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         uint8_t        kind;
  62         uint8_t        len;
  63         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         uint8_t        kind;
  70         uint8_t        len;
  71         uint8_t        sub_ver;
  72         uint8_t        flags;
  73         uint8_t        sender_key[8];
  74         uint8_t        receiver_key[8];
  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         uint8_t        kind;
  83         uint8_t        len;
  84         uint8_t        sub_b;
  85         uint8_t        addr_id;
  86         union {
  87                 struct {
  88                         uint8_t         token[4];
  89                         uint8_t         nonce[4];
  90                 } syn;
  91                 struct {
  92                         uint8_t         mac[8];
  93                         uint8_t         nonce[4];
  94                 } synack;
  95                 struct {
  96                         uint8_t        mac[20];
  97                 } ack;
  98         } u;
  99 };
 100
 101 #define MP_JOIN_B                       0x01
 102
 103 struct mp_dss {
 104         uint8_t        kind;
 105         uint8_t        len;
 106         uint8_t        sub;
 107         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         uint8_t        kind;
 118         uint8_t        len;
 119         uint8_t        sub_ipver;
 120         uint8_t        addr_id;
 121         union {
 122                 struct {
 123                         uint8_t         addr[4];
 124                         uint8_t         port[2];
 125                 } v4;
 126                 struct {
 127                         uint8_t         addr[16];
 128                         uint8_t         port[2];
 129                 } v6;
 130         } u;
 131 };
 132
 133 #define MP_ADD_ADDR_IPVER(sub_ipver)    (((sub_ipver) >> 0) & 0xF)
 134
 135 struct mp_remove_addr {
 136         uint8_t        kind;
 137         uint8_t        len;
 138         uint8_t        sub;
 139         /* list of addr_id */
 140         uint8_t        addrs_id;
 141 };
 142
 143 struct mp_fail {
 144         uint8_t        kind;
 145         uint8_t        len;
 146         uint8_t        sub;
 147         uint8_t        resv;
 148         uint8_t        data_seq[8];
 149 };
 150
 151 struct mp_close {
 152         uint8_t        kind;
 153         uint8_t        len;
 154         uint8_t        sub;
 155         uint8_t        rsv;
 156         uint8_t        key[8];
 157 };
 158
 159 struct mp_prio {
 160         uint8_t        kind;
 161         uint8_t        len;
 162         uint8_t        sub_b;
 163         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((ndo, " Unknown Version (%d)", MP_CAPABLE_OPT_VERSION(mpc->sub_ver)));
 187                 return 1;
 188         }
 189
 190         if (mpc->flags & MP_CAPABLE_C)
 191                 ND_PRINT((ndo, " csum"));
 192         ND_PRINT((ndo, " {0x%" PRIx64, EXTRACT_64BITS(mpc->sender_key)));
 193         if (opt_len == 20) /* ACK */
 194                 ND_PRINT((ndo, ",0x%" PRIx64, EXTRACT_64BITS(mpc->receiver_key)));
 195         ND_PRINT((ndo, "}"));
 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 (mpj->sub_b & MP_JOIN_B)
 212                         ND_PRINT((ndo, " backup"));
 213                 ND_PRINT((ndo, " id %u", mpj->addr_id));
 214         }
 215
 216         switch (opt_len) {
 217         case 12: /* SYN */
 218                 ND_PRINT((ndo, " token 0x%x" " nonce 0x%x",
 219                         EXTRACT_32BITS(mpj->u.syn.token),
 220                         EXTRACT_32BITS(mpj->u.syn.nonce)));
 221                 break;
 222         case 16: /* SYN/ACK */
 223                 ND_PRINT((ndo, " hmac 0x%" PRIx64 " nonce 0x%x",
 224                         EXTRACT_64BITS(mpj->u.synack.mac),
 225                         EXTRACT_32BITS(mpj->u.synack.nonce)));
 226                 break;
 227         case 24: {/* ACK */
 228                 size_t i;
 229                 ND_PRINT((ndo, " hmac 0x"));
 230                 for (i = 0; i < sizeof(mpj->u.ack.mac); ++i)
 231                         ND_PRINT((ndo, "%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
 245         /* We need the flags, at a minimum. */
 246         if (opt_len < 4)
 247                 return 0;
 248
 249         if (flags & TH_SYN)
 250                 return 0;
 251
 252         if (mdss->flags & MP_DSS_F)
 253                 ND_PRINT((ndo, " fin"));
 254
 255         opt += 4;
 256         opt_len -= 4;
 257         if (mdss->flags & MP_DSS_A) {
 258                 /* Ack present */
 259                 ND_PRINT((ndo, " ack "));
 260                 /*
 261                  * If the a flag is set, we have an 8-byte ack; if it's
 262                  * clear, we have a 4-byte ack.
