epan/dissectors/packet-pppoe.c

   1 /* packet-pppoe.c
   2  * Routines for PPP Over Ethernet (PPPoE) packet disassembly (RFC2516)
   3  * Up to date with http://www.iana.org/assignments/pppoe-parameters (2008-04-30)
   4  *
   5  * $Id$
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version 2
  14  * of the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  24  */
  25
  26 #ifdef HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include <glib.h>
  31 #include <epan/packet.h>
  32 #include <epan/strutil.h>
  33 #include <epan/etypes.h>
  34 #include <epan/prefs.h>
  35 #include <epan/expert.h>
  36
  37 static int proto_pppoed = -1;
  38
  39 /* Common to session and discovery protocols */
  40 static gint hf_pppoe_version = -1;
  41 static gint hf_pppoe_type = -1;
  42 static gint hf_pppoe_code = -1;
  43 static gint hf_pppoe_session_id = -1;
  44 static gint hf_pppoe_payload_length = -1;
  45
  46 /* Discovery protocol fields */
  47 static gint hf_pppoed_tags = -1;
  48 static gint hf_pppoed_tag = -1;
  49 static gint hf_pppoed_tag_length = -1;
  50 static gint hf_pppoed_tag_unknown_data = -1;
  51 static gint hf_pppoed_tag_service_name = -1;
  52 static gint hf_pppoed_tag_ac_name = -1;
  53 static gint hf_pppoed_tag_host_uniq = -1;
  54 static gint hf_pppoed_tag_ac_cookie = -1;
  55 static gint hf_pppoed_tag_vendor_id = -1;
  56 static gint hf_pppoed_tag_vendor_unspecified = -1;
  57 static gint hf_pppoed_tag_credits = -1;
  58 static gint hf_pppoed_tag_credits_fcn = -1;
  59 static gint hf_pppoed_tag_credits_bcn = -1;
  60 static gint hf_pppoed_tag_metrics = -1;
  61 static gint hf_pppoed_tag_metrics_r = -1;
  62 static gint hf_pppoed_tag_metrics_rlq = -1;
  63 static gint hf_pppoed_tag_metrics_resource = -1;
  64 static gint hf_pppoed_tag_metrics_latency = -1;
  65 static gint hf_pppoed_tag_metrics_curr_drate = -1;
  66 static gint hf_pppoed_tag_metrics_max_drate = -1;
  67 static gint hf_pppoed_tag_mdr_units = -1;
  68 static gint hf_pppoed_tag_cdr_units = -1;
  69 static gint hf_pppoed_tag_seq_num = -1;
  70 static gint hf_pppoed_tag_cred_scale = -1;
  71 static gint hf_pppoed_tag_relay_session_id = -1;
  72 static gint hf_pppoed_tag_hurl = -1;
  73 static gint hf_pppoed_tag_motm = -1;
  74 static gint hf_pppoed_tag_max_payload = -1;
  75 static gint hf_pppoed_tag_ip_route_add = -1;
  76 static gint hf_pppoed_tag_service_name_error = -1;
  77 static gint hf_pppoed_tag_ac_system_error = -1;
  78 static gint hf_pppoed_tag_generic_error = -1;
  79
  80 /* Session protocol fields */
  81 static gint hf_pppoes_tags = -1;
  82 static gint hf_pppoes_tag = -1;
  83 static gint hf_pppoes_tag_credits = -1;
  84 static gint hf_pppoes_tag_credits_fcn = -1;
  85 static gint hf_pppoes_tag_credits_bcn = -1;
  86
  87 /* Session protocol fields */
  88
  89 static gint ett_pppoed = -1;
  90 static gint ett_pppoed_tags = -1;
  91
  92 static int proto_pppoes = -1;
  93
  94 static gint ett_pppoes = -1;
  95 static gint ett_pppoes_tags = -1;
  96
  97 /* PPPoE parent fields */
  98
  99 static int proto_pppoe = -1;
 100 static gint ett_pppoe = -1;
 101
 102
 103 /* Handle for calling for ppp dissector to handle session data */
 104 static dissector_handle_t ppp_handle;
 105
 106
 107 /* Preference for showing discovery tag values and lengths */
 108 static gboolean global_pppoe_show_tags_and_lengths = FALSE;
 109
 110
 111 #define PPPOE_CODE_SESSION    0x00
 112 #define PPPOE_CODE_PADO       0x07
 113 #define PPPOE_CODE_PADI       0x09
 114 #define PPPOE_CODE_PADG       0x0a
 115 #define PPPOE_CODE_PADC       0x0b
 116 #define PPPOE_CODE_PADQ       0x0c
 117 #define PPPOE_CODE_PADR       0x19
 118 #define PPPOE_CODE_PADS       0x65
 119 #define PPPOE_CODE_PADT       0xa7
 120 #define PPPOE_CODE_PADM       0xd3
 121 #define PPPOE_CODE_PADN       0xd4
 122
 123 #define PPPOE_TAG_EOL         0x0000
 124 #define PPPOE_TAG_SVC_NAME    0x0101
 125 #define PPPOE_TAG_AC_NAME     0x0102
 126 #define PPPOE_TAG_HOST_UNIQ   0x0103
 127 #define PPPOE_TAG_AC_COOKIE   0x0104
 128 #define PPPOE_TAG_VENDOR      0x0105
 129 #define PPPOE_TAG_CREDITS     0x0106
 130 #define PPPOE_TAG_METRICS     0x0107
 131 #define PPPOE_TAG_SEQ_NUM     0x0108
 132 #define PPPOE_TAG_CRED_SCALE  0x0109
 133 #define PPPOE_TAG_RELAY_ID    0x0110
 134 #define PPPOE_TAG_HURL        0x0111
 135 #define PPPOE_TAG_MOTM        0x0112
 136 #define PPPOE_TAG_MAX_PAYLD   0x0120
 137 #define PPPOE_TAG_IP_RT_ADD   0x0121
 138 #define PPPOE_TAG_SVC_ERR     0x0201
 139 #define PPPOE_TAG_AC_ERR      0x0202
 140 #define PPPOE_TAG_GENERIC_ERR 0x0203
 141
 142 #define PPPOE_CDR_MASK        0x06
 143 #define PPPOE_MDR_MASK        0x18
 144 #define PPPOE_RCV_ONLY_MASK   0x01
 145
 146 #define PPPOE_SCALE_KBPS      0x00
 147 #define PPPOE_SCALE_MBPS      0x01
 148 #define PPPOE_SCALE_GBPS      0x02
 149 #define PPPOE_SCALE_TBPS      0x03
 150
 151
 152 static const value_string code_vals[] = {
 153                 {PPPOE_CODE_SESSION, "Session Data"                             },
 154                 {PPPOE_CODE_PADO, "Active Discovery Offer (PADO)"               },
 155                 {PPPOE_CODE_PADI, "Active Discovery Initiation (PADI)"          },
 156                 {PPPOE_CODE_PADG, "Active Discovery Session-Grant (PADG)"       },
 157                 {PPPOE_CODE_PADC, "Active Discovery Session-Credit Resp.(PADC)" },
 158                 {PPPOE_CODE_PADQ, "Active Discovery Quality (PADQ)"             },
 159                 {PPPOE_CODE_PADR, "Active Discovery Request (PADR)"             },
 160                 {PPPOE_CODE_PADS, "Active Discovery Session-confirmation (PADS)"},
 161                 {PPPOE_CODE_PADT, "Active Discovery Terminate (PADT)"           },
 162                 {PPPOE_CODE_PADM, "Active Discovery Message (PADM)"             },
 163                 {PPPOE_CODE_PADN, "Active Discovery Network (PADN)"             },
 164                 {0,               NULL                                          }
 165 };
 166
 167
 168 static const value_string tag_vals[] = {
 169                 {PPPOE_TAG_EOL,        "End-Of-List"       },
