1MIB_API(3) Net-SNMP MIB_API(3)
2
6 init_mib, add_mibdir, init_mib_internals, shutdown_mib, net‐
7 snmp_read_module, read_mib, read_all_mibs, add_module_replacement,
8 read_objid, snmp_parse_oid, get_module_node, snmp_set_mib_errors,
9 snmp_set_mib_warnings, snmp_set_save_descriptions, print_mib,
10 print_objid, fprint_objid, snprint_objid, print_description,
11 fprint_description, snprint_description - mib_api functions
12
14 #include <net-snmp/mib_api.h>
15 void init_mib(void);
17 int add_mibdir(const char *dirname);
19 void init_mib_internals(void);
20 void shutdown_mib(void);
22 Reading and Parsing MIBs
24 struct tree *netsnmp_read_module(const char *name);
25 struct tree *read_mib(const char *filename);
26 struct tree *read_all_mibs(void);
27 int add_module_replacement(const char *old_module,
29 const char *new_module,
30 const char *tag, int len);
31 void snmp_set_mib_warnings(int level);
33 void snmp_set_mib_errors( int level);
34 void snmp_set_save_descriptions(int save);
35 Searching the MIB Tree
37 int read_objid(const char *input,
38 oid *objid, size_t *objidlen);
39 oid *snmp_parse_oid(const char *input,
40 oid *objid, size_t *objidlen);
41 int get_module_node(const char *name, const char *module,
42 oid *objid, size_t *objidlen);
43 Output
45 void print_mib(FILE *fp);
46 void print_objid(const oid *objid, size_t objidlen);
48 void fprint_objid(FILE *fp,
49 const oid *objid, size_t objidlen);
50 int snprint_objid(char *buf, size_t len,
51 const oid *objid, size_t objidlen);
52 void print_description(const oid *objid, size_t objidlen, int width);
54 void fprint_description(FILE *fp,
55 const oid *objid, size_t objidlen, int width);
56 int snprint_description(char *buf, size_t len,
57 const oid *objid, size_t objidlen, int width);
58
60 The functions dealing with MIB modules fall into four groups - those
61 dealing with initialisation and shutdown, with reading in and parsing
62 MIB files, with searching the MIB tree, and output routines.
63 Initialisation and Shutdown
65 add_mibdir is used to add the specified directory to the path of loca‐
66 tions which are searched for files containing MIB modules. Note that
67 this does not actually load the MIB modules located in that directory,
68 but is simply an initialisation step to make them available to net‐
69 snmp_read_module. This function returns a count of files found in the
70 directory, or a -1 if there is an error.
71 init_mib_internals sets up the internal structures, preparatory to
73 reading in MIB modules. It should be called after all calls to
74 add_mibdir, and before any calls to netsnmp_read_module.
75 init_mib is a convenience function that configures the MIB directory
77 search path (using add_mibdir ), set up the internal MIB framework
78 (using init_mib_internals ), and then loads the appropriate MIB modules
79 (using netsnmp_read_module and read_mib). See the ENVIRONMENTAL VARI‐
80 ABLES section for details.
81 It should be called before any other routine that manipulates or
82 accesses the MIB tree.
83 shutdown_mib will clear the information that was gathered by net‐
85 snmp_read_module, add_mibdir and add_module_replacement. It is
86 strongly recommended that one does not invoke shutdown_mib while there
87 are SNMP sessions being actively managed.
88 Reading and Parsing MIBs
90 netsnmp_read_module takes the name of a MIB module (which need not be
91 the same as the name of the file that contains the module), locates
92 this within the configured list of MIB directories, and loads the defi‐
93 nitions from the module into the active MIB tree. It also loads any
94 MIB modules listed in the IMPORTS clause of this module.
95 read_mib is similar, but takes the name of the file containing the MIB
97 module. Note that this file need not be located within the MIB direc‐
98 tory search list (although any modules listed in the IMPORTS clause
99 do).
100 read_all_mibs will read in all the MIB modules found on the MIB direc‐
102 tory search list.
