epan/dissectors/packet-v120.c

   1 /* packet-v120.c
   2  * Routines for v120 frame disassembly
   3  * Bert Driehuis <driehuis@playbeing.org>
   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
  12 #include "config.h"
  13
  14 #include <epan/packet.h>
  15 #include <epan/xdlc.h>
  16 #include <epan/tfs.h>
  17 #include <wsutil/array.h>
  18
  19 void proto_register_v120(void);
  20
  21 static int proto_v120;
  22 static int hf_v120_address;
  23 static int hf_v120_rc;
  24 static int hf_v120_lli;
  25 static int hf_v120_ea0;
  26 static int hf_v120_ea1;
  27 static int hf_v120_control;
  28 static int hf_v120_n_r;
  29 static int hf_v120_n_s;
  30 static int hf_v120_p;
  31 static int hf_v120_p_ext;
  32 static int hf_v120_f;
  33 static int hf_v120_f_ext;
  34 static int hf_v120_s_ftype;
  35 static int hf_v120_u_modifier_cmd;
  36 static int hf_v120_u_modifier_resp;
  37 static int hf_v120_ftype_i;
  38 static int hf_v120_ftype_s_u;
  39 static int hf_v120_ftype_s_u_ext;
  40 static int hf_v120_header8;
  41 static int hf_v120_header_ext8;
  42 static int hf_v120_header_break8;
  43 static int hf_v120_header_error_control8;
  44 static int hf_v120_header_segb8;
  45 static int hf_v120_header_segf8;
  46 static int hf_v120_header16;
  47 static int hf_v120_header_ext16;
  48 static int hf_v120_header_break16;
  49 static int hf_v120_header_error_control16;
  50 static int hf_v120_header_segb16;
  51 static int hf_v120_header_segf16;
  52 static int hf_v120_header_e;
  53 static int hf_v120_header_dr;
  54 static int hf_v120_header_sr;
  55 static int hf_v120_header_rr;
  56
  57 static int ett_v120;
  58 static int ett_v120_address;
  59 static int ett_v120_control;
  60 static int ett_v120_header;
  61
  62 static int dissect_v120_header(tvbuff_t *tvb, int offset, proto_tree *tree);
  63
  64 /* Used only for U frames */
  65 static const xdlc_cf_items v120_cf_items = {
  66         NULL,
  67         NULL,
  68         &hf_v120_p,
  69         &hf_v120_f,
  70         NULL,
  71         &hf_v120_u_modifier_cmd,
  72         &hf_v120_u_modifier_resp,
  73         NULL,
  74         &hf_v120_ftype_s_u
  75 };
  76
  77 /* Used only for I and S frames */
  78 static const xdlc_cf_items v120_cf_items_ext = {
  79         &hf_v120_n_r,
  80         &hf_v120_n_s,
  81         &hf_v120_p_ext,
  82         &hf_v120_f_ext,
  83         &hf_v120_s_ftype,
  84         NULL,
  85         NULL,
  86         &hf_v120_ftype_i,
  87         &hf_v120_ftype_s_u_ext
  88 };
  89
  90 static int
  91 dissect_v120(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  92 {
  93         proto_tree *v120_tree, *address_tree;
  94         proto_item *ti, *tc;
  95         int         is_response;
  96         int         v120len;
  97         uint8_t     byte0, byte1;
  98         uint16_t    control;
  99         tvbuff_t   *next_tvb;
 100
 101         col_set_str(pinfo->cinfo, COL_PROTOCOL, "V.120");
 102         col_clear(pinfo->cinfo, COL_INFO);
 103
 104         byte0 = tvb_get_uint8(tvb, 0);
 105
 106         col_add_fstr(pinfo->cinfo, COL_RES_DL_SRC, "0x%02X", byte0);
 107
 108         byte1 = tvb_get_uint8(tvb, 1);
 109
 110         if ( ((byte0 & 0x01) != 0x00) && ((byte1 & 0x01) != 0x01) )
 111         {
 112                 col_set_str(pinfo->cinfo, COL_INFO, "Invalid V.120 frame");
 113                 if (tree)
 114                         proto_tree_add_protocol_format(tree, proto_v120, tvb, 0, -1,
 115                                                                         "Invalid V.120 frame");
 116                 return 2;
 117         }
 118
 119         if (pinfo->p2p_dir == P2P_DIR_SENT) {
 120                 is_response = (byte0 & 0x02) ? false: true;
 121                 col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE");
 122                 col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE");
