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-rw-r--r--pkg/tcpip/packet_buffer.go8
-rw-r--r--pkg/tcpip/stack/BUILD2
-rw-r--r--pkg/tcpip/stack/forwarder.go131
-rw-r--r--pkg/tcpip/stack/forwarder_test.go635
-rw-r--r--pkg/tcpip/stack/nic.go51
-rw-r--r--pkg/tcpip/stack/stack.go5
-rw-r--r--pkg/tcpip/stack/stack_test.go112
-rw-r--r--pkg/tcpip/stack/transport_test.go4
8 files changed, 886 insertions, 62 deletions
diff --git a/pkg/tcpip/packet_buffer.go b/pkg/tcpip/packet_buffer.go
index ab24372e7..04852132c 100644
--- a/pkg/tcpip/packet_buffer.go
+++ b/pkg/tcpip/packet_buffer.go
@@ -39,8 +39,12 @@ type PacketBuffer struct {
// payload.
DataSize int
- // Header holds the headers of outbound packets. As a packet is passed
- // down the stack, each layer adds to Header.
+ // Header holds the headers of outbound packets generated by the netstack. As
+ // a packet is passed down the stack, each layer adds to Header.
+ //
+ // Note, if a packet is being forwarded at the IP layer, the headers for the
+ // IP layer and above (transport) will be held in Data as the packet was not
+ // passed down the stack it arrived at before being forwarded.
Header buffer.Prependable
// These fields are used by both inbound and outbound packets. They
diff --git a/pkg/tcpip/stack/BUILD b/pkg/tcpip/stack/BUILD
index 8febd54c8..6c029b2fb 100644
--- a/pkg/tcpip/stack/BUILD
+++ b/pkg/tcpip/stack/BUILD
@@ -19,6 +19,7 @@ go_library(
name = "stack",
srcs = [
"dhcpv6configurationfromndpra_string.go",
+ "forwarder.go",
"icmp_rate_limit.go",
"linkaddrcache.go",
"linkaddrentry_list.go",
@@ -80,6 +81,7 @@ go_test(
name = "stack_test",
size = "small",
srcs = [
+ "forwarder_test.go",
"linkaddrcache_test.go",
"nic_test.go",
],
diff --git a/pkg/tcpip/stack/forwarder.go b/pkg/tcpip/stack/forwarder.go
new file mode 100644
index 000000000..631953935
--- /dev/null
+++ b/pkg/tcpip/stack/forwarder.go
@@ -0,0 +1,131 @@
+// 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 stack
+
+import (
+ "fmt"
+
+ "gvisor.dev/gvisor/pkg/sync"
+ "gvisor.dev/gvisor/pkg/tcpip"
+)
+
+const (
+ // maxPendingResolutions is the maximum number of pending link-address
+ // resolutions.
+ maxPendingResolutions = 64
+ maxPendingPacketsPerResolution = 256
+)
+
+type pendingPacket struct {
+ nic *NIC
+ route *Route
+ proto tcpip.NetworkProtocolNumber
+ pkt tcpip.PacketBuffer
+}
+
+type forwardQueue struct {
+ sync.Mutex
+
+ // The packets to send once the resolver completes.
+ packets map[<-chan struct{}][]*pendingPacket
+
+ // FIFO of channels used to cancel the oldest goroutine waiting for
+ // link-address resolution.
+ cancelChans []chan struct{}
+}
+
+func newForwardQueue() *forwardQueue {
+ return &forwardQueue{packets: make(map[<-chan struct{}][]*pendingPacket)}
+}
+
+func (f *forwardQueue) enqueue(ch <-chan struct{}, n *NIC, r *Route, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) {
+ shouldWait := false
+
+ f.Lock()
+ packets, ok := f.packets[ch]
+ if !ok {
+ shouldWait = true
+ }
+ for len(packets) == maxPendingPacketsPerResolution {
+ p := packets[0]
+ packets = packets[1:]
+ p.nic.stack.stats.IP.OutgoingPacketErrors.Increment()
+ p.route.Release()
+ }
+ if l := len(packets); l >= maxPendingPacketsPerResolution {
+ panic(fmt.Sprintf("max pending packets for resolution reached; got %d packets, max = %d", l, maxPendingPacketsPerResolution))
+ }
+ f.packets[ch] = append(packets, &pendingPacket{
+ nic: n,
+ route: r,
+ proto: protocol,
+ pkt: pkt,
+ })
+ f.Unlock()
+
+ if !shouldWait {
+ return
+ }
+
+ // Wait for the link-address resolution to complete.
+ // Start a goroutine with a forwarding-cancel channel so that we can
+ // limit the maximum number of goroutines running concurrently.
+ cancel := f.newCancelChannel()
+ go func() {
+ cancelled := false
+ select {
+ case <-ch:
+ case <-cancel:
+ cancelled = true
+ }
+
+ f.Lock()
+ packets := f.packets[ch]
+ delete(f.packets, ch)
+ f.Unlock()
+
+ for _, p := range packets {
+ if cancelled {
+ p.nic.stack.stats.IP.OutgoingPacketErrors.Increment()
+ } else if _, err := p.route.Resolve(nil); err != nil {
+ p.nic.stack.stats.IP.OutgoingPacketErrors.Increment()
+ } else {
+ p.nic.forwardPacket(p.route, p.proto, p.pkt)
+ }
+ p.route.Release()
+ }
+ }()
+}
+
+// newCancelChannel creates a channel that can cancel a pending forwarding
+// activity. The oldest channel is closed if the number of open channels would
+// exceed maxPendingResolutions.
