SNMP
Section: User Contributed Perl Documentation (3)
Updated: 2018-07-16
Page Index
NAME
SNMP - The Perl5 'SNMP' Extension Module for the Net-SNMP SNMP package.
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";
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 documentation,
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 synchronous and asynchronous operation through
a polymorphic API (i.e., method behaviour varies dependent on args
passed - see below).
SNMP::Session
$sess = new SNMP::Session(DestHost => 'host', ...)
The following arguments may be passed to new as a hash.
Basic Options
- DestHost
-
Hostname or IP address of the SNMP agent you want to talk to.
Specified in Net-SNMP formatted agent addresses. These addresses
typically look like one of the following:
localhost
tcp:localhost
tls:localhost
tls:localhost:9876
udp6:[::1]:9876
unix:/some/path/to/file/socket
Defaults to 'localhost'.
- Version
-
SNMP version to use.
The default is taken from library configuration - probably 3 [1, 2
(same as 2c), 2c, 3].
- Timeout
-
The number of micro-seconds to wait before resending a request.
The default is '1000000'
- Retries
-
The number of times to retry a request.
The default is '5'
- RetryNoSuch
-
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)
The default is '0'.
SNMPv3/TLS Options
- OurIdentity
-
Our X.509 identity to use, which should either be a fingerprint or the
filename that holds the certificate.
- TheirIdentity
-
The remote server's identity to connect to, specified as either a
fingerprint or a file name. Either this must be specified, or the
hostname below along with a trust anchor.
- TheirHostname
-
The remote server's hostname that is expected. If their certificate
was signed by a CA then their hostname presented in the certificate
must match this value or the connection fails to be established (to
avoid man-in-the-middle attacks).
- TrustCert
-
A trusted certificate to use as trust anchor (like a CA certificate)
for verifying a remote server's certificate. If a CA certificate is
used to validate a certificate then the TheirHostname parameter must
also be specified to ensure their presented hostname in the certificate
matches.
SNMPv3/USM Options
- SecName
-
The SNMPv3 security name to use (most for SNMPv3 with USM).
The default is 'initial'.
- SecLevel
-
The SNMPv3 security level to use [noAuthNoPriv, authNoPriv, authPriv] (v3)
The default is 'noAuthNoPriv'.
- SecEngineId
-
The SNMPv3 security engineID to use (if the snmpv3 security model
needs it; for example USM).
The default is <none>, security engineID and it will be probed if not
supplied (v3)
- ContextEngineId
-
The SNMPv3 context engineID to use.
The default is the <none> and will be set either to the SecEngineId
value if set or discovered or will be discovered in other ways if
using TLS (RFC5343 based discovery).
- Context
-
The SNMPv3 context name to use.
The default is '' (an empty string)
- AuthProto
-
The SNMPv3/USM authentication protocol to use [MD5, SHA].
The default is 'MD5'.
- AuthPass
-
The SNMPv3/USM authentication passphrase to use.
default <none>, authentication passphrase
- PrivProto
-
The SNMPv3/USM privacy protocol to use [DES, AES].
The default is 'DES'.
- PrivPass
-
The SNMPv3/USM privacy passphrase to use.
default <none>, privacy passphrase (v3)
- AuthMasterKey
-
- PrivMasterKey
-
- AuthLocalizedKey
-
- PrivLocalizedKey
-
Directly specified SNMPv3 USM user keys (used if you want to specify
the keys instead of deriving them from a password as above).
SNMPv1 and SNMPv2c Options
- Community
-
For SNMPv1 and SNMPv2c, the clear-text community name to use.
The default is 'public'.
Other Configuration Options
- 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
- 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')
- 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)
- 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)
- 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
- 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.
- 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).
- 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.
- ErrorStr
-
read-only, holds the error message assoc. w/ last request
- ErrorNum
-
read-only, holds the snmp_err or staus of last request
- ErrorInd
-
read-only, holds the snmp_err_index when appropriate
Private variables:
- DestAddr
-
internal field used to hold the translated DestHost field
- SessPtr
-
internal field used to cache a created session structure
- RemotePort
-
Obsolete. Please use the DestHost specifier to indicate the hostname
and port combination instead of this paramet.
