001Sglebius 2710290001Sglebius if (req->next == req) { 2711290001Sglebius /* only item in the list */ 2712290001Sglebius *head = NULL; 2713290001Sglebius } else { 2714290001Sglebius req->next->prev = req->prev; 2715290001Sglebius req->prev->next = req->next; 2716290001Sglebius if (*head == req) *head = req->next; 2717290001Sglebius } 2718290001Sglebius req->next = req->prev = NULL; 2719290001Sglebius} 2720290001Sglebius 2721290001Sglebius/* insert into the tail of the queue */ 2722290001Sglebiusstatic void 2723290001Sglebiusevdns_request_insert(struct request *req, struct request **head) { 2724290001Sglebius ASSERT_LOCKED(req->base); 2725290001Sglebius ASSERT_VALID_REQUEST(req); 2726290001Sglebius if (!*head) { 2727290001Sglebius *head = req; 2728290001Sglebius req->next = req->prev = req; 2729290001Sglebius return; 2730290001Sglebius } 2731290001Sglebius 2732290001Sglebius req->prev = (*head)->prev; 2733290001Sglebius req->prev->next = req; 2734290001Sglebius req->next = *head; 2735290001Sglebius (*head)->prev = req; 2736290001Sglebius} 2737290001Sglebius 2738290001Sglebiusstatic int 2739290001Sglebiusstring_num_dots(const char *s) { 2740290001Sglebius int count = 0; 2741290001Sglebius while ((s = strchr(s, '.'))) { 2742290001Sglebius s++; 2743290001Sglebius count++; 2744290001Sglebius } 2745290001Sglebius return count; 2746290001Sglebius} 2747290001Sglebius 2748290001Sglebiusstatic struct request * 2749290001Sglebiusrequest_new(struct evdns_base *base, struct evdns_request *handle, int type, 2750290001Sglebius const char *name, int flags, evdns_callback_type callback, 2751290001Sglebius void *user_ptr) { 2752290001Sglebius 2753290001Sglebius const char issuing_now = 2754290001Sglebius (base->global_requests_inflight < base->global_max_requests_inflight) ? 1 : 0; 2755290001Sglebius 2756290001Sglebius const size_t name_len = strlen(name); 2757290001Sglebius const size_t request_max_len = evdns_request_len(name_len); 2758290001Sglebius const u16 trans_id = issuing_now ? transaction_id_pick(base) : 0xffff; 2759290001Sglebius /* the request data is alloced in a single block with the header */ 2760290001Sglebius struct request *const req = 2761290001Sglebius mm_malloc(sizeof(struct request) + request_max_len); 2762290001Sglebius int rlen; 2763290001Sglebius char namebuf[256]; 2764290001Sglebius (void) flags; 2765290001Sglebius 2766290001Sglebius ASSERT_LOCKED(base); 2767290001Sglebius 2768290001Sglebius if (!req) return NULL; 2769290001Sglebius 2770290001Sglebius if (name_len >= sizeof(namebuf)) { 2771290001Sglebius mm_free(req); 2772290001Sglebius return NULL; 2773290001Sglebius } 2774290001Sglebius 2775290001Sglebius memset(req, 0, sizeof(struct request)); 2776290001Sglebius req->base = base; 2777290001Sglebius 2778290001Sglebius evtimer_assign(&req->timeout_event, req->base->event_base, evdns_request_timeout_callback, req); 2779290001Sglebius 2780290001Sglebius if (base->global_randomize_case) { 2781290001Sglebius unsigned i; 2782290001Sglebius char randbits[(sizeof(namebuf)+7)/8]; 2783290001Sglebius strlcpy(namebuf, name, sizeof(namebuf)); 2784290001Sglebius evutil_secure_rng_get_bytes(randbits, (name_len+7)/8); 2785290001Sglebius for (i = 0; i < name_len; ++i) { 2786290001Sglebius if (EVUTIL_ISALPHA_(namebuf[i])) { 2787290001Sglebius if ((randbits[i >> 3] & (1<<(i & 7)))) 2788290001Sglebius namebuf[i] |= 0x20; 2789290001Sglebius else 2790290001Sglebius namebuf[i] &= ~0x20; 2791290001Sglebius } 2792290001Sglebius } 2793290001Sglebius name = namebuf; 2794290001Sglebius } 2795290001Sglebius 2796290001Sglebius /* request data lives just after the header */ 2797290001Sglebius req->request = ((u8 *) req) + sizeof(struct request); 2798290001Sglebius /* denotes that the request data shouldn't be free()ed */ 2799290001Sglebius req->request_appended = 1; 2800290001Sglebius rlen = evdns_request_data_build(name, name_len, trans_id, 2801290001Sglebius type, CLASS_INET, req->request, request_max_len); 2802290001Sglebius if (rlen < 0) 2803290001Sglebius goto err1; 2804290001Sglebius 2805290001Sglebius req->request_len = rlen; 2806290001Sglebius req->trans_id = trans_id; 2807290001Sglebius req->tx_count = 0; 2808290001Sglebius req->request_type = type; 2809290001Sglebius req->user_pointer = user_ptr; 2810290001Sglebius req->user_callback = callback; 2811290001Sglebius req->ns = issuing_now ? nameserver_pick(base) : NULL; 2812290001Sglebius req->next = req->prev = NULL; 2813290001Sglebius req->handle = handle; 2814290001Sglebius if (handle) { 2815290001Sglebius handle->current_req = req; 2816290001Sglebius handle->base = base; 2817290001Sglebius } 2818290001Sglebius 2819290001Sglebius return req; 2820290001Sglebiuserr1: 2821290001Sglebius mm_free(req); 2822290001Sglebius return NULL; 2823290001Sglebius} 2824290001Sglebius 2825290001Sglebiusstatic void 2826290001Sglebiusrequest_submit(struct request *const req) { 2827290001Sglebius struct evdns_base *base = req->base; 2828290001Sglebius ASSERT_LOCKED(base); 2829290001Sglebius ASSERT_VALID_REQUEST(req); 2830290001Sglebius if (req->ns) { 2831290001Sglebius /* if it has a nameserver assigned then this is going */ 2832290001Sglebius /* straight into the inflight queue */ 2833290001Sglebius evdns_request_insert(req, &REQ_HEAD(base, req->trans_id)); 2834290001Sglebius 2835290001Sglebius base->global_requests_inflight++; 2836290001Sglebius req->ns->requests_inflight++; 2837290001Sglebius 2838290001Sglebius evdns_request_transmit(req); 2839290001Sglebius } else { 2840290001Sglebius evdns_request_insert(req, &base->req_waiting_head); 2841290001Sglebius base->global_requests_waiting++; 2842290001Sglebius } 2843290001Sglebius} 2844290001Sglebius 2845290001Sglebius/* exported function */ 2846290001Sglebiusvoid 2847290001Sglebiusevdns_cancel_request(struct evdns_base *base, struct evdns_request *handle) 2848290001Sglebius{ 2849290001Sglebius struct request *req; 2850290001Sglebius 2851290001Sglebius if (!handle->current_req) 2852290001Sglebius return; 2853290001Sglebius 2854290001Sglebius if (!base) { 2855290001Sglebius /* This redundancy is silly; can we fix it? (Not for 2.0) XXXX */ 2856290001Sglebius base = handle->base; 2857290001Sglebius if (!base) 2858290001Sglebius base = handle->current_req->base; 2859290001Sglebius } 2860290001Sglebius 2861290001Sglebius EVDNS_LOCK(base); 2862290001Sglebius if (handle->pending_cb) { 2863290001Sglebius EVDNS_UNLOCK(base); 2864290001Sglebius return; 2865290001Sglebius } 2866290001Sglebius 2867290001Sglebius req = handle->current_req; 2868290001Sglebius ASSERT_VALID_REQUEST(req); 2869290001Sglebius 2870290001Sglebius reply_schedule_callback(req, 0, DNS_ERR_CANCEL, NULL); 2871290001Sglebius if (req->ns) { 2872290001Sglebius /* remove from inflight queue */ 2873290001Sglebius request_finished(req, &REQ_HEAD(base, req->trans_id), 1); 2874290001Sglebius } else { 2875290001Sglebius /* remove from global_waiting head */ 2876290001Sglebius request_finished(req, &base->req_waiting_head, 1); 2877290001Sglebius } 2878290001Sglebius EVDNS_UNLOCK(base); 2879290001Sglebius} 2880290001Sglebius 2881290001Sglebius/* exported function */ 2882290001Sglebiusstruct evdns_request * 2883290001Sglebiusevdns_base_resolve_ipv4(struct evdns_base *base, const char *name, int flags, 2884290001Sglebius evdns_callback_type callback, void *ptr) { 2885290001Sglebius struct evdns_request *handle; 2886290001Sglebius struct request *req; 2887290001Sglebius log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name); 2888290001Sglebius handle = mm_calloc(1, sizeof(*handle)); 2889290001Sglebius if (handle == NULL) 2890290001Sglebius return NULL; 2891290001Sglebius EVDNS_LOCK(base); 2892290001Sglebius if (flags & DNS_QUERY_NO_SEARCH) { 2893290001Sglebius req = 2894290001Sglebius request_new(base, handle, TYPE_A, name, flags, 2895290001Sglebius callback, ptr); 2896290001Sglebius if (req) 2897290001Sglebius request_submit(req); 2898290001Sglebius } else { 2899290001Sglebius search_request_new(base, handle, TYPE_A, name, flags, 2900290001Sglebius callback, ptr); 2901290001Sglebius } 2902290001Sglebius if (handle->current_req == NULL) { 2903290001Sglebius mm_free(handle); 2904290001Sglebius handle = NULL; 2905290001Sglebius } 2906290001Sglebius EVDNS_UNLOCK(base); 2907290001Sglebius return handle; 2908290001Sglebius} 2909290001Sglebius 2910290001Sglebiusint evdns_resolve_ipv4(const char *name, int flags, 2911290001Sglebius evdns_callback_type callback, void *ptr) 2912290001Sglebius{ 2913290001Sglebius return evdns_base_resolve_ipv4(current_base, name, flags, callback, ptr) 2914290001Sglebius ? 0 : -1; 2915290001Sglebius} 2916290001Sglebius 2917290001Sglebius 2918290001Sglebius/* exported function */ 2919290001Sglebiusstruct evdns_request * 2920290001Sglebiusevdns_base_resolve_ipv6(struct evdns_base *base, 2921290001Sglebius const char *name, int flags, 2922290001Sglebius evdns_callback_type callback, void *ptr) 2923290001Sglebius{ 2924290001Sglebius struct evdns_request *handle; 2925290001Sglebius struct request *req; 2926290001Sglebius log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name); 2927290001Sglebius handle = mm_calloc(1, sizeof(*handle)); 2928290001Sglebius if (handle == NULL) 2929290001Sglebius return NULL; 2930290001Sglebius EVDNS_LOCK(base); 2931290001Sglebius if (flags & DNS_QUERY_NO_SEARCH) { 2932290001Sglebius req = request_new(base, handle, TYPE_AAAA, name, flags, 2933290001Sglebius callback, ptr); 2934290001Sglebius if (req) 2935290001Sglebius request_submit(req); 2936290001Sglebius } else { 2937290001Sglebius search_request_new(base, handle, TYPE_AAAA, name, flags, 2938290001Sglebius callback, ptr); 2939290001Sglebius } 2940290001Sglebius if (handle->current_req == NULL) { 2941290001Sglebius mm_free(handle); 2942290001Sglebius handle = NULL; 2943290001Sglebius } 2944290001Sglebius EVDNS_UNLOCK(base); 2945290001Sglebius return handle; 2946290001Sglebius} 2947290001Sglebius 2948290001Sglebiusint evdns_resolve_ipv6(const char *name, int flags, 2949290001Sglebius evdns_callback_type callback, void *ptr) { 2950290001Sglebius return evdns_base_resolve_ipv6(current_base, name, flags, callback, ptr) 2951290001Sglebius ? 0 : -1; 2952290001Sglebius} 2953290001Sglebius 2954290001Sglebiusstruct evdns_request * 2955290001Sglebiusevdns_base_resolve_reverse(struct evdns_base *base, const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) { 2956290001Sglebius char buf[32]; 2957290001Sglebius struct evdns_request *handle; 2958290001Sglebius struct request *req; 2959290001Sglebius u32 a; 2960290001Sglebius EVUTIL_ASSERT(in); 2961290001Sglebius a = ntohl(in->s_addr); 2962290001Sglebius evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa", 2963290001Sglebius (int)(u8)((a )&0xff), 2964290001Sglebius (int)(u8)((a>>8 )&0xff), 2965290001Sglebius (int)(u8)((a>>16)&0xff), 2966290001Sglebius (int)(u8)((a>>24)&0xff)); 2967290001Sglebius handle = mm_calloc(1, sizeof(*handle)); 2968290001Sglebius if (handle == NULL) 2969290001Sglebius return NULL; 2970290001Sglebius log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf); 2971290001Sglebius EVDNS_LOCK(base); 2972290001Sglebius req = request_new(base, handle, TYPE_PTR, buf, flags, callback, ptr); 2973290001Sglebius if (req) 2974290001Sglebius request_submit(req); 2975290001Sglebius if (handle->current_req == NULL) { 2976290001Sglebius mm_free(handle); 2977290001Sglebius handle = NULL; 2978290001Sglebius } 2979290001Sglebius EVDNS_UNLOCK(base); 2980290001Sglebius return (handle); 2981290001Sglebius} 2982290001Sglebius 2983290001Sglebiusint evdns_resolve_reverse(const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) { 2984290001Sglebius return evdns_base_resolve_reverse(current_base, in, flags, callback, ptr) 2985290001Sglebius ? 