Message Header Requirements

This section defines Software Low-Level Requirements (SW-LLR) for the SOME/IP Message Header parsing logic. All multi-byte fields use Big Endian (network byte order) encoding.

Overview

The SOME/IP message header is 16 bytes and contains the following fields:

  • Message ID (4 bytes): Service ID (16 bits) + Method ID (16 bits)

  • Length (4 bytes): Message length minus 8 bytes

  • Request ID (4 bytes): Client ID (16 bits) + Session ID (16 bits)

  • Protocol Version (1 byte)

  • Interface Version (1 byte)

  • Message Type (1 byte)

  • Return Code (1 byte)

Message ID Parsing

Requirement: Parse Message ID Field REQ_MSG_001
status: implemented
priority: high
satisfies: feat_req_someip_44, feat_req_someip_45, feat_req_someip_56, feat_req_someip_43, feat_req_someip_55, feat_req_someip_29, feat_req_someip_30

The software shall parse the Message ID field from bytes 0-3 of the SOME/IP header in Big Endian byte order.

Rationale: The Message ID is a 32-bit field that identifies the service and method/event.

Code Location: src/someip/message.cpp
Requirement: Extract Service ID from Message ID REQ_MSG_002
status: implemented
priority: high
satisfies: feat_req_someip_538, feat_req_someip_539, feat_req_someip_59, feat_req_someip_534, feat_req_someip_58, feat_req_someip_57

The software shall extract the Service ID from the upper 16 bits (bits 31-16) of the Message ID field.

Rationale: Service ID identifies the service offering the method.

Code Location: src/someip/message.cpp
Requirement: Extract Method ID from Message ID REQ_MSG_003
status: implemented
priority: high
satisfies: feat_req_someip_59, feat_req_someip_60, feat_req_someip_625, feat_req_someip_58

The software shall extract the Method ID from the lower 16 bits (bits 15-0) of the Message ID field.

Rationale: Method ID identifies the specific method or event.

Code Location: src/someip/message.cpp
Requirement: Validate Reserved Service ID 0x0000 REQ_MSG_004
status: implemented
priority: high
satisfies: feat_req_someip_627, feat_req_someip_816

The software shall reject messages with Service ID 0x0000 for normal (non-reserved) message processing, as this value is reserved.

Rationale: Service ID 0x0000 is reserved per specification.

Error Handling: Return E_UNKNOWN_SERVICE (0x02).

Code Location: src/someip/message.cpp
Requirement: Recognize SD Service ID 0xFFFF REQ_MSG_005
status: implemented
priority: high
satisfies: feat_req_someip_627, feat_req_someip_658

The software shall recognize Service ID 0xFFFF as the Service Discovery service identifier.

Rationale: SOME/IP-SD uses Service ID 0xFFFF for all SD messages.

Code Location: src/someip/message.cpp
Requirement: Accept Method IDs for Methods REQ_MSG_006
status: implemented
priority: high
satisfies: feat_req_someip_60, feat_req_someip_625, feat_req_someip_626

The software shall accept Method IDs in the range 0x0000 to 0x7FFF as valid method identifiers.

Rationale: Method IDs use the lower range of the 16-bit field.

Code Location: src/someip/message.cpp
Requirement: Accept Method IDs for Events REQ_MSG_007
status: implemented
priority: high
satisfies: feat_req_someip_67, feat_req_someip_625, feat_req_someip_626

The software shall accept Method IDs in the range 0x8000 to 0xFFFE as valid event identifiers.

Rationale: Events use the upper range of the Method ID field.

Code Location: src/someip/message.cpp
Requirement: Validate Reserved Method ID 0xFFFF REQ_MSG_008
status: implemented
priority: medium
satisfies: feat_req_someip_816, feat_req_someip_818

The software shall reject messages with Method ID 0xFFFF for normal message processing, as this value is reserved.

Rationale: Method ID 0xFFFF is reserved per specification.

Error Handling: Return E_UNKNOWN_METHOD (0x03).

Code Location: src/someip/message.cpp
Requirement: Error - Invalid Service ID Range REQ_MSG_004_E01
status: implemented
priority: high
satisfies: feat_req_someip_627, feat_req_someip_371

The software shall return error code E_UNKNOWN_SERVICE (0x02) when a message with an invalid or reserved Service ID is received.

Rationale: Proper error reporting for debugging and diagnostics.

Error Handling: Set return code to 0x02 in error response.

Code Location: src/someip/message.cpp
Requirement: Error - Log Invalid Service ID REQ_MSG_004_E02
status: implemented
priority: medium

The software shall log an error message containing the invalid Service ID value when a reserved or invalid Service ID is received.

Rationale: Diagnostics and troubleshooting support.

Error Handling: Log at ERROR level with Service ID value.

Code Location: src/someip/message.cpp

Length Field Parsing

Requirement: Parse Length Field REQ_MSG_010
status: implemented
priority: high
satisfies: feat_req_someip_77, feat_req_someip_76, feat_req_someip_34, feat_req_someip_35, feat_req_someip_36, feat_req_someip_38

The software shall parse the Length field from bytes 4-7 of the SOME/IP header in Big Endian byte order.

Rationale: The Length field indicates the size of the message excluding the first 8 bytes.

Code Location: src/someip/message.cpp
Requirement: Validate Length Field Calculation REQ_MSG_011
status: implemented
priority: high
satisfies: feat_req_someip_77

The software shall validate that the Length field value equals the total SOME/IP message size minus 8 bytes (Message ID + Length fields).

Rationale: Length field covers Request ID, Protocol Version, Interface Version, Message Type, Return Code, and payload.

Code Location: src/someip/message.cpp
Requirement: Minimum Length Value REQ_MSG_012
status: implemented
priority: high
satisfies: feat_req_someip_77, feat_req_someip_798

The software shall accept a minimum Length field value of 8 bytes, representing a message with header only and no payload.

Rationale: Minimum message contains 16-byte header (8 bytes in Length field calculation).

Code Location: src/someip/message.cpp
Requirement: Maximum Length for UDP Transport REQ_MSG_013
status: implemented
priority: high
satisfies: feat_req_someip_318, feat_req_someiptp_760, feat_req_someip_166

The software shall limit the maximum payload size to 1400 bytes for UDP transport without SOME/IP-TP, to fit within a single Ethernet frame.

