snmp.xs

开发snmp的开发包有两个开放的SNMP开发库

	       else
		  done = _bulkwalk_done(context); /* Also set req ignore flags */
	       break;
	    }
	    default:
	    {
	       DBPRT(1,(DBOUT "unexpected pdu->command %d\n", pdu->command));
	       done = 1;   /* "This can't happen!", so bail out when it does. */
	       break;
	    }
	 }

	 break;
      }

      case NETSNMP_CALLBACK_OP_TIMED_OUT:
      {
	 DBPRT(1,(DBOUT "\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,(DBOUT "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,(DBOUT "bulkwalk not complete -- send next pdu from callback\n"));

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

      DBPRT(1,(DBOUT "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 netsnmp_pdu *
_bulkwalk_send_pdu(walk_context *context)
{
   netsnmp_pdu *pdu = NULL;
   netsnmp_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);
   netsnmp_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" : "", 
		__snprint_oid(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,(DBOUT "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 (netsnmp_pdu *)(intptr_t)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,(DBOUT "__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, netsnmp_pdu *pdu)
{
   netsnmp_variable_list *vars;
   struct tree	*tp;
   char		type_str[MAX_TYPE_NAME_LEN];
   char	        str_buf[STR_BUF_SIZE], *str_bufp = str_buf;
   size_t str_buf_len = sizeof(str_buf);
   size_t out_len = 0;
   int buf_over = 0;
   char		*label;
   char		*iid;
   bulktbl	*expect = NULL;
   int		old_numeric;
   int		old_printfull;
   int		old_format;
   int		getlabel_flag;
   int		type;
   int		pix;
   int		len;
   int		i;
   AV		*varbind;
   SV		*rv;
   DBDCL(SV**sess_ptr_sv=hv_fetch((HV*)SvRV(context->sess_ref),"SessPtr",7,1);)
   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);
   int check =  SvIV(*hv_fetch((HV*)SvRV(context->sess_ref), "NonIncreasing",13,1));

   DBPRT(3, (DBOUT "bulkwalk: sess_ref = 0x%p, sess_ptr_sv = 0x%p\n",
             context->sess_ref, sess_ptr_sv));

   /* Set up for numeric OID's, if necessary.  Save the old values
   ** so that they can be restored when we finish -- these are
   ** library-wide globals, and have to be set/restored for each
   ** session.
   */
   old_numeric   = netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_PRINT_NUMERIC_OIDS);
   old_printfull = netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_PRINT_FULL_OID);
   old_format = netsnmp_ds_get_int(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_OID_OUTPUT_FORMAT);
   if (context->getlabel_f & USE_NUMERIC_OIDS) {
      DBPRT(2,(DBOUT "Using numeric oid's\n"));
      netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_PRINT_NUMERIC_OIDS, 1);
      netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_PRINT_FULL_OID, 1);
      netsnmp_ds_set_int(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_OID_OUTPUT_FORMAT, NETSNMP_OID_OUTPUT_NUMERIC);
   }

   /* Parse through the list of variables returned, adding each return to
   ** the appropriate array (as a VarBind).  Also keep track of which
   ** repeated OID we're expecting to see, and check if that tree walk has
   ** been completed (i.e. we've walked past the root of our request).  If
   ** so, mark the request complete so that we don't send it again in any
   ** subsequent request packets.
   */
   if (context->pkts_exch == 1)
      context->reqbase = context->req_oids;	/* Request with non-repeaters */
   else
      context->reqbase = context->repbase;	/* Request only repeater vars */

   /* Note the first variable we expect to see.  Should be reqbase. */
   expect = context->reqbase;

   for (vars = pdu->variables, pix = 0;
	vars != NULL;
	vars = vars->next_variable, pix ++)
   {

      /* If no outstanding requests remain, we're done.  This works, but it
      ** causes the reported total variable count to be wrong (since the
      ** remaining vars on the last packet are not counted).  In practice
      ** this is probably worth the win, but for debugging it's not.
      */
      if (context->req_remain == 0) {
	 DBPRT(2,(DBOUT "No outstanding requests remain.  Terminating processing.\n"));
	 while (vars) {
	    pix ++;
	    vars = vars->next_variable;
	 }
	 break;
      }

      /* Determine which OID we expect to see next.  We assert that the OID's
      ** must be returned in the expected order.  The first nreq_oids returns
      ** should match the req_oids array, after that, we must cycle through
      ** the repeaters in order.  Non-repeaters are not included in later
      ** packets, so cannot have the "ignore" flag set.
      */

      if (context->oid_saved < context->non_reps) {
	 assert(context->pkts_exch == 1);

	 expect = context->reqbase ++;
	 assert(expect->norepeat);

      } else {
	 /* Must be a repeater.  Look for the first one that is not being
	 ** ignored.  Make sure we don't loop around to where we started.
	 ** If we get here but everything is being ignored, there's a problem.
	 **
	 ** Note that we *do* accept completed but not ignored OID's -- these
	 ** are OID's for trees that have been completed sometime in this
	 ** response, but must be looked at to maintain ordering.
	 */
	 /* In previous version we started from 1st repeater any time when
	 ** pix == 0. But if 1st repeater is ignored we can get wrong results,
	 ** because it was not included in 2nd and later request. So we set
	 ** expect to repbase-1 and then search for 1st non-ignored repeater.
	 ** repbase-1 is nessessary because we're starting search in loop below
	 ** from ++expect and it will be exactly repbase on 1st search pass.
	 */
	 if (pix == 0)
	    expect = context->repbase - 1;

