Net-SNMP MIB_API(3)
NAME
init_mib, add_mibdir, init_mib_internals,
add_module_replacement, read_module, read_mib,
read_all_mibs, read_objid, read_module_node,
get_module_node, snmp_set_mib_warnings,
snmp_set_save_descriptions, shutdown_mib, print_mib,
print_variable, fprint_variable, snprint_variable,
sprint_realloc_variable, print_value, fprint_value,
snprint_value, sprint_realloc_value, print_objid,
fprint_objid, snprint_objid, sprint_realloc_objid,
print_description, fprint_description - mib_api functions
SYNOPSIS
#include
void init_mib(void);
int add_mibdir(const char *dirname);
int add_module_replacement(const char *old_module, const
char *new_module, const char *tag
void init_mib_internals(void);
struct tree *read_module(const char *name);
struct tree *read_mib(const char *filename);
struct tree *read_all_mibs(void);
void shutdown_mib(void);
void print_mib(FILE *fp);
int read_objid(const char *input, oid *output, size_t
*out_len
int get_module_node(const char *name, const char *module,
oid *objidvoid print_variable(const oid *objid, size_t objidlen, const
netsnmp_variable_list *variable
void fprint_variable(FILE *fp, const oid *objid, size_t
objidlenint snprint_variable(char *buf, size_t len, const oid *objid
int sprint_realloc_variable(u_char **buf, size_t *buf_len,
size_t *out_len
void print_value(oid *objid, size_t objidlen, const
netsnmp_variable_list *variable)
void fprint_value(FILE *fp, const oid *objid, size_t
objidlenint snprint_value(char *buf, size_t len, const oid *objid
int sprint_realloc_value(u_char **buf, size_t *buf_len,
size_t *out_len
void print_objid(const oid *objid, size_t objidlen);
void fprint_objid(FILE *fp, const oid *objid, size_t
objidlen V5.4.1 Last change: 06 Mar 2002 1Net-SNMP MIB_API(3)
int snprint_objid(char *buf, size_t len, const oid *objid
int sprint_realloc_objid(u_char **buf, size_t *buf_len,
size_t *out_len
void print_description(oid *objid, size_t objidlen, int
widthvoid fprint_description(FILE *fp, const oid *objid, size_t
objidlenvoid snmp_set_mib_warnings(int level);
void snmp_set_save_descriptions(int save);
DESCRIPTION
The functions dealing with MIB modules fall into four groups. Those dealing with initialisation and shutdown, those that read in and parse MIB files, those that search the MIB tree, and various output routines. Initialisation and Shutdowninit_mib is a convenience function that handles all calls to
add_mibdir, read_module and read_mib for standard applica-
tions. It should be called before any other routine that manipulates or accesses the MIB tree. This routine sets up various internal structures, as well as reading in the default MIB modules, as detailed below.add_mibdir is used to define the range of directory loca-
tions which are searched for files containing MIB modules (one module per file). By default, this will be set to thedirectory /etc/net-snmp/mibs but this can be overridden by
setting the environment variable MIBDIRS to a (colon-
separated) list of directories to search. Note that this does not actually load the MIB modules located in thatdirectory, but is an initialisation step to make them avail-
able. This function returns a count of files found in thedirectory, or a -1 if there is an error.
init_mib_internals sets up the internal structures, prepara-
tory to reading in MIB modules. It should be called afterall calls to add_mibdir, and before and calls to
read_module. This is called automatically if init_mib is
used.shutdown_mib will clear the information that was gathered by
read_module, add_mibdir and add_module_replacement. It is
strongly recommended that one does not invoke shutdown_mib
while there are SNMP sessions being actively managed. Reading and Parsing MIBsadd_module_replacement can be used to allow new MIB modules
to obsolete older ones, without needing to amend the imports clauses of other modules. It takes the names of the old and V5.4.1 Last change: 06 Mar 2002 2Net-SNMP MIB_API(3)
new modules, together with an indication of which portions of the old module are affected. tab(+); lb lb lb l l l. tag + len + load the new module when: NULL + 0 + always (the old module is a strict subset of the new) name + 0 + for the given tagonly name + non-0 + for any identifier with this prefix
It can also be used to handle errors in the module identif-
iers used in MIB import clauses (such as referring toRFC1213 instead of RFC1213-MIB).
