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.
struct pcap_stat has the following members:
number of packets received;
number of packets dropped because there was no room in the operating
systems buffer when they arrived, because packets werent being read
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
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 systems buffer when they arrived.
ps_drop is not available on all platforms; it is zero on platforms where its
not available. If packet filtering is done in libpcap, rather than in
the operating system, it would count packets that dont pass the filter.
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 its 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.