Use all attestation subnets (#1257)

* Update `milagro_bls` to new release (#1183)

* Update milagro_bls to new release

Signed-off-by: Kirk Baird <baird.k@outlook.com>

* Tidy up fake cryptos

Signed-off-by: Kirk Baird <baird.k@outlook.com>

* move SecretHash to bls and put plaintext back

Signed-off-by: Kirk Baird <baird.k@outlook.com>

* Update v0.12.0 to v0.12.1

* Add compute_subnet_for_attestation

* Replace CommitteeIndex topic with Attestation

* Fix warnings

* Fix attestation service tests

* fmt

* Appease clippy

* return error from validator_subscriptions

* move state out of loop

* Fix early break on error

* Get state from slot clock

* Fix beacon state in attestation tests

* Add failing test for lookahead > 1

* Minor change

* Address some review comments

* Add subnet verification to beacon chain

* Move subnet verification to processor

* Pass committee_count_at_slot to ValidatorDuty and ValidatorSubscription

* Pass subnet id for publishing attestations

* Fix attestation service tests

* Fix more tests

* Fix fork choice test

* Remove unused code

* Remove more unused and expensive code

Co-authored-by: Kirk Baird <baird.k@outlook.com>
Co-authored-by: Michael Sproul <michael@sigmaprime.io>
Co-authored-by: Age Manning <Age@AgeManning.com>
Co-authored-by: Paul Hauner <paul@paulhauner.com>

consensus/types/src/attestation.rs

@@ -1,10 +1,9 @@
 use super::{
     AggregateSignature, AttestationData, BitList, ChainSpec, Domain, EthSpec, Fork, SecretKey,
-    Signature, SignedRoot, SubnetId,
+    Signature, SignedRoot,
 };
 use crate::{test_utils::TestRandom, Hash256};
-use safe_arith::{ArithError, SafeArith};
-
+use safe_arith::ArithError;
 use serde_derive::{Deserialize, Serialize};
 use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
@@ -84,18 +83,6 @@ impl<T: EthSpec> Attestation<T> {
             Ok(())
         }
     }
-
-    /// Returns the subnet id associated with the attestation.
-    ///
-    /// Note, this will return the subnet id for an aggregated attestation. This is done
-    /// to avoid checking aggregate bits every time we wish to get an id.
-    pub fn subnet_id(&self, spec: &ChainSpec) -> Result<SubnetId, Error> {
-        self.data
-            .index
-            .safe_rem(spec.attestation_subnet_count)
-            .map(SubnetId::new)
-            .map_err(Error::SubnetCountIsZero)
-    }
 }
 
 #[cfg(test)]

consensus/types/src/beacon_block.rs

@@ -83,12 +83,12 @@ impl<T: EthSpec> BeaconBlock<T> {
         };
         let proposer_slashing = ProposerSlashing {
             signed_header_1: signed_header.clone(),
-            signed_header_2: signed_header.clone(),
+            signed_header_2: signed_header,
         };
 
         let attester_slashing = AttesterSlashing {
             attestation_1: indexed_attestation.clone(),
-            attestation_2: indexed_attestation.clone(),
+            attestation_2: indexed_attestation,
         };
 
         let attestation: Attestation<T> = Attestation {

consensus/types/src/subnet_id.rs

@@ -1,4 +1,6 @@
 //! Identifies each shard by an integer identifier.
+use crate::{AttestationData, ChainSpec, CommitteeIndex, EthSpec, Slot};
+use safe_arith::{ArithError, SafeArith};
 use serde_derive::{Deserialize, Serialize};
 use std::ops::{Deref, DerefMut};
 
@@ -8,7 +10,42 @@ pub struct SubnetId(u64);
 
 impl SubnetId {
     pub fn new(id: u64) -> Self {
-        SubnetId(id)
+        id.into()
+    }
+
+    /// Compute the subnet for an attestation with `attestation_data` where each slot in the
+    /// attestation epoch contains `committee_count_per_slot` committees.
+    pub fn compute_subnet_for_attestation_data<T: EthSpec>(
+        attestation_data: &AttestationData,
+        committee_count_per_slot: u64,
+        spec: &ChainSpec,
+    ) -> Result<SubnetId, ArithError> {
+        Self::compute_subnet::<T>(
+            attestation_data.slot,
+            attestation_data.index,
+            committee_count_per_slot,
+            spec,
+        )
+    }
+
+    /// Compute the subnet for an attestation with `attestation.data.slot == slot` and
+    /// `attestation.data.index == committee_index` where each slot in the attestation epoch
+    /// contains `committee_count_at_slot` committees.
+    pub fn compute_subnet<T: EthSpec>(
+        slot: Slot,
+        committee_index: CommitteeIndex,
+        committee_count_at_slot: u64,
+        spec: &ChainSpec,
+    ) -> Result<SubnetId, ArithError> {
+        let slots_since_epoch_start: u64 = slot.as_u64().safe_rem(T::slots_per_epoch())?;
+
+        let committees_since_epoch_start =
+            committee_count_at_slot.safe_mul(slots_since_epoch_start)?;
+
+        Ok(committees_since_epoch_start
+            .safe_add(committee_index)?
+            .safe_rem(spec.attestation_subnet_count)?
+            .into())
     }
 }
 
@@ -25,3 +62,15 @@ impl DerefMut for SubnetId {
         &mut self.0
     }
 }
+
+impl From<u64> for SubnetId {
+    fn from(x: u64) -> Self {
+        Self(x)
+    }
+}
+
+impl Into<u64> for SubnetId {
+    fn into(self) -> u64 {
+        self.0
+    }
+}