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

   1 /**
   2  * Copyright (c) 2012
   3  *
   4  * Gregory Detal <gregory.detal@uclouvain.be>
   5  * Christoph Paasch <christoph.paasch@uclouvain.be>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  *
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * 3. Neither the name of the University nor of the Laboratory may be used
  19  *    to endorse or promote products derived from this software without
  20  *    specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 /* \summary: Multipath TCP (MPTCP) printer */
  36
  37 /* specification: RFC 6824 */
  38
  39 #ifdef HAVE_CONFIG_H
  40 #include <config.h>
  41 #endif
  42
  43 #include "netdissect-stdinc.h"
  44
  45 #include "netdissect.h"
  46 #include "extract.h"
  47 #include "addrtoname.h"
  48
  49 #include "tcp.h"
  50
  51 #define MPTCP_SUB_CAPABLE       0x0
  52 #define MPTCP_SUB_JOIN          0x1
  53 #define MPTCP_SUB_DSS           0x2
  54 #define MPTCP_SUB_ADD_ADDR      0x3
  55 #define MPTCP_SUB_REMOVE_ADDR   0x4
  56 #define MPTCP_SUB_PRIO          0x5
  57 #define MPTCP_SUB_FAIL          0x6
  58 #define MPTCP_SUB_FCLOSE        0x7
  59
  60 struct mptcp_option {
  61         nd_uint8_t     kind;
  62         nd_uint8_t     len;
  63         nd_uint8_t     sub_etc;        /* subtype upper 4 bits, other stuff lower 4 bits */
  64 };
  65
  66 #define MPTCP_OPT_SUBTYPE(sub_etc)      (((sub_etc) >> 4) & 0xF)
  67
  68 struct mp_capable {
  69         nd_uint8_t     kind;
  70         nd_uint8_t     len;
  71         nd_uint8_t     sub_ver;
  72         nd_uint8_t     flags;
  73         nd_uint64_t    sender_key;
  74         nd_uint64_t    receiver_key;
  75 };
  76
  77 #define MP_CAPABLE_OPT_VERSION(sub_ver) (((sub_ver) >> 0) & 0xF)
  78 #define MP_CAPABLE_C                    0x80
  79 #define MP_CAPABLE_S                    0x01
  80
  81 struct mp_join {
  82         nd_uint8_t     kind;
  83         nd_uint8_t     len;
  84         nd_uint8_t     sub_b;
  85         nd_uint8_t     addr_id;
  86         union {
  87                 struct {
  88                         nd_uint32_t     token;
  89                         nd_uint32_t     nonce;
  90                 } syn;
  91                 struct {
  92                         nd_uint64_t     mac;
  93                         nd_uint32_t     nonce;
  94                 } synack;
  95                 struct {
  96                         nd_byte         mac[20];
  97                 } ack;
  98         } u;
  99 };
 100
 101 #define MP_JOIN_B                       0x01
 102
 103 struct mp_dss {
 104         nd_uint8_t     kind;
 105         nd_uint8_t     len;
 106         nd_uint8_t     sub;
 107         nd_uint8_t     flags;
 108 };
 109
 110 #define MP_DSS_F                        0x10
 111 #define MP_DSS_m                        0x08
 112 #define MP_DSS_M                        0x04
 113 #define MP_DSS_a                        0x02
 114 #define MP_DSS_A                        0x01
 115
 116 static const struct tok mptcp_addr_subecho_bits[] = {
 117         { 0x6, "v0-ip6" },
 118         { 0x4, "v0-ip4" },
 119         { 0x1, "v1-echo" },
 120         { 0x0, "v1" },
 121         { 0, NULL }
 122 };
 123
 124 struct mp_add_addr {
 125         nd_uint8_t     kind;
 126         nd_uint8_t     len;
 127         nd_uint8_t     sub_echo;
 128         nd_uint8_t     addr_id;
 129         union {
 130                 struct {
 131                         nd_ipv4         addr;
 132                         nd_uint16_t     port;
 133                         nd_uint64_t     mac;
 134                 } v4;
 135                 struct {
 136                         nd_ipv4         addr;
 137                         nd_uint64_t     mac;
 138                 } v4np;
 139                 struct {
 140                         nd_ipv6         addr;
 141                         nd_uint16_t     port;
 142                         nd_uint64_t     mac;
 143                 } v6;
 144                 struct {
 145                         nd_ipv6         addr;
 146                         nd_uint64_t     mac;
 147                 } v6np;
 148         } u;
 149 };
 150
 151 struct mp_remove_addr {
 152         nd_uint8_t     kind;
 153         nd_uint8_t     len;
 154         nd_uint8_t     sub;
 155         /* list of addr_id */
 156         nd_uint8_t     addrs_id[1];
 157 };
 158
 159 struct mp_fail {
 160         nd_uint8_t     kind;
 161         nd_uint8_t     len;
