src/common/relayd/relayd.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 _GNU_SOURCE
  19 #include <assert.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <sys/stat.h>
  24 #include <inttypes.h>
  25
  26 #include <common/common.h>
  27 #include <common/defaults.h>
  28 #include <common/sessiond-comm/relayd.h>
  29 #include <common/index/lttng-index.h>
  30
  31 #include "relayd.h"
  32
  33 /*
  34  * Send command. Fill up the header and append the data.
  35  */
  36 static int send_command(struct lttcomm_relayd_sock *rsock,
  37                 enum lttcomm_relayd_command cmd, void *data, size_t size,
  38                 int flags)
  39 {
  40         int ret;
  41         struct lttcomm_relayd_hdr header;
  42         char *buf;
  43         uint64_t buf_size = sizeof(header);
  44
  45         if (rsock->sock.fd < 0) {
  46                 return -ECONNRESET;
  47         }
  48
  49         if (data) {
  50                 buf_size += size;
  51         }
  52
  53         buf = zmalloc(buf_size);
  54         if (buf == NULL) {
  55                 PERROR("zmalloc relayd send command buf");
  56                 ret = -1;
  57                 goto alloc_error;
  58         }
  59
  60         header.cmd = htobe32(cmd);
  61         header.data_size = htobe64(size);
  62
  63         /* Zeroed for now since not used. */
  64         header.cmd_version = 0;
  65         header.circuit_id = 0;
  66
  67         /* Prepare buffer to send. */
  68         memcpy(buf, &header, sizeof(header));
  69         if (data) {
  70                 memcpy(buf + sizeof(header), data, size);
  71         }
  72
  73         ret = rsock->sock.ops->sendmsg(&rsock->sock, buf, buf_size, flags);
  74         if (ret < 0) {
  75                 ret = -errno;
  76                 goto error;
  77         }
  78
  79         DBG3("Relayd sending command %d of size %" PRIu64, cmd, buf_size);
  80
  81 error:
  82         free(buf);
  83 alloc_error:
  84         return ret;
  85 }
  86
  87 /*
  88  * Receive reply data on socket. This MUST be call after send_command or else
  89  * could result in unexpected behavior(s).
  90  */
  91 static int recv_reply(struct lttcomm_relayd_sock *rsock, void *data, size_t size)
  92 {
  93         int ret;
  94
  95         if (rsock->sock.fd < 0) {
  96                 return -ECONNRESET;
  97         }
  98
  99         DBG3("Relayd waiting for reply of size %zu", size);
 100
 101         ret = rsock->sock.ops->recvmsg(&rsock->sock, data, size, 0);
 102         if (ret <= 0 || ret != size) {
 103                 if (ret == 0) {
 104                         /* Orderly shutdown. */
 105                         DBG("Socket %d has performed an orderly shutdown", rsock->sock.fd);
 106                 } else {
 107                         DBG("Receiving reply failed on sock %d for size %zu with ret %d",
 108                                         rsock->sock.fd, size, ret);
 109                 }
 110                 /* Always return -1 here and the caller can use errno. */
 111                 ret = -1;
 112                 goto error;
 113         }
 114
 115 error:
 116         return ret;
 117 }
 118
 119 /*
 120  * Starting at 2.4, RELAYD_CREATE_SESSION takes additional parameters to
 121  * support the live reading capability.
 122  */
 123 static int relayd_create_session_2_4(struct lttcomm_relayd_sock *rsock,
 124                 uint64_t *session_id, char *session_name, char *hostname,
 125                 int session_live_timer, unsigned int snapshot)
 126 {
 127         int ret;
 128         struct lttcomm_relayd_create_session_2_4 msg;
 129
 130         strncpy(msg.session_name, session_name, sizeof(msg.session_name));
 131         strncpy(msg.hostname, hostname, sizeof(msg.hostname));
 132         msg.live_timer = htobe32(session_live_timer);
 133         msg.snapshot = htobe32(snapshot);
 134
 135         /* Send command */
 136         ret = send_command(rsock, RELAYD_CREATE_SESSION, &msg, sizeof(msg), 0);
 137         if (ret < 0) {
 138                 goto error;
 139         }
 140
 141 error:
 142         return ret;
 143 }
 144
 145 /*
 146  * RELAYD_CREATE_SESSION from 2.1 to 2.3.
