lib/handshake.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 /*
  25  * -04 of the protocol (actually the 80th version) has a radically different
  26  * handshake.  The 04 spec gives the following idea
  27  *
  28  *    The handshake from the client looks as follows:
  29  *
  30  *      GET /chat HTTP/1.1
  31  *      Host: server.example.com
  32  *      Upgrade: websocket
  33  *      Connection: Upgrade
  34  *      Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
  35  *      Sec-WebSocket-Origin: http://example.com
  36  *      Sec-WebSocket-Protocol: chat, superchat
  37  *      Sec-WebSocket-Version: 4
  38  *
  39  *  The handshake from the server looks as follows:
  40  *
  41  *       HTTP/1.1 101 Switching Protocols
  42  *       Upgrade: websocket
  43  *       Connection: Upgrade
  44  *       Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
  45  *       Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
  46  *       Sec-WebSocket-Protocol: chat
  47  */
  48
  49 /*
  50  * We have to take care about parsing because the headers may be split
  51  * into multiple fragments.  They may contain unknown headers with arbitrary
  52  * argument lengths.  So, we parse using a single-character at a time state
  53  * machine that is completely independent of packet size.
  54  */
  55
  56 LWS_VISIBLE int
  57 libwebsocket_read(struct libwebsocket_context *context,
  58                      struct libwebsocket *wsi, unsigned char *buf, size_t len)
  59 {
  60         size_t n;
  61 #ifndef LWS_NO_SERVER
  62         struct allocated_headers *ah;
  63         char *uri_ptr = NULL;
  64         int uri_len = 0;
  65         char content_length_str[32];
  66 #endif
  67
  68         switch (wsi->state) {
  69
  70         case WSI_STATE_HTTP_BODY:
  71 #ifndef LWS_NO_SERVER
  72 http_postbody:
  73 #endif
  74                 while (len--) {
  75
  76                         if (wsi->u.http.content_length_seen >= wsi->u.http.content_length)
  77                                 break;
  78
  79                         wsi->u.http.post_buffer[wsi->u.http.body_index++] = *buf++;
  80                         wsi->u.http.content_length_seen++;
  81                         n = wsi->protocol->rx_buffer_size;
  82                         if (!n)
  83                                 n = LWS_MAX_SOCKET_IO_BUF;
  84
  85                         if (wsi->u.http.body_index != n &&
  86                             wsi->u.http.content_length_seen != wsi->u.http.content_length)
  87                                 continue;
  88
  89                         if (wsi->protocol->callback) {
  90                                 n = wsi->protocol->callback(
  91                                         wsi->protocol->owning_server, wsi,
  92                                             LWS_CALLBACK_HTTP_BODY,
  93                                             wsi->user_space, wsi->u.http.post_buffer,
  94                                                         wsi->u.http.body_index);
  95                                 wsi->u.http.body_index = 0;
  96                                 if (n)
  97                                         goto bail;
  98                         }
  99
 100                         if (wsi->u.http.content_length_seen == wsi->u.http.content_length) {
 101                                 /* he sent the content in time */
 102                                 libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 103                                 n = wsi->protocol->callback(
 104                                         wsi->protocol->owning_server, wsi,
 105                                             LWS_CALLBACK_HTTP_BODY_COMPLETION,
 106                                             wsi->user_space, NULL, 0);
 107                                 wsi->u.http.body_index = 0;
 108                                 if (n)
 109                                         goto bail;
 110                         }
 111
 112                 }
 113
 114                 /*
 115                  * we need to spill here so everything is seen in the case
 116                  * there is no content-length
 117                  */
 118                 if (wsi->u.http.body_index && wsi->protocol->callback) {
 119                         n = wsi->protocol->callback(
 120                                 wsi->protocol->owning_server, wsi,
 121                                     LWS_CALLBACK_HTTP_BODY,
 122                                     wsi->user_space, wsi->u.http.post_buffer,
 123                                                 wsi->u.http.body_index);
 124                         wsi->u.http.body_index = 0;
 125                         if (n)
 126                                 goto bail;
 127                 }
 128                 break;
 129
 130         case WSI_STATE_HTTP_ISSUING_FILE:
 131         case WSI_STATE_HTTP:
 132                 wsi->state = WSI_STATE_HTTP_HEADERS;
 133                 wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 134                 wsi->u.hdr.lextable_pos = 0;
 135                 /* fallthru */
 136         case WSI_STATE_HTTP_HEADERS:
 137
 138                 lwsl_parser("issuing %d bytes to parser\n", (int)len);
 139
 140 #ifndef LWS_NO_CLIENT
 141                 switch (wsi->mode) {
 142                 case LWS_CONNMODE_WS_CLIENT_WAITING_PROXY_REPLY:
 143                 case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE:
