plugins/docsis/packet-docsis.c

   1 /* packet-docsis.c
   2  * Routines for docsis dissection
   3  * Copyright 2002, Anand V. Narwani <anand[AT]narwani.org>
   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  24  */
  25
  26
  27 /* This code is based on the DOCSIS 1.1 specification available at:
  28  * http://www.cablemodem.com/specifications/specifications11.html
  29  *
  30  * DOCSIS Captures can be facilitated using the Cable Monitor Feature
  31  * available on Cisco Cable Modem Termination Systems :
  32  * http://www.cisco.com/univercd/cc/td/doc/product/cable/cab_rout/cmtsfg/ufg_cmon.htm
  33  *
  34  * This dissector depends on the presence of a DOCSIS enapsulation type.
  35  * There is no simple way to distinguish DOCSIS Frames from Ethernet frames,
  36  * since the frames are copied from the RF interface on the CMTS to
  37  * a Fast Ethernet interface; thus a preference was needed to enable
  38  * the DOCSIS encapsulation type.
  39  *
  40  * The current CVS version of libpcap allows a link-layer header type to
  41  * be specified for some interfaces on some platforms; for Ethernet
  42  * interfaces, it allows DOCSIS to be specified.  If an Ethernet capture
  43  * is done with a link-layer type of DOCSIS, the file will have a link-
  44  * layer type of DLT_DOCSIS; Wireshark will treat the frames in that capture
  45  * as DOCSIS frames.
  46  */
  47
  48 #include "config.h"
  49
  50 #include <epan/packet.h>
  51 #include <epan/exceptions.h>
  52
  53 #define FCTYPE_PACKET 0x00
  54 #define FCTYPE_ATMPDU 0x01
  55 #define FCTYPE_RESRVD 0x02
  56 #define FCTYPE_MACSPC 0x03
  57
  58 #define EH_NULL_CONFIG 0
  59 #define EH_REQUEST 1
  60 #define EH_ACK_REQ 2
  61 #define EH_BP_UP 3
  62 #define EH_BP_DOWN 4
  63 #define EH_SFLOW_HDR_DOWN 5
  64 #define EH_SFLOW_HDR_UP 6
  65 #define EH_BP_UP2 7
  66 #define EH_DS_SERVICE 8
  67 #define EH_RESERVED_9 9
  68 #define EH_RESERVED_10 10
  69 #define EH_RESERVED_11 11
  70 #define EH_RESERVED_12 12
  71 #define EH_RESERVED_13 13
  72 #define EH_RESERVED_14 14
  73 #define EH_EXTENDED 15
  74
  75 /* Initialize the protocol and registered fields */
  76 static int proto_docsis = -1;
  77 static int hf_docsis_fctype = -1;
  78 static int hf_docsis_machdr_fcparm = -1;
  79 static int hf_docsis_fcparm = -1;
  80 static int hf_docsis_ehdron = -1;
  81 static int hf_docsis_concat_cnt = -1;
  82 static int hf_docsis_macparm = -1;
  83 static int hf_docsis_ehdrlen = -1;
  84 static int hf_docsis_lensid = -1;
  85 static int hf_docsis_eh_type = -1;
  86 static int hf_docsis_eh_len = -1;
  87 static int hf_docsis_eh_val = -1;
  88 static int hf_docsis_frag_rsvd = -1;
  89 static int hf_docsis_frag_first = -1;
  90 static int hf_docsis_frag_last = -1;
  91 static int hf_docsis_frag_seq = -1;
  92 static int hf_docsis_sid = -1;
  93 static int hf_docsis_mini_slots = -1;
  94 static int hf_docsis_hcs = -1;
  95 static int hf_docsis_bpi_en = -1;
  96 static int hf_docsis_toggle_bit = -1;
  97 static int hf_docsis_key_seq = -1;
  98 static int hf_docsis_ehdr_ver = -1;
  99 static int hf_docsis_said = -1;
 100 static int hf_docsis_ehdr_phsi = -1;
 101 static int hf_docsis_ehdr_qind = -1;
 102 static int hf_docsis_ehdr_grants = -1;
 103 static int hf_docsis_reserved = -1;
 104 static int hf_docsis_ehdr_ds_traffic_pri = -1;
 105 static int hf_docsis_ehdr_ds_seq_chg_cnt = -1;
 106 static int hf_docsis_ehdr_ds_dsid = -1;
 107 static int hf_docsis_ehdr_ds_pkt_seq_num = -1;
 108 static int hf_docsis_ehdr_bpup2_bpi_en = -1;
 109 static int hf_docsis_ehdr_bpup2_toggle_bit = -1;
 110 static int hf_docsis_ehdr_bpup2_key_seq = -1;
 111 static int hf_docsis_ehdr_bpup2_ver = -1;
 112 static int hf_docsis_ehdr_bpup2_sid = -1;
 113 static dissector_handle_t docsis_handle;
 114 static dissector_handle_t eth_withoutfcs_handle;
 115 static dissector_handle_t data_handle;
 116 static dissector_handle_t docsis_mgmt_handle;
 117 #if 0
 118 static dissector_table_t docsis_dissector_table;
 119 #endif
 120
 121 /* Initialize the subtree pointers */
