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         int ret;
 104
 105         ret = bind(sock->fd, (const struct sockaddr *) &sock->sockaddr.addr.sin,
 106                         sizeof(sock->sockaddr.addr.sin));
 107         if (ret < 0) {
 108                 PERROR("bind inet");
 109         }
 110
 111         return ret;
 112 }
 113
 114 static
 115 int connect_no_timeout(struct lttcomm_sock *sock)
 116 {
 117         return connect(sock->fd, (struct sockaddr *) &sock->sockaddr.addr.sin,
 118                         sizeof(sock->sockaddr.addr.sin));
 119 }
 120
 121 /*
 122  * Return time_a - time_b  in milliseconds.
 123  */
 124 static
 125 unsigned long time_diff_ms(struct timespec *time_a,
 126                 struct timespec *time_b)
 127 {
 128         time_t sec_diff;
 129         long nsec_diff;
 130         unsigned long result_ms;
 131
 132         sec_diff = time_a->tv_sec - time_b->tv_sec;
 133         nsec_diff = time_a->tv_nsec - time_b->tv_nsec;
 134
 135         result_ms = sec_diff * MSEC_PER_SEC;
 136         result_ms += nsec_diff / NSEC_PER_MSEC;
 137         return result_ms;
 138 }
 139
 140 static
 141 int connect_with_timeout(struct lttcomm_sock *sock)
 142 {
 143         unsigned long timeout = lttcomm_get_network_timeout();
 144         int ret, flags, connect_ret;
 145         struct timespec orig_time, cur_time;
 146
 147         ret = fcntl(sock->fd, F_GETFL, 0);
 148         if (ret == -1) {
 149                 PERROR("fcntl");
 150                 return -1;
 151         }
 152         flags = ret;
 153
 154         /* Set socket to nonblock */
 155         ret = fcntl(sock->fd, F_SETFL, flags | O_NONBLOCK);
 156         if (ret == -1) {
 157                 PERROR("fcntl");
 158                 return -1;
 159         }
 160
 161         ret = lttng_clock_gettime(CLOCK_MONOTONIC, &orig_time);
 162         if (ret == -1) {
 163                 PERROR("clock_gettime");
 164                 return -1;
 165         }
 166
 167         connect_ret = connect(sock->fd,
 168                 (struct sockaddr *) &sock->sockaddr.addr.sin,
 169                 sizeof(sock->sockaddr.addr.sin));
 170         if (connect_ret == -1 && errno != EAGAIN
 171                         && errno != EWOULDBLOCK
 172                         && errno != EINPROGRESS) {
 173                 goto error;
 174         } else if (!connect_ret) {
 175                 /* Connect succeeded */
 176                 goto success;
 177         }
 178
 179         DBG("Asynchronous connect for sock %d, performing polling with"
 180                         " timeout: %lums", sock->fd, timeout);
 181         /*
 182          * Perform poll loop following EINPROGRESS recommendation from
 183          * connect(2) man page.
 184          */
 185         do {
 186                 struct pollfd fds;
 187
 188                 fds.fd = sock->fd;
 189                 fds.events = POLLOUT;
 190                 fds.revents = 0;
 191                 ret = poll(&fds, 1, RECONNECT_DELAY);
 192                 if (ret < 0) {
 193                         goto error;
 194                 } else if (ret > 0) {
 195                         int optval;
 196                         socklen_t optval_len = sizeof(optval);
 197
 198                         if (!(fds.revents & POLLOUT)) {
 199                                 /* Either hup or error */
 200                                 errno = EPIPE;
 201                                 goto error;
 202                         }
 203                         /* got something */
 204                         ret = getsockopt(sock->fd, SOL_SOCKET,
 205                                 SO_ERROR, &optval, &optval_len);
 206                         if (ret) {
 207                                 PERROR("getsockopt");
 208                                 goto error;
 209                         }
 210                         if (!optval) {
 211                                 connect_ret = 0;
 212                                 goto success;
 213                         } else {
 214                                 /* Get actual connect() errno from opt_val */
 215                                 errno = optval;
 216                                 goto error;
 217                         }
 218                 }
 219                 /* ret == 0: timeout */
 220                 ret = lttng_clock_gettime(CLOCK_MONOTONIC, &cur_time);
 221                 if (ret == -1) {
 222                         PERROR("clock_gettime");
 223                         connect_ret = ret;
 224                         goto error;
 225                 }
 226         } while (time_diff_ms(&cur_time, &orig_time) < timeout);
 227
 228         /* Timeout */
 229         errno = ETIMEDOUT;
 230         connect_ret = -1;
 231
 232 success:
 233         /* Restore initial flags */
 234         ret = fcntl(sock->fd, F_SETFL, flags);
 235         if (ret == -1) {
 236                 PERROR("fcntl");
 237                 /* Continue anyway */
 238         }
 239 error:
 240         return connect_ret;
 241 }
 242
 243 /*
 244  * Connect PF_INET socket.
