package redir import ( "net" "syscall" "unsafe" "github.com/Dreamacro/clash/transport/socks5" ) func parserPacket(c net.Conn) (socks5.Addr, error) { const ( PfInout = 0 PfIn = 1 PfOut = 2 IOCOut = 0x40000000 IOCIn = 0x80000000 IOCInOut = IOCIn | IOCOut IOCPARMMask = 0x1FFF LEN = 4*16 + 4*4 + 4*1 // #define _IOC(inout,group,num,len) (inout | ((len & IOCPARMMask) << 16) | ((group) << 8) | (num)) // #define _IOWR(g,n,t) _IOC(IOCInOut, (g), (n), sizeof(t)) // #define DIOCNATLOOK _IOWR('D', 23, struct pfioc_natlook) DIOCNATLOOK = IOCInOut | ((LEN & IOCPARMMask) << 16) | ('D' << 8) | 23 ) fd, err := syscall.Open("/dev/pf", 0, syscall.O_RDONLY) if err != nil { return nil, err } defer syscall.Close(fd) nl := struct { // struct pfioc_natlook saddr, daddr, rsaddr, rdaddr [16]byte sxport, dxport, rsxport, rdxport [4]byte af, proto, protoVariant, direction uint8 }{ af: syscall.AF_INET, proto: syscall.IPPROTO_TCP, direction: PfOut, } saddr := c.RemoteAddr().(*net.TCPAddr) daddr := c.LocalAddr().(*net.TCPAddr) copy(nl.saddr[:], saddr.IP) copy(nl.daddr[:], daddr.IP) nl.sxport[0], nl.sxport[1] = byte(saddr.Port>>8), byte(saddr.Port) nl.dxport[0], nl.dxport[1] = byte(daddr.Port>>8), byte(daddr.Port) if _, _, errno := syscall.Syscall(syscall.SYS_IOCTL, uintptr(fd), DIOCNATLOOK, uintptr(unsafe.Pointer(&nl))); errno != 0 { return nil, errno } addr := make([]byte, 1+net.IPv4len+2) addr[0] = socks5.AtypIPv4 copy(addr[1:1+net.IPv4len], nl.rdaddr[:4]) copy(addr[1+net.IPv4len:], nl.rdxport[:2]) return addr, nil }