Move tcpip.PacketBuffer and IPTables to stack package.

This is a precursor to be being able to build an intrusive list
of PacketBuffers for use in queuing disciplines being implemented.

Updates #2214

PiperOrigin-RevId: 302677662

12 files changed, 65 insertions, 68 deletions

diff --git a/pkg/tcpip/network/arp/arp.go b/pkg/tcpip/network/arp/arp.go
index e9fcc89a8..255098372 100644
--- a/pkg/tcpip/network/arp/arp.go
+++ b/pkg/tcpip/network/arp/arp.go
@@ -79,20 +79,20 @@ func (e *endpoint) MaxHeaderLength() uint16 {
 
 func (e *endpoint) Close() {}
 
-func (e *endpoint) WritePacket(*stack.Route, *stack.GSO, stack.NetworkHeaderParams, tcpip.PacketBuffer) *tcpip.Error {
+func (e *endpoint) WritePacket(*stack.Route, *stack.GSO, stack.NetworkHeaderParams, stack.PacketBuffer) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }
 
 // WritePackets implements stack.NetworkEndpoint.WritePackets.
-func (e *endpoint) WritePackets(*stack.Route, *stack.GSO, []tcpip.PacketBuffer, stack.NetworkHeaderParams) (int, *tcpip.Error) {
+func (e *endpoint) WritePackets(*stack.Route, *stack.GSO, []stack.PacketBuffer, stack.NetworkHeaderParams) (int, *tcpip.Error) {
 	return 0, tcpip.ErrNotSupported
 }
 
-func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt stack.PacketBuffer) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }
 
-func (e *endpoint) HandlePacket(r *stack.Route, pkt tcpip.PacketBuffer) {
+func (e *endpoint) HandlePacket(r *stack.Route, pkt stack.PacketBuffer) {
 	v := pkt.Data.First()
 	h := header.ARP(v)
 	if !h.IsValid() {
@@ -113,7 +113,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt tcpip.PacketBuffer) {
 		copy(packet.ProtocolAddressSender(), h.ProtocolAddressTarget())
 		copy(packet.HardwareAddressTarget(), h.HardwareAddressSender())
 		copy(packet.ProtocolAddressTarget(), h.ProtocolAddressSender())
-		e.linkEP.WritePacket(r, nil /* gso */, ProtocolNumber, tcpip.PacketBuffer{
+		e.linkEP.WritePacket(r, nil /* gso */, ProtocolNumber, stack.PacketBuffer{
 			Header: hdr,
 		})
 		fallthrough // also fill the cache from requests
@@ -167,7 +167,7 @@ func (*protocol) LinkAddressRequest(addr, localAddr tcpip.Address, linkEP stack.
 	copy(h.ProtocolAddressSender(), localAddr)
 	copy(h.ProtocolAddressTarget(), addr)
 
-	return linkEP.WritePacket(r, nil /* gso */, ProtocolNumber, tcpip.PacketBuffer{
+	return linkEP.WritePacket(r, nil /* gso */, ProtocolNumber, stack.PacketBuffer{
 		Header: hdr,
 	})
 }
diff --git a/pkg/tcpip/network/arp/arp_test.go b/pkg/tcpip/network/arp/arp_test.go
index 03cf03b6d..b3e239ac7 100644
--- a/pkg/tcpip/network/arp/arp_test.go
+++ b/pkg/tcpip/network/arp/arp_test.go
@@ -103,7 +103,7 @@ func TestDirectRequest(t *testing.T) {
 
