snmp.xs

ucd-snmp源代码

   else
    {
     count = perl_call_sv(sv, flags);
    }
 }
 LEAVE;
 return count;
}

/* Bulkwalk support routines */

/* Add a context pointer to the list of valid pointers.  Place it in the first
** NULL slot in the array.
*/
static int
_context_add(walk_context *context)
{
    int i, j, new_sz;

    if ((i = _context_okay(context)) != 0)	/* Already exists?  Okay. */
	return i;

    /* Initialize the array if necessary. */
    if (_valid_contexts == NULL) {

	/* Create the _valid_contexts structure. */
	Newz(0, _valid_contexts, 1, struct valid_contexts);
	assert(_valid_contexts != NULL);

	/* Populate the original valid contexts array. */
	Newz(0, _valid_contexts->valid, 4, walk_context *);
	assert(_valid_contexts->valid != NULL);

	/* Computer number of slots in the array. */
	_valid_contexts->sz_valid = sizeof(*_valid_contexts->valid) /
							sizeof(walk_context *);

	for (i = 0; i < _valid_contexts->sz_valid; i++)
	    _valid_contexts->valid[i] = NULL;

	DBPRT(3, (DBOUT "Created valid_context array 0x%p (%d slots)\n",
			    _valid_contexts->valid, _valid_contexts->sz_valid));
    }

    /* Search through the list, looking for NULL's -- unused slots. */
    for (i = 0; i < _valid_contexts->sz_valid; i++)
	if (_valid_contexts->valid[i] == NULL)
	    break;

    /* Did we walk off the end of the list?  Need to grow the list.  Double
    ** it for now.
    */
    if (i == _valid_contexts->sz_valid) {
	new_sz = _valid_contexts->sz_valid * 2;

	Renew(_valid_contexts->valid, new_sz, walk_context *);
	assert(_valid_contexts->valid != NULL);

	DBPRT(3, (DBOUT "Resized valid_context array 0x%p from %d to %d slots\n",
		    _valid_contexts->valid, _valid_contexts->sz_valid, new_sz));

	_valid_contexts->sz_valid = new_sz;

	/* Initialize the new half of the resized array. */
	for (j = i; j < new_sz; j++)
	    _valid_contexts->valid[j] = NULL;
    }

    /* Store the context pointer in the array and return 0 (success). */
    _valid_contexts->valid[i] = context;
    DBPRT(3,( "Add context 0x%p to valid context list\n", context));
    return 0;
}

/* Remove a context pointer from the valid list.  Replace the pointer with
** NULL in the valid pointer list.
*/
static int
_context_del(walk_context *context)
{
    int i;

    if (_valid_contexts == NULL)	/* Make sure it was initialized. */
	return 1;

    for (i = 0; i < _valid_contexts->sz_valid; i++) {
	if (_valid_contexts->valid[i] == context) {
	    DBPRT(3,( "Remove context 0x%p from valid context list\n", context));
	    _valid_contexts->valid[i] = NULL;	/* Remove it from the list.  */
	    return 0;				/* Return successful status. */
	}
    }
    return 1;
}

/* Check if a specific context pointer is in the valid list.  Return true (1)
** if the context is still in the valid list, or 0 if not (or context is NULL).
*/
static int
_context_okay(walk_context *context)
{
    int i;

    if (_valid_contexts == NULL)	/* Make sure it was initialized. */
	return 0;

    if (context == NULL)		/* Asked about a NULL context? Fail. */
	return 0;

    for (i = 0; i < _valid_contexts->sz_valid; i++)
	if (_valid_contexts->valid[i] == context)
	    return 1;			/* Found it! */

    return 0;				/* No match -- return failure. */
}

/* Check if the walk is completed, based upon the context.  Also set the
** ignore flag on any completed variables -- this prevents them from being
** being sent in later packets.
*/
static int
_bulkwalk_done(walk_context *context)
{
   int is_done = 1;
   int i;
   bulktbl *bt_entry;		/* bulktbl requested OID entry */

