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