lib/libwebsockets.c

   1 /*
   2  * libwebsockets - small server side websockets and web server implementation
   3  *
   4  * Copyright (C) 2010 Andy Green <andy@warmcat.com>
   5  *
   6  *  This library is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU Lesser General Public
   8  *  License as published by the Free Software Foundation:
   9  *  version 2.1 of the License.
  10  *
  11  *  This library is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *  Lesser General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Lesser General Public
  17  *  License along with this library; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  19  *  MA  02110-1301  USA
  20  */
  21
  22 #include "private-libwebsockets.h"
  23
  24 /* file descriptor hash management */
  25
  26 struct libwebsocket *
  27 wsi_from_fd(struct libwebsocket_context *this, int fd)
  28 {
  29         int h = LWS_FD_HASH(fd);
  30         int n = 0;
  31
  32         for (n = 0; n < this->fd_hashtable[h].length; n++)
  33                 if (this->fd_hashtable[h].wsi[n]->sock == fd)
  34                         return this->fd_hashtable[h].wsi[n];
  35
  36         return NULL;
  37 }
  38
  39 int
  40 insert_wsi(struct libwebsocket_context *this, struct libwebsocket *wsi)
  41 {
  42         int h = LWS_FD_HASH(wsi->sock);
  43
  44         if (this->fd_hashtable[h].length == MAX_CLIENTS - 1) {
  45                 fprintf(stderr, "hash table overflow\n");
  46                 return 1;
  47         }
  48
  49         this->fd_hashtable[h].wsi[this->fd_hashtable[h].length++] = wsi;
  50
  51         return 0;
  52 }
  53
  54 int
  55 delete_from_fd(struct libwebsocket_context *this, int fd)
  56 {
  57         int h = LWS_FD_HASH(fd);
  58         int n = 0;
  59
  60         for (n = 0; n < this->fd_hashtable[h].length; n++)
  61                 if (this->fd_hashtable[h].wsi[n]->sock == fd) {
  62                         while (n < this->fd_hashtable[h].length) {
  63                                 this->fd_hashtable[h].wsi[n] =
  64                                                this->fd_hashtable[h].wsi[n + 1];
  65                                 n++;
  66                         }
  67                         this->fd_hashtable[h].length--;
  68
  69                         return 0;
  70                 }
  71
  72         fprintf(stderr, "Failed to find fd %d requested for "
  73                                                    "delete in hashtable\n", fd);
  74         return 1;
  75 }
  76
  77
  78 void
  79 libwebsocket_close_and_free_session(struct libwebsocket *wsi)
  80 {
  81         int n;
  82         unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + 2 +
  83                                                   LWS_SEND_BUFFER_POST_PADDING];
  84
  85         if ((unsigned long)wsi < LWS_MAX_PROTOCOLS)
  86                 return;
  87
  88         n = wsi->state;
  89
  90         if (n == WSI_STATE_DEAD_SOCKET)
  91                 return;
  92
  93         /*
  94          * signal we are closing, libsocket_write will
  95          * add any necessary version-specific stuff.  If the write fails,
  96          * no worries we are closing anyway.  If we didn't initiate this
  97          * close, then our state has been changed to
  98          * WSI_STATE_RETURNED_CLOSE_ALREADY and we can skip this
  99          */
 100
 101         if (n == WSI_STATE_ESTABLISHED)
 102                 libwebsocket_write(wsi, &buf[LWS_SEND_BUFFER_PRE_PADDING], 0,
 103                                                                LWS_WRITE_CLOSE);
 104
 105         wsi->state = WSI_STATE_DEAD_SOCKET;
 106
 107         if (wsi->protocol->callback && n == WSI_STATE_ESTABLISHED)
 108                 wsi->protocol->callback(wsi, LWS_CALLBACK_CLOSED,
 109                                                       wsi->user_space, NULL, 0);
 110
 111         for (n = 0; n < WSI_TOKEN_COUNT; n++)
 112                 if (wsi->utf8_token[n].token)
 113                         free(wsi->utf8_token[n].token);
 114
 115 /*      fprintf(stderr, "closing fd=%d\n", wsi->sock); */
 116
 117 #ifdef LWS_OPENSSL_SUPPORT
 118         if (wsi->ssl) {
 119                 n = SSL_get_fd(wsi->ssl);
 120                 SSL_shutdown(wsi->ssl);
 121                 close(n);
 122                 SSL_free(wsi->ssl);
 123         } else {
 124 #endif
 125                 shutdown(wsi->sock, SHUT_RDWR);
 126                 close(wsi->sock);
 127 #ifdef LWS_OPENSSL_SUPPORT
 128         }
 129 #endif
 130         if (wsi->user_space)
 131                 free(wsi->user_space);
 132
 133         free(wsi);
 134 }
 135
 136 /**
 137  * libwebsockets_hangup_on_client() - Server calls to terminate client
 138  *                                      connection
 139  * @this:       libwebsockets context
 140  * @fd:         Connection socket descriptor
 141  */
 142
 143 void
 144 libwebsockets_hangup_on_client(struct libwebsocket_context *this, int fd)
 145 {
 146         struct libwebsocket *wsi = wsi_from_fd(this, fd);
 147         int n;
 148
 149         if (wsi == NULL)
 150                 return;
 151
 152         delete_from_fd(this, fd);
 153
 154         for (n = 0; n < this->fds_count - 1; n++)
 155                 if (this->fds[n].fd == fd) {
 156                         while (n < this->fds_count - 1) {
 157                                 this->fds[n] = this->fds[n + 1];
 158                                 n++;
 159                         }
 160                         n = this->fds_count;
 161                         this->fds_count--;
 162                 }
 163
 164         libwebsocket_close_and_free_session(wsi);
 165 }
 166
 167
 168 /**
 169  * libwebsockets_get_peer_addresses() - Get client address information
 170  * @fd:         Connection socket descriptor
 171  * @name:       Buffer to take client address name
 172  * @name_len:   Length of client address name buffer
 173  * @rip:        Buffer to take client address IP qotted quad
 174  * @rip_len:    Length of client address IP buffer
 175  *
 176  *      This function fills in @name and @rip with the name and IP of
 177  *      the client connected with socket descriptor @fd.  Names may be
 178  *      truncated if there is not enough room.  If either cannot be
 179  *      determined, they will be returned as valid zero-length strings.
