From c1a6ba06ab402c08e3300abd9403026c690dc168 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Thu, 22 Oct 2020 17:00:40 -0700 Subject: Pass NetworkInterface to LinkAddressRequest Previously a link endpoint was passed to stack.LinkAddressResolver.LinkAddressRequest. With this change, implementations that want a route for the link address request may find one through the stack. Other implementations that want to send a packet without a route may continue to do so using the network interface directly. Test: - arp_test.TestLinkAddressRequest - ipv6.TestLinkAddressRequest PiperOrigin-RevId: 338577474 --- pkg/tcpip/network/arp/arp.go | 63 ++++++++++++++++++++++--------------- pkg/tcpip/network/arp/arp_test.go | 32 ++++++++++++++++++- pkg/tcpip/network/ip_test.go | 4 +++ pkg/tcpip/network/ipv6/icmp.go | 52 ++++++++++++++---------------- pkg/tcpip/network/ipv6/icmp_test.go | 35 +++++++++++++++------ 5 files changed, 121 insertions(+), 65 deletions(-) (limited to 'pkg/tcpip/network') diff --git a/pkg/tcpip/network/arp/arp.go b/pkg/tcpip/network/arp/arp.go index 7df77c66e..d8174e8f7 100644 --- a/pkg/tcpip/network/arp/arp.go +++ b/pkg/tcpip/network/arp/arp.go @@ -18,6 +18,7 @@ package arp import ( + "fmt" "sync/atomic" "gvisor.dev/gvisor/pkg/tcpip" @@ -153,25 +154,33 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { e.nud.HandleProbe(remoteAddr, localAddr, ProtocolNumber, remoteLinkAddr, e.protocol) } - // As per RFC 826, under Packet Reception: - // Swap hardware and protocol fields, putting the local hardware and - // protocol addresses in the sender fields. - // - // Send the packet to the (new) target hardware address on the same - // hardware on which the request was received. - origSender := h.HardwareAddressSender() - r.RemoteLinkAddress = tcpip.LinkAddress(origSender) respPkt := stack.NewPacketBuffer(stack.PacketBufferOptions{ ReserveHeaderBytes: int(e.nic.MaxHeaderLength()) + header.ARPSize, }) packet := header.ARP(respPkt.NetworkHeader().Push(header.ARPSize)) packet.SetIPv4OverEthernet() packet.SetOp(header.ARPReply) - copy(packet.HardwareAddressSender(), r.LocalLinkAddress[:]) - copy(packet.ProtocolAddressSender(), h.ProtocolAddressTarget()) - copy(packet.HardwareAddressTarget(), origSender) - copy(packet.ProtocolAddressTarget(), h.ProtocolAddressSender()) - _ = e.nic.WritePacket(r, nil /* gso */, ProtocolNumber, respPkt) + // TODO(gvisor.dev/issue/4582): check copied length once TAP devices have a + // link address. + _ = copy(packet.HardwareAddressSender(), e.nic.LinkAddress()) + if n := copy(packet.ProtocolAddressSender(), h.ProtocolAddressTarget()); n != header.IPv4AddressSize { + panic(fmt.Sprintf("copied %d bytes, expected %d bytes", n, header.IPv4AddressSize)) + } + origSender := h.HardwareAddressSender() + if n := copy(packet.HardwareAddressTarget(), origSender); n != header.EthernetAddressSize { + panic(fmt.Sprintf("copied %d bytes, expected %d bytes", n, header.EthernetAddressSize)) + } + if n := copy(packet.ProtocolAddressTarget(), h.ProtocolAddressSender()); n != header.IPv4AddressSize { + panic(fmt.Sprintf("copied %d bytes, expected %d bytes", n, header.IPv4AddressSize)) + } + + // As per RFC 826, under Packet Reception: + // Swap hardware and protocol fields, putting the local hardware and + // protocol addresses in the sender fields. + // + // Send the packet to the (new) target hardware address on the same + // hardware on which the request was received. + _ = e.nic.WritePacketToRemote(tcpip.LinkAddress(origSender), nil /* gso */, ProtocolNumber, respPkt) case header.ARPReply: addr := tcpip.Address(h.ProtocolAddressSender()) @@ -227,26 +236,28 @@ func (*protocol) LinkAddressProtocol() tcpip.NetworkProtocolNumber { } // LinkAddressRequest implements stack.LinkAddressResolver.LinkAddressRequest. -func (*protocol) LinkAddressRequest(addr, localAddr tcpip.Address, remoteLinkAddr tcpip.LinkAddress, linkEP stack.LinkEndpoint) *tcpip.Error { - r := &stack.Route{ - NetProto: ProtocolNumber, - RemoteLinkAddress: remoteLinkAddr, - } - if len(r.RemoteLinkAddress) == 0 { - r.RemoteLinkAddress = header.EthernetBroadcastAddress +func (*protocol) LinkAddressRequest(targetAddr, localAddr tcpip.Address, remoteLinkAddr tcpip.LinkAddress, nic stack.NetworkInterface) *tcpip.Error { + if len(remoteLinkAddr) == 0 { + remoteLinkAddr = header.EthernetBroadcastAddress } pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{ - ReserveHeaderBytes: int(linkEP.MaxHeaderLength()) + header.ARPSize, + ReserveHeaderBytes: int(nic.MaxHeaderLength()) + header.ARPSize, }) h := header.ARP(pkt.NetworkHeader().Push(header.ARPSize)) + pkt.NetworkProtocolNumber = ProtocolNumber h.SetIPv4OverEthernet() h.SetOp(header.ARPRequest) - copy(h.HardwareAddressSender(), linkEP.LinkAddress()) - copy(h.ProtocolAddressSender(), localAddr) - copy(h.ProtocolAddressTarget(), addr) - - return linkEP.WritePacket(r, nil /* gso */, ProtocolNumber, pkt) + // TODO(gvisor.dev/issue/4582): check copied length once TAP devices have a + // link address. + _ = copy(h.HardwareAddressSender(), nic.LinkAddress()) + if n := copy(h.ProtocolAddressSender(), localAddr); n != header.IPv4AddressSize { + panic(fmt.Sprintf("copied %d bytes, expected %d bytes", n, header.IPv4AddressSize)) + } + if n := copy(h.ProtocolAddressTarget(), targetAddr); n != header.IPv4AddressSize { + panic(fmt.Sprintf("copied %d bytes, expected %d bytes", n, header.IPv4AddressSize)) + } + return nic.WritePacketToRemote(remoteLinkAddr, nil /* gso */, ProtocolNumber, pkt) } // ResolveStaticAddress implements stack.LinkAddressResolver.ResolveStaticAddress. diff --git a/pkg/tcpip/network/arp/arp_test.go b/pkg/tcpip/network/arp/arp_test.go index 626af975a..870c50238 100644 --- a/pkg/tcpip/network/arp/arp_test.go +++ b/pkg/tcpip/network/arp/arp_test.go @@ -423,6 +423,36 @@ func TestDirectRequestWithNeighborCache(t *testing.T) { } } +var _ stack.NetworkInterface = (*testInterface)(nil) + +type testInterface struct { + stack.LinkEndpoint +} + +func (*testInterface) ID() tcpip.NICID { + return 1 +} + +func (*testInterface) IsLoopback() bool { + return false +} + +func (*testInterface) Name() string { + return "" +} + +func (*testInterface) Enabled() bool { + return true +} + +func (t *testInterface) WritePacketToRemote(remoteLinkAddr tcpip.LinkAddress, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) *tcpip.Error { + r := stack.Route{ + NetProto: protocol, + RemoteLinkAddress: remoteLinkAddr, + } + return t.LinkEndpoint.WritePacket(&r, gso, protocol, pkt) +} + func TestLinkAddressRequest(t *testing.T) { tests := []struct { name string @@ -449,7 +479,7 @@ func TestLinkAddressRequest(t *testing.T) { } linkEP := channel.New(defaultChannelSize, defaultMTU, stackLinkAddr) - if err := linkRes.LinkAddressRequest(stackAddr, remoteAddr, test.remoteLinkAddr, linkEP); err != nil { + if err := linkRes.LinkAddressRequest(stackAddr, remoteAddr, test.remoteLinkAddr, &testInterface{LinkEndpoint: linkEP}); err != nil { t.Errorf("got