PeerDAS fork-choice, validator custody and parameter changes

configs/mainnet.yaml

@@ -157,11 +157,13 @@ WHISK_PROPOSER_SELECTION_GAP: 2
 # EIP7594
 NUMBER_OF_COLUMNS: 128
 MAX_CELLS_IN_EXTENDED_MATRIX: 768
-DATA_COLUMN_SIDECAR_SUBNET_COUNT: 32
+DATA_COLUMN_SIDECAR_SUBNET_COUNT: 128
 MAX_REQUEST_DATA_COLUMN_SIDECARS: 16384
-SAMPLES_PER_SLOT: 8
-CUSTODY_REQUIREMENT: 1
-TARGET_NUMBER_OF_PEERS: 70
+SAMPLES_PER_SLOT: 16
+CUSTODY_REQUIREMENT: 4
+VALIDATOR_CUSTODY_REQUIREMENT: 6
+BALANCE_PER_ADDITIONAL_CUSTODY_SUBNET: 16000000000 # 2**4 * 10**9 (= 16,000,000,000)
+TARGET_NUMBER_OF_PEERS: 100
 
 # [New in Electra:EIP7251]
 MIN_PER_EPOCH_CHURN_LIMIT_ELECTRA: 128000000000 # 2**7 * 10**9 (= 128,000,000,000)

configs/minimal.yaml

@@ -156,11 +156,13 @@ WHISK_PROPOSER_SELECTION_GAP: 1
 # EIP7594
 NUMBER_OF_COLUMNS: 128
 MAX_CELLS_IN_EXTENDED_MATRIX: 768
-DATA_COLUMN_SIDECAR_SUBNET_COUNT: 32
+DATA_COLUMN_SIDECAR_SUBNET_COUNT: 128
 MAX_REQUEST_DATA_COLUMN_SIDECARS: 16384
-SAMPLES_PER_SLOT: 8
-CUSTODY_REQUIREMENT: 1
-TARGET_NUMBER_OF_PEERS: 70
+SAMPLES_PER_SLOT: 16
+CUSTODY_REQUIREMENT: 4
+VALIDATOR_CUSTODY_REQUIREMENT: 6
+BALANCE_PER_ADDITIONAL_CUSTODY_SUBNET: 16000000000 # 2**4 * 10**9 (= 16,000,000,000)
+TARGET_NUMBER_OF_PEERS: 100
 
 # [New in Electra:EIP7251]
 MIN_PER_EPOCH_CHURN_LIMIT_ELECTRA: 64000000000 # 2**6 * 10**9 (= 64,000,000,000)

specs/_features/eip7594/das-core.md

@@ -73,15 +73,18 @@ We define the following Python custom types for type hinting and readability:
 
 | Name | Value | Description |
 | - | - | - |
-| `DATA_COLUMN_SIDECAR_SUBNET_COUNT` | `32` | The number of data column sidecar subnets used in the gossipsub protocol |
+| `DATA_COLUMN_SIDECAR_SUBNET_COUNT` | `128` | The number of data column sidecar subnets used in the gossipsub protocol |
 
 ### Custody setting
 
 | Name | Value | Description |
 | - | - | - |
-| `SAMPLES_PER_SLOT` | `8` | Number of `DataColumn` random samples a node queries per slot |
-| `CUSTODY_REQUIREMENT` | `1` | Minimum number of subnets an honest node custodies and serves samples from |
-| `TARGET_NUMBER_OF_PEERS` | `70` | Suggested minimum peer count |
+| `SAMPLES_PER_SLOT` | `16` | Number of `DataColumn` random samples a node queries per slot |
+| `CUSTODY_REQUIREMENT` | `4` | Minimum number of subnets an honest node custodies and serves samples from |
+| `VALIDATOR_CUSTODY_REQUIREMENT` | `6` | Minimum number of subnets an honest node with validators attached custodies and serves samples from |
+| `BALANCE_PER_ADDITIONAL_CUSTODY_SUBNET` | `Gwei(16 * 10**9)` | Balance increment corresponding to one additional subnet to custody |
+| `TARGET_NUMBER_OF_PEERS` | `100` | Suggested minimum peer count |
+
 
 ### Containers
 
@@ -201,7 +204,15 @@ def get_data_column_sidecars(signed_block: SignedBeaconBlock,
 