 170                 {PPPOE_TAG_SVC_NAME,   "Service-Name"      },
 171                 {PPPOE_TAG_AC_NAME,    "AC-Name"           },
 172                 {PPPOE_TAG_HOST_UNIQ,  "Host-Uniq"         },
 173                 {PPPOE_TAG_AC_COOKIE,  "AC-Cookie"         },
 174                 {PPPOE_TAG_VENDOR,     "Vendor-Specific"   },
 175                 {PPPOE_TAG_CREDITS,    "Credits"           },
 176                 {PPPOE_TAG_METRICS,    "Metrics"           },
 177                 {PPPOE_TAG_SEQ_NUM,    "Sequence Number"    },
 178                 {PPPOE_TAG_CRED_SCALE, "Credit Scale Factor"},
 179                 {PPPOE_TAG_RELAY_ID,   "Relay-Session-Id"  },
 180                 {PPPOE_TAG_HURL,       "HURL"              },
 181                 {PPPOE_TAG_MOTM,       "MOTM"              },
 182                 {PPPOE_TAG_MAX_PAYLD,  "PPP-Max-Payload"   },
 183                 {PPPOE_TAG_IP_RT_ADD,  "IP Route Add"      },
 184                 {PPPOE_TAG_SVC_ERR,    "Service-Name-Error"},
 185                 {PPPOE_TAG_AC_ERR,     "AC-System-Error"   },
 186                 {PPPOE_TAG_GENERIC_ERR,"Generic-Error"     },
 187                 {0,                    NULL                }
 188 };
 189
 190 const value_string datarate_scale_vals[] = {
 191                 {PPPOE_SCALE_KBPS,      "kilobits per second"},
 192                 {PPPOE_SCALE_MBPS,      "megabits per second"},
 193                 {PPPOE_SCALE_GBPS,      "gigabits per second"},
 194                 {PPPOE_SCALE_TBPS,      "terabits per second"},
 195                 {0,                     NULL                 }
 196 };
 197
 198
 199 /* Dissect discovery protocol tags */
 200 static void
 201 dissect_pppoe_tags(tvbuff_t *tvb, packet_info *pinfo, int offset, proto_tree *tree,
 202                    int payload_length)
 203 {
 204         guint16 poe_tag;
 205         guint16 poe_tag_length;
 206         int tagstart;
 207         guint16 poe_rsv = 0;
 208
 209         proto_tree  *pppoe_tree;
 210         proto_item  *ti;
 211         proto_item  *pppoe_tree_tag_length_item = NULL;
 212         proto_item  *item;
 213
 214         /* Start Decoding Here. */
 215         if (tree)
 216         {
 217                 /* Create tags subtree */
 218                 ti = proto_tree_add_item(tree, hf_pppoed_tags, tvb, offset, payload_length-6, FALSE);
 219                 pppoe_tree = proto_item_add_subtree(ti, ett_pppoed_tags);
 220
 221                 tagstart = offset;
 222
 223                 /* Loop until all data seen or End-Of-List tag found */
 224                 while (tagstart <= payload_length-2)
 225                 {
 226                         poe_tag = tvb_get_ntohs(tvb, tagstart);
 227                         poe_tag_length = tvb_get_ntohs(tvb, tagstart + 2);
 228
 229                         /* Tag value and data length */
 230                         if (global_pppoe_show_tags_and_lengths)
 231                         {
 232                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag, tvb, tagstart, 2, FALSE);
 233                                 pppoe_tree_tag_length_item =
 234                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_length, tvb, tagstart+2, 2, FALSE);
 235                         }
 236
 237                         /* Show tag data */
 238                         switch (poe_tag)
 239                         {
 240                                 case PPPOE_TAG_SVC_NAME:
 241                                         if (poe_tag_length > 0)
 242                                         {
 243                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_service_name, tvb,
 244                                                                     tagstart+4, poe_tag_length, FALSE);
 245                                         }
 246                                         break;
 247                                 case PPPOE_TAG_AC_NAME:
 248                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_ac_name, tvb,
 249                                                             tagstart+4, poe_tag_length, FALSE);
 250                                         /* Show AC-Name in info column */
 251                                         if (check_col(pinfo->cinfo, COL_INFO))
 252                                         {
 253                                                 col_append_fstr(pinfo->cinfo, COL_INFO, " AC-Name='%s'",
 254                                                                tvb_get_ephemeral_string(tvb, tagstart+4, poe_tag_length));
 255                                         }
 256                                         break;
 257                                 case PPPOE_TAG_HOST_UNIQ:
 258                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_host_uniq, tvb,
 259                                                             tagstart+4, poe_tag_length, FALSE);
 260                                         break;
 261                                 case PPPOE_TAG_AC_COOKIE:
 262                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_ac_cookie, tvb,
 263                                                             tagstart+4, poe_tag_length, FALSE);
 264                                         break;
 265                                 case PPPOE_TAG_VENDOR:
 266                                         if (poe_tag_length >= 4)
 267                                         {
 268                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_vendor_id, tvb,
 269                                                                                         tagstart+4, 4, FALSE);
 270                                         }
 271                                         if (poe_tag_length > 4)
 272                                         {
 273                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_vendor_unspecified, tvb,
 274                                                                     tagstart+4+4, poe_tag_length-4, FALSE);
 275                                         }
 276                                         break;
