libp2p: remove mplex

Fixes: #10069

Author: Jorropo

core/node/libp2p/smux.go

@@ -3,7 +3,6 @@ package libp2p
 import (
 	"fmt"
 	"os"
-	"strings"
 
 	"github.com/ipfs/kubo/config"
 
@@ -14,40 +13,16 @@ import (
 
 func makeSmuxTransportOption(tptConfig config.Transports) (libp2p.Option, error) {
 	if prefs := os.Getenv("LIBP2P_MUX_PREFS"); prefs != "" {
-		// Using legacy LIBP2P_MUX_PREFS variable.
-		log.Error("LIBP2P_MUX_PREFS is now deprecated.")
-		log.Error("Use the `Swarm.Transports.Multiplexers' config field.")
-		muxers := strings.Fields(prefs)
-		enabled := make(map[string]bool, len(muxers))
-
-		var opts []libp2p.Option
-		for _, tpt := range muxers {
-			if enabled[tpt] {
-				return nil, fmt.Errorf(
-					"duplicate muxer found in LIBP2P_MUX_PREFS: %s",
-					tpt,
-				)
-			}
-			switch tpt {
-			case yamux.ID:
-				opts = append(opts, libp2p.Muxer(tpt, yamux.DefaultTransport))
-			case mplex.ID:
-				opts = append(opts, libp2p.Muxer(tpt, mplex.DefaultTransport))
-			default:
-				return nil, fmt.Errorf("unknown muxer: %s", tpt)
-			}
-		}
-		return libp2p.ChainOptions(opts...), nil
+		return nil, fmt.Errorf("configuring muxers with LIBP2P_MUX_PREFS is no longer supported, use Swarm.Transports.Multiplexers")
+	}
+	if tptConfig.Multiplexers.Mplex != 0 {
+		return nil, fmt.Errorf("Swarm.Transports.Multiplexers.Mplex is no longer supported, remove it from your config, see https://github.com/libp2p/specs/issues/553")
 	}
-	return prioritizeOptions([]priorityOption{{
-		priority:        tptConfig.Multiplexers.Yamux,
-		defaultPriority: 100,
-		opt:             libp2p.Muxer(yamux.ID, yamux.DefaultTransport),
-	}, {
-		priority:        tptConfig.Multiplexers.Mplex,
-		defaultPriority: config.Disabled,
-		opt:             libp2p.Muxer(mplex.ID, mplex.DefaultTransport),
-	}}), nil
+	if tptConfig.Multiplexers.Yamux < 0 {
+		return nil, fmt.Errorf("running libp2p with Swarm.Transports.Multiplexers.Yamux disabled is not supported")
+	}
+
+	return libp2p.Muxer(yamux.ID, yamux.DefaultTransport), nil
 }
 
 func SmuxTransport(tptConfig config.Transports) func() (opts Libp2pOpts, err error) {

docs/changelogs/v0.25.md

@@ -7,6 +7,7 @@
 - [Overview](#overview)
 - [🔦 Highlights](#-highlights)
   - [RPC `API.Authorizations`](#rpc-apiauthorizations)
+  - [MPLEX removal](#mplex-removal)
   - [Graphsync Experiment Removal](#graphsync-experiment-removal)
 - [📝 Changelog](#-changelog)
 - [👨‍👩‍👧‍👦 Contributors](#-contributors)
@@ -28,6 +29,16 @@ This feature is opt-in. By default, no authorization is set up.
 For configuration instructions,
 refer to the [documentation](https://github.com/ipfs/kubo/blob/master/docs/config.md#apiauthorizations).
 
+#### MPLEX Removal
+
+After deprecating and removing mplex support by default in [v0.23.0](https://github.com/ipfs/kubo/blob/master/docs/changelogs/v0.23.md#mplex-deprecation).
+
+We now fully removed it. If you still need mplex support to talk with other pieces of software,
+please try updating them, and if they don't support yamux or QUIC talk to us about it.
+
+Mplex is unreliable by design, it will drop data and generete errors when sending data *too fast*,
+yamux and QUIC support backpressure, that means if we send data faster than the remote machine can process it, we slows down to match the remote's speed.
+
 #### Graphsync Experiment Removal
 
 Currently the Graphsync server is to our knowledge not used

docs/config.md

@@ -2253,21 +2253,10 @@ Type: `priority`
 
 ### `Swarm.Transports.Multiplexers.Mplex`
 
-**DEPRECATED**: See https://github.com/ipfs/kubo/issues/9958
+**REMOVED**: See https://github.com/ipfs/kubo/issues/9958
 
-Mplex is deprecated, this is because it is unreliable and
-randomly drop streams when sending data *too fast*.
-
-New pieces of code rely on backpressure, that means the stream will dynamically
-slow down the sending rate if data is getting backed up.
-Backpressure is provided by **Yamux** and **QUIC**.
-
-If you want to turn it back on make sure to have a higher (lower is better)
-priority than `Yamux`, you don't want your Kubo to start defaulting to Mplex.
-
-Default: `200`
-
-Type: `priority`
+Support for Mplex has been [removed from Kubo and go-libp2p](https://github.com/libp2p/specs/issues/553).
+Please remove this option from your config.
 
 ## `DNS`
 

test/cli/transports_test.go

@@ -72,20 +72,6 @@ func TestTransports(t *testing.T) {
 		runTests(nodes)
 	})
 
-	t.Run("tcp with mplex", func(t *testing.T) {
-		// FIXME(#10069): we don't want this to exists anymore
-		t.Parallel()
-		nodes := tcpNodes(t)
-		nodes.ForEachPar(func(n *harness.Node) {
-			n.UpdateConfig(func(cfg *config.Config) {
-				cfg.Swarm.Transports.Multiplexers.Yamux = config.Disabled
-				cfg.Swarm.Transports.Multiplexers.Mplex = 200
-			})
-		})
-		nodes.StartDaemons().Connect()
-		runTests(nodes)
-	})
-
 	t.Run("tcp with NOISE", func(t *testing.T) {
 		t.Parallel()
 		nodes := tcpNodes(t)