epan/dissectors/packet-x29.c

   1 /* packet-x29.c
   2  * Routines for X.29 packet dissection
   3  *
   4  * Wireshark - Network traffic analyzer
   5  * By Gerald Combs <gerald@wireshark.org>
   6  * Copyright 1998 Gerald Combs
   7  *
   8  * SPDX-License-Identifier: GPL-2.0-or-later
   9  */
  10
  11 #include "config.h"
  12
  13 #include <epan/packet.h>
  14 #include <epan/nlpid.h>
  15
  16 void proto_register_x29(void);
  17 void proto_reg_handoff_x29(void);
  18
  19 static dissector_handle_t x29_handle;
  20
  21 static int proto_x29;
  22 static int hf_msg_code;
  23 static int hf_error_type;
  24 static int hf_inv_msg_code;
  25
  26 /* Generated from convert_proto_tree_add_text.pl */
  27 static int hf_x29_pad_message_data;
  28 static int hf_x29_type_reference_value;
  29 static int hf_x29_type_reference;
  30 static int hf_x29_data;
  31 static int hf_x29_type_of_aspect;
  32 static int hf_x29_reselection_message_data;
  33 static int hf_x29_break_value;
  34 static int hf_x29_parameter;
  35 static int hf_x29_value;
  36
  37 static int ett_x29;
  38
  39 /*
  40  * PAD messages.
  41  */
  42 #define SET_MSG                 0x02
  43 #define READ_MSG                0x04
  44 #define SET_AND_READ_MSG        0x06
  45 #define PARAMETER_IND_MSG       0x00
  46 #define INV_TO_CLEAR_MSG        0x01
  47 #define BREAK_IND_MSG           0x03
  48 #define RESELECTION_MSG         0x07
  49 #define ERROR_MSG               0x05
  50 #define RESEL_WITH_TOA_NPI_MSG  0x08
  51
  52 static const value_string message_code_vals[] = {
  53         { SET_MSG,                      "Set" },
  54         { READ_MSG,                     "Read" },
  55         { SET_AND_READ_MSG,             "Set and read" },
  56         { PARAMETER_IND_MSG,            "Parameter indication" },
  57         { INV_TO_CLEAR_MSG,             "Invitation to clear" },
  58         { BREAK_IND_MSG,                "Indication of break" },
  59         { RESELECTION_MSG,              "Reselection" },
  60         { ERROR_MSG,                    "Error" },
  61         { RESEL_WITH_TOA_NPI_MSG,       "Reselection with TOA/NPI" },
  62         { 0,                            NULL }
  63 };
  64
  65 static const value_string error_type_vals[] = {
  66         { 0x00, "Received PAD message contained less than eight bits" },
  67         { 0x02, "Unrecognized message code in received PAD message" },
  68         { 0x04, "Parameter field format was incorrect or incompatible with message code" },
  69         { 0x06, "Received PAD message did not contain an integral number of octets" },
  70         { 0x08, "Received Parameter Indication PAD message was unsolicited" },
  71         { 0x0A, "Received PAD message was too long" },
  72         { 0x0C, "Unauthorized reselection PAD message" },
  73         { 0,    NULL },
  74 };
  75
  76 static const value_string reference_type_vals[] = {
  77         { 0x01, "Change in PAD Aspect" },
  78         { 0x08, "Break" },
  79         { 0,    NULL },
  80 };
  81
  82 static int
  83 dissect_x29(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
  84 {
  85         int         offset = 0;
  86         proto_tree *x29_tree;
  87         proto_item *ti;
  88         bool       *q_bit_set;
  89         uint8_t     msg_code;
  90         uint8_t     error_type;
  91         uint8_t     type_ref;
  92         int         next_offset;
  93         int         linelen;
  94
  95         /* Reject the packet if data is NULL */
  96         if (data == NULL)
  97                 return 0;
  98         q_bit_set = (bool *)data;
  99
 100         col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.29");
 101         col_clear(pinfo->cinfo, COL_INFO);
 102
 103         ti = proto_tree_add_item(tree, proto_x29, tvb, offset, -1, ENC_NA);
 104         x29_tree = proto_item_add_subtree(ti, ett_x29);
 105
 106         if (*q_bit_set) {
 107                 /*
 108                  * Q bit set - this is a PAD message.