 122 static gint ett_docsis = -1;
 123 static gint ett_ehdr = -1;
 124
 125 static const value_string fctype_vals[] = {
 126   {FCTYPE_PACKET, "Packet PDU"},
 127   {FCTYPE_ATMPDU, "ATM PDU"},
 128   {FCTYPE_RESRVD, "Reserved"},
 129   {FCTYPE_MACSPC, "MAC Specific"},
 130   {0, NULL}
 131 };
 132
 133 static const value_string eh_type_vals[] = {
 134   {0, "NULL Configuration Parameter"},
 135   {EH_REQUEST, "Request"},
 136   {EH_ACK_REQ, "Acknowledgement Requested"},
 137   {EH_BP_UP, "Upstream Privacy Element"},
 138   {EH_BP_DOWN, "Downstream  Privacy Element"},
 139   {EH_SFLOW_HDR_UP, "Service Flow EH; PHS Header Upstream"},
 140   {EH_SFLOW_HDR_DOWN, "Service Flow EH; PHS Header Downstream"},
 141   {EH_BP_UP2, "Upstream Privacy with Multi Channel"},
 142   {EH_DS_SERVICE, "Downstream Service"},
 143   {EH_RESERVED_9, "Reserved"},
 144   {EH_RESERVED_10, "Reserved"},
 145   {EH_RESERVED_10, "Reserved"},
 146   {EH_RESERVED_11, "Reserved"},
 147   {EH_RESERVED_12, "Reserved"},
 148   {EH_RESERVED_13, "Reserved"},
 149   {EH_RESERVED_14, "Reserved"},
 150   {EH_EXTENDED, "Extended"},
 151   {0, NULL}
 152 };
 153
 154 static const value_string fcparm_vals[] = {
 155   {0x0, "Timing Header"},
 156   {0x1, "Mac Management Message"},
 157   {0x2, "Request Frame"},
 158   {0x3, "Fragmentation Header"},
 159   {0x1C, "Concatenation Header"},
 160   {0, NULL}
 161 };
 162
 163 static const true_false_string ehdron_tfs = {
 164   "Extended Header Present",
 165   "Extended Header Absent"
 166 };
 167
 168 static const true_false_string ena_dis_tfs = {
 169   "Enabled",
 170   "Disabled"
 171 };
 172
 173 static const true_false_string qind_tfs = {
 174   "Rate overrun",
 175   "Rate non-overrun"
 176 };
 177
 178 static const true_false_string odd_even_tfs = {
 179   "Odd Key",
 180   "Even Key",
 181 };
 182
 183 /* Code to actually dissect the packets */
 184 /* Code to Dissect the extended header */
 185 static void
 186 dissect_ehdr (tvbuff_t * tvb, proto_tree * tree, gboolean isfrag)
 187 {
 188   proto_tree *ehdr_tree;
 189   proto_item *it, *item;
 190   gint ehdrlen;
 191   int pos;
 192   guint8 type;
 193   guint8 len;
 194   guint8 val;
 195   guint8 mini_slots;
 196   guint16 sid;
 197
 198   ehdrlen = tvb_get_guint8 (tvb, 1);
 199   pos = 4;
 200
 201   it = proto_tree_add_text (tree, tvb, pos, ehdrlen, "Extended Header");
 202   ehdr_tree = proto_item_add_subtree (it, ett_ehdr);
 203   while (pos < ehdrlen + 4)
 204     {
 205       type = (tvb_get_guint8 (tvb, pos) & 0xF0);
 206       len = (tvb_get_guint8 (tvb, pos) & 0x0F);
 207       if ((((type >> 4) & 0x0F)== 6) && (len == 2))
 208         {
 209           item = proto_tree_add_item(ehdr_tree, hf_docsis_eh_type, tvb, pos, 1, ENC_BIG_ENDIAN);
 210           PROTO_ITEM_SET_HIDDEN(item);
 211           proto_tree_add_text(ehdr_tree, tvb, pos, 1, "0110 ....  = Unsolicited Grant Sync EHDR Sub-Element" );
 212         }
 213       else
 214         proto_tree_add_item (ehdr_tree, hf_docsis_eh_type, tvb, pos, 1, ENC_BIG_ENDIAN);
 215       proto_tree_add_item (ehdr_tree, hf_docsis_eh_len, tvb, pos, 1, ENC_BIG_ENDIAN);
 216       switch ((type >> 4) & 0x0F)
 217         {
 218         case EH_REQUEST:
 219           if (len == 3)
 220             {
 221               mini_slots = tvb_get_guint8 (tvb, pos + 1);
 222               sid = tvb_get_ntohs (tvb, pos + 2);
 223               proto_tree_add_uint (ehdr_tree, hf_docsis_mini_slots, tvb,
 224                                    pos + 1, 1, mini_slots);
 225               proto_tree_add_uint (ehdr_tree, hf_docsis_sid, tvb, pos + 2, 2,
 226                                    sid);
 227             }
 228           else
 229             {
 230               THROW (ReportedBoundsError);
 231             }
 232           break;
 233         case EH_ACK_REQ:
 234           if (len == 2)
 235             {
 236               sid = tvb_get_ntohs (tvb, pos + 1);
 237               proto_tree_add_uint (ehdr_tree, hf_docsis_sid, tvb, pos + 2, 2,
 238                                    sid);