 147  */
 148 static int relayd_create_session_2_1(struct lttcomm_relayd_sock *rsock,
 149                 uint64_t *session_id)
 150 {
 151         int ret;
 152
 153         /* Send command */
 154         ret = send_command(rsock, RELAYD_CREATE_SESSION, NULL, 0, 0);
 155         if (ret < 0) {
 156                 goto error;
 157         }
 158
 159 error:
 160         return ret;
 161 }
 162
 163 /*
 164  * Send a RELAYD_CREATE_SESSION command to the relayd with the given socket and
 165  * set session_id of the relayd if we have a successful reply from the relayd.
 166  *
 167  * On success, return 0 else a negative value which is either an errno error or
 168  * a lttng error code from the relayd.
 169  */
 170 int relayd_create_session(struct lttcomm_relayd_sock *rsock, uint64_t *session_id,
 171                 char *session_name, char *hostname, int session_live_timer,
 172                 unsigned int snapshot)
 173 {
 174         int ret;
 175         struct lttcomm_relayd_status_session reply;
 176
 177         assert(rsock);
 178         assert(session_id);
 179
 180         DBG("Relayd create session");
 181
 182         switch(rsock->minor) {
 183                 case 1:
 184                 case 2:
 185                 case 3:
 186                         ret = relayd_create_session_2_1(rsock, session_id);
 187                 case 4:
 188                 default:
 189                         ret = relayd_create_session_2_4(rsock, session_id, session_name,
 190                                         hostname, session_live_timer, snapshot);
 191         }
 192
 193         if (ret < 0) {
 194                 goto error;
 195         }
 196
 197         /* Receive response */
 198         ret = recv_reply(rsock, (void *) &reply, sizeof(reply));
 199         if (ret < 0) {
 200                 goto error;
 201         }
 202
 203         reply.session_id = be64toh(reply.session_id);
 204         reply.ret_code = be32toh(reply.ret_code);
 205
 206         /* Return session id or negative ret code. */
 207         if (reply.ret_code != LTTNG_OK) {
 208                 ret = -1;
 209                 ERR("Relayd create session replied error %d", reply.ret_code);
 210                 goto error;
 211         } else {
 212                 ret = 0;
 213                 *session_id = reply.session_id;
 214         }
 215
 216         DBG("Relayd session created with id %" PRIu64, reply.session_id);
 217
 218 error:
 219         return ret;
 220 }
 221
 222 /*
 223  * Add stream on the relayd and assign stream handle to the stream_id argument.
 224  *
 225  * On success return 0 else return ret_code negative value.
 226  */
 227 int relayd_add_stream(struct lttcomm_relayd_sock *rsock, const char *channel_name,
 228                 const char *pathname, uint64_t *stream_id,
 229                 uint64_t tracefile_size, uint64_t tracefile_count)
 230 {
 231         int ret;
 232         struct lttcomm_relayd_add_stream msg;
 233         struct lttcomm_relayd_add_stream_2_2 msg_2_2;
 234         struct lttcomm_relayd_status_stream reply;
 235
 236         /* Code flow error. Safety net. */
 237         assert(rsock);
 238         assert(channel_name);
 239         assert(pathname);
 240
 241         DBG("Relayd adding stream for channel name %s", channel_name);
 242
 243         /* Compat with relayd 2.1 */
 244         if (rsock->minor == 1) {
 245                 strncpy(msg.channel_name, channel_name, sizeof(msg.channel_name));
 246                 strncpy(msg.pathname, pathname, sizeof(msg.pathname));
 247
 248                 /* Send command */
 249                 ret = send_command(rsock, RELAYD_ADD_STREAM, (void *) &msg, sizeof(msg), 0);
 250                 if (ret < 0) {
 251                         goto error;
 252                 }
 253         } else {
 254                 /* Compat with relayd 2.2+ */
 255                 strncpy(msg_2_2.channel_name, channel_name, sizeof(msg_2_2.channel_name));
 256                 strncpy(msg_2_2.pathname, pathname, sizeof(msg_2_2.pathname));
 257                 msg_2_2.tracefile_size = htobe64(tracefile_size);
 258                 msg_2_2.tracefile_count = htobe64(tracefile_count);
 259
 260                 /* Send command */
 261                 ret = send_command(rsock, RELAYD_ADD_STREAM, (void *) &msg_2_2, sizeof(msg_2_2), 0);
 262                 if (ret < 0) {
 263                         goto error;
 264                 }
 265         }
 266
 267         /* Waiting for reply */
 268         ret = recv_reply(rsock, (void *) &reply, sizeof(reply));
 269         if (ret < 0) {
 270                 goto error;
 271         }
 272
 273         /* Back to host bytes order. */
 274         reply.handle = be64toh(reply.handle);
 275         reply.ret_code = be32toh(reply.ret_code);
 276
 277         /* Return session id or negative ret code. */
 278         if (reply.ret_code != LTTNG_OK) {
 279                 ret = -1;
 280                 ERR("Relayd add stream replied error %d", reply.ret_code);
 281         } else {
 282                 /* Success */
 283                 ret = 0;
 284                 *stream_id = reply.handle;
 285         }
 286
 287         DBG("Relayd stream added successfully with handle %" PRIu64,
 288                 reply.handle);
 289
 290 error:
 291         return ret;
 292 }
 293
 294 /*
 295  * Check version numbers on the relayd.
