The Perl5 'SNMP' Extension Module
for the Net-SNMP Library
Contents:
Introduction:
Availability:
Contact:
Supported Platforms:
Release Notes:
Installation:
Operational Description:
Trouble Shooting:
Acknowledgments:
History:
Copyright:
Introduction:
******************************NOTE NOTE NOTE**************************
This module now relies on many other modules. Ideally, do not try
to build it independently, as it won't work as well. Instead of
running "perl Makefile.PL" in this directory, run it in the
net-snmp/perl directory instead which has a global makefile used to
build all the sub-modules in their proper order.
******************************NOTE NOTE NOTE**************************
Note: The perl SNMP 5.x 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).
This is the Perl5 'SNMP' extension module. The SNMP module provides a
full featured, tri-lingual SNMP (SNMPv3, SNMPv2c, SNMPv1) API. The
SNMP module also provides an interface to the SMI MIB parse-tree for
run-time access to parsed MIB data. The SNMP module internals rely on
the Net-SNMP toolkit library (previously known as ucd-snmp). For
information on the Net-SNMP library see the documentation provided
with the Net-SNMP distribution or the project web page available on
'Source Forge':
http://www.net-snmp.org/
Availability:
The most recent release of the Perl5 SNMP module can be found bundled
with the latest Net-SNMP distibution available from:
http://www.net-snmp.org/download.html
(Note: The perl SNMP distribution obtained this way has the highest
chance of being up to date and compatible with the Net-SNMP version
with which it is bundled.)
A seperately bundled package of the SNMP module can be obtained from CPAN.
(Note: In previous releases this module was compatible with the CMU
SNMP library. Starting with Perl5/SNMP-1.7 this module will *only*
work with the Net-SNMP (aka ucd-snmp) library due to dependence on new
features)
Contact:
The following mailing list should be consider the primary support
mechanism for this module:
net-snmp-users ATATAT lists.sourceforge.net mail list
(see http://www.net-snmp.org/lists/users/ to subscribe)
Supported Platforms:
Linux 1.2.x, 2.x
Solaris 2.x (see the net-snmp README.solaris file!)
MS Windows
Many other UNIX variants
Let us know what it *doesn't* work on, as it should on most systems
Release Notes:
SNMP module version 5.x is being developed against NET-SNMP-5.0
see http://www.net-snmp.org/ for details.
Compatibility with earlier or later versions of Net-SNMP or
UCD-SNMP is not guaranteed due to the dynamic nature of open
software development :). The perl module will check the version of
net-snmp you have installed for a match and warn you if they don't
match exactly.
KNOWN BUGS:
The make test suite likely won't work perfectly. It relies on
running an existing Net-SNMP SNMP agent and various configuration
which makes it very hard to ensure exact compatibility. If "make
test" fails on you we suggest you install the module anyway.
(none?) (HA!)
**********************************************************************
* the rest of this file is likely out of date ************************
* the rest of this file is likely out of date ************************
* the rest of this file is likely out of date ************************
**********************************************************************
Installation:
Build and install the Net-SNMP package - see Net-SNMP README and
INSTALL docs.
(Note: To ensure that any previous Net-SNMP, ucd-snmp or cmu snmp
installation's library or headers are not used by mistake, use the
-NET-SNMP-CONFIG directive to explicitly set the path to the
net-snmp-config command that knows about the net-snmp installation you
want to use.)
NOTE: build all the perl modules at once using the Makefile.PL in the
net-snmp/perl directory rather than the one in this directory.
Unix:
cd net-snmp/perl
perl Makefile.PL [-NET-SNMP-CONFIG="sh ../../net-snmp-config"] [-NET-SNMP-IN-SOURCE=true]
make
make test
make install
FreeBSD:
cd net-snmp/perl
perl Makefile.PL -NET-SNMP-CONFIG="sh ../../net-snmp-config" -NET-SNMP-IN-SOURCE=true
make
make test
make install
Win32 (MSVC++)
This section covers installation of the Perl modules for Microsoft Visual
C++ 6.0 and Microsoft Microsoft Development Environment 2003/2003
(MSVC 7.0/7.1). See the following sections for Cygwin and MinGW.
ActiveState Perl is required.
Note: With ActiveState Perl (currently at 5.8.2 build 808) and possibly other
versions of Perl on Windows, if a Perl script modifies a
system environment variable and then calls a C function, the
C function will not see the new environment variable. This
problem can be seen with the failure of test #3 in the SNMP
conf test (perl/SNMP/t/conf.t). The change to the
SNMPCONFPATH env variable is not seen by the calls to the C
SNMP module.
