epan/dissectors/packet-amt.c

   1 /* packet-amt.c
   2  * Routines for Automatic Multicast Tunneling (AMT) dissection
   3  * Copyright 2017, Alexis La Goutte (See AUTHORS)
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 /*
  13  * RFC 7450 : Automatic Multicast Tunneling
  14  */
  15
  16 #include <config.h>
  17 #include <epan/packet.h>
  18 #include <epan/expert.h>
  19 #include <epan/tfs.h>
  20
  21 #define AMT_UDP_PORT 2268
  22
  23 void proto_reg_handoff_amt(void);
  24 void proto_register_amt(void);
  25
  26 static dissector_handle_t amt_handle;
  27
  28 static int proto_amt;
  29 static int hf_amt_version;
  30 static int hf_amt_type;
  31 static int hf_amt_reserved;
  32 static int hf_amt_discovery_nonce;
  33 static int hf_amt_relay_address_ipv4;
  34 static int hf_amt_relay_address_ipv6;
  35 static int hf_amt_request_nonce;
  36 static int hf_amt_request_reserved;
  37 static int hf_amt_request_p;
  38 static int hf_amt_membership_query_reserved;
  39 static int hf_amt_membership_query_l;
  40 static int hf_amt_membership_query_g;
  41 static int hf_amt_response_mac;
  42 static int hf_amt_gateway_port_number;
  43 static int hf_amt_gateway_ip_address;
  44 static int hf_amt_multicast_data;
  45
  46 static expert_field ei_amt_relay_address_unknown;
  47 static expert_field ei_amt_unknown;
  48
  49 static int ett_amt;
  50
  51 #define RELAY_DISCOVERY         1
  52 #define RELAY_ADVERTISEMENT     2
  53 #define REQUEST                 3
  54 #define MEMBERSHIP_QUERY        4
  55 #define MEMBERSHIP_UPDATE       5
  56 #define MULTICAST_DATA          6
  57 #define TEARDOWN                7
  58
  59 static const value_string amt_type_vals[] = {
  60     { RELAY_DISCOVERY, "Relay Discovery" },
  61     { RELAY_ADVERTISEMENT, "Relay Advertisement" },
  62     { REQUEST, "Request" },
  63     { MEMBERSHIP_QUERY, "Membership Query" },
  64     { MEMBERSHIP_UPDATE, "Membership Update" },
  65     { MULTICAST_DATA, "Multicast Data" },
  66     { TEARDOWN, "Teardown" },
  67     {0, NULL }
  68 };
  69
  70 static const true_false_string tfs_request_p = {
  71     "IPv4 packet carrying an IGMPv3 General Query",
  72     "IPv6 packet carrying an MLDv2 General Query"
  73 };
  74
  75 static dissector_handle_t ip_handle;
  76
  77 /* Code to actually dissect the packets */
  78 static int
  79 dissect_amt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
  80 {
  81     proto_item *ti;
  82     proto_tree *amt_tree;
  83     unsigned    offset = 0;
  84     uint32_t    type;
  85     tvbuff_t   *next_tvb;
  86
  87     col_set_str(pinfo->cinfo, COL_PROTOCOL, "AMT");
  88
  89     ti = proto_tree_add_item(tree, proto_amt, tvb, 0, -1, ENC_NA);
  90
  91     amt_tree = proto_item_add_subtree(ti, ett_amt);
  92
  93     proto_tree_add_item(amt_tree, hf_amt_version, tvb, offset, 1, ENC_NA);
  94     proto_tree_add_item_ret_uint(amt_tree, hf_amt_type, tvb, offset, 1, ENC_NA, &type);
  95     col_set_str(pinfo->cinfo, COL_INFO, val_to_str_const(type, amt_type_vals, "Unknown AMT TYPE"));
  96     offset += 1;
  97
  98     switch(type){
  99         case RELAY_DISCOVERY: /* 1 */
 100             proto_tree_add_item(amt_tree, hf_amt_reserved, tvb, offset, 3, ENC_NA);
 101             offset += 3;
 102             proto_tree_add_item(amt_tree, hf_amt_discovery_nonce, tvb, offset, 4, ENC_NA);