 	inject := func(addr tcpip.Address) {
 		copy(h.ProtocolAddressTarget(), addr)
-		c.linkEP.InjectInbound(arp.ProtocolNumber, tcpip.PacketBuffer{
+		c.linkEP.InjectInbound(arp.ProtocolNumber, stack.PacketBuffer{
 			Data: v.ToVectorisedView(),
 		})
 	}
diff --git a/pkg/tcpip/network/ip_test.go b/pkg/tcpip/network/ip_test.go
index f4d78f8c6..4950d69fc 100644
--- a/pkg/tcpip/network/ip_test.go
+++ b/pkg/tcpip/network/ip_test.go
@@ -96,7 +96,7 @@ func (t *testObject) checkValues(protocol tcpip.TransportProtocolNumber, vv buff
 // DeliverTransportPacket is called by network endpoints after parsing incoming
 // packets. This is used by the test object to verify that the results of the
 // parsing are expected.
-func (t *testObject) DeliverTransportPacket(r *stack.Route, protocol tcpip.TransportProtocolNumber, pkt tcpip.PacketBuffer) {
+func (t *testObject) DeliverTransportPacket(r *stack.Route, protocol tcpip.TransportProtocolNumber, pkt stack.PacketBuffer) {
 	t.checkValues(protocol, pkt.Data, r.RemoteAddress, r.LocalAddress)
 	t.dataCalls++
 }
@@ -104,7 +104,7 @@ func (t *testObject) DeliverTransportPacket(r *stack.Route, protocol tcpip.Trans
 // DeliverTransportControlPacket is called by network endpoints after parsing
 // incoming control (ICMP) packets. This is used by the test object to verify
 // that the results of the parsing are expected.
-func (t *testObject) DeliverTransportControlPacket(local, remote tcpip.Address, net tcpip.NetworkProtocolNumber, trans tcpip.TransportProtocolNumber, typ stack.ControlType, extra uint32, pkt tcpip.PacketBuffer) {
+func (t *testObject) DeliverTransportControlPacket(local, remote tcpip.Address, net tcpip.NetworkProtocolNumber, trans tcpip.TransportProtocolNumber, typ stack.ControlType, extra uint32, pkt stack.PacketBuffer) {
 	t.checkValues(trans, pkt.Data, remote, local)
 	if typ != t.typ {
 		t.t.Errorf("typ = %v, want %v", typ, t.typ)
@@ -150,7 +150,7 @@ func (*testObject) Wait() {}
 // WritePacket is called by network endpoints after producing a packet and
 // writing it to the link endpoint. This is used by the test object to verify
 // that the produced packet is as expected.
-func (t *testObject) WritePacket(_ *stack.Route, _ *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (t *testObject) WritePacket(_ *stack.Route, _ *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt stack.PacketBuffer) *tcpip.Error {
 	var prot tcpip.TransportProtocolNumber
 	var srcAddr tcpip.Address
 	var dstAddr tcpip.Address
@@ -172,7 +172,7 @@ func (t *testObject) WritePacket(_ *stack.Route, _ *stack.GSO, protocol tcpip.Ne
 }
 
 // WritePackets implements stack.LinkEndpoint.WritePackets.
-func (t *testObject) WritePackets(_ *stack.Route, _ *stack.GSO, pkt []tcpip.PacketBuffer, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
+func (t *testObject) WritePackets(_ *stack.Route, _ *stack.GSO, pkt []stack.PacketBuffer, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
 	panic("not implemented")
 }
 
@@ -246,7 +246,7 @@ func TestIPv4Send(t *testing.T) {
 	if err != nil {
 		t.Fatalf("could not find route: %v", err)
 	}
-	if err := ep.WritePacket(&r, nil /* gso */, stack.NetworkHeaderParams{Protocol: 123, TTL: 123, TOS: stack.DefaultTOS}, tcpip.PacketBuffer{
+	if err := ep.WritePacket(&r, nil /* gso */, stack.NetworkHeaderParams{Protocol: 123, TTL: 123, TOS: stack.DefaultTOS}, stack.PacketBuffer{
 		Header: hdr,
 		Data:   payload.ToVectorisedView(),
 	}); err != nil {
@@ -289,7 +289,7 @@ func TestIPv4Receive(t *testing.T) {
 	if err != nil {
 		t.Fatalf("could not find route: %v", err)
 	}
-	ep.HandlePacket(&r, tcpip.PacketBuffer{
+	ep.HandlePacket(&r, stack.PacketBuffer{
 		Data: view.ToVectorisedView(),
 	})
 	if o.dataCalls != 1 {
@@ -379,7 +379,7 @@ func TestIPv4ReceiveControl(t *testing.T) {
 			o.extra = c.expectedExtra
 
 			vv := view[:len(view)-c.trunc].ToVectorisedView()
-			ep.HandlePacket(&r, tcpip.PacketBuffer{
+			ep.HandlePacket(&r, stack.PacketBuffer{
 				Data: vv,
 			})
 			if want := c.expectedCount; o.controlCalls != want {
@@ -444,7 +444,7 @@ func TestIPv4FragmentationReceive(t *testing.T) {
 	}
 
 	// Send first segment.
-	ep.HandlePacket(&r, tcpip.PacketBuffer{
+	ep.HandlePacket(&r, stack.PacketBuffer{
 		Data: frag1.ToVectorisedView(),
 	})
 	if o.dataCalls != 0 {
@@ -452,7 +452,7 @@ func TestIPv4FragmentationReceive(t *testing.T) {
 	}
 
