mirror of
https://github.com/SagerNet/sing.git
synced 2025-04-04 20:37:40 +03:00
58 lines
1.6 KiB
Go
58 lines
1.6 KiB
Go
package control
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import (
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"encoding/binary"
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"net"
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"net/netip"
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"syscall"
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"unsafe"
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M "github.com/sagernet/sing/common/metadata"
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"golang.org/x/sys/unix"
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)
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const (
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PF_OUT = 0x2
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DIOCNATLOOK = 0xc0544417
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)
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func GetOriginalDestination(conn net.Conn) (netip.AddrPort, error) {
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pfFd, err := syscall.Open("/dev/pf", 0, syscall.O_RDONLY)
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if err != nil {
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return netip.AddrPort{}, err
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}
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defer syscall.Close(pfFd)
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nl := struct {
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saddr, daddr, rsaddr, rdaddr [16]byte
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sxport, dxport, rsxport, rdxport [4]byte
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af, proto, protoVariant, direction uint8
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}{
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af: syscall.AF_INET,
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proto: syscall.IPPROTO_TCP,
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direction: PF_OUT,
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}
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localAddr := M.SocksaddrFromNet(conn.LocalAddr()).Unwrap()
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removeAddr := M.SocksaddrFromNet(conn.RemoteAddr()).Unwrap()
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if localAddr.IsIPv4() {
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copy(nl.saddr[:net.IPv4len], removeAddr.Addr.AsSlice())
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copy(nl.daddr[:net.IPv4len], localAddr.Addr.AsSlice())
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nl.af = syscall.AF_INET
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} else {
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copy(nl.saddr[:], removeAddr.Addr.AsSlice())
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copy(nl.daddr[:], localAddr.Addr.AsSlice())
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nl.af = syscall.AF_INET6
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}
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binary.BigEndian.PutUint16(nl.sxport[:], removeAddr.Port)
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binary.BigEndian.PutUint16(nl.dxport[:], localAddr.Port)
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if _, _, errno := unix.Syscall(syscall.SYS_IOCTL, uintptr(pfFd), DIOCNATLOOK, uintptr(unsafe.Pointer(&nl))); errno != 0 {
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return netip.AddrPort{}, errno
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}
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var address netip.Addr
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if nl.af == unix.AF_INET {
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address = M.AddrFromIP(nl.rdaddr[:net.IPv4len])
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} else {
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address = netip.AddrFrom16(nl.rdaddr)
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}
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return netip.AddrPortFrom(address, binary.BigEndian.Uint16(nl.rdxport[:])), nil
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}
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