lib/client.c

   1 /*
   2  * libwebsockets - small server side websockets and web server implementation
   3  *
   4  * Copyright (C) 2010-2013 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 #ifdef WIN32
  25 #include <tchar.h>
  26 #include <io.h>
  27 #else
  28 #ifdef LWS_BUILTIN_GETIFADDRS
  29 #include <getifaddrs.h>
  30 #else
  31 #include <ifaddrs.h>
  32 #endif
  33 #include <sys/un.h>
  34 #include <sys/socket.h>
  35 #include <netdb.h>
  36 #endif
  37
  38 #ifdef LWS_OPENSSL_SUPPORT
  39 extern int openssl_websocket_private_data_index;
  40 #endif
  41
  42 int lws_client_socket_service(struct libwebsocket_context *context, struct libwebsocket *wsi, struct pollfd *pollfd)
  43 {
  44         int n;
  45         char pkt[1024];
  46         char *p = &pkt[0];
  47         int len;
  48         char c;
  49 #ifdef LWS_OPENSSL_SUPPORT
  50         char ssl_err_buf[512];
  51 #endif
  52
  53         switch (wsi->mode) {
  54
  55         case LWS_CONNMODE_WS_CLIENT_WAITING_PROXY_REPLY:
  56
  57                 /* handle proxy hung up on us */
  58
  59                 if (pollfd->revents & (POLLERR | POLLHUP)) {
  60
  61                         lwsl_warn("Proxy connection %p (fd=%d) dead\n",
  62                                 (void *)wsi, pollfd->fd);
  63
  64                         libwebsocket_close_and_free_session(context, wsi,
  65                                                      LWS_CLOSE_STATUS_NOSTATUS);
  66                         return 0;
  67                 }
  68
  69                 n = recv(wsi->sock, pkt, sizeof pkt, 0);
  70                 if (n < 0) {
  71                         libwebsocket_close_and_free_session(context, wsi,
  72                                                      LWS_CLOSE_STATUS_NOSTATUS);
  73                         lwsl_err("ERROR reading from proxy socket\n");
  74                         return 0;
  75                 }
  76
  77                 pkt[13] = '\0';
  78                 if (strcmp(pkt, "HTTP/1.0 200 ") != 0) {
  79                         libwebsocket_close_and_free_session(context, wsi,
  80                                                      LWS_CLOSE_STATUS_NOSTATUS);
  81                         lwsl_err("ERROR from proxy: %s\n", pkt);
  82                         return 0;
  83                 }
  84
  85                 /* clear his proxy connection timeout */
  86
  87                 libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
  88
  89                 /* fallthru */
  90
  91         case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE:
  92
  93                 /*
  94                  * we are under PENDING_TIMEOUT_SENT_CLIENT_HANDSHAKE
  95                  * timeout protection set in client-handshake.c
  96                  */
  97
  98         #ifdef LWS_OPENSSL_SUPPORT
  99
 100                 /*
 101                  * take care of our libwebsocket_callback_on_writable
 102                  * happening at a time when there's no real connection yet
 103                  */
 104
 105                 pollfd->events &= ~POLLOUT;
 106
 107                 /* external POLL support via protocol 0 */
 108                 context->protocols[0].callback(context, wsi,
 109                         LWS_CALLBACK_CLEAR_MODE_POLL_FD,
 110                         (void *)(long)wsi->sock, NULL, POLLOUT);
 111
 112                 /* we can retry this... so just cook the SSL BIO the first time */
 113
 114                 if (wsi->use_ssl && !wsi->ssl) {
 115
 116                         wsi->ssl = SSL_new(context->ssl_client_ctx);
 117                         wsi->client_bio = BIO_new_socket(wsi->sock,
 118                                                                    BIO_NOCLOSE);
 119                         SSL_set_bio(wsi->ssl, wsi->client_bio, wsi->client_bio);
 120
 121                         SSL_set_ex_data(wsi->ssl,
 122                                         openssl_websocket_private_data_index,
 123                                                                        context);
 124                 }
 125
 126                 if (wsi->use_ssl) {
 127                         n = SSL_connect(wsi->ssl);
 128
 129                         if (n < 0) {
 130                                 n = SSL_get_error(wsi->ssl, n);
 131
 132                                 if (n == SSL_ERROR_WANT_READ ||
 133                                         n == SSL_ERROR_WANT_WRITE) {
 134                                         /*
 135                                          * wants us to retry connect due to state of the
 136                                          * underlying ssl layer... but since it may be
 137                                          * stalled on blocked write, no incoming data may
 138                                          * arrive to trigger the retry.  Force (possibly
 139                                          * many if the SSL state persists in returning the
 140                                          * condition code, but other sockets are getting
 141                                          * serviced inbetweentimes) us to get called back
 142                                          * when writable.
