test: add TestTcpTransportWithLinkLocalAddress

p2p/transport/tcp/tcp_test.go

@@ -3,6 +3,7 @@ package tcp
 import (
 	"context"
 	"errors"
+	"net"
 	"testing"
 
 	"github.com/libp2p/go-libp2p/core/crypto"
@@ -46,6 +47,57 @@ func TestTcpTransport(t *testing.T) {
 	envReuseportVal = true
 }
 
+func TestTcpTransportWithLinkLocalAddress(t *testing.T) {
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	var targetAddr ma.Multiaddr
+
+findInterface:
+	for _, iface := range ifaces {
+		addrs, err := iface.Addrs()
+		if err == nil {
+			for _, a := range addrs {
+				addr, err := manet.FromNetAddr(a)
+				if err == nil {
+					if manet.IsIP6LinkLocal(addr) {
+						targetAddr = ma.StringCast("/ip6zone/" + iface.Name + addr.String())
+						break findInterface
+					}
+				}
+			}
+		}
+	}
+
+	if targetAddr == nil {
+		t.Fail()
+		return
+	}
+
+	for i := 0; i < 2; i++ {
+		peerA, ia := makeInsecureMuxer(t)
+		_, ib := makeInsecureMuxer(t)
+
+		ua, err := tptu.New(ia, muxers, nil, nil, nil)
+		require.NoError(t, err)
+		ta, err := NewTCPTransport(ua, nil)
+		require.NoError(t, err)
+		ub, err := tptu.New(ib, muxers, nil, nil, nil)
+		require.NoError(t, err)
+		tb, err := NewTCPTransport(ub, nil)
+		require.NoError(t, err)
+
+		zero := targetAddr.String() + "/tcp/0"
+		ttransport.SubtestTransport(t, ta, tb, zero, peerA)
+
+		envReuseportVal = false
+	}
+	envReuseportVal = true
+}
+
 func TestTcpTransportWithMetrics(t *testing.T) {
 	peerA, ia := makeInsecureMuxer(t)
 	_, ib := makeInsecureMuxer(t)