## Issue Addressed
New lints for rust 1.65
## Proposed Changes
Notable change is the identification or parameters that are only used in recursion
## Additional Info
na
## Proposed Changes
Enable multiple database backends for the slasher, either MDBX (default) or LMDB. The backend can be selected using `--slasher-backend={lmdb,mdbx}`.
## Additional Info
In order to abstract over the two library's different handling of database lifetimes I've used `Box::leak` to give the `Environment` type a `'static` lifetime. This was the only way I could think of using 100% safe code to construct a self-referential struct `SlasherDB`, where the `OpenDatabases` refers to the `Environment`. I think this is OK, as the `Environment` is expected to live for the life of the program, and both database engines leave the database in a consistent state after each write. The memory claimed for memory-mapping will be freed by the OS and appropriately flushed regardless of whether the `Environment` is actually dropped.
We are depending on two `sigp` forks of `libmdbx-rs` and `lmdb-rs`, to give us greater control over MDBX OS support and LMDB's version.
## Issue Addressed
Closes#2286Closes#2538Closes#2342
## Proposed Changes
Part II of major slasher optimisations after #2767
These changes will be backwards-incompatible due to the move to MDBX (and the schema change) 😱
* [x] Shrink attester keys from 16 bytes to 7 bytes.
* [x] Shrink attester records from 64 bytes to 6 bytes.
* [x] Separate `DiskConfig` from regular `Config`.
* [x] Add configuration for the LRU cache size.
* [x] Add a "migration" that deletes any legacy LMDB database.
## Issue Addressed
Closes https://github.com/sigp/lighthouse/issues/2112
Closes https://github.com/sigp/lighthouse/issues/1861
## Proposed Changes
Collect attestations by validator index in the slasher, and use the magic of reference counting to automatically discard redundant attestations. This results in us storing only 1-2% of the attestations observed when subscribed to all subnets, which carries over to a 50-100x reduction in data stored 🎉
## Additional Info
There's some nuance to the configuration of the `slot-offset`. It has a profound effect on the effictiveness of de-duplication, see the docs added to the book for an explanation: 5442e695e5/book/src/slasher.md (slot-offset)
## Issue Addressed
NA
## Proposed Changes
Updates out of date dependencies.
## Additional Info
See also https://github.com/sigp/lighthouse/issues/1712 for a list of dependencies that are still out of date and the resasons.
This is an implementation of a slasher that lives inside the BN and can be enabled via `lighthouse bn --slasher`.
Features included in this PR:
- [x] Detection of attester slashing conditions (double votes, surrounds existing, surrounded by existing)
- [x] Integration into Lighthouse's attestation verification flow
- [x] Detection of proposer slashing conditions
- [x] Extraction of attestations from blocks as they are verified
- [x] Compression of chunks
- [x] Configurable history length
- [x] Pruning of old attestations and blocks
- [x] More tests
Future work:
* Focus on a slice of history separate from the most recent N epochs (e.g. epochs `current - K` to `current - M`)
* Run out-of-process
* Ingest attestations from the chain without a resync
Design notes are here https://hackmd.io/@sproul/HJSEklmPL
