This is a pure refactor commit.

This commit enables the caller of ProcessNewBlock to access the final
BlockValidationState passed around between CheckBlock(), AcceptBlock(),
and BlockChecked() inside ProcessNewBlock(). This is useful because in a
future commit, we will move the BlockChecked() call out of
ProcessNewBlock(), and BlockChecked() still needs to be able to access
the BlockValidationState.

Co-authored-by: John Newbery <[email protected]>
Co-authored-by: Carl Dong <[email protected]>

This is a pure refactor commit.

Since BlockChecked() doesn't actually depend on all of
PeerLogicValidation but just PeerLogicValidation's CConnman, we can make
a standalone, static function that simply has an extra CConnman
parameter and have the non-static version call the static one.

This also means that, in a future commit, when we move the
BlockChecked() call out of ProcessNewBlock(), the caller of
ProcessNewBlock() can call BlockChecked() directly even if they only
have a CConnman.

Co-authored-by: John Newbery <[email protected]>
Co-authored-by: Carl Dong <[email protected]>

…ProcessNewBlock

Net processing now passes a BlockValidationState object into
ProcessNewBlock(). If CheckBlock() or AcceptBlock() fails, then PNB
returns to net processing without calling the (asynchronous)
BlockChecked Validation Interface method. net processing can use the
invalid BlockValidationState returned to punish peers.

CheckBlock() and AcceptBlock() represent the DoS checks on a block (ie
PoW and malleability). Net processing wants to know about those failed
checks immediately and shouldn't have to wait on a callback. Other
validation interface clients don't care about net processing submitting
bogus malleated blocks to validation, so they don't need to be notified
of BlockChecked.

Furthermore, if PNB returns a valid BlockValidationState, we never need
to try to process (non-malleated) copies of the block from other peers.
That makes it much easier to move the best chain activation logic to a
background thread in future work.

Co-authored-by: John Newbery <[email protected]>
Co-authored-by: Carl Dong <[email protected]>

This is a pure refactor commit.

Co-authored-by: John Newbery <[email protected]>
Co-authored-by: Carl Dong <[email protected]>

Co-authored-by: John Newbery <[email protected]>
Co-authored-by: Carl Dong <[email protected]>

…ckAsReceived

The previous name was misleading, since we can call the function even
when the block has not been received.

…tion

If a CMPCTBLOCK is in flight from peer A and we then succesfully
reconstruct it during CMPCTBLOCK processing from peer B, we need to
clear the in-flight state for the block from peer A.

We can only do that once we've ensured that the block hasn't been
mutated (otherwise peer B could interfere with our block relay from peer
A by providing a mutated block).

Mutation-checking used to be done indirectly by checking that the block
had been writted to disk by checking the CBlockIndex. Now that
ProcessNewBlock returns a BlockValidationState, we can check that state
directly to determine whether to mark the block as no longer in-flight.