/* * 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" #ifdef WIN32 #include #endif int libwebsocket_client_rx_sm(struct libwebsocket *wsi, unsigned char c) { int n; unsigned char buf[20 + 4]; int callback_action = LWS_CALLBACK_CLIENT_RECEIVE; int handled; struct lws_tokens eff_buf; int m; // lwsl_parser(" CRX: %02X %d\n", c, wsi->lws_rx_parse_state); 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 0: if (c == 0xff) wsi->lws_rx_parse_state = LWS_RXPS_SEEN_76_FF; if (c == 0) { wsi->lws_rx_parse_state = LWS_RXPS_EAT_UNTIL_76_FF; wsi->rx_user_buffer_head = 0; } break; case 4: case 5: case 6: case 7: case 8: case 13: /* * 04 logical framing from the spec (all this is masked when * incoming and has to be unmasked) * * We ignore the possibility of extension data because we don't * negotiate any extensions at the moment. * * 0 1 2 3 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-------+-+-------------+-------------------------------+ * |F|R|R|R| opcode|R| Payload len | Extended payload length | * |I|S|S|S| (4) |S| (7) | (16/63) | * |N|V|V|V| |V| | (if payload len==126/127) | * | |1|2|3| |4| | | * +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - + * | Extended payload length continued, if payload len == 127 | * + - - - - - - - - - - - - - - - +-------------------------------+ * | | Extension data | * +-------------------------------+ - - - - - - - - - - - - - - - + * : : * +---------------------------------------------------------------+ * : Application data : * +---------------------------------------------------------------+ * * We pass payload through to userland as soon as we get it, ignoring * FIN. It's up to userland to buffer it up if it wants to see a * whole unfragmented block of the original size (which may be up to * 2^63 long!) * * Notice in v7 RSV4 is set to indicate 32-bit frame key is coming in * after length, unlike extension data which is now deprecated, this * does not impact the payload length calculation. */ /* * 04 spec defines the opcode like this: (1, 2, and 3 are * "control frame" opcodes which may not be fragmented or * have size larger than 126) * * frame-opcode = * %x0 ; continuation frame * / %x1 ; connection close * / %x2 ; ping * / %x3 ; pong * / %x4 ; text frame * / %x5 ; binary frame * / %x6-F ; reserved * * FIN (b7) */ if (wsi->ietf_spec_revision < 7) switch (c & 0xf) { case LWS_WS_OPCODE_04__CONTINUATION: wsi->opcode = LWS_WS_OPCODE_07__CONTINUATION; break; case LWS_WS_OPCODE_04__CLOSE: wsi->opcode = LWS_WS_OPCODE_07__CLOSE; break; case LWS_WS_OPCODE_04__PING: wsi->opcode = LWS_WS_OPCODE_07__PING; break; case LWS_WS_OPCODE_04__PONG: wsi->opcode = LWS_WS_OPCODE_07__PONG; break; case LWS_WS_OPCODE_04__TEXT_FRAME: wsi->opcode = LWS_WS_OPCODE_07__TEXT_FRAME; break; case LWS_WS_OPCODE_04__BINARY_FRAME: wsi->opcode = LWS_WS_OPCODE_07__BINARY_FRAME; break; default: lwsl_warn("reserved opcodes not " "usable pre v7 protocol\n"); return -1; } else wsi->opcode = c & 0xf; wsi->rsv = (c & 0x70); wsi->final = !!((c >> 7) & 1); wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN; break; default: lwsl_err("client_rx_sm doesn't know how " "to handle spec version %02d\n", wsi->ietf_spec_revision); break; } break; case LWS_RXPS_04_FRAME_HDR_LEN: if ((c & 0x80) && wsi->ietf_spec_revision < 7) { lwsl_warn("Frame has extensions set illegally 4\n"); /* kill the connection */ return -1; } wsi->this_frame_masked = !!