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 #define NETDISSECT_REWORKED
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28
  29 #include <tcpdump-stdinc.h>
  30
  31 #include "interface.h"
  32 #include "extract.h"
  33
  34 #define L2TP_FLAG_TYPE          0x8000  /* Type (0=Data, 1=Control) */
  35 #define L2TP_FLAG_LENGTH        0x4000  /* Length */
  36 #define L2TP_FLAG_SEQUENCE      0x0800  /* Sequence */
  37 #define L2TP_FLAG_OFFSET        0x0200  /* Offset */
  38 #define L2TP_FLAG_PRIORITY      0x0100  /* Priority */
  39
  40 #define L2TP_VERSION_MASK       0x000f  /* Version Mask */
  41 #define L2TP_VERSION_L2F        0x0001  /* L2F */
  42 #define L2TP_VERSION_L2TP       0x0002  /* L2TP */
  43
  44 #define L2TP_AVP_HDR_FLAG_MANDATORY     0x8000  /* Mandatory Flag */
  45 #define L2TP_AVP_HDR_FLAG_HIDDEN        0x4000  /* Hidden Flag */
  46 #define L2TP_AVP_HDR_LEN_MASK           0x03ff  /* Length Mask */
  47
  48 #define L2TP_FRAMING_CAP_SYNC_MASK      0x00000001      /* Synchronous */
  49 #define L2TP_FRAMING_CAP_ASYNC_MASK     0x00000002      /* Asynchronous */
  50
  51 #define L2TP_FRAMING_TYPE_SYNC_MASK     0x00000001      /* Synchronous */
  52 #define L2TP_FRAMING_TYPE_ASYNC_MASK    0x00000002      /* Asynchronous */
  53
  54 #define L2TP_BEARER_CAP_DIGITAL_MASK    0x00000001      /* Digital */
  55 #define L2TP_BEARER_CAP_ANALOG_MASK     0x00000002      /* Analog */
  56
  57 #define L2TP_BEARER_TYPE_DIGITAL_MASK   0x00000001      /* Digital */
  58 #define L2TP_BEARER_TYPE_ANALOG_MASK    0x00000002      /* Analog */
  59
  60 /* Authen Type */
  61 #define L2TP_AUTHEN_TYPE_RESERVED       0x0000  /* Reserved */
  62 #define L2TP_AUTHEN_TYPE_TEXTUAL        0x0001  /* Textual username/password exchange */
  63 #define L2TP_AUTHEN_TYPE_CHAP           0x0002  /* PPP CHAP */
  64 #define L2TP_AUTHEN_TYPE_PAP            0x0003  /* PPP PAP */
  65 #define L2TP_AUTHEN_TYPE_NO_AUTH        0x0004  /* No Authentication */
  66 #define L2TP_AUTHEN_TYPE_MSCHAPv1       0x0005  /* MSCHAPv1 */
  67
  68 #define L2TP_PROXY_AUTH_ID_MASK         0x00ff
  69
  70 static const char tstr[] = " [|l2tp]";
  71
  72 #define L2TP_MSGTYPE_SCCRQ      1  /* Start-Control-Connection-Request */
  73 #define L2TP_MSGTYPE_SCCRP      2  /* Start-Control-Connection-Reply */
  74 #define L2TP_MSGTYPE_SCCCN      3  /* Start-Control-Connection-Connected */
  75 #define L2TP_MSGTYPE_STOPCCN    4  /* Stop-Control-Connection-Notification */
  76 #define L2TP_MSGTYPE_HELLO      6  /* Hello */
  77 #define L2TP_MSGTYPE_OCRQ       7  /* Outgoing-Call-Request */
  78 #define L2TP_MSGTYPE_OCRP       8  /* Outgoing-Call-Reply */
  79 #define L2TP_MSGTYPE_OCCN       9  /* Outgoing-Call-Connected */
  80 #define L2TP_MSGTYPE_ICRQ       10 /* Incoming-Call-Request */
  81 #define L2TP_MSGTYPE_ICRP       11 /* Incoming-Call-Reply */
  82 #define L2TP_MSGTYPE_ICCN       12 /* Incoming-Call-Connected */
  83 #define L2TP_MSGTYPE_CDN        14 /* Call-Disconnect-Notify */
  84 #define L2TP_MSGTYPE_WEN        15 /* WAN-Error-Notify */
  85 #define L2TP_MSGTYPE_SLI        16 /* Set-Link-Info */
  86
  87 static const struct tok l2tp_msgtype2str[] = {
  88         { L2TP_MSGTYPE_SCCRQ,   "SCCRQ" },
  89         { L2TP_MSGTYPE_SCCRP,   "SCCRP" },
  90         { L2TP_MSGTYPE_SCCCN,   "SCCCN" },
  91         { L2TP_MSGTYPE_STOPCCN, "StopCCN" },
  92         { L2TP_MSGTYPE_HELLO,   "HELLO" },
  93         { L2TP_MSGTYPE_OCRQ,    "OCRQ" },
  94         { L2TP_MSGTYPE_OCRP,    "OCRP" },
  95         { L2TP_MSGTYPE_OCCN,    "OCCN" },
  96         { L2TP_MSGTYPE_ICRQ,    "ICRQ" },
  97         { L2TP_MSGTYPE_ICRP,    "ICRP" },
  98         { L2TP_MSGTYPE_ICCN,    "ICCN" },
  99         { L2TP_MSGTYPE_CDN,     "CDN" },
 100         { L2TP_MSGTYPE_WEN,     "WEN" },
 101         { L2TP_MSGTYPE_SLI,     "SLI" },
 102         { 0,                    NULL }
 103 };
 104
 105 #define L2TP_AVP_MSGTYPE                0  /* Message Type */