 180  */
 181
 182 void
 183 libwebsockets_get_peer_addresses(int fd, char *name, int name_len,
 184                                         char *rip, int rip_len)
 185 {
 186         unsigned int len;
 187         struct sockaddr_in sin;
 188         struct hostent *host;
 189         struct hostent *host1;
 190         char ip[128];
 191         char *p;
 192         int n;
 193
 194         rip[0] = '\0';
 195         name[0] = '\0';
 196
 197         len = sizeof sin;
 198         if (getpeername(fd, (struct sockaddr *) &sin, &len) < 0) {
 199                 perror("getpeername");
 200                 return;
 201         }
 202
 203         host = gethostbyaddr((char *) &sin.sin_addr, sizeof sin.sin_addr,
 204                                                                        AF_INET);
 205         if (host == NULL) {
 206                 perror("gethostbyaddr");
 207                 return;
 208         }
 209
 210         strncpy(name, host->h_name, name_len);
 211         name[name_len - 1] = '\0';
 212
 213         host1 = gethostbyname(host->h_name);
 214         if (host1 == NULL)
 215                 return;
 216         p = (char *)host1;
 217         n = 0;
 218         while (p != NULL) {
 219                 p = host1->h_addr_list[n++];
 220                 if (p == NULL)
 221                         continue;
 222                 if (host1->h_addrtype != AF_INET)
 223                         continue;
 224
 225                 sprintf(ip, "%d.%d.%d.%d",
 226                                 p[0], p[1], p[2], p[3]);
 227                 p = NULL;
 228                 strncpy(rip, ip, rip_len);
 229                 rip[rip_len - 1] = '\0';
 230         }
 231 }
 232
 233 /**
 234  * libwebsocket_service_fd() - Service polled socket with something waiting
 235  * @this:       Websocket context
 236  * @pollfd:     The pollfd entry describing the socket fd and which events
 237  *              happened.
 238  *
 239  *      This function closes any active connections and then frees the
 240  *      context.  After calling this, any further use of the context is
 241  *      undefined.
 242  */
 243
 244 int
 245 libwebsocket_service_fd(struct libwebsocket_context *this,
 246                                                           struct pollfd *pollfd)
 247 {
 248         unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + MAX_BROADCAST_PAYLOAD +
 249                                                   LWS_SEND_BUFFER_POST_PADDING];
 250         struct libwebsocket *wsi = wsi_from_fd(this, pollfd->fd);
 251         struct libwebsocket *new_wsi;
 252         int n;
 253         int m;
 254         size_t len;
 255         int accept_fd;
 256         unsigned int clilen;
 257         struct sockaddr_in cli_addr;
 258
 259         if (wsi == NULL)
 260                 return 1;
 261
 262         switch (wsi->mode) {
 263         case LWS_CONNMODE_SERVER_LISTENER:
 264
 265                 /* pollin means a client has connected to us then */
 266
 267                 if (!pollfd->revents & POLLIN)
 268                         break;
 269
 270                 /* listen socket got an unencrypted connection... */
 271
 272                 clilen = sizeof(cli_addr);
 273                 accept_fd  = accept(pollfd->fd, (struct sockaddr *)&cli_addr,
 274                                                                        &clilen);
 275                 if (accept_fd < 0) {
 276                         fprintf(stderr, "ERROR on accept");
 277                         break;
 278                 }
 279
 280                 if (this->fds_count >= MAX_CLIENTS) {
 281                         fprintf(stderr, "too busy to accept new client\n");
 282                         close(accept_fd);
 283                         break;
 284                 }
 285
 286                 /*
 287                  * look at who we connected to and give user code a chance
 288                  * to reject based on client IP.  There's no protocol selected
 289                  * yet so we issue this to protocols[0]
 290                  */
 291
 292                 if ((this->protocols[0].callback)(wsi,
 293                                 LWS_CALLBACK_FILTER_NETWORK_CONNECTION,
 294                                              (void*)(long)accept_fd, NULL, 0)) {
 295                         fprintf(stderr, "Callback denied network connection\n");
 296                         close(accept_fd);
 297                         break;
 298                 }
 299
 300                 /* accepting connection to main listener */
 301
 302                 new_wsi = malloc(sizeof(struct libwebsocket));
 303                 if (new_wsi == NULL) {
 304                         fprintf(stderr, "Out of memory for new connection\n");
 305                         break;
 306                 }
 307
 308                 memset(new_wsi, 0, sizeof (struct libwebsocket));
 309                 new_wsi->sock = accept_fd;
 310
 311 #ifdef LWS_OPENSSL_SUPPORT
 312                 new_wsi->ssl = NULL;
 313                 this->ssl_ctx = NULL;
 314
 315                 if (this->use_ssl) {
 316
 317                         new_wsi->ssl = SSL_new(this->ssl_ctx);
 318                         if (new_wsi->ssl == NULL) {
 319                                 fprintf(stderr, "SSL_new failed: %s\n",
 320                                     ERR_error_string(SSL_get_error(
 321                                     new_wsi->ssl, 0), NULL));
 322                                 free(new_wsi);
 323                                 break;
 324                         }
 325
 326                         SSL_set_fd(new_wsi->ssl, accept_fd);
 327
 328                         n = SSL_accept(new_wsi->ssl);
 329                         if (n != 1) {
 330                                 /*
 331                                  * browsers seem to probe with various
 332                                  * ssl params which fail then retry
 333                                  * and succeed
 334                                  */
 335                                 debug("SSL_accept failed skt %u: %s\n",
 336                                       pollfd->fd,
 337                                       ERR_error_string(SSL_get_error(
 338                                       new_wsi->ssl, n), NULL));
 339                                 SSL_free(
 340                                        new_wsi->ssl);
 341                                 free(new_wsi);
 342                                 break;
 343                         }
 344                         debug("accepted new SSL conn  "
 345                               "port %u on fd=%d SSL ver %s\n",
 346                                 ntohs(cli_addr.sin_port), accept_fd,
 347                                   SSL_get_version(new_wsi->ssl));
 348
 349                 } else
 350 #endif
 351                         debug("accepted new conn  port %u on fd=%d\n",
 352                                           ntohs(cli_addr.sin_port), accept_fd);
 353
 354                 /* intialize the instance struct */
 355
 356                 new_wsi->state = WSI_STATE_HTTP;
 357                 new_wsi->name_buffer_pos = 0;
 358                 new_wsi->mode = LWS_CONNMODE_WS_SERVING;
 359