Rationale: UDP binding limitation to avoid IP fragmentation.

Code Location: src/someip/message.cpp
Requirement: Error - Buffer Size Less Than Length REQ_MSG_014
status: implemented
priority: high
satisfies: feat_req_someip_77, feat_req_someip_798

The software shall reject messages where the received buffer size is less than the Length field value plus 8 bytes.

Rationale: Prevents buffer overread and ensures complete message.

Error Handling: Return E_MALFORMED_MESSAGE (0x09).

Code Location: src/someip/message.cpp
Requirement: Error - Length Less Than Minimum REQ_MSG_015
status: implemented
priority: high
satisfies: feat_req_someip_798

The software shall reject messages where the Length field value is less than 8 bytes.

Rationale: Minimum Length of 8 covers the remaining header fields.

Error Handling: Return E_MALFORMED_MESSAGE (0x09).

Code Location: src/someip/message.cpp
Requirement: Error - Return Malformed Message Code REQ_MSG_012_E01
status: implemented
priority: high

The software shall return error code E_MALFORMED_MESSAGE (0x09) when a message with an invalid Length field is received.

Rationale: Consistent error reporting for malformed messages.

Error Handling: Set return code to 0x09 in error response.

Code Location: src/someip/message.cpp
Requirement: Error - Log Invalid Length Value REQ_MSG_012_E02
status: implemented
priority: medium

The software shall log an error message containing the actual Length field value when an invalid Length is received.

Rationale: Diagnostics and troubleshooting support.

Error Handling: Log at ERROR level with Length value and expected range.

Code Location: src/someip/message.cpp
Requirement: Error - Truncated Message Detection REQ_MSG_014_E01
status: implemented
priority: high

The software shall detect truncated messages where the actual data received is shorter than indicated by the Length field.

Rationale: Ensures data integrity and prevents processing incomplete data.

Error Handling: Return E_MALFORMED_MESSAGE (0x09).

Code Location: src/someip/message.cpp
Requirement: Error - Buffer Overflow Protection REQ_MSG_014_E02
status: implemented
priority: high

The software shall validate the Length field before any payload access to prevent buffer overflow when Length exceeds actual buffer size.

Rationale: Security and safety requirement to prevent memory access violations.

Error Handling: Return E_MALFORMED_MESSAGE (0x09) without accessing payload.

Code Location: src/someip/message.cpp

Request ID Parsing

Requirement: Parse Request ID Field REQ_MSG_020
status: implemented
priority: high
satisfies: feat_req_someip_79, feat_req_someip_83, feat_req_someip_78, feat_req_someip_82, feat_req_someip_80

The software shall parse the Request ID field from bytes 8-11 of the SOME/IP header in Big Endian byte order.

Rationale: Request ID uniquely identifies a request for matching responses.

Code Location: src/someip/message.cpp
Requirement: Extract Client ID from Request ID REQ_MSG_021
status: implemented
priority: high
satisfies: feat_req_someip_83, feat_req_someip_699

The software shall extract the Client ID from the upper 16 bits (bits 31-16) of the Request ID field.

Rationale: Client ID identifies the requesting client.

Code Location: src/someip/message.cpp
Requirement: Extract Session ID from Request ID REQ_MSG_022
status: implemented
priority: high
satisfies: feat_req_someip_83, feat_req_someip_88

The software shall extract the Session ID from the lower 16 bits (bits 15-0) of the Request ID field.

Rationale: Session ID tracks individual requests within a session.

Code Location: src/someip/message.cpp
Requirement: Session ID Zero - Disabled Session Handling REQ_MSG_023
status: implemented
priority: medium
satisfies: feat_req_someip_700

The software shall interpret Session ID 0x0000 as an indication that session handling is disabled for this communication.

Rationale: Some implementations may not use session handling.

Code Location: src/someip/message.cpp
Requirement: Session ID Wrap-Around Handling REQ_MSG_024
status: implemented
priority: high
satisfies: feat_req_someip_649, feat_req_someip_677

The software shall implement Session ID wrap-around such that after 0xFFFF, the next Session ID shall be 0x0001, skipping 0x0000.

Rationale: 0x0000 is reserved for disabled session handling.

Code Location: src/core/session_manager.cpp
Requirement: Client ID Zero - Reserved for SD REQ_MSG_025
status: implemented
priority: medium
satisfies: feat_req_someip_699

The software shall recognize Client ID 0x0000 as reserved for Service Discovery messages.

Rationale: SD messages use Client ID 0x0000 per specification.

Code Location: src/someip/message.cpp
Requirement: Error - Duplicate Session ID Detection REQ_MSG_024_E01
status: implemented
priority: medium

The software shall detect duplicate Session IDs when session handling is enabled and an active session with the same ID exists.

Rationale: Prevents request/response mismatch.

Error Handling: Log warning and handle based on configuration.

Code Location: src/core/session_manager.cpp
Requirement: Error - Session ID Sequence Validation REQ_MSG_024_E02
status: implemented
priority: medium

The software shall optionally validate that Session IDs are received in expected sequence (incrementing, with wrap-around handling).

Rationale: Helps detect lost or reordered messages.

Error Handling: Log warning; accept message but flag sequence gap.

Code Location: src/core/session_manager.cpp

Protocol Version Parsing

Requirement: Parse Protocol Version Field REQ_MSG_030
status: implemented
priority: high
satisfies: feat_req_someip_90, feat_req_someip_89

The software shall parse the Protocol Version field from byte 12 of the SOME/IP header.

Rationale: Protocol Version identifies the SOME/IP protocol version.

Code Location: src/someip/message.cpp
Requirement: Validate Protocol Version Value REQ_MSG_031
status: implemented
priority: high
satisfies: feat_req_someip_90, feat_req_someip_703

The software shall validate that the Protocol Version field value equals 0x01 for SOME/IP version 1.

Rationale: Current SOME/IP specification uses Protocol Version 1.

Code Location: src/someip/message.cpp
Requirement: Error - Reject Invalid Protocol Version REQ_MSG_032
status: implemented
priority: high
satisfies: feat_req_someip_90, feat_req_someip_371

The software shall reject messages where the Protocol Version field does not equal 0x01.

Rationale: Ensures compatibility with expected protocol version.

