Finalmask: Add XICMP (relies mKCP/QUIC or WireGuard) (#5633)

https://t.me/projectXtls/1473

transport/internet/finalmask/xdns/client.go

@@ -209,7 +209,7 @@ func (c *xdnsConnClient) WriteTo(p []byte, addr net.Addr) (n int, err error) {
 
 	encoded, err := encode(p, c.clientID, c.domain)
 	if err != nil {
-		errors.LogDebug(context.Background(), "xdns encode err", err)
+		errors.LogDebug(context.Background(), "xdns encode err ", err)
 		return 0, errors.New("xdns encode").Base(err)
 	}
 

transport/internet/finalmask/xicmp/client.go

@@ -0,0 +1,348 @@
+package xicmp
+
+import (
+	"context"
+	"io"
+	"net"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/xtls/xray-core/common/crypto"
+	"github.com/xtls/xray-core/common/errors"
+	"golang.org/x/net/icmp"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+const (
+	initPollDelay       = 500 * time.Millisecond
+	maxPollDelay        = 10 * time.Second
+	pollDelayMultiplier = 2.0
+	pollLimit           = 16
+)
+
+type packet struct {
+	p    []byte
+	addr net.Addr
+}
+
+type seqStatus struct {
+	needSeqByte bool
+	seqByte     byte
+	received    bool
+}
+
+type xicmpConnClient struct {
+	conn     net.PacketConn
+	icmpConn *icmp.PacketConn
+
+	typ       icmp.Type
+	id        int
+	seq       int
+	proto     int
+	seqStatus map[int]*seqStatus
+
+	pollChan   chan struct{}
+	readQueue  chan *packet
+	writeQueue chan *packet
+
+	closed bool
+	mutex  sync.Mutex
+}
+
+func NewConnClient(c *Config, raw net.PacketConn, end bool) (net.PacketConn, error) {
+	if !end {
+		return nil, errors.New("xicmp requires being at the outermost level")
+	}
+
+	network := "ip4:icmp"
+	typ := icmp.Type(ipv4.ICMPTypeEcho)
+	proto := 1
+	if strings.Contains(c.Ip, ":") {
+		network = "ip6:ipv6-icmp"
+		typ = ipv6.ICMPTypeEchoRequest
+		proto = 58
+	}
+
+	icmpConn, err := icmp.ListenPacket(network, c.Ip)
+	if err != nil {
+		return nil, errors.New("xicmp listen err").Base(err)
+	}
+
+	if c.Id == 0 {
+		c.Id = int32(crypto.RandBetween(0, 65535))
+	}
+
+	conn := &xicmpConnClient{
+		conn:     raw,
+		icmpConn: icmpConn,
+
+		typ:       typ,
+		id:        int(c.Id),
+		seq:       1,
+		proto:     proto,
+		seqStatus: make(map[int]*seqStatus),
+
+		pollChan:   make(chan struct{}, pollLimit),
+		readQueue:  make(chan *packet, 128),
+		writeQueue: make(chan *packet, 128),
+	}
+
+	go conn.recvLoop()
+	go conn.sendLoop()
+
+	return conn, nil
+}
+
+func (c *xicmpConnClient) encode(p []byte) ([]byte, error) {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	needSeqByte := false
+	var seqByte byte
+	data := p
+	if len(p) > 0 {
+		needSeqByte = true
+		seqByte = p[0]
+	}
+
+	msg := icmp.Message{
+		Type: c.typ,
+		Code: 0,
+		Body: &icmp.Echo{
+			ID:   c.id,
+			Seq:  c.seq,
+			Data: data,
+		},
+	}
+
+	buf, err := msg.Marshal(nil)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(buf) > 8192 {
+		return nil, errors.New("xicmp len(buf) > 8192")
+	}
+
+	c.seqStatus[c.seq] = &seqStatus{
+		needSeqByte: needSeqByte,
+		seqByte:     seqByte,
+		received:    false,
+	}
+
+	c.seq++
+
+	if c.seq == 65536 {
+		c.seq = 1
+	}
+
+	return buf, nil
+}
+
+func (c *xicmpConnClient) recvLoop() {
+	for {
+		if c.closed {
+			break
+		}
+
+		var buf [8192]byte
+
+		n, addr, err := c.icmpConn.ReadFrom(buf[:])
+		if err != nil {
+			continue
+		}
+
+		msg, err := icmp.ParseMessage(c.proto, buf[:n])
+		if err != nil {
+			continue
+		}
+
+		if msg.Type != ipv4.ICMPTypeEchoReply && msg.Type != ipv6.ICMPTypeEchoReply {
