epan/dissectors/packet-tfp.c

   1 /* packet-tfp.c
   2  * Routines for Tinkerforge protocol packet disassembly
   3  * By Ishraq Ibne Ashraf <ishraq@tinkerforge.com>
   4  * Copyright 2013 Ishraq Ibne Ashraf
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * SPDX-License-Identifier: GPL-2.0-or-later
  11  */
  12
  13 #include "config.h"
  14
  15 #include <epan/packet.h>
  16 #include "packet-usb.h"
  17
  18 /* defines */
  19 #define tfp_PORT 4223 /* Not IANA registered */
  20
  21 #define tfp_USB_VENDOR_ID  0x16D0
  22 #define tfp_USB_PRODUCT_ID 0x063D
  23
  24 #define BASE58_MAX_STR_SIZE 13
  25
  26 void proto_reg_handoff_tfp(void);
  27 void proto_register_tfp(void);
  28
  29 static dissector_handle_t tfp_handle_tcp;
  30
  31 /* variables for creating the tree */
  32 static int proto_tfp;
  33 static int ett_tfp;
  34
  35 /* header field variables */
  36 static int hf_tfp_uid;
  37 static int hf_tfp_uid_numeric;
  38 static int hf_tfp_len;
  39 static int hf_tfp_fid;
  40 static int hf_tfp_seq;
  41 static int hf_tfp_r;
  42 static int hf_tfp_a;
  43 static int hf_tfp_oo;
  44 static int hf_tfp_e;
  45 static int hf_tfp_future_use;
  46 static int hf_tfp_payload;
  47
  48 /* bit and byte offsets for dissection */
  49 static const int byte_offset_len           = 4;
  50 static const int byte_offset_fid           = 5;
  51 static const int byte_count_tfp_uid        = 4;
  52 static const int byte_count_tfp_len        = 1;
  53 static const int byte_count_tfp_fid        = 1;
  54 static const int byte_count_tfp_flags      = 2;
  55 static const int bit_count_tfp_seq         = 4;
  56 static const int bit_count_tfp_r           = 1;
  57 static const int bit_count_tfp_a           = 1;
  58 static const int bit_count_tfp_oo          = 2;
  59 static const int bit_count_tfp_e           = 2;
  60 static const int bit_count_tfp_future_use = 6;
  61
  62 /* base58 encoding variable */
  63 static const char BASE58_ALPHABET[] =
  64         "123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";
  65
  66 /* function for encoding a number to base58 string */
  67 static void
  68 base58_encode(uint32_t value, char *str) {
  69
  70         uint32_t mod;
  71         int     i = 0;
  72         int     k;
  73         char    reverse_str[BASE58_MAX_STR_SIZE] = {'\0'};
  74
  75         while (value >= 58) {
  76                 mod = value % 58;
  77                 reverse_str[i] = BASE58_ALPHABET[mod];
  78                 value = value / 58;
  79                 ++i;
  80         }
  81
  82         reverse_str[i] = BASE58_ALPHABET[value];
  83
  84         for (k = 0; k <= i; k++) {
  85                 str[k] = reverse_str[i - k];
  86         }
  87
  88         for (; k < BASE58_MAX_STR_SIZE; k++) {
  89                 str[k] = '\0';
  90         }
  91 }
  92
  93 /* common dissector function for dissecting TFP payloads */
  94 static void
  95 dissect_tfp_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
  96
  97         int    byte_offset = 0;
  98         int    bit_offset  = 48;
  99
 100         uint8_t hv_tfp_len;
 101         uint8_t hv_tfp_fid;
 102         uint8_t hv_tfp_seq;
 103
 104         char   tfp_uid_string[BASE58_MAX_STR_SIZE];
 105
 106         base58_encode(tvb_get_letohl(tvb, 0), &tfp_uid_string[0]);
 107
 108         hv_tfp_len = tvb_get_uint8(tvb, byte_offset_len);
 109         hv_tfp_fid = tvb_get_uint8(tvb, byte_offset_fid);
 110         hv_tfp_seq = tvb_get_bits8(tvb, bit_offset, bit_count_tfp_seq);
 111
 112         col_add_fstr(pinfo->cinfo, COL_INFO,
 113                         "UID: %s, Len: %d, FID: %d, Seq: %d",
 114                         &tfp_uid_string[0], hv_tfp_len, hv_tfp_fid, hv_tfp_seq);
 115
 116         /* call for details */
 117         if (tree) {
 118                 proto_tree *tfp_tree;
 119                 proto_item *ti;
 120
 121                 ti = proto_tree_add_protocol_format(tree, proto_tfp, tvb, 0, -1,
 122                                                     "Tinkerforge Protocol, UID: %s, Len: %d, FID: %d, Seq: %d",
 123                                                     &tfp_uid_string[0], hv_tfp_len, hv_tfp_fid, hv_tfp_seq);
 124                 tfp_tree = proto_item_add_subtree(ti, ett_tfp);
 125
 126                 /* Use ...string_format_value() so we can show the complete generated string but specify */
 127                 /*  the field length as being just the 4 bytes from which the string is generated.       */
 128                 ti = proto_tree_add_string_format_value(tfp_tree,
 129                                                         hf_tfp_uid,
 130                                                         tvb, byte_offset, byte_count_tfp_uid,
 131                                                         &tfp_uid_string[0], "%s", &tfp_uid_string[0]);
 132                 proto_item_set_generated(ti);
 133
 134                 proto_tree_add_item(tfp_tree,
 135                                     hf_tfp_uid_numeric,
 136                                     tvb,
 137                                     byte_offset,
 138                                     byte_count_tfp_uid,
 139                                     ENC_LITTLE_ENDIAN);
 140
 141                 byte_offset += byte_count_tfp_uid;
 142
