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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO | COLOPHON |
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PCAP_SETFILTER(3PCAP) PCAP_SETFILTER(3PCAP)
pcap_setfilter - set the filter
#include <pcap/pcap.h>
int pcap_setfilter(pcap_t *p, struct bpf_program *fp);
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_compile(3PCAP).
If the calls to pcap_compile() and pcap_setfilter() use the same
pcap_t handle, packet filtering should either work correctly or
fail correctly without additional efforts. Otherwise the filter
program must have been compiled for the same link-layer header
type as the one used by the pcap_t handle, also on Linux any usage
of BPF extensions must match the use case. Specifically, if the
pcap_t stands for an input savefile, the filter program must not
use the extensions, but if it stands for a live packet capture,
the filter program may use the extensions if necessary. See
pcap_compile() for more information.
pcap_setfilter() returns 0 on success, PCAP_ERROR_NOT_ACTIVATED if
called on a capture handle that has been created but not
activated, or PCAP_ERROR on other errors. 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)
This page is part of the libpcap (packet capture library) project.
Information about the project can be found at
⟨http://www.tcpdump.org/⟩. If you have a bug report for this
manual page, see ⟨http://www.tcpdump.org/#patches⟩. This page was
obtained from the project's upstream Git repository
⟨https://github.com/the-tcpdump-group/libpcap.git⟩ on 2025-08-11.
(At that time, the date of the most recent commit that was found
in the repository was 2025-08-10.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
13 February 2025 PCAP_SETFILTER(3PCAP)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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