/**
* Working with messages.
* @see {@link https://bitmessage.org/wiki/Protocol_specification#Message_types}
* @see {@link https://bitmessage.org/wiki/Protocol_specification_v3#Message_types}
* @see {@link https://bitmessage.org/Bitmessage%20Technical%20Paper.pdf}
* @module bitmessage/messages
* @example
* var structs = require("bitmessage").structs;
* var messages = require("bitmessage").messages;
*
* // Simple encoding and decoding:
* var vermsg = messages.version.encode({
* remoteHost: "1.1.1.1",
* remotePort: 8444,
* });
* console.log(messages.version.decode(vermsg).remoteHost); // 1.1.1.1
*
* // Low-level encoding and decoding:
* var addrPayload = messages.addr.encodePayload([
* {host: "2.2.2.2", port: 28444},
* ]);
* var addrmsg = structs.message.encode("addr", addrPayload);
* var decoded = structs.message.decode(addrmsg);
* console.log(decoded.command); // addr
* var addr = messages.addr.decodePayload(decoded.payload);
* console.log(addr.addrs[0].host); // 2.2.2.2
*
* // Encode with empty payload:
* var verackmsg = structs.message.encode("verack");
* console.log(structs.message.decode(verackmsg).command); // verack
*/
"use strict";
var objectAssign = Object.assign || require("object-assign");
var bufferEqual = require("buffer-equal");
var assert = require("./_util").assert;
var structs = require("./structs");
var bmcrypto = require("./crypto");
var UserAgent = require("./user-agent");
var util = require("./_util");
var message = structs.message;
var ServicesBitfield = structs.ServicesBitfield;
var IPv4_MAPPING = util.IPv4_MAPPING;
var inet_pton = util.inet_pton;
/**
* Try to get command of the given encoded message.
* Note that this function doesn't do any validation because it is
* already provided by
* [message.decode]{@link module:bitmessage/structs.message.decode}
* routine.
* @param {Buffer} buf - Buffer that starts with encoded message
* @return {?string} Message's command if any.
*/
exports.getCommand = function(buf) {
if (buf.length < 16) {
return;
}
var command = buf.slice(4, 16);
var firstNonNull = 0;
for (var i = 11; i >=0; i--) {
if (command[i] !== 0) {
firstNonNull = i + 1;
break;
}
}
return command.slice(0, firstNonNull).toString("ascii");
};
/**
* `version` message.
* @see {@link https://bitmessage.org/wiki/Protocol_specification#version}
* @namespace
* @static
*/
var version = exports.version = {
/**
* @typedef {Object} DecodeResult
* @property {number} protoVersion - Identifies protocol version being
* used by the node. Should equal 3. Nodes should disconnect if the
* remote node's version is lower but continue with the connection if
* it is higher.
* @property {Object} services -
* [Service]{@link module:bitmessage/structs.ServicesBitfield}
* features to be enabled for this connection
* @property {Date} time - Node time
* @property {string} remoteHost - IPv4/IPv6 address of the node
* receiving this message
* @property {number} remotePort - Port of the node receiving this
* message
* @property {number} port - Incoming port of the node sending this
* message
* @property {Buffer} nonce - An 8-byte random nonce used to detect
* connection to self
* @property {string} userAgent - [User agent]{@link
* module:bitmessage/user-agent} of the node
* @property {number[]} streams - Streams accepted by the node
* @property {number} length - Real data length
* @memberof module:bitmessage/messages.version
*/
/**
* Random nonce used to detect connections to self.
* @constant {Buffer}
*/
randomNonce: bmcrypto.randomBytes(8),
/**
* Decode `version` message.
* NOTE: `nonce` is copied.
* @param {Buffer} buf - Message
* @return {DecodeResult}
* [Decoded `version` structure.]{@link module:bitmessage/messages.version.DecodeResult}
*/
decode: function(buf) {
var decoded = message.decode(buf);
assert(decoded.command === "version", "Bad command");
return version.decodePayload(decoded.payload);
},
/**
* Decode `version` message payload.
