sing-box/transport/tuic/packet.go

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2023-07-23 06:42:19 +00:00
package tuic
import (
"bytes"
"context"
"encoding/binary"
"errors"
"io"
"math"
"net"
"os"
"sync"
"time"
"github.com/sagernet/quic-go"
"github.com/sagernet/sing/common"
"github.com/sagernet/sing/common/atomic"
"github.com/sagernet/sing/common/buf"
"github.com/sagernet/sing/common/cache"
M "github.com/sagernet/sing/common/metadata"
)
var udpMessagePool = sync.Pool{
New: func() interface{} {
return new(udpMessage)
},
}
func releaseMessages(messages []*udpMessage) {
for _, message := range messages {
if message != nil {
*message = udpMessage{}
udpMessagePool.Put(message)
}
}
}
type udpMessage struct {
sessionID uint16
packetID uint16
fragmentTotal uint8
fragmentID uint8
destination M.Socksaddr
dataLength uint16
data *buf.Buffer
}
func (m *udpMessage) release() {
*m = udpMessage{}
udpMessagePool.Put(m)
}
func (m *udpMessage) releaseMessage() {
m.data.Release()
m.release()
}
func (m *udpMessage) pack() *buf.Buffer {
buffer := buf.NewSize(m.headerSize() + m.data.Len())
common.Must(
buffer.WriteByte(Version),
buffer.WriteByte(CommandPacket),
binary.Write(buffer, binary.BigEndian, m.sessionID),
binary.Write(buffer, binary.BigEndian, m.packetID),
binary.Write(buffer, binary.BigEndian, m.fragmentTotal),
binary.Write(buffer, binary.BigEndian, m.fragmentID),
binary.Write(buffer, binary.BigEndian, uint16(m.data.Len())),
addressSerializer.WriteAddrPort(buffer, m.destination),
common.Error(buffer.Write(m.data.Bytes())),
)
return buffer
}
func (m *udpMessage) headerSize() int {
return 2 + 10 + addressSerializer.AddrPortLen(m.destination)
}
func fragUDPMessage(message *udpMessage, maxPacketSize int) []*udpMessage {
if message.data.Len() <= maxPacketSize {
return []*udpMessage{message}
}
var fragments []*udpMessage
originPacket := message.data.Bytes()
udpMTU := maxPacketSize - message.headerSize()
for remaining := len(originPacket); remaining > 0; remaining -= udpMTU {
fragment := udpMessagePool.Get().(*udpMessage)
*fragment = *message
if remaining > udpMTU {
fragment.data = buf.As(originPacket[:udpMTU])
originPacket = originPacket[udpMTU:]
} else {
fragment.data = buf.As(originPacket)
originPacket = nil
}
fragments = append(fragments, fragment)
}
fragmentTotal := uint16(len(fragments))
for index, fragment := range fragments {
fragment.fragmentID = uint8(index)
fragment.fragmentTotal = uint8(fragmentTotal)
if index > 0 {
fragment.destination = M.Socksaddr{}
}
}
return fragments
}
type udpPacketConn struct {
ctx context.Context
cancel common.ContextCancelCauseFunc
sessionID uint16
quicConn quic.Connection
data chan *udpMessage
udpStream bool
udpMTU int
packetId atomic.Uint32
closeOnce sync.Once
isServer bool
defragger *udpDefragger
onDestroy func()
}
func newUDPPacketConn(ctx context.Context, quicConn quic.Connection, udpStream bool, isServer bool, onDestroy func()) *udpPacketConn {
ctx, cancel := common.ContextWithCancelCause(ctx)
return &udpPacketConn{
ctx: ctx,
cancel: cancel,
quicConn: quicConn,
data: make(chan *udpMessage, 64),
udpStream: udpStream,
isServer: isServer,
defragger: newUDPDefragger(),
onDestroy: onDestroy,
}
}
func (c *udpPacketConn) ReadPacketThreadSafe() (buffer *buf.Buffer, destination M.Socksaddr, err error) {
select {
case p := <-c.data:
buffer = p.data
destination = p.destination
p.release()
return
case <-c.ctx.Done():
return nil, M.Socksaddr{}, io.ErrClosedPipe
}
}
func (c *udpPacketConn) ReadPacket(buffer *buf.Buffer) (destination M.Socksaddr, err error) {
select {
case p := <-c.data:
_, err = buffer.ReadOnceFrom(p.data)
destination = p.destination
p.releaseMessage()