 ### Custody requirement
 
-Each node downloads and custodies a minimum of `CUSTODY_REQUIREMENT` subnets per slot. The particular subnets that the node is required to custody are selected pseudo-randomly (more on this below).
+Each node *without attached validators* downloads and custodies a minimum of `CUSTODY_REQUIREMENT` subnets per slot. A node with validators attached downloads and custodies a higher minimum of subnets per slot, determined by `get_validators_custody_requirement(state, validator_indices)`. Here, `state` is the current `BeaconState` and `validator_indices` is the list of indices corresponding to validators attached to the node. Any node with at least one validator attached downloads and custodies a minimum of `VALIDATOR_CUSTODY_REQUIREMENT` subnets per slot, as well as `total_node_balance // BALANCE_PER_ADDITIONAL_CUSTODY_SUBNET` additional subnets, where `total_node_balance` is the sum of the balances of all validators attached to that node.
+
+```python
+def get_validators_custody_requirement(state: BeaconState, validator_indices: List[ValidatorIndex]) -> uint64:
+    total_node_balance = sum(state.balances[index] for index in validator_indices)
+    return VALIDATOR_CUSTODY_REQUIREMENT + (total_node_balance // BALANCE_PER_ADDITIONAL_CUSTODY_SUBNET)
+```
+
+The particular subnets that the node is required to custody are selected pseudo-randomly (more on this below).
 
 A node *may* choose to custody and serve more than the minimum honesty requirement. Such a node explicitly advertises a number greater than `CUSTODY_REQUIREMENT` via the peer discovery mechanism -- for example, in their ENR (e.g. `custody_subnet_count: 4` if the node custodies `4` subnets each slot) -- up to a `DATA_COLUMN_SIDECAR_SUBNET_COUNT` (i.e. a super-full node).
 

