NAME¶
pcap_inject, pcap_sendpacket - transmit a packet
SYNOPSIS¶
#include <pcap/pcap.h>
int pcap_inject(pcap_t *p, const void *buf, size_t size);
int pcap_sendpacket(pcap_t *p, const u_char *buf, int size);
DESCRIPTION¶
pcap_inject() sends a raw packet through the network interface;
buf points to the data of the packet, including the link-layer header,
and
size is the number of bytes in the packet.
Note that, even if you successfully open the network interface, you might not
have permission to send packets on it, or it might not support sending
packets; as
pcap_open_live() doesn't have a flag to indicate whether to
open for capturing, sending, or capturing and sending, you cannot request an
open that supports sending and be notified at open time whether sending will
be possible. Note also that some devices might not support sending packets.
Note that, on some platforms, the link-layer header of the packet that's sent
might not be the same as the link-layer header of the packet supplied to
pcap_inject(), as the source link-layer address, if the header contains
such an address, might be changed to be the address assigned to the interface
on which the packet it sent, if the platform doesn't support sending
completely raw and unchanged packets. Even worse, some drivers on some
platforms might change the link-layer type field to whatever value libpcap
used when attaching to the device, even on platforms that
do nominally
support sending completely raw and unchanged packets.
pcap_sendpacket() is like
pcap_inject(), but it returns 0 on
success, rather than returning the number of bytes written.
(
pcap_inject() comes from OpenBSD;
pcap_sendpacket() comes from
WinPcap. Both are provided for compatibility.)
RETURN VALUE¶
pcap_inject() returns the number of bytes written on success and -1 on
failure.
pcap_sendpacket() returns 0 on success and -1 on failure.
If -1 is returned,
pcap_geterr() or
pcap_perror() may be called
with
p as an argument to fetch or display the error text.
SEE ALSO¶
pcap(3PCAP), pcap_geterr(3PCAP)