feat: add multiaddr filter function (#305)

related to libp2p/js-libp2p#1510

---------

Co-authored-by: Alex Potsides <alex@achingbrain.net>

package.json

@@ -166,6 +166,7 @@
   },
   "dependencies": {
     "@chainsafe/is-ip": "^2.0.1",
+    "@chainsafe/netmask": "^2.0.0",
     "dns-over-http-resolver": "^2.1.0",
     "err-code": "^3.0.1",
     "multiformats": "^11.0.0",
@@ -175,8 +176,7 @@
   "devDependencies": {
     "@types/varint": "^6.0.0",
     "aegir": "^38.1.0",
-    "sinon": "^15.0.0",
-    "util": "^0.12.3"
+    "sinon": "^15.0.0"
   },
   "browser": {
     "./dist/src/resolvers/dns.js": "./dist/src/resolvers/dns.browser.js"

src/convert.ts

@@ -15,6 +15,12 @@ import varint from 'varint'
 import { toString as uint8ArrayToString } from 'uint8arrays/to-string'
 import { fromString as uint8ArrayFromString } from 'uint8arrays/from-string'
 import { concat as uint8ArrayConcat } from 'uint8arrays/concat'
+import type { Multiaddr } from './index.js'
+import { IpNet } from '@chainsafe/netmask'
+
+const ip4Protocol = getProtocol('ip4')
+const ip6Protocol = getProtocol('ip6')
+const ipcidrProtocol = getProtocol('ipcidr')
 
 /**
  * converts (serializes) addresses
@@ -107,6 +113,23 @@ export function convertToBytes (proto: string | number, str: string): Uint8Array
   }
 }
 
+export function convertToIpNet (multiaddr: Multiaddr): IpNet {
+  let mask: string | undefined
+  let addr: string | undefined
+  multiaddr.stringTuples().forEach(([code, value]) => {
+    if (code === ip4Protocol.code || code === ip6Protocol.code) {
+      addr = value
+    }
+    if (code === ipcidrProtocol.code) {
+      mask = value
+    }
+  })
+  if (mask == null || addr == null) {
+    throw new Error('Invalid multiaddr')
+  }
+  return new IpNet(addr, mask)
+}
+
 const decoders = Object.values(bases).map((c) => c.decoder)
 const anybaseDecoder = (function () {
   let acc = decoders[0].or(decoders[1])

src/filter/multiaddr-filter.ts

@@ -0,0 +1,46 @@
+import type { IpNet } from '@chainsafe/netmask'
+import { convertToIpNet } from '../convert.js'
+import { multiaddr, Multiaddr, MultiaddrInput } from '../index.js'
+
+/**
+ * A utility class to determine if a Multiaddr contains another
+ * multiaddr.
+ *
+ * This can be used with ipcidr ranges to determine if a given
+ * multiaddr is in a ipcidr range.
+ *
+ * @example
+ *
+ * ```js
+ * import { multiaddr, MultiaddrFilter } from '@multiformats/multiaddr'
+ *
+ * const range = multiaddr('/ip4/192.168.10.10/ipcidr/24')
+ * const filter = new MultiaddrFilter(range)
+ *
+ * const input = multiaddr('/ip4/192.168.10.2/udp/60')
+ * console.info(filter.contains(input)) // true
+ * ```
+ */
+export class MultiaddrFilter {
+  private readonly multiaddr: Multiaddr
+  private readonly netmask: IpNet
+
+  public constructor (input: MultiaddrInput) {
+    this.multiaddr = multiaddr(input)
+    this.netmask = convertToIpNet(this.multiaddr)
+  }
+
+  public contains (input: MultiaddrInput): boolean {
+    if (input == null) return false
+    const m = multiaddr(input)
+    let ip
+    for (const [code, value] of m.stringTuples()) {
+      if (code === 4 || code === 41) {
+        ip = value
+        break
+      }
+    }
+    if (ip === undefined) return false
+    return this.netmask.contains(ip)
+  }
+}

src/index.ts

@@ -94,6 +94,8 @@ export interface AbortOptions {
 export const resolvers = new Map<string, Resolver>()
 const symbol = Symbol.for('@multiformats/js-multiaddr/multiaddr')
 