 360                 for (n = 0; n < WSI_TOKEN_COUNT; n++) {
 361                         new_wsi->utf8_token[n].token = NULL;
 362                         new_wsi->utf8_token[n].token_len = 0;
 363                 }
 364
 365                 /*
 366                  * these can only be set once the protocol is known
 367                  * we set an unestablished connection's protocol pointer
 368                  * to the start of the supported list, so it can look
 369                  * for matching ones during the handshake
 370                  */
 371                 new_wsi->protocol = this->protocols;
 372                 new_wsi->user_space = NULL;
 373
 374                 /*
 375                  * Default protocol is 76 / 00
 376                  * After 76, there's a header specified to inform which
 377                  * draft the client wants, when that's seen we modify
 378                  * the individual connection's spec revision accordingly
 379                  */
 380                 new_wsi->ietf_spec_revision = 0;
 381
 382                 insert_wsi(this, new_wsi);
 383
 384                 /*
 385                  * make sure NO events are seen yet on this new socket
 386                  * (otherwise we inherit old fds[client].revents from
 387                  * previous socket there and die mysteriously! )
 388                  */
 389                 this->fds[this->fds_count].revents = 0;
 390
 391                 this->fds[this->fds_count].events = POLLIN;
 392                 this->fds[this->fds_count++].fd = accept_fd;
 393
 394                 /* external POLL support via protocol 0 */
 395                 this->protocols[0].callback(new_wsi,
 396                         LWS_CALLBACK_ADD_POLL_FD,
 397                         (void *)(long)accept_fd, NULL, POLLIN);
 398
 399                 break;
 400
 401         case LWS_CONNMODE_BROADCAST_PROXY_LISTENER:
 402
 403                 /* as we are listening, POLLIN means accept() is needed */
 404
 405                 if (!pollfd->revents & POLLIN)
 406                         break;
 407
 408                 /* listen socket got an unencrypted connection... */
 409
 410                 clilen = sizeof(cli_addr);
 411                 accept_fd  = accept(pollfd->fd, (struct sockaddr *)&cli_addr,
 412                                                                        &clilen);
 413                 if (accept_fd < 0) {
 414                         fprintf(stderr, "ERROR on accept");
 415                         break;
 416                 }
 417
 418                 if (this->fds_count >= MAX_CLIENTS) {
 419                         fprintf(stderr, "too busy to accept new broadcast "
 420                                                               "proxy client\n");
 421                         close(accept_fd);
 422                         break;
 423                 }
 424
 425                 /* create a dummy wsi for the connection and add it */
 426
 427                 new_wsi = malloc(sizeof(struct libwebsocket));
 428                 memset(new_wsi, 0, sizeof (struct libwebsocket));
 429                 new_wsi->sock = accept_fd;
 430                 new_wsi->mode = LWS_CONNMODE_BROADCAST_PROXY;
 431                 new_wsi->state = WSI_STATE_ESTABLISHED;
 432                 /* note which protocol we are proxying */
 433                 new_wsi->protocol_index_for_broadcast_proxy =
 434                                         wsi->protocol_index_for_broadcast_proxy;
 435                 insert_wsi(this, new_wsi);
 436
 437                 /* add connected socket to internal poll array */
 438
 439                 this->fds[this->fds_count].revents = 0;
 440                 this->fds[this->fds_count].events = POLLIN;
 441                 this->fds[this->fds_count++].fd = accept_fd;
 442
 443                 /* external POLL support via protocol 0 */
 444                 this->protocols[0].callback(new_wsi,
 445                         LWS_CALLBACK_ADD_POLL_FD,
 446                         (void *)(long)accept_fd, NULL, POLLIN);
 447
 448                 break;
 449
 450         case LWS_CONNMODE_BROADCAST_PROXY:
 451
 452                 /* handle session socket closed */
 453
 454                 if (pollfd->revents & (POLLERR | POLLHUP)) {
 455
 456                         debug("Session Socket %p (fd=%d) dead\n",
 457                                 (void *)wsi, accept_fd);
 458
 459                         libwebsocket_close_and_free_session(wsi);
 460                         goto nuke_this;
 461                 }
 462
 463                 /* the guy requested a callback when it was OK to write */
 464
 465                 if (pollfd->revents & POLLOUT) {
 466
 467                         /* one shot */
 468
 469                         pollfd->events &= ~POLLOUT;
 470
 471                         /* external POLL support via protocol 0 */
 472                         this->protocols[0].callback(wsi,
 473                                 LWS_CALLBACK_CLEAR_MODE_POLL_FD,
 474                                 (void *)(long)wsi->sock, NULL, POLLOUT);
 475
 476                         wsi->protocol->callback(wsi,
 477                                 LWS_CALLBACK_CLIENT_WRITEABLE,
 478                                 wsi->user_space,
 479                                 NULL, 0);
 480                 }
 481
 482                 /* any incoming data ready? */
 483
 484                 if (!(pollfd->revents & POLLIN))
 485                         break;
 486
 487                 /* get the issued broadcast payload from the socket */
 488
 489                 len = read(pollfd->fd, buf + LWS_SEND_BUFFER_PRE_PADDING,
 490                                                          MAX_BROADCAST_PAYLOAD);
 491                 if (len < 0) {
 492                         fprintf(stderr, "Error reading broadcast payload\n");
 493                         break;;
 494                 }
 495
 496                 /* broadcast it to all guys with this protocol index */
 497
 498                 for (n = 0; n < FD_HASHTABLE_MODULUS; n++) {
 499
 500                         for (m = 0; m < this->fd_hashtable[n].length; m++) {
 501
 502                                 new_wsi = this->fd_hashtable[n].wsi[m];
 503
 504                                 /* only to clients we are serving to */
 505
 506                                 if (new_wsi->mode != LWS_CONNMODE_WS_SERVING)
 507                                         continue;
 508
 509                                 /*
 510                                  * never broadcast to non-established
 511                                  * connection
 512                                  */
 513
 514                                 if (new_wsi->state != WSI_STATE_ESTABLISHED)
 515                                         continue;
 516
 517                                 /*
 518                                  * only broadcast to connections using
 519                                  * the requested protocol
 520                                  */
 521
 522                                 if (new_wsi->protocol->protocol_index !=
 523                                         wsi->protocol_index_for_broadcast_proxy)
 524                                         continue;
