snmp.pm

开发snmp的开发包有两个开放的SNMP开发库

sub STORE {
    SNMP::_debug_internals($_[1]);
    ${$_[0]} = $_[1];
}

sub DELETE {
    SNMP::_debug_internals(0);
    ${$_[0]} = undef;
}

package SNMP::DUMP_PACKET;
# controls packet dump output from libsnmp

sub TIESCALAR { my $class = shift; my $val; bless \$val, $class; }

sub FETCH { ${$_[0]}; }

sub STORE { SNMP::_dump_packet($_[1]); ${$_[0]} = $_[1]; }

sub DELETE { SNMP::_dump_packet(0); ${$_[0]} = 0; }

package SNMP::MIB;

sub TIEHASH {
    bless {};
}

sub FETCH {
    my $this = shift;
    my $key = shift;

    if (!defined $this->{$key}) {
	tie(%{$this->{$key}}, SNMP::MIB::NODE, $key) or return undef;
    }
    $this->{$key};
}

sub STORE {
    warn "STORE(@_) : write access to the MIB not implemented\n";
}

sub DELETE {
    delete $_[0]->{$_[1]}; # just delete cache entry
}

sub FIRSTKEY { return '.1'; } # this should actually start at .0 but
                              # because nodes are not stored in lexico
                              # order in ucd-snmp node tree walk will
                              # miss most of the tree
sub NEXTKEY { # this could be sped up by using an XS __get_next_oid maybe
   my $node = $_[0]->FETCH($_[1])->{nextNode};
   $node->{objectID};
}
sub EXISTS { exists $_[0]->{$_[1]} || $_[0]->FETCH($_[1]); }
sub CLEAR { undef %{$_[0]}; } # clear the cache

package SNMP::MIB::NODE;
my %node_elements =
    (
     objectID => 0, # dotted decimal fully qualified OID
     label => 0,    # leaf textual identifier (e.g., 'sysDescr')
     subID => 0,    # leaf numeric OID component of objectID (e.g., '1')
     moduleID => 0, # textual identifier for module (e.g., 'RFC1213-MIB')
     parent => 0,   # parent node
     children => 0, # array reference of children nodes
     indexes => 0,  # returns array of column labels
     varbinds => 0, # returns array of trap/notification varbinds
     nextNode => 0, # next lexico node (BUG! does not return in lexico order)
     type => 0,     # returns simple type (see getType for values)
     access => 0,   # returns ACCESS (ReadOnly, ReadWrite, WriteOnly,
                    # NoAccess, Notify, Create)
     status => 0,   # returns STATUS (Mandatory, Optional, Obsolete,
                    # Deprecated)
     syntax => 0,   # returns 'textualConvention' if defined else 'type'
     textualConvention => 0, # returns TEXTUAL-CONVENTION
     units => 0,    # returns UNITS
     hint => 0,     # returns HINT
     enums => 0,    # returns hash ref {tag => num, ...}
     ranges => 0,   # returns array ref of hash ref [{low => num, high => num}]
     defaultValue => 0, # returns default value
     description => 0, # returns DESCRIPTION ($SNMP::save_descriptions must
                    # be set prior to MIB initialization/parsing
     augments => 0, # textual identifier of augmented object
    );

# sub TIEHASH - implemented in SNMP.xs

# sub FETCH - implemented in SNMP.xs

sub STORE {
    warn "STORE(@_): write access to MIB node not implemented\n";
}

sub DELETE {
    warn "DELETE(@_): write access to MIB node not implemented\n";
}

sub FIRSTKEY { my $k = keys %node_elements; (each(%node_elements))[0]; }
sub NEXTKEY { (each(%node_elements))[0]; }
sub EXISTS { exists($node_elements{$_[1]}); }
sub CLEAR {
    warn "CLEAR(@_): write access to MIB node not implemented\n";
}

