NAME

       pcap_datalink - get the link-layer header type

SYNOPSIS

       #include <pcap/pcap.h>

       int pcap_datalink(pcap_t *p);

DESCRIPTION

       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

       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

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

                                                  7 April 2014                              PCAP_DATALINK(3PCAP)