Dos Attack on the network/rlp level

[mfrankovi]

libp2p library processes the network packets we are receiving and it verifies that the packets are in correct RLP format. We allow receiving very large packets by receiving them in multiple chunks. I am not even sure if we currently impose any limits on the maximum size of the packet we send. This could be a vector for an attack by sending a huge but valid rlp packet which would take a very long time to process within the libp2p library. So this would require some investigation to see if actually there is a threat there. Again it comes down to a problem of defining the max packet size possible. Currently dag and pbft syncing packets can be huge and it is hard to determine max limit for them.