cloudflared-mirror/vendor/github.com/lucas-clemente/quic-go/packet_handler_map.go

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package quic
import (
"crypto/hmac"
"crypto/rand"
"crypto/sha256"
"errors"
"fmt"
"hash"
"log"
"net"
"sync"
"time"
"github.com/lucas-clemente/quic-go/internal/protocol"
"github.com/lucas-clemente/quic-go/internal/utils"
"github.com/lucas-clemente/quic-go/internal/wire"
"github.com/lucas-clemente/quic-go/logging"
)
type statelessResetErr struct {
token protocol.StatelessResetToken
}
func (e statelessResetErr) Error() string {
return fmt.Sprintf("received a stateless reset with token %x", e.token)
}
type zeroRTTQueue struct {
queue []*receivedPacket
retireTimer *time.Timer
}
var _ packetHandler = &zeroRTTQueue{}
func (h *zeroRTTQueue) handlePacket(p *receivedPacket) {
if len(h.queue) < protocol.Max0RTTQueueLen {
h.queue = append(h.queue, p)
}
}
func (h *zeroRTTQueue) shutdown() {}
func (h *zeroRTTQueue) destroy(error) {}
func (h *zeroRTTQueue) getPerspective() protocol.Perspective { return protocol.PerspectiveClient }
func (h *zeroRTTQueue) EnqueueAll(sess packetHandler) {
for _, p := range h.queue {
sess.handlePacket(p)
}
}
func (h *zeroRTTQueue) Clear() {
for _, p := range h.queue {
p.buffer.Release()
}
}
type packetHandlerMapEntry struct {
packetHandler packetHandler
is0RTTQueue bool
}
// The packetHandlerMap stores packetHandlers, identified by connection ID.
// It is used:
// * by the server to store sessions
// * when multiplexing outgoing connections to store clients
type packetHandlerMap struct {
mutex sync.Mutex
conn connection
connIDLen int
handlers map[string] /* string(ConnectionID)*/ packetHandlerMapEntry
resetTokens map[protocol.StatelessResetToken] /* stateless reset token */ packetHandler
server unknownPacketHandler
numZeroRTTEntries int
listening chan struct{} // is closed when listen returns
closed bool
deleteRetiredSessionsAfter time.Duration
zeroRTTQueueDuration time.Duration
statelessResetEnabled bool
statelessResetMutex sync.Mutex
statelessResetHasher hash.Hash
tracer logging.Tracer
logger utils.Logger
}
var _ packetHandlerManager = &packetHandlerMap{}
func setReceiveBuffer(c net.PacketConn, logger utils.Logger) error {
conn, ok := c.(interface{ SetReadBuffer(int) error })
if !ok {
return errors.New("connection doesn't allow setting of receive buffer size. Not a *net.UDPConn?")