 143                                          */
 144
 145                                         lwsl_info("SSL_connect -> SSL_ERROR_WANT_... retrying\n");
 146                                         libwebsocket_callback_on_writable(context, wsi);
 147
 148                                         return 0; /* no error */
 149                                 }
 150                                 n = -1;
 151                         }
 152
 153                         if (n <= 0) {
 154                                 /*
 155                                  * retry if new data comes until we
 156                                  * run into the connection timeout or win
 157                                  */
 158
 159                                 lwsl_err("SSL connect error %s\n",
 160                                         ERR_error_string(ERR_get_error(),
 161                                                                   ssl_err_buf));
 162                                 return 0;
 163                         }
 164
 165                         n = SSL_get_verify_result(wsi->ssl);
 166                         if ((n != X509_V_OK) && (
 167                                 n != X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT ||
 168                                                            wsi->use_ssl != 2)) {
 169
 170                                 lwsl_err("server's cert didn't "
 171                                                            "look good %d\n", n);
 172                                 libwebsocket_close_and_free_session(context,
 173                                                 wsi, LWS_CLOSE_STATUS_NOSTATUS);
 174                                 return 0;
 175                         }
 176                 } else
 177                         wsi->ssl = NULL;
 178         #endif
 179
 180                 p = libwebsockets_generate_client_handshake(context, wsi, p);
 181                 if (p == NULL) {
 182                         lwsl_err("Failed to generate handshake for client, closing it\n");
 183                         libwebsocket_close_and_free_session(context, wsi,
 184                                                      LWS_CLOSE_STATUS_NOSTATUS);
 185                         return 0;
 186                 }
 187
 188                 /* send our request to the server */
 189
 190         #ifdef LWS_OPENSSL_SUPPORT
 191                 if (wsi->use_ssl)
 192                         n = SSL_write(wsi->ssl, pkt, p - pkt);
 193                 else
 194         #endif
 195                         n = send(wsi->sock, pkt, p - pkt, 0);
 196
 197                 if (n < 0) {
 198                         lwsl_debug("ERROR writing to client socket\n");
 199                         libwebsocket_close_and_free_session(context, wsi,
 200                                                      LWS_CLOSE_STATUS_NOSTATUS);
 201                         return 0;
 202                 }
 203
 204                 wsi->parser_state = WSI_TOKEN_NAME_PART;
 205                 wsi->lextable_pos = 0;
 206                 wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY;
 207                 libwebsocket_set_timeout(wsi,
 208                                 PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE, AWAITING_TIMEOUT);
 209
 210                 break;
 211
 212         case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 213
 214                 /* handle server hung up on us */
 215
 216                 if (pollfd->revents & (POLLERR | POLLHUP)) {
 217
 218                         lwsl_debug("Server connection %p (fd=%d) dead\n",
 219                                 (void *)wsi, pollfd->fd);
 220
 221                         goto bail3;
 222                 }
 223
 224
 225                 /* interpret the server response */
 226
 227                 /*
 228                  *  HTTP/1.1 101 Switching Protocols
 229                  *  Upgrade: websocket
 230                  *  Connection: Upgrade
 231                  *  Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
 232                  *  Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
 233                  *  Sec-WebSocket-Protocol: chat
 234                  */
 235
 236                 /*
 237                  * we have to take some care here to only take from the
 238                  * socket bytewise.  The browser may (and has been seen to
 239                  * in the case that onopen() performs websocket traffic)
 240                  * coalesce both handshake response and websocket traffic
 241                  * in one packet, since at that point the connection is
 242                  * definitively ready from browser pov.
