mirror of https://github.com/Dreamacro/clash.git
97 lines
2.0 KiB
Go
97 lines
2.0 KiB
Go
|
// +build linux
|
||
|
|
|
||
|
|
package redir
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
"net"
|
||
|
|
"os"
|
||
|
|
"strconv"
|
||
|
|
"syscall"
|
||
|
|
)
|
||
|
|
|
||
|
|
// 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
|
||
|
|
}
|