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server.go
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server.go
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package quic
import (
"bytes"
"crypto/tls"
"errors"
"fmt"
"io"
"net"
"sync"
"sync/atomic"
"time"
"v2ray.com/core/external/github.com/lucas-clemente/quic-go/internal/handshake"
"v2ray.com/core/external/github.com/lucas-clemente/quic-go/internal/protocol"
"v2ray.com/core/external/github.com/lucas-clemente/quic-go/internal/qerr"
"v2ray.com/core/external/github.com/lucas-clemente/quic-go/internal/utils"
"v2ray.com/core/external/github.com/lucas-clemente/quic-go/internal/wire"
)
// packetHandler handles packets
type packetHandler interface {
handlePacket(*receivedPacket)
io.Closer
destroy(error)
GetPerspective() protocol.Perspective
}
type unknownPacketHandler interface {
handlePacket(*receivedPacket)
closeWithError(error) error
}
type packetHandlerManager interface {
Add(protocol.ConnectionID, packetHandler)
Retire(protocol.ConnectionID)
Remove(protocol.ConnectionID)
SetServer(unknownPacketHandler)
CloseServer()
}
type quicSession interface {
Session
handlePacket(*receivedPacket)
GetVersion() protocol.VersionNumber
run() error
destroy(error)
closeForRecreating() protocol.PacketNumber
closeRemote(error)
}
type sessionRunner interface {
onHandshakeComplete(Session)
retireConnectionID(protocol.ConnectionID)
removeConnectionID(protocol.ConnectionID)
}
type runner struct {
onHandshakeCompleteImpl func(Session)
retireConnectionIDImpl func(protocol.ConnectionID)
removeConnectionIDImpl func(protocol.ConnectionID)
}
func (r *runner) onHandshakeComplete(s Session) { r.onHandshakeCompleteImpl(s) }
func (r *runner) retireConnectionID(c protocol.ConnectionID) { r.retireConnectionIDImpl(c) }
func (r *runner) removeConnectionID(c protocol.ConnectionID) { r.removeConnectionIDImpl(c) }
var _ sessionRunner = &runner{}
// A Listener of QUIC
type server struct {
mutex sync.Mutex
tlsConf *tls.Config
config *Config
conn net.PacketConn
// If the server is started with ListenAddr, we create a packet conn.
// If it is started with Listen, we take a packet conn as a parameter.
createdPacketConn bool
cookieGenerator *handshake.CookieGenerator
sessionHandler packetHandlerManager
// set as a member, so they can be set in the tests
newSession func(connection, sessionRunner, protocol.ConnectionID /* original connection ID */, protocol.ConnectionID /* destination connection ID */, protocol.ConnectionID /* source connection ID */, *Config, *tls.Config, *handshake.TransportParameters, utils.Logger, protocol.VersionNumber) (quicSession, error)
serverError error
errorChan chan struct{}
closed bool
sessionQueue chan Session
sessionQueueLen int32 // to be used as an atomic
sessionRunner sessionRunner
logger utils.Logger
}
var _ Listener = &server{}
var _ unknownPacketHandler = &server{}
// ListenAddr creates a QUIC server listening on a given address.
// The tls.Config must not be nil and must contain a certificate configuration.
// The quic.Config may be nil, in that case the default values will be used.
func ListenAddr(addr string, tlsConf *tls.Config, config *Config) (Listener, error) {
udpAddr, err := net.ResolveUDPAddr("udp", addr)
if err != nil {
return nil, err
}
conn, err := net.ListenUDP("udp", udpAddr)
if err != nil {
return nil, err
}
serv, err := listen(conn, tlsConf, config)
if err != nil {
return nil, err
}
serv.createdPacketConn = true
return serv, nil
}
// Listen listens for QUIC connections on a given net.PacketConn.
// A single PacketConn only be used for a single call to Listen.
// The PacketConn can be used for simultaneous calls to Dial.
// QUIC connection IDs are used for demultiplexing the different connections.
// The tls.Config must not be nil and must contain a certificate configuration.