0 : -1; 2986290001Sglebius} 2987290001Sglebius 2988290001Sglebiusstruct evdns_request * 2989290001Sglebiusevdns_base_resolve_reverse_ipv6(struct evdns_base *base, const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) { 2990290001Sglebius /* 32 nybbles, 32 periods, "ip6.arpa", NUL. */ 2991290001Sglebius char buf[73]; 2992290001Sglebius char *cp; 2993290001Sglebius struct evdns_request *handle; 2994290001Sglebius struct request *req; 2995290001Sglebius int i; 2996290001Sglebius EVUTIL_ASSERT(in); 2997290001Sglebius cp = buf; 2998290001Sglebius for (i=15; i >= 0; --i) { 2999290001Sglebius u8 byte = in->s6_addr[i]; 3000290001Sglebius *cp++ = "0123456789abcdef"[byte & 0x0f]; 3001290001Sglebius *cp++ = '.'; 3002290001Sglebius *cp++ = "0123456789abcdef"[byte >> 4]; 3003290001Sglebius *cp++ = '.'; 3004290001Sglebius } 3005290001Sglebius EVUTIL_ASSERT(cp + strlen("ip6.arpa") < buf+sizeof(buf)); 3006290001Sglebius memcpy(cp, "ip6.arpa", strlen("ip6.arpa")+1); 3007290001Sglebius handle = mm_calloc(1, sizeof(*handle)); 3008290001Sglebius if (handle == NULL) 3009290001Sglebius return NULL; 3010290001Sglebius log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf); 3011290001Sglebius EVDNS_LOCK(base); 3012290001Sglebius req = request_new(base, handle, TYPE_PTR, buf, flags, callback, ptr); 3013290001Sglebius if (req) 3014290001Sglebius request_submit(req); 3015290001Sglebius if (handle->current_req == NULL) { 3016290001Sglebius mm_free(handle); 3017290001Sglebius handle = NULL; 3018290001Sglebius } 3019290001Sglebius EVDNS_UNLOCK(base); 3020290001Sglebius return (handle); 3021290001Sglebius} 3022290001Sglebius 3023290001Sglebiusint evdns_resolve_reverse_ipv6(const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) { 3024290001Sglebius return evdns_base_resolve_reverse_ipv6(current_base, in, flags, callback, ptr) 3025290001Sglebius ? 0 : -1; 3026290001Sglebius} 3027290001Sglebius 3028290001Sglebius/* ================================================================= */ 3029290001Sglebius/* Search support */ 3030290001Sglebius/* */ 3031290001Sglebius/* the libc resolver has support for searching a number of domains */ 3032290001Sglebius/* to find a name. If nothing else then it takes the single domain */ 3033290001Sglebius/* from the gethostname() call. */ 3034290001Sglebius/* */ 3035290001Sglebius/* It can also be configured via the domain and search options in a */ 3036290001Sglebius/* resolv.conf. */ 3037290001Sglebius/* */ 3038290001Sglebius/* The ndots option controls how many dots it takes for the resolver */ 3039290001Sglebius/* to decide that a name is non-local and so try a raw lookup first. */ 3040290001Sglebius 3041290001Sglebiusstruct search_domain { 3042290001Sglebius int len; 3043290001Sglebius struct search_domain *next; 3044290001Sglebius /* the text string is appended to this structure */ 3045290001Sglebius}; 3046290001Sglebius 3047290001Sglebiusstruct search_state { 3048290001Sglebius int refcount; 3049290001Sglebius int ndots; 3050290001Sglebius int num_domains; 3051290001Sglebius struct search_domain *head; 3052290001Sglebius}; 3053290001Sglebius 3054290001Sglebiusstatic void 3055290001Sglebiussearch_state_decref(struct search_state *const state) { 3056290001Sglebius if (!state) return; 3057290001Sglebius state->refcount--; 3058290001Sglebius if (!state->refcount) { 3059290001Sglebius struct search_domain *next, *dom; 3060290001Sglebius for (dom = state->head; dom; dom = next) { 3061290001Sglebius next = dom->next; 3062290001Sglebius mm_free(dom); 3063290001Sglebius } 3064290001Sglebius mm_free(state); 3065290001Sglebius } 3066290001Sglebius} 3067290001Sglebius 3068290001Sglebiusstatic struct search_state * 3069290001Sglebiussearch_state_new(void) { 3070290001Sglebius struct search_state *state = (struct search_state *) mm_malloc(sizeof(struct search_state)); 3071290001Sglebius if (!state) return NULL; 3072290001Sglebius memset(state, 0, sizeof(struct search_state)); 3073290001Sglebius state->refcount = 1; 3074290001Sglebius state->ndots = 1; 3075290001Sglebius 3076290001Sglebius return state; 3077290001Sglebius} 3078290001Sglebius 3079290001Sglebiusstatic void 3080290001Sglebiussearch_postfix_clear(struct evdns_base *base) { 3081290001Sglebius search_state_decref(base->global_search_state); 3082290001Sglebius 3083290001Sglebius base->global_search_state = search_state_new(); 3084290001Sglebius} 3085290001Sglebius 3086290001Sglebius/* exported function */ 3087290001Sglebiusvoid 3088290001Sglebiusevdns_base_search_clear(struct evdns_base *base) 3089290001Sglebius{ 3090290001Sglebius EVDNS_LOCK(base); 3091290001Sglebius search_postfix_clear(base); 3092290001Sglebius EVDNS_UNLOCK(base); 3093290001Sglebius} 3094290001Sglebius 3095290001Sglebiusvoid 3096290001Sglebiusevdns_search_clear(void) { 3097290001Sglebius evdns_base_search_clear(current_base); 3098290001Sglebius} 3099290001Sglebius 3100290001Sglebiusstatic void 3101290001Sglebiussearch_postfix_add(struct evdns_base *base, const char *domain) { 3102290001Sglebius size_t domain_len; 3103290001Sglebius struct search_domain *sdomain; 3104290001Sglebius while (domain[0] == '.') domain++; 3105290001Sglebius domain_len = strlen(domain); 3106290001Sglebius 3107290001Sglebius ASSERT_LOCKED(base); 3108290001Sglebius if (!base->global_search_state) base->global_search_state = search_state_new(); 3109290001Sglebius if (!base->global_search_state) return; 3110290001Sglebius base->global_search_state->num_domains++; 3111290001Sglebius 3112290001Sglebius sdomain = (struct search_domain *) mm_malloc(sizeof(struct search_domain) + domain_len); 3113290001Sglebius if (!sdomain) return; 3114290001Sglebius memcpy( ((u8 *) sdomain) + sizeof(struct search_domain), domain, domain_len); 3115290001Sglebius sdomain->next = base->global_search_state->head; 3116290001Sglebius sdomain->len = (int) domain_len; 3117290001Sglebius 3118290001Sglebius base->global_search_state->head = sdomain; 3119290001Sglebius} 3120290001Sglebius 3121290001Sglebius/* reverse the order of members in the postfix list. This is needed because, */ 3122290001Sglebius/* when parsing resolv.conf we push elements in the wrong order */ 3123290001Sglebiusstatic void 3124290001Sglebiussearch_reverse(struct evdns_base *base) { 3125290001Sglebius struct search_domain *cur, *prev = NULL, *next; 3126290001Sglebius ASSERT_LOCKED(base); 3127290001Sglebius cur = base->global_search_state->head; 3128290001Sglebius while (cur) { 3129290001Sglebius next = cur->next; 3130290001Sglebius cur->next = prev; 3131290001Sglebius prev = cur; 3132290001Sglebius cur = next; 3133290001Sglebius } 3134290001Sglebius 3135290001Sglebius base->global_search_state->head = prev; 3136290001Sglebius} 3137290001Sglebius 3138290001Sglebius/* exported function */ 3139290001Sglebiusvoid 3140290001Sglebiusevdns_base_search_add(struct evdns_base *base, const char *domain) { 3141290001Sglebius EVDNS_LOCK(base); 3142290001Sglebius search_postfix_add(base, domain); 3143290001Sglebius EVDNS_UNLOCK(base); 3144290001Sglebius} 3145290001Sglebiusvoid 3146290001Sglebiusevdns_search_add(const char *domain) { 3147290001Sglebius evdns_base_search_add(current_base, domain); 3148290001Sglebius} 3149290001Sglebius 3150290001Sglebius/* exported function */ 3151290001Sglebiusvoid 3152290001Sglebiusevdns_base_search_ndots_set(struct evdns_base *base, const int ndots) { 3153290001Sglebius EVDNS_LOCK(base); 3154290001Sglebius if (!base->global_search_state) base->global_search_state = search_state_new(); 3155290001Sglebius if (base->global_search_state) 3156290001Sglebius base->global_search_state->ndots = ndots; 3157290001Sglebius EVDNS_UNLOCK(base); 3158290001Sglebius} 3159290001Sglebiusvoid 3160290001Sglebiusevdns_search_ndots_set(const int ndots) { 3161290001Sglebius evdns_base_search_ndots_set(current_base, ndots); 3162290001Sglebius} 3163290001Sglebius 3164290001Sglebiusstatic void 3165290001Sglebiussearch_set_from_hostname(struct evdns_base *base) { 3166290001Sglebius char hostname[HOST_NAME_MAX + 1], *domainname; 3167290001Sglebius 3168290001Sglebius ASSERT_LOCKED(base); 3169290001Sglebius search_postfix_clear(base); 3170290001Sglebius if (gethostname(hostname, sizeof(hostname))) return; 3171290001Sglebius domainname = strchr(hostname, '.'); 3172290001Sglebius if (!domainname) return; 3173290001Sglebius search_postfix_add(base, domainname); 3174290001Sglebius} 3175290001Sglebius 3176290001Sglebius/* warning: returns malloced string */ 3177290001Sglebiusstatic char * 3178290001Sglebiussearch_make_new(const struct search_state *const state, int n, const char *const base_name) { 3179290001Sglebius const size_t base_len = strlen(base_name); 3180290001Sglebius const char need_to_append_dot = base_name[base_len - 1] == '.' ? 0 : 1; 3181290001Sglebius struct search_domain *dom; 3182290001Sglebius 3183290001Sglebius for (dom = state->head; dom; dom = dom->next) { 3184290001Sglebius if (!n--) { 3185290001Sglebius /* this is the postfix we want */ 3186290001Sglebius /* the actual postfix string is kept at the end of the structure */ 3187290001Sglebius const u8 *const postfix = ((u8 *) dom) + sizeof(struct search_domain); 3188290001Sglebius const int postfix_len = dom->len; 3189290001Sglebius char *const newname = (char *) mm_malloc(base_len + need_to_append_dot + postfix_len + 1); 3190290001Sglebius if (!newname) return NULL; 3191290001Sglebius memcpy(newname, base_name, base_len); 3192290001Sglebius if (need_to_append_dot) newname[base_len] = '.'; 3193290001Sglebius memcpy(newname + base_len + need_to_append_dot, postfix, postfix_len); 3194290001Sglebius newname[base_len + need_to_append_dot + postfix_len] = 0; 3195290001Sglebius return newname; 3196290001Sglebius } 3197290001Sglebius } 3198290001Sglebius 3199290001Sglebius /* we ran off the end of the list and still didn't find the requested string */ 3200290001Sglebius EVUTIL_ASSERT(0); 3201290001Sglebius return NULL; /* unreachable; stops warnings in some compilers. */ 3202290001Sglebius} 3203290001Sglebius 3204290001Sglebiusstatic struct request * 3205290001Sglebiussearch_request_new(struct evdns_base *base, struct evdns_request *handle, 3206290001Sglebius int type, const char *const name, int flags, 3207290001Sglebius evdns_callback_type user_callback, void *user_arg) { 3208290001Sglebius ASSERT_LOCKED(base); 3209290001Sglebius EVUTIL_ASSERT(type == TYPE_A || type == TYPE_AAAA); 3210290001Sglebius EVUTIL_ASSERT(handle->current_req == NULL); 3211290001Sglebius if ( ((flags & DNS_QUERY_NO_SEARCH) == 0) && 3212290001Sglebius base->global_search_state && 3213290001Sglebius base->global_search_state->num_domains) { 3214290001Sglebius /* we have some domains to search */ 3215290001Sglebius struct request *req; 3216290001Sglebius if (string_num_dots(name) >= base->global_search_state->ndots) { 3217290001Sglebius req = request_new(base, handle, type, name, flags, user_callback, user_arg); 3218290001Sglebius if (!req) return NULL; 3219290001Sglebius handle->search_index = -1; 3220290001Sglebius } else { 3221290001Sglebius char *const new_name = search_make_new(base->global_search_state, 0, name); 3222290001Sglebius