 277                                 case PPPOE_TAG_CREDITS:
 278                                         if (poe_tag_length == 4)
 279                                         {
 280                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_credits_fcn, tvb,
 281                                                                     tagstart+4, 2, FALSE);
 282                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_credits_bcn, tvb,
 283                                                                     tagstart+6, 2, FALSE);
 284                                         } else {
 285                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_credits, tvb,
 286                                                                     tagstart+4, poe_tag_length, FALSE);
 287                                         }
 288                                         break;
 289                                 case PPPOE_TAG_METRICS:
 290                                         if (poe_tag_length == 10)
 291                                         {
 292                                                 poe_rsv = tvb_get_ntohs(tvb, tagstart+4);
 293
 294                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_mdr_units, tvb,
 295                                                                     tagstart+4, 2, FALSE);
 296                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_cdr_units, tvb,
 297                                                                     tagstart+4, 2, FALSE);
 298                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_r, tvb,
 299                                                                     tagstart+4, 2, FALSE);
 300                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_rlq, tvb,
 301                                                                     tagstart+6, 1, FALSE);
 302                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_resource, tvb,
 303                                                                     tagstart+7, 1, FALSE);
 304                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_latency, tvb,
 305                                                                     tagstart+8, 2, FALSE);
 306
 307                                                 /* CDR */
 308                                                 ti = proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_curr_drate, tvb,
 309                                                                          tagstart+10, 2, FALSE);
 310
 311                                                 switch ((poe_rsv & PPPOE_CDR_MASK) >> 1)
 312                                                 {
 313                                                 case (PPPOE_SCALE_KBPS):
 314                                                     proto_item_append_text(ti, " kbps");
 315                                                     break;
 316                                                 case (PPPOE_SCALE_MBPS):
 317                                                     proto_item_append_text(ti, " mbps");
 318                                                     break;
 319                                                 case (PPPOE_SCALE_GBPS):
 320                                                     proto_item_append_text(ti, " gbps");
 321                                                     break;
 322                                                 case (PPPOE_SCALE_TBPS):
 323                                                     proto_item_append_text(ti, " tbps");
 324                                                     break;
 325                                                 }
 326
 327                                                 /* MDR */
 328                                                 ti = proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_max_drate, tvb,
 329                                                                     tagstart+12, 2, FALSE);
 330
 331                                                 switch ((poe_rsv & PPPOE_MDR_MASK) >> 3)
 332                                                 {
 333                                                 case (PPPOE_SCALE_KBPS):
 334                                                     proto_item_append_text(ti, " kbps");
 335                                                     break;
 336                                                 case (PPPOE_SCALE_MBPS):
 337                                                     proto_item_append_text(ti, " mbps");
 338                                                     break;
 339                                                 case (PPPOE_SCALE_GBPS):
 340                                                     proto_item_append_text(ti, " gbps");
 341                                                     break;
 342                                                 case (PPPOE_SCALE_TBPS):
 343                                                     proto_item_append_text(ti, " tbps");
 344                                                     break;
 345                                                 }
 346
 347                                         } else {
 348                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics, tvb,
 349                                                                     tagstart+4, poe_tag_length, FALSE);
 350                                         }
 351                                         break;
 352                                 case PPPOE_TAG_SEQ_NUM:
 353                                         if (poe_tag_length == 2) {
 354                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_seq_num, tvb,
 355                                                                     tagstart+4, poe_tag_length, FALSE);
 356                                         } else {
 357                                                 if (global_pppoe_show_tags_and_lengths) {
 358                                                         proto_item_append_text(pppoe_tree_tag_length_item, " [Wrong: should be 2]");
