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)      ((EXTRACT_U_1(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) ((EXTRACT_U_1(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 struct mp_add_addr {
 117         nd_uint8_t     kind;
 118         nd_uint8_t     len;
 119         nd_uint8_t     sub_ipver;
 120         nd_uint8_t     addr_id;
 121         union {
 122                 struct {
 123                         nd_ipv4         addr;
 124                         nd_uint16_t     port;
 125                 } v4;
 126                 struct {
 127                         nd_ipv6         addr;
 128                         nd_uint16_t     port;
 129                 } v6;
 130         } u;
 131 };
 132
 133 #define MP_ADD_ADDR_IPVER(sub_ipver)    ((EXTRACT_U_1(sub_ipver) >> 0) & 0xF)
 134
 135 struct mp_remove_addr {
 136         nd_uint8_t     kind;
 137         nd_uint8_t     len;
 138         nd_uint8_t     sub;
 139         /* list of addr_id */
 140         nd_uint8_t     addrs_id[1];
 141 };
 142
 143 struct mp_fail {
 144         nd_uint8_t     kind;
 145         nd_uint8_t     len;
 146         nd_uint8_t     sub;
 147         nd_uint8_t     resv;
 148         nd_uint64_t    data_seq;
 149 };
 150
 151 struct mp_close {
 152         nd_uint8_t     kind;
 153         nd_uint8_t     len;
 154         nd_uint8_t     sub;
 155         nd_uint8_t     rsv;
 156         nd_byte        key[8];
 157 };
 158
 159 struct mp_prio {
 160         nd_uint8_t     kind;
 161         nd_uint8_t     len;
 162         nd_uint8_t     sub_b;
 163         nd_uint8_t     addr_id;
 164 };
 165
 166 #define MP_PRIO_B                       0x01
 167
 168 static int
 169 dummy_print(netdissect_options *ndo _U_,
 170             const u_char *opt _U_, u_int opt_len _U_, u_char flags _U_)
 171 {
 172         return 1;
 173 }
 174
 175 static int
 176 mp_capable_print(netdissect_options *ndo,
 177                  const u_char *opt, u_int opt_len, u_char flags)
 178 {
 179         const struct mp_capable *mpc = (const struct mp_capable *) opt;
 180
 181         if (!(opt_len == 12 && (flags & TH_SYN)) &&
 182             !(opt_len == 20 && (flags & (TH_SYN | TH_ACK)) == TH_ACK))
 183                 return 0;
 184
 185         if (MP_CAPABLE_OPT_VERSION(mpc->sub_ver) != 0) {
 186                 ND_PRINT(" Unknown Version (%u)", MP_CAPABLE_OPT_VERSION(mpc->sub_ver));
 187                 return 1;
 188         }
 189
 190         if (EXTRACT_U_1(mpc->flags) & MP_CAPABLE_C)
 191                 ND_PRINT(" csum");
 192         ND_PRINT(" {0x%" PRIx64, EXTRACT_BE_U_8(mpc->sender_key));
 193         if (opt_len == 20) /* ACK */
 194                 ND_PRINT(",0x%" PRIx64, EXTRACT_BE_U_8(mpc->receiver_key));
 195         ND_PRINT("}");
 196         return 1;
 197 }
 198
 199 static int
 200 mp_join_print(netdissect_options *ndo,
 201               const u_char *opt, u_int opt_len, u_char flags)
 202 {
 203         const struct mp_join *mpj = (const struct mp_join *) opt;
 204
 205         if (!(opt_len == 12 && (flags & TH_SYN)) &&
 206             !(opt_len == 16 && (flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) &&
 207             !(opt_len == 24 && (flags & TH_ACK)))
 208                 return 0;
 209
 210         if (opt_len != 24) {
 211                 if (EXTRACT_U_1(mpj->sub_b) & MP_JOIN_B)
 212                         ND_PRINT(" backup");
 213                 ND_PRINT(" id %u", EXTRACT_U_1(mpj->addr_id));
 214         }
 215
 216         switch (opt_len) {
 217         case 12: /* SYN */
 218                 ND_PRINT(" token 0x%x" " nonce 0x%x",
 219                         EXTRACT_BE_U_4(mpj->u.syn.token),
 220                         EXTRACT_BE_U_4(mpj->u.syn.nonce));
 221                 break;
 222         case 16: /* SYN/ACK */