 103             offset += 4;
 104         break;
 105         case RELAY_ADVERTISEMENT:{ /* 2 */
 106             uint32_t relay_length;
 107             proto_tree_add_item(amt_tree, hf_amt_reserved, tvb, offset, 3, ENC_NA);
 108             offset += 3;
 109             proto_tree_add_item(amt_tree, hf_amt_discovery_nonce, tvb, offset, 4, ENC_NA);
 110             offset += 4;
 111             relay_length = tvb_reported_length_remaining(tvb, offset);
 112             switch(relay_length){
 113                 case 4: /* IPv4 Address */
 114                     proto_tree_add_item(amt_tree, hf_amt_relay_address_ipv4, tvb, offset, 4, ENC_NA);
 115                     offset += 4;
 116                 break;
 117                 case 16: /* IPv6 Address */
 118                     proto_tree_add_item(amt_tree, hf_amt_relay_address_ipv6, tvb, offset, 16, ENC_NA);
 119                     offset += 16;
 120                 break;
 121                 default: /* Unknown type.. */
 122                     proto_tree_add_expert(amt_tree, pinfo, &ei_amt_relay_address_unknown, tvb, offset, relay_length);
 123                     offset += relay_length;
 124                 break;
 125             }
 126         }
 127         break;
 128         case REQUEST: /* 3 */
 129             proto_tree_add_item(amt_tree, hf_amt_request_reserved, tvb, offset, 1, ENC_NA);
 130             proto_tree_add_item(amt_tree, hf_amt_request_p, tvb, offset, 1, ENC_NA);
 131             offset += 1;
 132             proto_tree_add_item(amt_tree, hf_amt_reserved, tvb, offset, 2, ENC_NA);
 133             offset += 2;
 134             proto_tree_add_item(amt_tree, hf_amt_request_nonce, tvb, offset, 4, ENC_NA);
 135             offset += 4;
 136         break;
 137         case MEMBERSHIP_QUERY:{ /* 4 */
 138             uint32_t flags_g;
 139             proto_tree_add_item(amt_tree, hf_amt_membership_query_reserved, tvb, offset, 1, ENC_NA);
 140             proto_tree_add_item(amt_tree, hf_amt_membership_query_l, tvb, offset, 1, ENC_NA);
 141             proto_tree_add_item_ret_uint(amt_tree, hf_amt_membership_query_g, tvb, offset, 1, ENC_NA, &flags_g);
 142             offset += 1;
 143             proto_tree_add_item(amt_tree, hf_amt_response_mac, tvb, offset, 6, ENC_NA);
 144             offset += 6;
 145             proto_tree_add_item(amt_tree, hf_amt_request_nonce, tvb, offset, 4, ENC_NA);
 146             offset += 4;
 147             next_tvb = tvb_new_subset_remaining(tvb, offset);
 148             call_dissector(ip_handle, next_tvb, pinfo, amt_tree);
 149             offset += tvb_reported_length_remaining(tvb, offset);
 150             if(flags_g){
 151                 offset -= 2;
 152                 offset -= 16;
 153                 proto_tree_add_item(amt_tree, hf_amt_gateway_port_number, tvb, offset, 2, ENC_NA);
 154                 offset += 2;
 155                 proto_tree_add_item(amt_tree, hf_amt_gateway_ip_address, tvb, offset, 16, ENC_NA);
 156                 offset += 16;
 157             }
 158         }
 159         break;
 160         case MEMBERSHIP_UPDATE: /* 5 */
 161             proto_tree_add_item(amt_tree, hf_amt_reserved, tvb, offset, 1, ENC_NA);
 162             offset += 1;
 163             proto_tree_add_item(amt_tree, hf_amt_response_mac, tvb, offset, 6, ENC_NA);
