irmd: Bound the OAP replay cache

Replace the linked-list cache with three timestamp-generation hash
buckets, each capped at OAP_REPLAY_MAX entries.

A bucket is an open-addressed hash set whose slots count as live only
while slot.gen equals the bucket generation, so a stale bucket clears
in O(1) by bumping its generation instead of being scanned and pruned.

On overflow the cache fails closed - it rejects the header rather than
evicting the oldest entry. Under flood, dropping a genuine entry would
let that header be replayed, so refusing new entries is the safer
degradation than evict-oldest (fail-open) behaviour.

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

0 files changed, 0 insertions, 0 deletions