Update

vendor/tailscale.com/net/memnet/memnet.go

@@ -6,3 +6,87 @@
 // in tests and other situations where you don't want to use the
 // network.
 package memnet
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/netip"
+
+	"tailscale.com/net/netx"
+	"tailscale.com/syncs"
+)
+
+var _ netx.Network = (*Network)(nil)
+
+// Network implements [Network] using an in-memory network, usually
+// used for testing.
+//
+// As of 2025-04-08, it only supports TCP.
+//
+// Its zero value is a valid [netx.Network] implementation.
+type Network struct {
+	mu  syncs.Mutex
+	lns map[string]*Listener // address -> listener
+}
+
+func (m *Network) Listen(network, address string) (net.Listener, error) {
+	if network != "tcp" && network != "tcp4" && network != "tcp6" {
+		return nil, fmt.Errorf("memNetwork: Listen called with unsupported network %q", network)
+	}
+	ap, err := netip.ParseAddrPort(address)
+	if err != nil {
+		return nil, fmt.Errorf("memNetwork: Listen called with invalid address %q: %w", address, err)
+	}
+
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	if m.lns == nil {
+		m.lns = make(map[string]*Listener)
+	}
+	port := ap.Port()
+	for {
+		if port == 0 {
+			port = 33000
+		}
+		key := net.JoinHostPort(ap.Addr().String(), fmt.Sprint(port))
+		_, ok := m.lns[key]
+		if ok {
+			if ap.Port() != 0 {
+				return nil, fmt.Errorf("memNetwork: Listen called with duplicate address %q", address)
+			}
+			port++
+			continue
+		}
+		ln := Listen(key)
+		m.lns[key] = ln
+		ln.onClose = func() {
+			m.mu.Lock()
+			delete(m.lns, key)
+			m.mu.Unlock()
+		}
+		return ln, nil
+	}
+}
+
+func (m *Network) NewLocalTCPListener() net.Listener {
+	ln, err := m.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		panic(fmt.Sprintf("memNetwork: failed to create local TCP listener: %v", err))
+	}
+	return ln
+}
+
+func (m *Network) Dial(ctx context.Context, network, address string) (net.Conn, error) {
+	if network != "tcp" && network != "tcp4" && network != "tcp6" {
+		return nil, fmt.Errorf("memNetwork: Dial called with unsupported network %q", network)
+	}
+	m.mu.Lock()
+	ln, ok := m.lns[address]
+	m.mu.Unlock()
+	if !ok {
+		return nil, fmt.Errorf("memNetwork: Dial called on unknown address %q", address)
+	}
+	return ln.Dial(ctx, network, address)
+}