   /* Don't consider walk done until at least one packet has been exchanged. */
   if (context->pkts_exch == 0)
      return 0;

   /* Fix up any requests that have completed.  If the complete flag is set,
   ** or it is a non-repeater OID, set the ignore flag so that it will not
   ** be considered further.  Assume we are done with the walk, and note
   ** otherwise if we aren't.  Return 1 if all requests are complete, or 0
   ** if there's more to do.
   */
   for (i = 0; i < context->nreq_oids; i ++) {
      bt_entry = &context->req_oids[i];

      if (bt_entry->complete || bt_entry->norepeat) {

 	/* This request is complete.  Remove it from list of
 	** walks still in progress.
 	*/
 	DBPRT(1, (DBOUT "Ignoring %s request oid %s\n",
 	      bt_entry->norepeat? "nonrepeater" : "completed",
 	      sprint_objid(_debugx, bt_entry->req_oid,
 				    bt_entry->req_len)));

 	/* Ignore this OID in any further packets. */
 	bt_entry->ignore = 1;
      }

      /* If any OID is not being ignored, the walk is not done.  Must loop
      ** through all requests to do the fixup -- no early return possible.
      */
      if (!bt_entry->ignore)
 	 is_done = 0;
   }

   return is_done;		/* Did the walk complete? */
}

/* Callback registered with SNMP.  Return 1 from this callback to cause the
** current request to be deleted from the retransmit queue.
*/
static int
_bulkwalk_async_cb(int		op,
		  SnmpSession	*ss,
		  int 		reqid,
		  struct snmp_pdu *pdu,
		  void		*context_ptr)
{
   walk_context *context;
   int	done = 0;
   int	npushed;
   SV **err_str_svp;
   SV **err_num_svp;

   /* Handle callback request for asynchronous bulkwalk.  If the bulkwalk has
   ** not completed, and has not timed out, send the next request packet in
   ** the walk.
   **
   ** Return 0 to indicate success (caller ignores return value).
   */

   DBPRT(2, (DBOUT "bulkwalk_async_cb(op %d, reqid 0x%08X, context 0x%p)\n",
							op, reqid, context_ptr));

   context = (walk_context *)context_ptr;

   /* Make certain this is a valid context pointer.  This pdu may
   ** have been retransmitted after the bulkwalk was completed
   ** (and the context was destroyed).  If so, just return.
   */
   if (!_context_okay(context)) {
      DBPRT(2,( "Ignoring PDU for dead context 0x%p...\n", context));
      return 1;
   }

   /* Is this a retransmission of a request we've already seen or some
   ** unexpected request id?  If so, just ignore it.
   */
   if (reqid != context->exp_reqid) {
       DBPRT(2,
             ("Got reqid 0x%08X, expected reqid 0x%08X.  Ignoring...\n", reqid,
              context->exp_reqid));
      return 1;
   }
   /* Ignore any future packets for this reqid. */
   context->exp_reqid = -1;

   err_str_svp = hv_fetch((HV*)SvRV(context->sess_ref), "ErrorStr", 8, 1);
   err_num_svp = hv_fetch((HV*)SvRV(context->sess_ref), "ErrorNum", 8, 1);

   switch (op) {
      case RECEIVED_MESSAGE:
      {
	 DBPRT(1,( "Received message for reqid 0x%08X ...\n", reqid));

	 switch (pdu->command)
	 {
	    case SNMP_MSG_RESPONSE:
	    {
	       DBPRT(2, (DBOUT "Calling bulkwalk_recv_pdu(context 0x%p, pdu 0x%p)\n",
							   context_ptr, pdu));

