epan/dissectors/packet-ipsec-udp.c

   1 /*
   2  * Copyright (c) 2003 Markus Friedl.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  15  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  16  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  17  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  18  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  19  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  20  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  21  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  22  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  23  *
  24  * $Id$
  25  */
  26 #include "config.h"
  27
  28 #include <glib.h>
  29 #include <epan/packet.h>
  30
  31 static int proto_udpencap = -1;
  32 static gint ett_udpencap = -1;
  33
  34 static dissector_handle_t esp_handle;
  35 static dissector_handle_t isakmp_handle;
  36
  37 /*
  38  * UDP Encapsulation of IPsec Packets
  39  * draft-ietf-ipsec-udp-encaps-06.txt
  40  */
  41 static void
  42 dissect_udpencap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  43 {
  44   tvbuff_t   *next_tvb;
  45   proto_tree *udpencap_tree = NULL;
  46   proto_item *ti            = NULL;
  47   guint32     spi;
  48
  49   col_set_str(pinfo->cinfo, COL_PROTOCOL, "UDPENCAP");
  50   col_clear(pinfo->cinfo, COL_INFO);
  51
  52   if (tree) {
  53     ti = proto_tree_add_item(tree, proto_udpencap, tvb, 0, -1, ENC_NA);
  54     udpencap_tree = proto_item_add_subtree(ti, ett_udpencap);
  55   }
  56
  57   /* 1 byte of 0xFF indicates NAT-keepalive */
  58   if ((tvb_length(tvb) == 1) && (tvb_get_guint8(tvb, 0) == 0xff)) {
  59     col_set_str(pinfo->cinfo, COL_INFO, "NAT-keepalive");
  60     if (tree)
  61       proto_tree_add_text(udpencap_tree, tvb, 0, 1, "NAT-keepalive packet");
  62   } else {
  63     /* SPI of zero indicates IKE traffic, otherwise it's ESP */
  64     tvb_memcpy(tvb, (guint8 *)&spi, 0, sizeof(spi));
  65     if (spi == 0) {
  66       col_set_str(pinfo->cinfo, COL_INFO, "ISAKMP");
  67       if (tree) {
  68         proto_tree_add_text(udpencap_tree, tvb, 0, sizeof(spi),
  69                 "Non-ESP Marker");
  70         proto_item_set_len(ti, sizeof(spi));
  71       }
  72       next_tvb = tvb_new_subset_remaining(tvb, sizeof(spi));
  73       call_dissector(isakmp_handle, next_tvb, pinfo, tree);
  74     } else {
  75       col_set_str(pinfo->cinfo, COL_INFO, "ESP");
  76       if (tree)
  77         proto_item_set_len(ti, 0);
  78       call_dissector(esp_handle, tvb, pinfo, tree);
  79     }
  80   }
  81 }
  82
  83 void
  84 proto_register_udpencap(void)
  85 {
  86   static gint *ett[] = {
  87     &ett_udpencap,
  88   };
  89
  90   proto_udpencap = proto_register_protocol(
  91         "UDP Encapsulation of IPsec Packets", "UDPENCAP", "udpencap");
  92   proto_register_subtree_array(ett, array_length(ett));
  93 }
  94
  95 void
  96 proto_reg_handoff_udpencap(void)
  97 {
  98   dissector_handle_t udpencap_handle;
  99
 100   esp_handle = find_dissector("esp");
 101   isakmp_handle = find_dissector("isakmp");
 102
 103   udpencap_handle = create_dissector_handle(dissect_udpencap, proto_udpencap);
 104   dissector_add_uint("udp.port", 4500, udpencap_handle);
 105 }