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() that
has not yet been activated by
pcap_activate().
http://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(3PCAP),
pcap-linktype(7)