pcap_datalink(3) - NetBSD Manual Pages

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PCAP_DATALINK(3)                                              PCAP_DATALINK(3)




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(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 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(3), pcap-linktype(7)



                                 7 April 2014                 PCAP_DATALINK(3)