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 *) ALIGNED_CONST_PTR(
 105                                         sock->sockaddr.addr.sin),
 106                         sizeof(sock->sockaddr.addr.sin));
 107 }
 108
 109 static
 110 int connect_no_timeout(struct lttcomm_sock *sock)
 111 {
 112         return connect(sock->fd,
 113                         (const struct sockaddr *) ALIGNED_CONST_PTR(
 114                                         sock->sockaddr.addr.sin),
 115                         sizeof(sock->sockaddr.addr.sin));
 116 }
 117
 118 static
 119 int connect_with_timeout(struct lttcomm_sock *sock)
 120 {
 121         unsigned long timeout = lttcomm_get_network_timeout();
 122         int ret, flags, connect_ret;
 123         struct timespec orig_time, cur_time;
 124         unsigned long diff_ms;
 125
 126         ret = fcntl(sock->fd, F_GETFL, 0);
 127         if (ret == -1) {
 128                 PERROR("fcntl");
 129                 return -1;
 130         }
 131         flags = ret;
 132
 133         /* Set socket to nonblock */
 134         ret = fcntl(sock->fd, F_SETFL, flags | O_NONBLOCK);
 135         if (ret == -1) {
 136                 PERROR("fcntl");
 137                 return -1;
 138         }
 139
 140         ret = lttng_clock_gettime(CLOCK_MONOTONIC, &orig_time);
 141         if (ret == -1) {
 142                 PERROR("clock_gettime");
 143                 return -1;
 144         }
 145
 146         connect_ret = connect(sock->fd,
 147                         (const struct sockaddr *) ALIGNED_CONST_PTR(
 148                                         sock->sockaddr.addr.sin),
 149                         sizeof(sock->sockaddr.addr.sin));
 150         if (connect_ret == -1 && errno != EAGAIN && errno != EWOULDBLOCK &&
 151                         errno != EINPROGRESS) {
 152                 goto error;
 153         } else if (!connect_ret) {
 154                 /* Connect succeeded */
 155                 goto success;
 156         }
 157
 158         DBG("Asynchronous connect for sock %d, performing polling with"
 159                         " timeout: %lums", sock->fd, timeout);
 160         /*
 161          * Perform poll loop following EINPROGRESS recommendation from
 162          * connect(2) man page.
 163          */
 164         do {
 165                 struct pollfd fds;
 166
 167                 fds.fd = sock->fd;
 168                 fds.events = POLLOUT;
 169                 fds.revents = 0;
 170                 ret = poll(&fds, 1, RECONNECT_DELAY);
 171                 if (ret < 0) {
 172                         goto error;
 173                 } else if (ret > 0) {
 174                         int optval;
 175                         socklen_t optval_len = sizeof(optval);
 176
 177                         if (!(fds.revents & POLLOUT)) {
 178                                 /* Either hup or error */
 179                                 errno = EPIPE;
 180                                 goto error;
 181                         }
 182                         /* got something */
 183                         ret = getsockopt(sock->fd, SOL_SOCKET,
 184                                 SO_ERROR, &optval, &optval_len);
 185                         if (ret) {
 186                                 PERROR("getsockopt");
 187                                 goto error;
 188                         }
 189                         if (!optval) {
 190                                 connect_ret = 0;
 191                                 goto success;
 192                         } else {
 193                                 /* Get actual connect() errno from opt_val */
 194                                 errno = optval;
 195                                 goto error;
 196                         }
 197                 }
 198                 /* ret == 0: timeout */
 199                 ret = lttng_clock_gettime(CLOCK_MONOTONIC, &cur_time);
 200                 if (ret == -1) {
 201                         PERROR("clock_gettime");
 202                         connect_ret = ret;
 203                         goto error;
 204                 }
 205                 if (timespec_to_ms(timespec_abs_diff(cur_time, orig_time), &diff_ms) < 0) {
 206                         ERR("timespec_to_ms input overflows milliseconds output");
 207                         connect_ret = -1;
 208                         goto error;
 209                 }
 210         } while (diff_ms < timeout);
 211
 212         /* Timeout */
 213         errno = ETIMEDOUT;
 214         connect_ret = -1;
 215
 216 success:
 217         /* Restore initial flags */
 218         ret = fcntl(sock->fd, F_SETFL, flags);
 219         if (ret == -1) {
 220                 PERROR("fcntl");
 221                 /* Continue anyway */
 222         }
 223 error:
 224         return connect_ret;
 225 }
 226
 227 /*
 228  * Connect PF_INET socket.
 229  */
 230 LTTNG_HIDDEN
 231 int lttcomm_connect_inet_sock(struct lttcomm_sock *sock)
 232 {
 233         int ret, closeret;
 234
 235         if (lttcomm_get_network_timeout()) {
 236                 ret = connect_with_timeout(sock);
 237         } else {
 238                 ret = connect_no_timeout(sock);
 239         }
 240         if (ret < 0) {
 241                 PERROR("connect");
 242                 goto error_connect;
 243         }
 244
 245         return ret;
 246
 247 error_connect:
 248         closeret = close(sock->fd);
 249         if (closeret) {
 250                 PERROR("close inet");
 251         }
 252
 253         return ret;
 254 }
 255
 256 /*
 257  * Do an accept(2) on the sock and return the new lttcomm socket. The socket
 258  * MUST be bind(2) before.
