net/sched/em_meta.c

   1 /*
   2  * net/sched/em_meta.c  Metadata ematch
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Thomas Graf <tgraf@suug.ch>
  10  *
  11  * ==========================================================================
  12  *
  13  *      The metadata ematch compares two meta objects where each object
  14  *      represents either a meta value stored in the kernel or a static
  15  *      value provided by userspace. The objects are not provided by
  16  *      userspace itself but rather a definition providing the information
  17  *      to build them. Every object is of a certain type which must be
  18  *      equal to the object it is being compared to.
  19  *
  20  *      The definition of a objects conists of the type (meta type), a
  21  *      identifier (meta id) and additional type specific information.
  22  *      The meta id is either TCF_META_TYPE_VALUE for values provided by
  23  *      userspace or a index to the meta operations table consisting of
  24  *      function pointers to type specific meta data collectors returning
  25  *      the value of the requested meta value.
  26  *
  27  *               lvalue                                   rvalue
  28  *            +-----------+                           +-----------+
  29  *            | type: INT |                           | type: INT |
  30  *       def  | id: DEV   |                           | id: VALUE |
  31  *            | data:     |                           | data: 3   |
  32  *            +-----------+                           +-----------+
  33  *                  |                                       |
  34  *                  ---> meta_ops[INT][DEV](...)            |
  35  *                            |                             |
  36  *                  -----------                             |
  37  *                  V                                       V
  38  *            +-----------+                           +-----------+
  39  *            | type: INT |                           | type: INT |
  40  *       obj  | id: DEV |                             | id: VALUE |
  41  *            | data: 2   |<--data got filled out     | data: 3   |
  42  *            +-----------+                           +-----------+
  43  *                  |                                         |
  44  *                  --------------> 2  equals 3 <--------------
  45  *
  46  *      This is a simplified schema, the complexity varies depending
  47  *      on the meta type. Obviously, the length of the data must also
  48  *      be provided for non-numeric types.
  49  *
  50  *      Additionally, type dependent modifiers such as shift operators
  51  *      or mask may be applied to extend the functionaliy. As of now,
  52  *      the variable length type supports shifting the byte string to
  53  *      the right, eating up any number of octets and thus supporting
  54  *      wildcard interface name comparisons such as "ppp%" matching
  55  *      ppp0..9.
  56  *
  57  *      NOTE: Certain meta values depend on other subsystems and are
  58  *            only available if that subsystem is enabled in the kernel.
  59  */
  60
  61 #include <linux/slab.h>
  62 #include <linux/module.h>
  63 #include <linux/types.h>
  64 #include <linux/kernel.h>
  65 #include <linux/sched.h>
  66 #include <linux/string.h>
  67 #include <linux/skbuff.h>
  68 #include <linux/random.h>
  69 #include <linux/if_vlan.h>
  70 #include <linux/tc_ematch/tc_em_meta.h>
  71 #include <net/dst.h>
  72 #include <net/route.h>
  73 #include <net/pkt_cls.h>
  74 #include <net/sock.h>
  75
  76 struct meta_obj {
  77         unsigned long           value;
  78         unsigned int            len;
  79 };
  80
  81 struct meta_value {
  82         struct tcf_meta_val     hdr;
  83         unsigned long           val;
  84         unsigned int            len;
  85 };
  86
  87 struct meta_match {
  88         struct meta_value       lvalue;
  89         struct meta_value       rvalue;
  90 };
  91
