The Tcpdump Group git mirrors - tcpdump/blob - print-l2tp.c

   1 /*
   2  * Copyright (c) 1991, 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  *
  21  * L2TP support contributed by Motonori Shindo (mshindo@mshindo.net)
  22  */
  23
  24 /* \summary: Layer Two Tunneling Protocol (L2TP) printer */
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include <netdissect-stdinc.h>
  31
  32 #include "netdissect.h"
  33 #include "extract.h"
  34
  35 #define L2TP_FLAG_TYPE          0x8000  /* Type (0=Data, 1=Control) */
  36 #define L2TP_FLAG_LENGTH        0x4000  /* Length */
  37 #define L2TP_FLAG_SEQUENCE      0x0800  /* Sequence */
  38 #define L2TP_FLAG_OFFSET        0x0200  /* Offset */
  39 #define L2TP_FLAG_PRIORITY      0x0100  /* Priority */
  40
  41 #define L2TP_VERSION_MASK       0x000f  /* Version Mask */
  42 #define L2TP_VERSION_L2F        0x0001  /* L2F */
  43 #define L2TP_VERSION_L2TP       0x0002  /* L2TP */
  44
  45 #define L2TP_AVP_HDR_FLAG_MANDATORY     0x8000  /* Mandatory Flag */
  46 #define L2TP_AVP_HDR_FLAG_HIDDEN        0x4000  /* Hidden Flag */
  47 #define L2TP_AVP_HDR_LEN_MASK           0x03ff  /* Length Mask */
  48
  49 #define L2TP_FRAMING_CAP_SYNC_MASK      0x00000001      /* Synchronous */
  50 #define L2TP_FRAMING_CAP_ASYNC_MASK     0x00000002      /* Asynchronous */
  51
  52 #define L2TP_FRAMING_TYPE_SYNC_MASK     0x00000001      /* Synchronous */
  53 #define L2TP_FRAMING_TYPE_ASYNC_MASK    0x00000002      /* Asynchronous */
  54
  55 #define L2TP_BEARER_CAP_DIGITAL_MASK    0x00000001      /* Digital */
  56 #define L2TP_BEARER_CAP_ANALOG_MASK     0x00000002      /* Analog */
  57
  58 #define L2TP_BEARER_TYPE_DIGITAL_MASK   0x00000001      /* Digital */
  59 #define L2TP_BEARER_TYPE_ANALOG_MASK    0x00000002      /* Analog */
  60
  61 /* Authen Type */
  62 #define L2TP_AUTHEN_TYPE_RESERVED       0x0000  /* Reserved */
  63 #define L2TP_AUTHEN_TYPE_TEXTUAL        0x0001  /* Textual username/password exchange */
  64 #define L2TP_AUTHEN_TYPE_CHAP           0x0002  /* PPP CHAP */
  65 #define L2TP_AUTHEN_TYPE_PAP            0x0003  /* PPP PAP */
  66 #define L2TP_AUTHEN_TYPE_NO_AUTH        0x0004  /* No Authentication */
  67 #define L2TP_AUTHEN_TYPE_MSCHAPv1       0x0005  /* MSCHAPv1 */
  68
  69 #define L2TP_PROXY_AUTH_ID_MASK         0x00ff
  70
  71 static const char tstr[] = " [|l2tp]";
  72
  73 #define L2TP_MSGTYPE_SCCRQ      1  /* Start-Control-Connection-Request */
  74 #define L2TP_MSGTYPE_SCCRP      2  /* Start-Control-Connection-Reply */
  75 #define L2TP_MSGTYPE_SCCCN      3  /* Start-Control-Connection-Connected */
  76 #define L2TP_MSGTYPE_STOPCCN    4  /* Stop-Control-Connection-Notification */
  77 #define L2TP_MSGTYPE_HELLO      6  /* Hello */
  78 #define L2TP_MSGTYPE_OCRQ       7  /* Outgoing-Call-Request */
  79 #define L2TP_MSGTYPE_OCRP       8  /* Outgoing-Call-Reply */
  80 #define L2TP_MSGTYPE_OCCN       9  /* Outgoing-Call-Connected */
  81 #define L2TP_MSGTYPE_ICRQ       10 /* Incoming-Call-Request */
  82 #define L2TP_MSGTYPE_ICRP       11 /* Incoming-Call-Reply */
  83 #define L2TP_MSGTYPE_ICCN       12 /* Incoming-Call-Connected */
  84 #define L2TP_MSGTYPE_CDN        14 /* Call-Disconnect-Notify */
  85 #define L2TP_MSGTYPE_WEN        15 /* WAN-Error-Notify */
  86 #define L2TP_MSGTYPE_SLI        16 /* Set-Link-Info */
  87
  88 static const struct tok l2tp_msgtype2str[] = {
  89         { L2TP_MSGTYPE_SCCRQ,   "SCCRQ" },
  90         { L2TP_MSGTYPE_SCCRP,   "SCCRP" },
  91         { L2TP_MSGTYPE_SCCCN,   "SCCCN" },
  92         { L2TP_MSGTYPE_STOPCCN, "StopCCN" },
  93         { L2TP_MSGTYPE_HELLO,   "HELLO" },
  94         { L2TP_MSGTYPE_OCRQ,    "OCRQ" },
  95         { L2TP_MSGTYPE_OCRP,    "OCRP" },
  96         { L2TP_MSGTYPE_OCCN,    "OCCN" },
  97         { L2TP_MSGTYPE_ICRQ,    "ICRQ" },
  98         { L2TP_MSGTYPE_ICRP,    "ICRP" },
  99         { L2TP_MSGTYPE_ICCN,    "ICCN" },
 100         { L2TP_MSGTYPE_CDN,     "CDN" },
 101         { L2TP_MSGTYPE_WEN,     "WEN" },
 102         { L2TP_MSGTYPE_SLI,     "SLI" },
 103         { 0,                    NULL }
 104 };
 105
 106 #define L2TP_AVP_MSGTYPE                0  /* Message Type */
