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xudp.go
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xudp.go
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package xudp
import (
"io"
"github.com/xtls/xray-core/common/buf"
"github.com/xtls/xray-core/common/net"
"github.com/xtls/xray-core/common/protocol"
)
var addrParser = protocol.NewAddressParser(
protocol.AddressFamilyByte(byte(protocol.AddressTypeIPv4), net.AddressFamilyIPv4),
protocol.AddressFamilyByte(byte(protocol.AddressTypeDomain), net.AddressFamilyDomain),
protocol.AddressFamilyByte(byte(protocol.AddressTypeIPv6), net.AddressFamilyIPv6),
protocol.PortThenAddress(),
)
func NewPacketWriter(writer buf.Writer, dest net.Destination) *PacketWriter {
return &PacketWriter{
Writer: writer,
Dest: dest,
}
}
type PacketWriter struct {
Writer buf.Writer
Dest net.Destination
}
func (w *PacketWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
defer buf.ReleaseMulti(mb)
mb2Write := make(buf.MultiBuffer, 0, len(mb))
for _, b := range mb {
length := b.Len()
if length == 0 || length+666 > buf.Size {
continue
}
eb := buf.New()
eb.Write([]byte{0, 0, 0, 0})
if w.Dest.Network == net.Network_UDP {
eb.WriteByte(1) // New
eb.WriteByte(1) // Opt
eb.WriteByte(2) // UDP
addrParser.WriteAddressPort(eb, w.Dest.Address, w.Dest.Port)
w.Dest.Network = net.Network_Unknown
} else {
eb.WriteByte(2) // Keep
eb.WriteByte(1)
if b.UDP != nil {
eb.WriteByte(2)
addrParser.WriteAddressPort(eb, b.UDP.Address, b.UDP.Port)
}
}
l := eb.Len() - 2
eb.SetByte(0, byte(l>>8))
eb.SetByte(1, byte(l))
eb.WriteByte(byte(length >> 8))
eb.WriteByte(byte(length))
eb.Write(b.Bytes())
mb2Write = append(mb2Write, eb)
}
if mb2Write.IsEmpty() {
return nil
}
return w.Writer.WriteMultiBuffer(mb2Write)
}
func NewPacketReader(reader io.Reader) *PacketReader {
return &PacketReader{
Reader: reader,
cache: make([]byte, 2),
}
}
type PacketReader struct {
Reader io.Reader
cache []byte
}
func (r *PacketReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
for {
if _, err := io.ReadFull(r.Reader, r.cache); err != nil {
return nil, err
}
l := int32(r.cache[0])<<8 | int32(r.cache[1])
if l < 4 {
return nil, io.EOF
}
b := buf.New()
if _, err := b.ReadFullFrom(r.Reader, l); err != nil {
b.Release()
return nil, err
}
discard := false
switch b.Byte(2) {
case 2:
if l != 4 {
b.Advance(5)
addr, port, err := addrParser.ReadAddressPort(nil, b)
if err != nil {
b.Release()
return nil, err
}
b.UDP = &net.Destination{
Network: net.Network_UDP,
Address: addr,
Port: port,
}
}
case 4:
discard = true
default:
b.Release()
return nil, io.EOF
}
if b.Byte(3) == 1 {
if _, err := io.ReadFull(r.Reader, r.cache); err != nil {
b.Release()
return nil, err
}
length := int32(r.cache[0])<<8 | int32(r.cache[1])
if length > 0 {
b.Clear()
if _, err := b.ReadFullFrom(r.Reader, length); err != nil {
b.Release()
return nil, err
}
if !discard {
return buf.MultiBuffer{b}, nil
}
}
}
b.Release()
}
}