 	// Send second segment.
-	ep.HandlePacket(&r, tcpip.PacketBuffer{
+	ep.HandlePacket(&r, stack.PacketBuffer{
 		Data: frag2.ToVectorisedView(),
 	})
 	if o.dataCalls != 1 {
@@ -487,7 +487,7 @@ func TestIPv6Send(t *testing.T) {
 	if err != nil {
 		t.Fatalf("could not find route: %v", err)
 	}
-	if err := ep.WritePacket(&r, nil /* gso */, stack.NetworkHeaderParams{Protocol: 123, TTL: 123, TOS: stack.DefaultTOS}, tcpip.PacketBuffer{
+	if err := ep.WritePacket(&r, nil /* gso */, stack.NetworkHeaderParams{Protocol: 123, TTL: 123, TOS: stack.DefaultTOS}, stack.PacketBuffer{
 		Header: hdr,
 		Data:   payload.ToVectorisedView(),
 	}); err != nil {
@@ -530,7 +530,7 @@ func TestIPv6Receive(t *testing.T) {
 		t.Fatalf("could not find route: %v", err)
 	}
 
-	ep.HandlePacket(&r, tcpip.PacketBuffer{
+	ep.HandlePacket(&r, stack.PacketBuffer{
 		Data: view.ToVectorisedView(),
 	})
 	if o.dataCalls != 1 {
@@ -644,7 +644,7 @@ func TestIPv6ReceiveControl(t *testing.T) {
 			// Set ICMPv6 checksum.
 			icmp.SetChecksum(header.ICMPv6Checksum(icmp, outerSrcAddr, localIpv6Addr, buffer.VectorisedView{}))
 
-			ep.HandlePacket(&r, tcpip.PacketBuffer{
+			ep.HandlePacket(&r, stack.PacketBuffer{
 				Data: view[:len(view)-c.trunc].ToVectorisedView(),
 			})
 			if want := c.expectedCount; o.controlCalls != want {
diff --git a/pkg/tcpip/network/ipv4/BUILD b/pkg/tcpip/network/ipv4/BUILD
index 0fef2b1f1..880ea7de2 100644
--- a/pkg/tcpip/network/ipv4/BUILD
+++ b/pkg/tcpip/network/ipv4/BUILD
@@ -13,7 +13,6 @@ go_library(
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/header",
-        "//pkg/tcpip/iptables",
         "//pkg/tcpip/network/fragmentation",
         "//pkg/tcpip/network/hash",
         "//pkg/tcpip/stack",
diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go
index 32bf39e43..c4bf1ba5c 100644
--- a/pkg/tcpip/network/ipv4/icmp.go
+++ b/pkg/tcpip/network/ipv4/icmp.go
@@ -15,7 +15,6 @@
 package ipv4
 
 import (
-	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
@@ -25,7 +24,7 @@ import (
 // the original packet that caused the ICMP one to be sent. This information is
 // used to find out which transport endpoint must be notified about the ICMP
 // packet.
-func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt tcpip.PacketBuffer) {
+func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt stack.PacketBuffer) {
 	h := header.IPv4(pkt.Data.First())
 
 	// We don't use IsValid() here because ICMP only requires that the IP
@@ -53,7 +52,7 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt tcpip.
 	e.dispatcher.DeliverTransportControlPacket(e.id.LocalAddress, h.DestinationAddress(), ProtocolNumber, p, typ, extra, pkt)
 }
 
-func (e *endpoint) handleICMP(r *stack.Route, pkt tcpip.PacketBuffer) {
+func (e *endpoint) handleICMP(r *stack.Route, pkt stack.PacketBuffer) {
 	stats := r.Stats()
 	received := stats.ICMP.V4PacketsReceived
 	v := pkt.Data.First()
@@ -85,7 +84,7 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt tcpip.PacketBuffer) {
 
