mib2c
MIB2C(1) Net-SNMP MIB2C(1)
NAME
mib2c -- generate template code for extending the agent
SYNOPSIS
mib2c [-h] -c CONFIGFILE [-I PATH] [-f OUTNAME] [-i][-s][-q][-S VAR=VAL]
MIBNODE
DESCRIPTION
The mib2c tool is designed to take a portion of the MIB tree (as defined
by a MIB file) and generate the template C code necessary to implement
the relevant management objects within it.
In order to implement a new MIB module, three files are necessary:
- MIB definition file
- C header file
- C implementation file.
The mib2c tool uses the MIB definition file to produce the two C code
files. Thus, mib2c generates a template that you can edit to add logic
necessary to obtain information from the operating system or application
to complete the module.
MIBNODE is the top level mib node you want to generate code for. You
must give mib2c a mib node (e.g. ifTable) on the command line, not a mib
file. This is the single most common mistake.
The mib2c tool accepts both SMIv1 and SMIv2 MIBs.
mib2c needs to be able to find and load a MIB file in order to generate C
code for the MIB. To enable mib2c to find the MIB file, set the MIBS
environment variable to include the MIB file you are using. An example
of setting this environment variable is:
MIBS=+NET-SNMP-TUTORIAL-MIB
or
MIBS=ALL
The first example ensures that mib2c finds the NET-SNMP-TUTORIAL-MIB mib,
in addition to the default MIB modules. The default list of MIB modules
is set when the suite is first configured and built and basically
corresponds to the list of modules that the agent supports. The second
example ensures that mib2c finds all MIBs in the search location for MIB
files. The default search location for MIB files is /usr/share/snmp/mibs.
This search location can be modified by the MIBDIRS environment variable.
Both the MIB files to be loaded and the MIB file search location can also
be configured in the snmp.conf file. Please see snmp.conf(5) for more
information.
The generated *.c and *.h files will be created in the current working
directory.
OPTIONS
-h Display a help message.
-c CONFIGFILE
Use CONFIGFILE when generating code. These files will be searched
for first in the current directory and then in the /usr/share
directory (which is where the default mib2c configuration files
can be found). Running mib2c without the -c CONFIGFILE option
will display a description of the valid values for CONFIGFILE,
that is, the available config files, including new ones that you
might author.
For example,
% mib2c ifTable
will display a description of the currently available values for
CONFIGFILE.
The following values are supported for CONFIGFILE:
mib2c.mfd.conf
mib2c.scalar.conf
mib2c.int_watch.conf
mib2c.iterate.conf
mib2c.create-dataset.conf
mib2c.array-user.conf
mib2c.column_defines.conf
mib2c.column_enums.conf
GENERATING CODE FOR SCALAR OBJECTS:
If you're writing code for some scalars, run:
mib2c -c mib2c.scalar.conf MIBNODE
If you want to magically "tie" integer variables to integer
scalars, use:
mib2c -c mib2c.int_watch.conf MIBNODE
GENERATING CODE FOR TABLES:
The recommended configuration file for tables is the MIBs for
Dummies, or MFD, configuration file. It hides as much of the SNMP
details as possible, generating small, easy to understand
functions. It is also the most flexible and well documented
configuration file. See the agent/mibgroup/if-
mib/ifTable/ifTable*.c files for an example:
mib2c -c mib2c.mfd.conf MIBNODE
If your table data is kept somewhere else (e.g. it's in the kernel
and not in the memory of the agent itself) and you need to
"iterate" over it to find the right data for the SNMP row being
accessed. See the agent/mibgroup/mibII/vacm_context.c file for an
example:
mib2c -c mib2c.iterate.conf MIBNODE
If your table data is kept in the agent (i.e. it's not located in
an external source) and is purely data driven (i.e. you do not
need to perform any work when a set occurs). See the
agent/mibgroup/examples/data_set.c file for an example of such a
table:
mib2c -c mib2c.create-dataset.conf MIBNODE
If your table data is kept in the agent (i.e. it's not located in
an external source), and you can keep your data sorted by the
table index but you do need to perform work when a set occurs:
mib2c -c mib2c.array-user.conf MIBNODE
GENERATING HEADER FILE DEFINITIONS
To generate just a header with a define for each column number in
your table:
mib2c -c mib2c.column_defines.conf MIBNODE
To generate just a header with a define for each enum for any
column containing enums:
mib2c -c mib2c.column_enums.conf MIBNODE
GENERATING CODE FOR THE 4.X LINE OF CODE (THE OLDER API)
mib2c -c mib2c.old-api.conf MIBNODE
-IPATH Search for configuration files in PATH. Multiple paths can be
specified using multiple -I switches or by using one with a comma
separated list of paths in it.
-f OUTNAME
Places the output code into OUTNAME.c and OUTNAME.h. Normally,
mib2c will place the output code into files which correspond to
the table names it is generating code for, which is probably what
you want anyway.
-i Do not run indent on the resulting code.
-s Do not look for MIBNODE.sed and run sed on the resulting code.
This is useful to shorten long mib variable names in the code.
-q Run in "quiet" mode, which minimizes the status messages mib2c
generates.
-SVAR=VAL
Preset a variable VAR, in the mib2c.*.conf file, to the value VAL.
None of the existing mib2c configuration files (mib2c.*.conf)
currently makes use of this feature, however, so this option
should be considered available only for future use.
EXAMPLES
The following generates C template code for the header and implementation
files to implement UCD-DEMO-MIB::ucdDemoPublic.
% mib2c -c mib2c.scalar.conf ucdDemoPublic
writing to ucdDemoPublic.h
writing to ucdDemoPublic.c
running indent on ucdDemoPublic.h
running indent on ucdDemoPublic.c
The resulting ucdDemoPublic.c and ucdDemoPublic.h files are generated the
current working directory.
The following generates C template code for the header and implementation
files for the module to implement TCP-MIB::tcpConnTable.
% mib2c -c mib2c.iterate.conf tcpConnTable
writing to tcpConnTable.h
writing to tcpConnTable.c
running indent on tcpConnTable.h
running indent on tcpConnTable.c
The resulting tcpConnTable.c and tcpConnTable.h files are generated in
the current working directory.
SEE ALSO
snmpcmd(1), snmp.conf(5)
V5.6.2.1 05 Apr 2010 MIB2C(1)