if (!new_name) return NULL; 3223290001Sglebius req = request_new(base, handle, type, new_name, flags, user_callback, user_arg); 3224290001Sglebius mm_free(new_name); 3225290001Sglebius if (!req) return NULL; 3226290001Sglebius handle->search_index = 0; 3227290001Sglebius } 3228290001Sglebius EVUTIL_ASSERT(handle->search_origname == NULL); 3229290001Sglebius handle->search_origname = mm_strdup(name); 3230290001Sglebius if (handle->search_origname == NULL) { 3231290001Sglebius /* XXX Should we dealloc req? If yes, how? */ 3232290001Sglebius if (req) 3233290001Sglebius mm_free(req); 3234290001Sglebius return NULL; 3235290001Sglebius } 3236290001Sglebius handle->search_state = base->global_search_state; 3237290001Sglebius handle->search_flags = flags; 3238290001Sglebius base->global_search_state->refcount++; 3239290001Sglebius request_submit(req); 3240290001Sglebius return req; 3241290001Sglebius } else { 3242290001Sglebius struct request *const req = request_new(base, handle, type, name, flags, user_callback, user_arg); 3243290001Sglebius if (!req) return NULL; 3244290001Sglebius request_submit(req); 3245290001Sglebius return req; 3246290001Sglebius } 3247290001Sglebius} 3248290001Sglebius 3249290001Sglebius/* this is called when a request has failed to find a name. We need to check */ 3250290001Sglebius/* if it is part of a search and, if so, try the next name in the list */ 3251290001Sglebius/* returns: */ 3252290001Sglebius/* 0 another request has been submitted */ 3253290001Sglebius/* 1 no more requests needed */ 3254290001Sglebiusstatic int 3255290001Sglebiussearch_try_next(struct evdns_request *const handle) { 3256290001Sglebius struct request *req = handle->current_req; 3257290001Sglebius struct evdns_base *base = req->base; 3258290001Sglebius struct request *newreq; 3259290001Sglebius ASSERT_LOCKED(base); 3260290001Sglebius if (handle->search_state) { 3261290001Sglebius /* it is part of a search */ 3262290001Sglebius char *new_name; 3263290001Sglebius handle->search_index++; 3264290001Sglebius if (handle->search_index >= handle->search_state->num_domains) { 3265290001Sglebius /* no more postfixes to try, however we may need to try */ 3266290001Sglebius /* this name without a postfix */ 3267290001Sglebius if (string_num_dots(handle->search_origname) < handle->search_state->ndots) { 3268290001Sglebius /* yep, we need to try it raw */ 3269290001Sglebius newreq = request_new(base, NULL, req->request_type, handle->search_origname, handle->search_flags, req->user_callback, req->user_pointer); 3270290001Sglebius log(EVDNS_LOG_DEBUG, "Search: trying raw query %s", handle->search_origname); 3271290001Sglebius if (newreq) { 3272290001Sglebius search_request_finished(handle); 3273290001Sglebius goto submit_next; 3274290001Sglebius } 3275290001Sglebius } 3276290001Sglebius return 1; 3277290001Sglebius } 3278290001Sglebius 3279290001Sglebius new_name = search_make_new(handle->search_state, handle->search_index, handle->search_origname); 3280290001Sglebius if (!new_name) return 1; 3281290001Sglebius log(EVDNS_LOG_DEBUG, "Search: now trying %s (%d)", new_name, handle->search_index); 3282290001Sglebius newreq = request_new(base, NULL, req->request_type, new_name, handle->search_flags, req->user_callback, req->user_pointer); 3283290001Sglebius mm_free(new_name); 3284290001Sglebius if (!newreq) return 1; 3285290001Sglebius goto submit_next; 3286290001Sglebius } 3287290001Sglebius return 1; 3288290001Sglebius 3289290001Sglebiussubmit_next: 3290290001Sglebius request_finished(req, &REQ_HEAD(req->base, req->trans_id), 0); 3291290001Sglebius handle->current_req = newreq; 3292290001Sglebius newreq->handle = handle; 3293290001Sglebius request_submit(newreq); 3294290001Sglebius return 0; 3295290001Sglebius} 3296290001Sglebius 3297290001Sglebiusstatic void 3298290001Sglebiussearch_request_finished(struct evdns_request *const handle) { 3299290001Sglebius ASSERT_LOCKED(handle->current_req->base); 3300290001Sglebius if (handle->search_state) { 3301290001Sglebius search_state_decref(handle->search_state); 3302290001Sglebius handle->search_state = NULL; 3303290001Sglebius } 3304290001Sglebius if (handle->search_origname) { 3305290001Sglebius mm_free(handle->search_origname); 3306290001Sglebius handle->search_origname = NULL; 3307290001Sglebius } 3308290001Sglebius} 3309290001Sglebius 3310290001Sglebius/* ================================================================= */ 3311290001Sglebius/* Parsing resolv.conf files */ 3312290001Sglebius 3313290001Sglebiusstatic void 3314290001Sglebiusevdns_resolv_set_defaults(struct evdns_base *base, int flags) { 3315290001Sglebius /* if the file isn't found then we assume a local resolver */ 3316290001Sglebius ASSERT_LOCKED(base); 3317290001Sglebius if (flags & DNS_OPTION_SEARCH) search_set_from_hostname(base); 3318290001Sglebius if (flags & DNS_OPTION_NAMESERVERS) evdns_base_nameserver_ip_add(base,"127.0.0.1"); 3319290001Sglebius} 3320290001Sglebius 3321290001Sglebius#ifndef EVENT__HAVE_STRTOK_R 3322290001Sglebiusstatic char * 3323290001Sglebiusstrtok_r(char *s, const char *delim, char **state) { 3324290001Sglebius char *cp, *start; 3325290001Sglebius start = cp = s ? s : *state; 3326290001Sglebius if (!cp) 3327290001Sglebius return NULL; 3328290001Sglebius while (*cp && !strchr(delim, *cp)) 3329290001Sglebius ++cp; 3330290001Sglebius if (!*cp) { 3331290001Sglebius if (cp == start) 3332290001Sglebius return NULL; 3333290001Sglebius *state = NULL; 3334290001Sglebius return start; 3335290001Sglebius } else { 3336290001Sglebius *cp++ = '\0'; 3337290001Sglebius *state = cp; 3338290001Sglebius return start; 3339290001Sglebius } 3340290001Sglebius} 3341290001Sglebius#endif 3342290001Sglebius 3343290001Sglebius/* helper version of atoi which returns -1 on error */ 3344290001Sglebiusstatic int 3345290001Sglebiusstrtoint(const char *const str) 3346290001Sglebius{ 3347290001Sglebius char *endptr; 3348290001Sglebius const int r = strtol(str, &endptr, 10); 3349290001Sglebius if (*endptr) return -1; 3350290001Sglebius return r; 3351290001Sglebius} 3352290001Sglebius 3353290001Sglebius/* Parse a number of seconds into a timeval; return -1 on error. */ 3354290001Sglebiusstatic int 3355290001Sglebiusevdns_strtotimeval(const char *const str, struct timeval *out) 3356290001Sglebius{ 3357290001Sglebius double d; 3358290001Sglebius char *endptr; 3359290001Sglebius d = strtod(str, &endptr); 3360290001Sglebius if (*endptr) return -1; 3361290001Sglebius if (d < 0) return -1; 3362290001Sglebius out->tv_sec = (int) d; 3363290001Sglebius out->tv_usec = (int) ((d - (int) d)*1000000); 3364290001Sglebius if (out->tv_sec == 0 && out->tv_usec < 1000) /* less than 1 msec */ 3365290001Sglebius return -1; 3366290001Sglebius return 0; 3367290001Sglebius} 3368290001Sglebius 3369290001Sglebius/* helper version of atoi that returns -1 on error and clips to bounds. */ 3370290001Sglebiusstatic int 3371290001Sglebiusstrtoint_clipped(const char *const str, int min, int max) 3372290001Sglebius{ 3373290001Sglebius int r = strtoint(str); 3374290001Sglebius if (r == -1) 3375290001Sglebius return r; 3376290001Sglebius else if (r<min) 3377290001Sglebius return min; 3378290001Sglebius else if (r>max) 3379290001Sglebius return max; 3380290001Sglebius else 3381290001Sglebius return r; 3382290001Sglebius} 3383290001Sglebius 3384290001Sglebiusstatic int 3385290001Sglebiusevdns_base_set_max_requests_inflight(struct evdns_base *base, int maxinflight) 3386290001Sglebius{ 3387290001Sglebius int old_n_heads = base->n_req_heads, n_heads; 3388290001Sglebius struct request **old_heads = base->req_heads, **new_heads, *req; 3389290001Sglebius int i; 3390290001Sglebius 3391290001Sglebius ASSERT_LOCKED(base); 3392290001Sglebius if (maxinflight < 1) 3393290001Sglebius maxinflight = 1; 3394290001Sglebius n_heads = (maxinflight+4) / 5; 3395290001Sglebius EVUTIL_ASSERT(n_heads > 0); 3396290001Sglebius new_heads = mm_calloc(n_heads, sizeof(struct request*)); 3397290001Sglebius if (!new_heads) 3398290001Sglebius return (-1); 3399290001Sglebius if (old_heads) { 3400290001Sglebius for (i = 0; i < old_n_heads; ++i) { 3401290001Sglebius while (old_heads[i]) { 3402290001Sglebius req = old_heads[i]; 3403290001Sglebius evdns_request_remove(req, &old_heads[i]); 3404290001Sglebius evdns_request_insert(req, &new_heads[req->trans_id % n_heads]); 3405290001Sglebius } 3406290001Sglebius } 3407290001Sglebius mm_free(old_heads); 3408290001Sglebius } 3409290001Sglebius base->req_heads = new_heads; 3410290001Sglebius base->n_req_heads = n_heads; 3411290001Sglebius base->global_max_requests_inflight = maxinflight; 3412290001Sglebius return (0); 3413290001Sglebius} 3414290001Sglebius 3415290001Sglebius/* exported function */ 3416290001Sglebiusint 3417290001Sglebiusevdns_base_set_option(struct evdns_base *base, 3418290001Sglebius const char *option, const char *val) 3419290001Sglebius{ 3420290001Sglebius int res; 3421290001Sglebius EVDNS_LOCK(base); 3422290001Sglebius res = evdns_base_set_option_impl(base, option, val, DNS_OPTIONS_ALL); 3423290001Sglebius EVDNS_UNLOCK(base); 3424290001Sglebius return res; 3425290001Sglebius} 3426290001Sglebius 3427290001Sglebiusstatic inline int 3428290001Sglebiusstr_matches_option(const char *s1, const char *optionname) 3429290001Sglebius{ 3430290001Sglebius /* Option names are given as "option:" We accept either 'option' in 3431290001Sglebius * s1, or 'option:randomjunk'. The latter form is to implement the 3432290001Sglebius * resolv.conf parser. */ 3433290001Sglebius size_t optlen = strlen(optionname); 3434290001Sglebius size_t slen = strlen(s1); 3435290001Sglebius if (slen == optlen || slen == optlen - 1) 3436290001Sglebius return !strncmp(s1, optionname, slen); 3437290001Sglebius else if (slen > optlen) 3438290001Sglebius return !strncmp(s1, optionname, optlen); 3439290001Sglebius else 3440290001Sglebius return 0; 3441290001Sglebius} 3442290001Sglebius 3443290001Sglebiusstatic int 3444290001Sglebiusevdns_base_set_option_impl(struct evdns_base *base, 3445290001Sglebius const char *option, const char *val, int flags) 3446290001Sglebius{ 3447290001Sglebius ASSERT_LOCKED(base); 3448290001Sglebius if (str_matches_option(option, "ndots:")) { 3449290001Sglebius const int ndots = strtoint(val); 3450290001Sglebius if (ndots == -1) return -1; 3451290001Sglebius if (!(flags & DNS_OPTION_SEARCH)) return 0; 3452290001Sglebius log(EVDNS_LOG_DEBUG, "Setting ndots to %d", ndots); 3453290001Sglebius if (!base->global_search_state) base->global_search_state = search_state_new(); 3454290001Sglebius if (!base->global_search_state) return -1; 3455290001Sglebius base->global_search_state->ndots = ndots; 3456290001Sglebius } else if (str_matches_option(option, "timeout:")) { 3457290001Sglebius struct timeval tv; 3458290001Sglebius if (evdns_strtotimeval(val, &tv) == -1) return -1; 3459290001Sglebius if (!(flags & DNS_OPTION_MISC)) return 0; 3460290001Sglebius log(EVDNS_LOG_DEBUG, "Setting timeout to %s", val); 3461290001Sglebius memcpy(&base->global_timeout, &tv, sizeof(struct timeval)); 3462290001Sglebius } else if (str_matches_option(option, "getaddrinfo-allow-skew:")) { 3463290001Sglebius struct timeval tv; 3464290001Sglebius if (evdns_strtotimeval(val, &tv) == -1) return -1; 3465290001Sglebius if (!