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server.go
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package quic
import (
"context"
"crypto/tls"
"errors"
"fmt"
"net"
"sync"
"sync/atomic"
"time"
"github.com/quic-go/quic-go/internal/handshake"
"github.com/quic-go/quic-go/internal/protocol"
"github.com/quic-go/quic-go/internal/qerr"
"github.com/quic-go/quic-go/internal/utils"
"github.com/quic-go/quic-go/internal/wire"
"github.com/quic-go/quic-go/logging"
)
// ErrServerClosed is returned by the Listener or EarlyListener's Accept method after a call to Close.
var ErrServerClosed = errors.New("quic: server closed")
// packetHandler handles packets
type packetHandler interface {
handlePacket(receivedPacket)
shutdown()
destroy(error)
getPerspective() protocol.Perspective
}
type packetHandlerManager interface {
Get(protocol.ConnectionID) (packetHandler, bool)
GetByResetToken(protocol.StatelessResetToken) (packetHandler, bool)
AddWithConnID(protocol.ConnectionID, protocol.ConnectionID, func() (packetHandler, bool)) bool
Close(error)
CloseServer()
connRunner
}
type quicConn interface {
EarlyConnection
earlyConnReady() <-chan struct{}
handlePacket(receivedPacket)
GetVersion() protocol.VersionNumber
getPerspective() protocol.Perspective
run() error
destroy(error)
shutdown()
}
type zeroRTTQueue struct {
packets []receivedPacket
expiration time.Time
}
type rejectedPacket struct {
receivedPacket
hdr *wire.Header
}
// A Listener of QUIC
type baseServer struct {
mutex sync.Mutex
disableVersionNegotiation bool
acceptEarlyConns bool
tlsConf *tls.Config
config *Config
conn rawConn
tokenGenerator *handshake.TokenGenerator
maxTokenAge time.Duration
connIDGenerator ConnectionIDGenerator
connHandler packetHandlerManager
onClose func()
receivedPackets chan receivedPacket
nextZeroRTTCleanup time.Time
zeroRTTQueues map[protocol.ConnectionID]*zeroRTTQueue // only initialized if acceptEarlyConns == true
// set as a member, so they can be set in the tests
newConn func(
sendConn,
connRunner,
protocol.ConnectionID, /* original dest connection ID */
*protocol.ConnectionID, /* retry src connection ID */
protocol.ConnectionID, /* client dest connection ID */
protocol.ConnectionID, /* destination connection ID */
protocol.ConnectionID, /* source connection ID */
ConnectionIDGenerator,
protocol.StatelessResetToken,
*Config,
*tls.Config,
*handshake.TokenGenerator,
bool, /* client address validated by an address validation token */
*logging.ConnectionTracer,
uint64,
utils.Logger,
protocol.VersionNumber,
) quicConn
serverError error
errorChan chan struct{}
closed bool
running chan struct{} // closed as soon as run() returns
versionNegotiationQueue chan receivedPacket
invalidTokenQueue chan rejectedPacket
connectionRefusedQueue chan rejectedPacket
retryQueue chan rejectedPacket
connQueue chan quicConn
connQueueLen int32 // to be used as an atomic
tracer *logging.Tracer
logger utils.Logger
}
// A Listener listens for incoming QUIC connections.
// It returns connections once the handshake has completed.
type Listener struct {
baseServer *baseServer
}
// Accept returns new connections. It should be called in a loop.
func (l *Listener) Accept(ctx context.Context) (Connection, error) {
return l.baseServer.Accept(ctx)
}
// Close the server. All active connections will be closed.
func (l *Listener) Close() error {
return l.baseServer.Close()
}
// Addr returns the local network address that the server is listening on.
func (l *Listener) Addr() net.Addr {
return l.baseServer.Addr()
}
// An EarlyListener listens for incoming QUIC connections, and returns them before the handshake completes.
// For connections that don't use 0-RTT, this allows the server to send 0.5-RTT data.
// This data is encrypted with forward-secure keys, however, the client's identity has not yet been verified.