 239             }
 240           else
 241             {
 242               THROW (ReportedBoundsError);
 243             }
 244         case EH_BP_UP:
 245           proto_tree_add_item (ehdr_tree, hf_docsis_key_seq, tvb, pos + 1, 1,
 246                                ENC_BIG_ENDIAN);
 247           proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_ver, tvb, pos + 1, 1,
 248                                ENC_BIG_ENDIAN);
 249           proto_tree_add_item (ehdr_tree, hf_docsis_bpi_en, tvb, pos + 2, 1,
 250                                ENC_BIG_ENDIAN);
 251           proto_tree_add_item (ehdr_tree, hf_docsis_toggle_bit, tvb, pos + 2,
 252                                1, ENC_BIG_ENDIAN);
 253           proto_tree_add_item (ehdr_tree, hf_docsis_sid, tvb, pos + 2, 2,
 254                                ENC_BIG_ENDIAN);
 255           proto_tree_add_item (ehdr_tree, hf_docsis_mini_slots, tvb, pos + 4,
 256                                1, ENC_BIG_ENDIAN);
 257           if (isfrag)
 258             {
 259               proto_tree_add_item (ehdr_tree, hf_docsis_frag_rsvd, tvb, pos+5,
 260                                   1, ENC_BIG_ENDIAN);
 261               proto_tree_add_item (ehdr_tree, hf_docsis_frag_first, tvb, pos+5,
 262                                   1, ENC_BIG_ENDIAN);
 263               proto_tree_add_item (ehdr_tree, hf_docsis_frag_last, tvb, pos+5,
 264                                   1, ENC_BIG_ENDIAN);
 265               proto_tree_add_item (ehdr_tree, hf_docsis_frag_seq, tvb, pos+5,
 266                                   1, ENC_BIG_ENDIAN);
 267             }
 268           break;
 269         case EH_BP_DOWN:
 270           proto_tree_add_item (ehdr_tree, hf_docsis_key_seq, tvb, pos + 1, 1,
 271                                ENC_BIG_ENDIAN);
 272           proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_ver, tvb, pos + 1, 1,
 273                                ENC_BIG_ENDIAN);
 274           proto_tree_add_item (ehdr_tree, hf_docsis_bpi_en, tvb, pos + 2, 1,
 275                                ENC_BIG_ENDIAN);
 276           proto_tree_add_item (ehdr_tree, hf_docsis_toggle_bit, tvb, pos + 2,
 277                                1, ENC_BIG_ENDIAN);
 278           proto_tree_add_item (ehdr_tree, hf_docsis_said, tvb, pos + 2, 2,
 279                                ENC_BIG_ENDIAN);
 280           proto_tree_add_item (ehdr_tree, hf_docsis_reserved, tvb, pos + 4, 1,
 281                                ENC_BIG_ENDIAN);
 282           break;
 283         case EH_SFLOW_HDR_DOWN:
 284         case EH_SFLOW_HDR_UP:
 285           val = tvb_get_guint8 (tvb, pos+1);
 286           if (val == 0)
 287           {
 288             item = proto_tree_add_item(ehdr_tree, hf_docsis_ehdr_phsi, tvb, pos+1, 1, ENC_BIG_ENDIAN);
 289                 PROTO_ITEM_SET_HIDDEN(item);
 290             proto_tree_add_text (ehdr_tree, tvb, pos+1, 1, "0000 0000 = No PHS on current packet" );
 291           }
 292           else
 293             proto_tree_add_item(ehdr_tree, hf_docsis_ehdr_phsi, tvb, pos+1, 1, ENC_BIG_ENDIAN);
 294
 295           if (len == 2)
 296           {
 297             proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_qind, tvb, pos+2, 1, ENC_BIG_ENDIAN);
 298             proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_grants, tvb, pos+2, 1, ENC_BIG_ENDIAN);
 299           }
 300           break;
 301         case EH_BP_UP2:
 302           proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_bpup2_key_seq, tvb, pos + 1, 1,
 303                                ENC_BIG_ENDIAN);
 304           proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_bpup2_ver, tvb, pos + 1, 1,
 305                                ENC_BIG_ENDIAN);
 306           proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_bpup2_bpi_en, tvb, pos + 2, 1,
 307                                ENC_BIG_ENDIAN);
 308           proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_bpup2_toggle_bit, tvb, pos + 2,
