/* Copyright (c) 2002-2009 InMon Corp. Licensed under the terms of the InMon sFlow licence: */
/* http://www.inmon.com/technology/sflowlicense.txt */

#include "sflow_api.h"

/*_________________--------------------------__________________
  _________________    sfl_poller_init       __________________
  -----------------__________________________------------------
*/

void sfl_poller_init(SFLPoller *poller,
		     SFLAgent *agent,
		     SFLDataSource_instance *pdsi,
		     void *magic,         /* ptr to pass back in getCountersFn() */
		     getCountersFn_t getCountersFn)
{
    /* copy the dsi in case it points to poller->dsi, which we are about to clear */
    SFLDataSource_instance dsi = *pdsi;

    /* preserve the *nxt pointer too, in case we are resetting this poller and it is
       already part of the agent's linked list (thanks to Matt Woodly for pointing this out) */
    SFLPoller *nxtPtr = poller->nxt;

    /* clear everything */
    memset(poller, 0, sizeof(*poller));
  
    /* restore the linked list ptr */
    poller->nxt = nxtPtr;
  
    /* now copy in the parameters */
    poller->agent = agent;
    poller->dsi = dsi; /* structure copy */
    poller->magic = magic;
    poller->getCountersFn = getCountersFn;
}

/*_________________--------------------------__________________
  _________________       reset              __________________
  -----------------__________________________------------------
*/

static void reset(SFLPoller *poller)
{
    SFLDataSource_instance dsi = poller->dsi;
    sfl_poller_init(poller, poller->agent, &dsi, poller->magic, poller->getCountersFn);
}

/*_________________---------------------------__________________
  _________________      MIB access           __________________
  -----------------___________________________------------------
*/
u_int32_t sfl_poller_get_sFlowCpReceiver(SFLPoller *poller) {
    return poller->sFlowCpReceiver;
}

void sfl_poller_set_sFlowCpReceiver(SFLPoller *poller, u_int32_t sFlowCpReceiver) {
    poller->sFlowCpReceiver = sFlowCpReceiver;
    if(sFlowCpReceiver == 0) reset(poller);
    else {
	/* retrieve and cache a direct pointer to my receiver */
	poller->myReceiver = sfl_agent_getReceiver(poller->agent, poller->sFlowCpReceiver);
    }
}

u_int32_t sfl_poller_get_sFlowCpInterval(SFLPoller *poller) {
    return poller->sFlowCpInterval;
}

void sfl_poller_set_sFlowCpInterval(SFLPoller *poller, u_int32_t sFlowCpInterval) {
    poller->sFlowCpInterval = sFlowCpInterval;
    /* Set the countersCountdown to be a randomly selected value between 1 and
       sFlowCpInterval. That way the counter polling would be desynchronised
       (on a 200-port switch, polling all the counters in one second could be harmful). */
    poller->countersCountdown = 1 + (random() % sFlowCpInterval);
}

/*_________________---------------------------------__________________
  _________________          bridge port            __________________
  -----------------_________________________________------------------
  May need a separate number to reference the local bridge port
  to get counters if it is not the same as the global ifIndex.
*/

void sfl_poller_set_bridgePort(SFLPoller *poller, u_int32_t port_no) {
    poller->bridgePort = port_no;
}

u_int32_t sfl_poller_get_bridgePort(SFLPoller *poller) {
    return poller->bridgePort;
}

/*_________________---------------------------------__________________
  _________________   sequence number reset         __________________
  -----------------_________________________________------------------
  Used to indicate a counter discontinuity
  so that the sflow collector will know to ignore the next delta.
*/
void sfl_poller_resetCountersSeqNo(SFLPoller *poller) {  poller->countersSampleSeqNo = 0; }

/*_________________---------------------------__________________
  _________________    sfl_poller_tick        __________________
  -----------------___________________________------------------
*/

void sfl_poller_tick(SFLPoller *poller, time_t now)
{
    if(poller->countersCountdown == 0) return; /* counters retrieval was not enabled */
    if(poller->sFlowCpReceiver == 0) return;

    if(--poller->countersCountdown == 0) {
	if(poller->getCountersFn != NULL) {
	    /* call out for counters */
	    SFL_COUNTERS_SAMPLE_TYPE cs;
	    memset(&cs, 0, sizeof(cs));
	    poller->getCountersFn(poller->magic, poller, &cs);
	    /* this countersFn is expected to fill in some counter block elements
	       and then call sfl_poller_writeCountersSample(poller, &cs); */
	}
	/* reset the countdown */
	poller->countersCountdown = poller->sFlowCpInterval;
    }
}

/*_________________---------------------------------__________________
  _________________ sfl_poller_writeCountersSample  __________________
  -----------------_________________________________------------------
*/

void sfl_poller_writeCountersSample(SFLPoller *poller, SFL_COUNTERS_SAMPLE_TYPE *cs)
{
    /* fill in the rest of the header fields, and send to the receiver */
    cs->sequence_number = ++poller->countersSampleSeqNo;
#ifdef SFL_USE_32BIT_INDEX
    cs->ds_class = SFL_DS_CLASS(poller->dsi);
    cs->ds_index = SFL_DS_INDEX(poller->dsi);
#else
    cs->source_id = SFL_DS_DATASOURCE(poller->dsi);
#endif
    /* sent to my receiver */
    if(poller->myReceiver) sfl_receiver_writeCountersSample(poller->myReceiver, cs);
}