 		// It's possible that a raw socket expects to receive this.
 		h.SetChecksum(wantChecksum)
-		e.dispatcher.DeliverTransportPacket(r, header.ICMPv4ProtocolNumber, tcpip.PacketBuffer{
+		e.dispatcher.DeliverTransportPacket(r, header.ICMPv4ProtocolNumber, stack.PacketBuffer{
 			Data:          pkt.Data.Clone(nil),
 			NetworkHeader: append(buffer.View(nil), pkt.NetworkHeader...),
 		})
@@ -99,7 +98,7 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt tcpip.PacketBuffer) {
 		pkt.SetChecksum(0)
 		pkt.SetChecksum(^header.Checksum(pkt, header.ChecksumVV(vv, 0)))
 		sent := stats.ICMP.V4PacketsSent
-		if err := r.WritePacket(nil /* gso */, stack.NetworkHeaderParams{Protocol: header.ICMPv4ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS}, tcpip.PacketBuffer{
+		if err := r.WritePacket(nil /* gso */, stack.NetworkHeaderParams{Protocol: header.ICMPv4ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS}, stack.PacketBuffer{
 			Header:          hdr,
 			Data:            vv,
 			TransportHeader: buffer.View(pkt),
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go
index 4f1742938..b3ee6000e 100644
--- a/pkg/tcpip/network/ipv4/ipv4.go
+++ b/pkg/tcpip/network/ipv4/ipv4.go
@@ -26,7 +26,6 @@ import (
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
-	"gvisor.dev/gvisor/pkg/tcpip/iptables"
 	"gvisor.dev/gvisor/pkg/tcpip/network/fragmentation"
 	"gvisor.dev/gvisor/pkg/tcpip/network/hash"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
@@ -125,7 +124,7 @@ func (e *endpoint) GSOMaxSize() uint32 {
 // packet's stated length matches the length of the header+payload. mtu
 // includes the IP header and options. This does not support the DontFragment
 // IP flag.
-func (e *endpoint) writePacketFragments(r *stack.Route, gso *stack.GSO, mtu int, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (e *endpoint) writePacketFragments(r *stack.Route, gso *stack.GSO, mtu int, pkt stack.PacketBuffer) *tcpip.Error {
 	// This packet is too big, it needs to be fragmented.
 	ip := header.IPv4(pkt.Header.View())
 	flags := ip.Flags()
@@ -165,7 +164,7 @@ func (e *endpoint) writePacketFragments(r *stack.Route, gso *stack.GSO, mtu int,
 		if i > 0 {
 			newPayload := pkt.Data.Clone(nil)
 			newPayload.CapLength(innerMTU)
-			if err := e.linkEP.WritePacket(r, gso, ProtocolNumber, tcpip.PacketBuffer{
+			if err := e.linkEP.WritePacket(r, gso, ProtocolNumber, stack.PacketBuffer{
 				Header:        pkt.Header,
 				Data:          newPayload,
 				NetworkHeader: buffer.View(h),
@@ -184,7 +183,7 @@ func (e *endpoint) writePacketFragments(r *stack.Route, gso *stack.GSO, mtu int,
 			newPayload := pkt.Data.Clone(nil)
 			newPayloadLength := outerMTU - pkt.Header.UsedLength()
 			newPayload.CapLength(newPayloadLength)
-			if err := e.linkEP.WritePacket(r, gso, ProtocolNumber, tcpip.PacketBuffer{
+			if err := e.linkEP.WritePacket(r, gso, ProtocolNumber, stack.PacketBuffer{
 				Header:        pkt.Header,
 				Data:          newPayload,
 				NetworkHeader: buffer.View(h),
@@ -198,7 +197,7 @@ func (e *endpoint) writePacketFragments(r *stack.Route, gso *stack.GSO, mtu int,
 			startOfHdr := pkt.Header
 			startOfHdr.TrimBack(pkt.Header.UsedLength() - outerMTU)
 			emptyVV := buffer.NewVectorisedView(0, []buffer.View{})
-			if err := e.linkEP.WritePacket(r, gso, ProtocolNumber, tcpip.PacketBuffer{
+			if err := e.linkEP.WritePacket(r, gso, ProtocolNumber, stack.PacketBuffer{
 				Header:        startOfHdr,
 				Data:          emptyVV,
 				NetworkHeader: buffer.View(h),
@@ -241,7 +240,7 @@ func (e *endpoint) addIPHeader(r *stack.Route, hdr *buffer.Prependable, payloadS
 }
 
 // WritePacket writes a packet to the given destination address and protocol.
-func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.NetworkHeaderParams, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.NetworkHeaderParams, pkt stack.PacketBuffer) *tcpip.Error {
 	ip := e.addIPHeader(r, &pkt.Header, pkt.Data.Size(), params)
 	pkt.NetworkHeader = buffer.View(ip)
 
@@ -253,7 +252,7 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.Netw
 		views = append(views, pkt.Data.Views()...)
 		loopedR := r.MakeLoopedRoute()
 
-		e.HandlePacket(&loopedR, tcpip.PacketBuffer{
+		e.HandlePacket(&loopedR, stack.PacketBuffer{
 			Data: buffer.NewVectorisedView(len(views[0])+pkt.Data.Size(), views),
 		})
 
@@ -273,7 +272,7 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.Netw
 }
 
 // WritePackets implements stack.NetworkEndpoint.WritePackets.
-func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.PacketBuffer, params stack.NetworkHeaderParams) (int, *tcpip.Error) {
+func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []stack.PacketBuffer, params stack.NetworkHeaderParams) (int, *tcpip.Error) {
 	if r.Loop&stack.PacketLoop != 0 {
 		panic("multiple packets in local loop")
 	}
@@ -292,7 +291,7 @@ func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.Pac
 