+			continue
+		}
+
+		echo, ok := msg.Body.(*icmp.Echo)
+		if !ok {
+			continue
+		}
+
+		seqStatus, ok := c.seqStatus[echo.Seq]
+
+		if !ok {
+			continue
+		}
+
+		if seqStatus.received {
+			continue
+		}
+
+		if seqStatus.needSeqByte {
+			if len(echo.Data) <= 1 {
+				continue
+			}
+			if echo.Data[0] == seqStatus.seqByte {
+				continue
+			}
+			echo.Data = echo.Data[1:]
+		}
+
+		if len(echo.Data) > 0 {
+			seqStatus.received = true
+
+			buf := make([]byte, len(echo.Data))
+			copy(buf, echo.Data)
+			select {
+			case c.readQueue <- &packet{
+				p:    buf,
+				addr: &net.UDPAddr{IP: addr.(*net.IPAddr).IP},
+			}:
+			default:
+			}
+
+			select {
+			case c.pollChan <- struct{}{}:
+			default:
+			}
+		}
+	}
+
+	close(c.pollChan)
+	close(c.readQueue)
+}
+
+func (c *xicmpConnClient) sendLoop() {
+	var addr net.Addr
+
+	pollDelay := initPollDelay
+	pollTimer := time.NewTimer(pollDelay)
+	for {
+		var p *packet
+		pollTimerExpired := false
+
+		select {
+		case p = <-c.writeQueue:
+		default:
+			select {
+			case p = <-c.writeQueue:
+			case <-c.pollChan:
+			case <-pollTimer.C:
+				pollTimerExpired = true
+			}
+		}
+
+		if p != nil {
+			addr = p.addr
+
+			select {
+			case <-c.pollChan:
+			default:
+			}
+		} else if addr != nil {
+			encoded, _ := c.encode(nil)
+			p = &packet{
+				p:    encoded,
+				addr: addr,
+			}
+		}
+
+		if pollTimerExpired {
+			pollDelay = time.Duration(float64(pollDelay) * pollDelayMultiplier)
+			if pollDelay > maxPollDelay {
+				pollDelay = maxPollDelay
+			}
+		} else {
+			if !pollTimer.Stop() {
+				<-pollTimer.C
+			}
+			pollDelay = initPollDelay
+		}
+		pollTimer.Reset(pollDelay)
+
+		if c.closed {
+			return
+		}
+
+		if p != nil {
+			_, err := c.icmpConn.WriteTo(p.p, p.addr)
+			if err != nil {
+				errors.LogDebug(context.Background(), "xicmp writeto err ", err)
+			}
+		}
+	}
+}
+
+func (c *xicmpConnClient) Size() int32 {
+	return 0
+}
+
+func (c *xicmpConnClient) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
+	packet, ok := <-c.readQueue
+	if !ok {
+		return 0, nil, io.EOF
+	}
+	n = copy(p, packet.p)
+	if n != len(packet.p) {
+		return 0, nil, io.ErrShortBuffer
+	}
+	return n, packet.addr, nil
+}
+
+func (c *xicmpConnClient) WriteTo(p []byte, addr net.Addr) (n int, err error) {
+	encoded, err := c.encode(p)
+	if err != nil {
+		return 0, errors.New("xicmp encode").Base(err)
+	}
+
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	if c.closed {
+		return 0, errors.New("xicmp closed")
+	}
+
+	select {
+	case c.writeQueue <- &packet{
+		p:    encoded,
+		addr: &net.IPAddr{IP: addr.(*net.UDPAddr).IP},
+	}:
+		return len(p), nil
+	default:
+		return 0, errors.New("xicmp queue full")
+	}
+}
+
+func (c *xicmpConnClient) Close() error {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	if c.closed {
+		return nil
+	}
+
+	c.closed = true
+	close(c.writeQueue)
+
+	_ = c.icmpConn.Close()
+	return c.conn.Close()
+}
+
+func (c *xicmpConnClient) LocalAddr() net.Addr {
+	return &net.UDPAddr{
+		IP:   c.icmpConn.LocalAddr().(*net.IPAddr).IP,
+		Port: c.id,
+	}
+}
+
+func (c *xicmpConnClient) SetDeadline(t time.Time) error {
+	return c.icmpConn.SetDeadline(t)
+}
+
+func (c *xicmpConnClient) SetReadDeadline(t time.Time) error {
+	return c.icmpConn.SetReadDeadline(t)
+}
+
+func (c *xicmpConnClient) SetWriteDeadline(t time.Time) error {
+	return c.icmpConn.SetWriteDeadline(t)
+}