 109                  */
 110                 msg_code = tvb_get_uint8(tvb, offset);
 111                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s PAD message",
 112                             val_to_str(msg_code, message_code_vals,
 113                                 "Unknown (0x%02x)"));
 114
 115                 proto_tree_add_uint(x29_tree, hf_msg_code, tvb,
 116                     offset, 1, msg_code);
 117                 offset++;
 118
 119                 switch (msg_code) {
 120
 121                 case SET_MSG:
 122                 case READ_MSG:
 123                 case SET_AND_READ_MSG:
 124                 case PARAMETER_IND_MSG:
 125                         /*
 126                          * XXX - dissect the references as per X.3.
 127                          */
 128                         while (tvb_reported_length_remaining(tvb, offset) > 0) {
 129                                 proto_tree_add_item(x29_tree, hf_x29_parameter, tvb, offset, 1, ENC_BIG_ENDIAN);
 130                                 offset++;
 131                                 proto_tree_add_item(x29_tree, hf_x29_value, tvb, offset, 1, ENC_BIG_ENDIAN);
 132                                 offset++;
 133                         }
 134                         break;
 135
 136                 case INV_TO_CLEAR_MSG:
 137                         /*
 138                          * No data for this message.
 139                          */
 140                         break;
 141
 142                 case ERROR_MSG:
 143                         error_type = tvb_get_uint8(tvb, offset);
 144                         proto_tree_add_uint(x29_tree, hf_error_type, tvb,
 145                             offset, 1, error_type);
 146                         offset++;
 147                         if (error_type != 0) {
 148                                 proto_tree_add_item(x29_tree, hf_inv_msg_code,
 149                                     tvb, offset, 1, ENC_BIG_ENDIAN);
 150                         }
 151                         break;
 152
 153                 case BREAK_IND_MSG:
 154                         if (tvb_reported_length_remaining(tvb, offset) > 0) {
 155                                 type_ref = tvb_get_uint8(tvb, offset);
 156                                 proto_tree_add_item(x29_tree, hf_x29_type_reference, tvb, offset, 1, ENC_BIG_ENDIAN);
 157                                 offset++;
 158                                 switch (type_ref) {
 159
 160                                 case 0x01:      /* change in PAD Aspect */
 161                                         /*
 162                                          * XXX - dissect as per X.28.
 163                                          */
 164                                         proto_tree_add_item(x29_tree, hf_x29_type_of_aspect, tvb, offset, 1, ENC_BIG_ENDIAN);
 165                                         offset++;
 166                                         break;
 167
 168                                 case 0x08:      /* break */
 169                                         proto_tree_add_item(x29_tree, hf_x29_break_value, tvb, offset, 1, ENC_BIG_ENDIAN);
 170                                         offset++;
 171                                         break;
 172
 173                                 default:
 174                                         proto_tree_add_item(x29_tree, hf_x29_type_reference_value, tvb, offset, 1, ENC_BIG_ENDIAN);
 175                                         offset++;
 176                                         break;
 177                                 }
 178                         }
 179                         break;
 180
 181                 case RESELECTION_MSG:
 182                         /*
 183                          * XXX - dissect me.
 184                          */
 185                         proto_tree_add_item(x29_tree, hf_x29_reselection_message_data, tvb, offset, -1, ENC_NA);
 186                         break;
 187
 188                 case RESEL_WITH_TOA_NPI_MSG:
 189                         /*
 190                          * XXX - dissect me.
