/* * libwebsockets - small server side websockets and web server implementation * * Copyright (C) 2010 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" const struct lws_tokens lws_tokens[WSI_TOKEN_COUNT] = { { "GET ", 4 }, { "Host:", 5 }, { "Connection:", 11 }, { "Sec-WebSocket-Key1:", 19 }, { "Sec-WebSocket-Key2:", 19 }, { "Sec-WebSocket-Protocol:", 23 }, { "Upgrade:", 8 }, { "Origin:", 7 }, { "Sec-WebSocket-Draft:", 20 }, { "\x0d\x0a", 2 }, }; int libwebsocket_parse(struct libwebsocket *wsi, unsigned char c) { int n; switch (wsi->parser_state) { case WSI_TOKEN_GET_URI: case WSI_TOKEN_HOST: case WSI_TOKEN_CONNECTION: case WSI_TOKEN_KEY1: case WSI_TOKEN_KEY2: case WSI_TOKEN_PROTOCOL: case WSI_TOKEN_UPGRADE: case WSI_TOKEN_ORIGIN: case WSI_TOKEN_DRAFT: case WSI_TOKEN_CHALLENGE: debug("WSI_TOKEN_(%d) '%c'\n", wsi->parser_state, c); /* collect into malloc'd buffers */ /* optional space swallow */ if (!wsi->utf8_token[wsi->parser_state].token_len && c == ' ') break; /* special case space terminator for get-uri */ if (wsi->parser_state == WSI_TOKEN_GET_URI && c == ' ') { wsi->utf8_token[wsi->parser_state].token[ wsi->utf8_token[wsi->parser_state].token_len] = '\0'; wsi->parser_state = WSI_TOKEN_SKIPPING; break; } /* allocate appropriate memory */ if (wsi->utf8_token[wsi->parser_state].token_len == wsi->current_alloc_len - 1) { /* need to extend */ wsi->current_alloc_len += LWS_ADDITIONAL_HDR_ALLOC; if (wsi->current_alloc_len >= LWS_MAX_HEADER_LEN) { /* it's waaay to much payload, fail it */ strcpy(wsi->utf8_token[wsi->parser_state].token, "!!! Length exceeded maximum supported !!!"); wsi->parser_state = WSI_TOKEN_SKIPPING; break; } wsi->utf8_token[wsi->parser_state].token = realloc(wsi->utf8_token[wsi->parser_state].token, wsi->current_alloc_len); } /* bail at EOL */ if (wsi->parser_state != WSI_TOKEN_CHALLENGE && c == '\x0d') { wsi->utf8_token[wsi->parser_state].token[ wsi->utf8_token[wsi->parser_state].token_len] = '\0'; wsi->parser_state = WSI_TOKEN_SKIPPING_SAW_CR; break; } wsi->utf8_token[wsi->parser_state].token[ wsi->utf8_token[wsi->parser_state].token_len++] = c; /* special payload limiting */ if (wsi->parser_state == WSI_TOKEN_CHALLENGE && wsi->utf8_token[wsi->parser_state].token_len == 8) { debug("Setting WSI_PARSING_COMPLETE\n"); wsi->parser_state = WSI_PARSING_COMPLETE; break; } break; /* collecting and checking a name part */ case WSI_TOKEN_NAME_PART: debug("WSI_TOKEN_NAME_PART '%c'\n", c); if (wsi->name_buffer_pos == sizeof(wsi->name_buffer) - 1) { /* name bigger than we can handle, skip until next */ wsi->parser_state = WSI_TOKEN_SKIPPING; break; } wsi->name_buffer[wsi->name_buffer_pos++] = c; wsi->name_buffer[wsi->name_buffer_pos] = '\0'; for (n = 0; n < WSI_TOKEN_COUNT; n++) { if (wsi->name_buffer_pos != lws_tokens[n].token_len) continue; if (strcmp(lws_tokens[n].token, wsi->name_buffer)) continue; debug("known hdr '%s'\n", wsi->name_buffer); wsi->parser_state = WSI_TOKEN_GET_URI + n; wsi->current_alloc_len = LWS_INITIAL_HDR_ALLOC; wsi->utf8_token[wsi->parser_state].token = malloc(wsi->current_alloc_len); wsi->utf8_token[wsi->parser_state].token_len = 0; n = WSI_TOKEN_COUNT; } /* colon delimiter means we just don't know this name */ if (wsi->parser_state == WSI_TOKEN_NAME_PART && c == ':') { debug("skipping unknown header '%s'\n", wsi->name_buffer); wsi->parser_state = WSI_TOKEN_SKIPPING; break; } /* don't look for payload when it can just be http headers */ if (wsi->parser_state == WSI_TOKEN_CHALLENGE && !wsi->utf8_token[WSI_TOKEN_UPGRADE].token_len) { /* they're HTTP headers, not websocket upgrade! */ debug("Setting WSI_PARSING_COMPLETE " "from http headers\n"); wsi->parser_state = WSI_PARSING_COMPLETE; } break; /* skipping arg part of a name we didn't recognize */ case WSI_TOKEN_SKIPPING: debug("WSI_TOKEN_SKIPPING '%c'\n", c); if (c == '\x0d') wsi->parser_state = WSI_TOKEN_SKIPPING_SAW_CR; break; case WSI_TOKEN_SKIPPING_SAW_CR: debug("WSI_TOKEN_SKIPPING_SAW_CR '%c'\n", c); if (c == '\x0a') wsi->parser_state = WSI_TOKEN_NAME_PART; else wsi->parser_state = WSI_TOKEN_SKIPPING; wsi->name_buffer_pos = 0; break; /* we're done, ignore anything else */ case WSI_PARSING_COMPLETE: debug("WSI_PARSING_COMPLETE '%c'\n", c); break; default: /* keep gcc happy */ break; } return 0; } static int libwebsocket_rx_sm(struct libwebsocket *wsi, unsigned char c) { int n; unsigned char buf[2]; switch (wsi->lws_rx_parse_state) { case LWS_RXPS_NEW: switch (wsi->ietf_spec_revision) { /* Firefox 4.0b6 likes this as of 30 Oct */ case 76: if (c == 0xff) wsi->lws_rx_parse_state = LWS_RXPS_SEEN_76_FF; break; case 0: break; } if (c == 0) { wsi->lws_rx_parse_state = LWS_RXPS_EAT_UNTIL_76_FF; wsi->rx_user_buffer_head = 0; } break; case LWS_RXPS_EAT_UNTIL_76_FF: if (c == 0xff) { wsi->lws_rx_parse_state = LWS_RXPS_NEW; goto issue; } wsi->rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING + (wsi->rx_user_buffer_head++)] = c; if (wsi->rx_user_buffer_head != MAX_USER_RX_BUFFER) break; issue: if (wsi->protocol->callback) wsi->protocol->callback(wsi, LWS_CALLBACK_RECEIVE, wsi->user_space, &wsi->rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING], wsi->rx_user_buffer_head); wsi->rx_user_buffer_head = 0; break; case LWS_RXPS_SEEN_76_FF: if (c) break; debug("Seen that client is requesting " "a v76 close, sending ack\n"); buf[0] = 0xff; buf[1] = 0; n = libwebsocket_write(wsi, buf, 2, LWS_WRITE_HTTP); if (n < 0) { fprintf(stderr, "ERROR writing to socket"); return -1; } debug(" v76 close ack sent, server closing skt\n"); /* returning < 0 will get it closed in parent */ return -1; case LWS_RXPS_PULLING_76_LENGTH: break; case LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED: break; } return 0; } int libwebsocket_interpret_incoming_packet(struct libwebsocket *wsi, unsigned char *buf, size_t len) { int n; #ifdef DEBUG fprintf(stderr, "received %d byte packet\n", (int)len); for (n = 0; n < len; n++) fprintf(stderr, "%02X ", buf[n]); fprintf(stderr, "\n"); #endif /* let the rx protocol state machine have as much as it needs */ n = 0; while (wsi->lws_rx_parse_state != LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED && n < len) if (libwebsocket_rx_sm(wsi, buf[n++]) < 0) return -1; return -0; } /** * libwebsocket_write() - Apply protocol then write data to client * @wsi: Websocket instance (available from user callback) * @buf: The data to send. For data being sent on a websocket * connection (ie, not default http), this buffer MUST have * LWS_SEND_BUFFER_PRE_PADDING bytes valid BEFORE the pointer * and an additional LWS_SEND_BUFFER_POST_PADDING bytes valid * in the buffer after (buf + len). This is so the protocol * header and trailer data can be added in-situ. * @len: Count of the data bytes in the payload starting from buf * @protocol: Use LWS_WRITE_HTTP to reply to an http connection, and one * of LWS_WRITE_BINARY or LWS_WRITE_TEXT to send appropriate * data on a websockets connection. Remember to allow the extra * bytes before and after buf if LWS_WRITE_BINARY or LWS_WRITE_TEXT * are used. * * This function provides the way to issue data back to the client * for both http and websocket protocols. * * In the case of sending using websocket protocol, be sure to allocate * valid storage before and after buf as explained above. This scheme * allows maximum efficiency of sending