Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 133 insertions, 0 deletions

diff --git a/pkg/tcpip/stack/route.go b/pkg/tcpip/stack/route.go
new file mode 100644
index 000000000..12f5efba5
--- /dev/null
+++ b/pkg/tcpip/stack/route.go
@@ -0,0 +1,133 @@
+// Copyright 2016 The Netstack Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package stack
+
+import (
+	"gvisor.googlesource.com/gvisor/pkg/sleep"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/buffer"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/header"
+)
+
+// Route represents a route through the networking stack to a given destination.
+type Route struct {
+	// RemoteAddress is the final destination of the route.
+	RemoteAddress tcpip.Address
+
+	// RemoteLinkAddress is the link-layer (MAC) address of the
+	// final destination of the route.
+	RemoteLinkAddress tcpip.LinkAddress
+
+	// LocalAddress is the local address where the route starts.
+	LocalAddress tcpip.Address
+
+	// LocalLinkAddress is the link-layer (MAC) address of the
+	// where the route starts.
+	LocalLinkAddress tcpip.LinkAddress
+
+	// NextHop is the next node in the path to the destination.
+	NextHop tcpip.Address
+
+	// NetProto is the network-layer protocol.
+	NetProto tcpip.NetworkProtocolNumber
+
+	// ref a reference to the network endpoint through which the route
+	// starts.
+	ref *referencedNetworkEndpoint
+}
+
+// makeRoute initializes a new route. It takes ownership of the provided
+// reference to a network endpoint.
+func makeRoute(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr tcpip.Address, ref *referencedNetworkEndpoint) Route {
+	return Route{
+		NetProto:      netProto,
+		LocalAddress:  localAddr,
+		RemoteAddress: remoteAddr,
+		ref:           ref,
+	}
+}
+
+// NICID returns the id of the NIC from which this route originates.
+func (r *Route) NICID() tcpip.NICID {
+	return r.ref.ep.NICID()
+}
+
+// MaxHeaderLength forwards the call to the network endpoint's implementation.
+func (r *Route) MaxHeaderLength() uint16 {
+	return r.ref.ep.MaxHeaderLength()
+}
+
+// PseudoHeaderChecksum forwards the call to the network endpoint's
+// implementation.
+func (r *Route) PseudoHeaderChecksum(protocol tcpip.TransportProtocolNumber) uint16 {
+	return header.PseudoHeaderChecksum(protocol, r.LocalAddress, r.RemoteAddress)
+}
+
+// Capabilities returns the link-layer capabilities of the route.
+func (r *Route) Capabilities() LinkEndpointCapabilities {
+	return r.ref.ep.Capabilities()
+}
+
+// Resolve attempts to resolve the link address if necessary. Returns ErrWouldBlock in
+// case address resolution requires blocking, e.g. wait for ARP reply. Waker is
+// notified when address resolution is complete (success or not).
+func (r *Route) Resolve(waker *sleep.Waker) *tcpip.Error {
+	if !r.IsResolutionRequired() {
+		// Nothing to do if there is no cache (which does the resolution on cache miss) or
+		// link address is already known.
+		return nil
+	}
+
+	nextAddr := r.NextHop
+	if nextAddr == "" {
+		nextAddr = r.RemoteAddress
+	}
+	linkAddr, err := r.ref.linkCache.GetLinkAddress(r.ref.nic.ID(), nextAddr, r.LocalAddress, r.NetProto, waker)
+	if err != nil {
+		return err
+	}
+	r.RemoteLinkAddress = linkAddr
+	return nil
+}
+
+// RemoveWaker removes a waker that has been added in Resolve().
+func (r *Route) RemoveWaker(waker *sleep.Waker) {
+	nextAddr := r.NextHop
+	if nextAddr == "" {
+		nextAddr = r.RemoteAddress
+	}
+	r.ref.linkCache.RemoveWaker(r.ref.nic.ID(), nextAddr, waker)
+}
+
+// IsResolutionRequired returns true if Resolve() must be called to resolve
+// the link address before the this route can be written to.
+func (r *Route) IsResolutionRequired() bool {
+	return r.ref.linkCache != nil && r.RemoteLinkAddress == ""
+}
+
+// WritePacket writes the packet through the given route.
+func (r *Route) WritePacket(hdr *buffer.Prependable, payload buffer.View, protocol tcpip.TransportProtocolNumber) *tcpip.Error {
+	return r.ref.ep.WritePacket(r, hdr, payload, protocol)
+}
+
+// MTU returns the MTU of the underlying network endpoint.
+func (r *Route) MTU() uint32 {
+	return r.ref.ep.MTU()
+}
+
+// Release frees all resources associated with the route.
+func (r *Route) Release() {
+	if r.ref != nil {
+		r.ref.decRef()
+		r.ref = nil
+	}
+}
+
+// Clone Clone a route such that the original one can be released and the new
+// one will remain valid.
+func (r *Route) Clone() Route {
+	r.ref.incRef()
+	return *r
+}