listen_dnsport.h revision 269257 
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;
50
51/**
52 * Listening for queries structure.
53 * Contains list of query-listen sockets.
54 */
55struct listen_dnsport {
56	/** Base for select calls */
57	struct comm_base* base;
58
59	/** buffer shared by UDP connections, since there is only one
60	    datagram at any time. */
61	struct sldns_buffer* udp_buff;
62
63	/** list of comm points used to get incoming events */
64	struct listen_list* cps;
65};
66
67/**
68 * Single linked list to store event points.
69 */
70struct listen_list {
71	/** next in list */
72	struct listen_list* next;
73	/** event info */
74	struct comm_point* com;
75};
76
77/**
78 * type of ports
79 */
80enum listen_type {
81	/** udp type */
82	listen_type_udp,
83	/** tcp type */
84	listen_type_tcp,
85	/** udp ipv6 (v4mapped) for use with ancillary data */
86	listen_type_udpancil,
87	/** ssl over tcp type */
88	listen_type_ssl
89};
90
91/**
92 * Single linked list to store shared ports that have been
93 * opened for use by all threads.
94 */
95struct listen_port {
96	/** next in list */
97	struct listen_port* next;
98	/** file descriptor, open and ready for use */
99	int fd;
100	/** type of file descriptor, udp or tcp */
101	enum listen_type ftype;
102};
103
104/**
105 * Create shared listening ports
106 * Getaddrinfo, create socket, bind and listen to zero or more
107 * interfaces for IP4 and/or IP6, for UDP and/or TCP.
108 * On the given port number. It creates the sockets.
109 * @param cfg: settings on what ports to open.
110 * @param reuseport: set to true if you want reuseport, or NULL to not have it,
111 *   set to false on exit if reuseport failed to apply (because of no
112 *   kernel support).
113 * @return: linked list of ports or NULL on error.
114 */
115struct listen_port* listening_ports_open(struct config_file* cfg,
116	int* reuseport);
117
118/**
119 * Close and delete the (list of) listening ports.
120 */
121void listening_ports_free(struct listen_port* list);
122
123/**
124 * Create commpoints with for this thread for the shared ports.
125 * @param base: the comm_base that provides event functionality.
126 *	for default all ifs.
127 * @param ports: the list of shared ports.
128 * @param bufsize: size of datagram buffer.
129 * @param tcp_accept_count: max number of simultaneous TCP connections
130 * 	from clients.
131 * @param sslctx: nonNULL if ssl context.
132 * @param cb: callback function when a request arrives. It is passed
133 *	  the packet and user argument. Return true to send a reply.
134 * @param cb_arg: user data argument for callback function.
135 * @return: the malloced listening structure, ready for use. NULL on error.
136 */
137struct listen_dnsport* listen_create(struct comm_base* base,
138	struct listen_port* ports, size_t bufsize, int tcp_accept_count,
139	void* sslctx, comm_point_callback_t* cb, void* cb_arg);
140
141/**
142 * delete the listening structure
143 * @param listen: listening structure.
144 */
145void listen_delete(struct listen_dnsport* listen);
146
147/**
148 * delete listen_list of commpoints. Calls commpointdelete() on items.
149 * This may close the fds or not depending on flags.
150 * @param list: to delete.
151 */
152void listen_list_delete(struct listen_list* list);
153
154/**
155 * get memory size used by the listening structs
156 * @param listen: listening structure.
157 * @return: size in bytes.
158 */
159size_t listen_get_mem(struct listen_dnsport* listen);
160
161/**
162 * stop accept handlers for TCP (until enabled again)
163 * @param listen: listening structure.
164 */
165void listen_stop_accept(struct listen_dnsport* listen);
166
167/**
168 * start accept handlers for TCP (was stopped before)
169 * @param listen: listening structure.
170 */
171void listen_start_accept(struct listen_dnsport* listen);
172
173/**
174 * Create and bind nonblocking UDP socket
175 * @param family: for socket call.
176 * @param socktype: for socket call.
177 * @param addr: for bind call.
178 * @param addrlen: for bind call.
179 * @param v6only: if enabled, IP6 sockets get IP6ONLY option set.
180 * 	if enabled with value 2 IP6ONLY option is disabled.
181 * @param inuse: on error, this is set true if the port was in use.
182 * @param noproto: on error, this is set true if cause is that the
183	IPv6 proto (family) is not available.
184 * @param rcv: set size on rcvbuf with socket option, if 0 it is not set.
185 * @param snd: set size on sndbuf with socket option, if 0 it is not set.
186 * @param listen: if true, this is a listening UDP port, eg port 53, and
187 * 	set SO_REUSEADDR on it.
188 * @param reuseport: if nonNULL and true, try to set SO_REUSEPORT on
189 * 	listening UDP port.  Set to false on return if it failed to do so.
190 * @return: the socket. -1 on error.
191 */
192int create_udp_sock(int family, int socktype, struct sockaddr* addr,
193	socklen_t addrlen, int v6only, int* inuse, int* noproto, int rcv,
194	int snd, int listen, int* reuseport);
195
196/**
197 * Create and bind TCP listening socket
198 * @param addr: address info ready to make socket.
199 * @param v6only: enable ip6 only flag on ip6 sockets.
200 * @param noproto: if error caused by lack of protocol support.
201 * @param reuseport: if nonNULL and true, try to set SO_REUSEPORT on
202 * 	listening UDP port.  Set to false on return if it failed to do so.
203 * @return: the socket. -1 on error.
204 */
205int create_tcp_accept_sock(struct addrinfo *addr, int v6only, int* noproto,
206	int* reuseport);
207
208#endif /* LISTEN_DNSPORT_H */
209