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  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  *
  11  * ToDo:
  12  *
  13  * References:
  14  *
  15  * http://www.techfest.com/networking/wan/frrel.htm
  16  * https://www.broadband-forum.org/technical/download/FRF.1.2/frf1_2.pdf
  17  * http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/frame.htm#xtocid18
  18  * http://www.net.aapt.com.au/techref/lmimess.htm
  19  * http://www.raleigh.ibm.com:80/cgi-bin/bookmgr/BOOKS/EZ305800/1.2.4.4
  20  */
  21
  22
  23 #include "config.h"
  24
  25 #include <epan/packet.h>
  26 #include <epan/nlpid.h>
  27
  28 void proto_register_lmi(void);
  29 void proto_reg_handoff_lmi(void);
  30
  31 static dissector_handle_t lmi_handle;
  32
  33 static int proto_lmi;
  34 static int hf_lmi_call_ref;
  35 static int hf_lmi_msg_type;
  36 static int hf_lmi_inf_ele;
  37 static int hf_lmi_inf_len;
  38
  39 static int hf_lmi_rcd_type;
  40 static int hf_lmi_send_seq;
  41 static int hf_lmi_recv_seq;
  42 static int hf_lmi_dlci_high;
  43 static int hf_lmi_dlci_low;
  44 static int hf_lmi_new;
  45 static int hf_lmi_act;
  46
  47 static int ett_lmi;
  48 static int ett_lmi_ele;
  49
  50 #ifdef _OLD_
  51 /*
  52  * Bits in the address field.
  53  */
  54 #define LMI_CMD 0xf000    /* LMI Command */
  55 #define LMI_SEQ 0x0fff    /* LMI Sequence number */
  56
  57 #endif
  58
  59 static const value_string msg_type_str[] = {
  60     {0x75, "Status Enquiry"},
  61     {0x7D, "Status"},
  62     { 0,   NULL }
  63 };
  64
  65 static const value_string element_type_str[] = {
  66
  67     /*** These are the ANSI values ***/
  68     {0x01, "Report"},
  69     {0x03, "Keep Alive"},
  70     {0x07, "PVC Status"},
  71
  72     /*** These are the ITU values ***/
  73     {0x51, "Report"},
  74     {0x53, "Keep Alive"},
  75     //{0x07, "PVC Status"},
  76
  77     {0,       NULL }
  78 };
  79
  80 static const value_string record_type_str[] = {
  81     {0x00, "Full Status"},
  82     {0x01, "Link Integrity Verification Only"},
  83     {0x02, "Single PVC"},
  84     {0,    NULL }
  85 };
  86
  87 static const value_string pvc_status_new_str[] = {
  88     {0x00, "PVC already present"},
  89     {0x01, "PVC is new"},
  90     {0,    NULL }
  91 };
  92
  93 static const value_string pvc_status_act_str[] = {
  94     {0x00, "PVC is Inactive"},
  95     {0x01, "PVC is Active"},
  96     {0,    NULL }
  97 };
  98
  99 static void
 100 dissect_lmi_report_type(tvbuff_t *tvb, int offset, proto_tree *tree)
 101 {
 102     proto_tree_add_item(tree, hf_lmi_rcd_type, tvb, offset, 1, ENC_NA);
 103 }
 104
 105 static void
 106 dissect_lmi_link_int(tvbuff_t *tvb, int offset, proto_tree *tree)
 107 {
 108     proto_tree_add_item(tree, hf_lmi_send_seq, tvb, offset, 1, ENC_NA);
 109     ++offset;
 110     proto_tree_add_item(tree, hf_lmi_recv_seq, tvb, offset, 1, ENC_NA);
 111
 112 }
 113
 114 static void
 115 dissect_lmi_pvc_status(tvbuff_t *tvb, int offset, proto_tree *tree)
 116 {
 117     proto_tree_add_item(tree, hf_lmi_dlci_high, tvb, offset, 1, ENC_NA);
 118     ++offset;
 119     proto_tree_add_item(tree, hf_lmi_dlci_low, tvb, offset, 1, ENC_NA);
 120     ++offset;
 121     proto_tree_add_item(tree, hf_lmi_new, tvb, offset, 1, ENC_NA);
 122     proto_tree_add_item(tree, hf_lmi_act, tvb, offset, 1, ENC_NA);
 123 }
 124
 125 static int
 126 dissect_lmi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
 127 {
 128     proto_tree    *lmi_tree, *lmi_subtree;
 129     proto_item    *ti;
 130     int           offset = 2, len;
 131     uint8_t       msg_type;
 132     uint8_t       ele_id;
 133
 134     col_set_str(pinfo->cinfo, COL_PROTOCOL, "LMI");
 135     col_clear(pinfo->cinfo, COL_INFO);
 136
 137     ti = proto_tree_add_item(tree, proto_lmi, tvb, 0, 3, ENC_NA);
 138     lmi_tree = proto_item_add_subtree(ti, ett_lmi_ele);
 139
 140     proto_tree_add_item(lmi_tree, hf_lmi_call_ref, tvb, 0, 1, ENC_BIG_ENDIAN);
 141
 142     msg_type = tvb_get_uint8( tvb, 1);
 143     col_add_str(pinfo->cinfo, COL_INFO,