}
size, err := inspectReadBuffer(c)
if err != nil {
return fmt.Errorf("failed to determine receive buffer size: %w", err)
}
if size >= protocol.DesiredReceiveBufferSize {
logger.Debugf("Conn has receive buffer of %d kiB (wanted: at least %d kiB)", size/1024, protocol.DesiredReceiveBufferSize/1024)
}
if err := conn.SetReadBuffer(protocol.DesiredReceiveBufferSize); err != nil {
return fmt.Errorf("failed to increase receive buffer size: %w", err)
}
newSize, err := inspectReadBuffer(c)
if err != nil {
return fmt.Errorf("failed to determine receive buffer size: %w", err)
}
if newSize == size {
return fmt.Errorf("failed to increase receive buffer size (wanted: %d kiB, got %d kiB)", protocol.DesiredReceiveBufferSize/1024, newSize/1024)
}
if newSize < protocol.DesiredReceiveBufferSize {
return fmt.Errorf("failed to sufficiently increase receive buffer size (was: %d kiB, wanted: %d kiB, got: %d kiB)", size/1024, protocol.DesiredReceiveBufferSize/1024, newSize/1024)
}
logger.Debugf("Increased receive buffer size to %d kiB", newSize/1024)
return nil
}
// only print warnings about the UPD receive buffer size once
var receiveBufferWarningOnce sync.Once
func newPacketHandlerMap(
c net.PacketConn,
connIDLen int,
statelessResetKey []byte,
tracer logging.Tracer,
logger utils.Logger,
) (packetHandlerManager, error) {
if err := setReceiveBuffer(c, logger); err != nil {
receiveBufferWarningOnce.Do(func() {
log.Printf("%s. See https://github.com/lucas-clemente/quic-go/wiki/UDP-Receive-Buffer-Size for details.", err)
})
}
conn, err := wrapConn(c)
if err != nil {
return nil, err
}
m := &packetHandlerMap{
conn: conn,
connIDLen: connIDLen,
listening: make(chan struct{}),
handlers: make(map[string]packetHandlerMapEntry),
resetTokens: make(map[protocol.StatelessResetToken]packetHandler),
deleteRetiredSessionsAfter: protocol.RetiredConnectionIDDeleteTimeout,
zeroRTTQueueDuration: protocol.Max0RTTQueueingDuration,
statelessResetEnabled: len(statelessResetKey) > 0,
statelessResetHasher: hmac.New(sha256.New, statelessResetKey),
tracer: tracer,
logger: logger,
}
go m.listen()
if logger.Debug() {
go m.logUsage()
}
return m, nil
}
func (h *packetHandlerMap) logUsage() {
ticker := time.NewTicker(2 * time.Second)
var printedZero bool
for {
select {
case <-h.listening:
return
case <-ticker.C:
}
h.mutex.Lock()
numHandlers := len(h.handlers)
numTokens := len(h.resetTokens)
h.mutex.Unlock()
// If the number tracked handlers and tokens is zero, only print it a single time.
hasZero := numHandlers == 0 && numTokens == 0
if !hasZero || (hasZero && !printedZero) {
h.logger.Debugf("Tracking %d connection IDs and %d reset tokens.\n", numHandlers, numTokens)
printedZero = false
if hasZero {
printedZero = true
}
}
}
}
func (h *packetHandlerMap) Add(id protocol.ConnectionID, handler packetHandler) bool /* was added */ {
h.mutex.Lock()
defer h.mutex.Unlock()
if _, ok := h.handlers[string(id)]; ok {
h.logger.Debugf("Not adding connection ID %s, as it already exists.", id)
return false
}
h.handlers[string(id)] = packetHandlerMapEntry{packetHandler: handler}
h.logger.Debugf("Adding connection ID %s.", id)
return true
}
func (h *packetHandlerMap) AddWithConnID(clientDestConnID, newConnID protocol.ConnectionID, fn func() packetHandler) bool {
h.mutex.Lock()
defer h.mutex.Unlock()
var q *zeroRTTQueue
if entry, ok := h.handlers[string(clientDestConnID)]; ok {
if !entry.is0RTTQueue {
h.logger.Debugf("Not adding connection ID %s for a new session, as it already exists.", clientDestConnID)
return false
}
q = entry.packetHandler.(*zeroRTTQueue)
q.retireTimer.Stop()