Error Handling: Return E_WRONG_PROTOCOL_VERSION (0x07).

Code Location: src/someip/message.cpp
Requirement: Error - Return Wrong Protocol Version Code REQ_MSG_033
status: implemented
priority: high
satisfies: feat_req_someip_90, feat_req_someip_371

The software shall return error code E_WRONG_PROTOCOL_VERSION (0x07) when a message with an unsupported Protocol Version is received.

Rationale: Standard error code for protocol version mismatch.

Error Handling: Set return code to 0x07 in error response.

Code Location: src/someip/message.cpp
Requirement: Error - Log Unknown Protocol Version REQ_MSG_032_E01
status: implemented
priority: medium

The software shall log an error message containing the received Protocol Version value when an unsupported version is detected.

Rationale: Diagnostics for version compatibility issues.

Error Handling: Log at ERROR level with received version value.

Code Location: src/someip/message.cpp
Requirement: Error - Discard Message on Protocol Mismatch REQ_MSG_032_E02
status: implemented
priority: high

The software shall discard the entire message without further processing when the Protocol Version is invalid.

Rationale: Cannot reliably parse a message with unknown protocol version.

Error Handling: Do not process payload; optionally send error response.

Code Location: src/someip/message.cpp

Interface Version Parsing

Requirement: Parse Interface Version Field REQ_MSG_040
status: implemented
priority: high
satisfies: feat_req_someip_92, feat_req_someip_91, feat_req_someip_93

The software shall parse the Interface Version field from byte 13 of the SOME/IP header.

Rationale: Interface Version indicates the service interface version.

Code Location: src/someip/message.cpp
Requirement: Pass Interface Version to Application REQ_MSG_041
status: implemented
priority: high
satisfies: feat_req_someip_92

The software shall pass the Interface Version value to the application layer for service-specific version validation.

Rationale: Interface version compatibility is application-specific.

Code Location: src/someip/message.cpp
Requirement: Error - Interface Version Mismatch Handling REQ_MSG_042
status: implemented
priority: medium
satisfies: feat_req_someip_371

The software shall return error code E_WRONG_INTERFACE_VERSION (0x08) when the application rejects the Interface Version.

Rationale: Standard error code for interface version mismatch.

Error Handling: Set return code to 0x08 in error response.

Code Location: src/someip/message.cpp
Requirement: Error - Log Interface Version Mismatch REQ_MSG_042_E01
status: implemented
priority: medium

The software shall log an error message containing both the expected and received Interface Version values when a mismatch occurs.

Rationale: Diagnostics for interface version compatibility issues.

Error Handling: Log at WARNING level with both version values.

Code Location: src/someip/message.cpp

Message Type Parsing

Requirement: Parse Message Type Field REQ_MSG_050
status: implemented
priority: high
satisfies: feat_req_someip_95, feat_req_someip_94, feat_req_someip_684

The software shall parse the Message Type field from byte 14 of the SOME/IP header.

Rationale: Message Type determines message semantics and processing.

Code Location: src/someip/message.cpp
Requirement: Accept REQUEST Message Type REQ_MSG_051
status: implemented
priority: high
satisfies: feat_req_someip_95, feat_req_someip_141, feat_req_someip_329

The software shall accept Message Type 0x00 (REQUEST) for request/response method calls.

Rationale: Standard message type for RPC requests.

Code Location: src/someip/message.cpp
Requirement: Accept REQUEST_NO_RETURN Message Type REQ_MSG_052
status: implemented
priority: high
satisfies: feat_req_someip_95, feat_req_someip_345

The software shall accept Message Type 0x01 (REQUEST_NO_RETURN) for fire-and-forget method calls.

Rationale: Standard message type for one-way requests.

Code Location: src/someip/message.cpp
Requirement: Accept NOTIFICATION Message Type REQ_MSG_053
status: implemented
priority: high
satisfies: feat_req_someip_95, feat_req_someip_354

The software shall accept Message Type 0x02 (NOTIFICATION) for event notifications and field updates.

Rationale: Standard message type for events.

Code Location: src/someip/message.cpp
Requirement: Accept RESPONSE Message Type REQ_MSG_054
status: implemented
priority: high
satisfies: feat_req_someip_95, feat_req_someip_141, feat_req_someip_338

The software shall accept Message Type 0x80 (RESPONSE) for successful method responses.

Rationale: Standard message type for RPC responses.

Code Location: src/someip/message.cpp
Requirement: Accept ERROR Message Type REQ_MSG_055
status: implemented
priority: high
satisfies: feat_req_someip_95, feat_req_someip_106, feat_req_someip_107, feat_req_someip_727

The software shall accept Message Type 0x81 (ERROR) for error responses to method calls.

Rationale: Standard message type for error responses.

Code Location: src/someip/message.cpp
Requirement: Detect TP Flag in Message Type REQ_MSG_056
status: implemented
priority: high
satisfies: feat_req_someip_761, feat_req_someiptp_765

The software shall detect the TP flag (bit 5, value 0x20) in the Message Type field to identify SOME/IP-TP segmented messages.

Rationale: TP flag indicates the message is a segment of a larger message.

Code Location: src/someip/message.cpp
Requirement: Accept REQUEST_ACK Message Type REQ_MSG_057
status: implemented
priority: medium
satisfies: feat_req_someip_95, feat_req_someip_142

The software shall accept Message Type 0x40 (REQUEST_ACK) for acknowledgment of received requests.

Rationale: Optional acknowledgment message type.

Code Location: src/someip/message.cpp
Requirement: Accept RESPONSE_ACK Message Type REQ_MSG_058
status: implemented
priority: medium
satisfies: feat_req_someip_95, feat_req_someip_142

The software shall accept Message Type 0xC0 (RESPONSE_ACK) for acknowledgment of received responses.

Rationale: Optional acknowledgment message type.

Code Location: src/someip/message.cpp
Requirement: Accept ERROR_ACK Message Type REQ_MSG_059
status: implemented
priority: medium
satisfies: feat_req_someip_95, feat_req_someip_142

The software shall accept Message Type 0xC1 (ERROR_ACK) for acknowledgment of received error responses.

Rationale: Optional acknowledgment message type.

