113 lines
2.9 KiB
Go
113 lines
2.9 KiB
Go
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package quic
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import (
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"sync"
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"github.com/lucas-clemente/quic-go/internal/protocol"
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"github.com/lucas-clemente/quic-go/internal/utils"
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)
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// A closedLocalSession is a session that we closed locally.
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// When receiving packets for such a session, we need to retransmit the packet containing the CONNECTION_CLOSE frame,
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// with an exponential backoff.
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type closedLocalSession struct {
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conn sendConn
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connClosePacket []byte
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closeOnce sync.Once
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closeChan chan struct{} // is closed when the session is closed or destroyed
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receivedPackets chan *receivedPacket
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counter uint64 // number of packets received
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perspective protocol.Perspective
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logger utils.Logger
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}
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var _ packetHandler = &closedLocalSession{}
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// newClosedLocalSession creates a new closedLocalSession and runs it.
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func newClosedLocalSession(
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conn sendConn,
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connClosePacket []byte,
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perspective protocol.Perspective,
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logger utils.Logger,
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) packetHandler {
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s := &closedLocalSession{
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conn: conn,
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connClosePacket: connClosePacket,
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perspective: perspective,
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logger: logger,
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closeChan: make(chan struct{}),
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receivedPackets: make(chan *receivedPacket, 64),
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}
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go s.run()
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return s
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}
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func (s *closedLocalSession) run() {
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for {
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select {
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case p := <-s.receivedPackets:
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s.handlePacketImpl(p)
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case <-s.closeChan:
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return
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}
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}
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}
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func (s *closedLocalSession) handlePacket(p *receivedPacket) {
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select {
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case s.receivedPackets <- p:
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default:
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}
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}
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func (s *closedLocalSession) handlePacketImpl(_ *receivedPacket) {
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s.counter++
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// exponential backoff
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// only send a CONNECTION_CLOSE for the 1st, 2nd, 4th, 8th, 16th, ... packet arriving
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for n := s.counter; n > 1; n = n / 2 {
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if n%2 != 0 {
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return
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}
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}
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s.logger.Debugf("Received %d packets after sending CONNECTION_CLOSE. Retransmitting.", s.counter)
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if err := s.conn.Write(s.connClosePacket); err != nil {
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s.logger.Debugf("Error retransmitting CONNECTION_CLOSE: %s", err)
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}
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}
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func (s *closedLocalSession) shutdown() {
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s.destroy(nil)
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}
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func (s *closedLocalSession) destroy(error) {
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s.closeOnce.Do(func() {
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close(s.closeChan)
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})
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}
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func (s *closedLocalSession) getPerspective() protocol.Perspective {
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return s.perspective
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}
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// A closedRemoteSession is a session that was closed remotely.
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// For such a session, we might receive reordered packets that were sent before the CONNECTION_CLOSE.
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// We can just ignore those packets.
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type closedRemoteSession struct {
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perspective protocol.Perspective
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}
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var _ packetHandler = &closedRemoteSession{}
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func newClosedRemoteSession(pers protocol.Perspective) packetHandler {
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return &closedRemoteSession{perspective: pers}
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}
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func (s *closedRemoteSession) handlePacket(*receivedPacket) {}
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func (s *closedRemoteSession) shutdown() {}
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func (s *closedRemoteSession) destroy(error) {}
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func (s *closedRemoteSession) getPerspective() protocol.Perspective { return s.perspective }
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