Note: The source code should *not* be in a folder that contains a space. For
example, compiling in your 'My Documents' or your Desktop (usually
c:\Documents and Settings\xxxx\Desktop) is not supported.
Automatic building / testing with nmakeperl.bat:
1. Ensure a static version of Net-SNMP has been compiled and
installed. Also ensure the DLL version of snmplib has been
compiled and installed. The Perl modules will not function
correctly without a shared snmplib library or DLL.
2. Install the regex win32 package (gnu_regex.exe). It is available from
http://people.delphiforums.com/gjc/gnu_regex.html
a. Copy regex.h to the include folder of MSVC++
Example: "C:\Program Files\Microsoft Visual Studio .NET 2003\
Vc7\include\regex.h"
b. Copy gnu_regex.lib to the lib folder of MSVC++
Example: "C:\Program Files\Microsoft Visual Studio .NET 2003\
Vc7\lib\gnu_regex.lib"
c. Copy gnu_regex.dll to your %windir%\system32 folder
Example: "C:\winnt\system32\gnu_regex.dll"
3. Set the environment PATH to locate "nmake", "cl", and "link".
Visual Studio installs a VCVARS32.BAT batch file for this purpose.
4. Using a command prompt window, cd to the source base directory.
5. Invoke win32\nmakeperl.bat to build the Perl SNMP modules. If you see
errors, review the "nmake.out" file first. If no errors there,
then the modules built correctly, but the tests did not rigourously
prove the mettle of the modules. Review "nmaketest.out". If the
first three sections mostly pass, the modules are well formed.
NOTE: If the tests fail, there may be a perl application left hanging.
Use the Task Manager to remove any stale perl or snmp*.exe process.
6. The final step is to invoke "nmake install". If no errors occurred,
then the SNMP modules are available for use by your Perl programs.
Manual building / testing:
1. Ensure a static version of Net-SNMP has been compiled and
installed. Also ensure the DLL version of snmplib has been
compiled and installed. The Perl modules will not function
correctly without a shared snmplib library or DLL.
2. Install the regex win32 package (gnu_regex.exe). It is available from
http://people.delphiforums.com/gjc/gnu_regex.html
a. Copy regex.h to the include folder of MSVC++
Example: "C:\Program Files\Microsoft Visual Studio .NET 2003\
Vc7\include\regex.h"
b. Copy gnu_regex.lib to the lib folder of MSVC++
Example: "C:\Program Files\Microsoft Visual Studio .NET 2003\
Vc7\lib\gnu_regex.lib"
c. Copy gnu_regex.dll to your %windir%\system32 folder
Example: "C:\winnt\system32\gnu_regex.dll"
3. Set the environment PATH to locate "nmake", "cl", and "link".
Visual Studio installs a VCVARS32.BAT for this purpose.
4. Using a command prompt window, cd to the perl directory.
5. Type:
perl Makefile.PL CAPI=TRUE -NET-SNMP-IN-SOURCE=TRUE
to compile against the RELEASE version of Net-SNMP, or:
perl Makefile.PL CAPI=TRUE -NET-SNMP-IN-SOURCE=TRUE -NET-SNMP-DEBUG=TRUE
to compile against the DEBUG version of Net-SNMP.
nmake
nmake test
nmake install
Note: The --NET-SNMP-IN-SOURCE=TRUE causes the Makefile to use the
library files from the installed Net-SNMP directory.
To specify the installed Net-SNMP directory, use:
perl Makefile.PL CAPI=TRUE -NET-SNMP-PATH="c:\usr"
Note: -NET-SNMP-DEBUG has no effect while compiling against an
installed copy of Net-SNMP.
Note: To include OpenSSL, see the net-snmp/README.win32 to compile
libsnmp with libeay32 and see that libeay.lib is in the
lib folder, or in the lib folder of the installed
Net-SNMP if using -NET-SNMP-PATH. For example,
c:\usr\lib
Note: 'nmake test' will automatically start and stop the
agent(snmpd) and trap receiver (snmptrapd) while testing the
SNMP module.
Win32 (Cygwin):
cd net-snmp\perl
perl Makefile.PL -NET-SNMP-IN-SOURCE=true
make
make test
make install
If you get an error saying your system can't compile, you are
probably missing the regex library. Install regex from
http://mirrors.sunsite.dk/cygwin/release/regex/regex-4.4-2-src.tar.bz2
Note: The source code should *not* be in a folder that contains a space. For
example, compiling in your 'My Documents' or your Desktop (usually
c:\Documents and Settings\xxxx\Desktop) is not supported.
Win32 (MinGW):
Note: As of February 25th, 2004, the MinGW build of Net-SNMP does not
compile the DLL version of libsnmp. Some modules will not function
correctly without a shared library / DLL. The OID module does not
appear to work at all without the DLL, and some parts of other
modules may not work. For example, sharing configurations between
modules which is why the SNMP conf test fails.
