XICMP finalmask: Refine Linux sever (#6272)

Fixes https://github.com/XTLS/Xray-core/pull/6168
This commit is contained in:
LjhAUMEM
2026-06-09 17:14:54 +08:00
committed by GitHub
parent a0e9347f1b
commit 6189d2bfd5
2 changed files with 366 additions and 0 deletions
@@ -1,3 +1,5 @@
//go:build !linux
package xicmp
import (
@@ -0,0 +1,364 @@
//go:build linux
package xicmp
import (
"context"
goerrors "errors"
"io"
"net"
"net/netip"
"sync"
"time"
"github.com/xtls/xray-core/common"
"github.com/xtls/xray-core/common/errors"
"github.com/xtls/xray-core/transport/internet/finalmask"
"golang.org/x/net/icmp"
"golang.org/x/net/ipv4"
"golang.org/x/net/ipv6"
)
func clientIDToAddr(clientID [8]byte) *net.UDPAddr {
ip := make(net.IP, 16)
ip[0] = 0xfd
ip[1] = 0x00
copy(ip[8:], clientID[:])
return &net.UDPAddr{IP: ip}
}
type record struct {
id int
seq int
addr net.Addr
dst net.IP
last time.Time
}
type xicmpConnServer struct {
conn net.PacketConn
icmp4 *icmp.PacketConn
icmp6 *icmp.PacketConn
ipv4PC *ipv4.PacketConn
ipv6PC *ipv6.PacketConn
ips map[netip.Addr]struct{}
rec map[string]record
readCh chan packet
closedCh chan struct{}
mu sync.Mutex
}
func NewConnServer(c *Config, raw net.PacketConn) (net.PacketConn, error) {
icmp4, err := icmp.ListenPacket("ip4:icmp", "0.0.0.0")
if err != nil {
return nil, err
}
icmp6, err := icmp.ListenPacket("ip6:ipv6-icmp", "::")
if err != nil {
return nil, err
}
ips := make(map[netip.Addr]struct{})
for _, ip := range c.IPs {
ips[netip.MustParseAddr(ip)] = struct{}{}
}
conn := &xicmpConnServer{
conn: raw,
icmp4: icmp4,
icmp6: icmp6,
ipv4PC: icmp4.IPv4PacketConn(),
ipv6PC: icmp6.IPv6PacketConn(),
ips: ips,
rec: make(map[string]record),
readCh: make(chan packet),
closedCh: make(chan struct{}),
}
common.Must(conn.ipv4PC.SetControlMessage(ipv4.FlagDst, true))
common.Must(conn.ipv6PC.SetControlMessage(ipv6.FlagDst, true))
go conn.clean()
go conn.recv4()
go conn.recv6()
return conn, nil
}
func (c *xicmpConnServer) closed() bool {
select {
case <-c.closedCh:
return true
default:
return false
}
}
func (c *xicmpConnServer) clean() {
ticker := time.NewTicker(time.Minute / 2)
defer ticker.Stop()
for {
select {
case <-ticker.C:
now := time.Now()
c.mu.Lock()
for key, r := range c.rec {
if now.Sub(r.last) > time.Minute {
delete(c.rec, key)
}
}
c.mu.Unlock()
case <-c.closedCh:
return
}
}
}
func (c *xicmpConnServer) recv4() {
var b [finalmask.UDPSize]byte
for {
if c.closed() {
return
}
n, cm, addr, err := c.ipv4PC.ReadFrom(b[:])
if err != nil {
var netErr net.Error
if goerrors.As(err, &netErr) && netErr.Timeout() {
select {
case c.readCh <- packet{
err: err,
}:
case <-c.closedCh:
return
}
}
continue
}
msg, err := icmp.ParseMessage(1, b[:n])
if err != nil {
continue
}
if msg.Type != ipv4.ICMPTypeEcho {
continue
}
echo, ok := msg.Body.(*icmp.Echo)
if !ok {
continue
}
if len(echo.Data) <= 8 {
continue
}
if len(c.ips) > 0 {
netipAddr, ok := netip.AddrFromSlice(addr.(*net.IPAddr).IP)
if !ok {
continue
}
if _, ok := c.ips[netipAddr]; !ok {
continue
}
}
cAddr := clientIDToAddr([8]byte(echo.Data[:8]))
c.mu.Lock()
c.rec[cAddr.String()] = record{
id: echo.ID,
seq: echo.Seq,
addr: addr,
dst: cm.Dst,
last: time.Now(),
}
c.mu.Unlock()
