sys/suit/v4: switch to nanocbor

[kaspar030]

Contribution description

This PR changes suit/v4 to use nanocbor instead of tinycbor. The former was already used by suit's dependency libcose, causing two cbor parsers to be used.

Code size goes down from 75964b 74616b in nrf52dk.

Most of the work was done by @fjmolinas. I just fixed some bugs and put the diff into PR shape.

Testing procedure

WARNING the test will currently fail without #12408 and #12458 merged (same as on master).

Confirm the examples/suit_example test application runs successful.

Issues/PRs references

[fjmolinas]

Hmm.. I'm getting an error when validating the digest... investigating

iotboot_flashwrite: processing bytes 77376-77439
riotboot_flashwrite: processing bytes 77440-77479
riotboot: verifying digest at 0x20003577 (img at: 0x20800 size: 77480)
no handler found
handler returned <0
)suit_v4_parse() failed. res=-1
Timeout in expect script at "timeout=UPDATING_TIMEOUT)" (examples/suit_update/tests/01-run.py:71)

[kaspar030]

Hmm.. I'm getting an error when validating the digest... investigating

I'm getting the same now. I must have messed something up while polishing. Invastigating, too...

[kaspar030]

I think I got it. I've accidentally added an error return for the "no handler found" case.

[fjmolinas]

Test still working (if the correct source address is chosen), minor comments otherwise all good. ~1kB less as well :)

Image start address: 0x00001100
Header chksum: 0x69e1c0a7

[auto_init_netif] initializing ethos #0
----> ethos: hello received
Failed to send flush request: Operation not permitted
gnrc_uhcpc: Using 5 as border interface and 0 as wireless interface.
gnrc_uhcpc: only one interface found, skipping setup.
main(): This is RIOT! (Version: 2020.01-devel-301-gb91d5-pr-12562)
RIOT SUIT update example application
running from slot 0
TEST PASSED

[fjmolinas]

ACK, please squash!

[kaspar030]

• squashed

[benpicco]

btw what was the reason to convert SUIT to NanoCBOR instead of converting libcose to tinycbor?

[kaspar030]

nanocbor has a much nicer API and uses less code.

[benpicco]

It also has a lot more bugs and doesn't implement the full CBOR specification…