diff options
| -rw-r--r-- | pkg/tcpip/transport/tcp/accept.go | 25 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/endpoint.go | 4 |
2 files changed, 14 insertions, 15 deletions
diff --git a/pkg/tcpip/transport/tcp/accept.go b/pkg/tcpip/transport/tcp/accept.go index 3b574837c..0a2f3291c 100644 --- a/pkg/tcpip/transport/tcp/accept.go +++ b/pkg/tcpip/transport/tcp/accept.go @@ -20,6 +20,7 @@ import ( "fmt" "hash" "io" + "sync/atomic" "time" "gvisor.dev/gvisor/pkg/rand" @@ -390,7 +391,7 @@ func (l *listenContext) cleanupCompletedHandshake(h *handshake) { // deliverAccepted delivers the newly-accepted endpoint to the listener. If the // endpoint has transitioned out of the listen state (acceptedChan is nil), // the new endpoint is closed instead. -func (e *endpoint) deliverAccepted(n *endpoint) { +func (e *endpoint) deliverAccepted(n *endpoint, withSynCookie bool) { e.mu.Lock() e.pendingAccepted.Add(1) e.mu.Unlock() @@ -405,6 +406,9 @@ func (e *endpoint) deliverAccepted(n *endpoint) { } select { case e.acceptedChan <- n: + if !withSynCookie { + atomic.AddInt32(&e.synRcvdCount, -1) + } e.acceptMu.Unlock() e.waiterQueue.Notify(waiter.EventIn) return @@ -476,7 +480,7 @@ func (e *endpoint) handleSynSegment(ctx *listenContext, s *segment, opts *header if err != nil { e.stack.Stats().TCP.FailedConnectionAttempts.Increment() e.stats.FailedConnectionAttempts.Increment() - e.synRcvdCount-- + atomic.AddInt32(&e.synRcvdCount, -1) return err } @@ -486,18 +490,13 @@ func (e *endpoint) handleSynSegment(ctx *listenContext, s *segment, opts *header e.stack.Stats().TCP.FailedConnectionAttempts.Increment() e.stats.FailedConnectionAttempts.Increment() ctx.cleanupFailedHandshake(h) - e.mu.Lock() - e.synRcvdCount-- - e.mu.Unlock() + atomic.AddInt32(&e.synRcvdCount, -1) return } ctx.cleanupCompletedHandshake(h) - e.mu.Lock() - e.synRcvdCount-- - e.mu.Unlock() h.ep.startAcceptedLoop() e.stack.Stats().TCP.PassiveConnectionOpenings.Increment() - e.deliverAccepted(h.ep) + e.deliverAccepted(h.ep, false /*withSynCookie*/) }() // S/R-SAFE: synRcvdCount is the barrier. return nil @@ -505,17 +504,17 @@ func (e *endpoint) handleSynSegment(ctx *listenContext, s *segment, opts *header func (e *endpoint) incSynRcvdCount() bool { e.acceptMu.Lock() - canInc := e.synRcvdCount < cap(e.acceptedChan) + canInc := int(atomic.LoadInt32(&e.synRcvdCount)) < cap(e.acceptedChan) e.acceptMu.Unlock() if canInc { - e.synRcvdCount++ + atomic.AddInt32(&e.synRcvdCount, 1) } return canInc } func (e *endpoint) acceptQueueIsFull() bool { e.acceptMu.Lock() - full := len(e.acceptedChan)+e.synRcvdCount >= cap(e.acceptedChan) + full := len(e.acceptedChan)+int(atomic.LoadInt32(&e.synRcvdCount)) >= cap(e.acceptedChan) e.acceptMu.Unlock() return full } @@ -737,7 +736,7 @@ func (e *endpoint) handleListenSegment(ctx *listenContext, s *segment) tcpip.Err // Start the protocol goroutine. n.startAcceptedLoop() e.stack.Stats().TCP.PassiveConnectionOpenings.Increment() - go e.deliverAccepted(n) + go e.deliverAccepted(n, true /*withSynCookie*/) return nil default: diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go index 129f36d11..43d344350 100644 --- a/pkg/tcpip/transport/tcp/endpoint.go +++ b/pkg/tcpip/transport/tcp/endpoint.go @@ -532,8 +532,8 @@ type endpoint struct { segmentQueue segmentQueue `state:"wait"` // synRcvdCount is the number of connections for this endpoint that are - // in SYN-RCVD state. - synRcvdCount int + // in SYN-RCVD state; this is only accessed atomically. + synRcvdCount int32 // userMSS if non-zero is the MSS value explicitly set by the user // for this endpoint using the TCP_MAXSEG setsockopt. |