Fix CAN ID and CAN Flag Transformation to SIL Kit API Enumerators

[VDanielEdwards]

Developer checklist (address before review)

• Documentation updated (public API changes only)

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Subject

What kind of changes does this pull request comprise?

• Feature
• Bug fix
• Documentation update
• other (please specify below)

Description

These changes fix an issue that was noticed by a user of SIL Kit in Issue 54.

In SocketCAN the can_id field of the struct can_frame also contains the EFF (IDE), RTR, and ERR flags in the upper three bits. These are however never masked when the frame is forwarded to SIL Kit.

Additionally, this PR drops Error-Frames (ERR flag set) and produces an error-level log message, since Error-Frames are currently not supported by SIL Kit.

Review assignments

• review code
• check new/modified tests (does it make sense? does it cover the functionality sufficiently?)
• run functional tests manually
• run specific setup (e.g., demos)
• other (please specify below)

Testing instructions (e.g., for specific setups)

You can verify that an issue existed by using cansend with an extended identifier, e.g., cansend vcan0 18FDE5FF#13140003FF006601 after bringing up the CAN device.

[VDanielEdwards]

Small addendum to the testing instructions: use the CAN demo from SIL Kit (in CanReader mode with the --async flag) to verify that the ID and the flags are correctly transformed.

[VDanielEdwards]

This issue is handled internally.