* correctly prepare a buffer to obtain interface description from a kernel and
truncate long description instead of dropping it altogether and
spamming logs;
* skip calling strlen() for each description and each SNMP request
for MIB-II/ifXTable's ifAlias.
* teach bsnmpd to allocate memory dynamically for interface descriptions
to decrease memory usage for common case and not to break
if long description occurs;
PR: 217763
Reviewed by: harti and others
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D16459
Instead of constantly calling the mibII_idle function when the server is not busy
call the function only once every 10 seconds to avoid bsnmpd constantly doing
gettimeofday syscalls. Make the idle polling interval confugurable via
begemotIfDataPoll.
Reported and tested by: misho (at) aitbg (dot) com
Oked by: harti
MFC after: 1 week
