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Queue packets in WritePackets when resolving link address 

Test: integration_test.TestWritePacketsLinkResolution

Fixes #4458.

PiperOrigin-RevId: 353108826
This commit is contained in:
Ghanan Gowripalan 2021-01-21 14:51:24 -08:00 committed by gVisor bot
parent 0ca4cf7698
commit 89df5a681c
4 changed files with 222 additions and 25 deletions
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34
pkg/tcpip/link/pipe/pipe.go
View File

@ -45,12 +45,7 @@ type Endpoint struct {
linkAddr tcpip.LinkAddress
}
// WritePacket implements stack.LinkEndpoint.
func (e *Endpoint) WritePacket(r stack.RouteInfo, _ *stack.GSO, proto tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) *tcpip.Error {
if !e.linked.IsAttached() {
return nil
}
func (e *Endpoint) deliverPackets(r stack.RouteInfo, proto tcpip.NetworkProtocolNumber, pkts stack.PacketBufferList) {
// 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
@ -70,16 +65,33 @@ func (e *Endpoint) WritePacket(r stack.RouteInfo, _ *stack.GSO, proto tcpip.Netw
//
// TODO(gvisor.dev/issue/5289): don't use a new goroutine once we support send
// and receive queues.
go e.linked.dispatcher.DeliverNetworkPacket(r.LocalLinkAddress /* remote */, r.RemoteLinkAddress /* local */, proto, stack.NewPacketBuffer(stack.PacketBufferOptions{
Data: buffer.NewVectorisedView(pkt.Size(), pkt.Views()),
}))
go func() {
for pkt := pkts.Front(); pkt != nil; pkt = pkt.Next() {
e.linked.dispatcher.DeliverNetworkPacket(r.LocalLinkAddress /* remote */, r.RemoteLinkAddress /* local */, proto, stack.NewPacketBuffer(stack.PacketBufferOptions{
Data: buffer.NewVectorisedView(pkt.Size(), pkt.Views()),
}))
}
}()
}
// WritePacket implements stack.LinkEndpoint.
func (e *Endpoint) WritePacket(r stack.RouteInfo, _ *stack.GSO, proto tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) *tcpip.Error {
if e.linked.IsAttached() {
var pkts stack.PacketBufferList
pkts.PushBack(pkt)
e.deliverPackets(r, proto, pkts)
}
return nil
}
// WritePackets implements stack.LinkEndpoint.
func (*Endpoint) WritePackets(stack.RouteInfo, *stack.GSO, stack.PacketBufferList, tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
panic("not implemented")
func (e *Endpoint) WritePackets(r stack.RouteInfo, _ *stack.GSO, pkts stack.PacketBufferList, proto tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
if e.linked.IsAttached() {
e.deliverPackets(r, proto, pkts)
}
return pkts.Len(), nil
}
// Attach implements stack.LinkEndpoint.

37
pkg/tcpip/stack/nic.go
View File

@ -358,16 +358,43 @@ func (n *NIC) writePacket(r RouteInfo, gso *GSO, protocol tcpip.NetworkProtocolN
// WritePackets implements NetworkLinkEndpoint.
func (n *NIC) WritePackets(r *Route, gso *GSO, pkts PacketBufferList, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
// TODO(gvisor.dev/issue/4458): Queue packets whie link address resolution
// is being peformed like WritePacket.
routeInfo := r.Fields()
// As per relevant RFCs, we should queue packets while we wait for link
// resolution to complete.
//
// RFC 1122 section 2.3.2.2 (for IPv4):
// The link layer SHOULD save (rather than discard) at least
// one (the latest) packet of each set of packets destined to
// the same unresolved IP address, and transmit the saved
// packet when the address has been resolved.
//
// RFC 4861 section 7.2.2 (for IPv6):
// While waiting for address resolution to complete, the sender MUST, for
// each neighbor, retain a small queue of packets waiting for address
// resolution to complete. The queue MUST hold at least one packet, and MAY
// contain more. However, the number of queued packets per neighbor SHOULD
// be limited to some small value. When a queue overflows, the new arrival
// SHOULD replace the oldest entry. Once address resolution completes, the
// node transmits any queued packets.
if ch, err := r.Resolve(nil); err != nil {
if err == tcpip.ErrWouldBlock {
r.Acquire()
n.linkResQueue.enqueue(ch, r, protocol, &pkts)
return pkts.Len(), nil
}
return 0, err
}
return n.writePackets(r.Fields(), gso, protocol, pkts)
}
func (n *NIC) writePackets(r RouteInfo, gso *GSO, protocol tcpip.NetworkProtocolNumber, pkts PacketBufferList) (int, *tcpip.Error) {
for pkt := pkts.Front(); pkt != nil; pkt = pkt.Next() {
pkt.EgressRoute = routeInfo
pkt.EgressRoute = r
pkt.GSOOptions = gso
pkt.NetworkProtocolNumber = protocol
}
writtenPackets, err := n.LinkEndpoint.WritePackets(routeInfo, gso, pkts, protocol)
writtenPackets, err := n.LinkEndpoint.WritePackets(r, gso, pkts, protocol)
n.stats.Tx.Packets.IncrementBy(uint64(writtenPackets))
writtenBytes := 0
for i, pb := 0, pkts.Front(); i < writtenPackets && pb != nil; i, pb = i+1, pb.Next() {