(flags & DNS_OPTION_MISC)) return 0; 3466290001Sglebius log(EVDNS_LOG_DEBUG, "Setting getaddrinfo-allow-skew to %s", 3467290001Sglebius val); 3468290001Sglebius memcpy(&base->global_getaddrinfo_allow_skew, &tv, 3469290001Sglebius sizeof(struct timeval)); 3470290001Sglebius } else if (str_matches_option(option, "max-timeouts:")) { 3471290001Sglebius const int maxtimeout = strtoint_clipped(val, 1, 255); 3472290001Sglebius if (maxtimeout == -1) return -1; 3473290001Sglebius if (!(flags & DNS_OPTION_MISC)) return 0; 3474290001Sglebius log(EVDNS_LOG_DEBUG, "Setting maximum allowed timeouts to %d", 3475290001Sglebius maxtimeout); 3476290001Sglebius base->global_max_nameserver_timeout = maxtimeout; 3477290001Sglebius } else if (str_matches_option(option, "max-inflight:")) { 3478290001Sglebius const int maxinflight = strtoint_clipped(val, 1, 65000); 3479290001Sglebius if (maxinflight == -1) return -1; 3480290001Sglebius if (!(flags & DNS_OPTION_MISC)) return 0; 3481290001Sglebius log(EVDNS_LOG_DEBUG, "Setting maximum inflight requests to %d", 3482290001Sglebius maxinflight); 3483290001Sglebius evdns_base_set_max_requests_inflight(base, maxinflight); 3484290001Sglebius } else if (str_matches_option(option, "attempts:")) { 3485290001Sglebius int retries = strtoint(val); 3486290001Sglebius if (retries == -1) return -1; 3487290001Sglebius if (retries > 255) retries = 255; 3488290001Sglebius if (!(flags & DNS_OPTION_MISC)) return 0; 3489290001Sglebius log(EVDNS_LOG_DEBUG, "Setting retries to %d", retries); 3490290001Sglebius base->global_max_retransmits = retries; 3491290001Sglebius } else if (str_matches_option(option, "randomize-case:")) { 3492290001Sglebius int randcase = strtoint(val); 3493290001Sglebius if (!(flags & DNS_OPTION_MISC)) return 0; 3494290001Sglebius base->global_randomize_case = randcase; 3495290001Sglebius } else if (str_matches_option(option, "bind-to:")) { 3496290001Sglebius /* XXX This only applies to successive nameservers, not 3497290001Sglebius * to already-configured ones. We might want to fix that. */ 3498290001Sglebius int len = sizeof(base->global_outgoing_address); 3499290001Sglebius if (!(flags & DNS_OPTION_NAMESERVERS)) return 0; 3500290001Sglebius if (evutil_parse_sockaddr_port(val, 3501290001Sglebius (struct sockaddr*)&base->global_outgoing_address, &len)) 3502290001Sglebius return -1; 3503290001Sglebius base->global_outgoing_addrlen = len; 3504290001Sglebius } else if (str_matches_option(option, "initial-probe-timeout:")) { 3505290001Sglebius struct timeval tv; 3506290001Sglebius if (evdns_strtotimeval(val, &tv) == -1) return -1; 3507290001Sglebius if (tv.tv_sec > 3600) 3508290001Sglebius tv.tv_sec = 3600; 3509290001Sglebius if (!(flags & DNS_OPTION_MISC)) return 0; 3510290001Sglebius log(EVDNS_LOG_DEBUG, "Setting initial probe timeout to %s", 3511290001Sglebius val); 3512290001Sglebius memcpy(&base->global_nameserver_probe_initial_timeout, &tv, 3513290001Sglebius sizeof(tv)); 3514290001Sglebius } 3515290001Sglebius return 0; 3516290001Sglebius} 3517290001Sglebius 3518290001Sglebiusint 3519290001Sglebiusevdns_set_option(const char *option, const char *val, int flags) 3520290001Sglebius{ 3521290001Sglebius if (!current_base) 3522290001Sglebius current_base = evdns_base_new(NULL, 0); 3523290001Sglebius return evdns_base_set_option(current_base, option, val); 3524290001Sglebius} 3525290001Sglebius 3526290001Sglebiusstatic void 3527290001Sglebiusresolv_conf_parse_line(struct evdns_base *base, char *const start, int flags) { 3528290001Sglebius char *strtok_state; 3529290001Sglebius static const char *const delims = " \t"; 3530290001Sglebius#define NEXT_TOKEN strtok_r(NULL, delims, &strtok_state) 3531290001Sglebius 3532290001Sglebius 3533290001Sglebius char *const first_token = strtok_r(start, delims, &strtok_state); 3534290001Sglebius ASSERT_LOCKED(base); 3535290001Sglebius if (!first_token) return; 3536290001Sglebius 3537290001Sglebius if (!strcmp(first_token, "nameserver") && (flags & DNS_OPTION_NAMESERVERS)) { 3538290001Sglebius const char *const nameserver = NEXT_TOKEN; 3539290001Sglebius 3540290001Sglebius if (nameserver) 3541290001Sglebius evdns_base_nameserver_ip_add(base, nameserver); 3542290001Sglebius } else if (!strcmp(first_token, "domain") && (flags & DNS_OPTION_SEARCH)) { 3543290001Sglebius const char *const domain = NEXT_TOKEN; 3544290001Sglebius if (domain) { 3545290001Sglebius search_postfix_clear(base); 3546290001Sglebius search_postfix_add(base, domain); 3547290001Sglebius } 3548290001Sglebius } else if (!strcmp(first_token, "search") && (flags & DNS_OPTION_SEARCH)) { 3549290001Sglebius const char *domain; 3550290001Sglebius search_postfix_clear(base); 3551290001Sglebius 3552290001Sglebius while ((domain = NEXT_TOKEN)) { 3553290001Sglebius search_postfix_add(base, domain); 3554290001Sglebius } 3555290001Sglebius search_reverse(base); 3556290001Sglebius } else if (!strcmp(first_token, "options")) { 3557290001Sglebius const char *option; 3558290001Sglebius while ((option = NEXT_TOKEN)) { 3559290001Sglebius const char *val = strchr(option, ':'); 3560290001Sglebius evdns_base_set_option_impl(base, option, val ? val+1 : "", flags); 3561290001Sglebius } 3562290001Sglebius } 3563290001Sglebius#undef NEXT_TOKEN 3564290001Sglebius} 3565290001Sglebius 3566290001Sglebius/* exported function */ 3567290001Sglebius/* returns: */ 3568290001Sglebius/* 0 no errors */ 3569290001Sglebius/* 1 failed to open file */ 3570290001Sglebius/* 2 failed to stat file */ 3571290001Sglebius/* 3 file too large */ 3572290001Sglebius/* 4 out of memory */ 3573290001Sglebius/* 5 short read from file */ 3574290001Sglebiusint 3575290001Sglebiusevdns_base_resolv_conf_parse(struct evdns_base *base, int flags, const char *const filename) { 3576290001Sglebius int res; 3577290001Sglebius EVDNS_LOCK(base); 3578290001Sglebius res = evdns_base_resolv_conf_parse_impl(base, flags, filename); 3579290001Sglebius EVDNS_UNLOCK(base); 3580290001Sglebius return res; 3581290001Sglebius} 3582290001Sglebius 3583290001Sglebiusstatic char * 3584290001Sglebiusevdns_get_default_hosts_filename(void) 3585290001Sglebius{ 3586290001Sglebius#ifdef _WIN32 3587290001Sglebius /* Windows is a little coy about where it puts its configuration 3588290001Sglebius * files. Sure, they're _usually_ in C:\windows\system32, but 3589290001Sglebius * there's no reason in principle they couldn't be in 3590290001Sglebius * W:\hoboken chicken emergency\ 3591290001Sglebius */ 3592290001Sglebius char path[MAX_PATH+1]; 3593290001Sglebius static const char hostfile[] = "\\drivers\\etc\\hosts"; 3594290001Sglebius char *path_out; 3595290001Sglebius size_t len_out; 3596290001Sglebius 3597290001Sglebius if (! SHGetSpecialFolderPathA(NULL, path, CSIDL_SYSTEM, 0)) 3598290001Sglebius return NULL; 3599290001Sglebius len_out = strlen(path)+strlen(hostfile)+1; 3600290001Sglebius path_out = mm_malloc(len_out); 3601290001Sglebius evutil_snprintf(path_out, len_out, "%s%s", path, hostfile); 3602290001Sglebius return path_out; 3603290001Sglebius#else 3604290001Sglebius return mm_strdup("/etc/hosts"); 3605290001Sglebius#endif 3606290001Sglebius} 3607290001Sglebius 3608290001Sglebiusstatic int 3609290001Sglebiusevdns_base_resolv_conf_parse_impl(struct evdns_base *base, int flags, const char *const filename) { 3610290001Sglebius size_t n; 3611290001Sglebius char *resolv; 3612290001Sglebius char *start; 3613290001Sglebius int err = 0; 3614290001Sglebius 3615290001Sglebius log(EVDNS_LOG_DEBUG, "Parsing resolv.conf file %s", filename); 3616290001Sglebius 3617290001Sglebius if (flags & DNS_OPTION_HOSTSFILE) { 3618290001Sglebius char *fname = evdns_get_default_hosts_filename(); 3619290001Sglebius evdns_base_load_hosts(base, fname); 3620290001Sglebius if (fname) 3621290001Sglebius mm_free(fname); 3622290001Sglebius } 3623290001Sglebius 3624290001Sglebius if ((err = evutil_read_file_(filename, &resolv, &n, 0)) < 0) { 3625290001Sglebius if (err == -1) { 3626290001Sglebius /* No file. */ 3627290001Sglebius evdns_resolv_set_defaults(base, flags); 3628290001Sglebius return 1; 3629290001Sglebius } else { 3630290001Sglebius return 2; 3631290001Sglebius } 3632290001Sglebius } 3633290001Sglebius 3634290001Sglebius start = resolv; 3635290001Sglebius for (;;) { 3636290001Sglebius char *const newline = strchr(start, '\n'); 3637290001Sglebius if (!newline) { 3638290001Sglebius resolv_conf_parse_line(base, start, flags); 3639290001Sglebius break; 3640290001Sglebius } else { 3641290001Sglebius *newline = 0; 3642290001Sglebius resolv_conf_parse_line(base, start, flags); 3643290001Sglebius start = newline + 1; 3644290001Sglebius } 3645290001Sglebius } 3646290001Sglebius 3647290001Sglebius if (!base->server_head && (flags & DNS_OPTION_NAMESERVERS)) { 3648290001Sglebius /* no nameservers were configured. */ 3649290001Sglebius evdns_base_nameserver_ip_add(base, "127.0.0.1"); 3650290001Sglebius err = 6; 3651290001Sglebius } 3652290001Sglebius if (flags & DNS_OPTION_SEARCH && (!base->global_search_state || base->global_search_state->num_domains == 0)) { 3653290001Sglebius search_set_from_hostname(base); 3654290001Sglebius } 3655290001Sglebius 3656290001Sglebius mm_free(resolv); 3657290001Sglebius return err; 3658290001Sglebius} 3659290001Sglebius 3660290001Sglebiusint 3661290001Sglebiusevdns_resolv_conf_parse(int flags, const char *const filename) { 3662290001Sglebius if (!current_base) 3663290001Sglebius current_base = evdns_base_new(NULL, 0); 3664290001Sglebius return evdns_base_resolv_conf_parse(current_base, flags, filename); 3665290001Sglebius} 3666290001Sglebius 3667290001Sglebius 3668290001Sglebius#ifdef _WIN32 3669290001Sglebius/* Add multiple nameservers from a space-or-comma-separated list. */ 3670290001Sglebiusstatic int 3671290001Sglebiusevdns_nameserver_ip_add_line(struct evdns_base *base, const char *ips) { 3672290001Sglebius const char *addr; 3673290001Sglebius char *buf; 3674290001Sglebius int r; 3675290001Sglebius ASSERT_LOCKED(base); 3676290001Sglebius while (*ips) { 3677290001Sglebius while (isspace(*ips) || *ips == ',' || *ips == '\t') 3678290001Sglebius ++ips; 3679290001Sglebius addr = ips; 3680290001Sglebius while (isdigit(*ips) || *ips == '.' || *ips == ':' || 3681290001Sglebius *ips=='[' || *ips==']') 3682290001Sglebius ++ips; 3683290001Sglebius buf = mm_malloc(ips-addr+1); 3684290001Sglebius if (!buf) return 4; 3685290001Sglebius memcpy(buf, addr, ips-addr); 3686290001Sglebius buf[ips-addr] = '\0'; 3687290001Sglebius r = evdns_base_nameserver_ip_add(base, buf); 3688290001Sglebius mm_free(buf); 3689290001Sglebius if (r) return r; 3690290001Sglebius } 3691290001Sglebius return 0; 3692290001Sglebius} 3693290001Sglebius 3694290001Sglebiustypedef DWORD(WINAPI *GetNetworkParams_fn_t)(FIXED_INFO *, DWORD*); 3695290001Sglebius 3696290001Sglebius/* Use the windows GetNetworkParams interface in iphlpapi.dll to */ 3697290001Sglebius/* figure out what our nameservers are. */ 3698290001Sglebiusstatic int 3699290001Sglebiusload_nameservers_with_getnetworkparams(struct evdns_base *base) 3700290001Sglebius{ 3701290001Sglebius /* Based on MSDN examples and inspection of c-ares code. */ 3702290001Sglebius FIXED_INFO *fixed; 3703290001Sglebius HMODULE handle = 0; 3704290001Sglebius ULONG size = sizeof(FIXED_INFO); 3705290001Sglebius void *buf = NULL; 3706290001Sglebius int status = 0, r, added_any; 3707290001Sglebius IP_ADDR_STRING *ns; 3708290001Sglebius GetNetworkParams_fn_t fn; 3709290001Sglebius 3710290001Sglebius ASSERT_LOCKED(base); 3711290001Sglebius if (!