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  *      Additionaly, type dependant 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/module.h>
  62 #include <linux/types.h>
  63 #include <linux/kernel.h>
  64 #include <linux/sched.h>
  65 #include <linux/string.h>
  66 #include <linux/skbuff.h>
  67 #include <linux/random.h>
  68 #include <linux/if_vlan.h>
  69 #include <linux/tc_ematch/tc_em_meta.h>
  70 #include <net/dst.h>
  71 #include <net/route.h>
  72 #include <net/pkt_cls.h>
  73 #include <net/sock.h>
  74
  75 struct meta_obj
  76 {
  77         unsigned long           value;
  78         unsigned int            len;
  79 };
  80
  81 struct meta_value
  82 {
  83         struct tcf_meta_val     hdr;
  84         unsigned long           val;
  85         unsigned int            len;
  86 };
  87
  88 struct meta_match
  89 {
  90         struct meta_value       lvalue;
  91         struct meta_value       rvalue;
  92 };
  93
  94 static inline int meta_id(struct meta_value *v)
  95 {
  96         return TCF_META_ID(v->hdr.kind);
  97 }
  98
  99 static inline int meta_type(struct meta_value *v)
 100 {
 101         return TCF_META_TYPE(v->hdr.kind);
 102 }
 103
 104 #define META_COLLECTOR(FUNC) static void meta_##FUNC(struct sk_buff *skb, \
 105         struct tcf_pkt_info *info, struct meta_value *v, \
 106         struct meta_obj *dst, int *err)
 107
 108 /**************************************************************************
 109  * System status & misc
 110  **************************************************************************/
 111
 112 META_COLLECTOR(int_random)
 113 {
 114         get_random_bytes(&dst->value, sizeof(dst->value));
 115 }
 116
 117 static inline unsigned long fixed_loadavg(int load)
 118 {
 119         int rnd_load = load + (FIXED_1/200);
 120         int rnd_frac = ((rnd_load & (FIXED_1-1)) * 100) >> FSHIFT;
 121
 122         return ((rnd_load >> FSHIFT) * 100) + rnd_frac;
 123 }
 124
 125 META_COLLECTOR(int_loadavg_0)
 126 {
 127         dst->value = fixed_loadavg(avenrun[0]);
 128 }
 129
 130 META_COLLECTOR(int_loadavg_1)
 131 {
 132         dst->value = fixed_loadavg(avenrun[1]);
 133 }
 134
 135 META_COLLECTOR(int_loadavg_2)
 136 {
 137         dst->value = fixed_loadavg(avenrun[2]);
 138 }
 139
 140 /**************************************************************************
 141  * Device names & indices
 142  **************************************************************************/
 143
 144 static inline int int_dev(struct net_device *dev, struct meta_obj *dst)
 145 {
 146         if (unlikely(dev == NULL))
 147                 return -1;
 148
 149         dst->value = dev->ifindex;
 150         return 0;
 151 }
 152
 153 static inline int var_dev(struct net_device *dev, struct meta_obj *dst)
 154 {
 155         if (unlikely(dev == NULL))
 156                 return -1;
 157
 158         dst->value = (unsigned long) dev->name;
 159         dst->len = strlen(dev->name);
 160         return 0;
 161 }
 162
 163 META_COLLECTOR(int_dev)
 164 {
 165         *err = int_dev(skb->dev, dst);
 166 }
 167
 168 META_COLLECTOR(var_dev)
 169 {
 170         *err = var_dev(skb->dev, dst);
 171 }
 172
 173 /**************************************************************************
 174  * vlan tag
 175  **************************************************************************/
 176
 177 META_COLLECTOR(int_vlan_tag)
