38 lines
969 B
Go
38 lines
969 B
Go
package redir
|
|
|
|
import (
|
|
"net"
|
|
"net/netip"
|
|
"syscall"
|
|
|
|
M "github.com/sagernet/sing/common/metadata"
|
|
)
|
|
|
|
func GetOriginalDestination(conn net.Conn) (destination netip.AddrPort, err error) {
|
|
rawConn, err := conn.(syscall.Conn).SyscallConn()
|
|
if err != nil {
|
|
return
|
|
}
|
|
var rawFd uintptr
|
|
err = rawConn.Control(func(fd uintptr) {
|
|
rawFd = fd
|
|
})
|
|
if err != nil {
|
|
return
|
|
}
|
|
const SO_ORIGINAL_DST = 80
|
|
if conn.RemoteAddr().(*net.TCPAddr).IP.To4() != nil {
|
|
raw, err := syscall.GetsockoptIPv6Mreq(int(rawFd), syscall.IPPROTO_IP, SO_ORIGINAL_DST)
|
|
if err != nil {
|
|
return netip.AddrPort{}, err
|
|
}
|
|
return netip.AddrPortFrom(M.AddrFromIP(raw.Multiaddr[4:8]), uint16(raw.Multiaddr[2])<<8+uint16(raw.Multiaddr[3])), nil
|
|
} else {
|
|
raw, err := syscall.GetsockoptIPv6MTUInfo(int(rawFd), syscall.IPPROTO_IPV6, SO_ORIGINAL_DST)
|
|
if err != nil {
|
|
return netip.AddrPort{}, err
|
|
}
|
|
return netip.AddrPortFrom(M.AddrFromIP(raw.Addr.Addr[:]), raw.Addr.Port), nil
|
|
}
|
|
}
|