--- openapi: 3.0.3 ############################################################################ # API info # ############################################################################ info: title: Call Forwarding Signal description: | # Overview The Call Forwarding Signal (CFS) API provides the API Consumer with information about the status of the Call Forwading Service on a specific phone number. The main scope of the CFS API is "anti Fraud" to avoid fraudsters to use the Call Forwarding Service to carry on a scam. Other use cases are anyway supported by the CFS API that also provides additional endpoints to detect the general Call Forwarding Service settings. # Introduction The Call Forwarding Service is provided by the Network to a phone number. This service redirects the incoming call to that phone number to an alternative destination such as another phone number or a voice mail system. There are two main types of call forwarding settings: unconditional and conditional. The CFS API can be invoked to detect if the unconditional call forwarding service is active. The CSF API can also be invoked to get the general status of the Call Forwarding Service (inactive, conditional, unconditional). If conditional call forwarding is active, the differente type of settings are returned ('conditional_busy', 'conditional_unavailable', 'conditional_no_reply').\ \ **Example use cases:**\ \ [**Bank Frauds**](https://github.com/camaraproject/CallForwardingSignal\ /discussions/3#discussioncomment-8694420)\ \ [**Alert Interception**](https://github.com/camaraproject/CallForwarding\ Signal/discussions/3#discussioncomment-8701847)\ \ [**Call Forwading Verification**](https://github.com/camaraproject/\ CallForwarding\Signal/discussions/3#discussioncomment-8915595) # Quick Start The CFS API is a REST API based on the CreateCallForwardingSignal resource. This resource can be filled during the API invokation, by the API Consumer, with the phone number on which the Call Forwarding Service status must be verified. Anyway the phone number is also detected, by the API Producer, from the access token.\ \ Before starting to use the Call Forwarding API, the developer needs to know about the below specified details:\ \ **phoneNumber** This is the end user phone number. The CFS API verifies if a call forwarding service is active on this phone number. Note: the value of this optional parameter must match the value of the phone number retrieved from the access token.\ \ **CreateCallForwardingSignal** This is the resource the API Consumer uses to define the phone number to be verified about the status of the Network Call Forwarding service.\ \ **UnconditionalCallForwardingSignal** This is the resource the API Consumer gets back, containing the information about the Unconditional Call Forwarding Service status for the given phone number (PhoneNumber)\ \ **CallForwardingSignal** This is the resource the API Consumer gets back, containing the information about the general status of the Network Call Forwarding service for the specified phone number.\ \ The CFS API provides two endpoints fulfilling the following intents: - **unconditional-call-forwardings**: Is the unconditional call fwd service active on a specific phone number? - **call-forwardings**: Which is the status of the call forwarding for a specific phone number? # Authorization and authentication The "Camara Security and Interoperability Profile" provides details on how a client requests an access token. Please refer to Identify and Consent Management (https://github.com/camaraproject/IdentityAndConsentManagement/) for the released version of the Profile.\ \ Which specific authorization flows are to be used will be determined during onboarding process, happening between the API Client and the Telco Operator exposing the API, taking into account the declared purpose for accessing the API, while also being subject to the prevailing legal framework dictated by local legislation.\ \ It is important to remark that in cases where personal user data is processed by the API, and users can exercise their rights through mechanisms such as opt-in and/or opt-out, the use of 3-legged access tokens becomes mandatory. This measure ensures that the API remains in strict compliance with user privacy preferences and regulatory obligations, upholding the principles of transparency and user-centric data control. # Identifying the phone number from the access token This specification defines the "phoneNumber" field as optional in API requests because using a 3-legged access token the phone number can be uniquely identified by the token. ## Handling of phone number information: ### Optional phone number object for 3-legged tokens: When using a 3-legged access token, the phone number associated with the access token must be considered as the phone number for the API request. This means that the "phoneNumber" paramenter