diff options
Diffstat (limited to 'pkg/tcpip/network/arp')
| -rw-r--r-- | pkg/tcpip/network/arp/arp.go | 63 |
1 files changed, 37 insertions, 26 deletions
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. |