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