313 lines
		
	
	
		
			9.4 KiB
		
	
	
	
		
			Perl
		
	
	
	
	
	
			
		
		
	
	
			313 lines
		
	
	
		
			9.4 KiB
		
	
	
	
		
			Perl
		
	
	
	
	
	
| package App::Netdisco::Transport::SNMP;
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| 
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| use Dancer qw/:syntax :script/;
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| use Dancer::Plugin::DBIC 'schema';
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| 
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| use App::Netdisco::Util::SNMP 'get_communities';
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| use App::Netdisco::Util::Device 'get_device';
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| use App::Netdisco::Util::Permission ':all';
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| 
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| use SNMP::Info;
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| use Try::Tiny;
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| use Module::Load ();
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| use Path::Class 'dir';
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| use NetAddr::IP::Lite ':lower';
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| 
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| use base 'Dancer::Object::Singleton';
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| 
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| =head1 NAME
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| 
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| App::Netdisco::Transport::SNMP
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| 
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| =head1 DESCRIPTION
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| 
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| Singleton for SNMP connections. Returns cached L<SNMP::Info> instance for a
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| given device IP, or else undef. All methods are class methods, for example:
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| 
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|  App::Netdisco::Transport::SNMP->reader_for( ... );
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| 
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| =cut
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| 
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| __PACKAGE__->attributes(qw/ readers writers /);
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| 
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| sub init {
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|   my ( $class, $self ) = @_;
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|   $self->readers( {} );
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|   $self->writers( {} );
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|   return $self;
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| }
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| 
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| =head1 reader_for( $ip, $useclass? )
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| 
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| Given an IP address, returns an L<SNMP::Info> instance configured for and
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| connected to that device. The IP can be any on the device, and the management
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| interface will be connected to.
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| 
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| If the device is known to Netdisco and there is a cached SNMP community
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| string, that community will be tried first, and then other community strings
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| from the application configuration will be tried.
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| 
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| If C<$useclass> is provided, it will be used as the L<SNMP::Info> device
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| class instead of the class in the Netdisco database.
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| 
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| Returns C<undef> if the connection fails.
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| 
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| =cut
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| 
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| sub reader_for {
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|   my ($class, $ip, $useclass) = @_;
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|   my $device = get_device($ip) or return undef;
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|   my $readers = $class->instance->readers or return undef;
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|   return $readers->{$device->ip} if exists $readers->{$device->ip};
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|   debug sprintf 'snmp reader cache warm: [%s]', $device->ip;
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|   return ($readers->{$device->ip}
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|     = _snmp_connect_generic('read', $device, $useclass));
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| }
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| 
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| =head1 test_connection( $ip )
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| 
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| Similar to C<reader_for> but will use the literal IP address passed, and does
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| not support specifying the device class. The purpose is to test the SNMP
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| connectivity to the device before a renumber.
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| 
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| Attempts to have no side effect, however there will be a stored SNMP
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| authentication hint (tag) in the database if the connection is successful.
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| 
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| Returns C<undef> if the connection fails.
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| 
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| =cut
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| 
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| sub test_connection {
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|   my ($class, $ip) = @_;
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|   my $addr = NetAddr::IP::Lite->new($ip) or return undef;
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|   # avoid renumbering to localhost loopbacks
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|   return undef if $addr->addr eq '0.0.0.0'
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|                   or check_acl_no($addr->addr, 'group:__LOCAL_ADDRESSES__');
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|   my $device = schema('netdisco')->resultset('Device')
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|     ->new_result({ ip => $addr->addr }) or return undef;
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|   my $readers = $class->instance->readers or return undef;
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|   return $readers->{$device->ip} if exists $readers->{$device->ip};
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|   debug sprintf 'snmp reader cache warm: [%s]', $device->ip;
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|   return ($readers->{$device->ip} = _snmp_connect_generic('read', $device));
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| }
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| 
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| =head1 writer_for( $ip, $useclass? )
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| 
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| Same as C<reader_for> but uses the read-write community strings from the
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| application configuration file.
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| 
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| Returns C<undef> if the connection fails.
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| 
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| =cut
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| 
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| sub writer_for {
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|   my ($class, $ip, $useclass) = @_;
