diff options
Diffstat (limited to 'pkg/tcpip/network/arp/arp.go')
| -rw-r--r-- | pkg/tcpip/network/arp/arp.go | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/pkg/tcpip/network/arp/arp.go b/pkg/tcpip/network/arp/arp.go index b47a7be51..7df77c66e 100644 --- a/pkg/tcpip/network/arp/arp.go +++ b/pkg/tcpip/network/arp/arp.go @@ -49,7 +49,6 @@ type endpoint struct { enabled uint32 nic stack.NetworkInterface - linkEP stack.LinkEndpoint linkAddrCache stack.LinkAddressCache nud stack.NUDHandler } @@ -92,12 +91,12 @@ func (e *endpoint) DefaultTTL() uint8 { } func (e *endpoint) MTU() uint32 { - lmtu := e.linkEP.MTU() + lmtu := e.nic.MTU() return lmtu - uint32(e.MaxHeaderLength()) } func (e *endpoint) MaxHeaderLength() uint16 { - return e.linkEP.MaxHeaderLength() + header.ARPSize + return e.nic.MaxHeaderLength() + header.ARPSize } func (e *endpoint) Close() { @@ -154,17 +153,25 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { e.nud.HandleProbe(remoteAddr, localAddr, ProtocolNumber, remoteLinkAddr, e.protocol) } - pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{ - ReserveHeaderBytes: int(e.linkEP.MaxHeaderLength()) + header.ARPSize, + // 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(pkt.NetworkHeader().Push(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(), h.HardwareAddressSender()) + copy(packet.HardwareAddressTarget(), origSender) copy(packet.ProtocolAddressTarget(), h.ProtocolAddressSender()) - _ = e.linkEP.WritePacket(r, nil /* gso */, ProtocolNumber, pkt) + _ = e.nic.WritePacket(r, nil /* gso */, ProtocolNumber, respPkt) case header.ARPReply: addr := tcpip.Address(h.ProtocolAddressSender()) @@ -207,7 +214,6 @@ func (p *protocol) NewEndpoint(nic stack.NetworkInterface, linkAddrCache stack.L e := &endpoint{ protocol: p, nic: nic, - linkEP: nic.LinkEndpoint(), linkAddrCache: linkAddrCache, nud: nud, } @@ -223,6 +229,7 @@ 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 { |