#3 Separate "SNMP IP" & "routing iface IP", MAC-only search...

[Jim Klimov]

* Added feature: search only by MAC address, without an IP (and check each
switch only once)

* Added feature: accept MAC addresses in various formats -
Standard XX:XX:XX:XX:XX:XX
Windows XX-XX-XX-XX-XX-XX
Hewlett XXXXXX-XXXXXX
Cisco XXXX.XXXX.XXXX
Unseparated XXXXXXXXXXXX
Standard and Windows formats may have 0 to 2 hex digits in each component.
Less than 2 digits are zero-padded, more are processed as an error.
MAC adresses are "tolower()ed" as to easily copy them to switch telnet
sessions (i.e. for Cisco IOS "sh mac- | in maca.ddre.ss01")

* Added feature: for ROUTER config entries we can have a separate "SNMP IP"
(old position of IP address) and "Routing interface IP" (optional sixth
position). For future format expansions, an empty string ("") can be
specified (if a seventh parameter is added, but then it is mandatory).
This feature allows to run SNMP queries against an IP address accessible
from the management station, but request info about an interface in
the specific subnet (used for ARP lookups to find the target host's MAC).

* Added feature: ROUTER configurations can also (like SWITCHes) use textual
host names for "SNMP IP" and/or "Routing interface IP". Previously the
"SNMP IP == Routing interface IP" could only be a numeric IP address.
Now resolvable names can be used and forged i.e. via /etc/hosts, so
that the same sdig.conf can be used from mgmt stations in different
subnets accessing different "SNMP IP" hosts.
Useful against inter-subnet firewalls ;)
The resolved IP value is reported at debug_level >= 1.

* Added feature: print user-defined interface descriptions (ifAlias) from
SNMP lookups, if available, in curly braces. The ifDesc value is almost
useless, since many switches (HP, Cisco) fill it with port's long name.

NOTES

Code has been aligned with the SourceForge trunk version (unreleased sdig-044) used as the base.
File layout differs from sdig-0.43, so the patch is not directly applicable to the released tar.gz source.
It can be backported (reverse of my forward-porting last night ;) ) - but not worth the effort if you can
do "svn checkout". Parallelized SNMP search in SVN trunk sdig-0.44 seems cool ;)

"Config" version is bumped to "0.45cvs".

[Jim Klimov]

Patch with the changes to sdig-0.45cvs