## Issue Addressed
Closes#1891Closes#1784
## Proposed Changes
Implement checkpoint sync for Lighthouse, enabling it to start from a weak subjectivity checkpoint.
## Additional Info
- [x] Return unavailable status for out-of-range blocks requested by peers (#2561)
- [x] Implement sync daemon for fetching historical blocks (#2561)
- [x] Verify chain hashes (either in `historical_blocks.rs` or the calling module)
- [x] Consistency check for initial block + state
- [x] Fetch the initial state and block from a beacon node HTTP endpoint
- [x] Don't crash fetching beacon states by slot from the API
- [x] Background service for state reconstruction, triggered by CLI flag or API call.
Considered out of scope for this PR:
- Drop the requirement to provide the `--checkpoint-block` (this would require some pretty heavy refactoring of block verification)
Co-authored-by: Diva M <divma@protonmail.com>
## Issue Addressed
N/A
## Proposed Changes
Add a fork_digest to `ForkContext` only if it is set in the config.
Reject gossip messages on post fork topics before the fork happens.
Edit: Instead of rejecting gossip messages on post fork topics, we now subscribe to post fork topics 2 slots before the fork.
Co-authored-by: Age Manning <Age@AgeManning.com>
## 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
None
## Proposed Changes
* Correct typo in one comment, elaborate some others.
* Add asserts to ensure comments match code.
* Eliminate one unnecessary `clone`.
## Additional Info
None
## 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
N/A
## Proposed Changes
Adds the following check from the spec
> A reader SHOULD NOT read more than max_encoded_len(n) bytes after reading the SSZ length-prefix n from the header.
## 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
#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>