 243                  */
 244
 245                 len = 1;
 246                 while (wsi->parser_state != WSI_PARSING_COMPLETE && len > 0) {
 247 #ifdef LWS_OPENSSL_SUPPORT
 248                         if (wsi->use_ssl)
 249                                 len = SSL_read(wsi->ssl, &c, 1);
 250                          else
 251 #endif
 252                                 len = recv(wsi->sock, &c, 1, 0);
 253
 254                         libwebsocket_parse(wsi, c);
 255                 }
 256
 257                 /*
 258                  * hs may also be coming in multiple packets, there is a 5-sec
 259                  * libwebsocket timeout still active here too, so if parsing did
 260                  * not complete just wait for next packet coming in this state
 261                  */
 262
 263                 if (wsi->parser_state != WSI_PARSING_COMPLETE)
 264                         break;
 265
 266                 /*
 267                  * otherwise deal with the handshake.  If there's any
 268                  * packet traffic already arrived we'll trigger poll() again
 269                  * right away and deal with it that way
 270                  */
 271
 272                 return lws_client_interpret_server_handshake(context, wsi);
 273
 274 bail3:
 275                 if (wsi->c_protocol)
 276                         free(wsi->c_protocol);
 277                 libwebsocket_close_and_free_session(context, wsi,
 278                                                     LWS_CLOSE_STATUS_NOSTATUS);
 279                 return 0;
 280
 281         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 282                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
 283                 break;
 284
 285         case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
 286                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
 287                 break;
 288         default:
 289                 break;
 290         }
 291
 292         return 0;
 293 }
 294
 295
 296 /*
 297  * In-place str to lower case
 298  */
 299
 300 static void
 301 strtolower(char *s)
 302 {
 303         while (*s) {
 304                 *s = tolower(*s);
 305                 s++;
 306         }
 307 }
 308
 309 int
 310 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
 311                 struct libwebsocket *wsi)
 312 {
 313         const char *pc;
 314         int okay = 0;
 315 #ifndef LWS_NO_EXTENSIONS
 316         char ext_name[128];
 317         struct libwebsocket_extension *ext;
 318         void *v;
 319         int more = 1;
 320         const char *c;
 321 #endif
 322         int n;
 323
 324         /*
 325          * well, what the server sent looked reasonable for syntax.
 326          * Now let's confirm it sent all the necessary headers
 327          */
 328 #if 0
 329         lwsl_parser("WSI_TOKEN_HTTP: %d\n",
 330                                     wsi->utf8_token[WSI_TOKEN_HTTP].token_len);
 331         lwsl_parser("WSI_TOKEN_UPGRADE: %d\n",
 332                                  wsi->utf8_token[WSI_TOKEN_UPGRADE].token_len);
 333         lwsl_parser("WSI_TOKEN_CONNECTION: %d\n",
 334                               wsi->utf8_token[WSI_TOKEN_CONNECTION].token_len);
 335         lwsl_parser("WSI_TOKEN_ACCEPT: %d\n",
 336                                   wsi->utf8_token[WSI_TOKEN_ACCEPT].token_len);
 337         lwsl_parser("WSI_TOKEN_NONCE: %d\n",
 338                                    wsi->utf8_token[WSI_TOKEN_NONCE].token_len);
 339         lwsl_parser("WSI_TOKEN_PROTOCOL: %d\n",
 340                                 wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len);
 341 #endif
 342
 343         strtolower(wsi->utf8_token[WSI_TOKEN_HTTP].token);
 344         if (strncmp(wsi->utf8_token[WSI_TOKEN_HTTP].token, "101", 3)) {
 345                 lwsl_warn("libwebsocket_client_handshake "
 346                                 "server sent bad HTTP response '%s'\n",
 347                                  wsi->utf8_token[WSI_TOKEN_HTTP].token);
 348                 goto bail3;
 349         }
 350
 351         strtolower(wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
 352         if (strcmp(wsi->utf8_token[WSI_TOKEN_UPGRADE].token,
 353                                                          "websocket")) {
 354                 lwsl_warn("libwebsocket_client_handshake server "
 355                                 "sent bad Upgrade header '%s'\n",
 356                                   wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
 357                 goto bail3;
 358         }
 359
 360         strtolower(wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
 361         if (strcmp(wsi->utf8_token[WSI_TOKEN_CONNECTION].token,
 362                                                            "upgrade")) {
 363                 lwsl_warn("libwebsocket_client_handshake server "
 364                                 "sent bad Connection hdr '%s'\n",
 365                            wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
 366                 goto bail3;
 367         }
 368
 369         pc = wsi->c_protocol;
 370         if (pc == NULL)
 371                 lwsl_parser("lws_client_interpret_server_handshake: "
 372                                                           "NULL c_protocol\n");
 373         else
 374                 lwsl_parser("lws_client_interpret_server_handshake: "
