test-server/test-server.c

   1 /*
   2  * libwebsockets-test-server - libwebsockets test implementation
   3  *
   4  * Copyright (C) 2010-2011 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 <stdio.h>
  23 #include <stdlib.h>
  24 #include <unistd.h>
  25 #include <getopt.h>
  26 #include <string.h>
  27 #include <sys/time.h>
  28 #include <assert.h>
  29
  30 #include "../lib/libwebsockets.h"
  31
  32 static int close_testing;
  33
  34 #ifdef EXTERNAL_POLL
  35 #define LWS_NO_FORK
  36 #ifndef MAX_CLIENTS
  37 #define MAX_POLL_ELEMENTS 100
  38 #else
  39 #define MAX_POLL_ELEMENTS (MAX_CLIENTS)
  40 #endif
  41
  42 struct poll_hash_map {
  43         int fd;
  44         int index;
  45 };
  46
  47 #define POLL_HASH_BITS 8
  48
  49 #define POLL_HASH_BUCKETS (1 << POLL_HASH_BITS)
  50 #define POLL_ENTRIES_PER_BUCKET (MAX_POLL_ELEMENTS / (1 << (POLL_HASH_BITS - 2)))
  51 #define POLL_HASH(num) (num & (POLL_HASH_BUCKETS - 1))
  52
  53 struct pollfd pollfds[MAX_POLL_ELEMENTS];
  54 struct poll_hash_map pollfd_maps[POLL_HASH_BUCKETS][POLL_ENTRIES_PER_BUCKET];
  55 int pollfd_count[POLL_HASH_BUCKETS];
  56 int count_pollfds = 0;
  57
  58 static int find_poll_map_index(int hash, int fd)
  59 {
  60         int n;
  61
  62         for (n = 0; n < pollfd_count[hash]; n++)
  63                 if (pollfd_maps[hash][n].fd == fd)
  64                         return n;
  65
  66         return -1;
  67 }
  68
  69 static int find_pollfd_index(int fd)
  70 {
  71         int n;
  72         int hash = POLL_HASH(fd);
  73
  74         n = find_poll_map_index(hash, fd);
  75         if (n < 0)
  76                 return n;
  77
  78         return pollfd_maps[hash][n].index;
  79 }
  80
  81 #endif /* EXTERNAL_POLL */
  82
  83 /*
  84  * This demo server shows how to use libwebsockets for one or more
  85  * websocket protocols in the same server
  86  *
  87  * It defines the following websocket protocols:
  88  *
  89  *  dumb-increment-protocol:  once the socket is opened, an incrementing
  90  *                              ascii string is sent down it every 50ms.
  91  *                              If you send "reset\n" on the websocket, then
  92  *                              the incrementing number is reset to 0.
  93  *
  94  *  lws-mirror-protocol: copies any received packet to every connection also
  95  *                              using this protocol, including the sender
  96  */
  97
  98 enum demo_protocols {
  99         /* always first */
 100         PROTOCOL_HTTP = 0,
 101
 102         PROTOCOL_DUMB_INCREMENT,
 103         PROTOCOL_LWS_MIRROR,
 104
 105         /* always last */
 106         DEMO_PROTOCOL_COUNT
 107 };
 108
 109
 110 #define LOCAL_RESOURCE_PATH INSTALL_DATADIR"/libwebsockets-test-server"
 111
 112 /*
 113  * We take a strict whitelist approach to stop ../ attacks
 114  */
 115
 116 struct serveable {
 117         const char *urlpath;
 118         const char *mimetype;
 119 };
 120
 121 static const struct serveable whitelist[] = {
 122         { "/favicon.ico", "image/x-icon" },
 123         { "/libwebsockets.org-logo.png", "image/png" },
 124
 125         /* last one is the default served if no match */
 126         { "/test.html", "text/html" },
 127 };
 128
 129 /* this protocol server (always the first one) just knows how to do HTTP */
 130
 131 static int callback_http(struct libwebsocket_context *context,
 132                 struct libwebsocket *wsi,
 133                 enum libwebsocket_callback_reasons reason, void *user,
 134                                                            void *in, size_t len)
 135 {
 136         char client_name[128];
 137         char client_ip[128];
 138         char buf[256];
 139         int n;
 140 #ifdef EXTERNAL_POLL
 141         int m, m1;
 142         int hash, hash1;
 143         int fd = (int)(long)user;
 144 #endif
 145
 146         switch (reason) {
 147         case LWS_CALLBACK_HTTP:
 148
 149                 for (n = 0; n < (sizeof(whitelist) / sizeof(whitelist[0]) - 1); n++)
 150                         if (in && strcmp(in, whitelist[n].urlpath) == 0)
 151                                 break;
 152
 153                 sprintf(buf, LOCAL_RESOURCE_PATH"%s", whitelist[n].urlpath);
 154
 155                 if (libwebsockets_serve_http_file(context, wsi, buf, whitelist[n].mimetype))
 156                         fprintf(stderr, "Failed to send HTTP file\n");
 157
 158                 /*
 159                  * notice that the sending of the file completes asynchronously,
 160                  * we'll get a LWS_CALLBACK_HTTP_FILE_COMPLETION callback when
 161                  * it's done
 162                  */
 163
 164                 break;
 165
 166         case LWS_CALLBACK_HTTP_FILE_COMPLETION:
 167 //              fprintf(stderr, "LWS_CALLBACK_HTTP_FILE_COMPLETION seen\n");
 168                 /* kill the connection after we sent one file */
 169                 return 1;
 170
 171         /*
 172          * callback for confirming to continue with client IP appear in
 173          * protocol 0 callback since no websocket protocol has been agreed
 174          * yet.  You can just ignore this if you won't filter on client IP
 175          * since the default uhandled callback return is 0 meaning let the
 176          * connection continue.
 177          */
 178
 179         case LWS_CALLBACK_FILTER_NETWORK_CONNECTION:
 180
 181                 libwebsockets_get_peer_addresses((int)(long)user, client_name,
 182                              sizeof(client_name), client_ip, sizeof(client_ip));
 183
 184 //              fprintf(stderr, "Received network connect from %s (%s)\n",
 185 //                                                      client_name, client_ip);
 186
 187                 /* if we returned non-zero from here, we kill the connection */
 188                 break;
 189
 190 #ifdef EXTERNAL_POLL
 191         /*
 192          * callbacks for managing the external poll() array appear in
 193          * protocol 0 callback
 194          */
 195
 196         case LWS_CALLBACK_ADD_POLL_FD:
 197                 if (count_pollfds == MAX_POLL_ELEMENTS) {
 198                         fprintf(stderr, "LWS_CALLBACK_ADD_POLL_FD: too many sockets to track\n");
 199                         return 1;
 200                 }
 201                 hash = POLL_HASH(fd);
 202                 if (pollfd_count[hash] == POLL_ENTRIES_PER_BUCKET) {
 203                         fprintf(stderr, "LWS_CALLBACK_ADD_POLL_FD: hash table overflow\n");
 204                         return 1;
 205                 }
 206
 207 //              fprintf(stderr, "Adding fd %d at pollfd_maps[%d][%d], pollfds[%d]\n", fd, hash, pollfd_count[hash], count_pollfds);
 208
 209                 pollfd_maps[hash][pollfd_count[hash]].fd = fd;
 210                 pollfd_maps[hash][pollfd_count[hash]++].index = count_pollfds;
 211
 212                 pollfds[count_pollfds].fd = (int)(long)user;
 213                 pollfds[count_pollfds].events = (int)len;
 214                 pollfds[count_pollfds++].revents = 0;
 215                 break;
 216
 217         case LWS_CALLBACK_DEL_POLL_FD:
 218                 hash = POLL_HASH(fd);
 219                 n = find_poll_map_index(hash, fd);
 220                 if (n < 0) {
 221                         fprintf(stderr, "unable to find fd %d in poll_maps\n", fd);
 222                         return 1;
 223                 }
 224                 m = pollfd_maps[hash][n].index;
 225
 226                 assert(pollfds[m].fd == fd);
 227                 assert(count_pollfds);
 228                 assert(pollfd_count[hash]);
 229
 230 //              fprintf(stderr, "Removing fd %d at pollfd_maps[%d][%d], pollfds[%d]\n", fd, hash, n, m);
 231
 232                 /*
 233                  * swap the end guy into our vacant slot...