* The same as [decode]{@link module:bitmessage/messages.version.decode}.
*/
decodePayload: function(buf) {
// 4 + 8 + 8 + 26 + 26 + 8 + (1+) + (1+)
assert(buf.length >= 82, "Buffer is too small");
var protoVersion = buf.readUInt32BE(0, true);
var services = ServicesBitfield(buf.slice(4, 12), {copy: true});
var time = util.readTime64BE(buf, 12);
var short = {short: true};
var addrRecv = structs.net_addr.decode(buf.slice(20, 46), short);
var addrFrom = structs.net_addr.decode(buf.slice(46, 72), short);
var nonce = new Buffer(8);
buf.copy(nonce, 0, 72, 80);
var decodedUa = UserAgent.decode(buf.slice(80));
assert(decodedUa.length <= 5000, "User agent is too long");
var decodedStreams = structs.var_int_list.decode(decodedUa.rest);
assert(decodedStreams.list.length <= 160000, "Too many streams");
return {
protoVersion: protoVersion,
services: services,
time: time,
remoteHost: addrRecv.host,
remotePort: addrRecv.port,
port: addrFrom.port,
nonce: nonce,
userAgent: decodedUa.str,
streams: decodedStreams.list,
// NOTE(Kagami): Real data length. It may be some gap between end
// of stream numbers list and end of payload:
// [payload..............[stream numbers]xxxx]
// We are currently ignoring that.
length: 80 + decodedUa.length + decodedStreams.length,
};
},
/**
* Encode `version` message.
* @param {Object} opts - Version options
* @param {Object=} opts.services -
* [Service]{@link module:bitmessage/structs.ServicesBitfield}
* features to be enabled for this connection (`NODE_NETWORK` by
* default)
* @param {Date=} opts.time - Node time (current time by default)
* @param {string} opts.remoteHost - IPv4/IPv6 address of the node
* receiving this message
* @param {number} opts.remotePort - Port of the node receiving this
* message
* @param {number=} opts.port - Incoming port of the node (8444 by
* default)
* @param {Buffer=} opts.nonce - An 8-byte random nonce used to detect
* connection to self (unique per node.js process by default)
* @param {(Array|string|Buffer)=} opts.userAgent -
* [User agent]{@link module:bitmessage/user-agent} of the node
* (user agent of bitmessage library by default)
* @param {Array<number>=} opts.streams - Streams accepted by the node
* ([1] by default)
* @return {Buffer} Encoded message.
*/
encode: function(opts) {
var payload = version.encodePayload(opts);
return message.encode("version", payload);
},
/**
* Encode `version` message payload.
* The same as [encode]{@link module:bitmessage/messages.version.encode}.
*/
encodePayload: function(opts) {
// Deal with default options.
var services = opts.services ||
ServicesBitfield().set(ServicesBitfield.NODE_NETWORK);
var time = opts.time || new Date();
var nonce = opts.nonce || version.randomNonce;
assert(nonce.length === 8, "Bad nonce");
var port = opts.port || 8444;
var userAgent = UserAgent.encode(opts.userAgent || UserAgent.SELF);
assert(userAgent.length <= 5000, "User agent is too long");
var streams = opts.streams || [1];
assert(streams.length <= 160000, "Too many streams");
// Start encoding.
var protoVersion = new Buffer(4);
protoVersion.writeUInt32BE(util.PROTOCOL_VERSION, 0);
var addrRecv = structs.net_addr.encode({
services: services,
host: opts.remoteHost,
port: opts.remotePort,
short: true,
});
var addrFrom = structs.net_addr.encode({
services: services,
host: "127.0.0.1",
port: port,
short: true,
});
return Buffer.concat([
protoVersion,
services.buffer,
util.writeTime64BE(null, time),
addrRecv,
addrFrom,
nonce,
userAgent,
structs.var_int_list.encode(streams),
]);
},
};
var IPv6_LOOPBACK = new Buffer(
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]
);
// Check whether given encoded IPv6 or IPv4-mapped IPv6 is in private
// network range. See
// <https://en.wikipedia.org/wiki/Reserved_IP_addresses> for details.
