Add reference counting to packet buffers.

PiperOrigin-RevId: 408426639

9 files changed, 23 insertions, 2 deletions

diff --git a/pkg/tcpip/network/arp/arp.go b/pkg/tcpip/network/arp/arp.go
index e08243547..8e6be7e26 100644
--- a/pkg/tcpip/network/arp/arp.go
+++ b/pkg/tcpip/network/arp/arp.go
@@ -198,6 +198,7 @@ func (e *endpoint) HandlePacket(pkt *stack.PacketBuffer) {
 		respPkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
 			ReserveHeaderBytes: int(e.nic.MaxHeaderLength()) + header.ARPSize,
 		})
+		defer respPkt.DecRef()
 		packet := header.ARP(respPkt.NetworkHeader().Push(header.ARPSize))
 		respPkt.NetworkProtocolNumber = ProtocolNumber
 		packet.SetIPv4OverEthernet()
@@ -339,6 +340,7 @@ func (e *endpoint) sendARPRequest(localAddr, targetAddr tcpip.Address, remoteLin
 	pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
 		ReserveHeaderBytes: int(e.MaxHeaderLength()),
 	})
+	defer pkt.DecRef()
 	h := header.ARP(pkt.NetworkHeader().Push(header.ARPSize))
 	pkt.NetworkProtocolNumber = ProtocolNumber
 	h.SetIPv4OverEthernet()
diff --git a/pkg/tcpip/network/internal/fragmentation/reassembler.go b/pkg/tcpip/network/internal/fragmentation/reassembler.go
index 5b7e4b361..ff6be8f0d 100644
--- a/pkg/tcpip/network/internal/fragmentation/reassembler.go
+++ b/pkg/tcpip/network/internal/fragmentation/reassembler.go
@@ -149,6 +149,7 @@ func (r *reassembler) process(first, last uint16, more bool, proto uint8, pkt *s
 			r.proto = proto
 		}
 
+		pkt.IncRef()
 		break
 	}
 	if !holeFound {
@@ -166,6 +167,7 @@ func (r *reassembler) process(first, last uint16, more bool, proto uint8, pkt *s
 	})
 
 	resPkt := r.holes[0].pkt
+	resPkt.DecRef()
 	for i := 1; i < len(r.holes); i++ {
 		stack.MergeFragment(resPkt, r.holes[i].pkt)
 	}
diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go
index 59acbad02..33a1b837e 100644
--- a/pkg/tcpip/network/ipv4/icmp.go
+++ b/pkg/tcpip/network/ipv4/icmp.go
@@ -239,7 +239,7 @@ func (e *endpoint) handleICMP(pkt *stack.PacketBuffer) {
 	case header.ICMPv4Echo:
 		received.echoRequest.Increment()
 
-		// DeliverTransportPacket will take ownership of pkt so don't use it beyond
+		// DeliverTransportPacket may modify pkt so don't use it beyond
 		// this point. Make a deep copy of the data before pkt gets sent as we will
 		// be modifying fields. Both the ICMP header (with its type modified to
 		// EchoReply) and payload are reused in the reply packet.
@@ -320,6 +320,7 @@ func (e *endpoint) handleICMP(pkt *stack.PacketBuffer) {
 			ReserveHeaderBytes: int(r.MaxHeaderLength()),
 			Data:               replyVV,
 		})
+		defer replyPkt.DecRef()
 		replyPkt.TransportProtocolNumber = header.ICMPv4ProtocolNumber
 
 		if err := r.WriteHeaderIncludedPacket(replyPkt); err != nil {
@@ -667,6 +668,7 @@ func (p *protocol) returnError(reason icmpReason, pkt *stack.PacketBuffer) tcpip
 		ReserveHeaderBytes: int(route.MaxHeaderLength()) + header.ICMPv4MinimumSize,
 		Data:               payload,
 	})
+	defer icmpPkt.DecRef()
 
 	icmpPkt.TransportProtocolNumber = header.ICMPv4ProtocolNumber
 
diff --git a/pkg/tcpip/network/ipv4/igmp.go b/pkg/tcpip/network/ipv4/igmp.go
index 3ce499298..d9cc4574e 100644
--- a/pkg/tcpip/network/ipv4/igmp.go
+++ b/pkg/tcpip/network/ipv4/igmp.go
@@ -322,6 +322,7 @@ func (igmp *igmpState) writePacket(destAddress tcpip.Address, groupAddress tcpip
 		ReserveHeaderBytes: int(igmp.ep.MaxHeaderLength()),
 		Data:               buffer.View(igmpData).ToVectorisedView(),
 	})
+	defer pkt.DecRef()
 
