Commit | Line | Data |
---|---|---|
de0d3203 PA |
1 | .\" Copyright (c) 1994, 1996, 1997 |
2 | .\" The Regents of the University of California. All rights reserved. | |
3 | .\" | |
4 | .\" Redistribution and use in source and binary forms, with or without | |
5 | .\" modification, are permitted provided that: (1) source code distributions | |
6 | .\" retain the above copyright notice and this paragraph in its entirety, (2) | |
7 | .\" distributions including binary code include the above copyright notice and | |
8 | .\" this paragraph in its entirety in the documentation or other materials | |
9 | .\" provided with the distribution, and (3) all advertising materials mentioning | |
10 | .\" features or use of this software display the following acknowledgement: | |
11 | .\" ``This product includes software developed by the University of California, | |
12 | .\" Lawrence Berkeley Laboratory and its contributors.'' Neither the name of | |
13 | .\" the University nor the names of its contributors may be used to endorse | |
14 | .\" or promote products derived from this software without specific prior | |
15 | .\" written permission. | |
16 | .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED | |
17 | .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF | |
18 | .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. | |
19 | .\" | |
97a9217a | 20 | .TH PCAP_DATALINK 3PCAP "7 April 2014" |
de0d3203 PA |
21 | .SH NAME |
22 | pcap_datalink \- get the link-layer header type | |
23 | .SH SYNOPSIS | |
24 | .nf | |
25 | .ft B | |
26 | #include <pcap/pcap.h> | |
27 | .ft | |
28 | .LP | |
29 | .ft B | |
30 | int pcap_datalink(pcap_t *p); | |
31 | .ft | |
32 | .fi | |
33 | .SH DESCRIPTION | |
ea16f64e | 34 | .BR pcap_datalink () |
a85e14b0 | 35 | returns the link-layer header type for the live capture or ``savefile'' |
de0d3203 PA |
36 | specified by |
37 | .IR p . | |
97a9217a AHJ |
38 | .PP |
39 | It must not be called on a pcap descriptor created by | |
ea16f64e | 40 | .BR \%pcap_create (3PCAP) |
97a9217a | 41 | that has not yet been activated by |
ea16f64e | 42 | .BR \%pcap_activate (3PCAP). |
97a9217a | 43 | .PP |
3a289941 | 44 | .I https://www.tcpdump.org/linktypes.html |
97a9217a | 45 | lists the values |
ea16f64e | 46 | .BR pcap_datalink () |
97a9217a AHJ |
47 | can return and describes the packet formats that |
48 | correspond to those values. | |
49 | .PP | |
50 | Do | |
51 | .B NOT | |
52 | assume that the packets for a given capture or ``savefile`` will have | |
53 | any given link-layer header type, such as | |
54 | .B DLT_EN10MB | |
55 | for Ethernet. For example, the "any" device on Linux will have a | |
56 | link-layer header type of | |
57 | .B DLT_LINUX_SLL | |
ea16f64e AHJ |
58 | or |
59 | .B DLT_LINUX_SLL2 | |
97a9217a AHJ |
60 | even if all devices on the system at the time the "any" device is opened |
61 | have some other data link type, such as | |
62 | .B DLT_EN10MB | |
63 | for Ethernet. | |
64 | .SH RETURN VALUE | |
ea16f64e | 65 | .BR pcap_datalink () |
97a9217a AHJ |
66 | returns the link-layer header type on success and |
67 | .B PCAP_ERROR_NOT_ACTIVATED | |
68 | if called on a capture handle that has been created but not activated. | |
de0d3203 | 69 | .SH SEE ALSO |
ea16f64e AHJ |
70 | .BR pcap (3PCAP), |
71 | .BR pcap-linktype (@MAN_MISC_INFO@) |