1/* dnsmasq is Copyright (c) 2000-2005 Simon Kelley 2 3 This program is free software; you can redistribute it and/or modify 4 it under the terms of the GNU General Public License as published by 5 the Free Software Foundation; version 2 dated June, 1991. 6 7 This program is distributed in the hope that it will be useful, 8 but WITHOUT ANY WARRANTY; without even the implied warranty of 9 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 10 GNU General Public License for more details. 11*/ 12 13#define COPYRIGHT "Copyright (C) 2000-2006 Simon Kelley" 14 15/* get these before config.h for IPv6 stuff... */ 16#include <sys/types.h> 17#include <netinet/in.h> 18 19#ifdef __APPLE__ 20/* need this before arpa/nameser.h */ 21# define BIND_8_COMPAT 22#endif 23#include <arpa/nameser.h> 24 25/* and this. */ 26#include <getopt.h> 27 28#include "config.h" 29 30#define gettext_noop(S) (S) 31#ifdef NO_GETTEXT 32# define _(S) (S) 33#else 34# include <libintl.h> 35# include <locale.h> 36# define _(S) gettext(S) 37#endif 38 39#include <arpa/inet.h> 40#include <sys/stat.h> 41#include <sys/socket.h> 42#include <sys/ioctl.h> 43#include <sys/select.h> 44#include <sys/wait.h> 45#include <sys/time.h> 46#include <limits.h> 47#include <net/if.h> 48#include <unistd.h> 49#include <stdio.h> 50#include <string.h> 51#include <stdlib.h> 52#include <fcntl.h> 53#include <ctype.h> 54#include <signal.h> 55#include <time.h> 56#include <errno.h> 57#include <pwd.h> 58#include <grp.h> 59#include <stdarg.h> 60#if defined(__OpenBSD__) || defined(__NetBSD__) 61# include <netinet/if_ether.h> 62#else 63# include <net/ethernet.h> 64#endif 65#include <net/if_arp.h> 66#include <netinet/in_systm.h> 67#include <netinet/ip.h> 68#include <netinet/ip_icmp.h> 69#include <sys/uio.h> 70#include <syslog.h> 71#include <dirent.h> 72#ifndef HAVE_LINUX_NETWORK 73# include <net/if_dl.h> 74#endif 75 76#ifdef HAVE_LINUX_NETWORK 77#include <linux/capability.h> 78/* There doesn't seem to be a universally-available 79 userpace header for this. */ 80extern int capset(cap_user_header_t header, cap_user_data_t data); 81#include <sys/prctl.h> 82#endif 83 84/* Min buffer size: we check after adding each record, so there must be 85 memory for the largest packet, and the largest record so the 86 min for DNS is PACKETSZ+MAXDNAME+RRFIXEDSZ which is < 1000. 87 This might be increased is EDNS packet size if greater than the minimum. 88*/ 89#define DNSMASQ_PACKETSZ PACKETSZ+MAXDNAME+RRFIXEDSZ 90 91#define OPT_BOGUSPRIV 1 92#define OPT_FILTER 2 93#define OPT_LOG 4 94#define OPT_SELFMX 8 95#define OPT_NO_HOSTS 16 96#define OPT_NO_POLL 32 97#define OPT_DEBUG 64 98#define OPT_ORDER 128 99#define OPT_NO_RESOLV 256 100#define OPT_EXPAND 512 101#define OPT_LOCALMX 1024 102#define OPT_NO_NEG 2048 103#define OPT_NODOTS_LOCAL 4096 104#define OPT_NOWILD 8192 105#define OPT_ETHERS 16384 106#define OPT_RESOLV_DOMAIN 32768 107#define OPT_NO_FORK 65536 108#define OPT_AUTHORITATIVE 131072 109#define OPT_LOCALISE 262144 110#define OPT_DBUS 524288 111#define OPT_BOOTP_DYNAMIC 1048576 112#define OPT_NO_PING 2097152 113#define OPT_LEASE_RO 4194304 114 115struct all_addr { 116 union { 117 struct in_addr addr4; 118#ifdef HAVE_IPV6 119 struct in6_addr addr6; 120#endif 121 } addr; 122}; 123 124struct bogus_addr { 125 struct in_addr addr; 126 struct bogus_addr *next; 127}; 128 129/* dns