read_module locates and parses the module specified,
together with any modules that it imports from, and adds the contents of these modules to the active MIB tree. Note thatadd_mibdir must first be called to add the directory con-
taining the file with the module definition, if this is not in the standard path.By default, the following MIB modules will be loaded: IP-
MIB, IF-MIB, TCP-MIB, UDP-MIB, SNMPv2-MIB, RFC1213-MIB,
UCD-SNMP-MIB. This can be overridden by setting the
environment variable MIBS to a (colon-separated) list of
modules to load. If this variable starts with a plus char-
acter, then the specified modules are added to the default list. Otherwise only those modules listed are loaded (together with any others they import from). If MIBS is setto ALL, read_all_mibs is called to load all the MIB files
found in all the specified MIBDIRS.read_mib parses the file specified, together with any
modules that it imports from, and adds the contents to the active MIB tree. Such a file can contain more then one module, though care must be taken that any imports occur earlier in the file, if they are not to be read from the installed modules. Note that the file specified does not need to be in any of the directories initialised byadd_mibdir (or the default setup), though any imported
modules do.The environment variable MIBFILES can be set to a (colon-
separated) list of files containing MIBs to load.read_objid takes a string containing a textual version of an
object identifier (in either numeric or descriptor form),and transforms this into the corresponding list of sub-
identifiers. This is returned in the output parameter, withthe number of sub-identifiers returned via out_len. When
called, out_len must hold the maximum length of the output
array. This function returns a value of 1 if it succeeds in parsing the string and 0 otherwise. Searching the MIB Treeget_module_node takes a descriptor and the name of a module,
and returns the corresponding oid list, in the same way asread_objid above.
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If the module name is specified as "ANY", then this routine will assume that the descriptor given is unique within thetree, and will return the matching entry. If this assump-
tion is invalid, then the behaviour as to which variable is returned is implementation dependent. Outputprint_mib will print out a representation of the currently
active MIB tree to the specified FILE pointer.print_variable will take an object identifier (as returned
by read_objid or get_module_node) and an instance of such a
variable, and prints to the standard output the textual form of the object identifier together with the value of thevariable. fprint_variable does the same, but prints to the
FILE pointer specified by the initial parameter.snprint_variable prints the same information into the buffer
pointed to by buf which is of length len and returns eitherthe number of characters printed, or -1 if the buffer was
not large enough. In the latter case, buf will typically contained a truncated version of the information (but this behaviour is not guaranteed). This function replaces theobsolete function sprint_variable.
sprint_realloc_variable is the low-level function used to
implement all these functions. It prints to a specified offset in a string buffer. The buf parameter points to apointer to that buffer; buf_len points to a variable holding
the current size of that buffer, and out_len points to a
variable holding the offset to which to print. out_len will
be updated to hold the offset of the character following thelast one added to the buffer. If allow_realloc is 1, the
buffer will be dynamically expanded, as necessary, to holdthe output; the variables pointed to by buf and buf_len will
be updated. If allow_realloc is 0, the buffer will not be
dynamically expanded. sprint_realloc_variable returns 0 if
allow_realloc is 1 and an attempt to allocate memory to
expand the buffer fails, or if allow_realloc is 0 and the
output wouldn't fit in the buffer. Otherwise it returns 1. When using this function you should be careful to call free(3) on *buf when you have finished with it.print_value, fprint_value, snprint_value and
sprint_realloc_value do the same as the equivalent
print_variable routines, but only displaying the value of
the variable, without the corresponding object identifier.print_objid, fprint_objid, snprint_objid, and
sprint_realloc_objid take an object identifier (without an
accompanying variable instance) and print out the textual representation. V5.4.1 Last change: 06 Mar 2002 4Net-SNMP MIB_API(3)
print_description and fprint_description take an object
identifier (as for print_objid above) and print out the
associated DESCRIPTION clause. The width argument gives the
number of subidentifiers of an OID, e.g., .1.3.6 is composed of 3 subidentifiers. Note that there are no corresponding routinessnprint_description or sprint_realloc_description. By
default the parser does not save descriptions since they may be huge. In order to be able to print them, you must callsnmp_set_save_descriptions(1).
In general the parser is silent about what strangenesses it sees in the MIB files. To get warnings reported, callsnmp_set_mib_warnings with a level of 1 (or 2 for even more
warnings). ENVIRONMENT VARIABLES MIBDIRS A colon separated list of directories to searchfor MIB modules. Default: /etc/net-snmp/snmp/mibs
MIBFILES A colon separated list of files to load. Default: (none) MIBS A colon separated list of MIB modules to load.Default: IP-MIB:IF-MIB:TCP-MIB:UDP-MIB:SNMPv2-
MIB:RFC1213-MIB:UCD-SNMP-MIB.
SEE ALSO
snmp_api(3)
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:box; cbp-1 | cbp-1 l | l . ATTRIBUTE TYPE ATTRIBUTE VALUE =
Availability system/management/snmp/net-snmp = Interface
Stability Volatile NOTESSource for net-snmp is available on http://opensolaris.org.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:box; cbp-1 | cbp-1 l | l . ATTRIBUTE TYPE ATTRIBUTE VALUE =
Availability system/management/snmp/net-snmp = Interface
Stability Volatile NOTESSource for net-snmp is available on http://opensolaris.org.
V5.4.1 Last change: 06 Mar 2002 5Net-SNMP MIB_API(3)
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:_______________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|____________________|__________________________________|_
| Availability | system/management/snmp/net-snmp|
|____________________|__________________________________|_
| Interface Stability| Volatile ||____________________|_________________________________|
NOTESSource for net-snmp is available on http://opensolaris.org.
V5.4.1 Last change: 06 Mar 2002 6