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