 106 #define L2TP_AVP_RESULT_CODE            1  /* Result Code */
 107 #define L2TP_AVP_PROTO_VER              2  /* Protocol Version */
 108 #define L2TP_AVP_FRAMING_CAP            3  /* Framing Capabilities */
 109 #define L2TP_AVP_BEARER_CAP             4  /* Bearer Capabilities */
 110 #define L2TP_AVP_TIE_BREAKER            5  /* Tie Breaker */
 111 #define L2TP_AVP_FIRM_VER               6  /* Firmware Revision */
 112 #define L2TP_AVP_HOST_NAME              7  /* Host Name */
 113 #define L2TP_AVP_VENDOR_NAME            8  /* Vendor Name */
 114 #define L2TP_AVP_ASSND_TUN_ID           9  /* Assigned Tunnel ID */
 115 #define L2TP_AVP_RECV_WIN_SIZE          10 /* Receive Window Size */
 116 #define L2TP_AVP_CHALLENGE              11 /* Challenge */
 117 #define L2TP_AVP_Q931_CC                12 /* Q.931 Cause Code */
 118 #define L2TP_AVP_CHALLENGE_RESP         13 /* Challenge Response */
 119 #define L2TP_AVP_ASSND_SESS_ID          14 /* Assigned Session ID */
 120 #define L2TP_AVP_CALL_SER_NUM           15 /* Call Serial Number */
 121 #define L2TP_AVP_MINIMUM_BPS            16 /* Minimum BPS */
 122 #define L2TP_AVP_MAXIMUM_BPS            17 /* Maximum BPS */
 123 #define L2TP_AVP_BEARER_TYPE            18 /* Bearer Type */
 124 #define L2TP_AVP_FRAMING_TYPE           19 /* Framing Type */
 125 #define L2TP_AVP_PACKET_PROC_DELAY      20 /* Packet Processing Delay (OBSOLETE) */
 126 #define L2TP_AVP_CALLED_NUMBER          21 /* Called Number */
 127 #define L2TP_AVP_CALLING_NUMBER         22 /* Calling Number */
 128 #define L2TP_AVP_SUB_ADDRESS            23 /* Sub-Address */
 129 #define L2TP_AVP_TX_CONN_SPEED          24 /* (Tx) Connect Speed */
 130 #define L2TP_AVP_PHY_CHANNEL_ID         25 /* Physical Channel ID */
 131 #define L2TP_AVP_INI_RECV_LCP           26 /* Initial Received LCP CONFREQ */
 132 #define L2TP_AVP_LAST_SENT_LCP          27 /* Last Sent LCP CONFREQ */
 133 #define L2TP_AVP_LAST_RECV_LCP          28 /* Last Received LCP CONFREQ */
 134 #define L2TP_AVP_PROXY_AUTH_TYPE        29 /* Proxy Authen Type */
 135 #define L2TP_AVP_PROXY_AUTH_NAME        30 /* Proxy Authen Name */
 136 #define L2TP_AVP_PROXY_AUTH_CHAL        31 /* Proxy Authen Challenge */
 137 #define L2TP_AVP_PROXY_AUTH_ID          32 /* Proxy Authen ID */
 138 #define L2TP_AVP_PROXY_AUTH_RESP        33 /* Proxy Authen Response */
 139 #define L2TP_AVP_CALL_ERRORS            34 /* Call Errors */
 140 #define L2TP_AVP_ACCM                   35 /* ACCM */
 141 #define L2TP_AVP_RANDOM_VECTOR          36 /* Random Vector */
 142 #define L2TP_AVP_PRIVATE_GRP_ID         37 /* Private Group ID */
 143 #define L2TP_AVP_RX_CONN_SPEED          38 /* (Rx) Connect Speed */
 144 #define L2TP_AVP_SEQ_REQUIRED           39 /* Sequencing Required */
 145 #define L2TP_AVP_PPP_DISCON_CC          46 /* PPP Disconnect Cause Code */
 146
 147 static const struct tok l2tp_avp2str[] = {
 148         { L2TP_AVP_MSGTYPE,             "MSGTYPE" },
 149         { L2TP_AVP_RESULT_CODE,         "RESULT_CODE" },
 150         { L2TP_AVP_PROTO_VER,           "PROTO_VER" },
 151         { L2TP_AVP_FRAMING_CAP,         "FRAMING_CAP" },
 152         { L2TP_AVP_BEARER_CAP,          "BEARER_CAP" },
 153         { L2TP_AVP_TIE_BREAKER,         "TIE_BREAKER" },
 154         { L2TP_AVP_FIRM_VER,            "FIRM_VER" },
 155         { L2TP_AVP_HOST_NAME,           "HOST_NAME" },
 156         { L2TP_AVP_VENDOR_NAME,         "VENDOR_NAME" },
 157         { L2TP_AVP_ASSND_TUN_ID,        "ASSND_TUN_ID" },
 158         { L2TP_AVP_RECV_WIN_SIZE,       "RECV_WIN_SIZE" },
 159         { L2TP_AVP_CHALLENGE,           "CHALLENGE" },
 160         { L2TP_AVP_Q931_CC,             "Q931_CC", },
 161         { L2TP_AVP_CHALLENGE_RESP,      "CHALLENGE_RESP" },
 162         { L2TP_AVP_ASSND_SESS_ID,       "ASSND_SESS_ID" },
 163         { L2TP_AVP_CALL_SER_NUM,        "CALL_SER_NUM" },
 164         { L2TP_AVP_MINIMUM_BPS,         "MINIMUM_BPS" },