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|   my $device = get_device($ip) or return undef;
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|   my $writers = $class->instance->writers or return undef;
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|   return $writers->{$device->ip} if exists $writers->{$device->ip};
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|   debug sprintf 'snmp writer cache warm: [%s]', $device->ip;
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|   return ($writers->{$device->ip}
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|     = _snmp_connect_generic('write', $device, $useclass));
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| }
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| 
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| sub _snmp_connect_generic {
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|   my ($mode, $device, $useclass) = @_;
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|   $mode ||= 'read';
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| 
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|   my %snmp_args = (
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|     AutoSpecify => 0,
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|     DestHost => $device->ip,
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|     # 0 is falsy. Using || with snmpretries equal to 0 will set retries to 2.
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|     # check if the setting is 0. If not, use the default value of 2.
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|     Retries => (setting('snmpretries') || setting('snmpretries') == 0 ? 0 : 2),
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|     Timeout => (setting('snmptimeout') || 1000000),
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|     NonIncreasing => (setting('nonincreasing') || 0),
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|     BulkWalk => ((defined setting('bulkwalk_off') && setting('bulkwalk_off'))
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|                  ? 0 : 1),
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|     BulkRepeaters => (setting('bulkwalk_repeaters') || 20),
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|     MibDirs => [ _build_mibdirs() ],
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|     IgnoreNetSNMPConf => 1,
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|     Debug => ($ENV{INFO_TRACE} || 0),
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|     DebugSNMP => ($ENV{SNMP_TRACE} || 0),
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|   );
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| 
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|   # an override for bulkwalk
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|   $snmp_args{BulkWalk} = 0 if check_acl_no($device, 'bulkwalk_no');
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| 
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|   # further protect against buggy Net-SNMP, and disable bulkwalk
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|   if ($snmp_args{BulkWalk}
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|       and ($SNMP::VERSION eq '5.0203' || $SNMP::VERSION eq '5.0301')) {
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| 
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|       warning sprintf
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|         "[%s] turning off BulkWalk due to buggy Net-SNMP - please upgrade!",
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|         $device->ip;
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|       $snmp_args{BulkWalk} = 0;
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|   }
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| 
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|   # get the community string(s)
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|   my @communities = get_communities($device, $mode);
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| 
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|   # which SNMP versions to try and in what order
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|   my @versions =
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|     ( check_acl_no($device->ip, 'snmpforce_v3') ? (3)
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|     : check_acl_no($device->ip, 'snmpforce_v2') ? (2)
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|     : check_acl_no($device->ip, 'snmpforce_v1') ? (1)
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|     : (reverse (1 .. (setting('snmpver') || 3))) );
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| 
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|   # use existing or new device class
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|   my @classes = ($useclass || 'SNMP::Info');
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|   if ($device->snmp_class and not $useclass) {
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|       unshift @classes, $device->snmp_class;
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|   }
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| 
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|   my $info = undef;
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|   COMMUNITY: foreach my $comm (@communities) {
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|       next unless $comm;
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| 
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|       VERSION: foreach my $ver (@versions) {
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|           next unless $ver;
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| 
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|           next if $ver eq 3 and exists $comm->{community};
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|           next if $ver ne 3 and !exists $comm->{community};
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| 
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|           CLASS: foreach my $class (@classes) {
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|               next unless $class;
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| 
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|               my %local_args = (%snmp_args, Version => $ver);
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|               $info = _try_connect($device, $class, $comm, $mode, \%local_args,
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|                 ($useclass ? 0 : 1) );
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|               last COMMUNITY if $info;
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|           }
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|       }
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|   }
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| 
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|   return $info;
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| }
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| 
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| sub _try_connect {
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|   my ($device, $class, $comm, $mode, $snmp_args, $reclass) = @_;
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|   my %comm_args = _mk_info_commargs($comm);
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|   my $debug_comm = '<hidden>';
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|   if ($ENV{ND2_SHOW_COMMUNITY} || $ENV{SHOW_COMMUNITY}) {
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|     $debug_comm = ($comm->{community} ||
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|       (sprintf 'v3:%s:%s/%s', ($comm->{user},
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|                               ($comm->{auth}->{proto} || 'noAuth'),
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|                               ($comm->{priv}->{proto} || 'noPriv'))) );
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|   }
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|   my $info = undef;
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| 
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|   try {
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|       debug
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|         sprintf '[%s] try_connect with ver: %s, class: %s, comm: %s',
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|         $snmp_args->{DestHost}, $snmp_args->{Version}, $class, $debug_comm;
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|       Module::Load::load $class;
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| 
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|       $info = $class->new(%$snmp_args, %comm_args) or return;
