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 u_int mp_dss_len(const  struct mp_dss *m, int csum)
 240 {
 241         u_int len;
 242
 243         len = 4;
 244         if (m->flags & MP_DSS_A) {
 245                 /* Ack present - 4 or 8 octets */
 246                 len += (m->flags & MP_DSS_a) ? 8 : 4;
 247         }
 248         if (m->flags & MP_DSS_M) {
 249                 /*
 250                  * Data Sequence Number (DSN), Subflow Sequence Number (SSN),
 251                  * Data-Level Length present, and Checksum possibly present.
 252                  * All but the Checksum are 10 bytes if the m flag is
 253                  * clear (4-byte DSN) and 14 bytes if the m flag is set
 254                  * (8-byte DSN).
 255                  */
 256                 len += (m->flags & MP_DSS_m) ? 14 : 10;
 257
 258                 /*
 259                  * The Checksum is present only if negotiated.
 260                  */
 261                 if (csum)
 262                         len += 2;
 263         }
 264         return len;
 265 }
 266
 267 static int
 268 mp_dss_print(netdissect_options *ndo,
 269              const u_char *opt, u_int opt_len, u_char flags)
 270 {
 271         const struct mp_dss *mdss = (const struct mp_dss *) opt;
 272
 273         if ((opt_len != mp_dss_len(mdss, 1) &&
 274              opt_len != mp_dss_len(mdss, 0)) || flags & TH_SYN)
 275                 return 0;
 276
 277         if (mdss->flags & MP_DSS_F)
 278                 ND_PRINT((ndo, " fin"));
 279
 280         opt += 4;
 281         if (mdss->flags & MP_DSS_A) {
 282                 ND_PRINT((ndo, " ack "));
 283                 if (mdss->flags & MP_DSS_a) {
 284                         ND_PRINT((ndo, "%" PRIu64, EXTRACT_64BITS(opt)));
 285                         opt += 8;
 286                 } else {
 287                         ND_PRINT((ndo, "%u", EXTRACT_32BITS(opt)));
 288                         opt += 4;
 289                 }
 290         }
 291
 292         if (mdss->flags & MP_DSS_M) {
 293                 ND_PRINT((ndo, " seq "));
 294                 if (mdss->flags & MP_DSS_m) {
 295                         ND_PRINT((ndo, "%" PRIu64, EXTRACT_64BITS(opt)));
 296                         opt += 8;
 297                 } else {
 298                         ND_PRINT((ndo, "%u", EXTRACT_32BITS(opt)));
 299                         opt += 4;
 300                 }
 301                 ND_PRINT((ndo, " subseq %u", EXTRACT_32BITS(opt)));
 302                 opt += 4;
 303                 ND_PRINT((ndo, " len %u", EXTRACT_16BITS(opt)));
 304                 opt += 2;
 305
 306                 if (opt_len == mp_dss_len(mdss, 1))
 307                         ND_PRINT((ndo, " csum 0x%x", EXTRACT_16BITS(opt)));
 308         }
 309         return 1;
 310 }
 311
 312 static int
 313 add_addr_print(netdissect_options *ndo,
 314                const u_char *opt, u_int opt_len, u_char flags _U_)
 315 {
 316         const struct mp_add_addr *add_addr = (const struct mp_add_addr *) opt;
 317         u_int ipver = MP_ADD_ADDR_IPVER(add_addr->sub_ipver);
 318
 319         if (!((opt_len == 8 || opt_len == 10) && ipver == 4) &&
 320             !((opt_len == 20 || opt_len == 22) && ipver == 6))
 321                 return 0;
 322
 323         ND_PRINT((ndo, " id %u", add_addr->addr_id));
 324         switch (ipver) {
 325         case 4:
 326                 ND_PRINT((ndo, " %s", ipaddr_string(ndo, add_addr->u.v4.addr)));
