Which algorithm is used for IP fragmentation ID?

[ian ivy]

Hello everyone. It is my first post on this mailinglist.

As we know in FreeBSD there is the pseudo random
number generator (PRNG) for random IP fragmentation ID.
It is available when "net.inet.ip.random_id" sysctl variable is
set to 1 (default 0). I would like to know, which algorithm (X2,
X3 or A0 or another one) is used in FreeBSD 8.1-RELEASE or
better in 8 branch?

Which algorithm is used in FreeBSD for packet filtering
(IP packet normalization, or e.g. scrub on $ext_if ... random-id
for the PF ruleset), pfsync interface protocol and (if the kernel  flag
"net.inet.ip.random_id" is set to 1) for "regular" IP traffic
(with TCP/UDP), IP multicast routing... etc?


Best regards!