From cd7dbef16f246b0bc2edff14f9d8284210de343d Mon Sep 17 00:00:00 2001 From: Potuz Date: Tue, 25 Jun 2024 13:58:41 +0200 Subject: [PATCH] P2P changes --- specs/_features/epbs/p2p-interface.md | 258 ++++++++++++++++++++++++++ 1 file changed, 258 insertions(+) create mode 100644 specs/_features/epbs/p2p-interface.md diff --git a/specs/_features/epbs/p2p-interface.md b/specs/_features/epbs/p2p-interface.md new file mode 100644 index 000000000..9d89b0dc5 --- /dev/null +++ b/specs/_features/epbs/p2p-interface.md @@ -0,0 +1,258 @@ +# ePBS -- Networking + +This document contains the consensus-layer networking specification for ePBS. + + + + +- [Modification in EIP-XXXX](#modification-in-eip-xxxx) + - [Preset](#preset) + - [Containers](#containers) + - [`BlobSidecar`](#blobsidecar) + - [Helpers](#helpers) + - [Modified `verify_blob_sidecar_inclusion_proof`](#modified-verify_blob_sidecar_inclusion_proof) + - [The gossip domain: gossipsub](#the-gossip-domain-gossipsub) + - [Topics and messages](#topics-and-messages) + - [Global topics](#global-topics) + - [`beacon_block`](#beacon_block) + - [`execution_payload`](#execution_payload) + - [`payload_attestation_message`](#payload_attestation_message) + - [`execution_payload_header`](#execution_payload_header) + - [The Req/Resp domain](#the-reqresp-domain) + - [Messages](#messages) + - [BeaconBlocksByRange v3](#beaconblocksbyrange-v3) + - [BeaconBlocksByRoot v3](#beaconblocksbyroot-v3) + - [BlobSidecarsByRoot v2](#blobsidecarsbyroot-v2) + - [ExecutionPayloadEnvelopeByRoot v1](#executionpayloadenvelopebyroot-v1) + + + +## Modification in EIP-XXXX + +### Preset + +*[Modified in EIP-XXXX]* + +| Name | Value | Description | +|------------------------------------------|-----------------------------------|---------------------------------------------------------------------| +| `KZG_COMMITMENT_INCLUSION_PROOF_DEPTH` | TODO: Compute it when the spec stabilizes | Merkle proof depth for the `blob_kzg_commitments` list item | +| `KZG_GENERALIZED_INDEX_PREFIX` | TODO: Compute it when the spec stabilizes | Generalized index for the first item in the `blob_kzg_commitments` list | + +### Containers + +#### `BlobSidecar` + +The `BlobSidecar` container is modified indirectly because the constant `KZG_COMMITMENT_INCLUSION_PROOF_DEPTH` is modified. + +```python +class BlobSidecar(Container): + index: BlobIndex # Index of blob in block + blob: Blob + kzg_commitment: KZGCommitment + kzg_proof: KZGProof # Allows for quick verification of kzg_commitment + signed_block_header: SignedBeaconBlockHeader + kzg_commitment_inclusion_proof: Vector[Bytes32, KZG_COMMITMENT_INCLUSION_PROOF_DEPTH] +``` + +#### Helpers + +##### Modified `verify_blob_sidecar_inclusion_proof` + +`verify_blob_sidecar_inclusion_proof` is modified in EIP-XXXX to account for the fact that the KZG commitments are included in the `ExecutionPayloadEnvelope` and no longer in the beacon block body. + +```python +def verify_blob_sidecar_inclusion_proof(blob_sidecar: BlobSidecar) -> bool: + # hardcoded here because the block does not include the commitments but only their root. + gindex = GeneralizedIndex(KZG_GENERALIZED_INDEX_PREFIX + blob_sidecar.index) + + return is_valid_merkle_branch( + leaf=blob_sidecar.kzg_commitment.hash_tree_root(), + branch=blob_sidecar.kzg_commitment_inclusion_proof, + depth=KZG_COMMITMENT_INCLUSION_PROOF_DEPTH, + index=gindex, + root=blob_sidecar.signed_block_header.message.body_root, + ) +``` + +### The gossip domain: gossipsub + +Some gossip meshes are upgraded in the fork of EIP-XXXX to support upgraded types. + +#### Topics and messages + +Topics follow the same specification as in prior upgrades. + +The `beacon_block` topic is updated to support the modified type +| Name | Message Type | +| --- | --- | +| `beacon_block` | `SignedBeaconBlock` [modified in EIP-XXXX] | + +The new topics along with the type of the `data` field of a gossipsub message are given in this table: + +| Name | Message Type | +|-------------------------------|------------------------------------------------------| +| `execution_payload_header` | `SignedExecutionPayloadHeader` [New in EIP-XXXX] | +| `execution_payload` | `SignedExecutionPayloadEnvelope` [New in EIP-XXXX] | +| `payload_attestation_message` | `PayloadAttestationMessage` [New