Chain-Sync ingress limits

[coot]

We should use max header size limit which lives on the chain. Currently we set limits for the lifetime of a process, and we'd like to change it to set them when connection starts.

@mrBliss we would like to have a way to access the current max header size.
@dcoutts mentioned that it would be also good check if it is enforced by the
ledger.

[mrBliss]

@mrBliss we would like to have a way to access the current max header size.

Can do. I can add maxHeaderSize :: LedgerState blk -> Word32 to LedgerSupportsMempool. You can get a LedgerState using ChainDB.getCurrentLedger + NodeKernel.getChainDB. Where exactly do you need access to it?

@dcoutts mentioned that it would be also good check if it is enforced by the
ledger.

I would expect so (I know for a fact that it is the case for Shelley, i.e., we call chainChecks). Check with the ledger team for Byron.

[coot]

We will need to access it when we start a connection; passing maxHeaderSizeM :: m Word32 through DiffusionArguments would work. I think the diffusion is run in Ouroboros.Consensus.Node.

[mrBliss]

Now that #2275 is merged, you have maxHeaderSize :: LedgerState blk -> Word32 at your disposal.

[coot]

Great, thanks.