Add register_validator endpoint

apis/validator/register_validator.yaml

@@ -0,0 +1,30 @@
+post:
+  operationId: "registerValidator"
+  summary: Provide beacon node with registrations for the given validators to the external builder network.
+  description: |
+    Prepares the beacon node for engaging with external builders. The
+    information will be sent by the beacon node to the builder network. It is
+    expected that the validator client will send this information periodically
+    to ensure the beacon node has correct and timely registration information
+    to provide to builders. The validator client should not sign blinded beacon
+    blocks that do not adhere to their latest fee recipient and gas limit
+    preferences.
+
+    Note that requests containing currently inactive or unknown validator
+    pubkeys will be accepted, as they may become active at a later epoch.
+  tags:
+    - Validator
+  requestBody:
+    content:
+      application/json:
+        schema:
+          type: array
+          items:
+              $ref: '../../beacon-node-oapi.yaml#/components/schemas/SignedValidatorRegistration'
+  responses:
+    "200":
+      description: Registration information has been received.
+    "400":
+      $ref: '../../beacon-node-oapi.yaml#/components/responses/InvalidRequest'
+    "500":
+      $ref: '../../beacon-node-oapi.yaml#/components/responses/InternalError'

beacon-node-oapi.yaml

@@ -161,6 +161,8 @@ paths:
     $ref: "./apis/validator/sync_committee_contribution_and_proof.yaml"
   /eth/v1/validator/prepare_beacon_proposer:
     $ref: "./apis/validator/prepare_beacon_proposer.yaml"
+  /eth/v1/validator/register_validator:
+    $ref: "./apis/validator/register_validator.yaml"
 
   /eth/v1/events:
     $ref: "./apis/eventstream/index.yaml"
@@ -273,6 +275,9 @@ components:
     ConsensusVersion:
       enum: [phase0, altair, bellatrix]
       example: "phase0"
+    SignedValidatorRegistration:
+      $ref: './types/registration.yaml#/SignedValidatorRegistration'
+
   parameters:
     StateId:
       $ref: './params/index.yaml#/StateId'

types/registration.yaml

@@ -0,0 +1,25 @@
+ValidatorRegistration:
+  type: object
+  description: "The `ValidatorRegistration` object from the Builder API specification."
+  properties:
+    fee_recipient:
+      $ref: 'primitive.yaml#/ExecutionAddress'
+      description: "Address to receive fees from the block."
+    gas_limit:
+      $ref: "primitive.yaml#/Uint64"
+      description: "Preferred gas limit of validator."
+    timestamp:
+      $ref: 'primitive.yaml#/Uint64'
+      description: "Unix timestamp of registration."
+    pubkey:
+      $ref: 'primitive.yaml#/Pubkey'
+      description: "BLS public key of validator."
+
+SignedValidatorRegistration:
+  type: object
+  description: "The `SignedValidatorRegistration` object from the Builder API specification."
+  properties:
+    message:
+      $ref: "#/ValidatorRegistration"
+    signature:
+      $ref: "primitive.yaml#/Signature"