netstack: remove PacketBuffer.IsNil()

The change was originally motivated by ticket references (cl/450976957), which were never implemented. PiperOrigin-RevId: 617480960
google · Mar 20, 2024 · 3c75945 · 3c75945
1 parent 5a6aadd
commit 3c75945
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Showing 40 changed files with 208 additions and 213 deletions.
diff --git a/pkg/tcpip/link/channel/channel.go b/pkg/tcpip/link/channel/channel.go
@@ -180,7 +180,7 @@ func (e *Endpoint) ReadContext(ctx context.Context) *stack.PacketBuffer {
 // Drain removes all outbound packets from the channel and counts them.
 func (e *Endpoint) Drain() int {
 	c := 0
-	for pkt := e.Read(); !pkt.IsNil(); pkt = e.Read() {
+	for pkt := e.Read(); pkt != nil; pkt = e.Read() {
 		pkt.DecRef()
 		c++
 	}

diff --git a/pkg/tcpip/link/ethernet/ethernet_test.go b/pkg/tcpip/link/ethernet/ethernet_test.go
@@ -193,7 +193,7 @@ func TestWritePacketToRemoteAddHeader(t *testing.T) {
 
 	{
 		pkt := c.Read()
-		if pkt.IsNil() {
+		if pkt == nil {
 			t.Fatal("expected to read a packet")
 		}
 

diff --git a/pkg/tcpip/link/fdbased/endpoint_test.go b/pkg/tcpip/link/fdbased/endpoint_test.go
@@ -62,7 +62,7 @@ func checkPacketInfoEqual(t *testing.T, got, want packetInfo) {
 	if diff := cmp.Diff(
 		want, got,
 		cmp.Transformer("ExtractPacketBuffer", func(pk *stack.PacketBuffer) *packetContents {
-			if pk.IsNil() {
+			if pk == nil {
 				return nil
 			}
 			return &packetContents{

diff --git a/pkg/tcpip/link/packetsocket/packetsocket_test.go b/pkg/tcpip/link/packetsocket/packetsocket_test.go
@@ -76,10 +76,10 @@ type testNetworkDispatcher struct {
 }
 
 func (t *testNetworkDispatcher) reset() {
-	if pkt := t.linkPacket.pkt; !pkt.IsNil() {
+	if pkt := t.linkPacket.pkt; pkt != nil {
 		pkt.DecRef()
 	}
-	if pkt := t.networkPacket.pkt; !pkt.IsNil() {
+	if pkt := t.networkPacket.pkt; pkt != nil {
 		pkt.DecRef()
 	}
 

diff --git a/pkg/tcpip/link/qdisc/fifo/fifo.go b/pkg/tcpip/link/qdisc/fifo/fifo.go
@@ -97,7 +97,7 @@ func (qd *queueDispatcher) dispatchLoop() {
 		case &qd.newPacketWaker:
 		case &qd.closeWaker:
 			qd.mu.Lock()
-			for p := qd.queue.removeFront(); !p.IsNil(); p = qd.queue.removeFront() {
+			for p := qd.queue.removeFront(); p != nil; p = qd.queue.removeFront() {
 				p.DecRef()
 			}
 			qd.queue.decRef()
@@ -107,7 +107,7 @@ func (qd *queueDispatcher) dispatchLoop() {
 			panic("unknown waker")
 		}
 		qd.mu.Lock()
-		for pkt := qd.queue.removeFront(); !pkt.IsNil(); pkt = qd.queue.removeFront() {
+		for pkt := qd.queue.removeFront(); pkt != nil; pkt = qd.queue.removeFront() {
 			batch.PushBack(pkt)
 			if batch.Len() < BatchSize && !qd.queue.isEmpty() {
 				continue

diff --git a/pkg/tcpip/link/tun/device.go b/pkg/tcpip/link/tun/device.go
@@ -262,7 +262,7 @@ func (d *Device) Read() (*buffer.View, error) {
 	}
 
