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
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
|
/*
* (C) 2009 by Pablo Neira Ayuso <pablo@netfilter.org>
*
* 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.
*
* TCP support has been sponsored by 6WIND <www.6wind.com>.
*/
#include "tcp.h"
#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include "conntrackd.h"
#include "fds.h"
struct tcp_sock *tcp_server_create(struct tcp_conf *c)
{
int yes = 1, ret;
struct tcp_sock *m;
socklen_t socklen = sizeof(int);
m = calloc(sizeof(struct tcp_sock), 1);
if (m == NULL)
return NULL;
m->conf = c;
switch(c->ipproto) {
case AF_INET:
m->addr.ipv4.sin_family = AF_INET;
m->addr.ipv4.sin_port = htons(c->port);
m->addr.ipv4.sin_addr = c->server.ipv4.inet_addr;
m->sockaddr_len = sizeof(struct sockaddr_in);
break;
case AF_INET6:
m->addr.ipv6.sin6_family = AF_INET6;
m->addr.ipv6.sin6_port = htons(c->port);
m->addr.ipv6.sin6_addr = c->server.ipv6.inet_addr6;
m->addr.ipv6.sin6_scope_id = c->server.ipv6.scope_id;
m->sockaddr_len = sizeof(struct sockaddr_in6);
break;
}
m->fd = socket(c->ipproto, SOCK_STREAM, 0);
if (m->fd == -1) {
free(m);
return NULL;
}
if (setsockopt(m->fd, SOL_SOCKET, SO_REUSEADDR, &yes,
sizeof(int)) == -1) {
close(m->fd);
free(m);
return NULL;
}
if (setsockopt(m->fd, SOL_SOCKET, SO_KEEPALIVE, &yes,
sizeof(int)) == -1) {
close(m->fd);
free(m);
return NULL;
}
#ifndef SO_RCVBUFFORCE
#define SO_RCVBUFFORCE 33
#endif
if (c->rcvbuf &&
setsockopt(m->fd, SOL_SOCKET, SO_RCVBUFFORCE, &c->rcvbuf,
sizeof(int)) == -1) {
/* not supported in linux kernel < 2.6.14 */
if (errno != ENOPROTOOPT) {
close(m->fd);
free(m);
return NULL;
}
}
getsockopt(m->fd, SOL_SOCKET, SO_RCVBUF, &c->rcvbuf, &socklen);
if (bind(m->fd, (struct sockaddr *) &m->addr, m->sockaddr_len) == -1) {
close(m->fd);
free(m);
return NULL;
}
if (listen(m->fd, 1) == -1) {
close(m->fd);
free(m);
return NULL;
}
if (fcntl(m->fd, F_SETFL, O_NONBLOCK) == -1) {
close(m->fd);
free(m);
return NULL;
}
/* now we accept new connections ... */
ret = accept(m->fd, NULL, NULL);
if (ret == -1) {
if (errno != EAGAIN) {
/* unexpected error, give up. */
close(m->fd);
free(m);
m = NULL;
} else {
/* still in progress ... we'll do it in tcp_recv() */
m->state = TCP_SERVER_ACCEPTING;
}
} else {
/* very unlikely at this stage. */
if (fcntl(ret, F_SETFL, O_NONBLOCK) == -1) {
/* unexpected error, give up. */
close(m->fd);
free(m);
return NULL;
}
m->client_fd = ret;
m->state = TCP_SERVER_CONNECTED;
register_fd(m->client_fd, STATE(fds));
}
return m;
}
void tcp_server_destroy(struct tcp_sock *m)
{
close(m->fd);
free(m);
}
static int
tcp_client_init(struct tcp_sock *m, struct tcp_conf *c)
{
int ret = 0;
socklen_t socklen = sizeof(int);
m->fd = socket(c->ipproto, SOCK_STREAM, 0);
if (m->fd == -1)
return -1;
if (setsockopt(m->fd, SOL_SOCKET, SO_NO_CHECK, &c->checksum,
sizeof(int)) == -1) {
close(m->fd);
return -1;
}
#ifndef SO_SNDBUFFORCE
#define SO_SNDBUFFORCE 32
#endif
if (c->sndbuf &&
setsockopt(m->fd, SOL_SOCKET, SO_SNDBUFFORCE, &c->sndbuf,
sizeof(int)) == -1) {
/* not supported in linux kernel < 2.6.14 */
if (errno != ENOPROTOOPT) {
