```\nfunction linkNodeAddress(address validatorAddress, address nodeAddress) external allow("DelegationService") {\n    uint validatorId = getValidatorId(validatorAddress);\n    require(\_validatorAddressToId[nodeAddress] == 0, "Validator cannot override node address");\n    \_validatorAddressToId[nodeAddress] = validatorId;\n}\n\nfunction unlinkNodeAddress(address validatorAddress, address nodeAddress) external allow("DelegationService") {\n    uint validatorId = getValidatorId(validatorAddress);\n    require(\_validatorAddressToId[nodeAddress] == validatorId, "Validator hasn't permissions to unlink node");\n    \_validatorAddressToId[nodeAddress] = 0;\n}\n```\n