 143                 proto_tree_add_item(tfp_tree,
 144                                     hf_tfp_len,
 145                                     tvb,
 146                                     byte_offset,
 147                                     byte_count_tfp_len,
 148                                     ENC_LITTLE_ENDIAN);
 149
 150                 byte_offset += byte_count_tfp_len;
 151
 152                 proto_tree_add_item(tfp_tree,
 153                                     hf_tfp_fid,
 154                                     tvb,
 155                                     byte_offset,
 156                                     byte_count_tfp_fid,
 157                                     ENC_LITTLE_ENDIAN);
 158
 159                 byte_offset += byte_count_tfp_fid;
 160
 161                 proto_tree_add_bits_item(tfp_tree,
 162                                          hf_tfp_seq,
 163                                          tvb,
 164                                          bit_offset,
 165                                          bit_count_tfp_seq,
 166                                          ENC_LITTLE_ENDIAN);
 167
 168                 bit_offset += bit_count_tfp_seq;
 169
 170                 proto_tree_add_bits_item(tfp_tree,
 171                                          hf_tfp_r,
 172                                          tvb,
 173                                          bit_offset,
 174                                          bit_count_tfp_r,
 175                                          ENC_LITTLE_ENDIAN);
 176
 177                 bit_offset += bit_count_tfp_r;
 178
 179                 proto_tree_add_bits_item(tfp_tree,
 180                                          hf_tfp_a,
 181                                          tvb,
 182                                          bit_offset,
 183                                          bit_count_tfp_a,
 184                                          ENC_LITTLE_ENDIAN);
 185
 186                 bit_offset += bit_count_tfp_a;
 187
 188                 proto_tree_add_bits_item(tfp_tree,
 189                                          hf_tfp_oo,
 190                                          tvb,
 191                                          bit_offset,
 192                                          bit_count_tfp_oo,
 193                                          ENC_LITTLE_ENDIAN);
 194
 195                 bit_offset += bit_count_tfp_oo;
 196
 197                 proto_tree_add_bits_item(tfp_tree,
 198                                          hf_tfp_e,
 199                                          tvb,
 200                                          bit_offset,
 201                                          bit_count_tfp_e,
 202                                          ENC_LITTLE_ENDIAN);
 203
 204                 bit_offset += bit_count_tfp_e;
 205
 206                 proto_tree_add_bits_item(tfp_tree,
 207                                          hf_tfp_future_use,
 208                                          tvb,
 209                                          bit_offset,
 210                                          bit_count_tfp_future_use,
 211                                          ENC_LITTLE_ENDIAN);
 212
 213                 /*bit_offset += bit_count_tfp_future_use;*/
 214
 215                 if ((tvb_reported_length(tvb)) > 8) {
 216
 217                         byte_offset += byte_count_tfp_flags;
 218
 219                         proto_tree_add_item(tfp_tree, hf_tfp_payload, tvb, byte_offset, -1, ENC_NA);
 220                 }
 221         }
 222 }
 223
 224 /* dissector function for dissecting TCP payloads */
 225 static int
 226 dissect_tfp_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
 227 {
 228         col_set_str(pinfo->cinfo, COL_PROTOCOL, "TFP over TCP");
 229         col_clear(pinfo->cinfo, COL_INFO);
 230
 231         dissect_tfp_common(tvb, pinfo, tree);
 232         return tvb_captured_length(tvb);
 233 }
 234
 235 /* dissector function for dissecting USB payloads */
 236 static bool
 237 dissect_tfp_bulk_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
 238 {
 239         urb_info_t *urb = (urb_info_t *)data;
 240
 241         if ((urb != NULL) && (urb->conv != NULL) &&
 242                 (urb->conv->deviceVendor == tfp_USB_VENDOR_ID) &&
 243                 (urb->conv->deviceProduct == tfp_USB_PRODUCT_ID)) {
 244                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "TFP over USB");
 245                 col_clear(pinfo->cinfo, COL_INFO);
 246                 dissect_tfp_common(tvb, pinfo, tree);
 247                 return true;
 248         }
 249
 250         return false;
 251 }
 252
 253 /* protocol register function */
 254 void
 255 proto_register_tfp(void)
 256 {
 257         /* defining header formats */
 258         static hf_register_info hf_tfp[] = {
 259                 { &hf_tfp_uid,
 260                         { "UID (String)",
 261                           "tfp.uid",
 262                           FT_STRINGZ,
 263                           BASE_NONE,
 264                           NULL,
 265                           0x0,
 266                           NULL,
 267                           HFILL
 268                         }
 269                 },
 270                 { &hf_tfp_uid_numeric,