p.LinkAddressRequest(%s, %s, %s, _) = %s", stackAddr, remoteAddr, test.remoteLinkAddr, err) } diff --git a/pkg/tcpip/network/ip_test.go b/pkg/tcpip/network/ip_test.go index f20b94d97..5cc60b98b 100644 --- a/pkg/tcpip/network/ip_test.go +++ b/pkg/tcpip/network/ip_test.go @@ -304,6 +304,10 @@ func (t *testInterface) setEnabled(v bool) { t.mu.disabled = !v } +func (*testInterface) WritePacketToRemote(tcpip.LinkAddress, *stack.GSO, tcpip.NetworkProtocolNumber, *stack.PacketBuffer) *tcpip.Error { + return tcpip.ErrNotSupported +} + func TestSourceAddressValidation(t *testing.T) { rxIPv4ICMP := func(e *channel.Endpoint, src tcpip.Address) { totalLen := header.IPv4MinimumSize + header.ICMPv4MinimumSize diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go index 40908ddaa..fa6c3787b 100644 --- a/pkg/tcpip/network/ipv6/icmp.go +++ b/pkg/tcpip/network/ipv6/icmp.go @@ -651,52 +651,46 @@ func (*protocol) LinkAddressProtocol() tcpip.NetworkProtocolNumber { } // LinkAddressRequest implements stack.LinkAddressResolver. -func (*protocol) LinkAddressRequest(addr, localAddr tcpip.Address, remoteLinkAddr tcpip.LinkAddress, linkEP stack.LinkEndpoint) *tcpip.Error { - // TODO(b/148672031): Use stack.FindRoute instead of manually creating the - // route here. Note, we would need the nicID to do this properly so the right - // NIC (associated to linkEP) is used to send the NDP NS message. - r := stack.Route{ - LocalAddress: localAddr, - RemoteAddress: addr, - LocalLinkAddress: linkEP.LinkAddress(), - RemoteLinkAddress: remoteLinkAddr, +func (p *protocol) LinkAddressRequest(targetAddr, localAddr tcpip.Address, remoteLinkAddr tcpip.LinkAddress, nic stack.NetworkInterface) *tcpip.Error { + remoteAddr := targetAddr + if len(remoteLinkAddr) == 0 { + remoteAddr = header.SolicitedNodeAddr(targetAddr) + remoteLinkAddr = header.EthernetAddressFromMulticastIPv6Address(remoteAddr) } - // If a remote address is not already known, then send a multicast - // solicitation since multicast addresses have a static mapping to link - // addresses. - if len(r.RemoteLinkAddress) == 0 { - r.RemoteAddress = header.SolicitedNodeAddr(addr) - r.RemoteLinkAddress = header.EthernetAddressFromMulticastIPv6Address(r.RemoteAddress) + r, err := p.stack.FindRoute(nic.ID(), localAddr, remoteAddr, ProtocolNumber, false /* multicastLoop */) + if err != nil { + return err } + defer r.Release() + r.ResolveWith(remoteLinkAddr) optsSerializer := header.NDPOptionsSerializer{ - header.NDPSourceLinkLayerAddressOption(linkEP.LinkAddress()), + header.NDPSourceLinkLayerAddressOption(nic.LinkAddress()), } neighborSolicitSize := header.ICMPv6NeighborSolicitMinimumSize + optsSerializer.Length() pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{ - ReserveHeaderBytes: int(linkEP.MaxHeaderLength()) + header.IPv6MinimumSize + neighborSolicitSize, + ReserveHeaderBytes: int(r.MaxHeaderLength()) + neighborSolicitSize, }) pkt.TransportProtocolNumber = header.ICMPv6ProtocolNumber packet := header.ICMPv6(pkt.TransportHeader().Push(neighborSolicitSize)) packet.SetType(header.ICMPv6NeighborSolicit) ns := header.NDPNeighborSolicit(packet.NDPPayload()) - ns.SetTargetAddress(addr) + ns.SetTargetAddress(targetAddr) ns.Options().Serialize(optsSerializer) packet.SetChecksum(header.ICMPv6Checksum(packet, r.LocalAddress, r.RemoteAddress, buffer.VectorisedView{})) - length := uint16(pkt.Size()) - ip := header.IPv6(pkt.NetworkHeader().Push(header.IPv6MinimumSize)) - ip.Encode(&header.IPv6Fields{ - PayloadLength: length, - NextHeader: uint8(header.ICMPv6ProtocolNumber), - HopLimit: header.NDPHopLimit, - SrcAddr: r.LocalAddress, - DstAddr: r.RemoteAddress, - }) + stat := p.stack.Stats().ICMP.V6PacketsSent + if err := r.WritePacket(nil /* gso */, stack.NetworkHeaderParams{ + Protocol: header.ICMPv6ProtocolNumber, + TTL: header.NDPHopLimit, + }, pkt); err != nil { + stat.Dropped.Increment() + return err + } - // TODO(stijlist): count this in ICMP stats. - return linkEP.WritePacket(&r, nil /* gso */, ProtocolNumber, pkt) + stat.NeighborSolicit.Increment() + return nil } // ResolveStaticAddress implements stack.LinkAddressResolver. diff --git a/pkg/tcpip/network/ipv6/icmp_test.go b/pkg/tcpip/network/ipv6/icmp_test.go index 8dc33c560..3b4583b64 100644 --- a/pkg/tcpip/network/ipv6/icmp_test.go +++ b/pkg/tcpip/network/ipv6/icmp_test.go @@ -122,17 +122,13 @@ func (*stubNUDHandler) HandleUpperLevelConfirmation(addr tcpip.Address) { var _ stack.NetworkInterface = (*testInterface)(nil) type testInterface struct { - stack.NetworkLinkEndpoint - - linkAddr tcpip.LinkAddress -} + stack.LinkEndpoint -func (i *testInterface) LinkAddress() tcpip.LinkAddress { - return i.linkAddr + nicID tcpip.NICID } func (*testInterface) ID() tcpip.NICID { - return 0 + return nicID } func (*testInterface) IsLoopback() bool { @@ -147,6 +143,14 @@ func (*testInterface) Enabled() bool { return true } +func (t *testInterface) WritePacketToRemote(remoteLinkAddr tcpip.LinkAddress, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) *tcpip.Error { + r := stack.Route{ + NetProto: protocol, + RemoteLinkAddress: remoteLinkAddr, + } + return t.LinkEndpoint.WritePacket(&r, gso, protocol, pkt) +} + func TestICMPCounts(t *testing.T) { tests := []struct { name string @@ -1235,6 +1239,8 @@ func TestICMPChecksumValidationWithPayloadMultipleViews(t *testing.T) { } func TestLinkAddressRequest(t *testing.T) { + const nicID = 1 + snaddr := header.SolicitedNodeAddr(lladdr0) mcaddr := header.EthernetAddressFromMulticastIPv6Address(snaddr) @@ -1269,7 +1275,18 @@ func TestLinkAddressRequest(t *testing.T) { } linkEP := channel.New(defaultChannelSize, defaultMTU, linkAddr0) - if err := linkRes.LinkAddressRequest(lladdr0, lladdr1, test.remoteLinkAddr, linkEP); err != nil { + if err := s.CreateNIC(nicID, linkEP); err != nil { + t.Fatalf("s.CreateNIC(%d, _): %s", nicID, err) + } + if err := s.AddAddress(nicID, ProtocolNumber, lladdr1); err != nil { + t.Fatalf("s.AddAddress(%d, %d, %s): %s", nicID, ProtocolNumber, lladdr1, err) + } + + // We pass a test network interface to LinkAddressRequest with the same NIC + // ID and link endpoint used by the NIC we created earlier so that we can + // mock a link address request and observe the packets sent to the link + // endpoint even though the stack uses the real NIC. + if err := linkRes.LinkAddressRequest(lladdr0, lladdr1, test.remoteLinkAddr, &testInterface{LinkEndpoint: linkEP, nicID: nicID}); err != nil { t.Errorf("got p.LinkAddressRequest(%s, %s, %s, _) = %s", lladdr0, lladdr1, test.remoteLinkAddr, err) } @@ -1698,7 +1715,7 @@ func TestCallsToNeighborCache(t *testing.T) { t.Fatalf("cannot find protocol instance for network protocol %d", ProtocolNumber) } nudHandler := &stubNUDHandler{} - ep := netProto.NewEndpoint(&testInterface{linkAddr: linkAddr0}, &stubLinkAddressCache{}, nudHandler, &stubDispatcher{}) + ep := netProto.NewEndpoint(&testInterface{LinkEndpoint: channel.New(0, header.IPv6MinimumMTU, linkAddr0)}, &stubLinkAddressCache{}, nudHandler, &stubDispatcher{}) defer ep.Close() if err := ep.Enable(); err != nil { -- cgit v1.2.3