Copyright (c) 1994, 1996, 1997
The Regents of the University of California. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that: (1) source code distributions
retain the above copyright notice and this paragraph in its entirety, (2)
distributions including binary code include the above copyright notice and
this paragraph in its entirety in the documentation or other materials
provided with the distribution, and (3) all advertising materials mentioning
features or use of this software display the following acknowledgement:
``This product includes software developed by the University of California,
Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
the University nor the names of its contributors may be used to endorse
or promote products derived from this software without specific prior
written permission.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

pcap_inject, pcap_sendpacket - transmit a packet

#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);

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 (3PCAP) 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/Npcap. Both are provided for compatibility.)

pcap_inject () returns the number of bytes written on success and PCAP_ERROR on failure.

pcap_sendpacket () returns 0 on success and PCAP_ERROR on failure.

If PCAP_ERROR is returned, pcap_geterr (3PCAP) or pcap_perror (3PCAP) may be called with p as an argument to fetch or display the error text.

pcap (3PCAP)