epan/dissectors/packet-ipsec-udp.c

   1 /*
   2  * Copyright (c) 2003 Markus Friedl.  All rights reserved.
   3  *
   4  * SPDX-License-Identifier: BSD-2-Clause
   5  */
   6
   7 #include "config.h"
   8
   9 #include <epan/packet.h>
  10
  11 void proto_register_udpencap(void);
  12 void proto_reg_handoff_udpencap(void);
  13
  14 #define UDPENCAP_PORT 4500
  15
  16 static int proto_udpencap;
  17
  18 static int hf_nat_keepalive;
  19 static int hf_non_esp_marker;
  20
  21 static int ett_udpencap;
  22
  23 static dissector_handle_t udpencap_handle;
  24 static dissector_handle_t esp_handle;
  25 static dissector_handle_t isakmp_handle;
  26
  27 /*
  28  * UDP Encapsulation of IPsec Packets
  29  * draft-ietf-ipsec-udp-encaps-06.txt
  30  */
  31 static int
  32 dissect_udpencap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  33 {
  34   tvbuff_t   *next_tvb;
  35   proto_tree *udpencap_tree;
  36   proto_item *ti;
  37   uint32_t    spi;
  38
  39   col_set_str(pinfo->cinfo, COL_PROTOCOL, "UDPENCAP");
  40   col_clear(pinfo->cinfo, COL_INFO);
  41
  42   ti = proto_tree_add_item(tree, proto_udpencap, tvb, 0, -1, ENC_NA);
  43   udpencap_tree = proto_item_add_subtree(ti, ett_udpencap);
  44
  45   /* 1 byte of 0xFF indicates NAT-keepalive */
  46   if ((tvb_captured_length(tvb) == 1) && (tvb_get_uint8(tvb, 0) == 0xff)) {
  47     col_set_str(pinfo->cinfo, COL_INFO, "NAT-keepalive");
  48     proto_tree_add_item(udpencap_tree, hf_nat_keepalive, tvb, 0, 1, ENC_NA);
  49   } else {
  50     /* SPI of zero indicates IKE traffic, otherwise it's ESP */
  51     spi = tvb_get_ntohl(tvb, 0);
  52     if (spi == 0) {
  53       col_set_str(pinfo->cinfo, COL_INFO, "ISAKMP");
  54       proto_tree_add_item(udpencap_tree, hf_non_esp_marker, tvb, 0, 4, ENC_NA);
  55       proto_item_set_len(ti, 4);
  56       next_tvb = tvb_new_subset_remaining(tvb, 4);
  57       call_dissector(isakmp_handle, next_tvb, pinfo, tree);
  58     } else {
  59       col_set_str(pinfo->cinfo, COL_INFO, "ESP");
  60       proto_item_set_len(ti, 0);
  61       call_dissector(esp_handle, tvb, pinfo, tree);
  62     }
  63   }
  64   return tvb_captured_length(tvb);
  65 }
  66
  67 void
  68 proto_register_udpencap(void)
  69 {
  70   static hf_register_info hf[] = {
  71     { &hf_nat_keepalive, { "NAT-keepalive packet", "udpencap.nat_keepalive",
  72           FT_NONE, BASE_NONE, NULL, 0, NULL, HFILL }},
  73     { &hf_non_esp_marker, { "Non-ESP Marker", "udpencap.non_esp_marker",
  74           FT_NONE, BASE_NONE, NULL, 0, NULL, HFILL }},
  75   };
  76
  77   static int *ett[] = {
  78     &ett_udpencap,
  79   };
  80
  81   proto_udpencap = proto_register_protocol("UDP Encapsulation of IPsec Packets", "UDPENCAP", "udpencap");
  82   proto_register_field_array(proto_udpencap, hf, array_length(hf));
  83   proto_register_subtree_array(ett, array_length(ett));
  84
  85   udpencap_handle = register_dissector("udpencap", dissect_udpencap, proto_udpencap);
  86 }
  87
  88 void
  89 proto_reg_handoff_udpencap(void)
  90 {
  91
  92   esp_handle = find_dissector_add_dependency("esp", proto_udpencap);
  93   isakmp_handle = find_dissector_add_dependency("isakmp", proto_udpencap);
  94
  95   dissector_add_uint_with_preference("udp.port", UDPENCAP_PORT, udpencap_handle);
  96 }
  97
  98 /*
  99  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 100  *
 101  * Local Variables:
 102  * c-basic-offset: 2
 103  * tab-width: 8
 104  * indent-tabs-mode: nil
 105  * End:
 106  *
 107  * ex: set shiftwidth=2 tabstop=8 expandtab:
 108  * :indentSize=2:tabSize=8:noTabs=true:
 109  */