// The quic.Config may be nil, in that case the default values will be used.
func Listen(conn net.PacketConn, tlsConf *tls.Config, config *Config) (Listener, error) {
return listen(conn, tlsConf, config)
}
func listen(conn net.PacketConn, tlsConf *tls.Config, config *Config) (*server, error) {
// TODO(#1655): only require that tls.Config.Certificates or tls.Config.GetCertificate is set
if tlsConf == nil || len(tlsConf.Certificates) == 0 {
return nil, errors.New("quic: Certificates not set in tls.Config")
}
config = populateServerConfig(config)
for _, v := range config.Versions {
if !protocol.IsValidVersion(v) {
return nil, fmt.Errorf("%s is not a valid QUIC version", v)
}
}
sessionHandler, err := getMultiplexer().AddConn(conn, config.ConnectionIDLength)
if err != nil {
return nil, err
}
s := &server{
conn: conn,
tlsConf: tlsConf,
config: config,
sessionHandler: sessionHandler,
sessionQueue: make(chan Session),
errorChan: make(chan struct{}),
newSession: newSession,
logger: utils.DefaultLogger.WithPrefix("server"),
}
if err := s.setup(); err != nil {
return nil, err
}
sessionHandler.SetServer(s)
s.logger.Debugf("Listening for %s connections on %s", conn.LocalAddr().Network(), conn.LocalAddr().String())
return s, nil
}
func (s *server) setup() error {
s.sessionRunner = &runner{
onHandshakeCompleteImpl: func(sess Session) {
go func() {
atomic.AddInt32(&s.sessionQueueLen, 1)
defer atomic.AddInt32(&s.sessionQueueLen, -1)
select {
case s.sessionQueue <- sess:
// blocks until the session is accepted
case <-sess.Context().Done():
// don't pass sessions that were already closed to Accept()
}
}()
},
retireConnectionIDImpl: s.sessionHandler.Retire,
removeConnectionIDImpl: s.sessionHandler.Remove,
}
cookieGenerator, err := handshake.NewCookieGenerator()
if err != nil {
return err
}
s.cookieGenerator = cookieGenerator
return nil
}
var defaultAcceptCookie = func(clientAddr net.Addr, cookie *Cookie) bool {
if cookie == nil {
return false
}
if time.Now().After(cookie.SentTime.Add(protocol.CookieExpiryTime)) {
return false
}
var sourceAddr string
if udpAddr, ok := clientAddr.(*net.UDPAddr); ok {
sourceAddr = udpAddr.IP.String()
} else {
sourceAddr = clientAddr.String()
}
return sourceAddr == cookie.RemoteAddr
}
// populateServerConfig populates fields in the quic.Config with their default values, if none are set
// it may be called with nil
func populateServerConfig(config *Config) *Config {
if config == nil {
config = &Config{}
}
versions := config.Versions
if len(versions) == 0 {
versions = protocol.SupportedVersions
}
vsa := defaultAcceptCookie
if config.AcceptCookie != nil {
vsa = config.AcceptCookie
}
handshakeTimeout := protocol.DefaultHandshakeTimeout
if config.HandshakeTimeout != 0 {
handshakeTimeout = config.HandshakeTimeout
}
idleTimeout := protocol.DefaultIdleTimeout
if config.IdleTimeout != 0 {
idleTimeout = config.IdleTimeout
}
maxReceiveStreamFlowControlWindow := config.MaxReceiveStreamFlowControlWindow
if maxReceiveStreamFlowControlWindow == 0 {
maxReceiveStreamFlowControlWindow = protocol.DefaultMaxReceiveStreamFlowControlWindow
}
maxReceiveConnectionFlowControlWindow := config.MaxReceiveConnectionFlowControlWindow
if maxReceiveConnectionFlowControlWindow == 0 {
maxReceiveConnectionFlowControlWindow = protocol.DefaultMaxReceiveConnectionFlowControlWindow
}
maxIncomingStreams := config.MaxIncomingStreams
if maxIncomingStreams == 0 {
maxIncomingStreams = protocol.DefaultMaxIncomingStreams
} else if maxIncomingStreams < 0 {
maxIncomingStreams = 0
}
maxIncomingUniStreams := config.MaxIncomingUniStreams
if maxIncomingUniStreams == 0 {
maxIncomingUniStreams = protocol.DefaultMaxIncomingUniStreams
} else if maxIncomingUniStreams < 0 {
maxIncomingUniStreams = 0
}
connIDLen := config.ConnectionIDLength
if connIDLen == 0 {
connIDLen = protocol.DefaultConnectionIDLength
}
return &Config{
Versions: versions,
HandshakeTimeout: handshakeTimeout,
IdleTimeout: idleTimeout,
AcceptCookie: vsa,
KeepAlive: config.KeepAlive,
MaxReceiveStreamFlowControlWindow: maxReceiveStreamFlowControlWindow,
MaxReceiveConnectionFlowControlWindow: maxReceiveConnectionFlowControlWindow,
MaxIncomingStreams: maxIncomingStreams,
MaxIncomingUniStreams: maxIncomingUniStreams,
ConnectionIDLength: connIDLen,
}
}
// Accept returns newly openend sessions
func (s *server) Accept() (Session, error) {
var sess Session
select {
case sess = <-s.sessionQueue:
return sess, nil
case <-s.errorChan:
return nil, s.serverError
}
}
// Close the server
func (s *server) Close() error {
s.mutex.Lock()
defer s.mutex.Unlock()
if s.closed {
return nil
}
return s.closeWithMutex()
}
func (s *server) closeWithMutex() error {
s.sessionHandler.CloseServer()
if s.serverError == nil {
s.serverError = errors.New("server closed")
}
var err error
// If the server was started with ListenAddr, we created the packet conn.
