/* * 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" int libwebsocket_client_rx_sm(struct libwebsocket *wsi, unsigned char c) { int callback_action = LWS_CALLBACK_CLIENT_RECEIVE; int handled; struct lws_tokens eff_buf; #ifndef LWS_NO_EXTENSIONS int n; int m; #endif switch (wsi->lws_rx_parse_state) { case LWS_RXPS_NEW: switch (wsi->ietf_spec_revision) { case 13: wsi->u.ws.opcode = c & 0xf; wsi->u.ws.rsv = (c & 0x70); wsi->u.ws.final = !!((c >> 7) & 1); switch (wsi->u.ws.opcode) { case LWS_WS_OPCODE_07__TEXT_FRAME: case LWS_WS_OPCODE_07__BINARY_FRAME: wsi->u.ws.frame_is_binary = wsi->u.ws.opcode == LWS_WS_OPCODE_07__BINARY_FRAME; break; } wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN; break; default: lwsl_err("unknown spec version %02d\n", wsi->ietf_spec_revision); break; } break; case LWS_RXPS_04_FRAME_HDR_LEN: wsi->u.ws.this_frame_masked = !!(c & 0x80); switch (c & 0x7f) { case 126: /* control frames are not allowed to have big lengths */ if (wsi->u.ws.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->u.ws.opcode & 8) goto illegal_ctl_length; wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_8; break; default: wsi->u.ws.rx_packet_length = c; if (wsi->u.ws.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->u.ws.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->u.ws.rx_packet_length |= c; if (wsi->u.ws.this_frame_masked) wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_1; else { if (wsi->u.ws.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->u.ws.rx_packet_length = ((size_t)c) << 56; #else wsi->u.ws.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->u.ws.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->u.ws.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->u.ws.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->u.ws.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->u.ws.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->u.ws.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->u.ws.rx_packet_length |= (size_t)c; if (wsi->u.ws.this_frame_masked) wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_1; else { if (wsi->u.ws.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->u.ws.frame_masking_nonce_04[0] = c; if (c) wsi->u.ws.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->u.ws.frame_masking_nonce_04[1] = c; if (c) wsi->u.ws.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->u.ws.frame_masking_nonce_04[2] = c; if (c) wsi->u.ws.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->u.ws.frame_masking_nonce_04[3] = c; if (c) wsi->u.ws.all_zero_nonce = 0; if (wsi->u.ws.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_PAYLOAD_UNTIL_LENGTH_EXHAUSTED: if (!wsi->u.ws.rx_user_buffer) lwsl_err("NULL client rx_user_buffer\n"); if ((!wsi->u.ws.this_frame_masked) || wsi->u.ws.all_zero_nonce) wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING + (wsi->u.ws.rx_user_buffer_head++)] = c; else wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING + (wsi->u.ws.rx_user_buffer_head++)] = c ^ wsi->u.ws.frame_masking_nonce_04[ (wsi->u.ws.frame_mask_index++) & 3]; if (--wsi->u.ws.rx_packet_length == 0) { /* spill because we have the whole frame */ wsi->lws_rx_parse_state = LWS_RXPS_NEW; goto spill; } /* * if there's no protocol max frame size given, we are * supposed to default to LWS_MAX_SOCKET_IO_BUF */ if (!wsi->protocol->rx_buffer_size && wsi->u.ws.rx_user_buffer_head != LWS_MAX_SOCKET_IO_BUF) break; else if (wsi->protocol->rx_buffer_size && wsi->u.ws.rx_user_buffer_head != wsi->protocol->rx_buffer_size) break; /* spill because we filled our rx buffer */ 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->u.ws.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 len = %d\n", wsi->u.ws.rx_user_buffer_head); /* * parrot the close packet payload back * we do not care about how it went, we are closing * immediately afterwards */ libwebsocket_write(wsi, (unsigned char *) &wsi->u.ws.rx_user_buffer[ LWS_SEND_BUFFER_PRE_PADDING], wsi->u.ws.rx_user_buffer_head, LWS_WRITE_CLOSE); 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 * !!! this may block or have partial write or fail * !!! very unlikely if the ping size is small */ libwebsocket_write(wsi, (unsigned char *) &wsi->u.ws.rx_user_buffer[ LWS_SEND_BUFFER_PRE_PADDING], wsi->u.ws.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->u.ws.rx_user_buffer[ LWS_SEND_BUFFER_PRE_PADDING], wsi->u.ws.rx_user_buffer_head); /* 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 opc 0x%2X\n", wsi->u.ws.opcode); #ifndef LWS_NO_EXTENSIONS /* * It's something special we can't understand here. * Pass the payload up to the extension's parsing * state machine. */ eff_buf.token = &wsi->u.ws.rx_user_buffer[ LWS_SEND_BUFFER_PRE_PADDING]; eff_buf.token_len = wsi->u.ws.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) { #else { #endif lwsl_ext("Unhandled ext opc 0x%x\n", wsi->u.ws.opcode); wsi->u.ws.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->u.ws.rx_user_buffer[ LWS_SEND_BUFFER_PRE_PADDING]; eff_buf.token_len = wsi->u.ws.rx_user_buffer_head; #ifndef LWS_NO_EXTENSIONS 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( "Ext '%s' failed to handle payload!\n", wsi->active_extensions[n]->name); return -1; } } #endif if (eff_buf.token_len <= 0) goto already_done; eff_buf.token[eff_buf.token_len] = '\0'; if (!wsi->protocol->callback) goto already_done; 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->u.ws.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; }