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pcap_datalink(3)                                      pcap_datalink(3)




NAME

       pcap_datalink - get the link-layer header type


SYNOPSIS

       #include <pcap/pcap.h>

       pcap_datalink(3) *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(3)    that    has    not    yet   been   activated   by
       pcap_activate(3).

       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 sys-
       tem 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(3), pcap-linktype(7)



                                 7 April 2014             pcap_datalink(3)

libpcap 1.10.0 - Generated Thu Dec 31 13:20:05 CST 2020
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