// TODO(Kagami): Do we also need to filter multicasts and other reserved
// ranges?
function isPrivateIp(buf) {
// IPv4.
if (bufferEqual(buf.slice(0, 12), IPv4_MAPPING)) {
buf = buf.slice(12);
if (buf[0] === 127) {
return true;
} else if (buf[0] === 10) {
return true;
} else if (buf[0] === 192 && buf[1] === 168) {
return true;
// XXX(Kagami): ignore:start and ignore:end doesn't ignore this for
// some reason. Probably related:
// <https://github.com/jshint/jshint/issues/1465>.
} else if (buf[0] === 172 && (buf[1] & 0xf0) === 0x10) {//jshint ignore:line
return true;
} else if (buf[0] === 169 && buf[1] === 254) {
return true;
} else {
return false;
}
// IPv6.
} else {
if (bufferEqual(buf, IPv6_LOOPBACK)) {
return true;
} else if (buf[0] === 0xfe && (buf[1] & 0xc0) === 0x80) {//jshint ignore:line
return true;
} else if ((buf[0] & 0xfe) === 0xfc) { // jshint ignore:line
return true;
} else {
return false;
}
}
}
// Helper to make it easier to filter out private IPs.
function checkAddrOpts(opts) {
return !isPrivateIp(inet_pton(opts.host));
}
/**
* `addr` message. Provide information on known nodes of the network.
* @see {@link https://bitmessage.org/wiki/Protocol_specification#addr}
* @namespace
* @static
*/
var addr = exports.addr = {
/**
* @typedef {Object} DecodeResult
* @property {Object[]} addrs - List of
* [decoded `net_addr` structures]{@link module:bitmessage/structs.net_addr.DecodeResult}
* @property {number} length - Real data length
* @memberof module:bitmessage/messages.addr
*/
/**
* Decode `addr` message.
* @param {Buffer} buf - Message
* @return {DecodeResult}
* [Decoded `addr` structure.]{@link module:bitmessage/messages.addr.DecodeResult}
*/
decode: function(buf) {
var decoded = message.decode(buf);
assert(decoded.command === "addr", "Bad command");
return addr.decodePayload(decoded.payload);
},
/**
* Decode `addr` message payload.
* The same as [decode]{@link module:bitmessage/messages.addr.decode}.
*/
decodePayload: function(buf) {
var decoded = structs.var_int.decode(buf);
var listLength = decoded.value;
// NOTE(Kagami): Check length before filtering private IPs because
// we shouldn't even receive them.
assert(listLength <= 1000, "Too many address entires");
var length = decoded.length + listLength * 38;
assert(buf.length >= length, "Buffer is too small");
var rest = decoded.rest;
var addrs = [];
var addrBuf;
for (var i = 0; i < listLength; i++) {
addrBuf = rest.slice(i*38, (i+1)*38);
if (!isPrivateIp(addrBuf.slice(20, 36))) {
addrs.push(structs.net_addr.decode(addrBuf));
}
}
return {
addrs: addrs,
// Real data length.
length: length,
};
},
/**
* Encode `addr` message.
* @param {Object[]} addrs - List of
* [net_addr encode options]{@link module:bitmessage/structs.net_addr.encode}
* @return {Buffer} Encoded message.
*/
encode: function(addrs) {
var payload = addr.encodePayload(addrs);
return message.encode("addr", payload);
},
/**
* Encode `addr` message payload.
* The same as [encode]{@link module:bitmessage/messages.addr.encode}.
*/
encodePayload: function(addrs) {
addrs = addrs.filter(checkAddrOpts);
assert(addrs.length <= 1000, "Too many address entires");
var addrBufs = addrs.map(structs.net_addr.encode);
var bufs = [structs.var_int.encode(addrs.length)].concat(addrBufs);
return Buffer.concat(bufs);
},
};
/**
* `inv` message. Allows a node to advertise its knowledge of one or
* more objects.