SNMP::Session methods
- $sess->update(<fields>)
-
Updates the SNMP::Session object with the values fields
passed in as a hash list (similar to new(<fields>))
(WARNING! not fully implemented)
- $sess->get(<vars> [,<callback>])
-
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 asynchronously
- $sess->fget(<vars> [,<callback>])
-
do SNMP GET like 'get' and format the values according
the handlers specified in $sess->{VarFormats} and
$sess->{TypeFormats}
- $sess->getnext(<vars> [,<callback>])
-
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 asynchronously
- $sess->fgetnext(<vars> [,<callback>])
-
do SNMP GETNEXT like getnext and format the values according
the handlers specified in $sess->{VarFormats} and
$sess->{TypeFormats}
- $sess->set(<vars> [,<callback>])
-
do SNMP SET, multiple <vars> formats accepted.
the value field in all <vars> formats must be in a canonical
format (i.e., well known format) to ensure unambiguous
translation to SNMP MIB data value (see discussion of
canonical value format <vars> description section),
returns snmp_errno. If <callback> supplied method
will operate asynchronously
- $sess->getbulk(<non-repeaters>, <max-repeaters>, <vars>)
-
do an SNMP GETBULK, from the list of Varbinds, the single
next lexico instance is fetched for the first n Varbinds
as defined by <non-repeaters>. For remaining Varbinds,
the m lexico instances are retrieved each of the remaining
Varbinds, where m is <max-repeaters>.
- $sess->bulkwalk(<non-repeaters>, <max-repeaters>, <vars> [,<callback>])
-
Do a ``bulkwalk'' of the list of Varbinds. This is done by
sending a GETBULK request (see getbulk() above) for the
Varbinds. For each requested variable, the response is
examined to see if the next lexico instance has left the
requested sub-tree. Any further instances returned for
this variable are ignored, and the walk for that sub-tree
is considered complete.
If any sub-trees were not completed when the end of the
responses is reached, another request is composed, consisting
of the remaining variables. This process is repeated until
all sub-trees have been completed, or too many packets have
been exchanged (to avoid loops).
The bulkwalk() method returns an array containing an array of
Varbinds, one for each requested variable, in the order of the
variable requests. Upon error, bulkwalk() returns undef and
sets $sess->ErrorStr and $sess->ErrorNum. If a callback is
supplied, bulkwalk() returns the SNMP request id, and returns
immediately. The callback will be called with the supplied
argument list and the returned variables list.
Note: Because the client must ``discover'' that the tree is
complete by comparing the returned variables with those that
were requested, there is a potential ``gotcha'' when using the
max-repeaters value. Consider the following code to print a
list of interfaces and byte counts:
$numInts = $sess->get('ifNumber.0');
($desc, $in, $out) = $sess->bulkwalk(0, $numInts,
[['ifDescr'], ['ifInOctets'], ['ifOutOctets']]);
for $i (0..($numInts - 1)) {
printf "Interface %4s: %s inOctets, %s outOctets\n",
$$desc[$i]->val, $$in[$i]->val, $$out[$i]->val;
}
This code will produce *two* requests to the agent --- the first
to get the interface values, and the second to discover that all
the information was in the first packet. To get around this,
use '$numInts + 1' for the max_repeaters value. This asks the
agent to include one additional (unrelated) variable that signals
the end of the sub-tree, allowing bulkwalk() to determine that
the request is complete.
- $results = $sess->gettable(<TABLE OID>, <OPTIONS>)
-
This will retrieve an entire table of data and return a hash reference
to that data. The returned hash reference will have indexes of the
OID suffixes for the index data as the key. The value for each entry
will be another hash containing the data for a given row. The keys to
that hash will be the column names, and the values will be the data.
Example:
#!/usr/bin/perl
use SNMP;
use Data::Dumper;
my $s = new SNMP::Session(DestHost => 'localhost');
print Dumper($s->gettable('ifTable'));
On my machine produces:
$VAR1 = {
'6' => {
'ifMtu' => '1500',
'ifPhysAddress' => 'PV',
# ...
'ifInUnknownProtos' => '0'
},
'4' => {
'ifMtu' => '1480',
'ifPhysAddress' => '',
# ...
'ifInUnknownProtos' => '0'
},
# ...
};
By default, it will try to do as optimized retrieval as possible.