(c & 0x80); switch (c & 0x7f) { case 126: /* control frames are not allowed to have big lengths */ if (wsi->opcode & 8) goto illegal_ctl_length; wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_2; break; case 127: /* control frames are not allowed to have big lengths */ if (wsi->opcode & 8) goto illegal_ctl_length; wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_8; break; default: wsi->rx_packet_length = c; if (wsi->this_frame_masked) wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_1; else { if (c) wsi->lws_rx_parse_state = LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED; else { wsi->lws_rx_parse_state = LWS_RXPS_NEW; goto spill; } } break; } break; case LWS_RXPS_04_FRAME_HDR_LEN16_2: wsi->rx_packet_length = c << 8; wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_1; break; case LWS_RXPS_04_FRAME_HDR_LEN16_1: wsi->rx_packet_length |= c; if (wsi->this_frame_masked) wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_1; else { if (wsi->rx_packet_length) wsi->lws_rx_parse_state = LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED; else { wsi->lws_rx_parse_state = LWS_RXPS_NEW; goto spill; } } break; case LWS_RXPS_04_FRAME_HDR_LEN64_8: if (c & 0x80) { lwsl_warn("b63 of length must be zero\n"); /* kill the connection */ return -1; } #if defined __LP64__ wsi->rx_packet_length = ((size_t)c) << 56; #else wsi->rx_packet_length = 0; #endif wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_7; break; case LWS_RXPS_04_FRAME_HDR_LEN64_7: #if defined __LP64__ wsi->rx_packet_length |= ((size_t)c) << 48; #endif wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_6; break; case LWS_RXPS_04_FRAME_HDR_LEN64_6: #if defined __LP64__ wsi->rx_packet_length |= ((size_t)c) << 40; #endif wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_5; break; case LWS_RXPS_04_FRAME_HDR_LEN64_5: #if defined __LP64__ wsi->rx_packet_length |= ((size_t)c) << 32; #endif wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_4; break; case LWS_RXPS_04_FRAME_HDR_LEN64_4: wsi->rx_packet_length |= ((size_t)c) << 24; wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_3; break; case LWS_RXPS_04_FRAME_HDR_LEN64_3: wsi->rx_packet_length |= ((size_t)c) << 16; wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_2; break; case LWS_RXPS_04_FRAME_HDR_LEN64_2: wsi->rx_packet_length |= ((size_t)c) << 8; wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_1; break; case LWS_RXPS_04_FRAME_HDR_LEN64_1: wsi->rx_packet_length |= (size_t)c; if (wsi->this_frame_masked) wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_1; else { if (wsi->rx_packet_length) wsi->lws_rx_parse_state = LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED; else { wsi->lws_rx_parse_state = LWS_RXPS_NEW; goto spill; } } break; case LWS_RXPS_07_COLLECT_FRAME_KEY_1: wsi->frame_masking_nonce_04[0] = c; if (c) wsi->all_zero_nonce = 0; wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_2; break; case LWS_RXPS_07_COLLECT_FRAME_KEY_2: wsi->frame_masking_nonce_04[1] = c; if (c) wsi->all_zero_nonce = 0; wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_3; break; case LWS_RXPS_07_COLLECT_FRAME_KEY_3: wsi->frame_masking_nonce_04[2] = c; if (c) wsi->all_zero_nonce = 0; wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_4; break; case LWS_RXPS_07_COLLECT_FRAME_KEY_4: wsi->frame_masking_nonce_04[3] = c; if (c) wsi->all_zero_nonce = 0; if (wsi->rx_packet_length) wsi->lws_rx_parse_state = LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED; else { wsi->lws_rx_parse_state = LWS_RXPS_NEW; goto spill; } 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->protocol->owning_server, wsi, LWS_CALLBACK_CLIENT_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; lwsl_parser("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) { lwsl_warn("LWS_RXPS_SEEN_76_FF: ERROR writing to socket\n"); return -1; } lwsl_parser(" 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: if ((!wsi->this_frame_masked) || wsi->all_zero_nonce) wsi->rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING + (wsi->rx_user_buffer_head++)] = c; else wsi->rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING + (wsi->rx_user_buffer_head++)] = wsi->xor_mask(wsi, c); if (--wsi->rx_packet_length == 0) { wsi->lws_rx_parse_state = LWS_RXPS_NEW; goto spill; } if (wsi->rx_user_buffer_head != MAX_USER_RX_BUFFER) break; spill: handled = 0; /* * is this frame a control packet we should take care of at this * layer? If so service it and hide it from the user callback */ switch (wsi->opcode) { case LWS_WS_OPCODE_07__CLOSE: /* is this an acknowledgement of our close? */ if (wsi->state == WSI_STATE_AWAITING_CLOSE_ACK) { /* * fine he has told us he is closing too, let's * finish our close */ lwsl_parser("seen server's close ack\n"); return -1; } lwsl_parser("client sees server close packet len = %d\n", wsi->rx_user_buffer_head); /* parrot the close packet payload back */ n = libwebsocket_write(wsi, (unsigned char *) &wsi->rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING], wsi->rx_user_buffer_head, LWS_WRITE_CLOSE); lwsl_parser("client writing close ack returned %d\n", n); wsi->state = WSI_STATE_RETURNED_CLOSE_ALREADY; /* close the connection */ return -1; case LWS_WS_OPCODE_07__PING: lwsl_info("client received ping, doing pong\n"); /* parrot the ping packet payload back as a pong*/ n = libwebsocket_write(wsi, (unsigned char *) &wsi->rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING], wsi->rx_user_buffer_head, LWS_WRITE_PONG); handled = 1; break; case LWS_WS_OPCODE_07__PONG: lwsl_info("client receied pong\n"); lwsl_hexdump(&wsi->rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING], wsi->rx_user_buffer_head); /* keep the statistics... */ wsi->pings_vs_pongs--; /* issue it */ callback_action = LWS_CALLBACK_CLIENT_RECEIVE_PONG; break; case LWS_WS_OPCODE_07__CONTINUATION: case LWS_WS_OPCODE_07__TEXT_FRAME: case LWS_WS_OPCODE_07__BINARY_FRAME: break; default: lwsl_parser("Reserved opcode 0x%2X\n", wsi->opcode); /* * It's something special we can't understand here. * Pass the payload up to the extension's parsing * state machine. */ eff_buf.token = &wsi->rx_user_buffer[ LWS_SEND_BUFFER_PRE_PADDING]; eff_buf.token_len = wsi->rx_user_buffer_head; for (n = 0; n < wsi->count_active_extensions; n++) { m = wsi->active_extensions[n]->callback( wsi->protocol->owning_server, wsi->active_extensions[n], wsi, LWS_EXT_CALLBACK_EXTENDED_PAYLOAD_RX, wsi->active_extensions_user[n], &eff_buf, 0); if (m) handled = 1; } if (!handled) { lwsl_ext("Unhandled extended opcode " "0x%x - ignoring frame\n", wsi->opcode); wsi->rx_user_buffer_head = 0; return 0; } break; } /* * No it's real payload, pass it up to the user callback. * It's nicely buffered with the pre-padding taken care of * so it can be sent straight out again using libwebsocket_write */ if (handled) goto already_done; eff_buf.token = &wsi->rx_user_buffer[ LWS_SEND_BUFFER_PRE_PADDING]; eff_buf.token_len = wsi->rx_user_buffer_head; for (n = 0; n < wsi->count_active_extensions; n++) { m = wsi->active_extensions[n]->callback( wsi->protocol->owning_server, wsi->active_extensions[n], wsi, LWS_EXT_CALLBACK_PAYLOAD_RX, wsi->active_extensions_user[n], &eff_buf, 0); if (m < 0) { lwsl_ext( "Extension '%s' failed to handle payload!\n", wsi->active_extensions[n]->name); return -1; } } if (eff_buf.token_len > 0) { eff_buf.token[eff_buf.token_len] = '\0'; if (wsi->protocol->callback) { if (callback_action == LWS_CALLBACK_CLIENT_RECEIVE_PONG) lwsl_info("Client doing pong callback\n"); wsi->protocol->callback( wsi->protocol->owning_server, wsi, (enum libwebsocket_callback_reasons)callback_action, wsi->user_space, eff_buf.token, eff_buf.token_len); } } already_done: wsi->rx_user_buffer_head = 0; break; default: lwsl_err("client rx illegal state\n"); return 1; } return 0; illegal_ctl_length: lwsl_warn("Control frame asking for " "extended length is illegal\n"); /* kill the connection */ return -1; }