Fix: Connect timeout arithmetic in inet/inet6 (v4)
[lttng-tools.git] / src / common / sessiond-comm / inet.c
1 /*
2 * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License, version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, write to the Free Software Foundation, Inc., 51
15 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
16 */
17
18 #define _LGPL_SOURCE
19 #include <assert.h>
20 #include <limits.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <sys/stat.h>
25 #include <sys/types.h>
26 #include <unistd.h>
27 #include <errno.h>
28 #include <fcntl.h>
29 #include <common/compat/time.h>
30 #include <poll.h>
31
32 #include <common/common.h>
33 #include <common/time.h>
34
35 #include "inet.h"
36
37 #define RECONNECT_DELAY 200 /* ms */
38
39 /*
40 * INET protocol operations.
41 */
42 static const struct lttcomm_proto_ops inet_ops = {
43 .bind = lttcomm_bind_inet_sock,
44 .close = lttcomm_close_inet_sock,
45 .connect = lttcomm_connect_inet_sock,
46 .accept = lttcomm_accept_inet_sock,
47 .listen = lttcomm_listen_inet_sock,
48 .recvmsg = lttcomm_recvmsg_inet_sock,
49 .sendmsg = lttcomm_sendmsg_inet_sock,
50 };
51
52 unsigned long lttcomm_inet_tcp_timeout;
53
54 /*
55 * Creates an PF_INET socket.
56 */
57 LTTNG_HIDDEN
58 int lttcomm_create_inet_sock(struct lttcomm_sock *sock, int type, int proto)
59 {
60 int val = 1, ret;
61 unsigned long timeout;
62
63 /* Create server socket */
64 if ((sock->fd = socket(PF_INET, type, proto)) < 0) {
65 PERROR("socket inet");
66 goto error;
67 }
68
69 sock->ops = &inet_ops;
70
71 /*
72 * Set socket option to reuse the address.
73 */
74 ret = setsockopt(sock->fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(int));
75 if (ret < 0) {
76 PERROR("setsockopt inet");
77 goto error;
78 }
79 timeout = lttcomm_get_network_timeout();
80 if (timeout) {
81 ret = lttcomm_setsockopt_rcv_timeout(sock->fd, timeout);
82 if (ret) {
83 goto error;
84 }
85 ret = lttcomm_setsockopt_snd_timeout(sock->fd, timeout);
86 if (ret) {
87 goto error;
88 }
89 }
90
91 return 0;
92
93 error:
94 return -1;
95 }
96
97 /*
98 * Bind socket and return.
99 */
100 LTTNG_HIDDEN
101 int lttcomm_bind_inet_sock(struct lttcomm_sock *sock)
102 {
103 return bind(sock->fd,
104 (const struct sockaddr *) &sock->sockaddr.addr.sin,
105 sizeof(sock->sockaddr.addr.sin));
106 }
107
108 static
109 int connect_no_timeout(struct lttcomm_sock *sock)
110 {
111 return connect(sock->fd, (struct sockaddr *) &sock->sockaddr.addr.sin,
112 sizeof(sock->sockaddr.addr.sin));
113 }
114
115 static
116 int connect_with_timeout(struct lttcomm_sock *sock)
117 {
118 unsigned long timeout = lttcomm_get_network_timeout();
119 int ret, flags, connect_ret;
120 struct timespec orig_time, cur_time;
121 unsigned long diff_ms;
122
123 ret = fcntl(sock->fd, F_GETFL, 0);
124 if (ret == -1) {
125 PERROR("fcntl");
126 return -1;
127 }
128 flags = ret;
129
130 /* Set socket to nonblock */
131 ret = fcntl(sock->fd, F_SETFL, flags | O_NONBLOCK);
132 if (ret == -1) {
133 PERROR("fcntl");
134 return -1;
135 }
136
137 ret = lttng_clock_gettime(CLOCK_MONOTONIC, &orig_time);
138 if (ret == -1) {
139 PERROR("clock_gettime");
140 return -1;
141 }
142
143 connect_ret = connect(sock->fd,
144 (struct sockaddr *) &sock->sockaddr.addr.sin,
145 sizeof(sock->sockaddr.addr.sin));
146 if (connect_ret == -1 && errno != EAGAIN
147 && errno != EWOULDBLOCK
148 && errno != EINPROGRESS) {
149 goto error;
150 } else if (!connect_ret) {
151 /* Connect succeeded */
152 goto success;
153 }
154
155 DBG("Asynchronous connect for sock %d, performing polling with"
156 " timeout: %lums", sock->fd, timeout);
157 /*
158 * Perform poll loop following EINPROGRESS recommendation from
159 * connect(2) man page.
