lib/agentx.c

   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
  17  * along with GNU Zebra; see the file COPYING.  If not, write to the Free
  18  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  19  * 02111-1307, USA.
  20  */
  21
  22 #include <zebra.h>
  23
  24 #if defined HAVE_SNMP && defined SNMP_AGENTX
  25 #include <net-snmp/net-snmp-config.h>
  26 #include <net-snmp/net-snmp-includes.h>
  27 #include <net-snmp/agent/net-snmp-agent-includes.h>
  28 #include <net-snmp/agent/snmp_vars.h>
  29
  30 #include "command.h"
  31 #include "smux.h"
  32 #include "memory.h"
  33 #include "linklist.h"
  34
  35 static int agentx_enabled = 0;
  36
  37 static struct thread_master *agentx_tm;
  38 static struct thread *timeout_thr = NULL;
  39 static struct list *events = NULL;
  40
  41 static void agentx_events_update(void);
  42
  43 static int
  44 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
  56 agentx_read(struct thread *t)
  57 {
  58   fd_set fds;
  59   struct listnode *ln = THREAD_ARG (t);
  60   list_delete_node (events, ln);
  61
  62   FD_ZERO (&fds);
  63   FD_SET (THREAD_FD (t), &fds);
  64   snmp_read (&fds);
  65
  66   netsnmp_check_outstanding_agent_requests ();
  67   agentx_events_update ();
  68   return 0;
  69 }
  70
  71 static void
  72 agentx_events_update(void)
  73 {
  74   int maxfd = 0;
  75   int block = 1;
  76   struct timeval timeout = { .tv_sec = 0, .tv_usec = 0 };
  77   fd_set fds;
  78   struct listnode *ln;
  79   struct thread *thr;
  80   int fd, thr_fd;
  81
  82   THREAD_OFF (timeout_thr);
  83
  84   FD_ZERO (&fds);
  85   snmp_select_info (&maxfd, &fds, &timeout, &block);
  86
  87   if (!block)
  88     timeout_thr = thread_add_timer_tv (agentx_tm, agentx_timeout, NULL, &timeout);
  89
  90   ln = listhead (events);
  91   thr = ln ? listgetdata (ln) : NULL;
  92   thr_fd = thr ? THREAD_FD (thr) : -1;
  93
  94   /* "two-pointer" / two-list simultaneous iteration
  95    * ln/thr/thr_fd point to the next existing event listener to hit while
  96    * fd counts to catch up */
  97   for (fd = 0; fd < maxfd; fd++)
  98     {
  99       /* caught up */
 100       if (thr_fd == fd)
 101         {
 102           struct listnode *nextln = listnextnode (ln);
 103           if (!FD_ISSET (fd, &fds))
 104             {
 105               thread_cancel (thr);
 106               list_delete_node (events, ln);
 107             }
 108           ln = nextln;
 109           thr = ln ? listgetdata (ln) : NULL;
 110           thr_fd = thr ? THREAD_FD (thr) : -1;
 111         }
 112       /* need listener, but haven't hit one where it would be */
 113       else if (FD_ISSET (fd, &fds))
 114         {
 115           struct listnode *newln;
 116           thr = thread_add_read (agentx_tm, agentx_read, NULL, fd);
 117           newln = listnode_add_before (events, ln, thr);
 118           thr->arg = newln;
 119         }
 120     }
 121
 122   /* leftover event listeners at this point have fd > maxfd, delete them */
 123   while (ln)
 124     {
 125       struct listnode *nextln = listnextnode (ln);
 126       thread_cancel (listgetdata (ln));
 127       list_delete_node (events, ln);
 128       ln = nextln;
 129     }
 130 }
 131
 132 /* AgentX node. */
 133 static struct cmd_node agentx_node =
 134 {
 135   SMUX_NODE,
 136   ""                            /* AgentX has no interface. */
 137 };
 138
 139 /* Logging NetSNMP messages */
 140 static int
 141 agentx_log_callback(int major, int minor,
 142                     void *serverarg, void *clientarg)
 143 {
 144   struct snmp_log_message *slm = (struct snmp_log_message *)serverarg;
 145   char *msg = XSTRDUP(MTYPE_TMP, slm->msg);
 146   if (msg) msg[strlen(msg)-1] = '\0';
 147   switch (slm->priority)
 148     {
 149     case LOG_EMERG:   zlog_err   ("snmp[emerg]: %s",   msg?msg:slm->msg); break;
 150     case LOG_ALERT:   zlog_err   ("snmp[alert]: %s",   msg?msg:slm->msg); break;
 151     case LOG_CRIT:    zlog_err   ("snmp[crit]: %s",    msg?msg:slm->msg); break;
 152     case LOG_ERR:     zlog_err   ("snmp[err]: %s",     msg?msg:slm->msg); break;
 153     case LOG_WARNING: zlog_warn  ("snmp[warning]: %s", msg?msg:slm->msg); break;
 154     case LOG_NOTICE:  zlog_notice("snmp[notice]: %s",  msg?msg:slm->msg); break;
 155     case LOG_INFO:    zlog_info  ("snmp[info]: %s",    msg?msg:slm->msg); break;
 156     case LOG_DEBUG:   zlog_debug ("snmp[debug]: %s",   msg?msg:slm->msg); break;
 157     }
 158   XFREE(MTYPE_TMP, msg);
 159   return SNMP_ERR_NOERROR;
 160 }
 161
 162 static int
 163 config_write_agentx (struct vty *vty)