51
pkg/tcpip/stack/pending_packets.go
View File

@ -28,10 +28,26 @@ const (
maxPendingPacketsPerResolution = 256
)
// pendingPacketBuffer is a pending packet buffer.
//
// TODO(gvisor.dev/issue/5331): Drop this when we drop WritePacket and only use
// WritePackets so we can use a PacketBufferList everywhere.
type pendingPacketBuffer interface {
len() int
}
func (*PacketBuffer) len() int {
return 1
}
func (p *PacketBufferList) len() int {
return p.Len()
}
type pendingPacket struct {
route *Route
proto tcpip.NetworkProtocolNumber
pkt *PacketBuffer
pkt pendingPacketBuffer
}
// packetsPendingLinkResolution is a queue of packets pending link resolution.
@ -54,16 +70,17 @@ func (f *packetsPendingLinkResolution) init() {
f.packets = make(map[<-chan struct{}][]pendingPacket)
}
func incrementOutgoingPacketErrors(r *Route, proto tcpip.NetworkProtocolNumber) {
r.Stats().IP.OutgoingPacketErrors.Increment()
func incrementOutgoingPacketErrors(r *Route, proto tcpip.NetworkProtocolNumber, pkt pendingPacketBuffer) {
n := uint64(pkt.len())
r.Stats().IP.OutgoingPacketErrors.IncrementBy(n)
// ok may be false if the endpoint's stats do not collect IP-related data.
if ipEndpointStats, ok := r.outgoingNIC.getNetworkEndpoint(proto).Stats().(IPNetworkEndpointStats); ok {
ipEndpointStats.IPStats().OutgoingPacketErrors.Increment()
ipEndpointStats.IPStats().OutgoingPacketErrors.IncrementBy(n)
}
}
func (f *packetsPendingLinkResolution) enqueue(ch <-chan struct{}, r *Route, proto tcpip.NetworkProtocolNumber, pkt *PacketBuffer) {
func (f *packetsPendingLinkResolution) enqueue(ch <-chan struct{}, r *Route, proto tcpip.NetworkProtocolNumber, pkt pendingPacketBuffer) {
f.Lock()
defer f.Unlock()
@ -73,7 +90,7 @@ func (f *packetsPendingLinkResolution) enqueue(ch <-chan struct{}, r *Route, pro
packets[0] = pendingPacket{}
packets = packets[1:]
incrementOutgoingPacketErrors(r, proto)
incrementOutgoingPacketErrors(r, proto, p.pkt)
p.route.Release()
}
@ -113,13 +130,29 @@ func (f *packetsPendingLinkResolution) enqueue(ch <-chan struct{}, r *Route, pro
for _, p := range packets {
if cancelled || p.route.IsResolutionRequired() {
incrementOutgoingPacketErrors(r, proto)
incrementOutgoingPacketErrors(r, proto, p.pkt)
if linkResolvableEP, ok := p.route.outgoingNIC.getNetworkEndpoint(p.route.NetProto).(LinkResolvableNetworkEndpoint); ok {
linkResolvableEP.HandleLinkResolutionFailure(pkt)
switch pkt := p.pkt.(type) {
case *PacketBuffer:
linkResolvableEP.HandleLinkResolutionFailure(pkt)
case *PacketBufferList:
for pb := pkt.Front(); pb != nil; pb = pb.Next() {
linkResolvableEP.HandleLinkResolutionFailure(pb)
}
default:
panic(fmt.Sprintf("unrecognized pending packet buffer type = %T", p.pkt))
}
}
} else {
p.route.outgoingNIC.writePacket(p.route.Fields(), nil /* gso */, p.proto, p.pkt)
switch pkt := p.pkt.(type) {
case *PacketBuffer:
p.route.outgoingNIC.writePacket(p.route.Fields(), nil /* gso */, p.proto, pkt)
case *PacketBufferList:
p.route.outgoingNIC.writePackets(p.route.Fields(), nil /* gso */, p.proto, *pkt)
default:
panic(fmt.Sprintf("unrecognized pending packet buffer type = %T", p.pkt))
}
}
p.route.Release()
}