103 In general the parser is silent about what strangenesses it sees in the
105 MIB files. To get warnings reported, call snmp_set_mib_warnings with a
106 level of 1 (or 2 for even more warnings).
107 add_module_replacement can be used to allow new MIB modules to obsolete
109 older ones, without needing to amend the IMPORTS clauses of other mod‐
110 ules. It takes the names of the old and new modules, together with an
111 indication of which portions of the old module are affected.
112 tag len load the new module when:
114 NULL 0 always (the old module is a strict subset of the new)
115 name 0 for the given tag only
116 name non-0 for any identifier with this prefix
117 It can also be used to handle errors in the module identifiers used in
118 MIB IMPORTS clauses (such as referring to RFC1213 instead of
119 RFC1213-MIB).
120 Searching the MIB Tree
122 read_objid takes a string containing a textual version of an object
123 identifier (in either numeric or descriptor form), and transforms this
124 into the corresponding list of sub-identifiers. This is returned in
125 the output parameter, with the number of sub-identifiers returned via
126 out_len. When called, out_len must hold the maximum length of the out‐
127 put array. If multiple object identifiers are being processed, then
128 this length should be reset before each call. This function returns a
129 value of 1 if it succeeds in parsing the string and 0 otherwise.
130 snmp_parse_oid is similar, but returns a pointer to the parsed OID buf‐
132 fer (or NULL).
133 get_module_node takes a descriptor and the name of a module, and
135 returns the corresponding oid list, in the same way as read_objid
136 above.
137 If the module name is specified as "ANY", then this routine will assume
138 that the descriptor given is unique within the tree, and will return
139 the matching entry. If this assumption is invalid, then the behaviour
140 as to which variable is returned is implementation dependent.
141 Output
143 print_mib will print out a representation of the currently active MIB
144 tree to the specified FILE pointer.
145 print_objid will take an object identifier (as returned by read_objid,
147 snmp_parse_oid or get_module_node), and prints the textual form of this
148 OID to the standard output.
149 fprint_objid does the same, but prints to the FILE pointer specified by
151 the initial parameter.
152 snprint_objid prints the same information into the buffer pointed to by
154 buf which is of length len. It returns the number of characters
155 printed, or -1 if the buffer was not large enough. In the latter case,
156 buf will typically contain a truncated version of the information (but
157 this behaviour is not guaranteed).
158 print_description, fprint_description, and snprint_description take a
160 similar object identifier and print out a version of the MIB definition
161 for that object, together with the full OID. The width argument con‐
162 trols how the OID is layed out.
163 By default the parser does not save descriptions since they may be
165 huge. In order to be able to print them, it is necessary to invoke
166 snmp_set_save_descriptions(1)before calling init_mib (or similar).
167
169 The main use of environmental variables with respect to these API calls
170 is to configure which MIB modules should be loaded, and where they are
171 located.
172 MIBDIRS A colon separated list of directories to search for MIB mod‐
174 ules.
175 Default: /usr/share/snmp/mibs
176 Used by init_mib, netsnmp_read_module, read_all_mibs and
177 (implicitly) by read_mib.
178 MIBS A colon separated list of MIB modules to load.
180 The default list of modules will depend on how the Net-SNMP
181 software was originally compiled, but is typically: IP-
182 MIB:IF-MIB:TCP-MIB:UDP-MIB:SNMPv2-MIB:RFC1213-MIB:UCD-SNMP-
183 MIB:HOST-RESOURCES-MIB
184 If the value of the MIBS environmental variable starts with a
186 '+' character, then these MIB modules will be added to the
187 default list. Otherwise these modules (plus any that they
188 IMPORT from) will be loaded instead of the default list.
189 If the MIBS environmental variable has the value ALL then
191 read_all_mibs will be called to load the full collection of
192 all available MIB modules.
193 Used by init_mib only.
195 MIBFILES A colon separated list of files to load.
197 Default: (none)
198 Used by init_mib only.
199
201 snmp_api(3), output_api(3)
2024.2 Berkeley Distribution 06 Mar 2002 MIB_API(3)