doctor param */ 130struct doctor { 131 struct in_addr in, out, mask; 132 struct doctor *next; 133}; 134 135struct mx_srv_record { 136 char *name, *target; 137 int issrv, srvport, priority, weight; 138 unsigned int offset; 139 struct mx_srv_record *next; 140}; 141 142struct txt_record { 143 char *name, *txt; 144 unsigned short class, len; 145 struct txt_record *next; 146}; 147 148union bigname { 149 char name[MAXDNAME]; 150 union bigname *next; /* freelist */ 151}; 152 153struct crec { 154 struct crec *next, *prev, *hash_next; 155 time_t ttd; /* time to die */ 156 int uid; 157 union { 158 struct all_addr addr; 159 struct { 160 struct crec *cache; 161 int uid; 162 } cname; 163 } addr; 164 unsigned short flags; 165 union { 166 char sname[SMALLDNAME]; 167 union bigname *bname; 168 char *namep; 169 } name; 170}; 171 172#define F_IMMORTAL 1 173#define F_CONFIG 2 174#define F_REVERSE 4 175#define F_FORWARD 8 176#define F_DHCP 16 177#define F_NEG 32 178#define F_HOSTS 64 179#define F_IPV4 128 180#define F_IPV6 256 181#define F_BIGNAME 512 182#define F_UPSTREAM 1024 183#define F_SERVER 2048 184#define F_NXDOMAIN 4096 185#define F_QUERY 8192 186#define F_CNAME 16384 187#define F_NOERR 32768 188 189/* struct sockaddr is not large enough to hold any address, 190 and specifically not big enough to hold an IPv6 address. 191 Blech. Roll our own. */ 192union mysockaddr { 193 struct sockaddr sa; 194 struct sockaddr_in in; 195#ifdef HAVE_BROKEN_SOCKADDR_IN6 196 /* early versions of glibc don't include sin6_scope_id in sockaddr_in6 197 but latest kernels _require_ it to be set. The choice is to have 198 dnsmasq fail to compile on back-level libc or fail to run 199 on latest kernels with IPv6. Or to do this: sorry that it's so gross. */ 200 struct my_sockaddr_in6 { 201 sa_family_t sin6_family; /* AF_INET6 */ 202 uint16_t sin6_port; /* transport layer port # */ 203 uint32_t sin6_flowinfo; /* IPv6 traffic class & flow info */ 204 struct in6_addr sin6_addr; /* IPv6 address */ 205 uint32_t sin6_scope_id; /* set of interfaces for a scope */ 206 } in6; 207#elif defined(HAVE_IPV6) 208 struct sockaddr_in6 in6; 209#endif 210}; 211 212#define SERV_FROM_RESOLV 1 /* 1 for servers from resolv, 0 for command line. */ 213#define SERV_NO_ADDR 2 /* no server, this domain is local only */ 214#define SERV_LITERAL_ADDRESS 4 /* addr is the answer, not the server */ 215#define SERV_HAS_SOURCE 8 /* source address specified */ 216#define SERV_HAS_DOMAIN 16 /* server for one domain only */ 217#define SERV_FOR_NODOTS 32 /* server for names with no domain part only */ 218#define SERV_WARNED_RECURSIVE 64 /* avoid warning spam */ 219#define SERV_FROM_DBUS 128 /* 1 if source is DBus */ 220#define SERV_MARK 256 /* for mark-and-delete */ 221#define SERV_TYPE (SERV_HAS_DOMAIN | SERV_FOR_NODOTS) 222 223 224struct serverfd { 225 int fd; 226 union mysockaddr source_addr; 227 struct serverfd *next; 228}; 229 230struct server { 231 union mysockaddr addr, source_addr; 232 struct serverfd *sfd; /* non-NULL if this server has its own fd bound to 233 a source port */ 234 char *domain; /* set if this server only handles a domain. */ 235 int flags, tcpfd; 236 struct server *next; 237}; 238 239struct irec { 240 union mysockaddr addr; 241 struct in_addr netmask; /* only valid for IPv4 */ 242 struct irec *next; 243}; 244 245struct listener { 246 