 	addressEndpoint := igmp.ep.acquireOutgoingPrimaryAddressRLocked(destAddress, false /* allowExpired */)
 	if addressEndpoint == nil {
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go
index d1d509702..e55f5eea6 100644
--- a/pkg/tcpip/network/ipv4/ipv4.go
+++ b/pkg/tcpip/network/ipv4/ipv4.go
@@ -119,6 +119,7 @@ func (e *endpoint) HandleLinkResolutionFailure(pkt *stack.PacketBuffer) {
 	pkt = stack.NewPacketBuffer(stack.PacketBufferOptions{
 		Data: buffer.NewVectorisedView(pkt.Size(), pkt.Views()),
 	})
+	defer pkt.DecRef()
 	pkt.NICID = e.nic.ID()
 	pkt.NetworkProtocolNumber = ProtocolNumber
 	// Use the same control type as an ICMPv4 destination host unreachable error
@@ -534,6 +535,7 @@ func (e *endpoint) WritePackets(r *stack.Route, pkts stack.PacketBufferList, par
 			// removed once the fragmentation is done.
 			originalPkt := pkt
 			if _, _, err := e.handleFragments(r, networkMTU, pkt, func(fragPkt *stack.PacketBuffer) tcpip.Error {
+				fragPkt.IncRef()
 				// Modify the packet list in place with the new fragments.
 				pkts.InsertAfter(pkt, fragPkt)
 				pkt = fragPkt
@@ -751,10 +753,11 @@ func (e *endpoint) forwardPacket(pkt *stack.PacketBuffer) ip.ForwardingError {
 	}
 
 	// We need to do a deep copy of the IP packet because
-	// WriteHeaderIncludedPacket takes ownership of the packet buffer, but we do
+	// WriteHeaderIncludedPacket may modify the packet buffer, but we do
 	// not own it.
 	newPkt := pkt.DeepCopyForForwarding(int(r.MaxHeaderLength()))
 	newHdr := header.IPv4(newPkt.NetworkHeader().View())
+	defer newPkt.DecRef()
 
 	// As per RFC 791 page 30, Time to Live,
 	//
@@ -859,6 +862,7 @@ func (e *endpoint) handleLocalPacket(pkt *stack.PacketBuffer, canSkipRXChecksum
 	stats.PacketsReceived.Increment()
 
 	pkt = pkt.CloneToInbound()
+	defer pkt.DecRef()
 	pkt.RXTransportChecksumValidated = canSkipRXChecksum
 
 	h, ok := e.protocol.parseAndValidate(pkt)
diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go
index adfc8d8da..402c4c8a8 100644
--- a/pkg/tcpip/network/ipv6/icmp.go
+++ b/pkg/tcpip/network/ipv6/icmp.go
@@ -525,6 +525,7 @@ func (e *endpoint) handleICMP(pkt *stack.PacketBuffer, hasFragmentHeader bool, r
 		pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
 			ReserveHeaderBytes: int(r.MaxHeaderLength()) + neighborAdvertSize,
 		})
+		defer pkt.DecRef()
 		pkt.TransportProtocolNumber = header.ICMPv6ProtocolNumber
 		packet := header.ICMPv6(pkt.TransportHeader().Push(neighborAdvertSize))
 		packet.SetType(header.ICMPv6NeighborAdvert)
@@ -675,6 +676,7 @@ func (e *endpoint) handleICMP(pkt *stack.PacketBuffer, hasFragmentHeader bool, r
 			ReserveHeaderBytes: int(r.MaxHeaderLength()) + header.ICMPv6EchoMinimumSize,
 			Data:               pkt.Data().ExtractVV(),
 		})
+		defer replyPkt.DecRef()
 		icmp := header.ICMPv6(replyPkt.TransportHeader().Push(header.ICMPv6EchoMinimumSize))
 		pkt.TransportProtocolNumber = header.ICMPv6ProtocolNumber
 		copy(icmp, h)
@@ -1213,6 +1215,7 @@ func (p *protocol) returnError(reason icmpReason, pkt *stack.PacketBuffer) tcpip
 		ReserveHeaderBytes: int(route.MaxHeaderLength()) + header.ICMPv6ErrorHeaderSize,
 		Data:               payload,
 	})
+	defer newPkt.DecRef()
 	newPkt.TransportProtocolNumber = header.ICMPv6ProtocolNumber
 
