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packet_handler_map.go
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packet_handler_map.go
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package quic
import (
"crypto/hmac"
"crypto/rand"
"crypto/sha256"
"hash"
"io"
"net"
"sync"
"time"
"github.com/quic-go/quic-go/internal/protocol"
"github.com/quic-go/quic-go/internal/utils"
)
type connCapabilities struct {
// This connection has the Don't Fragment (DF) bit set.
// This means it makes to run DPLPMTUD.
DF bool
// GSO (Generic Segmentation Offload) supported
GSO bool
// ECN (Explicit Congestion Notifications) supported
ECN bool
}
// rawConn is a connection that allow reading of a receivedPackeh.
type rawConn interface {
ReadPacket() (receivedPacket, error)
// WritePacket writes a packet on the wire.
// gsoSize is the size of a single packet, or 0 to disable GSO.
// It is invalid to set gsoSize if capabilities.GSO is not set.
WritePacket(b []byte, addr net.Addr, packetInfoOOB []byte, gsoSize uint16, ecn protocol.ECN) (int, error)
LocalAddr() net.Addr
SetReadDeadline(time.Time) error
io.Closer
capabilities() connCapabilities
}
type closePacket struct {
payload []byte
addr net.Addr
info packetInfo
}
type packetHandlerMap struct {
mutex sync.Mutex
handlers map[protocol.ConnectionID]packetHandler
resetTokens map[protocol.StatelessResetToken] /* stateless reset token */ packetHandler
closed bool
closeChan chan struct{}
enqueueClosePacket func(closePacket)
deleteRetiredConnsAfter time.Duration
statelessResetMutex sync.Mutex
statelessResetHasher hash.Hash
logger utils.Logger
}
var _ packetHandlerManager = &packetHandlerMap{}
func newPacketHandlerMap(key *StatelessResetKey, enqueueClosePacket func(closePacket), logger utils.Logger) *packetHandlerMap {
h := &packetHandlerMap{
closeChan: make(chan struct{}),
handlers: make(map[protocol.ConnectionID]packetHandler),
resetTokens: make(map[protocol.StatelessResetToken]packetHandler),
deleteRetiredConnsAfter: protocol.RetiredConnectionIDDeleteTimeout,
enqueueClosePacket: enqueueClosePacket,
logger: logger,
}
if key != nil {
h.statelessResetHasher = hmac.New(sha256.New, key[:])
}
if h.logger.Debug() {
go h.logUsage()
}
return h
}
func (h *packetHandlerMap) logUsage() {
ticker := time.NewTicker(2 * time.Second)
var printedZero bool
for {
select {
case <-h.closeChan:
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) Get(id protocol.ConnectionID) (packetHandler, bool) {
h.mutex.Lock()
defer h.mutex.Unlock()
handler, ok := h.handlers[id]
return handler, ok
}
func (h *packetHandlerMap) Add(id protocol.ConnectionID, handler packetHandler) bool /* was added */ {
h.mutex.Lock()
defer h.mutex.Unlock()
if _, ok := h.handlers[id]; ok {
h.logger.Debugf("Not adding connection ID %s, as it already exists.", id)
return false
}
h.handlers[id] = handler
h.logger.Debugf("Adding connection ID %s.", id)
return true
}
func (h *packetHandlerMap) AddWithConnID(clientDestConnID, newConnID protocol.ConnectionID, fn func() (packetHandler, bool)) bool {
h.mutex.Lock()
defer h.mutex.Unlock()
if _, ok := h.handlers[clientDestConnID]; ok {
h.logger.Debugf("Not adding connection ID %s for a new connection, as it already exists.", clientDestConnID)
return false
}
conn, ok := fn()
if !ok {
return false
}
h.handlers[clientDestConnID] = conn
h.handlers[newConnID] = conn
h.logger.Debugf("Adding connection IDs %s and %s for a new connection.", clientDestConnID, newConnID)
return true
}
func (h *packetHandlerMap) Remove(id protocol.ConnectionID) {
h.mutex.Lock()
delete(h.handlers, 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.deleteRetiredConnsAfter)
time.AfterFunc(h.deleteRetiredConnsAfter, func() {
h.mutex.Lock()
delete(h.handlers, id)
h.mutex.Unlock()
h.logger.Debugf("Removing connection ID %s after it has been retired.", id)
})
}
// ReplaceWithClosed is called when a connection is closed.
// Depending on which side closed the connection, we need to:
// * remote close: absorb delayed packets
// * local close: retransmit the CONNECTION_CLOSE packet, in case it was lost
func (h *packetHandlerMap) ReplaceWithClosed(ids []protocol.ConnectionID, pers protocol.Perspective, connClosePacket []byte) {
var handler packetHandler
if connClosePacket != nil {
handler = newClosedLocalConn(
func(addr net.Addr, info packetInfo) {
h.enqueueClosePacket(closePacket{payload: connClosePacket, addr: addr, info: info})
},
pers,
h.logger,
)
} else {
handler = newClosedRemoteConn(pers)
}
h.mutex.Lock()
for _, id := range ids {
h.handlers[id] = handler
}
h.mutex.Unlock()
h.logger.Debugf("Replacing connection for connection IDs %s with a closed connection.", ids)
time.AfterFunc(h.deleteRetiredConnsAfter, func() {
h.mutex.Lock()
handler.shutdown()
for _, id := range ids {
delete(h.handlers, id)
}
h.mutex.Unlock()
h.logger.Debugf("Removing connection IDs %s for a closed connection after it has been retired.", ids)
})
}
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) GetByResetToken(token protocol.StatelessResetToken) (packetHandler, bool) {
h.mutex.Lock()
defer h.mutex.Unlock()
handler, ok := h.resetTokens[token]
return handler, ok
}
func (h *packetHandlerMap) CloseServer() {
h.mutex.Lock()
var wg sync.WaitGroup
for _, handler := range h.handlers {
if handler.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()
}(handler)
}
}
h.mutex.Unlock()
wg.Wait()
}
func (h *packetHandlerMap) Close(e error) {
h.mutex.Lock()
if h.closed {
h.mutex.Unlock()
return
}
close(h.closeChan)
var wg sync.WaitGroup
for _, handler := range h.handlers {
wg.Add(1)
go func(handler packetHandler) {
handler.destroy(e)
wg.Done()
}(handler)
}
h.closed = true
h.mutex.Unlock()
wg.Wait()
}
func (h *packetHandlerMap) GetStatelessResetToken(connID protocol.ConnectionID) protocol.StatelessResetToken {
var token protocol.StatelessResetToken
if h.statelessResetHasher == nil {
// 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
}