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 2021-04-01.
       (At that time, the date of the most recent commit that was found
       in the repository was 2021-03-31.)  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

                              7 April 2014          PCAP_DATALINK(3PCAP)