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|       $info = ($mode eq 'read' ? _try_read($info, $device, $comm)
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|                                : _try_write($info, $device, $comm));
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| 
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|       # first time a device is discovered, re-instantiate into specific class
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|       if ($reclass and $info and $info->device_type ne $class) {
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|           $class = $info->device_type;
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|           debug
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|             sprintf '[%s] try_connect with ver: %s, new class: %s, comm: %s',
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|             $snmp_args->{DestHost}, $snmp_args->{Version}, $class, $debug_comm;
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| 
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|           Module::Load::load $class;
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|           $info = $class->new(%$snmp_args, %comm_args);
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|       }
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|   }
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|   catch {
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|       debug $_;
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|   };
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| 
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|   return $info;
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| }
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| 
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| sub _try_read {
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|   my ($info, $device, $comm) = @_;
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| 
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|   return undef unless (
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|     (not defined $info->error)
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|     and defined $info->uptime
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|     and ($info->layers or $info->description)
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|     and $info->class
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|   );
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| 
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|   $device->in_storage
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|     ? $device->update({snmp_ver => $info->snmp_ver})
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|     : $device->set_column(snmp_ver => $info->snmp_ver);
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| 
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|   if ($comm->{community}) {
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|       $device->in_storage
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|         ? $device->update({snmp_comm => $comm->{community}})
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|         : $device->set_column(snmp_comm => $comm->{community});
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|   }
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| 
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|   # regardless of device in storage, save the hint
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|   $device->update_or_create_related('community',
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|     {snmp_auth_tag_read => $comm->{tag}}) if $comm->{tag};
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| 
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|   return $info;
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| }
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| 
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| sub _try_write {
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|   my ($info, $device, $comm) = @_;
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| 
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|   my $loc = $info->load_location;
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|   $info->set_location($loc) or return undef;
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|   return undef unless ($loc eq $info->load_location);
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| 
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|   $device->in_storage
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|     ? $device->update({snmp_ver => $info->snmp_ver})
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|     : $device->set_column(snmp_ver => $info->snmp_ver);
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| 
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|   # one of these two cols must be set
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|   $device->update_or_create_related('community', {
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|     ($comm->{tag} ? (snmp_auth_tag_write => $comm->{tag}) : ()),
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|     ($comm->{community} ? (snmp_comm_rw => $comm->{community}) : ()),
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|   });
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| 
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|   return $info;
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| }
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| 
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| sub _mk_info_commargs {
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|   my $comm = shift;
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|   return () unless ref {} eq ref $comm and scalar keys %$comm;
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| 
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|   return (Community => $comm->{community})
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|     if exists $comm->{community};
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| 
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|   my $seclevel =
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|     (exists $comm->{auth} ?
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|     (exists $comm->{priv} ? 'authPriv' : 'authNoPriv' )
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|                           : 'noAuthNoPriv');
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| 
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|   return (
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|     SecName  => $comm->{user},
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|     SecLevel => $seclevel,
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|     ( exists $comm->{auth} ? (
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|       AuthProto => uc ($comm->{auth}->{proto} || 'MD5'),
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|       AuthPass  => ($comm->{auth}->{pass} || ''),
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|       ( exists $comm->{priv} ? (
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|         PrivProto => uc ($comm->{priv}->{proto} || 'DES'),
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|         PrivPass  => ($comm->{priv}->{pass} || ''),
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|       ) : ()),
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|     ) : ()),
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|   );
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| }
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| 
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| sub _build_mibdirs {
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|   my $home = (setting('mibhome') || dir(($ENV{NETDISCO_HOME} || $ENV{HOME}), 'netdisco-mibs'));
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|   return map { dir($home, $_)->stringify }
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|              @{ setting('mibdirs') || _get_mibdirs_content($home) };
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| }
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| 
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| sub _get_mibdirs_content {
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|   my $home = shift;
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|   my @list = map {s|$home/||; $_} grep {m/[a-z0-9]/} grep {-d} glob("$home/*");
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|   return \@list;
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| }
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| 
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| true;
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