agentx: handle SNMP traps

smux_trap() signature has been changed to provide appropriate level
information to send SNMPv2 notifications. This includes the addition
of the enterprise OID to use (from which is derived the SNMP trap OID)
and the MIB registry to locate the appropriate function for variable
bindings provided by the trap.

The SMUX implementation has been updated but ignore the provided
enterprise OID. Instead, it still uses the SMUX peer OID to keep
compatibility with previous versions of Quagga. The SMUX
implementation also ignores the provided MIB registry since it uses
smux_get() function to grab the appropriate values. This is not
possible with the AgentX implementation since there is no such
function provided by NetSNMP.

1 files changed, 81 insertions, 1 deletions

diff --git a/lib/agentx.c b/lib/agentx.c
index 2358581f..be6b4320 100644
--- a/lib/agentx.c
+++ b/lib/agentx.c
@@ -122,11 +122,91 @@ smux_register_mib (const char *descr, struct variable *var,
 }
 
 int
-smux_trap (const oid *name, size_t namelen,
+smux_trap (struct variable *vp, size_t vp_len,
+	   const oid *ename, size_t enamelen,
+	   const oid *name, size_t namelen,
 	   const oid *iname, size_t inamelen,
 	   const struct trap_object *trapobj, size_t trapobjlen,
 	   u_char sptrap)
 {
+  oid objid_snmptrap[] = { 1, 3, 6, 1, 6, 3, 1, 1, 4, 1, 0 };
+  size_t objid_snmptrap_len = sizeof objid_snmptrap / sizeof (oid);
+  oid notification_oid[MAX_OID_LEN];
+  size_t notification_oid_len;
+  unsigned int i;
+
+  netsnmp_variable_list *notification_vars = NULL;
+  if (!agentx_enabled) return 0;
+
+  /* snmpTrapOID */
+  oid_copy (notification_oid, ename, enamelen);
+  notification_oid[enamelen] = sptrap;
+  notification_oid_len = enamelen + 1;
+  snmp_varlist_add_variable (&notification_vars,
+			     objid_snmptrap, objid_snmptrap_len,
+			     ASN_OBJECT_ID,
+			     (u_char *) notification_oid,
+			     notification_oid_len * sizeof(oid));
+
+  /* Provided bindings */
+  for (i = 0; i < trapobjlen; i++)
+    {
+      unsigned int j;
+      oid oid[MAX_OID_LEN];
+      size_t oid_len, onamelen;
+      u_char *val;
+      size_t val_len;
+      WriteMethod *wm = NULL;
+      struct variable cvp;
+
+      /* Make OID. */
+      if (trapobj[i].namelen > 0)
+        {
+	  /* Columnar object */
+	  onamelen = trapobj[i].namelen;
+	  oid_copy (oid, name, namelen);
+	  oid_copy (oid + namelen, trapobj[i].name, onamelen);
+	  oid_copy (oid + namelen + onamelen, iname, inamelen);
+	  oid_len = namelen + onamelen + inamelen;
+        }
+      else
+        {
+	  /* Scalar object */
+	  onamelen = trapobj[i].namelen * (-1);
+	  oid_copy (oid, name, namelen);
+	  oid_copy (oid + namelen, trapobj[i].name, onamelen);
+	  oid[onamelen + namelen] = 0;
+	  oid_len = namelen + onamelen + 1;
+        }
+
+      /* Locate the appropriate function and type in the MIB registry. */
+      for (j = 0; j < vp_len; j++)
+	{
+	  if (oid_compare (trapobj[i].name, onamelen, vp[j].name, vp[j].namelen) != 0)
+	    continue;
+	  /* We found the appropriate variable in the MIB registry. */
+	  oid_copy(cvp.name, name, namelen);
+	  oid_copy(cvp.name + namelen, vp[j].name, vp[j].namelen);
+	  cvp.namelen = namelen + vp[j].namelen;
+	  cvp.type = vp[j].type;
+	  cvp.magic = vp[j].magic;
+	  cvp.acl = vp[j].acl;
+	  cvp.findVar = vp[j].findVar;
+	  /* Grab the result. */
+	  val = cvp.findVar (&cvp, oid, &oid_len, 1, &val_len, &wm);
+	  if (!val) break;
+	  snmp_varlist_add_variable (&notification_vars,
+				     oid, oid_len,
+				     vp[j].type,
+				     val,
+				     val_len);
+	  break;
+	}
+    }
+
+
+  send_v2trap (notification_vars);
+  snmp_free_varbind (notification_vars);
   return 1;
 }