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