 	icmpHdr := header.ICMPv6(newPkt.TransportHeader().Push(header.ICMPv6DstUnreachableMinimumSize))
diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go
index 7d3e1fd53..0c8ff6fb9 100644
--- a/pkg/tcpip/network/ipv6/ipv6.go
+++ b/pkg/tcpip/network/ipv6/ipv6.go
@@ -296,6 +296,7 @@ func (e *endpoint) HandleLinkResolutionFailure(pkt *stack.PacketBuffer) {
 	pkt = stack.NewPacketBuffer(stack.PacketBufferOptions{
 		Data: buffer.NewVectorisedView(pkt.Size(), pkt.Views()),
 	})
+	defer pkt.DecRef()
 	pkt.NICID = e.nic.ID()
 	pkt.NetworkProtocolNumber = ProtocolNumber
 	e.handleControl(&icmpv6DestinationAddressUnreachableSockError{}, pkt)
@@ -855,6 +856,7 @@ func (e *endpoint) WritePackets(r *stack.Route, pkts stack.PacketBufferList, par
 			// removed once the fragmentation is done.
 			originalPkt := pb
 			if _, _, err := e.handleFragments(r, networkMTU, pb, params.Protocol, func(fragPkt *stack.PacketBuffer) tcpip.Error {
+				fragPkt.IncRef()
 				// Modify the packet list in place with the new fragments.
 				pkts.InsertAfter(pb, fragPkt)
 				pb = fragPkt
@@ -1025,6 +1027,7 @@ func (e *endpoint) forwardPacket(pkt *stack.PacketBuffer) ip.ForwardingError {
 	// WriteHeaderIncludedPacket takes ownership of the packet buffer, but we do
 	// not own it.
 	newPkt := pkt.DeepCopyForForwarding(int(r.MaxHeaderLength()))
+	defer newPkt.DecRef()
 	newHdr := header.IPv6(newPkt.NetworkHeader().View())
 
 	// As per RFC 8200 section 3,
@@ -1118,6 +1121,7 @@ func (e *endpoint) handleLocalPacket(pkt *stack.PacketBuffer, canSkipRXChecksum
 	stats.PacketsReceived.Increment()
 
 	pkt = pkt.CloneToInbound()
+	defer pkt.DecRef()
 	pkt.RXTransportChecksumValidated = canSkipRXChecksum
 
 	h, ok := e.protocol.parseAndValidate(pkt)
diff --git a/pkg/tcpip/network/ipv6/mld.go b/pkg/tcpip/network/ipv6/mld.go
index bc1af193c..06a8e1b89 100644
--- a/pkg/tcpip/network/ipv6/mld.go
+++ b/pkg/tcpip/network/ipv6/mld.go
@@ -270,6 +270,7 @@ func (mld *mldState) writePacket(destAddress, groupAddress tcpip.Address, mldTyp
 		ReserveHeaderBytes: int(mld.ep.MaxHeaderLength()) + extensionHeaders.Length(),
 		Data:               buffer.View(icmp).ToVectorisedView(),
 	})
+	defer pkt.DecRef()
 
 	if err := addIPHeader(localAddress, destAddress, pkt, stack.NetworkHeaderParams{
 		Protocol: header.ICMPv6ProtocolNumber,
diff --git a/pkg/tcpip/network/ipv6/ndp.go b/pkg/tcpip/network/ipv6/ndp.go
index 938427420..bebf72421 100644
--- a/pkg/tcpip/network/ipv6/ndp.go
+++ b/pkg/tcpip/network/ipv6/ndp.go
@@ -1807,6 +1807,7 @@ func (ndp *ndpState) startSolicitingRouters() {
 				ReserveHeaderBytes: int(ndp.ep.MaxHeaderLength()),
 				Data:               buffer.View(icmpData).ToVectorisedView(),
 			})
+			defer pkt.DecRef()
 
 			sent := ndp.ep.stats.icmp.packetsSent
 			if err := addIPHeader(localAddr, header.IPv6AllRoutersLinkLocalMulticastAddress, pkt, stack.NetworkHeaderParams{
@@ -1924,6 +1925,7 @@ func (e *endpoint) sendNDPNS(srcAddr, dstAddr, targetAddr tcpip.Address, remoteL
 		ReserveHeaderBytes: int(e.MaxHeaderLength()),
 		Data:               buffer.View(icmp).ToVectorisedView(),
 	})
+	defer pkt.DecRef()
 
 	if err := addIPHeader(srcAddr, dstAddr, pkt, stack.NetworkHeaderParams{
 		Protocol: header.ICMPv6ProtocolNumber,