summaryrefslogtreecommitdiffstats
path: root/src/proto_udp.c
blob: 7308e988b9fc9ff9bdf58c08cf60ec90e7624947 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
/*
 * UDP protocol layer on top of AF_INET/AF_INET6
 *
 * Copyright 2019 HAProxy Technologies, Frederic Lecaille <flecaille@haproxy.com>
 *
 * Partial merge by Emeric Brun <ebrun@haproxy.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 */

#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/types.h>

#include <netinet/udp.h>
#include <netinet/in.h>

#include <haproxy/fd.h>
#include <haproxy/listener.h>
#include <haproxy/log.h>
#include <haproxy/namespace.h>
#include <haproxy/port_range.h>
#include <haproxy/protocol.h>
#include <haproxy/proto_udp.h>
#include <haproxy/proxy.h>
#include <haproxy/server.h>
#include <haproxy/sock.h>
#include <haproxy/sock_inet.h>
#include <haproxy/task.h>
#include <haproxy/tools.h>

static int udp_bind_listener(struct listener *listener, char *errmsg, int errlen);
static void udp_enable_listener(struct listener *listener);
static void udp_disable_listener(struct listener *listener);

/* Note: must not be declared <const> as its list will be overwritten */
struct protocol proto_udp4 = {
	.name           = "udp4",

	/* connection layer */
	.xprt_type      = PROTO_TYPE_DGRAM,
	.listen         = udp_bind_listener,
	.enable         = udp_enable_listener,
	.disable        = udp_disable_listener,
	.add            = default_add_listener,
	.unbind         = default_unbind_listener,
	.suspend        = default_suspend_listener,
	.resume         = default_resume_listener,

	/* binding layer */
	.rx_suspend     = udp_suspend_receiver,
	.rx_resume      = udp_resume_receiver,

	/* address family */
	.fam            = &proto_fam_inet4,

	/* socket layer */
	.proto_type     = PROTO_TYPE_DGRAM,
	.sock_type      = SOCK_DGRAM,
	.sock_prot      = IPPROTO_UDP,
	.rx_enable      = sock_enable,
	.rx_disable     = sock_disable,
	.rx_unbind      = sock_unbind,
	.receivers      = LIST_HEAD_INIT(proto_udp4.receivers),
	.nb_receivers   = 0,
#ifdef SO_REUSEPORT
	.flags          = PROTO_F_REUSEPORT_SUPPORTED,
#endif
};

INITCALL1(STG_REGISTER, protocol_register, &proto_udp4);

/* Note: must not be declared <const> as its list will be overwritten */
struct protocol proto_udp6 = {
	.name           = "udp6",

	/* connection layer */
	.xprt_type      = PROTO_TYPE_DGRAM,
	.listen         = udp_bind_listener,
	.enable         = udp_enable_listener,
	.disable        = udp_disable_listener,
	.add            = default_add_listener,
	.unbind         = default_unbind_listener,
	.suspend        = default_suspend_listener,
	.resume         = default_resume_listener,

	/* binding layer */
	.rx_suspend     = udp_suspend_receiver,
	.rx_resume      = udp_resume_receiver,

	/* address family */
	.fam            = &proto_fam_inet6,

	/* socket layer */
	.proto_type     = PROTO_TYPE_DGRAM,
	.sock_type      = SOCK_DGRAM,
	.sock_prot      = IPPROTO_UDP,
	.rx_enable      = sock_enable,
	.rx_disable     = sock_disable,
	.rx_unbind      = sock_unbind,
	.receivers      = LIST_HEAD_INIT(proto_udp6.receivers),
	.nb_receivers   = 0,
#ifdef SO_REUSEPORT
	.flags          = PROTO_F_REUSEPORT_SUPPORTED,
#endif
};

INITCALL1(STG_REGISTER, protocol_register, &proto_udp6);

/* This function tries to bind a UDPv4/v6 listener. It may return a warning or
 * an error message in <errmsg> if the message is at most <errlen> bytes long
 * (including '\0'). Note that <errmsg> may be NULL if <errlen> is also zero.
 * The return value is composed from ERR_ABORT, ERR_WARN,
 * ERR_ALERT, ERR_RETRYABLE and ERR_FATAL. ERR_NONE indicates that everything
 * was alright and that no message was returned. ERR_RETRYABLE means that an
 * error occurred but that it may vanish after a retry (eg: port in use), and
 * ERR_FATAL indicates a non-fixable error. ERR_WARN and ERR_ALERT do not alter
 * the meaning of the error, but just indicate that a message is present which
 * should be displayed with the respective level. Last, ERR_ABORT indicates
 * that it's pointless to try to start other listeners. No error message is
 * returned if errlen is NULL.
 */
int udp_bind_listener(struct listener *listener, char *errmsg, int errlen)
{
	int err = ERR_NONE;
	char *msg = NULL;