 144                 case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 145                 case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 146                 case LWS_CONNMODE_WS_CLIENT:
 147                         for (n = 0; n < len; n++)
 148                                 if (libwebsocket_client_rx_sm(wsi, *buf++)) {
 149                                         lwsl_info("client_rx_sm failed\n");
 150                                         goto bail;
 151                                 }
 152                         return 0;
 153                 default:
 154                         break;
 155                 }
 156 #endif
 157 #ifndef LWS_NO_SERVER
 158                 /* LWS_CONNMODE_WS_SERVING */
 159
 160                 while (len--) {
 161                         if (libwebsocket_parse(wsi, *buf++)) {
 162                                 lwsl_info("libwebsocket_parse failed\n");
 163                                 goto bail_nuke_ah;
 164                         }
 165
 166                         if (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE)
 167                                 continue;
 168
 169                         lwsl_parser("libwebsocket_parse sees parsing complete\n");
 170
 171                         wsi->mode = LWS_CONNMODE_PRE_WS_SERVING_ACCEPT;
 172                         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 173
 174                         /* is this websocket protocol or normal http 1.0? */
 175
 176                         if (!lws_hdr_total_length(wsi, WSI_TOKEN_UPGRADE) ||
 177                                      !lws_hdr_total_length(wsi, WSI_TOKEN_CONNECTION)) {
 178
 179                                 /* it's not websocket.... shall we accept it as http? */
 180
 181                                 if (!lws_hdr_total_length(wsi, WSI_TOKEN_GET_URI) &&
 182                                     !lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI)) {
 183                                         lwsl_warn("Missing URI in HTTP request\n");
 184                                         goto bail_nuke_ah;
 185                                 }
 186
 187                                 if (lws_hdr_total_length(wsi, WSI_TOKEN_GET_URI) &&
 188                                     lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI)) {
 189                                         lwsl_warn("GET and POST methods?\n");
 190                                         goto bail_nuke_ah;
 191                                 }
 192
 193                                 if (libwebsocket_ensure_user_space(wsi))
 194                                         goto bail_nuke_ah;
 195
 196                                 if (lws_hdr_total_length(wsi, WSI_TOKEN_GET_URI)) {
 197                                         uri_ptr = lws_hdr_simple_ptr(wsi, WSI_TOKEN_GET_URI);
 198                                         uri_len = lws_hdr_total_length(wsi, WSI_TOKEN_GET_URI);
 199                                         lwsl_info("HTTP GET request for '%s'\n",
 200                                             lws_hdr_simple_ptr(wsi, WSI_TOKEN_GET_URI));
 201
 202                                 }
 203                                 if (lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI)) {
 204                                         lwsl_info("HTTP POST request for '%s'\n",
 205                                            lws_hdr_simple_ptr(wsi, WSI_TOKEN_POST_URI));
 206                                         uri_ptr = lws_hdr_simple_ptr(wsi, WSI_TOKEN_POST_URI);
 207                                         uri_len = lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI);
 208                                 }
 209
 210                                 /*
 211                                  * Hm we still need the headers so the
 212                                  * callback can look at leaders like the URI, but we
 213                                  * need to transition to http union state.... hold a
 214                                  * copy of u.hdr.ah and deallocate afterwards
 215                                  */
 216                                 ah = wsi->u.hdr.ah;
 217
 218                                 /* union transition */
 219                                 memset(&wsi->u, 0, sizeof(wsi->u));
 220                                 wsi->mode = LWS_CONNMODE_HTTP_SERVING_ACCEPTED;
 221                                 wsi->state = WSI_STATE_HTTP;
 222                                 wsi->u.http.fd = -1;
 223
 224                                 /* expose it at the same offset as u.hdr */
 225                                 wsi->u.http.ah = ah;
 226
 227                                 /* HTTP header had a content length? */
 228
 229                                 wsi->u.http.content_length = 0;
 230                                 if (lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI))
 231                                         wsi->u.http.content_length = 100 * 1024 * 1024;
 232
 233                                 if (lws_hdr_total_length(wsi, WSI_TOKEN_HTTP_CONTENT_LENGTH)) {
 234                                         lws_hdr_copy(wsi, content_length_str,
 235                                                         sizeof(content_length_str) - 1,
 236                                                                         WSI_TOKEN_HTTP_CONTENT_LENGTH);
 237                                         wsi->u.http.content_length = atoi(content_length_str);
 238                                 }
 239
