fqdn: Fix Upgrade Issue Between PortProto Versions

Users of this library need Cilium to both check
restore and updated DNS rules for the new PortProto
version. Otherwise upgrade incompatibilities exist
between Cilium and programs that utilize this library.

Signed-off-by: Nate Sweet <nathanjsweet@pm.me>

pkg/fqdn/dnsproxy/proxy.go

@@ -205,6 +205,11 @@ func (p *DNSProxy) checkRestored(endpointID uint64, destPortProto restore.PortPr
 	if !exists && destPortProto.IsPortV2() {
 		// Check if there is a Version 1 restore.
 		ipRules, exists = p.restored[endpointID][destPortProto.ToV1()]
+		log.WithFields(logrus.Fields{
+			logfields.EndpointID: endpointID,
+			logfields.Port:       destPortProto.Port(),
+			logfields.Protocol:   destPortProto.Protocol(),
+		}).Debugf("Checking if restored V1 IP rules (exists: %t) for endpoint: %+v", exists, ipRules)
 		if !exists {
 			return false
 		}
@@ -514,6 +519,14 @@ func (allow perEPAllow) setPortRulesForIDFromUnifiedFormat(cache regexCache, end
 // passed-in endpointID and destPort with setPortRulesForID
 func (allow perEPAllow) getPortRulesForID(endpointID uint64, destPortProto restore.PortProto) (rules CachedSelectorREEntry, exists bool) {
 	rules, exists = allow[endpointID][destPortProto]
+	if !exists && destPortProto.Protocol() != 0 {
+		rules, exists = allow[endpointID][destPortProto.ToV1()]
+		log.WithFields(logrus.Fields{
+			logfields.EndpointID: endpointID,
+			logfields.Port:       destPortProto.Port(),
+			logfields.Protocol:   destPortProto.Protocol(),
+		}).Debugf("Checking for V1 port rule (exists: %t) for endpoint: %+v", exists, rules)
+	}
 	return
 }