 296  * If major versions are compatible, we assign minor_to_use to the
 297  * minor version of the procotol we are going to use for this session.
 298  *
 299  * Return 0 if compatible else negative value.
 300  */
 301 int relayd_version_check(struct lttcomm_relayd_sock *rsock)
 302 {
 303         int ret;
 304         struct lttcomm_relayd_version msg;
 305
 306         /* Code flow error. Safety net. */
 307         assert(rsock);
 308
 309         DBG("Relayd version check for major.minor %u.%u", rsock->major,
 310                         rsock->minor);
 311
 312         /* Prepare network byte order before transmission. */
 313         msg.major = htobe32(rsock->major);
 314         msg.minor = htobe32(rsock->minor);
 315
 316         /* Send command */
 317         ret = send_command(rsock, RELAYD_VERSION, (void *) &msg, sizeof(msg), 0);
 318         if (ret < 0) {
 319                 goto error;
 320         }
 321
 322         /* Receive response */
 323         ret = recv_reply(rsock, (void *) &msg, sizeof(msg));
 324         if (ret < 0) {
 325                 goto error;
 326         }
 327
 328         /* Set back to host bytes order */
 329         msg.major = be32toh(msg.major);
 330         msg.minor = be32toh(msg.minor);
 331
 332         /*
 333          * Only validate the major version. If the other side is higher,
 334          * communication is not possible. Only major version equal can talk to each
 335          * other. If the minor version differs, the lowest version is used by both
 336          * sides.
 337          */
 338         if (msg.major != rsock->major) {
 339                 /* Not compatible */
 340                 ret = -1;
 341                 DBG2("Relayd version is NOT compatible. Relayd version %u != %u (us)",
 342                                 msg.major, rsock->major);
 343                 goto error;
 344         }
 345
 346         /*
 347          * If the relayd's minor version is higher, it will adapt to our version so
 348          * we can continue to use the latest relayd communication data structure.
 349          * If the received minor version is higher, the relayd should adapt to us.
 350          */
 351         if (rsock->minor > msg.minor) {
 352                 rsock->minor = msg.minor;
 353         }
 354
 355         /* Version number compatible */
 356         DBG2("Relayd version is compatible, using protocol version %u.%u",
 357                         rsock->major, rsock->minor);
 358         ret = 0;
 359
 360 error:
 361         return ret;
 362 }
 363
 364 /*
 365  * Add stream on the relayd and assign stream handle to the stream_id argument.
 366  *
 367  * On success return 0 else return ret_code negative value.
 368  */
 369 int relayd_send_metadata(struct lttcomm_relayd_sock *rsock, size_t len)
 370 {
 371         int ret;
 372
 373         /* Code flow error. Safety net. */
 374         assert(rsock);
 375
 376         DBG("Relayd sending metadata of size %zu", len);
 377
 378         /* Send command */
 379         ret = send_command(rsock, RELAYD_SEND_METADATA, NULL, len, 0);
 380         if (ret < 0) {
 381                 goto error;
 382         }
 383
 384         DBG2("Relayd metadata added successfully");
 385
 386         /*
 387          * After that call, the metadata data MUST be sent to the relayd so the
 388          * receive size on the other end matches the len of the metadata packet
 389          * header. This is why we don't wait for a reply here.
 390          */
 391
 392 error:
 393         return ret;
 394 }
 395
 396 /*
 397  * Connect to relay daemon with an allocated lttcomm_relayd_sock.
