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