95 lines
3.3 KiB
Plaintext
95 lines
3.3 KiB
Plaintext
.\" Copyright (c) 1994, 1996, 1997
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that: (1) source code distributions
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.\" retain the above copyright notice and this paragraph in its entirety, (2)
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.\" distributions including binary code include the above copyright notice and
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.\" this paragraph in its entirety in the documentation or other materials
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.\" provided with the distribution, and (3) all advertising materials mentioning
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.\" features or use of this software display the following acknowledgement:
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.\" ``This product includes software developed by the University of California,
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.\" Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
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.\" the University nor the names of its contributors may be used to endorse
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.\" or promote products derived from this software without specific prior
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.\" written permission.
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.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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.\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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.\"
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.TH PCAP_INJECT 3PCAP "25 July 2018"
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.SH NAME
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pcap_inject, pcap_sendpacket \- transmit a packet
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.SH SYNOPSIS
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.nf
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.ft B
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#include <pcap/pcap.h>
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.ft
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.LP
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.ft B
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int pcap_inject(pcap_t *p, const void *buf, size_t size);
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int pcap_sendpacket(pcap_t *p, const u_char *buf, int size);
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.ft
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.fi
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.SH DESCRIPTION
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.B pcap_inject()
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sends a raw packet through the network interface;
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.I buf
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points to the data of the packet, including the link-layer header, and
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.I size
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is the number of bytes in the packet.
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.PP
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Note that, even if you successfully open the network interface, you
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might not have permission to send packets on it, or it might not support
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sending packets; as
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.B pcap_open_live(3PCAP)
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doesn't have a flag to indicate whether to open for capturing, sending,
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or capturing and sending, you cannot request an open that supports
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sending and be notified at open time whether sending will be possible.
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Note also that some devices might not support sending packets.
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.PP
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Note that, on some platforms, the link-layer header of the packet that's
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sent might not be the same as the link-layer header of the packet
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supplied to
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.BR pcap_inject() ,
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as the source link-layer address, if the header contains such an
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address, might be changed to be the address assigned to the interface on
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which the packet it sent, if the platform doesn't support sending
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completely raw and unchanged packets. Even worse, some drivers on some
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platforms might change the link-layer type field to whatever value
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libpcap used when attaching to the device, even on platforms that
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.I do
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nominally support sending completely raw and unchanged packets.
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.PP
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.B pcap_sendpacket()
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is like
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.BR pcap_inject() ,
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but it returns 0 on success, rather than returning the number of bytes
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written.
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.RB ( pcap_inject()
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comes from OpenBSD;
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.B pcap_sendpacket()
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comes from WinPcap. Both are provided for compatibility.)
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.SH RETURN VALUE
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.B pcap_inject()
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returns the number of bytes written on success and
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.B PCAP_ERROR
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on failure.
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.PP
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.B pcap_sendpacket()
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returns 0 on success and
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.B PCAP_ERROR
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on failure.
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.PP
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If
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.B PCAP_ERROR
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is returned,
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.B pcap_geterr(3PCAP)
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or
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.B pcap_perror(3PCAP)
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may be called with
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.I p
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as an argument to fetch or display the error text.
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.SH SEE ALSO
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pcap(3PCAP)
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