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 available 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_setfilter(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 application.
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)