Merge pull request #70 from ethereum/vbuterin-patch-1

Rework validator exiting, add min balance clause
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Danny Ryan 2018-10-15 12:28:10 -05:00 committed by GitHub
commit 4c2ecab280
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1 changed files with 18 additions and 9 deletions

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@ -43,6 +43,7 @@ The primary source of load on the beacon chain are "attestations". Attestations
| `BASE_REWARD_QUOTIENT` | 2**15 (= 32,768) | — |
| `MAX_VALIDATOR_CHURN_QUOTIENT` | 2**5 (= 32) | — |
| `LOGOUT_MESSAGE` | `"LOGOUT"` | — |
| `MIN_ONLINE_DEPOSIT_SIZE` | 2**4 (= 16) | ETH |
**Notes**
@ -565,6 +566,20 @@ def add_validator(validators: List[ValidatorRecord],
return index
```
## Routine for removing a validator
```python
def exit_validator(index, crystallized_state, penalize, current_slot):
validator = crystallized_state.validators[index]
validator.exit_slot = current_slot
if penalize:
validator.status = PENALIZED
crystallized_state.deposits_penalized_in_period[current_slot // WITHDRAWAL_PERIOD] += validator.balance
else:
validator.status = PENDING_EXIT
add_validator_set_change_record(crystallized_state, index, validator.pubkey, EXIT)
```
### Per-block processing
This procedure should be carried out every block.
@ -669,19 +684,13 @@ In addition, validators with `status == PENALIZED` lose `B // reward_quotient +
For each `SpecialRecord` `obj` in `active_state.pending_specials`:
* **[covers logouts]**: If `obj.kind == LOGOUT`, interpret `data[0]` as a validator index as an `int32` and `data[1]` as a signature. If `BLSVerify(pubkey=validators[data[0]].pubkey, msg=hash(LOGOUT_MESSAGE + bytes8(version)), sig=data[1])`, where `version = pre_fork_version if slot < fork_slot_number else post_fork_version`, returns True, and `validators[i].status == ACTIVE`, set `validators[i].status = PENDING_EXIT` and `validators[i].exit_slot = current_slot`.
* **[covers `NO_DBL_VOTE`, `NO_SURROUND`, `NO_DBL_PROPOSE` slashing conditions]:** If `obj.kind == CASPER_SLASHING`, interpret `data[0]` as a list of concatenated `int32` values where each value represents an index into `validators`, `data[1]` as the data being signed and `data[2]` as an aggregate signature. Interpret `data[3:6]` similarly. Verify that both signatures are valid, that the two signatures are signing distinct data, and that they are either signing the same slot number, or that one surrounds the other (ie. `source1 < source2 < target2 < target1`). Let `indices` be the list of indices in both signatures; verify that its length is at least 1. For each validator index `v` in `indices`, if its `status` does not equal `PENALIZED`, then:
1. Set its `exit_slot` to equal the current `slot`
2. Set its `status` to `PENALIZED`
3. Set `crystallized_state.deposits_penalized_in_period[slot // WITHDRAWAL_PERIOD] += validators[v].balance`, extending the array if needed
4. Run `add_validator_set_change_record(crystallized_state, v, validators[v].pubkey, EXIT)`
* **[covers logouts]**: If `obj.kind == LOGOUT`, interpret `data[0]` as a validator index as an `int32` and `data[1]` as a signature. If `BLSVerify(pubkey=validators[data[0]].pubkey, msg=hash(LOGOUT_MESSAGE + bytes8(version)), sig=data[1])`, where `version = pre_fork_version if slot < fork_slot_number else post_fork_version`, and `validators[i].status == ACTIVE`, run `exit_validator(data[0], crystallized_state, penalize=False, current_slot=block.slot)`
* **[covers `NO_DBL_VOTE`, `NO_SURROUND`, `NO_DBL_PROPOSE` slashing conditions]:** If `obj.kind == CASPER_SLASHING`, interpret `data[0]` as a list of concatenated `int32` values where each value represents an index into `validators`, `data[1]` as the data being signed and `data[2]` as an aggregate signature. Interpret `data[3:6]` similarly. Verify that both signatures are valid, that the two signatures are signing distinct data, and that they are either signing the same slot number, or that one surrounds the other (ie. `source1 < source2 < target2 < target1`). Let `indices` be the list of indices in both signatures; verify that its length is at least 1. For each validator index `v` in `indices`, if its `status` does not equal `PENALIZED`, then run `exit_validator(v, crystallized_state, penalize=True, current_slot=block.slot)`
* **[covers RANDAO updates]**: If `obj.kind == RANDAO_REVEAL`, interpret `data[0]` as an integer and `data[1]` as a hash32. Set `validators[data[0]].randao_commitment = data[1]`.
#### Finally...
* For any validator with index `v` with balance less than `MIN_ONLINE_DEPOSIT_SIZE` and status `ACTIVE`, run `exit_validator(v, crystallized_state, penalize=False, current_slot=block.slot)`
* Set `crystallized_state.last_state_recalculation_slot += CYCLE_LENGTH`
* Remove all attestation records older than slot `crystallized_state.last_state_recalculation_slot`
* Empty the `active_state.pending_specials` list