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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 +020048
49/* Note: must not be declared <const> as its list will be overwritten */
50static struct protocol proto_udp4 = {
51 .name = "udp4",
Willy Tarreaub0254cb2020-09-04 08:07:11 +020052 .fam = &proto_fam_inet4,
Willy Tarreaua54553f2020-09-16 17:50:45 +020053 .ctrl_type = SOCK_DGRAM,
Willy Tarreau2b5e0d82020-09-16 21:58:52 +020054 .sock_domain = AF_INET,
Emeric Brun3835c0d2020-07-07 09:46:09 +020055 .sock_type = SOCK_DGRAM,
56 .sock_prot = IPPROTO_UDP,
Willy Tarreauefcf1382020-12-04 15:03:36 +010057 .add = default_add_listener,
Willy Tarreaucb66ea62020-09-25 17:12:32 +020058 .listen = udp_bind_listener,
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +020059 .enable = udp_enable_listener,
60 .disable = udp_disable_listener,
Willy Tarreau7b2febd2020-10-09 17:18:29 +020061 .unbind = default_unbind_listener,
Willy Tarreaue03204c2020-10-09 17:02:21 +020062 .suspend = default_suspend_listener,
63 .resume = default_resume_listener,
Willy Tarreau686fa3d2020-09-25 19:09:53 +020064 .rx_enable = sock_enable,
65 .rx_disable = sock_disable,
Willy Tarreauf58b8db2020-10-09 16:32:08 +020066 .rx_unbind = sock_unbind,
Willy Tarreaucb66ea62020-09-25 17:12:32 +020067 .rx_suspend = udp_suspend_receiver,
Willy Tarreaue122dc52020-10-07 19:55:15 +020068 .rx_resume = udp_resume_receiver,
Willy Tarreaud7f331c2020-09-25 17:01:43 +020069 .receivers = LIST_HEAD_INIT(proto_udp4.receivers),
70 .nb_receivers = 0,
Emeric Brun3835c0d2020-07-07 09:46:09 +020071};
72
73INITCALL1(STG_REGISTER, protocol_register, &proto_udp4);
74
75/* Note: must not be declared <const> as its list will be overwritten */
76static struct protocol proto_udp6 = {
77 .name = "udp6",
Willy Tarreaub0254cb2020-09-04 08:07:11 +020078 .fam = &proto_fam_inet6,
Willy Tarreaua54553f2020-09-16 17:50:45 +020079 .ctrl_type = SOCK_DGRAM,
Willy Tarreau2b5e0d82020-09-16 21:58:52 +020080 .sock_domain = AF_INET6,
Emeric Brun3835c0d2020-07-07 09:46:09 +020081 .sock_type = SOCK_DGRAM,
82 .sock_prot = IPPROTO_UDP,
Willy Tarreauefcf1382020-12-04 15:03:36 +010083 .add = default_add_listener,
Willy Tarreaucb66ea62020-09-25 17:12:32 +020084 .listen = udp_bind_listener,
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +020085 .enable = udp_enable_listener,
86 .disable = udp_disable_listener,
Willy Tarreau7b2febd2020-10-09 17:18:29 +020087 .unbind = default_unbind_listener,
Willy Tarreaue03204c2020-10-09 17:02:21 +020088 .suspend = default_suspend_listener,
89 .resume = default_resume_listener,
Willy Tarreau686fa3d2020-09-25 19:09:53 +020090 .rx_enable = sock_enable,
91 .rx_disable = sock_disable,
Willy Tarreauf58b8db2020-10-09 16:32:08 +020092 .rx_unbind = sock_unbind,
Willy Tarreaucb66ea62020-09-25 17:12:32 +020093 .rx_suspend = udp_suspend_receiver,
Willy Tarreaue122dc52020-10-07 19:55:15 +020094 .rx_resume = udp_resume_receiver,
Willy Tarreaud7f331c2020-09-25 17:01:43 +020095 .receivers = LIST_HEAD_INIT(proto_udp6.receivers),
96 .nb_receivers = 0,
Emeric Brun3835c0d2020-07-07 09:46:09 +020097};
98
99INITCALL1(STG_REGISTER, protocol_register, &proto_udp6);
100
Emeric Brun3835c0d2020-07-07 09:46:09 +0200101/* This function tries to bind a UDPv4/v6 listener. It may return a warning or
102 * an error message in <errmsg> if the message is at most <errlen> bytes long
103 * (including '\0'). Note that <errmsg> may be NULL if <errlen> is also zero.
104 * The return value is composed from ERR_ABORT, ERR_WARN,
105 * ERR_ALERT, ERR_RETRYABLE and ERR_FATAL. ERR_NONE indicates that everything
106 * was alright and that no message was returned. ERR_RETRYABLE means that an
107 * error occurred but that it may vanish after a retry (eg: port in use), and
108 * ERR_FATAL indicates a non-fixable error. ERR_WARN and ERR_ALERT do not alter
109 * the meaning of the error, but just indicate that a message is present which
110 * should be displayed with the respective level. Last, ERR_ABORT indicates
111 * that it's pointless to try to start other listeners. No error message is
112 * returned if errlen is NULL.