int fd, tcpfd, family; 247 struct irec *iface; /* only valid for non-wildcard */ 248 struct listener *next; 249}; 250 251/* interface and address parms from command line. */ 252struct iname { 253 char *name; 254 union mysockaddr addr; 255 int isloop, used; 256 struct iname *next; 257}; 258 259/* resolv-file parms from command-line */ 260struct resolvc { 261 struct resolvc *next; 262 int is_default, logged; 263 time_t mtime; 264 char *name; 265}; 266 267/* adn-hosts parms from command-line */ 268struct hostsfile { 269 struct hostsfile *next; 270 char *fname; 271 int index; /* matches to cache entries for logging */ 272}; 273 274struct frec { 275 union mysockaddr source; 276 struct all_addr dest; 277 struct server *sentto; 278 unsigned int iface; 279 unsigned short orig_id, new_id; 280 int fd, forwardall; 281 unsigned int crc; 282 time_t time; 283 struct frec *next; 284}; 285 286#define DHCP_CHADDR_MAX 16 287 288struct dhcp_lease { 289 int clid_len; /* length of client identifier */ 290 unsigned char *clid; /* clientid */ 291 char *hostname, *fqdn; /* name from client-hostname option or config */ 292 char auth_name; /* hostname came from config, not from client */ 293 char new; /* newly created */ 294 char changed; /* modified */ 295 char aux_changed; /* CLID or expiry changed */ 296 time_t expires; /* lease expiry */ 297#ifdef HAVE_BROKEN_RTC 298 unsigned int length; 299#endif 300 int hwaddr_len, hwaddr_type; 301 unsigned char hwaddr[DHCP_CHADDR_MAX]; 302 struct in_addr addr; 303 struct dhcp_lease *next; 304}; 305 306struct dhcp_netid { 307 char *net; 308 struct dhcp_netid *next; 309}; 310 311struct dhcp_netid_list { 312 struct dhcp_netid *list; 313 struct dhcp_netid_list *next; 314}; 315struct dhcp_config { 316 unsigned int flags; 317 int clid_len; /* length of client identifier */ 318 unsigned char *clid; /* clientid */ 319 int hwaddr_len, hwaddr_type; 320 unsigned char hwaddr[DHCP_CHADDR_MAX]; 321 char *hostname; 322 struct dhcp_netid netid; 323 struct in_addr addr; 324 time_t decline_time; 325 unsigned int lease_time, wildcard_mask; 326 struct dhcp_config *next; 327}; 328 329#define CONFIG_DISABLE 1 330#define CONFIG_CLID 2 331#define CONFIG_HWADDR 4 332#define CONFIG_TIME 8 333#define CONFIG_NAME 16 334#define CONFIG_ADDR 32 335#define CONFIG_NETID 64 336#define CONFIG_NOCLID 128 337#define CONFIG_FROM_ETHERS 256 /* entry created by /etc/ethers */ 338#define CONFIG_ADDR_HOSTS 512 /* address added by from /etc/hosts */ 339#define CONFIG_DECLINED 1024 /* address declined by client */ 340 341struct dhcp_opt { 342 int opt, len, flags; 343 unsigned char *val, *vendor_class; 344 struct dhcp_netid *netid; 345 struct dhcp_opt *next; 346}; 347 348#define DHOPT_ADDR 1 349#define DHOPT_STRING 2 350 351struct dhcp_boot { 352 char *file, *sname; 353 struct in_addr next_server; 354 struct dhcp_netid *netid; 355 struct dhcp_boot *next; 356}; 357 358struct dhcp_vendor { 359 int len, is_vendor; 360 char *data; 361 struct dhcp_netid netid; 362 struct dhcp_vendor *next; 363}; 364 365struct dhcp_mac { 366 unsigned int mask; 367 int hwaddr_len, hwaddr_type; 368 unsigned char hwaddr[DHCP_CHADDR_MAX]; 369 struct dhcp_netid netid; 370 struct dhcp_mac *next; 371}; 372 373struct dhcp_context { 374 unsigned int lease_time, addr_epoch; 375 struct in_addr netmask, broadcast; 376 struct in_addr local, router; 