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packet_handler_map.go
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/
packet_handler_map.go
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package quic
import (
"bytes"
"errors"
"fmt"
"net"
"sync"
"time"
"v2ray.com/core/external/github.com/lucas-clemente/quic-go/internal/protocol"
"v2ray.com/core/external/github.com/lucas-clemente/quic-go/internal/utils"
"v2ray.com/core/external/github.com/lucas-clemente/quic-go/internal/wire"
)
type packetHandlerEntry struct {
handler packetHandler
resetToken *[16]byte
}
// The packetHandlerMap stores packetHandlers, identified by connection ID.
// It is used:
// * by the server to store sessions
// * when multiplexing outgoing connections to store clients
type packetHandlerMap struct {
mutex sync.RWMutex
conn net.PacketConn
connIDLen int
handlers map[string] /* string(ConnectionID)*/ packetHandlerEntry
resetTokens map[[16]byte] /* stateless reset token */ packetHandler
server unknownPacketHandler
closed bool
deleteRetiredSessionsAfter time.Duration
logger utils.Logger
}
var _ packetHandlerManager = &packetHandlerMap{}
func newPacketHandlerMap(conn net.PacketConn, connIDLen int, logger utils.Logger) packetHandlerManager {
m := &packetHandlerMap{
conn: conn,
connIDLen: connIDLen,
handlers: make(map[string]packetHandlerEntry),
resetTokens: make(map[[16]byte]packetHandler),
deleteRetiredSessionsAfter: protocol.RetiredConnectionIDDeleteTimeout,
logger: logger,
}
go m.listen()
return m
}
func (h *packetHandlerMap) Add(id protocol.ConnectionID, handler packetHandler) {
h.mutex.Lock()
h.handlers[string(id)] = packetHandlerEntry{handler: handler}
h.mutex.Unlock()
}
func (h *packetHandlerMap) AddWithResetToken(id protocol.ConnectionID, handler packetHandler, token [16]byte) {
h.mutex.Lock()
h.handlers[string(id)] = packetHandlerEntry{handler: handler, resetToken: &token}
h.resetTokens[token] = handler
h.mutex.Unlock()
}
func (h *packetHandlerMap) Remove(id protocol.ConnectionID) {
h.removeByConnectionIDAsString(string(id))
}
func (h *packetHandlerMap) removeByConnectionIDAsString(id string) {
h.mutex.Lock()
if handlerEntry, ok := h.handlers[id]; ok {
if token := handlerEntry.resetToken; token != nil {
delete(h.resetTokens, *token)
}
delete(h.handlers, id)
}
h.mutex.Unlock()
}
func (h *packetHandlerMap) Retire(id protocol.ConnectionID) {
h.retireByConnectionIDAsString(string(id))
}
func (h *packetHandlerMap) retireByConnectionIDAsString(id string) {
time.AfterFunc(h.deleteRetiredSessionsAfter, func() {
h.removeByConnectionIDAsString(id)
})
}
func (h *packetHandlerMap) SetServer(s unknownPacketHandler) {
h.mutex.Lock()
h.server = s
h.mutex.Unlock()
}
func (h *packetHandlerMap) CloseServer() {
h.mutex.Lock()
h.server = nil
var wg sync.WaitGroup
for id, handlerEntry := range h.handlers {
handler := handlerEntry.handler
if handler.GetPerspective() == protocol.PerspectiveServer {
wg.Add(1)
go func(id string, handler packetHandler) {
// session.Close() blocks until the CONNECTION_CLOSE has been sent and the run-loop has stopped
_ = handler.Close()
h.retireByConnectionIDAsString(id)
wg.Done()
}(id, handler)
}
}
h.mutex.Unlock()
wg.Wait()
}
func (h *packetHandlerMap) close(e error) error {
h.mutex.Lock()
if h.closed {
h.mutex.Unlock()
return nil
}
h.closed = true
var wg sync.WaitGroup
for _, handlerEntry := range h.handlers {
wg.Add(1)
go func(handlerEntry packetHandlerEntry) {
handlerEntry.handler.destroy(e)
wg.Done()
}(handlerEntry)
}
if h.server != nil {
h.server.closeWithError(e)
}
h.mutex.Unlock()
wg.Wait()
return getMultiplexer().RemoveConn(h.conn)
}
func (h *packetHandlerMap) listen() {
for {
buffer := getPacketBuffer()
data := buffer.Slice
// The packet size should not exceed protocol.MaxReceivePacketSize bytes
// If it does, we only read a truncated packet, which will then end up undecryptable
n, addr, err := h.conn.ReadFrom(data)
if err != nil {
h.close(err)
return
}
h.handlePacket(addr, buffer, data[:n])
}
}
func (h *packetHandlerMap) handlePacket(
addr net.Addr,
buffer *packetBuffer,
data []byte,
) {
packets, err := h.parsePacket(addr, buffer, data)
if err != nil {
h.logger.Debugf("error parsing packets from %s: %s", addr, err)
// This is just the error from parsing the last packet.
