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Emeric Brun3835c0d2020-07-07 09:46:09 +02001/*
Willy Tarreau2b5e0d82020-09-16 21:58:52 +02002 * UDP protocol layer on top of AF_INET/AF_INET6
Emeric Brun3835c0d2020-07-07 09:46:09 +02003 *
4 * Copyright 2019 HAProxy Technologies, Frédéric Lécaille <flecaille@haproxy.com>
5 *
6 * Partial merge by Emeric Brun <ebrun@haproxy.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 *
13 */
14
15#include <ctype.h>
16#include <errno.h>
17#include <fcntl.h>
18#include <stdio.h>
19#include <stdlib.h>
20#include <string.h>
21#include <time.h>
22
23#include <sys/param.h>
24#include <sys/socket.h>
25#include <sys/types.h>
26
27#include <netinet/udp.h>
28#include <netinet/in.h>
29
30#include <haproxy/fd.h>
31#include <haproxy/listener.h>
32#include <haproxy/log.h>
33#include <haproxy/namespace.h>
34#include <haproxy/port_range.h>
35#include <haproxy/protocol.h>
36#include <haproxy/proto_udp.h>
37#include <haproxy/proxy.h>
38#include <haproxy/server.h>
Willy Tarreau18b7df72020-08-28 12:07:22 +020039#include <haproxy/sock.h>
Willy Tarreauf1725582020-08-28 15:30:11 +020040#include <haproxy/sock_inet.h>
Emeric Brun3835c0d2020-07-07 09:46:09 +020041#include <haproxy/task.h>
42
Emeric Brun3835c0d2020-07-07 09:46:09 +020043static int udp_bind_listener(struct listener *listener, char *errmsg, int errlen);
Willy Tarreaucb66ea62020-09-25 17:12:32 +020044static int udp_suspend_receiver(struct receiver *rx);
Willy Tarreaue122dc52020-10-07 19:55:15 +020045static int udp_resume_receiver(struct receiver *rx);
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +020046static void udp_enable_listener(struct listener *listener);
47static void udp_disable_listener(struct listener *listener);
Emeric Brun3835c0d2020-07-07 09:46:09 +020048static void udp4_add_listener(struct listener *listener, int port);
49static void udp6_add_listener(struct listener *listener, int port);
50
51/* Note: must not be declared <const> as its list will be overwritten */
52static struct protocol proto_udp4 = {
53 .name = "udp4",
Willy Tarreaub0254cb2020-09-04 08:07:11 +020054 .fam = &proto_fam_inet4,
Willy Tarreaua54553f2020-09-16 17:50:45 +020055 .ctrl_type = SOCK_DGRAM,
Willy Tarreau2b5e0d82020-09-16 21:58:52 +020056 .sock_domain = AF_INET,
Emeric Brun3835c0d2020-07-07 09:46:09 +020057 .sock_type = SOCK_DGRAM,
58 .sock_prot = IPPROTO_UDP,
Emeric Brun3835c0d2020-07-07 09:46:09 +020059 .add = udp4_add_listener,
Willy Tarreaucb66ea62020-09-25 17:12:32 +020060 .listen = udp_bind_listener,
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +020061 .enable = udp_enable_listener,
62 .disable = udp_disable_listener,
Willy Tarreau7b2febd2020-10-09 17:18:29 +020063 .unbind = default_unbind_listener,
Willy Tarreaue03204c2020-10-09 17:02:21 +020064 .suspend = default_suspend_listener,
65 .resume = default_resume_listener,
Willy Tarreau686fa3d2020-09-25 19:09:53 +020066 .rx_enable = sock_enable,
67 .rx_disable = sock_disable,
Willy Tarreauf58b8db2020-10-09 16:32:08 +020068 .rx_unbind = sock_unbind,
Willy Tarreaucb66ea62020-09-25 17:12:32 +020069 .rx_suspend = udp_suspend_receiver,
Willy Tarreaue122dc52020-10-07 19:55:15 +020070 .rx_resume = udp_resume_receiver,
Willy Tarreaud7f331c2020-09-25 17:01:43 +020071 .receivers = LIST_HEAD_INIT(proto_udp4.receivers),
72 .nb_receivers = 0,
Emeric Brun3835c0d2020-07-07 09:46:09 +020073};
74
75INITCALL1(STG_REGISTER, protocol_register, &proto_udp4);
76
77/* Note: must not be declared <const> as its list will be overwritten */
78static struct protocol proto_udp6 = {
79 .name = "udp6",
Willy Tarreaub0254cb2020-09-04 08:07:11 +020080 .fam = &proto_fam_inet6,
Willy Tarreaua54553f2020-09-16 17:50:45 +020081 .ctrl_type = SOCK_DGRAM,
Willy Tarreau2b5e0d82020-09-16 21:58:52 +020082 .sock_domain = AF_INET6,
Emeric Brun3835c0d2020-07-07 09:46:09 +020083 .sock_type = SOCK_DGRAM,
84 .sock_prot = IPPROTO_UDP,
Emeric Brun3835c0d2020-07-07 09:46:09 +020085 .add = udp6_add_listener,
Willy Tarreaucb66ea62020-09-25 17:12:32 +020086 .listen = udp_bind_listener,
