darwin: stun: support macos with wireguard-go version

go.mod

@@ -1,10 +1,11 @@
 module github.com/tjjh89017/stunmesh-go
 
-go 1.22
+go 1.22.0
 
 require (
 	github.com/cloudflare/cloudflare-go v0.114.0
 	github.com/google/wire v0.6.0
+	github.com/packetcap/go-pcap v0.0.0-20250128134747-e4098f8faef2
 	github.com/pion/stun v0.6.1
 	github.com/rs/zerolog v1.33.0
 	github.com/spf13/viper v1.19.0
@@ -19,6 +20,7 @@ require (
 	github.com/goccy/go-json v0.10.4 // indirect
 	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/go-querystring v1.1.0 // indirect
+	github.com/gopacket/gopacket v1.3.1 // indirect
 	github.com/hashicorp/hcl v1.0.0 // indirect
 	github.com/josharian/native v1.1.0 // indirect
 	github.com/magiconair/properties v1.8.7 // indirect
@@ -34,6 +36,7 @@ require (
 	github.com/pion/transport/v2 v2.2.1 // indirect
 	github.com/sagikazarmark/locafero v0.4.0 // indirect
 	github.com/sagikazarmark/slog-shim v0.1.0 // indirect
+	github.com/sirupsen/logrus v1.9.3 // indirect
 	github.com/sourcegraph/conc v0.3.0 // indirect
 	github.com/spf13/afero v1.11.0 // indirect
 	github.com/spf13/cast v1.6.0 // indirect

go.sum

@@ -21,6 +21,8 @@ github.com/google/go-querystring v1.1.0/go.mod h1:Kcdr2DB4koayq7X8pmAG4sNG59So17
 github.com/google/subcommands v1.2.0/go.mod h1:ZjhPrFU+Olkh9WazFPsl27BQ4UPiG37m3yTrtFlrHVk=
 github.com/google/wire v0.6.0 h1:HBkoIh4BdSxoyo9PveV8giw7ZsaBOvzWKfcg/6MrVwI=
 github.com/google/wire v0.6.0/go.mod h1:F4QhpQ9EDIdJ1Mbop/NZBRB+5yrR6qg3BnctaoUk6NA=
+github.com/gopacket/gopacket v1.3.1 h1:ZppWyLrOJNZPe5XkdjLbtuTkfQoxQ0xyMJzQCqtqaPU=
+github.com/gopacket/gopacket v1.3.1/go.mod h1:3I13qcqSpB2R9fFQg866OOgzylYkZxLTmkvcXhvf6qg=
 github.com/hashicorp/hcl v1.0.0 h1:0Anlzjpi4vEasTeNFn2mLJgTSwt0+6sfsiTG8qcWGx4=
 github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
 github.com/josharian/native v1.1.0 h1:uuaP0hAbW7Y4l0ZRQ6C9zfb7Mg1mbFKry/xzDAfmtLA=
@@ -47,6 +49,8 @@ github.com/mikioh/ipaddr v0.0.0-20190404000644-d465c8ab6721 h1:RlZweED6sbSArvlE9
 github.com/mikioh/ipaddr v0.0.0-20190404000644-d465c8ab6721/go.mod h1:Ickgr2WtCLZ2MDGd4Gr0geeCH5HybhRJbonOgQpvSxc=
 github.com/mitchellh/mapstructure v1.5.0 h1:jeMsZIYE/09sWLaz43PL7Gy6RuMjD2eJVyuac5Z2hdY=
 github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
+github.com/packetcap/go-pcap v0.0.0-20250128134747-e4098f8faef2 h1:yESodjSSmfhuIdhW/wh7l0r6hWV9DMAyTZROxWPND10=
+github.com/packetcap/go-pcap v0.0.0-20250128134747-e4098f8faef2/go.mod h1:zIAoVKeWP0mz4zXY50UYQt6NLg2uwKRswMDcGEqOms4=
 github.com/pelletier/go-toml/v2 v2.2.2 h1:aYUidT7k73Pcl9nb2gScu7NSrKCSHIDE89b3+6Wq+LM=
 github.com/pelletier/go-toml/v2 v2.2.2/go.mod h1:1t835xjRzz80PqgE6HHgN2JOsmgYu/h4qDAS4n929Rs=
 github.com/pion/dtls/v2 v2.2.7 h1:cSUBsETxepsCSFSxC3mc/aDo14qQLMSL+O6IjG28yV8=
@@ -70,6 +74,8 @@ github.com/sagikazarmark/locafero v0.4.0 h1:HApY1R9zGo4DBgr7dqsTH/JJxLTTsOt7u6ke
 github.com/sagikazarmark/locafero v0.4.0/go.mod h1:Pe1W6UlPYUk/+wc/6KFhbORCfqzgYEpgQ3O5fPuL3H4=
 github.com/sagikazarmark/slog-shim v0.1.0 h1:diDBnUNK9N/354PgrxMywXnAwEr1QZcOr6gto+ugjYE=
 github.com/sagikazarmark/slog-shim v0.1.0/go.mod h1:SrcSrq8aKtyuqEI1uvTDTK1arOWRIczQRv+GVI1AkeQ=
+github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
+github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
 github.com/sourcegraph/conc v0.3.0 h1:OQTbbt6P72L20UqAkXXuLOj79LfEanQ+YQFNpLA9ySo=
 github.com/sourcegraph/conc v0.3.0/go.mod h1:Sdozi7LEKbFPqYX2/J+iBAM6HpqSLTASQIKqDmF7Mt0=
 github.com/spf13/afero v1.11.0 h1:WJQKhtpdm3v2IzqG8VMqrr6Rf3UYpEF239Jy9wNepM8=
@@ -85,6 +91,7 @@ github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSS
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/8L+MA=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.3/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
@@ -135,6 +142,7 @@ golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