 234                  * works ok if n is the end guy
 235                  */
 236
 237                 count_pollfds--;
 238                 if (count_pollfds) {
 239
 240                         /* end guy... */
 241                         hash1 = POLL_HASH(pollfds[count_pollfds].fd);
 242                         m1 = find_poll_map_index(hash1, pollfds[count_pollfds].fd);
 243                         /* your index has changed... */
 244                         pollfd_maps[hash1][m1].index = m;
 245
 246                         pollfds[m] = pollfds[count_pollfds];
 247                         pollfds[count_pollfds].fd = -1;
 248                 }
 249
 250                 /*
 251                  * similar trick with hashtable
 252                  * old end guy goes into vacant slot in hash table
 253                  */
 254
 255                 pollfd_count[hash]--;
 256                 if (pollfd_count[hash]) {
 257                         pollfd_maps[hash][n].index = pollfd_maps[hash][pollfd_count[hash]].index;
 258                         pollfd_maps[hash][n].fd = pollfd_maps[hash][pollfd_count[hash]].fd;
 259                 }
 260                 break;
 261
 262         case LWS_CALLBACK_SET_MODE_POLL_FD:
 263                 n = find_pollfd_index(fd);
 264                 if (n < 0) {
 265                         fprintf(stderr, "unable to find fd %d\n", fd);
 266                         return 1;
 267                 }
 268                 if(pollfds[n].fd != fd) {
 269                         fprintf(stderr, "Setting fd %d, found at pollfd_index %d, actually fd %d\n", fd, n, pollfds[n].fd);
 270                         assert(0);
 271                 }
 272                 pollfds[n].events |= (int)(long)len;
 273                 break;
 274
 275         case LWS_CALLBACK_CLEAR_MODE_POLL_FD:
 276                 n = find_pollfd_index(fd);
 277                 if (n < 0) {
 278                         fprintf(stderr, "unable to find fd %d\n", fd);
 279                         return 1;
 280                 }
 281                 assert(pollfds[n].fd == fd);
 282                 pollfds[n].events &= ~(int)(long)len;
 283                 break;
 284 #endif
 285         default:
 286                 break;
 287         }
 288
 289         return 0;
 290 }
 291
 292
 293 /*
 294  * this is just an example of parsing handshake headers, you don't need this
 295  * in your code unless you will filter allowing connections by the header
 296  * content
 297  */
 298
 299 static void
 300 dump_handshake_info(struct lws_tokens *lwst)
 301 {
 302         int n;
 303         static const char *token_names[WSI_TOKEN_COUNT] = {
 304                 /*[WSI_TOKEN_GET_URI]           =*/ "GET URI",
 305                 /*[WSI_TOKEN_HOST]              =*/ "Host",
 306                 /*[WSI_TOKEN_CONNECTION]        =*/ "Connection",
 307                 /*[WSI_TOKEN_KEY1]              =*/ "key 1",
 308                 /*[WSI_TOKEN_KEY2]              =*/ "key 2",
 309                 /*[WSI_TOKEN_PROTOCOL]          =*/ "Protocol",
 310                 /*[WSI_TOKEN_UPGRADE]           =*/ "Upgrade",
 311                 /*[WSI_TOKEN_ORIGIN]            =*/ "Origin",
 312                 /*[WSI_TOKEN_DRAFT]             =*/ "Draft",
 313                 /*[WSI_TOKEN_CHALLENGE]         =*/ "Challenge",
 314
 315                 /* new for 04 */
 316                 /*[WSI_TOKEN_KEY]               =*/ "Key",
 317                 /*[WSI_TOKEN_VERSION]           =*/ "Version",
 318                 /*[WSI_TOKEN_SWORIGIN]          =*/ "Sworigin",
 319
 320                 /* new for 05 */
 321                 /*[WSI_TOKEN_EXTENSIONS]        =*/ "Extensions",
 322
 323                 /* client receives these */
 324                 /*[WSI_TOKEN_ACCEPT]            =*/ "Accept",
 325                 /*[WSI_TOKEN_NONCE]             =*/ "Nonce",
 326                 /*[WSI_TOKEN_HTTP]              =*/ "Http",
 327                 /*[WSI_TOKEN_MUXURL]    =*/ "MuxURL",
 328         };
 329
 330         for (n = 0; n < WSI_TOKEN_COUNT; n++) {
 331                 if (lwst[n].token == NULL)
 332                         continue;
 333
 334                 fprintf(stderr, "    %s = %s\n", token_names[n], lwst[n].token);
 335         }
 336 }
 337
 338 /* dumb_increment protocol */
 339
 340 /*
 341  * one of these is auto-created for each connection and a pointer to the
 342  * appropriate instance is passed to the callback in the user parameter
 343  *
 344  * for this example protocol we use it to individualize the count for each
 345  * connection.
