391 lines
11 KiB
JavaScript
391 lines
11 KiB
JavaScript
/**
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* Working with messages.
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* @see {@link https://bitmessage.org/wiki/Protocol_specification#Message_types}
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* @see {@link https://bitmessage.org/wiki/Protocol_specification_v3#Message_types}
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* @see {@link https://bitmessage.org/Bitmessage%20Technical%20Paper.pdf}
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* @module bitmessage/messages
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*/
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// TODO(Kagami): Document object-like params.
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"use strict";
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var objectAssign = Object.assign || require("object-assign");
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var assert = require("./_util").assert;
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var structs = require("./structs");
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var UserAgent = require("./user-agent");
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var util = require("./_util");
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var message = structs.message;
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var ServicesBitfield = structs.ServicesBitfield;
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/**
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* Try to get command of the given encoded message.
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* Note that this function doesn't do any validation because it is
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* already provided by `message.decode` routine. Normally you call this
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* for each incoming message and then call decode function of the
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* appropriate message handler.
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* @param {Buffer} buf - Buffer that starts with encoded message
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* @return {?string} Message's command if any
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*/
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exports.getCommand = function(buf) {
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if (buf.length < 16) {
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return;
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}
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var command = buf.slice(4, 16);
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var firstNonNull = 0;
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for (var i = 11; i >=0; i--) {
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if (command[i] !== 0) {
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firstNonNull = i + 1;
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break;
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}
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}
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return command.slice(0, firstNonNull).toString("ascii");
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};
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/**
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* `version` message.
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* @see {@link https://bitmessage.org/wiki/Protocol_specification#version}
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* @namespace
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* @static
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*/
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var version = exports.version = {
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/** Random nonce used to detect connections to self. */
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NONCE: new Buffer("20bde0a3355dad78", "hex"),
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/**
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* Decode `version` message.
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* NOTE: `nonce` is copied.
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* @param {Buffer} buf - Message
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* @return {Object} Decoded `version` structure.
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*/
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decode: function(buf) {
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var decoded = message.decode(buf);
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assert(decoded.command === "version", "Bad command");
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return version.decodePayload(decoded.payload);
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},
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/**
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* Decode `version` message payload.
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* NOTE: `nonce` is copied.
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* @param {Buffer} buf - Message payload
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* @return {Object} Decoded `version` structure.
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*/
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decodePayload: function(buf) {
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// 4 + 8 + 8 + 26 + 26 + 8 + (1+) + (1+)
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assert(buf.length >= 82, "Buffer is too small");
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var protoVersion = buf.readUInt32BE(0, true);
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var services = ServicesBitfield(buf.slice(4, 12), {copy: true});
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var time = util.readTime64BE(buf, 12);
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var short = {short: true};
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var addrRecv = structs.net_addr.decode(buf.slice(20, 46), short);
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var addrFrom = structs.net_addr.decode(buf.slice(46, 72), short);
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var nonce = new Buffer(8);
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buf.copy(nonce, 0, 72, 80);
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var decodedUa = UserAgent.decode(buf.slice(80));
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var decodedStreamNumbers = structs.var_int_list.decode(decodedUa.rest);
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return {
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version: protoVersion,
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services: services,
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time: time,
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remoteHost: addrRecv.host,
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remotePort: addrRecv.port,
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port: addrFrom.port,
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nonce: nonce,
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userAgent: decodedUa.str,
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streamNumbers: decodedStreamNumbers.list,
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// NOTE(Kagami): Real data length. It may be some gap between end
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// of stream numbers list and end of payload:
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// [payload..............[stream numbers]xxxx]
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// We are currently ignoring that.
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length: 80 + decodedUa.length + decodedStreamNumbers.length,
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};
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},
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/**
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* Encode `version` message.
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* @param {Object} opts - Version options
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* @return {Buffer} Encoded message.
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*/
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encode: function(opts) {
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var payload = version.encodePayload(opts);
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return message.encode("version", payload);
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},
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/**
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* Encode `version` message payload.
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* @param {Object} opts - Version options
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* @return {Buffer} Encoded payload.