+func (f *forwardQueue) newCancelChannel() chan struct{} {
+ f.Lock()
+ defer f.Unlock()
+
+ if len(f.cancelChans) == maxPendingResolutions {
+ ch := f.cancelChans[0]
+ f.cancelChans = f.cancelChans[1:]
+ close(ch)
+ }
+ if l := len(f.cancelChans); l >= maxPendingResolutions {
+ panic(fmt.Sprintf("max pending resolutions reached; got %d active resolutions, max = %d", l, maxPendingResolutions))
+ }
+
+ ch := make(chan struct{})
+ f.cancelChans = append(f.cancelChans, ch)
+ return ch
+}
diff --git a/pkg/tcpip/stack/forwarder_test.go b/pkg/tcpip/stack/forwarder_test.go
new file mode 100644
index 000000000..5a04590d5
--- /dev/null
+++ b/pkg/tcpip/stack/forwarder_test.go
@@ -0,0 +1,635 @@
+// 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 stack
+
+import (
+ "encoding/binary"
+ "math"
+ "testing"
+ "time"
+
+ "gvisor.dev/gvisor/pkg/tcpip"
+ "gvisor.dev/gvisor/pkg/tcpip/buffer"
+)
+
+const (
+ fwdTestNetNumber tcpip.NetworkProtocolNumber = math.MaxUint32
+ fwdTestNetHeaderLen = 12
+ fwdTestNetDefaultPrefixLen = 8
+
+ // fwdTestNetDefaultMTU is the MTU, in bytes, used throughout the tests,
+ // except where another value is explicitly used. It is chosen to match
+ // the MTU of loopback interfaces on linux systems.
+ fwdTestNetDefaultMTU = 65536
+)
+
+// fwdTestNetworkEndpoint is a network-layer protocol endpoint.
+// Headers of this protocol are fwdTestNetHeaderLen bytes, but we currently only
+// use the first three: destination address, source address, and transport
+// protocol. They're all one byte fields to simplify parsing.
+type fwdTestNetworkEndpoint struct {
+ nicID tcpip.NICID
+ id NetworkEndpointID
+ prefixLen int
+ proto *fwdTestNetworkProtocol
+ dispatcher TransportDispatcher
+ ep LinkEndpoint
+}
+
+func (f *fwdTestNetworkEndpoint) MTU() uint32 {
+ return f.ep.MTU() - uint32(f.MaxHeaderLength())
+}
+
+func (f *fwdTestNetworkEndpoint) NICID() tcpip.NICID {
+ return f.nicID
+}
+
+func (f *fwdTestNetworkEndpoint) PrefixLen() int {
+ return f.prefixLen
+}
+
+func (*fwdTestNetworkEndpoint) DefaultTTL() uint8 {
+ return 123
+}
+
+func (f *fwdTestNetworkEndpoint) ID() *NetworkEndpointID {
+ return &f.id
+}
+
+func (f *fwdTestNetworkEndpoint) HandlePacket(r *Route, pkt tcpip.PacketBuffer) {
+ // Consume the network header.
+ b := pkt.Data.First()
+ pkt.Data.TrimFront(fwdTestNetHeaderLen)
+
+ // Dispatch the packet to the transport protocol.
+ f.dispatcher.DeliverTransportPacket(r, tcpip.TransportProtocolNumber(b[2]), pkt)
+}
+
+func (f *fwdTestNetworkEndpoint) MaxHeaderLength() uint16 {
+ return f.ep.MaxHeaderLength() + fwdTestNetHeaderLen
+}
+
+func (f *fwdTestNetworkEndpoint) PseudoHeaderChecksum(protocol tcpip.TransportProtocolNumber, dstAddr tcpip.Address) uint16 {
+ return 0
+}
+
+func (f *fwdTestNetworkEndpoint) Capabilities() LinkEndpointCapabilities {
+ return f.ep.Capabilities()
+}
+
+func (f *fwdTestNetworkEndpoint) WritePacket(r *Route, gso *GSO, params NetworkHeaderParams, pkt tcpip.PacketBuffer) *tcpip.Error {
+ // Add the protocol's header to the packet and send it to the link
+ // endpoint.
+ b := pkt.Header.Prepend(fwdTestNetHeaderLen)
+ b[0] = r.RemoteAddress[0]
+ b[1] = f.id.LocalAddress[0]
+ b[2] = byte(params.Protocol)
+
+ return f.ep.WritePacket(r, gso, fwdTestNetNumber, pkt)
+}
+
+// WritePackets implements LinkEndpoint.WritePackets.
