listen_dnsport.h revision 356345
1/* 2 * services/listen_dnsport.h - listen on port 53 for incoming DNS queries. 3 * 4 * Copyright (c) 2007, NLnet Labs. All rights reserved. 5 * 6 * This software is open source. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * Redistributions of source code must retain the above copyright notice, 13 * this list of conditions and the following disclaimer. 14 * 15 * Redistributions in binary form must reproduce the above copyright notice, 16 * this list of conditions and the following disclaimer in the documentation 17 * and/or other materials provided with the distribution. 18 * 19 * Neither the name of the NLNET LABS nor the names of its contributors may 20 * be used to endorse or promote products derived from this software without 21 * specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36/** 37 * \file 38 * 39 * This file has functions to get queries from clients. 40 */ 41 42#ifndef LISTEN_DNSPORT_H 43#define LISTEN_DNSPORT_H 44 45#include "util/netevent.h" 46struct listen_list; 47struct config_file; 48struct addrinfo; 49struct sldns_buffer; 50struct tcl_list; 51 52/** 53 * Listening for queries structure. 54 * Contains list of query-listen sockets. 55 */ 56struct listen_dnsport { 57 /** Base for select calls */ 58 struct comm_base* base; 59 60 /** buffer shared by UDP connections, since there is only one 61 datagram at any time. */ 62 struct sldns_buffer* udp_buff; 63#ifdef USE_DNSCRYPT 64 struct sldns_buffer* dnscrypt_udp_buff; 65#endif 66 /** list of comm points used to get incoming events */ 67 struct listen_list* cps; 68}; 69 70/** 71 * Single linked list to store event points. 72 */ 73struct listen_list { 74 /** next in list */ 75 struct listen_list* next; 76 /** event info */ 77 struct comm_point* com; 78}; 79 80/** 81 * type of ports 82 */ 83enum listen_type { 84 /** udp type */ 85 listen_type_udp, 86 /** tcp type */ 87 listen_type_tcp, 88 /** udp ipv6 (v4mapped) for use with ancillary data */ 89 listen_type_udpancil, 90 /** ssl over tcp type */ 91 listen_type_ssl, 92 /** udp type + dnscrypt*/ 93 listen_type_udp_dnscrypt, 94 /** tcp type + dnscrypt */ 95 listen_type_tcp_dnscrypt, 96 /** udp ipv6 (v4mapped) for use with ancillary data + dnscrypt*/ 97 listen_type_udpancil_dnscrypt 98 99}; 100 101/** 102 * Single linked list to store shared ports that have been 103 * opened for use by all threads. 104 */ 105struct listen_port { 106 /** next in list */ 107 struct listen_port* next; 108 /** file descriptor, open and ready for use */ 109 int fd; 110 /** type of file descriptor, udp or tcp */ 111 enum listen_type ftype; 112}; 113 114/** 115 * Create shared listening ports 116 * Getaddrinfo, create socket, bind and listen to zero or more 117 * interfaces for IP4 and/or IP6, for UDP and/or TCP. 118 * On the given port number. It creates the sockets. 119 * @param cfg: settings on what ports to open. 120 * @param reuseport: set to true if you want reuseport, or NULL to not have it, 121 * set to false on exit if reuseport failed to apply (because of no 122 * kernel support). 123 * @return: linked list of ports or NULL on error. 124 */ 125struct listen_port* listening_ports_open(struct config_file* cfg, 126 int* reuseport); 127 128/** 129 * Close and delete the (list of) listening ports. 130 */ 131void listening_ports_free(struct listen_port* list); 132 133/** 134 * Create commpoints with for this thread for the shared ports. 135 * @param base: the comm_base that provides event functionality. 136 * for default all ifs. 137 * @param ports: the list of shared ports. 138 * @param bufsize: size of datagram buffer. 139 * @param tcp_accept_count: max number of simultaneous TCP connections 140 * from clients. 141 * @param tcp_idle_timeout: idle timeout for TCP connections in msec. 142 * @param tcp_conn_limit: TCP connection limit info. 143 * @param sslctx: nonNULL if ssl context. 144 * @param dtenv: nonNULL if dnstap enabled. 145 * @param cb: callback function when a request arrives. It is passed 146 * the packet and user argument. Return true to send a reply. 147 * @param cb_arg: user data argument for callback function. 148 * @return: the malloced listening structure, ready for use. NULL on error. 