Note: The source code should *not* be in a folder that contains a space. For
example, compiling in your 'My Documents' or your Desktop (usually
c:\Documents and Settings\xxxx\Desktop) is not supported.
These directions are for MinGW 3.1.0 with MSYS 1.0.9 and ActiveState Perl.
Compiling the Perl modules using a MinGW built Perl environment has not
been tested.
Note: With ActiveState Perl (currently at 5.8.2 build 808) and
possibly other versions of Perl on Windows, if a Perl script
modifies a system environment variable and then calls a C
function, the C function will not see the new environment
variable. This problem can be seen with the failure of test
#3 in the SNMP conf test (perl/SNMP/t/conf.t). The change to
the SNMPCONFPATH env variable is not seen by the calls to the
C SNMP module.
The main Net-SNMP package must be compiled with the regex library.
See Net-SNMP README.win32 for compiling with MinGW.
The following additional software is required:
dmake:
http://www.cpan.org/authors/id/GSAR/dmake-4.1pl1-win32.zip
ExtUtils-FakeConfig:
http://search.cpan.org/~mbarbon/ExtUtils-FakeConfig-0.05/
Note: A PPM package is available from ActiveState for
ExtUtils-FakeConfig, but it does not include the
make_implib.pl script. Downloading from CPAN is
recommended.
Installing DMAKE and ExtUtils-FakeConfig:
-----------------------------------------
1. Install DMAKE as described in the README.NOW contained in the DMAKE .ZIP
file ensuring the DMAKE program can be found in the system path.
2. Extract ExtUtils-FakeConfig-0.05.zip to a temporary folder.
3. Add the MinGW bin folder to your system path.
4. Open a Windows command prompt (cmd) and cd into
ExtUtils-FakeConfig-0.05 and typet he following to build and
install the ExtUtils-FakeConfig module:
perl Makefile.PL
dmake
dmake install
5. A Perl import library needs to be created using the ExtUtils-FakeConfig
make_implib.pl script.
For ActiveState Perl 5.6.x installed to c:\Perl, type the
following on one line:
perl script/make_implib.pl --output-dir=C:/Perl/lib/CORE
--output-lib=libperl56.a --target=mingw c:/Perl/bin/Perl56.dll
For ActiveState Perl 5.8.x installed to c:\Perl, type the
following on one line:
perl script/make_implib.pl --output-dir=C:/Perl/lib/CORE
--output-lib=libperl58.a --target=mingw c:/Perl/bin/Perl58.dll
Building the Perl module:
-------------------------
1. Complete the section titled 'Installing DMAKE and ExtUtils-FakeConfig'
2. Open an MSYS shell and cd into the net-snmp/Perl folder and type the
following on one line:
perl -MConfig_m Makefile.PL -NET-SNMP-IN-SOURCE=true DEFINE=-DMINGW_PERL
3. Open a Windows command prompt (cmd) and cd into the net-snmp/perl folder
and type:
dmake
dmake test
dmake install
Note: 'dmake test' will automatically start and stop the agent(snmpd) and
trap receiver (snmptrapd) while testing the SNMP module.
4. Remove the MinGW bin folder to your system path if it was not already in
your path for step 3 of 'Installing DMAKE and ExtUtils-FakeConfig'.
Operational Description:
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' and other 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).
A description of the fields which can be specified when an
SNMP::Session object is created follows:
SNMP::Session
public:
DestHost - default 'localhost', hostname or ip addr of SNMP agent
Community - default 'public', SNMP community string (used for both R/W)
Version - default '1', [2 (same as 2c), 2c, 3]
RemotePort - default '161', allow remote UDP port to be overridden
Timeout - default '1000000', micro-seconds before retry
Retries - default '5', retries before failure
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)
SecName - default 'initial', security name (v3)
SecLevel - default 'noAuthNoPriv', security level [noAuthNoPriv,
authNoPriv, authPriv] (v3)
SecEngineId - default <none>, security engineID, will be probed if not
supplied (v3)
ContextEngineId - default <SecEngineId>, context engineID, will be
probed if not supplied (v3)
Context - default '', context name (v3)
AuthProto - default 'MD5', authentication protocol [MD5, SHA] (v3)
AuthPass - default <none>, authentication passphrase
PrivProto - default 'DES', privacy protocol [DES] (v3)
PrivPass - default <none>, privacy passphrase (v3)
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., $session->{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
sprint_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> returned by the 'get'
methods untranslated (i.e. dotted-decimal). Setting the
UseLongNames value for the session is highly recommended.
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).