 107 #define L2TP_AVP_RESULT_CODE            1  /* Result Code */
 108 #define L2TP_AVP_PROTO_VER              2  /* Protocol Version */
 109 #define L2TP_AVP_FRAMING_CAP            3  /* Framing Capabilities */
 110 #define L2TP_AVP_BEARER_CAP             4  /* Bearer Capabilities */
 111 #define L2TP_AVP_TIE_BREAKER            5  /* Tie Breaker */
 112 #define L2TP_AVP_FIRM_VER               6  /* Firmware Revision */
 113 #define L2TP_AVP_HOST_NAME              7  /* Host Name */
 114 #define L2TP_AVP_VENDOR_NAME            8  /* Vendor Name */
 115 #define L2TP_AVP_ASSND_TUN_ID           9  /* Assigned Tunnel ID */
 116 #define L2TP_AVP_RECV_WIN_SIZE          10 /* Receive Window Size */
 117 #define L2TP_AVP_CHALLENGE              11 /* Challenge */
 118 #define L2TP_AVP_Q931_CC                12 /* Q.931 Cause Code */
 119 #define L2TP_AVP_CHALLENGE_RESP         13 /* Challenge Response */
 120 #define L2TP_AVP_ASSND_SESS_ID          14 /* Assigned Session ID */
 121 #define L2TP_AVP_CALL_SER_NUM           15 /* Call Serial Number */
 122 #define L2TP_AVP_MINIMUM_BPS            16 /* Minimum BPS */
 123 #define L2TP_AVP_MAXIMUM_BPS            17 /* Maximum BPS */
 124 #define L2TP_AVP_BEARER_TYPE            18 /* Bearer Type */
 125 #define L2TP_AVP_FRAMING_TYPE           19 /* Framing Type */
 126 #define L2TP_AVP_PACKET_PROC_DELAY      20 /* Packet Processing Delay (OBSOLETE) */
 127 #define L2TP_AVP_CALLED_NUMBER          21 /* Called Number */
 128 #define L2TP_AVP_CALLING_NUMBER         22 /* Calling Number */
 129 #define L2TP_AVP_SUB_ADDRESS            23 /* Sub-Address */
 130 #define L2TP_AVP_TX_CONN_SPEED          24 /* (Tx) Connect Speed */
 131 #define L2TP_AVP_PHY_CHANNEL_ID         25 /* Physical Channel ID */
 132 #define L2TP_AVP_INI_RECV_LCP           26 /* Initial Received LCP CONFREQ */
 133 #define L2TP_AVP_LAST_SENT_LCP          27 /* Last Sent LCP CONFREQ */
 134 #define L2TP_AVP_LAST_RECV_LCP          28 /* Last Received LCP CONFREQ */
 135 #define L2TP_AVP_PROXY_AUTH_TYPE        29 /* Proxy Authen Type */
 136 #define L2TP_AVP_PROXY_AUTH_NAME        30 /* Proxy Authen Name */
 137 #define L2TP_AVP_PROXY_AUTH_CHAL        31 /* Proxy Authen Challenge */
 138 #define L2TP_AVP_PROXY_AUTH_ID          32 /* Proxy Authen ID */
 139 #define L2TP_AVP_PROXY_AUTH_RESP        33 /* Proxy Authen Response */
 140 #define L2TP_AVP_CALL_ERRORS            34 /* Call Errors */
 141 #define L2TP_AVP_ACCM                   35 /* ACCM */
 142 #define L2TP_AVP_RANDOM_VECTOR          36 /* Random Vector */
 143 #define L2TP_AVP_PRIVATE_GRP_ID         37 /* Private Group ID */
 144 #define L2TP_AVP_RX_CONN_SPEED          38 /* (Rx) Connect Speed */
 145 #define L2TP_AVP_SEQ_REQUIRED           39 /* Sequencing Required */
 146 #define L2TP_AVP_PPP_DISCON_CC          46 /* PPP Disconnect Cause Code */
 147
 148 static const struct tok l2tp_avp2str[] = {
 149         { L2TP_AVP_MSGTYPE,             "MSGTYPE" },
 150         { L2TP_AVP_RESULT_CODE,         "RESULT_CODE" },
 151         { L2TP_AVP_PROTO_VER,           "PROTO_VER" },
 152         { L2TP_AVP_FRAMING_CAP,         "FRAMING_CAP" },
 153         { L2TP_AVP_BEARER_CAP,          "BEARER_CAP" },
 154         { L2TP_AVP_TIE_BREAKER,         "TIE_BREAKER" },
 155         { L2TP_AVP_FIRM_VER,            "FIRM_VER" },
 156         { L2TP_AVP_HOST_NAME,           "HOST_NAME" },
 157         { L2TP_AVP_VENDOR_NAME,         "VENDOR_NAME" },
 158         { L2TP_AVP_ASSND_TUN_ID,        "ASSND_TUN_ID" },
 159         { L2TP_AVP_RECV_WIN_SIZE,       "RECV_WIN_SIZE" },
 160         { L2TP_AVP_CHALLENGE,           "CHALLENGE" },
 161         { L2TP_AVP_Q931_CC,             "Q931_CC", },
 162         { L2TP_AVP_CHALLENGE_RESP,      "CHALLENGE_RESP" },
 163         { L2TP_AVP_ASSND_SESS_ID,       "ASSND_SESS_ID" },
 164         { L2TP_AVP_CALL_SER_NUM,        "CALL_SER_NUM" },
 165         { L2TP_AVP_MINIMUM_BPS,         "MINIMUM_BPS" },
 166         { L2TP_AVP_MAXIMUM_BPS,         "MAXIMUM_BPS" },
 167         { L2TP_AVP_BEARER_TYPE,         "BEARER_TYPE" },
 168         { L2TP_AVP_FRAMING_TYPE,        "FRAMING_TYPE" },
 169         { L2TP_AVP_PACKET_PROC_DELAY,   "PACKET_PROC_DELAY" },