 327                 if (opt_len == 10)
 328                         ND_PRINT((ndo, ":%u", EXTRACT_16BITS(add_addr->u.v4.port)));
 329                 break;
 330         case 6:
 331                 ND_PRINT((ndo, " %s", ip6addr_string(ndo, add_addr->u.v6.addr)));
 332                 if (opt_len == 22)
 333                         ND_PRINT((ndo, ":%u", EXTRACT_16BITS(add_addr->u.v6.port)));
 334                 break;
 335         default:
 336                 return 0;
 337         }
 338
 339         return 1;
 340 }
 341
 342 static int
 343 remove_addr_print(netdissect_options *ndo,
 344                   const u_char *opt, u_int opt_len, u_char flags _U_)
 345 {
 346         const struct mp_remove_addr *remove_addr = (const struct mp_remove_addr *) opt;
 347         const uint8_t *addr_id = &remove_addr->addrs_id;
 348
 349         if (opt_len < 4)
 350                 return 0;
 351
 352         opt_len -= 3;
 353         ND_PRINT((ndo, " id"));
 354         while (opt_len--)
 355                 ND_PRINT((ndo, " %u", *addr_id++));
 356         return 1;
 357 }
 358
 359 static int
 360 mp_prio_print(netdissect_options *ndo,
 361               const u_char *opt, u_int opt_len, u_char flags _U_)
 362 {
 363         const struct mp_prio *mpp = (const struct mp_prio *) opt;
 364
 365         if (opt_len != 3 && opt_len != 4)
 366                 return 0;
 367
 368         if (mpp->sub_b & MP_PRIO_B)
 369                 ND_PRINT((ndo, " backup"));
 370         else
 371                 ND_PRINT((ndo, " non-backup"));
 372         if (opt_len == 4)
 373                 ND_PRINT((ndo, " id %u", mpp->addr_id));
 374
 375         return 1;
 376 }
 377
 378 static int
 379 mp_fail_print(netdissect_options *ndo,
 380               const u_char *opt, u_int opt_len, u_char flags _U_)
 381 {
 382         if (opt_len != 12)
 383                 return 0;
 384
 385         ND_PRINT((ndo, " seq %" PRIu64, EXTRACT_64BITS(opt + 4)));
 386         return 1;
 387 }
 388
 389 static int
 390 mp_fast_close_print(netdissect_options *ndo,
 391                     const u_char *opt, u_int opt_len, u_char flags _U_)
 392 {
 393         if (opt_len != 12)
 394                 return 0;
 395
 396         ND_PRINT((ndo, " key 0x%" PRIx64, EXTRACT_64BITS(opt + 4)));
 397         return 1;
 398 }
 399
 400 static const struct {
 401         const char *name;
 402         int (*print)(netdissect_options *, const u_char *, u_int, u_char);
 403 } mptcp_options[] = {
 404         { "capable", mp_capable_print},
 405         { "join",       mp_join_print },
 406         { "dss",        mp_dss_print },
 407         { "add-addr",   add_addr_print },
 408         { "rem-addr",   remove_addr_print },
 409         { "prio",       mp_prio_print },
 410         { "fail",       mp_fail_print },
 411         { "fast-close", mp_fast_close_print },
 412         { "unknown",    dummy_print },
 413 };
 414
 415 int
 416 mptcp_print(netdissect_options *ndo,
 417             const u_char *cp, u_int len, u_char flags)
 418 {
 419         const struct mptcp_option *opt;
 420         u_int subtype;
 421
 422         if (len < 3)
 423                 return 0;
 424
 425         opt = (const struct mptcp_option *) cp;
 426         subtype = min(MPTCP_OPT_SUBTYPE(opt->sub_etc), MPTCP_SUB_FCLOSE + 1);
 427
 428         ND_PRINT((ndo, " %s", mptcp_options[subtype].name));
 429         return mptcp_options[subtype].print(ndo, cp, len, flags);
 430 }