h.numZeroRTTEntries--
if h.numZeroRTTEntries < 0 {
panic("number of 0-RTT queues < 0")
}
}
sess := fn()
if q != nil {
q.EnqueueAll(sess)
}
h.handlers[string(clientDestConnID)] = packetHandlerMapEntry{packetHandler: sess}
h.handlers[string(newConnID)] = packetHandlerMapEntry{packetHandler: sess}
h.logger.Debugf("Adding connection IDs %s and %s for a new session.", clientDestConnID, newConnID)
return true
}
func (h *packetHandlerMap) Remove(id protocol.ConnectionID) {
h.mutex.Lock()
delete(h.handlers, string(id))
h.mutex.Unlock()
h.logger.Debugf("Removing connection ID %s.", id)
}
func (h *packetHandlerMap) Retire(id protocol.ConnectionID) {
h.logger.Debugf("Retiring connection ID %s in %s.", id, h.deleteRetiredSessionsAfter)
time.AfterFunc(h.deleteRetiredSessionsAfter, func() {
h.mutex.Lock()
delete(h.handlers, string(id))
h.mutex.Unlock()
h.logger.Debugf("Removing connection ID %s after it has been retired.", id)
})
}
func (h *packetHandlerMap) ReplaceWithClosed(id protocol.ConnectionID, handler packetHandler) {
h.mutex.Lock()
h.handlers[string(id)] = packetHandlerMapEntry{packetHandler: handler}
h.mutex.Unlock()
h.logger.Debugf("Replacing session for connection ID %s with a closed session.", id)
time.AfterFunc(h.deleteRetiredSessionsAfter, func() {
h.mutex.Lock()
handler.shutdown()
delete(h.handlers, string(id))
h.mutex.Unlock()
h.logger.Debugf("Removing connection ID %s for a closed session after it has been retired.", id)
})
}
func (h *packetHandlerMap) AddResetToken(token protocol.StatelessResetToken, handler packetHandler) {
h.mutex.Lock()
h.resetTokens[token] = handler
h.mutex.Unlock()
}
func (h *packetHandlerMap) RemoveResetToken(token protocol.StatelessResetToken) {
h.mutex.Lock()
delete(h.resetTokens, token)
h.mutex.Unlock()
}
func (h *packetHandlerMap) SetServer(s unknownPacketHandler) {
h.mutex.Lock()
h.server = s
h.mutex.Unlock()
}
func (h *packetHandlerMap) CloseServer() {
h.mutex.Lock()
if h.server == nil {
h.mutex.Unlock()
return
}
h.server = nil
var wg sync.WaitGroup
for _, entry := range h.handlers {
if entry.packetHandler.getPerspective() == protocol.PerspectiveServer {
wg.Add(1)
go func(handler packetHandler) {
// blocks until the CONNECTION_CLOSE has been sent and the run-loop has stopped
handler.shutdown()
wg.Done()
}(entry.packetHandler)
}
}
h.mutex.Unlock()
wg.Wait()
}
// Destroy closes the underlying connection and waits until listen() has returned.
// It does not close active sessions.
func (h *packetHandlerMap) Destroy() error {
if err := h.conn.Close(); err != nil {
return err
}
<-h.listening // wait until listening returns
return nil
}
func (h *packetHandlerMap) close(e error) error {
h.mutex.Lock()
if h.closed {
h.mutex.Unlock()
return nil
}
var wg sync.WaitGroup
for _, entry := range h.handlers {
wg.Add(1)
go func(handler packetHandler) {
handler.destroy(e)
wg.Done()
}(entry.packetHandler)
}
if h.server != nil {
h.server.setCloseError(e)
}
h.closed = true
h.mutex.Unlock()
wg.Wait()
return getMultiplexer().RemoveConn(h.conn)
}
func (h *packetHandlerMap) listen() {
defer close(h.listening)
for {
p, err := h.conn.ReadPacket()
if nerr, ok := err.(net.Error); ok && nerr.Temporary() {
h.logger.Debugf("Temporary error reading from conn: %w", err)
continue
}
if err != nil {
h.close(err)
return
}
h.handlePacket(p)
}
}
func (h *packetHandlerMap) handlePacket(p *receivedPacket) {
connID, err := wire.ParseConnectionID(p.data, h.connIDLen)
if err != nil {
h.logger.Debugf("error parsing connection ID on packet from %s: %s", p.remoteAddr, err)
if h.tracer != nil {