+func (f *fwdTestNetworkEndpoint) WritePackets(r *Route, gso *GSO, pkts []tcpip.PacketBuffer, params NetworkHeaderParams) (int, *tcpip.Error) {
+ panic("not implemented")
+}
+
+func (*fwdTestNetworkEndpoint) WriteHeaderIncludedPacket(r *Route, pkt tcpip.PacketBuffer) *tcpip.Error {
+ return tcpip.ErrNotSupported
+}
+
+func (*fwdTestNetworkEndpoint) Close() {}
+
+// fwdTestNetworkProtocol is a network-layer protocol that implements Address
+// resolution.
+type fwdTestNetworkProtocol struct {
+ addrCache *linkAddrCache
+ addrResolveDelay time.Duration
+ onLinkAddressResolved func(cache *linkAddrCache, addr tcpip.Address)
+ onResolveStaticAddress func(tcpip.Address) (tcpip.LinkAddress, bool)
+}
+
+func (f *fwdTestNetworkProtocol) Number() tcpip.NetworkProtocolNumber {
+ return fwdTestNetNumber
+}
+
+func (f *fwdTestNetworkProtocol) MinimumPacketSize() int {
+ return fwdTestNetHeaderLen
+}
+
+func (f *fwdTestNetworkProtocol) DefaultPrefixLen() int {
+ return fwdTestNetDefaultPrefixLen
+}
+
+func (*fwdTestNetworkProtocol) ParseAddresses(v buffer.View) (src, dst tcpip.Address) {
+ return tcpip.Address(v[1:2]), tcpip.Address(v[0:1])
+}
+
+func (f *fwdTestNetworkProtocol) NewEndpoint(nicID tcpip.NICID, addrWithPrefix tcpip.AddressWithPrefix, linkAddrCache LinkAddressCache, dispatcher TransportDispatcher, ep LinkEndpoint, _ *Stack) (NetworkEndpoint, *tcpip.Error) {
+ return &fwdTestNetworkEndpoint{
+ nicID: nicID,
+ id: NetworkEndpointID{LocalAddress: addrWithPrefix.Address},
+ prefixLen: addrWithPrefix.PrefixLen,
+ proto: f,
+ dispatcher: dispatcher,
+ ep: ep,
+ }, nil
+}
+
+func (f *fwdTestNetworkProtocol) SetOption(option interface{}) *tcpip.Error {
+ return tcpip.ErrUnknownProtocolOption
+}
+
+func (f *fwdTestNetworkProtocol) Option(option interface{}) *tcpip.Error {
+ return tcpip.ErrUnknownProtocolOption
+}
+
+func (f *fwdTestNetworkProtocol) Close() {}
+
+func (f *fwdTestNetworkProtocol) Wait() {}
+
+func (f *fwdTestNetworkProtocol) LinkAddressRequest(addr, localAddr tcpip.Address, linkEP LinkEndpoint) *tcpip.Error {
+ if f.addrCache != nil && f.onLinkAddressResolved != nil {
+ time.AfterFunc(f.addrResolveDelay, func() {
+ f.onLinkAddressResolved(f.addrCache, addr)
+ })
+ }
+ return nil
+}
+
+func (f *fwdTestNetworkProtocol) ResolveStaticAddress(addr tcpip.Address) (tcpip.LinkAddress, bool) {
+ if f.onResolveStaticAddress != nil {
+ return f.onResolveStaticAddress(addr)
+ }
+ return "", false
+}
+
+func (f *fwdTestNetworkProtocol) LinkAddressProtocol() tcpip.NetworkProtocolNumber {
+ return fwdTestNetNumber
+}
+
+// fwdTestPacketInfo holds all the information about an outbound packet.
+type fwdTestPacketInfo struct {
+ RemoteLinkAddress tcpip.LinkAddress
+ LocalLinkAddress tcpip.LinkAddress
+ Pkt tcpip.PacketBuffer
+}
+
+type fwdTestLinkEndpoint struct {
+ dispatcher NetworkDispatcher
+ mtu uint32
+ linkAddr tcpip.LinkAddress
+
+ // C is where outbound packets are queued.
+ C chan fwdTestPacketInfo
+}
+
+// InjectInbound injects an inbound packet.
+func (e *fwdTestLinkEndpoint) InjectInbound(protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) {
+ e.InjectLinkAddr(protocol, "", pkt)
+}
+
+// InjectLinkAddr injects an inbound packet with a remote link address.
+func (e *fwdTestLinkEndpoint) InjectLinkAddr(protocol tcpip.NetworkProtocolNumber, remote tcpip.LinkAddress, pkt tcpip.PacketBuffer) {
+ e.dispatcher.DeliverNetworkPacket(e, remote, "" /* local */, protocol, pkt)
+}
+
+// Attach saves the stack network-layer dispatcher for use later when packets
+// are injected.
+func (e *fwdTestLinkEndpoint) Attach(dispatcher NetworkDispatcher) {
+ e.dispatcher = dispatcher
+}
+
+// IsAttached implements stack.LinkEndpoint.IsAttached.
+func (e *fwdTestLinkEndpoint) IsAttached() bool {
+ return e.dispatcher != nil
+}
+
+// MTU implements stack.LinkEndpoint.MTU. It returns the value initialized
+// during construction.
+func (e *fwdTestLinkEndpoint) MTU() uint32 {
+ return e.mtu
+}
+
+// Capabilities implements stack.LinkEndpoint.Capabilities.