// For connection using 0-RTT, this allows the server to accept and respond to streams that the client opened in the
// 0-RTT data it sent. Note that at this point during the handshake, the live-ness of the
// client has not yet been confirmed, and the 0-RTT data could have been replayed by an attacker.
type EarlyListener struct {
baseServer *baseServer
}
// Accept returns a new connections. It should be called in a loop.
func (l *EarlyListener) Accept(ctx context.Context) (EarlyConnection, error) {
return l.baseServer.accept(ctx)
}
// Close the server. All active connections will be closed.
func (l *EarlyListener) Close() error {
return l.baseServer.Close()
}
// Addr returns the local network addr that the server is listening on.
func (l *EarlyListener) Addr() net.Addr {
return l.baseServer.Addr()
}
// ListenAddr creates a QUIC server listening on a given address.
// See Listen for more details.
func ListenAddr(addr string, tlsConf *tls.Config, config *Config) (*Listener, error) {
conn, err := listenUDP(addr)
if err != nil {
return nil, err
}
return (&Transport{
Conn: conn,
createdConn: true,
isSingleUse: true,
}).Listen(tlsConf, config)
}
// ListenAddrEarly works like ListenAddr, but it returns connections before the handshake completes.
func ListenAddrEarly(addr string, tlsConf *tls.Config, config *Config) (*EarlyListener, error) {
conn, err := listenUDP(addr)
if err != nil {
return nil, err
}
return (&Transport{
Conn: conn,
createdConn: true,
isSingleUse: true,
}).ListenEarly(tlsConf, config)
}
func listenUDP(addr string) (*net.UDPConn, error) {
udpAddr, err := net.ResolveUDPAddr("udp", addr)
if err != nil {
return nil, err
}
return net.ListenUDP("udp", udpAddr)
}
// Listen listens for QUIC connections on a given 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.
// A single net.PacketConn can only be used for a single call to Listen.
//
// The tls.Config must not be nil and must contain a certificate configuration.
// Furthermore, it must define an application control (using NextProtos).
// The quic.Config may be nil, in that case the default values will be used.
//
// This is a convenience function. More advanced use cases should instantiate a Transport,
// which offers configuration options for a more fine-grained control of the connection establishment,
// including reusing the underlying UDP socket for outgoing QUIC connections.
func Listen(conn net.PacketConn, tlsConf *tls.Config, config *Config) (*Listener, error) {
tr := &Transport{Conn: conn, isSingleUse: true}
return tr.Listen(tlsConf, config)
}
// ListenEarly works like Listen, but it returns connections before the handshake completes.
func ListenEarly(conn net.PacketConn, tlsConf *tls.Config, config *Config) (*EarlyListener, error) {
tr := &Transport{Conn: conn, isSingleUse: true}
return tr.ListenEarly(tlsConf, config)
}
func newServer(
conn rawConn,
connHandler packetHandlerManager,
connIDGenerator ConnectionIDGenerator,
tlsConf *tls.Config,
config *Config,
tracer *logging.Tracer,
onClose func(),
tokenGeneratorKey TokenGeneratorKey,
maxTokenAge time.Duration,
disableVersionNegotiation bool,
acceptEarly bool,
) *baseServer {
s := &baseServer{
conn: conn,
tlsConf: tlsConf,
config: config,
tokenGenerator: handshake.NewTokenGenerator(tokenGeneratorKey),
maxTokenAge: maxTokenAge,
connIDGenerator: connIDGenerator,
connHandler: connHandler,
connQueue: make(chan quicConn),
errorChan: make(chan struct{}),
running: make(chan struct{}),
receivedPackets: make(chan receivedPacket, protocol.MaxServerUnprocessedPackets),
versionNegotiationQueue: make(chan receivedPacket, 4),
invalidTokenQueue: make(chan rejectedPacket, 4),
connectionRefusedQueue: make(chan rejectedPacket, 4),
retryQueue: make(chan rejectedPacket, 8),
newConn: newConnection,
tracer: tracer,
logger: utils.DefaultLogger.WithPrefix("server"),
acceptEarlyConns: acceptEarly,
disableVersionNegotiation: disableVersionNegotiation,
onClose: onClose,
}
if acceptEarly {
s.zeroRTTQueues = map[protocol.ConnectionID]*zeroRTTQueue{}
}
go s.run()
go s.runSendQueue()
s.logger.Debugf("Listening for %s connections on %s", conn.LocalAddr().Network(), conn.LocalAddr().String())
return s
}
func (s *baseServer) run() {
defer close(s.running)
for {
select {
case <-s.errorChan:
return
default:
}
select {
case <-s.errorChan:
return
case p := <-s.receivedPackets:
if bufferStillInUse := s.handlePacketImpl(p); !bufferStillInUse {
p.buffer.Release()
}
}
}
}
func (s *baseServer) runSendQueue() {
for {
select {
case <-s.running:
return
case p := <-s.versionNegotiationQueue:
s.maybeSendVersionNegotiationPacket(p)
case p := <-s.invalidTokenQueue:
s.maybeSendInvalidToken(p)
case p := <-s.connectionRefusedQueue:
s.sendConnectionRefused(p)
case p := <-s.retryQueue:
s.sendRetry(p)
}
}
}
// Accept returns connections that already completed the handshake.
