Only accept a address from a peer if it is a valid IP address (hyperl…

…edger#6439)

Signed-off-by: Matthew Whitehead <[email protected]>

ethereum/p2p/src/main/java/org/hyperledger/besu/ethereum/p2p/discovery/PeerDiscoveryAgent.java

@@ -293,7 +293,9 @@ protected void handleIncomingPacket(final Endpoint sourceEndpoint, final Packet
             .getPacketData(PingPacketData.class)
             .flatMap(PingPacketData::getFrom)
             .map(Endpoint::getHost)
-            .filter(abc -> !abc.equals("127.0.0.1"))
+            .filter(
+                fromAddr ->
+                    (!fromAddr.equals("127.0.0.1") && InetAddresses.isInetAddress(fromAddr)))
             .stream()
             .peek(
                 h ->