GENSNMPTREE(1) FreeBSD General Commands Manual GENSNMPTREE(1)


gensnmptreegenerate C and header files from a MIB description file


gensnmptree [ -dEehlt][ -I directory][ -i infile][ -p prefix][ name ...]


The gensnmptree utility is used to either generate C language tables and header files from a MIB description or to numeric OIDs from MIB descriptions. The first form is used only for maintaining the bsnmpd(1) daemon or for module writers. The second form may be used by SNMP client program writers.

If none of the options -e, -E or -t are used gensnmptree reads a MIB description from its standard input and creates two files: a C-file prefixtree.c containing a table used by bsnmpd(1) during PDU processing and a header file prefixtree.h containing appropriate declarations of the callback functions used in this table, the table itself and definitions for all enums.

The following options are available:

Switch on debugging.
Extract enumerations and bit constructs. In this mode the tool emits a header file that contains for each type given on the command line a C-enum definition and a preprocessor define that may be used to map values to strings.
gensnmptree expects MIB variable names (only the last component) on its command line. It reads a MIB specification from standard input and for each MIB variable name emits three C preprocessor defines on its standard output:
OIDX_ name
This define can be used to initialize a struct asn_oid in the following way:

const struct asn_oid oid_sysDescr = OIDX_sysDescr;
OIDLEN_ name
is the length of the OID.
OID_ name
is the last component of the OID.
Print a short help page.
-I directory
Add the named directory to the include path just before the standard include directories.
-i infile
Read from the named file instead of standard input.
Generate local preprocessor includes. This is used for bootstrapping bsnmpd(1).
Instead of normal output print the resulting tree.
-p prefix
Prefix the file names and the table name with prefix.


The syntax of the MIB description file can formally be specified as follows:

 file := top | top file 
 top := tree | typedef | include 
 tree := head elements ')' 
 entry := head ':' index STRING elements ')' 
 leaf := head type STRING ACCESS ')' 
 column := head type ACCESS ')' 
 type := BASETYPE | BASETYPE '|' subtype | enum | bits 
 subtype := STRING 
 enum := ENUM '(' value ')' 
 bits := BITS '(' value ')' 
 value := INT STRING | INT STRING value 
 head := '(' INT STRING 
 elements := EMPTY | elements element 
 element := tree | leaf | column 
 index := type | index type 
 typedef := 'typedef' STRING type 
 include := 'include' filespec 
 filespec := '"' STRING '"' | '<' STRING '>'

BASETYPE specifies a SNMP data type and may be one of

  • NULL
  • INTEGER32 (same as INTEGER)
  • UNSIGNED32 (same as GAUGE)
  • OID

ACCESS specifies the accessibility of the MIB variable (which operation can be performed) and is one of

  • GET
  • SET

INT is a decimal integer and STRING is any string starting with a letter or underscore and consisting of letters, digits, underscores and minuses, that is not one of the keywords.

The typedef directive associates a type with a single name.

The include directive is replaced by the contents of the named file.


The following MIB description describes the system group:

include "tc.def" 
typedef AdminStatus ENUM ( 
 1 up 
 2 down 
(1 internet 
  (2 mgmt 
    (1 mibII 
      (1 system 
        (1 sysDescr OCTETSTRING op_system_group GET) 
        (2 sysObjectId OID op_system_group GET) 
        (3 sysUpTime TIMETICKS op_system_group GET) 
        (4 sysContact OCTETSTRING op_system_group GET SET) 
        (5 sysName OCTETSTRING op_system_group GET SET) 
        (6 sysLocation OCTETSTRING op_system_group GET SET) 
        (7 sysServices INTEGER op_system_group GET) 
        (8 sysORLastChange TIMETICKS op_system_group GET) 
        (9 sysORTable 
          (1 sysOREntry : INTEGER op_or_table 
            (1 sysORIndex INTEGER) 
            (2 sysORID OID GET) 
            (3 sysORDescr OCTETSTRING GET) 
            (4 sysORUpTime TIMETICKS GET) 




Hartmut Brandt <harti@FreeBSD.org>
May 26, 2006 FreeBSD