It'll request multiple columns at once, and use GETBULK if possible.
A few options may be specified by passing in an OPTIONS hash
containing various parameters:
-
- noindexes => 1
-
Instructs the code not to parse the indexes and place the results in
the second hash. If you don't need the index data, this will be
faster.
- columns => [ colname1, ... ]
-
This specifies which columns to collect. By default, it will try to
collect all the columns defined in the MIB table.
- repeat => COUNT
-
Specifies a GETBULK repeat COUNT. IE, it will request this many
varbinds back per column when using the GETBULK operation. Shortening
this will mean smaller packets which may help going through some
systems. By default, this value is calculated and attempts to guess
at what will fit all the results into 1000 bytes. This calculation is
fairly safe, hopefully, but you can either raise or lower the number
using this option if desired. In lossy networks, you want to make
sure that the packets don't get fragmented and lowering this value is
one way to help that.
- nogetbulk => 1
-
Force the use of GETNEXT rather than GETBULK. (always true for
SNMPv1, as it doesn't have GETBULK anyway). Some agents are great
implementers of GETBULK and this allows you to force the use of
GETNEXT operations instead.
- callback => \&subroutine
-
- callback => [\&subroutine, optarg1, optarg2, ...]
-
If a callback is specified, gettable will return quickly without
returning results. When the results are finally retrieved the
callback subroutine will be called (see the other sections defining
callback behaviour and how to make use of SNMP::MainLoop which is
required for this to work). An additional argument of the normal hash
result will be added to the callback subroutine arguments.
Note 1: internally, the gettable function uses it's own callbacks
which are passed to getnext/getbulk as appropriate.
Note 2: callback support is only available in the SNMP module version
5.04 and above. To test for this in code intending to support both
versions prior to 5.04 and 5.04 and up, the following should work:
if ($response = $sess->gettable('ifTable', callback => \&my_sub)) {
# got a response, gettable doesn't support callback
my_sub($response);
$no_mainloop = 1;
}
Deciding on whether to use SNMP::MainLoop is left as an exercise to
the reader since it depends on whether your code uses other callbacks
as well.
-
SNMP::TrapSession
$sess = new SNMP::Session(DestHost => 'host', ...)
supports all applicable fields from SNMP::Session
(see above)
SNMP::TrapSession methods
- $sess->trap(enterprise, agent, generic, specific, uptime, <vars>)
-
$sess->trap(enterprise=>'.1.3.6.1.4.1.2021', # or 'ucdavis' [default]
agent => '127.0.0.1', # or 'localhost',[dflt 1st intf on host]
generic => specific, # can be omitted if 'specific' supplied
specific => 5, # can be omitted if 'generic' supplied
uptime => 1234, # dflt to localhost uptime (0 on win32)
[[ifIndex, 1, 1],[sysLocation, 0, "here"]]); # optional vars
# always last
- trap(oid, uptime, <vars>) - v2 format
-
$sess->trap(oid => 'snmpRisingAlarm',
uptime => 1234,
[[ifIndex, 1, 1],[sysLocation, 0, "here"]]); # optional vars
# always last
Acceptable variable formats:
<vars> may be one of the following forms:
- SNMP::VarList
-
represents an array of MIB objects to get or set,
implemented as a blessed reference to an array of
SNMP::Varbinds, (e.g., [<varbind1>, <varbind2>, ...])
- SNMP::Varbind
-
represents a single MIB object to get or set, implemented as
a blessed reference to a 4 element array;
[<obj>, <iid>, <val>, <type>].