transport/internet/finalmask/xicmp/config.go

@@ -0,0 +1,16 @@
+package xicmp
+
+import (
+	"net"
+)
+
+func (c *Config) UDP() {
+}
+
+func (c *Config) WrapPacketConnClient(raw net.PacketConn, first bool, leaveSize int32, end bool) (net.PacketConn, error) {
+	return NewConnClient(c, raw, end)
+}
+
+func (c *Config) WrapPacketConnServer(raw net.PacketConn, first bool, leaveSize int32, end bool) (net.PacketConn, error) {
+	return NewConnServer(c, raw, end)
+}

transport/internet/finalmask/xicmp/config.pb.go

@@ -0,0 +1,132 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// versions:
+// 	protoc-gen-go v1.36.10
+// 	protoc        v6.33.1
+// source: transport/internet/finalmask/xicmp/config.proto
+
+package xicmp
+
+import (
+	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
+	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
+	reflect "reflect"
+	sync "sync"
+	unsafe "unsafe"
+)
+
+const (
+	// Verify that this generated code is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(20 - protoimpl.MinVersion)
+	// Verify that runtime/protoimpl is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
+)
+
+type Config struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	Ip            string                 `protobuf:"bytes,1,opt,name=ip,proto3" json:"ip,omitempty"`
+	Id            int32                  `protobuf:"varint,2,opt,name=id,proto3" json:"id,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *Config) Reset() {
+	*x = Config{}
+	mi := &file_transport_internet_finalmask_xicmp_config_proto_msgTypes[0]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *Config) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*Config) ProtoMessage() {}
+
+func (x *Config) ProtoReflect() protoreflect.Message {
+	mi := &file_transport_internet_finalmask_xicmp_config_proto_msgTypes[0]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use Config.ProtoReflect.Descriptor instead.
+func (*Config) Descriptor() ([]byte, []int) {
+	return file_transport_internet_finalmask_xicmp_config_proto_rawDescGZIP(), []int{0}
+}
+
+func (x *Config) GetIp() string {
+	if x != nil {
+		return x.Ip
+	}
+	return ""
+}
+
+func (x *Config) GetId() int32 {
+	if x != nil {
+		return x.Id
+	}
+	return 0
+}
+
+var File_transport_internet_finalmask_xicmp_config_proto protoreflect.FileDescriptor
+
+const file_transport_internet_finalmask_xicmp_config_proto_rawDesc = "" +
+	"\n" +
+	"/transport/internet/finalmask/xicmp/config.proto\x12'xray.transport.internet.finalmask.xicmp\"(\n" +
+	"\x06Config\x12\x0e\n" +
+	"\x02ip\x18\x01 \x01(\tR\x02ip\x12\x0e\n" +
+	"\x02id\x18\x02 \x01(\x05R\x02idB\x97\x01\n" +
+	"+com.xray.transport.internet.finalmask.xicmpP\x01Z<github.com/xtls/xray-core/transport/internet/finalmask/xicmp\xaa\x02'Xray.Transport.Internet.Finalmask.Xicmpb\x06proto3"
+
+var (