 245  */
 246 LTTNG_HIDDEN
 247 int lttcomm_connect_inet_sock(struct lttcomm_sock *sock)
 248 {
 249         int ret, closeret;
 250
 251         if (lttcomm_get_network_timeout()) {
 252                 ret = connect_with_timeout(sock);
 253         } else {
 254                 ret = connect_no_timeout(sock);
 255         }
 256         if (ret < 0) {
 257                 PERROR("connect");
 258                 goto error_connect;
 259         }
 260
 261         return ret;
 262
 263 error_connect:
 264         closeret = close(sock->fd);
 265         if (closeret) {
 266                 PERROR("close inet");
 267         }
 268
 269         return ret;
 270 }
 271
 272 /*
 273  * Do an accept(2) on the sock and return the new lttcomm socket. The socket
 274  * MUST be bind(2) before.
 275  */
 276 LTTNG_HIDDEN
 277 struct lttcomm_sock *lttcomm_accept_inet_sock(struct lttcomm_sock *sock)
 278 {
 279         int new_fd;
 280         socklen_t len;
 281         struct lttcomm_sock *new_sock;
 282         unsigned long timeout;
 283
 284         if (sock->proto == LTTCOMM_SOCK_UDP) {
 285                 /*
 286                  * accept(2) does not exist for UDP so simply return the passed socket.
 287                  */
 288                 new_sock = sock;
 289                 goto end;
 290         }
 291
 292         new_sock = lttcomm_alloc_sock(sock->proto);
 293         if (new_sock == NULL) {
 294                 goto error;
 295         }
 296
 297         len = sizeof(new_sock->sockaddr.addr.sin);
 298
 299         /* Blocking call */
 300         new_fd = accept(sock->fd, (struct sockaddr *) &new_sock->sockaddr.addr.sin,
 301                         &len);
 302         if (new_fd < 0) {
 303                 PERROR("accept inet");
 304                 goto error;
 305         }
 306         timeout = lttcomm_get_network_timeout();
 307         if (timeout) {
 308                 int ret;
 309
 310                 ret = lttcomm_setsockopt_rcv_timeout(new_fd, timeout);
 311                 if (ret) {
 312                         goto error_close;
 313                 }
 314                 ret = lttcomm_setsockopt_snd_timeout(new_fd, timeout);
 315                 if (ret) {
 316                         goto error_close;
 317                 }
 318         }
 319
 320         new_sock->fd = new_fd;
 321         new_sock->ops = &inet_ops;
 322
 323 end:
 324         return new_sock;
 325
 326 error_close:
 327         if (close(new_fd) < 0) {
 328                 PERROR("accept inet close fd");
 329         }
 330
 331 error:
 332         free(new_sock);
 333         return NULL;
 334 }
 335
 336 /*
 337  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 338  */
 339 LTTNG_HIDDEN
 340 int lttcomm_listen_inet_sock(struct lttcomm_sock *sock, int backlog)
 341 {
 342         int ret;
 343
 344         if (sock->proto == LTTCOMM_SOCK_UDP) {
 345                 /* listen(2) does not exist for UDP so simply return success. */
 346                 ret = 0;
 347                 goto end;
 348         }
 349
 350         /* Default listen backlog */
 351         if (backlog <= 0) {
 352                 backlog = LTTNG_SESSIOND_COMM_MAX_LISTEN;
 353         }
 354
 355         ret = listen(sock->fd, backlog);
 356         if (ret < 0) {
 357                 PERROR("listen inet");
 358         }
 359
 360 end:
 361         return ret;
 362 }
 363
 364 /*
 365  * Receive data of size len in put that data into the buf param. Using recvmsg
 366  * API.
 367  *
 368  * Return the size of received data.
 369  */
 370 LTTNG_HIDDEN
 371 ssize_t lttcomm_recvmsg_inet_sock(struct lttcomm_sock *sock, void *buf,
 372                 size_t len, int flags)
 373 {
 374         struct msghdr msg;
 375         struct iovec iov[1];
 376         ssize_t ret = -1;
 377         size_t len_last;
 378
 379         memset(&msg, 0, sizeof(msg));
 380
 381         iov[0].iov_base = buf;
 382         iov[0].iov_len = len;
 383         msg.msg_iov = iov;
 384         msg.msg_iovlen = 1;
 385
 386         msg.msg_name = (struct sockaddr *) &sock->sockaddr.addr.sin;
 387         msg.msg_namelen = sizeof(sock->sockaddr.addr.sin);
 388
 389         do {
 390                 len_last = iov[0].iov_len;
 391                 ret = recvmsg(sock->fd, &msg, flags);
 392                 if (ret > 0) {
 393                         iov[0].iov_base += ret;
 394                         iov[0].iov_len -= ret;
 395                         assert(ret <= len_last);
 396                 }
 397         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 398         if (ret < 0) {
 399                 PERROR("recvmsg inet");
 400         } else if (ret > 0) {
 401                 ret = len;
 402         }
 403         /* Else ret = 0 meaning an orderly shutdown. */
 404
 405         return ret;
 406 }
 407
 408 /*
 409  * Send buf data of size len. Using sendmsg API.
