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server.go
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server.go
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//go:build linux
// +build linux
package tproxy
import (
"context"
"io"
"net"
"sync"
"time"
"github.com/faireal/trojan-go/common"
"github.com/faireal/trojan-go/config"
"github.com/faireal/trojan-go/log"
"github.com/faireal/trojan-go/tunnel"
)
const MaxPacketSize = 1024 * 8
type Server struct {
tcpListener net.Listener
udpListener *net.UDPConn
packetChan chan tunnel.PacketConn
timeout time.Duration
mappingLock sync.RWMutex
mapping map[string]*PacketConn
ctx context.Context
cancel context.CancelFunc
}
func (s *Server) Close() error {
s.cancel()
s.tcpListener.Close()
return s.udpListener.Close()
}
func (s *Server) AcceptConn(tunnel.Tunnel) (tunnel.Conn, error) {
conn, err := s.tcpListener.Accept()
if err != nil {
select {
case <-s.ctx.Done():
default:
log.Fatal(common.NewError("tproxy failed to accept connection").Base(err))
}
return nil, common.NewError("tproxy failed to accept conn")
}
dst, err := getOriginalTCPDest(conn.(*net.TCPConn))
if err != nil {
return nil, common.NewError("tproxy failed to obtain original address of tcp socket").Base(err)
}
address, err := tunnel.NewAddressFromAddr("tcp", dst.String())
common.Must(err)
log.Info("tproxy connection from", conn.RemoteAddr().String(), "metadata", dst.String())
return &Conn{
metadata: &tunnel.Metadata{
Address: address,
},
Conn: conn,
}, nil
}
func (s *Server) packetDispatchLoop() {
type tproxyPacketInfo struct {
src *net.UDPAddr
dst *net.UDPAddr
payload []byte
}
packetQueue := make(chan *tproxyPacketInfo, 1024)
go func() {
for {
buf := make([]byte, MaxPacketSize)
n, src, dst, err := ReadFromUDP(s.udpListener, buf)
if err != nil {
select {
case <-s.ctx.Done():
default:
log.Fatal(common.NewError("tproxy failed to read from udp socket").Base(err))
}
s.Close()
return
}
log.Debug("udp packet from", src, "metadata", dst, "size", n)
packetQueue <- &tproxyPacketInfo{
src: src,
dst: dst,
payload: buf[:n],
}
}
}()
for {
var info *tproxyPacketInfo
select {
case info = <-packetQueue:
case <-s.ctx.Done():
log.Debug("exiting")
return
}
s.mappingLock.RLock()
conn, found := s.mapping[info.src.String()]
s.mappingLock.RUnlock()
if !found {
ctx, cancel := context.WithCancel(s.ctx)
conn = &PacketConn{
input: make(chan *packetInfo, 128),
output: make(chan *packetInfo, 128),
PacketConn: s.udpListener,
ctx: ctx,
cancel: cancel,
src: info.src,
}
s.mappingLock.Lock()
s.mapping[info.src.String()] = conn
s.mappingLock.Unlock()
log.Info("new tproxy udp session from", info.src.String(), "metadata", info.dst.String())
s.packetChan <- conn
go func(conn *PacketConn) {
defer conn.Close()
log.Debug("udp packet daemon for", conn.src.String())
for {
select {
case info := <-conn.output:
if info.metadata.AddressType != tunnel.IPv4 &&
info.metadata.AddressType != tunnel.IPv6 {
log.Error("tproxy invalid response metadata address", info.metadata)
continue
}
back, err := DialUDP(
"udp",
&net.UDPAddr{
IP: info.metadata.IP,
Port: info.metadata.Port,
},
conn.src.(*net.UDPAddr),
)
if err != nil {
log.Error(common.NewError("failed to dial tproxy udp").Base(err))
return
}
n, err := back.Write(info.payload)
if err != nil {
log.Error(common.NewError("tproxy udp write error").Base(err))
return
}
log.Debug("recv packet, send back to", conn.src, "payload", len(info.payload), "sent", n)
back.Close()
case <-s.ctx.Done():
log.Debug("exiting")
return
case <-time.After(s.timeout):
s.mappingLock.Lock()
delete(s.mapping, conn.src.String())
s.mappingLock.Unlock()
log.Debug("packet session ", conn.src.String(), "timeout")
return
}
}
}(conn)
}
newInfo := &packetInfo{
metadata: &tunnel.Metadata{
Address: tunnel.NewAddressFromHostPort("udp", info.dst.IP.String(), info.dst.Port),
},
payload: info.payload,
}
select {
case conn.input <- newInfo:
log.Debug("tproxy packet sent with metadata", newInfo.metadata, "size", len(info.payload))
default:
// if we got too many packets, simply drop it
log.Warn("tproxy udp relay queue full!")
}
}
}
func (s *Server) AcceptPacket(tunnel.Tunnel) (tunnel.PacketConn, error) {
select {
case conn := <-s.packetChan:
log.Info("tproxy packet conn accepted")
return conn, nil
case <-s.ctx.Done():
return nil, io.EOF
}
}
func NewServer(ctx context.Context, _ tunnel.Server) (*Server, error) {
cfg := config.FromContext(ctx, Name).(*Config)
ctx, cancel := context.WithCancel(ctx)
listenAddr := tunnel.NewAddressFromHostPort("tcp", cfg.LocalHost, cfg.LocalPort)
ip, err := listenAddr.ResolveIP()
if err != nil {
cancel()
return nil, common.NewError("invalid tproxy local address").Base(err)
}
tcpListener, err := ListenTCP("tcp", &net.TCPAddr{
IP: ip,
Port: cfg.LocalPort,
})
if err != nil {
cancel()
return nil, common.NewError("tproxy failed to listen tcp").Base(err)
}
udpListener, err := ListenUDP("udp", &net.UDPAddr{
IP: ip,
Port: cfg.LocalPort,
})
if err != nil {
cancel()
return nil, common.NewError("tproxy failed to listen udp").Base(err)
}
server := &Server{
tcpListener: tcpListener,
udpListener: udpListener,
ctx: ctx,
cancel: cancel,
timeout: time.Duration(cfg.UDPTimeout) * time.Second,
mapping: make(map[string]*PacketConn),
packetChan: make(chan tunnel.PacketConn, 32),
}
go server.packetDispatchLoop()
log.Info("tproxy server listening on", tcpListener.Addr(), "(tcp)", udpListener.LocalAddr(), "(udp)")
log.Debug("tproxy server created")
return server, nil
}