 	pkt := endpoint.Read()
-	if pkt.IsNil() {
+	if pkt == nil {
 		return nil, linuxerr.ErrWouldBlock
 	}
 	v := d.encodePkt(pkt)

diff --git a/pkg/tcpip/network/arp/arp_test.go b/pkg/tcpip/network/arp/arp_test.go
@@ -319,7 +319,7 @@ func TestDirectRequest(t *testing.T) {
 				// No packets should be sent after receiving an invalid ARP request.
 				// There is no need to perform a blocking read here, since packets are
 				// sent in the same function that handles ARP requests.
-				if pkt := c.linkEP.Read(); !pkt.IsNil() {
+				if pkt := c.linkEP.Read(); pkt != nil {
 					t.Errorf("unexpected packet sent: %+v", pkt)
 				}
 				if got, want := c.s.Stats().ARP.RequestsReceivedUnknownTargetAddress.Value(), requestsRecvUnknownAddr+1; got != want {
@@ -338,7 +338,7 @@ func TestDirectRequest(t *testing.T) {
 
 			// Verify an ARP response was sent.
 			pi := c.linkEP.Read()
-			if pi.IsNil() {
+			if pi == nil {
 				t.Fatal("expected ARP response to be sent, got none")
 			}
 
@@ -714,7 +714,7 @@ func TestLinkAddressRequest(t *testing.T) {
 			}
 
 			pkt := linkEP.Read()
-			if pkt.IsNil() {
+			if pkt == nil {
 				t.Fatal("expected to send a link address request")
 			}
 
@@ -773,7 +773,7 @@ func TestDADARPRequestPacket(t *testing.T) {
 
 	clock.RunImmediatelyScheduledJobs()
 	pkt := e.Read()
-	if pkt.IsNil() {
+	if pkt == nil {
 		t.Fatal("expected to send an ARP request")
 	}
 

diff --git a/pkg/tcpip/network/internal/fragmentation/fragmentation.go b/pkg/tcpip/network/internal/fragmentation/fragmentation.go
@@ -251,12 +251,12 @@ func (f *Fragmentation) release(r *reassembler, timedOut bool) {
 	if h := f.timeoutHandler; timedOut && h != nil {
 		h.OnReassemblyTimeout(r.pkt)
 	}
-	if !r.pkt.IsNil() {
+	if r.pkt != nil {
 		r.pkt.DecRef()
 		r.pkt = nil
 	}
 	for _, h := range r.holes {
-		if !h.pkt.IsNil() {
+		if h.pkt != nil {
 			h.pkt.DecRef()
 			h.pkt = nil
 		}

diff --git a/pkg/tcpip/network/internal/fragmentation/fragmentation_test.go b/pkg/tcpip/network/internal/fragmentation/fragmentation_test.go
@@ -117,7 +117,7 @@ func TestFragmentationProcess(t *testing.T) {
 				defer in.pkt.DecRef()
 				defer c.out[i].buf.Release()
 				resPkt, proto, done, err := f.Process(in.id, in.first, in.last, in.more, in.proto, in.pkt)
-				if !resPkt.IsNil() {
+				if resPkt != nil {
 					defer resPkt.DecRef()
 				}
 				if err != nil {
@@ -267,7 +267,7 @@ func TestReassemblingTimeout(t *testing.T) {
 					p := pkt(len(frag.data), frag.data)
 					defer p.DecRef()
 					pkt, _, done, err := f.Process(FragmentID{}, frag.first, frag.last, frag.more, protocol, p)
-					if !pkt.IsNil() {
+					if pkt != nil {
 						pkt.DecRef()
 					}
 					if err != nil {
@@ -450,7 +450,7 @@ func TestErrors(t *testing.T) {
 			f := NewFragmentation(test.blockSize, HighFragThreshold, LowFragThreshold, reassembleTimeout, c, nil)
 			resPkt, _, done, err := f.Process(FragmentID{}, test.first, test.last, test.more, 0, p0)
 
