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