close(m->fd);
return -1;
}
}
getsockopt(m->fd, SOL_SOCKET, SO_SNDBUF, &c->sndbuf, &socklen);
switch(c->ipproto) {
case AF_INET:
m->addr.ipv4.sin_family = AF_INET;
m->addr.ipv4.sin_port = htons(c->port);
m->addr.ipv4.sin_addr = c->client.inet_addr;
m->sockaddr_len = sizeof(struct sockaddr_in);
break;
case AF_INET6:
m->addr.ipv6.sin6_family = AF_INET6;
m->addr.ipv6.sin6_port = htons(c->port);
memcpy(&m->addr.ipv6.sin6_addr, &c->client.inet_addr6,
sizeof(struct in6_addr));
m->sockaddr_len = sizeof(struct sockaddr_in6);
break;
default:
ret = -1;
break;
}
if (ret == -1) {
close(m->fd);
return -1;
}
if (fcntl(m->fd, F_SETFL, O_NONBLOCK) == -1) {
close(m->fd);
return -1;
}
ret = connect(m->fd, (struct sockaddr *)&m->addr, m->sockaddr_len);
if (ret == -1) {
if (errno == EINPROGRESS) {
/* connection in progress ... */
m->state = TCP_CLIENT_DISCONNECTED;
} else if (errno == ECONNREFUSED) {
/* connection refused. */
m->state = TCP_CLIENT_DISCONNECTED;
} else {
/* unexpected error, give up. */
close(m->fd);
return -1;
}
} else {
/* very unlikely at this stage. */
m->state = TCP_CLIENT_CONNECTED;
}
return 0;
}
/* We use this to rate-limit the amount of connect() calls per second. */
static struct alarm_block tcp_connect_alarm;
static void tcp_connect_alarm_cb(struct alarm_block *a, void *data) {}
struct tcp_sock *tcp_client_create(struct tcp_conf *c)
{
struct tcp_sock *m;
m = calloc(sizeof(struct tcp_sock), 1);
if (m == NULL)
return NULL;
m->conf = c;
if (tcp_client_init(m, c) == -1) {
free(m);
return NULL;
}
init_alarm(&tcp_connect_alarm, NULL, tcp_connect_alarm_cb);
return m;
}
void tcp_client_destroy(struct tcp_sock *m)
{
close(m->fd);
free(m);
}
int tcp_accept(struct tcp_sock *m)
{
int ret;
/* we got an attempt to connect but we already have a client? */
if (m->state != TCP_SERVER_ACCEPTING) {
/* clear the session and restart ... */
unregister_fd(m->client_fd, STATE(fds));
close(m->client_fd);
m->client_fd = -1;
m->state = TCP_SERVER_ACCEPTING;
}
/* the other peer wants to connect ... */
ret = accept(m->fd, NULL, NULL);
if (ret == -1) {
if (errno != EAGAIN) {
/* unexpected error. Give us another try. */
m->state = TCP_SERVER_ACCEPTING;
} else {
/* waiting for new connections. */
m->state = TCP_SERVER_ACCEPTING;
}
} else {
/* the peer finally got connected. */
if (fcntl(ret, F_SETFL, O_NONBLOCK) == -1) {
/* close the connection and give us another chance. */
close(ret);
return -1;
}
m->client_fd = ret;
m->state = TCP_SERVER_CONNECTED;
register_fd(m->client_fd, STATE(fds));
}
return m->client_fd;
}
#define TCP_CONNECT_TIMEOUT 1
ssize_t tcp_send(struct tcp_sock *m, const void *data, int size)
{
ssize_t ret = 0;
switch(m->state) {
case TCP_CLIENT_DISCONNECTED:
/* We rate-limit the amount of connect() calls. */
if (alarm_pending(&tcp_connect_alarm)) {
ret = -1;
break;
}
add_alarm(&tcp_connect_alarm, TCP_CONNECT_TIMEOUT, 0);
ret = connect(m->fd, (struct sockaddr *)&m->addr,
m->sockaddr_len);
if (ret == -1) {
if (errno == EINPROGRESS || errno == EALREADY) {
/* connection in progress or already trying. */
m->state = TCP_CLIENT_DISCONNECTED;
} else if (errno == ECONNREFUSED) {
