During a test with ~12000 established SAs it was noted that vici
related operations hung.
The operations took over 16 minutes to finish. The time was spent in
the vici message parser, which was assigning the message over and over
again, to get rid of the already parsed portions.
First fixed by cutting the consumed parts off without copying the message.
Runtime for ~12000 SAs is now around 20 seconds.
Further optimization brought the runtime down to roughly 1-2 seconds
by using an fd to read through the message variable.
Closesstrongswan/strongswan#103.
If a Quick mode is initiated for a CHILD_SA that is already installed
we can identify this situation and rekey the already installed CHILD_SA.
Otherwise we end up with several CHILD_SAs in state INSTALLED which
means multiple calls of child_updown are done. Unfortunately,
the deduplication code later does not call child_updown() (so up and down
were not even).
Closesstrongswan/strongswan#95.