 309                                1, ENC_BIG_ENDIAN);
 310           proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_bpup2_sid, tvb, pos + 2, 2,
 311                                ENC_BIG_ENDIAN);
 312           break;
 313         case EH_DS_SERVICE:
 314           proto_tree_add_item(ehdr_tree, hf_docsis_ehdr_ds_traffic_pri, tvb, pos+1, 1, FALSE);
 315
 316           if (len == 3)
 317           {
 318             proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_ds_dsid, tvb, pos+1, 3, FALSE);
 319           }
 320
 321           if (len == 5)
 322           {
 323             proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_ds_seq_chg_cnt, tvb, pos+1, 1, FALSE);
 324             proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_ds_dsid, tvb, pos+1, 3, FALSE);
 325             proto_tree_add_item (ehdr_tree, hf_docsis_ehdr_ds_pkt_seq_num, tvb, pos+4, 2, FALSE);
 326           }
 327
 328           break;
 329         default:
 330           if (len > 0)
 331             proto_tree_add_item (ehdr_tree, hf_docsis_eh_val, tvb, pos + 1,
 332                                   len, ENC_NA);
 333         }
 334       pos += len + 1;
 335     }
 336
 337   return;
 338 }
 339
 340
 341 static void
 342 dissect_docsis (tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 343 {
 344   guint8 fc;
 345   guint8 fctype;
 346   guint8 fcparm;
 347   guint8 ehdron;
 348   gint mac_parm;
 349   gint hdrlen;
 350   guint16 len_sid;
 351   tvbuff_t *next_tvb, *mgt_tvb;
 352   gint pdulen, captured_length;
 353   gint framelen;
 354   gboolean isfrag = FALSE;
 355   gint oldconcatlen;
 356
 357 /* Set up structures needed to add the protocol subtree and manage it */
 358   proto_item *ti;
 359   proto_tree *docsis_tree;
 360 /* concatlen and concatpos are declared static to allow for recursive calls to
 361  * the dissect_docsis routine when dissecting Concatenated frames
 362  */
 363   static gint concatlen;
 364   static gint concatpos;
 365
 366 /* Extract important fields */
 367   fc = tvb_get_guint8 (tvb, 0); /* Frame Control Byte */
 368   fctype = (fc >> 6) & 0x03;    /* Frame Control Type:  2 MSB Bits */
 369   fcparm = (fc >> 1) & 0x1F;    /* Frame Control Parameter: Next 5 Bits */
 370   ehdron = (fc & 0x01);         /* Extended Header Bit: LSB */
 371
 372   mac_parm = tvb_get_guint8 (tvb, 1);   /* Mac Parm */
 373   len_sid = tvb_get_ntohs (tvb, 2);     /* Length Or SID */
 374
 375 /* set Header length based on presence of Extended header */
 376   if (ehdron == 0x00)
 377     hdrlen = 6;
 378   else
 379     hdrlen = 6 + mac_parm;
 380
 381 /* Captured PDU Length is based on the length of the header */
 382   captured_length = tvb_length_remaining (tvb, hdrlen);
 383
 384 /* If this is a Request Frame, then pdulen is 0 and framelen is 6 */
 385   if ((fctype == FCTYPE_MACSPC) && fcparm == 0x02)
 386     {
 387       pdulen = 0;
 388       framelen = 6;
 389     }
 390   else
 391     {
 392       framelen = 6 + len_sid;
 393       pdulen = len_sid - (mac_parm + 2);
 394     }
 395
 396 /* if this is a concatenated frame setup the length of the concatenated
 397  * frame and set the position to the first byte of the first frame */
 398   if ((fctype == FCTYPE_MACSPC) && (fcparm == 0x1c))
 399     {
 400       concatlen = len_sid;
 401       concatpos = 6;
 402     }
 403
 404 /* Make entries in Protocol column and Info column on summary display */
 405   col_set_str (pinfo->cinfo, COL_PROTOCOL, "DOCSIS");
 406
 407   switch (fctype)
 408     {
 409     case FCTYPE_PACKET:
 410       col_set_str (pinfo->cinfo, COL_INFO, "Packet PDU");
 411       break;
 412     case FCTYPE_ATMPDU:
 413       col_set_str (pinfo->cinfo, COL_INFO, "ATM PDU");
 414       break;
 415     case FCTYPE_RESRVD:
 416       col_set_str (pinfo->cinfo, COL_INFO, "Reserved PDU");
 417       break;
 418     case FCTYPE_MACSPC:
 419       if (fcparm == 0x02)
 420         col_add_fstr (pinfo->cinfo, COL_INFO,
 421                       "Request Frame SID = %u Mini Slots = %u", len_sid,