is not required in the request, and if it is included it must identify the same phone number. ### Validation mechanism: - The server will extract the phone number identification from the access token, if available. - If the API request additionally includes a "phoneNumber" parameter when using a 3-legged access token, the API will validate that the phone number identifier provided matches the one associated with the access token. - If there is a mismatch, the API will respond with a 403 `INVALID_TOKEN_CONTEXT` error, indicating that the device information in the request does not match the token. ### Error handling for unidentifiable devices: - If the "phoneNumber" parameter is not included in the request and the phone number information cannot be derived from the 3-legged access token, the server will return a 422 `UNIDENTIFIABLE_DEVICE` error. # API Documentation ## Details The CFS API is invoked by an API Consumer after the Consent Management flow.\ The API Consumer can request the API Producer for the status of the Unconditional Call Forwarding service using the unconditional-call-forwardings POST method. A boolean, with the information about the activation status of the call forwarding service, will be provided back via the UnconditionalCallForwardingSignal resource.\ The API Consumer can also request the API Producer for the generic status of the Call Forwarding service using the call-forwardings POST method. An array of strings with the information of the type of active call forwarding services will be provided back via the CallForwardingSignal resource.\ CFS API have to check the Call Forwarding Service status can be optionally defined with resource (CreateCallForwardingSignal) containing the phone number (PhoneNumber) to be checked. # FAQ's (FAQs will be added in a later version of the documentation) version: 0.2.0 license: name: Apache 2.0 url: https://www.apache.org/licenses/LICENSE-2.0.html x-camara-commonalities: 0.4.0 externalDocs: description: Product documentation at CAMARA url: https://github.com/camaraproject/CallForwardingSignal ############################################################################ # Servers # ############################################################################ servers: - url: "{apiRoot}/call-forwarding-signal/v0.2" variables: apiRoot: default: http://localhost:9091 description: API root, defined by the service provider, e.g. `api.example.com` or `api.example.com/somepath` ############################################################################ # Tags # ############################################################################ tags: - name: Unconditional Call Forwarding information retrieval description: Provides information on Unconditional Call Forwarding settings for the provided phone number (PhoneNumber) - name: Call Forwarding information retrieval description: Provides information on Call Forwarding settings for the provided phone number (PhoneNumber). ############################################################################ # Paths # ############################################################################ paths: /unconditional-call-forwardings: post: tags: - Unconditional Call Forwarding information retrieval security: - openId: - 'call-forwarding-signal:unconditional-call-forwardings:read' summary: Retrieve the information about the status of the unconditional call forwarding service on a phone number (PhoneNumber) description: This endpoint provides information about the status of the unconditional call forwarding, beeing active or not. operationId: retrieveUnconditionalCallForwarding parameters: - $ref: '#/components/parameters/x-correlator' requestBody: content: application/json: schema: $ref: '#/components/schemas/CreateCallForwardingSignal' required: true responses: '200': description: OK. headers: x-correlator: $ref: '#/components/headers/x-correlator' content: application/json: schema: $ref: '#/components/schemas/UnconditionalCallForwardingSignal' "400": $ref: "#/components/responses/Generic400" '404': $ref: '#/components/responses/Generic404' '500': $ref: '#/components/responses/Generic500' '504': $ref: '#/components/responses/Generic504' "401": $ref: "#/components/responses/Generic401" "403": $ref: "#/components/responses/Generic403" "409": $ref: "#/components/responses/Generic409" "415": $ref: "#/components/responses/Generic415" "422": $ref: "#/components/responses/Generic422" "429": $ref: "#/components/responses/Generic429" "503": $ref: "#/components/responses/Generic503" /call-forwardings: post: tags: - Call Forwarding information retrieval security: - openId: - 'call-forwarding-signal:call-forwardings:read' summary: Retrieve the information about the type of call forwarding service active on a phone number (PhoneNumber) description: This endpoint provides information about wich type of call forwarding service is active. More than