  92 static inline int meta_id(struct meta_value *v)
  93 {
  94         return TCF_META_ID(v->hdr.kind);
  95 }
  96
  97 static inline int meta_type(struct meta_value *v)
  98 {
  99         return TCF_META_TYPE(v->hdr.kind);
 100 }
 101
 102 #define META_COLLECTOR(FUNC) static void meta_##FUNC(struct sk_buff *skb, \
 103         struct tcf_pkt_info *info, struct meta_value *v, \
 104         struct meta_obj *dst, int *err)
 105
 106 /**************************************************************************
 107  * System status & misc
 108  **************************************************************************/
 109
 110 META_COLLECTOR(int_random)
 111 {
 112         get_random_bytes(&dst->value, sizeof(dst->value));
 113 }
 114
 115 static inline unsigned long fixed_loadavg(int load)
 116 {
 117         int rnd_load = load + (FIXED_1/200);
 118         int rnd_frac = ((rnd_load & (FIXED_1-1)) * 100) >> FSHIFT;
 119
 120         return ((rnd_load >> FSHIFT) * 100) + rnd_frac;
 121 }
 122
 123 META_COLLECTOR(int_loadavg_0)
 124 {
 125         dst->value = fixed_loadavg(avenrun[0]);
 126 }
 127
 128 META_COLLECTOR(int_loadavg_1)
 129 {
 130         dst->value = fixed_loadavg(avenrun[1]);
 131 }
 132
 133 META_COLLECTOR(int_loadavg_2)
 134 {
 135         dst->value = fixed_loadavg(avenrun[2]);
 136 }
 137
 138 /**************************************************************************
 139  * Device names & indices
 140  **************************************************************************/
 141
 142 static inline int int_dev(struct net_device *dev, struct meta_obj *dst)
 143 {
 144         if (unlikely(dev == NULL))
 145                 return -1;
 146
 147         dst->value = dev->ifindex;
 148         return 0;
 149 }
 150
 151 static inline int var_dev(struct net_device *dev, struct meta_obj *dst)
 152 {
 153         if (unlikely(dev == NULL))
 154                 return -1;
 155
 156         dst->value = (unsigned long) dev->name;
 157         dst->len = strlen(dev->name);
 158         return 0;
 159 }
 160
 161 META_COLLECTOR(int_dev)
 162 {
 163         *err = int_dev(skb->dev, dst);
 164 }
 165
 166 META_COLLECTOR(var_dev)
 167 {
 168         *err = var_dev(skb->dev, dst);
 169 }
 170
 171 /**************************************************************************
 172  * vlan tag
 173  **************************************************************************/
 174
 175 META_COLLECTOR(int_vlan_tag)
 176 {
 177         unsigned short tag;
 178
 179         tag = vlan_tx_tag_get(skb);
 180         if (!tag && __vlan_get_tag(skb, &tag))
 181                 *err = -1;
 182         else
 183                 dst->value = tag;
 184 }
 185
 186
 187
 188 /**************************************************************************
 189  * skb attributes
 190  **************************************************************************/
 191
 192 META_COLLECTOR(int_priority)
 193 {
 194         dst->value = skb->priority;
 195 }
 196
 197 META_COLLECTOR(int_protocol)
 198 {
 199         /* Let userspace take care of the byte ordering */
 200         dst->value = skb->protocol;
 201 }
 202
 203 META_COLLECTOR(int_pkttype)
 204 {
 205         dst->value = skb->pkt_type;
 206 }
 207
 208 META_COLLECTOR(int_pktlen)
 209 {
 210         dst->value = skb->len;
 211 }
 212
 213 META_COLLECTOR(int_datalen)
 214 {
 215         dst->value = skb->data_len;
 216 }
 217
 218 META_COLLECTOR(int_maclen)
 219 {
 220         dst->value = skb->mac_len;
 221 }
 222
 223 META_COLLECTOR(int_rxhash)
 224 {
 225         dst->value = skb_get_hash(skb);
 226 }
 227
 228 /**************************************************************************
 229  * Netfilter
 230  **************************************************************************/
 231
 232 META_COLLECTOR(int_mark)
 233 {
 234         dst->value = skb->mark;
 235 }
 236
 237 /**************************************************************************
 238  * Traffic Control
 239  **************************************************************************/
 240
