1 files changed, 110 insertions, 0 deletions
diff --git a/pkg/tcpip/link/pipe/pipe.go b/pkg/tcpip/link/pipe/pipe.go
new file mode 100644
index 000000000..25c364391
--- /dev/null
+++ b/pkg/tcpip/link/pipe/pipe.go
@@ -0,0 +1,110 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package pipe provides the implementation of pipe-like data-link layer
+// endpoints. Such endpoints allow packets to be sent between two interfaces.
+package pipe
+
+import (
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+)
+
+var _ stack.LinkEndpoint = (*Endpoint)(nil)
+
+// New returns both ends of a new pipe.
+func New(linkAddr1, linkAddr2 tcpip.LinkAddress) (*Endpoint, *Endpoint) {
+	ep1 := &Endpoint{
+		linkAddr: linkAddr1,
+	}
+	ep2 := &Endpoint{
+		linkAddr: linkAddr2,
+	}
+	ep1.linked = ep2
+	ep2.linked = ep1
+	return ep1, ep2
+}
+
+// Endpoint is one end of a pipe.
+type Endpoint struct {
+	dispatcher stack.NetworkDispatcher
+	linked     *Endpoint
+	linkAddr   tcpip.LinkAddress
+}
+
+// WritePacket implements stack.LinkEndpoint.
+func (e *Endpoint) WritePacket(r *stack.Route, _ *stack.GSO, proto tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) *tcpip.Error {
+	if !e.linked.IsAttached() {
+		return nil
+	}
+
+	// Note that the local address from the perspective of this endpoint is the
+	// remote address from the perspective of the other end of the pipe
+	// (e.linked). Similarly, the remote address from the perspective of this
+	// endpoint is the local address on the other end.
+	e.linked.dispatcher.DeliverNetworkPacket(r.LocalLinkAddress /* remote */, r.RemoteLinkAddress() /* local */, proto, stack.NewPacketBuffer(stack.PacketBufferOptions{
+		Data: buffer.NewVectorisedView(pkt.Size(), pkt.Views()),
+	}))
+
+	return nil
+}
+
+// WritePackets implements stack.LinkEndpoint.
+func (*Endpoint) WritePackets(*stack.Route, *stack.GSO, stack.PacketBufferList, tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
+	panic("not implemented")
+}
+
+// Attach implements stack.LinkEndpoint.
+func (e *Endpoint) Attach(dispatcher stack.NetworkDispatcher) {
+	e.dispatcher = dispatcher
+}
+
+// IsAttached implements stack.LinkEndpoint.
+func (e *Endpoint) IsAttached() bool {
+	return e.dispatcher != nil
+}
+
+// Wait implements stack.LinkEndpoint.
+func (*Endpoint) Wait() {}
+
+// MTU implements stack.LinkEndpoint.
+func (*Endpoint) MTU() uint32 {
+	return header.IPv6MinimumMTU
+}
+
+// Capabilities implements stack.LinkEndpoint.
+func (*Endpoint) Capabilities() stack.LinkEndpointCapabilities {
+	return 0
+}
+
+// MaxHeaderLength implements stack.LinkEndpoint.
+func (*Endpoint) MaxHeaderLength() uint16 {
+	return 0
+}
+
+// LinkAddress implements stack.LinkEndpoint.
+func (e *Endpoint) LinkAddress() tcpip.LinkAddress {
+	return e.linkAddr
+}
+
+// ARPHardwareType implements stack.LinkEndpoint.
+func (*Endpoint) ARPHardwareType() header.ARPHardwareType {
+	return header.ARPHardwareNone
+}
+
+// AddHeader implements stack.LinkEndpoint.
+func (*Endpoint) AddHeader(_, _ tcpip.LinkAddress, _ tcpip.NetworkProtocolNumber, _ *stack.PacketBuffer) {
+}