 422                       mac_parm);
 423       else if (fcparm == 0x03)
 424         col_set_str (pinfo->cinfo, COL_INFO, "Fragmented Frame");
 425       else
 426         col_set_str (pinfo->cinfo, COL_INFO, "Mac Specific");
 427       break;
 428     }  /* switch */
 429
 430 /* In the interest of speed, if "tree" is NULL, don't do any work not
 431    necessary to generate protocol tree items. */
 432   if (tree)
 433     {
 434       ti = proto_tree_add_protocol_format (tree, proto_docsis, tvb, 0,
 435                                            hdrlen, "DOCSIS");
 436       docsis_tree = proto_item_add_subtree (ti, ett_docsis);
 437
 438 /* add an item to the subtree, see section 1.6 for more information */
 439       proto_tree_add_item (docsis_tree, hf_docsis_fctype, tvb, 0, 1, ENC_BIG_ENDIAN);
 440       switch (fctype)
 441         {
 442         case FCTYPE_PACKET:
 443         case FCTYPE_ATMPDU:
 444         case FCTYPE_RESRVD:
 445           proto_tree_add_item (docsis_tree, hf_docsis_fcparm, tvb, 0, 1,
 446                                ENC_BIG_ENDIAN);
 447           proto_tree_add_item (docsis_tree, hf_docsis_ehdron, tvb, 0, 1,
 448                                ENC_BIG_ENDIAN);
 449           if (ehdron == 0x01)
 450             {
 451               proto_tree_add_item (docsis_tree, hf_docsis_ehdrlen, tvb, 1, 1,
 452                                    ENC_BIG_ENDIAN);
 453               proto_tree_add_item (docsis_tree, hf_docsis_lensid, tvb, 2, 2,
 454                                    ENC_BIG_ENDIAN);
 455               dissect_ehdr (tvb, docsis_tree, isfrag);
 456               proto_tree_add_item (docsis_tree, hf_docsis_hcs, tvb,
 457                                    4 + mac_parm, 2, ENC_BIG_ENDIAN);
 458             }
 459           else
 460             {
 461               proto_tree_add_item (docsis_tree, hf_docsis_macparm, tvb, 1, 1,
 462                                    ENC_BIG_ENDIAN);
 463               proto_tree_add_item (docsis_tree, hf_docsis_lensid, tvb, 2, 2,
 464                                    ENC_BIG_ENDIAN);
 465               proto_tree_add_item (docsis_tree, hf_docsis_hcs, tvb, 4, 2,
 466                                    ENC_BIG_ENDIAN);
 467             }
 468           break;
 469         case FCTYPE_MACSPC:
 470           proto_tree_add_item (docsis_tree, hf_docsis_machdr_fcparm, tvb, 0,
 471                                1, ENC_BIG_ENDIAN);
 472           proto_tree_add_item (docsis_tree, hf_docsis_ehdron, tvb, 0, 1,
 473                                ENC_BIG_ENDIAN);
 474           /* Decode for a Request Frame.  No extended header */
 475           if (fcparm == 0x02)
 476             {
 477               proto_tree_add_uint (docsis_tree, hf_docsis_mini_slots, tvb, 1,
 478                                    1, mac_parm);
 479               proto_tree_add_uint (docsis_tree, hf_docsis_sid, tvb, 2, 2,
 480                                    len_sid);
 481               proto_tree_add_item (docsis_tree, hf_docsis_hcs, tvb, 4, 2,
 482                                    ENC_BIG_ENDIAN);
 483               break;
 484             }
 485           /* Check if this is a fragmentation header */
 486           if (fcparm == 0x03)
 487             {
 488               isfrag = TRUE;
 489             }
 490           /* Decode for a Concatenated Header.  No Extended Header */
 491           if (fcparm == 0x1c)
 492             {
 493               proto_item_append_text (ti, " (Concatenated Header)");
 494               proto_tree_add_item (docsis_tree, hf_docsis_concat_cnt, tvb, 1,
 495                                    1, ENC_BIG_ENDIAN);
 496               proto_tree_add_item (docsis_tree, hf_docsis_lensid, tvb, 2, 2,
 497                                    ENC_BIG_ENDIAN);
 498               proto_tree_add_item (docsis_tree, hf_docsis_hcs, tvb, 4, 2,
 499                                    ENC_BIG_ENDIAN);
 500               break;
 501             }
 502           /* If Extended header is present then decode it */
 503           if (ehdron == 0x01)
