PCAP_SETDIRECTION(3) Library Functions Manual PCAP_SETDIRECTION(3)
pcap_setdirection - set the direction for which packets will be
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 -1 on failure. If -1 is
returned, pcap_geterr() or pcap_perror() may be called with p as an
argument to fetch or display the error text.
5 April 2008 PCAP_SETDIRECTION(3)