private void sendArpResponse(ARP arpRequest, MacAddress targetMac, VlanId vlanId) {
ARP arpReply = new ARP();
arpReply
.setHardwareType(ARP.HW_TYPE_ETHERNET)
.setProtocolType(ARP.PROTO_TYPE_IP)
.setHardwareAddressLength((byte) Ethernet.DATALAYER_ADDRESS_LENGTH)
.setProtocolAddressLength((byte) Ip4Address.BYTE_LENGTH)
.setOpCode(ARP.OP_REPLY)
.setSenderHardwareAddress(targetMac.toBytes())
.setSenderProtocolAddress(arpRequest.getTargetProtocolAddress())
.setTargetHardwareAddress(arpRequest.getSenderHardwareAddress())
.setTargetProtocolAddress(arpRequest.getSenderProtocolAddress());
Ethernet eth = new Ethernet();
eth.setDestinationMACAddress(arpRequest.getSenderHardwareAddress())
.setSourceMACAddress(targetMac.toBytes())
.setEtherType(Ethernet.TYPE_ARP)
.setPayload(arpReply);
MacAddress hostMac = MacAddress.valueOf(arpReply.getTargetHardwareAddress());
HostId dstId = HostId.hostId(hostMac, vlanId);
Host dst = srManager.hostService.getHost(dstId);
if (dst == null) {
log.warn("Cannot send ARP response to host {}", dstId);
return;
}
TrafficTreatment treatment =
DefaultTrafficTreatment.builder().setOutput(dst.location().port()).build();
OutboundPacket packet =
new DefaultOutboundPacket(
dst.location().deviceId(), treatment, ByteBuffer.wrap(eth.serialize()));
srManager.packetService.emit(packet);
}
/**
* Processes incoming ARP packets.
*
* <p>If it is an ARP request to router itself or known hosts, then it sends ARP response. If it
* is an ARP request to unknown hosts in its own subnet, then it flood the ARP request to the
* ports. If it is an ARP response, then set a flow rule for the host and forward any IP packets
* to the host in the packet buffer to the host.
*
* <p>Note: We handles all ARP packet in, even for those ARP packets between hosts in the same
* subnet. For an ARP packet with broadcast destination MAC, some switches pipelines will send it
* to the controller due to table miss, other swithches will flood the packets directly in the
* data plane without packet in. We can deal with both cases.
*
* @param pkt incoming packet
*/
public void processPacketIn(InboundPacket pkt) {
Ethernet ethernet = pkt.parsed();
ARP arp = (ARP) ethernet.getPayload();
ConnectPoint connectPoint = pkt.receivedFrom();
PortNumber inPort = connectPoint.port();
DeviceId deviceId = connectPoint.deviceId();
byte[] senderMacAddressByte = arp.getSenderHardwareAddress();
Ip4Address hostIpAddress = Ip4Address.valueOf(arp.getSenderProtocolAddress());
srManager.routingRulePopulator.populateIpRuleForHost(
deviceId, hostIpAddress, MacAddress.valueOf(senderMacAddressByte), inPort);
if (arp.getOpCode() == ARP.OP_REQUEST) {
handleArpRequest(deviceId, connectPoint, ethernet);
} else {
handleArpReply(deviceId, connectPoint, ethernet);
}
}