one service can be active, e.g. conditional and unconditional. This endpoint exceeds the main scope of the CFS API, for this reason an error code 501 can be returned. operationId: retrieveCallForwarding parameters: - $ref: '#/components/parameters/x-correlator' requestBody: content: application/json: schema: $ref: '#/components/schemas/CreateCallForwardingSignal' required: true responses: '200': description: OK. headers: x-correlator: $ref: '#/components/headers/x-correlator' content: application/json: schema: $ref: '#/components/schemas/CallForwardingSignal' "400": $ref: "#/components/responses/Generic400" '404': $ref: '#/components/responses/Generic404' '500': $ref: '#/components/responses/Generic500' '504': $ref: '#/components/responses/Generic504' "401": $ref: "#/components/responses/Generic401" "403": $ref: "#/components/responses/Generic403" "409": $ref: "#/components/responses/Generic409" "415": $ref: "#/components/responses/Generic415" "422": $ref: "#/components/responses/Generic422" "429": $ref: "#/components/responses/Generic429" "501": $ref: "#/components/responses/Generic501" "503": $ref: "#/components/responses/Generic503" ############################################################################ # Components # ############################################################################ components: securitySchemes: openId: description: to support Consent Management type: openIdConnect openIdConnectUrl: https://example.com/.well-known/openid-configuration parameters: x-correlator: name: x-correlator in: header description: Correlation id for the different services schema: type: string headers: x-correlator: description: Correlation id for the different services schema: type: string ############################################################################ # Resources # ############################################################################ schemas: UnconditionalCallForwardingSignal: description: resource containing the information about the Unconditional Call Forwarding Service for the given phone number (PhoneNumber) type: object properties: active: type: boolean description: Indicates if the unconditional call forwarding service is active. CallForwardingSignal: description: resource containing the list of the Call Forwarding Services active for the given phone number (PhoneNumber). The possible states are, 'inactive' (no call forwarding service activated), 'unconditional' (call forwarded independently from the device status), 'conditional_busy' (call forwarded if the device is on an active call), 'conditional_unavailable' (call forwarded if the device is not available on the network), 'conditional_no_reply' (call forwarded if the device doesn't answer the incoming call). type: array items: type: string enum: - 'inactive' - 'unconditional' - 'conditional_busy' - 'conditional_unavailable' - 'conditional_no_reply' example: - 'unconditional' - 'conditional_busy' - 'conditional_no_reply' minItems: 1 ############################################################################ # Request # ############################################################################ CreateCallForwardingSignal: description: resource containing the phone number (PhoneNumber) regarding which the Call Forwarding Service must be checked type: object properties: phoneNumber: $ref: "#/components/schemas/PhoneNumber" ############################################################################ # Types # ############################################################################ PhoneNumber: description: A public identifier addressing a telephone subscription. In mobile networks it corresponds to the MSISDN (Mobile Station International Subscriber Directory Number). In order to be globally unique it has to be formatted in international format, according to E.164 standard, prefixed with '+'. type: string pattern: '^\+[1-9][0-9]{4,14}$' example: "+123456789" ############################################################################ # Responces # ############################################################################ ErrorInfo: description: error information type: object required: - status - code - message properties: status: type: integer description: HTTP status code returned along with this error response code: type: string description: Code given to this error message: type: string description: Detailed error description responses: Generic400: description: Problem with the client request headers: x-correlator: $ref: '#/components/headers/x-correlator' content: application/json: schema: $ref: '#/components/schemas/ErrorInfo' example: status: 400 code: INVALID_ARGUMENT message: Client specified an invalid argument, request body or query param Generic401: description: Authentication problem with the client request headers: x-correlator: $ref: '#/components/headers/x-correlator' content: application/json: schema: $ref: '#/components/schemas/ErrorInfo' example: status: 401 code: UNAUTHENTICATED message: Request not authenticated due to missing, invalid, or expired credentials Generic403: description: Client does not have sufficient permission headers: x-correlator: $ref: '#/components/headers/x-correlator' content: application/json: schema: $ref: '#/components/schemas/ErrorInfo' examples: PermissionDenied: value: status: 403 code: PERMISSION_DENIED message: Client does not have sufficient permissions to perform this action InvalidTokenContext: value: status: 403 code: INVALID_TOKEN_CONTEXT message: PhoneNumber parameter doesn't match the value from the access token context Generic404: description: The specified resource was not found headers: x-correlator: $ref: '#/components/headers/x-correlator' content: application/json: schema: $ref: '#/components/schemas/ErrorInfo' example: status: 404 code: CALL_FORWARDING.UNKNOWN_PHONE_NUMBER message: Call forwarding check can't be done because the phone number is unknown Generic409: description: Conflict headers: x-correlator: $ref: "#/components/headers/x-correlator" content: application/json: schema: $ref: "#/components/schemas/ErrorInfo" examples: GENERIC_409_ABORTED: description: Concurrency of processes of the same nature/scope value: status: 409 code: ABORTED message: Concurrency conflict. GENERIC_409_ALREADY_EXISTS: description: Trying to create an existing resource value: status: 409 code: ALREADY_EXISTS message: The resource that a client tried to create already exists. GENERIC_409_CONFLICT: description: Duplication of an existing resource value: status: 409 code: CONFLICT message: A specified resource duplicate entry found. Generic415: description: Unsupported Media Type headers: x-correlator: $ref: "#/components/headers/x-correlator" content: application/json: schema: $ref: "#/components/schemas/ErrorInfo" examples: GENERIC_415_UNSUPPORTED_MEDIA_TYPE: description: Payload format of the request is in an unsupported format by the Server. value: status: 415 code: UNSUPPORTED_MEDIA_TYPE message: The server refuses to accept the request because the payload format is in an unsupported format. Generic422: description: Unprocessable Content headers: x-correlator: $ref: "#/components/headers/x-correlator" content: application/json: schema: $ref: "#/components/schemas/ErrorInfo" examples: GENERIC_422_DEVICE_IDENTIFIERS_MISMATCH: description: Inconsistency between device identifiers not pointing to the same device value: status: 422 code: DEVICE_IDENTIFIERS_MISMATCH message: Provided device identifiers are not consistent. GENERIC_422_DEVICE_NOT_APPLICABLE: description: Service is not available for the provided device value: status: 422 code: DEVICE_NOT_APPLICABLE message: The service is not available for the provided device. GENERIC_422_UNIDENTIFIABLE_DEVICE: description: phone number not available neither from "phoneNumber" or from the access token. value: status: 422 code: UNIDENTIFIABLE_DEVICE message: phone number not defined Generic429: description: Too Many Requests headers: x-correlator: $ref: "#/components/headers/x-correlator" content: application/json: schema: $ref: "#/components/schemas/ErrorInfo" examples: GENERIC_429_QUOTA_EXCEEDED: description: Request is rejected due to exceeding a business quota limit. value: status: 429 code: QUOTA_EXCEEDED message: Either out of resource quota or reaching rate limiting. GENERIC_429_TOO_MANY_REQUESTS: description: API Server request limit is overpassed value: status: 429 code: TOO_MANY_REQUESTS message: Either out of resource quota or reaching rate limiting. Generic500: description: Server error headers: x-correlator: $ref: '#/components/headers/x-correlator' content: application/json: schema: $ref: '#/components/schemas/ErrorInfo' example: status: 500 code: INTERNAL message: Server error Generic501: description: Not Implemented headers: x-correlator: $ref: "#/components/headers/x-correlator" content: application/json: schema: $ref: "#/components/schemas/ErrorInfo" examples: GENERIC_501_NOT_IMPLEMENTED: description: Service not implemented. The use of this code should be avoided as far as possible to get the objective to reach aligned implementations value: status: 501 code: NOT_IMPLEMENTED message: This functionality is not implemented yet. Generic503: description: Service unavailable. Typically the server is down headers: x-correlator: $ref: '#/components/headers/x-correlator' content: application/json: schema: $ref: '#/components/schemas/ErrorInfo' example: status: 503 code: UNAVAILABLE message: Service unavailable Generic504: description: Request time exceeded. If it happens repeatedly, consider reducing the request complexity headers: x-correlator: $ref: '#/components/headers/x-correlator' content: application/json: schema: $ref: '#/components/schemas/ErrorInfo' example: status: 504 code: TIMEOUT message: Request timeout exceeded. Try later