 // WriteHeaderIncludedPacket writes a packet already containing a network
 // header through the given route.
-func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt stack.PacketBuffer) *tcpip.Error {
 	// The packet already has an IP header, but there are a few required
 	// checks.
 	ip := header.IPv4(pkt.Data.First())
@@ -344,7 +343,7 @@ func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt tcpip.PacketBuf
 
 // HandlePacket is called by the link layer when new ipv4 packets arrive for
 // this endpoint.
-func (e *endpoint) HandlePacket(r *stack.Route, pkt tcpip.PacketBuffer) {
+func (e *endpoint) HandlePacket(r *stack.Route, pkt stack.PacketBuffer) {
 	headerView := pkt.Data.First()
 	h := header.IPv4(headerView)
 	if !h.IsValid(pkt.Data.Size()) {
@@ -361,7 +360,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt tcpip.PacketBuffer) {
 	// iptables filtering. All packets that reach here are intended for
 	// this machine and will not be forwarded.
 	ipt := e.stack.IPTables()
-	if ok := ipt.Check(iptables.Input, pkt); !ok {
+	if ok := ipt.Check(stack.Input, pkt); !ok {
 		// iptables is telling us to drop the packet.
 		return
 	}
diff --git a/pkg/tcpip/network/ipv4/ipv4_test.go b/pkg/tcpip/network/ipv4/ipv4_test.go
index e900f1b45..5a864d832 100644
--- a/pkg/tcpip/network/ipv4/ipv4_test.go
+++ b/pkg/tcpip/network/ipv4/ipv4_test.go
@@ -113,7 +113,7 @@ func makeHdrAndPayload(hdrLength int, extraLength int, viewSizes []int) (buffer.
 
 // comparePayloads compared the contents of all the packets against the contents
 // of the source packet.
-func compareFragments(t *testing.T, packets []tcpip.PacketBuffer, sourcePacketInfo tcpip.PacketBuffer, mtu uint32) {
+func compareFragments(t *testing.T, packets []stack.PacketBuffer, sourcePacketInfo stack.PacketBuffer, mtu uint32) {
 	t.Helper()
 	// Make a complete array of the sourcePacketInfo packet.
 	source := header.IPv4(packets[0].Header.View()[:header.IPv4MinimumSize])
@@ -173,7 +173,7 @@ func compareFragments(t *testing.T, packets []tcpip.PacketBuffer, sourcePacketIn
 
 type errorChannel struct {
 	*channel.Endpoint
-	Ch                    chan tcpip.PacketBuffer
+	Ch                    chan stack.PacketBuffer
 	packetCollectorErrors []*tcpip.Error
 }
 
@@ -183,7 +183,7 @@ type errorChannel struct {
 func newErrorChannel(size int, mtu uint32, linkAddr tcpip.LinkAddress, packetCollectorErrors []*tcpip.Error) *errorChannel {
 	return &errorChannel{
 		Endpoint:              channel.New(size, mtu, linkAddr),
-		Ch:                    make(chan tcpip.PacketBuffer, size),
+		Ch:                    make(chan stack.PacketBuffer, size),
 		packetCollectorErrors: packetCollectorErrors,
 	}
 }
@@ -202,7 +202,7 @@ func (e *errorChannel) Drain() int {
 }
 
 // WritePacket stores outbound packets into the channel.
-func (e *errorChannel) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (e *errorChannel) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt stack.PacketBuffer) *tcpip.Error {
 	select {
 	case e.Ch <- pkt:
 	default:
@@ -281,13 +281,13 @@ func TestFragmentation(t *testing.T) {
 	for _, ft := range fragTests {
 		t.Run(ft.description, func(t *testing.T) {
 			hdr, payload := makeHdrAndPayload(ft.hdrLength, ft.extraLength, ft.payloadViewsSizes)
-			source := tcpip.PacketBuffer{
+			source := stack.PacketBuffer{
 				Header: hdr,
 				// Save the source payload because WritePacket will modify it.
 				Data: payload.Clone(nil),
 			}
 			c := buildContext(t, nil, ft.mtu)
-			err := c.Route.WritePacket(ft.gso, stack.NetworkHeaderParams{Protocol: tcp.ProtocolNumber, TTL: 42, TOS: stack.DefaultTOS}, tcpip.PacketBuffer{
+			err := c.Route.WritePacket(ft.gso, stack.NetworkHeaderParams{Protocol: tcp.ProtocolNumber, TTL: 42, TOS: stack.DefaultTOS}, stack.PacketBuffer{
 				Header: hdr,
 				Data:   payload,
 			})
@@ -295,7 +295,7 @@ func TestFragmentation(t *testing.T) {
 				t.Errorf("err got %v, want %v", err, nil)
 			}
 