 410  *
 411  * Return the size of sent data.
 412  */
 413 LTTNG_HIDDEN
 414 ssize_t lttcomm_sendmsg_inet_sock(struct lttcomm_sock *sock, const void *buf,
 415                 size_t len, int flags)
 416 {
 417         struct msghdr msg;
 418         struct iovec iov[1];
 419         ssize_t ret = -1;
 420
 421         memset(&msg, 0, sizeof(msg));
 422
 423         iov[0].iov_base = (void *) buf;
 424         iov[0].iov_len = len;
 425         msg.msg_iov = iov;
 426         msg.msg_iovlen = 1;
 427
 428         switch (sock->proto) {
 429         case LTTCOMM_SOCK_UDP:
 430                 msg.msg_name = (struct sockaddr *) &sock->sockaddr.addr.sin;
 431                 msg.msg_namelen = sizeof(sock->sockaddr.addr.sin);
 432                 break;
 433         default:
 434                 break;
 435         }
 436
 437         do {
 438                 ret = sendmsg(sock->fd, &msg, flags);
 439         } while (ret < 0 && errno == EINTR);
 440         if (ret < 0) {
 441                 /*
 442                  * Only warn about EPIPE when quiet mode is deactivated.
 443                  * We consider EPIPE as expected.
 444                  */
 445                 if (errno != EPIPE || !lttng_opt_quiet) {
 446                         PERROR("sendmsg inet");
 447                 }
 448         }
 449
 450         return ret;
 451 }
 452
 453 /*
 454  * Shutdown cleanly and close.
 455  */
 456 LTTNG_HIDDEN
 457 int lttcomm_close_inet_sock(struct lttcomm_sock *sock)
 458 {
 459         int ret;
 460
 461         /* Don't try to close an invalid marked socket */
 462         if (sock->fd == -1) {
 463                 return 0;
 464         }
 465
 466         ret = close(sock->fd);
 467         if (ret) {
 468                 PERROR("close inet");
 469         }
 470
 471         /* Mark socket */
 472         sock->fd = -1;
 473
 474         return ret;
 475 }
 476
 477 /*
 478  * Return value read from /proc or else 0 if value is not found.
 479  */
 480 static unsigned long read_proc_value(const char *path)
 481 {
 482         int ret, fd;
 483         ssize_t size_ret;
 484         long r_val;
 485         unsigned long val = 0;
 486         char buf[64];
 487
 488         fd = open(path, O_RDONLY);
 489         if (fd < 0) {
 490                 goto error;
 491         }
 492
 493         size_ret = lttng_read(fd, buf, sizeof(buf));
 494         /*
 495          * Allow reading a file smaller than buf, but keep space for
 496          * final \0.
 497          */
 498         if (size_ret < 0 || size_ret >= sizeof(buf)) {
 499                 PERROR("read proc failed");
 500                 goto error_close;
 501         }
 502         buf[size_ret] = '\0';
 503
 504         errno = 0;
 505         r_val = strtol(buf, NULL, 10);
 506         if (errno != 0 || r_val < -1L) {
 507                 val = 0;
 508                 goto error_close;
 509         } else {
 510                 if (r_val > 0) {
 511                         val = r_val;
 512                 }
 513         }
 514
 515 error_close:
 516         ret = close(fd);
 517         if (ret) {
 518                 PERROR("close /proc value");
 519         }
 520 error:
 521         return val;
 522 }
 523
 524 LTTNG_HIDDEN
 525 void lttcomm_inet_init(void)
 526 {
 527         unsigned long syn_retries, fin_timeout, syn_timeout, env;
 528
 529         env = lttcomm_get_network_timeout();
 530         if (env) {
 531                 lttcomm_inet_tcp_timeout = env;
 532                 goto end;
 533         }
 534
 535         /* Assign default value and see if we can change it. */
 536         lttcomm_inet_tcp_timeout = DEFAULT_INET_TCP_TIMEOUT;
 537
 538         syn_retries = read_proc_value(LTTCOMM_INET_PROC_SYN_RETRIES_PATH);
 539         fin_timeout = read_proc_value(LTTCOMM_INET_PROC_FIN_TIMEOUT_PATH);
 540
 541         syn_timeout = syn_retries * LTTCOMM_INET_SYN_TIMEOUT_FACTOR;
 542
 543         /*
 544          * Get the maximum between the two possible timeout value and use that to
 545          * get the maximum with the default timeout.
 546          */
 547         lttcomm_inet_tcp_timeout = max_t(unsigned long,
 548                         max_t(unsigned long, syn_timeout, fin_timeout),
 549                         lttcomm_inet_tcp_timeout);
 550
 551 end:
 552         DBG("TCP inet operation timeout set to %lu sec", lttcomm_inet_tcp_timeout);
 553 }