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)