// It is only valid if acceptEarlyConns is false.
func (s *baseServer) Accept(ctx context.Context) (Connection, error) {
return s.accept(ctx)
}
func (s *baseServer) accept(ctx context.Context) (quicConn, error) {
select {
case <-ctx.Done():
return nil, ctx.Err()
case conn := <-s.connQueue:
atomic.AddInt32(&s.connQueueLen, -1)
return conn, nil
case <-s.errorChan:
return nil, s.serverError
}
}
// Close the server
func (s *baseServer) Close() error {
s.mutex.Lock()
if s.closed {
s.mutex.Unlock()
return nil
}
if s.serverError == nil {
s.serverError = ErrServerClosed
}
s.closed = true
close(s.errorChan)
s.mutex.Unlock()
<-s.running
s.onClose()
return nil
}
func (s *baseServer) setCloseError(e error) {
s.mutex.Lock()
defer s.mutex.Unlock()
if s.closed {
return
}
s.closed = true
s.serverError = e
close(s.errorChan)
}
// Addr returns the server's network address
func (s *baseServer) Addr() net.Addr {
return s.conn.LocalAddr()
}
func (s *baseServer) handlePacket(p receivedPacket) {
select {
case s.receivedPackets <- p:
default:
s.logger.Debugf("Dropping packet from %s (%d bytes). Server receive queue full.", p.remoteAddr, p.Size())
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketTypeNotDetermined, p.Size(), logging.PacketDropDOSPrevention)
}
}
}
func (s *baseServer) handlePacketImpl(p receivedPacket) bool /* is the buffer still in use? */ {
if !s.nextZeroRTTCleanup.IsZero() && p.rcvTime.After(s.nextZeroRTTCleanup) {
defer s.cleanupZeroRTTQueues(p.rcvTime)
}
if wire.IsVersionNegotiationPacket(p.data) {
s.logger.Debugf("Dropping Version Negotiation packet.")
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketTypeVersionNegotiation, p.Size(), logging.PacketDropUnexpectedPacket)
}
return false
}
// Short header packets should never end up here in the first place
if !wire.IsLongHeaderPacket(p.data[0]) {
panic(fmt.Sprintf("misrouted packet: %#v", p.data))
}
v, err := wire.ParseVersion(p.data)
// drop the packet if we failed to parse the protocol version
if err != nil {
s.logger.Debugf("Dropping a packet with an unknown version")
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketTypeNotDetermined, p.Size(), logging.PacketDropUnexpectedPacket)
}
return false
}
// send a Version Negotiation Packet if the client is speaking a different protocol version
if !protocol.IsSupportedVersion(s.config.Versions, v) {
if s.disableVersionNegotiation {
return false
}
if p.Size() < protocol.MinUnknownVersionPacketSize {
s.logger.Debugf("Dropping a packet with an unsupported version number %d that is too small (%d bytes)", v, p.Size())
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketTypeNotDetermined, p.Size(), logging.PacketDropUnexpectedPacket)
}
return false
}
return s.enqueueVersionNegotiationPacket(p)
}
if wire.Is0RTTPacket(p.data) {
if !s.acceptEarlyConns {
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketType0RTT, p.Size(), logging.PacketDropUnexpectedPacket)
}
return false
}
return s.handle0RTTPacket(p)
}
// If we're creating a new connection, the packet will be passed to the connection.