 271                         { "UID (Numeric)",
 272                           "tfp.uid_numeric",
 273                           FT_UINT32,
 274                           BASE_DEC,
 275                           NULL,
 276                           0x0,
 277                           NULL,
 278                           HFILL
 279                         }
 280                 },
 281                 { &hf_tfp_len,
 282                         { "Length",
 283                           "tfp.len",
 284                           FT_UINT8,
 285                           BASE_DEC,
 286                           NULL,
 287                           0x0,
 288                           NULL,
 289                           HFILL
 290                         }
 291                 },
 292                 { &hf_tfp_fid,
 293                         { "Function ID",
 294                           "tfp.fid",
 295                           FT_UINT8,
 296                           BASE_DEC,
 297                           NULL,
 298                           0x0,
 299                           NULL,
 300                           HFILL
 301                         }
 302                 },
 303                 { &hf_tfp_seq,
 304                         { "Sequence Number",
 305                           "tfp.seq",
 306                           FT_UINT8,
 307                           BASE_DEC,
 308                           NULL,
 309                           0x0,
 310                           NULL,
 311                           HFILL
 312                         }
 313                 },
 314                 { &hf_tfp_r,
 315                         { "Response Expected",
 316                           "tfp.r",
 317                           FT_UINT8,
 318                           BASE_DEC,
 319                           NULL,
 320                           0x0,
 321                           NULL,
 322                           HFILL
 323                         }
 324                 },
 325                 { &hf_tfp_a,
 326                         { "Authentication",
 327                           "tfp.a",
 328                           FT_UINT8,
 329                           BASE_DEC,
 330                           NULL,
 331                           0x0,
 332                           NULL,
 333                           HFILL
 334                         }
 335                 },
 336                 { &hf_tfp_oo,
 337                         { "Other Options",
 338                           "tfp.oo",
 339                           FT_UINT8,
 340                           BASE_DEC,
 341                           NULL,
 342                           0x0,
 343                           NULL,
 344                           HFILL
 345                         }
 346                 },
 347                 { &hf_tfp_e,
 348                         { "Error Code",
 349                           "tfp.e",
 350                           FT_UINT8,
 351                           BASE_DEC,
 352                           NULL,
 353                           0x0,
 354                           NULL,
 355                           HFILL
 356                         }
 357                 },
 358                 { &hf_tfp_future_use,
 359                         { "Future Use",
 360                           "tfp.future_use",
 361                           FT_UINT8,
 362                           BASE_DEC,
 363                           NULL,
 364                           0x0,
 365                           NULL,
 366                           HFILL
 367                         }
 368                 },
 369                 { &hf_tfp_payload,
 370                         { "Payload",
 371                           "tfp.payload",
 372                           FT_BYTES,
 373                           BASE_NONE,
 374                           NULL,
 375                           0x0,
 376                           NULL,
 377                           HFILL
 378                         }
 379                 }
 380         };
 381
 382         /* setup protocol subtree array */
 383         static int *ett[] = {
 384                 &ett_tfp
 385         };
 386
 387         /* defining the protocol and its names */
 388         proto_tfp = proto_register_protocol (
 389                 "Tinkerforge Protocol",
 390                 "TFP",
 391                 "tfp"
 392         );
 393
 394         proto_register_field_array(proto_tfp, hf_tfp, array_length(hf_tfp));
 395         proto_register_subtree_array(ett, array_length(ett));
 396         tfp_handle_tcp = register_dissector("tfp", dissect_tfp_tcp, proto_tfp);
 397 }
 398
 399 /* handoff function */
 400 void
 401 proto_reg_handoff_tfp(void) {
 402
 403         dissector_add_uint_with_preference("tcp.port", tfp_PORT, tfp_handle_tcp);
 404         heur_dissector_add("usb.bulk", dissect_tfp_bulk_heur, "Tinkerforge USB bulk endpoint", "tfp_usb_bulk", proto_tfp, HEURISTIC_ENABLE);
 405 }
 406
 407 /*
 408  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 409  *
 410  * Local variables:
 411  * c-basic-offset: 8
 412  * tab-width: 8
 413  * indent-tabs-mode: t
 414  * End:
 415  *
 416  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 417  * :indentSize=8:tabSize=8:noTabs=false:
 418  */