#sub DESTROY {
#    warn "DESTROY(@_): write access to MIB node not implemented\n";
#    # print "SNMP::MIB::NODE::DESTROY : $_[0]->{label} ($_[0])\n";
#}
package SNMP::MIB::SAVE_DESCR;

sub TIESCALAR { my $class = shift; my $val; bless \$val, $class; }

sub FETCH { ${$_[0]}; }

sub STORE { SNMP::_set_save_descriptions($_[1]); ${$_[0]} = $_[1]; }

sub DELETE { SNMP::_set_save_descriptions(0); ${$_[0]} = 0; }

package SNMP::MIB::REPLACE_NEWER;               # Controls MIB parsing

sub TIESCALAR { my $class = shift; my $val; bless \$val, $class; }

sub FETCH { ${$_[0]}; }

sub STORE {
    SNMP::_set_replace_newer($_[1]);
    ${$_[0]} = $_[1];
}

sub DELETE {
    SNMP::_set_replace_newer(0);
    ${$_[0]} = 0;
}

package SNMP::MIB::MIB_OPTIONS;

sub TIESCALAR { my $class = shift; my $val; bless \$val, $class; }

sub FETCH { ${$_[0]}; }

sub STORE { SNMP::_mib_toggle_options($_[1]); ${$_[0]} = $_[1]; }

sub DELETE { SNMP::_mib_toggle_options(0); ${$_[0]} = ''; }

package SNMP;
END{SNMP::_sock_cleanup() if defined &SNMP::_sock_cleanup;}
# Autoload methods go after __END__, and are processed by the autosplit prog.

1;
__END__

=head1 NAME

SNMP - The Perl5 'SNMP' Extension Module for the Net-SNMP SNMP package.

=head1 SYNOPSIS

 use SNMP;
 ...
 $sess = new SNMP::Session(DestHost => localhost, Community => public);
 $val = $sess->get('sysDescr.0');
 ...
 $vars = new SNMP::VarList([sysDescr,0], [sysContact,0], [sysLocation,0]);
 @vals = $sess->get($vars);
 ...
 $vb = new SNMP::Varbind();
 do {
    $val = $sess->getnext($vb);
    print "@{$vb}\n";
 } until ($sess->{ErrorNum});
 ...
 $SNMP::save_descriptions = 1;
 SNMP::initMib(); # assuming mib is not already loaded
 print "$SNMP::MIB{sysDescr}{description}\n";

=head1 DESCRIPTION


Note: The perl SNMP 5.0 module which comes with net-snmp 5.0 and
higher is different than previous versions in a number of ways.  Most
importantly, it behaves like a proper net-snmp application and calls
init_snmp properly, which means it will read configuration files and
use those defaults where appropriate automatically parse MIB files,
etc.  This will likely affect your perl applications if you have, for
instance, default values set up in your snmp.conf file (as the perl
module will now make use of those defaults).  The docmuentation,
however, has sadly not been updated yet (aside from this note), nor is
the read_config default usage implementation fully complete.

The basic operations of the SNMP protocol are provided by this module
through an object oriented interface for modularity and ease of use.
The primary class is SNMP::Session which encapsulates the persistent
aspects of a connection between the management application and the
managed agent. Internally the class is implemented as a blessed hash
reference. This class supplies 'get', 'getnext', 'set', 'fget', and
'fgetnext' method calls. The methods take a variety of input argument
formats and support both syncronous and asyncronous operation through
a polymorphic API (i.e., method behaviour varies dependent on args
passed - see below).

=head1 SNMP::Session

$sess = new SNMP::Session(DestHost => 'host', ...)

The following arguments may be passed to new as a hash.

=over 4

=item DestHost

default 'localhost', hostname or ip addr of SNMP agent

=item Community

default 'public', SNMP community string (used for both R/W)

=item Version

default taken from library configuration - probably 3 [1, 2 (same as 2c), 2c, 3]

=item RemotePort

default '161', allow remote UDP port to be overriden

=item Timeout

default '1000000', micro-seconds before retry

=item Retries

default '5', retries before failure

=item RetryNoSuch

default '0', if enabled NOSUCH errors in 'get' pdus will
be repaired, removing the varbind in error, and resent -
undef will be returned for all NOSUCH varbinds, when set
to '0' this feature is disabled and the entire get request
will fail on any NOSUCH error (applies to v1 only)

=item SecName

default 'initial', security name (v3)

=item SecLevel

default 'noAuthNoPriv', security level [noAuthNoPriv,
authNoPriv, authPriv] (v3)

=item SecEngineId

default <none>, security engineID, will be probed if not
supplied (v3)

=item ContextEngineId

default <SecEngineId>, context engineID, will be
probed if not supplied (v3)

=item Context

default '', context name (v3)

=item AuthProto

default 'MD5', authentication protocol [MD5, SHA] (v3)

=item AuthPass

default <none>, authentication passphrase

=item PrivProto

default 'DES', privacy protocol [DES, AES] (v3)

=item PrivPass

default <none>, privacy passphrase (v3)

=item AuthMasterKey

=item PrivMasterKey

=item AuthLocalizedKey

=item PrivLocalizedKey

Directly specified SNMPv3 USM user keys (used if you want to specify
the keys instead of deriving them from a password as above).

