133 lines
3.2 KiB
Go
133 lines
3.2 KiB
Go
package redir
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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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"os"
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"strconv"
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"syscall"
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E "github.com/sagernet/sing/common/exceptions"
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F "github.com/sagernet/sing/common/format"
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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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func TProxy(fd uintptr, isIPv6 bool) error {
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err := syscall.SetsockoptInt(int(fd), syscall.SOL_IP, syscall.IP_TRANSPARENT, 1)
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if err != nil {
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return err
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}
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if isIPv6 {
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err = syscall.SetsockoptInt(int(fd), syscall.SOL_IPV6, unix.IPV6_TRANSPARENT, 1)
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}
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return err
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}
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func TProxyUDP(fd uintptr, isIPv6 bool) error {
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err := syscall.SetsockoptInt(int(fd), syscall.SOL_IP, syscall.IP_RECVORIGDSTADDR, 1)
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if err != nil {
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return err
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}
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if isIPv6 {
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err = syscall.SetsockoptInt(int(fd), syscall.SOL_IPV6, unix.IPV6_RECVORIGDSTADDR, 1)
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if err != nil {
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return err
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}
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}
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return nil
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}
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func GetOriginalDestinationFromOOB(oob []byte) (netip.AddrPort, error) {
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controlMessages, err := unix.ParseSocketControlMessage(oob)
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if err != nil {
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return netip.AddrPort{}, err
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}
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for _, message := range controlMessages {
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if message.Header.Level == unix.SOL_IP && message.Header.Type == unix.IP_RECVORIGDSTADDR {
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return netip.AddrPortFrom(M.AddrFromIP(message.Data[4:8]), binary.BigEndian.Uint16(message.Data[2:4])), nil
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} else if message.Header.Level == unix.SOL_IPV6 && message.Header.Type == unix.IPV6_RECVORIGDSTADDR {
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return netip.AddrPortFrom(M.AddrFromIP(message.Data[8:24]), binary.BigEndian.Uint16(message.Data[2:4])), nil
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}
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}
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return netip.AddrPort{}, E.New("not found")
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}
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func DialUDP(lAddr *net.UDPAddr, rAddr *net.UDPAddr) (*net.UDPConn, error) {
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rSockAddr, err := udpAddrToSockAddr(rAddr)
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if err != nil {
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return nil, err
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}
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lSockAddr, err := udpAddrToSockAddr(lAddr)
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if err != nil {
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return nil, err
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}
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fd, err := syscall.Socket(udpAddrFamily(lAddr, rAddr), syscall.SOCK_DGRAM, 0)
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if err != nil {
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return nil, err
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}
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if err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1); err != nil {
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syscall.Close(fd)
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return nil, err
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}
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if err = syscall.SetsockoptInt(fd, syscall.SOL_IP, syscall.IP_TRANSPARENT, 1); err != nil {
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syscall.Close(fd)
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return nil, err
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}
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if err = syscall.Bind(fd, lSockAddr); err != nil {
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syscall.Close(fd)
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return nil, err
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}
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if err = syscall.Connect(fd, rSockAddr); err != nil {
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syscall.Close(fd)
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return nil, err
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}
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fdFile := os.NewFile(uintptr(fd), F.ToString("net-udp-dial-", rAddr))
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defer fdFile.Close()
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c, err := net.FileConn(fdFile)
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if err != nil {
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syscall.Close(fd)
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return nil, err
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}
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return c.(*net.UDPConn), nil
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}
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func udpAddrToSockAddr(addr *net.UDPAddr) (syscall.Sockaddr, error) {
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switch {
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case addr.IP.To4() != nil:
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ip := [4]byte{}
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copy(ip[:], addr.IP.To4())
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return &syscall.SockaddrInet4{Addr: ip, Port: addr.Port}, nil
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default:
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ip := [16]byte{}
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copy(ip[:], addr.IP.To16())
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zoneID, err := strconv.ParseUint(addr.Zone, 10, 32)
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if err != nil {
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zoneID = 0
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}
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return &syscall.SockaddrInet6{Addr: ip, Port: addr.Port, ZoneId: uint32(zoneID)}, nil
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}
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}
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func udpAddrFamily(lAddr, rAddr *net.UDPAddr) int {
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if (lAddr == nil || lAddr.IP.To4() != nil) && (rAddr == nil || lAddr.IP.To4() != nil) {
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return syscall.AF_INET
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}
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return syscall.AF_INET6
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}
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