 241 META_COLLECTOR(int_tcindex)
 242 {
 243         dst->value = skb->tc_index;
 244 }
 245
 246 /**************************************************************************
 247  * Routing
 248  **************************************************************************/
 249
 250 META_COLLECTOR(int_rtclassid)
 251 {
 252         if (unlikely(skb_dst(skb) == NULL))
 253                 *err = -1;
 254         else
 255 #ifdef CONFIG_IP_ROUTE_CLASSID
 256                 dst->value = skb_dst(skb)->tclassid;
 257 #else
 258                 dst->value = 0;
 259 #endif
 260 }
 261
 262 META_COLLECTOR(int_rtiif)
 263 {
 264         if (unlikely(skb_rtable(skb) == NULL))
 265                 *err = -1;
 266         else
 267                 dst->value = inet_iif(skb);
 268 }
 269
 270 /**************************************************************************
 271  * Socket Attributes
 272  **************************************************************************/
 273
 274 #define skip_nonlocal(skb) \
 275         (unlikely(skb->sk == NULL))
 276
 277 META_COLLECTOR(int_sk_family)
 278 {
 279         if (skip_nonlocal(skb)) {
 280                 *err = -1;
 281                 return;
 282         }
 283         dst->value = skb->sk->sk_family;
 284 }
 285
 286 META_COLLECTOR(int_sk_state)
 287 {
 288         if (skip_nonlocal(skb)) {
 289                 *err = -1;
 290                 return;
 291         }
 292         dst->value = skb->sk->sk_state;
 293 }
 294
 295 META_COLLECTOR(int_sk_reuse)
 296 {
 297         if (skip_nonlocal(skb)) {
 298                 *err = -1;
 299                 return;
 300         }
 301         dst->value = skb->sk->sk_reuse;
 302 }
 303
 304 META_COLLECTOR(int_sk_bound_if)
 305 {
 306         if (skip_nonlocal(skb)) {
 307                 *err = -1;
 308                 return;
 309         }
 310         /* No error if bound_dev_if is 0, legal userspace check */
 311         dst->value = skb->sk->sk_bound_dev_if;
 312 }
 313
 314 META_COLLECTOR(var_sk_bound_if)
 315 {
 316         if (skip_nonlocal(skb)) {
 317                 *err = -1;
 318                 return;
 319         }
 320
 321         if (skb->sk->sk_bound_dev_if == 0) {
 322                 dst->value = (unsigned long) "any";
 323                 dst->len = 3;
 324         } else {
 325                 struct net_device *dev;
 326
 327                 rcu_read_lock();
 328                 dev = dev_get_by_index_rcu(sock_net(skb->sk),
 329                                            skb->sk->sk_bound_dev_if);
 330                 *err = var_dev(dev, dst);
 331                 rcu_read_unlock();
 332         }
 333 }
 334
 335 META_COLLECTOR(int_sk_refcnt)
 336 {
 337         if (skip_nonlocal(skb)) {
 338                 *err = -1;
 339                 return;
 340         }
 341         dst->value = atomic_read(&skb->sk->sk_refcnt);
 342 }
 343
 344 META_COLLECTOR(int_sk_rcvbuf)
 345 {
 346         if (skip_nonlocal(skb)) {
 347                 *err = -1;
 348                 return;
 349         }
 350         dst->value = skb->sk->sk_rcvbuf;
 351 }
 352
 353 META_COLLECTOR(int_sk_shutdown)
 354 {
 355         if (skip_nonlocal(skb)) {
 356                 *err = -1;
 357                 return;
 358         }
 359         dst->value = skb->sk->sk_shutdown;
 360 }
 361
 362 META_COLLECTOR(int_sk_proto)
 363 {
 364         if (skip_nonlocal(skb)) {
 365                 *err = -1;
 366                 return;
 367         }
 368         dst->value = skb->sk->sk_protocol;
 369 }
 370
 371 META_COLLECTOR(int_sk_type)
 372 {
 373         if (skip_nonlocal(skb)) {
 374                 *err = -1;
 375                 return;
 376         }
 377         dst->value = skb->sk->sk_type;
 378 }
 379
 380 META_COLLECTOR(int_sk_rmem_alloc)
 381 {
 382         if (skip_nonlocal(skb)) {
 383                 *err = -1;
 384                 return;
 385         }
 386         dst->value = sk_rmem_alloc_get(skb->sk);
 387 }
 388
 389 META_COLLECTOR(int_sk_wmem_alloc)
 390 {
 391         if (skip_nonlocal(skb)) {
 392                 *err = -1;