149 */ 150struct listen_dnsport* listen_create(struct comm_base* base, 151 struct listen_port* ports, size_t bufsize, 152 int tcp_accept_count, int tcp_idle_timeout, 153 struct tcl_list* tcp_conn_limit, void* sslctx, 154 struct dt_env *dtenv, comm_point_callback_type* cb, void* cb_arg); 155 156/** 157 * delete the listening structure 158 * @param listen: listening structure. 159 */ 160void listen_delete(struct listen_dnsport* listen); 161 162/** 163 * delete listen_list of commpoints. Calls commpointdelete() on items. 164 * This may close the fds or not depending on flags. 165 * @param list: to delete. 166 */ 167void listen_list_delete(struct listen_list* list); 168 169/** 170 * get memory size used by the listening structs 171 * @param listen: listening structure. 172 * @return: size in bytes. 173 */ 174size_t listen_get_mem(struct listen_dnsport* listen); 175 176/** 177 * stop accept handlers for TCP (until enabled again) 178 * @param listen: listening structure. 179 */ 180void listen_stop_accept(struct listen_dnsport* listen); 181 182/** 183 * start accept handlers for TCP (was stopped before) 184 * @param listen: listening structure. 185 */ 186void listen_start_accept(struct listen_dnsport* listen); 187 188/** 189 * Create and bind nonblocking UDP socket 190 * @param family: for socket call. 191 * @param socktype: for socket call. 192 * @param addr: for bind call. 193 * @param addrlen: for bind call. 194 * @param v6only: if enabled, IP6 sockets get IP6ONLY option set. 195 * if enabled with value 2 IP6ONLY option is disabled. 196 * @param inuse: on error, this is set true if the port was in use. 197 * @param noproto: on error, this is set true if cause is that the 198 IPv6 proto (family) is not available. 199 * @param rcv: set size on rcvbuf with socket option, if 0 it is not set. 200 * @param snd: set size on sndbuf with socket option, if 0 it is not set. 201 * @param listen: if true, this is a listening UDP port, eg port 53, and 202 * set SO_REUSEADDR on it. 203 * @param reuseport: if nonNULL and true, try to set SO_REUSEPORT on 204 * listening UDP port. Set to false on return if it failed to do so. 205 * @param transparent: set IP_TRANSPARENT socket option. 206 * @param freebind: set IP_FREEBIND socket option. 207 * @param use_systemd: if true, fetch sockets from systemd. 208 * @return: the socket. -1 on error. 209 */ 210int create_udp_sock(int family, int socktype, struct sockaddr* addr, 211 socklen_t addrlen, int v6only, int* inuse, int* noproto, int rcv, 212 int snd, int listen, int* reuseport, int transparent, int freebind, int use_systemd); 213 214/** 215 * Create and bind TCP listening socket 216 * @param addr: address info ready to make socket. 217 * @param v6only: enable ip6 only flag on ip6 sockets. 218 * @param noproto: if error caused by lack of protocol support. 219 * @param reuseport: if nonNULL and true, try to set SO_REUSEPORT on 220 * listening UDP port. Set to false on return if it failed to do so. 221 * @param transparent: set IP_TRANSPARENT socket option. 222 * @param mss: maximum segment size of the socket. if zero, leaves the default. 223 * @param freebind: set IP_FREEBIND socket option. 224 * @param use_systemd: if true, fetch sockets from systemd. 225 * @return: the socket. -1 on error. 226 */ 227int create_tcp_accept_sock(struct addrinfo *addr, int v6only, int* noproto, 228 int* reuseport, int transparent, int mss, int freebind, int use_systemd); 229 230/** 231 * Create and bind local listening socket 232 * @param path: path to the socket. 233 * @param noproto: on error, this is set true if cause is that local sockets 234 * are not supported. 235 * @param use_systemd: if true, fetch sockets from systemd. 236 * @return: the socket. -1 on error. 237 */ 238int create_local_accept_sock(const char* path, int* noproto, int use_systemd); 239 240/** 241 * TCP request info. List of requests outstanding on the channel, that 242 * are asked for but not yet answered back. 243 */ 244struct tcp_req_info { 245 /** the TCP comm point for this. Its buffer is used for read/write */ 246 struct comm_point* cp; 247 /** the buffer to use to spool reply from mesh into, 248 * it can then be copied to the result list and written. 