Xray-core/proxy/dokodemo/fakeudp_linux.go

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// +build linux
package dokodemo
import (
"fmt"
"net"
"os"
"strconv"
"syscall"
)
func FakeUDP(addr *net.UDPAddr, mark int) (net.PacketConn, error) {
if addr == nil {
addr = &net.UDPAddr{
IP: []byte{0, 0, 0, 0},
Port: 0,
}
}
localSocketAddress, af, err := udpAddrToSocketAddr(addr)
if err != nil {
return nil, &net.OpError{Op: "fake", Err: fmt.Errorf("build local socket address: %s", err)}
}
fileDescriptor, err := syscall.Socket(af, syscall.SOCK_DGRAM, 0)
if err != nil {
return nil, &net.OpError{Op: "fake", Err: fmt.Errorf("socket open: %s", err)}
}
if mark != 0 {
if err = syscall.SetsockoptInt(fileDescriptor, syscall.SOL_SOCKET, syscall.SO_MARK, mark); err != nil {
syscall.Close(fileDescriptor)
return nil, &net.OpError{Op: "fake", Err: fmt.Errorf("set socket option: SO_MARK: %s", err)}
}
}
if err = syscall.SetsockoptInt(fileDescriptor, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1); err != nil {
syscall.Close(fileDescriptor)
return nil, &net.OpError{Op: "fake", Err: fmt.Errorf("set socket option: SO_REUSEADDR: %s", err)}
}
if err = syscall.SetsockoptInt(fileDescriptor, syscall.SOL_IP, syscall.IP_TRANSPARENT, 1); err != nil {
syscall.Close(fileDescriptor)
return nil, &net.OpError{Op: "fake", Err: fmt.Errorf("set socket option: IP_TRANSPARENT: %s", err)}
}
if err = syscall.Bind(fileDescriptor, localSocketAddress); err != nil {
syscall.Close(fileDescriptor)
return nil, &net.OpError{Op: "fake", Err: fmt.Errorf("socket bind: %s", err)}
}
fdFile := os.NewFile(uintptr(fileDescriptor), fmt.Sprintf("net-udp-fake-%s", addr.String()))
defer fdFile.Close()
packetConn, err := net.FilePacketConn(fdFile)
if err != nil {
syscall.Close(fileDescriptor)
return nil, &net.OpError{Op: "fake", Err: fmt.Errorf("convert file descriptor to connection: %s", err)}
}
return packetConn, nil
}
func udpAddrToSocketAddr(addr *net.UDPAddr) (syscall.Sockaddr, int, error) {
switch {
case addr.IP.To4() != nil:
ip := [4]byte{}
copy(ip[:], addr.IP.To4())
return &syscall.SockaddrInet4{Addr: ip, Port: addr.Port}, syscall.AF_INET, nil
default:
ip := [16]byte{}
copy(ip[:], addr.IP.To16())
zoneID, err := strconv.ParseUint(addr.Zone, 10, 32)
if err != nil {
return nil, 0, err
}
return &syscall.SockaddrInet6{Addr: ip, Port: addr.Port, ZoneId: uint32(zoneID)}, syscall.AF_INET6, nil
}
}