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() doesnt 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 thats
sent might not be the same as the link-layer header of the packet
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 doesnt 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
(pcap_inject() comes from OpenBSD;
pcap_sendpacket() comes from WinPcap. Both are provided for compatibility.)