 525
 526                                 /* broadcast it to this connection */
 527
 528                                 new_wsi->protocol->callback(new_wsi,
 529                                         LWS_CALLBACK_BROADCAST,
 530                                         new_wsi->user_space,
 531                                         buf + LWS_SEND_BUFFER_PRE_PADDING, len);
 532                         }
 533                 }
 534                 break;
 535
 536         case LWS_CONNMODE_WS_SERVING:
 537         case LWS_CONNMODE_WS_CLIENT:
 538
 539                 /* handle session socket closed */
 540
 541                 if (pollfd->revents & (POLLERR | POLLHUP)) {
 542
 543                         debug("Session Socket %p (fd=%d) dead\n",
 544                                 (void *)wsi, pollfd->fd);
 545
 546                         libwebsocket_close_and_free_session(wsi);
 547                         goto nuke_this;
 548                 }
 549
 550                 /* the guy requested a callback when it was OK to write */
 551
 552                 if (pollfd->revents & POLLOUT) {
 553
 554                         pollfd->events &= ~POLLOUT;
 555
 556                         /* external POLL support via protocol 0 */
 557                         this->protocols[0].callback(wsi,
 558                                 LWS_CALLBACK_CLEAR_MODE_POLL_FD,
 559                                 (void *)(long)wsi->sock, NULL, POLLOUT);
 560
 561                         wsi->protocol->callback(wsi,
 562                                 LWS_CALLBACK_CLIENT_WRITEABLE,
 563                                 wsi->user_space,
 564                                 NULL, 0);
 565                 }
 566
 567                 /* any incoming data ready? */
 568
 569                 if (!(pollfd->revents & POLLIN))
 570                         break;
 571
 572 #ifdef LWS_OPENSSL_SUPPORT
 573                 if (wsi->ssl)
 574                         n = SSL_read(wsi->ssl, buf, sizeof buf);
 575                 else
 576 #endif
 577                         n = recv(pollfd->fd, buf, sizeof buf, 0);
 578
 579                 if (n < 0) {
 580                         fprintf(stderr, "Socket read returned %d\n", n);
 581                         break;;
 582                 }
 583                 if (!n) {
 584                         libwebsocket_close_and_free_session(wsi);
 585                         goto nuke_this;
 586                 }
 587
 588                 /* service incoming data */
 589
 590                 n = libwebsocket_read(wsi, buf, n);
 591                 if (n >= 0)
 592                         break;;
 593                 /*
 594                  * it closed and nuked wsi[client], so remove the
 595                  * socket handle and wsi from our service list
 596                  */
 597 nuke_this:
 598
 599                 debug("nuking wsi %p, fsd_count = %d\n",
 600                                 (void *)wsi, this->fds_count - 1);
 601
 602                 delete_from_fd(this, pollfd->fd);
 603
 604                 this->fds_count--;
 605                 for (n = 0; n < this->fds_count; n++)
 606                         if (this->fds[n].fd == pollfd->fd) {
 607                                 while (n < this->fds_count) {
 608                                         this->fds[n] = this->fds[n + 1];
 609                                         n++;
 610                                 }
 611                                 n = this->fds_count;
 612                         }
 613
 614                 /* external POLL support via protocol 0 */
 615                 this->protocols[0].callback(wsi,
 616                         LWS_CALLBACK_DEL_POLL_FD,
 617                         (void *)(long)pollfd->fd, NULL, 0);
 618
 619
 620                 break;
 621         }
 622
 623         return 0;
 624 }
 625
 626
 627 /**
 628  * libwebsocket_context_destroy() - Destroy the websocket context
 629  * @this:       Websocket context
 630  *
 631  *      This function closes any active connections and then frees the
 632  *      context.  After calling this, any further use of the context is
 633  *      undefined.
 634  */
 635 void
 636 libwebsocket_context_destroy(struct libwebsocket_context *this)
 637 {
 638         int n;
 639         int m;
 640         struct libwebsocket *wsi;
 641
 642         for (n = 0; n < FD_HASHTABLE_MODULUS; n++) {
 643
 644                 for (m = 0; m < this->fd_hashtable[n].length; m++) {
 645
 646                         wsi = this->fd_hashtable[n].wsi[m];
 647
 648                         switch (wsi->mode) {
 649                         case LWS_CONNMODE_WS_SERVING:
 650                                 libwebsocket_close_and_free_session(wsi);
 651                                 break;
 652                         case LWS_CONNMODE_WS_CLIENT:
 653                                 libwebsocket_client_close(wsi);
 654                                 break;
 655                         default:
 656                                 break;
 657                         }
 658                 }
 659         }
 660
 661         close(this->fd_random);
 662
 663 #ifdef LWS_OPENSSL_SUPPORT
 664         if (this->ssl_ctx)
 665                 SSL_CTX_free(this->ssl_ctx);
 666         if (this->ssl_client_ctx)
 667                 SSL_CTX_free(this->ssl_client_ctx);
 668 #endif
 669
 670         free(this);
 671 }
 672
 673 /**
 674  * libwebsocket_service() - Service any pending websocket activity
 675  * @this:       Websocket context
 676  * @timeout_ms: Timeout for poll; 0 means return immediately if nothing needed
 677  *              service otherwise block and service immediately, returning
 678  *              after the timeout if nothing needed service.
 679  *
 680  *      This function deals with any pending websocket traffic, for three
 681  *      kinds of event.  It handles these events on both server and client
 682  *      types of connection the same.
 683  *
 684  *      1) Accept new connections to our context's server
 685  *
 686  *      2) Perform pending broadcast writes initiated from other forked
 687  *         processes (effectively serializing asynchronous broadcasts)
 688  *
 689  *      3) Call the receive callback for incoming frame data received by
 690  *          server or client connections.
 691  *
 692  *      You need to call this service function periodically to all the above
 693  *      functions to happen; if your application is single-threaded you can
 694  *      just call it in your main event loop.
 695  *
 696  *      Alternatively you can fork a new process that asynchronously handles
 697  *      calling this service in a loop.  In that case you are happy if this
 698  *      call blocks your thread until it needs to take care of something and
 699  *      would call it with a large nonzero timeout.  Your loop then takes no
 700  *      CPU while there is nothing happening.
 701  *
 702  *      If you are calling it in a single-threaded app, you don't want it to
 703  *      wait around blocking other things in your loop from happening, so you
 704  *      would call it with a timeout_ms of 0, so it returns immediately if
 705  *      nothing is pending, or as soon as it services whatever was pending.
