Manpages - pcap_setdirection.3pcap

pcap_setdirection - set the direction for which packets will be captured

  #include <pcap/pcap.h>
  int pcap_setdirection(pcap_t *p, pcap_direction_t d);

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.

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

*pcap*(3PCAP)