 162         nd_uint8_t     sub;
 163         nd_uint8_t     resv;
 164         nd_uint64_t    data_seq;
 165 };
 166
 167 struct mp_close {
 168         nd_uint8_t     kind;
 169         nd_uint8_t     len;
 170         nd_uint8_t     sub;
 171         nd_uint8_t     rsv;
 172         nd_byte        key[8];
 173 };
 174
 175 struct mp_prio {
 176         nd_uint8_t     kind;
 177         nd_uint8_t     len;
 178         nd_uint8_t     sub_b;
 179         nd_uint8_t     addr_id;
 180 };
 181
 182 #define MP_PRIO_B                       0x01
 183
 184 static int
 185 dummy_print(netdissect_options *ndo _U_,
 186             const u_char *opt _U_, u_int opt_len _U_, u_char flags _U_)
 187 {
 188         return 1;
 189 }
 190
 191 static int
 192 mp_capable_print(netdissect_options *ndo,
 193                  const u_char *opt, u_int opt_len, u_char flags)
 194 {
 195         const struct mp_capable *mpc = (const struct mp_capable *) opt;
 196         uint8_t version;
 197
 198         if (!((opt_len == 12 || opt_len == 4) && flags & TH_SYN) &&
 199             !((opt_len == 20 || opt_len == 22) && (flags & (TH_SYN | TH_ACK)) ==
 200               TH_ACK))
 201                 return 0;
 202
 203         version = MP_CAPABLE_OPT_VERSION(GET_U_1(mpc->sub_ver));
 204         switch (version) {
 205                 case 0: /* fall through */
 206                 case 1:
 207                         ND_PRINT(" v%u", version);
 208                         break;
 209                 default:
 210                         ND_PRINT(" Unknown Version (%u)", version);
 211                         return 1;
 212         }
 213
 214         if (GET_U_1(mpc->flags) & MP_CAPABLE_C)
 215                 ND_PRINT(" csum");
 216         if (opt_len == 12 || opt_len >= 20) {
 217                 ND_PRINT(" {0x%" PRIx64, GET_BE_U_8(mpc->sender_key));
 218                 if (opt_len >= 20)
 219                         ND_PRINT(",0x%" PRIx64, GET_BE_U_8(mpc->receiver_key));
 220                 ND_PRINT("}");
 221         }
 222         return 1;
 223 }
 224
 225 static int
 226 mp_join_print(netdissect_options *ndo,
 227               const u_char *opt, u_int opt_len, u_char flags)
 228 {
 229         const struct mp_join *mpj = (const struct mp_join *) opt;
 230
 231         if (!(opt_len == 12 && (flags & TH_SYN)) &&
 232             !(opt_len == 16 && (flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) &&
 233             !(opt_len == 24 && (flags & TH_ACK)))
 234                 return 0;
 235
 236         if (opt_len != 24) {
 237                 if (GET_U_1(mpj->sub_b) & MP_JOIN_B)
 238                         ND_PRINT(" backup");
 239                 ND_PRINT(" id %u", GET_U_1(mpj->addr_id));
 240         }
 241
 242         switch (opt_len) {
 243         case 12: /* SYN */
 244                 ND_PRINT(" token 0x%x" " nonce 0x%x",
 245                         GET_BE_U_4(mpj->u.syn.token),
 246                         GET_BE_U_4(mpj->u.syn.nonce));
 247                 break;
 248         case 16: /* SYN/ACK */
 249                 ND_PRINT(" hmac 0x%" PRIx64 " nonce 0x%x",
 250                         GET_BE_U_8(mpj->u.synack.mac),
 251                         GET_BE_U_4(mpj->u.synack.nonce));
 252                 break;
 253         case 24: {/* ACK */
 254                 size_t i;
 255                 ND_PRINT(" hmac 0x");
 256                 for (i = 0; i < sizeof(mpj->u.ack.mac); ++i)
 257                         ND_PRINT("%02x", mpj->u.ack.mac[i]);
 258         }
 259         default:
 260                 break;
 261         }
 262         return 1;
 263 }
 264
 265 static int
 266 mp_dss_print(netdissect_options *ndo,
 267              const u_char *opt, u_int opt_len, u_char flags)
 268 {
 269         const struct mp_dss *mdss = (const struct mp_dss *) opt;
 270         uint8_t mdss_flags;
 271
 272         /* We need the flags, at a minimum. */
 273         if (opt_len < 4)
 274                 return 0;
 275
 276         if (flags & TH_SYN)
 277                 return 0;
 278
 279         mdss_flags = GET_U_1(mdss->flags);
 280         if (mdss_flags & MP_DSS_F)
 281                 ND_PRINT(" fin");
 282
 283         opt += 4;
 284         opt_len -= 4;
 285         if (mdss_flags & MP_DSS_A) {
 286                 /* Ack present */
 287                 ND_PRINT(" ack ");
 288                 /*
 289                  * If the a flag is set, we have an 8-byte ack; if it's
 290                  * clear, we have a 4-byte ack.
