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68 lines
2.4 KiB
68 lines
2.4 KiB
.\" 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_DATALINK 3PCAP "7 April 2014" |
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.SH NAME |
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pcap_datalink \- get the link-layer header type |
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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_datalink(pcap_t *p); |
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.ft |
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.fi |
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.SH DESCRIPTION |
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.B pcap_datalink() |
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returns the link-layer header type for the live capture or ``savefile'' |
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specified by |
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.IR p . |
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.PP |
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It must not be called on a pcap descriptor created by |
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.B pcap_create() |
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that has not yet been activated by |
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.BR pcap_activate() . |
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.PP |
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.I http://www.tcpdump.org/linktypes.html |
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lists the values |
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.B pcap_datalink() |
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can return and describes the packet formats that |
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correspond to those values. |
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.PP |
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Do |
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.B NOT |
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assume that the packets for a given capture or ``savefile`` will have |
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any given link-layer header type, such as |
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.B DLT_EN10MB |
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for Ethernet. For example, the "any" device on Linux will have a |
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link-layer header type of |
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.B DLT_LINUX_SLL |
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even if all devices on the system at the time the "any" device is opened |
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have some other data link type, such as |
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.B DLT_EN10MB |
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for Ethernet. |
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.SH RETURN VALUE |
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.B pcap_datalink() |
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returns the link-layer header type on success and |
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.B PCAP_ERROR_NOT_ACTIVATED |
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if called on a capture handle that has been created but not activated. |
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.SH SEE ALSO |
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pcap(3PCAP), pcap-linktype(@MAN_MISC_INFO@)
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