ErrorStr - read-only, holds the error message assoc. w/ last request
ErrorNum - read-only, holds the snmp_err or status of last request
ErrorInd - read-only, holds the snmp_err_index when appropriate
private:
DestAddr - internal field used to hold the translated DestHost field
SessPtr - internal field used to cache a created session structure
methods:
new(<fields>) - Constructs a new SNMP::Session object. The fields are
passed to the constructor as a hash list
(e.g., $session = new SNMP::Session(DestHost => 'foo',
Community => 'private');), returns an object reference
or undef in case of error.
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)
get(<vars>[,<callback>])
- do SNMP GET, multiple <vars> formats accepted.
for synchronous 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
fget(<vars>[,<callback>])
- do SNMP GET like 'get' and format the values according
the handlers specified in $sess->{VarFormats} and
$sess->{TypeFormats}. Async *not supported*
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
fgetnext(<vars>[,<callback>])
- do SNMP GETNEXT like getnext and format the values according
the handlers specified in $sess->{VarFormats} and
$sess->{TypeFormats}. Async *not supported*
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 true on success or undef on error. If <callback>
supplied method will operate asynchronously
getbulk(<non-repeaters>, <max-repeaters>, <vars> [, <callback>])
- 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>.
bulkwalk(<non-repeaters>, <max-repeaters>, <vars> [, <callback>])
- do an "SNMP bulkwalk" on the given variables. Bulkwalk is
implemented by sending an SNMP GETBULK request to fetch the
variables. Objects are copied to the return list until the
sub-tree is exited. If the request is not completed at the
end of a packet, a new request is created, starting where
the previous packet left off. This implementation is able
to handle multiple repeated vars, as well as non-repeaters.
Returns a list (or, in scalar context, a reference to a
list) of arrays of VarBinds. The VarBinds consist of the
responses for each requested variable. bulkwalk() leaves
the original Varbinds list intact to facilitate querying
of multiple devices.
SNMP::TrapSession - supports all applicable fields from SNMP::Session
(see above)
methods:
new(<fields>) - Constructs a new SNMP::TrapSession object. The fields are
passed to the constructor as a hash list
(e.g., $trapsess = new SNMP::Session(DestHost => 'foo',
Community => 'private');), returns an object reference
or undef in case of error.
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
or v2 format
trap(oid, uptime, <vars>)
$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 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 sprint_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 '0', set to non-zero to return tags as numeric
OID's, instead of translating them. Also setting
$SNMP::use_long_names to non-zero is highly recommended.
$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)
$SNMP::dump_packet - default '0', set [non-]zero to independently set
snmp_set_dump_packet()
%SNMP::MIB - a tied hash to access parsed MIB information. After
the MIB has been loaded this hash allows access to
to the parsed in MIB meta-data(the structure of the
MIB (i.e., schema)). The hash returns blessed
references to SNMP::MIB::NODE objects which represent
a single MIB attribute. The nodes can be fetched with
multiple 'key' formats - the leaf name (e.g.,sysDescr)
or fully/partially qualified name (e.g.,
system.sysDescr) or fully qualified numeric OID. The
returned node object supports the following fields:
objectID - dotted decimal fully qualified OID
label - leaf textual identifier (e.g., 'sysDescr')
subID - leaf numeric OID component of objectID (e.g., '1')
moduleID - textual identifier for module (e.g., 'RFC1213-MIB')
parent - parent node
children - array reference of children nodes
nextNode - next lexico node (BUG!does not return in lexico order)
type - returns application type (see getType for values)
access - returns ACCESS (ReadOnly, ReadWrite, WriteOnly,
NoAccess, Notify, Create)
status - returns STATUS (Mandatory, Optional, Obsolete,
Deprecated, Current)
syntax - returns 'textualConvention' if defined else 'type'
textualConvention - returns TEXTUAL-CONVENTION
units - returns UNITS
hint - returns HINT
enums - returns hash ref {tag => num, ...}
ranges - returns array ref of hash ref [{low=>num, high=>num}]
defaultValue - returns default value
description - returns DESCRIPTION ($SNMP::save_descriptions must
be set prior to MIB initialization/parsing)
&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 netsnmp_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 enumeration 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);
&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 not 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
&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.
Exported SNMP utility functions
&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
Note: utility functions do not support async operation yet.
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 environment variables are set
appropriately (see man mib_api)
Be sure to ensure headers and libraries from old CMU installations are
not being used by mistake (see -NET-SNMP-PATH).
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 email 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.)
Acknowledgments:
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.
Copyright:
[See the COPYING file for the copyright license of Net-SNMP]
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.
Copyright (c) 2003-2006 SPARTA, Inc. All Rights Reserved. This
program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
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