 393                 return;
 394         }
 395         dst->value = sk_wmem_alloc_get(skb->sk);
 396 }
 397
 398 META_COLLECTOR(int_sk_omem_alloc)
 399 {
 400         if (skip_nonlocal(skb)) {
 401                 *err = -1;
 402                 return;
 403         }
 404         dst->value = atomic_read(&skb->sk->sk_omem_alloc);
 405 }
 406
 407 META_COLLECTOR(int_sk_rcv_qlen)
 408 {
 409         if (skip_nonlocal(skb)) {
 410                 *err = -1;
 411                 return;
 412         }
 413         dst->value = skb->sk->sk_receive_queue.qlen;
 414 }
 415
 416 META_COLLECTOR(int_sk_snd_qlen)
 417 {
 418         if (skip_nonlocal(skb)) {
 419                 *err = -1;
 420                 return;
 421         }
 422         dst->value = skb->sk->sk_write_queue.qlen;
 423 }
 424
 425 META_COLLECTOR(int_sk_wmem_queued)
 426 {
 427         if (skip_nonlocal(skb)) {
 428                 *err = -1;
 429                 return;
 430         }
 431         dst->value = skb->sk->sk_wmem_queued;
 432 }
 433
 434 META_COLLECTOR(int_sk_fwd_alloc)
 435 {
 436         if (skip_nonlocal(skb)) {
 437                 *err = -1;
 438                 return;
 439         }
 440         dst->value = skb->sk->sk_forward_alloc;
 441 }
 442
 443 META_COLLECTOR(int_sk_sndbuf)
 444 {
 445         if (skip_nonlocal(skb)) {
 446                 *err = -1;
 447                 return;
 448         }
 449         dst->value = skb->sk->sk_sndbuf;
 450 }
 451
 452 META_COLLECTOR(int_sk_alloc)
 453 {
 454         if (skip_nonlocal(skb)) {
 455                 *err = -1;
 456                 return;
 457         }
 458         dst->value = (__force int) skb->sk->sk_allocation;
 459 }
 460
 461 META_COLLECTOR(int_sk_hash)
 462 {
 463         if (skip_nonlocal(skb)) {
 464                 *err = -1;
 465                 return;
 466         }
 467         dst->value = skb->sk->sk_hash;
 468 }
 469
 470 META_COLLECTOR(int_sk_lingertime)
 471 {
 472         if (skip_nonlocal(skb)) {
 473                 *err = -1;
 474                 return;
 475         }
 476         dst->value = skb->sk->sk_lingertime / HZ;
 477 }
 478
 479 META_COLLECTOR(int_sk_err_qlen)
 480 {
 481         if (skip_nonlocal(skb)) {
 482                 *err = -1;
 483                 return;
 484         }
 485         dst->value = skb->sk->sk_error_queue.qlen;
 486 }
 487
 488 META_COLLECTOR(int_sk_ack_bl)
 489 {
 490         if (skip_nonlocal(skb)) {
 491                 *err = -1;
 492                 return;
 493         }
 494         dst->value = skb->sk->sk_ack_backlog;
 495 }
 496
 497 META_COLLECTOR(int_sk_max_ack_bl)
 498 {
 499         if (skip_nonlocal(skb)) {
 500                 *err = -1;
 501                 return;
 502         }
 503         dst->value = skb->sk->sk_max_ack_backlog;
 504 }
 505
 506 META_COLLECTOR(int_sk_prio)
 507 {
 508         if (skip_nonlocal(skb)) {
 509                 *err = -1;
 510                 return;
 511         }
 512         dst->value = skb->sk->sk_priority;
 513 }
 514
 515 META_COLLECTOR(int_sk_rcvlowat)
 516 {
 517         if (skip_nonlocal(skb)) {
 518                 *err = -1;
 519                 return;
 520         }
 521         dst->value = skb->sk->sk_rcvlowat;
 522 }
 523
 524 META_COLLECTOR(int_sk_rcvtimeo)
 525 {
 526         if (skip_nonlocal(skb)) {
 527                 *err = -1;
 528                 return;
 529         }
 530         dst->value = skb->sk->sk_rcvtimeo / HZ;
 531 }
 532
 533 META_COLLECTOR(int_sk_sndtimeo)
 534 {
 535         if (skip_nonlocal(skb)) {
 536                 *err = -1;
 537                 return;
 538         }
 539         dst->value = skb->sk->sk_sndtimeo / HZ;
 540 }
 541
 542 META_COLLECTOR(int_sk_sendmsg_off)
 543 {
 544         if (skip_nonlocal(skb)) {
 545                 *err = -1;
 546                 return;
 547         }
 548         dst->value = skb->sk->sk_frag.offset;
 549 }
 550
 551 META_COLLECTOR(int_sk_write_pend)
 552 {
 553         if (skip_nonlocal(skb)) {
 554                 *err = -1;
 555                 return;