 165         { L2TP_AVP_MAXIMUM_BPS,         "MAXIMUM_BPS" },
 166         { L2TP_AVP_BEARER_TYPE,         "BEARER_TYPE" },
 167         { L2TP_AVP_FRAMING_TYPE,        "FRAMING_TYPE" },
 168         { L2TP_AVP_PACKET_PROC_DELAY,   "PACKET_PROC_DELAY" },
 169         { L2TP_AVP_CALLED_NUMBER,       "CALLED_NUMBER" },
 170         { L2TP_AVP_CALLING_NUMBER,      "CALLING_NUMBER" },
 171         { L2TP_AVP_SUB_ADDRESS,         "SUB_ADDRESS" },
 172         { L2TP_AVP_TX_CONN_SPEED,       "TX_CONN_SPEED" },
 173         { L2TP_AVP_PHY_CHANNEL_ID,      "PHY_CHANNEL_ID" },
 174         { L2TP_AVP_INI_RECV_LCP,        "INI_RECV_LCP" },
 175         { L2TP_AVP_LAST_SENT_LCP,       "LAST_SENT_LCP" },
 176         { L2TP_AVP_LAST_RECV_LCP,       "LAST_RECV_LCP" },
 177         { L2TP_AVP_PROXY_AUTH_TYPE,     "PROXY_AUTH_TYPE" },
 178         { L2TP_AVP_PROXY_AUTH_NAME,     "PROXY_AUTH_NAME" },
 179         { L2TP_AVP_PROXY_AUTH_CHAL,     "PROXY_AUTH_CHAL" },
 180         { L2TP_AVP_PROXY_AUTH_ID,       "PROXY_AUTH_ID" },
 181         { L2TP_AVP_PROXY_AUTH_RESP,     "PROXY_AUTH_RESP" },
 182         { L2TP_AVP_CALL_ERRORS,         "CALL_ERRORS" },
 183         { L2TP_AVP_ACCM,                "ACCM" },
 184         { L2TP_AVP_RANDOM_VECTOR,       "RANDOM_VECTOR" },
 185         { L2TP_AVP_PRIVATE_GRP_ID,      "PRIVATE_GRP_ID" },
 186         { L2TP_AVP_RX_CONN_SPEED,       "RX_CONN_SPEED" },
 187         { L2TP_AVP_SEQ_REQUIRED,        "SEQ_REQUIRED" },
 188         { L2TP_AVP_PPP_DISCON_CC,       "PPP_DISCON_CC" },
 189         { 0,                            NULL }
 190 };
 191
 192 static const struct tok l2tp_authentype2str[] = {
 193         { L2TP_AUTHEN_TYPE_RESERVED,    "Reserved" },
 194         { L2TP_AUTHEN_TYPE_TEXTUAL,     "Textual" },
 195         { L2TP_AUTHEN_TYPE_CHAP,        "CHAP" },
 196         { L2TP_AUTHEN_TYPE_PAP,         "PAP" },
 197         { L2TP_AUTHEN_TYPE_NO_AUTH,     "No Auth" },
 198         { L2TP_AUTHEN_TYPE_MSCHAPv1,    "MS-CHAPv1" },
 199         { 0,                            NULL }
 200 };
 201
 202 #define L2TP_PPP_DISCON_CC_DIRECTION_GLOBAL     0
 203 #define L2TP_PPP_DISCON_CC_DIRECTION_AT_PEER    1
 204 #define L2TP_PPP_DISCON_CC_DIRECTION_AT_LOCAL   2
 205
 206 static const struct tok l2tp_cc_direction2str[] = {
 207         { L2TP_PPP_DISCON_CC_DIRECTION_GLOBAL,  "global error" },
 208         { L2TP_PPP_DISCON_CC_DIRECTION_AT_PEER, "at peer" },
 209         { L2TP_PPP_DISCON_CC_DIRECTION_AT_LOCAL,"at local" },
 210         { 0,                                    NULL }
 211 };
 212
 213 #if 0
 214 static char *l2tp_result_code_StopCCN[] = {
 215          "Reserved",
 216          "General request to clear control connection",
 217          "General error--Error Code indicates the problem",
 218          "Control channel already exists",
 219          "Requester is not authorized to establish a control channel",
 220          "The protocol version of the requester is not supported",
 221          "Requester is being shut down",
 222          "Finite State Machine error"
 223 #define L2TP_MAX_RESULT_CODE_STOPCC_INDEX       8
 224 };
 225 #endif
 226
 227 #if 0
 228 static char *l2tp_result_code_CDN[] = {
 229         "Reserved",
 230         "Call disconnected due to loss of carrier",
 231         "Call disconnected for the reason indicated in error code",
 232         "Call disconnected for administrative reasons",
 233         "Call failed due to lack of appropriate facilities being " \
 234         "available (temporary condition)",
 235         "Call failed due to lack of appropriate facilities being " \
 236         "available (permanent condition)",
 237         "Invalid destination",
 238         "Call failed due to no carrier detected",
 239         "Call failed due to detection of a busy signal",
 240         "Call failed due to lack of a dial tone",
 241         "Call was not established within time allotted by LAC",
