1 files changed, 137 insertions, 0 deletions
diff --git a/pkg/tcpip/link/muxed/injectable.go b/pkg/tcpip/link/muxed/injectable.go
new file mode 100755
index 000000000..445b22c17
--- /dev/null
+++ b/pkg/tcpip/link/muxed/injectable.go
@@ -0,0 +1,137 @@
+// Copyright 2019 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 muxed provides a muxed link endpoints.
+package muxed
+
+import (
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+)
+
+// InjectableEndpoint is an injectable multi endpoint. The endpoint has
+// trivial routing rules that determine which InjectableEndpoint a given packet
+// will be written to. Note that HandleLocal works differently for this
+// endpoint (see WritePacket).
+type InjectableEndpoint struct {
+	routes     map[tcpip.Address]stack.InjectableLinkEndpoint
+	dispatcher stack.NetworkDispatcher
+}
+
+// MTU implements stack.LinkEndpoint.
+func (m *InjectableEndpoint) MTU() uint32 {
+	minMTU := ^uint32(0)
+	for _, endpoint := range m.routes {
+		if endpointMTU := endpoint.MTU(); endpointMTU < minMTU {
+			minMTU = endpointMTU
+		}
+	}
+	return minMTU
+}
+
+// Capabilities implements stack.LinkEndpoint.
+func (m *InjectableEndpoint) Capabilities() stack.LinkEndpointCapabilities {
+	minCapabilities := stack.LinkEndpointCapabilities(^uint(0))
+	for _, endpoint := range m.routes {
+		minCapabilities &= endpoint.Capabilities()
+	}
+	return minCapabilities
+}
+
+// MaxHeaderLength implements stack.LinkEndpoint.
+func (m *InjectableEndpoint) MaxHeaderLength() uint16 {
+	minHeaderLen := ^uint16(0)
+	for _, endpoint := range m.routes {
+		if headerLen := endpoint.MaxHeaderLength(); headerLen < minHeaderLen {
+			minHeaderLen = headerLen
+		}
+	}
+	return minHeaderLen
+}
+
+// LinkAddress implements stack.LinkEndpoint.
+func (m *InjectableEndpoint) LinkAddress() tcpip.LinkAddress {
+	return ""
+}
+
+// Attach implements stack.LinkEndpoint.
+func (m *InjectableEndpoint) Attach(dispatcher stack.NetworkDispatcher) {
+	for _, endpoint := range m.routes {
+		endpoint.Attach(dispatcher)
+	}
+	m.dispatcher = dispatcher
+}
+
+// IsAttached implements stack.LinkEndpoint.
+func (m *InjectableEndpoint) IsAttached() bool {
+	return m.dispatcher != nil
+}
+
+// InjectInbound implements stack.InjectableLinkEndpoint.
+func (m *InjectableEndpoint) InjectInbound(protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) {
+	m.dispatcher.DeliverNetworkPacket(m, "" /* remote */, "" /* local */, protocol, pkt)
+}
+
+// WritePackets writes outbound packets to the appropriate
+// LinkInjectableEndpoint based on the RemoteAddress. HandleLocal only works if
+// r.RemoteAddress has a route registered in this endpoint.
+func (m *InjectableEndpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.PacketBuffer, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
+	endpoint, ok := m.routes[r.RemoteAddress]
+	if !ok {
+		return 0, tcpip.ErrNoRoute
+	}
+	return endpoint.WritePackets(r, gso, pkts, protocol)
+}
+
+// WritePacket writes outbound packets to the appropriate LinkInjectableEndpoint
+// based on the RemoteAddress. HandleLocal only works if r.RemoteAddress has a
+// route registered in this endpoint.
+func (m *InjectableEndpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) *tcpip.Error {
+	if endpoint, ok := m.routes[r.RemoteAddress]; ok {
+		return endpoint.WritePacket(r, gso, protocol, pkt)
+	}
+	return tcpip.ErrNoRoute
+}
+
+// WriteRawPacket implements stack.LinkEndpoint.WriteRawPacket.
+func (m *InjectableEndpoint) WriteRawPacket(buffer.VectorisedView) *tcpip.Error {
+	// WriteRawPacket doesn't get a route or network address, so there's
+	// nowhere to write this.
+	return tcpip.ErrNoRoute
+}
+
+// InjectOutbound writes outbound packets to the appropriate
+// LinkInjectableEndpoint based on the dest address.
+func (m *InjectableEndpoint) InjectOutbound(dest tcpip.Address, packet []byte) *tcpip.Error {
+	endpoint, ok := m.routes[dest]
+	if !ok {
+		return tcpip.ErrNoRoute
+	}
+	return endpoint.InjectOutbound(dest, packet)
+}
+
+// Wait implements stack.LinkEndpoint.Wait.
+func (m *InjectableEndpoint) Wait() {
+	for _, ep := range m.routes {
+		ep.Wait()
+	}
+}
+
+// NewInjectableEndpoint creates a new multi-endpoint injectable endpoint.
+func NewInjectableEndpoint(routes map[tcpip.Address]stack.InjectableLinkEndpoint) *InjectableEndpoint {
+	return &InjectableEndpoint{
+		routes: routes,
+	}
+}