// We need to close it in order to make the go routine reading from that conn return.
if s.createdPacketConn {
err = s.conn.Close()
}
s.closed = true
close(s.errorChan)
return err
}
func (s *server) closeWithError(e error) error {
s.mutex.Lock()
defer s.mutex.Unlock()
if s.closed {
return nil
}
s.serverError = e
return s.closeWithMutex()
}
// Addr returns the server's network address
func (s *server) Addr() net.Addr {
return s.conn.LocalAddr()
}
func (s *server) handlePacket(p *receivedPacket) {
hdr := p.hdr
// send a Version Negotiation Packet if the client is speaking a different protocol version
if !protocol.IsSupportedVersion(s.config.Versions, hdr.Version) {
go s.sendVersionNegotiationPacket(p)
return
}
if hdr.Type == protocol.PacketTypeInitial {
go s.handleInitial(p)
return
}
// TODO(#943): send Stateless Reset
p.buffer.Release()
}
func (s *server) handleInitial(p *receivedPacket) {
s.logger.Debugf("<- Received Initial packet.")
sess, connID, err := s.handleInitialImpl(p)
if err != nil {
p.buffer.Release()
s.logger.Errorf("Error occurred handling initial packet: %s", err)
return
}
if sess == nil { // a retry was done, or the connection attempt was rejected
p.buffer.Release()
return
}
// Don't put the packet buffer back if a new session was created.
// The session will handle the packet and take of that.
serverSession := newServerSession(sess, s.config, s.logger)
s.sessionHandler.Add(connID, serverSession)
}
func (s *server) handleInitialImpl(p *receivedPacket) (quicSession, protocol.ConnectionID, error) {
hdr := p.hdr
if len(hdr.Token) == 0 && hdr.DestConnectionID.Len() < protocol.MinConnectionIDLenInitial {
return nil, nil, errors.New("dropping Initial packet with too short connection ID")
}
if len(p.data) < protocol.MinInitialPacketSize {
return nil, nil, errors.New("dropping too small Initial packet")
}
var cookie *Cookie
var origDestConnectionID protocol.ConnectionID
if len(hdr.Token) > 0 {
c, err := s.cookieGenerator.DecodeToken(hdr.Token)
if err == nil {
cookie = &Cookie{
RemoteAddr: c.RemoteAddr,
SentTime: c.SentTime,
}
origDestConnectionID = c.OriginalDestConnectionID
}
}
if !s.config.AcceptCookie(p.remoteAddr, cookie) {
// Log the Initial packet now.
// If no Retry is sent, the packet will be logged by the session.