 242         "Call was connected but no appropriate framing was detected"
 243 #define L2TP_MAX_RESULT_CODE_CDN_INDEX  12
 244 };
 245 #endif
 246
 247 #if 0
 248 static char *l2tp_error_code_general[] = {
 249         "No general error",
 250         "No control connection exists yet for this LAC-LNS pair",
 251         "Length is wrong",
 252         "One of the field values was out of range or " \
 253         "reserved field was non-zero"
 254         "Insufficient resources to handle this operation now",
 255         "The Session ID is invalid in this context",
 256         "A generic vendor-specific error occurred in the LAC",
 257         "Try another"
 258 #define L2TP_MAX_ERROR_CODE_GENERAL_INDEX       8
 259 };
 260 #endif
 261
 262 /******************************/
 263 /* generic print out routines */
 264 /******************************/
 265 static void
 266 print_string(netdissect_options *ndo, const u_char *dat, u_int length)
 267 {
 268         u_int i;
 269         for (i=0; i<length; i++) {
 270                 ND_PRINT((ndo, "%c", *dat++));
 271         }
 272 }
 273
 274 static void
 275 print_octets(netdissect_options *ndo, const u_char *dat, u_int length)
 276 {
 277         u_int i;
 278         for (i=0; i<length; i++) {
 279                 ND_PRINT((ndo, "%02x", *dat++));
 280         }
 281 }
 282
 283 static void
 284 print_16bits_val(netdissect_options *ndo, const uint16_t *dat)
 285 {
 286         ND_PRINT((ndo, "%u", EXTRACT_16BITS(dat)));
 287 }
 288
 289 static void
 290 print_32bits_val(netdissect_options *ndo, const uint32_t *dat)
 291 {
 292         ND_PRINT((ndo, "%lu", (u_long)EXTRACT_32BITS(dat)));
 293 }
 294
 295 /***********************************/
 296 /* AVP-specific print out routines */
 297 /***********************************/
 298 static void
 299 l2tp_msgtype_print(netdissect_options *ndo, const u_char *dat)
 300 {
 301         uint16_t *ptr = (uint16_t*)dat;
 302
 303         ND_PRINT((ndo, "%s", tok2str(l2tp_msgtype2str, "MSGTYPE-#%u",
 304             EXTRACT_16BITS(ptr))));
 305 }
 306
 307 static void
 308 l2tp_result_code_print(netdissect_options *ndo, const u_char *dat, u_int length)
 309 {
 310         uint16_t *ptr = (uint16_t *)dat;
 311
 312         ND_PRINT((ndo, "%u", EXTRACT_16BITS(ptr))); ptr++;      /* Result Code */
 313         if (length > 2) {                               /* Error Code (opt) */
 314                 ND_PRINT((ndo, "/%u", EXTRACT_16BITS(ptr))); ptr++;
 315         }
 316         if (length > 4) {                               /* Error Message (opt) */
 317                 ND_PRINT((ndo, " "));
 318                 print_string(ndo, (u_char *)ptr, length - 4);
 319         }
 320 }
 321
 322 static void
 323 l2tp_proto_ver_print(netdissect_options *ndo, const uint16_t *dat)
 324 {
 325         ND_PRINT((ndo, "%u.%u", (EXTRACT_16BITS(dat) >> 8),
 326             (EXTRACT_16BITS(dat) & 0xff)));
 327 }
 328
 329 static void
 330 l2tp_framing_cap_print(netdissect_options *ndo, const u_char *dat)
 331 {
 332         uint32_t *ptr = (uint32_t *)dat;
 333
 334         if (EXTRACT_32BITS(ptr) &  L2TP_FRAMING_CAP_ASYNC_MASK) {
 335                 ND_PRINT((ndo, "A"));
 336         }
 337         if (EXTRACT_32BITS(ptr) &  L2TP_FRAMING_CAP_SYNC_MASK) {
 338                 ND_PRINT((ndo, "S"));
 339         }
 340 }
 341
 342 static void
 343 l2tp_bearer_cap_print(netdissect_options *ndo, const u_char *dat)
 344 {
 345         uint32_t *ptr = (uint32_t *)dat;
 346
 347         if (EXTRACT_32BITS(ptr) &  L2TP_BEARER_CAP_ANALOG_MASK) {
 348                 ND_PRINT((ndo, "A"));
 349         }
 350         if (EXTRACT_32BITS(ptr) &  L2TP_BEARER_CAP_DIGITAL_MASK) {
 351                 ND_PRINT((ndo, "D"));
 352         }
 353 }
 354
 355 static void
 356 l2tp_q931_cc_print(netdissect_options *ndo, const u_char *dat, u_int length)
 357 {
 358         print_16bits_val(ndo, (uint16_t *)dat);