113 */
114int udp_bind_listener(struct listener *listener, char *errmsg, int errlen)
115{
Willy Tarreau2f7687d2020-09-01 16:23:29 +0200116 int err = ERR_NONE;
Willy Tarreau2f7687d2020-09-01 16:23:29 +0200117 char *msg = NULL;
Emeric Brun3835c0d2020-07-07 09:46:09 +0200118
119 /* ensure we never return garbage */
120 if (errlen)
121 *errmsg = 0;
122
123 if (listener->state != LI_ASSIGNED)
124 return ERR_NONE; /* already bound */
125
Willy Tarreauad33acf2020-09-02 18:40:02 +0200126 if (!(listener->rx.flags & RX_F_BOUND)) {
127 msg = "receiving socket not bound";
Willy Tarreau2f7687d2020-09-01 16:23:29 +0200128 goto udp_return;
Emeric Brun3835c0d2020-07-07 09:46:09 +0200129 }
130
Willy Tarreaua37b2442020-09-24 07:23:45 +0200131 listener_set_state(listener, LI_LISTEN);
Emeric Brun3835c0d2020-07-07 09:46:09 +0200132
Emeric Brun3835c0d2020-07-07 09:46:09 +0200133 udp_return:
134 if (msg && errlen) {
135 char pn[INET6_ADDRSTRLEN];
136
Willy Tarreau2f7687d2020-09-01 16:23:29 +0200137 addr_to_str(&listener->rx.addr, pn, sizeof(pn));
138 snprintf(errmsg, errlen, "%s [%s:%d]", msg, pn, get_host_port(&listener->rx.addr));
Emeric Brun3835c0d2020-07-07 09:46:09 +0200139 }
140 return err;
Emeric Brun3835c0d2020-07-07 09:46:09 +0200141}
142
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +0200143/* Enable receipt of incoming connections for listener <l>. The receiver must
Willy Tarreaua4380b22020-11-04 13:59:04 +0100144 * still be valid.
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +0200145 */
146static void udp_enable_listener(struct listener *l)
147{
Willy Tarreaua4380b22020-11-04 13:59:04 +0100148 fd_want_recv_safe(l->rx.fd);
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +0200149}
150
151/* Disable receipt of incoming connections for listener <l>. The receiver must
Willy Tarreaua4380b22020-11-04 13:59:04 +0100152 * still be valid.
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +0200153 */
154static void udp_disable_listener(struct listener *l)
155{
Willy Tarreaua4380b22020-11-04 13:59:04 +0100156 fd_stop_recv(l->rx.fd);
Willy Tarreau5ddf1ce2020-09-25 19:27:39 +0200157}
158
Willy Tarreaucb66ea62020-09-25 17:12:32 +0200159/* Suspend a receiver. Returns < 0 in case of failure, 0 if the receiver
160 * was totally stopped, or > 0 if correctly suspended.
Willy Tarreaue122dc52020-10-07 19:55:15 +0200161 * The principle is a bit ugly but works well, at least on Linux: in order to
162 * suspend the receiver, we want it to stop receiving traffic, which means that
163 * the socket must be unhashed from the kernel's socket table. The simple way
164 * to do this is to connect to any address that is reachable and will not be
165 * used by regular traffic, and a great one is reconnecting to self.
Emeric Brun3835c0d2020-07-07 09:46:09 +0200166 */
Willy Tarreaucb66ea62020-09-25 17:12:32 +0200167static int udp_suspend_receiver(struct receiver *rx)
Emeric Brun3835c0d2020-07-07 09:46:09 +0200168{
Willy Tarreaue122dc52020-10-07 19:55:15 +0200169 struct sockaddr_storage ss;
170 socklen_t len = sizeof(ss);
171
172 if (rx->fd < 0)
173 return 0;
174
Willy Tarreau59b5da42020-11-04 14:14:55 +0100175 /* we never do that with a shared FD otherwise we'd break it in the
176 * parent process and any possible subsequent worker inheriting it.
177 */
178 if (rx->flags & RX_F_INHERITED)
179 return -1;
180
Willy Tarreaue122dc52020-10-07 19:55:15 +0200181 if (getsockname(rx->fd, (struct sockaddr *)&ss, &len) < 0)
182 return -1;
183
184 if (connect(rx->fd, (struct sockaddr *)&ss, len) < 0)
185 return -1;
186
187 /* not necessary but may make debugging clearer */
188 fd_stop_recv(rx->fd);
189 return 1;
190}
191
192/* Resume a receiver. Returns < 0 in case of failure, 0 if the receiver
193 * was totally stopped, or > 0 if correctly suspended.
194 * The principle is to reverse the change above, we'll break the connection by
195 * connecting to AF_UNSPEC. The association breaks and the socket starts to
196 * receive from everywhere again.
197 */
198static int udp_resume_receiver(struct receiver *rx)
199{
Willy Tarreau2f6f3622020-10-14 10:50:41 +0200200 const struct sockaddr sa = { .sa_family = AF_UNSPEC };
Willy Tarreaue122dc52020-10-07 19:55:15 +0200201
202 if (rx->fd < 0)
203 return 0;
204
Willy Tarreau2f6f3622020-10-14 10:50:41 +0200205 if (connect(rx->fd, &sa, sizeof(sa)) < 0)
Willy Tarreaue122dc52020-10-07 19:55:15 +0200206 return -1;
207
208 fd_want_recv(rx->fd);
209 return 1;
Emeric Brun3835c0d2020-07-07 09:46:09 +0200210}
211
212/*
213 * Local variables:
214 * c-indent-level: 8
215 * c-basic-offset: 8
216 * End:
217 */