+func (e fwdTestLinkEndpoint) Capabilities() LinkEndpointCapabilities {
+ caps := LinkEndpointCapabilities(0)
+ return caps | CapabilityResolutionRequired
+}
+
+// GSOMaxSize returns the maximum GSO packet size.
+func (*fwdTestLinkEndpoint) GSOMaxSize() uint32 {
+ return 1 << 15
+}
+
+// MaxHeaderLength returns the maximum size of the link layer header. Given it
+// doesn't have a header, it just returns 0.
+func (*fwdTestLinkEndpoint) MaxHeaderLength() uint16 {
+ return 0
+}
+
+// LinkAddress returns the link address of this endpoint.
+func (e *fwdTestLinkEndpoint) LinkAddress() tcpip.LinkAddress {
+ return e.linkAddr
+}
+
+func (e fwdTestLinkEndpoint) WritePacket(r *Route, gso *GSO, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) *tcpip.Error {
+ p := fwdTestPacketInfo{
+ RemoteLinkAddress: r.RemoteLinkAddress,
+ LocalLinkAddress: r.LocalLinkAddress,
+ Pkt: pkt,
+ }
+
+ select {
+ case e.C <- p:
+ default:
+ }
+
+ return nil
+}
+
+// WritePackets stores outbound packets into the channel.
+func (e *fwdTestLinkEndpoint) WritePackets(r *Route, gso *GSO, pkts []tcpip.PacketBuffer, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
+ n := 0
+ for _, pkt := range pkts {
+ e.WritePacket(r, gso, protocol, pkt)
+ n++
+ }
+
+ return n, nil
+}
+
+// WriteRawPacket implements stack.LinkEndpoint.WriteRawPacket.
+func (e *fwdTestLinkEndpoint) WriteRawPacket(vv buffer.VectorisedView) *tcpip.Error {
+ p := fwdTestPacketInfo{
+ Pkt: tcpip.PacketBuffer{Data: vv},
+ }
+
+ select {
+ case e.C <- p:
+ default:
+ }
+
+ return nil
+}
+
+// Wait implements stack.LinkEndpoint.Wait.
+func (*fwdTestLinkEndpoint) Wait() {}
+
+func fwdTestNetFactory(t *testing.T, proto *fwdTestNetworkProtocol) (ep1, ep2 *fwdTestLinkEndpoint) {
+ // Create a stack with the network protocol and two NICs.
+ s := New(Options{
+ NetworkProtocols: []NetworkProtocol{proto},
+ })
+
+ proto.addrCache = s.linkAddrCache
+
+ // Enable forwarding.
+ s.SetForwarding(true)
+
+ // NIC 1 has the link address "a", and added the network address 1.
+ ep1 = &fwdTestLinkEndpoint{
+ C: make(chan fwdTestPacketInfo, 300),
+ mtu: fwdTestNetDefaultMTU,
+ linkAddr: "a",
+ }
+ if err := s.CreateNIC(1, ep1); err != nil {
+ t.Fatal("CreateNIC #1 failed:", err)
+ }
+ if err := s.AddAddress(1, fwdTestNetNumber, "\x01"); err != nil {
+ t.Fatal("AddAddress #1 failed:", err)
+ }
+
+ // NIC 2 has the link address "b", and added the network address 2.
+ ep2 = &fwdTestLinkEndpoint{
+ C: make(chan fwdTestPacketInfo, 300),
+ mtu: fwdTestNetDefaultMTU,
+ linkAddr: "b",
+ }
+ if err := s.CreateNIC(2, ep2); err != nil {
+ t.Fatal("CreateNIC #2 failed:", err)
+ }
+ if err := s.AddAddress(2, fwdTestNetNumber, "\x02"); err != nil {
+ t.Fatal("AddAddress #2 failed:", err)
+ }
+
+ // Route all packets to NIC 2.
+ {
+ subnet, err := tcpip.NewSubnet("\x00", "\x00")
+ if err != nil {
+ t.Fatal(err)
+ }
+ s.SetRouteTable([]tcpip.Route{{Destination: subnet, NIC: 2}})
+ }
+
+ return ep1, ep2
+}
+
+func TestForwardingWithStaticResolver(t *testing.T) {
+ // Create a network protocol with a static resolver.
+ proto := &fwdTestNetworkProtocol{
+ onResolveStaticAddress:
+ // The network address 3 is resolved to the link address "c".
+ func(addr tcpip.Address) (tcpip.LinkAddress, bool) {
+ if addr == "\x03" {
+ return "c", true
+ }
+ return "", false
+ },
+ }
+
+ ep1, ep2 := fwdTestNetFactory(t, proto)
+
+ // Inject an inbound packet to address 3 on NIC 1, and see if it is
+ // forwarded to NIC 2.
+ buf := buffer.NewView(30)
+ buf[0] = 3
+ ep1.InjectInbound(fwdTestNetNumber, tcpip.PacketBuffer{
+ Data: buf.ToVectorisedView(),
+ })
+
+ var p fwdTestPacketInfo
+
+ select {
+ case p = <-ep2.C:
+ default:
+ t.Fatal("packet not forwarded")
+ }
+
+ // Test that the static address resolution happened correctly.
