PCAP_OFFLINE_FILTER(3PCAP)PCAP_OFFLINE_FILTER(3PCAP)NAME
pcap_offline_filter - check whether a filter matches a packet
SYNOPSIS
#include <pcap/pcap.h>
int pcap_offline_filter(struct bpf_program *fp,
const struct pcap_pkthdr *h, const u_char *pkt)
DESCRIPTION
pcap_offline_filter() checks whether a filter matches a packet. fp is a pointer to a bpf_program struct, usually the result of a call to
pcap_compile(). h points to the pcap_pkthdr structure for the packet, and pkt points to the data in the packet.
RETURN VALUE
pcap_offline_filter() returns the return value of the filter program. This will be zero if the packet doesn't match the filter and non-
zero if the packet matches the filter.
SEE ALSO pcap(3PCAP), pcap_compile(3PCAP)
13 May 2008 PCAP_OFFLINE_FILTER(3PCAP)
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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