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authorgVisor bot <gvisor-bot@google.com>2021-03-16 22:13:06 +0000
committergVisor bot <gvisor-bot@google.com>2021-03-16 22:13:06 +0000
commit25ad40d9505a387348b33bf1a4b66e0f97cdb576 (patch)
tree7d1b6228d35085d88fad57bb3018a75483b6df47
parentc9a030e8e994b96c62822375b733d4db4e894c17 (diff)
parent5eede4e7563e245a685d6529dffddbf9c3a53f50 (diff)
Merge release-20210309.0-35-g5eede4e75 (automated)
-rw-r--r--pkg/tcpip/transport/tcp/accept.go25
-rw-r--r--pkg/tcpip/transport/tcp/endpoint.go4
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.