(handle = evutil_load_windows_system_library_( 3712290001Sglebius TEXT("iphlpapi.dll")))) { 3713290001Sglebius log(EVDNS_LOG_WARN, "Could not open iphlpapi.dll"); 3714290001Sglebius status = -1; 3715290001Sglebius goto done; 3716290001Sglebius } 3717290001Sglebius if (!(fn = (GetNetworkParams_fn_t) GetProcAddress(handle, "GetNetworkParams"))) { 3718290001Sglebius log(EVDNS_LOG_WARN, "Could not get address of function."); 3719290001Sglebius status = -1; 3720290001Sglebius goto done; 3721290001Sglebius } 3722290001Sglebius 3723290001Sglebius buf = mm_malloc(size); 3724290001Sglebius if (!buf) { status = 4; goto done; } 3725290001Sglebius fixed = buf; 3726290001Sglebius r = fn(fixed, &size); 3727290001Sglebius if (r != ERROR_SUCCESS && r != ERROR_BUFFER_OVERFLOW) { 3728290001Sglebius status = -1; 3729290001Sglebius goto done; 3730290001Sglebius } 3731290001Sglebius if (r != ERROR_SUCCESS) { 3732290001Sglebius mm_free(buf); 3733290001Sglebius buf = mm_malloc(size); 3734290001Sglebius if (!buf) { status = 4; goto done; } 3735290001Sglebius fixed = buf; 3736290001Sglebius r = fn(fixed, &size); 3737290001Sglebius if (r != ERROR_SUCCESS) { 3738290001Sglebius log(EVDNS_LOG_DEBUG, "fn() failed."); 3739290001Sglebius status = -1; 3740290001Sglebius goto done; 3741290001Sglebius } 3742290001Sglebius } 3743290001Sglebius 3744290001Sglebius EVUTIL_ASSERT(fixed); 3745290001Sglebius added_any = 0; 3746290001Sglebius ns = &(fixed->DnsServerList); 3747290001Sglebius while (ns) { 3748290001Sglebius r = evdns_nameserver_ip_add_line(base, ns->IpAddress.String); 3749290001Sglebius if (r) { 3750290001Sglebius log(EVDNS_LOG_DEBUG,"Could not add nameserver %s to list,error: %d", 3751290001Sglebius (ns->IpAddress.String),(int)GetLastError()); 3752290001Sglebius status = r; 3753290001Sglebius } else { 3754290001Sglebius ++added_any; 3755290001Sglebius log(EVDNS_LOG_DEBUG,"Successfully added %s as nameserver",ns->IpAddress.String); 3756290001Sglebius } 3757290001Sglebius 3758290001Sglebius ns = ns->Next; 3759290001Sglebius } 3760290001Sglebius 3761290001Sglebius if (!added_any) { 3762290001Sglebius log(EVDNS_LOG_DEBUG, "No nameservers added."); 3763290001Sglebius if (status == 0) 3764290001Sglebius status = -1; 3765290001Sglebius } else { 3766290001Sglebius status = 0; 3767290001Sglebius } 3768290001Sglebius 3769290001Sglebius done: 3770290001Sglebius if (buf) 3771290001Sglebius mm_free(buf); 3772290001Sglebius if (handle) 3773290001Sglebius FreeLibrary(handle); 3774290001Sglebius return status; 3775290001Sglebius} 3776290001Sglebius 3777290001Sglebiusstatic int 3778290001Sglebiusconfig_nameserver_from_reg_key(struct evdns_base *base, HKEY key, const TCHAR *subkey) 3779290001Sglebius{ 3780290001Sglebius char *buf; 3781290001Sglebius DWORD bufsz = 0, type = 0; 3782290001Sglebius int status = 0; 3783290001Sglebius 3784290001Sglebius ASSERT_LOCKED(base); 3785290001Sglebius if (RegQueryValueEx(key, subkey, 0, &type, NULL, &bufsz) 3786290001Sglebius != ERROR_MORE_DATA) 3787290001Sglebius return -1; 3788290001Sglebius if (!(buf = mm_malloc(bufsz))) 3789290001Sglebius return -1; 3790290001Sglebius 3791290001Sglebius if (RegQueryValueEx(key, subkey, 0, &type, (LPBYTE)buf, &bufsz) 3792290001Sglebius == ERROR_SUCCESS && bufsz > 1) { 3793290001Sglebius status = evdns_nameserver_ip_add_line(base,buf); 3794290001Sglebius } 3795290001Sglebius 3796290001Sglebius mm_free(buf); 3797290001Sglebius return status; 3798290001Sglebius} 3799290001Sglebius 3800290001Sglebius#define SERVICES_KEY TEXT("System\\CurrentControlSet\\Services\\") 3801290001Sglebius#define WIN_NS_9X_KEY SERVICES_KEY TEXT("VxD\\MSTCP") 3802290001Sglebius#define WIN_NS_NT_KEY SERVICES_KEY TEXT("Tcpip\\Parameters") 3803290001Sglebius 3804290001Sglebiusstatic int 3805290001Sglebiusload_nameservers_from_registry(struct evdns_base *base) 3806290001Sglebius{ 3807290001Sglebius int found = 0; 3808290001Sglebius int r; 3809290001Sglebius#define TRY(k, name) \ 3810290001Sglebius if (!found && config_nameserver_from_reg_key(base,k,TEXT(name)) == 0) { \ 3811290001Sglebius log(EVDNS_LOG_DEBUG,"Found nameservers in %s/%s",#k,name); \ 3812290001Sglebius found = 1; \ 3813290001Sglebius } else if (!found) { \ 3814290001Sglebius log(EVDNS_LOG_DEBUG,"Didn't find nameservers in %s/%s", \ 3815290001Sglebius #k,#name); \ 3816290001Sglebius } 3817290001Sglebius 3818290001Sglebius ASSERT_LOCKED(base); 3819290001Sglebius 3820290001Sglebius if (((int)GetVersion()) > 0) { /* NT */ 3821290001Sglebius HKEY nt_key = 0, interfaces_key = 0; 3822290001Sglebius 3823290001Sglebius if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, 3824290001Sglebius KEY_READ, &nt_key) != ERROR_SUCCESS) { 3825290001Sglebius log(EVDNS_LOG_DEBUG,"Couldn't open nt key, %d",(int)GetLastError()); 3826290001Sglebius return -1; 3827290001Sglebius } 3828290001Sglebius r = RegOpenKeyEx(nt_key, TEXT("Interfaces"), 0, 3829290001Sglebius KEY_QUERY_VALUE|KEY_ENUMERATE_SUB_KEYS, 3830290001Sglebius &interfaces_key); 3831290001Sglebius if (r != ERROR_SUCCESS) { 3832290001Sglebius log(EVDNS_LOG_DEBUG,"Couldn't open interfaces key, %d",(int)GetLastError()); 3833290001Sglebius return -1; 3834290001Sglebius } 3835290001Sglebius TRY(nt_key, "NameServer"); 3836290001Sglebius TRY(nt_key, "DhcpNameServer"); 3837290001Sglebius TRY(interfaces_key, "NameServer"); 3838290001Sglebius TRY(interfaces_key, "DhcpNameServer"); 3839290001Sglebius RegCloseKey(interfaces_key); 3840290001Sglebius RegCloseKey(nt_key); 3841290001Sglebius } else { 3842290001Sglebius HKEY win_key = 0; 3843290001Sglebius if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_9X_KEY, 0, 3844290001Sglebius KEY_READ, &win_key) != ERROR_SUCCESS) { 3845290001Sglebius log(EVDNS_LOG_DEBUG, "Couldn't open registry key, %d", (int)GetLastError()); 3846290001Sglebius return -1; 3847290001Sglebius } 3848290001Sglebius TRY(win_key, "NameServer"); 3849290001Sglebius RegCloseKey(win_key); 3850290001Sglebius } 3851290001Sglebius 3852290001Sglebius if (found == 0) { 3853290001Sglebius log(EVDNS_LOG_WARN,"Didn't find any nameservers."); 3854290001Sglebius } 3855290001Sglebius 3856290001Sglebius return found ? 0 : -1; 3857290001Sglebius#undef TRY 3858290001Sglebius} 3859290001Sglebius 3860290001Sglebiusint 3861290001Sglebiusevdns_base_config_windows_nameservers(struct evdns_base *base) 3862290001Sglebius{ 3863290001Sglebius int r; 3864290001Sglebius char *fname; 3865290001Sglebius if (base == NULL) 3866290001Sglebius base = current_base; 3867290001Sglebius if (base == NULL) 3868290001Sglebius return -1; 3869290001Sglebius EVDNS_LOCK(base); 3870290001Sglebius fname = evdns_get_default_hosts_filename(); 3871290001Sglebius log(EVDNS_LOG_DEBUG, "Loading hosts entries from %s", fname); 3872290001Sglebius evdns_base_load_hosts(base, fname); 3873290001Sglebius if (fname) 3874290001Sglebius mm_free(fname); 3875290001Sglebius 3876290001Sglebius if (load_nameservers_with_getnetworkparams(base) == 0) { 3877290001Sglebius EVDNS_UNLOCK(base); 3878290001Sglebius return 0; 3879290001Sglebius } 3880290001Sglebius r = load_nameservers_from_registry(base); 3881290001Sglebius 3882290001Sglebius EVDNS_UNLOCK(base); 3883290001Sglebius return r; 3884290001Sglebius} 3885290001Sglebius 3886290001Sglebiusint 3887290001Sglebiusevdns_config_windows_nameservers(void) 3888290001Sglebius{ 3889290001Sglebius if (!current_base) { 3890290001Sglebius current_base = evdns_base_new(NULL, 1); 3891290001Sglebius return current_base == NULL ? -1 : 0; 3892290001Sglebius } else { 3893290001Sglebius return evdns_base_config_windows_nameservers(current_base); 3894290001Sglebius } 3895290001Sglebius} 3896290001Sglebius#endif 3897290001Sglebius 3898290001Sglebiusstruct evdns_base * 3899290001Sglebiusevdns_base_new(struct event_base *event_base, int flags) 3900290001Sglebius{ 3901290001Sglebius struct evdns_base *base; 3902290001Sglebius 3903290001Sglebius if (evutil_secure_rng_init() < 0) { 3904290001Sglebius log(EVDNS_LOG_WARN, "Unable to seed random number generator; " 3905290001Sglebius "DNS can't run."); 3906290001Sglebius return NULL; 3907290001Sglebius } 3908290001Sglebius 3909290001Sglebius /* Give the evutil library a hook into its evdns-enabled 3910290001Sglebius * functionality. We can't just call evdns_getaddrinfo directly or 3911290001Sglebius * else libevent-core will depend on libevent-extras. */ 3912290001Sglebius evutil_set_evdns_getaddrinfo_fn_(evdns_getaddrinfo); 3913290001Sglebius 3914290001Sglebius base = mm_malloc(sizeof(struct evdns_base)); 3915290001Sglebius if (base == NULL) 3916290001Sglebius return (NULL); 3917290001Sglebius memset(base, 0, sizeof(struct evdns_base)); 3918290001Sglebius base->req_waiting_head = NULL; 3919290001Sglebius 3920290001Sglebius EVTHREAD_ALLOC_LOCK(base->lock, EVTHREAD_LOCKTYPE_RECURSIVE); 3921290001Sglebius EVDNS_LOCK(base); 3922290001Sglebius 3923290001Sglebius /* Set max requests inflight and allocate req_heads. */ 3924290001Sglebius base->req_heads = NULL; 3925290001Sglebius 3926290001Sglebius evdns_base_set_max_requests_inflight(base, 64); 3927290001Sglebius 3928290001Sglebius base->server_head = NULL; 3929290001Sglebius base->event_base = event_base; 3930290001Sglebius base->global_good_nameservers = base->global_requests_inflight = 3931290001Sglebius base->global_requests_waiting = 0; 3932290001Sglebius 3933290001Sglebius base->global_timeout.tv_sec = 5; 3934290001Sglebius base->global_timeout.tv_usec = 0; 3935290001Sglebius base->global_max_reissues = 1; 3936290001Sglebius base->global_max_retransmits = 3; 3937290001Sglebius base->global_max_nameserver_timeout = 3; 3938290001Sglebius base->global_search_state = NULL; 3939290001Sglebius base->global_randomize_case = 1; 3940290001Sglebius base->global_getaddrinfo_allow_skew.tv_sec = 3; 3941290001Sglebius base->global_getaddrinfo_allow_skew.tv_usec = 0; 3942290001Sglebius base->global_nameserver_probe_initial_timeout.tv_sec = 10; 3943290001Sglebius base->global_nameserver_probe_initial_timeout.tv_usec = 0; 3944290001Sglebius 3945290001Sglebius TAILQ_INIT(&base->hostsdb); 3946290001Sglebius 3947290001Sglebius#define EVDNS_BASE_ALL_FLAGS (0x8001) 3948290001Sglebius if (flags & ~EVDNS_BASE_ALL_FLAGS) { 3949290001Sglebius flags = EVDNS_BASE_INITIALIZE_NAMESERVERS; 3950290001Sglebius log(EVDNS_LOG_WARN, 3951290001Sglebius "Unrecognized flag passed to evdns_base_new(). Assuming " 3952290001Sglebius "you meant EVDNS_BASE_INITIALIZE_NAMESERVERS."); 3953290001Sglebius } 3954290001Sglebius#undef EVDNS_BASE_ALL_FLAGS 3955290001Sglebius 3956290001Sglebius if (flags & EVDNS_BASE_INITIALIZE_NAMESERVERS) { 3957290001Sglebius int r; 3958290001Sglebius#ifdef _WIN32 3959290001Sglebius r = evdns_base_config_windows_nameservers(base); 3960290001Sglebius#else 3961290001Sglebius r = evdns_base_resolv_conf_parse(base, DNS_OPTIONS_ALL, "/etc/resolv.conf"); 3962290001Sglebius#endif 3963290001Sglebius if (r == -1) { 3964290001Sglebius evdns_base_free_and_unlock(base, 0); 3965290001Sglebius return NULL; 3966290001Sglebius } 3967290001Sglebius } 3968290001Sglebius if (flags & EVDNS_BASE_DISABLE_WHEN_INACTIVE) { 3969290001Sglebius base->disable_when_inactive = 1; 3970290001Sglebius } 3971290001Sglebius 3972290001Sglebius EVDNS_UNLOCK(base); 3973290001Sglebius return base; 3974290001Sglebius} 3975290001Sglebius 3976290001Sglebiusint 3977290001Sglebiusevdns_init(void) 3978290001Sglebius{ 3979290001Sglebius struct evdns_base *base = evdns_base_new(NULL, 1); 3980290001Sglebius if (base) { 3981290001Sglebius current_base = base; 3982290001Sglebius return 0; 3983290001Sglebius } else { 3984290001Sglebius return -1; 3985290001Sglebius } 3986290001Sglebius} 3987290001Sglebius 3988290001Sglebiusconst char * 3989290001Sglebiusevdns_err_to_string(int err) 3990290001Sglebius{ 3991290001Sglebius switch (err) { 3992290001Sglebius case DNS_ERR_NONE: return "no error"; 3993290001Sglebius case DNS_ERR_FORMAT: return "misformatted query"; 3994290001Sglebius case DNS_ERR_SERVERFAILED: return "server failed"; 3995290001Sglebius case DNS_ERR_NOTEXIST: return "name does not exist"; 3996290001Sglebius case DNS_ERR_NOTIMPL: return "query not implemented"; 3997290001Sglebius case DNS_ERR_REFUSED: return "refused"; 3998290001Sglebius 3999290001Sglebius case DNS_ERR_TRUNCATED: return "reply truncated or ill-formed"; 4000290001Sglebius case DNS_ERR_UNKNOWN: return "unknown"; 4001290001Sglebius case DNS_ERR_TIMEOUT: return "request timed out"; 4002290001Sglebius case DNS_ERR_SHUTDOWN: return "dns subsystem shut down"; 4003290001Sglebius case DNS_ERR_CANCEL: return "dns request canceled"; 4004290001Sglebius case DNS_ERR_NODATA: return "no records in the reply"; 4005290001Sglebius default: return "[Unknown error code]"; 4006290001Sglebius } 4007290001Sglebius} 4008290001Sglebius 4009290001Sglebiusstatic void 4010290001Sglebiusevdns_nameserver_free(struct nameserver *server) 4011290001Sglebius{ 4012290001Sglebius if (server->socket >= 0) 4013290001Sglebius evutil_closesocket(server->socket); 4014290001Sglebius (void) event_del(&server->event); 4015290001Sglebius event_debug_unassign(&server->event); 4016290001Sglebius if (server->state == 0) 4017290001Sglebius (void) event_del(&server->timeout_event); 4018290001Sglebius if (server->probe_request) { 4019290001Sglebius evdns_cancel_request(server->base, server->probe_request); 4020290001Sglebius server->probe_request = NULL; 4021290001Sglebius } 4022290001Sglebius event_debug_unassign(&server->timeout_event); 4023290001Sglebius mm_free(server); 4024290001Sglebius} 4025290001Sglebius 4026290001Sglebiusstatic void 4027290001Sglebiusevdns_base_free_and_unlock(struct evdns_base *base, int fail_requests) 4028290001Sglebius{ 4029290001Sglebius struct nameserver *server, *server_next; 4030290001Sglebius struct search_domain *dom, *dom_next; 4031290001Sglebius int i; 4032290001Sglebius 4033290001Sglebius /* Requires that we hold the lock. */ 4034290001Sglebius 4035290001Sglebius /* TODO(nickm) we might need to refcount here. */ 4036290001Sglebius 4037290001Sglebius for (server = base->server_head; server; server = server_next) { 4038290001Sglebius server_next = server->next; 4039290001Sglebius evdns_nameserver_free(server); 4040290001Sglebius if (server_next == base->server_head) 4041290001Sglebius break; 4042290001Sglebius } 4043290001Sglebius base->server_head = NULL; 4044290001Sglebius base->global_good_nameservers = 0; 4045290001Sglebius 4046290001Sglebius for (i = 0; i < base->n_req_heads; ++i) { 4047290001Sglebius while (base->req_heads[i]) { 4048290001Sglebius if (fail_requests) 4049290001Sglebius reply_schedule_callback(base->req_heads[i], 0, DNS_ERR_SHUTDOWN, NULL); 4050290001Sglebius request_finished(base->req_heads[i], &REQ_HEAD(base, base->req_heads[i]->trans_id), 1); 4051290001Sglebius } 4052290001Sglebius } 4053290001Sglebius while (base->req_waiting_head) { 4054290001Sglebius if (fail_requests) 4055290001Sglebius reply_schedule_callback(base->req_waiting_head, 0, DNS_ERR_SHUTDOWN, NULL); 4056290001Sglebius request_finished(base->req_waiting_head, &base->req_waiting_head, 1); 4057290001Sglebius } 4058290001Sglebius base->global_requests_inflight = base->global_requests_waiting = 0; 4059290001Sglebius 4060290001Sglebius 4061290001Sglebius if (base->global_search_state) { 4062290001Sglebius for (dom = base->global_search_state->head; dom; dom = dom_next) { 4063290001Sglebius dom_next = dom->next; 4064290001Sglebius mm_free(dom); 4065290001Sglebius } 4066290001Sglebius mm_free(base->global_search_state); 4067290001Sglebius base->global_search_state = NULL; 4068290001Sglebius } 4069290001Sglebius 4070290001Sglebius { 4071290001Sglebius struct hosts_entry *victim; 4072290001Sglebius while ((victim = TAILQ_FIRST(&base->hostsdb))) { 4073290001Sglebius TAILQ_REMOVE(&base->hostsdb, victim, next); 4074290001Sglebius mm_free(victim); 4075290001Sglebius } 4076290001Sglebius } 4077290001Sglebius 4078290001Sglebius mm_free(base->req_heads); 4079290001Sglebius 4080290001Sglebius EVDNS_UNLOCK(base); 4081290001Sglebius EVTHREAD_FREE_LOCK(base->lock, EVTHREAD_LOCKTYPE_RECURSIVE); 4082290001Sglebius 4083290001Sglebius mm_free(base); 4084290001Sglebius} 4085290001Sglebius 4086290001Sglebiusvoid 4087290001Sglebiusevdns_base_free(struct evdns_base *base, int fail_requests) 4088290001Sglebius{ 4089290001Sglebius EVDNS_LOCK(base); 4090290001Sglebius evdns_base_free_and_unlock(base, fail_requests); 4091290001Sglebius} 4092290001Sglebius 4093290001Sglebiusvoid 4094290001Sglebiusevdns_base_clear_host_addresses(struct evdns_base *base) 4095290001Sglebius{ 4096290001Sglebius struct hosts_entry *victim; 4097290001Sglebius EVDNS_LOCK(base); 4098290001Sglebius while ((victim = TAILQ_FIRST(&base->hostsdb))) { 4099290001Sglebius TAILQ_REMOVE(&base->hostsdb, victim, next); 4100290001Sglebius mm_free(victim); 4101290001Sglebius } 4102290001Sglebius EVDNS_UNLOCK(base); 4103290001Sglebius} 4104290001Sglebius 4105290001Sglebiusvoid 4106290001Sglebiusevdns_shutdown(int fail_requests) 4107290001Sglebius{ 4108290001Sglebius if (current_base) { 4109290001Sglebius struct evdns_base *b = current_base; 4110290001Sglebius current_base = NULL; 4111290001Sglebius evdns_base_free(b, fail_requests); 4112290001Sglebius } 4113290001Sglebius evdns_log_fn = NULL; 4114290001Sglebius} 4115290001Sglebius 4116290001Sglebiusstatic int 4117290001Sglebiusevdns_base_parse_hosts_line(struct evdns_base *base, char *line) 4118290001Sglebius{ 4119290001Sglebius char *strtok_state; 4120290001Sglebius static const char *const delims = " \t"; 4121290001Sglebius char *const addr = strtok_r(line, delims, &strtok_state); 4122290001Sglebius char *hostname, *hash; 4123290001Sglebius struct sockaddr_storage ss; 4124290001Sglebius int socklen = sizeof(ss); 4125290001Sglebius ASSERT_LOCKED(base); 4126290001Sglebius 4127290001Sglebius#define NEXT_TOKEN strtok_r(NULL, delims, &strtok_state) 4128290001Sglebius 4129290001Sglebius if (!addr || *addr == '#') 4130290001Sglebius return 0; 4131290001Sglebius 4132290001Sglebius memset(&ss, 0, sizeof(ss)); 4133290001Sglebius if (evutil_parse_sockaddr_port(addr, (struct sockaddr*)&ss, &socklen)<0) 4134290001Sglebius return -1; 4135290001Sglebius if (socklen > (int)sizeof(struct sockaddr_in6)) 4136290001Sglebius return -1; 4137290001Sglebius 4138290001Sglebius if (sockaddr_getport((struct sockaddr*)&ss)) 4139290001Sglebius return -1; 4140290001Sglebius 4141290001Sglebius while ((hostname = NEXT_TOKEN)) { 4142290001Sglebius struct hosts_entry *he; 4143290001Sglebius size_t namelen; 4144290001Sglebius if ((hash = strchr(hostname, '#'))) { 4145290001Sglebius if (hash == hostname) 4146290001Sglebius return 0; 4147290001Sglebius *hash = '\0'; 4148290001Sglebius } 4149290001Sglebius 4150290001Sglebius namelen = strlen(hostname); 4151290001Sglebius 4152290001Sglebius he = mm_calloc(1, sizeof(struct hosts_entry)+namelen); 4153290001Sglebius if (!he) 4154290001Sglebius return -1; 4155290001Sglebius EVUTIL_ASSERT(socklen <= (int)sizeof(he->addr)); 4156290001Sglebius memcpy(&he->addr, &ss, socklen); 4157290001Sglebius memcpy(he->hostname, hostname, namelen+1); 4158290001Sglebius he->addrlen = socklen; 4159290001Sglebius 4160290001Sglebius TAILQ_INSERT_TAIL(&base->hostsdb, he, next); 4161290001Sglebius 4162290001Sglebius if (hash) 4163290001Sglebius return 0; 4164290001Sglebius } 4165290001Sglebius 4166290001Sglebius return 0; 4167290001Sglebius#undef NEXT_TOKEN 4168290001Sglebius} 4169290001Sglebius 4170290001Sglebiusstatic int 4171290001Sglebiusevdns_base_load_hosts_impl(struct evdns_base *base, const char *hosts_fname) 4172290001Sglebius{ 4173290001Sglebius char *str=NULL, *cp, *eol; 4174290001Sglebius size_t len; 4175290001Sglebius int err=0; 4176290001Sglebius 4177290001Sglebius ASSERT_LOCKED(base); 4178290001Sglebius 4179290001Sglebius if (hosts_fname == NULL || 4180290001Sglebius (err = evutil_read_file_(hosts_fname, &str, &len, 0)) < 0) { 4181290001Sglebius char tmp[64]; 4182290001Sglebius strlcpy(tmp, "127.0.0.1 localhost", sizeof(tmp)); 4183290001Sglebius evdns_base_parse_hosts_line(base, tmp); 4184290001Sglebius strlcpy(tmp, "::1 localhost", sizeof(tmp)); 4185290001Sglebius evdns_base_parse_hosts_line(base, tmp); 4186290001Sglebius return err ? -1 : 0; 4187290001Sglebius } 4188290001Sglebius 4189290001Sglebius /* This will break early if there is a NUL in the hosts file. 4190290001Sglebius * Probably not a problem.*/ 4191290001Sglebius cp = str; 4192290001Sglebius for (;;) { 4193290001Sglebius eol = strchr(cp, '\n'); 4194290001Sglebius 4195290001Sglebius if (eol) { 4196290001Sglebius *eol = '\0'; 4197290001Sglebius evdns_base_parse_hosts_line(base, cp); 4198290001Sglebius cp = eol+1; 4199290001Sglebius } else { 4200290001Sglebius evdns_base_parse_hosts_line(base, cp); 4201290001Sglebius break; 4202290001Sglebius } 4203290001Sglebius } 4204290001Sglebius 4205290001Sglebius mm_free(str); 4206290001Sglebius return 0; 4207290001Sglebius} 4208290001Sglebius 4209290001Sglebiusint 4210290001Sglebiusevdns_base_load_hosts(struct evdns_base *base, const char *hosts_fname) 4211290001Sglebius{ 4212290001Sglebius int res; 4213290001Sglebius if (!base) 4214290001Sglebius base = current_base; 4215290001Sglebius EVDNS_LOCK(base); 4216290001Sglebius res = evdns_base_load_hosts_impl(base, hosts_fname); 4217290001Sglebius EVDNS_UNLOCK(base); 4218290001Sglebius return res; 4219290001Sglebius} 4220290001Sglebius 4221290001Sglebius/* A single request for a getaddrinfo, either v4 or v6. */ 4222290001Sglebiusstruct getaddrinfo_subrequest { 4223290001Sglebius struct evdns_request *r; 4224290001Sglebius ev_uint32_t type; 4225290001Sglebius}; 4226290001Sglebius 4227290001Sglebius/* State data used to implement an in-progress getaddrinfo. */ 4228290001Sglebiusstruct evdns_getaddrinfo_request { 4229290001Sglebius struct evdns_base *evdns_base; 4230290001Sglebius /* Copy of the modified 'hints' data that we'll use to build 4231290001Sglebius * answers. */ 4232290001Sglebius struct evutil_addrinfo hints; 4233290001Sglebius /* The callback to invoke when we're done */ 4234290001Sglebius evdns_getaddrinfo_cb user_cb; 4235290001Sglebius /* User-supplied data to give to the callback. */ 4236290001Sglebius void *user_data; 4237290001Sglebius /* The port to use when building sockaddrs. */ 4238290001Sglebius ev_uint16_t port; 4239290001Sglebius /* The sub_request for an A record (if any) */ 4240290001Sglebius struct getaddrinfo_subrequest ipv4_request; 4241290001Sglebius /* The sub_request for an AAAA record (if any) */ 4242290001Sglebius struct getaddrinfo_subrequest ipv6_request; 4243290001Sglebius 4244290001Sglebius /* The cname result that we were told (if any) */ 4245290001Sglebius char *cname_result; 4246290001Sglebius 4247290001Sglebius /* If we have one request answered and one request still inflight, 4248290001Sglebius * then this field holds the answer from the first request... */ 4249290001Sglebius struct evutil_addrinfo *pending_result; 4250290001Sglebius /* And this event is a timeout that will tell us to cancel the second 