-
- <obj>
-
one of the following forms:
-
- 1)
-
leaf identifier (e.g., 'sysDescr') assumed to be
unique for practical purposes
- 2)
-
fully qualified identifier (e.g.,
'.iso.org.dod.internet.mgmt.mib-2.system.sysDescr')
- 3)
-
fully qualified, dotted-decimal, numeric OID (e.g.,
'.1.3.6.1.2.1.1.1')
-
- <iid>
-
the dotted-decimal, instance identifier. for
scalar MIB objects use '0'
- <val>
-
the SNMP data value retrieved from or being set
to the agents MIB. for (f)get(next) operations
<val> may have a variety of formats as determined by
session and package settings. However for set
operations the <val> format must be canonical to
ensure unambiguous translation. The canonical forms
are as follows:
-
- OBJECTID
-
dotted-decimal (e.g., .1.3.6.1.2.1.1.1)
- OCTETSTR
-
perl scalar containing octets
- INTEGER
-
decimal signed integer (or enum)
- NETADDR
-
dotted-decimal
- IPADDR
-
dotted-decimal
- COUNTER
-
decimal unsigned integer
- COUNTER64
-
decimal unsigned integer
- GAUGE
-
decimal unsigned integer
- UINTEGER
-
decimal unsigned integer
- TICKS
-
decimal unsigned integer
- OPAQUE
-
perl scalar containing octets
- NULL
-
perl scalar containing nothing
-
- <type>
-
SNMP data type (see list above), this field is
populated by 'get' and 'getnext' operations. In
some cases the programmer needs to populate this
field when passing to a 'set' operation. this
field need not be supplied when the attribute
indicated by <tag> is already described by loaded
Mib modules. for 'set's, if a numeric OID is used
and the object is not currently in the loaded Mib,
the <type> field must be supplied
-
- simple string
-
light weight form of <var> used to 'set' or 'get' a
single attribute without constructing an SNMP::Varbind.
stored in a perl scalar, has the form '<tag>.<iid>',
(e.g., 'sysDescr.0'). for 'set' operations the value
is passed as a second arg. Note: This argument form is
not updated in get[next] operations as are the other forms.
Acceptable callback formats
<callback> may be one of the following forms:
- without arguments
-
-
- \&subname
-
- sub { ... }
-
-
- or with arguments
-
-
- [ \&subname, $arg1, ... ]
-
- [ sub { ... }, $arg1, ... ]
-
- [ "method", $obj, $arg1, ... ]
-
-
callback will be called when response is received or timeout
occurs. the last argument passed to callback will be a
SNMP::VarList reference. In case of timeout the last argument
will be undef.
- &SNMP::MainLoop([<timeout>, [<callback>]])
-
to be used with async SNMP::Session
calls. MainLoop must be called after initial async calls
so return packets from the agent will be processed.
If no args supplied this function enters an infinite loop
so program must be exited in a callback or externally
interrupted. If <timeout(sic)
- &SNMP::finish()
-
This function, when called from an SNMP::MainLoop() callback
function, will cause the current SNMP::MainLoop() to return
after the callback is completed. finish() can be used to
terminate an otherwise-infinite MainLoop. A new MainLoop()
instance can then be started to handle further requests.
SNMP package variables and functions
- $SNMP::VERSION
-
the current version specifier (e.g., 3.1.0)
- $SNMP::auto_init_mib
-
default '1', set to 0 to disable automatic reading
of the MIB upon session creation. set to non-zero
to call initMib at session creation which will result
in MIB loading according to Net-SNMP env. variables (see
man mib_api)
- $SNMP::verbose
-
default '0', controls warning/info output of
SNMP module, 0 => no output, 1 => enables warning/info
output from SNMP module itself (is also controlled
by SNMP::debugging - see below)
- $SNMP::use_long_names
-
default '0', set to non-zero to enable the use of
longer Mib identifiers. see translateObj. will also
influence the formatting of <tag> in varbinds returned
from 'getnext' operations. Can be set on a per session
basis (UseLongNames)
- $SNMP::use_sprint_value
-
default '0', set to non-zero to enable formatting of
response values using the snmp libraries snprint_value
function. can also be set on a per session basis (see
UseSprintValue) Note: returned values may not be
suitable for 'set' operations
- $SNMP::use_enums
-
default '0',set non-zero to return values as enums and
allow sets using enums where appropriate. integer data
will still be accepted for set operations. can also be
set on a per session basis (see UseEnums)
- $SNMP::use_numeric
-
default to '0',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 entire OID will be
returned. Set on a per-session basis (see UseNumeric).
- $SNMP::best_guess
-
default '0'. 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). Can also be set
on a per session basis (see BestGuess)
- $SNMP::save_descriptions
-
default '0',set non-zero to have mib parser save
attribute descriptions. must be set prior to mib
initialization
- $SNMP::debugging
-
default '0', controls debugging output level
within SNMP module and libsnmp
-
- 1.