249 * it is a pointer to the shared udp buffer. */ 250 struct sldns_buffer* spool_buffer; 251 /** are we in worker_handle function call (for recursion callback)*/ 252 int in_worker_handle; 253 /** is the comm point dropped (by worker handle). 254 * That means we have to disconnect the channel. */ 255 int is_drop; 256 /** is the comm point set to send_reply (by mesh new client in worker 257 * handle), if so answer is available in c.buffer */ 258 int is_reply; 259 /** read channel has closed, just write pending results */ 260 int read_is_closed; 261 /** read again */ 262 int read_again; 263 /** number of outstanding requests */ 264 int num_open_req; 265 /** list of outstanding requests */ 266 struct tcp_req_open_item* open_req_list; 267 /** number of pending writeable results */ 268 int num_done_req; 269 /** list of pending writable result packets, malloced one at a time */ 270 struct tcp_req_done_item* done_req_list; 271}; 272 273/** 274 * List of open items in TCP channel 275 */ 276struct tcp_req_open_item { 277 /** next in list */ 278 struct tcp_req_open_item* next; 279 /** the mesh area of the mesh_state */ 280 struct mesh_area* mesh; 281 /** the mesh state */ 282 struct mesh_state* mesh_state; 283}; 284 285/** 286 * List of done items in TCP channel 287 */ 288struct tcp_req_done_item { 289 /** next in list */ 290 struct tcp_req_done_item* next; 291 /** the buffer with packet contents */ 292 uint8_t* buf; 293 /** length of the buffer */ 294 size_t len; 295}; 296 297/** 298 * Create tcp request info structure that keeps track of open 299 * requests on the TCP channel that are resolved at the same time, 300 * and the pending results that have to get written back to that client. 301 * @param spoolbuf: shared buffer 302 * @return new structure or NULL on alloc failure. 303 */ 304struct tcp_req_info* tcp_req_info_create(struct sldns_buffer* spoolbuf); 305 306/** 307 * Delete tcp request structure. Called by owning commpoint. 308 * Removes mesh entry references and stored results from the lists. 309 * @param req: the tcp request info 310 */ 311void tcp_req_info_delete(struct tcp_req_info* req); 312 313/** 314 * Clear tcp request structure. Removes list entries, sets it up ready 315 * for the next connection. 316 * @param req: tcp request info structure. 317 */ 318void tcp_req_info_clear(struct tcp_req_info* req); 319 320/** 321 * Remove mesh state entry from list in tcp_req_info. 322 * caller has to manage the mesh state reply entry in the mesh state. 323 * @param req: the tcp req info that has the entry removed from the list. 324 * @param m: the state removed from the list. 325 */ 326void tcp_req_info_remove_mesh_state(struct tcp_req_info* req, 327 struct mesh_state* m); 328 329/** 330 * Handle write done of the last result packet 331 * @param req: the tcp req info. 332 */ 333void tcp_req_info_handle_writedone(struct tcp_req_info* req); 334 335/** 336 * Handle read done of a new request from the client 337 * @param req: the tcp req info. 338 */ 339void tcp_req_info_handle_readdone(struct tcp_req_info* req); 340 341/** 342 * Add mesh state to the tcp req list of open requests. 343 * So the comm_reply can be removed off the mesh reply list when 344 * the tcp channel has to be closed (for other reasons then that that 345 * request was done, eg. channel closed by client or some format error). 346 * @param req: tcp req info structure. It keeps track of the simultaneous 347 * requests and results on a tcp (or TLS) channel. 348 * @param mesh: mesh area for the state. 349 * @param m: mesh state to add. 350 * @return 0 on failure (malloc failure). 351 */ 352int tcp_req_info_add_meshstate(struct tcp_req_info* req, 353 struct mesh_area* mesh, struct mesh_state* m); 354 355/** 356 * Send reply on tcp simultaneous answer channel. May queue it up. 357 * @param req: request info structure. 358 */ 359void tcp_req_info_send_reply(struct tcp_req_info* req); 360 361/** the read channel has closed 362 * @param req: request. remaining queries are looked up and answered. 363 * @return zero if nothing to do, just close the tcp. 364 */ 365int tcp_req_info_handle_read_close(struct tcp_req_info* req); 366 367/** get the size of currently used tcp stream wait buffers (in bytes) */ 368size_t tcp_req_info_get_stream_buffer_size(void); 369 370#endif /* LISTEN_DNSPORT_H */ 371