 375                                                       "cPprotocol='%s'\n", pc);
 376
 377         /*
 378          * confirm the protocol the server wants to talk was in the list
 379          * of protocols we offered
 380          */
 381
 382         if (!wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len) {
 383
 384                 lwsl_info("lws_client_interpret_server_handshake "
 385                                                "WSI_TOKEN_PROTOCOL is null\n");
 386                 /*
 387                  * no protocol name to work from,
 388                  * default to first protocol
 389                  */
 390                 wsi->protocol = &context->protocols[0];
 391                 wsi->c_callback = wsi->protocol->callback;
 392                 free(wsi->c_protocol);
 393
 394                 goto check_extensions;
 395         }
 396
 397         while (*pc && !okay) {
 398                 if ((!strncmp(pc, wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
 399                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len)) &&
 400                  (pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == ',' ||
 401                   pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == '\0')) {
 402                         okay = 1;
 403                         continue;
 404                 }
 405                 while (*pc && *pc != ',')
 406                         pc++;
 407                 while (*pc && *pc != ' ')
 408                         pc++;
 409         }
 410
 411         /* done with him now */
 412
 413         if (wsi->c_protocol)
 414                 free(wsi->c_protocol);
 415
 416         if (!okay) {
 417                 lwsl_err("libwebsocket_client_handshake server "
 418                                         "sent bad protocol '%s'\n",
 419                                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
 420                 goto bail2;
 421         }
 422
 423         /*
 424          * identify the selected protocol struct and set it
 425          */
 426         n = 0;
 427         wsi->protocol = NULL;
 428         while (context->protocols[n].callback && !wsi->protocol) {  /* Stop after finding first one?? */
 429                 if (strcmp(wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
 430                                            context->protocols[n].name) == 0) {
 431                         wsi->protocol = &context->protocols[n];
 432                         wsi->c_callback = wsi->protocol->callback;
 433                 }
 434                 n++;
 435         }
 436
 437         if (wsi->protocol == NULL) {
 438                 lwsl_err("libwebsocket_client_handshake server "
 439                                 "requested protocol '%s', which we "
 440                                 "said we supported but we don't!\n",
 441                                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
 442                 goto bail2;
 443         }
 444
 445
 446 check_extensions:
 447 #ifndef LWS_NO_EXTENSIONS
 448         /* instantiate the accepted extensions */
 449
 450         if (!wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token_len) {
 451                 lwsl_ext("no client extenstions allowed by server\n");
 452                 goto check_accept;
 453         }
 454
 455         /*
 456          * break down the list of server accepted extensions
 457          * and go through matching them or identifying bogons
 458          */
 459
 460         c = wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token;
 461         n = 0;
 462         while (more) {
 463
 464                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 465                         ext_name[n] = *c++;
 466                         if (n < sizeof(ext_name) - 1)
 467                                 n++;
 468                         continue;
 469                 }
 470                 ext_name[n] = '\0';
 471                 if (!*c)
 472                         more = 0;
 473                 else {
 474                         c++;
 475                         if (!n)
 476                                 continue;
 477                 }
 478
 479                 /* check we actually support it */
 480
 481                 lwsl_ext("checking client ext %s\n", ext_name);
 482
 483                 n = 0;
 484                 ext = wsi->protocol->owning_server->extensions;
 485                 while (ext && ext->callback) {
 486
 487                         if (strcmp(ext_name, ext->name)) {
 488                                 ext++;
 489                                 continue;
 490                         }
 491
 492                         n = 1;
 493
 494                         lwsl_ext("instantiating client ext %s\n", ext_name);
 495
 496                         /* instantiate the extension on this conn */
 497
 498                         wsi->active_extensions_user[
 499                                 wsi->count_active_extensions] =
 500                                          malloc(ext->per_session_data_size);
 501                         if (wsi->active_extensions_user[
 502                                 wsi->count_active_extensions] == NULL) {
 503                                 lwsl_err("Out of mem\n");
 504                                 goto bail2;
 505                         }
