Add IsWorkerAddress method

FIPS/fip-0066.md

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+---
+fip: "0066"
+title: Extension of Runtime Methods for Address Verification
+author: "David Casem <@dcasem>"
+discussions-to: https://github.com/filecoin-project/FIPs/discussions/401
+status: Draft
+type: Technical
+category: Core
+created: 2023-07-24
+---
+
+## Simple Summary
+Introduces a method to the built-in Miner actor for address validation to be used in determining \
+whether a given address corresponds to the worker of the queried Miner on the Filecoin network.
+
+## Abstract
+The proposed FIP introduces a new method to the built-in miner actor for address validation to be used in determining \
+whether a given address corresponds to the worker of the queried Miner on the Filecoin network.
+
+## Change Motivation
+There are several scenarios in the Filecoin protocol where it is necessary to confirm if a particular address belongs to a miner actor as a worker key. Having a dedicated exported method in the miner actorto handle such checks can increase efficiency and readability of the codebase.
+
+## Specification
+We propose to introduce a new method: `is_worker_address()` to the Miner actor. This function receives an address as parameter and returns a boolean indicating whether this address corresponds to a worker in the network or not. The function implements a logic to resolve the address and checks it against the current worker address.
+
+Pseudocode
+
+The pseudocode below demonstrates the intended implementation of the `is_worker_address()` function:
+```function is_worker_address(rt: Runtime, params: IsWorkerAddressParams) returns Result<IsWorkerAddressReturn, ActorError>:
+
+    // Accept any caller
+    rt.validate_immediate_caller_accept_any()
+
+    // Resolve the address
+    address = rt.resolve_address(params.address)
+
+    // If address is null, return false
+    if address is null:
+        return Ok(IsWorkerAddressReturn { is_worker: false })
+
+    // Fetch the current state
+    state = rt.state()
+
+    // Retrieve the miner info
+    info = get_miner_info(rt.store(), state)
+
+    // Check if the resolved address matches the worker address
+    is_worker = (address == info.worker)
+
+    // Return the result
+    return Ok(IsWorkerReturn { is_worker })
+```
+
+## Backwards Compatibility
+This proposal should not have any backward compatibility issues. The function is a new addition and does not alter any existing methods or structures.
+
+## Test Cases
+To ensure the correctness of the `is_worker_address()` function, multiple test cases covering different scenarios (worker/non-worker addresses, non-resolvable addresses etc.) should be considered
+
+
+Possible Tests:
+
+`IsWorkerAddress` correctly identifies the worker address
+
+`IsWorkerAddress` correctly identifies non-worker addresses
+
+## Implementation
+This FIP does not require any changes to existing protocols. The changes would be implemented in the actor package in the. The exact implementation details will depend on the codebase at the time of implementation.
+
+
+## Security Considerations
+The proposed function does not introduce any new security considerations as it only checks existing data structures. It is important to ensure that the function is implemented correctly to avoid any potential security issues.
+
+## Implementation
+This FIP does not require any changes to existing protocols. The changes would be implemented in the `actor` package. The exact implementation details will depend on the codebase at the time of implementation.
+
+## Copyright
+Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).