132 lines
5.7 KiB
Markdown
132 lines
5.7 KiB
Markdown
# The Merge -- Networking
|
|
|
|
This document contains the networking specification for the Merge.
|
|
|
|
The specification of these changes continues in the same format as the network specifications of previous upgrades, and assumes them as pre-requisite. This document should be viewed as additive to the documents from [Phase 0](../phase0/p2p-interface.md) and from [Altair](../altair/p2p-interface.md)
|
|
and will be referred to as the "Phase 0 document" and "Altair document" respectively, hereafter.
|
|
Readers should understand the Phase 0 and Altair documents and use them as a basis to understand the changes outlined in this document.
|
|
|
|
## 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 -->
|
|
|
|
- [Warning](#warning)
|
|
- [Modifications in the Merge](#modifications-in-the-merge)
|
|
- [The gossip domain: gossipsub](#the-gossip-domain-gossipsub)
|
|
- [Topics and messages](#topics-and-messages)
|
|
- [Global topics](#global-topics)
|
|
- [`beacon_block`](#beacon_block)
|
|
- [Transitioning the gossip](#transitioning-the-gossip)
|
|
- [The Req/Resp domain](#the-reqresp-domain)
|
|
- [Messages](#messages)
|
|
- [BeaconBlocksByRange v2](#beaconblocksbyrange-v2)
|
|
- [BeaconBlocksByRoot v2](#beaconblocksbyroot-v2)
|
|
|
|
<!-- END doctoc generated TOC please keep comment here to allow auto update -->
|
|
<!-- /TOC -->
|
|
|
|
## Warning
|
|
|
|
This document is currently illustrative for early Merge testnets and some parts are subject to change.
|
|
Refer to the note in the [validator guide](./validator.md) for further details.
|
|
|
|
# Modifications in the Merge
|
|
|
|
## The gossip domain: gossipsub
|
|
|
|
Some gossip meshes are upgraded in the Merge to support upgraded types.
|
|
|
|
### Topics and messages
|
|
|
|
Topics follow the same specification as in prior upgrades.
|
|
All topics remain stable except the beacon block topic which is updated with the modified type.
|
|
|
|
The specification around the creation, validation, and dissemination of messages has not changed from the Phase 0 and Altair documents.
|
|
|
|
The derivation of the `message-id` remains stable.
|
|
|
|
The new topics along with the type of the `data` field of a gossipsub message are given in this table:
|
|
|
|
| Name | Message Type |
|
|
| - | - |
|
|
| `beacon_block` | `SignedBeaconBlock` (modified) |
|
|
|
|
Note that the `ForkDigestValue` path segment of the topic separates the old and the new `beacon_block` topics.
|
|
|
|
#### Global topics
|
|
|
|
The Merge changes the type of the global beacon block topic.
|
|
|
|
##### `beacon_block`
|
|
|
|
The *type* of the payload of this topic changes to the (modified) `SignedBeaconBlock` found in the Merge.
|
|
Specifically, this type changes with the addition of `execution_payload` to the inner `BeaconBlockBody`.
|
|
See the Merge [state transition document](./beacon-chain.md#beaconblockbody) for further details.
|
|
|
|
In addition to the gossip validations for this topic from prior specifications,
|
|
the following validations MUST pass before forwarding the `signed_beacon_block` on the network.
|
|
Alias `block = signed_beacon_block.message`, `execution_payload = block.body.execution_payload`.
|
|
- If the merge is complete with respect to the head state -- i.e. `is_merge_complete(state)` --
|
|
then validate the following:
|
|
- _[REJECT]_ The block's execution payload must be non-empty --
|
|
i.e. `execution_payload != ExecutionPayload()`
|
|
- If the execution is enabled for the block -- i.e. `is_execution_enabled(state, block.body)`
|
|
then validate the following:
|
|
- _[REJECT]_ The block's execution payload timestamp is correct with respect to the slot
|
|
-- i.e. `execution_payload.timestamp == compute_time_at_slot(state, block.slot)`.
|
|
- _[REJECT]_ Gas used is less than the gas limit --
|
|
i.e. `execution_payload.gas_used <= execution_payload.gas_limit`.
|
|
- _[REJECT]_ The execution payload block hash is not equal to the parent hash --
|
|
i.e. `execution_payload.block_hash != execution_payload.parent_hash`.
|
|
- _[REJECT]_ The execution payload transaction list data is within expected size limits,
|
|
the data MUST NOT be larger than the SSZ list-limit,
|
|
and a client MAY be more strict.
|
|
|
|
*Note*: Additional [gossip validations](https://github.com/ethereum/devp2p/blob/master/caps/eth.md#block-encoding-and-validity)
|
|
(see block "data validity" conditions) that rely more heavily on execution-layer state and logic are currently under consideration.
|
|
|
|
### Transitioning the gossip
|
|
|
|
See gossip transition details found in the [Altair document](../altair/p2p) for
|
|
details on how to handle transitioning gossip topics for the Merge.
|
|
|
|
## The Req/Resp domain
|
|
|
|
### Messages
|
|
|
|
#### BeaconBlocksByRange v2
|
|
|
|
**Protocol ID:** `/eth2/beacon_chain/req/beacon_blocks_by_range/2/`
|
|
|
|
Request and Response remain unchanged.
|
|
The Merge fork-digest is introduced to the `context` enum to specify the Merge block type.
|
|
|
|
Per `context = compute_fork_digest(fork_version, genesis_validators_root)`:
|
|
|
|
[0]: # (eth2spec: skip)
|
|
|
|
| `fork_version` | Chunk SSZ type |
|
|
| ------------------------ | -------------------------- |
|
|
| `GENESIS_FORK_VERSION` | `phase0.SignedBeaconBlock` |
|
|
| `ALTAIR_FORK_VERSION` | `altair.SignedBeaconBlock` |
|
|
| `MERGE_FORK_VERSION` | `merge.SignedBeaconBlock` |
|
|
|
|
#### BeaconBlocksByRoot v2
|
|
|
|
**Protocol ID:** `/eth2/beacon_chain/req/beacon_blocks_by_root/2/`
|
|
|
|
Request and Response remain unchanged.
|
|
The Merge fork-digest is introduced to the `context` enum to specify the Merge block type.
|
|
|
|
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` |
|
|
| `MERGE_FORK_VERSION` | `merge.SignedBeaconBlock` |
|