Code Location: src/someip/message.cpp
Requirement: Accept TP_REQUEST Message Type REQ_MSG_060_TP
status: implemented
priority: high
satisfies: feat_req_someip_761, feat_req_someiptp_765

The software shall accept Message Type 0x20 (TP_REQUEST) for segmented request messages.

Rationale: TP variant of REQUEST message type.

Code Location: src/someip/message.cpp
Requirement: Accept TP_REQUEST_NO_RETURN Message Type REQ_MSG_061_TP
status: implemented
priority: high
satisfies: feat_req_someip_761, feat_req_someiptp_765

The software shall accept Message Type 0x21 (TP_REQUEST_NO_RETURN) for segmented fire-and-forget messages.

Rationale: TP variant of REQUEST_NO_RETURN message type.

Code Location: src/someip/message.cpp
Requirement: Accept TP_NOTIFICATION Message Type REQ_MSG_062_TP
status: implemented
priority: high
satisfies: feat_req_someip_761, feat_req_someiptp_765

The software shall accept Message Type 0x22 (TP_NOTIFICATION) for segmented notification messages.

Rationale: TP variant of NOTIFICATION message type.

Code Location: src/someip/message.cpp
Requirement: Error - Reject Unknown Message Type REQ_MSG_063
status: implemented
priority: high
satisfies: feat_req_someip_95, feat_req_someip_721

The software shall reject messages with Message Type values not defined in the SOME/IP specification.

Rationale: Unknown message types cannot be processed correctly.

Error Handling: Return E_WRONG_MESSAGE_TYPE (0x0A).

Code Location: src/someip/message.cpp
Requirement: Error - Return Wrong Message Type Code REQ_MSG_064
status: implemented
priority: high
satisfies: feat_req_someip_95, feat_req_someip_371

The software shall return error code E_WRONG_MESSAGE_TYPE (0x0A) when a message with an unknown Message Type is received.

Rationale: Standard error code for message type errors.

Error Handling: Set return code to 0x0A in error response.

Code Location: src/someip/message.cpp
Requirement: Error - Log Unknown Message Type REQ_MSG_063_E01
status: implemented
priority: medium

The software shall log an error message containing the unknown Message Type value when an invalid type is received.

Rationale: Diagnostics for protocol compatibility issues.

Error Handling: Log at ERROR level with Message Type value in hex.

Code Location: src/someip/message.cpp
Requirement: Error - Reserved Message Type Bits Validation REQ_MSG_063_E02
status: implemented
priority: medium

The software shall validate that reserved bit combinations in the Message Type field are not used.

Rationale: Reserved values may be used in future protocol versions.

Error Handling: Return E_WRONG_MESSAGE_TYPE (0x0A).

Code Location: src/someip/message.cpp

Return Code Parsing

Requirement: Parse Return Code Field REQ_MSG_070
status: implemented
priority: high
satisfies: feat_req_someip_144, feat_req_someip_371, feat_req_someip_143, feat_req_someip_369, feat_req_someip_683

The software shall parse the Return Code field from byte 15 of the SOME/IP header.

Rationale: Return Code indicates the result of a request.

Code Location: src/someip/message.cpp
Requirement: Validate Return Code Zero for Requests REQ_MSG_071
status: implemented
priority: high
satisfies: feat_req_someip_144, feat_req_someip_371

The software shall validate that REQUEST, REQUEST_NO_RETURN, and NOTIFICATION messages have Return Code 0x00 (E_OK).

Rationale: Request messages shall always have Return Code E_OK.

Code Location: src/someip/message.cpp
Requirement: Accept Standard Return Codes REQ_MSG_072
status: implemented
priority: high
satisfies: feat_req_someip_371

The software shall accept Return Codes in the range 0x00 to 0x5F as defined in the SOME/IP specification.

Rationale: Standard return codes are defined for common error cases.

Code Location: src/someip/message.cpp
Requirement: Accept E_OK Return Code REQ_MSG_073
status: implemented
priority: high
satisfies: feat_req_someip_371

The software shall accept Return Code 0x00 (E_OK) indicating successful operation.

Rationale: Standard success code.

Code Location: src/someip/message.cpp
Requirement: Accept E_NOT_OK Return Code REQ_MSG_074
status: implemented
priority: high
satisfies: feat_req_someip_371

The software shall accept Return Code 0x01 (E_NOT_OK) indicating an unspecified error.

Rationale: Generic error code.

Code Location: src/someip/message.cpp
Requirement: Accept E_UNKNOWN_SERVICE Return Code REQ_MSG_075
status: implemented
priority: high
satisfies: feat_req_someip_371, feat_req_someip_816

The software shall accept Return Code 0x02 (E_UNKNOWN_SERVICE) indicating the requested service is not available.

Rationale: Standard error for unknown service.

Code Location: src/someip/message.cpp
Requirement: Accept E_UNKNOWN_METHOD Return Code REQ_MSG_076
status: implemented
priority: high
satisfies: feat_req_someip_371, feat_req_someip_816

The software shall accept Return Code 0x03 (E_UNKNOWN_METHOD) indicating the requested method is not available.

Rationale: Standard error for unknown method.

Code Location: src/someip/message.cpp
Requirement: Accept E_NOT_READY Return Code REQ_MSG_077
status: implemented
priority: high
satisfies: feat_req_someip_371

The software shall accept Return Code 0x04 (E_NOT_READY) indicating the service is not ready.

Rationale: Standard error for service not ready.

Code Location: src/someip/message.cpp
Requirement: Accept E_NOT_REACHABLE Return Code REQ_MSG_078
status: implemented
priority: high
satisfies: feat_req_someip_371

The software shall accept Return Code 0x05 (E_NOT_REACHABLE) indicating the service is not reachable.

Rationale: Standard error for unreachable service.

Code Location: src/someip/message.cpp
Requirement: Accept E_TIMEOUT Return Code REQ_MSG_079
status: implemented
priority: high
satisfies: feat_req_someip_371

The software shall accept Return Code 0x06 (E_TIMEOUT) indicating a timeout occurred.

Rationale: Standard error for timeout.

Code Location: src/someip/message.cpp
Requirement: Accept E_MALFORMED_MESSAGE Return Code REQ_MSG_080
status: implemented
priority: high
satisfies: feat_req_someip_371

The software shall accept Return Code 0x09 (E_MALFORMED_MESSAGE) indicating a malformed message was received.

