fix: use optimistic protocol negotation (libp2p#2253)

When negotiating connection encrypters, multiplexers or stream protocols, if we only have one protocol to negotiate there's no point sending it, then waiting for a response, then sending some data, we can just send it, and the data, then assuming the remote doesn't immediately close the negotiation channel, read the response at our leisure.

This saves a round trip for the first chunk of stream data and reduces our connection latency in the [libp2p perf tests](https://observablehq.com/@libp2p-workspace/performance-dashboard?branch=c8022cb77397759bd7e71a73e93f9074854989fe) from 0.45 to 0.3ms.

It changes stream behaviour a little, since we now don't start the protocol negotiation until we interact with the stream (e.g. try to read or write data) and most of our tests assume that negotiation has succeeded when the stream is returned so it's not been a straightforward fix.

packages/integration-tests/test/circuit-relay.node.ts

@@ -522,7 +522,7 @@ describe('circuit-relay', () => {
       expect(conns).to.have.lengthOf(1)
 
       // this should fail as the local peer has HOP disabled
-      await expect(conns[0].newStream(RELAY_V2_HOP_CODEC))
+      await expect(conns[0].newStream([RELAY_V2_HOP_CODEC, '/other/1.0.0']))
         .to.be.rejected()
 
       // we should still be connected to the relay

packages/interface-compliance-tests/src/pubsub/two-nodes.ts

@@ -73,7 +73,7 @@ export default (common: TestSetup<PubSub, PubSubArgs>): void => {
         expect(psA.getTopics()).to.deep.equal([topic])
         expect(psB.getPeers()).to.have.lengthOf(1)
         expect(psB.getSubscribers(topic).map(p => p.toString())).to.deep.equal([componentsA.peerId.toString()])
-        expect(changedPeerId).to.deep.equal(psB.getPeers()[0])
+        expect(changedPeerId.toString()).to.equal(psB.getPeers()[0].toString())
         expect(changedSubs).to.have.lengthOf(1)
         expect(changedSubs[0].topic).to.equal(topic)
         expect(changedSubs[0].subscribe).to.equal(true)
@@ -243,7 +243,7 @@ export default (common: TestSetup<PubSub, PubSubArgs>): void => {
           const { peerId: changedPeerId, subscriptions: changedSubs } = evt.detail
           expect(psB.getPeers()).to.have.lengthOf(1)
           expect(psB.getTopics()).to.be.empty()
-          expect(changedPeerId).to.deep.equal(psB.getPeers()[0])
+          expect(changedPeerId.toString()).to.equal(psB.getPeers()[0].toString())
           expect(changedSubs).to.have.lengthOf(1)
           expect(changedSubs[0].topic).to.equal(topic)
           expect(changedSubs[0].subscribe).to.equal(true)
@@ -252,7 +252,7 @@ export default (common: TestSetup<PubSub, PubSubArgs>): void => {
           const { peerId: changedPeerId, subscriptions: changedSubs } = evt.detail
           expect(psB.getPeers()).to.have.lengthOf(1)
           expect(psB.getTopics()).to.be.empty()
-          expect(changedPeerId).to.deep.equal(psB.getPeers()[0])
+          expect(changedPeerId.toString()).to.equal(psB.getPeers()[0].toString())
           expect(changedSubs).to.have.lengthOf(1)
           expect(changedSubs[0].topic).to.equal(topic)
           expect(changedSubs[0].subscribe).to.equal(false)

packages/libp2p/.aegir.js

@@ -18,6 +18,7 @@ export default {
       const { plaintext } = await import('@libp2p/plaintext')
       const { circuitRelayServer, circuitRelayTransport } = await import('@libp2p/circuit-relay-v2')
       const { identify } = await import('@libp2p/identify')
+      const { echo, ECHO_PROTOCOL } = await import('./dist/test/fixtures/echo-service.js')
 
       const peerId = await createEd25519PeerId()
       const libp2p = await createLibp2p({
@@ -49,14 +50,10 @@ export default {
             reservations: {
               maxReservations: Infinity
             }
-          })
+          }),
+          echo: echo()
         }
       })
-      // Add the echo protocol
-      await libp2p.handle('/echo/1.0.0', ({ stream }) => {
-        pipe(stream, stream)
-          .catch() // sometimes connections are closed before multistream-select finishes which causes an error
-      })
 
       return {
         libp2p,

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

@@ -461,7 +461,7 @@ export class DialQueue {
       // internal peer dial queue - only one dial per peer at a time
       const peerDialQueue = new PQueue({ concurrency: 1 })
       peerDialQueue.on('error', (err) => {
-        this.log.error('error dialing [%s] %o', pendingDial.multiaddrs, err)
+        this.log.error('error dialing %s %o', pendingDial.multiaddrs, err)
       })
 