return
case <-c.ctx.Done():
return M.Socksaddr{}, io.ErrClosedPipe
}
}
func (c *udpPacketConn) WaitReadPacket(newBuffer func() *buf.Buffer) (destination M.Socksaddr, err error) {
select {
case p := <-c.data:
_, err = newBuffer().ReadOnceFrom(p.data)
destination = p.destination
p.releaseMessage()
return
case <-c.ctx.Done():
return M.Socksaddr{}, io.ErrClosedPipe
}
}
func (c *udpPacketConn) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
select {
case pkt := <-c.data:
n = copy(p, pkt.data.Bytes())
if pkt.destination.IsFqdn() {
addr = pkt.destination
} else {
addr = pkt.destination.UDPAddr()
}
pkt.releaseMessage()
return n, addr, nil
case <-c.ctx.Done():
return 0, nil, io.ErrClosedPipe
}
}
func (c *udpPacketConn) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
defer buffer.Release()
select {
case <-c.ctx.Done():
return net.ErrClosed
default:
}
if buffer.Len() > 0xffff {
return quic.ErrMessageTooLarge(0xffff)
}
packetId := c.packetId.Add(1)
if packetId > math.MaxUint16 {
c.packetId.Store(0)
packetId = 0
}
message := udpMessagePool.Get().(*udpMessage)
*message = udpMessage{
sessionID: c.sessionID,
packetID: uint16(packetId),
fragmentTotal: 1,
destination: destination,
data: buffer,
}
defer message.releaseMessage()
var err error
if !c.udpStream && c.udpMTU > 0 && buffer.Len() > c.udpMTU {
err = c.writePackets(fragUDPMessage(message, c.udpMTU))
} else {
err = c.writePacket(message)
}
if err == nil {
return nil
}
var tooLargeErr quic.ErrMessageTooLarge
if !errors.As(err, &tooLargeErr) {
return err
}
c.udpMTU = int(tooLargeErr)
return c.writePackets(fragUDPMessage(message, c.udpMTU))
}
func (c *udpPacketConn) WriteTo(p []byte, addr net.Addr) (n int, err error) {
select {
case <-c.ctx.Done():
return 0, net.ErrClosed
default:
}
if len(p) > 0xffff {
return 0, quic.ErrMessageTooLarge(0xffff)
}
packetId := c.packetId.Add(1)
if packetId > math.MaxUint16 {
c.packetId.Store(0)
packetId = 0
}
message := udpMessagePool.Get().(*udpMessage)
*message = udpMessage{
sessionID: c.sessionID,
packetID: uint16(packetId),
fragmentTotal: 1,
destination: M.SocksaddrFromNet(addr),
data: buf.As(p),
}
if c.udpMTU > 0 && len(p) > c.udpMTU {
err = c.writePackets(fragUDPMessage(message, c.udpMTU))
if err == nil {
return len(p), nil
}
} else {
err = c.writePacket(message)
}
if err == nil {
return len(p), nil
}
var tooLargeErr quic.ErrMessageTooLarge
if !errors.As(err, &tooLargeErr) {
return
}
c.udpMTU = int(tooLargeErr)
err = c.writePackets(fragUDPMessage(message, c.udpMTU))
if err == nil {
return len(p), nil
}
return
}
func (c *udpPacketConn) inputPacket(message *udpMessage) {
if message.fragmentTotal <= 1 {
select {
case c.data <- message:
default:
}
} else {
newMessage := c.defragger.feed(message)
if newMessage != nil {
select {
case c.data <- newMessage:
default:
}
}
}
}
func (c *udpPacketConn) writePackets(messages []*udpMessage) error {
defer releaseMessages(messages)
for _, message := range messages {
err := c.writePacket(message)
if err != nil {
return err
}
}
return nil
}
func (c *udpPacketConn) writePacket(message *udpMessage) error {
if !c.udpStream {
buffer := message.pack()
err := c.quicConn.SendMessage(buffer.Bytes())
buffer.Release()
if err != nil {
return err
}
} else {
stream, err := c.quicConn.OpenUniStream()
if err != nil {
return err
}
buffer := message.pack()
_, err = stream.Write(buffer.Bytes())
buffer.Release()
stream.Close()
if err != nil {
return err
}
}
return nil
}
func (c *udpPacketConn) Close() error {
c.closeOnce.Do(func() {
c.closeWithError(os.ErrClosed)
c.onDestroy()
})
return nil
}
func (c *udpPacketConn) closeWithError(err error) {
c.cancel(err)
if !c.isServer {
