2 * libwebsockets - small server side websockets and web server implementation
4 * Copyright (C) 2010-2015 Andy Green <andy@warmcat.com>
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.
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.
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,
22 #include "private-libwebsockets.h"
25 * -04 of the protocol (actually the 80th version) has a radically different
26 * handshake. The 04 spec gives the following idea
28 * The handshake from the client looks as follows:
31 * Host: server.example.com
34 * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
35 * Sec-WebSocket-Origin: http://example.com
36 * Sec-WebSocket-Protocol: chat, superchat
37 * Sec-WebSocket-Version: 4
39 * The handshake from the server looks as follows:
41 * HTTP/1.1 101 Switching Protocols
44 * Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
45 * Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
46 * Sec-WebSocket-Protocol: chat
50 #define min(a, b) ((a) < (b) ? (a) : (b))
54 * We have to take care about parsing because the headers may be split
55 * into multiple fragments. They may contain unknown headers with arbitrary
56 * argument lengths. So, we parse using a single-character at a time state
57 * machine that is completely independent of packet size.
59 * Returns <0 for error or length of chars consumed from buf (up to len)
63 lws_read(struct lws *wsi, unsigned char *buf, size_t len)
65 unsigned char *last_char, *oldbuf = buf;
69 lwsl_debug("%s: incoming len %d state %d\n", __func__, (int)len, wsi->state);
73 case LWSS_HTTP2_AWAIT_CLIENT_PREFACE:
74 case LWSS_HTTP2_ESTABLISHED_PRE_SETTINGS:
75 case LWSS_HTTP2_ESTABLISHED:
79 * we were accepting input but now we stopped doing so
81 if (!(wsi->rxflow_change_to & LWS_RXFLOW_ALLOW)) {
82 lws_rxflow_cache(wsi, buf, n, len);
87 /* account for what we're using in rxflow buffer */
88 if (wsi->rxflow_buffer)
90 if (lws_http2_parser(wsi, buf[n++])) {
91 lwsl_debug("%s: http2_parser bailed\n", __func__);
98 case LWSS_CLIENT_HTTP_ESTABLISHED:
102 wsi->hdr_parsing_completed = 0;
104 case LWSS_HTTP_ISSUING_FILE:
105 wsi->state = LWSS_HTTP_HEADERS;
106 wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
107 wsi->u.hdr.lextable_pos = 0;
109 case LWSS_HTTP_HEADERS:
110 if (!wsi->u.hdr.ah) {
111 lwsl_err("%s: LWSS_HTTP_HEADERS: NULL ah\n", __func__);
114 lwsl_parser("issuing %d bytes to parser\n", (int)len);
116 if (lws_handshake_client(wsi, &buf, len))
120 if (lws_handshake_server(wsi, &buf, len))
121 /* Handshake indicates this session is done. */
125 * It's possible that we've exhausted our data already, or
126 * rx flow control has stopped us dealing with this early,
127 * but lws_handshake_server doesn't update len for us.
128 * Figure out how much was read, so that we can proceed
131 len -= (buf - last_char);
132 lwsl_debug("%s: thinks we have used %d\n", __func__, len);
134 if (!wsi->hdr_parsing_completed)
135 /* More header content on the way */
138 switch (wsi->state) {
140 case LWSS_HTTP_HEADERS:
142 case LWSS_HTTP_ISSUING_FILE:
145 wsi->u.http.content_remain =
146 wsi->u.http.content_length;
147 if (wsi->u.http.content_remain)
150 /* there is no POST content */
151 goto postbody_completion;
159 while (len && wsi->u.http.content_remain) {
160 /* Copy as much as possible, up to the limit of:
161 * what we have in the read buffer (len)
162 * remaining portion of the POST body (content_remain)
164 body_chunk_len = min(wsi->u.http.content_remain,len);
165 wsi->u.http.content_remain -= body_chunk_len;
166 len -= body_chunk_len;
169 struct lws_cgi_args args;
172 args.stdwsi = &wsi->cgi->stdwsi[0];
174 args.len = body_chunk_len;
176 /* returns how much used */
177 n = user_callback_handle_rxflow(
178 wsi->protocol->callback,
179 wsi, LWS_CALLBACK_CGI_STDIN_DATA,
186 n = wsi->protocol->callback(wsi,
187 LWS_CALLBACK_HTTP_BODY, wsi->user_space,
188 buf, body_chunk_len);
197 if (wsi->u.http.content_remain) {
198 lws_set_timeout(wsi, PENDING_TIMEOUT_HTTP_CONTENT,
199 wsi->context->timeout_secs);
202 /* he sent all the content in time */
204 lws_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
209 n = wsi->protocol->callback(wsi,
210 LWS_CALLBACK_HTTP_BODY_COMPLETION,
211 wsi->user_space, NULL, 0);
220 case LWSS_ESTABLISHED:
221 case LWSS_AWAITING_CLOSE_ACK:
223 if (lws_handshake_client(wsi, &buf, len))
226 case LWSCM_WS_SERVING:
228 if (lws_interpret_incoming_packet(wsi, &buf, len) < 0) {
229 lwsl_info("interpret_incoming_packet has bailed\n");
236 lwsl_err("%s: Unhandled state %d\n", __func__, wsi->state);
241 /* Nothing more to do for now */
242 lwsl_info("%s: read_ok, used %d\n", __func__, buf - oldbuf);
247 lwsl_debug("closing connection at lws_read bail:\n");
248 lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);