       const conn = await Promise.any(pendingDial.multiaddrs.map(async (addr, i) => {

packages/libp2p/src/upgrader.ts

@@ -117,14 +117,12 @@ export class DefaultUpgrader implements Upgrader {
   private readonly muxers: Map<string, StreamMuxerFactory>
   private readonly inboundUpgradeTimeout: number
   private readonly events: TypedEventTarget<Libp2pEvents>
-  private readonly logger: ComponentLogger
   private readonly log: Logger
 
   constructor (components: DefaultUpgraderComponents, init: UpgraderInit) {
     this.components = components
     this.connectionEncryption = new Map()
     this.log = components.logger.forComponent('libp2p:upgrader')
-    this.logger = components.logger
 
     init.connectionEncryption.forEach(encrypter => {
       this.connectionEncryption.set(encrypter.protocol, encrypter)
@@ -415,6 +413,21 @@ export class DefaultUpgrader implements Upgrader {
               muxedStream.sink = stream.sink
               muxedStream.protocol = protocol
 
+              // allow closing the write end of a not-yet-negotiated stream
+              if (stream.closeWrite != null) {
+                muxedStream.closeWrite = stream.closeWrite
+              }
+
+              // allow closing the read end of a not-yet-negotiated stream
+              if (stream.closeRead != null) {
+                muxedStream.closeRead = stream.closeRead
+              }
+
+              // make sure we don't try to negotiate a stream we are closing
+              if (stream.close != null) {
+                muxedStream.close = stream.close
+              }
+
               // If a protocol stream has been successfully negotiated and is to be passed to the application,
               // the peerstore should ensure that the peer is registered with that protocol
               await this.components.peerStore.merge(remotePeer, {
@@ -426,7 +439,7 @@ export class DefaultUpgrader implements Upgrader {
               this._onStream({ connection, stream: muxedStream, protocol })
             })
             .catch(async err => {
-              this.log.error('error handling incoming stream id %d', muxedStream.id, err.message, err.code, err.stack)
+              this.log.error('error handling incoming stream id %s', muxedStream.id, err.message, err.code, err.stack)
 
               if (muxedStream.timeline.close == null) {
                 await muxedStream.close()
@@ -440,13 +453,13 @@ export class DefaultUpgrader implements Upgrader {
           throw new CodeError('Stream is not multiplexed', codes.ERR_MUXER_UNAVAILABLE)
         }
 
-        connection.log('starting new stream for protocols [%s]', protocols)
+        connection.log('starting new stream for protocols %s', protocols)
         const muxedStream = await muxer.newStream()
-        connection.log.trace('starting new stream %s for protocols [%s]', muxedStream.id, protocols)
+        connection.log.trace('started new stream %s for protocols %s', muxedStream.id, protocols)
 
         try {
           if (options.signal == null) {
-            this.log('No abort signal was passed while trying to negotiate protocols [%s] falling back to default timeout', protocols)
+            this.log('No abort signal was passed while trying to negotiate protocols %s falling back to default timeout', protocols)
 
             const signal = AbortSignal.timeout(DEFAULT_PROTOCOL_SELECT_TIMEOUT)
             setMaxListeners(Infinity, signal)
@@ -457,13 +470,18 @@ export class DefaultUpgrader implements Upgrader {
             }
           }
 
-          const { stream, protocol } = await mss.select(muxedStream, protocols, {
+          muxedStream.log.trace('selecting protocol from protocols %s', protocols)
+
+          const {
+            stream,
+            protocol
+          } = await mss.select(muxedStream, protocols, {
             ...options,
             log: muxedStream.log,
-            yieldBytes: false
+            yieldBytes: true
           })
 
-          connection.log('negotiated protocol stream %s with id %s', protocol, muxedStream.id)
+          muxedStream.log('selected protocol %s', protocol)
 
           const outgoingLimit = findOutgoingStreamLimit(protocol, this.components.registrar, options)
           const streamCount = countStreams(protocol, 'outbound', connection)
@@ -487,6 +505,21 @@ export class DefaultUpgrader implements Upgrader {
           muxedStream.sink = stream.sink
           muxedStream.protocol = protocol
 