160 */
161 do {
162 struct pollfd fds;
163
164 fds.fd = sock->fd;
165 fds.events = POLLOUT;
166 fds.revents = 0;
167 ret = poll(&fds, 1, RECONNECT_DELAY);
168 if (ret < 0) {
169 goto error;
170 } else if (ret > 0) {
171 int optval;
172 socklen_t optval_len = sizeof(optval);
173
174 if (!(fds.revents & POLLOUT)) {
175 /* Either hup or error */
176 errno = EPIPE;
177 goto error;
178 }
179 /* got something */
180 ret = getsockopt(sock->fd, SOL_SOCKET,
181 SO_ERROR, &optval, &optval_len);
182 if (ret) {
183 PERROR("getsockopt");
184 goto error;
185 }
186 if (!optval) {
187 connect_ret = 0;
188 goto success;
189 } else {
190 /* Get actual connect() errno from opt_val */
191 errno = optval;
192 goto error;
193 }
194 }
195 /* ret == 0: timeout */
196 ret = lttng_clock_gettime(CLOCK_MONOTONIC, &cur_time);
197 if (ret == -1) {
198 PERROR("clock_gettime");
199 connect_ret = ret;
200 goto error;
201 }
202 if (timespec_to_ms(timespec_abs_diff(cur_time, orig_time), &diff_ms) < 0) {
203 ERR("timespec_to_ms input overflows milliseconds output");
204 connect_ret = -1;
205 goto error;
206 }
207 } while (diff_ms < timeout);
208
209 /* Timeout */
210 errno = ETIMEDOUT;
211 connect_ret = -1;
212
213 success:
214 /* Restore initial flags */
215 ret = fcntl(sock->fd, F_SETFL, flags);
216 if (ret == -1) {
217 PERROR("fcntl");
218 /* Continue anyway */
219 }
220 error:
221 return connect_ret;
222 }
223
224 /*
225 * Connect PF_INET socket.
226 */
227 LTTNG_HIDDEN
228 int lttcomm_connect_inet_sock(struct lttcomm_sock *sock)
229 {
230 int ret, closeret;
231
232 if (lttcomm_get_network_timeout()) {
233 ret = connect_with_timeout(sock);
234 } else {
235 ret = connect_no_timeout(sock);
236 }
237 if (ret < 0) {
238 PERROR("connect");
239 goto error_connect;
240 }
241
242 return ret;
243
244 error_connect:
245 closeret = close(sock->fd);
246 if (closeret) {
247 PERROR("close inet");
248 }
249
250 return ret;
251 }
252
253 /*
254 * Do an accept(2) on the sock and return the new lttcomm socket. The socket
255 * MUST be bind(2) before.
256 */
257 LTTNG_HIDDEN
258 struct lttcomm_sock *lttcomm_accept_inet_sock(struct lttcomm_sock *sock)
259 {
260 int new_fd;
261 socklen_t len;
262 struct lttcomm_sock *new_sock;
263 unsigned long timeout;
264
265 if (sock->proto == LTTCOMM_SOCK_UDP) {
266 /*
267 * accept(2) does not exist for UDP so simply return the passed socket.