 259  */
 260 LTTNG_HIDDEN
 261 struct lttcomm_sock *lttcomm_accept_inet_sock(struct lttcomm_sock *sock)
 262 {
 263         int new_fd;
 264         socklen_t len;
 265         struct lttcomm_sock *new_sock;
 266         unsigned long timeout;
 267         struct sockaddr_in new_addr = {};
 268
 269         if (sock->proto == LTTCOMM_SOCK_UDP) {
 270                 /*
 271                  * accept(2) does not exist for UDP so simply return the passed socket.
 272                  */
 273                 new_sock = sock;
 274                 goto end;
 275         }
 276
 277         new_sock = lttcomm_alloc_sock(sock->proto);
 278         if (new_sock == NULL) {
 279                 goto error;
 280         }
 281
 282         len = sizeof(new_addr);
 283
 284         /* Blocking call */
 285         new_fd = accept(sock->fd, (struct sockaddr *) &new_addr, &len);
 286         if (new_fd < 0) {
 287                 PERROR("accept inet");
 288                 goto error;
 289         }
 290         new_sock->sockaddr.addr.sin = new_addr;
 291         timeout = lttcomm_get_network_timeout();
 292         if (timeout) {
 293                 int ret;
 294
 295                 ret = lttcomm_setsockopt_rcv_timeout(new_fd, timeout);
 296                 if (ret) {
 297                         goto error_close;
 298                 }
 299                 ret = lttcomm_setsockopt_snd_timeout(new_fd, timeout);
 300                 if (ret) {
 301                         goto error_close;
 302                 }
 303         }
 304
 305         new_sock->fd = new_fd;
 306         new_sock->ops = &inet_ops;
 307
 308 end:
 309         return new_sock;
 310
 311 error_close:
 312         if (close(new_fd) < 0) {
 313                 PERROR("accept inet close fd");
 314         }
 315
 316 error:
 317         free(new_sock);
 318         return NULL;
 319 }
 320
 321 /*
 322  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 323  */
 324 LTTNG_HIDDEN
 325 int lttcomm_listen_inet_sock(struct lttcomm_sock *sock, int backlog)
 326 {
 327         int ret;
 328
 329         if (sock->proto == LTTCOMM_SOCK_UDP) {
 330                 /* listen(2) does not exist for UDP so simply return success. */
 331                 ret = 0;
 332                 goto end;
 333         }
 334
 335         /* Default listen backlog */
 336         if (backlog <= 0) {
 337                 backlog = LTTNG_SESSIOND_COMM_MAX_LISTEN;
 338         }
 339
 340         ret = listen(sock->fd, backlog);
 341         if (ret < 0) {
 342                 PERROR("listen inet");
 343         }
 344
 345 end:
 346         return ret;
 347 }
 348
 349 /*
 350  * Receive data of size len in put that data into the buf param. Using recvmsg
 351  * API.
 352  *
 353  * Return the size of received data.
 354  */
 355 LTTNG_HIDDEN
 356 ssize_t lttcomm_recvmsg_inet_sock(struct lttcomm_sock *sock, void *buf,
 357                 size_t len, int flags)
 358 {
 359         struct msghdr msg;
 360         struct iovec iov[1];
 361         ssize_t ret = -1;
 362         size_t len_last;
 363         struct sockaddr_in addr = sock->sockaddr.addr.sin;
 364
 365         memset(&msg, 0, sizeof(msg));
 366
 367         iov[0].iov_base = buf;
 368         iov[0].iov_len = len;
 369         msg.msg_iov = iov;
 370         msg.msg_iovlen = 1;
 371
 372         msg.msg_name = (struct sockaddr *) &addr;
 373         msg.msg_namelen = sizeof(sock->sockaddr.addr.sin);
 374
 375         do {
 376                 len_last = iov[0].iov_len;
 377                 ret = recvmsg(sock->fd, &msg, flags);
 378                 if (ret > 0) {
 379                         if (flags & MSG_DONTWAIT) {
 380                                 goto end;
 381                         }
 382                         iov[0].iov_base += ret;
 383                         iov[0].iov_len -= ret;
 384                         assert(ret <= len_last);
 385                 }
 386         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 387
 388         if (ret < 0) {
 389                 if (errno == EAGAIN && flags & MSG_DONTWAIT) {
 390                         /*
 391                          * EAGAIN is expected in non-blocking mode and should
 392                          * not be reported as an error. Moreover, if no data
 393                          * was read, 0 must not be returned as it would be
 394                          * interpreted as an orderly shutdown of the socket.
 395                          */
 396                         goto end;
 397                 }
 398                 PERROR("recvmsg inet");
 399         } else if (ret > 0) {
 400                 ret = len;
 401         }
 402         /* Else ret = 0 meaning an orderly shutdown. */
 403 end:
 404         return ret;
 405 }
 406
 407 /*
 408  * Send buf data of size len. Using sendmsg API.
