chore: do not listen on a relayed conn

src/circuit/auto-relay.js

@@ -11,6 +11,7 @@ const multiaddr = require('multiaddr')
 const { relay: multicodec } = require('./multicodec')
 const { canHop } = require('./circuit/hop')
 
+const circuitProtoCode = 290
 const hopMetadataKey = 'hop_relay'
 const hopMetadataValue = 'true'
 
@@ -72,6 +73,12 @@ class AutoRelay {
     try {
       const connection = this._connectionManager.get(peerId)
 
+      // Do not hop on a relayed connection
+      if (connection.remoteAddr.protoCodes().includes(circuitProtoCode)) {
+        log(`relayed connection to ${id} will not be used to hop on`)
+        return
+      }
+
       await canHop({ connection })
       this._peerStore.metadataBook.set(peerId, hopMetadataKey, uint8ArrayFromString(hopMetadataValue))
       await this._addListenRelay(connection, id)
@@ -180,6 +187,4 @@ class AutoRelay {
   }
 }
 
-// TODO: be careful about relay connect to relay peer that might create a double relayed conn
-
 module.exports = AutoRelay

test/relay/auto-relay.node.js

@@ -223,8 +223,7 @@ describe('auto-relay', () => {
     })
   })
 
-  // TODO: do not allow listen on a relayed connection
-  describe.skip('flows with 2 max listeners', () => {
+  describe('flows with 2 max listeners', () => {
     let relayLibp2p1
     let relayLibp2p2
     let relayLibp2p3
@@ -301,6 +300,13 @@ describe('auto-relay', () => {
       expect(autoRelay2._listenRelays.size).to.equal(1)
 
       // Relay 1 discovers Relay 2 relayed multiaddr via Relay 3
+      const ma2RelayedBy3 = relayLibp2p2.multiaddrs[2]
+      relayLibp2p1.peerStore.addressBook.add(relayLibp2p2.peerId, [ma2RelayedBy3])
+      await relayLibp2p1.dial(relayLibp2p2.peerId)
+
+      // Peer not added as listen relay
+      expect(autoRelay1._addListenRelay.callCount).to.equal(1)
+      expect(autoRelay1._listenRelays.size).to.equal(1)
     })
   })
 })