/**
* Generates a route intent for a prefix, the next hop IP address, and the next hop MAC address.
*
* <p>This method will find the egress interface for the intent. Intent will match dst IP prefix
* and rewrite dst MAC address at all other border switches, then forward packets according to dst
* MAC address.
*
* @param prefix IP prefix of the route to add
* @param nextHopIpAddress IP address of the next hop
* @param nextHopMacAddress MAC address of the next hop
* @return the generated intent, or null if no intent should be submitted
*/
private MultiPointToSinglePointIntent generateRouteIntent(
IpPrefix prefix, IpAddress nextHopIpAddress, MacAddress nextHopMacAddress) {
// Find the attachment point (egress interface) of the next hop
Interface egressInterface = interfaceService.getMatchingInterface(nextHopIpAddress);
if (egressInterface == null) {
log.warn("No outgoing interface found for {}", nextHopIpAddress);
return null;
}
// Generate the intent itself
Set<ConnectPoint> ingressPorts = new HashSet<>();
ConnectPoint egressPort = egressInterface.connectPoint();
log.debug("Generating intent for prefix {}, next hop mac {}", prefix, nextHopMacAddress);
for (Interface intf : interfaceService.getInterfaces()) {
// TODO this should be only peering interfaces
if (!intf.connectPoint().equals(egressInterface.connectPoint())) {
ConnectPoint srcPort = intf.connectPoint();
ingressPorts.add(srcPort);
}
}
// Match the destination IP prefix at the first hop
TrafficSelector.Builder selector = DefaultTrafficSelector.builder();
if (prefix.isIp4()) {
selector.matchEthType(Ethernet.TYPE_IPV4);
// if it is default route, then we do not need match destination
// IP address
if (prefix.prefixLength() != 0) {
selector.matchIPDst(prefix);
}
} else {
selector.matchEthType(Ethernet.TYPE_IPV6);
// if it is default route, then we do not need match destination
// IP address
if (prefix.prefixLength() != 0) {
selector.matchIPv6Dst(prefix);
}
}
// Rewrite the destination MAC address
TrafficTreatment.Builder treatment =
DefaultTrafficTreatment.builder().setEthDst(nextHopMacAddress);
if (!egressInterface.vlan().equals(VlanId.NONE)) {
treatment.setVlanId(egressInterface.vlan());
// If we set VLAN ID, we have to make sure a VLAN tag exists.
// TODO support no VLAN -> VLAN routing
selector.matchVlanId(VlanId.ANY);
}
int priority = prefix.prefixLength() * PRIORITY_MULTIPLIER + PRIORITY_OFFSET;
Key key = Key.of(prefix.toString(), appId);
return MultiPointToSinglePointIntent.builder()
.appId(appId)
.key(key)
.selector(selector.build())
.treatment(treatment.build())
.ingressPoints(ingressPorts)
.egressPoint(egressPort)
.priority(priority)
.constraints(CONSTRAINTS)
.build();
}
