add validation of allowed CrdsValues in gossip

[alexpyattaev]

Protocol enum variants can now be pruned better in Sanitize impl

Problem

Sanitize implementation allowed certain invalid PullRequest variants to travel through the code

Summary of Changes

• Expand Sanitize impl to eliminate values that should not be present in valid traffic.

[gregcusack]

i know its just a draft pr rn. big question is if we can actually get rid of LegacyVersion

[behzadnouri]

This can amplify traffic if someone pushes LegacyVersion to the cluster.
Your node sends pull requests out, other nodes respond with LegacyVersions that you are missing (because they don't drop them yet), then your node drops all LegacyVersions received immediately. Next pull request, same thing happens again.

So your node keeps receiving same LegacyVersion in pull responses repeatedly and drops them every time.

We need to wait for #3653 to hit mainnet, so that nodes do not return deprecated values in pull responses.
Once the cluster has upgraded to #3653 we can drop all deprecated values during deserializiation or sanity checks.

[alexpyattaev]

We need to wait for #3653 to hit mainnet, so that nodes do not return deprecated values in pull responses. Once the cluster has upgraded to #3653 we can drop all deprecated values during deserializiation or sanity checks.

So we allow it in PullResponses for now, got it. Fixed in 814abfa

[behzadnouri]

We need to wait for #3653 to hit mainnet, so that nodes do not return deprecated values in pull responses. Once the cluster has upgraded to #3653 we can drop all deprecated values during deserializiation or sanity checks.

So we allow it in PullResponses for now, got it. Fixed in 814abfa

We need to allow it for push messages as well.
Otherwise you receive the push message, and you drop it.
So your crds table misses that entry, and you will receive an extra pull response next time around you send the pull request; even though you had already received the message from push before (but you dropped it).
If someone spams with LegacyVersion, this can double the traffic.

[alexpyattaev]

We need to wait for #3653 to hit mainnet, so that nodes do not return deprecated values in pull responses. Once the cluster has upgraded to #3653 we can drop all deprecated values during deserializiation or sanity checks.

So we allow it in PullResponses for now, got it. Fixed in 814abfa

We need to allow it for push messages as well.

Done in e4fc336, also added comment so others do not forget about this caveat.

[behzadnouri]

PushMessage instead of "PullMessage"

[alexpyattaev]

oops... corrected.