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*/
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encodePayload: function(opts) {
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// Deal with default options.
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var services = opts.services ||
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ServicesBitfield().set(ServicesBitfield.NODE_NETWORK);
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var time = opts.time || new Date();
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var nonce = opts.nonce || version.NONCE;
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assert(nonce.length === 8, "Bad nonce");
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var userAgent = opts.userAgent || UserAgent.SELF;
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var streamNumbers = opts.streamNumbers || [1];
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// Start encoding.
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var protoVersion = new Buffer(4);
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protoVersion.writeUInt32BE(util.PROTOCOL_VERSION, 0);
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var addrRecv = structs.net_addr.encode({
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services: services,
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host: opts.remoteHost,
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port: opts.remotePort,
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short: true,
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});
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var addrFrom = structs.net_addr.encode({
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services: services,
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host: "127.0.0.1",
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port: opts.port,
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short: true,
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});
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return Buffer.concat([
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protoVersion,
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services.buffer,
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util.writeTime64BE(null, time),
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addrRecv,
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addrFrom,
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nonce,
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UserAgent.encode(userAgent),
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structs.var_int_list.encode(streamNumbers),
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]);
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},
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};
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/**
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* `addr` message. Provide information on known nodes of the network.
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* @see {@link https://bitmessage.org/wiki/Protocol_specification#addr}
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* @namespace
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* @static
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*/
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var addr = exports.addr = {
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/**
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* Decode `addr` message.
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* @param {Buffer} buf - Message
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* @return {Object} Decoded `addr` structure.
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*/
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decode: function(buf) {
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var decoded = message.decode(buf);
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assert(decoded.command === "addr", "Bad command");
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return addr.decodePayload(decoded.payload);
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},
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/**
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* Decode `addr` message payload.
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* @param {Buffer} buf - Message payload
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* @return {Object} Decoded `addr` structure.
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*/
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decodePayload: function(buf) {
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var decoded = structs.var_int.decode(buf);
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var listLength = decoded.value;
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assert(listLength <= 1000, "Too many address entires");
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var length = decoded.length + listLength * 38;
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assert(buf.length >= length, "Buffer is too small");
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var rest = decoded.rest;
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var addrs = new Array(listLength);
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for (var i = 0; i < listLength; i++) {
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addrs[i] = structs.net_addr.decode(rest.slice(i*38, (i+1)*38));
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}
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return {
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addrs: addrs,
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// Real data length.
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length: length,
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};
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},
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/**
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* Encode `addr` message.
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* @param {Object[]} addrs - Network addresses
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* @return {Buffer} Encoded message.
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*/
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encode: function(addrs) {
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var payload = addr.encodePayload(addrs);
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return message.encode("addr", payload);
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},
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/**
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* Encode `addr` message payload.
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* @param {Object[]} addrs - Network addresses
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* @return {Buffer} Encoded payload.
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*/
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encodePayload: function(addrs) {
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assert(addrs.length <= 1000, "Too many address entires");
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var addrsBuf = Buffer.concat(addrs.map(structs.net_addr.encode));
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return Buffer.concat([structs.var_int.encode(addrs.length), addrsBuf]);
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},
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};
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/**
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* `inv` message. Allows a node to advertise its knowledge of one or
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* more objects.
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* @see {@link https://bitmessage.org/wiki/Protocol_specification#inv}
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* @namespace
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* @static
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*/
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var inv = exports.inv = {
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/**
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* Decode `inv` message.
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* @param {Buffer} buf - Message
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* @return {Object} Decoded `inv` structure.
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*/
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decode: function(buf) {
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var decoded = message.decode(buf);
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assert(decoded.command === "inv", "Bad command");
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return inv.decodePayload(decoded.payload);
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},
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/**
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* Decode `inv` message payload.
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* @param {Buffer} buf - Message payload
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* @return {Object} Decoded `inv` structure.
