F5 iRule Example integrating HMAC

As I've said. I've just borrowed your brilliant idea... 😉

There are plenty of articles on how to use the [table] command to store and query arbitrary data (aka. build CMP-aware caches). But I don't believe you will find any information on the internet how to create TMM caches (aka. CMP-unaware) to avoid cross-TMM communication. I guess the only information you'll find on this topic is a little warning to not use this technique...

"Important: While it is possible to use the set command to modify a static global variable within the iRule and outside of the RULE_INIT event, such modifications will not be propagated to each TMM instance; they will be visible to only the TMM process on which the modification was made, resulting in inconsistent values for the static global variable across TMM instances. As a result, F5 strongly recommends that you do not update the value of any static global variable within the iRule." -SOL13033

... but still doing so would be very helpful for your HMAC verification to shrink the required CPU cycles to a great extend.

Let me see if I find some time in the evening to code you such an CMP-unaware cache. Its not that difficult to implement, so stay tuned...

Cheers, Kai