 506                         memset(wsi->active_extensions_user[
 507                                 wsi->count_active_extensions], 0,
 508                                                     ext->per_session_data_size);
 509                         wsi->active_extensions[
 510                                   wsi->count_active_extensions] = ext;
 511
 512                         /* allow him to construct his context */
 513
 514                         ext->callback(wsi->protocol->owning_server,
 515                                 ext, wsi,
 516                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 517                                         wsi->active_extensions_user[
 518                                          wsi->count_active_extensions],
 519                                                                    NULL, 0);
 520
 521                         wsi->count_active_extensions++;
 522
 523                         ext++;
 524                 }
 525
 526                 if (n == 0) {
 527                         lwsl_warn("Server said we should use"
 528                                   "an unknown extension '%s'!\n", ext_name);
 529                         goto bail2;
 530                 }
 531
 532                 n = 0;
 533         }
 534
 535 check_accept:
 536 #endif
 537
 538         /*
 539          * Confirm his accept token is the one we precomputed
 540          */
 541
 542         if (strcmp(wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
 543                                   wsi->initial_handshake_hash_base64)) {
 544                 lwsl_warn("libwebsocket_client_handshake server "
 545                         "sent bad ACCEPT '%s' vs computed '%s'\n",
 546                         wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
 547                                         wsi->initial_handshake_hash_base64);
 548                 goto bail2;
 549         }
 550
 551         /* allocate the per-connection user memory (if any) */
 552         if (wsi->protocol->per_session_data_size &&
 553                                           !libwebsocket_ensure_user_space(wsi))
 554                 goto bail2;
 555
 556         /* clear his proxy connection timeout */
 557
 558         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 559
 560         /* mark him as being alive */
 561
 562         wsi->state = WSI_STATE_ESTABLISHED;
 563         wsi->mode = LWS_CONNMODE_WS_CLIENT;
 564
 565         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 566
 567         /* call him back to inform him he is up */
 568
 569         wsi->protocol->callback(context, wsi,
 570                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 571                                                      wsi->user_space, NULL, 0);
 572 #ifndef LWS_NO_EXTENSIONS
 573         /*
 574          * inform all extensions, not just active ones since they
 575          * already know
 576          */
 577
 578         ext = context->extensions;
 579
 580         while (ext && ext->callback) {
 581                 v = NULL;
 582                 for (n = 0; n < wsi->count_active_extensions; n++)
 583                         if (wsi->active_extensions[n] == ext)
 584                                 v = wsi->active_extensions_user[n];
 585
 586                 ext->callback(context, ext, wsi,
 587                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 588                 ext++;
 589         }
 590 #endif
 591
 592         return 0;
 593
 594 bail3:
 595         if (wsi->c_protocol)
 596                 free(wsi->c_protocol);
 597
 598 bail2:
 599         if (wsi->c_callback) wsi->c_callback(context, wsi,
 600        LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 601                          wsi->user_space,
 602                          NULL, 0);
 603         libwebsocket_close_and_free_session(context, wsi,
 604                                                  LWS_CLOSE_STATUS_NOSTATUS);  // But this should be LWS_CLOSE_STATUS_PROTOCOL_ERR
 605
 606         return 1;
 607 }
 608
 609
 610 char *
 611 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 612                 struct libwebsocket *wsi, char *pkt)
 613 {
 614         char hash[20];
 615         char key_b64[40];
 616         char *p = pkt;
 617         int n;
 618 #ifndef LWS_NO_EXTENSIONS
 619         struct libwebsocket_extension *ext;
 620         struct libwebsocket_extension *ext1;
 621         int ext_count = 0;
 622 #endif
 623         unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + 1 +
 624                          MAX_BROADCAST_PAYLOAD + LWS_SEND_BUFFER_POST_PADDING];
 625         static const char magic_websocket_guid[] =
 626                                          "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 627
 628         /*
 629          * create the random key
 630          */
 631
 632         n = libwebsockets_get_random(context, hash, 16);
 633         if (n != 16) {
 634                 lwsl_err("Unable to read from random dev %s\n",
 635                                                 SYSTEM_RANDOM_FILEPATH);
 636                 free(wsi->c_path);
 637                 free(wsi->c_host);
 638                 if (wsi->c_origin)
 639                         free(wsi->c_origin);
 640                 if (wsi->c_protocol)
 641                         free(wsi->c_protocol);