 178 {
 179         unsigned short uninitialized_var(tag);
 180         if (vlan_get_tag(skb, &tag) < 0)
 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 /**************************************************************************
 224  * Netfilter
 225  **************************************************************************/
 226
 227 META_COLLECTOR(int_mark)
 228 {
 229         dst->value = skb->mark;
 230 }
 231
 232 /**************************************************************************
 233  * Traffic Control
 234  **************************************************************************/
 235
 236 META_COLLECTOR(int_tcindex)
 237 {
 238         dst->value = skb->tc_index;
 239 }
 240
 241 /**************************************************************************
 242  * Routing
 243  **************************************************************************/
 244
 245 META_COLLECTOR(int_rtclassid)
 246 {
 247         if (unlikely(skb->dst == NULL))
 248                 *err = -1;
 249         else
 250 #ifdef CONFIG_NET_CLS_ROUTE
 251                 dst->value = skb->dst->tclassid;
 252 #else
 253                 dst->value = 0;
 254 #endif
 255 }
 256
 257 META_COLLECTOR(int_rtiif)
 258 {
 259         if (unlikely(skb->rtable == NULL))
 260                 *err = -1;
 261         else
 262                 dst->value = skb->rtable->fl.iif;
 263 }
 264
 265 /**************************************************************************
 266  * Socket Attributes
 267  **************************************************************************/
 268
 269 #define SKIP_NONLOCAL(skb)                      \
 270         if (unlikely(skb->sk == NULL)) {        \
 271                 *err = -1;                      \
 272                 return;                         \
 273         }
 274
 275 META_COLLECTOR(int_sk_family)
 276 {
 277         SKIP_NONLOCAL(skb);
 278         dst->value = skb->sk->sk_family;
 279 }
 280
 281 META_COLLECTOR(int_sk_state)
 282 {
 283         SKIP_NONLOCAL(skb);
 284         dst->value = skb->sk->sk_state;
 285 }
 286
 287 META_COLLECTOR(int_sk_reuse)
 288 {
 289         SKIP_NONLOCAL(skb);
 290         dst->value = skb->sk->sk_reuse;
 291 }
 292
 293 META_COLLECTOR(int_sk_bound_if)
 294 {
 295         SKIP_NONLOCAL(skb);
 296         /* No error if bound_dev_if is 0, legal userspace check */
 297         dst->value = skb->sk->sk_bound_dev_if;
 298 }
 299
 300 META_COLLECTOR(var_sk_bound_if)
 301 {
 302         SKIP_NONLOCAL(skb);
 303
 304          if (skb->sk->sk_bound_dev_if == 0) {
 305                 dst->value = (unsigned long) "any";
 306                 dst->len = 3;
 307          } else  {
 308                 struct net_device *dev;
 309
 310                 dev = dev_get_by_index(&init_net, skb->sk->sk_bound_dev_if);
 311                 *err = var_dev(dev, dst);
 312                 if (dev)
 313                         dev_put(dev);
 314          }
 315 }
 316
 317 META_COLLECTOR(int_sk_refcnt)
 318 {
 319         SKIP_NONLOCAL(skb);
 320         dst->value = atomic_read(&skb->sk->sk_refcnt);
 321 }
 322
 323 META_COLLECTOR(int_sk_rcvbuf)
 324 {
 325         SKIP_NONLOCAL(skb);
 326         dst->value = skb->sk->sk_rcvbuf;
 327 }
 328
 329 META_COLLECTOR(int_sk_shutdown)
 330 {
 331         SKIP_NONLOCAL(skb);
 332         dst->value = skb->sk->sk_shutdown;
 333 }
 334
 335 META_COLLECTOR(int_sk_proto)
