Introduce a cap to reputation score increase

[fab-10]

Signed-off-by: Fabio Di Fabio fabio.difabio@consensys.net

PR description

#4130 introduced an way to increase reputation in case the peer is doing good, but there is no cap to the reputation score the peer can have.

The log shows peers with very high reputation, for example:

FullSyncTargetManager","message":"Caught up to best peer: PeerId 0xb3e02a84270c590f562e2c8b8274930c54b0a00ae001d44bd790b55c3bbc578c70738e6d4a2d32df78b6cf27a071fe54a068f3192c42ac29bd81a6663fe4fa0f, reputation PeerReputation 561, validated? true, disconnected? false, client: Geth/v1.10.21-stable-67109427/linux-amd64/go1.18.5, connection 1312721736, enode enode://b3e02a84270c590f562e2c8b8274930c54b0a00ae001d44bd790b55c3bbc578c70738e6d4a2d32df78b6cf27a071fe54a068f3192c42ac29bd81a6663fe4fa0f@34.92.61.128:29888, chain state: ChainState{estimatedHeight=7369229, bestBlock=BestBlock{totalDifficulty=0x0000000000000000000000000000000000000000000000000000000000a45b44, blockHash=0xb7c2ba396d3f4561fe619796e7ef399080823161f4b831c5b3f48445e7bf13a1, number=7369228}}. Current peers: 3","throwable":""}

since there is no cap to how much the reputation can increase.

I think make sense to have an upper bound, a peer can increase its repution until it reaches the default max again, otherwise a peer that is good for a long time, and start to be useless, will take a long time before its reputation goes below other more recent good peers

Fixed Issue(s)

Documentation

• I thought about documentation and added the doc-change-required label to this PR if
  updates are required.

Changelog

• I thought about the changelog and included a changelog update if required.

[macfarla]

having an upper limit makes sense. it would make sense though to have the default score less than the max

[macfarla]

LGTM