 240                                 if (wsi->u.http.content_length > 0) {
 241                                         wsi->u.http.body_index = 0;
 242                                         n = wsi->protocol->rx_buffer_size;
 243                                         if (!n)
 244                                                 n = LWS_MAX_SOCKET_IO_BUF;
 245                                         wsi->u.http.post_buffer = malloc(n);
 246                                         if (!wsi->u.http.post_buffer) {
 247                                                 lwsl_err("Unable to allocate post buffer\n");
 248                                                 n = -1;
 249                                                 goto leave;
 250                                         }
 251                                 }
 252
 253                                 n = 0;
 254                                 if (wsi->protocol->callback)
 255                                         n = wsi->protocol->callback(context, wsi,
 256                                                 LWS_CALLBACK_FILTER_HTTP_CONNECTION,
 257                                                      wsi->user_space, uri_ptr, uri_len);
 258
 259                                 if (!n) {
 260                                         /*
 261                                          * if there is content supposed to be coming,
 262                                          * put a timeout on it having arrived
 263                                          */
 264                                         libwebsocket_set_timeout(wsi,
 265                                                 PENDING_TIMEOUT_HTTP_CONTENT,
 266                                                                       AWAITING_TIMEOUT);
 267
 268                                         if (wsi->protocol->callback)
 269                                                 n = wsi->protocol->callback(context, wsi,
 270                                                     LWS_CALLBACK_HTTP,
 271                                                     wsi->user_space, uri_ptr, uri_len);
 272                                 }
 273
 274 leave:
 275                                 /* now drop the header info we kept a pointer to */
 276                                 if (ah)
 277                                         free(ah);
 278                                 /* not possible to continue to use past here */
 279                                 wsi->u.http.ah = NULL;
 280
 281                                 if (n) {
 282                                         lwsl_info("LWS_CALLBACK_HTTP closing\n");
 283                                         goto bail; /* struct ah ptr already nuked */
 284                                 }
 285
 286                                 /*
 287                                  * (if callback didn't start sending a file)
 288                                  * deal with anything else as body, whether
 289                                  * there was a content-length or not
 290                                  */
 291
 292                                 if (wsi->state != WSI_STATE_HTTP_ISSUING_FILE)
 293                                         wsi->state = WSI_STATE_HTTP_BODY;
 294                                 goto http_postbody;
 295                         }
 296
 297                         if (!wsi->protocol)
 298                                 lwsl_err("NULL protocol at libwebsocket_read\n");
 299
 300                         /*
 301                          * It's websocket
 302                          *
 303                          * Make sure user side is happy about protocol
 304                          */
 305
 306                         while (wsi->protocol->callback) {
 307
 308                                 if (!lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL)) {
 309                                         if (wsi->protocol->name == NULL)
 310                                                 break;
 311                                 } else
 312                                         if (wsi->protocol->name && strcmp(
 313                                                 lws_hdr_simple_ptr(wsi,
 314                                                         WSI_TOKEN_PROTOCOL),
 315                                                               wsi->protocol->name) == 0)
 316                                                 break;
 317
 318                                 wsi->protocol++;
 319                         }
 320
 321                         /* we didn't find a protocol he wanted? */
 322
 323                         if (wsi->protocol->callback == NULL) {
 324                                 if (lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL) ==
 325                                                                                  NULL) {
 326                                         lwsl_info("no protocol -> prot 0 handler\n");
 327                                         wsi->protocol = &context->protocols[0];
 328                                 } else {
 329                                         lwsl_err("Req protocol %s not supported\n",
 330                                            lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL));
 331                                         goto bail_nuke_ah;
 332                                 }
 333                         }
 334
 335                         /* allocate wsi->user storage */