 170         { L2TP_AVP_CALLED_NUMBER,       "CALLED_NUMBER" },
 171         { L2TP_AVP_CALLING_NUMBER,      "CALLING_NUMBER" },
 172         { L2TP_AVP_SUB_ADDRESS,         "SUB_ADDRESS" },
 173         { L2TP_AVP_TX_CONN_SPEED,       "TX_CONN_SPEED" },
 174         { L2TP_AVP_PHY_CHANNEL_ID,      "PHY_CHANNEL_ID" },
 175         { L2TP_AVP_INI_RECV_LCP,        "INI_RECV_LCP" },
 176         { L2TP_AVP_LAST_SENT_LCP,       "LAST_SENT_LCP" },
 177         { L2TP_AVP_LAST_RECV_LCP,       "LAST_RECV_LCP" },
 178         { L2TP_AVP_PROXY_AUTH_TYPE,     "PROXY_AUTH_TYPE" },
 179         { L2TP_AVP_PROXY_AUTH_NAME,     "PROXY_AUTH_NAME" },
 180         { L2TP_AVP_PROXY_AUTH_CHAL,     "PROXY_AUTH_CHAL" },
 181         { L2TP_AVP_PROXY_AUTH_ID,       "PROXY_AUTH_ID" },
 182         { L2TP_AVP_PROXY_AUTH_RESP,     "PROXY_AUTH_RESP" },
 183         { L2TP_AVP_CALL_ERRORS,         "CALL_ERRORS" },
 184         { L2TP_AVP_ACCM,                "ACCM" },
 185         { L2TP_AVP_RANDOM_VECTOR,       "RANDOM_VECTOR" },
 186         { L2TP_AVP_PRIVATE_GRP_ID,      "PRIVATE_GRP_ID" },
 187         { L2TP_AVP_RX_CONN_SPEED,       "RX_CONN_SPEED" },
 188         { L2TP_AVP_SEQ_REQUIRED,        "SEQ_REQUIRED" },
 189         { L2TP_AVP_PPP_DISCON_CC,       "PPP_DISCON_CC" },
 190         { 0,                            NULL }
 191 };
 192
 193 static const struct tok l2tp_authentype2str[] = {
 194         { L2TP_AUTHEN_TYPE_RESERVED,    "Reserved" },
 195         { L2TP_AUTHEN_TYPE_TEXTUAL,     "Textual" },
 196         { L2TP_AUTHEN_TYPE_CHAP,        "CHAP" },
 197         { L2TP_AUTHEN_TYPE_PAP,         "PAP" },
 198         { L2TP_AUTHEN_TYPE_NO_AUTH,     "No Auth" },
 199         { L2TP_AUTHEN_TYPE_MSCHAPv1,    "MS-CHAPv1" },
 200         { 0,                            NULL }
 201 };
 202
 203 #define L2TP_PPP_DISCON_CC_DIRECTION_GLOBAL     0
 204 #define L2TP_PPP_DISCON_CC_DIRECTION_AT_PEER    1
 205 #define L2TP_PPP_DISCON_CC_DIRECTION_AT_LOCAL   2
 206
 207 static const struct tok l2tp_cc_direction2str[] = {
 208         { L2TP_PPP_DISCON_CC_DIRECTION_GLOBAL,  "global error" },
 209         { L2TP_PPP_DISCON_CC_DIRECTION_AT_PEER, "at peer" },
 210         { L2TP_PPP_DISCON_CC_DIRECTION_AT_LOCAL,"at local" },
 211         { 0,                                    NULL }
 212 };
 213
 214 #if 0
 215 static char *l2tp_result_code_StopCCN[] = {
 216          "Reserved",
 217          "General request to clear control connection",
 218          "General error--Error Code indicates the problem",
 219          "Control channel already exists",
 220          "Requester is not authorized to establish a control channel",
 221          "The protocol version of the requester is not supported",
 222          "Requester is being shut down",
 223          "Finite State Machine error"
 224 #define L2TP_MAX_RESULT_CODE_STOPCC_INDEX       8
 225 };
 226 #endif
 227
 228 #if 0
 229 static char *l2tp_result_code_CDN[] = {
 230         "Reserved",
 231         "Call disconnected due to loss of carrier",
 232         "Call disconnected for the reason indicated in error code",
 233         "Call disconnected for administrative reasons",
 234         "Call failed due to lack of appropriate facilities being " \
 235         "available (temporary condition)",
 236         "Call failed due to lack of appropriate facilities being " \
 237         "available (permanent condition)",
 238         "Invalid destination",
 239         "Call failed due to no carrier detected",
 240         "Call failed due to detection of a busy signal",
 241         "Call failed due to lack of a dial tone",
 242         "Call was not established within time allotted by LAC",
 243         "Call was connected but no appropriate framing was detected"
 244 #define L2TP_MAX_RESULT_CODE_CDN_INDEX  12
 245 };
 246 #endif
 247
 248 #if 0
 249 static char *l2tp_error_code_general[] = {
 250         "No general error",
 251         "No control connection exists yet for this LAC-LNS pair",
 252         "Length is wrong",
 253         "One of the field values was out of range or " \
 254         "reserved field was non-zero"
 255         "Insufficient resources to handle this operation now",
