pcap_stats(3) - NetBSD Manual Pages

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PCAP_STATS(3)                                                    PCAP_STATS(3)




NAME

       pcap_stats - get capture statistics


SYNOPSIS

       #include <pcap/pcap.h>

       int pcap_stats(pcap_t *p, struct pcap_stat *ps);


DESCRIPTION

       pcap_stats()  fills  in  the  struct pcap_stat pointed to by its second
       argument.  The values represent packet statistics from the start of the
       run to the time of the call.

       pcap_stats()  is supported only on live captures, not on ``savefiles'';
       no statistics are stored in ``savefiles'', so no statistics are  avail-
       able when reading from a ``savefile''.

       A struct pcap_stat has the following members:

              ps_recv
                     number of packets received;

              ps_drop
                     number  of  packets  dropped because there was no room in
                     the operating system's buffer when they arrived,  because
                     packets weren't being read fast enough;

              ps_ifdrop
                     number of packets dropped by the network interface or its
                     driver.

       The statistics do not behave the same way on  all  platforms.   ps_recv
       might  count  packets whether they passed any filter set with pcap_set-
       filter(3) or not, or it might count only packets that pass the  filter.
       It also might, or might not, count packets dropped because there was no
       room in the operating system's buffer when they  arrived.   ps_drop  is
       not  available on all platforms; it is zero on platforms where it's not
       available.  If packet filtering is done in libpcap, rather than in  the
       operating  system,  it  would count packets that don't pass the filter.
       Both ps_recv and ps_drop might, or might not,  count  packets  not  yet
       read  from  the  operating system and thus not yet seen by the applica-
       tion.  ps_ifdrop might, or might not, be  implemented;  if  it's  zero,
       that  might  mean  that no packets were dropped by the interface, or it
       might mean that the statistic is  unavailable,  so  it  should  not  be
       treated as an indication that the interface did not drop any packets.


RETURN VALUE

       pcap_stats()  returns  0 on success and returns -1 if there is an error
       or if  p  doesn't  support  packet  statistics.   If  -1  is  returned,
       pcap_geterr()  or  pcap_perror() may be called with p as an argument to
       fetch or display the error text.


SEE ALSO

       pcap(3), pcap_geterr(3)



                               7 September 2009                  PCAP_STATS(3)