xref: /netbsd-src/external/bsd/libpcap/dist/pcap-common.h (revision d16b7486a53dcb8072b60ec6fcb4373a2d0c27b7)
1 /*	$NetBSD: pcap-common.h,v 1.3 2018/09/03 15:26:43 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1993, 1994, 1995, 1996, 1997
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that: (1) source code distributions
9  * retain the above copyright notice and this paragraph in its entirety, (2)
10  * distributions including binary code include the above copyright notice and
11  * this paragraph in its entirety in the documentation or other materials
12  * provided with the distribution, and (3) all advertising materials mentioning
13  * features or use of this software display the following acknowledgement:
14  * ``This product includes software developed by the University of California,
15  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16  * the University nor the names of its contributors may be used to endorse
17  * or promote products derived from this software without specific prior
18  * written permission.
19  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22  *
23  * pcap-common.h - common code for pcap and pcapng files
24  */
25 
26 /*
27  * We use the "receiver-makes-right" approach to byte order,
28  * because time is at a premium when we are writing the file.
29  * In other words, the pcap_file_header and pcap_pkthdr,
30  * records are written in host byte order.
31  * Note that the bytes of packet data are written out in the order in
32  * which they were received, so multi-byte fields in packets are not
33  * written in host byte order, they're written in whatever order the
34  * sending machine put them in.
35  *
36  * ntoh[ls] aren't sufficient because we might need to swap on a big-endian
37  * machine (if the file was written in little-end order).
38  */
39 #define	SWAPLONG(y) \
40     (((((u_int)(y))&0xff)<<24) | \
41      ((((u_int)(y))&0xff00)<<8) | \
42      ((((u_int)(y))&0xff0000)>>8) | \
43      ((((u_int)(y))>>24)&0xff))
44 #define	SWAPSHORT(y) \
45      ((u_short)(((((u_int)(y))&0xff)<<8) | \
46                 ((((u_int)(y))&0xff00)>>8)))
47 
48 extern int dlt_to_linktype(int dlt);
49 
50 extern int linktype_to_dlt(int linktype);
51 
52 extern void swap_pseudo_headers(int linktype, struct pcap_pkthdr *hdr,
53     u_char *data);
54 
55 extern u_int max_snaplen_for_dlt(int dlt);
56