// We still need to process the packets that were successfully parsed before.
}
if len(packets) == 0 {
buffer.Release()
return
}
h.handleParsedPackets(packets)
}
func (h *packetHandlerMap) parsePacket(
addr net.Addr,
buffer *packetBuffer,
data []byte,
) ([]*receivedPacket, error) {
rcvTime := time.Now()
packets := make([]*receivedPacket, 0, 1)
var counter int
var lastConnID protocol.ConnectionID
for len(data) > 0 {
hdr, err := wire.ParseHeader(bytes.NewReader(data), h.connIDLen)
// drop the packet if we can't parse the header
if err != nil {
return packets, fmt.Errorf("error parsing header: %s", err)
}
if counter > 0 && !hdr.DestConnectionID.Equal(lastConnID) {
return packets, fmt.Errorf("coalesced packet has different destination connection ID: %s, expected %s", hdr.DestConnectionID, lastConnID)
}
lastConnID = hdr.DestConnectionID
var rest []byte
if hdr.IsLongHeader {
if protocol.ByteCount(len(data)) < hdr.ParsedLen()+hdr.Length {
return packets, fmt.Errorf("packet length (%d bytes) is smaller than the expected length (%d bytes)", len(data)-int(hdr.ParsedLen()), hdr.Length)
}
packetLen := int(hdr.ParsedLen() + hdr.Length)
rest = data[packetLen:]
data = data[:packetLen]
}
if counter > 0 {
buffer.Split()
}
counter++
packets = append(packets, &receivedPacket{
remoteAddr: addr,
hdr: hdr,
rcvTime: rcvTime,
data: data,
buffer: buffer,
})
// only log if this actually a coalesced packet
if h.logger.Debug() && (counter > 1 || len(rest) > 0) {
h.logger.Debugf("Parsed a coalesced packet. Part %d: %d bytes. Remaining: %d bytes.", counter, len(packets[counter-1].data), len(rest))
}
data = rest
}
return packets, nil
}
func (h *packetHandlerMap) handleParsedPackets(packets []*receivedPacket) {
h.mutex.RLock()
defer h.mutex.RUnlock()
// coalesced packets all have the same destination connection ID
handlerEntry, handlerFound := h.handlers[string(packets[0].hdr.DestConnectionID)]
for _, p := range packets {
if handlerFound { // existing session
handlerEntry.handler.handlePacket(p)
continue
}
// No session found.
// This might be a stateless reset.
if !p.hdr.IsLongHeader {
if len(p.data) >= protocol.MinStatelessResetSize {
var token [16]byte
copy(token[:], p.data[len(p.data)-16:])
if sess, ok := h.resetTokens[token]; ok {
sess.destroy(errors.New("received a stateless reset"))
continue
}
}
// TODO(#943): send a stateless reset
h.logger.Debugf("received a short header packet with an unexpected connection ID %s", p.hdr.DestConnectionID)
break // a short header packet is always the last in a coalesced packet
}
if h.server == nil { // no server set
h.logger.Debugf("received a packet with an unexpected connection ID %s", p.hdr.DestConnectionID)
continue
}
h.server.handlePacket(p)
}
}