+          // allow closing the write end of a not-yet-negotiated stream
+          if (stream.closeWrite != null) {
+            muxedStream.closeWrite = stream.closeWrite
+          }
+
+          // allow closing the read end of a not-yet-negotiated stream
+          if (stream.closeRead != null) {
+            muxedStream.closeRead = stream.closeRead
+          }
+
+          // make sure we don't try to negotiate a stream we are closing
+          if (stream.close != null) {
+            muxedStream.close = stream.close
+          }
+
           this.components.metrics?.trackProtocolStream(muxedStream, connection)
 
           return muxedStream
@@ -637,16 +670,23 @@ export class DefaultUpgrader implements Upgrader {
     this.log('selecting outbound crypto protocol', protocols)
 
     try {
-      const { stream, protocol } = await mss.select(connection, protocols, {
-        log: this.logger.forComponent('libp2p:mss:select')
+      connection.log.trace('selecting encrypter from %s', protocols)
+
+      const {
+        stream,
+        protocol
+      } = await mss.select(connection, protocols, {
+        log: connection.log,
+        yieldBytes: true
       })
+
       const encrypter = this.connectionEncryption.get(protocol)
 
       if (encrypter == null) {
         throw new Error(`no crypto module found for ${protocol}`)
       }
 
-      this.log('encrypting outbound connection to %p', remotePeerId)
+      connection.log('encrypting outbound connection to %p using %p', remotePeerId)
 
       return {
         ...await encrypter.secureOutbound(this.components.peerId, stream, remotePeerId),
@@ -665,15 +705,22 @@ export class DefaultUpgrader implements Upgrader {
     const protocols = Array.from(muxers.keys())
     this.log('outbound selecting muxer %s', protocols)
     try {
-      const { stream, protocol } = await mss.select(connection, protocols, {
-        log: this.logger.forComponent('libp2p:mss:select')
+      connection.log.trace('selecting stream muxer from %s', protocols)
+
+      const {
+        stream,
+        protocol
+      } = await mss.select(connection, protocols, {
+        log: connection.log,
+        yieldBytes: true
       })
-      this.log('%s selected as muxer protocol', protocol)
+
+      connection.log('selected %s as muxer protocol', protocol)
       const muxerFactory = muxers.get(protocol)
 
       return { stream, muxerFactory }
     } catch (err: any) {
-      this.log.error('error multiplexing outbound stream', err)
+      connection.log.error('error multiplexing outbound stream', err)
       throw new CodeError(String(err), codes.ERR_MUXER_UNAVAILABLE)
     }
   }

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

@@ -33,6 +33,7 @@ import { DefaultConnectionManager } from '../../src/connection-manager/index.js'
 import { codes as ErrorCodes } from '../../src/errors.js'
 import { createLibp2pNode, type Libp2pNode } from '../../src/libp2p.js'
 import { DefaultTransportManager } from '../../src/transport-manager.js'
+import { ECHO_PROTOCOL, echo } from '../fixtures/echo-service.js'
 import type { PeerId } from '@libp2p/interface/peer-id'
 import type { TransportManager } from '@libp2p/interface-internal/transport-manager'
 import type { Multiaddr } from '@multiformats/multiaddr'
@@ -303,10 +304,10 @@ describe('libp2p.dialer (direct, TCP)', () => {
       ],
       connectionEncryption: [
         plaintext()
-      ]
-    })
-    await remoteLibp2p.handle('/echo/1.0.0', ({ stream }) => {
-      void pipe(stream, stream)
+      ],
+      services: {
+        echo: echo()
+      }
     })
 
     await remoteLibp2p.start()
@@ -348,9 +349,9 @@ describe('libp2p.dialer (direct, TCP)', () => {
 
     const connection = await libp2p.dial(remotePeerId)
     expect(connection).to.exist()
-    const stream = await connection.newStream('/echo/1.0.0')
+    const stream = await connection.newStream(ECHO_PROTOCOL)
     expect(stream).to.exist()
-    expect(stream).to.have.property('protocol', '/echo/1.0.0')
+    expect(stream).to.have.property('protocol', ECHO_PROTOCOL)
     await connection.close()
   })
 
@@ -388,7 +389,7 @@ describe('libp2p.dialer (direct, TCP)', () => {
     const connection = await libp2p.dial(remoteLibp2p.getMultiaddrs())
 
     // Create local to remote streams
-    const stream = await connection.newStream('/echo/1.0.0')
+    const stream = await connection.newStream([ECHO_PROTOCOL, '/other/1.0.0'])
     await connection.newStream('/stream-count/3')
     await libp2p.dialProtocol(remoteLibp2p.peerId, '/stream-count/4')
 
@@ -398,8 +399,8 @@ describe('libp2p.dialer (direct, TCP)', () => {
     source.push(uint8ArrayFromString('hello'))
 
