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1 | /* SNMP support | |
2 | * Copyright (C) 2012 Vincent Bernat <bernat@luffy.cx> | |
3 | * | |
4 | * This file is part of GNU Zebra. | |
5 | * | |
6 | * GNU Zebra is free software; you can redistribute it and/or modify it | |
7 | * under the terms of the GNU General Public License as published by the | |
8 | * Free Software Foundation; either version 2, or (at your option) any | |
9 | * later version. | |
10 | * | |
11 | * GNU Zebra is distributed in the hope that it will be useful, but | |
12 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License along | |
17 | * with this program; see the file COPYING; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | */ | |
20 | ||
21 | #include <zebra.h> | |
22 | ||
23 | #ifdef SNMP_AGENTX | |
24 | #include <net-snmp/net-snmp-config.h> | |
25 | #include <net-snmp/net-snmp-includes.h> | |
26 | #include <net-snmp/agent/net-snmp-agent-includes.h> | |
27 | #include <net-snmp/agent/snmp_vars.h> | |
28 | ||
29 | #include "command.h" | |
30 | #include "smux.h" | |
31 | #include "memory.h" | |
32 | #include "linklist.h" | |
33 | #include "version.h" | |
34 | #include "lib_errors.h" | |
35 | ||
36 | static int agentx_enabled = 0; | |
37 | ||
38 | static struct thread_master *agentx_tm; | |
39 | static struct thread *timeout_thr = NULL; | |
40 | static struct list *events = NULL; | |
41 | ||
42 | static void agentx_events_update(void); | |
43 | ||
44 | static int agentx_timeout(struct thread *t) | |
45 | { | |
46 | timeout_thr = NULL; | |
47 | ||
48 | snmp_timeout(); | |
49 | run_alarms(); | |
50 | netsnmp_check_outstanding_agent_requests(); | |
51 | agentx_events_update(); | |
52 | return 0; | |
53 | } | |
54 | ||
55 | static int agentx_read(struct thread *t) | |
56 | { | |
57 | fd_set fds; | |
58 | struct listnode *ln = THREAD_ARG(t); | |
59 | list_delete_node(events, ln); | |
60 | ||
61 | FD_ZERO(&fds); | |
62 | FD_SET(THREAD_FD(t), &fds); | |
63 | snmp_read(&fds); | |
64 | ||
65 | netsnmp_check_outstanding_agent_requests(); | |
66 | agentx_events_update(); | |
67 | return 0; | |
68 | } | |
69 | ||
70 | static void agentx_events_update(void) | |
71 | { | |
72 | int maxfd = 0; | |
73 | int block = 1; | |
74 | struct timeval timeout = {.tv_sec = 0, .tv_usec = 0}; | |
75 | fd_set fds; | |
76 | struct listnode *ln; | |
77 | struct thread *thr; | |
78 | int fd, thr_fd; | |
79 | ||
80 | THREAD_OFF(timeout_thr); | |
81 | ||
82 | FD_ZERO(&fds); | |
83 | snmp_select_info(&maxfd, &fds, &timeout, &block); | |
84 | ||
85 | if (!block) { | |
86 | timeout_thr = NULL; | |
87 | thread_add_timer_tv(agentx_tm, agentx_timeout, NULL, &timeout, | |
88 | &timeout_thr); | |
89 | } | |
90 | ||
91 | ln = listhead(events); | |
92 | thr = ln ? listgetdata(ln) : NULL; | |
93 | thr_fd = thr ? THREAD_FD(thr) : -1; | |
94 | ||
95 | /* "two-pointer" / two-list simultaneous iteration | |
96 | * ln/thr/thr_fd point to the next existing event listener to hit while | |
97 | * fd counts to catch up */ | |
98 | for (fd = 0; fd < maxfd; fd++) { | |
99 | /* caught up */ | |
100 | if (thr_fd == fd) { | |
101 | struct listnode *nextln = listnextnode(ln); | |
102 | if (!FD_ISSET(fd, &fds)) { | |
103 | thread_cancel(thr); | |
104 | list_delete_node(events, ln); | |
105 | } | |
106 | ln = nextln; | |
107 | thr = ln ? listgetdata(ln) : NULL; | |
108 | thr_fd = thr ? THREAD_FD(thr) : -1; | |
109 | } | |
110 | /* need listener, but haven't hit one where it would be */ | |