 359         ND_PRINT((ndo, ", %02x", dat[2]));
 360         if (length > 3) {
 361                 ND_PRINT((ndo, " "));
 362                 print_string(ndo, dat+3, length-3);
 363         }
 364 }
 365
 366 static void
 367 l2tp_bearer_type_print(netdissect_options *ndo, const u_char *dat)
 368 {
 369         uint32_t *ptr = (uint32_t *)dat;
 370
 371         if (EXTRACT_32BITS(ptr) &  L2TP_BEARER_TYPE_ANALOG_MASK) {
 372                 ND_PRINT((ndo, "A"));
 373         }
 374         if (EXTRACT_32BITS(ptr) &  L2TP_BEARER_TYPE_DIGITAL_MASK) {
 375                 ND_PRINT((ndo, "D"));
 376         }
 377 }
 378
 379 static void
 380 l2tp_framing_type_print(netdissect_options *ndo, const u_char *dat)
 381 {
 382         uint32_t *ptr = (uint32_t *)dat;
 383
 384         if (EXTRACT_32BITS(ptr) &  L2TP_FRAMING_TYPE_ASYNC_MASK) {
 385                 ND_PRINT((ndo, "A"));
 386         }
 387         if (EXTRACT_32BITS(ptr) &  L2TP_FRAMING_TYPE_SYNC_MASK) {
 388                 ND_PRINT((ndo, "S"));
 389         }
 390 }
 391
 392 static void
 393 l2tp_packet_proc_delay_print(netdissect_options *ndo)
 394 {
 395         ND_PRINT((ndo, "obsolete"));
 396 }
 397
 398 static void
 399 l2tp_proxy_auth_type_print(netdissect_options *ndo, const u_char *dat)
 400 {
 401         uint16_t *ptr = (uint16_t *)dat;
 402
 403         ND_PRINT((ndo, "%s", tok2str(l2tp_authentype2str,
 404                              "AuthType-#%u", EXTRACT_16BITS(ptr))));
 405 }
 406
 407 static void
 408 l2tp_proxy_auth_id_print(netdissect_options *ndo, const u_char *dat)
 409 {
 410         uint16_t *ptr = (uint16_t *)dat;
 411
 412         ND_PRINT((ndo, "%u", EXTRACT_16BITS(ptr) & L2TP_PROXY_AUTH_ID_MASK));
 413 }
 414
 415 static void
 416 l2tp_call_errors_print(netdissect_options *ndo, const u_char *dat)
 417 {
 418         uint16_t *ptr = (uint16_t *)dat;
 419         uint16_t val_h, val_l;
 420
 421         ptr++;          /* skip "Reserved" */
 422
 423         val_h = EXTRACT_16BITS(ptr); ptr++;
 424         val_l = EXTRACT_16BITS(ptr); ptr++;
 425         ND_PRINT((ndo, "CRCErr=%u ", (val_h<<16) + val_l));
 426
 427         val_h = EXTRACT_16BITS(ptr); ptr++;
 428         val_l = EXTRACT_16BITS(ptr); ptr++;
 429         ND_PRINT((ndo, "FrameErr=%u ", (val_h<<16) + val_l));
 430
 431         val_h = EXTRACT_16BITS(ptr); ptr++;
 432         val_l = EXTRACT_16BITS(ptr); ptr++;
 433         ND_PRINT((ndo, "HardOver=%u ", (val_h<<16) + val_l));
 434
 435         val_h = EXTRACT_16BITS(ptr); ptr++;
 436         val_l = EXTRACT_16BITS(ptr); ptr++;
 437         ND_PRINT((ndo, "BufOver=%u ", (val_h<<16) + val_l));
 438
 439         val_h = EXTRACT_16BITS(ptr); ptr++;
 440         val_l = EXTRACT_16BITS(ptr); ptr++;
 441         ND_PRINT((ndo, "Timeout=%u ", (val_h<<16) + val_l));
 442
 443         val_h = EXTRACT_16BITS(ptr); ptr++;
 444         val_l = EXTRACT_16BITS(ptr); ptr++;
 445         ND_PRINT((ndo, "AlignErr=%u ", (val_h<<16) + val_l));
 446 }
 447
 448 static void
 449 l2tp_accm_print(netdissect_options *ndo, const u_char *dat)
 450 {
 451         uint16_t *ptr = (uint16_t *)dat;
 452         uint16_t val_h, val_l;
 453
 454         ptr++;          /* skip "Reserved" */
 455
 456         val_h = EXTRACT_16BITS(ptr); ptr++;
 457         val_l = EXTRACT_16BITS(ptr); ptr++;
 458         ND_PRINT((ndo, "send=%08x ", (val_h<<16) + val_l));
 459
 460         val_h = EXTRACT_16BITS(ptr); ptr++;
 461         val_l = EXTRACT_16BITS(ptr); ptr++;
 462         ND_PRINT((ndo, "recv=%08x ", (val_h<<16) + val_l));
 463 }
 464
 465 static void
 466 l2tp_ppp_discon_cc_print(netdissect_options *ndo, const u_char *dat, u_int length)
 467 {
 468         uint16_t *ptr = (uint16_t *)dat;
 469
 470         ND_PRINT((ndo, "%04x, ", EXTRACT_16BITS(ptr))); ptr++;  /* Disconnect Code */
 471         ND_PRINT((ndo, "%04x ",  EXTRACT_16BITS(ptr))); ptr++;  /* Control Protocol Number */
 472         ND_PRINT((ndo, "%s", tok2str(l2tp_cc_direction2str,