 556         }
 557         dst->value = skb->sk->sk_write_pending;
 558 }
 559
 560 /**************************************************************************
 561  * Meta value collectors assignment table
 562  **************************************************************************/
 563
 564 struct meta_ops {
 565         void            (*get)(struct sk_buff *, struct tcf_pkt_info *,
 566                                struct meta_value *, struct meta_obj *, int *);
 567 };
 568
 569 #define META_ID(name) TCF_META_ID_##name
 570 #define META_FUNC(name) { .get = meta_##name }
 571
 572 /* Meta value operations table listing all meta value collectors and
 573  * assigns them to a type and meta id. */
 574 static struct meta_ops __meta_ops[TCF_META_TYPE_MAX + 1][TCF_META_ID_MAX + 1] = {
 575         [TCF_META_TYPE_VAR] = {
 576                 [META_ID(DEV)]                  = META_FUNC(var_dev),
 577                 [META_ID(SK_BOUND_IF)]          = META_FUNC(var_sk_bound_if),
 578         },
 579         [TCF_META_TYPE_INT] = {
 580                 [META_ID(RANDOM)]               = META_FUNC(int_random),
 581                 [META_ID(LOADAVG_0)]            = META_FUNC(int_loadavg_0),
 582                 [META_ID(LOADAVG_1)]            = META_FUNC(int_loadavg_1),
 583                 [META_ID(LOADAVG_2)]            = META_FUNC(int_loadavg_2),
 584                 [META_ID(DEV)]                  = META_FUNC(int_dev),
 585                 [META_ID(PRIORITY)]             = META_FUNC(int_priority),
 586                 [META_ID(PROTOCOL)]             = META_FUNC(int_protocol),
 587                 [META_ID(PKTTYPE)]              = META_FUNC(int_pkttype),
 588                 [META_ID(PKTLEN)]               = META_FUNC(int_pktlen),
 589                 [META_ID(DATALEN)]              = META_FUNC(int_datalen),
 590                 [META_ID(MACLEN)]               = META_FUNC(int_maclen),
 591                 [META_ID(NFMARK)]               = META_FUNC(int_mark),
 592                 [META_ID(TCINDEX)]              = META_FUNC(int_tcindex),
 593                 [META_ID(RTCLASSID)]            = META_FUNC(int_rtclassid),
 594                 [META_ID(RTIIF)]                = META_FUNC(int_rtiif),
 595                 [META_ID(SK_FAMILY)]            = META_FUNC(int_sk_family),
 596                 [META_ID(SK_STATE)]             = META_FUNC(int_sk_state),
 597                 [META_ID(SK_REUSE)]             = META_FUNC(int_sk_reuse),
 598                 [META_ID(SK_BOUND_IF)]          = META_FUNC(int_sk_bound_if),
 599                 [META_ID(SK_REFCNT)]            = META_FUNC(int_sk_refcnt),
 600                 [META_ID(SK_RCVBUF)]            = META_FUNC(int_sk_rcvbuf),
 601                 [META_ID(SK_SNDBUF)]            = META_FUNC(int_sk_sndbuf),
 602                 [META_ID(SK_SHUTDOWN)]          = META_FUNC(int_sk_shutdown),
 603                 [META_ID(SK_PROTO)]             = META_FUNC(int_sk_proto),
 604                 [META_ID(SK_TYPE)]              = META_FUNC(int_sk_type),
 605                 [META_ID(SK_RMEM_ALLOC)]        = META_FUNC(int_sk_rmem_alloc),
 606                 [META_ID(SK_WMEM_ALLOC)]        = META_FUNC(int_sk_wmem_alloc),
 607                 [META_ID(SK_OMEM_ALLOC)]        = META_FUNC(int_sk_omem_alloc),
 608                 [META_ID(SK_WMEM_QUEUED)]       = META_FUNC(int_sk_wmem_queued),
 609                 [META_ID(SK_RCV_QLEN)]          = META_FUNC(int_sk_rcv_qlen),
 610                 [META_ID(SK_SND_QLEN)]          = META_FUNC(int_sk_snd_qlen),
 611                 [META_ID(SK_ERR_QLEN)]          = META_FUNC(int_sk_err_qlen),
 612                 [META_ID(SK_FORWARD_ALLOCS)]    = META_FUNC(int_sk_fwd_alloc),
 613                 [META_ID(SK_ALLOCS)]            = META_FUNC(int_sk_alloc),
 614                 [META_ID(SK_HASH)]              = META_FUNC(int_sk_hash),
 615                 [META_ID(SK_LINGERTIME)]        = META_FUNC(int_sk_lingertime),
 616                 [META_ID(SK_ACK_BACKLOG)]       = META_FUNC(int_sk_ack_bl),