in EIP-XXXX] | + +##### Global topics + +EIP-XXXX introduces new global topics for execution header, execution payload and payload attestation. + +###### `beacon_block` + +[Modified in EIP-XXXX] + +The *type* of the payload of this topic changes to the (modified) `SignedBeaconBlock` found in [the Beacon Chain changes](./beacon-chain.md). + +There are no new validations for this topic. However, all validations with regards to the `ExecutionPayload` are removed: + +- _[REJECT]_ The length of KZG commitments is less than or equal to the limitation defined in Consensus Layer -- i.e. validate that len(body.signed_beacon_block.message.blob_kzg_commitments) <= MAX_BLOBS_PER_BLOCK +- _[REJECT]_ The block's execution payload timestamp is correct with respect to the slot + -- i.e. `execution_payload.timestamp == compute_timestamp_at_slot(state, block.slot)`. +- If `execution_payload` verification of block's parent by an execution node is *not* complete: + - [REJECT] The block's parent (defined by `block.parent_root`) passes all validation (excluding execution node verification of the `block.body.execution_payload`). +- otherwise: + - [IGNORE] The block's parent (defined by `block.parent_root`) passes all validation (including execution node verification of the `block.body.execution_payload`). +- [REJECT] The block's parent (defined by `block.parent_root`) passes validation. + +And instead the following validations are set in place with the alias `header = signed_execution_payload_header.message`: + +- If `execution_payload` verification of block's execution payload parent by an execution node **is complete**: + - [REJECT] The block's execution payload parent (defined by `header.parent_block_hash`) passes all validation. +- [REJECT] The block's parent (defined by `block.parent_root`) passes validation. + +###### `execution_payload` + +This topic is used to propagate execution payload messages as `SignedExecutionPayloadEnvelope`. + +The following validations MUST pass before forwarding the `signed_execution_payload_envelope` on the network, assuming the alias `envelope = signed_execution_payload_envelope.message`, `payload = payload_envelope.payload`: + +- _[IGNORE]_ The envelope's block root `envelope.block_root` has been seen (via both gossip and non-gossip sources) (a client MAY queue payload for processing once the block is retrieved). +- _[IGNORE]_ The node has not seen another valid `SignedExecutionPayloadEnvelope` for this block root from this builder. + +Let `block` be the block with `envelope.beacon_block_root`. +Let `header` alias `block.body.signed_execution_payload_header.message` (notice that this can be obtained from the `state.signed_execution_payload_header`) +- _[REJECT]_ `block` passes validation. +- _[REJECT]_ `envelope.builder_index == header.builder_index` +- if `envelope.payload_withheld == False` then + - _[REJECT]_ `payload.block_hash == header.block_hash` +- _[REJECT]_ The builder signature, `signed_execution_payload_envelope.signature`, is valid with respect to the builder's public key. + +###### `payload_attestation_message` + +This topic is used to propagate signed payload attestation message. + +The following validations MUST pass before forwarding the `payload_attestation_message` on the network, assuming the alias `data = payload_attestation_message.data`: + +- _[IGNORE]_ `data.slot` is the current slot. +- _[REJECT]_ `data.payload_status < PAYLOAD_INVALID_STATUS` +- _[IGNORE]_ the `payload_attestation_message` is the first valid payload attestation message received from the validator index. +- _[IGNORE]_ The attestation's `data.beacon_block_root` has been seen (via both gossip and non-gossip sources) (a client MAY queue attestation for processing once the block is retrieved. Note a client might want to request payload after). +_ _[REJECT]_ The beacon block with root `data.beacon_block_root` passes validation. +- _[REJECT]_ The validator index is within the payload committee in `get_ptc(state, data.slot)`. For the current's slot head state. +- _[REJECT]_ The signature of `payload_attestation_message.signature` is valid with respect to the validator index. + +###### `execution_payload_header` + +This topic is used to propagate signed bids as `SignedExecutionPayloadHeader`. + +The