 263                  */
 264                 if (mdss->flags & MP_DSS_a) {
 265                         if (opt_len < 8)
 266                                 return 0;
 267                         ND_PRINT((ndo, "%" PRIu64, EXTRACT_64BITS(opt)));
 268                         opt += 8;
 269                         opt_len -= 8;
 270                 } else {
 271                         if (opt_len < 4)
 272                                 return 0;
 273                         ND_PRINT((ndo, "%u", EXTRACT_32BITS(opt)));
 274                         opt += 4;
 275                         opt_len -= 4;
 276                 }
 277         }
 278
 279         if (mdss->flags & MP_DSS_M) {
 280                 /*
 281                  * Data Sequence Number (DSN), Subflow Sequence Number (SSN),
 282                  * Data-Level Length present, and Checksum possibly present.
 283                  */
 284                 ND_PRINT((ndo, " seq "));
 285                 /*
 286                  * If the m flag is set, we have an 8-byte NDS; if it's clear,
 287                  * we have a 4-byte DSN.
 288                  */
 289                 if (mdss->flags & MP_DSS_m) {
 290                         if (opt_len < 8)
 291                                 return 0;
 292                         ND_PRINT((ndo, "%" PRIu64, EXTRACT_64BITS(opt)));
 293                         opt += 8;
 294                         opt_len -= 8;
 295                 } else {
 296                         if (opt_len < 4)
 297                                 return 0;
 298                         ND_PRINT((ndo, "%u", EXTRACT_32BITS(opt)));
 299                         opt += 4;
 300                         opt_len -= 4;
 301                 }
 302                 if (opt_len < 4)
 303                         return 0;
 304                 ND_PRINT((ndo, " subseq %u", EXTRACT_32BITS(opt)));
 305                 opt += 4;
 306                 opt_len -= 4;
 307                 if (opt_len < 2)
 308                         return 0;
 309                 ND_PRINT((ndo, " len %u", EXTRACT_16BITS(opt)));
 310                 opt += 2;
 311                 opt_len -= 2;
 312
 313                 /*
 314                  * The Checksum is present only if negotiated.
 315                  * If there are at least 2 bytes left, process the next 2
 316                  * bytes as the Checksum.