 291                  */
 292                 if (mdss_flags & MP_DSS_a) {
 293                         if (opt_len < 8)
 294                                 return 0;
 295                         ND_PRINT("%" PRIu64, GET_BE_U_8(opt));
 296                         opt += 8;
 297                         opt_len -= 8;
 298                 } else {
 299                         if (opt_len < 4)
 300                                 return 0;
 301                         ND_PRINT("%u", GET_BE_U_4(opt));
 302                         opt += 4;
 303                         opt_len -= 4;
 304                 }
 305         }
 306
 307         if (mdss_flags & MP_DSS_M) {
 308                 /*
 309                  * Data Sequence Number (DSN), Subflow Sequence Number (SSN),
 310                  * Data-Level Length present, and Checksum possibly present.
 311                  */
 312                 ND_PRINT(" seq ");
 313                 /*
 314                  * If the m flag is set, we have an 8-byte NDS; if it's clear,
 315                  * we have a 4-byte DSN.
 316                  */
 317                 if (mdss_flags & MP_DSS_m) {
 318                         if (opt_len < 8)
 319                                 return 0;
 320                         ND_PRINT("%" PRIu64, GET_BE_U_8(opt));
 321                         opt += 8;
 322                         opt_len -= 8;
 323                 } else {
 324                         if (opt_len < 4)
 325                                 return 0;
 326                         ND_PRINT("%u", GET_BE_U_4(opt));
 327                         opt += 4;
 328                         opt_len -= 4;
 329                 }
 330                 if (opt_len < 4)
 331                         return 0;
 332                 ND_PRINT(" subseq %u", GET_BE_U_4(opt));
 333                 opt += 4;
 334                 opt_len -= 4;
 335                 if (opt_len < 2)
 336                         return 0;
 337                 ND_PRINT(" len %u", GET_BE_U_2(opt));
 338                 opt += 2;
 339                 opt_len -= 2;
 340
 341                 /*
 342                  * The Checksum is present only if negotiated.
 343                  * If there are at least 2 bytes left, process the next 2
 344                  * bytes as the Checksum.
 345                  */
 346                 if (opt_len >= 2) {
 347                         ND_PRINT(" csum 0x%x", GET_BE_U_2(opt));
 348                         opt_len -= 2;
 349                 }
 350         }
 351         if (opt_len != 0)
 352                 return 0;
 353         return 1;
 354 }
 355
 356 static int
 357 add_addr_print(netdissect_options *ndo,
 358                const u_char *opt, u_int opt_len, u_char flags _U_)
 359 {
 360         const struct mp_add_addr *add_addr = (const struct mp_add_addr *) opt;
 361
 362         if (!(opt_len == 8 || opt_len == 10 || opt_len == 16 || opt_len == 18 ||
 363             opt_len == 20 || opt_len == 22 || opt_len == 28 || opt_len == 30))
 364                 return 0;
 365
 366         ND_PRINT(" %s",
 367                  tok2str(mptcp_addr_subecho_bits, "[bad version/echo]",
 368                          GET_U_1(add_addr->sub_echo) & 0xF));
 369         ND_PRINT(" id %u", GET_U_1(add_addr->addr_id));
 370         if (opt_len == 8 || opt_len == 10 || opt_len == 16 || opt_len == 18) {
 371                 ND_PRINT(" %s", GET_IPADDR_STRING(add_addr->u.v4.addr));
 372                 if (opt_len == 10 || opt_len == 18)
 373                         ND_PRINT(":%u", GET_BE_U_2(add_addr->u.v4.port));
 374                 if (opt_len == 16)
 375                         ND_PRINT(" hmac 0x%" PRIx64, GET_BE_U_8(add_addr->u.v4np.mac));