 359                                                         item = pppoe_tree_tag_length_item;
 360                                                 } else {
 361                                                         item = proto_tree_add_text(pppoe_tree, tvb, tagstart+4, poe_tag_length,
 362                                                             "%s: Wrong length: %u (expected 2)",
 363                                                             proto_registrar_get_name(hf_pppoed_tag_seq_num),
 364                                                             poe_tag_length);
 365                                                 }
 366                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_WARN,
 367                                                                        "Sequence Number tag: Wrong length: %u (expected 2)",
 368                                                                        poe_tag_length);
 369                                         }
 370                                         break;
 371                                 case PPPOE_TAG_CRED_SCALE:
 372                                         if (poe_tag_length == 2) {
 373                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_cred_scale, tvb,
 374                                                                     tagstart+4, poe_tag_length, FALSE);
 375                                         } else {
 376                                                 if (global_pppoe_show_tags_and_lengths) {
 377                                                         proto_item_append_text(pppoe_tree_tag_length_item, " [Wrong: should be 2]");
 378                                                         item = pppoe_tree_tag_length_item;
 379                                                 } else {
 380                                                         item = proto_tree_add_text(pppoe_tree, tvb, tagstart+4, poe_tag_length,
 381                                                             "%s: Wrong length: %u (expected 2)",
 382                                                             proto_registrar_get_name(hf_pppoed_tag_cred_scale),
 383                                                             poe_tag_length);
 384                                                 }
 385                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_WARN,
 386                                                                        "Credit Scale Factor tag: Wrong length: %u (expected 2)",
 387                                                                        poe_tag_length);
 388                                         }
 389                                         break;
 390                                 case PPPOE_TAG_RELAY_ID:
 391                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_relay_session_id, tvb,
 392                                                             tagstart+4, poe_tag_length, FALSE);
 393                                         break;
 394                                 case PPPOE_TAG_HURL:
 395                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_hurl, tvb,
 396                                                             tagstart+4, poe_tag_length, FALSE);
 397                                         break;
 398                                 case PPPOE_TAG_MOTM:
 399                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_motm, tvb,
 400                                                             tagstart+4, poe_tag_length, FALSE);
 401                                         break;
 402                                 case PPPOE_TAG_MAX_PAYLD:
 403                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_max_payload, tvb,
 404                                                             tagstart+4, poe_tag_length, FALSE);
 405                                         break;
 406                                 case PPPOE_TAG_IP_RT_ADD:
 407                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_ip_route_add, tvb,
 408                                                             tagstart+4, poe_tag_length, FALSE);
 409                                         break;
 410
 411                                 /* These error tag values should be interpreted as a utf-8 unterminated
 412                                    strings. */
 413                                 case PPPOE_TAG_SVC_ERR:
 414                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_service_name_error, tvb,
 415                                                             tagstart+4, poe_tag_length, FALSE);
 416                                         break;
 417                                 case PPPOE_TAG_AC_ERR:
 418                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_ac_system_error, tvb,
 419                                                             tagstart+4, poe_tag_length, FALSE);
 420                                         break;
 421                                 case PPPOE_TAG_GENERIC_ERR:
 422                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_generic_error, tvb,
 423                                                             tagstart+4, poe_tag_length, FALSE);
 424                                         break;
 425
 426                                 /* Get out if see end-of-list tag */
 427                                 case PPPOE_TAG_EOL:
 428                                         return;
 429
 430                                 default:
 431                                         if (poe_tag_length > 0 )
 432                                         {
 433                                                 /* Presumably unknown tag;
 434                                                    show tag value if we didn't
 435                                                    do it above */
 436                                                 if (!global_pppoe_show_tags_and_lengths)
 437                                                 {
 438                                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag, tvb, tagstart, 2, FALSE);
