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