 473                              "Direction-#%u", *((u_char *)ptr++))));
 474
 475         if (length > 5) {
 476                 ND_PRINT((ndo, " "));
 477                 print_string(ndo, (const u_char *)ptr, length-5);
 478         }
 479 }
 480
 481 static void
 482 l2tp_avp_print(netdissect_options *ndo, const u_char *dat, int length)
 483 {
 484         u_int len;
 485         const uint16_t *ptr = (uint16_t *)dat;
 486         uint16_t attr_type;
 487         int hidden = FALSE;
 488
 489         if (length <= 0) {
 490                 return;
 491         }
 492
 493         ND_PRINT((ndo, " "));
 494
 495         ND_TCHECK(*ptr);        /* Flags & Length */
 496         len = EXTRACT_16BITS(ptr) & L2TP_AVP_HDR_LEN_MASK;
 497
 498         /* If it is not long enough to contain the header, we'll give up. */
 499         if (len < 6)
 500                 goto trunc;
 501
 502         /* If it goes past the end of the remaining length of the packet,
 503            we'll give up. */
 504         if (len > (u_int)length)
 505                 goto trunc;
 506
 507         /* If it goes past the end of the remaining length of the captured
 508            data, we'll give up. */
 509         ND_TCHECK2(*ptr, len);
 510         /* After this point, no need to worry about truncation */
 511
 512         if (EXTRACT_16BITS(ptr) & L2TP_AVP_HDR_FLAG_MANDATORY) {
 513                 ND_PRINT((ndo, "*"));
 514         }
 515         if (EXTRACT_16BITS(ptr) & L2TP_AVP_HDR_FLAG_HIDDEN) {
 516                 hidden = TRUE;
 517                 ND_PRINT((ndo, "?"));
 518         }
 519         ptr++;
 520
 521         if (EXTRACT_16BITS(ptr)) {
 522                 /* Vendor Specific Attribute */
 523                 ND_PRINT((ndo, "VENDOR%04x:", EXTRACT_16BITS(ptr))); ptr++;
 524                 ND_PRINT((ndo, "ATTR%04x", EXTRACT_16BITS(ptr))); ptr++;
 525                 ND_PRINT((ndo, "("));
 526                 print_octets(ndo, (u_char *)ptr, len-6);
 527                 ND_PRINT((ndo, ")"));
 528         } else {
 529                 /* IETF-defined Attributes */
 530                 ptr++;
 531                 attr_type = EXTRACT_16BITS(ptr); ptr++;
 532                 ND_PRINT((ndo, "%s", tok2str(l2tp_avp2str, "AVP-#%u", attr_type)));
 533                 ND_PRINT((ndo, "("));
 534                 if (hidden) {
 535                         ND_PRINT((ndo, "???"));
 536                 } else {
 537                         switch (attr_type) {
 538                         case L2TP_AVP_MSGTYPE:
 539                                 l2tp_msgtype_print(ndo, (u_char *)ptr);
 540                                 break;
 541                         case L2TP_AVP_RESULT_CODE:
 542                                 l2tp_result_code_print(ndo, (u_char *)ptr, len-6);
 543                                 break;
 544                         case L2TP_AVP_PROTO_VER:
 545                                 l2tp_proto_ver_print(ndo, ptr);
 546                                 break;
 547                         case L2TP_AVP_FRAMING_CAP:
 548                                 l2tp_framing_cap_print(ndo, (u_char *)ptr);
 549                                 break;
 550                         case L2TP_AVP_BEARER_CAP:
 551                                 l2tp_bearer_cap_print(ndo, (u_char *)ptr);
 552                                 break;
 553                         case L2TP_AVP_TIE_BREAKER:
 554                                 print_octets(ndo, (u_char *)ptr, 8);
 555                                 break;
 556                         case L2TP_AVP_FIRM_VER:
 557                         case L2TP_AVP_ASSND_TUN_ID:
 558                         case L2TP_AVP_RECV_WIN_SIZE:
 559                         case L2TP_AVP_ASSND_SESS_ID:
 560                                 print_16bits_val(ndo, ptr);
 561                                 break;
 562                         case L2TP_AVP_HOST_NAME:
