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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO | COLOPHON |
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PCAP_INJECT(3PCAP) PCAP_INJECT(3PCAP)
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(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. The same limitation applies to pcap_create(3PCAP) and
pcap_activate(3PCAP). 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.)
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.
pcap(3PCAP)
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 2025-02-02.
(At that time, the date of the most recent commit that was found
in the repository was 2025-01-31.) 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
man-pages@man7.org
23 November 2024 PCAP_INJECT(3PCAP)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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