 317                  */
 318                 if (opt_len >= 2) {
 319                         ND_PRINT((ndo, " csum 0x%x", EXTRACT_16BITS(opt)));
 320                         opt_len -= 2;
 321                 }
 322         }
 323         if (opt_len != 0)
 324                 return 0;
 325         return 1;
 326 }
 327
 328 static int
 329 add_addr_print(netdissect_options *ndo,
 330                const u_char *opt, u_int opt_len, u_char flags _U_)
 331 {
 332         const struct mp_add_addr *add_addr = (const struct mp_add_addr *) opt;
 333         u_int ipver = MP_ADD_ADDR_IPVER(add_addr->sub_ipver);
 334
 335         if (!((opt_len == 8 || opt_len == 10) && ipver == 4) &&
 336             !((opt_len == 20 || opt_len == 22) && ipver == 6))
 337                 return 0;
 338
 339         ND_PRINT((ndo, " id %u", add_addr->addr_id));
 340         switch (ipver) {
 341         case 4:
 342                 ND_PRINT((ndo, " %s", ipaddr_string(ndo, add_addr->u.v4.addr)));
 343                 if (opt_len == 10)
 344                         ND_PRINT((ndo, ":%u", EXTRACT_16BITS(add_addr->u.v4.port)));
 345                 break;
 346         case 6:
 347                 ND_PRINT((ndo, " %s", ip6addr_string(ndo, add_addr->u.v6.addr)));
 348                 if (opt_len == 22)
 349                         ND_PRINT((ndo, ":%u", EXTRACT_16BITS(add_addr->u.v6.port)));
 350                 break;
 351         default:
 352                 return 0;
 353         }
 354
 355         return 1;
 356 }
 357
 358 static int
 359 remove_addr_print(netdissect_options *ndo,
 360                   const u_char *opt, u_int opt_len, u_char flags _U_)
 361 {
 362         const struct mp_remove_addr *remove_addr = (const struct mp_remove_addr *) opt;
 363         const uint8_t *addr_id = &remove_addr->addrs_id;
 364
 365         if (opt_len < 4)
 366                 return 0;
 367
 368         opt_len -= 3;
 369         ND_PRINT((ndo, " id"));
 370         while (opt_len--)
 371                 ND_PRINT((ndo, " %u", *addr_id++));
 372         return 1;
 373 }
 374
 375 static int
 376 mp_prio_print(netdissect_options *ndo,
 377               const u_char *opt, u_int opt_len, u_char flags _U_)
 378 {
 379         const struct mp_prio *mpp = (const struct mp_prio *) opt;
 380
 381         if (opt_len != 3 && opt_len != 4)
 382                 return 0;
 383
 384         if (mpp->sub_b & MP_PRIO_B)
 385                 ND_PRINT((ndo, " backup"));
 386         else
 387                 ND_PRINT((ndo, " non-backup"));
 388         if (opt_len == 4)
 389                 ND_PRINT((ndo, " id %u", mpp->addr_id));
 390
 391         return 1;
 392 }
 393
 394 static int
 395 mp_fail_print(netdissect_options *ndo,
 396               const u_char *opt, u_int opt_len, u_char flags _U_)
 397 {
 398         if (opt_len != 12)
 399                 return 0;
 400
 401         ND_PRINT((ndo, " seq %" PRIu64, EXTRACT_64BITS(opt + 4)));
 402         return 1;
 403 }
 404
 405 static int
 406 mp_fast_close_print(netdissect_options *ndo,
 407                     const u_char *opt, u_int opt_len, u_char flags _U_)
 408 {
 409         if (opt_len != 12)
 410                 return 0;
 411
 412         ND_PRINT((ndo, " key 0x%" PRIx64, EXTRACT_64BITS(opt + 4)));
 413         return 1;
 414 }
 415
 416 static const struct {
 417         const char *name;
 418         int (*print)(netdissect_options *, const u_char *, u_int, u_char);
 419 } mptcp_options[] = {
 420         { "capable", mp_capable_print},
 421         { "join",       mp_join_print },
 422         { "dss",        mp_dss_print },
 423         { "add-addr",   add_addr_print },
 424         { "rem-addr",   remove_addr_print },
 425         { "prio",       mp_prio_print },
 426         { "fail",       mp_fail_print },
 427         { "fast-close", mp_fast_close_print },
 428         { "unknown",    dummy_print },
 429 };
 430
 431 int
 432 mptcp_print(netdissect_options *ndo,
 433             const u_char *cp, u_int len, u_char flags)
 434 {
 435         const struct mptcp_option *opt;
 436         u_int subtype;
 437
 438         if (len < 3)
 439                 return 0;
 440
 441         opt = (const struct mptcp_option *) cp;
 442         subtype = min(MPTCP_OPT_SUBTYPE(opt->sub_etc), MPTCP_SUB_FCLOSE + 1);
 443
 444         ND_PRINT((ndo, " %s", mptcp_options[subtype].name));
 445         return mptcp_options[subtype].print(ndo, cp, len, flags);
 446 }