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +020087 .enable = udp_enable_listener,
88 .disable = udp_disable_listener,
Willy Tarreau7b2febd2020-10-09 17:18:29 +020089 .unbind = default_unbind_listener,
Willy Tarreaue03204c2020-10-09 17:02:21 +020090 .suspend = default_suspend_listener,
91 .resume = default_resume_listener,
Willy Tarreau686fa3d2020-09-25 19:09:53 +020092 .rx_enable = sock_enable,
93 .rx_disable = sock_disable,
Willy Tarreauf58b8db2020-10-09 16:32:08 +020094 .rx_unbind = sock_unbind,
Willy Tarreaucb66ea62020-09-25 17:12:32 +020095 .rx_suspend = udp_suspend_receiver,
Willy Tarreaue122dc52020-10-07 19:55:15 +020096 .rx_resume = udp_resume_receiver,
Willy Tarreaud7f331c2020-09-25 17:01:43 +020097 .receivers = LIST_HEAD_INIT(proto_udp6.receivers),
98 .nb_receivers = 0,
Emeric Brun3835c0d2020-07-07 09:46:09 +020099};
100
101INITCALL1(STG_REGISTER, protocol_register, &proto_udp6);
102
Emeric Brun3835c0d2020-07-07 09:46:09 +0200103/* This function tries to bind a UDPv4/v6 listener. It may return a warning or
104 * an error message in <errmsg> if the message is at most <errlen> bytes long
105 * (including '\0'). Note that <errmsg> may be NULL if <errlen> is also zero.
106 * The return value is composed from ERR_ABORT, ERR_WARN,
107 * ERR_ALERT, ERR_RETRYABLE and ERR_FATAL. ERR_NONE indicates that everything
108 * was alright and that no message was returned. ERR_RETRYABLE means that an
109 * error occurred but that it may vanish after a retry (eg: port in use), and
110 * ERR_FATAL indicates a non-fixable error. ERR_WARN and ERR_ALERT do not alter
111 * the meaning of the error, but just indicate that a message is present which
112 * should be displayed with the respective level. Last, ERR_ABORT indicates
113 * that it's pointless to try to start other listeners. No error message is
114 * returned if errlen is NULL.
115 */
116int udp_bind_listener(struct listener *listener, char *errmsg, int errlen)
117{
Willy Tarreau2f7687d2020-09-01 16:23:29 +0200118 int err = ERR_NONE;
Willy Tarreau2f7687d2020-09-01 16:23:29 +0200119 char *msg = NULL;
Emeric Brun3835c0d2020-07-07 09:46:09 +0200120
121 /* ensure we never return garbage */
122 if (errlen)
123 *errmsg = 0;
124
125 if (listener->state != LI_ASSIGNED)
126 return ERR_NONE; /* already bound */
127
Willy Tarreauad33acf2020-09-02 18:40:02 +0200128 if (!(listener->rx.flags & RX_F_BOUND)) {
129 msg = "receiving socket not bound";
Willy Tarreau2f7687d2020-09-01 16:23:29 +0200130 goto udp_return;
Emeric Brun3835c0d2020-07-07 09:46:09 +0200131 }
132
Willy Tarreaua37b2442020-09-24 07:23:45 +0200133 listener_set_state(listener, LI_LISTEN);
Emeric Brun3835c0d2020-07-07 09:46:09 +0200134
Emeric Brun3835c0d2020-07-07 09:46:09 +0200135 udp_return:
136 if (msg && errlen) {
137 char pn[INET6_ADDRSTRLEN];
138
Willy Tarreau2f7687d2020-09-01 16:23:29 +0200139 addr_to_str(&listener->rx.addr, pn, sizeof(pn));
140 snprintf(errmsg, errlen, "%s [%s:%d]", msg, pn, get_host_port(&listener->rx.addr));
Emeric Brun3835c0d2020-07-07 09:46:09 +0200141 }
142 return err;
Emeric Brun3835c0d2020-07-07 09:46:09 +0200143}
144
Emeric Brun3835c0d2020-07-07 09:46:09 +0200145/* Add <listener> to the list of udp4 listeners, on port <port>. The
146 * listener's state is automatically updated from LI_INIT to LI_ASSIGNED.
147 * The number of listeners for the protocol is updated.
148 */
149static void udp4_add_listener(struct listener *listener, int port)
150{
151 if (listener->state != LI_INIT)
152 return;
Willy Tarreaua37b2442020-09-24 07:23:45 +0200153 listener_set_state(listener, LI_ASSIGNED);
Willy Tarreaub7436612020-08-28 19:51:44 +0200154 listener->rx.proto = &proto_udp4;
Willy Tarreau37159062020-08-27 07:48:42 +0200155 ((struct sockaddr_in *)(&listener->rx.addr))->sin_port = htons(port);
Willy Tarreaud7f331c2020-09-25 17:01:43 +0200156 LIST_ADDQ(&proto_udp4.receivers, &listener->rx.proto_list);
157 proto_udp4.nb_receivers++;
Emeric Brun3835c0d2020-07-07 09:46:09 +0200158}
159
160/* Add <listener> to the list of udp6 listeners, on port <port>. The
161 * listener's state is automatically updated from LI_INIT to LI_ASSIGNED.