 376                 if (opt_len == 18)
 377                         ND_PRINT(" hmac 0x%" PRIx64, GET_BE_U_8(add_addr->u.v4.mac));
 378         }
 379
 380         if (opt_len == 20 || opt_len == 22 || opt_len == 28 || opt_len == 30) {
 381                 ND_PRINT(" %s", GET_IP6ADDR_STRING(add_addr->u.v6.addr));
 382                 if (opt_len == 22 || opt_len == 30)
 383                         ND_PRINT(":%u", GET_BE_U_2(add_addr->u.v6.port));
 384                 if (opt_len == 28)
 385                         ND_PRINT(" hmac 0x%" PRIx64, GET_BE_U_8(add_addr->u.v6np.mac));
 386                 if (opt_len == 30)
 387                         ND_PRINT(" hmac 0x%" PRIx64, GET_BE_U_8(add_addr->u.v6.mac));
 388         }
 389
 390         return 1;
 391 }
 392
 393 static int
 394 remove_addr_print(netdissect_options *ndo,
 395                   const u_char *opt, u_int opt_len, u_char flags _U_)
 396 {
 397         const struct mp_remove_addr *remove_addr = (const struct mp_remove_addr *) opt;
 398         u_int i;
 399
 400         if (opt_len < 4)
 401                 return 0;
 402
 403         opt_len -= 3;
 404         ND_PRINT(" id");
 405         for (i = 0; i < opt_len; i++)
 406                 ND_PRINT(" %u", GET_U_1(remove_addr->addrs_id[i]));
 407         return 1;
 408 }
 409
 410 static int
 411 mp_prio_print(netdissect_options *ndo,
 412               const u_char *opt, u_int opt_len, u_char flags _U_)
 413 {
 414         const struct mp_prio *mpp = (const struct mp_prio *) opt;
 415
 416         if (opt_len != 3 && opt_len != 4)
 417                 return 0;
 418
 419         if (GET_U_1(mpp->sub_b) & MP_PRIO_B)
 420                 ND_PRINT(" backup");
 421         else
 422                 ND_PRINT(" non-backup");
 423         if (opt_len == 4)
 424                 ND_PRINT(" id %u", GET_U_1(mpp->addr_id));
 425
 426         return 1;
 427 }
 428
 429 static int
 430 mp_fail_print(netdissect_options *ndo,
 431               const u_char *opt, u_int opt_len, u_char flags _U_)
 432 {
 433         if (opt_len != 12)
 434                 return 0;
 435
 436         ND_PRINT(" seq %" PRIu64, GET_BE_U_8(opt + 4));
 437         return 1;
 438 }
 439
 440 static int
 441 mp_fast_close_print(netdissect_options *ndo,
 442                     const u_char *opt, u_int opt_len, u_char flags _U_)
 443 {
 444         if (opt_len != 12)
 445                 return 0;
 446
 447         ND_PRINT(" key 0x%" PRIx64, GET_BE_U_8(opt + 4));
 448         return 1;
 449 }
 450
 451 static const struct {
 452         const char *name;
 453         int (*print)(netdissect_options *, const u_char *, u_int, u_char);
 454 } mptcp_options[] = {
 455         { "capable",    mp_capable_print },
 456         { "join",       mp_join_print },
 457         { "dss",        mp_dss_print },
 458         { "add-addr",   add_addr_print },
 459         { "rem-addr",   remove_addr_print },
 460         { "prio",       mp_prio_print },
 461         { "fail",       mp_fail_print },
 462         { "fast-close", mp_fast_close_print },
 463         { "unknown",    dummy_print },
 464 };
 465
 466 int
 467 mptcp_print(netdissect_options *ndo,
 468             const u_char *cp, u_int len, u_char flags)
 469 {
 470         const struct mptcp_option *opt;
 471         u_int subtype;
 472
 473         ndo->ndo_protocol = "mptcp";
 474         if (len < 3)
 475                 return 0;
 476
 477         opt = (const struct mptcp_option *) cp;
 478         subtype = MPTCP_OPT_SUBTYPE(GET_U_1(opt->sub_etc));
 479         subtype = ND_MIN(subtype, MPTCP_SUB_FCLOSE + 1);
 480
 481         ND_PRINT(" %s", mptcp_options[subtype].name);
 482         return mptcp_options[subtype].print(ndo, cp, len, flags);
 483 }