Rationale: Standard error for malformed messages.

Code Location: src/someip/message.cpp
Requirement: Error - Non-Zero Return Code in Request REQ_MSG_071_E01
status: implemented
priority: high
satisfies: feat_req_someip_371, feat_req_someip_597

The software shall reject REQUEST messages where the Return Code field is not 0x00.

Rationale: Request messages must have E_OK return code.

Error Handling: Return E_MALFORMED_MESSAGE (0x09).

Code Location: src/someip/message.cpp
Requirement: Error - Unknown Return Code Handling REQ_MSG_072_E01
status: implemented
priority: medium

The software shall accept unknown Return Codes (values > 0x5F) but log a warning for diagnostic purposes.

Rationale: Forward compatibility with future return codes.

Error Handling: Log warning with unknown Return Code value.

Code Location: src/someip/message.cpp
Requirement: Error - Log Invalid Return Code in Request REQ_MSG_071_E02
status: implemented
priority: medium

The software shall log an error message when a REQUEST message is received with a non-zero Return Code.

Rationale: Diagnostics for protocol violations.

Error Handling: Log at ERROR level with Return Code value.

Code Location: src/someip/message.cpp

Endianness Requirements

Requirement: Big Endian Header Fields REQ_MSG_090
status: implemented
priority: high
satisfies: feat_req_someip_42, feat_req_someip_44, feat_req_someip_45, feat_req_someip_675, feat_req_someip_41

The software shall interpret all multi-byte header fields (Message ID, Length, Request ID) in Big Endian (network byte order).

Rationale: SOME/IP specifies Big Endian for header fields.

Code Location: src/someip/message.cpp
Requirement: Host to Network Byte Order on Serialize REQ_MSG_091
status: implemented
priority: high
satisfies: feat_req_someip_42, feat_req_someip_675

The software shall convert multi-byte header fields from host byte order to Big Endian (network byte order) during serialization.

Rationale: Ensures correct wire format regardless of host endianness.

Code Location: src/someip/message.cpp
Requirement: Network to Host Byte Order on Deserialize REQ_MSG_092
status: implemented
priority: high
satisfies: feat_req_someip_42, feat_req_someip_675

The software shall convert multi-byte header fields from Big Endian (network byte order) to host byte order during deserialization.

Rationale: Ensures correct interpretation regardless of host endianness.

Code Location: src/someip/message.cpp
Requirement: Single Byte Fields No Conversion REQ_MSG_093
status: implemented
priority: low
satisfies: feat_req_someip_42

The software shall not perform byte order conversion on single-byte fields (Protocol Version, Interface Version, Message Type, Return Code).

Rationale: Single-byte fields have no endianness concern.

Code Location: src/someip/message.cpp

Header Validation Composite Requirements

Requirement: Complete Header Validation REQ_MSG_100
status: implemented
priority: high
satisfies: feat_req_someip_44, feat_req_someip_45, feat_req_someip_721

The software shall validate the complete SOME/IP header by checking:

  1. Buffer size >= 16 bytes (minimum header size)

  2. Length field >= 8 and consistent with buffer size

  3. Protocol Version == 0x01

  4. Message Type is a known value

  5. Return Code constraints based on Message Type

Rationale: Complete validation ensures message integrity.

Code Location: src/someip/message.cpp
Requirement: Error - Null Buffer Pointer REQ_MSG_100_E01
status: implemented
priority: high

The software shall safely reject deserialization requests where the input buffer pointer is null.

Rationale: Prevents null pointer dereference.

Error Handling: Return error immediately without dereferencing.

Code Location: src/someip/message.cpp
Requirement: Error - Buffer Too Small for Header REQ_MSG_100_E02
status: implemented
priority: high

The software shall reject buffers smaller than 16 bytes, as they cannot contain a complete SOME/IP header.

Rationale: Minimum header size is 16 bytes.

Error Handling: Return E_MALFORMED_MESSAGE (0x09).

Code Location: src/someip/message.cpp
Requirement: Error - Empty Buffer Handling REQ_MSG_100_E03
status: implemented
priority: high

The software shall safely reject empty buffers (size 0) during deserialization.

Rationale: Empty buffers cannot contain valid messages.

Error Handling: Return E_MALFORMED_MESSAGE (0x09).

Code Location: src/someip/message.cpp

Identifier Ranges

Requirement: Service Instance ID Support REQ_MSG_110
status: implemented
priority: high
satisfies: feat_req_someip_542, feat_req_someip_543, feat_req_someip_544, feat_req_someip_579

The software shall support Service Instance IDs as 16-bit unsigned integers. Instance IDs 0x0000 (reserved) and 0xFFFF (all instances) shall not be used for a specific service instance.

Rationale: Service Instance IDs enable multiple instances of the same service to coexist.

Code Location: include/sd/sd_types.h (ServiceInstance::instance_id), include/sd/sd_message.h (ServiceEntry)
Requirement: Service ID Uniqueness REQ_MSG_111
status: implemented
priority: medium
satisfies: feat_req_someip_541

The software shall enforce that different services within the same vehicle have different Service IDs. Attempting to register a duplicate Service ID shall return an error; the existing registration remains unchanged.

Rationale: Unique Service IDs prevent routing ambiguity in the vehicle network.

Code Location: include/someip/types.h, src/sd/sd_server.cpp
Requirement: Non-SOME/IP Service ID 0xFFFE REQ_MSG_112
status: draft
priority: medium
satisfies: feat_req_someip_624

The software shall recognize Service ID 0xFFFE as the identifier for non-SOME/IP services, enabling interoperability with other protocols.

Rationale: Service ID 0xFFFE enables interoperability with non-SOME/IP protocol stacks.

Code Location: include/someip/types.h
Requirement: Eventgroup ID Support REQ_MSG_113
status: implemented
priority: high
satisfies: feat_req_someip_545, feat_req_someip_546, feat_req_someip_547, feat_req_someip_670

The software shall support Eventgroup IDs as 16-bit unsigned integers. Different eventgroups of a service shall have different Eventgroup IDs.

Rationale: Eventgroup IDs enable selective event subscription per service.