 123         } else {
 124                 /* XXX - what if the direction is unknown? */
 125                 is_response = (byte0 & 0x02) ? true : false;
 126                 col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE");
 127                 col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE");
 128         }
 129
 130         ti = proto_tree_add_protocol_format(tree, proto_v120, tvb, 0, -1, "V.120");
 131         v120_tree = proto_item_add_subtree(ti, ett_v120);
 132         tc = proto_tree_add_item(v120_tree, hf_v120_address, tvb, 0, 2, ENC_BIG_ENDIAN);
 133         proto_item_append_text(tc, "LLI: %d C/R: %s",
 134                         ((byte0 & 0xfc) << 5) | ((byte1 & 0xfe) >> 1),
 135                         byte0 & 0x02 ? "R" : "C");
 136         address_tree = proto_item_add_subtree(tc, ett_v120_address);
 137
 138         proto_tree_add_item(address_tree, hf_v120_rc, tvb, 0, 2, ENC_BIG_ENDIAN);
 139         proto_tree_add_item(address_tree, hf_v120_lli, tvb, 0, 2, ENC_BIG_ENDIAN);
 140         proto_tree_add_item(address_tree, hf_v120_ea0, tvb, 0, 2, ENC_BIG_ENDIAN);
 141         proto_tree_add_item(address_tree, hf_v120_ea1, tvb, 0, 2, ENC_BIG_ENDIAN);
 142
 143         control = dissect_xdlc_control(tvb, 2, pinfo, v120_tree, hf_v120_control,
 144                 ett_v120_control, &v120_cf_items, &v120_cf_items_ext,
 145                 NULL, NULL, is_response, true, false);
 146
 147         v120len = 2 + XDLC_CONTROL_LEN(control, true);
 148
 149         if (tvb_bytes_exist(tvb, v120len, 1))
 150                 v120len += dissect_v120_header(tvb, v120len, v120_tree);
 151         proto_item_set_len(ti, v120len);
 152         next_tvb = tvb_new_subset_remaining(tvb, v120len);
 153         call_data_dissector(next_tvb, pinfo, v120_tree);
 154
 155         return tvb_captured_length(tvb);
 156 }
 157
 158 static int
 159 dissect_v120_header(tvbuff_t *tvb, int offset, proto_tree *tree)
 160 {
 161         int         header_len;
 162         uint8_t     byte0;
 163         proto_tree *h_tree;
 164         proto_item *tc;
 165
 166         byte0 = tvb_get_uint8(tvb, offset);
 167         if (byte0 & 0x80) {
 168                 header_len = 1;
 169                 tc = proto_tree_add_item(tree, hf_v120_header8, tvb, 0, 1, ENC_BIG_ENDIAN);
 170
 171                 h_tree = proto_item_add_subtree(tc, ett_v120_header);
 172                 proto_tree_add_item(h_tree, hf_v120_header_ext8, tvb, 0, 1, ENC_NA);
 173                 proto_tree_add_item(h_tree, hf_v120_header_break8, tvb, 0, 1, ENC_NA);
 174                 proto_tree_add_item(h_tree, hf_v120_header_error_control8, tvb, 0, 1, ENC_BIG_ENDIAN);
 175                 proto_tree_add_item(h_tree, hf_v120_header_segb8, tvb, 0, 1, ENC_NA);
 176                 proto_tree_add_item(h_tree, hf_v120_header_segf8, tvb, 0, 1, ENC_NA);
 177         } else {
 178                 header_len = 2;
 179                 tc = proto_tree_add_item(tree, hf_v120_header16, tvb, 0, 2, ENC_BIG_ENDIAN);
 180                 h_tree = proto_item_add_subtree(tc, ett_v120_header);
 181                 proto_tree_add_item(h_tree, hf_v120_header_ext16, tvb, 0, 2, ENC_BIG_ENDIAN);
 182                 proto_tree_add_item(h_tree, hf_v120_header_break16, tvb, 0, 2, ENC_BIG_ENDIAN);
 183                 proto_tree_add_item(h_tree, hf_v120_header_error_control16, tvb, 0, 2, ENC_BIG_ENDIAN);
 184                 proto_tree_add_item(h_tree, hf_v120_header_segb16, tvb, 0, 2, ENC_BIG_ENDIAN);
 185                 proto_tree_add_item(h_tree, hf_v120_header_segf16, tvb, 0, 2, ENC_BIG_ENDIAN);
 186                 proto_tree_add_item(h_tree, hf_v120_header_e, tvb, 0, 2, ENC_BIG_ENDIAN);
 187                 proto_tree_add_item(h_tree, hf_v120_header_dr, tvb, 0, 2, ENC_BIG_ENDIAN);
 188                 proto_tree_add_item(h_tree, hf_v120_header_sr, tvb, 0, 2, ENC_BIG_ENDIAN);
