lib/libwebsockets.c

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