=item VarFormats

default 'undef', used by 'fget[next]', holds an hash
reference of output value formatters, (e.g., {<obj> =>
<sub-ref>, ... }, <obj> must match the <obj> and format
used in the get operation. A special <obj>, '*', may be
used to apply all <obj>s, the supplied sub is called to
translate the value to a new format. The sub is called
passing the Varbind as the arg

=item TypeFormats

default 'undef', used by 'fget[next]', holds an hash
reference of output value formatters, (e.g., {<type> =>
<sub-ref>, ... }, the supplied sub is called to translate
the value to a new format, unless a VarFormat mathces first
(e.g., $sess->{TypeFormats}{INTEGER} = \&mapEnum();
although this can be done more efficiently by enabling
$SNMP::use_enums or session creation param 'UseEnums')

=item UseLongNames

defaults to the value of SNMP::use_long_names at time
of session creation. set to non-zero to have <tags>
for 'getnext' methods generated preferring longer Mib name
convention (e.g., system.sysDescr vs just sysDescr)

=item UseSprintValue

defaults to the value of SNMP::use_sprint_value at time
of session creation. set to non-zero to have return values
for 'get' and 'getnext' methods formatted with the libraries
snprint_value function. This will result in certain data types
being returned in non-canonical format Note: values returned
with this option set may not be appropriate for 'set' operations
(see discussion of value formats in <vars> description section)

=item UseEnums

defaults to the value of SNMP::use_enums at time of session
creation. set to non-zero to have integer return values
converted to enumeration identifiers if possible, these values
will also be acceptable when supplied to 'set' operations

=item UseNumeric

defaults to the value of SNMP::use_numeric at time of session
creation. set to non-zero to have <tags> for get methods returned
as numeric OID's rather than descriptions.  UseLongNames will be
set so that the full OID is returned to the caller.

=item BestGuess

defaults to the value of SNMP::best_guess at time of session
creation. this setting controls how <tags> are parsed.  setting to
0 causes a regular lookup.  setting to 1 causes a regular expression 
match (defined as -Ib in snmpcmd) and setting to 2 causes a random 
access lookup (defined as -IR in snmpcmd).

=item NonIncreasing

defaults to the value of SNMP::non_increasing at time of session
creation. this setting controls if a non-increasing OID during
bulkwalk will causes an error. setting to 0 causes the default
behaviour (which may, in very badly performing agents, result in a never-ending loop).
setting to 1 causes an error (OID not increasing) when this error occur.

=item ErrorStr

read-only, holds the error message assoc. w/ last request

=item ErrorNum

read-only, holds the snmp_err or staus of last request

=item ErrorInd

read-only, holds the snmp_err_index when appropriate

=back

Private variables:

=over

=item DestAddr

internal field used to hold the translated DestHost field

=item SessPtr

internal field used to cache a created session structure

=back

=head2 SNMP::Session methods

=over

=item $sess->update(E<lt>fieldsE<gt>)

Updates the SNMP::Session object with the values fields
passed in as a hash list (similar to new(E<lt>fieldsE<gt>))
B<(WARNING! not fully implemented)>

=item $sess->get(E<lt>varsE<gt> [,E<lt>callbackE<gt>])

do SNMP GET, multiple <vars> formats accepted.
for syncronous operation <vars> will be updated
with value(s) and type(s) and will also return
retrieved value(s). If <callback> supplied method
will operate asyncronously

=item $sess->fget(E<lt>varsE<gt> [,E<lt>callbackE<gt>])

do SNMP GET like 'get' and format the values according
the handlers specified in $sess->{VarFormats} and
$sess->{TypeFormats}

=item $sess->getnext(E<lt>varsE<gt> [,E<lt>callbackE<gt>])

do SNMP GETNEXT, multiple <vars> formats accepted,
returns retrieved value(s), <vars> passed as arguments are
updated to indicate next lexicographical <obj>,<iid>,<val>,
and <type>

Note: simple string <vars>,(e.g., 'sysDescr.0')
form is not updated. If <callback> supplied method
will operate asyncronously

=item $sess->fgetnext(E<lt>varsE<gt> [,E<lt>callbackE<gt>])