 439                                                         proto_tree_add_item(pppoe_tree, hf_pppoed_tag_length, tvb, tagstart+2, 2, FALSE);
 440                                                 }
 441                                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_unknown_data, tvb,
 442                                                                     tagstart+4, poe_tag_length, FALSE);
 443                                         }
 444                         }
 445
 446                         tagstart += (4 + poe_tag_length);
 447                 }
 448         }
 449 }
 450
 451
 452 /* Discovery protocol, i.e. PPP session not yet established */
 453 static void dissect_pppoed(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 454 {
 455         guint8  pppoe_code;
 456         guint16 reported_payload_length;
 457
 458         proto_tree  *pppoe_tree = NULL;
 459         proto_item  *ti;
 460
 461         col_set_str(pinfo->cinfo, COL_PROTOCOL, "PPPoED");
 462         col_clear(pinfo->cinfo, COL_INFO);
 463
 464         /* Start Decoding Here. */
 465         pppoe_code = tvb_get_guint8(tvb, 1);
 466
 467         if (check_col(pinfo->cinfo, COL_INFO))
 468         {
 469                 col_append_str(pinfo->cinfo, COL_INFO, val_to_str(pppoe_code, code_vals, "Unknown"));
 470         }
 471
 472         /* Read length of payload */
 473         reported_payload_length = tvb_get_ntohs(tvb, 4);
 474
 475         if (tree)
 476         {
 477                 ti = proto_tree_add_item(tree, proto_pppoed, tvb, 0, reported_payload_length+6, FALSE);
 478                 pppoe_tree = proto_item_add_subtree(ti, ett_pppoed);
 479
 480                 /* Dissect fixed fields */
 481                 proto_tree_add_item(pppoe_tree, hf_pppoe_version, tvb, 0, 1, FALSE);
 482                 proto_tree_add_item(pppoe_tree, hf_pppoe_type, tvb, 0, 1, FALSE);
 483                 proto_tree_add_item(pppoe_tree, hf_pppoe_code, tvb, 1, 1, FALSE);
 484                 proto_tree_add_item(pppoe_tree, hf_pppoe_session_id, tvb, 2, 2, FALSE);
 485                 proto_tree_add_item(pppoe_tree, hf_pppoe_payload_length, tvb, 4, 2, FALSE);
 486         }
 487
 488         /* Now dissect any tags */
 489         if (reported_payload_length > 0)
 490         {
 491                 dissect_pppoe_tags(tvb, pinfo, 6, pppoe_tree, 6+reported_payload_length);
 492         }
 493
 494 }
 495
 496 void proto_register_pppoed(void)
 497 {
 498         static hf_register_info hf[] =
 499         {
 500                 /* Discovery tag fields */
 501                 { &hf_pppoed_tags,
 502                         { "PPPoE Tags", "pppoed.tags", FT_NONE, BASE_NONE,
 503                                  NULL, 0x0, NULL, HFILL
 504                         }
 505                 },
 506                 { &hf_pppoed_tag,
 507                         { "Tag", "pppoed.tag", FT_UINT16, BASE_HEX,
 508                                  VALS(tag_vals), 0x0, NULL, HFILL
 509                         }
 510                 },
 511                 { &hf_pppoed_tag_length,
 512                         { "Tag Length", "pppoed.tag_length", FT_UINT16, BASE_DEC,
 513                                  NULL, 0x0, NULL, HFILL
 514                         }
 515                 },
 516                 { &hf_pppoed_tag_unknown_data,
 517                         { "Unknown Data", "pppoed.tag.unknown_data", FT_BYTES, BASE_NONE,
 518                                  NULL, 0x0, NULL, HFILL
 519                         }
 520                 },
 521                 { &hf_pppoed_tag_service_name,
 522                         { "Service-Name", "pppoed.tags.service_name", FT_STRING, BASE_NONE,
 523                                  NULL, 0x0, NULL, HFILL
 524                         }
 525                 },
 526                 { &hf_pppoed_tag_ac_name,
 527                         { "AC-Name", "pppoed.tags.ac_name", FT_STRING, BASE_NONE,
 528                                  NULL, 0x0, NULL, HFILL
 529                         }
 530                 },
 531                 { &hf_pppoed_tag_host_uniq,
 532                         { "Host-Uniq", "pppoed.tags.host_uniq", FT_BYTES, BASE_NONE,
 533                                  NULL, 0x0, NULL, HFILL
 534                         }
 535                 },
 536                 { &hf_pppoed_tag_ac_cookie,
 537                         { "AC-Cookie", "pppoed.tags.ac_cookie", FT_BYTES, BASE_NONE,
 538                                  NULL, 0x0, NULL, HFILL
 539                         }
 540                 },
 541                 { &hf_pppoed_tag_vendor_id,
 542                         { "Vendor id", "pppoed.tags.vendor_id", FT_UINT32, BASE_HEX,
 543                                  NULL, 0x0, NULL, HFILL
 544                         }
 545                 },
 546                 { &hf_pppoed_tag_vendor_unspecified,
 547                         { "Vendor unspecified", "pppoed.tags.vendor_unspecified", FT_BYTES, BASE_NONE,
 548                                  NULL, 0x0, NULL, HFILL
 549                         }
 550                 },
 551                 { &hf_pppoed_tag_credits,
 552                         { "Credits", "pppoed.tags.credits", FT_BYTES, BASE_NONE,
 553                                  NULL, 0x0, NULL, HFILL
 554                         }
 555                 },
 556                 { &hf_pppoed_tag_credits_fcn,
 557                         { "FCN", "pppoed.tags.credits.fcn", FT_UINT16, BASE_DEC,
 558                                  NULL, 0x0, NULL, HFILL
 559                         }
 560                 },
 561                 { &hf_pppoed_tag_credits_bcn,
 562                         { "BCN", "pppoed.tags.credits.bcn", FT_UINT16, BASE_DEC,
 563                                  NULL, 0x0, NULL, HFILL
 564                         }
 565                 },
 566                 { &hf_pppoed_tag_metrics,
 567                         { "Metrics", "pppoed.tags.metrics", FT_BYTES, BASE_NONE,
 568                                  NULL, 0x0, NULL, HFILL
