339 lines
9.5 KiB
Go
339 lines
9.5 KiB
Go
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package quic
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import (
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"bytes"
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"crypto/tls"
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"errors"
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"net"
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"sync"
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"time"
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"github.com/lucas-clemente/quic-go/crypto"
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"github.com/lucas-clemente/quic-go/handshake"
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"github.com/lucas-clemente/quic-go/internal/utils"
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"github.com/lucas-clemente/quic-go/protocol"
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"github.com/lucas-clemente/quic-go/qerr"
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)
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// packetHandler handles packets
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type packetHandler interface {
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Session
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handlePacket(*receivedPacket)
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run() error
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closeRemote(error)
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}
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// A Listener of QUIC
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type server struct {
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tlsConf *tls.Config
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config *Config
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conn net.PacketConn
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certChain crypto.CertChain
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scfg *handshake.ServerConfig
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sessions map[protocol.ConnectionID]packetHandler
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sessionsMutex sync.RWMutex
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deleteClosedSessionsAfter time.Duration
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serverError error
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sessionQueue chan Session
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errorChan chan struct{}
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newSession func(conn connection, v protocol.VersionNumber, connectionID protocol.ConnectionID, sCfg *handshake.ServerConfig, tlsConf *tls.Config, config *Config) (packetHandler, <-chan handshakeEvent, error)
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}
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var _ Listener = &server{}
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// ListenAddr creates a QUIC server listening on a given address.
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// The listener is not active until Serve() is called.
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// The tls.Config must not be nil, the quic.Config may be nil.
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func ListenAddr(addr string, tlsConf *tls.Config, config *Config) (Listener, error) {
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udpAddr, err := net.ResolveUDPAddr("udp", addr)
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if err != nil {
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return nil, err
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}
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conn, err := net.ListenUDP("udp", udpAddr)
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if err != nil {
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return nil, err
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}
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return Listen(conn, tlsConf, config)
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}
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// Listen listens for QUIC connections on a given net.PacketConn.
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// The listener is not active until Serve() is called.
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// The tls.Config must not be nil, the quic.Config may be nil.
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func Listen(conn net.PacketConn, tlsConf *tls.Config, config *Config) (Listener, error) {
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certChain := crypto.NewCertChain(tlsConf)
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kex, err := crypto.NewCurve25519KEX()
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if err != nil {
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return nil, err
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}
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scfg, err := handshake.NewServerConfig(kex, certChain)
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if err != nil {
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return nil, err
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}
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s := &server{
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conn: conn,
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tlsConf: tlsConf,
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config: populateServerConfig(config),
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certChain: certChain,
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scfg: scfg,
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sessions: map[protocol.ConnectionID]packetHandler{},
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newSession: newSession,
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deleteClosedSessionsAfter: protocol.ClosedSessionDeleteTimeout,
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sessionQueue: make(chan Session, 5),
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errorChan: make(chan struct{}),
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}
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go s.serve()
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return s, nil
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}
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var defaultAcceptSTK = func(clientAddr net.Addr, stk *STK) bool {
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if stk == nil {
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return false
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}
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if time.Now().After(stk.sentTime.Add(protocol.STKExpiryTime)) {
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return false
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}
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var sourceAddr string
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if udpAddr, ok := clientAddr.(*net.UDPAddr); ok {
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sourceAddr = udpAddr.IP.String()
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} else {
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sourceAddr = clientAddr.String()
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}
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return sourceAddr == stk.remoteAddr
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}
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// populateServerConfig populates fields in the quic.Config with their default values, if none are set
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// it may be called with nil
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func populateServerConfig(config *Config) *Config {
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if config == nil {
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config = &Config{}
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}
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versions := config.Versions
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if len(versions) == 0 {
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versions = protocol.SupportedVersions
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}
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vsa := defaultAcceptSTK
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if config.AcceptSTK != nil {
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vsa = config.AcceptSTK
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}
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handshakeTimeout := protocol.DefaultHandshakeTimeout
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if config.HandshakeTimeout != 0 {
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handshakeTimeout = config.HandshakeTimeout
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}
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maxReceiveStreamFlowControlWindow := config.MaxReceiveStreamFlowControlWindow
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if maxReceiveStreamFlowControlWindow == 0 {
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maxReceiveStreamFlowControlWindow = protocol.DefaultMaxReceiveStreamFlowControlWindowServer
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}
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maxReceiveConnectionFlowControlWindow := config.MaxReceiveConnectionFlowControlWindow
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if maxReceiveConnectionFlowControlWindow == 0 {
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maxReceiveConnectionFlowControlWindow = protocol.DefaultMaxReceiveConnectionFlowControlWindowServer
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}
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return &Config{
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Versions: versions,
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HandshakeTimeout: handshakeTimeout,
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AcceptSTK: vsa,
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MaxReceiveStreamFlowControlWindow: maxReceiveStreamFlowControlWindow,
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MaxReceiveConnectionFlowControlWindow: maxReceiveConnectionFlowControlWindow,
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}
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}
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// serve listens on an existing PacketConn
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func (s *server) serve() {
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for {
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data := getPacketBuffer()
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data = data[:protocol.MaxReceivePacketSize]
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// The packet size should not exceed protocol.MaxReceivePacketSize bytes
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// If it does, we only read a truncated packet, which will then end up undecryptable
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n, remoteAddr, err := s.conn.ReadFrom(data)
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if err != nil {
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s.serverError = err
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close(s.errorChan)
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_ = s.Close()
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return
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}
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data = data[:n]
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if err := s.handlePacket(s.conn, remoteAddr, data); err != nil {
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utils.Errorf("error handling packet: %s", err.Error())
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}
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}
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}
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// Accept returns newly openend sessions
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func (s *server) Accept() (Session, error) {
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var sess Session
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select {
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case sess = <-s.sessionQueue:
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return sess, nil
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case <-s.errorChan:
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return nil, s.serverError
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}
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}
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// Close the server
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func (s *server) Close() error {
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s.sessionsMutex.Lock()
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for _, session := range s.sessions {
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if session != nil {
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s.sessionsMutex.Unlock()
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_ = session.Close(nil)
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s.sessionsMutex.Lock()
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}
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}
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s.sessionsMutex.Unlock()
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if s.conn == nil {
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return nil
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}
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return s.conn.Close()
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}
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// Addr returns the server's network address
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func (s *server) Addr() net.Addr {
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return s.conn.LocalAddr()
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}
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func (s *server) handlePacket(pconn net.PacketConn, remoteAddr net.Addr, packet []byte) error {
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rcvTime := time.Now()
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r := bytes.NewReader(packet)
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hdr, err := ParsePublicHeader(r, protocol.PerspectiveClient)
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if err != nil {
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return qerr.Error(qerr.InvalidPacketHeader, err.Error())
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}
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hdr.Raw = packet[:len(packet)-r.Len()]
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s.sessionsMutex.RLock()
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session, ok := s.sessions[hdr.ConnectionID]
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s.sessionsMutex.RUnlock()
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// ignore all Public Reset packets
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if hdr.ResetFlag {
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if ok {
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var pr *publicReset
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pr, err = parsePublicReset(r)
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if err != nil {
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utils.Infof("Received a Public Reset for connection %x. An error occurred parsing the packet.")
