plugins/docsis/packet-dccrsp.c

   1 /* packet-dccrsp.c
   2  * Routines for DCC Response Message  dissection
   3  * Copyright 2004, Darryl Hymel <darryl.hymel[AT]arrisi.com>
   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 #include "config.h"
  27
  28 #include <epan/packet.h>
  29 #include <epan/exceptions.h>
  30
  31 #define DCCRSP_CM_JUMP_TIME 1
  32 #define DCCRSP_KEY_SEQ_NUM 31
  33 #define DCCRSP_HMAC_DIGEST 27
  34
  35 /* Define DCC-RSP CM Jump Time subtypes
  36  * These are subtype of DCCRSP_CM_JUMP_TIME (1)
  37  */
  38 #define DCCRSP_CM_JUMP_TIME_LENGTH 1
  39 #define DCCRSP_CM_JUMP_TIME_START 2
  40
  41 /* Initialize the protocol and registered fields */
  42 static int proto_docsis_dccrsp = -1;
  43
  44 static int hf_docsis_dccrsp_tran_id = -1;
  45 static int hf_docsis_dccrsp_conf_code = -1;
  46 static int hf_docsis_dccrsp_cm_jump_time_length = -1;
  47 static int hf_docsis_dccrsp_cm_jump_time_start = -1;
  48 static int hf_docsis_dccrsp_key_seq_num = -1;
  49 static int hf_docsis_dccrsp_hmac_digest = -1;
  50
  51 /* Initialize the subtree pointers */
  52 static gint ett_docsis_dccrsp = -1;
  53 static gint ett_docsis_dccrsp_cm_jump_time = -1;
  54
  55
  56 /* Code to actually dissect the packets */
  57 static void
  58 dissect_dccrsp_cm_jump_time (tvbuff_t * tvb, proto_tree * tree, int start, guint16 len)
  59 {
  60   guint8 type, length;
  61   proto_item *dcc_item;
  62   proto_tree *dcc_tree;
  63   int pos;
  64
  65   pos = start;
  66   dcc_item = proto_tree_add_text ( tree, tvb, start, len, "2 DCC-RSP CM Time Jump Encodings (Length = %u)", len);
  67   dcc_tree = proto_item_add_subtree ( dcc_item , ett_docsis_dccrsp_cm_jump_time);
  68
  69   while ( pos < ( start + len) )
  70     {
  71         type = tvb_get_guint8 (tvb, pos++);
  72         length = tvb_get_guint8 (tvb, pos++);
  73
  74         switch (type)
  75           {
  76             case DCCRSP_CM_JUMP_TIME_LENGTH:
  77               if (length == 4)
  78                 {
  79                   proto_tree_add_item (dcc_tree, hf_docsis_dccrsp_cm_jump_time_length, tvb,
  80                                        pos, length, ENC_BIG_ENDIAN);
  81                 }
  82               else
  83                 {
  84                   THROW (ReportedBoundsError);
  85                 }
  86               break;
  87             case DCCRSP_CM_JUMP_TIME_START:
  88               if (length == 8)
  89                 {
  90                   proto_tree_add_item (dcc_tree, hf_docsis_dccrsp_cm_jump_time_start, tvb,
  91                                    pos, length, ENC_BIG_ENDIAN);
  92                 }
  93               else
  94                 {
  95                   THROW (ReportedBoundsError);
  96                 }
  97               break;
  98             }
  99           pos = pos + length;
 100       }
 101 }
 102 static void
 103 dissect_dccrsp (tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 104 {
 105   guint16 pos;
 106   guint8 type, length;
 107   proto_tree *dcc_tree;
 108   proto_item *dcc_item;
 109   guint16 len;
 110
 111   len = tvb_length_remaining (tvb, 0);
 112
 113   col_set_str(pinfo->cinfo, COL_INFO, "DCC-RSP Message: ");
 114
 115   if (tree)
 116     {
 117       dcc_item =
 118         proto_tree_add_protocol_format (tree, proto_docsis_dccrsp, tvb, 0,
 119                                         tvb_length_remaining (tvb, 0),
 120                                         "DCC-RSP Message");
 121       dcc_tree = proto_item_add_subtree (dcc_item, ett_docsis_dccrsp);
 122       proto_tree_add_item (dcc_tree, hf_docsis_dccrsp_tran_id, tvb, 0, 2, ENC_BIG_ENDIAN);
 123       proto_tree_add_item (dcc_tree, hf_docsis_dccrsp_conf_code, tvb, 2, 1, ENC_BIG_ENDIAN);
 124
 125       pos = 3;
 126       while (pos < len)
 127         {
 128           type = tvb_get_guint8 (tvb, pos++);
 129           length = tvb_get_guint8 (tvb, pos++);
 130           switch (type)
 131             {
 132             case DCCRSP_CM_JUMP_TIME:
 133               dissect_dccrsp_cm_jump_time (tvb , dcc_tree , pos , length );
 134               break;
 135             case DCCRSP_KEY_SEQ_NUM:
 136               if (length == 1)
 137                 {
 138                   proto_tree_add_item (dcc_tree, hf_docsis_dccrsp_key_seq_num, tvb,
 139                                        pos, length, ENC_BIG_ENDIAN);
 140                 }
 141               else
 142                 {
 143                   THROW (ReportedBoundsError);
 144                 }
 145               break;
 146             case DCCRSP_HMAC_DIGEST:
 147               if (length == 20)
 148                 {
 149                   proto_tree_add_item (dcc_tree, hf_docsis_dccrsp_hmac_digest, tvb,
 150                                        pos, length, ENC_NA);
 151                 }
 152               else
 153                 {
 154                   THROW (ReportedBoundsError);
 155                 }
 156               break;
 157             }                   /* switch(type) */
 158           pos = pos + length;
 159         }                       /* while (pos < len) */
 160     }                           /* if (tree) */
 161
 162 }
 163 /* Register the protocol with Wireshark */
 164
 165 /* this format is require because a script is used to build the C function
 166    that calls all the protocol registration.
