epan/dissectors/packet-lmi.c

   1 /* packet-lmi.c
   2  * Routines for Frame Relay Local Management Interface (LMI) disassembly
   3  * Copyright 2001, Jeffrey C. Foster <jfoste@woodward.com>
   4  *
   5  * $Id$
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 1998
  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  * ToDo:
  26  *
  27  * References:
  28  *
  29  * http://www.techfest.com/networking/wan/frrel.htm
  30  * http://www.frforum.com/5000/Approved/FRF.1.2/frf1_2.pdf
  31  * http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/frame.htm#xtocid18
  32  * http://www.net.aapt.com.au/techref/lmimess.htm
  33  * http://www.raleigh.ibm.com:80/cgi-bin/bookmgr/BOOKS/EZ305800/1.2.4.4
  34  */
  35
  36
  37 #include "config.h"
  38
  39 #include <glib.h>
  40 #include <epan/packet.h>
  41 #include <epan/nlpid.h>
  42
  43 static int proto_lmi = -1;
  44 static int hf_lmi_call_ref = -1;
  45 static int hf_lmi_msg_type = -1;
  46 static int hf_lmi_inf_ele = -1;
  47 static int hf_lmi_inf_len = -1;
  48
  49 static int hf_lmi_rcd_type = -1;
  50 static int hf_lmi_send_seq = -1;
  51 static int hf_lmi_recv_seq = -1;
  52 static int hf_lmi_dlci_high = -1;
  53 static int hf_lmi_dlci_low = -1;
  54 static int hf_lmi_new = -1;
  55 static int hf_lmi_act = -1;
  56
  57 static gint ett_lmi = -1;
  58 static gint ett_lmi_ele = -1;
  59
  60 #ifdef _OLD_
  61 /*
  62  * Bits in the address field.
  63  */
  64 #define LMI_CMD         0xf000  /* LMI Command */
  65 #define LMI_SEQ         0x0fff  /* LMI Sequence number */
  66
  67 #endif
  68
  69 static const value_string msg_type_str[] = {
  70         {0x75, "Status Enquiry"},
  71         {0x7D, "Status"},
  72         { 0,       NULL }
  73         };
  74
  75 static const value_string element_type_str[] = {
  76
  77 /*** These are the ANSI values ***/
  78         {0x01, "Report"},
  79         {0x03, "Keep Alive"},
  80         {0x07, "PVC Status"},
  81
  82 /*** These are the ITU values ***/
  83         {0x51, "Report"},
  84         {0x53, "Keep Alive"},
  85         {0x07, "PVC Status"},
  86
  87         { 0,       NULL }
  88         };
  89
  90 static const value_string record_type_str[] = {
  91         {0x00, "Full Status"},
  92         {0x01, "Link Integrity Verification Only"},
  93         {0x02, "Single PVC"},
  94         { 0,       NULL }
  95         };
  96
  97 static const value_string pvc_status_new_str[] = {
  98         {0x00, "PVC already present"},
  99         {0x01, "PVC is new"},
 100         { 0,       NULL }
 101         };
 102
 103 static const value_string pvc_status_act_str[] = {
 104         {0x00, "PVC is Inactive"},
 105         {0x01, "PVC is Active"},
 106         { 0,       NULL }
 107         };
 108
 109 static void
 110 dissect_lmi_report_type(tvbuff_t *tvb, int offset, proto_tree *tree)
 111 {
 112         proto_tree_add_uint(tree, hf_lmi_rcd_type, tvb, offset, 1, tvb_get_guint8( tvb, offset));
 113 }
 114
 115 static void
 116 dissect_lmi_link_int(tvbuff_t *tvb, int offset, proto_tree *tree)
 117 {
 118         proto_tree_add_uint(tree, hf_lmi_send_seq, tvb, offset, 1, tvb_get_guint8( tvb, offset));
 119         ++offset;
 120         proto_tree_add_uint(tree, hf_lmi_recv_seq, tvb, offset, 1, tvb_get_guint8( tvb, offset));
 121
 122 }
 123
 124 static void
 125 dissect_lmi_pvc_status(tvbuff_t *tvb, int offset, proto_tree *tree)
 126 {
 127         proto_tree_add_uint(tree, hf_lmi_dlci_high, tvb, offset, 1, tvb_get_guint8( tvb, offset));
 128         ++offset;
 129         proto_tree_add_uint(tree, hf_lmi_dlci_low, tvb, offset, 1, tvb_get_guint8( tvb, offset));
 130         ++offset;
 131         proto_tree_add_uint(tree, hf_lmi_new, tvb, offset, 1, tvb_get_guint8( tvb, offset));
 132         proto_tree_add_uint(tree, hf_lmi_act, tvb, offset, 1, tvb_get_guint8( tvb, offset));
 133 }
 134
 135 static void
 136 dissect_lmi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 137 {
 138         proto_tree      *lmi_tree = NULL, *lmi_subtree;
 139         proto_item      *ti;
 140         int             offset = 2, len;
 141         guint8          msg_type;
 142         guint8          ele_id;
 143
 144         col_set_str(pinfo->cinfo, COL_PROTOCOL, "LMI");
 145         col_clear(pinfo->cinfo, COL_INFO);
 146
 147         if (tree) {
 148                 ti = proto_tree_add_item(tree, proto_lmi, tvb, 0, 3, ENC_NA);
 149                 lmi_tree = proto_item_add_subtree(ti, ett_lmi_ele);
 150
