sing-box/common/redir/redir_linux.go
2022-07-15 08:42:02 +08:00

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
}
}