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This README describes the ./local/mib2c script.
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Author: Derek Simkowiak
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(please mail questions to net-snmp-coders@lists.sourceforge.net,
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not to the author directly. Thanks!)
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Date: Wed Jan 20 02:51:06 PST 1999
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-----------------------------------------------------------------------
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mib2c is a Perl script that takes a MIB (such as those files found
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in ./mibs/ ) and converts it into C code. That C code can then be used as a
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"template" to implement your MIB. Then, when you are done editing the C
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code and recompiling, the UCD-SNMP agent (snmpd) will support your MIB.
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mib2c takes the place of "MIB Compilers" that come with commercial SNMP
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REQUIREMENTS/INSTALLATION
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mib2c requires the SNMP.pm Perl module. As of this writing the
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latest version of the SNMP.pm module is 1.8.
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The SNMP.pm module can be downloaded from CPAN at
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http://www.cpan.org/modules/by-module/SNMP/
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...the file that you want is probably SNMP-1.8b5.tar.gz .
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If you didn't know that already, most every Perl module can be downloaded
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from CPAN (www.cpan.org). Follow the installation instructions for the
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NOTE: If you are running Redhat Linux 5.2 (and perhaps other
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versions), you might get the following errors during the "make test" phase
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of the installation of the SNMP.pm module:
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[root@olly SNMP-1.8b5]# make test # This is the command...
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PERL_DL_NONLAZY=1 /usr/bin/perl -I./blib/arch -I./blib/lib
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-I/usr/lib/perl5/i386-linux/5.00404 -I/usr/lib/perl5 -e 'use Test::Harness
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qw(&runtests $verbose); $verbose=0; runtests @ARGV;' t/*.t
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t/mib...............ok
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t/session...........FAILED tests 7-8
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Failed 2/14 tests, 85.71% okay
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t/translate.........ok
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Failed Test Status Wstat Total Fail Failed List of failed
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-------------------------------------------------------------------------------
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t/session.t 14 2 14.29% 7-8
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Failed 1/3 test scripts, 66.67% okay. 2/24 subtests failed, 91.67% okay.
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make: *** [test_dynamic] Error 9
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If the "make" went okay, then you can ignore these test failures.
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These indicate you don't have write access to the portions of the mib
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tree that the test script is trying to use. Please don't email the
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UCD-SNMP list with other errors regarding the SNMP.pm module.
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comp.lang.perl.modules is probably the most appropriate spot to
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discuss problems with the SNMP.pm perl module itself. Interelated
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problems between net-snmp and SNMP could be discussed on the net-snmp
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mib2c takes one argument: an OID. It then traces down that OID
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and generates the template C code. Here is the documentation, from the
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# This program, given an OID reference as an argument, creates some
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# template mib module files to be used with the net-snmp agent. It is
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# far from perfect and will not generate working modules, but it
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# significantly shortens development time by outlining the basic
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# Its up to you to verify what it does and change the default values
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# You *must* correct the beginning of the var_XXX() function to
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# correctly determine mib ownership of the incoming request.
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Before you can specify the OID for your enterprise/MIB on the
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command line, the script needs to be able to find your MIB so that it can
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read it in and generate template code. Joe Marzot (gmarzot@nortelnetworks.com)
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--------------------------------------
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you should read (man mib_api). The default behaviour for mib loading
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from within the perl interface uses the environment variables described
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there. You can also override these and explicitly define mibdirs and
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load modules through the perl/SNMP api.
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the easiest thing to do is toss the mibs in /usr/local/share/snmp/mibs
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and set the env. var., MIBS, to 'ALL'.
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--------------------------------------
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I recommend following the last two lines of advice. I simply did
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# cp /home/dereks/MY-MIB-FILE.txt /usr/local/share/snmp/mibs/
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...on my Redhat system (with a BASH shell) and it was able to find
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Here are some examples from Wes Hardaker (wjhardaker@ucdavis.edu).
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He's using a C shell. Wes writes:
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--------------------------------------
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Ok, in order to run the thing, you actually need to do something like
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setenv MIBS MY-ITEM-MIB # assumes csh
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Where, "itemNode" should be a node in the mib tree that you want to
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generate C code for. Note, pick small pieces not large ones. Yes, it
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will generate code for the entire mibII tree if you ask it to, in one
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outputing to interfaces.c and interfaces.h ...
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Number of Lines Created:
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% mib2c mib-2 # Don't ever do this.
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outputing to mib-2.c and mib-2.h ...
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Number of Lines Created:
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It may have some sorting problems with multiple level mib tree
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branches being generated into one piece of code (reorder the .h file
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structure to be in OID lexical order if needed).
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--------------------------------------
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WHAT TO DO WITH THE CODE THAT GETS GENERATED
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You will need to edit your generated code to work with your
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hardware. For instance, if your MIB is for a refrigerator, you will need
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to write the code that talks to the refridgerator (through the serial
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port, maybe?) in Fridge Protocol.
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See the files in ./agent/mibgroup/examples/ and
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./agent/mibgroup/dummy/ for heavily-commented example code. Don't ask me
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questions about this stuff--I'm just now figuring it out myself...
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[NOTE: If anyone out there has tips about necessary options to
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./configure, or re-compiling snmpd with custom MIB support, please add
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As of this writing, the mib2c compiler is a bit outdated and needs
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some work. Wes writes:
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--------------------------------------
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It already needs changing, because the architecture has changed in the
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3.6 line (though its backwards compatible, I'd prefer to generate
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code from newer models than older ones).
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--------------------------------------
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When I asked him to elaborate on the new 3.6 archictecture, all I
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--------------------------------------
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It hopefully will be in the new documentation about mib module api
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that Dave Shield is putting together (which is also currently wrong,
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--------------------------------------
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...so I don't know what the hell he's talking about.
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SOME ERRORS AND THEIR MEANING
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If you get a large number of errors that look like:
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unknown type: INTEGER for prIndex
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unknown type: OCTETSTR for prNames
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unknown type: INTEGER for prMin
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...then you are trying to use an old version of the mib2c script
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that does not support the SNMP.pm module version 1.8. Get the latest
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version of the script.
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Couldn't find mib reference: myEnterpriseOID
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...when you know that it should be finding your MIB file(s), then
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you forgot to put the word "END" at the very end of your MIB. (Uh...I'm
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not speaking from experience here. Really.)
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Many thanks to the people on the UCD-SNMP mailing list
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(net-snmp-users@lists.sourceforge.net). In particular, many thanks to
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Wes Hardaker <wjhardaker@ucdavis.edu>
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Ken McNamara <conmara@tcon.net>
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Joe Marzot <gmarzot@nortelnetworks.com>
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...since about half this document is just cut'n'pasted from emails
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Good luck with your project.
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http://www.kd-dev.com
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local/README.mib2c
