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/Npcap.  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 text.

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 2021-08-27.
       (At that time, the date of the most recent commit that was found
       in the repository was 2021-08-17.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better 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

                              25 July 2018            PCAP_INJECT(3PCAP)