xref: /freebsd/contrib/libpcap/pcap-common.h (revision a25896ca1270e25b657ceaa8d47d5699515f5c25)
1 /*
2  * Copyright (c) 1993, 1994, 1995, 1996, 1997
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that: (1) source code distributions
7  * retain the above copyright notice and this paragraph in its entirety, (2)
8  * distributions including binary code include the above copyright notice and
9  * this paragraph in its entirety in the documentation or other materials
10  * provided with the distribution, and (3) all advertising materials mentioning
11  * features or use of this software display the following acknowledgement:
12  * ``This product includes software developed by the University of California,
13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14  * the University nor the names of its contributors may be used to endorse
15  * or promote products derived from this software without specific prior
16  * written permission.
17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20  *
21  * pcap-common.h - common code for pcap and pcapng files
22  */
23 
24 /*
25  * We use the "receiver-makes-right" approach to byte order,
26  * because time is at a premium when we are writing the file.
27  * In other words, the pcap_file_header and pcap_pkthdr,
28  * records are written in host byte order.
29  * Note that the bytes of packet data are written out in the order in
30  * which they were received, so multi-byte fields in packets are not
31  * written in host byte order, they're written in whatever order the
32  * sending machine put them in.
33  *
34  * ntoh[ls] aren't sufficient because we might need to swap on a big-endian
35  * machine (if the file was written in little-end order).
36  */
37 #define	SWAPLONG(y) \
38 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
39 #define	SWAPSHORT(y) \
40 	( (((y)&0xff)<<8) | ((u_short)((y)&0xff00)>>8) )
41 
42 extern int dlt_to_linktype(int dlt);
43 
44 extern int linktype_to_dlt(int linktype);
45 
46 extern void swap_pseudo_headers(int linktype, struct pcap_pkthdr *hdr,
47     u_char *data);
48 
49 extern u_int max_snaplen_for_dlt(int dlt);
50