 563                         case L2TP_AVP_VENDOR_NAME:
 564                         case L2TP_AVP_CALLING_NUMBER:
 565                         case L2TP_AVP_CALLED_NUMBER:
 566                         case L2TP_AVP_SUB_ADDRESS:
 567                         case L2TP_AVP_PROXY_AUTH_NAME:
 568                         case L2TP_AVP_PRIVATE_GRP_ID:
 569                                 print_string(ndo, (u_char *)ptr, len-6);
 570                                 break;
 571                         case L2TP_AVP_CHALLENGE:
 572                         case L2TP_AVP_INI_RECV_LCP:
 573                         case L2TP_AVP_LAST_SENT_LCP:
 574                         case L2TP_AVP_LAST_RECV_LCP:
 575                         case L2TP_AVP_PROXY_AUTH_CHAL:
 576                         case L2TP_AVP_PROXY_AUTH_RESP:
 577                         case L2TP_AVP_RANDOM_VECTOR:
 578                                 print_octets(ndo, (u_char *)ptr, len-6);
 579                                 break;
 580                         case L2TP_AVP_Q931_CC:
 581                                 l2tp_q931_cc_print(ndo, (u_char *)ptr, len-6);
 582                                 break;
 583                         case L2TP_AVP_CHALLENGE_RESP:
 584                                 print_octets(ndo, (u_char *)ptr, 16);
 585                                 break;
 586                         case L2TP_AVP_CALL_SER_NUM:
 587                         case L2TP_AVP_MINIMUM_BPS:
 588                         case L2TP_AVP_MAXIMUM_BPS:
 589                         case L2TP_AVP_TX_CONN_SPEED:
 590                         case L2TP_AVP_PHY_CHANNEL_ID:
 591                         case L2TP_AVP_RX_CONN_SPEED:
 592                                 print_32bits_val(ndo, (uint32_t *)ptr);
 593                                 break;
 594                         case L2TP_AVP_BEARER_TYPE:
 595                                 l2tp_bearer_type_print(ndo, (u_char *)ptr);
 596                                 break;
 597                         case L2TP_AVP_FRAMING_TYPE:
 598                                 l2tp_framing_type_print(ndo, (u_char *)ptr);
 599                                 break;
 600                         case L2TP_AVP_PACKET_PROC_DELAY:
 601                                 l2tp_packet_proc_delay_print(ndo);
 602                                 break;
 603                         case L2TP_AVP_PROXY_AUTH_TYPE:
 604                                 l2tp_proxy_auth_type_print(ndo, (u_char *)ptr);
 605                                 break;
 606                         case L2TP_AVP_PROXY_AUTH_ID:
 607                                 l2tp_proxy_auth_id_print(ndo, (u_char *)ptr);
 608                                 break;
 609                         case L2TP_AVP_CALL_ERRORS:
 610                                 l2tp_call_errors_print(ndo, (u_char *)ptr);
 611                                 break;
 612                         case L2TP_AVP_ACCM:
 613                                 l2tp_accm_print(ndo, (u_char *)ptr);
 614                                 break;
 615                         case L2TP_AVP_SEQ_REQUIRED:
 616                                 break;  /* No Attribute Value */
 617                         case L2TP_AVP_PPP_DISCON_CC:
 618                                 l2tp_ppp_discon_cc_print(ndo, (u_char *)ptr, len-6);
 619                                 break;
 620                         default:
 621                                 break;
 622                         }
 623                 }
 624                 ND_PRINT((ndo, ")"));
 625         }
 626
 627         l2tp_avp_print(ndo, dat+len, length-len);
 628         return;
 629
 630  trunc:
 631         ND_PRINT((ndo, "|..."));
 632 }
 633
 634
 635 void
 636 l2tp_print(netdissect_options *ndo, const u_char *dat, u_int length)
 637 {
 638         const u_char *ptr = dat;
 639         u_int cnt = 0;                  /* total octets consumed */
 640         uint16_t pad;