377 struct in_addr start, end; /* range of available addresses */ 378 int flags; 379 struct dhcp_netid netid, *filter; 380 struct dhcp_context *next, *current; 381}; 382 383#define CONTEXT_STATIC 1 384#define CONTEXT_NETMASK 2 385#define CONTEXT_BRDCAST 4 386 387 388typedef unsigned char u8; 389typedef unsigned short u16; 390typedef unsigned int u32; 391 392 393struct dhcp_packet { 394 u8 op, htype, hlen, hops; 395 u32 xid; 396 u16 secs, flags; 397 struct in_addr ciaddr, yiaddr, siaddr, giaddr; 398 u8 chaddr[DHCP_CHADDR_MAX], sname[64], file[128]; 399 u8 options[312]; 400}; 401 402struct ping_result { 403 struct in_addr addr; 404 time_t time; 405 struct ping_result *next; 406}; 407 408struct daemon { 409 /* datastuctures representing the command-line and 410 config file arguments. All set (including defaults) 411 in option.c */ 412 413 unsigned int options; 414 struct resolvc default_resolv, *resolv_files; 415 struct mx_srv_record *mxnames; 416 struct txt_record *txt; 417 char *mxtarget; 418 char *lease_file; 419 char *username, *groupname; 420 char *domain_suffix; 421 char *runfile; 422 char *lease_change_command; 423 struct iname *if_names, *if_addrs, *if_except, *dhcp_except; 424 struct bogus_addr *bogus_addr; 425 struct server *servers; 426 int log_fac; /* log facility */ 427 int cachesize, ftabsize; 428 int port, query_port; 429 unsigned long local_ttl; 430 struct hostsfile *addn_hosts; 431 struct dhcp_context *dhcp; 432 struct dhcp_config *dhcp_conf; 433 struct dhcp_opt *dhcp_opts, *vendor_opts; 434 struct dhcp_vendor *dhcp_vendors; 435 struct dhcp_mac *dhcp_macs; 436 struct dhcp_boot *boot_config; 437 struct dhcp_netid_list *dhcp_ignore; 438 int dhcp_max; 439 unsigned int min_leasetime; 440 struct doctor *doctors; 441 unsigned short edns_pktsz; 442 443 /* globally used stuff for DNS */ 444 char *packet; /* packet buffer */ 445 int packet_buff_sz; /* size of above */ 446 char *namebuff; /* MAXDNAME size buffer */ 447 struct serverfd *sfds; 448 struct irec *interfaces; 449 struct listener *listeners; 450 struct server *last_server; 451 struct server *srv_save; /* Used for resend on DoD */ 452 size_t packet_len; /* " " */ 453 pid_t script_pid, tcp_pids[MAX_PROCS]; 454 int num_kids; 455 456 /* DHCP state */ 457 int dhcpfd; 458#ifdef HAVE_LINUX_NETWORK 459 int netlinkfd; 460#else 461 int dhcp_raw_fd, dhcp_icmp_fd; 462#endif 463 struct iovec dhcp_packet; 464 char *dhcp_buff, *dhcp_buff2; 465 struct ping_result *ping_results; 466 FILE *lease_stream; 467 468 /* DBus stuff */ 469#ifdef HAVE_DBUS 470 /* void * here to avoid depending on dbus headers outside dbus.c */ 471 void *dbus; 472 struct watch *watches; 473#endif 474 475}; 476 477/* cache.c */ 478void cache_init(int cachesize, int log); 479void log_query(unsigned short flags, char *name, struct all_addr *addr, 480 unsigned short type, struct hostsfile *addn_hosts, int index); 481struct crec *cache_find_by_addr(struct crec *crecp, 482 struct all_addr *addr, time_t now, 483 unsigned short prot); 484struct crec *cache_find_by_name(struct crec *crecp, 485 char *name, time_t now, unsigned short prot); 486void cache_end_insert(void); 487void cache_start_insert(void); 488struct crec *cache_insert(char *name, struct all_addr *addr, 489 time_t now, unsigned long ttl, unsigned short flags); 490void cache_reload(int opts, char *buff, char *domain_suffix, struct hostsfile *addn_hosts); 491void cache_add_dhcp_entry(struct daemon *daemon, char *host_name, struct in_addr *host_address, time_t ttd); 492void cache_unhash_dhcp(void); 493void dump_cache(struct daemon *daemon, time_t now); 494char *cache_get_name(struct crec *crecp); 495 496/* rfc1035.c */ 497unsigned short extract_request(HEADER *header, size_t qlen, 498 char *name, unsigned short *typep); 499size_t setup_reply(HEADER *header, size_t qlen, 500 struct all_addr *addrp, unsigned short flags, 501 unsigned long local_ttl); 502void extract_addresses(HEADER *header, size_t qlen, char *namebuff, 503 time_t now, struct daemon *daemon); 504size_t answer_request(HEADER *header, char *limit, size_t qlen, struct daemon *daemon, 505 struct in_addr local_addr, struct in_addr local_netmask, time_t now); 506int check_for_bogus_wildcard(HEADER *header, size_t qlen, char *name, 507 struct bogus_addr *addr, time_t now); 508unsigned char *find_pseudoheader(HEADER *header, size_t plen, 509 size_t *len, unsigned char **p); 510int check_for_local_domain(char *name, time_t now, struct daemon *daemon); 511unsigned int questions_crc(HEADER *header, size_t plen, char *buff); 512size_t resize_packet(HEADER *header, size_t plen, 513 unsigned char *pheader, size_t hlen); 514 515/* util.c */ 516unsigned short rand16(void); 517int legal_char(char c); 518int canonicalise(char *s); 519unsigned char *do_rfc1035_name(unsigned char *p, char *sval); 520void die(char *message, char *arg1); 521void complain(char *message, int lineno, char *file); 522void *safe_malloc(size_t size); 523int sa_len(union mysockaddr *addr); 524int sockaddr_isequal(union mysockaddr *s1, union mysockaddr *s2); 525int hostname_isequal(char *a, char *b); 526time_t dnsmasq_time(void); 527int is_same_net(struct in_addr a, struct in_addr b, struct in_addr mask); 528int retry_send(void); 529void prettyprint_time(char *buf, unsigned int t); 530int prettyprint_addr(union mysockaddr *addr, char *buf); 531int parse_hex(char *in, unsigned char *out, int maxlen, 532 unsigned int *wildcard_mask, int *mac_type); 533int memcmp_masked(unsigned char *a, unsigned char *b, int len, 534 unsigned int mask); 535int expand_buf(struct iovec *iov, size_t size); 536char *print_mac(struct daemon *daemon, unsigned char *mac, int len); 537 538/* option.c */ 539struct daemon *read_opts (int argc, char **argv, char *compile_opts); 540 541/* forward.c */ 542void reply_query(struct serverfd *sfd, struct daemon *daemon, time_t now); 543void receive_query(struct listener *listen, struct daemon *daemon, time_t now); 544unsigned char *tcp_request(struct daemon *daemon, int confd, time_t now, 545 struct in_addr local_addr, struct in_addr netmask); 546void server_gone(struct daemon *daemon, struct server *server); 547 548/* network.c */ 549struct serverfd *allocate_sfd(union mysockaddr *addr, struct serverfd **sfds); 550int reload_servers(char *fname, struct daemon *daemon); 551void check_servers(struct daemon *daemon); 552int enumerate_interfaces(struct daemon *daemon); 553struct listener *create_wildcard_listeners(int port); 554struct listener *create_bound_listeners(struct daemon *daemon); 555int iface_check(struct daemon *daemon, int family, 556 struct all_addr *addr, char *name); 557int fix_fd(int fd); 558 559/* dhcp.c */ 560void dhcp_init(struct daemon *daemon); 