The Tcpdump Group git mirrors - tcpdump/blob - print-ah.c

   1 /*      $NetBSD: print-ah.c,v 1.4 1996/05/20 00:41:16 fvdl Exp $        */
   2
   3 /*
   4  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
   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
  24 /* \summary: IPSEC Authentication Header printer */
  25
  26 #include <config.h>
  27
  28 #include "netdissect-stdinc.h"
  29
  30 #include "netdissect.h"
  31 #include "extract.h"
  32
  33 #include "ah.h"
  34
  35 int
  36 ah_print(netdissect_options *ndo, const u_char *bp)
  37 {
  38         const struct ah *ah;
  39         uint8_t ah_len;
  40         u_int ah_hdr_len;
  41         uint16_t reserved;
  42         const u_char *p;
  43
  44         ndo->ndo_protocol = "ah";
  45         ah = (const struct ah *)bp;
  46
  47         nd_print_protocol_caps(ndo);
  48 /*
  49  * RFC4302
  50  *
  51  * 2.2.  Payload Length
  52  *
  53  *    This 8-bit field specifies the length of AH in 32-bit words (4-byte
  54  *    units), minus "2".
  55  */
  56         ah_len = GET_U_1(ah->ah_len);
  57         ah_hdr_len = (ah_len + 2) * 4;
  58
  59         ND_PRINT("(");
  60         if (ndo->ndo_vflag)
  61                 ND_PRINT("length=%u(%u-bytes),", ah_len, ah_hdr_len);
  62         reserved = GET_BE_U_2(ah->ah_reserved);
  63         if (reserved)
  64                 ND_PRINT("reserved=0x%x[MustBeZero],", reserved);
  65         ND_PRINT("spi=0x%08x,", GET_BE_U_4(ah->ah_spi));
  66         ND_PRINT("seq=0x%x,", GET_BE_U_4(ah->ah_seq));
  67         ND_PRINT("icv=0x");
  68         for (p = (const u_char *)(ah + 1); p < bp + ah_hdr_len; p++)
  69                 ND_PRINT("%02x", GET_U_1(p));
  70         ND_PRINT("): ");
  71
  72         return ah_hdr_len;
  73 }