xref: /freebsd/contrib/libpcap/pcap-util.h (revision afdbf109c6a661a729938f68211054a0a50d38ac)
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-util.h - common code for various 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  * We also use this for fixing up packet data headers from a remote
35  * capture, where the server may have a different byte order from the
36  * client.
37  *
38  * ntoh[ls] aren't sufficient because we might need to swap on a big-endian
39  * machine (if the file was written in little-end order).
40  */
41 #define	SWAPLONG(y) \
42     (((((u_int)(y))&0xff)<<24) | \
43      ((((u_int)(y))&0xff00)<<8) | \
44      ((((u_int)(y))&0xff0000)>>8) | \
45      ((((u_int)(y))>>24)&0xff))
46 #define	SWAPSHORT(y) \
47      ((u_short)(((((u_int)(y))&0xff)<<8) | \
48                 ((((u_int)(y))&0xff00)>>8)))
49 
50 extern void pcapint_post_process(int linktype, int swapped,
51     struct pcap_pkthdr *hdr, u_char *data);
52