Internal change.

PiperOrigin-RevId: 232937200
Change-Id: I5c3709cc8f1313313ff618a45e48c14a3a111cb4

1 files changed, 103 insertions, 0 deletions

diff --git a/pkg/tcpip/link/muxed/injectable.go b/pkg/tcpip/link/muxed/injectable.go
new file mode 100644
index 000000000..1215ba1e7
--- /dev/null
+++ b/pkg/tcpip/link/muxed/injectable.go
@@ -0,0 +1,103 @@
+// Copyright 2019 Google LLC
+//
+// 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 injectable provides a muxed injectable endpoint.
+package injectable
+
+import (
+	"gvisor.googlesource.com/gvisor/pkg/tcpip"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/buffer"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/stack"
+)
+
+// MuxedInjectableEndpoint 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 MuxedInjectableEndpoint struct {
+	routes     map[tcpip.Address]stack.InjectableLinkEndpoint
+	dispatcher stack.NetworkDispatcher
+}
+
+// MTU implements stack.LinkEndpoint.
+func (m *MuxedInjectableEndpoint) 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 *MuxedInjectableEndpoint) Capabilities() stack.LinkEndpointCapabilities {
+	minCapabilities := stack.LinkEndpointCapabilities(^uint(0))
+	for _, endpoint := range m.routes {
+		minCapabilities &= endpoint.Capabilities()
+	}
+	return minCapabilities
+}
+
+// MaxHeaderLength implements stack.LinkEndpoint.
+func (m *MuxedInjectableEndpoint) 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 *MuxedInjectableEndpoint) LinkAddress() tcpip.LinkAddress {
+	return ""
+}
+
+// Attach implements stack.LinkEndpoint.
+func (m *MuxedInjectableEndpoint) Attach(dispatcher stack.NetworkDispatcher) {
+	for _, endpoint := range m.routes {
+		endpoint.Attach(dispatcher)
+	}
+	m.dispatcher = dispatcher
+}
+
+// IsAttached implements stack.LinkEndpoint.
+func (m *MuxedInjectableEndpoint) IsAttached() bool {
+	return m.dispatcher != nil
+}
+
+// Inject implements stack.InjectableLinkEndpoint.
+func (m *MuxedInjectableEndpoint) Inject(protocol tcpip.NetworkProtocolNumber, vv buffer.VectorisedView) {
+	m.dispatcher.DeliverNetworkPacket(m, "" /* remote */, "" /* local */, protocol, vv)
+}
+
+// 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 *MuxedInjectableEndpoint) WritePacket(r *stack.Route, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) *tcpip.Error {
+	if endpoint, ok := m.routes[r.RemoteAddress]; ok {
+		return endpoint.WritePacket(r, hdr, payload, protocol)
+	}
+	return tcpip.ErrNoRoute
+}
+
+// NewMuxedInjectableEndpoint creates a new multi-fd-based injectable endpoint.
+func NewMuxedInjectableEndpoint(routes map[tcpip.Address]stack.InjectableLinkEndpoint, mtu uint32) (tcpip.LinkEndpointID, *MuxedInjectableEndpoint) {
+	e := &MuxedInjectableEndpoint{
+		routes: routes,
+	}
+	return stack.RegisterLinkEndpoint(e), e
+}