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328 lines
5.9 KiB
JavaScript

/*!
* proxy-addr
* Copyright(c) 2014-2016 Douglas Christopher Wilson
* MIT Licensed
*/
'use strict'
/**
* Module exports.
* @public
*/
module.exports = proxyaddr
module.exports.all = alladdrs
module.exports.compile = compile
/**
* Module dependencies.
* @private
*/
var forwarded = require('forwarded')
var ipaddr = require('ipaddr.js')
/**
* Variables.
* @private
*/
var DIGIT_REGEXP = /^[0-9]+$/
var isip = ipaddr.isValid
var parseip = ipaddr.parse
/**
* Pre-defined IP ranges.
* @private
*/
var IP_RANGES = {
linklocal: ['169.254.0.0/16', 'fe80::/10'],
loopback: ['127.0.0.1/8', '::1/128'],
uniquelocal: ['10.0.0.0/8', '172.16.0.0/12', '192.168.0.0/16', 'fc00::/7']
}
/**
* Get all addresses in the request, optionally stopping
* at the first untrusted.
*
* @param {Object} request
* @param {Function|Array|String} [trust]
* @public
*/
function alladdrs (req, trust) {
// get addresses
var addrs = forwarded(req)
if (!trust) {
// Return all addresses
return addrs
}
if (typeof trust !== 'function') {
trust = compile(trust)
}
for (var i = 0; i < addrs.length - 1; i++) {
if (trust(addrs[i], i)) continue
addrs.length = i + 1
}
return addrs
}
/**
* Compile argument into trust function.
*
* @param {Array|String} val
* @private
*/
function compile (val) {
if (!val) {
throw new TypeError('argument is required')
}
var trust
if (typeof val === 'string') {
trust = [val]
} else if (Array.isArray(val)) {
trust = val.slice()
} else {
throw new TypeError('unsupported trust argument')
}
for (var i = 0; i < trust.length; i++) {
val = trust[i]
if (!Object.prototype.hasOwnProperty.call(IP_RANGES, val)) {
continue
}
// Splice in pre-defined range
val = IP_RANGES[val]
trust.splice.apply(trust, [i, 1].concat(val))
i += val.length - 1
}
return compileTrust(compileRangeSubnets(trust))
}
/**
* Compile `arr` elements into range subnets.
*
* @param {Array} arr
* @private
*/
function compileRangeSubnets (arr) {
var rangeSubnets = new Array(arr.length)
for (var i = 0; i < arr.length; i++) {
rangeSubnets[i] = parseipNotation(arr[i])
}
return rangeSubnets
}
/**
* Compile range subnet array into trust function.
*
* @param {Array} rangeSubnets
* @private
*/
function compileTrust (rangeSubnets) {
// Return optimized function based on length
var len = rangeSubnets.length
return len === 0
? trustNone
: len === 1
? trustSingle(rangeSubnets[0])
: trustMulti(rangeSubnets)
}
/**
* Parse IP notation string into range subnet.
*
* @param {String} note
* @private
*/
function parseipNotation (note) {
var pos = note.lastIndexOf('/')
var str = pos !== -1
? note.substring(0, pos)
: note
if (!isip(str)) {
throw new TypeError('invalid IP address: ' + str)
}
var ip = parseip(str)
if (pos === -1 && ip.kind() === 'ipv6' && ip.isIPv4MappedAddress()) {
// Store as IPv4
ip = ip.toIPv4Address()
}
var max = ip.kind() === 'ipv6'
? 128
: 32
var range = pos !== -1
? note.substring(pos + 1, note.length)
: null
if (range === null) {
range = max
} else if (DIGIT_REGEXP.test(range)) {
range = parseInt(range, 10)
} else if (ip.kind() === 'ipv4' && isip(range)) {
range = parseNetmask(range)
} else {
range = null
}
if (range <= 0 || range > max) {
throw new TypeError('invalid range on address: ' + note)
}
return [ip, range]
}
/**
* Parse netmask string into CIDR range.
*
* @param {String} netmask
* @private
*/
function parseNetmask (netmask) {
var ip = parseip(netmask)
var kind = ip.kind()
return kind === 'ipv4'
? ip.prefixLengthFromSubnetMask()
: null
}
/**
* Determine address of proxied request.
*
* @param {Object} request
* @param {Function|Array|String} trust
* @public
*/
function proxyaddr (req, trust) {
if (!req) {
throw new TypeError('req argument is required')
}
if (!trust) {
throw new TypeError('trust argument is required')
}
var addrs = alladdrs(req, trust)
var addr = addrs[addrs.length - 1]
return addr
}
/**
* Static trust function to trust nothing.
*
* @private
*/
function trustNone () {
return false
}
/**
* Compile trust function for multiple subnets.
*
* @param {Array} subnets
* @private
*/
function trustMulti (subnets) {
return function trust (addr) {
if (!isip(addr)) return false
var ip = parseip(addr)
var ipconv
var kind = ip.kind()
for (var i = 0; i < subnets.length; i++) {
var subnet = subnets[i]
var subnetip = subnet[0]
var subnetkind = subnetip.kind()
var subnetrange = subnet[1]
var trusted = ip
if (kind !== subnetkind) {
if (subnetkind === 'ipv4' && !ip.isIPv4MappedAddress()) {
// Incompatible IP addresses
continue
}
if (!ipconv) {
// Convert IP to match subnet IP kind
ipconv = subnetkind === 'ipv4'
? ip.toIPv4Address()
: ip.toIPv4MappedAddress()
}
trusted = ipconv
}
if (trusted.match(subnetip, subnetrange)) {
return true
}
}
return false
}
}
/**
* Compile trust function for single subnet.
*
* @param {Object} subnet
* @private
*/
function trustSingle (subnet) {
var subnetip = subnet[0]
var subnetkind = subnetip.kind()
var subnetisipv4 = subnetkind === 'ipv4'
var subnetrange = subnet[1]
return function trust (addr) {
if (!isip(addr)) return false
var ip = parseip(addr)
var kind = ip.kind()
if (kind !== subnetkind) {
if (subnetisipv4 && !ip.isIPv4MappedAddress()) {
// Incompatible IP addresses
return false
}
// Convert IP to match subnet IP kind
ip = subnetisipv4
? ip.toIPv4Address()
: ip.toIPv4MappedAddress()
}
return ip.match(subnetip, subnetrange)
}
}