internal/stun/stun_darwin.go

@@ -1,23 +1,225 @@
 // build +darwin
 package stun
 
-import "context"
+import (
+	"context"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"net"
+	"sync"
+	"syscall"
+	"time"
+
+	pcap "github.com/packetcap/go-pcap"
+	"github.com/pion/stun"
+	"github.com/rs/zerolog"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/route"
+)
+
+const PacketSize = 1600
+
+const (
+	etherOff   = 0
+	ipOff      = etherOff + 14
+	udpOff     = ipOff + 5*4
+	payloadOff = udpOff + 2*4
+)
 
-// NOTE: This is a placeholder implementation for darwin.
 type Stun struct {
+	port       uint16
+	conn       *ipv4.PacketConn
+	handle     *pcap.Handle
+	once       sync.Once
+	packetChan chan *stun.Message
 }
 
 func New(ctx context.Context, port uint16) (*Stun, error) {
-	return &Stun{}, nil
+
+	// use default route to be the interface to listen stun
+	defaultRouteInterface, err := getDefaultRouteInterface()
+	if err != nil {
+		return nil, err
+	}
+
+	handle, err := pcap.OpenLive(defaultRouteInterface, PacketSize, false, 0, pcap.DefaultSyscalls)
+	if err != nil {
+		return nil, err
+	}
+
+	filter := fmt.Sprintf("udp dst port %d and udp[12:4] == 0x2112A442", port)
+	if err := handle.SetBPFFilter(filter); err != nil {
+		return nil, err
+	}
+
+	c, err := net.ListenPacket("ip4:17", "0.0.0.0")
+	if err != nil {
+		return nil, err
+	}
+
+	conn := ipv4.NewPacketConn(c)
+
+	return &Stun{
+		port:       port,
+		conn:       conn,
+		handle:     handle,
+		packetChan: make(chan *stun.Message),
+	}, nil
 }
 
 func (s *Stun) Stop() error {
-	return nil
+	close(s.packetChan)
+	s.handle.Close()
+	return s.conn.Close()
 }
 
 func (s *Stun) Start(ctx context.Context) {
+	logger := zerolog.Ctx(ctx)
+
+	logger.Info().Msgf("starting to listen stun response")
+	s.once.Do(func() {
+		go func() {
+			for {
+				select {
+				case <-ctx.Done():
+					return
+				case <-time.After(time.Duration(StunTimeout) * time.Second):
+					return
+				default:
+					var (
+						buf []byte
+						err error
+					)
+					buf, _, err = s.handle.ReadPacketData()
+					if err != nil {
+						logger.Debug().Msgf("fail to read packet data")
+						continue
+					}
+					// decode STUN
+					m := &stun.Message{
+						Raw: buf[payloadOff:],
+					}
+					if err := m.Decode(); err != nil {
+						logger.Debug().Msgf("fail to decode stun msg")
+						continue
+					}
+					s.packetChan <- m
+					return
+				}
+			}
+		}()
+	})
 }
 