(&wire.ExtendedHeader{Header: *p.hdr}).Log(s.logger)
return nil, nil, s.sendRetry(p.remoteAddr, hdr)
}
if queueLen := atomic.LoadInt32(&s.sessionQueueLen); queueLen >= protocol.MaxAcceptQueueSize {
s.logger.Debugf("Rejecting new connection. Server currently busy. Accept queue length: %d (max %d)", queueLen, protocol.MaxAcceptQueueSize)
return nil, nil, s.sendServerBusy(p.remoteAddr, hdr)
}
connID, err := protocol.GenerateConnectionID(s.config.ConnectionIDLength)
if err != nil {
return nil, nil, err
}
s.logger.Debugf("Changing connection ID to %s.", connID)
sess, err := s.createNewSession(
p.remoteAddr,
origDestConnectionID,
hdr.DestConnectionID,
hdr.SrcConnectionID,
connID,
hdr.Version,
)
if err != nil {
return nil, nil, err
}
sess.handlePacket(p)
return sess, connID, nil
}
func (s *server) createNewSession(
remoteAddr net.Addr,
origDestConnID protocol.ConnectionID,
clientDestConnID protocol.ConnectionID,
destConnID protocol.ConnectionID,
srcConnID protocol.ConnectionID,
version protocol.VersionNumber,
) (quicSession, error) {
params := &handshake.TransportParameters{
InitialMaxStreamDataBidiLocal: protocol.InitialMaxStreamData,
InitialMaxStreamDataBidiRemote: protocol.InitialMaxStreamData,
InitialMaxStreamDataUni: protocol.InitialMaxStreamData,
InitialMaxData: protocol.InitialMaxData,
IdleTimeout: s.config.IdleTimeout,
MaxBidiStreams: uint64(s.config.MaxIncomingStreams),
MaxUniStreams: uint64(s.config.MaxIncomingUniStreams),
DisableMigration: true,
// TODO(#855): generate a real token
StatelessResetToken: bytes.Repeat([]byte{42}, 16),
OriginalConnectionID: origDestConnID,
}
sess, err := s.newSession(
&conn{pconn: s.conn, currentAddr: remoteAddr},
s.sessionRunner,
clientDestConnID,
destConnID,
srcConnID,
s.config,
s.tlsConf,
params,
s.logger,
version,
)
if err != nil {
return nil, err
}
go sess.run()
return sess, nil
}
func (s *server) sendRetry(remoteAddr net.Addr, hdr *wire.Header) error {
token, err := s.cookieGenerator.NewToken(remoteAddr, hdr.DestConnectionID)
if err != nil {
return err
}
connID, err := protocol.GenerateConnectionID(s.config.ConnectionIDLength)
if err != nil {
return err
}
replyHdr := &wire.ExtendedHeader{}
replyHdr.IsLongHeader = true
replyHdr.Type = protocol.PacketTypeRetry
replyHdr.Version = hdr.Version
replyHdr.SrcConnectionID = connID
replyHdr.DestConnectionID = hdr.SrcConnectionID
replyHdr.OrigDestConnectionID = hdr.DestConnectionID
replyHdr.Token = token
s.logger.Debugf("Changing connection ID to %s.\n-> Sending Retry", connID)
replyHdr.Log(s.logger)
buf := &bytes.Buffer{}
if err := replyHdr.Write(buf, hdr.Version); err != nil {
return err
}
if _, err := s.conn.WriteTo(buf.Bytes(), remoteAddr); err != nil {
s.logger.Debugf("Error sending Retry: %s", err)
}
return nil
}
func (s *server) sendServerBusy(remoteAddr net.Addr, hdr *wire.Header) error {
sealer, _, err := handshake.NewInitialAEAD(hdr.DestConnectionID, protocol.PerspectiveServer)
if err != nil {
return err
}
packetBuffer := getPacketBuffer()
defer packetBuffer.Release()
buf := bytes.NewBuffer(packetBuffer.Slice[:0])
// TODO(#1567): use the SERVER_BUSY error code
ccf := &wire.ConnectionCloseFrame{ErrorCode: qerr.PeerGoingAway}
replyHdr := &wire.ExtendedHeader{}
replyHdr.IsLongHeader = true
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())
if err := replyHdr.Write(buf, hdr.Version); err != nil {
return err
}
payloadOffset := buf.Len()
if err := ccf.Write(buf, hdr.Version); err != nil {
return err
}
raw := buf.Bytes()
_ = sealer.Seal(raw[payloadOffset:payloadOffset], raw[payloadOffset:], replyHdr.PacketNumber, raw[:payloadOffset])
raw = raw[0 : buf.Len()+sealer.Overhead()]
pnOffset := payloadOffset - int(replyHdr.PacketNumberLen)
sealer.EncryptHeader(
raw[pnOffset+4:pnOffset+4+16],
&raw[0],
raw[pnOffset:payloadOffset],
)
replyHdr.Log(s.logger)
wire.LogFrame(s.logger, ccf, true)
if _, err := s.conn.WriteTo(raw, remoteAddr); err != nil {
s.logger.Debugf("Error rejecting connection: %s", err)
}
return nil
}
func (s *server) sendVersionNegotiationPacket(p *receivedPacket) {
defer p.buffer.Release()
hdr := p.hdr
s.logger.Debugf("Client offered version %s, sending Version Negotiation", hdr.Version)
data, err := wire.ComposeVersionNegotiation(hdr.SrcConnectionID, hdr.DestConnectionID, s.config.Versions)
if err != nil {
s.logger.Debugf("Error composing Version Negotiation: %s", err)
return
}
if _, err := s.conn.WriteTo(data, p.remoteAddr); err != nil {
s.logger.Debugf("Error sending Version Negotiation: %s", err)
}
}