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" 46 struct listen_list; 47 struct config_file; 48 struct addrinfo; 49 struct sldns_buffer; 50 struct tcl_list; 51 52 /** 53 * Listening for queries structure. 54 * Contains list of query-listen sockets. 55 */ 56 struct 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 */ 73 struct 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 */ 83 enum 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 */ 105 struct 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 */ 125 struct listen_port* listening_ports_open(struct config_file* cfg, 126 int* reuseport); 127 128 /** 129 * Close and delete the (list of) listening ports. 130 */ 131 void 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 */ 150 struct 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 */ 160 void 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 */ 167 void 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 */ 174 size_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 */ 180 void listen_stop_accept(struct listen_dnsport* listen); 181 182 /** 183 * start accept handlers for TCP (was stopped before) 184 * @param listen: listening structure. 185 */ 186 void 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 */ 210 int 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 */ 227 int 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 */ 238 int create_local_accept_sock(const char* path, int* noproto, int use_systemd); 239 240 #endif /* LISTEN_DNSPORT_H */ 241