+	file_transport_internet_finalmask_xicmp_config_proto_rawDescOnce sync.Once
+	file_transport_internet_finalmask_xicmp_config_proto_rawDescData []byte
+)
+
+func file_transport_internet_finalmask_xicmp_config_proto_rawDescGZIP() []byte {
+	file_transport_internet_finalmask_xicmp_config_proto_rawDescOnce.Do(func() {
+		file_transport_internet_finalmask_xicmp_config_proto_rawDescData = protoimpl.X.CompressGZIP(unsafe.Slice(unsafe.StringData(file_transport_internet_finalmask_xicmp_config_proto_rawDesc), len(file_transport_internet_finalmask_xicmp_config_proto_rawDesc)))
+	})
+	return file_transport_internet_finalmask_xicmp_config_proto_rawDescData
+}
+
+var file_transport_internet_finalmask_xicmp_config_proto_msgTypes = make([]protoimpl.MessageInfo, 1)
+var file_transport_internet_finalmask_xicmp_config_proto_goTypes = []any{
+	(*Config)(nil), // 0: xray.transport.internet.finalmask.xicmp.Config
+}
+var file_transport_internet_finalmask_xicmp_config_proto_depIdxs = []int32{
+	0, // [0:0] is the sub-list for method output_type
+	0, // [0:0] is the sub-list for method input_type
+	0, // [0:0] is the sub-list for extension type_name
+	0, // [0:0] is the sub-list for extension extendee
+	0, // [0:0] is the sub-list for field type_name
+}
+
+func init() { file_transport_internet_finalmask_xicmp_config_proto_init() }
+func file_transport_internet_finalmask_xicmp_config_proto_init() {
+	if File_transport_internet_finalmask_xicmp_config_proto != nil {
+		return
+	}
+	type x struct{}
+	out := protoimpl.TypeBuilder{
+		File: protoimpl.DescBuilder{
+			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
+			RawDescriptor: unsafe.Slice(unsafe.StringData(file_transport_internet_finalmask_xicmp_config_proto_rawDesc), len(file_transport_internet_finalmask_xicmp_config_proto_rawDesc)),
+			NumEnums:      0,
+			NumMessages:   1,
+			NumExtensions: 0,
+			NumServices:   0,
+		},
+		GoTypes:           file_transport_internet_finalmask_xicmp_config_proto_goTypes,
+		DependencyIndexes: file_transport_internet_finalmask_xicmp_config_proto_depIdxs,
+		MessageInfos:      file_transport_internet_finalmask_xicmp_config_proto_msgTypes,
+	}.Build()
+	File_transport_internet_finalmask_xicmp_config_proto = out.File
+	file_transport_internet_finalmask_xicmp_config_proto_goTypes = nil
+	file_transport_internet_finalmask_xicmp_config_proto_depIdxs = nil
+}

transport/internet/finalmask/xicmp/config.proto

@@ -0,0 +1,13 @@
+syntax = "proto3";
+
+package xray.transport.internet.finalmask.xicmp;
+option csharp_namespace = "Xray.Transport.Internet.Finalmask.Xicmp";
+option go_package = "github.com/xtls/xray-core/transport/internet/finalmask/xicmp";
+option java_package = "com.xray.transport.internet.finalmask.xicmp";
+option java_multiple_files = true;
+
+message Config {
+  string ip = 1;
+  int32 id = 2;
+}
+

