2 .\" Copyright (c) 2004-2005
4 .\" All rights reserved.
5 .\" Copyright (c) 2001-2003
6 .\" Fraunhofer Institute for Open Communication Systems (FhG Fokus).
7 .\" All rights reserved.
9 .\" Author: Harti Brandt <harti@FreeBSD.org>
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12 .\" modification, are permitted provided that the following conditions
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32 .\" $Begemot: bsnmp/snmp_mibII/snmp_mibII.3,v 1.10 2005/10/04 08:46:52 brandt_h Exp $
42 .Nm mib_refresh_iflist ,
45 .Nm mib_find_if_name ,
48 .Nm mib_register_newif ,
49 .Nm mib_unregister_newif ,
55 .Nm mib_ifstack_create ,
56 .Nm mib_ifstack_delete ,
57 .Nm mib_find_rcvaddr ,
58 .Nm mib_rcvaddr_create ,
59 .Nm mib_rcvaddr_delete ,
62 .Nd "mib-2 module for bsnmpd."
64 .Pq begemotSnmpdModulePath."mibII" = "@MODPATH@snmp_mibII.so"
69 .In bsnmp/snmp_mibII.h
71 .Fn (*mibif_notify_f) "struct mibif *ifp" "enum mibif_notify event" "void *uarg"
72 .Vt extern int mib_netsock ;
74 .Fn mib_if_set_dyn "const char *ifname"
76 .Fn mib_refresh_iflist "void"
78 .Fn mib_find_if "u_int ifindex"
80 .Fn mib_find_if_sys "u_int sysindex"
82 .Fn mib_find_if_name "const char *ifname"
84 .Fn mib_first_if "void"
86 .Fn mib_next_if "const struct mibif *ifp"
88 .Fn mib_register_newif "int (*func)(struct mibif *)" "const struct lmodule *mod"
90 .Fn mib_unregister_newif "const struct lmodule *mod"
92 .Fn mib_fetch_ifmib "struct mibif *ifp"
94 .Fn mib_if_admin "struct mibif *ifp" "int up"
96 .Fn mib_find_ifa "struct in_addr ipa"
98 .Fn mib_first_ififa "const struct mibif *ifp"
100 .Fn mib_next_ififa "struct mibifa *ifa"
102 .Fn mib_ifstack_create "const struct mibif *lower" "const struct mibif *upper"
104 .Fn mib_ifstack_delete "const struct mibif *lower" "const struct mibif *upper"
105 .Ft struct mibrcvaddr *
106 .Fn mib_find_rcvaddr "u_int ifindex" "const u_char *addr" "size_t addrlen"
107 .Ft struct mibrcvaddr *
108 .Fn mib_rcvaddr_create "struct mibif *ifp" "const u_char *addr" "size_t addrlen"
110 .Fn mib_rcvaddr_delete "struct mibrcvaddr *addr"
112 .Fn mibif_notify "struct mibif *ifp" "const struct lmodule *mod" "mibif_notify_f func" "void *uarg"
114 .Fn mibif_unnotify "void *reg"
118 module implements parts of the internet standard MIB-2.
119 Most of the relevant MIBs are implemented.
120 Some of the tables are restricted to be read-only instead of read-write.
121 The exact current implementation can be found in
122 .Pa @DEFPATH@mibII_tree.def .
123 The module also exports a number of functions and global variables for use
124 by other modules, that need to handle network interfaces.
125 This man page describes these functions.
126 .Ss DIRECT NETWORK ACCESS
129 module opens a socket that is used to execute all network related
132 This socket is globally available under the name
134 .Ss NETWORK INTERFACES
137 module handles a list of all currently existing network interfaces.
139 other modules to handle their own interface lists with special information
140 by providing a mechanism to register to events that change the interface list
142 The basic data structure is the interface structure:
143 .Bd -literal -offset indent
145 TAILQ_ENTRY(mibif) link;
147 u_int index; /* logical ifindex */
151 struct ifmibdata mib;
159 uint64_t counter_disc;
160 mibif_notify_f xnotify;
162 const struct lmodule *xnotify_mod;
163 struct asn_oid spec_oid;
169 module tries to implement the semantic if
171 as described in RFC-2863.
172 This RFC states, that an interface indexes may not be reused.
173 That means, for example, if
175 is a synthetic interface type and the system creates the interface
177 destroys this interfaces and again creates a
179 then these interfaces must have different interface indexes, because in fact
180 they are different interfaces.