+export { MultiaddrFilter } from './filter/multiaddr-filter.js'
+
 export interface Multiaddr {
   bytes: Uint8Array
 

test/convert.spec.ts

@@ -2,6 +2,7 @@
 import * as convert from '../src/convert.js'
 import { expect } from 'aegir/chai'
 import { fromString as uint8ArrayFromString } from 'uint8arrays/from-string'
+import { multiaddr } from '../src/index.js'
 
 describe('convert', () => {
   it('handles ip4 buffers', () => {
@@ -100,4 +101,22 @@ describe('convert', () => {
     const bytesOut = convert.convertToBytes(466, outcome)
     expect(bytesOut.toString()).to.equal(bytes.toString())
   })
+
+  it('convertToIpNet ip4', function () {
+    const ipnet = convert.convertToIpNet(multiaddr('/ip4/192.0.2.0/ipcidr/24'))
+    expect(ipnet.toString()).equal('192.0.2.0/24')
+  })
+
+  it('convertToIpNet ip6', function () {
+    const ipnet = convert.convertToIpNet(multiaddr('/ip6/2001:0db8:85a3:0000:0000:8a2e:0370:7334/ipcidr/64'))
+    expect(ipnet.toString()).equal('2001:0db8:85a3:0000:0000:0000:0000:0000/64')
+  })
+
+  it('convertToIpNet not ipcidr', function () {
+    expect(() => convert.convertToIpNet(multiaddr('/ip6/2001:0db8:85a3:0000:0000:8a2e:0370:7334/tcp/64'))).to.throw()
+  })
+
+  it('convertToIpNet not ipv6', function () {
+    expect(() => convert.convertToIpNet(multiaddr('/dns6/foo.com/ipcidr/64'))).to.throw()
+  })
 })

test/filter/multiaddr-filter.spec.ts

@@ -0,0 +1,25 @@
+/* eslint-env mocha */
+import { expect } from 'aegir/chai'
+import { MultiaddrFilter, multiaddr, MultiaddrInput } from '../../src/index.js'
+
+describe('MultiaddrFilter', () => {
+  const cases: Array<[MultiaddrInput, MultiaddrInput, boolean]> = [
+    ['/ip4/192.168.10.10/ipcidr/24', '/ip4/192.168.10.2/tcp/60', true],
+    [multiaddr('/ip4/192.168.10.10/ipcidr/24'), '/ip4/192.168.10.2/tcp/60', true],
+    [multiaddr('/ip4/192.168.10.10/ipcidr/24').bytes, '/ip4/192.168.10.2/tcp/60', true],
+    ['/ip4/192.168.10.10/ipcidr/24', '/ip4/192.168.10.2/udp/60', true],
+    ['/ip4/192.168.10.10/ipcidr/24', multiaddr('/ip4/192.168.11.2/tcp/60'), false],
+    ['/ip4/192.168.10.10/ipcidr/24', null, false],
+    ['/ip4/192.168.10.10/ipcidr/24', multiaddr('/ip4/192.168.11.2/udp/60').bytes, false],
+    ['/ip4/192.168.10.10/ipcidr/24', '/ip4/192.168.11.2/udp/60', false],
+    ['/ip4/192.168.10.10/ipcidr/24', '/ip6/2001:db8:3333:4444:5555:6666:7777:8888/tcp/60', false],
+    ['/ip6/2001:db8:3333:4444:5555:6666:7777:8888/ipcidr/60', '/ip6/2001:0db8:3333:4440:0000:0000:0000:0000/tcp/60', true],
+    ['/ip6/2001:db8:3333:4444:5555:6666:7777:8888/ipcidr/60', '/ip6/2001:0db8:3333:4450:0000:0000:0000:0000/tcp/60', false]
+  ]
+
+  cases.forEach(([cidr, ip, result]) => {
+    it(`multiaddr filter cidr=${cidr} ip=${ip} result=${String(result)}`, function () {
+      expect(new MultiaddrFilter(cidr).contains(ip)).to.be.equal(result)
+    })
+  })
+})