Code Location: include/sd/sd_types.h (EventGroup::eventgroup_id), include/events/event_types.h

RPC Communication Patterns

Requirement: Request/Response Header Construction REQ_MSG_114
status: implemented
priority: high
satisfies: feat_req_someip_329, feat_req_someip_338, feat_req_someip_327, feat_req_someip_328

The software shall support constructing request headers (Message Type 0x00, Return Code 0x00) and response headers (Message Type 0x80/0x81) with fields copied from the corresponding request.

Rationale: Correct header construction ensures responses are matched to requests.

Code Location: src/rpc/rpc_client.cpp (RpcClientImpl::call_method), src/rpc/rpc_server.cpp (send_success_response, send_error_response)
Requirement: Fire-and-Forget No Response REQ_MSG_115
status: implemented
priority: high
satisfies: feat_req_someip_345, feat_req_someip_348, feat_req_someip_344

The software shall support fire-and-forget messages (Message Type 0x01) that shall not trigger a response message. Error handling for fire-and-forget shall be implemented by the application.

Rationale: Fire-and-forget reduces overhead for messages that do not require confirmation.

Code Location: src/someip/message.cpp, src/rpc/rpc_server.cpp
Requirement: Response IP Address Mapping REQ_MSG_116
status: implemented
priority: high
satisfies: feat_req_someip_49, feat_req_someip_46, feat_req_someip_48

The software shall ensure response and error messages swap the source and destination IP addresses and port numbers relative to the request.

Rationale: IP/port swapping ensures responses reach the originating client.

Code Location: src/rpc/rpc_server.cpp (send_success_response), src/transport/endpoint.h
Requirement: Payload Field Extraction REQ_MSG_117
status: implemented
priority: high
satisfies: feat_req_someip_165, feat_req_someip_164

The software shall extract the payload field from the SOME/IP message following the 16-byte header.

Rationale: Payload extraction provides application data for further processing.

Code Location: src/someip/message.cpp (Message::deserialize)
Requirement: Session Handling for Request/Response REQ_MSG_118
status: implemented
priority: high
satisfies: feat_req_someip_669

The software shall use session handling (incrementing Session ID) for all request/response method calls.

Rationale: Session handling for R/R enables detection of lost or reordered responses.

Code Location: src/core/session_manager.cpp, src/rpc/rpc_client.cpp
Requirement: Session Handling for Events REQ_MSG_119
status: implemented
priority: medium
satisfies: feat_req_someip_667

When event session handling is enabled via configuration, the software shall use session handling for events, notification events, and fire-and-forget methods and increment session IDs per event group using the next_session_id_ mechanism.

Rationale: Session handling for events enables detection of missed notifications.

Code Location: src/events/event_publisher.cpp (next_session_id_++)
Requirement: Client ID Configurable Prefix REQ_MSG_120
status: implemented
priority: medium
satisfies: feat_req_someip_701

The software shall support configuring a Client ID prefix or fixed value to enable vehicle-wide unique Client IDs.

Rationale: Configurable Client ID prefix ensures vehicle-wide uniqueness.

Code Location: src/rpc/rpc_client.cpp (RpcClientImpl constructor, client_id_)

Event and Field Support

Requirement: Event Delivery to All Subscribers REQ_MSG_121a
status: implemented
priority: high
satisfies: feat_req_someip_354, feat_req_someip_351, feat_req_someip_352

The software shall deliver published events to all clients that are currently subscribed to the corresponding eventgroup.

Rationale: Delivering events to all subscribers ensures no subscriber misses a notification.

Code Location: src/events/event_publisher.cpp (publish_event, subscriptions_)
Requirement: Suppress Events to Non-Subscribers REQ_MSG_121b
status: implemented
priority: high
satisfies: feat_req_someip_353, feat_req_someip_807

The software shall not deliver events to clients that have not subscribed to the corresponding eventgroup.

Rationale: Suppressing events to non-subscribers reduces unnecessary network traffic and CPU usage.

Code Location: src/events/event_publisher.cpp (publish_event subscription check)
Requirement: Event Delivery After Unsubscribe REQ_MSG_121c
status: implemented
priority: high
satisfies: feat_req_someip_355, feat_req_someip_356

The software shall stop delivering events to a client immediately after the client unsubscribes from the eventgroup.

Rationale: Immediate suppression after unsubscribe prevents unwanted event processing.

Code Location: src/events/event_publisher.cpp (subscriptions_ removal)
Requirement: Selective Event Sending REQ_MSG_122
status: implemented
priority: medium
satisfies: feat_req_someip_804, feat_req_someip_806

The software should support sending events to a subset of subscribed clients, controlled by the application.

Rationale: Selective sending reduces bandwidth when not all subscribers need every event.

Code Location: src/events/event_subscriber.cpp (set_event_filters), include/events/event_types.h (EventFilter)
Requirement: Field Getter Support REQ_MSG_123
status: implemented
priority: high
satisfies: feat_req_someip_631, feat_req_someip_633, feat_req_someip_630, feat_req_someip_637

The software shall support field getters as request/response calls with an empty request payload and the field value in the response.

Rationale: Field getters allow clients to read current field values on demand.

Code Location: src/events/event_subscriber.cpp (request_field), include/events/event_subscriber.h
Requirement: Field Setter Support REQ_MSG_124
status: implemented
priority: high
satisfies: feat_req_someip_631, feat_req_someip_634

The software shall support field setters as request/response calls with the desired value in the request and the actual set value in the response.

Rationale: Field setters allow clients to update field values with server-side validation.

Code Location: src/events/event_publisher.cpp (publish_field), include/events/event_publisher.h
Requirement: Field Notifier Support REQ_MSG_125
status: implemented
priority: high
satisfies: feat_req_someip_631, feat_req_someip_635

The software shall support field notifiers that send notification event messages when the field value changes.

Rationale: Field notifiers push value changes to interested clients without polling.

Code Location: src/events/event_publisher.cpp (publish_field on change)
Requirement: No Field Without Accessors REQ_MSG_126
status: implemented
priority: medium
satisfies: feat_req_someip_632

The software shall not allow a field without at least one accessor (getter, setter, or notifier).

Rationale: A field without any accessor serves no purpose and indicates a design error.

Code Location: include/events/event_publisher.h

Error Handling Extensions

Requirement: No Error for Fire-and-Forget REQ_MSG_127
status: implemented
priority: high
satisfies: feat_req_someip_654

The software shall not return error messages for fire-and-forget methods.

