summaryrefslogtreecommitdiffstats
path: root/src/socket.c
blob: c84d2d141b3b27bf362681599503a143386edf96 (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
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
/*
  Copyright (c) 2012-2015, Matthias Schiffer <mschiffer@universe-factory.net>
  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice,
       this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright notice,
       this list of conditions and the following disclaimer in the documentation
       and/or other materials provided with the distribution.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/**
   \file

   Socket handling
*/

#include "fastd.h"
#include "poll.h"


/**
   Creates a new socket bound to a specific address

   \return The new socket's file descriptor
*/
static int bind_socket(const fastd_bind_address_t *addr, bool warn) {
	int fd = -1;
	int af = AF_UNSPEC;

	if (addr->addr.sa.sa_family != AF_INET) {
		fd = socket(PF_INET6, SOCK_DGRAM|SOCK_NONBLOCK, IPPROTO_UDP);
		if (fd >= 0) {
			af = AF_INET6;

			int val = (addr->addr.sa.sa_family == AF_INET6);
			if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val))) {
				if (warn)
					pr_warn_errno("setsockopt");
				goto error;
			}
		}
	}
	if (fd < 0 && addr->addr.sa.sa_family != AF_INET6) {
		fd = socket(PF_INET, SOCK_DGRAM|SOCK_NONBLOCK, IPPROTO_UDP);
		if (fd < 0)
			exit_errno("unable to create socket");
		else
			af = AF_INET;
	}

	if (fd < 0)
		goto error;

#ifdef NO_HAVE_SOCK_NONBLOCK
	fastd_setnonblock(fd);
#endif

	int one = 1;

#ifdef USE_PKTINFO
	if (setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one))) {
		pr_error_errno("setsockopt: unable to set IP_PKTINFO");
		goto error;
	}
#endif

#ifdef USE_FREEBIND
	if (setsockopt(fd, IPPROTO_IP, IP_FREEBIND, &one, sizeof(one)))
		pr_warn_errno("setsockopt: unable to set IP_FREEBIND");
#endif

	if (af == AF_INET6) {
		if (setsockopt(fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one))) {
			pr_error_errno("setsockopt: unable to set IPV6_RECVPKTINFO");
			goto error;
		}
	}

#ifdef USE_BINDTODEVICE
	if (addr->bindtodev && !fastd_peer_address_is_v6_ll(&addr->addr)) {
		if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, addr->bindtodev, strlen(addr->bindtodev))) {
			if (warn)
				pr_warn_errno("setsockopt: unable to bind to device");
			goto error;
		}
	}
#endif

#ifdef USE_PMTU
	if (conf.pmtu.set) {
		int pmtu = conf.pmtu.state ? IP_PMTUDISC_DO : IP_PMTUDISC_DONT;
		if (setsockopt(fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu))) {
			pr_error_errno("setsockopt: unable to set PMTU discovery");
			goto error;
		}
	}
#endif

#ifdef USE_PACKET_MARK
	if (conf.packet_mark) {
		if (setsockopt(fd, SOL_SOCKET, SO_MARK, &conf.packet_mark, sizeof(conf.packet_mark))) {
			pr_error_errno("setsockopt: unable to set packet mark");
			goto error;
		}
	}
#endif

	fastd_peer_address_t bind_address = addr->addr;

	if (fastd_peer_address_is_v6_ll(&addr->addr) && addr->bindtodev) {
		char *end;
		bind_address.in6.sin6_scope_id = strtoul(addr->bindtodev, &end, 10);

		if (*end)
			bind_address.in6.sin6_scope_id = if_nametoindex(addr->bindtodev);

		if (!bind_address.in6.sin6_scope_id) {
			if (warn)
				pr_warn_errno("if_nametoindex");
			goto error;
		}
	}

	if (bind_address.sa.sa_family == AF_UNSPEC) {
		memset(&bind_address, 0, sizeof(bind_address));
		bind_address.sa.sa_family = af;

		if (af == AF_INET6)
			bind_address.in6.sin6_port = addr->addr.in.sin_port;
		else
			bind_address.in.sin_port = addr->addr.in.sin_port;
	}

	if (bind(fd, &bind_address.sa, bind_address.sa.sa_family == AF_INET6 ? sizeof(struct sockaddr_in6) : sizeof(struct sockaddr_in))) {
		if (warn)
			pr_warn_errno("bind");
		goto error;
	}