 144             val_to_str(msg_type, msg_type_str, "Unknown message type (0x%02x)"));
 145
 146     proto_tree_add_uint(lmi_tree, hf_lmi_msg_type, tvb, 1, 1, msg_type);
 147
 148     /* Display the LMI elements */
 149     while (tvb_reported_length_remaining(tvb, offset) > 0) {
 150         ele_id = tvb_get_uint8( tvb, offset);
 151         len =  tvb_get_uint8( tvb, offset + 1);
 152
 153         lmi_subtree = proto_tree_add_subtree_format(lmi_tree, tvb, offset, len + 2,
 154                 ett_lmi_ele, NULL, "Information Element: %s",
 155                 val_to_str(ele_id, element_type_str, "Unknown (%u)"));
 156
 157         proto_tree_add_uint(lmi_subtree, hf_lmi_inf_ele, tvb, offset, 1,
 158                 ele_id);
 159         ++offset;
 160         proto_tree_add_uint(lmi_subtree, hf_lmi_inf_len, tvb, offset, 1, len);
 161         ++offset;
 162         if (( ele_id == 1) || (ele_id == 51))
 163             dissect_lmi_report_type( tvb, offset, lmi_subtree);
 164         else if (( ele_id == 3) || (ele_id == 53))
 165             dissect_lmi_link_int( tvb, offset, lmi_subtree);
 166         else if (( ele_id == 7) || (ele_id == 57))
 167             dissect_lmi_pvc_status( tvb, offset, lmi_subtree);
 168         offset += len;
 169     }
 170     return tvb_captured_length(tvb);
 171 }
 172
 173
 174 void
 175 proto_register_lmi(void)
 176 {
 177     static hf_register_info hf[] = {
 178         { &hf_lmi_call_ref,
 179             { "Call reference", "lmi.cmd", FT_UINT8, BASE_HEX, NULL, 0,
 180                 NULL, HFILL }},
 181
 182         { &hf_lmi_msg_type,
 183             { "Message Type", "lmi.msg_type", FT_UINT8, BASE_HEX, VALS(msg_type_str), 0,
 184                 NULL, HFILL }},
 185
 186         { &hf_lmi_inf_ele,
 187             { "Type", "lmi.inf_ele_type", FT_UINT8, BASE_DEC, VALS(element_type_str), 0,
 188                 "Information Element Type", HFILL }},
 189         { &hf_lmi_inf_len,
 190             { "Length", "lmi.inf_ele_len", FT_UINT8, BASE_DEC, NULL, 0,
 191                 "Information Element Length", HFILL }},
 192
 193         { &hf_lmi_rcd_type,
 194             { "Record Type", "lmi.ele_rcd_type", FT_UINT8, BASE_DEC, VALS(record_type_str), 0,
 195                 NULL, HFILL }},
 196         { &hf_lmi_send_seq,
 197             { "Send Seq", "lmi.send_seq", FT_UINT8, BASE_DEC, NULL, 0,
 198                 "Send Sequence", HFILL }},
 199         { &hf_lmi_recv_seq,
 200             { "Recv Seq", "lmi.recv_seq", FT_UINT8, BASE_DEC, NULL, 0,
 201                 "Receive Sequence", HFILL }},
 202         { &hf_lmi_dlci_high,
 203             { "DLCI High", "lmi.dlci_hi", FT_UINT8, BASE_DEC, NULL, 0x3f,
 204                 "DLCI High bits", HFILL }},
 205         { &hf_lmi_dlci_low,
 206             { "DLCI Low", "lmi.dlci_low", FT_UINT8, BASE_DEC, NULL, 0x78,
 207                 "DLCI Low bits", HFILL }},
 208         { &hf_lmi_new,
 209             { "DLCI New", "lmi.dlci_new", FT_UINT8, BASE_DEC, VALS(pvc_status_new_str), 0x08,
 210                 "DLCI New Flag", HFILL }},
 211         { &hf_lmi_act,
 212             { "DLCI Active","lmi.dlci_act", FT_UINT8, BASE_DEC, VALS(pvc_status_act_str), 0x02,
 213                 "DLCI Active Flag", HFILL }},
 214     };
 215     static int *ett[] = {
 216         &ett_lmi,
 217         &ett_lmi_ele,
 218     };
 219     proto_lmi = proto_register_protocol ("Local Management Interface", "LMI", "lmi");
 220     proto_register_field_array (proto_lmi, hf, array_length(hf));
 221     proto_register_subtree_array(ett, array_length(ett));
 222
 223     lmi_handle = register_dissector("lmi", dissect_lmi, proto_lmi);
 224 }
 225
 226 void
 227 proto_reg_handoff_lmi(void)
 228 {
 229     dissector_add_uint("fr.nlpid", NLPID_LMI, lmi_handle);
 230 }
 231
 232
 233 /*
 234  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 235  *
 236  * Local variables:
 237  * c-basic-offset: 4
 238  * tab-width: 8
 239  * indent-tabs-mode: nil
 240  * End:
 241  *
 242  * vi: set shiftwidth=4 tabstop=8 expandtab:
 243  * :indentSize=4:tabSize=8:noTabs=true:
 244  */