// The header will then be parsed again.
hdr, _, _, err := wire.ParsePacket(p.data)
if err != nil {
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketTypeNotDetermined, p.Size(), logging.PacketDropHeaderParseError)
}
s.logger.Debugf("Error parsing packet: %s", err)
return false
}
if hdr.Type == protocol.PacketTypeInitial && p.Size() < protocol.MinInitialPacketSize {
s.logger.Debugf("Dropping a packet that is too small to be a valid Initial (%d bytes)", p.Size())
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketTypeInitial, p.Size(), logging.PacketDropUnexpectedPacket)
}
return false
}
if hdr.Type != protocol.PacketTypeInitial {
// Drop long header packets.
// There's little point in sending a Stateless Reset, since the client
// might not have received the token yet.
s.logger.Debugf("Dropping long header packet of type %s (%d bytes)", hdr.Type, len(p.data))
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketTypeFromHeader(hdr), p.Size(), logging.PacketDropUnexpectedPacket)
}
return false
}
s.logger.Debugf("<- Received Initial packet.")
if err := s.handleInitialImpl(p, hdr); err != nil {
s.logger.Errorf("Error occurred handling initial packet: %s", err)
}
// Don't put the packet buffer back.
// handleInitialImpl deals with the buffer.
return true
}
func (s *baseServer) handle0RTTPacket(p receivedPacket) bool {
connID, err := wire.ParseConnectionID(p.data, 0)
if err != nil {
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketType0RTT, p.Size(), logging.PacketDropHeaderParseError)
}
return false
}
// check again if we might have a connection now
if handler, ok := s.connHandler.Get(connID); ok {
handler.handlePacket(p)
return true
}
if q, ok := s.zeroRTTQueues[connID]; ok {
if len(q.packets) >= protocol.Max0RTTQueueLen {
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketType0RTT, p.Size(), logging.PacketDropDOSPrevention)
}
return false
}
q.packets = append(q.packets, p)
return true
}
if len(s.zeroRTTQueues) >= protocol.Max0RTTQueues {
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketType0RTT, p.Size(), logging.PacketDropDOSPrevention)
}
return false
}
queue := &zeroRTTQueue{packets: make([]receivedPacket, 1, 8)}
queue.packets[0] = p
expiration := p.rcvTime.Add(protocol.Max0RTTQueueingDuration)
queue.expiration = expiration
if s.nextZeroRTTCleanup.IsZero() || s.nextZeroRTTCleanup.After(expiration) {
s.nextZeroRTTCleanup = expiration
}
s.zeroRTTQueues[connID] = queue
return true
}
func (s *baseServer) cleanupZeroRTTQueues(now time.Time) {
// Iterate over all queues to find those that are expired.
// This is ok since we're placing a pretty low limit on the number of queues.
var nextCleanup time.Time
for connID, q := range s.zeroRTTQueues {
if q.expiration.After(now) {
if nextCleanup.IsZero() || nextCleanup.After(q.expiration) {
nextCleanup = q.expiration
}
continue
}
for _, p := range q.packets {
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketType0RTT, p.Size(), logging.PacketDropDOSPrevention)
}
p.buffer.Release()
}
delete(s.zeroRTTQueues, connID)
if s.logger.Debug() {
s.logger.Debugf("Removing 0-RTT queue for %s.", connID)
}
}
s.nextZeroRTTCleanup = nextCleanup
}
// validateToken returns false if:
// - address is invalid
// - token is expired
// - token is null
func (s *baseServer) validateToken(token *handshake.Token, addr net.Addr) bool {
if token == nil {
return false
}
if !token.ValidateRemoteAddr(addr) {
return false
}
if !token.IsRetryToken && time.Since(token.SentTime) > s.maxTokenAge {
return false
}
if token.IsRetryToken && time.Since(token.SentTime) > s.config.maxRetryTokenAge() {
return false
}
return true
}
func (s *baseServer) handleInitialImpl(p receivedPacket, hdr *wire.Header) error {
if len(hdr.Token) == 0 && hdr.DestConnectionID.Len() < protocol.MinConnectionIDLenInitial {
p.buffer.Release()
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketTypeInitial, p.Size(), logging.PacketDropUnexpectedPacket)
}
return errors.New("too short connection ID")
}
// The server queues packets for a while, and we might already have established a connection by now.
// This results in a second check in the connection map.