h.tracer.DroppedPacket(p.remoteAddr, logging.PacketTypeNotDetermined, p.Size(), logging.PacketDropHeaderParseError)
}
p.buffer.MaybeRelease()
return
}
h.mutex.Lock()
defer h.mutex.Unlock()
if isStatelessReset := h.maybeHandleStatelessReset(p.data); isStatelessReset {
return
}
if entry, ok := h.handlers[string(connID)]; ok {
if entry.is0RTTQueue { // only enqueue 0-RTT packets in the 0-RTT queue
if wire.Is0RTTPacket(p.data) {
entry.packetHandler.handlePacket(p)
return
}
} else { // existing session
entry.packetHandler.handlePacket(p)
return
}
}
if p.data[0]&0x80 == 0 {
go h.maybeSendStatelessReset(p, connID)
return
}
if h.server == nil { // no server set
h.logger.Debugf("received a packet with an unexpected connection ID %s", connID)
return
}
if wire.Is0RTTPacket(p.data) {
if h.numZeroRTTEntries >= protocol.Max0RTTQueues {
return
}
h.numZeroRTTEntries++
queue := &zeroRTTQueue{queue: make([]*receivedPacket, 0, 8)}
h.handlers[string(connID)] = packetHandlerMapEntry{
packetHandler: queue,
is0RTTQueue: true,
}
queue.retireTimer = time.AfterFunc(h.zeroRTTQueueDuration, func() {
h.mutex.Lock()
defer h.mutex.Unlock()
// The entry might have been replaced by an actual session.
// Only delete it if it's still a 0-RTT queue.
if entry, ok := h.handlers[string(connID)]; ok && entry.is0RTTQueue {
delete(h.handlers, string(connID))
h.numZeroRTTEntries--
if h.numZeroRTTEntries < 0 {
panic("number of 0-RTT queues < 0")
}
entry.packetHandler.(*zeroRTTQueue).Clear()
if h.logger.Debug() {
h.logger.Debugf("Removing 0-RTT queue for %s.", connID)
}
}
})
queue.handlePacket(p)
return
}
h.server.handlePacket(p)
}
func (h *packetHandlerMap) maybeHandleStatelessReset(data []byte) bool {
// stateless resets are always short header packets
if data[0]&0x80 != 0 {
return false
}
if len(data) < 17 /* type byte + 16 bytes for the reset token */ {
return false
}
var token protocol.StatelessResetToken
copy(token[:], data[len(data)-16:])
if sess, ok := h.resetTokens[token]; ok {
h.logger.Debugf("Received a stateless reset with token %#x. Closing session.", token)
go sess.destroy(statelessResetErr{token: token})
return true
}
return false
}
func (h *packetHandlerMap) GetStatelessResetToken(connID protocol.ConnectionID) protocol.StatelessResetToken {
var token protocol.StatelessResetToken
if !h.statelessResetEnabled {
// Return a random stateless reset token.
// This token will be sent in the server's transport parameters.
// By using a random token, an off-path attacker won't be able to disrupt the connection.
rand.Read(token[:])
return token
}
h.statelessResetMutex.Lock()
h.statelessResetHasher.Write(connID.Bytes())
copy(token[:], h.statelessResetHasher.Sum(nil))
h.statelessResetHasher.Reset()
h.statelessResetMutex.Unlock()
return token
}
func (h *packetHandlerMap) maybeSendStatelessReset(p *receivedPacket, connID protocol.ConnectionID) {
defer p.buffer.Release()
if !h.statelessResetEnabled {
return
}
// Don't send a stateless reset in response to very small packets.
// This includes packets that could be stateless resets.
if len(p.data) <= protocol.MinStatelessResetSize {
return
}
token := h.GetStatelessResetToken(connID)
h.logger.Debugf("Sending stateless reset to %s (connection ID: %s). Token: %#x", p.remoteAddr, connID, token)
data := make([]byte, protocol.MinStatelessResetSize-16, protocol.MinStatelessResetSize)
rand.Read(data)
data[0] = (data[0] & 0x7f) | 0x40
data = append(data, token[:]...)
if _, err := h.conn.WritePacket(data, p.remoteAddr, p.info.OOB()); err != nil {
h.logger.Debugf("Error sending Stateless Reset: %s", err)
}
}