Rationale: Fire-and-forget methods have no sender to receive error responses.

Code Location: src/rpc/rpc_server.cpp (message type check before error response)
Requirement: No Error for Events REQ_MSG_128
status: implemented
priority: high
satisfies: feat_req_someip_597

The software shall not return error messages for events and notifications.

Rationale: Events/notifications are unidirectional and have no requester to receive errors.

Code Location: src/rpc/rpc_server.cpp (message type check before error response)
Requirement: Error Header Copy REQ_MSG_129
status: implemented
priority: high
satisfies: feat_req_someip_655

The software shall copy the Message ID, Request ID, and Interface Version from the request into the error response message.

Rationale: Copying header fields enables the requester to correlate errors with requests.

Code Location: src/rpc/rpc_server.cpp (send_error_response copies header fields)
Requirement: No Error Response to Error Messages REQ_MSG_130
status: implemented
priority: high
satisfies: feat_req_someip_704

The software shall not send error responses to messages that already carry an error (return code not equal to 0x00).

Rationale: Sending errors in response to errors would create infinite error loops.

Code Location: src/rpc/rpc_server.cpp (return code check before error response)
Requirement: Return Code Configuration REQ_MSG_131
status: implemented
priority: medium
satisfies: feat_req_someip_598, feat_req_someip_1092

The software shall support configurable generation and handling of return codes.

Rationale: Configurable return codes support application-specific error semantics.

Code Location: include/someip/types.h (ReturnCode enum), src/someip/types.cpp
Requirement: Exception Message Type 0x81 REQ_MSG_132a
status: implemented
priority: medium
satisfies: feat_req_someip_101, feat_req_someip_726, feat_req_someip_421

The software shall use Message Type 0x81 (ERROR) for exception messages when exception message support is configured.

Rationale: Exception messages provide richer error information than a return code alone.

Code Location: src/rpc/rpc_server.cpp (send_error_response)
Requirement: Exception Message Payload REQ_MSG_132b
status: implemented
priority: medium
satisfies: feat_req_someip_422, feat_req_someip_423, feat_req_someip_426

When exception messages are configured, the software shall include error detail information in the ERROR message payload. When not configured, errors shall be transported via Return Code in regular RESPONSE messages.

Rationale: The payload carries details (error string, context) not expressible in a return code.

Code Location: src/someip/message.cpp, src/rpc/rpc_server.cpp
Requirement: Error Check Step 1 - Protocol Version REQ_MSG_133a
status: implemented
priority: high
satisfies: feat_req_someip_719, feat_req_someip_721

The software shall check the Protocol Version field first in the error handling sequence. Messages with invalid Protocol Version shall be rejected immediately without checking subsequent fields.

Rationale: Checking Protocol Version first prevents misinterpreting messages from incompatible versions.

Code Location: src/someip/message.cpp (has_valid_message_type)
Requirement: Error Check Step 2 - Message Type REQ_MSG_133b
status: implemented
priority: high
satisfies: feat_req_someip_717, feat_req_someip_718

The software shall check the Message Type field after Protocol Version validation. Messages with unknown Message Type shall be rejected before service or method validation.

Rationale: Checking Message Type before service/method prevents dispatching to handlers that cannot process it.

Code Location: src/someip/message.cpp (has_valid_message_type)
Requirement: Error Check Step 3 - Service and Method Validation REQ_MSG_133c
status: implemented
priority: high
satisfies: feat_req_someip_366, feat_req_someip_364, feat_req_someip_365, feat_req_someip_720

The software shall check Service ID and Method ID after Message Type validation. Unknown Service ID shall return E_UNKNOWN_SERVICE (0x02), unknown Method ID shall return E_UNKNOWN_METHOD (0x03).

Rationale: Service/method validation reports specific errors to help clients correct their requests.

Code Location: src/rpc/rpc_server.cpp
Requirement: Service Instance Port Multiplexing REQ_MSG_134
status: implemented
priority: high
satisfies: feat_req_someip_648, feat_req_someip_444, feat_req_someip_446

The software shall multiplex messages belonging to different service instances by the transport protocol port on the server side.

Rationale: Port-based multiplexing allows multiple service instances to share infrastructure.

Code Location: src/sd/sd_server.cpp (offer_service per instance), include/sd/sd_types.h
Requirement: Error Message Handling REQ_MSG_135
status: implemented
priority: high
satisfies: feat_req_someip_367, feat_req_someip_727, feat_req_someip_366, feat_req_someip_368

The software shall support two error handling mechanisms: the Return Code field in all messages, and the Exception Message type for detailed error information.

Rationale: Supporting both return codes and exception messages gives flexibility for different error reporting needs.

Code Location: src/someip/message.cpp, src/rpc/rpc_server.cpp

Header Informational References

Requirement: IP Address and Port Mapping REQ_MSG_140
status: implemented
priority: medium
satisfies: feat_req_someip_47, feat_req_someip_313, feat_req_someip_314

The software shall parse SOME/IP messages transported over IP/UDP or IP/TCP with correct IP address and port extraction.

Rationale: IP/port extraction is fundamental for correct transport-layer routing.

Code Location: src/transport/udp_transport.cpp, src/transport/endpoint.h
Requirement: Publish/Subscribe Support REQ_MSG_141
status: implemented
priority: medium
satisfies: feat_req_someip_361, feat_req_someip_360

The software shall support publish/subscribe handling as specified in SOME/IP-SD.

Rationale: Publish/subscribe decouples event producers from consumers.

Code Location: src/events/event_publisher.cpp, src/sd/sd_client.cpp
Requirement: Error - Invalid Service Instance ID REQ_MSG_110_E01
status: implemented
priority: high

The software shall reject Service Instance ID 0x0000 (reserved) and 0xFFFF (wildcard) when used as a specific instance identifier.

Rationale: Reserved Instance IDs have special semantics and cannot identify a specific instance.

Error Handling: Return error and log invalid Instance ID value.

Code Location: include/sd/sd_types.h, src/sd/sd_server.cpp
Requirement: Error - Duplicate Eventgroup ID REQ_MSG_113_E01
status: implemented
priority: medium

The software shall reject duplicate Eventgroup IDs within the same service.

Rationale: Duplicate Eventgroup IDs cause subscription routing ambiguity.

