Solved Problem

This PR adds support for the Mavlink Mission opaque ID as defined in mavlink/mavlink#2012. It is based on the earlier implementation for the mission checksum support in #18418, but the mission checksum in Mavlink will be deprecated in mavlink/mavlink#2010.

Solution

• Add an opaque Id for the mission, geofence and rally points. The opaque id is based on a Crc32 checksum as in the implementation in Implement mission checksum #18418
• Opaque id is send from the System in the MISSION_COUNT on download. On upload, the opaque id is sent on the final MISSION_ACK
• The opaque Id is also streamed continuously in the MISSION_CURRENT message, such that a GCS can detect plan changes.
• The opaque id internally also replaces the mission counter, as those serves the same purpose.

Changelog Entry

For release notes:

Feature: Add Support for Mavlink mission opaque Id.

Alternatives

Opqaue id could also just be a counter instead of the Crc32. The hash implementation has the advantage that on loading the same mission (e.g. also from a file) should result in the same Id and thus the potentially multiple connected GCS does not need to download it again. Also it would allow for the feature, that a GCS does not need to download the mission on first connection if the old stored mission and opaque id is the same.

Test coverage

• Unit/integration test: SITL testing by observing the mavlink message sent from the system.

Context

• Before this can be merged, the respective mavlink PR should be merged