	/* ensure we never return garbage */
	if (errlen)
		*errmsg = 0;

	if (listener->state != LI_ASSIGNED)
		return ERR_NONE; /* already bound */

	if (!(listener->rx.flags & RX_F_BOUND)) {
		msg = "receiving socket not bound";
		goto udp_return;
	}

	/* we may want to adjust the output buffer (tune.sndbuf.backend) */
	if (global.tune.frontend_rcvbuf)
		setsockopt(listener->rx.fd, SOL_SOCKET, SO_RCVBUF, &global.tune.frontend_rcvbuf, sizeof(global.tune.frontend_rcvbuf));

	if (global.tune.frontend_sndbuf)
		setsockopt(listener->rx.fd, SOL_SOCKET, SO_SNDBUF, &global.tune.frontend_sndbuf, sizeof(global.tune.frontend_sndbuf));

	if (listener->rx.flags & RX_F_PASS_PKTINFO) {
		/* set IP_PKTINFO to retrieve destination address on recv */
		switch (listener->rx.addr.ss_family) {
		case AF_INET:
#if defined(IP_PKTINFO)
			setsockopt(listener->rx.fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
#elif defined(IP_RECVDSTADDR)
			setsockopt(listener->rx.fd, IPPROTO_IP, IP_RECVDSTADDR, &one, sizeof(one));
#endif /* IP_PKTINFO || IP_RECVDSTADDR */
			break;
		case AF_INET6:
#ifdef IPV6_RECVPKTINFO
			setsockopt(listener->rx.fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
#endif
			break;
		default:
			break;
		}
	}

	listener_set_state(listener, LI_LISTEN);

 udp_return:
	if (msg && errlen) {
		char pn[INET6_ADDRSTRLEN];

		addr_to_str(&listener->rx.addr, pn, sizeof(pn));
		snprintf(errmsg, errlen, "%s for [%s:%d]", msg, pn, get_host_port(&listener->rx.addr));
	}
	return err;
}

/* Enable receipt of incoming connections for listener <l>. The receiver must
 * still be valid.
 */
static void udp_enable_listener(struct listener *l)
{
	fd_want_recv_safe(l->rx.fd);
}

/* Disable receipt of incoming connections for listener <l>. The receiver must
 * still be valid.
 */
static void udp_disable_listener(struct listener *l)
{
	fd_stop_recv(l->rx.fd);
}

/* Suspend a receiver. Returns < 0 in case of failure, 0 if the receiver
 * was totally stopped, or > 0 if correctly suspended.
 * The principle is a bit ugly but works well, at least on Linux: in order to
 * suspend the receiver, we want it to stop receiving traffic, which means that
 * the socket must be unhashed from the kernel's socket table. The simple way
 * to do this is to connect to any address that is reachable and will not be
 * used by regular traffic, and a great one is reconnecting to self. Note that
 * inherited FDs are neither suspended nor resumed, we only enable/disable
 * polling on them.
 */
int udp_suspend_receiver(struct receiver *rx)
{
	struct sockaddr_storage ss;
	socklen_t len = sizeof(ss);

	if (rx->fd < 0)
		return 0;

	/* we never do that with a shared FD otherwise we'd break it in the
	 * parent process and any possible subsequent worker inheriting it.
	 */
	if (rx->flags & RX_F_INHERITED)
		goto done;

	if (getsockname(rx->fd, (struct sockaddr *)&ss, &len) < 0)
		return -1;

	if (connect(rx->fd, (struct sockaddr *)&ss, len) < 0)
		return -1;
 done:
	/* not necessary but may make debugging clearer */
	fd_stop_recv(rx->fd);
	return 1;
}

/* Resume a receiver. Returns < 0 in case of failure, 0 if the receiver
 * was totally stopped, or > 0 if correctly suspended.
 * The principle is to reverse the change above, we'll break the connection by
 * connecting to AF_UNSPEC. The association breaks and the socket starts to
 * receive from everywhere again. Note that inherited FDs are neither suspended
 * nor resumed, we only enable/disable polling on them.
 */
int udp_resume_receiver(struct receiver *rx)
{
	const struct sockaddr sa = { .sa_family = AF_UNSPEC };

	if (rx->fd < 0)
		return 0;

	if (!(rx->flags & RX_F_INHERITED) && connect(rx->fd, &sa, sizeof(sa)) < 0)
		return -1;

	fd_want_recv(rx->fd);
	return 1;
}

/*
 * Local variables:
 *  c-indent-level: 8
 *  c-basic-offset: 8
 * End:
 */