181 If, on the other hand, there is a hardware interface
183 and this interface disappears, because its driver is unloaded and appears
184 again, because the driver is loaded again, the interface index must stay
187 implements this by differentiating between real and synthetic (dynamic)
189 An interface type can be declared dynamic by calling the function
191 with the name if the interface type (for example
193 For real interfaces, the module keeps the mapping between the interface name
196 in a special list, if the interface is unloaded.
197 For dynamic interfaces
200 is generated each time the interface comes into existence.
201 This means, that the interface index as seen by SNMP is not the same index
202 as used by the system.
207 the system's interface index is
211 .Nm mib_refresh_iflist
212 causes the entire interface list to be re-created.
214 The interface list can be traversed with the functions
218 Be sure not to change the interface list while traversing the list with
221 There are three functions to find an interface by name or index.
223 finds an interface by searching for an SNMP
226 finds an interface by searching for a system interface index and
228 finds an interface by looking for an interface name.
229 Each of the function returns
231 if the interface cannot be found.
235 causes the interface MIB to be refreshed from the kernel.
239 can be used to change the interface administrative state to up
240 (argument is 1) or down (argument is 0).
242 A module can register itself to receive a notification when a new entry is
243 created in the interface list.
244 This is done by calling
245 .Fn mib_register_newif .
246 A module can register only one function, a second call to
247 .Fn mib_register_newif
248 causes the registration to be overwritten.
249 The registration can be removed with a call to
250 .Fn mib_unregister_newif .
251 It is unregistered automatically, when the registering module is unloaded.
253 A module can also register to events on a specific interface.
254 This is done by calling
256 This causes the given callback
258 to be called with the interface pointer, a notification code and
261 when any of the following events occur:
262 .Bl -tag -width "XXXXX"
263 .It Li MIBIF_NOTIFY_DESTROY
264 The interface is destroyed.
267 This mechanism can be used to implement interface type specific MIB parts
269 The registration can be removed with
271 which the return value from
273 Any notification registration is removed automatically when the interface
274 is destroyed or the registering module is unloaded.
275 .Em Note that only one module can register to any given interface .
276 .Ss INTERFACE ADDRESSES
279 module handles a table of interface IP-addresses.
280 These addresses are held in a
281 .Bd -literal -offset indent
283 TAILQ_ENTRY(mibifa) link;
284 struct in_addr inaddr;
285 struct in_addr inmask;
286 struct in_addr inbcast;
287 struct asn_oid index;
293 The (ordered) list of IP-addresses on a given interface can be traversed by
298 The list should not be considered read-only.
299 .Ss INTERFACE RECEIVE ADDRESSES
300 The internet MIB-2 contains a table of interface receive addresses.
301 These addresses are handled in:
302 .Bd -literal -offset indent
304 TAILQ_ENTRY(mibrcvaddr) link;
305 struct asn_oid index;
307 u_char addr[ASN_MAXOIDLEN];
312 MIBRCVADDR_VOLATILE = 0x00000001,
313 MIBRCVADDR_BCAST = 0x00000002,
314 MIBRCVADDR_HW = 0x00000004,
318 Note, that the assignment of
320 is based on a list of known interface types.
321 The flags should be handled
322 by modules implementing interface type specific MIBs.
324 A receive address can be created with
325 .Fn mib_rcvaddr_create
327 .Fn mib_rcvaddr_delete .
328 This needs to be done only for addresses that are not automatically handled
331 A receive address can be found with
332 .Fn mib_find_rcvaddr .
333 .Ss INTERFACE STACK TABLE
336 module maintains also the interface stack table.
337 Because for complex stacks,
338 there is no system supported generic way of getting this information, interface
339 type specific modules need to help setting up stack entries.
342 module handles only the top and bottom entries.
344 A table entry is created with
345 .Fn mib_ifstack_create
347 .Fn mib_ifstack_delete .
348 Both functions need the pointers to the interfaces.
349 Entries are automatically
350 deleted if any of the interfaces of the entry is destroyed.
352 both the stack table and the reverse stack table.
354 .Bl -tag -width ".It Pa @DEFPATH@mibII_tree.def" -compact
355 .It Pa @DEFPATH@mibII_tree.def
356 The description of the MIB tree implemented by
358 .It Pa /usr/local/share/snmp/mibs
360 The various internet MIBs.
366 This implementation conforms to the applicable IETF RFCs.
368 .An Hartmut Brandt Aq harti@FreeBSD.org