 164             offset += 6;
 165             proto_tree_add_item(amt_tree, hf_amt_request_nonce, tvb, offset, 4, ENC_NA);
 166             offset += 4;
 167             next_tvb = tvb_new_subset_remaining(tvb, offset);
 168             call_dissector(ip_handle, next_tvb, pinfo, amt_tree);
 169             offset += tvb_reported_length_remaining(tvb, offset);
 170         break;
 171         case MULTICAST_DATA: /* 6 */
 172             proto_tree_add_item(amt_tree, hf_amt_reserved, tvb, offset, 1, ENC_NA);
 173             offset += 1;
 174             proto_tree_add_item(amt_tree, hf_amt_multicast_data, tvb, offset, -1, ENC_NA);
 175             next_tvb = tvb_new_subset_remaining(tvb, offset);
 176             call_dissector(ip_handle, next_tvb, pinfo, amt_tree);
 177             offset += tvb_reported_length_remaining(tvb, offset);
 178         break;
 179         case TEARDOWN:{ /* 7 */
 180             proto_tree_add_item(amt_tree, hf_amt_reserved, tvb, offset, 1, ENC_NA);
 181             offset += 1;
 182             proto_tree_add_item(amt_tree, hf_amt_response_mac, tvb, offset, 6, ENC_NA);
 183             offset += 6;
 184             proto_tree_add_item(amt_tree, hf_amt_request_nonce, tvb, offset, 4, ENC_NA);
 185             offset += 4;
 186             proto_tree_add_item(amt_tree, hf_amt_gateway_port_number, tvb, offset, 2, ENC_NA);
 187             offset += 2;
 188             proto_tree_add_item(amt_tree, hf_amt_gateway_ip_address, tvb, offset, 16, ENC_NA);
 189             offset += 16;
 190         }
 191         break;
 192         default:{
 193             uint32_t len_unknown;
 194             len_unknown = tvb_reported_length_remaining(tvb, offset);
 195             proto_tree_add_expert(amt_tree, pinfo, &ei_amt_unknown, tvb, offset, len_unknown);
 196             offset += len_unknown;
 197         }
 198         break;
 199     }
 200     return offset;
 201 }
 202
 203 void
 204 proto_register_amt(void)
 205 {
 206     expert_module_t *expert_amt;
 207
 208     static hf_register_info hf[] = {
 209         { &hf_amt_version,
 210           { "Version", "amt.version",
 211             FT_UINT8, BASE_DEC, NULL, 0xF0,
 212             "Must be always 0", HFILL }
 213         },
 214         { &hf_amt_type,
 215           { "Type", "amt.type",
 216             FT_UINT8, BASE_DEC, VALS(amt_type_vals), 0x0F,
 217             NULL, HFILL }
 218         },
 219         { &hf_amt_reserved,
 220           { "Reserved", "amt.reserved",
 221             FT_BYTES, BASE_NONE, NULL, 0x0,
 222             NULL, HFILL }
 223         },
 224         { &hf_amt_discovery_nonce,
 225           { "Discovery Nonce", "amt.discovery_nonce",
 226             FT_UINT32, BASE_HEX, NULL, 0x0,
 227             NULL, HFILL }
 228         },
 229         { &hf_amt_relay_address_ipv4,
 230           { "Relay Address (IPv4)", "amt.relay_address.ipv4",
 231             FT_IPv4, BASE_NONE, NULL, 0x0,
 232             NULL, HFILL }
 233         },
 234         { &hf_amt_relay_address_ipv6,
 235           { "Relay Address (IPv6)", "amt.relay_address.ipv6",
 236             FT_IPv6, BASE_NONE, NULL, 0x0,
 237             NULL, HFILL }
 238         },
 239         { &hf_amt_request_nonce,
 240           { "Request Nonce", "amt.request_nonce",