p := pool.Get().([]byte)[:len(echo.Data[8:])]
copy(p, echo.Data[8:])
select {
case c.readCh <- packet{
p: p,
addr: cAddr,
}:
case <-c.closedCh:
pool.Put(p)
return
}
}
}
func (c *xicmpConnServer) recv6() {
var b [finalmask.UDPSize]byte
for {
if c.closed() {
return
}
n, cm, addr, err := c.ipv6PC.ReadFrom(b[:])
if err != nil {
var netErr net.Error
if goerrors.As(err, &netErr) && netErr.Timeout() {
select {
case c.readCh <- packet{
err: err,
}:
case <-c.closedCh:
return
}
}
continue
}
msg, err := icmp.ParseMessage(58, b[:n])
if err != nil {
continue
}
if msg.Type != ipv6.ICMPTypeEchoRequest {
continue
}
echo, ok := msg.Body.(*icmp.Echo)
if !ok {
continue
}
if len(echo.Data) <= 8 {
continue
}
if len(c.ips) > 0 {
netipAddr, ok := netip.AddrFromSlice(addr.(*net.IPAddr).IP)
if !ok {
continue
}
if _, ok := c.ips[netipAddr]; !ok {
continue
}
}
cAddr := clientIDToAddr([8]byte(echo.Data[:8]))
c.mu.Lock()
c.rec[cAddr.String()] = record{
id: echo.ID,
seq: echo.Seq,
addr: addr,
dst: cm.Dst,
last: time.Now(),
}
c.mu.Unlock()
p := pool.Get().([]byte)[:len(echo.Data[8:])]
copy(p, echo.Data[8:])
select {
case c.readCh <- packet{
p: p,
addr: cAddr,
}:
case <-c.closedCh:
pool.Put(p)
return
}
}
}
func (c *xicmpConnServer) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
select {
case packet := <-c.readCh:
if packet.p != nil {
n = copy(p, packet.p)
pool.Put(packet.p)
}
return n, packet.addr, packet.err
case <-c.closedCh:
return 0, nil, io.EOF
}
}
func (c *xicmpConnServer) WriteTo(p []byte, addr net.Addr) (n int, err error) {
if len(p)+8 > finalmask.UDPSize {
errors.LogError(context.Background(), "drop packet to ", addr, " with size ", len(p))
return 0, nil
}
c.mu.Lock()
r, ok := c.rec[addr.String()]
if !ok {
errors.LogError(context.Background(), "drop packet to ", addr, " with size ", len(p))
c.mu.Unlock()
return 0, nil
}
r.last = time.Now()
c.rec[addr.String()] = r
c.mu.Unlock()
// errors.LogDebug(context.Background(), "id ", r.id, " seq ", r.seq, " addr ", r.addr)
b := pool.Get().([]byte)[:finalmask.UDPSize]
defer pool.Put(b)
copy(b[8:], p)
if r.addr.(*net.IPAddr).IP.To4() != nil {
b = marshal(b, ipv4.ICMPTypeEchoReply, r.id, r.seq, len(p))
_, err = c.ipv4PC.WriteTo(b, &ipv4.ControlMessage{Src: r.dst}, r.addr)
} else {
b = marshal(b, ipv6.ICMPTypeEchoReply, r.id, r.seq, len(p))
_, err = c.ipv6PC.WriteTo(b, &ipv6.ControlMessage{Src: r.dst}, r.addr)
}
if err != nil {
errors.LogErrorInner(context.Background(), err, "xicmp write")
return 0, err
}
return len(p), nil
}
func (c *xicmpConnServer) Close() error {
c.mu.Lock()
defer c.mu.Unlock()
if c.closed() {
return nil
}
close(c.closedCh)
_ = c.icmp4.Close()
_ = c.icmp6.Close()
_ = c.conn.Close()
return nil
}
func (c *xicmpConnServer) LocalAddr() net.Addr {
return c.conn.LocalAddr()
}
func (c *xicmpConnServer) SetDeadline(t time.Time) error {
_ = c.icmp4.SetDeadline(t)
_ = c.icmp6.SetDeadline(t)
return nil
}
func (c *xicmpConnServer) SetReadDeadline(t time.Time) error {
_ = c.icmp4.SetReadDeadline(t)
_ = c.icmp6.SetReadDeadline(t)
return nil
}
func (c *xicmpConnServer) SetWriteDeadline(t time.Time) error {
_ = c.icmp4.SetWriteDeadline(t)
_ = c.icmp6.SetWriteDeadline(t)
return nil
}