 336                         if (libwebsocket_ensure_user_space(wsi))
 337                                 goto bail_nuke_ah;
 338
 339                         /*
 340                          * Give the user code a chance to study the request and
 341                          * have the opportunity to deny it
 342                          */
 343
 344                         if ((wsi->protocol->callback)(wsi->protocol->owning_server, wsi,
 345                                         LWS_CALLBACK_FILTER_PROTOCOL_CONNECTION,
 346                                         wsi->user_space,
 347                                       lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL), 0)) {
 348                                 lwsl_warn("User code denied connection\n");
 349                                 goto bail_nuke_ah;
 350                         }
 351
 352
 353                         /*
 354                          * Perform the handshake according to the protocol version the
 355                          * client announced
 356                          */
 357
 358                         switch (wsi->ietf_spec_revision) {
 359                         case 13:
 360                                 lwsl_parser("lws_parse calling handshake_04\n");
 361                                 if (handshake_0405(context, wsi)) {
 362                                         lwsl_info("hs0405 has failed the connection\n");
 363                                         goto bail_nuke_ah;
 364                                 }
 365                                 break;
 366
 367                         default:
 368                                 lwsl_warn("Unknown client spec version %d\n",
 369                                                                wsi->ietf_spec_revision);
 370                                 goto bail_nuke_ah;
 371                         }
 372
 373                         /* drop the header info -- no bail_nuke_ah after this */
 374
 375                         if (wsi->u.hdr.ah)
 376                                 free(wsi->u.hdr.ah);
 377
 378                         wsi->mode = LWS_CONNMODE_WS_SERVING;
 379
 380                         /* union transition */
 381                         memset(&wsi->u, 0, sizeof(wsi->u));
 382                         wsi->u.ws.rxflow_change_to = LWS_RXFLOW_ALLOW;
 383
 384                         /*
 385                          * create the frame buffer for this connection according to the
 386                          * size mentioned in the protocol definition.  If 0 there, use
 387                          * a big default for compatibility
 388                          */
 389
 390                         n = wsi->protocol->rx_buffer_size;
 391                         if (!n)
 392                                 n = LWS_MAX_SOCKET_IO_BUF;
 393                         n += LWS_SEND_BUFFER_PRE_PADDING + LWS_SEND_BUFFER_POST_PADDING;
 394                         wsi->u.ws.rx_user_buffer = malloc(n);
 395                         if (!wsi->u.ws.rx_user_buffer) {
 396                                 lwsl_err("Out of Mem allocating rx buffer %d\n", n);
 397                                 goto bail;
 398                         }
 399                         lwsl_info("Allocating RX buffer %d\n", n);
 400
 401                         if (setsockopt(wsi->sock, SOL_SOCKET, SO_SNDBUF,  &n, sizeof n)) {
 402                                 lwsl_warn("Failed to set SNDBUF to %d", n);
 403                                 goto bail;
 404                         }
 405
 406                         lwsl_parser("accepted v%02d connection\n",
 407                                                                wsi->ietf_spec_revision);
 408                 } /* while all chars are handled */
 409                 break;
 410 #endif
 411
 412         case WSI_STATE_AWAITING_CLOSE_ACK:
 413         case WSI_STATE_ESTABLISHED:
 414 #ifndef LWS_NO_CLIENT
 415                 switch (wsi->mode) {
 416                 case LWS_CONNMODE_WS_CLIENT:
 417                         for (n = 0; n < len; n++)
 418                                 if (libwebsocket_client_rx_sm(
 419                                                              wsi, *buf++) < 0) {
 420                                         lwsl_info("client rx has bailed\n");
 421                                         goto bail;
 422                                 }
 423
 424                         return 0;
 425                 default:
 426                         break;
 427                 }
 428 #endif
 429 #ifndef LWS_NO_SERVER
 430                 /* LWS_CONNMODE_WS_SERVING */
 431
 432                 if (libwebsocket_interpret_incoming_packet(wsi, buf, len) < 0) {
 433                         lwsl_info("interpret_incoming_packet has bailed\n");
 434                         goto bail;
 435                 }
 436 #endif
 437                 break;
 438         default:
 439                 lwsl_err("libwebsocket_read: Unhandled state\n");
 440                 break;
 441         }
 442
 443         return 0;
 444
 445 #ifndef LWS_NO_SERVER
 446 bail_nuke_ah:
 447         /* drop the header info */
 448         if (wsi->u.hdr.ah)
 449                 free(wsi->u.hdr.ah);
 450 #endif
 451
 452 bail:
 453         lwsl_info("closing connection at libwebsocket_read bail:\n");
 454
 455         libwebsocket_close_and_free_session(context, wsi,
 456                                                      LWS_CLOSE_STATUS_NOSTATUS);
 457
 458         return -1;
 459 }