sing-box/inbound/tproxy.go

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package inbound
import (
"context"
"net"
"net/netip"
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"syscall"
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"github.com/sagernet/sing-box/adapter"
"github.com/sagernet/sing-box/common/redir"
C "github.com/sagernet/sing-box/constant"
"github.com/sagernet/sing-box/log"
"github.com/sagernet/sing-box/option"
"github.com/sagernet/sing/common"
"github.com/sagernet/sing/common/buf"
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"github.com/sagernet/sing/common/control"
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E "github.com/sagernet/sing/common/exceptions"
M "github.com/sagernet/sing/common/metadata"
N "github.com/sagernet/sing/common/network"
"github.com/sagernet/sing/common/udpnat"
)
type TProxy struct {
myInboundAdapter
udpNat *udpnat.Service[netip.AddrPort]
}
func NewTProxy(ctx context.Context, router adapter.Router, logger log.ContextLogger, tag string, options option.TProxyInboundOptions) *TProxy {
tproxy := &TProxy{
myInboundAdapter: myInboundAdapter{
protocol: C.TypeTProxy,
network: options.Network.Build(),
ctx: ctx,
router: router,
logger: logger,
tag: tag,
listenOptions: options.ListenOptions,
},
}
var udpTimeout int64
if options.UDPTimeout != 0 {
udpTimeout = options.UDPTimeout
} else {
udpTimeout = int64(C.UDPTimeout.Seconds())
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}
tproxy.connHandler = tproxy
tproxy.oobPacketHandler = tproxy
tproxy.udpNat = udpnat.New[netip.AddrPort](udpTimeout, tproxy.upstreamContextHandler())
tproxy.packetUpstream = tproxy.udpNat
return tproxy
}
func (t *TProxy) Start() error {
err := t.myInboundAdapter.Start()
if err != nil {
return err
}
if t.tcpListener != nil {
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err = control.Conn(common.MustCast[syscall.Conn](t.tcpListener), func(fd uintptr) error {
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return redir.TProxy(fd, M.SocksaddrFromNet(t.tcpListener.Addr()).Addr.Is6())
})
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if err != nil {
return E.Cause(err, "configure tproxy TCP listener")
}
}
if t.udpConn != nil {
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err = control.Conn(t.udpConn, func(fd uintptr) error {
return redir.TProxy(fd, M.SocksaddrFromNet(t.udpConn.LocalAddr()).Addr.Is6())
})
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if err != nil {
return E.Cause(err, "configure tproxy UDP listener")
}
}
return nil
}
func (t *TProxy) NewConnection(ctx context.Context, conn net.Conn, metadata adapter.InboundContext) error {
metadata.Destination = M.SocksaddrFromNet(conn.LocalAddr())
return t.newConnection(ctx, conn, metadata)
}
func (t *TProxy) NewPacket(ctx context.Context, conn N.PacketConn, buffer *buf.Buffer, oob []byte, metadata adapter.InboundContext) error {
destination, err := redir.GetOriginalDestinationFromOOB(oob)
if err != nil {
return E.Cause(err, "get tproxy destination")
}
metadata.Destination = M.SocksaddrFromNetIP(destination)
t.udpNat.NewContextPacket(ctx, metadata.Source.AddrPort(), buffer, adapter.UpstreamMetadata(metadata), func(natConn N.PacketConn) (context.Context, N.PacketWriter) {
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return adapter.WithContext(log.ContextWithNewID(ctx), &metadata), &tproxyPacketWriter{source: natConn}
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})
return nil
}
type tproxyPacketWriter struct {
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source N.PacketConn
destination M.Socksaddr
conn *net.UDPConn
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}
func (w *tproxyPacketWriter) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
defer buffer.Release()
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var udpConn *net.UDPConn
if w.destination == destination {
if w.conn != nil {
udpConn = w.conn
}
}
if udpConn == nil {
var err error
udpConn, err = redir.DialUDP(destination.UDPAddr(), M.SocksaddrFromNet(w.source.LocalAddr()).UDPAddr())
if err != nil {
return E.Cause(err, "tproxy udp write back")
}
if w.destination == destination {
w.conn = udpConn
} else {
defer udpConn.Close()
}
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}
return common.Error(udpConn.Write(buffer.Bytes()))
}
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func (w *tproxyPacketWriter) Close() error {
return common.Close(common.PtrOrNil(w.conn))
}