 336 {
 337         SKIP_NONLOCAL(skb);
 338         dst->value = skb->sk->sk_protocol;
 339 }
 340
 341 META_COLLECTOR(int_sk_type)
 342 {
 343         SKIP_NONLOCAL(skb);
 344         dst->value = skb->sk->sk_type;
 345 }
 346
 347 META_COLLECTOR(int_sk_rmem_alloc)
 348 {
 349         SKIP_NONLOCAL(skb);
 350         dst->value = atomic_read(&skb->sk->sk_rmem_alloc);
 351 }
 352
 353 META_COLLECTOR(int_sk_wmem_alloc)
 354 {
 355         SKIP_NONLOCAL(skb);
 356         dst->value = atomic_read(&skb->sk->sk_wmem_alloc);
 357 }
 358
 359 META_COLLECTOR(int_sk_omem_alloc)
 360 {
 361         SKIP_NONLOCAL(skb);
 362         dst->value = atomic_read(&skb->sk->sk_omem_alloc);
 363 }
 364
 365 META_COLLECTOR(int_sk_rcv_qlen)
 366 {
 367         SKIP_NONLOCAL(skb);
 368         dst->value = skb->sk->sk_receive_queue.qlen;
 369 }
 370
 371 META_COLLECTOR(int_sk_snd_qlen)
 372 {
 373         SKIP_NONLOCAL(skb);
 374         dst->value = skb->sk->sk_write_queue.qlen;
 375 }
 376
 377 META_COLLECTOR(int_sk_wmem_queued)
 378 {
 379         SKIP_NONLOCAL(skb);
 380         dst->value = skb->sk->sk_wmem_queued;
 381 }
 382
 383 META_COLLECTOR(int_sk_fwd_alloc)
 384 {
 385         SKIP_NONLOCAL(skb);
 386         dst->value = skb->sk->sk_forward_alloc;
 387 }
 388
 389 META_COLLECTOR(int_sk_sndbuf)
 390 {
 391         SKIP_NONLOCAL(skb);
 392         dst->value = skb->sk->sk_sndbuf;
 393 }
 394
 395 META_COLLECTOR(int_sk_alloc)
 396 {
 397         SKIP_NONLOCAL(skb);
 398         dst->value = skb->sk->sk_allocation;
 399 }
 400
 401 META_COLLECTOR(int_sk_route_caps)
 402 {
 403         SKIP_NONLOCAL(skb);
 404         dst->value = skb->sk->sk_route_caps;
 405 }
 406
 407 META_COLLECTOR(int_sk_hash)
 408 {
 409         SKIP_NONLOCAL(skb);
 410         dst->value = skb->sk->sk_hash;
 411 }
 412
 413 META_COLLECTOR(int_sk_lingertime)
 414 {
 415         SKIP_NONLOCAL(skb);
 416         dst->value = skb->sk->sk_lingertime / HZ;
 417 }
 418
 419 META_COLLECTOR(int_sk_err_qlen)
 420 {
 421         SKIP_NONLOCAL(skb);
 422         dst->value = skb->sk->sk_error_queue.qlen;
 423 }
 424
 425 META_COLLECTOR(int_sk_ack_bl)
 426 {
 427         SKIP_NONLOCAL(skb);
 428         dst->value = skb->sk->sk_ack_backlog;
 429 }
 430
 431 META_COLLECTOR(int_sk_max_ack_bl)
 432 {
 433         SKIP_NONLOCAL(skb);
 434         dst->value = skb->sk->sk_max_ack_backlog;
 435 }
 436
 437 META_COLLECTOR(int_sk_prio)
 438 {
 439         SKIP_NONLOCAL(skb);
 440         dst->value = skb->sk->sk_priority;
 441 }
 442
 443 META_COLLECTOR(int_sk_rcvlowat)
 444 {
 445         SKIP_NONLOCAL(skb);
 446         dst->value = skb->sk->sk_rcvlowat;
 447 }
 448
 449 META_COLLECTOR(int_sk_rcvtimeo)
 450 {
 451         SKIP_NONLOCAL(skb);
 452         dst->value = skb->sk->sk_rcvtimeo / HZ;
 453 }
 454
 455 META_COLLECTOR(int_sk_sndtimeo)
 456 {
 457         SKIP_NONLOCAL(skb);
 458         dst->value = skb->sk->sk_sndtimeo / HZ;
 459 }
 460
 461 META_COLLECTOR(int_sk_sendmsg_off)
 462 {
 463         SKIP_NONLOCAL(skb);
 464         dst->value = skb->sk->sk_sndmsg_off;
 465 }
 466
 467 META_COLLECTOR(int_sk_write_pend)
 468 {
 469         SKIP_NONLOCAL(skb);
 470         dst->value = skb->sk->sk_write_pending;
 471 }
 472
 473 /**************************************************************************
 474  * Meta value collectors assignment table
 475  **************************************************************************/