 641         int flag_t, flag_l, flag_s, flag_o;
 642         uint16_t l2tp_len;
 643
 644         flag_t = flag_l = flag_s = flag_o = FALSE;
 645
 646         ND_TCHECK2(*ptr, 2);    /* Flags & Version */
 647         if ((EXTRACT_16BITS(ptr) & L2TP_VERSION_MASK) == L2TP_VERSION_L2TP) {
 648                 ND_PRINT((ndo, " l2tp:"));
 649         } else if ((EXTRACT_16BITS(ptr) & L2TP_VERSION_MASK) == L2TP_VERSION_L2F) {
 650                 ND_PRINT((ndo, " l2f:"));
 651                 return;         /* nothing to do */
 652         } else {
 653                 ND_PRINT((ndo, " Unknown Version, neither L2F(1) nor L2TP(2)"));
 654                 return;         /* nothing we can do */
 655         }
 656
 657         ND_PRINT((ndo, "["));
 658         if (EXTRACT_16BITS(ptr) & L2TP_FLAG_TYPE) {
 659                 flag_t = TRUE;
 660                 ND_PRINT((ndo, "T"));
 661         }
 662         if (EXTRACT_16BITS(ptr) & L2TP_FLAG_LENGTH) {
 663                 flag_l = TRUE;
 664                 ND_PRINT((ndo, "L"));
 665         }
 666         if (EXTRACT_16BITS(ptr) & L2TP_FLAG_SEQUENCE) {
 667                 flag_s = TRUE;
 668                 ND_PRINT((ndo, "S"));
 669         }
 670         if (EXTRACT_16BITS(ptr) & L2TP_FLAG_OFFSET) {
 671                 flag_o = TRUE;
 672                 ND_PRINT((ndo, "O"));
 673         }
 674         if (EXTRACT_16BITS(ptr) & L2TP_FLAG_PRIORITY)
 675                 ND_PRINT((ndo, "P"));
 676         ND_PRINT((ndo, "]"));
 677
 678         ptr += 2;
 679         cnt += 2;
 680
 681         if (flag_l) {
 682                 ND_TCHECK2(*ptr, 2);    /* Length */
 683                 l2tp_len = EXTRACT_16BITS(ptr);
 684                 ptr += 2;
 685                 cnt += 2;
 686         } else {
 687                 l2tp_len = 0;
 688         }
 689
 690         ND_TCHECK2(*ptr, 2);            /* Tunnel ID */
 691         ND_PRINT((ndo, "(%u/", EXTRACT_16BITS(ptr)));
 692         ptr += 2;
 693         cnt += 2;
 694         ND_TCHECK2(*ptr, 2);            /* Session ID */
 695         ND_PRINT((ndo, "%u)",  EXTRACT_16BITS(ptr)));
 696         ptr += 2;
 697         cnt += 2;
 698
 699         if (flag_s) {
 700                 ND_TCHECK2(*ptr, 2);    /* Ns */
 701                 ND_PRINT((ndo, "Ns=%u,", EXTRACT_16BITS(ptr)));
 702                 ptr += 2;
 703                 cnt += 2;
 704                 ND_TCHECK2(*ptr, 2);    /* Nr */
 705                 ND_PRINT((ndo, "Nr=%u",  EXTRACT_16BITS(ptr)));
 706                 ptr += 2;
 707                 cnt += 2;
 708         }
 709
 710         if (flag_o) {
 711                 ND_TCHECK2(*ptr, 2);    /* Offset Size */
 712                 pad =  EXTRACT_16BITS(ptr);
 713                 ptr += (2 + pad);
 714                 cnt += (2 + pad);
 715         }
 716
 717         if (flag_l) {
 718                 if (length < l2tp_len) {
 719                         ND_PRINT((ndo, " Length %u larger than packet", l2tp_len));
 720                         return;
 721                 }
 722                 length = l2tp_len;
 723         }
 724         if (length < cnt) {
 725                 ND_PRINT((ndo, " Length %u smaller than header length", length));
 726                 return;
 727         }
 728         if (flag_t) {
 729                 if (!flag_l) {
 730                         ND_PRINT((ndo, " No length"));
 731                         return;
 732                 }
 733                 if (length - cnt == 0) {
 734                         ND_PRINT((ndo, " ZLB"));
 735                 } else {
 736                         l2tp_avp_print(ndo, ptr, length - cnt);
 737                 }
 738         } else {
 739                 ND_PRINT((ndo, " {"));
 740                 ppp_print(ndo, ptr, length - cnt);
 741                 ND_PRINT((ndo, "}"));
 742         }
 743
 744         return;
 745
 746  trunc:
 747         ND_PRINT((ndo, "%s", tstr));
 748 }