You probably can’t; these stats are maintained within the SNMP agent in a
static array (defined in snmplib/snmp_api.c, and there’s no programmatic access
to it other than through the agent interface that’s going to increment the
counters.
From: Gustav Evertsson [mailto:m...@guzzzt.com]
Sent: Thursday, May 02, 2013 11:49 PM
To: Tim Cox
Cc: net-snmp-coders@lists.sourceforge.net
Subject: Re: Access the SNMP Counters without increasing them
Thank you very much for the help.
My main issue is not to send the data to the GUI, the problem is to get it out
of the net-snmp library. The "find your data" part in your suggestion. How do I
read snmpInPkts, snmpOutPkts etc out of the library from C function calls?
/Gustav
On Thu, 2 May 2013 23:44:26 +0200
Tim Cox <timmiles...@gmx.ch> wrote:
>
>
>
> It really depends on being able to see your agent's data from a
> program which is not itself SNMP and using sockets which are not
> SNMP's sockets
>
> I'm assuming you are talking about two different machines, one
> containing an agent and the other a manager
>
> You want to interrogate data which is in the SNMP agent's space
> without actually being that agent. If you are talking about an
> embedded system with a flat global address space, this is easy.
> Otherwise you may find it best to include your piece of enquiry code
> in your agent
>
> It doesn't sound important to me at all, but this is how you do it
>
> you don't use SNMP's sockets. You use one of the other 60000
> available socket addresses on the target system
>
> It will be easiest if your new piece of code is a thread of the agent
>
> #include <sys/socket.h>
> #include <netinet/in.h>
> #include <errno.h>
>
> static struct sockaddr_in here = { AF_INET,
> HTONS(A_NICE_PORT_NUMBER_MAYBE_44004) } ;
> static struct sockaddr_in there = { AF_INET } ;
> static int sixteen = 16;
>
> void listener()
> {
> int s = socket(AF_INET, SOCK_DGRAM);
> int x = bind(s, (struct sockaddr *) &here, 16);
>
> char data[DATA];
>
> if (s < 0) printf("yon's mingin\n");
> else
> {
> if (x < 0) printf("yon's awfu\n");
> else
> {
> for (;;)
> {
> x = recvfrom(s, data, DATA, 0, (struct sockaddr *)
> &there, &sixteen);
> if (x < 0) break
>
>
> /************************************************************************
>
> find your data and format your response
>
>
> ************************************************************************/
>
> x = send(s, data, HOWEVER_LONG_YOUR_RESPONSE_IS, 0,
> (struct sockaddr *) &there, 16);
> }
>
> printf("listener stopped %d\n", errno);
> }
> }
> }
>
> and you need something in your GUI program to call this listener.
> Decide for yourself if it should block on response. I don't advise
> it. But I don't advise you to make this feature of your application
> so important in the first place
>
> #include <sys/socket.h>
> #include <netinet/in.h>
> #include <errno.h>
>
> int requestor(char *data)
> {
> static struct sockaddr_in there = { AF_INET,
> HTONS(A_NICE_PORT_NUMBER_MAYBE_44004),
> {
> REMOTE_NETWORK_ADDRESS } } ;
> static struct sockaddr_in here = { AF_INET } ;
> static int sixteen = 16;
>
> static int s = -1;
>
> int x;
>
>
> if (s < 0)
> {
> s = socket(AF_INET, SOCK_DGRAM);
>
> if (s < 0) return -1;
>
> x = bind(s, (struct sockaddr *) &here, 16);
> if (x < 0)
> {
> s = -1;
> return -2
> }
> }
>
> x = sendto(s, data, sizeof(enquiry), 0, (struct sockaddr *)
> &there, 16);
> of (x < 0) return -3;
> x = recvfrom(s, data, MAXIMUM, 0, (struct sockaddr *), &there,
> &sixteen);
> if (x < 0) return -4;
> return x;
> }
>
>
>
>
> Am 02.05.2013 um 08:39 schrieb Gustav Evertsson:
>
> >
> > Can you describe the socket method a bit more? I have tested to
> implement it with these calls, but that will increase the counters:
> >
> > snmp_sess_init( &session );
> > session.peername = "127.0.0.1";
> > ....
> > SOCK_STARTUP;
> > ss = snmp_open(&session);
> > snmp_synch_response(ss, pdu, &response);
> > snmp_close(ss);
> > SOCK_CLEANUP;
> >
> > /Gustav
> >
> > On Tue, 30 Apr 2013 15:44:56 +0200 (CEST)
> > "Tim Cox" <timmiles...@gmx.ch> wrote:
> > > If this is really so important access the MIB
> variables
> > > from a socket program or decrement the send and receive
> counts by
> > > 1 between acquiring and displaying (you need a running count of
> > > course) Gesendet: Dienstag, 30. April 2013 um 15:35 Uhr
> Von:
> > > "Gustav Evertsson" <m...@guzzzt.com> An: "Tim Cox"
> <timmiles...@gmx.ch>
> > > Cc: net-snmp-coders@lists.sourceforge.net Betreff: Re: Access the
> > > SNMP Counters without increasing them Yes, the problem is that
> they
> > > are increased when read from the GUI. They should only be
> increased
> > > when read from SNMP. When the user opens the GUI it is not
> visible
> > > that the counters comes from the SNMP interface and it therefore
> > > looks strange to the user. I could inform them that the request
> goes
> > > over SNMP and is therefore included but I would rather access the
> > > counters in a way that does not affect them. /Gustav On Tue,
> 30
> > > Apr 2013 13:10:11 +0200 (CEST) "Tim Cox" <timmiles...@gmx.ch>
> wrote:
> > > > It depends how your MIB is implemented You may be
> able
> > > to > see these counters from a simple socket application, maybe
> not >
> > > But how can it be so important? It should be reassuring that
> your
> > > > enquiry traffic is also shown. Do you want to avoid
> incrementing
> > > the > interface counters as well? Gesendet:
> Dienstag,
> > > 30. > April 2013 um 09:47 Uhr Von: "Gustav Evertsson"
> <m...@guzzzt.com>
> > > An: > net-snmp-coders@lists.sourceforge.net Betreff: Access the
> SNMP
> > > > Counters without increasing them I am developing an
> application >
> > > that have both an SNMP interface and a GUI. I would like to
> access >
> > > the SNMP counters like snmpInPkts, snmpOutPkts etc to show in the
> >
> > > GUI. I have tested to send SNMP request to localhost and it works
> but
> > > > it also increases the counters and is therefore not so nice. >
> > > Reloading the GUI will show increased counters even if there has
> been
> > > > no outside SNMP requests. Is there a way to access these
> counters
> > > by > some API call instead? I9m interested in the counters under
> >
> > > 1.3.6.1.2.1.11 and 1.3.6.1.6.3.15.1.1 and 1.3.6.1.6.3.11.2.1.
> > >
> >
>
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