Yue Cao claims that current host rate limiting of challenge ACKS
(RFC 5961) could leak enough information to allow a patient attacker
to hijack TCP sessions. He will soon provide details in an academic
paper.
Backports upstream commit 75ff39ccc1bd5d3c455b6822ab09e533c551f758
to the used LEDE kernel versions.
Signed-off-by: Jo-Philipp Wich <jo@mein.io>