generator/C: Don't parse messages outside CRC_EXTRA #990
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I have been wondering for a while why I sometimes see MAVLink
components "appear" with random sysid/compid when I leave a system
running for some time.
Today I finally caught the bytes of such a case, the offending bytes
were:
{253, 0, 1, 0, 0, 3, 1, 1, 42, 0, 185, 186,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
This is msgid 10753 from sysid 3, compid 1 with payload len 0.
It's presumably signed, hence the trailing zeros.
It turns out the msgid is way out of the CRC_EXTRA table and hence the
mavlink_get_msg_entry(msgid) function returns NULL.
In that case 0 is ignored and we carry on parsing.
My suggestion is to reset parsing when we don't know the CRC_EXTRA of
the message to avoid flagging noise as a valid message.
Signed-off-by: Julian Oes <[email protected]>
|
Any comment @peterbarker? FYI @auturgy |
|
@peterbarker Is probably at the conference and @auturgy is away this week. So probably they won't get back to you this week. |
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I have been wondering for a while why I sometimes see MAVLink components "appear" with random sysid/compid when I leave a system running for some time.
Today I finally caught the bytes of such a case, the offending bytes were:
{253, 0, 1, 0, 0, 3, 1, 1, 42, 0, 185, 186, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};This is msgid 10753 from sysid 3, compid 1 with payload len 0. It's presumably signed, hence the trailing zeros.
It turns out the msgid is way out of the CRC_EXTRA table and hence the mavlink_get_msg_entry(msgid) function returns NULL. In that case 0 is ignored and we carry on parsing.
My suggestion is to reset parsing when we don't know the CRC_EXTRA of the message to avoid flagging noise as a valid message.