	 /* Find the repeater OID we expect to see.  Ignore any
	 ** OID's marked 'ignore' -- these have been completed
	 ** and were not requested in this iteration.
	 */
	 for (i = 0; i < context->repeaters; i++) {

	    /* Loop around to first repeater if we hit the end. */
	    if (++ expect == &context->req_oids[context->nreq_oids])
	       expect = context->reqbase = context->repbase;

	    /* Stop if this OID is not being ignored. */
	    if (!expect->ignore)
	       break;
	 }
      }

      DBPRT(2, (DBOUT "Var %03d request %s\n", pix,
		__snprint_oid(expect->req_oid, expect->req_len)));

      /* Did we receive an error condition for this variable?
      ** If it's a repeated variable, mark it as complete and
      ** fall through to the block below.
      */
      if ((vars->type == SNMP_ENDOFMIBVIEW) ||
	  (vars->type == SNMP_NOSUCHOBJECT) ||
	  (vars->type == SNMP_NOSUCHINSTANCE))
      {
	 DBPRT(2,(DBOUT "error type %d\n", (int)vars->type));

	 /* ENDOFMIBVIEW should be okay for a repeater - just walked off the
	 ** end of the tree.  Mark the request as complete, and go on to the
	 ** next one.
	 */
	 if ((context->oid_saved >= context->non_reps) &&
	     (vars->type == SNMP_ENDOFMIBVIEW))
	 {
	    expect->complete = 1;
	    DBPRT(2, (DBOUT "Ran out of tree for oid %s\n",
		      __snprint_oid(vars->name,vars->name_length)));

	    context->req_remain --;

	    /* Go on to the next variable. */
	    continue;

	 }
	 sv_setpv(*err_str_svp,
			      (char*)snmp_api_errstring(SNMPERR_UNKNOWN_OBJID));
	 sv_setiv(*err_num_svp, SNMPERR_UNKNOWN_OBJID);
	 sv_setiv(*err_ind_svp, pix);
	 goto err;
      }

      /* If this is not the first packet, skip any duplicated OID values, if
      ** present.  These should be the seed values copied from the last OID's
      ** of the previous packet.  In practice we don't see this, but it is
      ** easy enough to do, and will avoid confusion for the caller from mis-
      ** behaving agents (badly misbehaving... ;^).
      */
      if ((context->pkts_exch > 1) && (pix < context->repeaters)) {
	 if (__oid_cmp(vars->name, vars->name_length,
				   context->reqbase[pix].last_oid,
				   context->reqbase[pix].last_len) <= 0)
	 {
            if (check) 
            {
	      DBPRT(2, (DBOUT "Error: OID not increasing: %s\n",
			__snprint_oid(vars->name,vars->name_length)));
               sv_setpv(*err_str_svp, (char*)snmp_api_errstring(SNMPERR_OID_NONINCREASING));
               sv_setiv(*err_num_svp, SNMPERR_OID_NONINCREASING);
               sv_setiv(*err_ind_svp, pix);
               goto err;
            }
              
	    DBPRT(2, (DBOUT "Ignoring repeat oid: %s\n",
			__snprint_oid(vars->name,vars->name_length)));

	    continue;
	 }
      }

      context->oid_total ++;	/* Count each variable received. */

      /* If this is a non-repeater, handle it.  Otherwise, if it is a
      ** repeater, has the walk wandered off of the requested tree?  If so,
      ** this request is complete, so mark it as such.  Ignore any other
      ** variables in a completed request.  In order to maintain the correct
      ** ordering of which variables we expect to see in this packet, we must
      ** not set the ignore flags immediately.  It is done in bulkwalk_done().
      ** XXX Can we use 'expect' instead of 'context->req_oids[pix]'?
      */
      if (context->oid_saved < context->non_reps) {
	DBPRT(2, (DBOUT "   expected var %s (nonrepeater %d/%d)\n",
		  __snprint_oid(context->req_oids[pix].req_oid,
			 context->req_oids[pix].req_len),
		  pix, context->non_reps));
	DBPRT(2, (DBOUT "   received var %s\n",
		  __snprint_oid(vars->name, vars->name_length)));

	 /* This non-repeater has now been seen, so mark the sub-tree as
	 ** completed.  Note that this may not be the same oid as requested,
	 ** since non-repeaters act like GETNEXT requests, not GET's. <sigh>
	 */
	 context->req_oids[pix].complete = 1;
	 context->req_remain --;

      } else {		/* Must be a repeater variable. */

	DBPRT(2, (DBOUT "   received oid %s\n",
		  __snprint_oid(vars->name, vars->name_length)));

	 /* Are we already done with this tree?  If so, just ignore this
	 ** variable and move on to the next expected variable.
	 */
	 if (expect->complete) {