Error Handling: Return error and log the duplicate Eventgroup ID.

Code Location: include/events/event_types.h, src/events/event_publisher.cpp
Requirement: Error - Response Without Matching Request REQ_MSG_114_E01
status: implemented
priority: high

The software shall discard response messages that do not match any pending request.

Rationale: Orphan responses may indicate protocol errors or stale replies.

Error Handling: Discard message, log warning with Request ID.

Code Location: src/rpc/rpc_client.cpp
Requirement: Error - Response Timeout REQ_MSG_114_E02
status: implemented
priority: high

The software shall report a timeout error when no response is received within the configured timeout for a request/response call.

Rationale: Timeout handling prevents indefinite blocking on lost responses.

Error Handling: Invoke error callback with E_TIMEOUT.

Code Location: src/rpc/rpc_client.cpp (session_manager timeout)
Requirement: Error - Payload Size Exceeds Maximum REQ_MSG_117_E01
status: implemented
priority: high

The software shall reject messages whose payload size exceeds the maximum allowed for the transport type.

Rationale: Oversized payloads cause fragmentation or transport failures.

Error Handling: Return E_MALFORMED_MESSAGE and log payload size vs maximum.

Code Location: src/someip/message.cpp
Requirement: Error - Session ID Zero in Active Session REQ_MSG_118_E01
status: implemented
priority: medium

The software shall log a warning when Session ID 0x0000 is received in a context where session handling is expected to be active.

Rationale: Session ID 0x0000 indicates disabled session handling, which may be unexpected.

Error Handling: Log warning; process message based on configuration.

Code Location: src/core/session_manager.cpp
Requirement: Error - Client ID Conflict REQ_MSG_120_E01
status: implemented
priority: medium

The software shall detect and report Client ID conflicts when two clients attempt to use the same Client ID.

Rationale: Client ID conflicts cause request/response matching failures.

Error Handling: Return error and log conflicting Client ID value.

Code Location: src/rpc/rpc_client.cpp
Requirement: Error - Event Publish to No Subscribers REQ_MSG_121_E01
status: implemented
priority: low

The software shall handle event publication with zero subscribers gracefully without error.

Rationale: Zero subscribers is a normal transient condition during service startup.

Error Handling: No error; event is silently discarded.

Code Location: src/events/event_publisher.cpp
Requirement: Error - Field Getter Not Available REQ_MSG_123_E01
status: implemented
priority: medium

The software shall return E_UNKNOWN_METHOD when a field getter is called but not configured for the field.

Rationale: Unconfigured getters indicate client-side configuration errors.

Error Handling: Return E_UNKNOWN_METHOD in error response.

Code Location: src/events/event_subscriber.cpp
Requirement: Error - Field Setter Validation Failure REQ_MSG_124_E01
status: implemented
priority: medium

The software shall return the current (unchanged) field value when a setter validation fails.

Rationale: The response always carries the actual field value, enabling clients to detect rejected changes.

Error Handling: Return E_NOT_OK with current field value in response payload.

Code Location: src/events/event_publisher.cpp
Requirement: Error - Interface Version Zero REQ_MSG_040_E01
status: implemented
priority: medium

The software shall log a warning when Interface Version 0x00 is received, as it may indicate an uninitialized field.

Rationale: Version 0 is unusual and may indicate a programming error.

Error Handling: Log warning, process message normally.

Code Location: src/someip/message.cpp
Requirement: Error - Request ID All Zeros REQ_MSG_020_E01
status: implemented
priority: medium

The software shall log a warning when a non-SD message has Request ID 0x00000000.

Rationale: All-zero Request ID in non-SD messages may indicate initialization error.

Error Handling: Log warning with message details.

Code Location: src/someip/message.cpp
Requirement: Error - Message Length Overflow REQ_MSG_010_E01
status: implemented
priority: high

The software shall reject messages with Length values that would cause integer overflow or exceed implementation limits.

Rationale: Maximum length protection prevents denial-of-service from crafted length values.

Error Handling: Return E_MALFORMED_MESSAGE (0x09), log declared length.

Code Location: src/someip/message.cpp
Requirement: Error - Serialization Output Buffer Full REQ_MSG_090_E01
status: implemented
priority: high

The software shall reject serialization when the output buffer cannot hold the complete message.

Rationale: Partial serialization produces corrupted wire-format data.

Error Handling: Return BUFFER_OVERFLOW error code, no partial write.

Code Location: src/someip/message.cpp
Requirement: Error - Duplicate Field Notifier Registration REQ_MSG_125_E01
status: implemented
priority: low

The software shall handle duplicate notifier registration for the same field by replacing the existing notifier with the new one. The previous notifier shall be released to prevent resource leaks.

Rationale: Duplicate registration without cleanup causes dangling references.

Error Handling: Replace existing notifier; release the old one.

Code Location: src/events/event_publisher.cpp
Requirement: Error - Response Message Type for Non-Request REQ_MSG_054_E01
status: implemented
priority: medium

The software shall log a warning when a RESPONSE message is received for a method configured as fire-and-forget.

Rationale: RESPONSE for F&F methods indicates a sender misconfiguration.

Error Handling: Log warning, discard response.

Code Location: src/rpc/rpc_client.cpp
Requirement: Error - Notification With Non-Zero Return Code REQ_MSG_053_E01
status: implemented
priority: medium

The software shall reject NOTIFICATION messages with non-zero Return Code.

Rationale: Notifications must have Return Code E_OK per the SOME/IP specification.

Error Handling: Return E_MALFORMED_MESSAGE (0x09).

Code Location: src/someip/message.cpp
Requirement: Error - Event Publish After Shutdown REQ_MSG_121_E02
status: implemented
priority: medium

The software shall reject event publication attempts after the publisher has been stopped.

Rationale: Publishing after shutdown may cause use-after-free or dangling references.

Error Handling: Return NOT_READY error.

Code Location: src/events/event_publisher.cpp

Traceability

Implementation Files

  • include/someip/message.h - Message class definition

  • include/someip/types.h - Type definitions

  • src/someip/message.cpp - Message implementation

  • src/someip/types.cpp - Type implementations

  • src/core/session_manager.cpp - Session ID management

Test Files

  • tests/test_message.cpp - Message unit tests