 504             {
 505               proto_tree_add_item (docsis_tree, hf_docsis_ehdrlen, tvb, 1, 1,
 506                                    ENC_BIG_ENDIAN);
 507               proto_tree_add_item (docsis_tree, hf_docsis_lensid, tvb, 2, 2,
 508                                    ENC_BIG_ENDIAN);
 509               dissect_ehdr (tvb, docsis_tree, isfrag);
 510               proto_tree_add_item (docsis_tree, hf_docsis_hcs, tvb,
 511                                    4 + mac_parm, 2, ENC_BIG_ENDIAN);
 512               break;
 513             }
 514           /* default case for all other Mac Frame Types */
 515           proto_tree_add_item (docsis_tree, hf_docsis_macparm, tvb, 1, 1,
 516                                ENC_BIG_ENDIAN);
 517           proto_tree_add_item (docsis_tree, hf_docsis_lensid, tvb, 2, 2,
 518                                ENC_BIG_ENDIAN);
 519           proto_tree_add_item (docsis_tree, hf_docsis_hcs, tvb, 4, 2, ENC_BIG_ENDIAN);
 520           break;
 521         }
 522     }
 523
 524 /* If this protocol has a sub-dissector call it here, see section 1.8 */
 525   switch (fctype)
 526     {
 527     case FCTYPE_PACKET:
 528     case FCTYPE_RESRVD:
 529       if (pdulen >= 0)
 530         {
 531           if (pdulen > 0)
 532             {
 533               next_tvb = tvb_new_subset (tvb, hdrlen, captured_length, pdulen);
 534               call_dissector (eth_withoutfcs_handle, next_tvb, pinfo, tree);
 535             }
 536           if (concatlen > 0)
 537             {
 538               concatlen = concatlen - framelen;
 539               concatpos += framelen;
 540             }
 541         }
 542       break;
 543     case FCTYPE_MACSPC:
 544       switch (fcparm)
 545         {
 546         case 0x00:
 547         case 0x01:
 548           if (pdulen > 0)
 549             {
 550               mgt_tvb = tvb_new_subset (tvb, hdrlen, captured_length, pdulen);
 551               call_dissector (docsis_mgmt_handle, mgt_tvb, pinfo, tree);
 552             }
 553           if (concatlen > 0)
 554             {
 555               concatlen = concatlen - framelen;
 556               concatpos += framelen;
 557             }
 558           break;
 559         case 0x02:
 560           /* Don't do anything for a Request Frame */
 561           break;
 562         case 0x03:
 563           /* For Fragmentation Frames simply dissect using the data
 564            * dissector as we don't handle them yet
 565            */
 566           if (pdulen > 0)
 567             {
 568               mgt_tvb = tvb_new_subset (tvb, hdrlen, captured_length, pdulen);
 569               call_dissector (data_handle, mgt_tvb, pinfo, tree);
 570             }
 571           if (concatlen > 0)
 572             {
 573               concatlen = concatlen - framelen;
 574               concatpos += framelen;
 575             }
 576           break;
 577         case 0x1c:
 578           /* call the docsis dissector on the same frame
 579            * to dissect DOCSIS frames within the concatenated
 580            * frame.  concatpos and concatlen are declared
 581            * static and are decremented and incremented
 582            * respectively when the inner
 583            * docsis frames are dissected. */
 584           while (concatlen > 0)
 585             {
 586               oldconcatlen = concatlen;
 587               next_tvb = tvb_new_subset (tvb, concatpos, -1, concatlen);
 588               call_dissector (docsis_handle, next_tvb, pinfo, tree);
 589               if (oldconcatlen <= concatlen)
 590                 THROW(ReportedBoundsError);
 591             }
 592           concatlen = 0;
 593           concatpos = 0;
 594           col_set_str(pinfo->cinfo, COL_INFO, "Concatenated Frame");
 595           break;
 596         }
 597       break;
 598     }
 599 }
 600
 601
 602 /* Register the protocol with Wireshark */
 603
 604 /* this format is require because a script is used to build the C function
 605    that calls all the protocol registration.