 346  */
 347
 348 struct per_session_data__dumb_increment {
 349         int number;
 350 };
 351
 352 static int
 353 callback_dumb_increment(struct libwebsocket_context *context,
 354                         struct libwebsocket *wsi,
 355                         enum libwebsocket_callback_reasons reason,
 356                                                void *user, void *in, size_t len)
 357 {
 358         int n;
 359         unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + 512 +
 360                                                   LWS_SEND_BUFFER_POST_PADDING];
 361         unsigned char *p = &buf[LWS_SEND_BUFFER_PRE_PADDING];
 362         struct per_session_data__dumb_increment *pss = user;
 363
 364         switch (reason) {
 365
 366         case LWS_CALLBACK_ESTABLISHED:
 367                 fprintf(stderr, "callback_dumb_increment: "
 368                                                  "LWS_CALLBACK_ESTABLISHED\n");
 369                 pss->number = 0;
 370                 break;
 371
 372         /*
 373          * in this protocol, we just use the broadcast action as the chance to
 374          * send our own connection-specific data and ignore the broadcast info
 375          * that is available in the 'in' parameter
 376          */
 377
 378         case LWS_CALLBACK_BROADCAST:
 379                 n = sprintf((char *)p, "%d", pss->number++);
 380                 n = libwebsocket_write(wsi, p, n, LWS_WRITE_TEXT);
 381                 if (n < 0) {
 382                         fprintf(stderr, "ERROR %d writing to socket\n", n);
 383                         return 1;
 384                 }
 385                 if (close_testing && pss->number == 50) {
 386                         fprintf(stderr, "close tesing limit, closing\n");
 387                         libwebsocket_close_and_free_session(context, wsi,
 388                                                        LWS_CLOSE_STATUS_NORMAL);
 389                 }
 390                 break;
 391
 392         case LWS_CALLBACK_RECEIVE:
 393                 fprintf(stderr, "rx %d\n", (int)len);
 394                 if (len < 6)
 395                         break;
 396                 if (strcmp(in, "reset\n") == 0)
 397                         pss->number = 0;
 398                 break;
 399         /*
 400          * this just demonstrates how to use the protocol filter. If you won't
 401          * study and reject connections based on header content, you don't need
 402          * to handle this callback
 403          */
 404
 405         case LWS_CALLBACK_FILTER_PROTOCOL_CONNECTION:
 406                 dump_handshake_info((struct lws_tokens *)(long)user);
 407                 /* you could return non-zero here and kill the connection */
 408                 break;
 409
 410         default:
 411                 break;
 412         }
 413
 414         return 0;
 415 }
 416
 417
 418 /* lws-mirror_protocol */
 419
 420 #define MAX_MESSAGE_QUEUE 64
 421
 422 struct per_session_data__lws_mirror {
 423         struct libwebsocket *wsi;
 424         int ringbuffer_tail;
 425 };
 426
 427 struct a_message {
 428         void *payload;
 429         size_t len;
 430 };
 431
 432 static struct a_message ringbuffer[MAX_MESSAGE_QUEUE];
 433 static int ringbuffer_head;
 434
 435
 436 static int
 437 callback_lws_mirror(struct libwebsocket_context *context,
 438                         struct libwebsocket *wsi,
 439                         enum libwebsocket_callback_reasons reason,
 440                                                void *user, void *in, size_t len)
 441 {
 442         int n;
 443         struct per_session_data__lws_mirror *pss = user;
 444
 445         switch (reason) {
 446
 447         case LWS_CALLBACK_ESTABLISHED:
 448                 fprintf(stderr, "callback_lws_mirror: "
 449                                                  "LWS_CALLBACK_ESTABLISHED\n");
 450                 pss->ringbuffer_tail = ringbuffer_head;
 451                 pss->wsi = wsi;
 452                 break;
 453
 454         case LWS_CALLBACK_SERVER_WRITEABLE:
 455                 if (close_testing)
 456                         break;
 457                 if (pss->ringbuffer_tail != ringbuffer_head) {
 458