#ifdef __ANDROID__
	if (!fastd_android_protect_socket(fd)) {
		pr_error("error protecting socket");
		goto error;
	}
#endif

	return fd;

 error:
	if (fd >= 0) {
		if (close(fd))
			pr_error_errno("close");
	}

	if (warn) {
		if (addr->bindtodev)
			pr_warn(fastd_peer_address_is_v6_ll(&addr->addr) ? "unable to bind to %L" : "unable to bind to %B on `%s'", &addr->addr, addr->bindtodev);
		else
			pr_warn("unable to bind to %B", &addr->addr);
	}

	return -1;
}

/** Gets the address a socket is bound to and sets it in the socket structure */
static bool set_bound_address(fastd_socket_t *sock) {
	fastd_peer_address_t addr = {};
	socklen_t len = sizeof(addr);

	if (getsockname(sock->fd, &addr.sa, &len) < 0) {
		pr_error_errno("getsockname");
		return false;
	}

	if (len > sizeof(addr)) {
		pr_error("getsockname: got strange long address");
		return false;
	}

	sock->bound_addr = fastd_new0(fastd_peer_address_t);
	*sock->bound_addr = addr;

	return true;
}

/** Tries to initialize sockets for all configured bind addresses */
bool fastd_socket_handle_binds(void) {
	size_t i;

	for (i = 0; i < ctx.n_socks; i++) {
		if (ctx.socks[i].fd >= 0)
			continue;

		if (!ctx.socks[i].addr)
			continue;

		ctx.socks[i].fd = bind_socket(ctx.socks[i].addr, ctx.socks[i].fd < -1);

		if (ctx.socks[i].fd >= 0) {
			if (!set_bound_address(&ctx.socks[i])) {
				fastd_socket_close(&ctx.socks[i]);
				continue;
			}

			fastd_poll_set_fd_sock(i);

			fastd_peer_address_t bound_addr = *ctx.socks[i].bound_addr;
			if (!ctx.socks[i].addr->addr.sa.sa_family)
				bound_addr.sa.sa_family = AF_UNSPEC;

			if (ctx.socks[i].addr->bindtodev && !fastd_peer_address_is_v6_ll(&bound_addr))
				pr_info("successfully bound to %B on `%s'", &bound_addr, ctx.socks[i].addr->bindtodev);
			else
				pr_info("successfully bound to %B", &bound_addr);
		}
	}

	if ((ctx.sock_default_v4 && ctx.sock_default_v4->fd < 0) || (ctx.sock_default_v6 && ctx.sock_default_v6->fd < 0))
		return false;

	return true;
}

/** Opens a single socket bound to a random port for the given address family */
fastd_socket_t * fastd_socket_open(fastd_peer_t *peer, int af) {
	const fastd_bind_address_t any_address = { .addr.sa.sa_family = af };

	const fastd_bind_address_t *bind_address;

	if (af == AF_INET && conf.bind_addr_default_v4)
		bind_address = conf.bind_addr_default_v4;
	else if (af == AF_INET6 && conf.bind_addr_default_v6)
		bind_address = conf.bind_addr_default_v6;
	else
		bind_address = &any_address;

	int fd = bind_socket(bind_address, true);
	if (fd < 0)
		return NULL;

	fastd_socket_t *sock = fastd_new(fastd_socket_t);

	sock->fd = fd;
	sock->addr = NULL;
	sock->bound_addr = NULL;
	sock->peer = peer;

	if (!set_bound_address(sock)) {
		fastd_socket_close(sock);
		free(sock);
		return NULL;
	}

	return sock;
}

/** Closes a socket */
void fastd_socket_close(fastd_socket_t *sock) {
	if (sock->fd >= 0) {
		if(close(sock->fd))
			pr_error_errno("closing socket: close");

		sock->fd = -2;
	}

	if (sock->bound_addr) {
		free(sock->bound_addr);
		sock->bound_addr = NULL;
	}
}

/** Handles an error that occured on a socket */
void fastd_socket_error(fastd_socket_t *sock) {
	if (sock->addr->bindtodev)
		pr_warn("socket bind %I on `%s' lost", &sock->addr->addr, sock->addr->bindtodev);
	else
		pr_warn("socket bind %I lost", &sock->addr->addr);

	fastd_socket_close(sock);
}