 476
 477 struct meta_ops
 478 {
 479         void            (*get)(struct sk_buff *, struct tcf_pkt_info *,
 480                                struct meta_value *, struct meta_obj *, int *);
 481 };
 482
 483 #define META_ID(name) TCF_META_ID_##name
 484 #define META_FUNC(name) { .get = meta_##name }
 485
 486 /* Meta value operations table listing all meta value collectors and
 487  * assigns them to a type and meta id. */
 488 static struct meta_ops __meta_ops[TCF_META_TYPE_MAX+1][TCF_META_ID_MAX+1] = {
 489         [TCF_META_TYPE_VAR] = {
 490                 [META_ID(DEV)]                  = META_FUNC(var_dev),
 491                 [META_ID(SK_BOUND_IF)]          = META_FUNC(var_sk_bound_if),
 492         },
 493         [TCF_META_TYPE_INT] = {
 494                 [META_ID(RANDOM)]               = META_FUNC(int_random),
 495                 [META_ID(LOADAVG_0)]            = META_FUNC(int_loadavg_0),
 496                 [META_ID(LOADAVG_1)]            = META_FUNC(int_loadavg_1),
 497                 [META_ID(LOADAVG_2)]            = META_FUNC(int_loadavg_2),
 498                 [META_ID(DEV)]                  = META_FUNC(int_dev),
 499                 [META_ID(PRIORITY)]             = META_FUNC(int_priority),
 500                 [META_ID(PROTOCOL)]             = META_FUNC(int_protocol),
 501                 [META_ID(PKTTYPE)]              = META_FUNC(int_pkttype),
 502                 [META_ID(PKTLEN)]               = META_FUNC(int_pktlen),
 503                 [META_ID(DATALEN)]              = META_FUNC(int_datalen),
 504                 [META_ID(MACLEN)]               = META_FUNC(int_maclen),
 505                 [META_ID(NFMARK)]               = META_FUNC(int_mark),
 506                 [META_ID(TCINDEX)]              = META_FUNC(int_tcindex),
 507                 [META_ID(RTCLASSID)]            = META_FUNC(int_rtclassid),
 508                 [META_ID(RTIIF)]                = META_FUNC(int_rtiif),
 509                 [META_ID(SK_FAMILY)]            = META_FUNC(int_sk_family),
 510                 [META_ID(SK_STATE)]             = META_FUNC(int_sk_state),
 511                 [META_ID(SK_REUSE)]             = META_FUNC(int_sk_reuse),
 512                 [META_ID(SK_BOUND_IF)]          = META_FUNC(int_sk_bound_if),
 513                 [META_ID(SK_REFCNT)]            = META_FUNC(int_sk_refcnt),
 514                 [META_ID(SK_RCVBUF)]            = META_FUNC(int_sk_rcvbuf),
 515                 [META_ID(SK_SNDBUF)]            = META_FUNC(int_sk_sndbuf),
 516                 [META_ID(SK_SHUTDOWN)]          = META_FUNC(int_sk_shutdown),
 517                 [META_ID(SK_PROTO)]             = META_FUNC(int_sk_proto),
 518                 [META_ID(SK_TYPE)]              = META_FUNC(int_sk_type),
 519                 [META_ID(SK_RMEM_ALLOC)]        = META_FUNC(int_sk_rmem_alloc),
 520                 [META_ID(SK_WMEM_ALLOC)]        = META_FUNC(int_sk_wmem_alloc),
 521                 [META_ID(SK_OMEM_ALLOC)]        = META_FUNC(int_sk_omem_alloc),
 522                 [META_ID(SK_WMEM_QUEUED)]       = META_FUNC(int_sk_wmem_queued),
 523                 [META_ID(SK_RCV_QLEN)]          = META_FUNC(int_sk_rcv_qlen),
 524                 [META_ID(SK_SND_QLEN)]          = META_FUNC(int_sk_snd_qlen),
 525                 [META_ID(SK_ERR_QLEN)]          = META_FUNC(int_sk_err_qlen),
 526                 [META_ID(SK_FORWARD_ALLOCS)]    = META_FUNC(int_sk_fwd_alloc),