 459                         n = libwebsocket_write(wsi, (unsigned char *)
 460                                    ringbuffer[pss->ringbuffer_tail].payload +
 461                                    LWS_SEND_BUFFER_PRE_PADDING,
 462                                    ringbuffer[pss->ringbuffer_tail].len,
 463                                                                 LWS_WRITE_TEXT);
 464                         if (n < 0) {
 465                                 fprintf(stderr, "ERROR %d writing to socket\n", n);
 466                                 exit(1);
 467                         }
 468
 469                         if (pss->ringbuffer_tail == (MAX_MESSAGE_QUEUE - 1))
 470                                 pss->ringbuffer_tail = 0;
 471                         else
 472                                 pss->ringbuffer_tail++;
 473
 474                         if (((ringbuffer_head - pss->ringbuffer_tail) %
 475                                   MAX_MESSAGE_QUEUE) < (MAX_MESSAGE_QUEUE - 15))
 476                                 libwebsocket_rx_flow_control(wsi, 1);
 477
 478                         libwebsocket_callback_on_writable(context, wsi);
 479
 480                 }
 481                 break;
 482
 483         case LWS_CALLBACK_BROADCAST:
 484                 n = libwebsocket_write(wsi, in, len, LWS_WRITE_TEXT);
 485                 if (n < 0)
 486                         fprintf(stderr, "mirror write failed\n");
 487                 break;
 488
 489         case LWS_CALLBACK_RECEIVE:
 490
 491                 if (ringbuffer[ringbuffer_head].payload)
 492                         free(ringbuffer[ringbuffer_head].payload);
 493
 494                 ringbuffer[ringbuffer_head].payload =
 495                                 malloc(LWS_SEND_BUFFER_PRE_PADDING + len +
 496                                                   LWS_SEND_BUFFER_POST_PADDING);
 497                 ringbuffer[ringbuffer_head].len = len;
 498                 memcpy((char *)ringbuffer[ringbuffer_head].payload +
 499                                           LWS_SEND_BUFFER_PRE_PADDING, in, len);
 500                 if (ringbuffer_head == (MAX_MESSAGE_QUEUE - 1))
 501                         ringbuffer_head = 0;
 502                 else
 503                         ringbuffer_head++;
 504
 505                 if (((ringbuffer_head - pss->ringbuffer_tail) %
 506                                   MAX_MESSAGE_QUEUE) > (MAX_MESSAGE_QUEUE - 10))
 507                         libwebsocket_rx_flow_control(wsi, 0);
 508
 509                 libwebsocket_callback_on_writable_all_protocol(
 510                                                libwebsockets_get_protocol(wsi));
 511                 break;
 512         /*
 513          * this just demonstrates how to use the protocol filter. If you won't
 514          * study and reject connections based on header content, you don't need
 515          * to handle this callback
 516          */
 517
 518         case LWS_CALLBACK_FILTER_PROTOCOL_CONNECTION:
 519                 dump_handshake_info((struct lws_tokens *)(long)user);
 520                 /* you could return non-zero here and kill the connection */
 521                 break;
 522
 523         default:
 524                 break;
 525         }
 526
 527         return 0;
 528 }
 529
 530
 531 /* list of supported protocols and callbacks */
 532
 533 static struct libwebsocket_protocols protocols[] = {
 534         /* first protocol must always be HTTP handler */
 535
 536         {
 537                 "http-only",            /* name */
 538                 callback_http,          /* callback */
 539                 0                       /* per_session_data_size */
 540         },
 541         {
 542                 "dumb-increment-protocol",
 543                 callback_dumb_increment,
 544                 sizeof(struct per_session_data__dumb_increment),
 545         },
 546         {
 547                 "lws-mirror-protocol",
 548                 callback_lws_mirror,
 549                 sizeof(struct per_session_data__lws_mirror)
 550         },
 551         {
 552                 NULL, NULL, 0           /* End of list */
 553         }
 554 };
 555
 556 static struct option options[] = {
