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 #ifdef 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 #include "version.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
  45 agentx_timeout(struct thread *t)
  46 {
  47   timeout_thr = NULL;
  48
  49   snmp_timeout ();
  50   run_alarms ();
  51   netsnmp_check_outstanding_agent_requests ();
  52   agentx_events_update ();
  53   return 0;
  54 }
  55
  56 static int
  57 agentx_read(struct thread *t)
  58 {
  59   fd_set fds;
  60   struct listnode *ln = THREAD_ARG (t);
  61   list_delete_node (events, ln);
  62
  63   FD_ZERO (&fds);
  64   FD_SET (THREAD_FD (t), &fds);
  65   snmp_read (&fds);
  66
  67   netsnmp_check_outstanding_agent_requests ();
  68   agentx_events_update ();
  69   return 0;
  70 }
  71
  72 static void
  73 agentx_events_update(void)
  74 {
  75   int maxfd = 0;
  76   int block = 1;
  77   struct timeval timeout = { .tv_sec = 0, .tv_usec = 0 };
  78   fd_set fds;
  79   struct listnode *ln;
  80   struct thread *thr;
  81   int fd, thr_fd;
  82
  83   THREAD_OFF (timeout_thr);
  84
  85   FD_ZERO (&fds);
  86   snmp_select_info (&maxfd, &fds, &timeout, &block);
  87
  88   if (!block)
  89     timeout_thr = thread_add_timer_tv (agentx_tm, agentx_timeout, NULL, &timeout);
  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     {
 100       /* caught up */
 101       if (thr_fd == fd)
 102         {
 103           struct listnode *nextln = listnextnode (ln);
 104           if (!FD_ISSET (fd, &fds))
 105             {
 106               thread_cancel (thr);
 107               list_delete_node (events, ln);
 108             }
 109           ln = nextln;
 110           thr = ln ? listgetdata (ln) : NULL;
 111           thr_fd = thr ? THREAD_FD (thr) : -1;
 112         }
 113       /* need listener, but haven't hit one where it would be */
 114       else if (FD_ISSET (fd, &fds))
 115         {
 116           struct listnode *newln;
 117           thr = thread_add_read (agentx_tm, agentx_read, NULL, fd);
 118           newln = listnode_add_before (events, ln, thr);
 119           thr->arg = newln;
 120         }
 121     }
 122
 123   /* leftover event listeners at this point have fd > maxfd, delete them */
 124   while (ln)
 125     {
 126       struct listnode *nextln = listnextnode (ln);
 127       thread_cancel (listgetdata (ln));
 128       list_delete_node (events, ln);
 129       ln = nextln;
 130     }
 131 }
 132
 133 /* AgentX node. */
 134 static struct cmd_node agentx_node =
 135 {
 136   SMUX_NODE,
 137   ""                            /* AgentX has no interface. */
 138 };
 139
 140 /* Logging NetSNMP messages */
 141 static int
 142 agentx_log_callback(int major, int minor,
 143                     void *serverarg, void *clientarg)
 144 {
 145   struct snmp_log_message *slm = (struct snmp_log_message *)serverarg;
 146   char *msg = XSTRDUP(MTYPE_TMP, slm->msg);
 147   if (msg) msg[strlen(msg)-1] = '\0';
 148   switch (slm->priority)
 149     {
 150     case LOG_EMERG:   zlog_err   ("snmp[emerg]: %s",   msg?msg:slm->msg); break;
 151     case LOG_ALERT:   zlog_err   ("snmp[alert]: %s",   msg?msg:slm->msg); break;
 152     case LOG_CRIT:    zlog_err   ("snmp[crit]: %s",    msg?msg:slm->msg); break;
 153     case LOG_ERR:     zlog_err   ("snmp[err]: %s",     msg?msg:slm->msg); break;
 154     case LOG_WARNING: zlog_warn  ("snmp[warning]: %s", msg?msg:slm->msg); break;
 155     case LOG_NOTICE:  zlog_notice("snmp[notice]: %s",  msg?msg:slm->msg); break;
 156     case LOG_INFO:    zlog_info  ("snmp[info]: %s",    msg?msg:slm->msg); break;
 157     case LOG_DEBUG:   zlog_debug ("snmp[debug]: %s",   msg?msg:slm->msg); break;
 158     }
 159   XFREE(MTYPE_TMP, msg);
 160   return SNMP_ERR_NOERROR;
 161 }
 162
 163 static int
 164 config_write_agentx (struct vty *vty)
 165 {
 166   if (agentx_enabled)
 167       vty_out (vty, "agentx%s", VTY_NEWLINE);
 168   return 0;
 169 }
 170
 171 DEFUN (agentx_enable,
 172        agentx_enable_cmd,
 173        "agentx",
 174        "SNMP AgentX protocol settings\n"
 175        "SNMP AgentX settings\n")
 176 {
 177   if (!agentx_enabled)
 178     {
 179       init_snmp(FRR_SMUX_NAME);
 180       events = list_new();
 181       agentx_events_update ();
 182       agentx_enabled = 1;
 183       return CMD_SUCCESS;
 184     }
 185   vty_out (vty, "SNMP AgentX already enabled%s", VTY_NEWLINE);
 186   return CMD_WARNING;
 187 }
 188