 398  */
 399 int relayd_connect(struct lttcomm_relayd_sock *rsock)
 400 {
 401         /* Code flow error. Safety net. */
 402         assert(rsock);
 403
 404         if (!rsock->sock.ops) {
 405                 /*
 406                  * Attempting a connect on a non-initialized socket.
 407                  */
 408                 return -ECONNRESET;
 409         }
 410
 411         DBG3("Relayd connect ...");
 412
 413         return rsock->sock.ops->connect(&rsock->sock);
 414 }
 415
 416 /*
 417  * Close relayd socket with an allocated lttcomm_relayd_sock.
 418  *
 419  * If no socket operations are found, simply return 0 meaning that everything
 420  * is fine. Without operations, the socket can not possibly be opened or used.
 421  * This is possible if the socket was allocated but not created. However, the
 422  * caller could simply use it to store a valid file descriptor for instance
 423  * passed over a Unix socket and call this to cleanup but still without a valid
 424  * ops pointer.
 425  *
 426  * Return the close returned value. On error, a negative value is usually
 427  * returned back from close(2).
 428  */
 429 int relayd_close(struct lttcomm_relayd_sock *rsock)
 430 {
 431         int ret;
 432
 433         /* Code flow error. Safety net. */
 434         assert(rsock);
 435
 436         /* An invalid fd is fine, return success. */
 437         if (rsock->sock.fd < 0) {
 438                 ret = 0;
 439                 goto end;
 440         }
 441
 442         DBG3("Relayd closing socket %d", rsock->sock.fd);
 443
 444         if (rsock->sock.ops) {
 445                 ret = rsock->sock.ops->close(&rsock->sock);
 446         } else {
 447                 /* Default call if no specific ops found. */
 448                 ret = close(rsock->sock.fd);
 449                 if (ret < 0) {
 450                         PERROR("relayd_close default close");
 451                 }
 452         }
 453         rsock->sock.fd = -1;
 454
 455 end:
 456         return ret;
 457 }
 458
 459 /*
 460  * Send data header structure to the relayd.
 461  */
 462 int relayd_send_data_hdr(struct lttcomm_relayd_sock *rsock,
 463                 struct lttcomm_relayd_data_hdr *hdr, size_t size)
 464 {
 465         int ret;
 466
 467         /* Code flow error. Safety net. */
 468         assert(rsock);
 469         assert(hdr);
 470
 471         if (rsock->sock.fd < 0) {
 472                 return -ECONNRESET;
 473         }
 474
 475         DBG3("Relayd sending data header of size %zu", size);
 476
 477         /* Again, safety net */
 478         if (size == 0) {
 479                 size = sizeof(struct lttcomm_relayd_data_hdr);
 480         }
 481
 482         /* Only send data header. */
 483         ret = rsock->sock.ops->sendmsg(&rsock->sock, hdr, size, 0);
 484         if (ret < 0) {
 485                 ret = -errno;
 486                 goto error;
 487         }
 488
 489         /*
 490          * The data MUST be sent right after that command for the receive on the
 491          * other end to match the size in the header.
 492          */
 493
 494 error:
 495         return ret;
 496 }
 497
 498 /*
 499  * Send close stream command to the relayd.
 500  */
 501 int relayd_send_close_stream(struct lttcomm_relayd_sock *rsock, uint64_t stream_id,
 502                 uint64_t last_net_seq_num)
 503 {
 504         int ret;
 505         struct lttcomm_relayd_close_stream msg;
 506         struct lttcomm_relayd_generic_reply reply;
 507
 508         /* Code flow error. Safety net. */
 509         assert(rsock);
 510
 511         DBG("Relayd closing stream id %" PRIu64, stream_id);
 512
 513         msg.stream_id = htobe64(stream_id);
 514         msg.last_net_seq_num = htobe64(last_net_seq_num);
 515
 516         /* Send command */
 517         ret = send_command(rsock, RELAYD_CLOSE_STREAM, (void *) &msg, sizeof(msg), 0);
 518         if (ret < 0) {
 519                 goto error;
 520         }
 521
 522         /* Receive response */
 523         ret = recv_reply(rsock, (void *) &reply, sizeof(reply));
 524         if (ret < 0) {
 525                 goto error;
 526         }
 527
 528         reply.ret_code = be32toh(reply.ret_code);
 529
 530         /* Return session id or negative ret code. */
 531         if (reply.ret_code != LTTNG_OK) {
 532                 ret = -1;
 533                 ERR("Relayd close stream replied error %d", reply.ret_code);
 534         } else {
 535                 /* Success */
 536                 ret = 0;
 537         }
 538
 539         DBG("Relayd close stream id %" PRIu64 " successfully", stream_id);
 540
 541 error:
 542         return ret;
 543 }
 544
 545 /*
 546  * Check for data availability for a given stream id.