 189                 proto_tree_add_item(h_tree, hf_v120_header_rr, tvb, 0, 2, ENC_BIG_ENDIAN);
 190         }
 191
 192         proto_item_append_text(tc, " B: %d F: %d",
 193                                byte0 & 0x02 ? 1:0, byte0 & 0x01 ? 1:0);
 194
 195         return header_len;
 196 }
 197
 198 void
 199 proto_register_v120(void)
 200 {
 201         static hf_register_info hf[] = {
 202                 { &hf_v120_address,
 203                   { "Link Address", "v120.address", FT_UINT16, BASE_HEX, NULL,
 204                     0x0, NULL, HFILL }},
 205                 { &hf_v120_rc,
 206                   { "R/C", "v120.rc", FT_BOOLEAN, 16, TFS(&tfs_response_command),
 207                     0x0002, NULL, HFILL }},
 208                 { &hf_v120_lli,
 209                   { "LLI", "v120.lli", FT_UINT16, BASE_HEX, NULL,
 210                     0xfefc, NULL, HFILL }},
 211                 { &hf_v120_ea0,
 212                   { "EA0", "v120.ea0", FT_BOOLEAN, 16, TFS(&tfs_error_ok),
 213                     0x0001, NULL, HFILL }},
 214                 { &hf_v120_ea1,
 215                   { "EA1", "v120.ea1", FT_BOOLEAN, 16, TFS(&tfs_ok_error),
 216                     0x0100, NULL, HFILL }},
 217                 { &hf_v120_control,
 218                   { "Control Field", "v120.control", FT_UINT16, BASE_HEX, NULL, 0x0,
 219                     NULL, HFILL }},
 220                 { &hf_v120_n_r,
 221                   { "N(R)", "v120.control.n_r", FT_UINT16, BASE_DEC,
 222                     NULL, XDLC_N_R_EXT_MASK, NULL, HFILL }},
 223                 { &hf_v120_n_s,
 224                   { "N(S)", "v120.control.n_s", FT_UINT16, BASE_DEC,
 225                     NULL, XDLC_N_S_EXT_MASK, NULL, HFILL }},
 226                 { &hf_v120_p,
 227                   { "Poll", "v120.control.p", FT_BOOLEAN, 8,
 228                     TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }},
 229                 { &hf_v120_p_ext,
 230                   { "Poll", "v120.control.p", FT_BOOLEAN, 16,
 231                     TFS(&tfs_set_notset), XDLC_P_F_EXT, NULL, HFILL }},
 232                 { &hf_v120_f,
 233                   { "Final", "v120.control.f", FT_BOOLEAN, 8,
 234                     TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }},
 235                 { &hf_v120_f_ext,
 236                   { "Final", "v120.control.f", FT_BOOLEAN, 16,
 237                     TFS(&tfs_set_notset), XDLC_P_F_EXT, NULL, HFILL }},
 238                 { &hf_v120_s_ftype,
 239                   { "Supervisory frame type", "v120.control.s_ftype", FT_UINT16, BASE_HEX,
 240                     VALS(stype_vals), XDLC_S_FTYPE_MASK, NULL, HFILL }},
 241                 { &hf_v120_u_modifier_cmd,
 242                   { "Command", "v120.control.u_modifier_cmd", FT_UINT8, BASE_HEX,
 243                     VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, NULL, HFILL }},
 244                 { &hf_v120_u_modifier_resp,
 245                   { "Response", "v120.control.u_modifier_resp", FT_UINT8, BASE_HEX,
 246                     VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, NULL, HFILL }},
 247                 { &hf_v120_ftype_i,
 248                   { "Frame type", "v120.control.ftype", FT_UINT16, BASE_HEX,
 249                     VALS(ftype_vals), XDLC_I_MASK, NULL, HFILL }},
 250                 { &hf_v120_ftype_s_u,
 251                   { "Frame type", "v120.control.ftype", FT_UINT8, BASE_HEX,
 252                     VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }},
 253                 { &hf_v120_ftype_s_u_ext,
 254                   { "Frame type", "v120.control.ftype", FT_UINT16, BASE_HEX,
 255                     VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }},
 256                 { &hf_v120_header8,
