2 files changed, 38 insertions, 12 deletions
diff --git a/pkg/tcpip/link/loopback/BUILD b/pkg/tcpip/link/loopback/BUILD
index 47a54845c..f35fcdff4 100644
--- a/pkg/tcpip/link/loopback/BUILD
+++ b/pkg/tcpip/link/loopback/BUILD
@@ -6,10 +6,11 @@ go_library(
     name = "loopback",
     srcs = ["loopback.go"],
     importpath = "gvisor.dev/gvisor/pkg/tcpip/link/loopback",
-    visibility = ["//:sandbox"],
+    visibility = ["//visibility:public"],
     deps = [
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
+        "//pkg/tcpip/header",
         "//pkg/tcpip/stack",
     ],
 )
diff --git a/pkg/tcpip/link/loopback/loopback.go b/pkg/tcpip/link/loopback/loopback.go
index b36629d2c..499cc608f 100644
--- a/pkg/tcpip/link/loopback/loopback.go
+++ b/pkg/tcpip/link/loopback/loopback.go
@@ -23,6 +23,7 @@ package loopback
 import (
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
@@ -70,21 +71,45 @@ func (*endpoint) LinkAddress() tcpip.LinkAddress {
 	return ""
 }
 
+// Wait implements stack.LinkEndpoint.Wait.
+func (*endpoint) Wait() {}
+
 // WritePacket implements stack.LinkEndpoint.WritePacket. It delivers outbound
 // packets to the network-layer dispatcher.
-func (e *endpoint) WritePacket(_ *stack.Route, _ *stack.GSO, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) *tcpip.Error {
-	views := make([]buffer.View, 1, 1+len(payload.Views()))
-	views[0] = hdr.View()
-	views = append(views, payload.Views()...)
-	vv := buffer.NewVectorisedView(len(views[0])+payload.Size(), views)
+func (e *endpoint) WritePacket(_ *stack.Route, _ *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) *tcpip.Error {
+	views := make([]buffer.View, 1, 1+len(pkt.Data.Views()))
+	views[0] = pkt.Header.View()
+	views = append(views, pkt.Data.Views()...)
 
-	// Because we're immediately turning around and writing the packet back to the
-	// rx path, we intentionally don't preserve the remote and local link
-	// addresses from the stack.Route we're passed.
-	e.dispatcher.DeliverNetworkPacket(e, "" /* remote */, "" /* local */, protocol, vv)
+	// Because we're immediately turning around and writing the packet back
+	// to the rx path, we intentionally don't preserve the remote and local
+	// link addresses from the stack.Route we're passed.
+	e.dispatcher.DeliverNetworkPacket(e, "" /* remote */, "" /* local */, protocol, tcpip.PacketBuffer{
+		Data: buffer.NewVectorisedView(len(views[0])+pkt.Data.Size(), views),
+	})
 
 	return nil
 }
 
-// Wait implements stack.LinkEndpoint.Wait.
-func (*endpoint) Wait() {}
+// WritePackets implements stack.LinkEndpoint.WritePackets.
+func (e *endpoint) WritePackets(*stack.Route, *stack.GSO, []tcpip.PacketBuffer, tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
+	panic("not implemented")
+}
+
+// WriteRawPacket implements stack.LinkEndpoint.WriteRawPacket.
+func (e *endpoint) WriteRawPacket(vv buffer.VectorisedView) *tcpip.Error {
+	// Reject the packet if it's shorter than an ethernet header.
+	if vv.Size() < header.EthernetMinimumSize {
+		return tcpip.ErrBadAddress
+	}
+
+	// There should be an ethernet header at the beginning of vv.
+	linkHeader := header.Ethernet(vv.First()[:header.EthernetMinimumSize])
+	vv.TrimFront(len(linkHeader))
+	e.dispatcher.DeliverNetworkPacket(e, "" /* remote */, "" /* local */, linkHeader.Type(), tcpip.PacketBuffer{
+		Data:       vv,
+		LinkHeader: buffer.View(linkHeader),
+	})
+
+	return nil
+}