 547  *
 548  * Return 0 if NOT pending, 1 if so and a negative value on error.
 549  */
 550 int relayd_data_pending(struct lttcomm_relayd_sock *rsock, uint64_t stream_id,
 551                 uint64_t last_net_seq_num)
 552 {
 553         int ret;
 554         struct lttcomm_relayd_data_pending msg;
 555         struct lttcomm_relayd_generic_reply reply;
 556
 557         /* Code flow error. Safety net. */
 558         assert(rsock);
 559
 560         DBG("Relayd data pending for stream id %" PRIu64, stream_id);
 561
 562         msg.stream_id = htobe64(stream_id);
 563         msg.last_net_seq_num = htobe64(last_net_seq_num);
 564
 565         /* Send command */
 566         ret = send_command(rsock, RELAYD_DATA_PENDING, (void *) &msg,
 567                         sizeof(msg), 0);
 568         if (ret < 0) {
 569                 goto error;
 570         }
 571
 572         /* Receive response */
 573         ret = recv_reply(rsock, (void *) &reply, sizeof(reply));
 574         if (ret < 0) {
 575                 goto error;
 576         }
 577
 578         reply.ret_code = be32toh(reply.ret_code);
 579
 580         /* Return session id or negative ret code. */
 581         if (reply.ret_code >= LTTNG_OK) {
 582                 ERR("Relayd data pending replied error %d", reply.ret_code);
 583         }
 584
 585         /* At this point, the ret code is either 1 or 0 */
 586         ret = reply.ret_code;
 587
 588         DBG("Relayd data is %s pending for stream id %" PRIu64,
 589                         ret == 1 ? "" : "NOT", stream_id);
 590
 591 error:
 592         return ret;
 593 }
 594
 595 /*
 596  * Check on the relayd side for a quiescent state on the control socket.
 597  */
 598 int relayd_quiescent_control(struct lttcomm_relayd_sock *rsock,
 599                 uint64_t metadata_stream_id)
 600 {
 601         int ret;
 602         struct lttcomm_relayd_quiescent_control msg;
 603         struct lttcomm_relayd_generic_reply reply;
 604
 605         /* Code flow error. Safety net. */
 606         assert(rsock);
 607
 608         DBG("Relayd checking quiescent control state");
 609
 610         msg.stream_id = htobe64(metadata_stream_id);
 611
 612         /* Send command */
 613         ret = send_command(rsock, RELAYD_QUIESCENT_CONTROL, &msg, sizeof(msg), 0);
 614         if (ret < 0) {
 615                 goto error;
 616         }
 617
 618         /* Receive response */
 619         ret = recv_reply(rsock, (void *) &reply, sizeof(reply));
 620         if (ret < 0) {
 621                 goto error;
 622         }
 623
 624         reply.ret_code = be32toh(reply.ret_code);
 625
 626         /* Return session id or negative ret code. */
 627         if (reply.ret_code != LTTNG_OK) {
 628                 ret = -1;
 629                 ERR("Relayd quiescent control replied error %d", reply.ret_code);
 630                 goto error;
 631         }
 632
 633         /* Control socket is quiescent */
 634         return 0;
 635
 636 error:
 637         return ret;
 638 }
 639
 640 /*
 641  * Begin a data pending command for a specific session id.