* @see {@link https://bitmessage.org/wiki/Protocol_specification#inv}
* @namespace
* @static
*/
var inv = exports.inv = {
/**
* @typedef {Object} DecodeResult
* @property {Buffer[]} inventory - List of
* [inventory vectors]{@link module:bitmessage/structs.inv_vect}
* @property {number} length - Real data length
* @memberof module:bitmessage/messages.inv
*/
/**
* Decode `inv` message.
* @param {Buffer} buf - Message
* @return {DecodeResult}
* [Decoded `inv` structure.]{@link module:bitmessage/messages.inv.DecodeResult}
*/
decode: function(buf) {
var decoded = message.decode(buf);
assert(decoded.command === "inv", "Bad command");
return inv.decodePayload(decoded.payload);
},
/**
* Decode `inv` message payload.
* The same as [decode]{@link module:bitmessage/messages.inv.decode}.
*/
decodePayload: function(buf) {
var decoded = structs.var_int.decode(buf);
var listLength = decoded.value;
assert(listLength <= 50000, "Too many inventory entires");
var length = decoded.length + listLength * 32;
assert(buf.length >= length, "Buffer is too small");
var rest = decoded.rest;
var inventory = new Array(listLength);
for (var i = 0; i < listLength; i++) {
inventory[i] = rest.slice(i*32, (i+1)*32);
}
return {
inventory: inventory,
// Real data length.
length: length,
};
},
/**
* Encode `inv` message.
* @param {Buffer[]} inventory -
* [Inventory vector]{@link module:bitmessage/structs.inv_vect} list
* @return {Buffer} Encoded message.
*/
encode: function(inventory) {
var payload = inv.encodePayload(inventory);
return message.encode("inv", payload);
},
/**
* Encode `inv` message payload.
* The same as [encode]{@link module:bitmessage/messages.inv.encode}.
*/
encodePayload: function(inventory) {
assert(inventory.length <= 50000, "Too many inventory entires");
// TODO(Kagami): Validate vectors length.
var bufs = [structs.var_int.encode(inventory.length)].concat(inventory);
return Buffer.concat(bufs);
},
};
/**
* `getdata` message. `getdata` is used in response to an
* [inv]{@link module:bitmessage/messages.inv} message to retrieve the
* content of a specific object after filtering known elements.
* @see {@link https://bitmessage.org/wiki/Protocol_specification#getdata}
* @namespace
*/
exports.getdata = objectAssign({}, inv, {
/**
* @typedef {Object} DecodeResult
* @property {Buffer[]} inventory - List of
* [inventory vectors]{@link module:bitmessage/structs.inv_vect}
* @property {number} length - Real data length
* @memberof module:bitmessage/messages.getdata
*/
/**
* Decode `getdata` message.
* @param {Buffer} buf - Message
* @return {DecodeResult}
* [Decoded `getdata` structure.]{@link module:bitmessage/messages.getdata.DecodeResult}
* @memberof module:bitmessage/messages.getdata
*/
decode: function(buf) {
var decoded = message.decode(buf);
assert(decoded.command === "getdata", "Bad command");
return inv.decodePayload(decoded.payload);
},
/**
* Decode `getdata` message payload.
* The same as [decode]{@link module:bitmessage/messages.getdata.decode}.
* @function decodePayload
* @memberof module:bitmessage/messages.getdata
*/
/**
* Encode `getdata` message.
* @param {Buffer[]} inventory -
* [Inventory vector]{@link module:bitmessage/structs.inv_vect} list
* @return {Buffer} Encoded message.
* @memberof module:bitmessage/messages.getdata
*/
encode: function(inventory) {
var payload = inv.encodePayload(inventory);
return message.encode("getdata", payload);
},
/**
* Encode `getdata` message payload.
* The same as [encode]{@link module:bitmessage/messages.getdata.encode}.
* @function encodePayload
* @memberof module:bitmessage/messages.getdata
*/
});
/**
* `error` message.