transport/internet/finalmask/xicmp/server.go

@@ -0,0 +1,377 @@
+package xicmp
+
+import (
+	"context"
+	"io"
+	"net"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/xtls/xray-core/common/crypto"
+	"github.com/xtls/xray-core/common/errors"
+	"golang.org/x/net/icmp"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+const (
+	idleTimeout      = 2 * time.Minute
+	maxResponseDelay = 1 * time.Second
+)
+
+type record struct {
+	id          int
+	seq         int
+	needSeqByte bool
+	seqByte     byte
+	addr        net.Addr
+}
+
+type queue struct {
+	lash  time.Time
+	queue chan []byte
+}
+
+type xicmpConnServer struct {
+	conn     net.PacketConn
+	icmpConn *icmp.PacketConn
+
+	typ    icmp.Type
+	proto  int
+	config *Config
+
+	ch            chan *record
+	readQueue     chan *packet
+	writeQueueMap map[string]*queue
+
+	closed bool
+	mutex  sync.Mutex
+}
+
+func NewConnServer(c *Config, raw net.PacketConn, end bool) (net.PacketConn, error) {
+	if !end {
+		return nil, errors.New("xicmp requires being at the outermost level")
+	}
+
+	network := "ip4:icmp"
+	typ := icmp.Type(ipv4.ICMPTypeEchoReply)
+	proto := 1
+	if strings.Contains(c.Ip, ":") {
+		network = "ip6:ipv6-icmp"
+		typ = ipv6.ICMPTypeEchoReply
+		proto = 58
+	}
+
+	icmpConn, err := icmp.ListenPacket(network, c.Ip)
+	if err != nil {
+		return nil, errors.New("xicmp listen err").Base(err)
+	}
+
+	conn := &xicmpConnServer{
+		conn:     raw,
+		icmpConn: icmpConn,
+
+		typ:    typ,
+		proto:  proto,
+		config: c,
+
+		ch:            make(chan *record, 100),
+		readQueue:     make(chan *packet, 128),
+		writeQueueMap: make(map[string]*queue),
+	}
+
+	go conn.clean()
+	go conn.recvLoop()
+	go conn.sendLoop()
+
+	return conn, nil
+}
+
+func (c *xicmpConnServer) clean() {
+	f := func() bool {
+		c.mutex.Lock()
+		defer c.mutex.Unlock()
+
+		if c.closed {
+			return true
+		}
+
+		now := time.Now()
+
+		for key, q := range c.writeQueueMap {
+			if now.Sub(q.lash) >= idleTimeout {
+				close(q.queue)
+				delete(c.writeQueueMap, key)
+			}
+		}
+
+		return false
+	}
+
+	for {
+		time.Sleep(idleTimeout / 2)
+		if f() {
+			return
+		}
+	}
+}
+
+func (c *xicmpConnServer) ensureQueue(addr net.Addr) *queue {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	if c.closed {
+		return nil
+	}
+
+	q, ok := c.writeQueueMap[addr.String()]
+	if !ok {
+		q = &queue{
+			queue: make(chan []byte, 128),
+		}
+		c.writeQueueMap[addr.String()] = q
+	}
+	q.lash = time.Now()
+
+	return q
+}
+
+func (c *xicmpConnServer) encode(p []byte, id int, seq int, needSeqByte bool, seqByte byte) ([]byte, error) {
+	data := p
+	if needSeqByte {
+		b2 := c.randUntil(seqByte)
+		data = append([]byte{b2}, p...)
+	}
+
+	msg := icmp.Message{
+		Type: c.typ,
+		Code: 0,
+		Body: &icmp.Echo{
+			ID:   id,
+			Seq:  seq,
+			Data: data,
+		},
+	}
+
+	buf, err := msg.Marshal(nil)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(buf) > 8192 {
+		return nil, errors.New("xicmp len(buf) > 8192")
+	}
+
+	return buf, nil
+}
+
+func (c *xicmpConnServer) randUntil(b1 byte) byte {
+	b2 := byte(crypto.RandBetween(0, 255))
+	for {
+		if b2 != b1 {
+			return b2
+		}
+		b2 = byte(crypto.RandBetween(0, 255))
+	}
+}
+
+func (c *xicmpConnServer) recvLoop() {
+	for {
+		if c.closed {
+			break
+		}
+
+		var buf [8192]byte
+
+		n, addr, err := c.icmpConn.ReadFrom(buf[:])
+		if err != nil {
+			continue
+		}
+