 617                 [META_ID(SK_MAX_ACK_BACKLOG)]   = META_FUNC(int_sk_max_ack_bl),
 618                 [META_ID(SK_PRIO)]              = META_FUNC(int_sk_prio),
 619                 [META_ID(SK_RCVLOWAT)]          = META_FUNC(int_sk_rcvlowat),
 620                 [META_ID(SK_RCVTIMEO)]          = META_FUNC(int_sk_rcvtimeo),
 621                 [META_ID(SK_SNDTIMEO)]          = META_FUNC(int_sk_sndtimeo),
 622                 [META_ID(SK_SENDMSG_OFF)]       = META_FUNC(int_sk_sendmsg_off),
 623                 [META_ID(SK_WRITE_PENDING)]     = META_FUNC(int_sk_write_pend),
 624                 [META_ID(VLAN_TAG)]             = META_FUNC(int_vlan_tag),
 625                 [META_ID(RXHASH)]               = META_FUNC(int_rxhash),
 626         }
 627 };
 628
 629 static inline struct meta_ops *meta_ops(struct meta_value *val)
 630 {
 631         return &__meta_ops[meta_type(val)][meta_id(val)];
 632 }
 633
 634 /**************************************************************************
 635  * Type specific operations for TCF_META_TYPE_VAR
 636  **************************************************************************/
 637
 638 static int meta_var_compare(struct meta_obj *a, struct meta_obj *b)
 639 {
 640         int r = a->len - b->len;
 641
 642         if (r == 0)
 643                 r = memcmp((void *) a->value, (void *) b->value, a->len);
 644
 645         return r;
 646 }
 647
 648 static int meta_var_change(struct meta_value *dst, struct nlattr *nla)
 649 {
 650         int len = nla_len(nla);
 651
 652         dst->val = (unsigned long)kmemdup(nla_data(nla), len, GFP_KERNEL);
 653         if (dst->val == 0UL)
 654                 return -ENOMEM;
 655         dst->len = len;
 656         return 0;
 657 }
 658
 659 static void meta_var_destroy(struct meta_value *v)
 660 {
 661         kfree((void *) v->val);
 662 }
 663
 664 static void meta_var_apply_extras(struct meta_value *v,
 665                                   struct meta_obj *dst)
 666 {
 667         int shift = v->hdr.shift;
 668
 669         if (shift && shift < dst->len)
 670                 dst->len -= shift;
 671 }
 672
 673 static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 674 {
 675         if (v->val && v->len &&
 676             nla_put(skb, tlv, v->len, (void *) v->val))
 677                 goto nla_put_failure;
 678         return 0;
 679
 680 nla_put_failure:
 681         return -1;
 682 }
 683
 684 /**************************************************************************
 685  * Type specific operations for TCF_META_TYPE_INT
 686  **************************************************************************/
 687
 688 static int meta_int_compare(struct meta_obj *a, struct meta_obj *b)
 689 {
 690         /* Let gcc optimize it, the unlikely is not really based on
 691          * some numbers but jump free code for mismatches seems
 692          * more logical. */
 693         if (unlikely(a->value == b->value))
 694                 return 0;
 695         else if (a->value < b->value)
 696                 return -1;
 697         else
 698                 return 1;
 699 }
 700
 701 static int meta_int_change(struct meta_value *dst, struct nlattr *nla)
 702 {
 703         if (nla_len(nla) >= sizeof(unsigned long)) {
 704                 dst->val = *(unsigned long *) nla_data(nla);
 705                 dst->len = sizeof(unsigned long);
 706         } else if (nla_len(nla) == sizeof(u32)) {
 707                 dst->val = nla_get_u32(nla);
 708                 dst->len = sizeof(u32);
 709         } else
 710                 return -EINVAL;
 711
 712         return 0;
 713 }
 714
 715 static void meta_int_apply_extras(struct meta_value *v,
 716                                   struct meta_obj *dst)
 717 {
 718         if (v->hdr.shift)
 719                 dst->value >>= v->hdr.shift;
 720
 721         if (v->val)
 722                 dst->value &= v->val;
 723 }
 724
 725 static int meta_int_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 726 {
 727         if (v->len == sizeof(unsigned long)) {
