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PCAP_INJECT(3)             Library Functions Manual             PCAP_INJECT(3)

       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(3) 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.)

       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(3) or pcap_perror(3) may be
       called with p as an argument to fetch or display the error text.


                                 25 July 2018                   PCAP_INJECT(3)