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} else {
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utils.Infof("Received a Public Reset for connection %x, rejected packet number: 0x%x.", hdr.ConnectionID, pr.rejectedPacketNumber)
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}
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} else {
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utils.Infof("Received Public Reset for unknown connection %x.", hdr.ConnectionID)
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}
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return nil
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}
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// a session is only created once the client sent a supported version
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// if we receive a packet for a connection that already has session, it's probably an old packet that was sent by the client before the version was negotiated
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// it is safe to drop it
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if ok && hdr.VersionFlag && !protocol.IsSupportedVersion(s.config.Versions, hdr.VersionNumber) {
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return nil
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}
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// Send Version Negotiation Packet if the client is speaking a different protocol version
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if hdr.VersionFlag && !protocol.IsSupportedVersion(s.config.Versions, hdr.VersionNumber) {
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// drop packets that are too small to be valid first packets
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if len(packet) < protocol.ClientHelloMinimumSize+len(hdr.Raw) {
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return errors.New("dropping small packet with unknown version")
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}
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utils.Infof("Client offered version %d, sending VersionNegotiationPacket", hdr.VersionNumber)
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_, err = pconn.WriteTo(composeVersionNegotiation(hdr.ConnectionID, s.config.Versions), remoteAddr)
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return err
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}
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if !ok {
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if !hdr.VersionFlag {
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_, err = pconn.WriteTo(writePublicReset(hdr.ConnectionID, hdr.PacketNumber, 0), remoteAddr)
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return err
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}
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version := hdr.VersionNumber
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if !protocol.IsSupportedVersion(s.config.Versions, version) {
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return errors.New("Server BUG: negotiated version not supported")
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}
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utils.Infof("Serving new connection: %x, version %d from %v", hdr.ConnectionID, version, remoteAddr)
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var handshakeChan <-chan handshakeEvent
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session, handshakeChan, err = s.newSession(
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&conn{pconn: pconn, currentAddr: remoteAddr},
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version,
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hdr.ConnectionID,
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s.scfg,
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s.tlsConf,
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s.config,
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)
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if err != nil {
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return err
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}
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s.sessionsMutex.Lock()
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s.sessions[hdr.ConnectionID] = session
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s.sessionsMutex.Unlock()
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go func() {
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// session.run() returns as soon as the session is closed
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_ = session.run()
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s.removeConnection(hdr.ConnectionID)
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}()
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go func() {
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for {
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ev := <-handshakeChan
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if ev.err != nil {
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return
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}
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if ev.encLevel == protocol.EncryptionForwardSecure {
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break
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}
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}
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s.sessionQueue <- session
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}()
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}
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if session == nil {
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// Late packet for closed session
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return nil
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}
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session.handlePacket(&receivedPacket{
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remoteAddr: remoteAddr,
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publicHeader: hdr,
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data: packet[len(packet)-r.Len():],
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rcvTime: rcvTime,
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})
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return nil
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}
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func (s *server) removeConnection(id protocol.ConnectionID) {
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s.sessionsMutex.Lock()
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s.sessions[id] = nil
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s.sessionsMutex.Unlock()
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time.AfterFunc(s.deleteClosedSessionsAfter, func() {
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s.sessionsMutex.Lock()
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delete(s.sessions, id)
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s.sessionsMutex.Unlock()
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})
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}
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func composeVersionNegotiation(connectionID protocol.ConnectionID, versions []protocol.VersionNumber) []byte {
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fullReply := &bytes.Buffer{}
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responsePublicHeader := PublicHeader{
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ConnectionID: connectionID,
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PacketNumber: 1,
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VersionFlag: true,
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}
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err := responsePublicHeader.Write(fullReply, protocol.VersionWhatever, protocol.PerspectiveServer)
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if err != nil {
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utils.Errorf("error composing version negotiation packet: %s", err.Error())
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}
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for _, v := range versions {
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utils.WriteUint32(fullReply, protocol.VersionNumberToTag(v))
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}
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return fullReply.Bytes()
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}
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