 706  */
 707
 708
 709 int
 710 libwebsocket_service(struct libwebsocket_context *this, int timeout_ms)
 711 {
 712         int n;
 713
 714         /* stay dead once we are dead */
 715
 716         if (this == NULL)
 717                 return 1;
 718
 719         /* wait for something to need service */
 720
 721         n = poll(this->fds, this->fds_count, timeout_ms);
 722         if (n == 0) /* poll timeout */
 723                 return 0;
 724
 725         if (n < 0 || this->fds[0].revents & (POLLERR | POLLHUP)) {
 726                 /*
 727                 fprintf(stderr, "Listen Socket dead\n");
 728                 */
 729                 return 1;
 730         }
 731
 732         /* handle accept on listening socket? */
 733
 734         for (n = 0; n < this->fds_count; n++)
 735                 if (this->fds[n].revents)
 736                         libwebsocket_service_fd(this, &this->fds[n]);
 737
 738         return 0;
 739 }
 740
 741 /**
 742  * libwebsocket_callback_on_writable() - Request a callback when this socket
 743  *                                       becomes able to be written to without
 744  *                                       blocking
 745  * *
 746  * @wsi:        Websocket connection instance to get callback for
 747  */
 748
 749 int
 750 libwebsocket_callback_on_writable(struct libwebsocket *wsi)
 751 {
 752         struct libwebsocket_context *this = wsi->protocol->owning_server;
 753         int n;
 754
 755         for (n = 0; n < this->fds_count; n++)
 756                 if (this->fds[n].fd == wsi->sock) {
 757                         this->fds[n].events |= POLLOUT;
 758                         n = this->fds_count;
 759                 }
 760
 761         /* external POLL support via protocol 0 */
 762         this->protocols[0].callback(wsi,
 763                 LWS_CALLBACK_SET_MODE_POLL_FD,
 764                 (void *)(long)wsi->sock, NULL, POLLOUT);
 765
 766         return 1;
 767 }
 768
 769 /**
 770  * libwebsocket_callback_on_writable_all_protocol() - Request a callback for
 771  *                      all connections using the given protocol when it
 772  *                      becomes possible to write to each socket without
 773  *                      blocking in turn.
 774  *
 775  * @protocol:   Protocol whose connections will get callbacks
 776  */
 777
 778 int
 779 libwebsocket_callback_on_writable_all_protocol(
 780                                   const struct libwebsocket_protocols *protocol)
 781 {
 782         struct libwebsocket_context *this = protocol->owning_server;
 783         int n;
 784         int m;
 785         struct libwebsocket *wsi;
 786
 787         for (n = 0; n < FD_HASHTABLE_MODULUS; n++) {
 788
 789                 for (m = 0; m < this->fd_hashtable[n].length; m++) {
 790
 791                         wsi = this->fd_hashtable[n].wsi[m];
 792
 793                         if (wsi->protocol == protocol)
 794                                 libwebsocket_callback_on_writable(wsi);
 795                 }
 796         }
 797
 798         return 0;
 799 }
 800
 801
 802 /**
 803  * libwebsocket_get_socket_fd() - returns the socket file descriptor
 804  *
 805  * You will not need this unless you are doing something special
 806  *
 807  * @wsi:        Websocket connection instance
 808  */
 809
 810 int
 811 libwebsocket_get_socket_fd(struct libwebsocket *wsi)
 812 {
 813         return wsi->sock;
 814 }
 815
 816 /**
 817  * libwebsocket_rx_flow_control() - Enable and disable socket servicing for
 818  *                              receieved packets.
 819  *
 820  * If the output side of a server process becomes choked, this allows flow
 821  * control for the input side.
 822  *
 823  * @wsi:        Websocket connection instance to get callback for
 824  * @enable:     0 = disable read servicing for this connection, 1 = enable
 825  */
 826
 827 int
 828 libwebsocket_rx_flow_control(struct libwebsocket *wsi, int enable)
 829 {
 830         struct libwebsocket_context *this = wsi->protocol->owning_server;
 831         int n;
 832
 833         for (n = 0; n < this->fds_count; n++)
 834                 if (this->fds[n].fd == wsi->sock) {
 835                         if (enable)
 836                                 this->fds[n].events |= POLLIN;
 837                         else
 838                                 this->fds[n].events &= ~POLLIN;
 839
 840                         return 0;
 841                 }
 842
 843         if (enable)
 844                 /* external POLL support via protocol 0 */
 845                 this->protocols[0].callback(wsi,
 846                         LWS_CALLBACK_SET_MODE_POLL_FD,
 847                         (void *)(long)wsi->sock, NULL, POLLIN);
 848         else
 849                 /* external POLL support via protocol 0 */
 850                 this->protocols[0].callback(wsi,
 851                         LWS_CALLBACK_CLEAR_MODE_POLL_FD,
 852                         (void *)(long)wsi->sock, NULL, POLLIN);
 853
 854
 855         fprintf(stderr, "libwebsocket_callback_on_writable "
 856                                                      "unable to find socket\n");
 857         return 1;
 858 }
 859
 860 /**
 861  * libwebsocket_canonical_hostname() - returns this host's hostname
 862  *
 863  * This is typically used by client code to fill in the host parameter
 864  * when making a client connection.  You can only call it after the context
 865  * has been created.
 866  *
 867  * @this:       Websocket context
 868  */
 869
 870
 871 extern const char *
 872 libwebsocket_canonical_hostname(struct libwebsocket_context *this)
 873 {
 874         return (const char *)this->canonical_hostname;
 875 }
 876
 877
 878 static void sigpipe_handler(int x)
 879 {
 880 }
 881
 882
 883
 884 /**
 885  * libwebsocket_create_context() - Create the websocket handler
 886  * @port:       Port to listen on... you can use 0 to suppress listening on
 887  *              any port, that's what you want if you are not running a
 888  *              websocket server at all but just using it as a client
 889  * @protocols:  Array of structures listing supported protocols and a protocol-
 890  *              specific callback for each one.  The list is ended with an
 891  *              entry that has a NULL callback pointer.
 892  *              It's not const because we write the owning_server member
 893  * @ssl_cert_filepath:  If libwebsockets was compiled to use ssl, and you want
 894  *                      to listen using SSL, set to the filepath to fetch the
 895  *                      server cert from, otherwise NULL for unencrypted
 896  * @ssl_private_key_filepath: filepath to private key if wanting SSL mode,
 897  *                      else ignored
 898  * @gid:        group id to change to after setting listen socket, or -1.
 899  * @uid:        user id to change to after setting listen socket, or -1.
 900  * @options:    0, or LWS_SERVER_OPTION_DEFEAT_CLIENT_MASK
 901  *
 902  *      This function creates the listening socket and takes care
 903  *      of all initialization in one step.
 904  *
 905  *      After initialization, it returns a struct libwebsocket_context * that
 906  *      represents this server.  After calling, user code needs to take care
 907  *      of calling libwebsocket_service() with the context pointer to get the
 908  *      server's sockets serviced.  This can be done in the same process context
 909  *      or a forked process, or another thread,
 910  *
 911  *      The protocol callback functions are called for a handful of events
 912  *      including http requests coming in, websocket connections becoming
 913  *      established, and data arriving; it's also called periodically to allow
 914  *      async transmission.