     // Create remote to local streams
-    await remoteLibp2p.dialProtocol(libp2p.peerId, '/stream-count/1')
-    await remoteLibp2p.dialProtocol(libp2p.peerId, '/stream-count/2')
+    await remoteLibp2p.dialProtocol(libp2p.peerId, ['/stream-count/1', '/other/1.0.0'])
+    await remoteLibp2p.dialProtocol(libp2p.peerId, ['/stream-count/2', '/other/1.0.0'])
 
     // Verify stream count
     const remoteConn = remoteLibp2p.getConnections(libp2p.peerId)
@@ -497,9 +498,9 @@ describe('libp2p.dialer (direct, TCP)', () => {
 
     const connection = await libp2p.dial(remoteAddr)
     expect(connection).to.exist()
-    const stream = await connection.newStream('/echo/1.0.0')
+    const stream = await connection.newStream(ECHO_PROTOCOL)
     expect(stream).to.exist()
-    expect(stream).to.have.property('protocol', '/echo/1.0.0')
+    expect(stream).to.have.property('protocol', ECHO_PROTOCOL)
     await connection.close()
     expect(protectorProtectSpy.callCount).to.equal(1)
   })

packages/libp2p/test/connection-manager/index.node.ts

@@ -5,6 +5,8 @@ import { start } from '@libp2p/interface/startable'
 import { mockConnection, mockDuplex, mockMultiaddrConnection } from '@libp2p/interface-compliance-tests/mocks'
 import { expect } from 'aegir/chai'
 import delay from 'delay'
+import all from 'it-all'
+import { pipe } from 'it-pipe'
 import pWaitFor from 'p-wait-for'
 import sinon from 'sinon'
 import { stubInterface } from 'sinon-ts'
@@ -13,6 +15,7 @@ import { DefaultConnectionManager } from '../../src/connection-manager/index.js'
 import { codes } from '../../src/errors.js'
 import { createBaseOptions } from '../fixtures/base-options.browser.js'
 import { createNode, createPeerId } from '../fixtures/creators/peer.js'
+import { ECHO_PROTOCOL, echo } from '../fixtures/echo-service.js'
 import type { Libp2p } from '../../src/index.js'
 import type { Libp2pNode } from '../../src/libp2p.js'
 import type { ConnectionGater } from '@libp2p/interface/connection-gater'
@@ -401,6 +404,9 @@ describe('libp2p.connections', () => {
           peerId: peerIds[1],
           addresses: {
             listen: ['/ip4/127.0.0.1/tcp/0/ws']
+          },
+          services: {
+            echo: echo()
           }
         })
       })
@@ -591,16 +597,23 @@ describe('libp2p.connections', () => {
           },
           connectionGater: {
             denyInboundUpgradedConnection
+          },
+          services: {
+            echo: echo()
           }
         })
       })
       await remoteLibp2p.peerStore.patch(libp2p.peerId, {
         multiaddrs: libp2p.getMultiaddrs()
       })
-      await remoteLibp2p.dial(libp2p.peerId)
+      const connection = await remoteLibp2p.dial(libp2p.peerId)
+      const stream = await connection.newStream(ECHO_PROTOCOL)
+      const input = [Uint8Array.from([0])]
+      const output = await pipe(input, stream, async (source) => all(source))
 
       expect(denyInboundUpgradedConnection.called).to.be.true()
       expect(denyInboundUpgradedConnection.getCall(0)).to.have.nested.property('args[0].multihash.digest').that.equalBytes(remoteLibp2p.peerId.multihash.digest)
+      expect(output.map(b => b.subarray())).to.deep.equal(input)
     })
 
     it('intercept outbound upgraded', async () => {
@@ -620,10 +633,14 @@ describe('libp2p.connections', () => {
       await libp2p.peerStore.patch(remoteLibp2p.peerId, {
         multiaddrs: remoteLibp2p.getMultiaddrs()
       })
-      await libp2p.dial(remoteLibp2p.peerId)
+      const connection = await libp2p.dial(remoteLibp2p.peerId)
+      const stream = await connection.newStream(ECHO_PROTOCOL)
+      const input = [Uint8Array.from([0])]
+      const output = await pipe(input, stream, async (source) => all(source))
 
       expect(denyOutboundUpgradedConnection.called).to.be.true()
       expect(denyOutboundUpgradedConnection.getCall(0)).to.have.nested.property('args[0].multihash.digest').that.equalBytes(remoteLibp2p.peerId.multihash.digest)
+      expect(output.map(b => b.subarray())).to.deep.equal(input)
     })
   })
 })

packages/libp2p/test/content-routing/dht/utils.ts

@@ -1,3 +1,4 @@
 export const subsystemMulticodecs = [
-  '/ipfs/lan/kad/1.0.0'
+  '/ipfs/lan/kad/1.0.0',
+  '/other/1.0.0'
 ]