 728                 if (nla_put(skb, tlv, sizeof(unsigned long), &v->val))
 729                         goto nla_put_failure;
 730         } else if (v->len == sizeof(u32)) {
 731                 if (nla_put_u32(skb, tlv, v->val))
 732                         goto nla_put_failure;
 733         }
 734
 735         return 0;
 736
 737 nla_put_failure:
 738         return -1;
 739 }
 740
 741 /**************************************************************************
 742  * Type specific operations table
 743  **************************************************************************/
 744
 745 struct meta_type_ops {
 746         void    (*destroy)(struct meta_value *);
 747         int     (*compare)(struct meta_obj *, struct meta_obj *);
 748         int     (*change)(struct meta_value *, struct nlattr *);
 749         void    (*apply_extras)(struct meta_value *, struct meta_obj *);
 750         int     (*dump)(struct sk_buff *, struct meta_value *, int);
 751 };
 752
 753 static struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX + 1] = {
 754         [TCF_META_TYPE_VAR] = {
 755                 .destroy = meta_var_destroy,
 756                 .compare = meta_var_compare,
 757                 .change = meta_var_change,
 758                 .apply_extras = meta_var_apply_extras,
 759                 .dump = meta_var_dump
 760         },
 761         [TCF_META_TYPE_INT] = {
 762                 .compare = meta_int_compare,
 763                 .change = meta_int_change,
 764                 .apply_extras = meta_int_apply_extras,
 765                 .dump = meta_int_dump
 766         }
 767 };
 768
 769 static inline struct meta_type_ops *meta_type_ops(struct meta_value *v)
 770 {
 771         return &__meta_type_ops[meta_type(v)];
 772 }
 773
 774 /**************************************************************************
 775  * Core
 776  **************************************************************************/
 777
 778 static int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info,
 779                     struct meta_value *v, struct meta_obj *dst)
 780 {
 781         int err = 0;
 782
 783         if (meta_id(v) == TCF_META_ID_VALUE) {
 784                 dst->value = v->val;
 785                 dst->len = v->len;
 786                 return 0;
 787         }
 788
 789         meta_ops(v)->get(skb, info, v, dst, &err);
 790         if (err < 0)
 791                 return err;
 792
 793         if (meta_type_ops(v)->apply_extras)
 794                 meta_type_ops(v)->apply_extras(v, dst);
 795
 796         return 0;
 797 }
 798
 799 static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
 800                          struct tcf_pkt_info *info)
 801 {
 802         int r;
 803         struct meta_match *meta = (struct meta_match *) m->data;
 804         struct meta_obj l_value, r_value;
 805
 806         if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 ||
 807             meta_get(skb, info, &meta->rvalue, &r_value) < 0)
 808                 return 0;
 809
 810         r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value);
 811
 812         switch (meta->lvalue.hdr.op) {
 813         case TCF_EM_OPND_EQ:
 814                 return !r;
 815         case TCF_EM_OPND_LT:
 816                 return r < 0;
 817         case TCF_EM_OPND_GT:
 818                 return r > 0;
 819         }
 820
 821         return 0;
 822 }
 823
 824 static void meta_delete(struct meta_match *meta)
 825 {
 826         if (meta) {
 827                 struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
 828
 829                 if (ops && ops->destroy) {
 830                         ops->destroy(&meta->lvalue);
 831                         ops->destroy(&meta->rvalue);
 832                 }
 833         }
 834
 835         kfree(meta);
 836 }
 837
 838 static inline int meta_change_data(struct meta_value *dst, struct nlattr *nla)
 839 {
 840         if (nla) {
 841                 if (nla_len(nla) == 0)
 842                         return -EINVAL;
 843
 844                 return meta_type_ops(dst)->change(dst, nla);