 189 DEFUN (no_agentx,
 190        no_agentx_cmd,
 191        "no agentx",
 192        NO_STR
 193        "SNMP AgentX protocol settings\n"
 194        "SNMP AgentX settings\n")
 195 {
 196   if (!agentx_enabled) return CMD_SUCCESS;
 197   vty_out (vty, "SNMP AgentX support cannot be disabled once enabled%s", VTY_NEWLINE);
 198   return CMD_WARNING;
 199 }
 200
 201 void
 202 smux_init (struct thread_master *tm)
 203 {
 204   agentx_tm = tm;
 205
 206   netsnmp_enable_subagent ();
 207   snmp_disable_log ();
 208   snmp_enable_calllog ();
 209   snmp_register_callback (SNMP_CALLBACK_LIBRARY,
 210                           SNMP_CALLBACK_LOGGING,
 211                           agentx_log_callback,
 212                           NULL);
 213   init_agent (FRR_SMUX_NAME);
 214
 215   install_node (&agentx_node, config_write_agentx);
 216   install_element (CONFIG_NODE, &agentx_enable_cmd);
 217   install_element (CONFIG_NODE, &no_agentx_cmd);
 218 }
 219
 220 void
 221 smux_register_mib (const char *descr, struct variable *var,
 222                    size_t width, int num,
 223                    oid name[], size_t namelen)
 224 {
 225   register_mib (descr, var, width, num, name, namelen);
 226 }
 227
 228 int
 229 smux_trap (struct variable *vp, size_t vp_len,
 230            const oid *ename, size_t enamelen,
 231            const oid *name, size_t namelen,
 232            const oid *iname, size_t inamelen,
 233            const struct trap_object *trapobj, size_t trapobjlen,
 234            u_char 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) return 0;
 244
 245   /* snmpTrapOID */
 246   oid_copy (notification_oid, ename, enamelen);
 247   notification_oid[enamelen] = sptrap;
 248   notification_oid_len = enamelen + 1;
 249   snmp_varlist_add_variable (&notification_vars,
 250                              objid_snmptrap, objid_snmptrap_len,
 251                              ASN_OBJECT_ID,
 252                              (u_char *) notification_oid,
 253                              notification_oid_len * sizeof(oid));
 254
 255   /* Provided bindings */
 256   for (i = 0; i < trapobjlen; i++)
 257     {
 258       unsigned int j;
 259       oid oid[MAX_OID_LEN];
 260       size_t oid_len, onamelen;
 261       u_char *val;
 262       size_t val_len;
 263       WriteMethod *wm = NULL;
 264       struct variable cvp;
 265
 266       /* Make OID. */
 267       if (trapobj[i].namelen > 0)
 268         {
 269           /* Columnar object */
 270           onamelen = trapobj[i].namelen;
 271           oid_copy (oid, name, namelen);
 272           oid_copy (oid + namelen, trapobj[i].name, onamelen);
 273           oid_copy (oid + namelen + onamelen, iname, inamelen);
 274           oid_len = namelen + onamelen + inamelen;
 275         }
 276       else
 277         {
 278           /* Scalar object */
 279           onamelen = trapobj[i].namelen * (-1);
 280           oid_copy (oid, name, namelen);
 281           oid_copy (oid + namelen, trapobj[i].name, onamelen);
 282           oid[onamelen + namelen] = 0;
 283           oid_len = namelen + onamelen + 1;
 284         }
 285
 286       /* Locate the appropriate function and type in the MIB registry. */
 287       for (j = 0; j < vp_len; j++)
 288         {
 289           if (oid_compare (trapobj[i].name, onamelen, vp[j].name, vp[j].namelen) != 0)
 290             continue;
 291           /* We found the appropriate variable in the MIB registry. */
 292           oid_copy(cvp.name, name, namelen);
 293           oid_copy(cvp.name + namelen, vp[j].name, vp[j].namelen);
 294           cvp.namelen = namelen + vp[j].namelen;
 295           cvp.type = vp[j].type;
 296           cvp.magic = vp[j].magic;
 297           cvp.acl = vp[j].acl;
 298           cvp.findVar = vp[j].findVar;
 299           /* Grab the result. */
 300           val = cvp.findVar (&cvp, oid, &oid_len, 1, &val_len, &wm);
 301           if (!val) break;
 302           snmp_varlist_add_variable (&notification_vars,
 303                                      oid, oid_len,
 304                                      vp[j].type,
 305                                      val,
 306                                      val_len);
 307           break;
 308         }
 309     }
 310
 311
 312   send_v2trap (notification_vars);
 313   snmp_free_varbind (notification_vars);
 314   agentx_events_update ();
 315   return 1;
 316 }
 317
 318 #endif /* SNMP_AGENTX */