pcap_inject(3pcap) — Linux manual page


PCAP_INJECT(3PCAP)                                        PCAP_INJECT(3PCAP)

NAME         top

       pcap_inject, pcap_sendpacket - transmit a packet

SYNOPSIS         top

       #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         top

       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.  Both are
       provided for compatibility.)

RETURN VALUE         top

       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

SEE ALSO         top


COLOPHON         top

       This page is part of the libpcap (packet capture library) project.
       Information about the project can be found at 
       ⟨http://www.tcpdump.org/⟩.  If you have a bug report for this manual
       page, see ⟨http://www.tcpdump.org/#patches⟩.  This page was obtained
       from the project's upstream Git repository
       ⟨https://github.com/the-tcpdump-group/libpcap.git⟩ on 2020-09-18.
       (At that time, the date of the most recent commit that was found in
       the repository was 2020-09-15.)  If you discover any rendering prob‐
       lems in this HTML version of the page, or you believe there is a bet‐
       ter or more up-to-date source for the page, or you have corrections
       or improvements to the information in this COLOPHON (which is not
       part of the original manual page), send a mail to man-pages@man7.org

                                25 July 2018              PCAP_INJECT(3PCAP)