 256         "The Session ID is invalid in this context",
 257         "A generic vendor-specific error occurred in the LAC",
 258         "Try another"
 259 #define L2TP_MAX_ERROR_CODE_GENERAL_INDEX       8
 260 };
 261 #endif
 262
 263 /******************************/
 264 /* generic print out routines */
 265 /******************************/
 266 static void
 267 print_string(netdissect_options *ndo, const u_char *dat, u_int length)
 268 {
 269         u_int i;
 270         for (i=0; i<length; i++) {
 271                 ND_PRINT((ndo, "%c", EXTRACT_U_1(dat)));
 272                 dat++;
 273         }
 274 }
 275
 276 static void
 277 print_octets(netdissect_options *ndo, const u_char *dat, u_int length)
 278 {
 279         u_int i;
 280         for (i=0; i<length; i++) {
 281                 ND_PRINT((ndo, "%02x", EXTRACT_U_1(dat)));
 282                 dat++;
 283         }
 284 }
 285
 286 static void
 287 print_16bits_val(netdissect_options *ndo, const uint16_t *dat)
 288 {
 289         ND_PRINT((ndo, "%u", EXTRACT_BE_U_2(dat)));
 290 }
 291
 292 static void
 293 print_32bits_val(netdissect_options *ndo, const uint32_t *dat)
 294 {
 295         ND_PRINT((ndo, "%lu", (u_long) EXTRACT_BE_U_4(dat)));
 296 }
 297
 298 /***********************************/
 299 /* AVP-specific print out routines */
 300 /***********************************/
 301 static void
 302 l2tp_msgtype_print(netdissect_options *ndo, const u_char *dat, u_int length)
 303 {
 304         const uint16_t *ptr = (const uint16_t *)dat;
 305
 306         if (length < 2) {
 307                 ND_PRINT((ndo, "AVP too short"));
 308                 return;
 309         }
 310         ND_PRINT((ndo, "%s", tok2str(l2tp_msgtype2str, "MSGTYPE-#%u",
 311             EXTRACT_BE_U_2(ptr))));
 312 }
 313
 314 static void
 315 l2tp_result_code_print(netdissect_options *ndo, const u_char *dat, u_int length)
 316 {
 317         const uint16_t *ptr = (const uint16_t *)dat;
 318
 319         /* Result Code */
 320         if (length < 2) {
 321                 ND_PRINT((ndo, "AVP too short"));
 322                 return;
 323         }
 324         ND_PRINT((ndo, "%u", EXTRACT_BE_U_2(ptr)));
 325         ptr++;
 326         length -= 2;
 327
 328         /* Error Code (opt) */
 329         if (length == 0)
 330                 return;
 331         if (length < 2) {
 332                 ND_PRINT((ndo, " AVP too short"));
 333                 return;
 334         }
 335         ND_PRINT((ndo, "/%u", EXTRACT_BE_U_2(ptr)));
 336         ptr++;
 337         length -= 2;
 338
 339         /* Error Message (opt) */
 340         if (length == 0)
 341                 return;
 342         ND_PRINT((ndo, " "));
 343         print_string(ndo, (const u_char *)ptr, length);
 344 }
 345
 346 static void
 347 l2tp_proto_ver_print(netdissect_options *ndo, const uint16_t *dat, u_int length)
 348 {
 349         if (length < 2) {
 350                 ND_PRINT((ndo, "AVP too short"));
 351                 return;
 352         }
 353         ND_PRINT((ndo, "%u.%u", (EXTRACT_BE_U_2(dat) >> 8),
 354                   (EXTRACT_BE_U_2(dat) & 0xff)));
 355 }
 356
 357 static void
 358 l2tp_framing_cap_print(netdissect_options *ndo, const u_char *dat, u_int length)
 359 {
 360         const uint32_t *ptr = (const uint32_t *)dat;
 361
 362         if (length < 4) {
 363                 ND_PRINT((ndo, "AVP too short"));
 364                 return;
 365         }
 366         if (EXTRACT_BE_U_4(ptr) &  L2TP_FRAMING_CAP_ASYNC_MASK) {
 367                 ND_PRINT((ndo, "A"));
 368         }
 369         if (EXTRACT_BE_U_4(ptr) &  L2TP_FRAMING_CAP_SYNC_MASK) {
 370                 ND_PRINT((ndo, "S"));
 371         }
 372 }
 373
 374 static void
 375 l2tp_bearer_cap_print(netdissect_options *ndo, const u_char *dat, u_int length)
 376 {
 377         const uint32_t *ptr = (const uint32_t *)dat;
 378
 379         if (length < 4) {
 380                 ND_PRINT((ndo, "AVP too short"));
 381                 return;
 382         }
 383         if (EXTRACT_BE_U_4(ptr) &  L2TP_BEARER_CAP_ANALOG_MASK) {
 384                 ND_PRINT((ndo, "A"));
 385         }
 386         if (EXTRACT_BE_U_4(ptr) &  L2TP_BEARER_CAP_DIGITAL_MASK) {