-
enables 'SNMP::verbose' (see above)
- 2.
-
level 1 plus snmp_set_do_debugging(1)
- 3.
-
level 2 plus snmp_set_dump_packet(1)
-
- $SNMP::dump_packet
-
default '0', set [non-]zero to independently set
snmp_set_dump_packet()
- SNMP::register_debug_tokens()
-
Allows to register one or more debug tokens, just like the -D option of snmpd.
Each debug token enables a group of debug statements. An example:
SNMP::register_debug_tokens(``tdomain,netsnmp_unix'');
%SNMP::MIB
a tied hash to access parsed
MIB information. After
the
MIB has been loaded this hash allows access to
to the parsed in
MIB meta-data(the structure of the
MIB (i.e., schema)). The hash returns blessed
references to
SNMP::MIB::NODE objects which represent
a single
MIB attribute. The nodes can be fetched with
multiple 'key' formats - the leaf name (e.g.,sysDescr)
or fully/partially qualified name (e.g.,
system.sysDescr) or fully qualified numeric
OID. The
returned node object supports the following fields:
- objectID
-
dotted decimal fully qualified OID
- label
-
leaf textual identifier (e.g., 'sysDescr')
- subID
-
leaf numeric OID component of objectID (e.g., '1')
- moduleID
-
textual identifier for module (e.g., 'RFC1213-MIB')
- parent
-
parent node
- children
-
array reference of children nodes
- nextNode
-
next lexico node (BUG!does not return in lexico order)
- type
-
returns application type (see getType for values)
- access
-
returns ACCESS (ReadOnly, ReadWrite, WriteOnly,
NoAccess, Notify, Create)
- status
-
returns STATUS (Mandatory, Optional, Obsolete,
Deprecated)
- syntax
-
returns 'textualConvention' if defined else 'type'
- textualConvention
-
returns TEXTUAL-CONVENTION
- TCDescription
-
returns the TEXTUAL-CONVENTION's DESCRIPTION field.
- units
-
returns UNITS
- hint
-
returns HINT
- enums
-
returns hash ref {tag => num, ...}
- ranges
-
returns array ref of hash ref [{low => num, high => num}, ...]
- description
-
returns DESCRIPTION ($SNMP::save_descriptions must
be set prior to MIB initialization/parsing)
- reference
-
returns the REFERENCE clause
- indexes
-
returns the objects in the INDEX clause
- implied
-
returns true if the last object in the INDEX is IMPLIED
MIB Functions
- &SNMP::setMib(<file>)
-
allows dynamic parsing of the mib and explicit
specification of mib file independent of environment
variables. called with no args acts like initMib,
loading MIBs indicated by environment variables (see
Net-SNMP mib_api docs). passing non-zero second arg
forces previous mib to be freed and replaced
(Note: second arg not working since freeing previous
Mib is more involved than before).
- &SNMP::initMib()
-
calls library init_mib function if Mib not already
loaded - does nothing if Mib already loaded. will
parse directories and load modules according to
environment variables described in Net-SNMP documentations.
(see man mib_api, MIBDIRS, MIBS, MIBFILE(S), etc.)
- &SNMP::addMibDirs(<dir>,...)
-
calls library add_mibdir for each directory
supplied. will cause directory(s) to be added to
internal list and made available for searching in
subsequent loadModules calls
- &SNMP::addMibFiles(<file>,...)
-
calls library read_mib function. The file(s)
supplied will be read and all Mib module definitions
contained therein will be added to internal mib tree
structure
- &SNMP::loadModules(<mod>,...)
-
calls library read_module function. The
module(s) supplied will be searched for in the
current mibdirs and and added to internal mib tree
structure. Passing special <mod>, 'ALL', will cause
all known modules to be loaded.
- &SNMP::unloadModules(<mod>,...)
-
*Not Implemented*
- &SNMP::translateObj(<var>[,arg,[arg]])
-
will convert a text obj tag to an OID and vice-versa.
