private void transformAndSend(IPv4 ipv4, Interface egressInterface, MacAddress macAddress) {
Ethernet eth = new Ethernet();
eth.setDestinationMACAddress(macAddress);
eth.setSourceMACAddress(egressInterface.mac());
eth.setEtherType(EthType.EtherType.IPV4.ethType().toShort());
eth.setPayload(ipv4);
if (!egressInterface.vlan().equals(VlanId.NONE)) {
eth.setVlanID(egressInterface.vlan().toShort());
}
ipv4.setTtl((byte) (ipv4.getTtl() - 1));
ipv4.setChecksum((short) 0);
send(eth, egressInterface.connectPoint());
}
/**
* Sends an ICMP reply message.
*
* <p>Note: we assume that packets sending from the edge switches to the hosts have untagged VLAN.
*
* @param icmpRequest the original ICMP request
* @param outport the output port where the ICMP reply should be sent to
*/
private void sendICMPResponse(Ethernet icmpRequest, ConnectPoint outport) {
// Note: We assume that packets arrive at the edge switches have
// untagged VLAN.
Ethernet icmpReplyEth = new Ethernet();
IPv4 icmpRequestIpv4 = (IPv4) icmpRequest.getPayload();
IPv4 icmpReplyIpv4 = new IPv4();
int destAddress = icmpRequestIpv4.getDestinationAddress();
icmpReplyIpv4.setDestinationAddress(icmpRequestIpv4.getSourceAddress());
icmpReplyIpv4.setSourceAddress(destAddress);
icmpReplyIpv4.setTtl((byte) 64);
icmpReplyIpv4.setChecksum((short) 0);
ICMP icmpReply = new ICMP();
icmpReply.setPayload(((ICMP) icmpRequestIpv4.getPayload()).getPayload());
icmpReply.setIcmpType(ICMP.TYPE_ECHO_REPLY);
icmpReply.setIcmpCode(ICMP.SUBTYPE_ECHO_REPLY);
icmpReply.setChecksum((short) 0);
icmpReplyIpv4.setPayload(icmpReply);
icmpReplyEth.setPayload(icmpReplyIpv4);
icmpReplyEth.setEtherType(Ethernet.TYPE_IPV4);
icmpReplyEth.setDestinationMACAddress(icmpRequest.getSourceMACAddress());
icmpReplyEth.setSourceMACAddress(icmpRequest.getDestinationMACAddress());
Ip4Address destIpAddress = Ip4Address.valueOf(icmpReplyIpv4.getDestinationAddress());
Ip4Address destRouterAddress = config.getRouterIpAddressForASubnetHost(destIpAddress);
int sid = config.getSegmentId(destRouterAddress);
if (sid < 0) {
log.warn("Cannot find the Segment ID for {}", destAddress);
return;
}
sendPacketOut(outport, icmpReplyEth, sid);
}