162 * The number of listeners for the protocol is updated.
163 */
164static void udp6_add_listener(struct listener *listener, int port)
165{
166 if (listener->state != LI_INIT)
167 return;
Willy Tarreaua37b2442020-09-24 07:23:45 +0200168 listener_set_state(listener, LI_ASSIGNED);
Willy Tarreaub7436612020-08-28 19:51:44 +0200169 listener->rx.proto = &proto_udp6;
Willy Tarreau7da02dd2020-12-04 14:28:23 +0100170 ((struct sockaddr_in6 *)(&listener->rx.addr))->sin6_port = htons(port);
Willy Tarreaud7f331c2020-09-25 17:01:43 +0200171 LIST_ADDQ(&proto_udp6.receivers, &listener->rx.proto_list);
172 proto_udp6.nb_receivers++;
Emeric Brun3835c0d2020-07-07 09:46:09 +0200173}
174
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +0200175/* Enable receipt of incoming connections for listener <l>. The receiver must
Willy Tarreaua4380b22020-11-04 13:59:04 +0100176 * still be valid.
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +0200177 */
178static void udp_enable_listener(struct listener *l)
179{
Willy Tarreaua4380b22020-11-04 13:59:04 +0100180 fd_want_recv_safe(l->rx.fd);
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +0200181}
182
183/* Disable receipt of incoming connections for listener <l>. The receiver must
Willy Tarreaua4380b22020-11-04 13:59:04 +0100184 * still be valid.
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +0200185 */
186static void udp_disable_listener(struct listener *l)
187{
Willy Tarreaua4380b22020-11-04 13:59:04 +0100188 fd_stop_recv(l->rx.fd);
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +0200189}
190
Willy Tarreaucb66ea62020-09-25 17:12:32 +0200191/* Suspend a receiver. Returns < 0 in case of failure, 0 if the receiver
192 * was totally stopped, or > 0 if correctly suspended.
Willy Tarreaue122dc52020-10-07 19:55:15 +0200193 * The principle is a bit ugly but works well, at least on Linux: in order to
194 * suspend the receiver, we want it to stop receiving traffic, which means that
195 * the socket must be unhashed from the kernel's socket table. The simple way
196 * to do this is to connect to any address that is reachable and will not be
197 * used by regular traffic, and a great one is reconnecting to self.
Emeric Brun3835c0d2020-07-07 09:46:09 +0200198 */
Willy Tarreaucb66ea62020-09-25 17:12:32 +0200199static int udp_suspend_receiver(struct receiver *rx)
Emeric Brun3835c0d2020-07-07 09:46:09 +0200200{
Willy Tarreaue122dc52020-10-07 19:55:15 +0200201 struct sockaddr_storage ss;
202 socklen_t len = sizeof(ss);
203
204 if (rx->fd < 0)
205 return 0;
206
Willy Tarreau59b5da42020-11-04 14:14:55 +0100207 /* we never do that with a shared FD otherwise we'd break it in the
208 * parent process and any possible subsequent worker inheriting it.
209 */
210 if (rx->flags & RX_F_INHERITED)
211 return -1;
212
Willy Tarreaue122dc52020-10-07 19:55:15 +0200213 if (getsockname(rx->fd, (struct sockaddr *)&ss, &len) < 0)
214 return -1;
215
216 if (connect(rx->fd, (struct sockaddr *)&ss, len) < 0)
217 return -1;
218
219 /* not necessary but may make debugging clearer */
220 fd_stop_recv(rx->fd);
221 return 1;
222}
223
224/* Resume a receiver. Returns < 0 in case of failure, 0 if the receiver
225 * was totally stopped, or > 0 if correctly suspended.
226 * The principle is to reverse the change above, we'll break the connection by
227 * connecting to AF_UNSPEC. The association breaks and the socket starts to
228 * receive from everywhere again.
229 */
230static int udp_resume_receiver(struct receiver *rx)
231{
Willy Tarreau2f6f3622020-10-14 10:50:41 +0200232 const struct sockaddr sa = { .sa_family = AF_UNSPEC };
Willy Tarreaue122dc52020-10-07 19:55:15 +0200233
234 if (rx->fd < 0)
235 return 0;
236
Willy Tarreau2f6f3622020-10-14 10:50:41 +0200237 if (connect(rx->fd, &sa, sizeof(sa)) < 0)
Willy Tarreaue122dc52020-10-07 19:55:15 +0200238 return -1;
239
240 fd_want_recv(rx->fd);
241 return 1;
Emeric Brun3835c0d2020-07-07 09:46:09 +0200242}
243
244/*
245 * Local variables:
246 * c-indent-level: 8
247 * c-basic-offset: 8
248 * End:
249 */