	       /* Handle the response PDU.  If an error occurs or there were
	       ** no variables in the response, consider the walk done.  If
	       ** the response was okay, check if we have any more to do after
	       ** this response.
	       */
	       if (_bulkwalk_recv_pdu(context, pdu) <= 0)
		  done = 1;
	       else
		  done = _bulkwalk_done(context); /* Also set req ignore flags */
	       break;
	    }
	    default:
	    {
	       DBPRT(1,( "unexpected pdu->command %d\n", pdu->command));
	       done = 1;   /* "This can't happen!", so bail out when it does. */
	       break;
	    }
	 }

	 break;
      }

      case TIMED_OUT:
      {
	 DBPRT(1,( "\n*** Timeout for reqid 0x%08X\n\n", reqid));

         sv_setpv(*err_str_svp, (char*)snmp_api_errstring(SNMPERR_TIMEOUT));
         sv_setiv(*err_num_svp, SNMPERR_TIMEOUT);

	 /* Timeout means something bad has happened.  Return a not-okay
	 ** result to the async callback.
	 */
	 npushed = _bulkwalk_finish(context, 0 /* NOT OKAY */);
	 return 1;
      }

      default:
      {
	 DBPRT(1,( "unexpected callback op %d\n", op));
         sv_setpv(*err_str_svp, (char*)snmp_api_errstring(SNMPERR_GENERR));
         sv_setiv(*err_num_svp, SNMPERR_GENERR);
	 npushed = _bulkwalk_finish(context, 0 /* NOT OKAY */);
	 return 1;
      }
   }

   /* We have either timed out, or received and parsed in a response.  Now,
   ** if we have more variables to test, call bulkwalk_send_pdu() to enqueue
   ** another async packet, and return.
   **
   ** If, however, the bulkwalk has completed (or an error has occurred that
   ** cuts the walk short), call bulkwalk_finish() to push the results onto
   ** the Perl call stack.  Then explicitly call the Perl callback that was
   ** passed in by the user oh-so-long-ago.
   */
   if (!done) {
      DBPRT(1,( "bulkwalk not complete -- send next pdu from callback\n"));

      if (_bulkwalk_send_pdu(context) != NULL)
	 return 1;

      DBPRT(1,( "send_pdu() failed!\n"));
      /* Fall through and return what we have so far. */
   }

   /* Call the perl callback with the return values and we're done. */
   npushed = _bulkwalk_finish(context, 1 /* OKAY */);

   return 1;
}

static struct snmp_pdu *
_bulkwalk_send_pdu(walk_context *context)
{
   struct snmp_pdu *pdu = NULL;
   struct snmp_pdu *response = NULL;
   struct bulktbl  *bt_entry;
   int	nvars = 0;
   int	reqid;
   int	status;
   int	i;

   /* Send a pdu requesting any remaining variables in the context.
   **
   ** In synchronous mode, returns a pointer to the response packet.
   **
   ** In asynchronous mode, it returns the request ID, cast to a struct snmp *,
   **   not a valid SNMP response packet.  The async code should not be trying
   **   to get variables out of this "response".
   **
   ** In either case, return a NULL pointer on error or failure.
   */

   SV **sess_ptr_sv = hv_fetch((HV*)SvRV(context->sess_ref), "SessPtr", 7, 1);
   struct snmp_session *ss = (SnmpSession *)SvIV((SV*)SvRV(*sess_ptr_sv));
   SV **err_str_svp = hv_fetch((HV*)SvRV(context->sess_ref), "ErrorStr", 8, 1);
   SV **err_num_svp = hv_fetch((HV*)SvRV(context->sess_ref), "ErrorNum", 8, 1);
   SV **err_ind_svp = hv_fetch((HV*)SvRV(context->sess_ref), "ErrorInd", 8, 1);

   /* Create a new PDU and send the remaining set of requests to the agent. */
   pdu = snmp_pdu_create(SNMP_MSG_GETBULK);
   if (pdu == NULL) {
      sv_setpv(*err_str_svp, "snmp_pdu_create(GETBULK) failed: ");
      sv_catpv(*err_str_svp, strerror(errno));
      sv_setiv(*err_num_svp, SNMPERR_MALLOC);
      goto err;
   }

