contrib/tcpdump/print-enc.c

   1 /*      $OpenBSD: print-enc.c,v 1.7 2002/02/19 19:39:40 millert Exp $   */
   2
   3 /*
   4  * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996
   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: OpenBSD IPsec encapsulation BPF layer printer */
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include <config.h>
  28 #endif
  29
  30 #include "netdissect-stdinc.h"
  31
  32 #define ND_LONGJMP_FROM_TCHECK
  33 #include "netdissect.h"
  34 #include "extract.h"
  35 #include "af.h"
  36
  37 /* From $OpenBSD: if_enc.h,v 1.8 2001/06/25 05:14:00 angelos Exp $ */
  38 /*
  39  * The authors of this code are John Ioannidis (ji@tla.org),
  40  * Angelos D. Keromytis (kermit@csd.uch.gr) and
  41  * Niels Provos (provos@physnet.uni-hamburg.de).
  42  *
  43  * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
  44  * in November 1995.
  45  *
  46  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
  47  * by Angelos D. Keromytis.
  48  *
  49  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
  50  * and Niels Provos.
  51  *
  52  * Copyright (C) 1995, 1996, 1997, 1998 by John Ioannidis, Angelos D. Keromytis
  53  * and Niels Provos.
  54  * Copyright (c) 2001, Angelos D. Keromytis.
  55  *
  56  * Permission to use, copy, and modify this software with or without fee
  57  * is hereby granted, provided that this entire notice is included in
  58  * all copies of any software which is or includes a copy or
  59  * modification of this software.
  60  * You may use this code under the GNU public license if you so wish. Please
  61  * contribute changes back to the authors under this freer than GPL license
  62  * so that we may further the use of strong encryption without limitations to
  63  * all.
  64  *
  65  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
  66  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
  67  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
  68  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
  69  * PURPOSE.
  70  */
  71
  72 #define ENC_HDRLEN      12
  73
  74 /* From $OpenBSD: mbuf.h,v 1.56 2002/01/25 15:50:23 art Exp $   */
  75 #define M_CONF          0x0400  /* packet was encrypted (ESP-transport) */
  76 #define M_AUTH          0x0800  /* packet was authenticated (AH) */
  77
  78 struct enchdr {
  79         nd_uint32_t af;
  80         nd_uint32_t spi;
  81         nd_uint32_t flags;
  82 };
  83
  84 #define ENC_PRINT_TYPE(wh, xf, name) \
  85         if ((wh) & (xf)) { \
  86                 ND_PRINT("%s%s", name, (wh) == (xf) ? "): " : ","); \
  87                 (wh) &= ~(xf); \
  88         }
  89
  90 /*
  91  * Byte-swap a 32-bit number.
  92  * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
  93  * big-endian platforms.)
  94  */
  95 #define SWAPLONG(y) \
  96 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
  97
  98 void
  99 enc_if_print(netdissect_options *ndo,
 100              const struct pcap_pkthdr *h, const u_char *p)
 101 {
 102         u_int length = h->len;
 103         u_int caplen = h->caplen;
 104         u_int af, flags;
 105         const struct enchdr *hdr;
 106
 107         ndo->ndo_protocol = "enc";
 108         ND_TCHECK_LEN(p, ENC_HDRLEN);
 109         ndo->ndo_ll_hdr_len += ENC_HDRLEN;
 110
 111         hdr = (const struct enchdr *)p;
 112         /*
 113          * The address family and flags fields are in the byte order
 114          * of the host that originally captured the traffic.
 115          *
 116          * To determine that, look at the address family.  It's 32-bit,
 117          * it is not likely ever to be > 65535 (I doubt there will
 118          * ever be > 65535 address families and, so far, AF_ values have
 119          * not been allocated very sparsely) so it should not have the
 120          * upper 16 bits set, and it is not likely ever to be AF_UNSPEC,
 121          * i.e. it's not likely ever to be 0, so if it's byte-swapped,
 122          * it should have at least one of the upper 16 bits set.
 123          *
 124          * So if any of the upper 16 bits are set, we assume it, and
 125          * the flags field, are byte-swapped.
 126          *
 127          * The SPI field is always in network byte order, i.e. big-
 128          * endian.
 129          */
 130         UNALIGNED_MEMCPY(&af, &hdr->af, sizeof (af));
 131         UNALIGNED_MEMCPY(&flags, &hdr->flags, sizeof (flags));
 132         if ((af & 0xFFFF0000) != 0) {
 133                 af = SWAPLONG(af);
 134                 flags = SWAPLONG(flags);
 135         }
 136
 137         if (flags == 0)
 138                 ND_PRINT("(unprotected): ");
 139         else
 140                 ND_PRINT("(");
 141         ENC_PRINT_TYPE(flags, M_AUTH, "authentic");
 142         ENC_PRINT_TYPE(flags, M_CONF, "confidential");
 143         /* ENC_PRINT_TYPE(flags, M_TUNNEL, "tunnel"); */
 144         ND_PRINT("SPI 0x%08x: ", GET_BE_U_4(hdr->spi));
 145
 146         length -= ENC_HDRLEN;
 147         caplen -= ENC_HDRLEN;
 148         p += ENC_HDRLEN;
 149
 150         switch (af) {
 151         case BSD_AFNUM_INET:
 152                 ip_print(ndo, p, length);
 153                 break;
 154         case BSD_AFNUM_INET6_BSD:
 155         case BSD_AFNUM_INET6_FREEBSD:
 156         case BSD_AFNUM_INET6_DARWIN:
 157                 ip6_print(ndo, p, length);
 158                 break;
 159         }
 160 }