The Tcpdump Group git mirrors - libpcap/blob - pcap-util.h

   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 #ifndef pcap_util_h
  25 #define pcap_util_h
  26
  27 /*
  28  * We use the "receiver-makes-right" approach to byte order;
  29  * because time is at a premium when we are writing the file.
  30  * In other words, the pcap_file_header and pcap_pkthdr,
  31  * records are written in host byte order.
  32  * Note that the bytes of packet data are written out in the order in
  33  * which they were received, so multi-byte fields in packets are not
  34  * written in host byte order, they're written in whatever order the
  35  * sending machine put them in.
  36  *
  37  * We also use this for fixing up packet data headers from a remote
  38  * capture, where the server may have a different byte order from the
  39  * client.
  40  *
  41  * ntoh[ls] aren't sufficient because we might need to swap on a big-endian
  42  * machine (if the file was written in little-end order).
  43  */
  44 #define SWAPLONG(y) \
  45     (((((u_int)(y))&0xff)<<24) | \
  46      ((((u_int)(y))&0xff00)<<8) | \
  47      ((((u_int)(y))&0xff0000)>>8) | \
  48      ((((u_int)(y))>>24)&0xff))
  49 #define SWAPSHORT(y) \
  50      ((u_short)(((((u_int)(y))&0xff)<<8) | \
  51                 ((((u_int)(y))&0xff00)>>8)))
  52
  53 extern void pcapint_post_process(int linktype, int swapped,
  54     struct pcap_pkthdr *hdr, u_char *data);
  55
  56 #endif // pcap_util_h