 223                 ND_PRINT(" hmac 0x%" PRIx64 " nonce 0x%x",
 224                         EXTRACT_BE_U_8(mpj->u.synack.mac),
 225                         EXTRACT_BE_U_4(mpj->u.synack.nonce));
 226                 break;
 227         case 24: {/* ACK */
 228                 size_t i;
 229                 ND_PRINT(" hmac 0x");
 230                 for (i = 0; i < sizeof(mpj->u.ack.mac); ++i)
 231                         ND_PRINT("%02x", mpj->u.ack.mac[i]);
 232         }
 233         default:
 234                 break;
 235         }
 236         return 1;
 237 }
 238
 239 static int
 240 mp_dss_print(netdissect_options *ndo,
 241              const u_char *opt, u_int opt_len, u_char flags)
 242 {
 243         const struct mp_dss *mdss = (const struct mp_dss *) opt;
 244         uint8_t mdss_flags;
 245
 246         /* We need the flags, at a minimum. */
 247         if (opt_len < 4)
 248                 return 0;
 249
 250         if (flags & TH_SYN)
 251                 return 0;
 252
 253         mdss_flags = EXTRACT_U_1(mdss->flags);
 254         if (mdss_flags & MP_DSS_F)
 255                 ND_PRINT(" fin");
 256
 257         opt += 4;
 258         opt_len -= 4;
 259         if (mdss_flags & MP_DSS_A) {
 260                 /* Ack present */
 261                 ND_PRINT(" ack ");
 262                 /*
 263                  * If the a flag is set, we have an 8-byte ack; if it's
 264                  * clear, we have a 4-byte ack.
 265                  */
 266                 if (mdss_flags & MP_DSS_a) {
 267                         if (opt_len < 8)
 268                                 return 0;
 269                         ND_PRINT("%" PRIu64, EXTRACT_BE_U_8(opt));
 270                         opt += 8;
 271                         opt_len -= 8;
 272                 } else {
 273                         if (opt_len < 4)
 274                                 return 0;
 275                         ND_PRINT("%u", EXTRACT_BE_U_4(opt));
 276                         opt += 4;
 277                         opt_len -= 4;
 278                 }
 279         }
 280
 281         if (mdss_flags & MP_DSS_M) {
 282                 /*
 283                  * Data Sequence Number (DSN), Subflow Sequence Number (SSN),
 284                  * Data-Level Length present, and Checksum possibly present.
 285                  */
 286                 ND_PRINT(" seq ");
 287                 /*
 288                  * If the m flag is set, we have an 8-byte NDS; if it's clear,
 289                  * we have a 4-byte DSN.
 290                  */
 291                 if (mdss_flags & MP_DSS_m) {
 292                         if (opt_len < 8)
 293                                 return 0;
 294                         ND_PRINT("%" PRIu64, EXTRACT_BE_U_8(opt));
 295                         opt += 8;
 296                         opt_len -= 8;
 297                 } else {
 298                         if (opt_len < 4)
 299                                 return 0;
 300                         ND_PRINT("%u", EXTRACT_BE_U_4(opt));
 301                         opt += 4;
 302                         opt_len -= 4;
 303                 }
 304                 if (opt_len < 4)
 305                         return 0;
 306                 ND_PRINT(" subseq %u", EXTRACT_BE_U_4(opt));
 307                 opt += 4;
 308                 opt_len -= 4;
 309                 if (opt_len < 2)
 310                         return 0;
 311                 ND_PRINT(" len %u", EXTRACT_BE_U_2(opt));
 312                 opt += 2;
 313                 opt_len -= 2;
 314
 315                 /*
 316                  * The Checksum is present only if negotiated.
 317                  * If there are at least 2 bytes left, process the next 2
 318                  * bytes as the Checksum.