-			var results []tcpip.PacketBuffer
+			var results []stack.PacketBuffer
 		L:
 			for {
 				select {
@@ -337,7 +337,7 @@ func TestFragmentationErrors(t *testing.T) {
 		t.Run(ft.description, func(t *testing.T) {
 			hdr, payload := makeHdrAndPayload(ft.hdrLength, header.IPv4MinimumSize, ft.payloadViewsSizes)
 			c := buildContext(t, ft.packetCollectorErrors, ft.mtu)
-			err := c.Route.WritePacket(&stack.GSO{}, stack.NetworkHeaderParams{Protocol: tcp.ProtocolNumber, TTL: 42, TOS: stack.DefaultTOS}, tcpip.PacketBuffer{
+			err := c.Route.WritePacket(&stack.GSO{}, stack.NetworkHeaderParams{Protocol: tcp.ProtocolNumber, TTL: 42, TOS: stack.DefaultTOS}, stack.PacketBuffer{
 				Header: hdr,
 				Data:   payload,
 			})
@@ -459,7 +459,7 @@ func TestInvalidFragments(t *testing.T) {
 			s.CreateNIC(nicID, sniffer.New(ep))
 
 			for _, pkt := range tc.packets {
-				ep.InjectLinkAddr(header.IPv4ProtocolNumber, remoteLinkAddr, tcpip.PacketBuffer{
+				ep.InjectLinkAddr(header.IPv4ProtocolNumber, remoteLinkAddr, stack.PacketBuffer{
 					Data: buffer.NewVectorisedView(len(pkt), []buffer.View{pkt}),
 				})
 			}
diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go
index 45dc757c7..8640feffc 100644
--- a/pkg/tcpip/network/ipv6/icmp.go
+++ b/pkg/tcpip/network/ipv6/icmp.go
@@ -27,7 +27,7 @@ import (
 // the original packet that caused the ICMP one to be sent. This information is
 // used to find out which transport endpoint must be notified about the ICMP
 // packet.
-func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt tcpip.PacketBuffer) {
+func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt stack.PacketBuffer) {
 	h := header.IPv6(pkt.Data.First())
 
 	// We don't use IsValid() here because ICMP only requires that up to
@@ -62,7 +62,7 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt tcpip.
 	e.dispatcher.DeliverTransportControlPacket(e.id.LocalAddress, h.DestinationAddress(), ProtocolNumber, p, typ, extra, pkt)
 }
 
-func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt tcpip.PacketBuffer) {
+func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.PacketBuffer) {
 	stats := r.Stats().ICMP
 	sent := stats.V6PacketsSent
 	received := stats.V6PacketsReceived
@@ -243,7 +243,7 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt tcpip.P
 		//
 		// The IP Hop Limit field has a value of 255, i.e., the packet
 		// could not possibly have been forwarded by a router.
-		if err := r.WritePacket(nil /* gso */, stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: header.NDPHopLimit, TOS: stack.DefaultTOS}, tcpip.PacketBuffer{
+		if err := r.WritePacket(nil /* gso */, stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: header.NDPHopLimit, TOS: stack.DefaultTOS}, stack.PacketBuffer{
 			Header: hdr,
 		}); err != nil {
 			sent.Dropped.Increment()
@@ -330,7 +330,7 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt tcpip.P
 		copy(packet, h)
 		packet.SetType(header.ICMPv6EchoReply)
 		packet.SetChecksum(header.ICMPv6Checksum(packet, r.LocalAddress, r.RemoteAddress, pkt.Data))
-		if err := r.WritePacket(nil /* gso */, stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS}, tcpip.PacketBuffer{
+		if err := r.WritePacket(nil /* gso */, stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS}, stack.PacketBuffer{
 			Header: hdr,
 			Data:   pkt.Data,
 		}); err != nil {
@@ -463,7 +463,7 @@ func (*protocol) LinkAddressRequest(addr, localAddr tcpip.Address, linkEP stack.
 	})
 
 	// TODO(stijlist): count this in ICMP stats.
-	return linkEP.WritePacket(r, nil /* gso */, ProtocolNumber, tcpip.PacketBuffer{
+	return linkEP.WritePacket(r, nil /* gso */, ProtocolNumber, stack.PacketBuffer{
 		Header: hdr,
 	})
 }
diff --git a/pkg/tcpip/network/ipv6/icmp_test.go b/pkg/tcpip/network/ipv6/icmp_test.go
index 50c4b6474..bae09ed94 100644
--- a/pkg/tcpip/network/ipv6/icmp_test.go
+++ b/pkg/tcpip/network/ipv6/icmp_test.go
@@ -56,7 +56,7 @@ func (*stubLinkEndpoint) LinkAddress() tcpip.LinkAddress {
 	return ""
 }
 