// That's ok since it's not the hot path (it's only taken by some Initial and 0-RTT packets).
if handler, ok := s.connHandler.Get(hdr.DestConnectionID); ok {
handler.handlePacket(p)
return nil
}
var (
token *handshake.Token
retrySrcConnID *protocol.ConnectionID
)
origDestConnID := hdr.DestConnectionID
if len(hdr.Token) > 0 {
tok, err := s.tokenGenerator.DecodeToken(hdr.Token)
if err == nil {
if tok.IsRetryToken {
origDestConnID = tok.OriginalDestConnectionID
retrySrcConnID = &tok.RetrySrcConnectionID
}
token = tok
}
}
clientAddrIsValid := s.validateToken(token, p.remoteAddr)
if token != nil && !clientAddrIsValid {
// For invalid and expired non-retry tokens, we don't send an INVALID_TOKEN error.
// We just ignore them, and act as if there was no token on this packet at all.
// This also means we might send a Retry later.
if !token.IsRetryToken {
token = nil
} else {
// For Retry tokens, we send an INVALID_ERROR if
// * the token is too old, or
// * the token is invalid, in case of a retry token.
select {
case s.invalidTokenQueue <- rejectedPacket{receivedPacket: p, hdr: hdr}:
default:
// drop packet if we can't send out the INVALID_TOKEN packets fast enough
p.buffer.Release()
}
return nil
}
}
if token == nil && s.config.RequireAddressValidation(p.remoteAddr) {
// Retry invalidates all 0-RTT packets sent.
delete(s.zeroRTTQueues, hdr.DestConnectionID)
select {
case s.retryQueue <- rejectedPacket{receivedPacket: p, hdr: hdr}:
default:
// drop packet if we can't send out Retry packets fast enough
p.buffer.Release()
}
return nil
}
if queueLen := atomic.LoadInt32(&s.connQueueLen); queueLen >= protocol.MaxAcceptQueueSize {
s.logger.Debugf("Rejecting new connection. Server currently busy. Accept queue length: %d (max %d)", queueLen, protocol.MaxAcceptQueueSize)
select {
case s.connectionRefusedQueue <- rejectedPacket{receivedPacket: p, hdr: hdr}:
default:
// drop packet if we can't send out the CONNECTION_REFUSED fast enough
p.buffer.Release()
}
return nil
}
connID, err := s.connIDGenerator.GenerateConnectionID()
if err != nil {
return err
}
s.logger.Debugf("Changing connection ID to %s.", connID)
var conn quicConn
tracingID := nextConnTracingID()
if added := s.connHandler.AddWithConnID(hdr.DestConnectionID, connID, func() (packetHandler, bool) {
config := s.config
if s.config.GetConfigForClient != nil {
conf, err := s.config.GetConfigForClient(&ClientHelloInfo{RemoteAddr: p.remoteAddr})
if err != nil {
s.logger.Debugf("Rejecting new connection due to GetConfigForClient callback")
return nil, false
}
config = populateConfig(conf)
}
var tracer *logging.ConnectionTracer
if config.Tracer != nil {
// Use the same connection ID that is passed to the client's GetLogWriter callback.