-			if !resPkt.IsNil() {
+			if resPkt != nil {
 				resPkt.DecRef()
 			}
 			if !errors.Is(err, test.err) {
@@ -689,11 +689,11 @@ func TestTimeoutHandler(t *testing.T) {
 				f.release(r, true)
 			}
 			switch {
-			case !handler.pkt.IsNil() && test.wantPkt.IsNil():
+			case handler.pkt != nil && test.wantPkt == nil:
 				t.Errorf("got handler.pkt = not nil (pkt.Data = %x), want = nil", handler.pkt.Data().AsRange().ToSlice())
-			case handler.pkt.IsNil() && !test.wantPkt.IsNil():
+			case handler.pkt == nil && test.wantPkt != nil:
 				t.Errorf("got handler.pkt = nil, want = not nil (pkt.Data = %x)", test.wantPkt.Data().AsRange().ToSlice())
-			case !handler.pkt.IsNil() && !test.wantPkt.IsNil():
+			case handler.pkt != nil && test.wantPkt != nil:
 				if diff := cmp.Diff(test.wantPkt.Data().AsRange().ToSlice(), handler.pkt.Data().AsRange().ToSlice()); diff != "" {
 					t.Errorf("pkt.Data mismatch (-want, +got):\n%s", diff)
 				}

diff --git a/pkg/tcpip/network/internal/fragmentation/reassembler.go b/pkg/tcpip/network/internal/fragmentation/reassembler.go
@@ -145,7 +145,7 @@ func (r *reassembler) process(first, last uint16, more bool, proto uint8, pkt *s
 		// options received in the first fragment should be used - and they should
 		// override options from following fragments.
 		if first == 0 {
-			if !r.pkt.IsNil() {
+			if r.pkt != nil {
 				r.pkt.DecRef()
 			}
 			r.pkt = pkt.IncRef()

diff --git a/pkg/tcpip/network/internal/fragmentation/reassembler_test.go b/pkg/tcpip/network/internal/fragmentation/reassembler_test.go
@@ -191,19 +191,19 @@ func TestReassemblerProcess(t *testing.T) {
 			// reassembler will leak PacketBuffers.
 			defer func() {
 				for _, h := range r.holes {
-					if !h.pkt.IsNil() {
+					if h.pkt != nil {
 						h.pkt.DecRef()
 					}
 				}
-				if !r.pkt.IsNil() {
+				if r.pkt != nil {
 					r.pkt.DecRef()
 				}
 			}()
 			var resPkt *stack.PacketBuffer
 			var isDone bool
 			for _, param := range test.params {
 				pkt, _, done, _, err := r.process(param.first, param.last, param.more, proto, param.pkt)
-				if !pkt.IsNil() {
+				if pkt != nil {
 					defer pkt.DecRef()
 				}
 				if done != param.wantDone || err != param.wantError {
@@ -217,7 +217,7 @@ func TestReassemblerProcess(t *testing.T) {
 
 			ignorePkt := func(a, b *stack.PacketBuffer) bool { return true }
 			cmpPktData := func(a, b *stack.PacketBuffer) bool {
-				if a.IsNil() || b.IsNil() {
+				if a == nil || b == nil {
 					return a == b
 				}
 				return bytes.Equal(a.Data().AsRange().ToSlice(), b.Data().AsRange().ToSlice())
@@ -246,16 +246,16 @@ func TestReassemblerProcess(t *testing.T) {
 			}
 		})
 		for _, p := range test.params {
-			if !p.pkt.IsNil() {
+			if p.pkt != nil {
 				p.pkt.DecRef()
 			}
 		}
 		for _, w := range test.want {
-			if !w.pkt.IsNil() {
+			if w.pkt != nil {
 				w.pkt.DecRef()
 			}
 		}
-		if !test.wantPkt.IsNil() {
+		if test.wantPkt != nil {
 			test.wantPkt.DecRef()
 		}
 	}

diff --git a/pkg/tcpip/network/internal/testutil/testutil.go b/pkg/tcpip/network/internal/testutil/testutil.go
@@ -234,7 +234,7 @@ func ValidateIGMPv3RecordsAcrossReports(t *testing.T, e *channel.Endpoint, srcAd
 