-func (s *Stun) Connect(ctx context.Context, address string) (_ string, _ int, err error) {
-	return "", 0, nil
+func (s *Stun) Connect(ctx context.Context, stunAddr string) (_ string, _ int, err error) {
+	logger := zerolog.Ctx(ctx)
+
+	logger.Info().Msgf("connecting to STUN server: %s", stunAddr)
+	addr, err := net.ResolveUDPAddr("udp4", stunAddr)
+	if err != nil {
+		return "", 0, err
+	}
+
+	packet, err := createStunBindingPacket(s.port, uint16(addr.Port))
+	if err != nil {
+		return "", 0, err
+	}
+
+	_, err = s.conn.WriteTo(packet, nil, addr)
+	if err != nil {
+		return "", 0, err
+	}
+
+	reply, err := s.Read(ctx)
+	if err != nil {
+		return "", 0, err
+	}
+
+	replyAddr := Parse(ctx, reply)
+
+	return replyAddr.IP.String(), replyAddr.Port, nil
+}
+
+func (s *Stun) Read(ctx context.Context) (*stun.Message, error) {
+	select {
+	case m := <-s.packetChan:
+		return m, nil
+	case <-time.After(time.Duration(StunTimeout) * time.Second):
+		return nil, ErrTimeout
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+}
+
+func createStunBindingPacket(srcPort, dstPort uint16) ([]byte, error) {
+	msg, err := stun.Build(stun.TransactionID, stun.BindingRequest)
+	if err != nil {
+		return nil, err
+	}
+	_ = msg.NewTransactionID()
+
+	packetLength := uint16(BindingPacketHeaderSize + len(msg.Raw))
+	checksum := uint16(0)
+
+	buf := make([]byte, BindingPacketHeaderSize)
+	binary.BigEndian.PutUint16(buf[0:], srcPort)
+	binary.BigEndian.PutUint16(buf[2:], dstPort)
+	binary.BigEndian.PutUint16(buf[4:], packetLength)
+	binary.BigEndian.PutUint16(buf[6:], checksum)
+
+	return append(buf, msg.Raw...), nil
+}
+
+func getDefaultRouteInterface() (string, error) {
+	// Fetch the routing information base (RIB) for routes.
+	rib, err := route.FetchRIB(syscall.AF_INET, route.RIBTypeRoute, 0)
+	if err != nil {
+		fmt.Println("Error fetching RIB:", err)
+		return "", err
+	}
+
+	msgs, err := route.ParseRIB(route.RIBTypeRoute, rib)
+	if err != nil {
+		fmt.Println("Error parsing RIB:", err)
+		return "", err
+	}
+
+	var dstIP string
+	var netmask string
+	var ifaceName string
+
+	for _, msg := range msgs {
+		switch m := msg.(type) {
+		case *route.RouteMessage:
+			// Extract destination address.
+			if len(m.Addrs) > syscall.RTAX_NETMASK {
+				switch addr := m.Addrs[syscall.RTAX_DST].(type) {
+				case *route.Inet4Addr:
+					dstIP = net.IPv4(addr.IP[0], addr.IP[1], addr.IP[2], addr.IP[3]).String()
+				}
+				switch addr := m.Addrs[syscall.RTAX_NETMASK].(type) {
+				case *route.Inet4Addr:
+					netmask = net.IPv4Mask(addr.IP[0], addr.IP[1], addr.IP[2], addr.IP[3]).String()
+				}
+			}
+
+			// Extract interface index and name using the Index field.
+			ifaceIndex := m.Index
+			if ifaceIndex != 0 {
+				iface, err := net.InterfaceByIndex(ifaceIndex)
+				if err == nil {
+					ifaceName = iface.Name
+				} else {
+					ifaceName = fmt.Sprintf("if%d", ifaceIndex)
+				}
+			}
+
+			if dstIP == "0.0.0.0" && netmask == "00000000" {
+				return ifaceName, nil
+			}
+		}
+	}
+
+	return "", errors.New("No default route found")
 }