4251290001Sglebius * request if it's taking a long time. */ 4252290001Sglebius struct event timeout; 4253290001Sglebius 4254290001Sglebius /* And this field holds the error code from the first request... */ 4255290001Sglebius int pending_error; 4256290001Sglebius /* If this is set, the user canceled this request. */ 4257290001Sglebius unsigned user_canceled : 1; 4258290001Sglebius /* If this is set, the user can no longer cancel this request; we're 4259290001Sglebius * just waiting for the free. */ 4260290001Sglebius unsigned request_done : 1; 4261290001Sglebius}; 4262290001Sglebius 4263290001Sglebius/* Convert an evdns errors to the equivalent getaddrinfo error. */ 4264290001Sglebiusstatic int 4265290001Sglebiusevdns_err_to_getaddrinfo_err(int e1) 4266290001Sglebius{ 4267290001Sglebius /* XXX Do this better! */ 4268290001Sglebius if (e1 == DNS_ERR_NONE) 4269290001Sglebius return 0; 4270290001Sglebius else if (e1 == DNS_ERR_NOTEXIST) 4271290001Sglebius return EVUTIL_EAI_NONAME; 4272290001Sglebius else 4273290001Sglebius return EVUTIL_EAI_FAIL; 4274290001Sglebius} 4275290001Sglebius 4276290001Sglebius/* Return the more informative of two getaddrinfo errors. */ 4277290001Sglebiusstatic int 4278290001Sglebiusgetaddrinfo_merge_err(int e1, int e2) 4279290001Sglebius{ 4280290001Sglebius /* XXXX be cleverer here. */ 4281290001Sglebius if (e1 == 0) 4282290001Sglebius return e2; 4283290001Sglebius else 4284290001Sglebius return e1; 4285290001Sglebius} 4286290001Sglebius 4287290001Sglebiusstatic void 4288290001Sglebiusfree_getaddrinfo_request(struct evdns_getaddrinfo_request *data) 4289290001Sglebius{ 4290290001Sglebius /* DO NOT CALL this if either of the requests is pending. Only once 4291290001Sglebius * both callbacks have been invoked is it safe to free the request */ 4292290001Sglebius if (data->pending_result) 4293290001Sglebius evutil_freeaddrinfo(data->pending_result); 4294290001Sglebius if (data->cname_result) 4295290001Sglebius mm_free(data->cname_result); 4296290001Sglebius event_del(&data->timeout); 4297290001Sglebius mm_free(data); 4298290001Sglebius return; 4299290001Sglebius} 4300290001Sglebius 4301290001Sglebiusstatic void 4302290001Sglebiusadd_cname_to_reply(struct evdns_getaddrinfo_request *data, 4303290001Sglebius struct evutil_addrinfo *ai) 4304290001Sglebius{ 4305290001Sglebius if (data->cname_result && ai) { 4306290001Sglebius ai->ai_canonname = data->cname_result; 4307290001Sglebius data->cname_result = NULL; 4308290001Sglebius } 4309290001Sglebius} 4310290001Sglebius 4311290001Sglebius/* Callback: invoked when one request in a mixed-format A/AAAA getaddrinfo 4312290001Sglebius * request has finished, but the other one took too long to answer. Pass 4313290001Sglebius * along the answer we got, and cancel the other request. 4314290001Sglebius */ 4315290001Sglebiusstatic void 4316290001Sglebiusevdns_getaddrinfo_timeout_cb(evutil_socket_t fd, short what, void *ptr) 4317290001Sglebius{ 4318290001Sglebius int v4_timedout = 0, v6_timedout = 0; 4319290001Sglebius struct evdns_getaddrinfo_request *data = ptr; 4320290001Sglebius 4321290001Sglebius /* Cancel any pending requests, and note which one */ 4322290001Sglebius if (data->ipv4_request.r) { 4323290001Sglebius /* XXXX This does nothing if the request's callback is already 4324290001Sglebius * running (pending_cb is set). */ 4325290001Sglebius evdns_cancel_request(NULL, data->ipv4_request.r); 4326290001Sglebius v4_timedout = 1; 4327290001Sglebius EVDNS_LOCK(data->evdns_base); 4328290001Sglebius ++data->evdns_base->getaddrinfo_ipv4_timeouts; 4329290001Sglebius EVDNS_UNLOCK(data->evdns_base); 4330290001Sglebius } 4331290001Sglebius if (data->ipv6_request.r) { 4332290001Sglebius /* XXXX This does nothing if the request's callback is already 4333290001Sglebius * running (pending_cb is set). */ 4334290001Sglebius evdns_cancel_request(NULL, data->ipv6_request.r); 4335290001Sglebius v6_timedout = 1; 4336290001Sglebius EVDNS_LOCK(data->evdns_base); 4337290001Sglebius ++data->evdns_base->getaddrinfo_ipv6_timeouts; 4338290001Sglebius EVDNS_UNLOCK(data->evdns_base); 4339290001Sglebius } 4340290001Sglebius 4341290001Sglebius /* We only use this timeout callback when we have an answer for 4342290001Sglebius * one address. */ 4343290001Sglebius EVUTIL_ASSERT(!v4_timedout || !v6_timedout); 4344290001Sglebius 4345290001Sglebius /* Report the outcome of the other request that didn't time out. */ 4346290001Sglebius if (data->pending_result) { 4347290001Sglebius add_cname_to_reply(data, data->pending_result); 4348290001Sglebius data->user_cb(0, data->pending_result, data->user_data); 4349290001Sglebius data->pending_result = NULL; 4350290001Sglebius } else { 4351290001Sglebius int e = data->pending_error; 4352290001Sglebius if (!e) 4353290001Sglebius e = EVUTIL_EAI_AGAIN; 4354290001Sglebius data->user_cb(e, NULL, data->user_data); 4355290001Sglebius } 4356290001Sglebius 4357290001Sglebius data->user_cb = NULL; /* prevent double-call if evdns callbacks are 4358290001Sglebius * in-progress. XXXX It would be better if this 4359290001Sglebius * weren't necessary. */ 4360290001Sglebius 4361290001Sglebius if (!v4_timedout && !v6_timedout) { 4362290001Sglebius /* should be impossible? XXXX */ 4363290001Sglebius free_getaddrinfo_request(data); 4364290001Sglebius } 4365290001Sglebius} 4366290001Sglebius 4367290001Sglebiusstatic int 4368290001Sglebiusevdns_getaddrinfo_set_timeout(struct evdns_base *evdns_base, 4369290001Sglebius struct evdns_getaddrinfo_request *data) 4370290001Sglebius{ 4371290001Sglebius return event_add(&data->timeout, &evdns_base->global_getaddrinfo_allow_skew); 4372290001Sglebius} 4373290001Sglebius 4374290001Sglebiusstatic inline int 4375290001Sglebiusevdns_result_is_answer(int result) 4376290001Sglebius{ 4377290001Sglebius return (result != DNS_ERR_NOTIMPL && result != DNS_ERR_REFUSED && 4378290001Sglebius result != DNS_ERR_SERVERFAILED && result != DNS_ERR_CANCEL); 4379290001Sglebius} 4380290001Sglebius 4381290001Sglebiusstatic void 4382290001Sglebiusevdns_getaddrinfo_gotresolve(int result, char type, int count, 4383290001Sglebius int ttl, void *addresses, void *arg) 4384290001Sglebius{ 4385290001Sglebius int i; 4386290001Sglebius struct getaddrinfo_subrequest *req = arg; 4387290001Sglebius struct getaddrinfo_subrequest *other_req; 4388290001Sglebius struct evdns_getaddrinfo_request *data; 4389290001Sglebius 4390290001Sglebius struct evutil_addrinfo *res; 4391290001Sglebius 4392290001Sglebius struct sockaddr_in sin; 4393290001Sglebius struct sockaddr_in6 sin6; 4394290001Sglebius struct sockaddr *sa; 4395290001Sglebius int socklen, addrlen; 4396290001Sglebius void *addrp; 4397290001Sglebius int err; 4398290001Sglebius int user_canceled; 4399290001Sglebius 4400290001Sglebius EVUTIL_ASSERT(req->type == DNS_IPv4_A || req->type == DNS_IPv6_AAAA); 4401290001Sglebius if (req->type == DNS_IPv4_A) { 4402290001Sglebius data = EVUTIL_UPCAST(req, struct evdns_getaddrinfo_request, ipv4_request); 4403290001Sglebius other_req = &data->ipv6_request; 4404290001Sglebius } else { 4405290001Sglebius data = EVUTIL_UPCAST(req, struct evdns_getaddrinfo_request, ipv6_request); 4406290001Sglebius other_req = &data->ipv4_request; 4407290001Sglebius } 4408290001Sglebius 4409290001Sglebius EVDNS_LOCK(data->evdns_base); 4410290001Sglebius if (evdns_result_is_answer(result)) { 4411290001Sglebius if (req->type == DNS_IPv4_A) 4412290001Sglebius ++data->evdns_base->getaddrinfo_ipv4_answered; 4413290001Sglebius else 4414290001Sglebius ++data->evdns_base->getaddrinfo_ipv6_answered; 4415290001Sglebius } 4416290001Sglebius user_canceled = data->user_canceled; 4417290001Sglebius if (other_req->r == NULL) 4418290001Sglebius data->request_done = 1; 4419290001Sglebius EVDNS_UNLOCK(data->evdns_base); 4420290001Sglebius 4421290001Sglebius req->r = NULL; 4422290001Sglebius 4423290001Sglebius if (result == DNS_ERR_CANCEL && ! user_canceled) { 4424290001Sglebius /* Internal cancel request from timeout or internal error. 4425290001Sglebius * we already answered the user. */ 4426290001Sglebius if (other_req->r == NULL) 4427290001Sglebius free_getaddrinfo_request(data); 4428290001Sglebius return; 4429290001Sglebius } 4430290001Sglebius 4431290001Sglebius if (data->user_cb == NULL) { 4432290001Sglebius /* We already answered. XXXX This shouldn't be needed; see 4433290001Sglebius * comments in evdns_getaddrinfo_timeout_cb */ 4434290001Sglebius free_getaddrinfo_request(data); 4435290001Sglebius return; 4436290001Sglebius } 4437290001Sglebius 4438290001Sglebius if (result == DNS_ERR_NONE) { 4439290001Sglebius if (count == 0) 4440290001Sglebius err = EVUTIL_EAI_NODATA; 4441290001Sglebius else 4442290001Sglebius err = 0; 4443290001Sglebius } else { 4444290001Sglebius err = evdns_err_to_getaddrinfo_err(result); 4445290001Sglebius } 4446290001Sglebius 4447290001Sglebius if (err) { 4448290001Sglebius /* Looks like we got an error. */ 4449290001Sglebius if (other_req->r) { 4450290001Sglebius /* The other request is still working; maybe it will 4451290001Sglebius * succeed. */ 4452290001Sglebius /* XXXX handle failure from set_timeout */ 4453290001Sglebius evdns_getaddrinfo_set_timeout(data->evdns_base, data); 4454290001Sglebius data->pending_error = err; 4455290001Sglebius return; 4456290001Sglebius } 4457290001Sglebius 4458290001Sglebius if (user_canceled) { 4459290001Sglebius data->user_cb(EVUTIL_EAI_CANCEL, NULL, data->user_data); 4460290001Sglebius } else if (data->pending_result) { 4461290001Sglebius /* If we have an answer waiting, and we weren't 4462290001Sglebius * canceled, ignore this error. */ 4463290001Sglebius add_cname_to_reply(data, data->pending_result); 4464290001Sglebius data->user_cb(0, data->pending_result, data->user_data); 4465290001Sglebius data->pending_result = NULL; 4466290001Sglebius } else { 4467290001Sglebius if (data->pending_error) 4468290001Sglebius err = getaddrinfo_merge_err(err, 4469290001Sglebius data->pending_error); 4470290001Sglebius data->user_cb(err, NULL, data->user_data); 4471290001Sglebius } 4472290001Sglebius free_getaddrinfo_request(data); 4473290001Sglebius return; 4474290001Sglebius } else if (user_canceled) { 4475290001Sglebius if (other_req->r) { 4476290001Sglebius /* The other request is still working; let it hit this 4477290001Sglebius * callback with EVUTIL_EAI_CANCEL callback and report 4478290001Sglebius * the failure. */ 4479290001Sglebius return; 4480290001Sglebius } 4481290001Sglebius data->user_cb(EVUTIL_EAI_CANCEL, NULL, data->user_data); 4482290001Sglebius free_getaddrinfo_request(data); 4483290001Sglebius return; 4484290001Sglebius } 4485290001Sglebius 4486290001Sglebius /* Looks like we got some answers. We should turn them into addrinfos 4487290001Sglebius * and then either queue those or return them all. */ 4488290001Sglebius EVUTIL_ASSERT(type == DNS_IPv4_A || type == DNS_IPv6_AAAA); 4489290001Sglebius 4490290001Sglebius if (type == DNS_IPv4_A) { 4491290001Sglebius memset(&sin, 0, sizeof(sin)); 4492290001Sglebius sin.sin_family = AF_INET; 4493290001Sglebius sin.sin_port = htons(data->port); 4494290001Sglebius 4495290001Sglebius sa = (struct sockaddr *)&sin; 4496290001Sglebius socklen = sizeof(sin); 4497290001Sglebius addrlen = 4; 4498290001Sglebius addrp = &sin.sin_addr.s_addr; 4499290001Sglebius } else { 4500290001Sglebius memset(&sin6, 0, sizeof(sin6)); 4501290001Sglebius sin6.sin6_family = AF_INET6; 4502290001Sglebius sin6.sin6_port = htons(data->port); 4503290001Sglebius 4504290001Sglebius sa = (struct sockaddr *)&sin6; 4505290001Sglebius socklen = sizeof(sin6); 4506290001Sglebius addrlen = 16; 4507290001Sglebius addrp = &sin6.sin6_addr.s6_addr; 4508290001Sglebius } 4509290001Sglebius 4510290001Sglebius res = NULL; 4511290001Sglebius for (i=0; i < count; ++i) { 4512290001Sglebius struct evutil_addrinfo *ai; 4513290001Sglebius memcpy(addrp, ((char*)addresses)+i*addrlen, addrlen); 4514290001Sglebius ai = evutil_new_addrinfo_(sa, socklen, &data->hints); 4515290001Sglebius if (!ai) { 4516290001Sglebius if (other_req->r) { 4517290001Sglebius evdns_cancel_request(NULL, other_req->r); 4518290001Sglebius } 4519290001Sglebius data->user_cb(EVUTIL_EAI_MEMORY, NULL, data->user_data); 4520290001Sglebius if (res) 4521290001Sglebius evutil_freeaddrinfo(res); 4522290001Sglebius 4523290001Sglebius if (other_req->r == NULL) 4524290001Sglebius free_getaddrinfo_request(data); 4525290001Sglebius return; 4526290001Sglebius } 4527290001Sglebius res = evutil_addrinfo_append_(res, ai); 4528290001Sglebius } 4529290001Sglebius 4530290001Sglebius if (other_req->r) { 4531290001Sglebius /* The other request is still in progress; wait for it */ 4532290001Sglebius /* XXXX handle failure from set_timeout */ 4533290001Sglebius evdns_getaddrinfo_set_timeout(data->evdns_base, data); 4534290001Sglebius data->pending_result = res; 4535290001Sglebius return; 4536290001Sglebius } else { 4537290001Sglebius /* The other request is done or never started; append its 4538290001Sglebius * results (if any) and return them. */ 4539290001Sglebius if (data->pending_result) { 4540290001Sglebius if (req->type == DNS_IPv4_A) 4541290001Sglebius res = evutil_addrinfo_append_(res, 4542290001Sglebius data->pending_result); 4543290001Sglebius else 4544290001Sglebius res = evutil_addrinfo_append_( 4545290001Sglebius data->pending_result, res); 4546290001Sglebius data->pending_result = NULL; 4547290001Sglebius } 4548290001Sglebius 4549290001Sglebius /* Call the user callback. */ 4550290001Sglebius add_cname_to_reply(data, res); 4551290001Sglebius data->user_cb(0, res, data->user_data); 4552290001Sglebius 4553290001Sglebius /* Free data. */ 4554290001Sglebius free_getaddrinfo_request(data); 4555290001Sglebius } 4556290001Sglebius} 4557290001Sglebius 4558290001Sglebiusstatic struct hosts_entry * 4559290001Sglebiusfind_hosts_entry(struct evdns_base *base, const char *hostname, 4560290001Sglebius struct hosts_entry *find_after) 4561290001Sglebius{ 4562290001Sglebius struct hosts_entry *e; 4563290001Sglebius 4564290001Sglebius if (find_after) 4565290001Sglebius e = TAILQ_NEXT(find_after, next); 4566290001Sglebius else 4567290001Sglebius e = TAILQ_FIRST(&base->hostsdb); 4568290001Sglebius 4569290001Sglebius for (; e; e = TAILQ_NEXT(e, next)) { 4570290001Sglebius if (!evutil_ascii_strcasecmp(e->hostname, hostname)) 4571290001Sglebius return e; 4572290001Sglebius } 4573290001Sglebius return NULL; 4574290001Sglebius} 4575290001Sglebius 4576290001Sglebiusstatic int 4577290001Sglebiusevdns_getaddrinfo_fromhosts(struct evdns_base *base, 4578290001Sglebius const char *nodename, struct evutil_addrinfo *hints, ev_uint16_t port, 4579290001Sglebius struct evutil_addrinfo **res) 4580290001Sglebius{ 4581290001Sglebius int n_found = 0; 4582290001Sglebius struct hosts_entry *e; 4583290001Sglebius struct evutil_addrinfo *ai=NULL; 4584290001Sglebius int f = hints->ai_family; 4585290001Sglebius 4586290001Sglebius EVDNS_LOCK(base); 4587290001Sglebius for (e = find_hosts_entry(base, nodename, NULL); e; 4588290001Sglebius e = find_hosts_entry(base, nodename, e)) { 4589290001Sglebius struct evutil_addrinfo *ai_new; 4590290001Sglebius ++n_found; 4591290001Sglebius if ((e->addr.sa.sa_family == AF_INET && f == PF_INET6) || 4592290001Sglebius (e->addr.sa.sa_family == AF_INET6 && f == PF_INET)) 4593290001Sglebius continue; 4594290001Sglebius ai_new = evutil_new_addrinfo_(&e->addr.sa, e->addrlen, hints); 4595290001Sglebius if (!ai_new) { 4596290001Sglebius n_found = 0; 4597290001Sglebius goto out; 4598290001Sglebius } 4599290001Sglebius sockaddr_setport(ai_new->ai_addr, port); 4600290001Sglebius ai = evutil_addrinfo_append_(ai, ai_new); 4601290001Sglebius } 4602290001Sglebius EVDNS_UNLOCK(base); 4603290001Sglebiusout: 4604290001Sglebius if (n_found) { 4605290001Sglebius /* Note that we return an empty answer if we found entries for 4606290001Sglebius * this hostname but none were of the right address type. */ 4607290001Sglebius *res = ai; 4608290001Sglebius return 0; 4609290001Sglebius } else { 4610290001Sglebius if (ai) 4611290001Sglebius evutil_freeaddrinfo(ai); 4612290001Sglebius return -1; 4613290001Sglebius } 4614290001Sglebius} 4615290001Sglebius 4616290001Sglebiusstruct evdns_getaddrinfo_request * 4617290001Sglebiusevdns_getaddrinfo(struct evdns_base *dns_base, 4618290001Sglebius const char *nodename, const char *servname, 4619290001Sglebius const struct evutil_addrinfo *hints_in, 4620290001Sglebius evdns_getaddrinfo_cb cb, void *arg) 4621290001Sglebius{ 4622290001Sglebius struct evdns_getaddrinfo_request *data; 4623290001Sglebius struct evutil_addrinfo hints; 4624290001Sglebius struct evutil_addrinfo *res = NULL; 4625290001Sglebius int err; 4626290001Sglebius int port = 0; 4627290001Sglebius int want_cname = 0; 4628290001Sglebius 4629290001Sglebius if (!dns_base) { 4630290001Sglebius dns_base = current_base; 4631290001Sglebius if (!dns_base) { 4632290001Sglebius log(EVDNS_LOG_WARN, 4633290001Sglebius "Call to getaddrinfo_async with no " 4634290001Sglebius "evdns_base configured."); 4635290001Sglebius cb(EVUTIL_EAI_FAIL, NULL, arg); /* ??? better error? */ 4636290001Sglebius return NULL; 4637290001Sglebius } 4638290001Sglebius } 4639290001Sglebius 4640290001Sglebius /* If we _must_ answer this immediately, do so. */ 4641290001Sglebius if ((hints_in && (hints_in->ai_flags & EVUTIL_AI_NUMERICHOST))) { 4642290001Sglebius res = NULL; 4643290001Sglebius err = evutil_getaddrinfo(nodename, servname, hints_in, &res); 4644290001Sglebius cb(err, res, arg); 4645290001Sglebius return NULL; 4646290001Sglebius } 4647290001Sglebius 4648290001Sglebius if (hints_in) { 4649290001Sglebius memcpy(&hints, hints_in, sizeof(hints)); 4650290001Sglebius } else { 4651290001Sglebius memset(&hints, 0, sizeof(hints)); 4652290001Sglebius hints.ai_family = PF_UNSPEC; 4653290001Sglebius } 4654290001Sglebius 4655290001Sglebius evutil_adjust_hints_for_addrconfig_(&hints); 4656290001Sglebius 4657290001Sglebius /* Now try to see if we _can_ answer immediately. */ 4658290001Sglebius /* (It would be nice to do this by calling getaddrinfo directly, with 4659290001Sglebius * AI_NUMERICHOST, on plaforms that have it, but we can't: there isn't 4660290001Sglebius * a reliable way to distinguish the "that wasn't a numeric host!" case 4661290001Sglebius * from any other EAI_NONAME cases.) */ 4662290001Sglebius err = evutil_getaddrinfo_common_(nodename, servname, &hints, &res, &port); 4663290001Sglebius if (err != EVUTIL_EAI_NEED_RESOLVE) { 4664290001Sglebius cb(err, res, arg); 4665290001Sglebius return NULL; 4666290001Sglebius } 4667290001Sglebius 4668290001Sglebius /* If there is an entry in the hosts file, we should give it now. */ 4669290001Sglebius if (!evdns_getaddrinfo_fromhosts(dns_base, nodename, &hints, port, &res)) { 4670290001Sglebius cb(0, res, arg); 4671290001Sglebius return NULL; 4672290001Sglebius } 4673290001Sglebius 4674290001Sglebius /* Okay, things are serious now. We're going to need to actually 4675290001Sglebius * launch a request. 4676290001Sglebius */ 4677290001Sglebius data = mm_calloc(1,sizeof(struct evdns_getaddrinfo_request)); 4678290001Sglebius if (!data) { 4679290001Sglebius cb(EVUTIL_EAI_MEMORY, NULL, arg); 4680290001Sglebius return NULL; 4681290001Sglebius } 4682290001Sglebius 4683290001Sglebius memcpy(&data->hints, &hints, sizeof(data->hints)); 4684290001Sglebius data->port = (ev_uint16_t)port; 4685290001Sglebius data->ipv4_request.type = DNS_IPv4_A; 4686290001Sglebius data->ipv6_request.type = DNS_IPv6_AAAA; 4687290001Sglebius data->user_cb = cb; 4688290001Sglebius data->user_data = arg; 4689290001Sglebius data->evdns_base = dns_base; 4690290001Sglebius 4691290001Sglebius want_cname = (hints.ai_flags & EVUTIL_AI_CANONNAME); 4692290001Sglebius 4693290001Sglebius /* If we are asked for a PF_UNSPEC address, we launch two requests in 4694290001Sglebius * parallel: one for an A address and one for an AAAA address. We 4695290001Sglebius * can't send just one request, since many servers only answer one 4696290001Sglebius * question per DNS request. 4697290001Sglebius * 4698290001Sglebius * Once we have the answer to one request, we allow for a short 4699290001Sglebius * timeout before we report it, to see if the other one arrives. If 4700290001Sglebius * they both show up in time, then we report both the answers. 4701290001Sglebius * 4702290001Sglebius * If too many addresses of one type time out or fail, we should stop 4703290001Sglebius * launching those requests. (XXX we don't do that yet.) 4704290001Sglebius */ 4705290001Sglebius 4706290001Sglebius if (hints.ai_family != PF_INET6) { 4707290001Sglebius log(EVDNS_LOG_DEBUG, "Sending request for %s on ipv4 as %p", 4708290001Sglebius nodename, &data->ipv4_request); 4709290001Sglebius 4710290001Sglebius data->ipv4_request.r = evdns_base_resolve_ipv4(dns_base, 4711290001Sglebius nodename, 0, evdns_getaddrinfo_gotresolve, 4712290001Sglebius &data->ipv4_request); 4713290001Sglebius if (want_cname && data->ipv4_request.r) 4714290001Sglebius data->ipv4_request.r->current_req->put_cname_in_ptr = 4715290001Sglebius &data->cname_result; 4716290001Sglebius } 4717290001Sglebius if (hints.ai_family != PF_INET) { 4718290001Sglebius log(EVDNS_LOG_DEBUG, "Sending request for %s on ipv6 as %p", 4719290001Sglebius nodename, &data->ipv6_request); 4720290001Sglebius 4721290001Sglebius data->ipv6_request.r = evdns_base_resolve_ipv6(dns_base, 4722290001Sglebius nodename, 0, evdns_getaddrinfo_gotresolve, 4723290001Sglebius &data->ipv6_request); 4724290001Sglebius if (want_cname && data->ipv6_request.r) 4725290001Sglebius data->ipv6_request.r->current_req->put_cname_in_ptr = 4726290001Sglebius &data->cname_result; 4727290001Sglebius } 4728290001Sglebius 4729290001Sglebius evtimer_assign(&data->timeout, dns_base->event_base, 4730290001Sglebius evdns_getaddrinfo_timeout_cb, data); 4731290001Sglebius 4732290001Sglebius if (data->ipv4_request.r || data->ipv6_request.r) { 4733290001Sglebius return data; 4734290001Sglebius } else { 4735290001Sglebius mm_free(data); 4736290001Sglebius cb(EVUTIL_EAI_FAIL, NULL, arg); 4737290001Sglebius return NULL; 4738290001Sglebius } 4739290001Sglebius} 4740290001Sglebius 4741290001Sglebiusvoid 4742290001Sglebiusevdns_getaddrinfo_cancel(struct evdns_getaddrinfo_request *data) 4743290001Sglebius{ 4744290001Sglebius EVDNS_LOCK(data->evdns_base); 4745290001Sglebius if (data->request_done) { 4746290001Sglebius EVDNS_UNLOCK(data->evdns_base); 4747290001Sglebius return; 4748290001Sglebius } 4749290001Sglebius event_del(&data->timeout); 4750290001Sglebius data->user_canceled = 1; 4751290001Sglebius if (data->ipv4_request.r) 4752290001Sglebius evdns_cancel_request(data->evdns_base, data->ipv4_request.r); 4753290001Sglebius if (data->ipv6_request.r) 4754290001Sglebius evdns_cancel_request(data->evdns_base, data->ipv6_request.r); 4755290001Sglebius EVDNS_UNLOCK(data->evdns_base); 4756290001Sglebius} 4757