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pcap_setfilter(3) [netbsd man page]

PCAP_SETFILTER(3)					     Library Functions Manual						 PCAP_SETFILTER(3)

NAME
pcap_setfilter - set the filter SYNOPSIS
#include <pcap/pcap.h> int pcap_setfilter(pcap_t *p, struct bpf_program *fp); DESCRIPTION
pcap_setfilter() is used to specify a filter program. fp is a pointer to a bpf_program struct, usually the result of a call to pcap_com- pile(). RETURN VALUE
pcap_setfilter() 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. SEE ALSO
pcap(3), pcap_compile(3), pcap_geterr(3) 5 April 2008 PCAP_SETFILTER(3)

Check Out this Related Man Page

PCAP_COMPILE(3PCAP)													       PCAP_COMPILE(3PCAP)

NAME
pcap_compile - compile a filter expression SYNOPSIS
#include <pcap/pcap.h> int pcap_compile(pcap_t *p, struct bpf_program *fp, const char *str, int optimize, bpf_u_int32 netmask); DESCRIPTION
pcap_compile() is used to compile the string str into a filter program. See pcap-filter(7) for the syntax of that string. program is a pointer to a bpf_program struct and is filled in by pcap_compile(). optimize controls whether optimization on the resulting code is per- formed. netmask specifies the IPv4 netmask of the network on which packets are being captured; it is used only when checking for IPv4 broadcast addresses in the filter program. If the netmask of the network on which packets are being captured isn't known to the program, or if packets are being captured on the Linux "any" pseudo-interface that can capture on more than one network, a value of PCAP_NET- MASK_UNKNOWN can be supplied; tests for IPv4 broadcast addresses will fail to compile, but all other tests in the filter program will be OK. RETURN VALUE
pcap_compile() returns 0 on success and -1 on failure. If -1 is returned, pcap_geterr() or pcap_perror() may be called with p as an argu- ment to fetch or display the error text. SEE ALSO
pcap(3PCAP), pcap_setfilter(3PCAP), pcap_freecode(3PCAP), pcap_geterr(3PCAP), pcap-filter(7) 5 April 2008 PCAP_COMPILE(3PCAP)
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