 606 */
 607
 608
 609 void
 610 proto_register_docsis (void)
 611 {
 612
 613 /* Setup list of header fields  See Section 1.6.1 for details*/
 614   static hf_register_info hf[] = {
 615     {&hf_docsis_fctype,
 616      {"FCType", "docsis.fctype",
 617       FT_UINT8, BASE_HEX, VALS (fctype_vals), 0xC0,
 618       "Frame Control Type", HFILL}
 619      },
 620     {&hf_docsis_fcparm,
 621      {"FCParm", "docsis.fcparm",
 622       FT_UINT8, BASE_DEC, NULL, 0x3E,
 623       "Parameter Field", HFILL}
 624      },
 625     {&hf_docsis_machdr_fcparm,
 626      {"FCParm", "docsis.fcparm",
 627       FT_UINT8, BASE_HEX, VALS (fcparm_vals), 0x3E,
 628       "Parameter Field", HFILL}
 629      },
 630     {&hf_docsis_ehdron,
 631      {"EHDRON", "docsis.ehdron",
 632       FT_BOOLEAN, 8, TFS (&ehdron_tfs), 0x01,
 633       "Extended Header Presence", HFILL}
 634      },
 635     {&hf_docsis_macparm,
 636      {"MacParm", "docsis.macparm",
 637       FT_UINT8, BASE_HEX, NULL, 0x0,
 638       "Mac Parameter Field", HFILL}
 639      },
 640     {&hf_docsis_concat_cnt,
 641      {"Number of Concatenated Frames", "docsis.macparm",
 642       FT_UINT8, BASE_DEC, NULL, 0x0,
 643       NULL, HFILL}
 644      },
 645     {&hf_docsis_ehdrlen,
 646      {"Extended Header Length (bytes)", "docsis.macparm",
 647       FT_UINT8, BASE_DEC, NULL, 0x0,
 648       "Mac Parameter Field", HFILL}
 649      },
 650     {&hf_docsis_lensid,
 651      {"Length after HCS (bytes)", "docsis.lensid",
 652       FT_UINT16, BASE_DEC, NULL, 0x0,
 653       "Length or SID", HFILL}
 654      },
 655     {&hf_docsis_eh_type,
 656      {"Type", "docsis.ehdr.type",
 657       FT_UINT8, BASE_DEC, VALS (eh_type_vals), 0xF0,
 658       "TLV Type", HFILL}
 659      },
 660     {&hf_docsis_eh_len,
 661      {"Length", "docsis.ehdr.len",
 662       FT_UINT8, BASE_DEC, NULL, 0x0F,
 663       "TLV Len", HFILL}
 664      },
 665     {&hf_docsis_eh_val,
 666      {"Value", "docsis.ehdr.value",
 667       FT_BYTES, BASE_NONE, NULL, 0x0,
 668       "TLV Value", HFILL}
 669      },
 670     {&hf_docsis_frag_rsvd,
 671      {"Reserved", "docsis.frag_rsvd",
 672       FT_UINT8, BASE_DEC, NULL, 0xC0,
 673       NULL, HFILL}
 674      },
 675     {&hf_docsis_frag_first,
 676      {"First Frame", "docsis.frag_first",
 677       FT_BOOLEAN, 8, NULL, 0x20,
 678       NULL, HFILL}
 679      },
 680     {&hf_docsis_frag_last,
 681      {"Last Frame", "docsis.frag_last",
 682       FT_BOOLEAN, 8, NULL, 0x10,
 683       NULL, HFILL}
 684      },
 685     {&hf_docsis_frag_seq,
 686      {"Fragmentation Sequence #", "docsis.frag_seq",
 687       FT_UINT8, BASE_DEC, NULL, 0x0F,
 688       "Fragmentation Sequence Number", HFILL}
 689      },
 690     {&hf_docsis_sid,
 691      {"SID", "docsis.ehdr.sid",
 692       FT_UINT16, BASE_DEC, NULL, 0x3FFF,
 693       "Service Identifier", HFILL}
 694      },
 695     {&hf_docsis_said,
 696      {"SAID", "docsis.ehdr.said",
 697       FT_UINT16, BASE_DEC, NULL, 0x3FFF,
 698       "Security Association Identifier", HFILL}
 699      },
 700     {&hf_docsis_reserved,
 701      {"Reserved", "docsis.ehdr.rsvd",
 702       FT_UINT8, BASE_HEX, NULL, 0x3FFF,
 703       "Reserved Byte", HFILL}
 704      },
 705     {&hf_docsis_mini_slots,
 706      {"MiniSlots", "docsis.ehdr.minislots",
 707       FT_UINT8, BASE_DEC, NULL, 0x0,
 708       "Mini Slots Requested", HFILL}
 709      },
 710     {&hf_docsis_key_seq,
 711      {"Key Sequence", "docsis.ehdr.keyseq",
 712       FT_UINT8, BASE_DEC, NULL, 0xF0,
 713       NULL, HFILL}
 714      },
 715     {&hf_docsis_ehdr_ver,
 716      {"Version", "docsis.ehdr.ver",
 717       FT_UINT8, BASE_DEC, NULL, 0x0F,
 718       NULL, HFILL}
 719      },
 720     {&hf_docsis_ehdr_phsi,
 721      {"Payload Header Suppression Index", "docsis.ehdr.phsi",
 722       FT_UINT8, BASE_DEC, NULL, 0x0,
 723       NULL, HFILL}
 724      },