 557         { "help",       no_argument,            NULL, 'h' },
 558         { "debug",      required_argument,      NULL, 'd' },
 559         { "port",       required_argument,      NULL, 'p' },
 560         { "ssl",        no_argument,            NULL, 's' },
 561         { "killmask",   no_argument,            NULL, 'k' },
 562         { "interface",  required_argument,      NULL, 'i' },
 563         { "closetest",  no_argument,            NULL, 'c' },
 564         { NULL, 0, 0, 0 }
 565 };
 566
 567 int main(int argc, char **argv)
 568 {
 569         int n = 0;
 570         const char *cert_path =
 571                             LOCAL_RESOURCE_PATH"/libwebsockets-test-server.pem";
 572         const char *key_path =
 573                         LOCAL_RESOURCE_PATH"/libwebsockets-test-server.key.pem";
 574         unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + 1024 +
 575                                                   LWS_SEND_BUFFER_POST_PADDING];
 576         int port = 7681;
 577         int use_ssl = 0;
 578         struct libwebsocket_context *context;
 579         int opts = 0;
 580         char interface_name[128] = "";
 581         const char *interface = NULL;
 582 #ifdef LWS_NO_FORK
 583         unsigned int oldus = 0;
 584 #endif
 585
 586         fprintf(stderr, "libwebsockets test server\n"
 587                         "(C) Copyright 2010-2013 Andy Green <andy@warmcat.com> "
 588                                                     "licensed under LGPL2.1\n");
 589
 590         while (n >= 0) {
 591                 n = getopt_long(argc, argv, "ci:khsp:d:", options, NULL);
 592                 if (n < 0)
 593                         continue;
 594                 switch (n) {
 595                 case 'd':
 596                         lws_set_log_level(atoi(optarg), NULL);
 597                         break;
 598                 case 's':
 599                         use_ssl = 1;
 600                         break;
 601                 case 'k':
 602                         opts = LWS_SERVER_OPTION_DEFEAT_CLIENT_MASK;
 603                         break;
 604                 case 'p':
 605                         port = atoi(optarg);
 606                         break;
 607                 case 'i':
 608                         strncpy(interface_name, optarg, sizeof interface_name);
 609                         interface_name[(sizeof interface_name) - 1] = '\0';
 610                         interface = interface_name;
 611                         break;
 612                 case 'c':
 613                         close_testing = 1;
 614                         fprintf(stderr, " Close testing mode -- closes on "
 615                                            "client after 50 dumb increments"
 616                                            "and suppresses lws_mirror spam\n");
 617                         break;
 618                 case 'h':
 619                         fprintf(stderr, "Usage: test-server "
 620                                         "[--port=<p>] [--ssl] "
 621                                         "[-d <log bitfield>]\n");
 622                         exit(1);
 623                 }
 624         }
 625
 626         if (!use_ssl)
 627                 cert_path = key_path = NULL;
 628
 629         context = libwebsocket_create_context(port, interface, protocols,
 630                                 libwebsocket_internal_extensions,
 631                                 cert_path, key_path, NULL, -1, -1, opts, NULL);
 632         if (context == NULL) {
 633                 fprintf(stderr, "libwebsocket init failed\n");
 634                 return -1;
 635         }
 636
 637         buf[LWS_SEND_BUFFER_PRE_PADDING] = 'x';
 638
 639 #ifdef LWS_NO_FORK
 640
 641         /*
 642          * This example shows how to work with no forked service loop
 643          */
 644
 645         fprintf(stderr, " Using no-fork service loop\n");
 646
 647         n = 0;
 648         while (n >= 0) {
 649                 struct timeval tv;
 650
 651                 gettimeofday(&tv, NULL);
 652
 653                 /*
 654                  * This broadcasts to all dumb-increment-protocol connections
 655                  * at 20Hz.
