mirror of
https://github.com/MetaCubeX/mihomo.git
synced 2024-09-06 09:02:32 +00:00
124 lines
2.8 KiB
Go
124 lines
2.8 KiB
Go
//go:build linux
|
|
|
|
package tproxy
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"errors"
|
|
"fmt"
|
|
"net"
|
|
"os"
|
|
"strconv"
|
|
"syscall"
|
|
)
|
|
|
|
const (
|
|
IPV6_TRANSPARENT = 0x4b
|
|
IPV6_RECVORIGDSTADDR = 0x4a
|
|
)
|
|
|
|
// dialUDP acts like net.DialUDP for transparent proxy.
|
|
// It binds to a non-local address(`lAddr`).
|
|
func dialUDP(network string, lAddr *net.UDPAddr, rAddr *net.UDPAddr) (*net.UDPConn, error) {
|
|
rSockAddr, err := udpAddrToSockAddr(rAddr)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
lSockAddr, err := udpAddrToSockAddr(lAddr)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
fd, err := syscall.Socket(udpAddrFamily(network, lAddr, rAddr), syscall.SOCK_DGRAM, 0)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
if err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1); err != nil {
|
|
syscall.Close(fd)
|
|
return nil, err
|
|
}
|
|
|
|
if err = syscall.SetsockoptInt(fd, syscall.SOL_IP, syscall.IP_TRANSPARENT, 1); err != nil {
|
|
syscall.Close(fd)
|
|
return nil, err
|
|
}
|
|
|
|
if err = syscall.Bind(fd, lSockAddr); err != nil {
|
|
syscall.Close(fd)
|
|
return nil, err
|
|
}
|
|
|
|
if err = syscall.Connect(fd, rSockAddr); err != nil {
|
|
syscall.Close(fd)
|
|
return nil, err
|
|
}
|
|
|
|
fdFile := os.NewFile(uintptr(fd), fmt.Sprintf("net-udp-dial-%s", rAddr.String()))
|
|
defer fdFile.Close()
|
|
|
|
c, err := net.FileConn(fdFile)
|
|
if err != nil {
|
|
syscall.Close(fd)
|
|
return nil, err
|
|
}
|
|
|
|
return c.(*net.UDPConn), nil
|
|
}
|
|
|
|
func udpAddrToSockAddr(addr *net.UDPAddr) (syscall.Sockaddr, error) {
|
|
switch {
|
|
case addr.IP.To4() != nil:
|
|
ip := [4]byte{}
|
|
copy(ip[:], addr.IP.To4())
|
|
|
|
return &syscall.SockaddrInet4{Addr: ip, Port: addr.Port}, nil
|
|
|
|
default:
|
|
ip := [16]byte{}
|
|
copy(ip[:], addr.IP.To16())
|
|
|
|
zoneID, err := strconv.ParseUint(addr.Zone, 10, 32)
|
|
if err != nil {
|
|
zoneID = 0
|
|
}
|
|
|
|
return &syscall.SockaddrInet6{Addr: ip, Port: addr.Port, ZoneId: uint32(zoneID)}, nil
|
|
}
|
|
}
|
|
|
|
func udpAddrFamily(net string, lAddr, rAddr *net.UDPAddr) int {
|
|
switch net[len(net)-1] {
|
|
case '4':
|
|
return syscall.AF_INET
|
|
case '6':
|
|
return syscall.AF_INET6
|
|
}
|
|
|
|
if (lAddr == nil || lAddr.IP.To4() != nil) && (rAddr == nil || lAddr.IP.To4() != nil) {
|
|
return syscall.AF_INET
|
|
}
|
|
return syscall.AF_INET6
|
|
}
|
|
|
|
func getOrigDst(oob []byte, oobn int) (*net.UDPAddr, error) {
|
|
msgs, err := syscall.ParseSocketControlMessage(oob[:oobn])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
for _, msg := range msgs {
|
|
if msg.Header.Level == syscall.SOL_IP && msg.Header.Type == syscall.IP_RECVORIGDSTADDR {
|
|
ip := net.IP(msg.Data[4:8])
|
|
port := binary.BigEndian.Uint16(msg.Data[2:4])
|
|
return &net.UDPAddr{IP: ip, Port: int(port)}, nil
|
|
} else if msg.Header.Level == syscall.SOL_IPV6 && msg.Header.Type == IPV6_RECVORIGDSTADDR {
|
|
ip := net.IP(msg.Data[8:24])
|
|
port := binary.BigEndian.Uint16(msg.Data[2:4])
|
|
return &net.UDPAddr{IP: ip, Port: int(port)}, nil
|
|
}
|
|
}
|
|
|
|
return nil, errors.New("cannot find origDst")
|
|
}
|