 	for len(expectedRecords) != 0 {
 		p := e.Read()
-		if p.IsNil() {
+		if p == nil {
 			t.Fatalf("expected IGMP message with expectedRecords = %#v", expectedRecords)
 		}
 		v := stack.PayloadSince(p.NetworkHeader())
@@ -265,7 +265,7 @@ func ValidMultipleIGMPv2ReportLeaves(t *testing.T, e *channel.Endpoint, srcAddr
 
 	for len(expectedGroups) != 0 {
 		p := e.Read()
-		if p.IsNil() {
+		if p == nil {
 			t.Fatalf("expected IGMP message with expectedGroups = %#v", expectedGroups)
 		}
 		v := stack.PayloadSince(p.NetworkHeader())
@@ -334,7 +334,7 @@ func ValidateMLDv2RecordsAcrossReports(t *testing.T, e *channel.Endpoint, srcAdd
 
 	for len(expectedRecords) != 0 {
 		p := e.Read()
-		if p.IsNil() {
+		if p == nil {
 			t.Fatalf("expected MLD Message with expectedRecords = %#v", expectedRecords)
 		}
 		v := stack.PayloadSince(p.NetworkHeader())
@@ -365,7 +365,7 @@ func ValidMultipleMLDv1ReportLeaves(t *testing.T, e *channel.Endpoint, srcAddr t
 
 	for len(expectedGroups) != 0 {
 		p := e.Read()
-		if p.IsNil() {
+		if p == nil {
 			t.Fatalf("expected MLD Message with expectedGroups = %#v", expectedGroups)
 		}
 		v := stack.PayloadSince(p.NetworkHeader())

diff --git a/pkg/tcpip/network/ip_test.go b/pkg/tcpip/network/ip_test.go
@@ -1799,7 +1799,7 @@ func TestWriteHeaderIncludedPacket(t *testing.T) {
 					}
 
 					pkt := e.Read()
-					if pkt.IsNil() {
+					if pkt == nil {
 						t.Fatal("expected a packet to be written")
 					}
 					test.checker(t, pkt, subTest.srcAddr)
@@ -2055,7 +2055,7 @@ func TestICMPInclusionSize(t *testing.T) {
 			})
 			v := test.injector(e, test.srcAddress, payload)
 			pkt := e.Read()
-			if pkt.IsNil() {
+			if pkt == nil {
 				t.Fatal("expected a packet to be written")
 			}
 			if got, want := pkt.Size(), test.replyLength; got != want {

diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go
@@ -816,7 +816,7 @@ func (p *protocol) OnReassemblyTimeout(pkt *stack.PacketBuffer) {
 	//
 	//   If fragment zero is not available then no time exceeded need be sent at
 	//   all.
-	if !pkt.IsNil() {
+	if pkt != nil {
 		p.returnError(&icmpReasonReassemblyTimeout{}, pkt, true /* deliveredLocally */)
 	}
 }
diff --git a/pkg/tcpip/network/ipv4/igmp_test.go b/pkg/tcpip/network/ipv4/igmp_test.go
@@ -174,7 +174,7 @@ func TestIGMPV1Present(t *testing.T) {
 	// the IGMPv1 General Membership Query in.
 	{
 		p := e.Read()
-		if p.IsNil() {
+		if p == nil {
 			t.Fatal("unable to Read IGMP packet, expected V3MembershipReport")
 		}
 		if got := s.Stats().IGMP.PacketsSent.V3MembershipReport.Value(); got != 1 {
@@ -203,13 +203,13 @@ func TestIGMPV1Present(t *testing.T) {
 