   /* Request non-repeater variables only in the first packet exchange. */
   pdu->errstat  = (context->pkts_exch == 0) ? context->non_reps : 0;
   pdu->errindex = context->max_reps;

   for (i = 0; i < context->nreq_oids; i++) {
      bt_entry = &context->req_oids[i];
      if (bt_entry->ignore)
	 continue;

      assert(bt_entry->complete == 0);

      if (!snmp_add_null_var(pdu, bt_entry->last_oid, bt_entry->last_len)) {
	 sv_setpv(*err_str_svp, "snmp_add_null_var() failed");
	 sv_setiv(*err_num_svp, SNMPERR_GENERR);
	 sv_setiv(*err_ind_svp, i);
	 goto err;
      }

      nvars ++;

      DBPRT(1, (DBOUT "   Add %srepeater %s\n", bt_entry->norepeat ? "non" : "",
	         sprint_objid(_debugx, bt_entry->last_oid, bt_entry->last_len)));
   }

   /* Make sure variables are actually being requested in the packet. */
   assert (nvars != 0);

   context->pkts_exch ++;

   DBPRT(1, (DBOUT "Sending %ssynchronous request %d...\n",
		     SvTRUE(context->perl_cb) ? "a" : "", context->pkts_exch));

   /* We handle the asynchronous and synchronous requests differently here.
   ** For async, we simply enqueue the packet with a callback to handle the
   ** returned response, then return.  Note that this we call the bulkwalk
   ** callback, and hand it the walk_context, not the Perl callback.  The
   ** snmp_async_send() function returns the reqid on success, 0 on failure.
   */
   if (SvTRUE(context->perl_cb)) {
      reqid = snmp_async_send(ss, pdu, _bulkwalk_async_cb, (void *)context);

      DBPRT(2,( "bulkwalk_send_pdu(): snmp_async_send => 0x%08X\n", reqid));

      if (reqid == 0) {
	 sv_setpv(*err_str_svp, (char*)snmp_api_errstring(ss->s_snmp_errno));
	 sv_setiv(*err_num_svp, ss->s_snmp_errno);
	 goto err;
      }

      /* Make a note of the request we expect to be answered. */
      context->exp_reqid = reqid;

      /* Callbacks take care of the rest.  Let the caller know how many vars
      ** we sent in this request.  Note that this is not a valid SNMP PDU,
      ** but that's because a response has not yet been received.
      */
      return (struct snmp_pdu *)reqid;
   }

   /* This code is for synchronous mode support.
   **
   ** Send the PDU and block awaiting the response.  Return the response
   ** packet back to the caller.  Note that snmp_sess_read() frees the pdu.
   */
   status = __send_sync_pdu(ss, pdu, &response, NO_RETRY_NOSUCH,
				    *err_str_svp, *err_num_svp, *err_ind_svp);

   pdu = NULL;

   /* Check for a failed request.  __send_sync_pdu() will set the appropriate
   ** values in the error string and number SV's.
   */
   if (status != STAT_SUCCESS) {
      DBPRT(1,( "__send_sync_pdu() -> %d\n",(int)status));
      goto err;
   }

   DBPRT(1, (DBOUT "%d packets exchanged, response 0x%p\n", context->pkts_exch,
								    response));
   return response;


   err:
   if (pdu)
      snmp_free_pdu(pdu);
   return NULL;
}

/* Handle an incoming GETBULK response PDU.  This function just pulls the
** variables off of the PDU and builds up the arrays of returned values
** that are stored in the context.
**
** Returns the number of variables found in this packet, or -1 on error.
** Note that the caller is expected to free the pdu.
*/
static int
_bulkwalk_recv_pdu(walk_context *context, struct snmp_pdu *pdu)
{
   struct variable_list *vars;
   struct tree	*tp;
   char		type_str[MAX_TYPE_NAME_LEN];
   char		str_buf[STR_BUF_SIZE];