 915  *
 916  *      HTTP requests are sent always to the FIRST protocol in @protocol, since
 917  *      at that time websocket protocol has not been negotiated.  Other
 918  *      protocols after the first one never see any HTTP callack activity.
 919  *
 920  *      The server created is a simple http server by default; part of the
 921  *      websocket standard is upgrading this http connection to a websocket one.
 922  *
 923  *      This allows the same server to provide files like scripts and favicon /
 924  *      images or whatever over http and dynamic data over websockets all in
 925  *      one place; they're all handled in the user callback.
 926  */
 927
 928 struct libwebsocket_context *
 929 libwebsocket_create_context(int port,
 930                                struct libwebsocket_protocols *protocols,
 931                                const char *ssl_cert_filepath,
 932                                const char *ssl_private_key_filepath,
 933                                int gid, int uid, unsigned int options)
 934 {
 935         int n;
 936         int sockfd = 0;
 937         int fd;
 938         struct sockaddr_in serv_addr, cli_addr;
 939         int opt = 1;
 940         struct libwebsocket_context *this = NULL;
 941         unsigned int slen;
 942         char *p;
 943         char hostname[1024];
 944         struct hostent *he;
 945         struct libwebsocket *wsi;
 946
 947 #ifdef LWS_OPENSSL_SUPPORT
 948         SSL_METHOD *method;
 949         char ssl_err_buf[512];
 950 #endif
 951
 952         this = malloc(sizeof(struct libwebsocket_context));
 953         if (!this) {
 954                 fprintf(stderr, "No memory for websocket context\n");
 955                 return NULL;
 956         }
 957         this->protocols = protocols;
 958         this->listen_port = port;
 959         this->http_proxy_port = 0;
 960         this->http_proxy_address[0] = '\0';
 961         this->options = options;
 962         this->fds_count = 0;
 963
 964         this->fd_random = open(SYSTEM_RANDOM_FILEPATH, O_RDONLY);
 965         if (this->fd_random < 0) {
 966                 fprintf(stderr, "Unable to open random device %s %d\n",
 967                                        SYSTEM_RANDOM_FILEPATH, this->fd_random);
 968                 return NULL;
 969         }
 970
 971         /* find canonical hostname */
 972
 973         hostname[(sizeof hostname) - 1] = '\0';
 974         gethostname(hostname, (sizeof hostname) - 1);
 975         he = gethostbyname(hostname);
 976         strncpy(this->canonical_hostname, he->h_name,
 977                                            sizeof this->canonical_hostname - 1);
 978         this->canonical_hostname[sizeof this->canonical_hostname - 1] = '\0';
 979
 980         /* split the proxy ads:port if given */
 981
 982         p = getenv("http_proxy");
 983         if (p) {
 984                 strncpy(this->http_proxy_address, p,
 985                                            sizeof this->http_proxy_address - 1);
 986                 this->http_proxy_address[
 987                                     sizeof this->http_proxy_address - 1] = '\0';
 988
 989                 p = strchr(this->http_proxy_address, ':');
 990                 if (p == NULL) {
 991                         fprintf(stderr, "http_proxy needs to be ads:port\n");
 992                         return NULL;
 993                 }
 994                 *p = '\0';
 995                 this->http_proxy_port = atoi(p + 1);
 996
 997                 fprintf(stderr, "Using proxy %s:%u\n",
 998                                 this->http_proxy_address,
 999                                                         this->http_proxy_port);
1000         }
1001
1002         if (port) {
1003
1004 #ifdef LWS_OPENSSL_SUPPORT
1005                 this->use_ssl = ssl_cert_filepath != NULL &&
1006                                                ssl_private_key_filepath != NULL;
1007                 if (this->use_ssl)
1008                         fprintf(stderr, " Compiled with SSL support, "
1009                                                                   "using it\n");
1010                 else
1011                         fprintf(stderr, " Compiled with SSL support, "
1012                                                               "not using it\n");
1013
1014 #else
1015                 if (ssl_cert_filepath != NULL &&
1016                                              ssl_private_key_filepath != NULL) {
1017                         fprintf(stderr, " Not compiled for OpenSSl support!\n");
1018                         return NULL;
1019                 }
1020                 fprintf(stderr, " Compiled without SSL support, "
1021                                                        "serving unencrypted\n");
1022 #endif
1023         }
1024
1025         /* ignore SIGPIPE */
1026
1027         signal(SIGPIPE, sigpipe_handler);
1028
1029
1030 #ifdef LWS_OPENSSL_SUPPORT
1031
1032         /* basic openssl init */
1033
1034         SSL_library_init();
1035
1036         OpenSSL_add_all_algorithms();
1037         SSL_load_error_strings();
1038
1039         /*
1040          * Firefox insists on SSLv23 not SSLv3
1041          * Konq disables SSLv2 by default now, SSLv23 works
1042          */
1043
1044         method = (SSL_METHOD *)SSLv23_server_method();
1045         if (!method) {
1046                 fprintf(stderr, "problem creating ssl method: %s\n",
1047                         ERR_error_string(ERR_get_error(), ssl_err_buf));
1048                 return NULL;
1049         }
1050         this->ssl_ctx = SSL_CTX_new(method);    /* create context */
1051         if (!this->ssl_ctx) {
1052                 fprintf(stderr, "problem creating ssl context: %s\n",
1053                         ERR_error_string(ERR_get_error(), ssl_err_buf));
1054                 return NULL;
1055         }
1056
1057         /* client context */
1058
1059         method = (SSL_METHOD *)SSLv23_client_method();
1060         if (!method) {
1061                 fprintf(stderr, "problem creating ssl method: %s\n",
1062                         ERR_error_string(ERR_get_error(), ssl_err_buf));
1063                 return NULL;
1064         }
1065         this->ssl_client_ctx = SSL_CTX_new(method);     /* create context */
1066         if (!this->ssl_client_ctx) {
1067                 fprintf(stderr, "problem creating ssl context: %s\n",
1068                         ERR_error_string(ERR_get_error(), ssl_err_buf));
1069                 return NULL;
1070         }
1071
1072
1073         /* openssl init for cert verification (used with client sockets) */
1074
1075         if (!SSL_CTX_load_verify_locations(this->ssl_client_ctx, NULL,
1076                                                     LWS_OPENSSL_CLIENT_CERTS)) {
1077                 fprintf(stderr, "Unable to load SSL Client certs from %s "
1078                         "(set by --with-client-cert-dir= in configure) -- "
1079                         " client ssl isn't going to work",
1080                                                       LWS_OPENSSL_CLIENT_CERTS);
1081         }
1082
1083         if (this->use_ssl) {
1084
1085                 /* openssl init for server sockets */
1086
1087                 /* set the local certificate from CertFile */
1088                 n = SSL_CTX_use_certificate_file(this->ssl_ctx,
1089                                         ssl_cert_filepath, SSL_FILETYPE_PEM);
1090                 if (n != 1) {
