epan/dissectors/packet-enc.c

   1 /* packet-enc.c
   2  *
   3  * Copyright (c) 2003 Markus Friedl.  All rights reserved.
   4  *
   5  * $Id$
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include "config.h"
  29
  30 #include <glib.h>
  31 #include <epan/packet.h>
  32 #include <epan/etypes.h>
  33 #include <epan/addr_resolv.h>
  34 #include <epan/aftypes.h>
  35 #include <wsutil/pint.h>
  36 #include "packet-enc.h"
  37 #include "packet-ip.h"
  38 #include "packet-ipv6.h"
  39
  40 #ifndef offsetof
  41 /* Can't trust stddef.h to be there for us */
  42 # define offsetof(type, member) ((size_t)(&((type *)0)->member))
  43 #endif
  44
  45 /* The header in OpenBSD Encapsulating Interface files. */
  46
  47 struct enchdr {
  48   guint32 af;
  49   guint32 spi;
  50   guint32 flags;
  51 };
  52 #define BSD_ENC_HDRLEN    sizeof(struct enchdr)
  53
  54 # define BSD_ENC_M_CONF          0x0400  /* payload encrypted */
  55 # define BSD_ENC_M_AUTH          0x0800  /* payload authenticated */
  56 # define BSD_ENC_M_COMP          0x1000  /* payload compressed */
  57 # define BSD_ENC_M_AUTH_AH       0x2000  /* header authenticated */
  58
  59 static dissector_handle_t  data_handle, ip_handle, ipv6_handle;
  60
  61 /* header fields */
  62 static int proto_enc = -1;
  63 static int hf_enc_af = -1;
  64 static int hf_enc_spi = -1;
  65 static int hf_enc_flags = -1;
  66
  67 static gint ett_enc = -1;
  68
  69 void
  70 capture_enc(const guchar *pd, int len, packet_counts *ld)
  71 {
  72   guint32 af;
  73
  74   if (!BYTES_ARE_IN_FRAME(0, len, (int)BSD_ENC_HDRLEN)) {
  75     ld->other++;
  76     return;
  77   }
  78
  79   af = pntohl(pd + offsetof(struct enchdr, af));
  80   switch (af) {
  81
  82   case BSD_AF_INET:
  83     capture_ip(pd, BSD_ENC_HDRLEN, len, ld);
  84     break;
  85
  86   case BSD_AF_INET6_BSD:
  87     capture_ipv6(pd, BSD_ENC_HDRLEN, len, ld);
  88     break;
  89
  90   default:
  91     ld->other++;
  92     break;
  93   }
  94 }
  95
  96 static const value_string af_vals[] = {
  97   { BSD_AF_INET,  "IPv4" },
  98   { BSD_AF_INET6_BSD, "IPv6" },
  99   { 0, NULL }
 100 };
 101
 102 static void
 103 dissect_enc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 104 {
 105   struct enchdr  ench;
 106   tvbuff_t      *next_tvb;
 107   proto_tree    *enc_tree;
 108   proto_item    *ti;
 109
 110   col_set_str(pinfo->cinfo, COL_PROTOCOL, "ENC");
 111
 112   /* Copy out the enc header to insure alignment */
 113   tvb_memcpy(tvb, (guint8 *)&ench, 0, sizeof(ench));
 114
 115   /* Byteswap the header now */
 116   ench.spi = g_ntohl(ench.spi);
 117   /* ench.af = g_ntohl(ench.af); */
 118   /* ench.flags = g_ntohl(ench.flags); */
 119
 120   if (tree) {
 121     ti = proto_tree_add_protocol_format(tree, proto_enc, tvb, 0,
 122                                         BSD_ENC_HDRLEN,
 123                                         "Enc %s, SPI 0x%8.8x, %s%s%s%s",
 124                                         val_to_str(ench.af, af_vals, "unknown (%u)"),
 125                                         ench.spi,
 126                                         ench.flags ? "" : "unprotected",
 127                                         ench.flags & BSD_ENC_M_AUTH ? "authentic" : "",
 128                                         (ench.flags & (BSD_ENC_M_AUTH|BSD_ENC_M_CONF)) ==
 129                                         (BSD_ENC_M_AUTH|BSD_ENC_M_CONF) ? ", " : "",
 130                                         ench.flags & BSD_ENC_M_CONF ? "confidential" : ""
 131       );
 132     enc_tree = proto_item_add_subtree(ti, ett_enc);
 133
 134     proto_tree_add_uint(enc_tree, hf_enc_af, tvb,
 135              offsetof(struct enchdr, af), sizeof(ench.af),
 136              ench.af);
 137     proto_tree_add_uint(enc_tree, hf_enc_spi, tvb,
 138              offsetof(struct enchdr, spi), sizeof(ench.spi),
 139              ench.spi);
 140     proto_tree_add_uint(enc_tree, hf_enc_flags, tvb,
 141              offsetof(struct enchdr, flags), sizeof(ench.flags),
 142              ench.flags);
 143   }
 144
 145   /* Set the tvbuff for the payload after the header */
 146   next_tvb = tvb_new_subset_remaining(tvb, BSD_ENC_HDRLEN);
 147
 148   switch (ench.af) {
 149
 150   case BSD_AF_INET:
 151     call_dissector(ip_handle, next_tvb, pinfo, tree);
 152     break;
 153
 154   case BSD_AF_INET6_BSD:
 155     call_dissector(ipv6_handle, next_tvb, pinfo, tree);
 156     break;
 157
 158   default:
 159     call_dissector(data_handle, next_tvb, pinfo, tree);
 160     break;
 161   }
 162 }
 163
 164 void
 165 proto_register_enc(void)
 166 {
 167   static hf_register_info hf[] = {
 168     { &hf_enc_af,
 169       { "Address Family", "enc.af", FT_UINT32, BASE_DEC, VALS(af_vals), 0x0,
 170         "Protocol (IPv4 vs IPv6)", HFILL }},
 171     { &hf_enc_spi,
 172       { "SPI", "enc.spi", FT_UINT32, BASE_HEX, NULL, 0x0,
 173         "Security Parameter Index", HFILL }},
 174     { &hf_enc_flags,
 175       { "Flags", "enc.flags", FT_UINT32, BASE_HEX, NULL, 0x0,
 176         "ENC flags", HFILL }},
 177   };
 178   static gint *ett[] = { &ett_enc };
 179
 180   proto_enc = proto_register_protocol("OpenBSD Encapsulating device",
 181                                       "ENC", "enc");
 182   proto_register_field_array(proto_enc, hf, array_length(hf));
 183   proto_register_subtree_array(ett, array_length(ett));
 184 }
 185
 186 void
 187 proto_reg_handoff_enc(void)
 188 {
 189   dissector_handle_t enc_handle;
 190
 191   ip_handle   = find_dissector("ip");
 192   ipv6_handle = find_dissector("ipv6");
 193   data_handle = find_dissector("data");
 194
 195   enc_handle  = create_dissector_handle(dissect_enc, proto_enc);
 196   dissector_add_uint("wtap_encap", WTAP_ENCAP_ENC, enc_handle);
 197 }