 569                         }
 570                 },
 571                 { &hf_pppoed_tag_metrics_r,
 572                         { "Receive Only", "pppoed.tags.metrics.r", FT_BOOLEAN, 16,
 573                                  NULL, PPPOE_RCV_ONLY_MASK, NULL, HFILL
 574                         }
 575                 },
 576                 { &hf_pppoed_tag_mdr_units,
 577                         { "MDR Units", "pppoed.tags.metrics.mdr_units", FT_UINT16, BASE_HEX,
 578                                  VALS(datarate_scale_vals), PPPOE_MDR_MASK, NULL, HFILL
 579                         }
 580                 },
 581                 { &hf_pppoed_tag_cdr_units,
 582                         { "CDR Units", "pppoed.tags.metrics.cdr_units", FT_UINT16, BASE_HEX,
 583                                  VALS(datarate_scale_vals), PPPOE_CDR_MASK, NULL, HFILL
 584                         }
 585                 },
 586                 { &hf_pppoed_tag_metrics_rlq,
 587                         { "Relative Link Quality", "pppoed.tags.metrics.rlq", FT_UINT8, BASE_DEC,
 588                                  NULL, 0x0, NULL, HFILL
 589                         }
 590                 },
 591                 { &hf_pppoed_tag_metrics_resource,
 592                         { "Resource", "pppoed.tags.metrics.resource", FT_UINT8, BASE_DEC,
 593                                  NULL, 0x0, NULL, HFILL
 594                         }
 595                 },
 596                 { &hf_pppoed_tag_metrics_latency,
 597                         { "Latency", "pppoed.tags.metrics.latency", FT_UINT16, BASE_DEC,
 598                                  NULL, 0x0, NULL, HFILL
 599                         }
 600                 },
 601                 { &hf_pppoed_tag_metrics_curr_drate,
 602                         { "Curr. datarate", "pppoed.tags.metrics.curr_drate", FT_UINT16, BASE_DEC,
 603                                  NULL, 0x0, NULL, HFILL
 604                         }
 605                 },
 606                 { &hf_pppoed_tag_metrics_max_drate,
 607                         { "Max. datarate", "pppoed.tags.metrics.max_drate", FT_UINT16, BASE_DEC,
 608                                  NULL, 0x0, NULL, HFILL
 609                         }
 610                 },
 611                 { &hf_pppoed_tag_seq_num,
 612                         { "Sequence Number", "pppoed.tags.seq_num", FT_UINT16, BASE_HEX,
 613                                  NULL, 0x0, NULL, HFILL
 614                         }
 615                 },
 616                 { &hf_pppoed_tag_cred_scale,
 617                         { "Credit Scale Factor", "pppoed.tags.credit_scale", FT_UINT16, BASE_DEC,
 618                                  NULL, 0x0, NULL, HFILL
 619                         }
 620                 },
 621                 { &hf_pppoed_tag_relay_session_id,
 622                         { "Relay-Session-Id", "pppoed.tags.relay_session_id", FT_BYTES, BASE_NONE,
 623                                  NULL, 0x0, NULL, HFILL
 624                         }
 625                 },
 626                 { &hf_pppoed_tag_hurl,
 627                         { "HURL", "pppoed.tags.hurl", FT_BYTES, BASE_NONE,
 628                                  NULL, 0x0, NULL, HFILL
 629                         }
 630                 },
 631                 { &hf_pppoed_tag_motm,
 632                         { "MOTM", "pppoed.tags.motm", FT_BYTES, BASE_NONE,
 633                                  NULL, 0x0, NULL, HFILL
 634                         }
 635                 },
 636                 { &hf_pppoed_tag_max_payload,
 637                         { "PPP Max Palyload", "pppoed.tags.max_payload", FT_BYTES, BASE_NONE,
 638                                  NULL, 0x0, NULL, HFILL
 639                         }
 640                 },
 641                 { &hf_pppoed_tag_ip_route_add,
 642                         { "IP Route Add", "pppoed.tags.ip_route_add", FT_BYTES, BASE_NONE,
 643                                  NULL, 0x0, NULL, HFILL
 644                         }
 645                 },
 646                 { &hf_pppoed_tag_service_name_error,
 647                         { "Service-Name-Error", "pppoed.tags.service_name_error", FT_STRING, BASE_NONE,
 648                                  NULL, 0x0, NULL, HFILL
 649                         }
 650                 },
 651                 { &hf_pppoed_tag_ac_system_error,
 652                         { "AC-System-Error", "pppoed.tags.ac_system_error", FT_STRING, BASE_NONE,
 653                                  NULL, 0x0, NULL, HFILL
 654                         }
 655                 },
 656                 { &hf_pppoed_tag_generic_error,
 657                         { "Generic-Error", "pppoed.tags.generic_error", FT_STRING, BASE_NONE,
 658                                  NULL, 0x0, NULL, HFILL
 659                         }
 660                 }
 661         };
 662
 663         static gint *ett[] = {
 664                 &ett_pppoed,
 665                 &ett_pppoed_tags
 666         };
 667
 668         module_t *pppoed_module;
 669
 670         /* Register protocol and fields */
 671         proto_pppoed = proto_register_protocol("PPP-over-Ethernet Discovery",
 672                                                "PPPoED", "pppoed");
 673         proto_register_subtree_array(ett, array_length(ett));
 674         proto_register_field_array(proto_pppoed, hf, array_length(hf));
 675
 676         /* Preference setting */
 677         pppoed_module = prefs_register_protocol(proto_pppoed, NULL);
 678         prefs_register_bool_preference(pppoed_module, "show_tags_and_lengths",
 679                                        "Show tag values and lengths",
 680                                        "Show values of tags and lengths of data fields",
 681                                        &global_pppoe_show_tags_and_lengths);
 682 }
 683
 684 void proto_reg_handoff_pppoed(void)
 685 {
 686         dissector_handle_t pppoed_handle;
 687
 688         pppoed_handle = create_dissector_handle(dissect_pppoed, proto_pppoed);
 689         dissector_add("ethertype", ETHERTYPE_PPPOED, pppoed_handle);
