/* * libwebsockets - small server side websockets and web server implementation * * Copyright (C) 2010-2013 Andy Green * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation: * version 2.1 of the License. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, * MA 02110-1301 USA */ #include "private-libwebsockets.h" /* * -04 of the protocol (actually the 80th version) has a radically different * handshake. The 04 spec gives the following idea * * The handshake from the client looks as follows: * * GET /chat HTTP/1.1 * Host: server.example.com * Upgrade: websocket * Connection: Upgrade * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ== * Sec-WebSocket-Origin: http://example.com * Sec-WebSocket-Protocol: chat, superchat * Sec-WebSocket-Version: 4 * * The handshake from the server looks as follows: * * HTTP/1.1 101 Switching Protocols * Upgrade: websocket * Connection: Upgrade * Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo= * Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC== * Sec-WebSocket-Protocol: chat */ /* * We have to take care about parsing because the headers may be split * into multiple fragments. They may contain unknown headers with arbitrary * argument lengths. So, we parse using a single-character at a time state * machine that is completely independent of packet size. */ int libwebsocket_read(struct libwebsocket_context *context, struct libwebsocket *wsi, unsigned char * buf, size_t len) { size_t n; switch (wsi->state) { case WSI_STATE_HTTP_ISSUING_FILE: case WSI_STATE_HTTP: wsi->state = WSI_STATE_HTTP_HEADERS; wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART; wsi->u.hdr.lextable_pos = 0; /* fallthru */ case WSI_STATE_HTTP_HEADERS: lwsl_parser("issuing %d bytes to parser\n", (int)len); #ifdef _DEBUG //fwrite(buf, 1, len, stderr); #endif #ifndef LWS_NO_CLIENT // lwsl_info("mode=%d\n", wsi->mode); switch (wsi->mode) { case LWS_CONNMODE_WS_CLIENT_WAITING_PROXY_REPLY: case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE: case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY: case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT: case LWS_CONNMODE_WS_CLIENT: for (n = 0; n < len; n++) libwebsocket_client_rx_sm(wsi, *buf++); return 0; default: break; } #endif #ifndef LWS_NO_SERVER /* LWS_CONNMODE_WS_SERVING */ extern int handshake_0405(struct libwebsocket_context *context, struct libwebsocket *wsi); for (n = 0; n < len; n++) libwebsocket_parse(wsi, *buf++); if (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE) break; lwsl_parser("seem to be serving, mode is %d\n", wsi->mode); lwsl_parser("libwebsocket_parse sees parsing complete\n"); /* is this websocket protocol or normal http 1.0? */ if (!wsi->utf8_token[WSI_TOKEN_UPGRADE].token_len || !wsi->utf8_token[WSI_TOKEN_CONNECTION].token_len) { wsi->state = WSI_STATE_HTTP; if (wsi->protocol->callback) if (wsi->protocol->callback(context, wsi, LWS_CALLBACK_HTTP, wsi->user_space, wsi->utf8_token[WSI_TOKEN_GET_URI].token, wsi->utf8_token[WSI_TOKEN_GET_URI].token_len)) { lwsl_info("LWS_CALLBACK_HTTP wanted to close\n"); goto bail; } return 0; } if (!wsi->protocol) lwsl_err("NULL protocol at libwebsocket_read\n"); /* * It's websocket * * Make sure user side is happy about protocol */ while (wsi->protocol->callback) { if (wsi->utf8_token[WSI_TOKEN_PROTOCOL].token == NULL) { if (wsi->protocol->name == NULL) break; } else if (wsi->protocol->name && strcmp( wsi->utf8_token[WSI_TOKEN_PROTOCOL].token, wsi->protocol->name) == 0) break; wsi->protocol++; } /* we didn't find a protocol he wanted? */ if (wsi->protocol->callback == NULL) { if (wsi->utf8_token[WSI_TOKEN_PROTOCOL].token == NULL) { lwsl_info("[no protocol] " "mapped to protocol 0 handler\n"); wsi->protocol = &context->protocols[0]; } else { lwsl_err("Requested protocol %s " "not supported\n", wsi->utf8_token[WSI_TOKEN_PROTOCOL].token); goto bail; } } /* * find out which spec version the client is using * if this header is not given, we default to 00 (aka 76) */ if (wsi->utf8_token[WSI_TOKEN_VERSION].token_len) wsi->ietf_spec_revision = atoi(wsi->utf8_token[WSI_TOKEN_VERSION].token); /* * Give the user code a chance to study the request and * have the opportunity to deny it */ if ((wsi->protocol->callback)(wsi->protocol->owning_server, wsi, LWS_CALLBACK_FILTER_PROTOCOL_CONNECTION, &wsi->utf8_token[0], NULL, 0)) { lwsl_warn("User code denied connection\n"); goto bail; } /* * Perform the handshake according to the protocol version the * client announced */ switch (wsi->ietf_spec_revision) { case 13: lwsl_parser("libwebsocket_parse calling handshake_04\n"); if (handshake_0405(context, wsi)) { lwsl_info("handshake_0405 xor 05 has failed the connection\n"); goto bail; } break; default: lwsl_warn("Unknown client spec version %d\n", wsi->ietf_spec_revision); goto bail; } wsi->mode = LWS_CONNMODE_WS_SERVING; /* union transition */ memset(&wsi->u, 0, sizeof wsi->u); lwsl_parser("accepted v%02d connection\n", wsi->ietf_spec_revision); #endif break; case WSI_STATE_AWAITING_CLOSE_ACK: case WSI_STATE_ESTABLISHED: #ifndef LWS_NO_CLIENT switch (wsi->mode) { case LWS_CONNMODE_WS_CLIENT: for (n = 0; n < len; n++) if (libwebsocket_client_rx_sm(wsi, *buf++) < 0) { lwsl_info("client rx has bailed\n"); goto bail; } return 0; default: break; } #endif #ifndef LWS_NO_SERVER /* LWS_CONNMODE_WS_SERVING */ if (libwebsocket_interpret_incoming_packet(wsi, buf, len) < 0) { lwsl_info("interpret_incoming_packet has bailed\n"); goto bail; } #endif break; default: lwsl_err("libwebsocket_read: Unhandled state\n"); break; } return 0; bail: lwsl_info("closing connection at libwebsocket_read bail:\n"); libwebsocket_close_and_free_session(context, wsi, LWS_CLOSE_STATUS_NOSTATUS); return -1; }