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(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.)

RETURN VALUE

       pcap_inject()  returns the number of bytes written on success, PCAP_ERROR_NOT_ACTIVATED if
       called on a capture handle that has been created but  not  activated,  and  PCAP_ERROR  on
       other errors.

       pcap_sendpacket()  returns  0  on success, PCAP_ERROR_NOT_ACTIVATED if called on a capture
       handle that has been created but not activated, and PCAP_ERROR on other errors.

       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.

SEE ALSO

       pcap(3PCAP)

                                           5 March 2022                        PCAP_INJECT(3PCAP)