 690 }
 691
 692
 693 /* Session protocol, i.e. PPP session established */
 694 static void dissect_pppoes(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 695 {
 696         guint8  pppoe_code;
 697         guint16 pppoe_session_id;
 698         guint16 reported_payload_length;
 699         guint16 poe_tag;
 700         guint16 poe_tag_length;
 701         gint    actual_payload_length;
 702         gint    length, reported_length;
 703         gint    credit_offset = 0, tagstart = 0;
 704
 705         proto_tree  *pppoe_tree;
 706         proto_item  *ti = NULL;
 707         tvbuff_t    *next_tvb;
 708
 709         col_set_str(pinfo->cinfo, COL_PROTOCOL, "PPPoES");
 710         col_clear(pinfo->cinfo, COL_INFO);
 711
 712         /* Start Decoding Here. */
 713         pppoe_code = tvb_get_guint8(tvb, 1);
 714
 715         if (check_col(pinfo->cinfo,COL_INFO))
 716         {
 717                 col_add_str(pinfo->cinfo, COL_INFO,
 718                              val_to_str(pppoe_code, code_vals, "Unknown"));
 719         }
 720
 721         pppoe_session_id = tvb_get_ntohs(tvb, 2);
 722         reported_payload_length = tvb_get_ntohs(tvb, 4);
 723         actual_payload_length = tvb_reported_length_remaining(tvb, 6);
 724
 725         if (tree)
 726         {
 727                 ti = proto_tree_add_item(tree, proto_pppoes, tvb, 0, 6, FALSE);
 728                 pppoe_tree = proto_item_add_subtree(ti, ett_pppoe);
 729
 730                 proto_tree_add_item(pppoe_tree, hf_pppoe_version, tvb, 0, 1, FALSE);
 731                 proto_tree_add_item(pppoe_tree, hf_pppoe_type, tvb, 0, 1, FALSE);
 732                 proto_tree_add_item(pppoe_tree, hf_pppoe_code, tvb, 1, 1, FALSE);
 733                 proto_tree_add_item(pppoe_tree, hf_pppoe_session_id, tvb, 2, 2, FALSE);
 734                 ti = proto_tree_add_item(pppoe_tree, hf_pppoe_payload_length, tvb, 4, 2, FALSE);
 735
 736
 737                 if (PPPOE_TAG_CREDITS == tvb_get_ntohs(tvb, 6))
 738                 {
 739                         tagstart = 6;
 740                         poe_tag = tvb_get_ntohs(tvb, tagstart);
 741                         poe_tag_length = tvb_get_ntohs(tvb, tagstart + 2);
 742
 743                         /* Create tags subtree */
 744                         ti = proto_tree_add_item(pppoe_tree, hf_pppoes_tags, tvb, tagstart, 8, FALSE);
 745                         pppoe_tree = proto_item_add_subtree(ti, ett_pppoes_tags);
 746
 747                         /* Show tag data */
 748                         if (poe_tag_length == 4)
 749                         {
 750                                 proto_tree_add_item(pppoe_tree, hf_pppoes_tag_credits_fcn, tvb,
 751                                         tagstart+4, 2, FALSE);
 752                                 proto_tree_add_item(pppoe_tree, hf_pppoes_tag_credits_bcn, tvb,
 753                                         tagstart+6, 2, FALSE);
 754                         } else {
 755                                 proto_tree_add_item(pppoe_tree, hf_pppoed_tag_credits, tvb,
 756                                         tagstart+4, poe_tag_length, FALSE);
 757                         }
 758
 759                         credit_offset = 8;
 760                 }
 761         }
 762
 763         /*
 764          * The only reason why the payload length from the header
 765          * should differ from the remaining data in the packet
 766          * would be if the total packet length, including Ethernet
 767          * CRC, were < 64 bytes, so that padding was required.
 768          *
 769          * That means that you have 14 bytes of Ethernet header,
 770          * 4 bytes of FCS, and fewer than 46 bytes of PPPoE packet.
 771          *
 772          * If that's not the case, we report a difference between
 773          * the payload length in the packet, and the amount of
 774          * data following the PPPoE header, as an error.
 775          */
 776         if (tvb_reported_length(tvb) > 46) {
 777                 /*
 778                  * Be forgiving about a possible trailing FCS.
 779                  *
 780                  * XXX - this dissector currently doesn't know
 781                  * whether any extra data past the end of the PPP
 782                  * payload is an FCS or not.
 783                  *
 784                  * If we know that we have an FCS, or that we don't
 785                  * have an FCS, we should have been handed a tvbuff
 786                  * without the FCS, and we should just do the strict
 787                  * length check.
 788                  *
 789                  * If we don't know whether we have an FCS, then:
 790                  *
 791                  *   if this isn't over Ethernet - the "E" in "PPPoE"
 792                  *   nonwithstanding, it can also run on top of 802.11,
 793                  *   for example - there's no trailer, so any data
 794                  *   past the payload length is either an FCS or
 795                  *   bogus;
 796                  *
 797                  *   if this is over Ethernet, there shouldn't be
 798                  *   a trailer, as the packet is long enough not to
 799                  *   require a trailer, as per the above;
 800                  *
 801                  * so perhaps we should assume that if we have exactly
 802                  * 4 bytes of extra information, it's an FCS, otherwise
 803                  * it's not.
 804                  *
 805                  * Perhaps we need to have a routine to call to
 806                  * do all the length checking, etc., and call it
 807                  * from here and from other dissectors where the
 808                  * protocol has a length field, or have a way to
 809                  * tell the dissector that called us which field
 810                  * has the length field and have *that* dissector
 811                  * do the length checking and add the expert info
 812                  * to the length field, *after* it does all the
 813                  * FCS heuristics.