 527                 [META_ID(SK_ALLOCS)]            = META_FUNC(int_sk_alloc),
 528                 [META_ID(SK_ROUTE_CAPS)]        = META_FUNC(int_sk_route_caps),
 529                 [META_ID(SK_HASH)]              = META_FUNC(int_sk_hash),
 530                 [META_ID(SK_LINGERTIME)]        = META_FUNC(int_sk_lingertime),
 531                 [META_ID(SK_ACK_BACKLOG)]       = META_FUNC(int_sk_ack_bl),
 532                 [META_ID(SK_MAX_ACK_BACKLOG)]   = META_FUNC(int_sk_max_ack_bl),
 533                 [META_ID(SK_PRIO)]              = META_FUNC(int_sk_prio),
 534                 [META_ID(SK_RCVLOWAT)]          = META_FUNC(int_sk_rcvlowat),
 535                 [META_ID(SK_RCVTIMEO)]          = META_FUNC(int_sk_rcvtimeo),
 536                 [META_ID(SK_SNDTIMEO)]          = META_FUNC(int_sk_sndtimeo),
 537                 [META_ID(SK_SENDMSG_OFF)]       = META_FUNC(int_sk_sendmsg_off),
 538                 [META_ID(SK_WRITE_PENDING)]     = META_FUNC(int_sk_write_pend),
 539                 [META_ID(VLAN_TAG)]             = META_FUNC(int_vlan_tag),
 540         }
 541 };
 542
 543 static inline struct meta_ops * meta_ops(struct meta_value *val)
 544 {
 545         return &__meta_ops[meta_type(val)][meta_id(val)];
 546 }
 547
 548 /**************************************************************************
 549  * Type specific operations for TCF_META_TYPE_VAR
 550  **************************************************************************/
 551
 552 static int meta_var_compare(struct meta_obj *a, struct meta_obj *b)
 553 {
 554         int r = a->len - b->len;
 555
 556         if (r == 0)
 557                 r = memcmp((void *) a->value, (void *) b->value, a->len);
 558
 559         return r;
 560 }
 561
 562 static int meta_var_change(struct meta_value *dst, struct nlattr *nla)
 563 {
 564         int len = nla_len(nla);
 565
 566         dst->val = (unsigned long)kmemdup(nla_data(nla), len, GFP_KERNEL);
 567         if (dst->val == 0UL)
 568                 return -ENOMEM;
 569         dst->len = len;
 570         return 0;
 571 }
 572
 573 static void meta_var_destroy(struct meta_value *v)
 574 {
 575         kfree((void *) v->val);
 576 }
 577
 578 static void meta_var_apply_extras(struct meta_value *v,
 579                                   struct meta_obj *dst)
 580 {
 581         int shift = v->hdr.shift;
 582
 583         if (shift && shift < dst->len)
 584                 dst->len -= shift;
 585 }
 586
 587 static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 588 {
 589         if (v->val && v->len)
 590                 NLA_PUT(skb, tlv, v->len, (void *) v->val);
 591         return 0;
 592
 593 nla_put_failure:
 594         return -1;
 595 }
 596
 597 /**************************************************************************
 598  * Type specific operations for TCF_META_TYPE_INT
 599  **************************************************************************/
 600
 601 static int meta_int_compare(struct meta_obj *a, struct meta_obj *b)
 602 {
 603         /* Let gcc optimize it, the unlikely is not really based on
 604          * some numbers but jump free code for mismatches seems
 605          * more logical. */
 606         if (unlikely(a->value == b->value))
 607                 return 0;
 608         else if (a->value < b->value)
 609                 return -1;
 610         else