 387                 ND_PRINT((ndo, "D"));
 388         }
 389 }
 390
 391 static void
 392 l2tp_q931_cc_print(netdissect_options *ndo, const u_char *dat, u_int length)
 393 {
 394         if (length < 3) {
 395                 ND_PRINT((ndo, "AVP too short"));
 396                 return;
 397         }
 398         print_16bits_val(ndo, (const uint16_t *)dat);
 399         ND_PRINT((ndo, ", %02x", EXTRACT_U_1(dat + 2)));
 400         dat += 3;
 401         length -= 3;
 402         if (length != 0) {
 403                 ND_PRINT((ndo, " "));
 404                 print_string(ndo, dat, length);
 405         }
 406 }
 407
 408 static void
 409 l2tp_bearer_type_print(netdissect_options *ndo, const u_char *dat, u_int length)
 410 {
 411         const uint32_t *ptr = (const uint32_t *)dat;
 412
 413         if (length < 4) {
 414                 ND_PRINT((ndo, "AVP too short"));
 415                 return;
 416         }
 417         if (EXTRACT_BE_U_4(ptr) &  L2TP_BEARER_TYPE_ANALOG_MASK) {
 418                 ND_PRINT((ndo, "A"));
 419         }
 420         if (EXTRACT_BE_U_4(ptr) &  L2TP_BEARER_TYPE_DIGITAL_MASK) {
 421                 ND_PRINT((ndo, "D"));
 422         }
 423 }
 424
 425 static void
 426 l2tp_framing_type_print(netdissect_options *ndo, const u_char *dat, u_int length)
 427 {
 428         const uint32_t *ptr = (const uint32_t *)dat;
 429
 430         if (length < 4) {
 431                 ND_PRINT((ndo, "AVP too short"));
 432                 return;
 433         }
 434         if (EXTRACT_BE_U_4(ptr) &  L2TP_FRAMING_TYPE_ASYNC_MASK) {
 435                 ND_PRINT((ndo, "A"));
 436         }
 437         if (EXTRACT_BE_U_4(ptr) &  L2TP_FRAMING_TYPE_SYNC_MASK) {
 438                 ND_PRINT((ndo, "S"));
 439         }
 440 }
 441
 442 static void
 443 l2tp_packet_proc_delay_print(netdissect_options *ndo)
 444 {
 445         ND_PRINT((ndo, "obsolete"));
 446 }
 447
 448 static void
 449 l2tp_proxy_auth_type_print(netdissect_options *ndo, const u_char *dat, u_int length)
 450 {
 451         const uint16_t *ptr = (const uint16_t *)dat;
 452
 453         if (length < 2) {
 454                 ND_PRINT((ndo, "AVP too short"));
 455                 return;
 456         }
 457         ND_PRINT((ndo, "%s", tok2str(l2tp_authentype2str,
 458                              "AuthType-#%u", EXTRACT_BE_U_2(ptr))));
 459 }
 460
 461 static void
 462 l2tp_proxy_auth_id_print(netdissect_options *ndo, const u_char *dat, u_int length)
 463 {
 464         const uint16_t *ptr = (const uint16_t *)dat;
 465
 466         if (length < 2) {
 467                 ND_PRINT((ndo, "AVP too short"));
 468                 return;
 469         }
 470         ND_PRINT((ndo, "%u", EXTRACT_BE_U_2(ptr) & L2TP_PROXY_AUTH_ID_MASK));
 471 }
 472
 473 static void
 474 l2tp_call_errors_print(netdissect_options *ndo, const u_char *dat, u_int length)
 475 {
 476         const uint16_t *ptr = (const uint16_t *)dat;
 477         uint16_t val_h, val_l;
 478
 479         if (length < 2) {
 480                 ND_PRINT((ndo, "AVP too short"));
 481                 return;
 482         }
 483         ptr++;          /* skip "Reserved" */
 484         length -= 2;
 485
 486         if (length < 4) {
 487                 ND_PRINT((ndo, "AVP too short"));
 488                 return;
 489         }
 490         val_h = EXTRACT_BE_U_2(ptr); ptr++; length -= 2;
 491         val_l = EXTRACT_BE_U_2(ptr); ptr++; length -= 2;
 492         ND_PRINT((ndo, "CRCErr=%u ", (val_h<<16) + val_l));
 493
 494         if (length < 4) {
 495                 ND_PRINT((ndo, "AVP too short"));
 496                 return;
 497         }
 498         val_h = EXTRACT_BE_U_2(ptr); ptr++; length -= 2;
 499         val_l = EXTRACT_BE_U_2(ptr); ptr++; length -= 2;
 500         ND_PRINT((ndo, "FrameErr=%u ", (val_h<<16) + val_l));
 501
 502         if (length < 4) {
 503                 ND_PRINT((ndo, "AVP too short"));
 504                 return;
 505         }
 506         val_h = EXTRACT_BE_U_2(ptr); ptr++; length -= 2;
 507         val_l = EXTRACT_BE_U_2(ptr); ptr++; length -= 2;
 508         ND_PRINT((ndo, "HardOver=%u ", (val_h<<16) + val_l));
 509