+ if p.RemoteLinkAddress != "c" {
+ t.Fatalf("got p.RemoteLinkAddress = %s, want = c", p.RemoteLinkAddress)
+ }
+ if p.LocalLinkAddress != "b" {
+ t.Fatalf("got p.LocalLinkAddress = %s, want = b", p.LocalLinkAddress)
+ }
+}
+
+func TestForwardingWithFakeResolver(t *testing.T) {
+ // Create a network protocol with a fake resolver.
+ proto := &fwdTestNetworkProtocol{
+ addrResolveDelay: 500 * time.Millisecond,
+ onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address) {
+ // Any address will be resolved to the link address "c".
+ cache.add(tcpip.FullAddress{NIC: 2, Addr: addr}, "c")
+ },
+ }
+
+ ep1, ep2 := fwdTestNetFactory(t, proto)
+
+ // Inject an inbound packet to address 3 on NIC 1, and see if it is
+ // forwarded to NIC 2.
+ buf := buffer.NewView(30)
+ buf[0] = 3
+ ep1.InjectInbound(fwdTestNetNumber, tcpip.PacketBuffer{
+ Data: buf.ToVectorisedView(),
+ })
+
+ var p fwdTestPacketInfo
+
+ select {
+ case p = <-ep2.C:
+ case <-time.After(time.Second):
+ t.Fatal("packet not forwarded")
+ }
+
+ // Test that the address resolution happened correctly.
+ if p.RemoteLinkAddress != "c" {
+ t.Fatalf("got p.RemoteLinkAddress = %s, want = c", p.RemoteLinkAddress)
+ }
+ if p.LocalLinkAddress != "b" {
+ t.Fatalf("got p.LocalLinkAddress = %s, want = b", p.LocalLinkAddress)
+ }
+}
+
+func TestForwardingWithNoResolver(t *testing.T) {
+ // Create a network protocol without a resolver.
+ proto := &fwdTestNetworkProtocol{}
+
+ ep1, ep2 := fwdTestNetFactory(t, proto)
+
+ // inject an inbound packet to address 3 on NIC 1, and see if it is
+ // forwarded to NIC 2.
+ buf := buffer.NewView(30)
+ buf[0] = 3
+ ep1.InjectInbound(fwdTestNetNumber, tcpip.PacketBuffer{
+ Data: buf.ToVectorisedView(),
+ })
+
+ select {
+ case <-ep2.C:
+ t.Fatal("Packet should not be forwarded")
+ case <-time.After(time.Second):
+ }
+}
+
+func TestForwardingWithFakeResolverPartialTimeout(t *testing.T) {
+ // Create a network protocol with a fake resolver.
+ proto := &fwdTestNetworkProtocol{
+ addrResolveDelay: 500 * time.Millisecond,
+ onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address) {
+ // Only packets to address 3 will be resolved to the
+ // link address "c".
+ if addr == "\x03" {
+ cache.add(tcpip.FullAddress{NIC: 2, Addr: addr}, "c")
+ }
+ },
+ }
+
+ ep1, ep2 := fwdTestNetFactory(t, proto)
+
+ // Inject an inbound packet to address 4 on NIC 1. This packet should
+ // not be forwarded.
+ buf := buffer.NewView(30)
+ buf[0] = 4
+ ep1.InjectInbound(fwdTestNetNumber, tcpip.PacketBuffer{
+ Data: buf.ToVectorisedView(),
+ })
+
+ // Inject an inbound packet to address 3 on NIC 1, and see if it is
+ // forwarded to NIC 2.
+ buf = buffer.NewView(30)
+ buf[0] = 3
+ ep1.InjectInbound(fwdTestNetNumber, tcpip.PacketBuffer{
+ Data: buf.ToVectorisedView(),
+ })
+
+ var p fwdTestPacketInfo
+
+ select {
+ case p = <-ep2.C:
+ case <-time.After(time.Second):
+ t.Fatal("packet not forwarded")
+ }
+
+ b := p.Pkt.Data.First()
+ if b[0] != 3 {
+ t.Fatalf("got b[0] = %d, want = 3", b[0])
+ }
+
+ // Test that the address resolution happened correctly.
+ if p.RemoteLinkAddress != "c" {
+ t.Fatalf("got p.RemoteLinkAddress = %s, want = c", p.RemoteLinkAddress)
+ }
+ if p.LocalLinkAddress != "b" {
+ t.Fatalf("got p.LocalLinkAddress = %s, want = b", p.LocalLinkAddress)
+ }
+}
+
+func TestForwardingWithFakeResolverTwoPackets(t *testing.T) {
+ // Create a network protocol with a fake resolver.
+ proto := &fwdTestNetworkProtocol{
+ addrResolveDelay: 500 * time.Millisecond,
+ onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address) {
+ // Any packets will be resolved to the link address "c".
+ cache.add(tcpip.FullAddress{NIC: 2, Addr: addr}, "c")
+ },
+ }
+
+ ep1, ep2 := fwdTestNetFactory(t, proto)
+
+ // Inject two inbound packets to address 3 on NIC 1.