+		msg, err := icmp.ParseMessage(c.proto, buf[:n])
+		if err != nil {
+			continue
+		}
+
+		if msg.Type != ipv4.ICMPTypeEcho && msg.Type != ipv6.ICMPTypeEchoRequest {
+			continue
+		}
+
+		echo, ok := msg.Body.(*icmp.Echo)
+		if !ok {
+			continue
+		}
+
+		if c.config.Id != 0 && echo.ID != int(c.config.Id) {
+			continue
+		}
+
+		needSeqByte := false
+		var seqByte byte
+
+		if len(echo.Data) > 0 {
+			needSeqByte = true
+			seqByte = echo.Data[0]
+
+			buf := make([]byte, len(echo.Data))
+			copy(buf, echo.Data)
+			select {
+			case c.readQueue <- &packet{
+				p: buf,
+				addr: &net.UDPAddr{
+					IP:   addr.(*net.IPAddr).IP,
+					Port: echo.ID,
+				},
+			}:
+			default:
+			}
+		}
+
+		select {
+		case c.ch <- &record{
+			id:          echo.ID,
+			seq:         echo.Seq,
+			needSeqByte: needSeqByte,
+			seqByte:     seqByte,
+			addr: &net.UDPAddr{
+				IP:   addr.(*net.IPAddr).IP,
+				Port: echo.ID,
+			},
+		}:
+		default:
+		}
+	}
+
+	close(c.ch)
+	close(c.readQueue)
+}
+
+func (c *xicmpConnServer) sendLoop() {
+	var nextRec *record
+	for {
+		rec := nextRec
+		nextRec = nil
+
+		if rec == nil {
+			var ok bool
+			rec, ok = <-c.ch
+			if !ok {
+				break
+			}
+		}
+
+		queue := c.ensureQueue(rec.addr)
+		if queue == nil {
+			return
+		}
+
+		var p []byte
+
+		timer := time.NewTimer(maxResponseDelay)
+
+		select {
+		case p = <-queue.queue:
+		default:
+			select {
+			case p = <-queue.queue:
+			case <-timer.C:
+			case nextRec = <-c.ch:
+			}
+		}
+
+		timer.Stop()
+
+		if len(p) == 0 {
+			continue
+		}
+
+		buf, err := c.encode(p, rec.id, rec.seq, rec.needSeqByte, rec.seqByte)
+		if err != nil {
+			continue
+		}
+
+		if c.closed {
+			return
+		}
+
+		_, err = c.icmpConn.WriteTo(buf, &net.IPAddr{IP: rec.addr.(*net.UDPAddr).IP})
+		if err != nil {
+			errors.LogDebug(context.Background(), "xicmp writeto err ", err)
+		}
+	}
+}
+
+func (c *xicmpConnServer) Size() int32 {
+	return 0
+}
+
+func (c *xicmpConnServer) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
+	packet, ok := <-c.readQueue
+	if !ok {
+		return 0, nil, io.EOF
+	}
+	n = copy(p, packet.p)
+	if n != len(packet.p) {
+		return 0, nil, io.ErrShortBuffer
+	}
+	return n, packet.addr, nil
+}
+
+func (c *xicmpConnServer) WriteTo(p []byte, addr net.Addr) (n int, err error) {
+	q := c.ensureQueue(addr)
+	if q == nil {
+		return 0, errors.New("xicmp closed")
+	}
+
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	if c.closed {
+		return 0, errors.New("xicmp closed")
+	}
+
+	buf := make([]byte, len(p))
+	copy(buf, p)
+
+	select {
+	case q.queue <- buf:
+		return len(p), nil
+	default:
+		return 0, errors.New("xicmp queue full")
+	}
+}
+
+func (c *xicmpConnServer) Close() error {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	if c.closed {
+		return nil
+	}
+
+	c.closed = true
+	for key, q := range c.writeQueueMap {
+		close(q.queue)
+		delete(c.writeQueueMap, key)
+	}
+
+	_ = c.icmpConn.Close()
+	return c.conn.Close()
+}
+
+func (c *xicmpConnServer) LocalAddr() net.Addr {
+	return &net.UDPAddr{IP: c.icmpConn.LocalAddr().(*net.IPAddr).IP}
+}
+
+func (c *xicmpConnServer) SetDeadline(t time.Time) error {
+	return c.icmpConn.SetDeadline(t)
+}
+
+func (c *xicmpConnServer) SetReadDeadline(t time.Time) error {
+	return c.icmpConn.SetReadDeadline(t)
+}
+
+func (c *xicmpConnServer) SetWriteDeadline(t time.Time) error {
+	return c.icmpConn.SetWriteDeadline(t)
+}