 409  *
 410  * Return the size of sent data.
 411  */
 412 LTTNG_HIDDEN
 413 ssize_t lttcomm_sendmsg_inet_sock(struct lttcomm_sock *sock, const void *buf,
 414                 size_t len, int flags)
 415 {
 416         struct msghdr msg;
 417         struct iovec iov[1];
 418         ssize_t ret = -1;
 419
 420         memset(&msg, 0, sizeof(msg));
 421
 422         iov[0].iov_base = (void *) buf;
 423         iov[0].iov_len = len;
 424         msg.msg_iov = iov;
 425         msg.msg_iovlen = 1;
 426
 427         switch (sock->proto) {
 428         case LTTCOMM_SOCK_UDP:
 429         {
 430                 struct sockaddr_in addr = sock->sockaddr.addr.sin;
 431
 432                 msg.msg_name = (struct sockaddr *) &addr;
 433                 msg.msg_namelen = sizeof(sock->sockaddr.addr.sin);
 434                 break;
 435         }
 436         default:
 437                 break;
 438         }
 439
 440         do {
 441                 ret = sendmsg(sock->fd, &msg, flags);
 442         } while (ret < 0 && errno == EINTR);
 443         if (ret < 0) {
 444                 /*
 445                  * Only warn about EPIPE when quiet mode is deactivated.
 446                  * We consider EPIPE as expected.
 447                  */
 448                 if (errno != EPIPE || !lttng_opt_quiet) {
 449                         PERROR("sendmsg inet");
 450                 }
 451         }
 452
 453         return ret;
 454 }
 455
 456 /*
 457  * Shutdown cleanly and close.
 458  */
 459 LTTNG_HIDDEN
 460 int lttcomm_close_inet_sock(struct lttcomm_sock *sock)
 461 {
 462         int ret;
 463
 464         /* Don't try to close an invalid marked socket */
 465         if (sock->fd == -1) {
 466                 return 0;
 467         }
 468
 469         ret = close(sock->fd);
 470         if (ret) {
 471                 PERROR("close inet");
 472         }
 473
 474         /* Mark socket */
 475         sock->fd = -1;
 476
 477         return ret;
 478 }
 479
 480 /*
 481  * Return value read from /proc or else 0 if value is not found.
 482  */
 483 static unsigned long read_proc_value(const char *path)
 484 {
 485         int ret, fd;
 486         ssize_t size_ret;
 487         long r_val;
 488         unsigned long val = 0;
 489         char buf[64];
 490
 491         fd = open(path, O_RDONLY);
 492         if (fd < 0) {
 493                 goto error;
 494         }
 495
 496         size_ret = lttng_read(fd, buf, sizeof(buf));
 497         /*
 498          * Allow reading a file smaller than buf, but keep space for
 499          * final \0.
 500          */
 501         if (size_ret < 0 || size_ret >= sizeof(buf)) {
 502                 PERROR("read proc failed");
 503                 goto error_close;
 504         }
 505         buf[size_ret] = '\0';
 506
 507         errno = 0;
 508         r_val = strtol(buf, NULL, 10);
 509         if (errno != 0 || r_val < -1L) {
 510                 val = 0;
 511                 goto error_close;
 512         } else {
 513                 if (r_val > 0) {
 514                         val = r_val;
 515                 }
 516         }
 517
 518 error_close:
 519         ret = close(fd);
 520         if (ret) {
 521                 PERROR("close /proc value");
 522         }
 523 error:
 524         return val;
 525 }
 526
 527 LTTNG_HIDDEN
 528 void lttcomm_inet_init(void)
 529 {
 530         unsigned long syn_retries, fin_timeout, syn_timeout, env;
 531
 532         env = lttcomm_get_network_timeout();
 533         if (env) {
 534                 lttcomm_inet_tcp_timeout = env;
 535                 goto end;
 536         }
 537
 538         /* Assign default value and see if we can change it. */
 539         lttcomm_inet_tcp_timeout = DEFAULT_INET_TCP_TIMEOUT;
 540
 541         syn_retries = read_proc_value(LTTCOMM_INET_PROC_SYN_RETRIES_PATH);
 542         fin_timeout = read_proc_value(LTTCOMM_INET_PROC_FIN_TIMEOUT_PATH);
 543
 544         syn_timeout = syn_retries * LTTCOMM_INET_SYN_TIMEOUT_FACTOR;
 545
 546         /*
 547          * Get the maximum between the two possible timeout value and use that to
 548          * get the maximum with the default timeout.
 549          */
 550         lttcomm_inet_tcp_timeout = max_t(unsigned long,
 551                         max_t(unsigned long, syn_timeout, fin_timeout),
 552                         lttcomm_inet_tcp_timeout);
 553
 554 end:
 555         DBG("TCP inet operation timeout set to %lu sec", lttcomm_inet_tcp_timeout);
 556 }