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tailscale/net/stun/stuntest/stuntest.go

138 lines
3.1 KiB
Go

// 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 (
"context"
"fmt"
"net"
"net/netip"
"strconv"
"strings"
"sync"
"testing"
"tailscale.com/net/stun"
"tailscale.com/tailcfg"
"tailscale.com/types/nettype"
)
type stunStats struct {
mu sync.Mutex
readIPv4 int
readIPv6 int
}
func Serve(t testing.TB) (addr *net.UDPAddr, cleanupFn func()) {
return ServeWithPacketListener(t, nettype.Std{})
}
func ServeWithPacketListener(t testing.TB, ln nettype.PacketListener) (addr *net.UDPAddr, cleanupFn func()) {
t.Helper()
// TODO(crawshaw): use stats to test re-STUN logic
var stats stunStats
pc, err := ln.ListenPacket(context.Background(), "udp4", ":0")
if err != nil {
t.Fatalf("failed to open STUN listener: %v", err)
}
addr = pc.LocalAddr().(*net.UDPAddr)
if len(addr.IP) == 0 || addr.IP.IsUnspecified() {
addr.IP = net.ParseIP("127.0.0.1")
}
doneCh := make(chan struct{})
go runSTUN(t, pc, &stats, doneCh)
return addr, func() {
pc.Close()
<-doneCh
}
}
func runSTUN(t testing.TB, 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 {
// TODO: when we switch to Go 1.16, replace this with errors.Is(err, net.ErrClosed)
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()
nia, _ := netip.AddrFromSlice(ua.IP)
res := stun.Response(txid, netip.AddrPortFrom(nia, 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 := netip.ParseAddr(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
}