transport/internet/finalmask/xicmp/xicmp_test.go

@@ -0,0 +1,74 @@
+package xicmp_test
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+
+	"golang.org/x/net/icmp"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+func TestICMPEchoMarshal(t *testing.T) {
+	msg := icmp.Message{
+		Type: ipv4.ICMPTypeEcho,
+		Code: 0,
+		Body: &icmp.Echo{
+			ID:   65535,
+			Seq:  65537,
+			Data: nil,
+		},
+	}
+	ICMPTypeEcho, _ := msg.Marshal(nil)
+	fmt.Println("ICMPTypeEcho", len(ICMPTypeEcho), ICMPTypeEcho)
+
+	msg = icmp.Message{
+		Type: ipv4.ICMPTypeEchoReply,
+		Code: 0,
+		Body: &icmp.Echo{
+			ID:   65535,
+			Seq:  65537,
+			Data: nil,
+		},
+	}
+	ICMPTypeEchoReply, _ := msg.Marshal(nil)
+	fmt.Println("ICMPTypeEchoReply", len(ICMPTypeEchoReply), ICMPTypeEchoReply)
+
+	msg = icmp.Message{
+		Type: ipv6.ICMPTypeEchoRequest,
+		Code: 0,
+		Body: &icmp.Echo{
+			ID:   65535,
+			Seq:  65537,
+			Data: nil,
+		},
+	}
+	ICMPTypeEchoRequest, _ := msg.Marshal(nil)
+	fmt.Println("ICMPTypeEchoRequest", len(ICMPTypeEchoRequest), ICMPTypeEchoRequest)
+
+	msg = icmp.Message{
+		Type: ipv6.ICMPTypeEchoReply,
+		Code: 0,
+		Body: &icmp.Echo{
+			ID:   65535,
+			Seq:  65537,
+			Data: nil,
+		},
+	}
+	V6ICMPTypeEchoReply, _ := msg.Marshal(nil)
+	fmt.Println("V6ICMPTypeEchoReply", len(V6ICMPTypeEchoReply), V6ICMPTypeEchoReply)
+
+	if !bytes.Equal(ICMPTypeEcho[0:2], []byte{8, 0}) || !bytes.Equal(ICMPTypeEcho[4:], []byte{255, 255, 0, 1}) {
+		t.Fatalf("ICMPTypeEcho Type/Code or ID/Seq mismatch: %v", ICMPTypeEcho)
+	}
+	if !bytes.Equal(ICMPTypeEchoReply[0:2], []byte{0, 0}) || !bytes.Equal(ICMPTypeEchoReply[4:], []byte{255, 255, 0, 1}) {
+		t.Fatalf("ICMPTypeEchoReply Type/Code or ID/Seq mismatch: %v", ICMPTypeEchoReply)
+	}
+	if !bytes.Equal(ICMPTypeEchoRequest[0:2], []byte{128, 0}) || !bytes.Equal(ICMPTypeEchoRequest[4:], []byte{255, 255, 0, 1}) {
+		t.Fatalf("ICMPTypeEchoRequest Type/Code or ID/Seq mismatch: %v", ICMPTypeEchoRequest)
+	}
+	if !bytes.Equal(V6ICMPTypeEchoReply[0:2], []byte{129, 0}) || !bytes.Equal(V6ICMPTypeEchoReply[4:], []byte{255, 255, 0, 1}) {
+		t.Fatalf("V6ICMPTypeEchoReply Type/Code or ID/Seq mismatch: %v", V6ICMPTypeEchoReply)
+	}
+}