specs/_features/eip7594/fork-choice.md

@@ -0,0 +1,173 @@
+# EIP-7594 -- Fork Choice
+
+## Table of contents
+<!-- TOC -->
+<!-- START doctoc generated TOC please keep comment here to allow auto update -->
+<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
+
+- [Introduction](#introduction)
+- [Containers](#containers)
+- [Helpers](#helpers)
+  - [Extended `PayloadAttributes`](#extended-payloadattributes)
+  - [`is_data_available`](#is_data_available)
+- [Updated fork-choice handlers](#updated-fork-choice-handlers)
+  - [`on_block`](#on_block)
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+<!-- /TOC -->
+
+## Introduction
+
+This is the modification of the fork choice accompanying EIP-7594
+
+### Helpers
+
+### `is_data_available`
+
+```python
+def is_data_available(beacon_block_root: Root, require_peer_sampling: bool=False) -> bool:
+    # Unimplemented function which returns the node_id and custody_subnet_count
+    node_id, custody_subnet_count = get_custody_parameters()
+    columns_to_retrieve = get_custody_columns(node_id, custody_subnet_count)
+    if require_peer_sampling:
+        columns_to_retrieve += get_sampling_columns()	
+    column_sidecars = retrieve_column_sidecars(beacon_block_root, columns_to_retrieve)
+    return all(
+        verify_data_column_sidecar_kzg_proofs(column_sidecar)
+        for column_sidecar in column_sidecars
+    )
+```
+
+### `is_chain_available`
+
+```python
+def is_chain_available(store: Store, beacon_block_root: Root) -> bool: 
+    block = store.blocks[beacon_block_root]
+    block_epoch = compute_epoch_at_slot(block.slot)
+    current_epoch = get_current_store_epoch(store)
+    if block_epoch + MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS <= current_epoch:
+        return True
+    parent_root = block.parent_root
+    return (
+        is_data_available(beacon_block_root, require_peer_sampling=True) 
+        and is_chain_available(store, parent_root)
+    )
+
+```
+
+### `get_head`
+
+```python
+def get_head(store: Store) -> Root:
+    # Get filtered block tree that only includes viable branches
+    blocks = get_filtered_block_tree(store)
+    # Execute the LMD-GHOST fork choice
+    head = store.justified_checkpoint.root
+    while True:
+        # Get available children for the current slot
+        children = [
+            root for (root, block) in blocks.items()
+            if (
+                block.parent_root == head
+                and is_data_available(
+                    root, 
+                    require_peer_sampling=is_peer_sampling_required(store, block.slot)
+                )
+            )
+        ]
+        if len(children) == 0:
+            return head
+        # Sort by latest attesting balance with ties broken lexicographically
+        # Ties broken by favoring block with lexicographically higher root
+        head = max(children, key=lambda root: (get_weight(store, root), root))
+```
+
+```python
+def is_peer_sampling_required(store, slot):
+    return compute_epoch_at_slot(slot) + 2 <= get_current_epoch(store)
+```
+
+## Updated fork-choice handlers
+
+### `on_block`
+
+*Note*: The blob data availability check is removed and replaced with an availability
+check on the on the justified checkpoint in the "pulled up state" of the block, after
+applying `process_justification_and_finalization`.
+
+```python
+def on_block(store: Store, signed_block: SignedBeaconBlock) -> None:
+    """
+    Run ``on_block`` upon receiving a new block.
+    """
+    block = signed_block.message
+    # Parent block must be known
+    assert block.parent_root in store.block_states
+    # Make a copy of the state to avoid mutability issues
+    state = copy(store.block_states[block.parent_root])
+    # Blocks cannot be in the future. If they are, their consideration must be delayed until they are in the past.
+    assert get_current_slot(store) >= block.slot
+
+    # Check that block is later than the finalized epoch slot (optimization to reduce calls to get_ancestor)
+    finalized_slot = compute_start_slot_at_epoch(store.finalized_checkpoint.epoch)
+    assert block.slot > finalized_slot
+    # Check block is a descendant of the finalized block at the checkpoint finalized slot
+    finalized_checkpoint_block = get_checkpoint_block(
+        store,
+        block.parent_root,
+        store.finalized_checkpoint.epoch,
+    )
+    assert store.finalized_checkpoint.root == finalized_checkpoint_block
+
+    # Check the block is valid and compute the post-state
+    block_root = hash_tree_root(block)
+    state_transition(state, signed_block, True)
+
+    # [New in EIP7594] Do not import the block if its unrealized justified checkpoint is not available
+    pulled_up_state = state.copy()
+    process_justification_and_finalization(pulled_up_state)
+    assert is_chain_available(store, pulled_up_state.current_justified_checkpoint.root)
+
+    # Add new block to the store
+    store.blocks[block_root] = block
+    # Add new state for this block to the store
+    store.block_states[block_root] = state
+
+    # Add block timeliness to the store
+    time_into_slot = (store.time - store.genesis_time) % SECONDS_PER_SLOT
+    is_before_attesting_interval = time_into_slot < SECONDS_PER_SLOT // INTERVALS_PER_SLOT
+    is_timely = get_current_slot(store) == block.slot and is_before_attesting_interval
+    store.block_timeliness[hash_tree_root(block)] = is_timely
+
+    # Add proposer score boost if the block is timely and not conflicting with an existing block
+    is_first_block = store.proposer_boost_root == Root()
+    if is_timely and is_first_block:
+        store.proposer_boost_root = hash_tree_root(block)
+
+    # Update checkpoints in store if necessary
+    update_checkpoints(store, state.current_justified_checkpoint, state.finalized_checkpoint)
+
+    # Eagerly compute unrealized justification and finality.
+    compute_pulled_up_tip(store, block_root, pulled_up_state)
+```
+
+#### Pull-up tip helpers
+
+##### `compute_pulled_up_tip`
+
+Modified to take `pulled_up_state`, the block's state after applying `processing_justification_and_finalization`.
+The application of `processing_justification_and_finalization` now happens in `on_block`.
+
+```python
+def compute_pulled_up_tip(store: Store, pulled_up_state: BeaconState, block_root: Root) -> None:
+    store.unrealized_justifications[block_root] = pulled_up_state.current_justified_checkpoint
+    unrealized_justified = pulled_up_state.current_justified_checkpoint
+    unrealized_finalized = pulled_up_state.finalized_checkpoint
+    update_unrealized_checkpoints(store, unrealized_justified, unrealized_finalized)
+
+    # If the block is from a prior epoch, apply the realized values
+    block_epoch = compute_epoch_at_slot(store.blocks[block_root].slot)
+    current_epoch = get_current_store_epoch(store)
+    if block_epoch < current_epoch:
+        update_checkpoints(store, unrealized_justified, unrealized_finalized)
+```