data and protocol in a single * packet while not burdening the user code with any protocol knowledge. */ int libwebsocket_write(struct libwebsocket *wsi, unsigned char *buf, size_t len, enum libwebsocket_write_protocol protocol) { int n; int pre = 0; int post = 0; unsigned int shift = 7; if (protocol == LWS_WRITE_HTTP) goto send_raw; /* websocket protocol, either binary or text */ if (wsi->state != WSI_STATE_ESTABLISHED) return -1; switch (wsi->ietf_spec_revision) { /* chrome likes this as of 30 Oct */ /* Firefox 4.0b6 likes this as of 30 Oct */ case 76: if (protocol == LWS_WRITE_BINARY) { /* in binary mode we send 7-bit used length blocks */ pre = 1; while (len & (127 << shift)) { pre++; shift += 7; } n = 0; shift -= 7; while (shift >= 0) { if (shift) buf[0 - pre + n] = ((len >> shift) & 127) | 0x80; else buf[0 - pre + n] = ((len >> shift) & 127); n++; shift -= 7; } break; } /* frame type = text, length-free spam mode */ buf[-1] = 0; buf[len] = 0xff; /* EOT marker */ pre = 1; post = 1; break; case 0: buf[-9] = 0xff; #if defined __LP64__ buf[-8] = len >> 56; buf[-7] = len >> 48; buf[-6] = len >> 40; buf[-5] = len >> 32; #else buf[-8] = 0; buf[-7] = 0; buf[-6] = 0; buf[-5] = 0; #endif buf[-4] = len >> 24; buf[-3] = len >> 16; buf[-2] = len >> 8; buf[-1] = len; pre = 9; break; /* just an unimplemented spec right now apparently */ case 2: n = 4; /* text */ if (protocol == LWS_WRITE_BINARY) n = 5; /* binary */ if (len < 126) { buf[-2] = n; buf[-1] = len; pre = 2; } else { if (len < 65536) { buf[-4] = n; buf[-3] = 126; buf[-2] = len >> 8; buf[-1] = len; pre = 4; } else { buf[-10] = n; buf[-9] = 127; #if defined __LP64__ buf[-8] = (len >> 56) & 0x7f; buf[-7] = len >> 48; buf[-6] = len >> 40; buf[-5] = len >> 32; #else buf[-8] = 0; buf[-7] = 0; buf[-6] = 0; buf[-5] = 0; #endif buf[-4] = len >> 24; buf[-3] = len >> 16; buf[-2] = len >> 8; buf[-1] = len; pre = 10; } } break; } #if 0 for (n = 0; n < (len + pre + post); n++) fprintf(stderr, "%02X ", buf[n - pre]); fprintf(stderr, "\n"); #endif send_raw: #ifdef LWS_OPENSSL_SUPPORT if (use_ssl) { n = SSL_write(wsi->ssl, buf - pre, len + pre + post); if (n < 0) { fprintf(stderr, "ERROR writing to socket"); return -1; } } else { #endif n = send(wsi->sock, buf - pre, len + pre + post, 0); if (n < 0) { fprintf(stderr, "ERROR writing to socket"); return -1; } #ifdef LWS_OPENSSL_SUPPORT } #endif debug("written %d bytes to client\n", (int)len); return 0; } /** * libwebsockets_serve_http_file() - Send a file back to the client using http * @wsi: Websocket instance (available from user callback) * @file: The file to issue over http * @content_type: The http content type, eg, text/html * * This function is intended to be called from the callback in response * to http requests from the client. It allows the callback to issue * local files down the http link in a single step. */ int libwebsockets_serve_http_file(struct libwebsocket *wsi, const char *file, const char *content_type) { int fd; struct stat stat; char buf[512]; char *p = buf; int n; fd = open(file, O_RDONLY); if (fd < 1) { p += sprintf(p, "HTTP/1.0 400 Bad\x0d\x0a" "Server: libwebsockets\x0d\x0a" "\x0d\x0a" ); libwebsocket_write(wsi, (unsigned char *)buf, p - buf, LWS_WRITE_HTTP); return -1; } fstat(fd, &stat); p += sprintf(p, "HTTP/1.0 200 OK\x0d\x0a" "Server: libwebsockets\x0d\x0a" "Content-Type: %s\x0d\x0a" "Content-Length: %u\x0d\x0a" "\x0d\x0a", content_type, (unsigned int)stat.st_size); libwebsocket_write(wsi, (unsigned char *)buf, p - buf, LWS_WRITE_HTTP); n = 1; while (n > 0) { n = read(fd, buf, 512); libwebsocket_write(wsi, (unsigned char *)buf, n, LWS_WRITE_HTTP); } close(fd); return 0; }