* @see {@link https://bitmessage.org/wiki/Protocol_specification_v3#error}
* @namespace
* @static
*/
var error = exports.error = {
/**
* Just a warning.
* @constant {number}
*/
WARNING: 0,
/**
* It's an error, something was going wrong (e.g. an object got lost).
* @constant {number}
*/
ERROR: 1,
/**
* It's a fatal error. The node will drop the line for that error and
* maybe ban you for some time.
* @constant {number}
*/
FATAL: 2,
/**
* Convert error type to a human-readable string.
* @param {number} type - Type of the error
* @return {string}
*/
type2str: function(type) {
switch (type) {
case error.WARNING: return "warning";
case error.ERROR: return "error";
case error.FATAL: return "fatal";
default: return "unknown";
}
},
/**
* @typedef {Object} DecodeResult
* @property {number} type - Type of the error
* @property {number} banTime - The other node informs that it will
* not accept further connections for this number of seconds
* @property {?Buffer} vector -
* [Inventory vector]{@link module:bitmessage/structs.inv_vect}
* related to the error
* @property {string} errorText - A human-readable error description
* @property {number} length - Real data length
* @memberof module:bitmessage/messages.error
*/
/**
* Decode `error` message.
* @param {Buffer} buf - Message
* @return {DecodeResult}
* [Decoded `error` structure.]{@link module:bitmessage/messages.error.DecodeResult}
*/
decode: function(buf) {
var decoded = message.decode(buf);
assert(decoded.command === "error", "Bad command");
return error.decodePayload(decoded.payload);
},
/**
* Decode `error` message payload.
* The same as [decode]{@link module:bitmessage/messages.error.decode}.
*/
decodePayload: function(buf) {
assert(buf.length >= 4, "Buffer is too small");
var decodedType = structs.var_int.decode(buf);
var decodedBanTime = structs.var_int.decode(decodedType.rest);
var decodedVectorLength = structs.var_int.decode(decodedBanTime.rest);
// NOTE(Kagami): Inventory vector should be only 32-byte in size but
// currently we don't ensure it.
var vectorLength = decodedVectorLength.value;
var rest = decodedVectorLength.rest;
assert(rest.length >= vectorLength, "Buffer is too small");
var vector = null;
if (vectorLength) {
vector = new Buffer(vectorLength);
rest.copy(vector);
rest = rest.slice(vectorLength);
}
var decodedErrorText = structs.var_str.decode(rest);
var length = (
decodedType.length +
decodedBanTime.length +
decodedVectorLength.length + vectorLength +
decodedErrorText.length
);
return {
type: decodedType.value,
banTime: decodedBanTime.value,
vector: vector,
errorText: decodedErrorText.str,
// Real data length.
length: length,
};
},
/**
* Encode `error` message.
* @param {Object} opts - Error options
* @param {number=} opts.type - Type of the error
* ([warning]{@link module:bitmessage/messages.error.WARNING} by
* default)
* @param {number=} opts.banTime - Inform the other node, that you
* will not accept further connections for this number of seconds (0
* by default)
* @param {Buffer=} opts.vector - A 32-byte
* [inventory vector]{@link module:bitmessage/structs.inv_vect}
* related to the error (empty by default)
* @param {string} opts.errorText - A human-readable error description
* @return {Buffer} Encoded message.
*/
encode: function(opts) {
var payload = error.encodePayload(opts);
return message.encode("error", payload);
},
/**
* Encode `error` message payload.
* The same as [encode]{@link module:bitmessage/messages.error.encode}.
*/
encodePayload: function(opts) {
var type = opts.type || error.WARNING;
var banTime = opts.banTime || 0;
// TODO(Kagami): Validate vector length.
var vector = opts.vector || new Buffer(0);
return Buffer.concat([
structs.var_int.encode(type),
structs.var_int.encode(banTime),
structs.var_int.encode(vector.length),
vector,
structs.var_str.encode(opts.errorText),
]);
},
};