 257                   { "Header", "v120.header", FT_UINT8, BASE_HEX, NULL, 0x0,
 258                     NULL, HFILL }},
 259                 { &hf_v120_header_ext8,
 260                   { "Extension octet", "v120.header.ext", FT_BOOLEAN, 8, TFS(&tfs_yes_no), 0x80,
 261                     NULL, HFILL }},
 262                 { &hf_v120_header_break8,
 263                   { "Break condition", "v120.header.break", FT_BOOLEAN, 8, TFS(&tfs_yes_no), 0x40,
 264                     NULL, HFILL }},
 265                 { &hf_v120_header_error_control8,
 266                   { "Error control C1/C2", "v120.error_control", FT_UINT8, BASE_HEX, NULL, 0x0C,
 267                     NULL, HFILL }},
 268                 { &hf_v120_header_segb8,
 269                   { "Bit B", "v120.header.segb", FT_BOOLEAN, 8, TFS(&tfs_segmentation_no_segmentation), 0x02,
 270                     NULL, HFILL }},
 271                 { &hf_v120_header_segf8,
 272                   { "Bit F", "v120.header.segf", FT_BOOLEAN, 8, TFS(&tfs_segmentation_no_segmentation), 0x01,
 273                     NULL, HFILL }},
 274                 { &hf_v120_header16,
 275                   { "Header", "v120.header", FT_UINT16, BASE_HEX, NULL, 0x0,
 276                     NULL, HFILL }},
 277                 { &hf_v120_header_ext16,
 278                   { "Extension octet", "v120.header.ext", FT_BOOLEAN, 16, TFS(&tfs_yes_no), 0x0080,
 279                     NULL, HFILL }},
 280                 { &hf_v120_header_break16,
 281                   { "Break condition", "v120.header.break", FT_BOOLEAN, 16, TFS(&tfs_yes_no), 0x0040,
 282                     NULL, HFILL }},
 283                 { &hf_v120_header_error_control16,
 284                   { "Error control C1/C2", "v120.error_control", FT_UINT16, BASE_HEX, NULL, 0x0C,
 285                     NULL, HFILL }},
 286                 { &hf_v120_header_segb16,
 287                   { "Bit B", "v120.header.segb", FT_BOOLEAN, 16, TFS(&tfs_segmentation_no_segmentation), 0x0002,
 288                     NULL, HFILL }},
 289                 { &hf_v120_header_segf16,
 290                   { "Bit F", "v120.header.segf", FT_BOOLEAN, 16, TFS(&tfs_segmentation_no_segmentation), 0x0001,
 291                     NULL, HFILL }},
 292                 { &hf_v120_header_e,
 293                   { "E", "v120.header.e", FT_BOOLEAN, 16, TFS(&tfs_yes_no), 0x8000,
 294                     NULL, HFILL }},
 295                 { &hf_v120_header_dr,
 296                   { "DR", "v120.header.dr", FT_BOOLEAN, 16, TFS(&tfs_yes_no), 0x4000,
 297                     NULL, HFILL }},
 298                 { &hf_v120_header_sr,
 299                   { "SR", "v120.header.sr", FT_BOOLEAN, 16, TFS(&tfs_yes_no), 0x2000,
 300                     NULL, HFILL }},
 301                 { &hf_v120_header_rr,
 302                   { "RR", "v120.header.rr", FT_BOOLEAN, 16, TFS(&tfs_yes_no), 0x1000,
 303                     NULL, HFILL }},
 304         };
 305         static int *ett[] = {
 306                 &ett_v120,
 307                 &ett_v120_address,
 308                 &ett_v120_control,
 309                 &ett_v120_header,
 310         };
 311
 312         proto_v120 = proto_register_protocol("Async data over ISDN (V.120)",
 313                                              "V.120", "v120");
 314         proto_register_field_array (proto_v120, hf, array_length(hf));
 315         proto_register_subtree_array(ett, array_length(ett));
 316
 317         register_dissector("v120", dissect_v120, proto_v120);
 318 }
 319
 320 /*
 321  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 322  *
 323  * Local variables:
 324  * c-basic-offset: 8
 325  * tab-width: 8
 326  * indent-tabs-mode: t
 327  * End:
 328  *
 329  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 330  * :indentSize=8:tabSize=8:noTabs=false:
 331  */