/* connection refused. */
m->state = TCP_CLIENT_DISCONNECTED;
m->stats.error++;
} else {
/* unexpected error, give up. */
m->state = TCP_CLIENT_DISCONNECTED;
m->stats.error++;
}
break;
} else {
/* we got connected :) */
m->state = TCP_CLIENT_CONNECTED;
}
case TCP_CLIENT_CONNECTED:
ret = sendto(m->fd, data, size, 0,
(struct sockaddr *) &m->addr, m->sockaddr_len);
if (ret == -1) {
if (errno == EPIPE || errno == ECONNRESET) {
close(m->fd);
tcp_client_init(m, m->conf);
m->state = TCP_CLIENT_DISCONNECTED;
m->stats.error++;
} else {
m->stats.error++;
return -1;
}
}
}
if (ret >= 0) {
m->stats.bytes += ret;
m->stats.messages++;
}
return ret;
}
ssize_t tcp_recv(struct tcp_sock *m, void *data, int size)
{
ssize_t ret = 0;
socklen_t sin_size = sizeof(struct sockaddr_in);
/* we are not connected, skip. */
if (m->state != TCP_SERVER_CONNECTED)
return 0;
ret = recvfrom(m->client_fd, data, size, 0,
(struct sockaddr *)&m->addr, &sin_size);
if (ret == -1) {
/* the other peer has disconnected... */
if (errno == ENOTCONN) {
unregister_fd(m->client_fd, STATE(fds));
close(m->client_fd);
m->client_fd = -1;
m->state = TCP_SERVER_ACCEPTING;
tcp_accept(m);
} else if (errno != EAGAIN) {
m->stats.error++;
}
} else if (ret == 0) {
/* the other peer has closed the connection... */
unregister_fd(m->client_fd, STATE(fds));
close(m->client_fd);
m->client_fd = -1;
m->state = TCP_SERVER_ACCEPTING;
tcp_accept(m);
}
if (ret >= 0) {
m->stats.bytes += ret;
m->stats.messages++;
}
return ret;
}
int tcp_get_fd(struct tcp_sock *m)
{
return m->fd;
}
int tcp_isset(struct tcp_sock *m, fd_set *readfds)
{
return m->client_fd >= 0 ? FD_ISSET(m->client_fd, readfds) : 0;
}
int tcp_accept_isset(struct tcp_sock *m, fd_set *readfds)
{
return FD_ISSET(m->fd, readfds);
}
int
tcp_snprintf_stats(char *buf, size_t buflen, char *ifname,
struct tcp_sock *client, struct tcp_sock *server)
{
size_t size;
struct tcp_stats *s = &client->stats, *r = &server->stats;
size = snprintf(buf, buflen, "TCP traffic (active device=%s) "
"server=%s client=%s:\n"
"%20llu Bytes sent "
"%20llu Bytes recv\n"
"%20llu Pckts sent "
"%20llu Pckts recv\n"
"%20llu Error send "
"%20llu Error recv\n\n",
ifname,
server->state == TCP_SERVER_CONNECTED ?
"connected" : "disconnected",
client->state == TCP_CLIENT_CONNECTED ?
"connected" : "disconnected",
(unsigned long long)s->bytes,
(unsigned long long)r->bytes,
(unsigned long long)s->messages,
(unsigned long long)r->messages,
(unsigned long long)s->error,
(unsigned long long)r->error);
return size;
}
int
tcp_snprintf_stats2(char *buf, size_t buflen, const char *ifname,
const char *status, int active,
struct tcp_stats *s, struct tcp_stats *r)
{
size_t size;
size = snprintf(buf, buflen,
"TCP traffic device=%s status=%s role=%s:\n"
"%20llu Bytes sent "
"%20llu Bytes recv\n"
"%20llu Pckts sent "
"%20llu Pckts recv\n"
"%20llu Error send "
"%20llu Error recv\n\n",
ifname, status, active ? "ACTIVE" : "BACKUP",
(unsigned long long)s->bytes,
(unsigned long long)r->bytes,
(unsigned long long)s->messages,
(unsigned long long)r->messages,
(unsigned long long)s->error,
(unsigned long long)r->error);
return size;
}
|