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*/
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decodePayload: function(buf) {
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var decoded = structs.var_int.decode(buf);
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var listLength = decoded.value;
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assert(listLength <= 50000, "Too many inventory entires");
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var length = decoded.length + listLength * 32;
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assert(buf.length >= length, "Buffer is too small");
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var rest = decoded.rest;
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var inventory = new Array(listLength);
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for (var i = 0; i < listLength; i++) {
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inventory[i] = rest.slice(i*32, (i+1)*32);
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}
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return {
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inventory: inventory,
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// Real data length.
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length: length,
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};
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},
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/**
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* Encode `inv` message.
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* @param {Buffer[]} inventory - Inventory vector list (encoded)
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* @return {Buffer} Encoded message.
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*/
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encode: function(inventory) {
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var payload = inv.encodePayload(inventory);
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return message.encode("inv", payload);
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},
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/**
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* Encode `inv` message payload.
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* @param {Buffer[]} inventory - Inventory vector list (encoded)
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* @return {Buffer} Encoded payload.
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*/
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encodePayload: function(inventory) {
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assert(inventory.length <= 50000, "Too many inventory entires");
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var invBuf = Buffer.concat(inventory);
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return Buffer.concat([structs.var_int.encode(inventory.length), invBuf]);
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},
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};
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/**
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* `getdata` message. `getdata` is used in response to an `inv` message
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* to retrieve the content of a specific object after filtering known
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* elements.
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* @see {@link https://bitmessage.org/wiki/Protocol_specification#getdata}
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* @namespace
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*/
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exports.getdata = objectAssign({}, inv, {
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decode: function(buf) {
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var decoded = message.decode(buf);
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assert(decoded.command === "getdata", "Bad command");
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return inv.decodePayload(decoded.payload);
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},
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encode: function(inventory) {
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var payload = inv.encodePayload(inventory);
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return message.encode("getdata", payload);
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},
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});
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/**
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* `error` message.
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* @see {@link https://bitmessage.org/wiki/Protocol_specification_v3#error}
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* @namespace
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* @static
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*/
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var error = exports.error = {
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/**
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* Just a warning.
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*/
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WARNING: 0,
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/**
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* It's an error, something was going wrong (e.g. an object got lost).
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*/
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ERROR: 1,
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/**
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* It's a fatal error. The node will drop the line for that error and
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* maybe ban you for some time.
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*/
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FATAL: 2,
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/**
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* Decode `error` message.
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* @param {Buffer} buf - Message
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* @return {Object} Decoded `error` structure.
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*/
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decode: function(buf) {
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var decoded = message.decode(buf);
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assert(decoded.command === "error", "Bad command");
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return error.decodePayload(decoded.payload);
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},
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/**
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* Decode `error` message payload.
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* @param {Buffer} buf - Message payload
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* @return {Object} Decoded `error` structure.
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*/
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decodePayload: function(buf) {
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assert(buf.length >= 4, "Buffer is too small");
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var decodedFatal = structs.var_int.decode(buf);
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var decodedBanTime = structs.var_int.decode(decodedFatal.rest);
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var decodedVector = structs.var_str.decode(decodedBanTime.rest);
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var decodedErrorText = structs.var_str.decode(decodedVector.rest);
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var length = (
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decodedFatal.length +
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decodedBanTime.length +
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decodedVector.length +
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decodedErrorText.length
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);
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return {
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fatal: decodedFatal.value,
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banTime: decodedBanTime.value,
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vector: decodedVector.str,
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errorText: decodedErrorText.str,
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// Real data length.
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length: length,
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};
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},
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/**
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* Encode `error` message.
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* @param {Object} opts - Error options
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* @return {Buffer} Encoded message.
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*/
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encode: function(opts) {
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var payload = error.encodePayload(opts);
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return message.encode("error", payload);
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},
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/**
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* Encode `error` message payload.
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* @param {Object} opts - Error options
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* @return {Buffer} Encoded payload.
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*/
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encodePayload: function(opts) {
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var fatal = opts.fatal || error.WARNING;
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var banTime = opts.banTime || 0;
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var vector = opts.vector || "";
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var errorText = opts.errorText || "";
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return Buffer.concat([
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structs.var_int.encode(fatal),
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structs.var_int.encode(banTime),
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structs.var_str.encode(vector),
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structs.var_str.encode(errorText),
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]);
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},
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};
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