 167 */
 168
 169
 170 void
 171 proto_register_docsis_dccrsp (void)
 172 {
 173 /* Setup list of header fields  See Section 1.6.1 for details*/
 174   static hf_register_info hf[] = {
 175     {&hf_docsis_dccrsp_tran_id ,
 176       {
 177       "Transaction ID",
 178       "docsis_dccrsp.tran_id",
 179       FT_UINT16, BASE_DEC, NULL, 0x0,
 180       NULL,
 181       HFILL
 182       }
 183     },
 184     {&hf_docsis_dccrsp_conf_code ,
 185       {
 186       "Confirmation Code",
 187       "docsis_dccrsp.conf_code",
 188       FT_UINT8, BASE_DEC, NULL, 0x0,
 189       NULL,
 190       HFILL
 191       }
 192     },
 193     {&hf_docsis_dccrsp_cm_jump_time_length ,
 194       {
 195       "Jump Time Length",
 196       "docsis_dccrsp.cm_jump_time_length",
 197       FT_UINT32, BASE_DEC, NULL, 0x0,
 198       NULL,
 199       HFILL
 200       }
 201     },
 202     {&hf_docsis_dccrsp_cm_jump_time_start ,
 203       {
 204       "Jump Time Start",
 205       "docsis_dccrsp.cm_jump_time_start",
 206       FT_UINT64, BASE_DEC, NULL, 0x0,
 207       NULL,
 208       HFILL
 209       }
 210     },
 211     {&hf_docsis_dccrsp_key_seq_num ,
 212       {
 213       "Auth Key Sequence Number",
 214       "docsis_dccrsp.key_seq_num",
 215       FT_UINT8, BASE_DEC, NULL, 0x0,
 216       NULL,
 217       HFILL
 218       }
 219     },
 220     {&hf_docsis_dccrsp_hmac_digest ,
 221       {
 222       "HMAC-DigestNumber",
 223       "docsis_dccrsp.hmac_digest",
 224       FT_BYTES, BASE_NONE, NULL, 0x0,
 225       NULL,
 226       HFILL
 227       }
 228     },
 229
 230   };
 231
 232 /* Setup protocol subtree array */
 233   static gint *ett[] = {
 234     &ett_docsis_dccrsp,
 235     &ett_docsis_dccrsp_cm_jump_time,
 236   };
 237
 238 /* Register the protocol name and description */
 239   proto_docsis_dccrsp =
 240     proto_register_protocol ("DOCSIS Downstream Channel Change Response",
 241                              "DOCSIS DCC-RSP", "docsis_dccrsp");
 242
 243 /* Required function calls to register the header fields and subtrees used */
 244   proto_register_field_array (proto_docsis_dccrsp, hf, array_length (hf));
 245   proto_register_subtree_array (ett, array_length (ett));
 246
 247   register_dissector ("docsis_dccrsp", dissect_dccrsp, proto_docsis_dccrsp);
 248 }
 249
 250
 251 /* If this dissector uses sub-dissector registration add a registration routine.
 252    This format is required because a script is used to find these routines and
 253    create the code that calls these routines.
 254 */
 255 void
 256 proto_reg_handoff_docsis_dccrsp (void)
 257 {
 258   dissector_handle_t docsis_dccrsp_handle;
 259
 260   docsis_dccrsp_handle = find_dissector ("docsis_dccrsp");
 261   dissector_add_uint ("docsis_mgmt", 0x18, docsis_dccrsp_handle);
 262
 263 }