connID := hdr.DestConnectionID
if origDestConnID.Len() > 0 {
connID = origDestConnID
}
tracer = config.Tracer(context.WithValue(context.Background(), ConnectionTracingKey, tracingID), protocol.PerspectiveServer, connID)
}
conn = s.newConn(
newSendConn(s.conn, p.remoteAddr, p.info, s.logger),
s.connHandler,
origDestConnID,
retrySrcConnID,
hdr.DestConnectionID,
hdr.SrcConnectionID,
connID,
s.connIDGenerator,
s.connHandler.GetStatelessResetToken(connID),
config,
s.tlsConf,
s.tokenGenerator,
clientAddrIsValid,
tracer,
tracingID,
s.logger,
hdr.Version,
)
conn.handlePacket(p)
if q, ok := s.zeroRTTQueues[hdr.DestConnectionID]; ok {
for _, p := range q.packets {
conn.handlePacket(p)
}
delete(s.zeroRTTQueues, hdr.DestConnectionID)
}
return conn, true
}); !added {
select {
case s.connectionRefusedQueue <- rejectedPacket{receivedPacket: p, hdr: hdr}:
default:
// drop packet if we can't send out the CONNECTION_REFUSED fast enough
p.buffer.Release()
}
return nil
}
go conn.run()
go s.handleNewConn(conn)
if conn == nil {
p.buffer.Release()
return nil
}
return nil
}
func (s *baseServer) handleNewConn(conn quicConn) {
connCtx := conn.Context()
if s.acceptEarlyConns {
// wait until the early connection is ready (or the handshake fails)
select {
case <-conn.earlyConnReady():
case <-connCtx.Done():
return
}
} else {
// wait until the handshake is complete (or fails)
select {
case <-conn.HandshakeComplete():
case <-connCtx.Done():
return
}
}
atomic.AddInt32(&s.connQueueLen, 1)
select {
case s.connQueue <- conn:
// blocks until the connection is accepted
case <-connCtx.Done():
atomic.AddInt32(&s.connQueueLen, -1)
// don't pass connections that were already closed to Accept()
}
}
func (s *baseServer) sendRetry(p rejectedPacket) {
if err := s.sendRetryPacket(p); err != nil {
s.logger.Debugf("Error sending Retry packet: %s", err)
}
}
func (s *baseServer) sendRetryPacket(p rejectedPacket) error {
hdr := p.hdr
// Log the Initial packet now.
// If no Retry is sent, the packet will be logged by the connection.
(&wire.ExtendedHeader{Header: *hdr}).Log(s.logger)
srcConnID, err := s.connIDGenerator.GenerateConnectionID()
if err != nil {
return err
}
token, err := s.tokenGenerator.NewRetryToken(p.remoteAddr, hdr.DestConnectionID, srcConnID)
if err != nil {
return err
}
replyHdr := &wire.ExtendedHeader{}
replyHdr.Type = protocol.PacketTypeRetry
replyHdr.Version = hdr.Version
replyHdr.SrcConnectionID = srcConnID
replyHdr.DestConnectionID = hdr.SrcConnectionID
replyHdr.Token = token
if s.logger.Debug() {
s.logger.Debugf("Changing connection ID to %s.", srcConnID)
s.logger.Debugf("-> Sending Retry")
replyHdr.Log(s.logger)
}
buf := getPacketBuffer()
defer buf.Release()
buf.Data, err = replyHdr.Append(buf.Data, hdr.Version)
if err != nil {
return err
}
// append the Retry integrity tag
tag := handshake.GetRetryIntegrityTag(buf.Data, hdr.DestConnectionID, hdr.Version)
buf.Data = append(buf.Data, tag[:]...)
if s.tracer != nil && s.tracer.SentPacket != nil {
s.tracer.SentPacket(p.remoteAddr, &replyHdr.Header, protocol.ByteCount(len(buf.Data)), nil)
}
_, err = s.conn.WritePacket(buf.Data, p.remoteAddr, p.info.OOB(), 0, protocol.ECNUnsupported)
return err
}
func (s *baseServer) maybeSendInvalidToken(p rejectedPacket) {
defer p.buffer.Release()
// Only send INVALID_TOKEN if we can unprotect the packet.
// This makes sure that we won't send it for packets that were corrupted.
hdr := p.hdr
sealer, opener := handshake.NewInitialAEAD(hdr.DestConnectionID, protocol.PerspectiveServer, hdr.Version)
data := p.data[:hdr.ParsedLen()+hdr.Length]
extHdr, err := unpackLongHeader(opener, hdr, data, hdr.Version)
// Only send INVALID_TOKEN if we can unprotect the packet.
// This makes sure that we won't send it for packets that were corrupted.
