352 lines
11 KiB
JavaScript
352 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 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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/**
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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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*/
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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 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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decode: 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 = structs.servicesBitfield.decode(buf.slice(4, 12));
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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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software: decodedUa.software,
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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 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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encode: function(opts) {
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// Deal with default options.
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var services = opts.services || [structs.servicesBitfield.NODE_NETWORK];
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var time = opts.time || new Date();
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var nonce = opts.nonce || exports.version.NONCE;
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assert(nonce.length === 8, "Bad nonce");
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var software = opts.software || 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(require("./").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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structs.servicesBitfield.encode(services),
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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(software),
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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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*/
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exports.addr = {
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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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decode: 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 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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encode: 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 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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decode: 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 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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encode: 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 = inv;
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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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*/
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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 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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decode: 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 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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encode: 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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/**
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* `object` message. An `object` is a message which is shared throughout
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* a stream. It is the only message which propagates; all others are
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* only between two nodes.
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* NOTE: You shouldn't use `encode` and `decode` methods directly.
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* Instead, get type of the object and process it using appropriate
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* namespace from `objects` module.
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* @see {@link https://bitmessage.org/wiki/Protocol_specification#object}
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* @namespace
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*/
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exports.object = {
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// Known types.
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GETPUBKEY: 0,
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PUBKEY: 1,
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MSG: 2,
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BROADCAST: 3,
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/**
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* Returns type of the `object` message if we can parse it. Per spec
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* we should still relay unknown objects.
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* @param {Buffer} buf - Message payload
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* @return {?number} Object type.
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*/
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getType: function(buf) {
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assert(buf.length >= 22, "object message payload is too small");
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return buf.readUInt32BE(16, true);
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},
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/**
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* Decode `object` message payload.
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* NOTE: `nonce` and `payload` are copied.
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* @param {Buffer} buf - Message payload
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* @return {Object} Decoded `object` structure.
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*/
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// FIXME(Kagami): Check for POW.
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// TODO(Kagami): Option to not fail on bad POW (may be useful for
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// bitchan).
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// TODO(Kagami): Option to not fail on expired object (would be useful
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// for bitchan).
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decode: function(buf) {
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// 8 + 8 + 4 + (1+) + (1+)
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assert(buf.length >= 22, "object message payload is too small");
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var nonce = new Buffer(8);
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buf.copy(nonce, 0, 0, 8);
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var expiresTime = util.readTimestamp64BE(buf.slice(8, 16));
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var ttl = expiresTime - util.tnow();
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assert(ttl >= -3600, "Object expired more than a hour ago");
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assert(ttl <= 2430000, "expiresTime is too far in the future");
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var type = buf.readUInt32BE(16, true);
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var decodedVersion = structs.var_int.decode(buf.slice(20));
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var decodedStream = structs.var_int.decode(decodedVersion.rest);
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var payload = new Buffer(decodedStream.rest.length);
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decodedStream.rest.copy(payload);
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return {
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nonce: nonce,
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ttl: ttl,
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type: type,
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version: decodedVersion.value,
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stream: decodedStream.value,
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payload: payload,
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};
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},
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/**
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* Encode `object` message payload.
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* @param {Object} opts - Object options
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* @return {Buffer} Encoded payload.
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*/
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// TODO(Kagami): Do a POW if nonce is not provided.
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encode: function(opts) {
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assert(opts.nonce.length === 8, "Bad nonce");
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assert(opts.ttl > 0, "Bad TTL");
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assert(opts.ttl <= 2430000, "TTL may not be larger than 28 days + 3 hours");
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var expiresTime = util.tnow() + opts.ttl;
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var type = new Buffer(4);
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type.writeUInt32BE(opts.type, 0);
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var stream = opts.stream || 1;
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return Buffer.concat([
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opts.nonce,
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util.writeUInt64BE(null, expiresTime),
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type,
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structs.var_int.encode(opts.version),
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structs.var_int.encode(stream),
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opts.payload,
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]);
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},
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};
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