 845         }
 846
 847         return 0;
 848 }
 849
 850 static inline int meta_is_supported(struct meta_value *val)
 851 {
 852         return !meta_id(val) || meta_ops(val)->get;
 853 }
 854
 855 static const struct nla_policy meta_policy[TCA_EM_META_MAX + 1] = {
 856         [TCA_EM_META_HDR]       = { .len = sizeof(struct tcf_meta_hdr) },
 857 };
 858
 859 static int em_meta_change(struct tcf_proto *tp, void *data, int len,
 860                           struct tcf_ematch *m)
 861 {
 862         int err;
 863         struct nlattr *tb[TCA_EM_META_MAX + 1];
 864         struct tcf_meta_hdr *hdr;
 865         struct meta_match *meta = NULL;
 866
 867         err = nla_parse(tb, TCA_EM_META_MAX, data, len, meta_policy);
 868         if (err < 0)
 869                 goto errout;
 870
 871         err = -EINVAL;
 872         if (tb[TCA_EM_META_HDR] == NULL)
 873                 goto errout;
 874         hdr = nla_data(tb[TCA_EM_META_HDR]);
 875
 876         if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) ||
 877             TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX ||
 878             TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX ||
 879             TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX)
 880                 goto errout;
 881
 882         meta = kzalloc(sizeof(*meta), GFP_KERNEL);
 883         if (meta == NULL) {
 884                 err = -ENOMEM;
 885                 goto errout;
 886         }
 887
 888         memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));
 889         memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right));
 890
 891         if (!meta_is_supported(&meta->lvalue) ||
 892             !meta_is_supported(&meta->rvalue)) {
 893                 err = -EOPNOTSUPP;
 894                 goto errout;
 895         }
 896
 897         if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE]) < 0 ||
 898             meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE]) < 0)
 899                 goto errout;
 900
 901         m->datalen = sizeof(*meta);
 902         m->data = (unsigned long) meta;
 903
 904         err = 0;
 905 errout:
 906         if (err && meta)
 907                 meta_delete(meta);
 908         return err;
 909 }
 910
 911 static void em_meta_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
 912 {
 913         if (m)
 914                 meta_delete((struct meta_match *) m->data);
 915 }
 916
 917 static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em)
 918 {
 919         struct meta_match *meta = (struct meta_match *) em->data;
 920         struct tcf_meta_hdr hdr;
 921         struct meta_type_ops *ops;
 922
 923         memset(&hdr, 0, sizeof(hdr));
 924         memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left));
 925         memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right));
 926
 927         if (nla_put(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr))
 928                 goto nla_put_failure;
 929
 930         ops = meta_type_ops(&meta->lvalue);
 931         if (ops->dump(skb, &meta->lvalue, TCA_EM_META_LVALUE) < 0 ||
 932             ops->dump(skb, &meta->rvalue, TCA_EM_META_RVALUE) < 0)
 933                 goto nla_put_failure;
 934
 935         return 0;
 936
 937 nla_put_failure:
 938         return -1;
 939 }
 940
 941 static struct tcf_ematch_ops em_meta_ops = {
 942         .kind     = TCF_EM_META,
 943         .change   = em_meta_change,
 944         .match    = em_meta_match,
 945         .destroy  = em_meta_destroy,
 946         .dump     = em_meta_dump,
 947         .owner    = THIS_MODULE,
 948         .link     = LIST_HEAD_INIT(em_meta_ops.link)
 949 };
 950
 951 static int __init init_em_meta(void)
 952 {
 953         return tcf_em_register(&em_meta_ops);
 954 }
 955
 956 static void __exit exit_em_meta(void)
 957 {
 958         tcf_em_unregister(&em_meta_ops);
 959 }
 960
 961 MODULE_LICENSE("GPL");
 962
 963 module_init(init_em_meta);
 964 module_exit(exit_em_meta);
 965
 966 MODULE_ALIAS_TCF_EMATCH(TCF_EM_META);