281 lines
8.9 KiB
JavaScript
281 lines
8.9 KiB
JavaScript
/************************************************************************
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* Copyright 2010-2015 Brian McKelvey.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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***********************************************************************/
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var bufferUtil = require('./BufferUtil').BufferUtil;
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var bufferAllocUnsafe = require('./utils').bufferAllocUnsafe;
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const DECODE_HEADER = 1;
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const WAITING_FOR_16_BIT_LENGTH = 2;
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const WAITING_FOR_64_BIT_LENGTH = 3;
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const WAITING_FOR_MASK_KEY = 4;
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const WAITING_FOR_PAYLOAD = 5;
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const COMPLETE = 6;
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// WebSocketConnection will pass shared buffer objects for maskBytes and
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// frameHeader into the constructor to avoid tons of small memory allocations
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// for each frame we have to parse. This is only used for parsing frames
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// we receive off the wire.
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function WebSocketFrame(maskBytes, frameHeader, config) {
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this.maskBytes = maskBytes;
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this.frameHeader = frameHeader;
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this.config = config;
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this.maxReceivedFrameSize = config.maxReceivedFrameSize;
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this.protocolError = false;
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this.frameTooLarge = false;
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this.invalidCloseFrameLength = false;
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this.parseState = DECODE_HEADER;
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this.closeStatus = -1;
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}
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WebSocketFrame.prototype.addData = function(bufferList) {
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if (this.parseState === DECODE_HEADER) {
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if (bufferList.length >= 2) {
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bufferList.joinInto(this.frameHeader, 0, 0, 2);
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bufferList.advance(2);
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var firstByte = this.frameHeader[0];
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var secondByte = this.frameHeader[1];
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this.fin = Boolean(firstByte & 0x80);
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this.rsv1 = Boolean(firstByte & 0x40);
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this.rsv2 = Boolean(firstByte & 0x20);
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this.rsv3 = Boolean(firstByte & 0x10);
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this.mask = Boolean(secondByte & 0x80);
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this.opcode = firstByte & 0x0F;
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this.length = secondByte & 0x7F;
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// Control frame sanity check
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if (this.opcode >= 0x08) {
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if (this.length > 125) {
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this.protocolError = true;
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this.dropReason = 'Illegal control frame longer than 125 bytes.';
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return true;
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}
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if (!this.fin) {
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this.protocolError = true;
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this.dropReason = 'Control frames must not be fragmented.';
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return true;
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}
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}
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if (this.length === 126) {
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this.parseState = WAITING_FOR_16_BIT_LENGTH;
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}
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else if (this.length === 127) {
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this.parseState = WAITING_FOR_64_BIT_LENGTH;
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}
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else {
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this.parseState = WAITING_FOR_MASK_KEY;
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}
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}
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}
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if (this.parseState === WAITING_FOR_16_BIT_LENGTH) {
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if (bufferList.length >= 2) {
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bufferList.joinInto(this.frameHeader, 2, 0, 2);
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bufferList.advance(2);
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this.length = this.frameHeader.readUInt16BE(2);
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this.parseState = WAITING_FOR_MASK_KEY;
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}
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}
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else if (this.parseState === WAITING_FOR_64_BIT_LENGTH) {
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if (bufferList.length >= 8) {
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bufferList.joinInto(this.frameHeader, 2, 0, 8);
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bufferList.advance(8);
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var lengthPair = [
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this.frameHeader.readUInt32BE(2),
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this.frameHeader.readUInt32BE(2+4)
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];
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if (lengthPair[0] !== 0) {
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this.protocolError = true;
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this.dropReason = 'Unsupported 64-bit length frame received';
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return true;
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}
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this.length = lengthPair[1];
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this.parseState = WAITING_FOR_MASK_KEY;
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}
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}
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if (this.parseState === WAITING_FOR_MASK_KEY) {
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if (this.mask) {
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if (bufferList.length >= 4) {
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bufferList.joinInto(this.maskBytes, 0, 0, 4);
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bufferList.advance(4);
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this.parseState = WAITING_FOR_PAYLOAD;
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}
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}
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else {
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this.parseState = WAITING_FOR_PAYLOAD;
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}
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}
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if (this.parseState === WAITING_FOR_PAYLOAD) {
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if (this.length > this.maxReceivedFrameSize) {
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this.frameTooLarge = true;
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this.dropReason = 'Frame size of ' + this.length.toString(10) +
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' bytes exceeds maximum accepted frame size';
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return true;
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}
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if (this.length === 0) {
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this.binaryPayload = bufferAllocUnsafe(0);
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this.parseState = COMPLETE;
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return true;
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}
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if (bufferList.length >= this.length) {
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this.binaryPayload = bufferList.take(this.length);
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bufferList.advance(this.length);
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if (this.mask) {
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bufferUtil.unmask(this.binaryPayload, this.maskBytes);
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// xor(this.binaryPayload, this.maskBytes, 0);
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}
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if (this.opcode === 0x08) { // WebSocketOpcode.CONNECTION_CLOSE
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if (this.length === 1) {
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// Invalid length for a close frame. Must be zero or at least two.
