Gossipsub - Implement message sizes per topic

[AgeManning]

Description

The exact message size on gossipsub has become a hot-topic in Ethereum recently. Specific objects are specified to have exact sizes which put upper bounds on the gossipsub message sizes.

Although, gossipsub protobuf messages can incorporate control messages, the upper bound should be bound based on a single maximum message size. It prevents us from downloading too large junk messages only to reject them.

For some topics, the maximum message sizes can change. It might be nice to reduce spam on some topics when there is a large disparity between message sizes per topic.

Motivation

We can reject messages and reduce DOS attack vectors when there is a large message-size disparity across topics.

Requirements

Implement a trait/object/configuration that allows the user to configue a mapping TopicHash -> usize to define the max size per topic.

Open questions

No response

Are you planning to do it yourself in a pull request ?

Maybe