Any iid suffix is retained numerically. Default
behaviour when converting a numeric OID to text
form is to return leaf identifier only
(e.g.,'sysDescr') but when $SNMP::use_long_names
is non-zero or a non-zero second arg is supplied it
will return a longer textual identifier. An optional
third argument of non-zero will cause the module name
to be prepended to the text name (e.g.
'SNMPv2-MIB::sysDescr'). When converting a text obj,
the $SNMP::best_guess option is used. If no Mib is
loaded when called and $SNMP::auto_init_mib is enabled
then the Mib will be loaded. Will return 'undef' upon
failure.
- &SNMP::getType(<var>)
-
return SNMP data type for given textual identifier
OBJECTID, OCTETSTR, INTEGER, NETADDR, IPADDR, COUNTER
GAUGE, TIMETICKS, OPAQUE, or undef
- &SNMP::mapEnum(<var>)
-
converts integer value to enumertion tag defined
in Mib or converts tag to integer depending on
input. the function will return the corresponding
integer value *or* tag for a given MIB attribute
and value. The function will sense which direction
to perform the conversion. Various arg formats are
supported
-
- $val = SNMP::mapEnum($varbind);
-
where $varbind is SNMP::Varbind or equiv.
note: $varbind will be updated
- $val = SNMP::mapEnum('ipForwarding', 'forwarding');
-
- $val = SNMP::mapEnum('ipForwarding', 1);
-
-
Exported SNMP utility functions
Note: utility functions do not support async operation yet.
- &snmp_get()
-
takes args of SNMP::Session::new followed by those of
SNMP::Session::get
- &snmp_getnext()
-
takes args of SNMP::Session::new followed by those of
SNMP::Session::getnext
- &snmp_set()
-
takes args of SNMP::Session::new followed by those of
SNMP::Session::set
- &snmp_trap()
-
takes args of SNMP::TrapSession::new followed by those of
SNMP::TrapSession::trap
Trouble Shooting
If problems occur there are number areas to look at to narrow down the
possibilities.
The first step should be to test the Net-SNMP installation
independently from the Perl5 SNMP interface.
Try running the apps from the Net-SNMP distribution.
Make sure your agent (snmpd) is running and properly configured with
read-write access for the community you are using.
Ensure that your MIBs are installed and enviroment variables are set
appropriately (see man mib_api)
Be sure to remove old net-snmp installations and ensure headers and
libraries from old CMU installations are not being used by mistake.
If the problem occurs during compilation/linking check that the snmp
library being linked is actually the Net-SNMP library (there have been
name conflicts with existing snmp libs).
Also check that the header files are correct and up to date.
Sometimes compiling the Net-SNMP library with
'position-independent-code' enabled is required (HPUX specifically).
If you cannot resolve the problem you can post to
comp.lang.perl.modules or
net-snmp-users@net-snmp-users@lists.sourceforge.net
please give sufficient information to analyze the problem (OS type,
versions for OS/Perl/Net-SNMP/compiler, complete error output, etc.)
Acknowledgements
Many thanks to all those who supplied patches, suggestions and
feedback.
Joe Marzot (the original author)
Wes Hardaker and the net-snmp-coders
Dave Perkins
Marcel Wiget
David Blackburn
John Stofell
Gary Hayward
Claire Harrison
Achim Bohnet
Doug Kingston
Jacques Vidrine
Carl Jacobsen
Wayne Marquette
Scott Schumate
Michael Slifcak
Srivathsan Srinivasagopalan
Bill Fenner
Jef Peeraer
Daniel Hagerty
Karl "Rat" Schilke and Electric Lightwave, Inc.
Perl5 Porters
Alex Burger
Apologies to any/all who's patch/feature/request was not mentioned or
included - most likely it was lost when paying work intruded on my
fun. Please try again if you do not see a desired feature. This may
actually turn out to be a decent package with such excellent help and
the fact that I have more time to work on it than in the past.
AUTHOR
bugs, comments, questions to
net-snmp-users@lists.sourceforge.net
Copyright
Copyright (c) 1995-2000 G. S. Marzot. All rights reserved.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
Copyright (c) 2001-2002 Networks Associates Technology, Inc. All
Rights Reserved. This program is free software; you can
redistribute it and/or modify it under the same terms as Perl
itself.