 319                  */
 320                 if (opt_len >= 2) {
 321                         ND_PRINT(" csum 0x%x", EXTRACT_BE_U_2(opt));
 322                         opt_len -= 2;
 323                 }
 324         }
 325         if (opt_len != 0)
 326                 return 0;
 327         return 1;
 328 }
 329
 330 static int
 331 add_addr_print(netdissect_options *ndo,
 332                const u_char *opt, u_int opt_len, u_char flags _U_)
 333 {
 334         const struct mp_add_addr *add_addr = (const struct mp_add_addr *) opt;
 335         u_int ipver = MP_ADD_ADDR_IPVER(add_addr->sub_ipver);
 336
 337         if (!((opt_len == 8 || opt_len == 10) && ipver == 4) &&
 338             !((opt_len == 20 || opt_len == 22) && ipver == 6))
 339                 return 0;
 340
 341         ND_PRINT(" id %u", EXTRACT_U_1(add_addr->addr_id));
 342         switch (ipver) {
 343         case 4:
 344                 ND_PRINT(" %s", ipaddr_string(ndo, add_addr->u.v4.addr));
 345                 if (opt_len == 10)
 346                         ND_PRINT(":%u", EXTRACT_BE_U_2(add_addr->u.v4.port));
 347                 break;
 348         case 6:
 349                 ND_PRINT(" %s", ip6addr_string(ndo, add_addr->u.v6.addr));
 350                 if (opt_len == 22)
 351                         ND_PRINT(":%u", EXTRACT_BE_U_2(add_addr->u.v6.port));
 352                 break;
 353         default:
 354                 return 0;
 355         }
 356
 357         return 1;
 358 }
 359
 360 static int
 361 remove_addr_print(netdissect_options *ndo,
 362                   const u_char *opt, u_int opt_len, u_char flags _U_)
 363 {
 364         const struct mp_remove_addr *remove_addr = (const struct mp_remove_addr *) opt;
 365         u_int i;
 366
 367         if (opt_len < 4)
 368                 return 0;
 369
 370         opt_len -= 3;
 371         ND_PRINT(" id");
 372         for (i = 0; i < opt_len; i++)
 373                 ND_PRINT(" %u", EXTRACT_U_1(remove_addr->addrs_id[i]));
 374         return 1;
 375 }
 376
 377 static int
 378 mp_prio_print(netdissect_options *ndo,
 379               const u_char *opt, u_int opt_len, u_char flags _U_)
 380 {
 381         const struct mp_prio *mpp = (const struct mp_prio *) opt;
 382
 383         if (opt_len != 3 && opt_len != 4)
 384                 return 0;
 385
 386         if (EXTRACT_U_1(mpp->sub_b) & MP_PRIO_B)
 387                 ND_PRINT(" backup");
 388         else
 389                 ND_PRINT(" non-backup");
 390         if (opt_len == 4)
 391                 ND_PRINT(" id %u", EXTRACT_U_1(mpp->addr_id));
 392
 393         return 1;
 394 }
 395
 396 static int
 397 mp_fail_print(netdissect_options *ndo,
 398               const u_char *opt, u_int opt_len, u_char flags _U_)
 399 {
 400         if (opt_len != 12)
 401                 return 0;
 402
 403         ND_PRINT(" seq %" PRIu64, EXTRACT_BE_U_8(opt + 4));
 404         return 1;
 405 }
 406
 407 static int
 408 mp_fast_close_print(netdissect_options *ndo,
 409                     const u_char *opt, u_int opt_len, u_char flags _U_)
 410 {
 411         if (opt_len != 12)
 412                 return 0;
 413
 414         ND_PRINT(" key 0x%" PRIx64, EXTRACT_BE_U_8(opt + 4));
 415         return 1;
 416 }
 417
 418 static const struct {
 419         const char *name;
 420         int (*print)(netdissect_options *, const u_char *, u_int, u_char);
 421 } mptcp_options[] = {
 422         { "capable", mp_capable_print},
 423         { "join",       mp_join_print },
 424         { "dss",        mp_dss_print },
 425         { "add-addr",   add_addr_print },
 426         { "rem-addr",   remove_addr_print },
 427         { "prio",       mp_prio_print },
 428         { "fail",       mp_fail_print },
 429         { "fast-close", mp_fast_close_print },
 430         { "unknown",    dummy_print },
 431 };
 432
 433 int
 434 mptcp_print(netdissect_options *ndo,
 435             const u_char *cp, u_int len, u_char flags)
 436 {
 437         const struct mptcp_option *opt;
 438         u_int subtype;
 439
 440         if (len < 3)
 441                 return 0;
 442
 443         opt = (const struct mptcp_option *) cp;
 444         subtype = min(MPTCP_OPT_SUBTYPE(opt->sub_etc), MPTCP_SUB_FCLOSE + 1);
 445
 446         ND_PRINT(" %s", mptcp_options[subtype].name);
 447         return mptcp_options[subtype].print(ndo, cp, len, flags);
 448 }