1091                         fprintf(stderr, "problem getting cert '%s': %s\n",
1092                                 ssl_cert_filepath,
1093                                 ERR_error_string(ERR_get_error(), ssl_err_buf));
1094                         return NULL;
1095                 }
1096                 /* set the private key from KeyFile */
1097                 if (SSL_CTX_use_PrivateKey_file(this->ssl_ctx,
1098                                                 ssl_private_key_filepath,
1099                                                        SSL_FILETYPE_PEM) != 1) {
1100                         fprintf(stderr, "ssl problem getting key '%s': %s\n",
1101                                                 ssl_private_key_filepath,
1102                                 ERR_error_string(ERR_get_error(), ssl_err_buf));
1103                         return NULL;
1104                 }
1105                 /* verify private key */
1106                 if (!SSL_CTX_check_private_key(this->ssl_ctx)) {
1107                         fprintf(stderr, "Private SSL key doesn't match cert\n");
1108                         return NULL;
1109                 }
1110
1111                 /* SSL is happy and has a cert it's content with */
1112         }
1113 #endif
1114
1115         /* selftest */
1116
1117         if (lws_b64_selftest())
1118                 return NULL;
1119
1120         /* fd hashtable init */
1121
1122         for (n = 0; n < FD_HASHTABLE_MODULUS; n++)
1123                 this->fd_hashtable[n].length = 0;
1124
1125         /* set up our external listening socket we serve on */
1126
1127         if (port) {
1128
1129                 sockfd = socket(AF_INET, SOCK_STREAM, 0);
1130                 if (sockfd < 0) {
1131                         fprintf(stderr, "ERROR opening socket");
1132                         return NULL;
1133                 }
1134
1135                 /* allow us to restart even if old sockets in TIME_WAIT */
1136                 setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
1137
1138                 bzero((char *) &serv_addr, sizeof(serv_addr));
1139                 serv_addr.sin_family = AF_INET;
1140                 serv_addr.sin_addr.s_addr = INADDR_ANY;
1141                 serv_addr.sin_port = htons(port);
1142
1143                 n = bind(sockfd, (struct sockaddr *) &serv_addr,
1144                                                              sizeof(serv_addr));
1145                 if (n < 0) {
1146                         fprintf(stderr, "ERROR on binding to port %d (%d %d)\n",
1147                                                                 port, n, errno);
1148                         return NULL;
1149                 }
1150
1151                 wsi = malloc(sizeof(struct libwebsocket));
1152                 memset(wsi, 0, sizeof (struct libwebsocket));
1153                 wsi->sock = sockfd;
1154                 wsi->mode = LWS_CONNMODE_SERVER_LISTENER;
1155                 insert_wsi(this, wsi);
1156
1157                 listen(sockfd, 5);
1158                 fprintf(stderr, " Listening on port %d\n", port);
1159
1160                 /* list in the internal poll array */
1161
1162                 this->fds[this->fds_count].fd = sockfd;
1163                 this->fds[this->fds_count++].events = POLLIN;
1164
1165                 /* external POLL support via protocol 0 */
1166                 this->protocols[0].callback(wsi,
1167                         LWS_CALLBACK_ADD_POLL_FD,
1168                         (void *)(long)sockfd, NULL, POLLIN);
1169
1170         }
1171
1172         /* drop any root privs for this process */
1173
1174         if (gid != -1)
1175                 if (setgid(gid))
1176                         fprintf(stderr, "setgid: %s\n", strerror(errno));
1177         if (uid != -1)
1178                 if (setuid(uid))
1179                         fprintf(stderr, "setuid: %s\n", strerror(errno));
1180
1181
1182         /* set up our internal broadcast trigger sockets per-protocol */
1183
1184         for (this->count_protocols = 0;
1185                         protocols[this->count_protocols].callback;
1186                                                       this->count_protocols++) {
1187                 protocols[this->count_protocols].owning_server = this;
1188                 protocols[this->count_protocols].protocol_index =
1189                                                           this->count_protocols;
1190
1191                 fd = socket(AF_INET, SOCK_STREAM, 0);
1192                 if (fd < 0) {
1193                         fprintf(stderr, "ERROR opening socket");
1194                         return NULL;
1195                 }
1196
1197                 /* allow us to restart even if old sockets in TIME_WAIT */
1198                 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
1199
1200                 bzero((char *) &serv_addr, sizeof(serv_addr));
1201                 serv_addr.sin_family = AF_INET;
1202                 serv_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
1203                 serv_addr.sin_port = 0; /* pick the port for us */
1204
1205                 n = bind(fd, (struct sockaddr *) &serv_addr, sizeof(serv_addr));
1206                 if (n < 0) {
1207                         fprintf(stderr, "ERROR on binding to port %d (%d %d)\n",
1208                                                                 port, n, errno);
1209                         return NULL;
1210                 }
1211
1212                 slen = sizeof cli_addr;
1213                 n = getsockname(fd, (struct sockaddr *)&cli_addr, &slen);
1214                 if (n < 0) {
1215                         fprintf(stderr, "getsockname failed\n");
1216                         return NULL;
1217                 }
1218                 protocols[this->count_protocols].broadcast_socket_port =
1219                                                        ntohs(cli_addr.sin_port);
1220                 listen(fd, 5);
1221
1222                 debug("  Protocol %s broadcast socket %d\n",
1223                                 protocols[this->count_protocols].name,
1224                                                       ntohs(cli_addr.sin_port));
1225
1226                 /* dummy wsi per broadcast proxy socket */
1227
1228                 wsi = malloc(sizeof(struct libwebsocket));
1229                 memset(wsi, 0, sizeof (struct libwebsocket));
1230                 wsi->sock = fd;
1231                 wsi->mode = LWS_CONNMODE_BROADCAST_PROXY_LISTENER;
1232                 /* note which protocol we are proxying */
1233                 wsi->protocol_index_for_broadcast_proxy = this->count_protocols;
1234                 insert_wsi(this, wsi);
1235
1236                 /* list in internal poll array */
1237
1238                 this->fds[this->fds_count].fd = fd;
1239                 this->fds[this->fds_count].events = POLLIN;
1240                 this->fds[this->fds_count].revents = 0;
1241                 this->fds_count++;
1242
1243                 /* external POLL support via protocol 0 */
1244                 this->protocols[0].callback(wsi,
1245                         LWS_CALLBACK_ADD_POLL_FD,
1246                         (void *)(long)fd, NULL, POLLIN);
1247         }
1248
1249         return this;
1250 }
1251
1252
1253 #ifndef LWS_NO_FORK
1254
1255 /**
1256  * libwebsockets_fork_service_loop() - Optional helper function forks off
1257  *                                a process for the websocket server loop.
