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
  62         switch (wsi->state) {
  63
  64         case WSI_STATE_HTTP_BODY:
  65 http_postbody:
  66                 while (len--) {
  67
  68                         if (wsi->u.http.content_length_seen >= wsi->u.http.content_length)
  69                                 break;
  70
  71                         wsi->u.http.post_buffer[wsi->u.http.body_index++] = *buf++;
  72                         wsi->u.http.content_length_seen++;
  73                         n = wsi->protocol->rx_buffer_size;
  74                         if (!n)
  75                                 n = LWS_MAX_SOCKET_IO_BUF;
  76
  77                         if (wsi->u.http.body_index != n &&
  78                             wsi->u.http.content_length_seen != wsi->u.http.content_length)
  79                                 continue;
  80
  81                         if (wsi->protocol->callback) {
  82                                 n = wsi->protocol->callback(
  83                                         wsi->protocol->owning_server, wsi,
  84                                             LWS_CALLBACK_HTTP_BODY,
  85                                             wsi->user_space, wsi->u.http.post_buffer,
  86                                                         wsi->u.http.body_index);
  87                                 wsi->u.http.body_index = 0;
  88                                 if (n)
  89                                         goto bail;
  90                         }
  91
  92                         if (wsi->u.http.content_length_seen == wsi->u.http.content_length) {
  93                                 /* he sent the content in time */
  94                                 libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
  95                                 n = wsi->protocol->callback(
  96                                         wsi->protocol->owning_server, wsi,
  97                                             LWS_CALLBACK_HTTP_BODY_COMPLETION,
  98                                             wsi->user_space, NULL, 0);
  99                                 wsi->u.http.body_index = 0;
 100                                 if (n)
 101                                         goto bail;
 102                         }
 103
 104                 }
 105
 106                 /*
 107                  * we need to spill here so everything is seen in the case
 108                  * there is no content-length
 109                  */
 110                 if (wsi->u.http.body_index && wsi->protocol->callback) {
 111                         n = wsi->protocol->callback(
 112                                 wsi->protocol->owning_server, wsi,
 113                                     LWS_CALLBACK_HTTP_BODY,
 114                                     wsi->user_space, wsi->u.http.post_buffer,
 115                                                 wsi->u.http.body_index);
 116                         wsi->u.http.body_index = 0;
 117                         if (n)
 118                                 goto bail;
 119                 }
 120                 break;
 121
 122         case WSI_STATE_HTTP_ISSUING_FILE:
 123         case WSI_STATE_HTTP:
 124                 wsi->state = WSI_STATE_HTTP_HEADERS;
 125                 wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 126                 wsi->u.hdr.lextable_pos = 0;
 127                 /* fallthru */
 128         case WSI_STATE_HTTP_HEADERS:
 129
 130                 lwsl_parser("issuing %d bytes to parser\n", (int)len);
 131
 132                 if (lws_handshake_client(wsi, &buf, len))
 133                         goto bail;
 134
 135                 switch (lws_handshake_server(context, wsi, &buf, len)) {
 136                 case 1:
 137                         goto bail;
 138                 case 2:
 139                         goto http_postbody;
 140                 }
 141                 break;
 142
 143         case WSI_STATE_AWAITING_CLOSE_ACK:
 144         case WSI_STATE_ESTABLISHED:
 145 #ifndef LWS_NO_CLIENT
 146                 switch (wsi->mode) {
 147                 case LWS_CONNMODE_WS_CLIENT:
 148                         for (n = 0; n < len; n++)
 149                                 if (libwebsocket_client_rx_sm(
 150                                                              wsi, *buf++)) {
 151                                         lwsl_debug("client rx has bailed\n");
 152                                         goto bail;
 153                                 }
 154
 155                         return 0;
 156                 default:
 157                         break;
 158                 }
 159 #endif
 160 #ifndef LWS_NO_SERVER
 161                 /* LWS_CONNMODE_WS_SERVING */
 162
 163                 if (libwebsocket_interpret_incoming_packet(wsi, buf, len) < 0) {
 164                         lwsl_info("interpret_incoming_packet has bailed\n");
 165                         goto bail;
 166                 }
 167 #endif
 168                 break;
 169         default:
 170                 lwsl_err("libwebsocket_read: Unhandled state\n");
 171                 break;
 172         }
 173
 174         return 0;
 175
 176 bail:
 177         lwsl_debug("closing connection at libwebsocket_read bail:\n");
 178
 179         libwebsocket_close_and_free_session(context, wsi,
 180                                                      LWS_CLOSE_STATUS_NOSTATUS);
 181
 182         return -1;
 183 }