 814                  */
 815                 if ((reported_payload_length != actual_payload_length) &&
 816                 ((reported_payload_length + 4) != actual_payload_length)) {
 817                     proto_item_append_text(ti, " [incorrect, should be %u]",
 818                         actual_payload_length);
 819                     expert_add_info_format(pinfo, ti, PI_MALFORMED,
 820                         PI_WARN, "Possible bad payload length %u != %u",
 821                         reported_payload_length, actual_payload_length);
 822                 }
 823         }
 824
 825         /*
 826          * Construct a tvbuff containing the PPP packet.
 827          */
 828         length = tvb_length_remaining(tvb, 6);
 829         reported_length = tvb_reported_length_remaining(tvb, 6);
 830         DISSECTOR_ASSERT(length >= 0);
 831         DISSECTOR_ASSERT(reported_length >= 0);
 832         if (length > reported_length)
 833                 length = reported_length;
 834         if ((guint)length > reported_payload_length)
 835                 length = reported_payload_length;
 836         if ((guint)reported_length > reported_payload_length)
 837                 reported_length = reported_payload_length;
 838         next_tvb = tvb_new_subset(tvb,(6 + credit_offset),
 839                                 (length - credit_offset),
 840                                 (reported_length - credit_offset));
 841         call_dissector(ppp_handle,next_tvb,pinfo,tree);
 842 }
 843
 844 void proto_register_pppoes(void)
 845 {
 846
 847         static hf_register_info hf[] =
 848         {
 849                 { &hf_pppoes_tags,
 850                         { "PPPoE Tags", "pppoes.tags", FT_NONE, BASE_NONE,
 851                                  NULL, 0x0, NULL, HFILL
 852                         }
 853                 },
 854                 { &hf_pppoes_tag,
 855                         { "Tag", "pppoes.tag", FT_UINT16, BASE_HEX,
 856                                  VALS(tag_vals), 0x0, NULL, HFILL
 857                         }
 858                 },
 859                 { &hf_pppoes_tag_credits,
 860                         { "Credits", "pppoes.tags.credits", FT_BYTES, BASE_NONE,
 861                                  NULL, 0x0, NULL, HFILL
 862                         }
 863                 },
 864                 { &hf_pppoes_tag_credits_fcn,
 865                         { "FCN", "pppoes.tags.credits.fcn", FT_UINT16, BASE_DEC,
 866                                  NULL, 0x0, NULL, HFILL
 867                         }
 868                 },
 869                 { &hf_pppoes_tag_credits_bcn,
 870                         { "BCN", "pppoes.tags.credits.bcn", FT_UINT16, BASE_DEC,
 871                                  NULL, 0x0, NULL, HFILL
 872                         }
 873                 }
 874         };
 875
 876         static gint *ett[] = {
 877                 &ett_pppoes,
 878                 &ett_pppoes_tags
 879         };
 880
 881         /* Register protocol */
 882         proto_pppoes = proto_register_protocol("PPP-over-Ethernet Session", "PPPoES", "pppoes");
 883
 884         proto_register_subtree_array(ett, array_length(ett));
 885         proto_register_field_array(proto_pppoes, hf, array_length(hf));
 886 }
 887
 888 void proto_register_pppoe(void)
 889 {
 890         static hf_register_info hf[] =
 891         {
 892                 /* These fields common to discovery and session protocols */
 893                 { &hf_pppoe_version,
 894                         { "Version", "pppoe.version", FT_UINT8, BASE_DEC,
 895                                  NULL, 0xf0, NULL, HFILL
 896                         }
 897                 },
 898                 { &hf_pppoe_type,
 899                         { "Type", "pppoe.type", FT_UINT8, BASE_DEC,
 900                                  NULL, 0x0f, NULL, HFILL
 901                         }
 902                 },
 903                 { &hf_pppoe_code,
 904                         { "Code", "pppoe.code", FT_UINT8, BASE_HEX,
 905                                  VALS(code_vals), 0x0, NULL, HFILL
 906                         }
 907                 },
 908                 { &hf_pppoe_session_id,
 909                         { "Session ID", "pppoe.session_id", FT_UINT16, BASE_HEX,
 910                                  NULL, 0x0, NULL, HFILL
 911                         }
 912                 },
 913                 { &hf_pppoe_payload_length,
 914                         { "Payload Length", "pppoe.payload_length", FT_UINT16, BASE_DEC,
 915                                  NULL, 0x0, NULL, HFILL
 916                         }
 917                 }
 918         };
 919
 920         static gint *ett[] = {
 921                 &ett_pppoe
 922         };
 923
 924         /* Register protocol */
 925         proto_pppoe = proto_register_protocol("PPP-over-Ethernet", "PPPoE", "pppoe");
 926
 927         proto_register_subtree_array(ett, array_length(ett));
 928         proto_register_field_array(proto_pppoe, hf, array_length(hf));
 929
 930 }
 931
 932 void proto_reg_handoff_pppoes(void)
 933 {
 934         dissector_handle_t pppoes_handle  =
 935             create_dissector_handle(dissect_pppoes, proto_pppoes);
 936         dissector_add("ethertype", ETHERTYPE_PPPOES, pppoes_handle);
 937
 938         /* Get a handle for the PPP dissector */
 939         ppp_handle = find_dissector("ppp");
 940 }