 642  */
 643 int relayd_begin_data_pending(struct lttcomm_relayd_sock *rsock, uint64_t id)
 644 {
 645         int ret;
 646         struct lttcomm_relayd_begin_data_pending msg;
 647         struct lttcomm_relayd_generic_reply reply;
 648
 649         /* Code flow error. Safety net. */
 650         assert(rsock);
 651
 652         DBG("Relayd begin data pending");
 653
 654         msg.session_id = htobe64(id);
 655
 656         /* Send command */
 657         ret = send_command(rsock, RELAYD_BEGIN_DATA_PENDING, &msg, sizeof(msg), 0);
 658         if (ret < 0) {
 659                 goto error;
 660         }
 661
 662         /* Receive response */
 663         ret = recv_reply(rsock, (void *) &reply, sizeof(reply));
 664         if (ret < 0) {
 665                 goto error;
 666         }
 667
 668         reply.ret_code = be32toh(reply.ret_code);
 669
 670         /* Return session id or negative ret code. */
 671         if (reply.ret_code != LTTNG_OK) {
 672                 ret = -1;
 673                 ERR("Relayd begin data pending replied error %d", reply.ret_code);
 674                 goto error;
 675         }
 676
 677         return 0;
 678
 679 error:
 680         return ret;
 681 }
 682
 683 /*
 684  * End a data pending command for a specific session id.
 685  *
 686  * Return 0 on success and set is_data_inflight to 0 if no data is being
 687  * streamed or 1 if it is the case.
 688  */
 689 int relayd_end_data_pending(struct lttcomm_relayd_sock *rsock, uint64_t id,
 690                 unsigned int *is_data_inflight)
 691 {
 692         int ret;
 693         struct lttcomm_relayd_end_data_pending msg;
 694         struct lttcomm_relayd_generic_reply reply;
 695
 696         /* Code flow error. Safety net. */
 697         assert(rsock);
 698
 699         DBG("Relayd end data pending");
 700
 701         msg.session_id = htobe64(id);
 702
 703         /* Send command */
 704         ret = send_command(rsock, RELAYD_END_DATA_PENDING, &msg, sizeof(msg), 0);
 705         if (ret < 0) {
 706                 goto error;
 707         }
 708
 709         /* Receive response */
 710         ret = recv_reply(rsock, (void *) &reply, sizeof(reply));
 711         if (ret < 0) {
 712                 goto error;
 713         }
 714
 715         reply.ret_code = be32toh(reply.ret_code);
 716         if (reply.ret_code < 0) {
 717                 ret = reply.ret_code;
 718                 goto error;
 719         }
 720
 721         *is_data_inflight = reply.ret_code;
 722
 723         DBG("Relayd end data pending is data inflight: %d", reply.ret_code);
 724
 725         return 0;
 726
 727 error:
 728         return ret;
 729 }
 730
 731 /*
 732  * Send index to the relayd.
 733  */
 734 int relayd_send_index(struct lttcomm_relayd_sock *rsock,
 735                 struct lttng_packet_index *index, uint64_t relay_stream_id,
 736                 uint64_t net_seq_num)
 737 {
 738         int ret;
 739         struct lttcomm_relayd_index msg;
 740         struct lttcomm_relayd_generic_reply reply;
 741
 742         /* Code flow error. Safety net. */
 743         assert(rsock);
 744
 745         if (rsock->minor < 4) {
 746                 DBG("Not sending indexes before protocol 2.4");
 747                 ret = 0;
 748                 goto error;
 749         }
 750
 751         DBG("Relayd sending index for stream ID %" PRIu64, relay_stream_id);
 752
 753         msg.relay_stream_id = htobe64(relay_stream_id);
 754         msg.net_seq_num = htobe64(net_seq_num);
 755
 756         /* The index is already in big endian. */
 757         msg.packet_size = index->packet_size;
 758         msg.content_size = index->content_size;
 759         msg.timestamp_begin = index->timestamp_begin;
 760         msg.timestamp_end = index->timestamp_end;
 761         msg.events_discarded = index->events_discarded;
 762         msg.stream_id = index->stream_id;
 763
 764         /* Send command */
 765         ret = send_command(rsock, RELAYD_SEND_INDEX, &msg, sizeof(msg), 0);
 766         if (ret < 0) {
 767                 goto error;
 768         }
 769
 770         /* Receive response */
 771         ret = recv_reply(rsock, (void *) &reply, sizeof(reply));
 772         if (ret < 0) {
 773                 goto error;
 774         }
 775
 776         reply.ret_code = be32toh(reply.ret_code);
 777
 778         /* Return session id or negative ret code. */
 779         if (reply.ret_code != LTTNG_OK) {
 780                 ret = -1;
 781                 ERR("Relayd send index replied error %d", reply.ret_code);
 782         } else {
 783                 /* Success */
 784                 ret = 0;
 785         }
 786
 787 error:
 788         return ret;
 789 }