if err != nil {
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketTypeInitial, p.Size(), logging.PacketDropHeaderParseError)
}
return
}
hdrLen := extHdr.ParsedLen()
if _, err := opener.Open(data[hdrLen:hdrLen], data[hdrLen:], extHdr.PacketNumber, data[:hdrLen]); err != nil {
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketTypeInitial, p.Size(), logging.PacketDropPayloadDecryptError)
}
return
}
if s.logger.Debug() {
s.logger.Debugf("Client sent an invalid retry token. Sending INVALID_TOKEN to %s.", p.remoteAddr)
}
if err := s.sendError(p.remoteAddr, hdr, sealer, qerr.InvalidToken, p.info); err != nil {
s.logger.Debugf("Error sending INVALID_TOKEN error: %s", err)
}
}
func (s *baseServer) sendConnectionRefused(p rejectedPacket) {
defer p.buffer.Release()
sealer, _ := handshake.NewInitialAEAD(p.hdr.DestConnectionID, protocol.PerspectiveServer, p.hdr.Version)
if err := s.sendError(p.remoteAddr, p.hdr, sealer, qerr.ConnectionRefused, p.info); err != nil {
s.logger.Debugf("Error sending CONNECTION_REFUSED error: %s", err)
}
}
// sendError sends the error as a response to the packet received with header hdr
func (s *baseServer) sendError(remoteAddr net.Addr, hdr *wire.Header, sealer handshake.LongHeaderSealer, errorCode qerr.TransportErrorCode, info packetInfo) error {
b := getPacketBuffer()
defer b.Release()
ccf := &wire.ConnectionCloseFrame{ErrorCode: uint64(errorCode)}
replyHdr := &wire.ExtendedHeader{}
replyHdr.Type = protocol.PacketTypeInitial
replyHdr.Version = hdr.Version
replyHdr.SrcConnectionID = hdr.DestConnectionID
replyHdr.DestConnectionID = hdr.SrcConnectionID
replyHdr.PacketNumberLen = protocol.PacketNumberLen4
replyHdr.Length = 4 /* packet number len */ + ccf.Length(hdr.Version) + protocol.ByteCount(sealer.Overhead())
var err error
b.Data, err = replyHdr.Append(b.Data, hdr.Version)
if err != nil {
return err
}
payloadOffset := len(b.Data)
b.Data, err = ccf.Append(b.Data, hdr.Version)
if err != nil {
return err
}
_ = sealer.Seal(b.Data[payloadOffset:payloadOffset], b.Data[payloadOffset:], replyHdr.PacketNumber, b.Data[:payloadOffset])
b.Data = b.Data[0 : len(b.Data)+sealer.Overhead()]
pnOffset := payloadOffset - int(replyHdr.PacketNumberLen)
sealer.EncryptHeader(
b.Data[pnOffset+4:pnOffset+4+16],
&b.Data[0],
b.Data[pnOffset:payloadOffset],
)
replyHdr.Log(s.logger)
wire.LogFrame(s.logger, ccf, true)
if s.tracer != nil && s.tracer.SentPacket != nil {
s.tracer.SentPacket(remoteAddr, &replyHdr.Header, protocol.ByteCount(len(b.Data)), []logging.Frame{ccf})
}
_, err = s.conn.WritePacket(b.Data, remoteAddr, info.OOB(), 0, protocol.ECNUnsupported)
return err
}
func (s *baseServer) enqueueVersionNegotiationPacket(p receivedPacket) (bufferInUse bool) {
select {
case s.versionNegotiationQueue <- p:
return true
default:
// it's fine to not send version negotiation packets when we are busy
}
return false
}
func (s *baseServer) maybeSendVersionNegotiationPacket(p receivedPacket) {
defer p.buffer.Release()
v, err := wire.ParseVersion(p.data)
if err != nil {
s.logger.Debugf("failed to parse version for sending version negotiation packet: %s", err)
return
}
_, src, dest, err := wire.ParseArbitraryLenConnectionIDs(p.data)
if err != nil { // should never happen
s.logger.Debugf("Dropping a packet with an unknown version for which we failed to parse connection IDs")
if s.tracer != nil && s.tracer.DroppedPacket != nil {
s.tracer.DroppedPacket(p.remoteAddr, logging.PacketTypeNotDetermined, p.Size(), logging.PacketDropUnexpectedPacket)
}
return
}
s.logger.Debugf("Client offered version %s, sending Version Negotiation", v)
data := wire.ComposeVersionNegotiation(dest, src, s.config.Versions)
if s.tracer != nil && s.tracer.SentVersionNegotiationPacket != nil {
s.tracer.SentVersionNegotiationPacket(p.remoteAddr, src, dest, s.config.Versions)
}
if _, err := s.conn.WritePacket(data, p.remoteAddr, p.info.OOB(), 0, protocol.ECNUnsupported); err != nil {
s.logger.Debugf("Error sending Version Negotiation: %s", err)
}
}