125
pkg/tcpip/tests/integration/link_resolution_test.go
View File

@ -23,6 +23,7 @@ import (
"github.com/google/go-cmp/cmp"
"github.com/google/go-cmp/cmp/cmpopts"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/buffer"
"gvisor.dev/gvisor/pkg/tcpip/checker"
"gvisor.dev/gvisor/pkg/tcpip/header"
"gvisor.dev/gvisor/pkg/tcpip/link/pipe"
@ -32,6 +33,7 @@ import (
"gvisor.dev/gvisor/pkg/tcpip/stack"
"gvisor.dev/gvisor/pkg/tcpip/transport/icmp"
"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
"gvisor.dev/gvisor/pkg/waiter"
)
@ -456,3 +458,126 @@ func TestGetLinkAddress(t *testing.T) {
})
}
}
func TestWritePacketsLinkResolution(t *testing.T) {
const (
host1NICID = 1
host2NICID = 4
)
tests := []struct {
name string
netProto tcpip.NetworkProtocolNumber
remoteAddr tcpip.Address
expectedWriteErr *tcpip.Error
}{
{
name: "IPv4",
netProto: ipv4.ProtocolNumber,
remoteAddr: ipv4Addr2.AddressWithPrefix.Address,
expectedWriteErr: nil,
},
{
name: "IPv6",
netProto: ipv6.ProtocolNumber,
remoteAddr: ipv6Addr2.AddressWithPrefix.Address,
expectedWriteErr: nil,
},
}
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
stackOpts := stack.Options{
NetworkProtocols: []stack.NetworkProtocolFactory{arp.NewProtocol, ipv4.NewProtocol, ipv6.NewProtocol},
TransportProtocols: []stack.TransportProtocolFactory{udp.NewProtocol},
}
host1Stack, host2Stack := setupStack(t, stackOpts, host1NICID, host2NICID)
var serverWQ waiter.Queue
serverWE, serverCH := waiter.NewChannelEntry(nil)
serverWQ.EventRegister(&serverWE, waiter.EventIn)
serverEP, err := host2Stack.NewEndpoint(udp.ProtocolNumber, test.netProto, &serverWQ)
if err != nil {
t.Fatalf("host2Stack.NewEndpoint(%d, %d, _): %s", udp.ProtocolNumber, test.netProto, err)
}
defer serverEP.Close()
serverAddr := tcpip.FullAddress{Port: 1234}
if err := serverEP.Bind(serverAddr); err != nil {
t.Fatalf("serverEP.Bind(%#v): %s", serverAddr, err)
}
r, err := host1Stack.FindRoute(host1NICID, "", test.remoteAddr, test.netProto, false /* multicastLoop */)
if err != nil {
t.Fatalf("host1Stack.FindRoute(%d, '', %s, %d, false): %s", host1NICID, test.remoteAddr, test.netProto, err)
}
defer r.Release()
data := []byte{1, 2}
var pkts stack.PacketBufferList
for _, d := range data {
pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
ReserveHeaderBytes: header.UDPMinimumSize + int(r.MaxHeaderLength()),
Data: buffer.View([]byte{d}).ToVectorisedView(),
})
pkt.TransportProtocolNumber = udp.ProtocolNumber
length := uint16(pkt.Size())
udpHdr := header.UDP(pkt.TransportHeader().Push(header.UDPMinimumSize))
udpHdr.Encode(&header.UDPFields{
SrcPort: 5555,
DstPort: serverAddr.Port,
Length: length,
})
xsum := r.PseudoHeaderChecksum(udp.ProtocolNumber, length)
for _, v := range pkt.Data.Views() {
xsum = header.Checksum(v, xsum)
}
udpHdr.SetChecksum(^udpHdr.CalculateChecksum(xsum))
pkts.PushBack(pkt)
}
params := stack.NetworkHeaderParams{
Protocol: udp.ProtocolNumber,
TTL: 64,
TOS: stack.DefaultTOS,
}
if n, err := r.WritePackets(nil /* gso */, pkts, params); err != nil {
t.Fatalf("r.WritePackets(nil, %#v, _): %s", params, err)
} else if want := pkts.Len(); want != n {
t.Fatalf("got r.WritePackets(nil, %#v, _) = %d, want = %d", n, params, want)
}
var writer bytes.Buffer
count := 0
for {
var rOpts tcpip.ReadOptions
res, err := serverEP.Read(&writer, rOpts)
if err != nil {
if err == tcpip.ErrWouldBlock {
// Should not have anymore bytes to read after we read the sent
// number of bytes.
if count == len(data) {
break
}
<-serverCH
continue
}
t.Fatalf("serverEP.Read(_, %#v): %s", rOpts, err)
}
count += res.Count
}
if got, want := host2Stack.Stats().UDP.PacketsReceived.Value(), uint64(len(data)); got != want {
t.Errorf("got host2Stack.Stats().UDP.PacketsReceived.Value() = %d, want = %d", got, want)
}
if diff := cmp.Diff(data, writer.Bytes()); diff != "" {
t.Errorf("read bytes mismatch (-want +got):\n%s", diff)
}
})
}
}