 642                 libwebsocket_close_and_free_session(context, wsi,
 643                                              LWS_CLOSE_STATUS_NOSTATUS);
 644                 return NULL;
 645         }
 646
 647         lws_b64_encode_string(hash, 16, key_b64, sizeof key_b64);
 648
 649         /*
 650          * 00 example client handshake
 651          *
 652          * GET /socket.io/websocket HTTP/1.1
 653          * Upgrade: WebSocket
 654          * Connection: Upgrade
 655          * Host: 127.0.0.1:9999
 656          * Origin: http://127.0.0.1
 657          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 658          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 659          * Cookie: socketio=websocket
 660          *
 661          * (Á®Ä0¶†≥
 662          *
 663          * 04 example client handshake
 664          *
 665          * GET /chat HTTP/1.1
 666          * Host: server.example.com
 667          * Upgrade: websocket
 668          * Connection: Upgrade
 669          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 670          * Sec-WebSocket-Origin: http://example.com
 671          * Sec-WebSocket-Protocol: chat, superchat
 672          * Sec-WebSocket-Version: 4
 673          */
 674
 675         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a", wsi->c_path);
 676
 677         p += sprintf(p, "Pragma: no-cache\x0d\x0a"
 678                                         "Cache-Control: no-cache\x0d\x0a");
 679
 680         p += sprintf(p, "Host: %s\x0d\x0a", wsi->c_host);
 681         p += sprintf(p, "Upgrade: websocket\x0d\x0a"
 682                                         "Connection: Upgrade\x0d\x0a"
 683                                         "Sec-WebSocket-Key: ");
 684         strcpy(p, key_b64);
 685         p += strlen(key_b64);
 686         p += sprintf(p, "\x0d\x0a");
 687         if (wsi->c_origin) {
 688                 if (wsi->ietf_spec_revision == 13)
 689                         p += sprintf(p, "Origin: %s\x0d\x0a", wsi->c_origin);
 690                 else
 691                         p += sprintf(p, "Sec-WebSocket-Origin: %s\x0d\x0a",
 692                                                          wsi->c_origin);
 693         }
 694         if (wsi->c_protocol)
 695                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 696                                                        wsi->c_protocol);
 697
 698         /* tell the server what extensions we could support */
 699
 700         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 701 #ifndef LWS_NO_EXTENSIONS
 702         ext = context->extensions;
 703         while (ext && ext->callback) {
 704
 705                 n = 0;
 706                 ext1 = context->extensions;
 707
 708                 while (ext1 && ext1->callback) {
 709                         n |= ext1->callback(context, ext1, wsi,
 710                                 LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 711                                         NULL, (char *)ext->name, 0);
 712
 713                         ext1++;
 714                 }
 715
 716                 if (n) { /* an extension vetos us */
 717                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 718                         ext++;
 719                         continue;
 720                 }
 721
 722                 n = context->protocols[0].callback(context, wsi,
 723                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 724                                 wsi->user_space, (char *)ext->name, 0);
 725
 726                 /*
 727                  * zero return from callback means
 728                  * go ahead and allow the extension,
 729                  * it's what we get if the callback is
 730                  * unhandled
 731                  */
 732
 733                 if (n) {
 734                         ext++;
 735                         continue;
 736                 }
 737
 738                 /* apply it */
 739
 740                 if (ext_count)
 741                         *p++ = ',';
 742                 p += sprintf(p, "%s", ext->name);
 743                 ext_count++;
 744
 745                 ext++;
 746         }
 747 #endif
 748         p += sprintf(p, "\x0d\x0a");
 749
 750         if (wsi->ietf_spec_revision)
 751                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 752                                                wsi->ietf_spec_revision);
 753
 754         /* give userland a chance to append, eg, cookies */
 755
 756         context->protocols[0].callback(context, wsi,
 757                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 758                 NULL, &p, (pkt + sizeof(pkt)) - p - 12);
 759
 760         p += sprintf(p, "\x0d\x0a");
 761
 762         /* prepare the expected server accept response */
 763
 764         strcpy((char *)buf, key_b64);
 765         strcpy((char *)&buf[strlen((char *)buf)], magic_websocket_guid);
 766
 767         SHA1(buf, strlen((char *)buf), (unsigned char *)hash);
 768
 769         lws_b64_encode_string(hash, 20,
 770                         wsi->initial_handshake_hash_base64,
 771                              sizeof wsi->initial_handshake_hash_base64);
 772
 773         /* done with these now */
 774
 775         free(wsi->c_path);
 776         free(wsi->c_host);
 777         if (wsi->c_origin)
 778                 free(wsi->c_origin);
 779
 780         return p;
 781 }
 782