lib/sflow_poller.c

   1 /* Copyright (c) 2002-2009 InMon Corp. Licensed under the terms of the InMon sFlow licence: */
   2 /* http://www.inmon.com/technology/sflowlicense.txt */
   3
   4 #include "sflow_api.h"
   5
   6 /*_________________--------------------------__________________
   7   _________________    sfl_poller_init       __________________
   8   -----------------__________________________------------------
   9 */
  10
  11 void sfl_poller_init(SFLPoller *poller,
  12                      SFLAgent *agent,
  13                      SFLDataSource_instance *pdsi,
  14                      void *magic,         /* ptr to pass back in getCountersFn() */
  15                      getCountersFn_t getCountersFn)
  16 {
  17     /* copy the dsi in case it points to poller->dsi, which we are about to clear */
  18     SFLDataSource_instance dsi = *pdsi;
  19
  20     /* preserve the *nxt pointer too, in case we are resetting this poller and it is
  21        already part of the agent's linked list (thanks to Matt Woodly for pointing this out) */
  22     SFLPoller *nxtPtr = poller->nxt;
  23
  24     /* clear everything */
  25     memset(poller, 0, sizeof(*poller));
  26
  27     /* restore the linked list ptr */
  28     poller->nxt = nxtPtr;
  29
  30     /* now copy in the parameters */
  31     poller->agent = agent;
  32     poller->dsi = dsi; /* structure copy */
  33     poller->magic = magic;
  34     poller->getCountersFn = getCountersFn;
  35 }
  36
  37 /*_________________--------------------------__________________
  38   _________________       reset              __________________
  39   -----------------__________________________------------------
  40 */
  41
  42 static void reset(SFLPoller *poller)
  43 {
  44     SFLDataSource_instance dsi = poller->dsi;
  45     sfl_poller_init(poller, poller->agent, &dsi, poller->magic, poller->getCountersFn);
  46 }
  47
  48 /*_________________---------------------------__________________
  49   _________________      MIB access           __________________
  50   -----------------___________________________------------------
  51 */
  52 u_int32_t sfl_poller_get_sFlowCpReceiver(SFLPoller *poller) {
  53     return poller->sFlowCpReceiver;
  54 }
  55
  56 void sfl_poller_set_sFlowCpReceiver(SFLPoller *poller, u_int32_t sFlowCpReceiver) {
  57     poller->sFlowCpReceiver = sFlowCpReceiver;
  58     if(sFlowCpReceiver == 0) reset(poller);
  59     else {
  60         /* retrieve and cache a direct pointer to my receiver */
  61         poller->myReceiver = sfl_agent_getReceiver(poller->agent, poller->sFlowCpReceiver);
  62     }
  63 }
  64
  65 u_int32_t sfl_poller_get_sFlowCpInterval(SFLPoller *poller) {
  66     return poller->sFlowCpInterval;
  67 }
  68
  69 void sfl_poller_set_sFlowCpInterval(SFLPoller *poller, u_int32_t sFlowCpInterval) {
  70     poller->sFlowCpInterval = sFlowCpInterval;
  71     /* Set the countersCountdown to be a randomly selected value between 1 and
  72        sFlowCpInterval. That way the counter polling would be desynchronised
  73        (on a 200-port switch, polling all the counters in one second could be harmful). */
  74     poller->countersCountdown = 1 + (random() % sFlowCpInterval);
  75 }
  76
  77 /*_________________---------------------------------__________________
  78   _________________          bridge port            __________________
  79   -----------------_________________________________------------------
  80   May need a separate number to reference the local bridge port
  81   to get counters if it is not the same as the global ifIndex.
  82 */
  83
  84 void sfl_poller_set_bridgePort(SFLPoller *poller, u_int32_t port_no) {
  85     poller->bridgePort = port_no;
  86 }
  87
  88 u_int32_t sfl_poller_get_bridgePort(SFLPoller *poller) {
  89     return poller->bridgePort;
  90 }
  91
  92 /*_________________---------------------------------__________________
  93   _________________   sequence number reset         __________________
  94   -----------------_________________________________------------------
  95   Used to indicate a counter discontinuity
  96   so that the sflow collector will know to ignore the next delta.
  97 */
  98 void sfl_poller_resetCountersSeqNo(SFLPoller *poller) {  poller->countersSampleSeqNo = 0; }
  99
 100 /*_________________---------------------------__________________
 101   _________________    sfl_poller_tick        __________________
 102   -----------------___________________________------------------
 103 */
 104
 105 void sfl_poller_tick(SFLPoller *poller, time_t now)
 106 {
 107     if(poller->countersCountdown == 0) return; /* counters retrieval was not enabled */
 108     if(poller->sFlowCpReceiver == 0) return;
 109
 110     if(--poller->countersCountdown == 0) {
 111         if(poller->getCountersFn != NULL) {
 112             /* call out for counters */
 113             SFL_COUNTERS_SAMPLE_TYPE cs;
 114             memset(&cs, 0, sizeof(cs));
 115             poller->getCountersFn(poller->magic, poller, &cs);
 116             /* this countersFn is expected to fill in some counter block elements
 117                and then call sfl_poller_writeCountersSample(poller, &cs); */
 118         }
 119         /* reset the countdown */
 120         poller->countersCountdown = poller->sFlowCpInterval;
 121     }
 122 }
 123
 124 /*_________________---------------------------------__________________
 125   _________________ sfl_poller_writeCountersSample  __________________
 126   -----------------_________________________________------------------
 127 */
 128
 129 void sfl_poller_writeCountersSample(SFLPoller *poller, SFL_COUNTERS_SAMPLE_TYPE *cs)
 130 {
 131     /* fill in the rest of the header fields, and send to the receiver */
 132     cs->sequence_number = ++poller->countersSampleSeqNo;
 133 #ifdef SFL_USE_32BIT_INDEX
 134     cs->ds_class = SFL_DS_CLASS(poller->dsi);
 135     cs->ds_index = SFL_DS_INDEX(poller->dsi);
 136 #else
 137     cs->source_id = SFL_DS_DATASOURCE(poller->dsi);
 138 #endif
 139     /* sent to my receiver */
 140     if(poller->myReceiver) sfl_receiver_writeCountersSample(poller->myReceiver, cs);
 141 }
 142