 	// Verify the solicited Membership Report is sent. Now that this NIC has seen
 	// an IGMPv1 query, it should send an IGMPv1 Membership Report.
-	if p := e.Read(); !p.IsNil() {
+	if p := e.Read(); p != nil {
 		t.Fatalf("sent unexpected packet, expected V1MembershipReport only after advancing the clock = %+v", p)
 	}
 	ctx.clock.Advance(ipv4.UnsolicitedReportIntervalMax)
 	{
 		p := e.Read()
-		if p.IsNil() {
+		if p == nil {
 			t.Fatal("unable to Read IGMP packet, expected V1MembershipReport")
 		}
 		if got := s.Stats().IGMP.PacketsSent.V1MembershipReport.Value(); got != 1 {
@@ -228,7 +228,7 @@ func TestIGMPV1Present(t *testing.T) {
 	}
 	{
 		p := e.Read()
-		if p.IsNil() {
+		if p == nil {
 			t.Fatal("unable to Read IGMP packet, expected V2MembershipReport")
 		}
 		if got := s.Stats().IGMP.PacketsSent.V3MembershipReport.Value(); got != 2 {
@@ -322,7 +322,7 @@ func TestSendQueuedIGMPReports(t *testing.T) {
 				}
 			}
 			test.checkStats(t, s, reportCounter, doneCounter, reportV2Counter)
-			if p := e.Read(); !p.IsNil() {
+			if p := e.Read(); p != nil {
 				t.Fatalf("got unexpected packet = %#v", p)
 			}
 
@@ -358,7 +358,7 @@ func TestSendQueuedIGMPReports(t *testing.T) {
 			// Should have no more packets to send after the initial set of unsolicited
 			// reports.
 			clock.Advance(time.Hour)
-			if p := e.Read(); !p.IsNil() {
+			if p := e.Read(); p != nil {
 				t.Fatalf("got unexpected packet = %#v", p)
 			}
 		})
@@ -540,7 +540,7 @@ func TestGetSetIGMPVersion(t *testing.T) {
 	if err := s.JoinGroup(ipv4.ProtocolNumber, nicID, multicastAddr1); err != nil {
 		t.Fatalf("JoinGroup(ipv4, nic, %s) = %s", multicastAddr1, err)
 	}
-	if p := e.Read(); p.IsNil() {
+	if p := e.Read(); p == nil {
 		t.Fatal("expected a report message to be sent")
 	} else {
 		validateIgmpv3ReportPacket(t, p, stackAddr, multicastAddr1)
@@ -556,7 +556,7 @@ func TestGetSetIGMPVersion(t *testing.T) {
 	if err := s.JoinGroup(ipv4.ProtocolNumber, nicID, multicastAddr2); err != nil {
 		t.Fatalf("JoinGroup(ipv4, nic, %s) = %s", multicastAddr2, err)
 	}
-	if p := e.Read(); p.IsNil() {
+	if p := e.Read(); p == nil {
 		t.Fatal("expected a report message to be sent")
 	} else {
 		validateIgmpPacket(t, p, header.IGMPv2MembershipReport, 0, stackAddr, multicastAddr2, multicastAddr2)
@@ -572,7 +572,7 @@ func TestGetSetIGMPVersion(t *testing.T) {
 	if err := s.JoinGroup(ipv4.ProtocolNumber, nicID, multicastAddr3); err != nil {
 		t.Fatalf("JoinGroup(ipv4, nic, %s) = %s", multicastAddr3, err)
 	}
-	if p := e.Read(); p.IsNil() {
+	if p := e.Read(); p == nil {
 		t.Fatal("expected a report message to be sent")
 	} else {
 		validateIgmpPacket(t, p, header.IGMPv1MembershipReport, 0, stackAddr, multicastAddr3, multicastAddr3)
@@ -588,7 +588,7 @@ func TestGetSetIGMPVersion(t *testing.T) {
 	if err := s.JoinGroup(ipv4.ProtocolNumber, nicID, multicastAddr4); err != nil {
 		t.Fatalf("JoinGroup(ipv4, nic, %s) = %s", multicastAddr4, err)
 	}
-	if p := e.Read(); p.IsNil() {
+	if p := e.Read(); p == nil {
 		t.Fatal("expected a report message to be sent")
 	} else {
 		validateIgmpv3ReportPacket(t, p, stackAddr, multicastAddr4)