268 */
269 new_sock = sock;
270 goto end;
271 }
272
273 new_sock = lttcomm_alloc_sock(sock->proto);
274 if (new_sock == NULL) {
275 goto error;
276 }
277
278 len = sizeof(new_sock->sockaddr.addr.sin);
279
280 /* Blocking call */
281 new_fd = accept(sock->fd, (struct sockaddr *) &new_sock->sockaddr.addr.sin,
282 &len);
283 if (new_fd < 0) {
284 PERROR("accept inet");
285 goto error;
286 }
287 timeout = lttcomm_get_network_timeout();
288 if (timeout) {
289 int ret;
290
291 ret = lttcomm_setsockopt_rcv_timeout(new_fd, timeout);
292 if (ret) {
293 goto error_close;
294 }
295 ret = lttcomm_setsockopt_snd_timeout(new_fd, timeout);
296 if (ret) {
297 goto error_close;
298 }
299 }
300
301 new_sock->fd = new_fd;
302 new_sock->ops = &inet_ops;
303
304 end:
305 return new_sock;
306
307 error_close:
308 if (close(new_fd) < 0) {
309 PERROR("accept inet close fd");
310 }
311
312 error:
313 free(new_sock);
314 return NULL;
315 }
316
317 /*
318 * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
319 */
320 LTTNG_HIDDEN
321 int lttcomm_listen_inet_sock(struct lttcomm_sock *sock, int backlog)
322 {
323 int ret;
324
325 if (sock->proto == LTTCOMM_SOCK_UDP) {
326 /* listen(2) does not exist for UDP so simply return success. */
327 ret = 0;
328 goto end;
329 }
330
331 /* Default listen backlog */
332 if (backlog <= 0) {
333 backlog = LTTNG_SESSIOND_COMM_MAX_LISTEN;
334 }
335
336 ret = listen(sock->fd, backlog);
337 if (ret < 0) {
338 PERROR("listen inet");
339 }
340
341 end:
342 return ret;
343 }
344
345 /*
346 * Receive data of size len in put that data into the buf param. Using recvmsg
347 * API.
348 *
349 * Return the size of received data.
350 */
351 LTTNG_HIDDEN
352 ssize_t lttcomm_recvmsg_inet_sock(struct lttcomm_sock *sock, void *buf,
353 size_t len, int flags)
354 {
355 struct msghdr msg;
356 struct iovec iov[1];
357 ssize_t ret = -1;
358 size_t len_last;
359
360 memset(&msg, 0, sizeof(msg));
361
362 iov[0].iov_base = buf;
363 iov[0].iov_len = len;
364 msg.msg_iov = iov;
365 msg.msg_iovlen = 1;
366
367 msg.msg_name = (struct sockaddr *) &sock->sockaddr.addr.sin;
368 msg.msg_namelen = sizeof(sock->sockaddr.addr.sin);
369
370 do {
371 len_last = iov[0].iov_len;
372 ret = recvmsg(sock->fd, &msg, flags);
373 if (ret > 0) {
374 if (flags & MSG_DONTWAIT) {
375 goto end;
376 }
377 iov[0].iov_base += ret;
378 iov[0].iov_len -= ret;
379 assert(ret <= len_last);
380 }
381 } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
382
383 if (ret < 0) {
384 PERROR("recvmsg inet");
385 } else if (ret > 0) {
386 ret = len;
387 }
388 /* Else ret = 0 meaning an orderly shutdown. */
389 end:
390 return ret;
391 }
392
393 /*
394 * Send buf data of size len. Using sendmsg API.
395 *
396 * Return the size of sent data.