111 | else if (FD_ISSET(fd, &fds)) { | |
112 | struct listnode *newln; | |
113 | thr = NULL; | |
114 | thread_add_read(agentx_tm, agentx_read, NULL, fd, &thr); | |
115 | newln = listnode_add_before(events, ln, thr); | |
116 | thr->arg = newln; | |
117 | } | |
118 | } | |
119 | ||
120 | /* leftover event listeners at this point have fd > maxfd, delete them | |
121 | */ | |
122 | while (ln) { | |
123 | struct listnode *nextln = listnextnode(ln); | |
124 | thread_cancel(listgetdata(ln)); | |
125 | list_delete_node(events, ln); | |
126 | ln = nextln; | |
127 | } | |
128 | } | |
129 | ||
130 | /* AgentX node. */ | |
131 | static struct cmd_node agentx_node = {SMUX_NODE, | |
132 | "", /* AgentX has no interface. */ | |
133 | 1}; | |
134 | ||
135 | /* Logging NetSNMP messages */ | |
136 | static int agentx_log_callback(int major, int minor, void *serverarg, | |
137 | void *clientarg) | |
138 | { | |
139 | struct snmp_log_message *slm = (struct snmp_log_message *)serverarg; | |
140 | char *msg = XSTRDUP(MTYPE_TMP, slm->msg); | |
141 | if (msg) | |
142 | msg[strlen(msg) - 1] = '\0'; | |
143 | switch (slm->priority) { | |
144 | case LOG_EMERG: | |
145 | flog_err(EC_LIB_SNMP, "snmp[emerg]: %s", msg ? msg : slm->msg); | |
146 | break; | |
147 | case LOG_ALERT: | |
148 | flog_err(EC_LIB_SNMP, "snmp[alert]: %s", msg ? msg : slm->msg); | |
149 | break; | |
150 | case LOG_CRIT: | |
151 | flog_err(EC_LIB_SNMP, "snmp[crit]: %s", msg ? msg : slm->msg); | |
152 | break; | |
153 | case LOG_ERR: | |
154 | flog_err(EC_LIB_SNMP, "snmp[err]: %s", msg ? msg : slm->msg); | |
155 | break; | |
156 | case LOG_WARNING: | |
157 | flog_warn(EC_LIB_SNMP, "snmp[warning]: %s", | |
158 | msg ? msg : slm->msg); | |
159 | break; | |
160 | case LOG_NOTICE: | |
161 | zlog_notice("snmp[notice]: %s", msg ? msg : slm->msg); | |
162 | break; | |
163 | case LOG_INFO: | |
164 | zlog_info("snmp[info]: %s", msg ? msg : slm->msg); | |
165 | break; | |
166 | case LOG_DEBUG: | |
167 | zlog_debug("snmp[debug]: %s", msg ? msg : slm->msg); | |
168 | break; | |
169 | } | |
170 | XFREE(MTYPE_TMP, msg); | |
171 | return SNMP_ERR_NOERROR; | |
172 | } | |
173 | ||
174 | static int config_write_agentx(struct vty *vty) | |
175 | { | |
176 | if (agentx_enabled) | |
177 | vty_out(vty, "agentx\n"); | |
178 | return 1; | |
179 | } | |
180 | ||
181 | DEFUN (agentx_enable, | |
182 | agentx_enable_cmd, | |
183 | "agentx", | |
184 | "SNMP AgentX protocol settings\n") | |
185 | { | |
186 | if (!agentx_enabled) { | |
187 | init_snmp(FRR_SMUX_NAME); | |
188 | events = list_new(); | |
189 | agentx_events_update(); | |
190 | agentx_enabled = 1; | |
191 | } | |
192 | ||
193 | return CMD_SUCCESS; | |
194 | } | |
195 | ||
196 | DEFUN (no_agentx, | |
197 | no_agentx_cmd, | |
198 | "no agentx", | |
199 | NO_STR | |
200 | "SNMP AgentX protocol settings\n") | |
201 | { | |
202 | if (!agentx_enabled) | |
203 | return CMD_SUCCESS; | |
204 | vty_out(vty, "SNMP AgentX support cannot be disabled once enabled\n"); | |
205 | return CMD_WARNING_CONFIG_FAILED; | |
206 | } | |
207 | ||
208 | void smux_init(struct thread_master *tm) | |
209 | { | |
210 | agentx_tm = tm; | |
211 | ||
212 | netsnmp_enable_subagent(); | |
213 | snmp_disable_log(); | |
214 | snmp_enable_calllog(); | |
215 | snmp_register_callback(SNMP_CALLBACK_LIBRARY, SNMP_CALLBACK_LOGGING, | |
216 | agentx_log_callback, NULL); | |
217 | init_agent(FRR_SMUX_NAME); | |
218 | ||
219 | install_node(&agentx_node, config_write_agentx); | |
220 | install_element(CONFIG_NODE, &agentx_enable_cmd); | |