 510         if (length < 4) {
 511                 ND_PRINT((ndo, "AVP too short"));
 512                 return;
 513         }
 514         val_h = EXTRACT_BE_U_2(ptr); ptr++; length -= 2;
 515         val_l = EXTRACT_BE_U_2(ptr); ptr++; length -= 2;
 516         ND_PRINT((ndo, "BufOver=%u ", (val_h<<16) + val_l));
 517
 518         if (length < 4) {
 519                 ND_PRINT((ndo, "AVP too short"));
 520                 return;
 521         }
 522         val_h = EXTRACT_BE_U_2(ptr); ptr++; length -= 2;
 523         val_l = EXTRACT_BE_U_2(ptr); ptr++; length -= 2;
 524         ND_PRINT((ndo, "Timeout=%u ", (val_h<<16) + val_l));
 525
 526         if (length < 4) {
 527                 ND_PRINT((ndo, "AVP too short"));
 528                 return;
 529         }
 530         val_h = EXTRACT_BE_U_2(ptr); ptr++;
 531         val_l = EXTRACT_BE_U_2(ptr); ptr++;
 532         ND_PRINT((ndo, "AlignErr=%u ", (val_h<<16) + val_l));
 533 }
 534
 535 static void
 536 l2tp_accm_print(netdissect_options *ndo, const u_char *dat, u_int length)
 537 {
 538         const uint16_t *ptr = (const uint16_t *)dat;
 539         uint16_t val_h, val_l;
 540
 541         if (length < 2) {
 542                 ND_PRINT((ndo, "AVP too short"));
 543                 return;
 544         }
 545         ptr++;          /* skip "Reserved" */
 546         length -= 2;
 547
 548         if (length < 4) {
 549                 ND_PRINT((ndo, "AVP too short"));
 550                 return;
 551         }
 552         val_h = EXTRACT_BE_U_2(ptr); ptr++; length -= 2;
 553         val_l = EXTRACT_BE_U_2(ptr); ptr++; length -= 2;
 554         ND_PRINT((ndo, "send=%08x ", (val_h<<16) + val_l));
 555
 556         if (length < 4) {
 557                 ND_PRINT((ndo, "AVP too short"));
 558                 return;
 559         }
 560         val_h = EXTRACT_BE_U_2(ptr); ptr++;
 561         val_l = EXTRACT_BE_U_2(ptr); ptr++;
 562         ND_PRINT((ndo, "recv=%08x ", (val_h<<16) + val_l));
 563 }
 564
 565 static void
 566 l2tp_ppp_discon_cc_print(netdissect_options *ndo, const u_char *dat, u_int length)
 567 {
 568         const uint16_t *ptr = (const uint16_t *)dat;
 569
 570         if (length < 5) {
 571                 ND_PRINT((ndo, "AVP too short"));
 572                 return;
 573         }
 574         /* Disconnect Code */
 575         ND_PRINT((ndo, "%04x, ", EXTRACT_BE_U_2(dat)));
 576         dat += 2;
 577         length -= 2;
 578         /* Control Protocol Number */
 579         ND_PRINT((ndo, "%04x ",  EXTRACT_BE_U_2(dat)));
 580         dat += 2;
 581         length -= 2;
 582         /* Direction */
 583         ND_PRINT((ndo, "%s", tok2str(l2tp_cc_direction2str,
 584                              "Direction-#%u", EXTRACT_U_1(ptr))));
 585         ptr++;
 586         length--;
 587
 588         if (length != 0) {
 589                 ND_PRINT((ndo, " "));
 590                 print_string(ndo, (const u_char *)ptr, length);
 591         }
 592 }
 593
 594 static void
 595 l2tp_avp_print(netdissect_options *ndo, const u_char *dat, int length)
 596 {
 597         u_int len;
 598         const uint16_t *ptr = (const uint16_t *)dat;
 599         uint16_t attr_type;
 600         int hidden = FALSE;
 601
 602         if (length <= 0) {
 603                 return;
 604         }
 605
 606         ND_PRINT((ndo, " "));
 607
 608         ND_TCHECK(*ptr);        /* Flags & Length */
 609         len = EXTRACT_BE_U_2(ptr) & L2TP_AVP_HDR_LEN_MASK;
 610
 611         /* If it is not long enough to contain the header, we'll give up. */
 612         if (len < 6)
 613                 goto trunc;
 614
 615         /* If it goes past the end of the remaining length of the packet,
 616            we'll give up. */
 617         if (len > (u_int)length)
 618                 goto trunc;
 619
 620         /* If it goes past the end of the remaining length of the captured
 621            data, we'll give up. */
 622         ND_TCHECK2(*ptr, len);
 623
 624         /*
 625          * After this point, we don't need to check whether we go past
 626          * the length of the captured data; however, we *do* need to
 627          * check whether we go past the end of the AVP.
