stun, netcheck: move under net

net/stun/stuntest/stuntest.go

@@ -0,0 +1,129 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package stuntest provides a STUN test server.
+package stuntest
+
+import (
+	"fmt"
+	"net"
+	"strconv"
+	"strings"
+	"sync"
+	"testing"
+
+	"inet.af/netaddr"
+	"tailscale.com/net/stun"
+	"tailscale.com/tailcfg"
+)
+
+type stunStats struct {
+	mu       sync.Mutex
+	readIPv4 int
+	readIPv6 int
+}
+
+func Serve(t *testing.T) (addr *net.UDPAddr, cleanupFn func()) {
+	t.Helper()
+
+	// TODO(crawshaw): use stats to test re-STUN logic
+	var stats stunStats
+
+	pc, err := net.ListenPacket("udp4", ":0")
+	if err != nil {
+		t.Fatalf("failed to open STUN listener: %v", err)
+	}
+	addr = &net.UDPAddr{
+		IP:   net.ParseIP("127.0.0.1"),
+		Port: pc.LocalAddr().(*net.UDPAddr).Port,
+	}
+	doneCh := make(chan struct{})
+	go runSTUN(t, pc, &stats, doneCh)
+	return addr, func() {
+		pc.Close()
+		<-doneCh
+	}
+}
+
+func runSTUN(t *testing.T, pc net.PacketConn, stats *stunStats, done chan<- struct{}) {
+	defer close(done)
+
+	var buf [64 << 10]byte
+	for {
+		n, addr, err := pc.ReadFrom(buf[:])
+		if err != nil {
+			if strings.Contains(err.Error(), "closed network connection") {
+				t.Logf("STUN server shutdown")
+				return
+			}
+			continue
+		}
+		ua := addr.(*net.UDPAddr)
+		pkt := buf[:n]
+		if !stun.Is(pkt) {
+			continue
+		}
+		txid, err := stun.ParseBindingRequest(pkt)
+		if err != nil {
+			continue
+		}
+
+		stats.mu.Lock()
+		if ua.IP.To4() != nil {
+			stats.readIPv4++
+		} else {
+			stats.readIPv6++
+		}
+		stats.mu.Unlock()
+
+		res := stun.Response(txid, ua.IP, uint16(ua.Port))
+		if _, err := pc.WriteTo(res, addr); err != nil {
+			t.Logf("STUN server write failed: %v", err)
+		}
+	}
+}
+
+func DERPMapOf(stun ...string) *tailcfg.DERPMap {
+	m := &tailcfg.DERPMap{
+		Regions: map[int]*tailcfg.DERPRegion{},
+	}
+	for i, hostPortStr := range stun {
+		regionID := i + 1
+		host, portStr, err := net.SplitHostPort(hostPortStr)
+		if err != nil {
+			panic(fmt.Sprintf("bogus STUN hostport: %q", hostPortStr))
+		}
+		port, err := strconv.Atoi(portStr)
+		if err != nil {
+			panic(fmt.Sprintf("bogus port %q in %q", portStr, hostPortStr))
+		}
+		var ipv4, ipv6 string
+		ip, err := netaddr.ParseIP(host)
+		if err != nil {
+			panic(fmt.Sprintf("bogus non-IP STUN host %q in %q", host, hostPortStr))
+		}
+		if ip.Is4() {
+			ipv4 = host
+			ipv6 = "none"
+		}
+		if ip.Is6() {
+			ipv6 = host
+			ipv4 = "none"
+		}
+		node := &tailcfg.DERPNode{
+			Name:     fmt.Sprint(regionID) + "a",
+			RegionID: regionID,
+			HostName: fmt.Sprintf("d%d.invalid", regionID),
+			IPv4:     ipv4,
+			IPv6:     ipv6,
+			STUNPort: port,
+			STUNOnly: true,
+		}
+		m.Regions[regionID] = &tailcfg.DERPRegion{
+			RegionID: regionID,
+			Nodes:    []*tailcfg.DERPNode{node},
+		}
+	}
+	return m
+}