package quic import ( "context" "crypto/tls" "errors" "fmt" "net" "strings" "github.com/lucas-clemente/quic-go/internal/protocol" "github.com/lucas-clemente/quic-go/internal/utils" "github.com/lucas-clemente/quic-go/logging" ) type client struct { conn sendConn // If the client is created with DialAddr, we create a packet conn. // If it is started with Dial, we take a packet conn as a parameter. createdPacketConn bool use0RTT bool packetHandlers packetHandlerManager tlsConf *tls.Config config *Config srcConnID protocol.ConnectionID destConnID protocol.ConnectionID initialPacketNumber protocol.PacketNumber hasNegotiatedVersion bool version protocol.VersionNumber handshakeChan chan struct{} session quicSession tracer logging.ConnectionTracer tracingID uint64 logger utils.Logger } var ( // make it possible to mock connection ID generation in the tests generateConnectionID = protocol.GenerateConnectionID generateConnectionIDForInitial = protocol.GenerateConnectionIDForInitial ) // DialAddr establishes a new QUIC connection to a server. // It uses a new UDP connection and closes this connection when the QUIC session is closed. // The hostname for SNI is taken from the given address. // The tls.Config.CipherSuites allows setting of TLS 1.3 cipher suites. func DialAddr( addr string, tlsConf *tls.Config, config *Config, ) (Session, error) { return DialAddrContext(context.Background(), addr, tlsConf, config) } // DialAddrEarly establishes a new 0-RTT QUIC connection to a server. // It uses a new UDP connection and closes this connection when the QUIC session is closed. // The hostname for SNI is taken from the given address. // The tls.Config.CipherSuites allows setting of TLS 1.3 cipher suites. func DialAddrEarly( addr string, tlsConf *tls.Config, config *Config, ) (EarlySession, error) { return DialAddrEarlyContext(context.Background(), addr, tlsConf, config) } // DialAddrEarlyContext establishes a new 0-RTT QUIC connection to a server using provided context. // See DialAddrEarly for details func DialAddrEarlyContext( ctx context.Context, addr string, tlsConf *tls.Config, config *Config, ) (EarlySession, error) { sess, err := dialAddrContext(ctx, addr, tlsConf, config, true) if err != nil { return nil, err } utils.Logger.WithPrefix(utils.DefaultLogger, "client").Debugf("Returning early session") return sess, nil } // DialAddrContext establishes a new QUIC connection to a server using the provided context. // See DialAddr for details. func DialAddrContext( ctx context.Context, addr string, tlsConf *tls.Config, config *Config, ) (Session, error) { return dialAddrContext(ctx, addr, tlsConf, config, false) } func dialAddrContext( ctx context.Context, addr string, tlsConf *tls.Config, config *Config, use0RTT bool, ) (quicSession, error) { udpAddr, err := net.ResolveUDPAddr("udp", addr) if err != nil { return nil, err } udpConn, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.IPv4zero, Port: 0}) if err != nil { return nil, err } return dialContext(ctx, udpConn, udpAddr, addr, tlsConf, config, use0RTT, true) } // Dial establishes a new QUIC connection to a server using a net.PacketConn. If // the PacketConn satisfies the OOBCapablePacketConn interface (as a net.UDPConn // does), ECN and packet info support will be enabled. In this case, ReadMsgUDP // and WriteMsgUDP will be used instead of ReadFrom and WriteTo to read/write // packets. The same PacketConn can be used for multiple calls to Dial and // Listen, QUIC connection IDs are used for demultiplexing the different // connections. The host parameter is used for SNI. The tls.Config must define // an application protocol (using NextProtos). func Dial( pconn net.PacketConn, remoteAddr net.Addr, host string, tlsConf *tls.Config, config *Config, ) (Session, error) { return dialContext(context.Background(), pconn, remoteAddr, host, tlsConf, config, false, false) } // DialEarly establishes a new 0-RTT QUIC connection to a server using a net.PacketConn. // The same PacketConn can be used for multiple calls to Dial and Listen, // QUIC connection IDs are used for demultiplexing the different connections. // The host parameter is used for SNI. // The tls.Config must define an application protocol (using NextProtos). func DialEarly( pconn net.PacketConn, remoteAddr net.Addr, host string, tlsConf *tls.Config, config *Config, ) (EarlySession, error) { return DialEarlyContext(context.Background(), pconn, remoteAddr, host, tlsConf, config) } // DialEarlyContext