-func (*stubLinkEndpoint) WritePacket(*stack.Route, *stack.GSO, tcpip.NetworkProtocolNumber, tcpip.PacketBuffer) *tcpip.Error {
+func (*stubLinkEndpoint) WritePacket(*stack.Route, *stack.GSO, tcpip.NetworkProtocolNumber, stack.PacketBuffer) *tcpip.Error {
 	return nil
 }
 
@@ -66,7 +66,7 @@ type stubDispatcher struct {
 	stack.TransportDispatcher
 }
 
-func (*stubDispatcher) DeliverTransportPacket(*stack.Route, tcpip.TransportProtocolNumber, tcpip.PacketBuffer) {
+func (*stubDispatcher) DeliverTransportPacket(*stack.Route, tcpip.TransportProtocolNumber, stack.PacketBuffer) {
 }
 
 type stubLinkAddressCache struct {
@@ -187,7 +187,7 @@ func TestICMPCounts(t *testing.T) {
 			SrcAddr:       r.LocalAddress,
 			DstAddr:       r.RemoteAddress,
 		})
-		ep.HandlePacket(&r, tcpip.PacketBuffer{
+		ep.HandlePacket(&r, stack.PacketBuffer{
 			Data: hdr.View().ToVectorisedView(),
 		})
 	}
@@ -326,7 +326,7 @@ func routeICMPv6Packet(t *testing.T, args routeArgs, fn func(*testing.T, header.
 		views := []buffer.View{pi.Pkt.Header.View(), pi.Pkt.Data.ToView()}
 		size := pi.Pkt.Header.UsedLength() + pi.Pkt.Data.Size()
 		vv := buffer.NewVectorisedView(size, views)
-		args.dst.InjectLinkAddr(pi.Proto, args.dst.LinkAddress(), tcpip.PacketBuffer{
+		args.dst.InjectLinkAddr(pi.Proto, args.dst.LinkAddress(), stack.PacketBuffer{
 			Data: vv,
 		})
 	}
@@ -561,7 +561,7 @@ func TestICMPChecksumValidationSimple(t *testing.T) {
 					SrcAddr:       lladdr1,
 					DstAddr:       lladdr0,
 				})
-				e.InjectInbound(ProtocolNumber, tcpip.PacketBuffer{
+				e.InjectInbound(ProtocolNumber, stack.PacketBuffer{
 					Data: hdr.View().ToVectorisedView(),
 				})
 			}
@@ -738,7 +738,7 @@ func TestICMPChecksumValidationWithPayload(t *testing.T) {
 					SrcAddr:       lladdr1,
 					DstAddr:       lladdr0,
 				})
-				e.InjectInbound(ProtocolNumber, tcpip.PacketBuffer{
+				e.InjectInbound(ProtocolNumber, stack.PacketBuffer{
 					Data: hdr.View().ToVectorisedView(),
 				})
 			}
@@ -916,7 +916,7 @@ func TestICMPChecksumValidationWithPayloadMultipleViews(t *testing.T) {
 					SrcAddr:       lladdr1,
 					DstAddr:       lladdr0,
 				})
-				e.InjectInbound(ProtocolNumber, tcpip.PacketBuffer{
+				e.InjectInbound(ProtocolNumber, stack.PacketBuffer{
 					Data: buffer.NewVectorisedView(header.IPv6MinimumSize+size+payloadSize, []buffer.View{hdr.View(), payload}),
 				})
 			}
diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go
index 9aef5234b..29e597002 100644
--- a/pkg/tcpip/network/ipv6/ipv6.go
+++ b/pkg/tcpip/network/ipv6/ipv6.go
@@ -112,7 +112,7 @@ func (e *endpoint) addIPHeader(r *stack.Route, hdr *buffer.Prependable, payloadS
 }
 
 // WritePacket writes a packet to the given destination address and protocol.
-func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.NetworkHeaderParams, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.NetworkHeaderParams, pkt stack.PacketBuffer) *tcpip.Error {
 	ip := e.addIPHeader(r, &pkt.Header, pkt.Data.Size(), params)
 	pkt.NetworkHeader = buffer.View(ip)
 
@@ -124,7 +124,7 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.Netw
 		views = append(views, pkt.Data.Views()...)
 		loopedR := r.MakeLoopedRoute()
 
-		e.HandlePacket(&loopedR, tcpip.PacketBuffer{
+		e.HandlePacket(&loopedR, stack.PacketBuffer{
 			Data: buffer.NewVectorisedView(len(views[0])+pkt.Data.Size(), views),
 		})
 