following validations MUST pass before forwarding the `signed_execution_payload_header` on the network, assuming the alias `header = signed_execution_payload_header.message`: + +- _[IGNORE]_ this is the first signed bid seen with a valid signature from the given builder for this slot. +- _[IGNORE]_ this bid is the highest value bid seen for the pair of the corresponding slot and the given parent block hash. +- _[REJECT]_ The signed builder bid, `header.builder_index` is a valid and non-slashed builder index in state. +- _[IGNORE]_ The signed builder bid value, `header.value`, is less or equal than the builder's balance in state. i.e. `MIN_BUILDER_BALANCE + header.value < state.builder_balances[header.builder_index]`. +- _[IGNORE]_ `header.parent_block_hash` is the block hash of a known execution payload in fork choice. +- _[IGNORE]_ `header.slot` is the current slot or the next slot. +- _[REJECT]_ The builder signature, `signed_execution_payload_header_envelope.signature`, is valid with respect to the `header_envelope.builder_index`. + +### The Req/Resp domain + +#### Messages + +##### BeaconBlocksByRange v3 + +**Protocol ID:** `/eth2/beacon_chain/req/beacon_blocks_by_range/3/` + +[0]: # (eth2spec: skip) + +| `fork_version` | Chunk SSZ type | +|--------------------------|-------------------------------| +| `GENESIS_FORK_VERSION` | `phase0.SignedBeaconBlock` | +| `ALTAIR_FORK_VERSION` | `altair.SignedBeaconBlock` | +| `BELLATRIX_FORK_VERSION` | `bellatrix.SignedBeaconBlock` | +| `CAPELLA_FORK_VERSION` | `capella.SignedBeaconBlock` | +| `DENEB_FORK_VERSION` | `deneb.SignedBeaconBlock` | +| `EPBS_FORK_VERSION` | `epbs.SignedBeaconBlock` | + +##### BeaconBlocksByRoot v3 + +**Protocol ID:** `/eth2/beacon_chain/req/beacon_blocks_by_root/3/` + +Per `context = compute_fork_digest(fork_version, genesis_validators_root)`: + +[1]: # (eth2spec: skip) + +| `fork_version` | Chunk SSZ type | +|--------------------------|-------------------------------| +| `GENESIS_FORK_VERSION` | `phase0.SignedBeaconBlock` | +| `ALTAIR_FORK_VERSION` | `altair.SignedBeaconBlock` | +| `BELLATRIX_FORK_VERSION` | `bellatrix.SignedBeaconBlock` | +| `CAPELLA_FORK_VERSION` | `capella.SignedBeaconBlock` | +| `DENEB_FORK_VERSION` | `deneb.SignedBeaconBlock` | +| `EPBS_FORK_VERSION` | `epbs.SignedBeaconBlock` | + + +##### BlobSidecarsByRoot v2 + +**Protocol ID:** `/eth2/beacon_chain/req/blob_sidecars_by_root/2/` + +[1]: # (eth2spec: skip) + +| `fork_version` | Chunk SSZ type | +|--------------------------|-------------------------------| +| `DENEB_FORK_VERSION` | `deneb.BlobSidecar` | +| `EPBS_FORK_VERSION` | `epbs.BlobSidecar` | + + +##### ExecutionPayloadEnvelopeByRoot v1 + +**Protocol ID:** `/eth2/beacon_chain/req/execution_payload_envelope_by_root/1/` + +The `` field is calculated as `context = compute_fork_digest(fork_version, genesis_validators_root)`: + +[1]: # (eth2spec: skip) + +| `fork_version` | Chunk SSZ type | +|---------------------|---------------------------------------| +| `EPBS_FORK_VERSION` | `epbs.SignedExecutionPayloadEnvelope` | + +Request Content: + +``` +( + List[Root, MAX_REQUEST_PAYLOAD] +) +``` + +Response Content: + +``` +( + List[SignedExecutionPayloadEnvelope, MAX_REQUEST_PAYLOAD] +) +``` +Requests execution payload envelope by `signed_execution_payload_envelope.message.block_root`. The response is a list of `SignedExecutionPayloadEnvelope` whose length is less than or equal to the number of requested execution payload envelopes. It may be less in the case that the responding peer is missing payload envelopes. + +No more than `MAX_REQUEST_PAYLOAD` may be requested at a time. + +ExecutionPayloadEnvelopeByRoot is primarily used to recover recent execution payload envelope (e.g. when receiving a payload attestation with revealed status as true but never received a payload). + +The request MUST be encoded as an SSZ-field. + +The response MUST consist of zero or more `response_chunk`. Each successful `response_chunk` MUST contain a single `SignedExecutionPayloadEnvelope` payload. + +Clients MUST support requesting payload envelopes since the latest finalized epoch. + +Clients MUST respond with at least one payload envelope, if they have it. Clients MAY limit the number of payload envelopes in the response.