1258  *                              You don't have to use this but if not, you
1259  *                              have to make sure you are calling
1260  *                              libwebsocket_service periodically to service
1261  *                              the websocket traffic
1262  * @this:       server context returned by creation function
1263  */
1264
1265 int
1266 libwebsockets_fork_service_loop(struct libwebsocket_context *this)
1267 {
1268         int fd;
1269         struct sockaddr_in cli_addr;
1270         int n;
1271         int p;
1272
1273         n = fork();
1274         if (n < 0)
1275                 return n;
1276
1277         if (!n) {
1278
1279                 /* main process context */
1280
1281                 /*
1282                  * set up the proxy sockets to allow broadcast from
1283                  * service process context
1284                  */
1285
1286                 for (p = 0; p < this->count_protocols; p++) {
1287                         fd = socket(AF_INET, SOCK_STREAM, 0);
1288                         if (fd < 0) {
1289                                 fprintf(stderr, "Unable to create socket\n");
1290                                 return -1;
1291                         }
1292                         cli_addr.sin_family = AF_INET;
1293                         cli_addr.sin_port = htons(
1294                              this->protocols[p].broadcast_socket_port);
1295                         cli_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
1296                         n = connect(fd, (struct sockaddr *)&cli_addr,
1297                                                                sizeof cli_addr);
1298                         if (n < 0) {
1299                                 fprintf(stderr, "Unable to connect to "
1300                                                 "broadcast socket %d, %s\n",
1301                                                 n, strerror(errno));
1302                                 return -1;
1303                         }
1304
1305                         this->protocols[p].broadcast_socket_user_fd = fd;
1306                 }
1307
1308                 return 0;
1309         }
1310
1311         /* we want a SIGHUP when our parent goes down */
1312         prctl(PR_SET_PDEATHSIG, SIGHUP);
1313
1314         /* in this forked process, sit and service websocket connections */
1315
1316         while (1)
1317                 if (libwebsocket_service(this, 1000))
1318                         return -1;
1319
1320         return 0;
1321 }
1322
1323 #endif
1324
1325 /**
1326  * libwebsockets_get_protocol() - Returns a protocol pointer from a websocket
1327  *                                connection.
1328  * @wsi:        pointer to struct websocket you want to know the protocol of
1329  *
1330  *
1331  *      This is useful to get the protocol to broadcast back to from inside
1332  * the callback.
1333  */
1334
1335 const struct libwebsocket_protocols *
1336 libwebsockets_get_protocol(struct libwebsocket *wsi)
1337 {
1338         return wsi->protocol;
1339 }
1340
1341 /**
1342  * libwebsockets_broadcast() - Sends a buffer to the callback for all active
1343  *                                connections of the given protocol.
1344  * @protocol:   pointer to the protocol you will broadcast to all members of
1345  * @buf:  buffer containing the data to be broadcase.  NOTE: this has to be
1346  *              allocated with LWS_SEND_BUFFER_PRE_PADDING valid bytes before
1347  *              the pointer and LWS_SEND_BUFFER_POST_PADDING afterwards in the
1348  *              case you are calling this function from callback context.
1349  * @len:        length of payload data in buf, starting from buf.
1350  *
1351  *      This function allows bulk sending of a packet to every connection using
1352  * the given protocol.  It does not send the data directly; instead it calls
1353  * the callback with a reason type of LWS_CALLBACK_BROADCAST.  If the callback
1354  * wants to actually send the data for that connection, the callback itself
1355  * should call libwebsocket_write().
1356  *
1357  * libwebsockets_broadcast() can be called from another fork context without
1358  * having to take any care about data visibility between the processes, it'll
1359  * "just work".
1360  */
1361
1362
1363 int
1364 libwebsockets_broadcast(const struct libwebsocket_protocols *protocol,
1365                                                  unsigned char *buf, size_t len)
1366 {
1367         struct libwebsocket_context *this = protocol->owning_server;
1368         int n;
1369         int m;
1370         struct libwebsocket * wsi;
1371
1372         if (!protocol->broadcast_socket_user_fd) {
1373                 /*
1374                  * We are either running unforked / flat, or we are being
1375                  * called from poll thread context
1376                  * eg, from a callback.  In that case don't use sockets for
1377                  * broadcast IPC (since we can't open a socket connection to
1378                  * a socket listening on our own thread) but directly do the
1379                  * send action.
1380                  *
1381                  * Locking is not needed because we are by definition being
1382                  * called in the poll thread context and are serialized.
1383                  */
1384
1385                 for (n = 0; n < FD_HASHTABLE_MODULUS; n++) {
1386
1387                         for (m = 0; m < this->fd_hashtable[n].length; m++) {
1388
1389                                 wsi = this->fd_hashtable[n].wsi[m];
1390
1391                                 if (wsi->mode != LWS_CONNMODE_WS_SERVING)
1392                                         continue;
1393
1394                                 /*
1395                                  * never broadcast to
1396                                  * non-established connections
1397                                  */
1398                                 if (wsi->state != WSI_STATE_ESTABLISHED)
1399                                         continue;
1400
1401                                 /* only broadcast to guys using
1402                                  * requested protocol
1403                                  */
1404                                 if (wsi->protocol != protocol)
1405                                         continue;
1406
1407                                 wsi->protocol->callback(wsi,
1408                                          LWS_CALLBACK_BROADCAST,
1409                                          wsi->user_space,
1410                                          buf, len);
1411                         }
1412                 }
1413
1414                 return 0;
1415         }
1416
1417         /*
1418          * We're being called from a different process context than the server
1419          * loop.  Instead of broadcasting directly, we send our
1420          * payload on a socket to do the IPC; the server process will serialize
1421          * the broadcast action in its main poll() loop.
1422          *
1423          * There's one broadcast socket listening for each protocol supported
1424          * set up when the websocket server initializes
1425          */
1426
1427         n = send(protocol->broadcast_socket_user_fd, buf, len, MSG_NOSIGNAL);
1428
1429         return n;
1430 }