@@ -139,7 +139,7 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.Netw
 }
 
 // WritePackets implements stack.LinkEndpoint.WritePackets.
-func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.PacketBuffer, params stack.NetworkHeaderParams) (int, *tcpip.Error) {
+func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []stack.PacketBuffer, params stack.NetworkHeaderParams) (int, *tcpip.Error) {
 	if r.Loop&stack.PacketLoop != 0 {
 		panic("not implemented")
 	}
@@ -161,14 +161,14 @@ func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.Pac
 
 // WriteHeaderIncludedPacker implements stack.NetworkEndpoint. It is not yet
 // supported by IPv6.
-func (*endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (*endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt stack.PacketBuffer) *tcpip.Error {
 	// TODO(b/146666412): Support IPv6 header-included packets.
 	return tcpip.ErrNotSupported
 }
 
 // HandlePacket is called by the link layer when new ipv6 packets arrive for
 // this endpoint.
-func (e *endpoint) HandlePacket(r *stack.Route, pkt tcpip.PacketBuffer) {
+func (e *endpoint) HandlePacket(r *stack.Route, pkt stack.PacketBuffer) {
 	headerView := pkt.Data.First()
 	h := header.IPv6(headerView)
 	if !h.IsValid(pkt.Data.Size()) {
diff --git a/pkg/tcpip/network/ipv6/ipv6_test.go b/pkg/tcpip/network/ipv6/ipv6_test.go
index 1cbfa7278..ed98ef22a 100644
--- a/pkg/tcpip/network/ipv6/ipv6_test.go
+++ b/pkg/tcpip/network/ipv6/ipv6_test.go
@@ -55,7 +55,7 @@ func testReceiveICMP(t *testing.T, s *stack.Stack, e *channel.Endpoint, src, dst
 		DstAddr:       dst,
 	})
 
-	e.InjectInbound(ProtocolNumber, tcpip.PacketBuffer{
+	e.InjectInbound(ProtocolNumber, stack.PacketBuffer{
 		Data: hdr.View().ToVectorisedView(),
 	})
 
@@ -113,7 +113,7 @@ func testReceiveUDP(t *testing.T, s *stack.Stack, e *channel.Endpoint, src, dst
 		DstAddr:       dst,
 	})
 
-	e.InjectInbound(ProtocolNumber, tcpip.PacketBuffer{
+	e.InjectInbound(ProtocolNumber, stack.PacketBuffer{
 		Data: hdr.View().ToVectorisedView(),
 	})
 
diff --git a/pkg/tcpip/network/ipv6/ndp_test.go b/pkg/tcpip/network/ipv6/ndp_test.go
index c9395de52..f924ed9e1 100644
--- a/pkg/tcpip/network/ipv6/ndp_test.go
+++ b/pkg/tcpip/network/ipv6/ndp_test.go
@@ -135,7 +135,7 @@ func TestNeighorSolicitationWithSourceLinkLayerOption(t *testing.T) {
 				t.Fatalf("got invalid = %d, want = 0", got)
 			}
 
-			e.InjectInbound(ProtocolNumber, tcpip.PacketBuffer{
+			e.InjectInbound(ProtocolNumber, stack.PacketBuffer{
 				Data: hdr.View().ToVectorisedView(),
 			})
 
@@ -238,7 +238,7 @@ func TestNeighorAdvertisementWithTargetLinkLayerOption(t *testing.T) {
 				t.Fatalf("got invalid = %d, want = 0", got)
 			}
 
-			e.InjectInbound(ProtocolNumber, tcpip.PacketBuffer{
+			e.InjectInbound(ProtocolNumber, stack.PacketBuffer{
 				Data: hdr.View().ToVectorisedView(),
 			})
 
@@ -304,7 +304,7 @@ func TestHopLimitValidation(t *testing.T) {
 			SrcAddr:       r.LocalAddress,
 			DstAddr:       r.RemoteAddress,
 		})
-		ep.HandlePacket(r, tcpip.PacketBuffer{
+		ep.HandlePacket(r, stack.PacketBuffer{
 			Data: hdr.View().ToVectorisedView(),
 		})
 	}
@@ -588,7 +588,7 @@ func TestRouterAdvertValidation(t *testing.T) {
 				t.Fatalf("got rxRA = %d, want = 0", got)
 			}
 
-			e.InjectInbound(header.IPv6ProtocolNumber, tcpip.PacketBuffer{
+			e.InjectInbound(header.IPv6ProtocolNumber, stack.PacketBuffer{
 				Data: hdr.View().ToVectorisedView(),
 			})