pcap_datalink(3pcap) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO | COLOPHON

PCAP_DATALINK(3PCAP)                                    PCAP_DATALINK(3PCAP)

NAME         top

       pcap_datalink - get the link-layer header type

SYNOPSIS         top

       #include <pcap/pcap.h>

       int pcap_datalink(pcap_t *p);

DESCRIPTION         top

       pcap_datalink() returns the link-layer header type for the live
       capture or ``savefile'' specified by p.

       It must not be called on a pcap descriptor created by
       pcap_create(3PCAP) that has not yet been activated by
       pcap_activate(3PCAP).

       https://www.tcpdump.org/linktypes.html  lists the values
       pcap_datalink() can return and describes the packet formats that
       correspond to those values.

       Do NOT assume that the packets for a given capture or ``savefile``
       will have any given link-layer header type, such as DLT_EN10MB for
       Ethernet.  For example, the "any" device on Linux will have a link-
       layer header type of DLT_LINUX_SLL or DLT_LINUX_SLL2 even if all
       devices on the system at the time the "any" device is opened have
       some other data link type, such as DLT_EN10MB for Ethernet.

RETURN VALUE         top

       pcap_datalink() returns the link-layer header type on success and
       PCAP_ERROR_NOT_ACTIVATED if called on a capture handle that has been
       created but not activated.

SEE ALSO         top

       pcap(3PCAP), pcap-linktype(7)

COLOPHON         top

       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 2020-09-18.
       (At that time, the date of the most recent commit that was found in
       the repository was 2020-09-15.)  If you discover any rendering prob‐
       lems in this HTML version of the page, or you believe there is a bet‐
       ter 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

                                7 April 2014            PCAP_DATALINK(3PCAP)