[VOL-4382] Adding 'AlarmIndication' to MessageType String converter, adding support for ICMP packets in order to avoid false error messages

Change-Id: If48948b0a96a7c87fe62191f880bb5617885d542
diff --git a/internal/bbsim/packetHandlers/filters.go b/internal/bbsim/packetHandlers/filters.go
index a930b1e..5a3a24f 100644
--- a/internal/bbsim/packetHandlers/filters.go
+++ b/internal/bbsim/packetHandlers/filters.go
@@ -44,6 +44,13 @@
 	return false
 }
 
+func IsIcmpPacket(pkt gopacket.Packet) bool {
+	if layer := pkt.Layer(layers.LayerTypeICMPv6); layer != nil {
+		return true
+	}
+	return false
+}
+
 // return true if the packet is coming in the OLT from the DHCP Server
 // given that we only check DHCP packets we can use the Operation
 // Request are outgoing (toward the server)
@@ -90,6 +97,8 @@
 		return DHCP, nil
 	} else if IsIgmpPacket(pkt) {
 		return IGMP, nil
+	} else if IsIcmpPacket(pkt) {
+		return ICMP, nil
 	}
 	return UNKNOWN, errors.New("unknown-packet-type")
 }