561void dhcp_packet(struct daemon *daemon, time_t now); 562 563struct dhcp_context *address_available(struct dhcp_context *context, struct in_addr addr); 564struct dhcp_context *narrow_context(struct dhcp_context *context, struct in_addr taddr); 565int match_netid(struct dhcp_netid *check, struct dhcp_netid *pool, int negonly); 566int address_allocate(struct dhcp_context *context, struct daemon *daemon, 567 struct in_addr *addrp, unsigned char *hwaddr, int hw_len, 568 struct dhcp_netid *netids, time_t now); 569struct dhcp_config *find_config(struct dhcp_config *configs, 570 struct dhcp_context *context, 571 unsigned char *clid, int clid_len, 572 unsigned char *hwaddr, int hw_len, 573 int hw_type, char *hostname); 574void dhcp_update_configs(struct dhcp_config *configs); 575void dhcp_read_ethers(struct daemon *daemon); 576struct dhcp_config *config_find_by_address(struct dhcp_config *configs, struct in_addr addr); 577char *strip_hostname(struct daemon *daemon, char *hostname); 578char *host_from_dns(struct daemon *daemon, struct in_addr addr); 579 580/* lease.c */ 581void lease_update_file(struct daemon *daemon, time_t now); 582void lease_update_dns(struct daemon *daemon); 583void lease_init(struct daemon *daemon, time_t now); 584struct dhcp_lease *lease_allocate(struct in_addr addr); 585void lease_set_hwaddr(struct dhcp_lease *lease, unsigned char *hwaddr, 586 unsigned char *clid, int hw_len, int hw_type, int clid_len); 587void lease_set_hostname(struct dhcp_lease *lease, char *name, 588 char *suffix, int auth); 589void lease_set_expires(struct dhcp_lease *lease, unsigned int len, time_t now); 590struct dhcp_lease *lease_find_by_client(unsigned char *hwaddr, int hw_len, int hw_type, 591 unsigned char *clid, int clid_len); 592struct dhcp_lease *lease_find_by_addr(struct in_addr addr); 593void lease_prune(struct dhcp_lease *target, time_t now); 594void lease_update_from_configs(struct daemon *daemon); 595void lease_collect(struct daemon *daemon); 596 597/* rfc2131.c */ 598size_t dhcp_reply(struct daemon *daemon, struct dhcp_context *context, char *iface_name, size_t sz, time_t now, int unicast_dest); 599 600/* dnsmasq.c */ 601int make_icmp_sock(void); 602int icmp_ping(struct daemon *daemon, struct in_addr addr); 603void clear_cache_and_reload(struct daemon *daemon, time_t now); 604 605/* isc.c */ 606#ifdef HAVE_ISC_READER 607void load_dhcp(struct daemon *daemon, time_t now); 608#endif 609 610/* netlink.c */ 611#ifdef HAVE_LINUX_NETWORK 612void netlink_init(struct daemon *daemon); 613int iface_enumerate(struct daemon *daemon, void *parm, 614 int (*ipv4_callback)(), int (*ipv6_callback)()); 615void netlink_multicast(struct daemon *daemon); 616#endif 617 618/* bpf.c */ 619#ifndef HAVE_LINUX_NETWORK 620void init_bpf(struct daemon *daemon); 621void send_via_bpf(struct daemon *daemon, struct dhcp_packet *mess, size_t len, 622 struct in_addr iface_addr, struct ifreq *ifr); 623int iface_enumerate(struct daemon *daemon, void *parm, 624 int (*ipv4_callback)(), int (*ipv6_callback)()); 625#endif 626 627/* dbus.c */ 628#ifdef HAVE_DBUS 629char *dbus_init(struct daemon *daemon); 630void check_dbus_listeners(struct daemon *daemon, 631 fd_set *rset, fd_set *wset, fd_set *eset); 632int set_dbus_listeners(struct daemon *daemon, int maxfd, 633 fd_set *rset, fd_set *wset, fd_set *eset); 634#endif 635