221 | install_element(CONFIG_NODE, &no_agentx_cmd); | |
222 | } | |
223 | ||
224 | void smux_register_mib(const char *descr, struct variable *var, size_t width, | |
225 | int num, oid name[], size_t namelen) | |
226 | { | |
227 | register_mib(descr, var, width, num, name, namelen); | |
228 | } | |
229 | ||
230 | int smux_trap(struct variable *vp, size_t vp_len, const oid *ename, | |
231 | size_t enamelen, const oid *name, size_t namelen, | |
232 | const oid *iname, size_t inamelen, | |
233 | const struct trap_object *trapobj, size_t trapobjlen, | |
234 | uint8_t sptrap) | |
235 | { | |
236 | oid objid_snmptrap[] = {1, 3, 6, 1, 6, 3, 1, 1, 4, 1, 0}; | |
237 | size_t objid_snmptrap_len = sizeof objid_snmptrap / sizeof(oid); | |
238 | oid notification_oid[MAX_OID_LEN]; | |
239 | size_t notification_oid_len; | |
240 | unsigned int i; | |
241 | ||
242 | netsnmp_variable_list *notification_vars = NULL; | |
243 | if (!agentx_enabled) | |
244 | return 0; | |
245 | ||
246 | /* snmpTrapOID */ | |
247 | oid_copy(notification_oid, ename, enamelen); | |
248 | notification_oid[enamelen] = sptrap; | |
249 | notification_oid_len = enamelen + 1; | |
250 | snmp_varlist_add_variable(¬ification_vars, objid_snmptrap, | |
251 | objid_snmptrap_len, ASN_OBJECT_ID, | |
252 | (uint8_t *)notification_oid, | |
253 | notification_oid_len * sizeof(oid)); | |
254 | ||
255 | /* Provided bindings */ | |
256 | for (i = 0; i < trapobjlen; i++) { | |
257 | unsigned int j; | |
258 | oid oid[MAX_OID_LEN]; | |
259 | size_t oid_len, onamelen; | |
260 | uint8_t *val; | |
261 | size_t val_len; | |
262 | WriteMethod *wm = NULL; | |
263 | struct variable cvp; | |
264 | ||
265 | /* Make OID. */ | |
266 | if (trapobj[i].namelen > 0) { | |
267 | /* Columnar object */ | |
268 | onamelen = trapobj[i].namelen; | |
269 | oid_copy(oid, name, namelen); | |
270 | oid_copy(oid + namelen, trapobj[i].name, onamelen); | |
271 | oid_copy(oid + namelen + onamelen, iname, inamelen); | |
272 | oid_len = namelen + onamelen + inamelen; | |
273 | } else { | |
274 | /* Scalar object */ | |
275 | onamelen = trapobj[i].namelen * (-1); | |
276 | oid_copy(oid, name, namelen); | |
277 | oid_copy(oid + namelen, trapobj[i].name, onamelen); | |
278 | oid[onamelen + namelen] = 0; | |
279 | oid_len = namelen + onamelen + 1; | |
280 | } | |
281 | ||
282 | /* Locate the appropriate function and type in the MIB registry. | |
283 | */ | |
284 | for (j = 0; j < vp_len; j++) { | |
285 | if (oid_compare(trapobj[i].name, onamelen, vp[j].name, | |
286 | vp[j].namelen) | |
287 | != 0) | |
288 | continue; | |
289 | /* We found the appropriate variable in the MIB | |
290 | * registry. */ | |
291 | oid_copy(cvp.name, name, namelen); | |
292 | oid_copy(cvp.name + namelen, vp[j].name, vp[j].namelen); | |
293 | cvp.namelen = namelen + vp[j].namelen; | |
294 | cvp.type = vp[j].type; | |
295 | cvp.magic = vp[j].magic; | |
296 | cvp.acl = vp[j].acl; | |
297 | cvp.findVar = vp[j].findVar; | |
298 | /* Grab the result. */ | |
299 | val = cvp.findVar(&cvp, oid, &oid_len, 1, &val_len, | |
300 | &wm); | |
301 | if (!val) | |
302 | break; | |
303 | snmp_varlist_add_variable(¬ification_vars, oid, | |
304 | oid_len, vp[j].type, val, | |
305 | val_len); | |
306 | break; | |
307 | } | |
308 | } | |
309 | ||
310 | ||
311 | send_v2trap(notification_vars); | |
312 | snmp_free_varbind(notification_vars); | |
313 | agentx_events_update(); | |
314 | return 1; | |
315 | } | |
316 | ||
317 | #endif /* SNMP_AGENTX */ |