ktls: add method to track key updates #4364
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goatgoose
reviewed
Jan 17, 2024
Co-authored-by: Sam Clark <[email protected]>
goatgoose
approved these changes
Jan 17, 2024
maddeleine
approved these changes
Jan 17, 2024
goatgoose
approved these changes
Jan 18, 2024
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Description of changes:
Add key update count tracking. A customer interesting in TLS1.3 + ktls wants to measure how often they currently update their keys.
I think it's safe to cap the fields at 255. We really don't expect any connections to get anywhere near that many updates. When awslc saw that many, it was because of a bug :) 255 key updates would be enough for using AES to send 50TB of data with average sized records or 100TB with maximum sized records. If I bumped the fields up to uint16_t, it'd be 12PB/25PB.
Callouts:
I can see the argument that this method is pretty useless. If you don't control your clients, it's never going to be safe to assume that no clients will ever require a key update. But maybe the number is low enough that you're willing to take the availability hit? Minimally this should be unstable until we decide it's really necessary for ktls or find another use case.
Testing:
Unit tests.
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.