From 9ff1c425909ed1de53cbfd2755e98110001a3ed1 Mon Sep 17 00:00:00 2001
From: Kevin Krakauer <krakauer@google.com>
Date: Mon, 21 Nov 2022 13:54:57 -0800
Subject: [PATCH] gro: actually decref packets

Also improves performance since we're not leaking memory and allocating as
much.

PiperOrigin-RevId: 490064348
---
 pkg/tcpip/stack/gro.go | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/pkg/tcpip/stack/gro.go b/pkg/tcpip/stack/gro.go
index dd9be7589..78051c068 100644
--- a/pkg/tcpip/stack/gro.go
+++ b/pkg/tcpip/stack/gro.go
@@ -295,6 +295,7 @@ func (gd *groDispatcher) dispatch(pkt PacketBufferPtr, netProto tcpip.NetworkPro
 	if flushGROPkt {
 		// Flush the existing GRO packet.
 		ep.HandlePacket(groPkt.pkt)
+		groPkt.pkt.DecRef()
 		bucket.removeOne(groPkt)
 		groPkt = nil
 	} else if groPkt != nil {
@@ -325,6 +326,7 @@ func (gd *groDispatcher) dispatch(pkt PacketBufferPtr, netProto tcpip.NetworkPro
 	case flush && groPkt != nil:
 		// A merge occurred and we need to flush groPkt.
 		ep.HandlePacket(groPkt.pkt)
+		groPkt.pkt.DecRef()
 		bucket.removeOne(groPkt)
 	case flush && groPkt == nil:
 		// No merge occurred and the incoming packet needs to be flushed.
@@ -333,7 +335,9 @@ func (gd *groDispatcher) dispatch(pkt PacketBufferPtr, netProto tcpip.NetworkPro
 		// New flow and we don't need to flush. Insert pkt into GRO.
 		if bucket.full() {
 			// Head is always the oldest packet
-			ep.HandlePacket(bucket.removeOldest())
+			oldPkt := bucket.removeOldest()
+			ep.HandlePacket(oldPkt)
+			oldPkt.DecRef()
 		}
 		bucket.insert(pkt.IncRef(), ipHdr, tcpHdr, ep)
 	}
@@ -420,6 +424,7 @@ func (gd *groDispatcher) flush() {
 		for groPkt := bucket.packets.Front(); groPkt != nil; groPkt = groPkt.Next() {
 			if groPkt.created.Before(oldTime) {
 				groPkt.ep.HandlePacket(groPkt.pkt)
+				groPkt.pkt.DecRef()
 				bucket.removeOne(groPkt)
 			} else {
 				// Packets are ordered by age, so we can move
@@ -438,6 +443,7 @@ func (gd *groDispatcher) flushAll() {
 		bucket := &gd.buckets[i]
 		for groPkt := bucket.packets.Front(); groPkt != nil; groPkt = groPkt.Next() {
 			groPkt.ep.HandlePacket(groPkt.pkt)
+			groPkt.pkt.DecRef()
 			bucket.removeOne(groPkt)
 		}
 	}