+ for i := 0; i < 2; i++ {
+ buf := buffer.NewView(30)
+ buf[0] = 3
+ ep1.InjectInbound(fwdTestNetNumber, tcpip.PacketBuffer{
+ Data: buf.ToVectorisedView(),
+ })
+ }
+
+ for i := 0; i < 2; i++ {
+ var p fwdTestPacketInfo
+
+ select {
+ case p = <-ep2.C:
+ case <-time.After(time.Second):
+ t.Fatal("packet not forwarded")
+ }
+
+ b := p.Pkt.Data.First()
+ if b[0] != 3 {
+ t.Fatalf("got b[0] = %d, want = 3", b[0])
+ }
+
+ // Test that the address resolution happened correctly.
+ if p.RemoteLinkAddress != "c" {
+ t.Fatalf("got p.RemoteLinkAddress = %s, want = c", p.RemoteLinkAddress)
+ }
+ if p.LocalLinkAddress != "b" {
+ t.Fatalf("got p.LocalLinkAddress = %s, want = b", p.LocalLinkAddress)
+ }
+ }
+}
+
+func TestForwardingWithFakeResolverManyPackets(t *testing.T) {
+ // Create a network protocol with a fake resolver.
+ proto := &fwdTestNetworkProtocol{
+ addrResolveDelay: 500 * time.Millisecond,
+ onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address) {
+ // Any packets will be resolved to the link address "c".
+ cache.add(tcpip.FullAddress{NIC: 2, Addr: addr}, "c")
+ },
+ }
+
+ ep1, ep2 := fwdTestNetFactory(t, proto)
+
+ for i := 0; i < maxPendingPacketsPerResolution+5; i++ {
+ // Inject inbound 'maxPendingPacketsPerResolution + 5' packets on NIC 1.
+ buf := buffer.NewView(30)
+ buf[0] = 3
+ // Set the packet sequence number.
+ binary.BigEndian.PutUint16(buf[fwdTestNetHeaderLen:], uint16(i))
+ ep1.InjectInbound(fwdTestNetNumber, tcpip.PacketBuffer{
+ Data: buf.ToVectorisedView(),
+ })
+ }
+
+ for i := 0; i < maxPendingPacketsPerResolution; i++ {
+ var p fwdTestPacketInfo
+
+ select {
+ case p = <-ep2.C:
+ case <-time.After(time.Second):
+ t.Fatal("packet not forwarded")
+ }
+
+ b := p.Pkt.Data.First()
+ if b[0] != 3 {
+ t.Fatalf("got b[0] = %d, want = 3", b[0])
+ }
+ // The first 5 packets should not be forwarded so the the
+ // sequemnce number should start with 5.
+ want := uint16(i + 5)
+ if n := binary.BigEndian.Uint16(b[fwdTestNetHeaderLen:]); n != want {
+ t.Fatalf("got the packet #%d, want = #%d", n, want)
+ }
+
+ // Test that the address resolution happened correctly.
+ if p.RemoteLinkAddress != "c" {
+ t.Fatalf("got p.RemoteLinkAddress = %s, want = c", p.RemoteLinkAddress)
+ }
+ if p.LocalLinkAddress != "b" {
+ t.Fatalf("got p.LocalLinkAddress = %s, want = b", p.LocalLinkAddress)
+ }
+ }
+}
+
+func TestForwardingWithFakeResolverManyResolutions(t *testing.T) {
+ // Create a network protocol with a fake resolver.
+ proto := &fwdTestNetworkProtocol{
+ addrResolveDelay: 500 * time.Millisecond,
+ onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address) {
+ // Any packets will be resolved to the link address "c".
+ cache.add(tcpip.FullAddress{NIC: 2, Addr: addr}, "c")
+ },
+ }
+
+ ep1, ep2 := fwdTestNetFactory(t, proto)
+
+ for i := 0; i < maxPendingResolutions+5; i++ {
+ // Inject inbound 'maxPendingResolutions + 5' packets on NIC 1.
+ // Each packet has a different destination address (3 to
+ // maxPendingResolutions + 7).
+ buf := buffer.NewView(30)
+ buf[0] = byte(3 + i)
+ ep1.InjectInbound(fwdTestNetNumber, tcpip.PacketBuffer{
+ Data: buf.ToVectorisedView(),
+ })
+ }
+
+ for i := 0; i < maxPendingResolutions; i++ {
+ var p fwdTestPacketInfo
+
+ select {
+ case p = <-ep2.C:
+ case <-time.After(time.Second):
+ t.Fatal("packet not forwarded")
+ }
+
+ // The first 5 packets (address 3 to 7) should not be forwarded
+ // because their address resolutions are interrupted.
+ b := p.Pkt.Data.First()
+ if b[0] < 8 {
+ t.Fatalf("got b[0] = %d, want b[0] >= 8", b[0])
+ }
+
+ // Test that the address resolution happened correctly.