 191                          */
 192                         proto_tree_add_item(x29_tree, hf_x29_reselection_message_data, tvb, offset, -1, ENC_NA);
 193                         break;
 194
 195                 default:
 196                         proto_tree_add_item(x29_tree, hf_x29_pad_message_data, tvb, offset, -1, ENC_NA);
 197                         break;
 198                 }
 199         } else {
 200                 /*
 201                  * Q bit not set - this is data.
 202                  */
 203                 col_set_str(pinfo->cinfo, COL_INFO, "Data ...");
 204
 205                 if (tree) {
 206                         while (tvb_offset_exists(tvb, offset)) {
 207                                 /*
 208                                  * Find the end of the line.
 209                                  */
 210                                 tvb_find_line_end(tvb, offset, -1,
 211                                     &next_offset, false);
 212
 213                                 /*
 214                                  * Now compute the length of the line
 215                                  * *including* the end-of-line indication,
 216                                  * if any; we display it all.
 217                                  */
 218                                 linelen = next_offset - offset;
 219
 220                                 proto_tree_add_item(x29_tree, hf_x29_data, tvb, offset, linelen, ENC_NA|ENC_ASCII);
 221                                 offset = next_offset;
 222                         }
 223                 }
 224         }
 225
 226         return tvb_captured_length(tvb);
 227 }
 228
 229 void
 230 proto_register_x29(void)
 231 {
 232         static hf_register_info hf[] = {
 233             { &hf_msg_code,
 234                 { "Message code", "x29.msg_code", FT_UINT8, BASE_HEX,
 235                   VALS(message_code_vals), 0x0, "X.29 PAD message code",
 236                   HFILL }},
 237             { &hf_error_type,
 238                 { "Error type", "x29.error_type", FT_UINT8, BASE_HEX,
 239                   VALS(error_type_vals), 0x0, "X.29 error PAD message error type",
 240                   HFILL }},
 241             { &hf_inv_msg_code,
 242                 { "Invalid message code", "x29.inv_msg_code", FT_UINT8, BASE_HEX,
 243                   VALS(message_code_vals), 0x0, "X.29 Error PAD message invalid message code",
 244                   HFILL }},
 245
 246                 /* Generated from convert_proto_tree_add_text.pl */
 247                 { &hf_x29_type_reference, { "Type reference", "x29.type_reference", FT_UINT8, BASE_DEC, VALS(reference_type_vals), 0x0, NULL, HFILL }},
 248                 { &hf_x29_type_of_aspect, { "Type of aspect", "x29.type_of_aspect", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }},
 249                 { &hf_x29_break_value, { "Break value", "x29.break_value", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }},
 250                 { &hf_x29_type_reference_value, { "Type value", "x29.type_reference.value", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }},
 251                 { &hf_x29_reselection_message_data, { "Reselection message data", "x29.reselection_message_data", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},
 252                 { &hf_x29_pad_message_data, { "PAD message data", "x29.pad_message_data", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},
 253                 { &hf_x29_data, { "Data", "x29.data", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL }},
 254                 { &hf_x29_parameter, { "Parameter", "x29.parameter", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},
 255                 { &hf_x29_value, { "Value", "x29.value", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},
 256         };
 257         static int *ett[] = {
 258                 &ett_x29,
 259         };
 260
 261         proto_x29 = proto_register_protocol("X.29", "X.29", "x29");
 262         x29_handle = register_dissector("x29", dissect_x29, proto_x29);
 263         proto_register_field_array(proto_x29, hf, array_length(hf));
 264         proto_register_subtree_array(ett, array_length(ett));
 265 }
 266
 267 void
 268 proto_reg_handoff_x29(void)
 269 {
 270         dissector_add_uint("x.25.spi", NLPID_SPI_X_29, x29_handle);
 271 }
 272
 273 /*
 274  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 275  *
 276  * Local variables:
 277  * c-basic-offset: 8
 278  * tab-width: 8
 279  * indent-tabs-mode: t
 280  * End:
 281  *
 282  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 283  * :indentSize=8:tabSize=8:noTabs=false:
 284  */