lldp fix for nxos6 #372 (#375)

* first part of fix for #372

makes lldp stop using lldpLocPortDesc directly but maps it to a function

start framework to allow nexus.pm to overwrite that function for nx-os6

* second part of fix for #372

make nx-os 6 return lldpLocPortId for lldp_lport_desc

* munge_null and whitespace nits

lib/SNMP/Info/LLDP.pm

@@ -55,10 +55,13 @@ $VERSION = '3.70';
 );
 
 %FUNCS = (
-
     # LLDP-MIB::lldpLocManAddrTable
     'lldp_lman_addr' => 'lldpLocManAddrIfId',
 
+    # LLDP-MIB::LldpLocPortEntry
+    'lldp_lport_id'   => 'lldpLocPortId',
+    'lldp_lport_desc' => 'lldpLocPortDesc',
+
     # LLDP-MIB::lldpRemTable
     'lldp_rem_id_type'  => 'lldpRemChassisIdSubtype',
     'lldp_rem_id'       => 'lldpRemChassisId',
@@ -92,6 +95,8 @@ $VERSION = '3.70';
     'lldp_rem_sysname'   => \&SNMP::Info::munge_null,
     'lldp_rem_sysdesc'   => \&SNMP::Info::munge_null,
     'lldp_rem_port_desc' => \&SNMP::Info::munge_null,
+    'lldp_lport_id'      => \&SNMP::Info::munge_null,
+    'lldp_lport_desc'    => \&SNMP::Info::munge_null,
     'lldp_sys_cap'       => \&SNMP::Info::munge_bits,
     'lldp_rem_sys_cap'   => \&SNMP::Info::munge_bits,
     'lldp_rem_cap_spt'   => \&SNMP::Info::munge_bits,
@@ -146,7 +151,11 @@ sub lldp_if {
         # ifAlias because using cross ref with description is correct
         # behavior according to the LLDP-MIB. Some devices (eg H3C gear)
         # seem to use ifAlias though.
-        my $lldp_desc = $lldp->lldpLocPortDesc($port);
+        # snmp::info #372 -> to make things even more complex some devices
+        # have different behaviour depending on os version (nx-os 6 vs 7)
+        # so we made this a function to allow overrides in more specific
+        # modules
+        my $lldp_desc = $lldp->lldp_lport_desc($port);
         my $desc      = $lldp_desc->{$port};
 
         # If cross reference is successful use it, otherwise stick with

lib/SNMP/Info/Layer3/Nexus.pm

@@ -40,7 +40,7 @@ our ($VERSION, %GLOBALS, %MIBS, %FUNCS, %MUNGE);
 @SNMP::Info::Layer3::Nexus::ISA = qw/
 	SNMP::Info::Layer3::CiscoSwitch
 	Exporter
-	/;
+/;
 
 @SNMP::Info::Layer3::Nexus::EXPORT_OK = qw//;
 
@@ -53,14 +53,14 @@ $VERSION = '3.70';
 # The @ISA order should be reverse of these orders.
 
 %MIBS = (
-	%SNMP::Info::Layer3::CiscoSwitch::MIBS,
+    %SNMP::Info::Layer3::CiscoSwitch::MIBS,
-	'CISCO-ENTITY-VENDORTYPE-OID-MIB'   => 'cevMIBObjects',
+    'CISCO-ENTITY-VENDORTYPE-OID-MIB'   => 'cevMIBObjects',
-  'CISCO-CONTEXT-MAPPING-MIB'         => 'cContextMappingMIBObjects',
+    'CISCO-CONTEXT-MAPPING-MIB'         => 'cContextMappingMIBObjects',
 );
 
 %GLOBALS = (
-	%SNMP::Info::Layer3::CiscoSwitch::GLOBALS,
+    %SNMP::Info::Layer3::CiscoSwitch::GLOBALS,
-	'mac' => 'dot1dBaseBridgeAddress',
+    'mac' => 'dot1dBaseBridgeAddress',
 );
 
 %FUNCS = (
@@ -137,6 +137,21 @@ sub model {
 	return $model;
 }
 
+# nx-os 6 seems to swap the data of lldpLocPortDesc with that of
+# lldpLocPortId, so remap it to make the main lldp module happy.
+# nx-os 7 behaves as expected.
+sub lldp_lport_desc {
+    my $nexus         = shift;
+    my $osver         = $nexus->os_ver();
+
+    if (defined ($osver)) {
+        if ($osver =~ /^6.*/) {
+            return $nexus->SUPER::lldp_lport_id();
+        }
+    }
+    return $nexus->SUPER::lldp_lport_desc();
+}
+
 # Reported version 6.x of NX-OS doesn't use the IPv4 address as index
 # override methods in ipAddrTable
 sub ip_table {
@@ -377,6 +392,12 @@ Gives broadcast address for IP table entry.
 
 (C<ipAdEntBcastAddr>)
 
+=item $nexus->lldp_lport_desc()
+
+On nx-os 6 only this will return data from C<lldpLocPortId> instead of
+the expected C<lldpLocPortDesc>. For all other nx-os versions uses the
+function from L<SNMP::Info::LLDP>.
+
 =back
 
 =head2 Globals imported from SNMP::Info::Layer3::CiscoSwitch