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