397 */
398 LTTNG_HIDDEN
399 ssize_t lttcomm_sendmsg_inet_sock(struct lttcomm_sock *sock, const void *buf,
400 size_t len, int flags)
401 {
402 struct msghdr msg;
403 struct iovec iov[1];
404 ssize_t ret = -1;
405
406 memset(&msg, 0, sizeof(msg));
407
408 iov[0].iov_base = (void *) buf;
409 iov[0].iov_len = len;
410 msg.msg_iov = iov;
411 msg.msg_iovlen = 1;
412
413 switch (sock->proto) {
414 case LTTCOMM_SOCK_UDP:
415 msg.msg_name = (struct sockaddr *) &sock->sockaddr.addr.sin;
416 msg.msg_namelen = sizeof(sock->sockaddr.addr.sin);
417 break;
418 default:
419 break;
420 }
421
422 do {
423 ret = sendmsg(sock->fd, &msg, flags);
424 } while (ret < 0 && errno == EINTR);
425 if (ret < 0) {
426 /*
427 * Only warn about EPIPE when quiet mode is deactivated.
428 * We consider EPIPE as expected.
429 */
430 if (errno != EPIPE || !lttng_opt_quiet) {
431 PERROR("sendmsg inet");
432 }
433 }
434
435 return ret;
436 }
437
438 /*
439 * Shutdown cleanly and close.
440 */
441 LTTNG_HIDDEN
442 int lttcomm_close_inet_sock(struct lttcomm_sock *sock)
443 {
444 int ret;
445
446 /* Don't try to close an invalid marked socket */
447 if (sock->fd == -1) {
448 return 0;
449 }
450
451 ret = close(sock->fd);
452 if (ret) {
453 PERROR("close inet");
454 }
455
456 /* Mark socket */
457 sock->fd = -1;
458
459 return ret;
460 }
461
462 /*
463 * Return value read from /proc or else 0 if value is not found.
464 */
465 static unsigned long read_proc_value(const char *path)
466 {
467 int ret, fd;
468 ssize_t size_ret;
469 long r_val;
470 unsigned long val = 0;
471 char buf[64];
472
473 fd = open(path, O_RDONLY);
474 if (fd < 0) {
475 goto error;
476 }
477
478 size_ret = lttng_read(fd, buf, sizeof(buf));
479 /*
480 * Allow reading a file smaller than buf, but keep space for
481 * final \0.
482 */
483 if (size_ret < 0 || size_ret >= sizeof(buf)) {
484 PERROR("read proc failed");
485 goto error_close;
486 }
487 buf[size_ret] = '\0';
488
489 errno = 0;
490 r_val = strtol(buf, NULL, 10);
491 if (errno != 0 || r_val < -1L) {
492 val = 0;
493 goto error_close;
494 } else {
495 if (r_val > 0) {
496 val = r_val;
497 }
498 }
499
500 error_close:
501 ret = close(fd);
502 if (ret) {
503 PERROR("close /proc value");
504 }
505 error:
506 return val;
507 }
508
509 LTTNG_HIDDEN
510 void lttcomm_inet_init(void)
511 {
512 unsigned long syn_retries, fin_timeout, syn_timeout, env;
513
514 env = lttcomm_get_network_timeout();
515 if (env) {
516 lttcomm_inet_tcp_timeout = env;
517 goto end;
518 }
519
520 /* Assign default value and see if we can change it. */
521 lttcomm_inet_tcp_timeout = DEFAULT_INET_TCP_TIMEOUT;
522
523 syn_retries = read_proc_value(LTTCOMM_INET_PROC_SYN_RETRIES_PATH);
524 fin_timeout = read_proc_value(LTTCOMM_INET_PROC_FIN_TIMEOUT_PATH);
525
526 syn_timeout = syn_retries * LTTCOMM_INET_SYN_TIMEOUT_FACTOR;
527
528 /*
529 * Get the maximum between the two possible timeout value and use that to
530 * get the maximum with the default timeout.
531 */
532 lttcomm_inet_tcp_timeout = max_t(unsigned long,
533 max_t(unsigned long, syn_timeout, fin_timeout),
534 lttcomm_inet_tcp_timeout);
535
536 end:
537 DBG("TCP inet operation timeout set to %lu sec", lttcomm_inet_tcp_timeout);
538 }
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