fix(libp2p): filter out dnsaddrs for different peers (#1954)

Some multiaddrs like `/dnsaddr/bootstrap.ipfs.io` resolve to multiple
PeerIds.

E.g:

```console
% dig _dnsaddr.bootstrap.libp2p.io TXT

; <<>> DiG 9.10.6 <<>> _dnsaddr.bootstrap.libp2p.io TXT
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 53473
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;_dnsaddr.bootstrap.libp2p.io.	IN	TXT

;; ANSWER SECTION:
_dnsaddr.bootstrap.libp2p.io. 261 IN	TXT	"dnsaddr=/dnsaddr/am6.bootstrap.libp2p.io/p2p/QmbLHAnMoJPWSCR5Zhtx6BHJX9KiKNN6tpvbUcqanj75Nb"
_dnsaddr.bootstrap.libp2p.io. 261 IN	TXT	"dnsaddr=/dnsaddr/ny5.bootstrap.libp2p.io/p2p/QmQCU2EcMqAqQPR2i9bChDtGNJchTbq5TbXJJ16u19uLTa"
_dnsaddr.bootstrap.libp2p.io. 261 IN	TXT	"dnsaddr=/dnsaddr/sg1.bootstrap.libp2p.io/p2p/QmcZf59bWwK5XFi76CZX8cbJ4BhTzzA3gU1ZjYZcYW3dwt"
_dnsaddr.bootstrap.libp2p.io. 261 IN	TXT	"dnsaddr=/dnsaddr/sv15.bootstrap.libp2p.io/p2p/QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN"
```

This can cause problems when dialing those addresses with a PeerId
since resolving the dnsaddr returns addresses with embedded PeerIds
that aren't for the node you are trying to dial so filter those out.

The errors these cause are non-fatal but do consume resources dialing
nodes we aren't going to be able to connect to.

Author: achingbrain

packages/libp2p/src/connection-manager/dial-queue.ts

@@ -309,8 +309,22 @@ export class DialQueue {
     ))
       .flat()
 
-    // filter out any multiaddrs that we do not have transports for
-    const filteredAddrs = resolvedAddresses.filter(addr => Boolean(this.transportManager.transportForMultiaddr(addr.multiaddr)))
+    const filteredAddrs = resolvedAddresses.filter(addr => {
+      // filter out any multiaddrs that we do not have transports for
+      if (this.transportManager.transportForMultiaddr(addr.multiaddr) == null) {
+        return false
+      }
+
+      // if the resolved multiaddr has a PeerID but it's the wrong one, ignore it
+      // - this can happen with addresses like bootstrap.libp2p.io that resolve
+      // to multiple different peers
+      const addrPeerId = addr.multiaddr.getPeerId()
+      if (peerId != null && addrPeerId != null) {
+        return peerId.equals(addrPeerId)
+      }
+
+      return true
+    })
 
     // deduplicate addresses
     const dedupedAddrs = new Map<string, Address>()

packages/libp2p/test/connection-manager/dial-queue.spec.ts

@@ -2,7 +2,7 @@
 
 import { mockConnection, mockDuplex, mockMultiaddrConnection } from '@libp2p/interface-compliance-tests/mocks'
 import { createEd25519PeerId } from '@libp2p/peer-id-factory'
-import { multiaddr } from '@multiformats/multiaddr'
+import { multiaddr, resolvers } from '@multiformats/multiaddr'
 import { expect } from 'aegir/chai'
 import delay from 'delay'
 import pDefer from 'p-defer'
@@ -280,4 +280,52 @@ describe('dial queue', () => {
     // Dial attempt finished without connection
     expect(signals['/ip4/127.0.0.1/tcp/1233']).to.have.property('aborted', true)
   })
+
+  it('should ignore DNS addresses for other peers', async () => {
+    const remotePeer = await createEd25519PeerId()
+    const otherRemotePeer = await createEd25519PeerId()
+    const ma = multiaddr(`/dnsaddr/example.com/p2p/${remotePeer}`)
+    const maStr = `/ip4/123.123.123.123/tcp/2348/p2p/${remotePeer}`
+    const resolvedAddresses = [
+      `/ip4/234.234.234.234/tcp/4213/p2p/${otherRemotePeer}`,
+      maStr
+    ]
+
+    let resolvedDNSAddrs = false
+    let dialedBadAddress = false
+
+    // simulate a DNSAddr that resolves to multiple different peers like
+    // bootstrap.libp2p.io
+    resolvers.set('dnsaddr', async (addr) => {
+      if (addr.equals(ma)) {
+        resolvedDNSAddrs = true
+        return resolvedAddresses
+      }
+
+      return []
+    })
+
+    dialer = new DialQueue(components, {
+      maxParallelDials: 50
+    })
+    components.transportManager.transportForMultiaddr.returns(stubInterface<Transport>())
+
+    const connection = mockConnection(mockMultiaddrConnection(mockDuplex(), remotePeer))
+
+    components.transportManager.dial.callsFake(async (ma, opts = {}) => {
+      if (ma.toString() === maStr) {
+        await delay(100)
+        return connection
+      }
+
+      dialedBadAddress = true
+      throw new Error('Could not dial address')
+    })
+
+    await expect(dialer.dial(ma)).to.eventually.equal(connection)
+    expect(resolvedDNSAddrs).to.be.true('Did not resolve DNSAddrs')
+    expect(dialedBadAddress).to.be.false('Dialed address with wrong peer id')
+
+    resolvers.delete('dnsaddr')
+  })
 })

packages/libp2p/test/connection-manager/direct.spec.ts

@@ -165,7 +165,7 @@ describe('dialing (direct, WebSockets)', () => {
 
     const remotePeerId = peerIdFromString(remoteAddr.getPeerId() ?? '')
     await localComponents.peerStore.patch(remotePeerId, {
-      multiaddrs: Array.from({ length: 11 }, (_, i) => multiaddr(`/ip4/127.0.0.1/tcp/1500${i}/ws/p2p/12D3KooWHFKTMzwerBtsVmtz4ZZEQy2heafxzWw6wNn5PPYkBxJ5`))
+      multiaddrs: Array.from({ length: 11 }, (_, i) => multiaddr(`/ip4/127.0.0.1/tcp/1500${i}/ws/p2p/${remotePeerId.toString()}`))
     })
 
     await expect(connectionManager.openConnection(remotePeerId))