 628          */
 629
 630         if (EXTRACT_BE_U_2(ptr) & L2TP_AVP_HDR_FLAG_MANDATORY) {
 631                 ND_PRINT((ndo, "*"));
 632         }
 633         if (EXTRACT_BE_U_2(ptr) & L2TP_AVP_HDR_FLAG_HIDDEN) {
 634                 hidden = TRUE;
 635                 ND_PRINT((ndo, "?"));
 636         }
 637         ptr++;
 638
 639         if (EXTRACT_BE_U_2(ptr)) {
 640                 /* Vendor Specific Attribute */
 641                 ND_PRINT((ndo, "VENDOR%04x:", EXTRACT_BE_U_2(ptr))); ptr++;
 642                 ND_PRINT((ndo, "ATTR%04x", EXTRACT_BE_U_2(ptr))); ptr++;
 643                 ND_PRINT((ndo, "("));
 644                 print_octets(ndo, (const u_char *)ptr, len-6);
 645                 ND_PRINT((ndo, ")"));
 646         } else {
 647                 /* IETF-defined Attributes */
 648                 ptr++;
 649                 attr_type = EXTRACT_BE_U_2(ptr); ptr++;
 650                 ND_PRINT((ndo, "%s", tok2str(l2tp_avp2str, "AVP-#%u", attr_type)));
 651                 ND_PRINT((ndo, "("));
 652                 if (hidden) {
 653                         ND_PRINT((ndo, "???"));
 654                 } else {
 655                         switch (attr_type) {
 656                         case L2TP_AVP_MSGTYPE:
 657                                 l2tp_msgtype_print(ndo, (const u_char *)ptr, len-6);
 658                                 break;
 659                         case L2TP_AVP_RESULT_CODE:
 660                                 l2tp_result_code_print(ndo, (const u_char *)ptr, len-6);
 661                                 break;
 662                         case L2TP_AVP_PROTO_VER:
 663                                 l2tp_proto_ver_print(ndo, ptr, len-6);
 664                                 break;
 665                         case L2TP_AVP_FRAMING_CAP:
 666                                 l2tp_framing_cap_print(ndo, (const u_char *)ptr, len-6);
 667                                 break;
 668                         case L2TP_AVP_BEARER_CAP:
 669                                 l2tp_bearer_cap_print(ndo, (const u_char *)ptr, len-6);
 670                                 break;
 671                         case L2TP_AVP_TIE_BREAKER:
 672                                 if (len-6 < 8) {
 673                                         ND_PRINT((ndo, "AVP too short"));
 674                                         break;
 675                                 }
 676                                 print_octets(ndo, (const u_char *)ptr, 8);
 677                                 break;
 678                         case L2TP_AVP_FIRM_VER:
 679                         case L2TP_AVP_ASSND_TUN_ID:
 680                         case L2TP_AVP_RECV_WIN_SIZE:
 681                         case L2TP_AVP_ASSND_SESS_ID:
 682                                 if (len-6 < 2) {
 683                                         ND_PRINT((ndo, "AVP too short"));
 684                                         break;
 685                                 }
 686                                 print_16bits_val(ndo, ptr);
 687                                 break;
 688                         case L2TP_AVP_HOST_NAME:
 689                         case L2TP_AVP_VENDOR_NAME:
 690                         case L2TP_AVP_CALLING_NUMBER:
 691                         case L2TP_AVP_CALLED_NUMBER:
 692                         case L2TP_AVP_SUB_ADDRESS:
 693                         case L2TP_AVP_PROXY_AUTH_NAME:
 694                         case L2TP_AVP_PRIVATE_GRP_ID:
 695                                 print_string(ndo, (const u_char *)ptr, len-6);
 696                                 break;
 697                         case L2TP_AVP_CHALLENGE:
 698                         case L2TP_AVP_INI_RECV_LCP:
 699                         case L2TP_AVP_LAST_SENT_LCP:
 700                         case L2TP_AVP_LAST_RECV_LCP:
 701                         case L2TP_AVP_PROXY_AUTH_CHAL:
 702                         case L2TP_AVP_PROXY_AUTH_RESP:
 703                         case L2TP_AVP_RANDOM_VECTOR:
 704                                 print_octets(ndo, (const u_char *)ptr, len-6);
 705                                 break;
 706                         case L2TP_AVP_Q931_CC:
 707                                 l2tp_q931_cc_print(ndo, (const u_char *)ptr, len-6);
 708                                 break;
 709                         case L2TP_AVP_CHALLENGE_RESP:
 710                                 if (len-6 < 16) {
 711                                         ND_PRINT((ndo, "AVP too short"));
 712                                         break;
 713                                 }
 714                                 print_octets(ndo, (const u_char *)ptr, 16);
 715                                 break;
 716                         case L2TP_AVP_CALL_SER_NUM:
 717                         case L2TP_AVP_MINIMUM_BPS:
 718                         case L2TP_AVP_MAXIMUM_BPS:
 719                         case L2TP_AVP_TX_CONN_SPEED:
 720                         case L2TP_AVP_PHY_CHANNEL_ID:
 721                         case L2TP_AVP_RX_CONN_SPEED:
 722                                 if (len-6 < 4) {
 723                                         ND_PRINT((ndo, "AVP too short"));
 724                                         break;
 725                                 }
 726                                 print_32bits_val(ndo, (const uint32_t *)ptr);
 727                                 break;
 728                         case L2TP_AVP_BEARER_TYPE:
 729                                 l2tp_bearer_type_print(ndo, (const u_char *)ptr, len-6);
 730                                 break;
 731                         case L2TP_AVP_FRAMING_TYPE:
 732                                 l2tp_framing_type_print(ndo, (const u_char *)ptr, len-6);
