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var arrayRemove = require('unordered-array-remove')
var debug = require('debug')('webtorrent:peer')
var Wire = require('bittorrent-protocol')
var WebConn = require('./webconn')
var CONNECT_TIMEOUT_TCP = 5000
var CONNECT_TIMEOUT_WEBRTC = 25000
var HANDSHAKE_TIMEOUT = 25000
/**
* WebRTC peer connections start out connected, because WebRTC peers require an
* "introduction" (i.e. WebRTC signaling), and there's no equivalent to an IP address
* that lets you refer to a WebRTC endpoint.
*/
exports.createWebRTCPeer = function (conn, swarm) {
var peer = new Peer(conn.id, 'webrtc')
peer.conn = conn
peer.swarm = swarm
if (peer.conn.connected) {
peer.onConnect()
} else {
peer.conn.once('connect', function () { peer.onConnect() })
peer.conn.once('error', function (err) { peer.destroy(err) })
peer.startConnectTimeout()
}
return peer
}
/**
* Incoming TCP peers start out connected, because the remote peer connected to the
* listening port of the TCP server. Until the remote peer sends a handshake, we don't
* know what swarm the connection is intended for.
*/
exports.createTCPIncomingPeer = function (conn) {
var addr = conn.remoteAddress + ':' + conn.remotePort
var peer = new Peer(addr, 'tcpIncoming')
peer.conn = conn
peer.addr = addr
peer.onConnect()
return peer
}
/**
* Outgoing TCP peers start out with just an IP address. At some point (when there is an
* available connection), the client can attempt to connect to the address.
*/
exports.createTCPOutgoingPeer = function (addr, swarm) {
var peer = new Peer(addr, 'tcpOutgoing')
peer.addr = addr
peer.swarm = swarm
return peer
}
/**
* Peer that represents a Web Seed (BEP17 / BEP19).
*/
exports.createWebSeedPeer = function (url, swarm) {
var peer = new Peer(url, 'webSeed')
peer.swarm = swarm
peer.conn = new WebConn(url, swarm)
peer.onConnect()
return peer
}
/**
* Peer. Represents a peer in the torrent swarm.
*
* @param {string} id "ip:port" string, peer id (for WebRTC peers), or url (for Web Seeds)
* @param {string} type the type of the peer
*/
function Peer (id, type) {
var self = this
self.id = id
self.type = type
debug('new %s Peer %s', type, id)
self.addr = null
self.conn = null
self.swarm = null
self.wire = null
self.connected = false
self.destroyed = false
self.timeout = null // handshake timeout
self.retries = 0 // outgoing TCP connection retry count
self.sentHandshake = false
}
/**
* Called once the peer is connected (i.e. fired 'connect' event)
* @param {Socket} conn
*/
Peer.prototype.onConnect = function () {
var self = this
if (self.destroyed) return
self.connected = true
debug('Peer %s connected', self.id)
clearTimeout(self.connectTimeout)
var conn = self.conn
conn.once('end', function () {
self.destroy()
})
conn.once('close', function () {
self.destroy()
})
conn.once('finish', function () {
self.destroy()
})
conn.once('error', function (err) {
self.destroy(err)
})
var wire = self.wire = new Wire()
wire.type = self.type
wire.once('end', function () {
self.destroy()
})
wire.once('close', function () {
self.destroy()
})
wire.once('finish', function () {
self.destroy()
})
wire.once('error', function (err) {
self.destroy(err)
})
wire.once('handshake', function (infoHash, peerId) {
self.onHandshake(infoHash, peerId)
})
self.startHandshakeTimeout()
conn.pipe(wire).pipe(conn)
if (self.swarm && !self.sentHandshake) self.handshake()
}
/**
* Called when handshake is received from remote peer.
* @param {string} infoHash
* @param {string} peerId
*/
Peer.prototype.onHandshake = function (infoHash, peerId) {
var self = this
if (!self.swarm) return // `self.swarm` not set yet, so do nothing
if (self.destroyed) return
if (self.swarm.destroyed) {
return self.destroy(new Error('swarm already destroyed'))
}
if (infoHash !== self.swarm.infoHash) {
return self.destroy(new Error('unexpected handshake info hash for this swarm'))
}
if (peerId === self.swarm.peerId) {
return self.destroy(new Error('refusing to connect to ourselves'))
}
debug('Peer %s got handshake %s', self.id, infoHash)
clearTimeout(self.handshakeTimeout)
self.retries = 0
var addr = self.addr
if (!addr && self.conn.remoteAddress && self.conn.remotePort) {
addr = self.conn.remoteAddress + ':' + self.conn.remotePort
}
self.swarm._onWire(self.wire, addr)
// swarm could be destroyed in user's 'wire' event handler
if (!self.swarm || self.swarm.destroyed) return
if (!self.sentHandshake) self.handshake()
}
Peer.prototype.handshake = function () {
var self = this
var opts = {
dht: self.swarm.private ? false : !!self.swarm.client.dht
}
self.wire.handshake(self.swarm.infoHash, self.swarm.client.peerId, opts)
self.sentHandshake = true
}
Peer.prototype.startConnectTimeout = function () {
var self = this
clearTimeout(self.connectTimeout)
self.connectTimeout = setTimeout(function () {
self.destroy(new Error('connect timeout'))
}, self.type === 'webrtc' ? CONNECT_TIMEOUT_WEBRTC : CONNECT_TIMEOUT_TCP)
if (self.connectTimeout.unref) self.connectTimeout.unref()
}
Peer.prototype.startHandshakeTimeout = function () {
var self = this
clearTimeout(self.handshakeTimeout)
self.handshakeTimeout = setTimeout(function () {
self.destroy(new Error('handshake timeout'))
}, HANDSHAKE_TIMEOUT)
if (self.handshakeTimeout.unref) self.handshakeTimeout.unref()
}
Peer.prototype.destroy = function (err) {
var self = this
if (self.destroyed) return
self.destroyed = true
self.connected = false
debug('destroy %s (error: %s)', self.id, err && (err.message || err))
clearTimeout(self.connectTimeout)
clearTimeout(self.handshakeTimeout)
var swarm = self.swarm
var conn = self.conn
var wire = self.wire
self.swarm = null
self.conn = null
self.wire = null
if (swarm && wire) {
arrayRemove(swarm.wires, swarm.wires.indexOf(wire))
}
if (conn) {
conn.on('error', noop)
conn.destroy()
}
if (wire) wire.destroy()
if (swarm) swarm.removePeer(self.id)
}
function noop () {}
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