 151                 proto_tree_add_item(lmi_tree, hf_lmi_call_ref, tvb, 0, 1, ENC_BIG_ENDIAN);
 152         }
 153         msg_type = tvb_get_guint8( tvb, 1);
 154         col_add_str(pinfo->cinfo, COL_INFO,
 155                     val_to_str(msg_type, msg_type_str, "Unknown message type (0x%02x)"));
 156
 157         if (tree) {
 158                 proto_tree_add_uint(lmi_tree, hf_lmi_msg_type, tvb, 1, 1, msg_type);
 159
 160         /* Display the LMI elements */
 161                 while (tvb_reported_length_remaining(tvb, offset) > 0) {
 162                         ele_id = tvb_get_guint8( tvb, offset);
 163                         len =  tvb_get_guint8( tvb, offset + 1);
 164
 165                         ti = proto_tree_add_text(lmi_tree, tvb, offset, len + 2,
 166                                 "Information Element: %s",
 167                                 val_to_str(ele_id, element_type_str, "Unknown (%u)"));
 168
 169                         lmi_subtree = proto_item_add_subtree(ti, ett_lmi_ele);
 170
 171                         proto_tree_add_uint(lmi_subtree, hf_lmi_inf_ele, tvb, offset, 1,
 172                                 ele_id);
 173                         ++offset;
 174                         proto_tree_add_uint(lmi_subtree, hf_lmi_inf_len, tvb, offset, 1, len);
 175                         ++offset;
 176                         if (( ele_id == 1) || (ele_id == 51))
 177                                 dissect_lmi_report_type( tvb, offset, lmi_subtree);
 178                         else if (( ele_id == 3) || (ele_id == 53))
 179                                 dissect_lmi_link_int( tvb, offset, lmi_subtree);
 180                         else if (( ele_id == 7) || (ele_id == 57))
 181                                 dissect_lmi_pvc_status( tvb, offset, lmi_subtree);
 182                         offset += len;
 183                 }
 184         }
 185         else {
 186                 lmi_tree = NULL;
 187         }
 188 }
 189
 190
 191 void
 192 proto_register_lmi(void)
 193 {
 194     static hf_register_info hf[] = {
 195         { &hf_lmi_call_ref,
 196           { "Call reference", "lmi.cmd", FT_UINT8, BASE_HEX, NULL, 0,
 197                 NULL, HFILL }},
 198
 199         { &hf_lmi_msg_type,
 200           { "Message Type", "lmi.msg_type", FT_UINT8, BASE_HEX, VALS(msg_type_str), 0,
 201                 NULL, HFILL }},
 202
 203         { &hf_lmi_inf_ele,
 204           { "Type", "lmi.inf_ele_type", FT_UINT8, BASE_DEC, VALS(element_type_str), 0,
 205                 "Information Element Type", HFILL }},
 206         { &hf_lmi_inf_len,
 207           { "Length", "lmi.inf_ele_len", FT_UINT8, BASE_DEC, NULL, 0,
 208                 "Information Element Length", HFILL }},
 209
 210         { &hf_lmi_rcd_type,
 211           { "Record Type", "lmi.ele_rcd_type", FT_UINT8, BASE_DEC, VALS(record_type_str), 0,
 212                 NULL, HFILL }},
 213         { &hf_lmi_send_seq,
 214           { "Send Seq", "lmi.send_seq", FT_UINT8, BASE_DEC, NULL, 0,
 215                 "Send Sequence", HFILL }},
 216         { &hf_lmi_recv_seq,
 217           { "Recv Seq", "lmi.recv_seq", FT_UINT8, BASE_DEC, NULL, 0,
 218                 "Receive Sequence", HFILL }},
 219         { &hf_lmi_dlci_high,
 220           { "DLCI High", "lmi.dlci_hi", FT_UINT8, BASE_DEC, NULL, 0x3f,
 221                 "DLCI High bits", HFILL }},
 222         { &hf_lmi_dlci_low,
 223           { "DLCI Low", "lmi.dlci_low", FT_UINT8, BASE_DEC, NULL, 0x78,
 224                 "DLCI Low bits", HFILL }},
 225         { &hf_lmi_new,
 226           { "DLCI New", "lmi.dlci_new", FT_UINT8, BASE_DEC, VALS(pvc_status_new_str), 0x08,
 227                 "DLCI New Flag", HFILL }},
 228         { &hf_lmi_act,
 229           { "DLCI Active","lmi.dlci_act", FT_UINT8, BASE_DEC, VALS(pvc_status_act_str), 0x02,
 230                 "DLCI Active Flag", HFILL }},
 231     };
 232     static gint *ett[] = {
 233         &ett_lmi,
 234         &ett_lmi_ele,
 235     };
 236     proto_lmi = proto_register_protocol ("Local Management Interface", "LMI", "lmi");
 237     proto_register_field_array (proto_lmi, hf, array_length(hf));
 238     proto_register_subtree_array(ett, array_length(ett));
 239
 240 }
 241
 242 void
 243 proto_reg_handoff_lmi(void)
 244 {
 245         dissector_handle_t lmi_handle;
 246
 247         lmi_handle = create_dissector_handle(dissect_lmi, proto_lmi);
 248         dissector_add_uint("fr.ietf", NLPID_LMI, lmi_handle);
 249 }