+ if p.RemoteLinkAddress != "c" {
+ t.Fatalf("got p.RemoteLinkAddress = %s, want = c", p.RemoteLinkAddress)
+ }
+ if p.LocalLinkAddress != "b" {
+ t.Fatalf("got p.LocalLinkAddress = %s, want = b", p.LocalLinkAddress)
+ }
+ }
+}
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go
index 3e6196aee..e46bd86c6 100644
--- a/pkg/tcpip/stack/nic.go
+++ b/pkg/tcpip/stack/nic.go
@@ -1201,10 +1201,6 @@ func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.Link
n.stack.stats.IP.InvalidDestinationAddressesReceived.Increment()
return
}
- defer r.Release()
-
- r.LocalLinkAddress = n.linkEP.LinkAddress()
- r.RemoteLinkAddress = remote
// Found a NIC.
n := r.ref.nic
@@ -1213,24 +1209,33 @@ func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.Link
ok = ok && ref.isValidForOutgoingRLocked() && ref.tryIncRef()
n.mu.RUnlock()
if ok {
+ r.LocalLinkAddress = n.linkEP.LinkAddress()
+ r.RemoteLinkAddress = remote
r.RemoteAddress = src
// TODO(b/123449044): Update the source NIC as well.
ref.ep.HandlePacket(&r, pkt)
ref.decRef()
- } else {
- // n doesn't have a destination endpoint.
- // Send the packet out of n.
- pkt.Header = buffer.NewPrependableFromView(pkt.Data.First())
- pkt.Data.RemoveFirst()
-
- // TODO(b/128629022): use route.WritePacket.
- if err := n.linkEP.WritePacket(&r, nil /* gso */, protocol, pkt); err != nil {
- r.Stats().IP.OutgoingPacketErrors.Increment()
- } else {
- n.stats.Tx.Packets.Increment()
- n.stats.Tx.Bytes.IncrementBy(uint64(pkt.Header.UsedLength() + pkt.Data.Size()))
+ r.Release()
+ return
+ }
+
+ // n doesn't have a destination endpoint.
+ // Send the packet out of n.
+ // TODO(b/128629022): move this logic to route.WritePacket.
+ if ch, err := r.Resolve(nil); err != nil {
+ if err == tcpip.ErrWouldBlock {
+ n.stack.forwarder.enqueue(ch, n, &r, protocol, pkt)
+ // forwarder will release route.
+ return
}
+ n.stack.stats.IP.InvalidDestinationAddressesReceived.Increment()
+ r.Release()
+ return
}
+
+ // The link-address resolution finished immediately.
+ n.forwardPacket(&r, protocol, pkt)
+ r.Release()
return
}
@@ -1240,6 +1245,20 @@ func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.Link
}
}
+func (n *NIC) forwardPacket(r *Route, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) {
+ // TODO(b/143425874): Decrease the TTL field in forwarded packets.
+
+ // pkt.Header should have enough capacity to hold the link's headers.
+ pkt.Header = buffer.NewPrependable(int(n.linkEP.MaxHeaderLength()))
+ if err := n.linkEP.WritePacket(r, nil /* gso */, protocol, pkt); err != nil {
+ r.Stats().IP.OutgoingPacketErrors.Increment()
+ return
+ }
+
+ n.stats.Tx.Packets.Increment()
+ n.stats.Tx.Bytes.IncrementBy(uint64(pkt.Header.UsedLength() + pkt.Data.Size()))
+}
+
// DeliverTransportPacket delivers the packets to the appropriate transport
// protocol endpoint.
func (n *NIC) DeliverTransportPacket(r *Route, protocol tcpip.TransportProtocolNumber, pkt tcpip.PacketBuffer) {
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 13354d884..6f423874a 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -462,6 +462,10 @@ type Stack struct {
// opaqueIIDOpts hold the options for generating opaque interface identifiers
// (IIDs) as outlined by RFC 7217.
opaqueIIDOpts OpaqueInterfaceIdentifierOptions
+
+ // forwarder holds the packets that wait for their link-address resolutions
+ // to complete, and forwards them when each resolution is done.
+ forwarder *forwardQueue
}
// UniqueID is an abstract generator of unique identifiers.
@@ -641,6 +645,7 @@ func New(opts Options) *Stack {
uniqueIDGenerator: opts.UniqueID,
ndpDisp: opts.NDPDisp,
opaqueIIDOpts: opts.OpaqueIIDOpts,
+ forwarder: newForwardQueue(),
}
// Add specified network protocols.
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index e15db40fb..9515426d6 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -2240,56 +2240,84 @@ func TestNICStats(t *testing.T) {
}
func TestNICForwarding(t *testing.T) {
- // Create a stack with the fake network protocol, two NICs, each with
- // an address.
- s := stack.New(stack.Options{
- NetworkProtocols: []stack.NetworkProtocol{fakeNetFactory()},
- })
- s.SetForwarding(true)
+ const nicID1 = 1
+ const nicID2 = 2
+ const dstAddr = tcpip.Address("\x03")
- ep1 := channel.New(10, defaultMTU, "")
- if err := s.CreateNIC(1, ep1); err != nil {
- t.Fatal("CreateNIC #1 failed:", err)
- }
- if err := s.AddAddress(1, fakeNetNumber, "\x01"); err != nil {
- t.Fatal("AddAddress #1 failed:", err)
+ tests := []struct {
+ name string
+ headerLen uint16
+ }{
+ {
+ name: "Zero header length",
+ },
+ {
+ name: "Non-zero header length",
+ headerLen: 16,
+ },
}
- ep2 := channel.New(10, defaultMTU, "")
- if err := s.CreateNIC(2, ep2); err != nil {
- t.Fatal("CreateNIC #2 failed:", err)
- }
- if err := s.AddAddress(2, fakeNetNumber, "\x02"); err != nil {
- t.Fatal("AddAddress #2 failed:", err)
- }
+ for _, test := range tests {
+ t.Run(test.name, func(t *testing.T) {
+ s := stack.New(stack.Options{
+ NetworkProtocols: []stack.NetworkProtocol{fakeNetFactory()},
+ })
+ s.SetForwarding(true)
- // Route all packets to address 3 to NIC 2.
