[service] Fix go linter errors

service/firewall/packet_handler.go

@@ -593,18 +593,31 @@ func inspectDNSPacket(conn *network.Connection, pkt packet.Packet) {
 	}
 
 	dnsPacket := new(dns.Msg)
-	pkt.LoadPacketData()
+	err := pkt.LoadPacketData()
+	if err != nil {
+		_ = pkt.Block()
+		log.Errorf("filter: failed to load packet payload: %s", err)
+		return
+	}
 
 	// Parse and block invalid packets.
-	err := dnsPacket.Unpack(pkt.Payload())
+	err = dnsPacket.Unpack(pkt.Payload())
 	if err != nil {
-		pkt.PermanentBlock()
-		conn.SetVerdict(network.VerdictBlock, "none DNS data on DNS port", "", nil)
+		err = pkt.PermanentBlock()
+		if err != nil {
+			log.Errorf("filter: failed to block packet: %s", err)
+		}
+		_ = conn.SetVerdict(network.VerdictBlock, "none DNS data on DNS port", "", nil)
 		conn.VerdictPermanent = true
 		conn.Save()
 		return
 	}
-	pkt.Accept()
+
+	// Packet was parsed, accept the connection and continue.
+	err = pkt.Accept()
+	if err != nil {
+		log.Errorf("filter: failed to accept dns packet: %s", err)
+	}
 
 	conn.Type = network.DNSRequest
 

service/integration/module.go

@@ -10,6 +10,7 @@ type OSIntegration struct {
 	m      *mgr.Manager
 	states *mgr.StateMgr
 
+	//nolint:unused
 	os OSSpecific
 
 	instance instance

service/network/packet/parse.go

@@ -174,6 +174,14 @@ func ParseLayer4(packetData []byte, pktBase *Base) (err error) {
 		layer = layers.LayerTypeUDP
 	case ICMPv6:
 		layer = layers.LayerTypeICMPv6
+	case UDPLite:
+		return fmt.Errorf("UDPLite not supported")
+	case RAW:
+		return fmt.Errorf("RAW protocol not supported")
+	case AnyHostInternalProtocol61:
+		return fmt.Errorf("AnyHostInternalProtocol61 protocol not supported")
+	default:
+		return fmt.Errorf("protocol not supported")
 	}
 
 	packet := gopacket.NewPacket(packetData, layer, gopacket.DecodeOptions{