refactor snmp_connect to handle versions and device classes

Netdisco/lib/App/Netdisco/Util/DiscoverAndStore.pm

@@ -95,7 +95,7 @@ sub store_device {
       $device->$property( $snmp->$property );
   }
 
-  $device->snmp_class( $snmp->class );
+  $device->snmp_class( $snmp->device_type );
   $device->last_discover(\'now()');
 
   schema('netdisco')->txn_do(sub {

Netdisco/lib/App/Netdisco/Util/SNMP.pm

@@ -60,6 +60,30 @@ sub _snmp_connect_generic {
   # get device details from db
   my $device = get_device($ip);
 
+  # TODO: only supporing v2c at the moment
+  my %snmp_args = (
+    DestHost => $device->ip,
+    Retries => (setting('snmpretries') || 2),
+    Timeout => (setting('snmptimeout') || 1000000),
+    MibDirs => [ _build_mibdirs() ],
+    IgnoreNetSNMPConf => 1,
+    Debug => ($ENV{INFO_TRACE} || 0),
+  );
+
+  # TODO: add version force support
+  # use existing SNMP version or try 2, 1
+  my @versions = (($device->snmp_ver || setting('snmpver') || 2));
+  push @versions, 1;
+
+  # use existing or new device class
+  my @classes = ('SNMP::Info');
+  if ($device->snmp_class) {
+    unshift @classes, $device->snmp_class;
+  }
+  else {
+    $snmp_args{AutoSpecity} = 1;
+  }
+
   # get the community string(s)
   my $comm_type = pop;
   my @communities = @{ setting($comm_type) || []};
@@ -67,36 +91,61 @@ sub _snmp_connect_generic {
     if length $device->snmp_comm
        and length $comm_type and $comm_type eq 'community';
 
-  # TODO: only supporing v2c at the moment
-  my %snmp_args = (
-    DestHost => $device->ip,
-    Version => ($device->snmp_ver || setting('snmpver') || 2),
-    Retries => (setting('snmpretries') || 2),
-    Timeout => (setting('snmptimeout') || 1000000),
-    MibDirs => [ _build_mibdirs() ],
-    AutoSpecify => 1,
-    IgnoreNetSNMPConf => 1,
-    Debug => ($ENV{INFO_TRACE} || 0),
-  );
-
   my $info = undef;
-  my $last_comm = 0;
-  COMMUNITY: foreach my $c (@communities) {
-      next unless defined $c and length $c;
-      try {
-          $info = SNMP::Info->new(%snmp_args, Community => $c);
-          ++$last_comm if (
-            $info
-            and (not defined $info->error)
-            and length $info->uptime
-          );
-      };
-      last COMMUNITY if $last_comm;
+  VERSION: foreach my $ver (@versions) {
+      next unless length $ver;
+
+      CLASS: foreach my $class (@classes) {
+          next unless length $class;
+
+          COMMUNITY: foreach my $comm (@communities) {
+              next unless length $comm;
+
+              $info = _try_connect($ver, $class, $comm, \%snmp_args)
+                and last VERSION;
+          }
+      }
   }
 
   return $info;
 }
 
+sub _try_connect {
+  my ($ver, $class, $comm, $snmp_args) = @_;
+  my $info = undef;
+
+  try {
+      debug
+        sprintf '[%s] try_connect with ver: %s, class: %s, comm: %s',
+        $snmp_args->{DestHost}, $ver, $class, $comm;
+      eval "require $class";
+
+      $info = $class->new(%$snmp_args, Version => $ver, Community => $comm);
+      undef $info unless (
+        (not defined $info->error)
+        and length $info->uptime
+        and ($info->layers or $info->description)
+        and $info->class
+      );
+
+      # first time a device is discovered, re-instantiate into specific class
+      if ($info and $info->device_type ne $class) {
+          $class = $info->device_type;
+          debug
+            sprintf '[%s] try_connect with ver: %s, new class: %s, comm: %s',
+            $snmp_args->{DestHost}, $ver, $class, $comm;
+
+          eval "require $class";
+          $info = $class->new(%$snmp_args, Version => $ver, Community => $comm);
+      }
+  }
+  catch {
+      debug $_;
+  };
+
+  return $info;
+}
+
 sub _build_mibdirs {
   return map { dir(setting('mibhome'), $_) }
              @{ setting('mibdirs') || [] };