 733                                 break;
 734                         case L2TP_AVP_PACKET_PROC_DELAY:
 735                                 l2tp_packet_proc_delay_print(ndo);
 736                                 break;
 737                         case L2TP_AVP_PROXY_AUTH_TYPE:
 738                                 l2tp_proxy_auth_type_print(ndo, (const u_char *)ptr, len-6);
 739                                 break;
 740                         case L2TP_AVP_PROXY_AUTH_ID:
 741                                 l2tp_proxy_auth_id_print(ndo, (const u_char *)ptr, len-6);
 742                                 break;
 743                         case L2TP_AVP_CALL_ERRORS:
 744                                 l2tp_call_errors_print(ndo, (const u_char *)ptr, len-6);
 745                                 break;
 746                         case L2TP_AVP_ACCM:
 747                                 l2tp_accm_print(ndo, (const u_char *)ptr, len-6);
 748                                 break;
 749                         case L2TP_AVP_SEQ_REQUIRED:
 750                                 break;  /* No Attribute Value */
 751                         case L2TP_AVP_PPP_DISCON_CC:
 752                                 l2tp_ppp_discon_cc_print(ndo, (const u_char *)ptr, len-6);
 753                                 break;
 754                         default:
 755                                 break;
 756                         }
 757                 }
 758                 ND_PRINT((ndo, ")"));
 759         }
 760
 761         l2tp_avp_print(ndo, dat+len, length-len);
 762         return;
 763
 764  trunc:
 765         ND_PRINT((ndo, "|..."));
 766 }
 767
 768
 769 void
 770 l2tp_print(netdissect_options *ndo, const u_char *dat, u_int length)
 771 {
 772         const u_char *ptr = dat;
 773         u_int cnt = 0;                  /* total octets consumed */
 774         uint16_t pad;
 775         int flag_t, flag_l, flag_s, flag_o;
 776         uint16_t l2tp_len;
 777
 778         flag_t = flag_l = flag_s = flag_o = FALSE;
 779
 780         ND_TCHECK_2(ptr);       /* Flags & Version */
 781         if ((EXTRACT_BE_U_2(ptr) & L2TP_VERSION_MASK) == L2TP_VERSION_L2TP) {
 782                 ND_PRINT((ndo, " l2tp:"));
 783         } else if ((EXTRACT_BE_U_2(ptr) & L2TP_VERSION_MASK) == L2TP_VERSION_L2F) {
 784                 ND_PRINT((ndo, " l2f:"));
 785                 return;         /* nothing to do */
 786         } else {
 787                 ND_PRINT((ndo, " Unknown Version, neither L2F(1) nor L2TP(2)"));
 788                 return;         /* nothing we can do */
 789         }
 790
 791         ND_PRINT((ndo, "["));
 792         if (EXTRACT_BE_U_2(ptr) & L2TP_FLAG_TYPE) {
 793                 flag_t = TRUE;
 794                 ND_PRINT((ndo, "T"));
 795         }
 796         if (EXTRACT_BE_U_2(ptr) & L2TP_FLAG_LENGTH) {
 797                 flag_l = TRUE;
 798                 ND_PRINT((ndo, "L"));
 799         }
 800         if (EXTRACT_BE_U_2(ptr) & L2TP_FLAG_SEQUENCE) {
 801                 flag_s = TRUE;
 802                 ND_PRINT((ndo, "S"));
 803         }
 804         if (EXTRACT_BE_U_2(ptr) & L2TP_FLAG_OFFSET) {
 805                 flag_o = TRUE;
 806                 ND_PRINT((ndo, "O"));
 807         }
 808         if (EXTRACT_BE_U_2(ptr) & L2TP_FLAG_PRIORITY)
 809                 ND_PRINT((ndo, "P"));
 810         ND_PRINT((ndo, "]"));
 811
 812         ptr += 2;
 813         cnt += 2;
 814
 815         if (flag_l) {
 816                 ND_TCHECK_2(ptr);       /* Length */
 817                 l2tp_len = EXTRACT_BE_U_2(ptr);
 818                 ptr += 2;
 819                 cnt += 2;
 820         } else {
 821                 l2tp_len = 0;
 822         }
 823
 824         ND_TCHECK_2(ptr);               /* Tunnel ID */
 825         ND_PRINT((ndo, "(%u/", EXTRACT_BE_U_2(ptr)));
 826         ptr += 2;
 827         cnt += 2;
 828         ND_TCHECK_2(ptr);               /* Session ID */
 829         ND_PRINT((ndo, "%u)",  EXTRACT_BE_U_2(ptr)));
 830         ptr += 2;
 831         cnt += 2;
 832
 833         if (flag_s) {
 834                 ND_TCHECK_2(ptr);       /* Ns */
 835                 ND_PRINT((ndo, "Ns=%u,", EXTRACT_BE_U_2(ptr)));
 836                 ptr += 2;
 837                 cnt += 2;
 838                 ND_TCHECK_2(ptr);       /* Nr */
 839                 ND_PRINT((ndo, "Nr=%u",  EXTRACT_BE_U_2(ptr)));
 840                 ptr += 2;
 841                 cnt += 2;
 842         }
 843
 844         if (flag_o) {
 845                 ND_TCHECK_2(ptr);       /* Offset Size */
 846                 pad =  EXTRACT_BE_U_2(ptr);
 847                 ptr += (2 + pad);
 848                 cnt += (2 + pad);
 849         }
 850
 851         if (flag_l) {
 852                 if (length < l2tp_len) {
 853                         ND_PRINT((ndo, " Length %u larger than packet", l2tp_len));
 854                         return;
 855                 }
 856                 length = l2tp_len;
 857         }
 858         if (length < cnt) {
 859                 ND_PRINT((ndo, " Length %u smaller than header length", length));
 860                 return;
 861         }
 862         if (flag_t) {
 863                 if (!flag_l) {
 864                         ND_PRINT((ndo, " No length"));
 865                         return;
 866                 }
 867                 if (length - cnt == 0) {
 868                         ND_PRINT((ndo, " ZLB"));
 869                 } else {
 870                         l2tp_avp_print(ndo, ptr, length - cnt);
 871                 }
 872         } else {
 873                 ND_PRINT((ndo, " {"));
 874                 ppp_print(ndo, ptr, length - cnt);
 875                 ND_PRINT((ndo, "}"));
 876         }
 877
 878         return;
 879
 880  trunc:
 881         ND_PRINT((ndo, "%s", tstr));
 882 }