 725     {&hf_docsis_ehdr_qind,
 726      {"Queue Indicator", "docsis.ehdr.qind",
 727       FT_BOOLEAN, 8, TFS(&qind_tfs), 0x80,
 728       NULL, HFILL}
 729      },
 730     {&hf_docsis_ehdr_grants,
 731      {"Active Grants", "docsis.ehdr.act_grants",
 732       FT_UINT8, BASE_DEC, NULL, 0x7F,
 733       NULL, HFILL}
 734      },
 735     {&hf_docsis_ehdr_bpup2_key_seq,
 736      {"Key Sequence", "docsis.ehdr.bpup2_keyseq",
 737       FT_UINT8, BASE_DEC, NULL, 0xF0,
 738       "NULL", HFILL}
 739      },
 740     {&hf_docsis_ehdr_bpup2_ver,
 741      {"Version", "docsis.ehdr.bpup2_ver",
 742       FT_UINT8, BASE_DEC, NULL, 0x0F,
 743       "NULL", HFILL}
 744      },
 745     {&hf_docsis_ehdr_bpup2_bpi_en,
 746      {"Encryption", "docsis.ehdr.bpup2_bpi_en",
 747       FT_BOOLEAN, 8, TFS (&ena_dis_tfs), 0x80,
 748       "BPI Enable", HFILL},
 749      },
 750     {&hf_docsis_ehdr_bpup2_toggle_bit,
 751      {"Toggle", "docsis.ehdr.bpup2_toggle_bit",
 752       FT_BOOLEAN, 8, TFS (&odd_even_tfs), 0x40,
 753       "NULL", HFILL},
 754      },
 755     {&hf_docsis_ehdr_bpup2_sid,
 756      {"SID", "docsis.ehdr.bpup2_sid",
 757       FT_UINT16, BASE_DEC, NULL, 0x3FFF,
 758       "Service Identifier", HFILL}
 759      },
 760     {&hf_docsis_ehdr_ds_traffic_pri,
 761      {"DS Traffic Priority", "docsis.ehdr.ds_traffic_pri",
 762       FT_UINT8, BASE_DEC, NULL, 0xE0,
 763       "NULL", HFILL}
 764      },
 765     {&hf_docsis_ehdr_ds_seq_chg_cnt,
 766      {"DS Sequence Change Count", "docsis.ehdr.ds_seq_chg_cnt",
 767       FT_UINT8, BASE_DEC, NULL, 0x10,
 768       "NULL", HFILL}
 769      },
 770     {&hf_docsis_ehdr_ds_dsid,
 771      {"DS DSID", "docsis.ehdr.ds_dsid",
 772       FT_UINT32, BASE_DEC, NULL, 0x0FFFFF,
 773       "NULL", HFILL}
 774      },
 775     {&hf_docsis_ehdr_ds_pkt_seq_num,
 776      {"DS Packet Sequence Number", "docsis.ehdr.ds_pkt_seq_num",
 777       FT_UINT16, BASE_DEC, NULL, 0x0,
 778       "NULL", HFILL}
 779      },
 780     {&hf_docsis_hcs,
 781      {"Header check sequence", "docsis.hcs",
 782       FT_UINT16, BASE_HEX, NULL, 0x0,
 783       NULL, HFILL},
 784      },
 785     {&hf_docsis_bpi_en,
 786      {"Encryption", "docsis.bpi_en",
 787       FT_BOOLEAN, 8, TFS (&ena_dis_tfs), 0x80,
 788       "BPI Enable", HFILL},
 789      },
 790     {&hf_docsis_toggle_bit,
 791      {"Toggle", "docsis.toggle_bit",
 792       FT_BOOLEAN, 8, TFS (&odd_even_tfs), 0x40,
 793       NULL, HFILL},
 794      },
 795
 796   };
 797
 798 /* Setup protocol subtree array */
 799   static gint *ett[] = {
 800     &ett_docsis,
 801     &ett_ehdr,
 802   };
 803
 804 #if 0
 805   docsis_dissector_table = register_dissector_table ("docsis",
 806                                                      "DOCSIS Encapsulation Type",
 807                                                      FT_UINT8, BASE_DEC);
 808 #endif
 809
 810 /* Register the protocol name and description */
 811   proto_docsis = proto_register_protocol ("DOCSIS 1.1", "DOCSIS", "docsis");
 812
 813 /* Required function calls to register the header fields and subtrees used */
 814   proto_register_field_array (proto_docsis, hf, array_length (hf));
 815   proto_register_subtree_array (ett, array_length (ett));
 816
 817   register_dissector ("docsis", dissect_docsis, proto_docsis);
 818 }
 819
 820
 821 /* If this dissector uses sub-dissector registration add a registration routine.
 822    This format is required because a script is used to find these routines and
 823    create the code that calls these routines.
 824 */
 825 void
 826 proto_reg_handoff_docsis (void)
 827 {
 828
 829   docsis_handle = find_dissector ("docsis");
 830   data_handle = find_dissector ("data");
 831   dissector_add_uint ("wtap_encap", WTAP_ENCAP_DOCSIS, docsis_handle);
 832
 833   docsis_mgmt_handle = find_dissector ("docsis_mgmt");
 834   eth_withoutfcs_handle = find_dissector ("eth_withoutfcs");
 835 }