 164 {
 165   if (agentx_enabled)
 166       vty_out (vty, "agentx%s", VTY_NEWLINE);
 167   return 0;
 168 }
 169
 170 DEFUN (agentx_enable,
 171        agentx_enable_cmd,
 172        "agentx",
 173        "SNMP AgentX protocol settings\n"
 174        "SNMP AgentX settings\n")
 175 {
 176   if (!agentx_enabled)
 177     {
 178       init_snmp("quagga");
 179       events = list_new();
 180       agentx_events_update ();
 181       agentx_enabled = 1;
 182       return CMD_SUCCESS;
 183     }
 184   vty_out (vty, "SNMP AgentX already enabled%s", VTY_NEWLINE);
 185   return CMD_WARNING;
 186 }
 187
 188 DEFUN (no_agentx,
 189        no_agentx_cmd,
 190        "no agentx",
 191        NO_STR
 192        "SNMP AgentX protocol settings\n"
 193        "SNMP AgentX settings\n")
 194 {
 195   if (!agentx_enabled) return CMD_SUCCESS;
 196   vty_out (vty, "SNMP AgentX support cannot be disabled once enabled%s", VTY_NEWLINE);
 197   return CMD_WARNING;
 198 }
 199
 200 void
 201 smux_init (struct thread_master *tm)
 202 {
 203   agentx_tm = tm;
 204
 205   netsnmp_enable_subagent ();
 206   snmp_disable_log ();
 207   snmp_enable_calllog ();
 208   snmp_register_callback (SNMP_CALLBACK_LIBRARY,
 209                           SNMP_CALLBACK_LOGGING,
 210                           agentx_log_callback,
 211                           NULL);
 212   init_agent ("quagga");
 213
 214   install_node (&agentx_node, config_write_agentx);
 215   install_element (CONFIG_NODE, &agentx_enable_cmd);
 216   install_element (CONFIG_NODE, &no_agentx_cmd);
 217 }
 218
 219 void
 220 smux_register_mib (const char *descr, struct variable *var,
 221                    size_t width, int num,
 222                    oid name[], size_t namelen)
 223 {
 224   register_mib (descr, var, width, num, name, namelen);
 225 }
 226
 227 int
 228 smux_trap (struct variable *vp, size_t vp_len,
 229            const oid *ename, size_t enamelen,
 230            const oid *name, size_t namelen,
 231            const oid *iname, size_t inamelen,
 232            const struct trap_object *trapobj, size_t trapobjlen,
 233            u_char sptrap)
 234 {
 235   oid objid_snmptrap[] = { 1, 3, 6, 1, 6, 3, 1, 1, 4, 1, 0 };
 236   size_t objid_snmptrap_len = sizeof objid_snmptrap / sizeof (oid);
 237   oid notification_oid[MAX_OID_LEN];
 238   size_t notification_oid_len;
 239   unsigned int i;
 240
 241   netsnmp_variable_list *notification_vars = NULL;
 242   if (!agentx_enabled) return 0;
 243
 244   /* snmpTrapOID */
 245   oid_copy (notification_oid, ename, enamelen);
 246   notification_oid[enamelen] = sptrap;
 247   notification_oid_len = enamelen + 1;
 248   snmp_varlist_add_variable (&notification_vars,
 249                              objid_snmptrap, objid_snmptrap_len,
 250                              ASN_OBJECT_ID,
 251                              (u_char *) notification_oid,
 252                              notification_oid_len * sizeof(oid));
 253
 254   /* Provided bindings */
 255   for (i = 0; i < trapobjlen; i++)
 256     {
 257       unsigned int j;
 258       oid oid[MAX_OID_LEN];
 259       size_t oid_len, onamelen;
 260       u_char *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         {
 268           /* Columnar object */
 269           onamelen = trapobj[i].namelen;
 270           oid_copy (oid, name, namelen);
 271           oid_copy (oid + namelen, trapobj[i].name, onamelen);
 272           oid_copy (oid + namelen + onamelen, iname, inamelen);
 273           oid_len = namelen + onamelen + inamelen;
 274         }
 275       else
 276         {
 277           /* Scalar object */
 278           onamelen = trapobj[i].namelen * (-1);
 279           oid_copy (oid, name, namelen);
 280           oid_copy (oid + namelen, trapobj[i].name, onamelen);
 281           oid[onamelen + namelen] = 0;
 282           oid_len = namelen + onamelen + 1;
 283         }
 284
 285       /* Locate the appropriate function and type in the MIB registry. */
 286       for (j = 0; j < vp_len; j++)
 287         {
 288           if (oid_compare (trapobj[i].name, onamelen, vp[j].name, vp[j].namelen) != 0)
 289             continue;
 290           /* We found the appropriate variable in the MIB 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, &wm);
 300           if (!val) break;
 301           snmp_varlist_add_variable (&notification_vars,
 302                                      oid, oid_len,
 303                                      vp[j].type,
 304                                      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 /* HAVE_SNMP */