 241             FT_UINT32, BASE_HEX, NULL, 0x0,
 242             NULL, HFILL }
 243         },
 244         { &hf_amt_request_reserved,
 245           { "Reserved", "amt.request.reserved",
 246             FT_UINT8, BASE_HEX, NULL, 0xFE,
 247             NULL, HFILL }
 248         },
 249         { &hf_amt_request_p,
 250           { "P Flags", "amt.request.p",
 251             FT_BOOLEAN, 8, TFS(&tfs_request_p), 0x01,
 252             NULL, HFILL }
 253         },
 254         { &hf_amt_membership_query_reserved,
 255           { "Reserved", "amt.membership_query.reserved",
 256             FT_UINT8, BASE_HEX, NULL, 0xFC,
 257             NULL, HFILL }
 258         },
 259         { &hf_amt_membership_query_l,
 260           { "L Flags", "amt.membership_query.l",
 261             FT_UINT8, BASE_DEC, NULL, 0x02,
 262             NULL, HFILL }
 263         },
 264         { &hf_amt_membership_query_g,
 265           { "G Flags", "amt.membership_query.g",
 266             FT_UINT8, BASE_DEC, NULL, 0x01,
 267             NULL, HFILL }
 268         },
 269         { &hf_amt_response_mac,
 270           { "Response MAC", "amt.response_mac",
 271             FT_UINT48, BASE_HEX, NULL, 0x0,
 272             NULL, HFILL }
 273         },
 274         { &hf_amt_gateway_port_number,
 275           { "Gateway Port Number", "amt.gateway.port_number",
 276             FT_UINT16, BASE_DEC, NULL, 0x0,
 277             NULL, HFILL }
 278         },
 279         { &hf_amt_gateway_ip_address,
 280           { "Gateway IP Address", "amt.gateway.ip_address",
 281             FT_IPv6, BASE_NONE, NULL, 0x0,
 282             NULL, HFILL }
 283         },
 284         { &hf_amt_multicast_data,
 285           { "Multicast Data", "amt.multicast_data",
 286             FT_BYTES, BASE_NONE, NULL, 0x0,
 287             NULL, HFILL }
 288         },
 289     };
 290
 291     static int *ett[] = {
 292         &ett_amt
 293     };
 294
 295
 296     static ei_register_info ei[] = {
 297         { &ei_amt_relay_address_unknown,
 298           { "amt.relay_address.unknown", PI_UNDECODED, PI_NOTE,
 299             "Relay Address (Unknown Type)", EXPFILL }
 300         },
 301         { &ei_amt_unknown,
 302           { "amt.unknown", PI_UNDECODED, PI_NOTE,
 303             "Unknown Data", EXPFILL }
 304         }
 305     };
 306
 307
 308     proto_amt = proto_register_protocol("Automatic Multicast Tunneling", "AMT", "amt");
 309
 310     proto_register_field_array(proto_amt, hf, array_length(hf));
 311     proto_register_subtree_array(ett, array_length(ett));
 312
 313
 314     expert_amt = expert_register_protocol(proto_amt);
 315     expert_register_field_array(expert_amt, ei, array_length(ei));
 316
 317     amt_handle = register_dissector("amt", dissect_amt, proto_amt);
 318 }
 319
 320 void
 321 proto_reg_handoff_amt(void)
 322 {
 323     ip_handle = find_dissector_add_dependency("ip", proto_amt);
 324
 325     dissector_add_uint_with_preference("udp.port", AMT_UDP_PORT, amt_handle);
 326 }
 327
 328 /*
 329  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 330  *
 331  * Local variables:
 332  * c-basic-offset: 4
 333  * tab-width: 8
 334  * indent-tabs-mode: nil
 335  * End:
 336  *
 337  * vi: set shiftwidth=4 tabstop=8 expandtab:
 338  * :indentSize=4:tabSize=8:noTabs=true:
 339  */