 656                  *
 657                  * We're just sending a character 'x', in these examples the
 658                  * callbacks send their own per-connection content.
 659                  *
 660                  * You have to send something with nonzero length to get the
 661                  * callback actions delivered.
 662                  *
 663                  * We take care of pre-and-post padding allocation.
 664                  */
 665
 666                 if (((unsigned int)tv.tv_usec - oldus) > 50000) {
 667                         libwebsockets_broadcast(
 668                                         &protocols[PROTOCOL_DUMB_INCREMENT],
 669                                         &buf[LWS_SEND_BUFFER_PRE_PADDING], 1);
 670                         oldus = tv.tv_usec;
 671                 }
 672
 673                 /*
 674                  * This example server does not fork or create a thread for
 675                  * websocket service, it all runs in this single loop.  So,
 676                  * we have to give the websockets an opportunity to service
 677                  * "manually".
 678                  *
 679                  * If no socket is needing service, the call below returns
 680                  * immediately and quickly.  Negative return means we are
 681                  * in process of closing
 682                  */
 683 #ifdef EXTERNAL_POLL
 684
 685                 /*
 686                  * this represents an existing server's single poll action
 687                  * which also includes libwebsocket sockets
 688                  */
 689
 690                 n = poll(pollfds, count_pollfds, 50);
 691                 if (n < 0)
 692                         continue;
 693
 694
 695                 if (n)
 696                         for (n = 0; n < count_pollfds; n++)
 697                                 if (pollfds[n].revents)
 698                                         /*
 699                                         * returns immediately if the fd does not
 700                                         * match anything under libwebsockets
 701                                         * control
 702                                         */
 703                                         if (libwebsocket_service_fd(context,
 704                                                                   &pollfds[n]) < 0)
 705                                                 goto done;
 706 #else
 707                 n = libwebsocket_service(context, 50);
 708 #endif
 709         }
 710
 711 #else /* !LWS_NO_FORK */
 712
 713         /*
 714          * This example shows how to work with the forked websocket service loop
 715          */
 716
 717         fprintf(stderr, " Using forked service loop\n");
 718
 719         /*
 720          * This forks the websocket service action into a subprocess so we
 721          * don't have to take care about it.
 722          */
 723
 724         n = libwebsockets_fork_service_loop(context);
 725         if (n < 0) {
 726                 fprintf(stderr, "Unable to fork service loop %d\n", n);
 727                 return 1;
 728         }
 729
 730         while (1) {
 731
 732                 usleep(50000);
 733
 734                 /*
 735                  * This broadcasts to all dumb-increment-protocol connections
 736                  * at 20Hz.
 737                  *
 738                  * We're just sending a character 'x', in these examples the
 739                  * callbacks send their own per-connection content.
 740                  *
 741                  * You have to send something with nonzero length to get the
 742                  * callback actions delivered.
 743                  *
 744                  * We take care of pre-and-post padding allocation.
 745                  */
 746
 747                 libwebsockets_broadcast(&protocols[PROTOCOL_DUMB_INCREMENT],
 748                                         &buf[LWS_SEND_BUFFER_PRE_PADDING], 1);
 749         }
 750
 751 #endif
 752 #ifdef EXTERNAL_POLL
 753 done:
 754 #endif
 755
 756         libwebsocket_context_destroy(context);
 757
 758         return 0;
 759 }