## Proposed Changes
Implement the consensus changes necessary for the upcoming Altair hard fork.
## Additional Info
This is quite a heavy refactor, with pivotal types like the `BeaconState` and `BeaconBlock` changing from structs to enums. This ripples through the whole codebase with field accesses changing to methods, e.g. `state.slot` => `state.slot()`.
Co-authored-by: realbigsean <seananderson33@gmail.com>
## Issue Addressed
NA
## Proposed Changes
As per #2100, uses derives from the sturm library to implement AsRef<str> and AsStaticRef to easily get str values from enums without creating new Strings. Furthermore unifies all attestation error counter into one IntCounterVec vector.
These works are originally by @blacktemplar, I've just created this PR so I can resolve some merge conflicts.
## Additional Info
NA
Co-authored-by: blacktemplar <blacktemplar@a1.net>
## Issue Addressed
Related to #1891, The error is not in the spec yet (see ethereum/eth2.0-specs#2131)
## Proposed Changes
Implement the proposed error, banning peers that send it
## Additional Info
NA
## Issue Addressed
NA
## Proposed Changes
This was mostly done to find the reason why LH was dropping peers from Nimbus. It proved to be useful so I think it's worth it. But there is also some functional stuff here
- Add metrics for rpc errors per client, error type and direction
- Add metrics for downscoring events per source type, client and penalty type
- Add metrics for gossip validation results per client for non-accepted messages
- Make the RPC handler return errors and requests/responses in the order we see them
- Allow a small burst for the Ping rate limit, from 1 every 5 seconds to 2 every 10 seconds
- Send rate limiting errors with a particular code and use that same code to identify them. I picked something different to 128 since that is most likely what other clients are using for their own errors
- Remove some unused code in the `PeerAction` and the rpc handler
- Remove the unused variant `RateLimited`. tTis was never produced directly, since the only way to get the request's protocol is via de handler. The handler upon receiving from LH a response with an error (rate limited in this case) emits this event with the missing info (It was always like this, just pointing out that we do downscore rate limiting errors regardless of the change)
Metrics for Nimbus looked like this:
Downscoring events: `increase(libp2p_peer_actions_per_client{client="Nimbus"}[5m])`

RPC Errors: `increase(libp2p_rpc_errors_per_client{client="Nimbus"}[5m])`

Unaccepted gossip message: `increase(gossipsub_unaccepted_messages_per_client{client="Nimbus"}[5m])`

## Issue Addressed
Following slog's documentation, this should help a bit with string allocations. I left it run for two days and mem usage is lower. This is of course anecdotal, but shouldn't harm anyway
## Proposed Changes
remove `String` creation in logs when possible
## Issue Addressed
- RPC Errors were being logged twice: first in the peer manager and then again in the router, so leave just the peer manager's one
- The "reduce peer count" warn message gets thrown to the user for every missed chunk, so instead print it when the request times out and also do not include there info that is not relevant to the user
- The processor didn't have the service tag so add it
- Impl `KV` for status message
- Do not downscore peers if we are the ones that timed out
Other small improvements
## Issue Addressed
N/A
## Proposed Changes
This PR limits the length of the stream received by the snappy decoder to be the maximum allowed size for the received rpc message type. Also adds further checks to ensure that the length specified in the rpc [encoding-dependent header](https://github.com/ethereum/eth2.0-specs/blob/dev/specs/phase0/p2p-interface.md#encoding-strategies) is within the bounds for the rpc message type being decoded.
## Issue Addressed
#1421
## Proposed Changes
Bounding the error_message that can be returned for RPC domain errors
Co-authored-by: Age Manning <Age@AgeManning.com>
## Issue Addressed
#1056
## Proposed Changes
- Add a rate limiter to the RPC behaviour. This also means the rate limiting occurs just before the door to the application level, so the number of connections a peer opens does not affect this (this would happen in the future if put on the handler)
- The algorithm used is the leaky bucket as a meter / token bucket implemented the GCRA way
- Each protocol has its own limit. Due to the way the algorithm works, the "small" protocols have a hard limit, while bbrange and bbroot allow [burstiness](https://www.wikiwand.com/en/Burstiness). This is so that a peer can't request hundreds of individual requests expecting only one block in a short period of time, it also allows a peer to send two half size requests instead of one with max if they want to without getting limited, and.. it also allows a peer to request a batch of the maximum size and then send _appropriately spaced_ requests of really small sizes. From what I've seen in sync this is plausible when reaching the target slot.
## Additional Info
Needs to be heavily tested
## Issue Addressed
#1112
The logic is slightly different but still valid wrt to error handling.
- Inbound state is either Busy with a future that return the subtream (and info about the processing)
- The state machine works as follows:
- `Idle` with pending responses => `Busy`
- `Busy` => finished ? if so and there are new pending responses then `Busy`, if not then `Idle`
=> not finished remains `Busy`
- Add an `InboundInfo` for readability
- Other stuff:
- Close inbound substreams when all expected responses are sent
- Remove the error variants from `RPCCodedResponse` and use the codes instead
- Fix various spelling mistakes because I got sloppy last time
Sorry for the delay
Co-authored-by: Age Manning <Age@AgeManning.com>