PCAP_SETDIRECTION(3)   FreeBSD Library Functions Manual   PCAP_SETDIRECTION(3)

NAME
       pcap_setdirection - set the direction for which packets will be
       captured

SYNOPSIS
       #include <pcap/pcap.h>

       int pcap_setdirection(pcap_t *p, pcap_direction_t d);

DESCRIPTION
       pcap_setdirection() is used to specify a direction that packets will be
       captured.  d is one of the constants PCAP_D_IN, PCAP_D_OUT or
       PCAP_D_INOUT.  PCAP_D_IN will only capture packets received by the
       device, PCAP_D_OUT will only capture packets sent by the device and
       PCAP_D_INOUT will capture packets received by or sent by the device.
       PCAP_D_INOUT is the default setting if this function is not called.

       pcap_setdirection() isn't necessarily fully supported on all platforms;
       some platforms might return an error for all values, and some other
       platforms might not support PCAP_D_OUT.

       This operation is not supported if a ``savefile'' is being read.

RETURN VALUE
       pcap_setdirection() returns 0 on success and PCAP_ERROR on failure. If
       PCAP_ERROR is returned, pcap_geterr(3) or pcap_perror(3) may be called
       with p as an argument to fetch or display the error text.

SEE ALSO
       pcap(3)

                                 25 July 2018             PCAP_SETDIRECTION(3)