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this.binaryPayload = bufferAllocUnsafe(0);
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this.invalidCloseFrameLength = true;
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}
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if (this.length >= 2) {
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this.closeStatus = this.binaryPayload.readUInt16BE(0);
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this.binaryPayload = this.binaryPayload.slice(2);
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}
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}
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this.parseState = COMPLETE;
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return true;
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}
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}
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return false;
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};
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WebSocketFrame.prototype.throwAwayPayload = function(bufferList) {
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if (bufferList.length >= this.length) {
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bufferList.advance(this.length);
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this.parseState = COMPLETE;
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return true;
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}
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return false;
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};
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WebSocketFrame.prototype.toBuffer = function(nullMask) {
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var maskKey;
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var headerLength = 2;
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var data;
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var outputPos;
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var firstByte = 0x00;
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var secondByte = 0x00;
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if (this.fin) {
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firstByte |= 0x80;
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}
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if (this.rsv1) {
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firstByte |= 0x40;
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}
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if (this.rsv2) {
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firstByte |= 0x20;
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}
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if (this.rsv3) {
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firstByte |= 0x10;
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}
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if (this.mask) {
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secondByte |= 0x80;
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}
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firstByte |= (this.opcode & 0x0F);
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// the close frame is a special case because the close reason is
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// prepended to the payload data.
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if (this.opcode === 0x08) {
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this.length = 2;
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if (this.binaryPayload) {
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this.length += this.binaryPayload.length;
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}
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data = bufferAllocUnsafe(this.length);
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data.writeUInt16BE(this.closeStatus, 0);
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if (this.length > 2) {
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this.binaryPayload.copy(data, 2);
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}
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}
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else if (this.binaryPayload) {
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data = this.binaryPayload;
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this.length = data.length;
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}
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else {
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this.length = 0;
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}
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if (this.length <= 125) {
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// encode the length directly into the two-byte frame header
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secondByte |= (this.length & 0x7F);
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}
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else if (this.length > 125 && this.length <= 0xFFFF) {
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// Use 16-bit length
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secondByte |= 126;
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headerLength += 2;
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}
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else if (this.length > 0xFFFF) {
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// Use 64-bit length
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secondByte |= 127;
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headerLength += 8;
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}
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var output = bufferAllocUnsafe(this.length + headerLength + (this.mask ? 4 : 0));
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// write the frame header
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output[0] = firstByte;
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output[1] = secondByte;
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outputPos = 2;
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if (this.length > 125 && this.length <= 0xFFFF) {
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// write 16-bit length
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output.writeUInt16BE(this.length, outputPos);
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outputPos += 2;
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}
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else if (this.length > 0xFFFF) {
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// write 64-bit length
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output.writeUInt32BE(0x00000000, outputPos);
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output.writeUInt32BE(this.length, outputPos + 4);
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outputPos += 8;
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}
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if (this.mask) {
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maskKey = nullMask ? 0 : ((Math.random() * 0xFFFFFFFF) >>> 0);
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this.maskBytes.writeUInt32BE(maskKey, 0);
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// write the mask key
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this.maskBytes.copy(output, outputPos);
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outputPos += 4;
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if (data) {
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bufferUtil.mask(data, this.maskBytes, output, outputPos, this.length);
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}
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}
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else if (data) {
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data.copy(output, outputPos);
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}
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return output;
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};
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WebSocketFrame.prototype.toString = function() {
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return 'Opcode: ' + this.opcode + ', fin: ' + this.fin + ', length: ' + this.length + ', hasPayload: ' + Boolean(this.binaryPayload) + ', masked: ' + this.mask;
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};
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module.exports = WebSocketFrame;
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