establishes a new 0-RTT QUIC connection to a server using a net.PacketConn using the provided context. // See DialEarly for details. func DialEarlyContext( ctx context.Context, pconn net.PacketConn, remoteAddr net.Addr, host string, tlsConf *tls.Config, config *Config, ) (EarlySession, error) { return dialContext(ctx, pconn, remoteAddr, host, tlsConf, config, true, false) } // DialContext establishes a new QUIC connection to a server using a net.PacketConn using the provided context. // See Dial for details. func DialContext( ctx context.Context, pconn net.PacketConn, remoteAddr net.Addr, host string, tlsConf *tls.Config, config *Config, ) (Session, error) { return dialContext(ctx, pconn, remoteAddr, host, tlsConf, config, false, false) } func dialContext( ctx context.Context, pconn net.PacketConn, remoteAddr net.Addr, host string, tlsConf *tls.Config, config *Config, use0RTT bool, createdPacketConn bool, ) (quicSession, error) { if tlsConf == nil { return nil, errors.New("quic: tls.Config not set") } if err := validateConfig(config); err != nil { return nil, err } config = populateClientConfig(config, createdPacketConn) packetHandlers, err := getMultiplexer().AddConn(pconn, config.ConnectionIDLength, config.StatelessResetKey, config.Tracer) if err != nil { return nil, err } c, err := newClient(pconn, remoteAddr, config, tlsConf, host, use0RTT, createdPacketConn) if err != nil { return nil, err } c.packetHandlers = packetHandlers c.tracingID = nextSessionTracingID() if c.config.Tracer != nil { c.tracer = c.config.Tracer.TracerForConnection( context.WithValue(ctx, SessionTracingKey, c.tracingID), protocol.PerspectiveClient, c.destConnID, ) } if c.tracer != nil { c.tracer.StartedConnection(c.conn.LocalAddr(), c.conn.RemoteAddr(), c.srcConnID, c.destConnID) } if err := c.dial(ctx); err != nil { return nil, err } return c.session, nil } func newClient( pconn net.PacketConn, remoteAddr net.Addr, config *Config, tlsConf *tls.Config, host string, use0RTT bool, createdPacketConn bool, ) (*client, error) { if tlsConf == nil { tlsConf = &tls.Config{} } if tlsConf.ServerName == "" { sni := host if strings.IndexByte(sni, ':') != -1 { var err error sni, _, err = net.SplitHostPort(sni) if err != nil { return nil, err } } tlsConf.ServerName = sni } // check that all versions are actually supported if config != nil { for _, v := range config.Versions { if !protocol.IsValidVersion(v) { return nil, fmt.Errorf("%s is not a valid QUIC version", v) } } } srcConnID, err := generateConnectionID(config.ConnectionIDLength) if err != nil { return nil, err } destConnID, err := generateConnectionIDForInitial() if err != nil { return nil, err } c := &client{ srcConnID: srcConnID, destConnID: destConnID, conn: newSendPconn(pconn, remoteAddr), createdPacketConn: createdPacketConn, use0RTT: use0RTT, tlsConf: tlsConf, config: config, version: config.Versions[0], handshakeChan: make(chan struct{}), logger: utils.DefaultLogger.WithPrefix("client"), } return c, nil } func (c *client) dial(ctx context.Context) error { c.logger.Infof("Starting new connection to %s (%s -> %s), source connection ID %s, destination connection ID %s, version %s", c.tlsConf.ServerName, c.conn.LocalAddr(), c.conn.RemoteAddr(), c.srcConnID, c.destConnID, c.version) c.session = newClientSession( c.conn, c.packetHandlers, c.destConnID, c.srcConnID, c.config, c.tlsConf, c.initialPacketNumber, c.use0RTT, c.hasNegotiatedVersion, c.tracer, c.tracingID, c.logger, c.version, ) c.packetHandlers.Add(c.srcConnID, c.session) errorChan := make(chan error, 1) go func() { err := c.session.run() // returns as soon as the session is closed if e := (&errCloseForRecreating{}); !errors.As(err, &e) && c.createdPacketConn { c.packetHandlers.Destroy() } errorChan <- err }() // only set when we're using 0-RTT // Otherwise, earlySessionChan will be nil. Receiving from a nil chan blocks forever. var earlySessionChan <-chan struct{} if c.use0RTT { earlySessionChan = c.session.earlySessionReady() } select { case <-ctx.Done(): c.session.shutdown() return ctx.Err() case err := <-errorChan: var recreateErr *errCloseForRecreating if errors.As(err, &recreateErr) { c.initialPacketNumber = recreateErr.nextPacketNumber c.version = recreateErr.nextVersion c.hasNegotiatedVersion = true return c.dial(ctx) } return err case <-earlySessionChan: // ready to send 0-RTT data return nil case <-c.session.HandshakeComplete().Done(): // handshake successfully completed return nil } }