buffer := buf.NewSize(4)
defer buffer.Release()
buffer.WriteByte(Version)
buffer.WriteByte(CommandDissociate)
binary.Write(buffer, binary.BigEndian, c.sessionID)
sendStream, openErr := c.quicConn.OpenUniStream()
if openErr != nil {
return
}
defer sendStream.Close()
sendStream.Write(buffer.Bytes())
}
}
func (c *udpPacketConn) LocalAddr() net.Addr {
return c.quicConn.LocalAddr()
}
func (c *udpPacketConn) SetDeadline(t time.Time) error {
return os.ErrInvalid
}
func (c *udpPacketConn) SetReadDeadline(t time.Time) error {
return os.ErrInvalid
}
func (c *udpPacketConn) SetWriteDeadline(t time.Time) error {
return os.ErrInvalid
}
type udpDefragger struct {
packetMap *cache.LruCache[uint16, *packetItem]
}
func newUDPDefragger() *udpDefragger {
return &udpDefragger{
packetMap: cache.New(
cache.WithAge[uint16, *packetItem](10),
cache.WithUpdateAgeOnGet[uint16, *packetItem](),
cache.WithEvict[uint16, *packetItem](func(key uint16, value *packetItem) {
releaseMessages(value.messages)
}),
),
}
}
type packetItem struct {
access sync.Mutex
messages []*udpMessage
count uint8
}
func (d *udpDefragger) feed(m *udpMessage) *udpMessage {
if m.fragmentTotal <= 1 {
return m
}
if m.fragmentID >= m.fragmentTotal {
return nil
}
item, _ := d.packetMap.LoadOrStore(m.packetID, newPacketItem)
item.access.Lock()
defer item.access.Unlock()
if int(m.fragmentTotal) != len(item.messages) {
releaseMessages(item.messages)
item.messages = make([]*udpMessage, m.fragmentTotal)
item.count = 1
item.messages[m.fragmentID] = m
return nil
}
if item.messages[m.fragmentID] != nil {
return nil
}
item.messages[m.fragmentID] = m
item.count++
if int(item.count) != len(item.messages) {
return nil
}
newMessage := udpMessagePool.Get().(*udpMessage)
*newMessage = *item.messages[0]
if m.dataLength > 0 {
newMessage.data = buf.NewSize(int(m.dataLength))
for _, message := range item.messages {
newMessage.data.Write(message.data.Bytes())
message.releaseMessage()
}
item.messages = nil
return newMessage
}
return nil
}
func newPacketItem() *packetItem {
return new(packetItem)
}
func readUDPMessage(message *udpMessage, reader io.Reader) error {
err := binary.Read(reader, binary.BigEndian, &message.sessionID)
if err != nil {
return err
}
err = binary.Read(reader, binary.BigEndian, &message.packetID)
if err != nil {
return err
}
err = binary.Read(reader, binary.BigEndian, &message.fragmentTotal)
if err != nil {
return err
}
err = binary.Read(reader, binary.BigEndian, &message.fragmentID)
if err != nil {
return err
}
err = binary.Read(reader, binary.BigEndian, &message.dataLength)
if err != nil {
return err
}
message.destination, err = addressSerializer.ReadAddrPort(reader)
if err != nil {
return err
}
message.data = buf.NewSize(int(message.dataLength))
_, err = message.data.ReadFullFrom(reader, message.data.FreeLen())
if err != nil {
return err
}
return nil
}
func decodeUDPMessage(message *udpMessage, data []byte) error {
reader := bytes.NewReader(data)
err := binary.Read(reader, binary.BigEndian, &message.sessionID)
if err != nil {
return err
}
err = binary.Read(reader, binary.BigEndian, &message.packetID)
if err != nil {
return err
}
err = binary.Read(reader, binary.BigEndian, &message.fragmentTotal)
if err != nil {
return err
}
err = binary.Read(reader, binary.BigEndian, &message.fragmentID)
if err != nil {
return err
}
err = binary.Read(reader, binary.BigEndian, &message.dataLength)
if err != nil {
return err
}
message.destination, err = addressSerializer.ReadAddrPort(reader)
if err != nil {
return err
}
if reader.Len() != int(message.dataLength) {
return io.ErrUnexpectedEOF
}
message.data = buf.As(data[len(data)-reader.Len():])
return nil
}