- {
- subnet, err := tcpip.NewSubnet("\x03", "\xff")
- if err != nil {
- t.Fatal(err)
- }
- s.SetRouteTable([]tcpip.Route{{Destination: subnet, Gateway: "\x00", NIC: 2}})
- }
+ ep1 := channel.New(10, defaultMTU, "")
+ if err := s.CreateNIC(nicID1, ep1); err != nil {
+ t.Fatalf("CreateNIC(%d, _): %s", nicID1, err)
+ }
+ if err := s.AddAddress(nicID1, fakeNetNumber, "\x01"); err != nil {
+ t.Fatalf("AddAddress(%d, %d, 0x01): %s", nicID1, fakeNetNumber, err)
+ }
- // Send a packet to address 3.
- buf := buffer.NewView(30)
- buf[0] = 3
- ep1.InjectInbound(fakeNetNumber, tcpip.PacketBuffer{
- Data: buf.ToVectorisedView(),
- })
+ ep2 := channelLinkWithHeaderLength{
+ Endpoint: channel.New(10, defaultMTU, ""),
+ headerLength: test.headerLen,
+ }
+ if err := s.CreateNIC(nicID2, &ep2); err != nil {
+ t.Fatalf("CreateNIC(%d, _): %s", nicID2, err)
+ }
+ if err := s.AddAddress(nicID2, fakeNetNumber, "\x02"); err != nil {
+ t.Fatalf("AddAddress(%d, %d, 0x02): %s", nicID2, fakeNetNumber, err)
+ }
- if _, ok := ep2.Read(); !ok {
- t.Fatal("Packet not forwarded")
- }
+ // Route all packets to dstAddr to NIC 2.
+ {
+ subnet, err := tcpip.NewSubnet(dstAddr, "\xff")
+ if err != nil {
+ t.Fatal(err)
+ }
+ s.SetRouteTable([]tcpip.Route{{Destination: subnet, Gateway: "\x00", NIC: nicID2}})
+ }
- // Test that forwarding increments Tx stats correctly.
- if got, want := s.NICInfo()[2].Stats.Tx.Packets.Value(), uint64(1); got != want {
- t.Errorf("got Tx.Packets.Value() = %d, want = %d", got, want)
- }
+ // Send a packet to dstAddr.
+ buf := buffer.NewView(30)
+ buf[0] = dstAddr[0]
+ ep1.InjectInbound(fakeNetNumber, tcpip.PacketBuffer{
+ Data: buf.ToVectorisedView(),
+ })
- if got, want := s.NICInfo()[2].Stats.Tx.Bytes.Value(), uint64(len(buf)); got != want {
- t.Errorf("got Tx.Bytes.Value() = %d, want = %d", got, want)
+ pkt, ok := ep2.Read()
+ if !ok {
+ t.Fatal("packet not forwarded")
+ }
+
+ // Test that the link's MaxHeaderLength is honoured.
+ if capacity, want := pkt.Pkt.Header.AvailableLength(), int(test.headerLen); capacity != want {
+ t.Errorf("got Header.AvailableLength() = %d, want = %d", capacity, want)
+ }
+
+ // Test that forwarding increments Tx stats correctly.
+ if got, want := s.NICInfo()[nicID2].Stats.Tx.Packets.Value(), uint64(1); got != want {
+ t.Errorf("got Tx.Packets.Value() = %d, want = %d", got, want)
+ }
+
+ if got, want := s.NICInfo()[nicID2].Stats.Tx.Bytes.Value(), uint64(len(buf)); got != want {
+ t.Errorf("got Tx.Bytes.Value() = %d, want = %d", got, want)
+ }
+ })
}
}
diff --git a/pkg/tcpip/stack/transport_test.go b/pkg/tcpip/stack/transport_test.go
index 5d1da2f8b..3609a25b6 100644
--- a/pkg/tcpip/stack/transport_test.go
+++ b/pkg/tcpip/stack/transport_test.go
@@ -641,10 +641,10 @@ func TestTransportForwarding(t *testing.T) {
t.Fatal("Response packet not forwarded")
}
- if dst := p.Pkt.Header.View()[0]; dst != 3 {
+ if dst := p.Pkt.Data.First()[0]; dst != 3 {
t.Errorf("Response packet has incorrect destination addresss: got = %d, want = 3", dst)
}
- if src := p.Pkt.Header.View()[1]; src != 1 {
+ if src := p.Pkt.Data.First()[1]; src != 1 {
t.Errorf("Response packet has incorrect source addresss: got = %d, want = 3", src)
}
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-19 16:51:20 +0000