 611                 return 1;
 612 }
 613
 614 static int meta_int_change(struct meta_value *dst, struct nlattr *nla)
 615 {
 616         if (nla_len(nla) >= sizeof(unsigned long)) {
 617                 dst->val = *(unsigned long *) nla_data(nla);
 618                 dst->len = sizeof(unsigned long);
 619         } else if (nla_len(nla) == sizeof(u32)) {
 620                 dst->val = nla_get_u32(nla);
 621                 dst->len = sizeof(u32);
 622         } else
 623                 return -EINVAL;
 624
 625         return 0;
 626 }
 627
 628 static void meta_int_apply_extras(struct meta_value *v,
 629                                   struct meta_obj *dst)
 630 {
 631         if (v->hdr.shift)
 632                 dst->value >>= v->hdr.shift;
 633
 634         if (v->val)
 635                 dst->value &= v->val;
 636 }
 637
 638 static int meta_int_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 639 {
 640         if (v->len == sizeof(unsigned long))
 641                 NLA_PUT(skb, tlv, sizeof(unsigned long), &v->val);
 642         else if (v->len == sizeof(u32)) {
 643                 NLA_PUT_U32(skb, tlv, v->val);
 644         }
 645
 646         return 0;
 647
 648 nla_put_failure:
 649         return -1;
 650 }
 651
 652 /**************************************************************************
 653  * Type specific operations table
 654  **************************************************************************/
 655
 656 struct meta_type_ops
 657 {
 658         void    (*destroy)(struct meta_value *);
 659         int     (*compare)(struct meta_obj *, struct meta_obj *);
 660         int     (*change)(struct meta_value *, struct nlattr *);
 661         void    (*apply_extras)(struct meta_value *, struct meta_obj *);
 662         int     (*dump)(struct sk_buff *, struct meta_value *, int);
 663 };
 664
 665 static struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX+1] = {
 666         [TCF_META_TYPE_VAR] = {
 667                 .destroy = meta_var_destroy,
 668                 .compare = meta_var_compare,
 669                 .change = meta_var_change,
 670                 .apply_extras = meta_var_apply_extras,
 671                 .dump = meta_var_dump
 672         },
 673         [TCF_META_TYPE_INT] = {
 674                 .compare = meta_int_compare,
 675                 .change = meta_int_change,
 676                 .apply_extras = meta_int_apply_extras,
 677                 .dump = meta_int_dump
 678         }
 679 };
 680
 681 static inline struct meta_type_ops * meta_type_ops(struct meta_value *v)
 682 {
 683         return &__meta_type_ops[meta_type(v)];
 684 }
 685
 686 /**************************************************************************
 687  * Core
 688  **************************************************************************/
 689
 690 static int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info,
 691                     struct meta_value *v, struct meta_obj *dst)
 692 {
 693         int err = 0;
 694
 695         if (meta_id(v) == TCF_META_ID_VALUE) {
 696                 dst->value = v->val;
 697                 dst->len = v->len;
 698                 return 0;
 699         }
 700
 701         meta_ops(v)->get(skb, info, v, dst, &err);
 702         if (err < 0)
 703                 return err;
 704
 705         if (meta_type_ops(v)->apply_extras)
 706             meta_type_ops(v)->apply_extras(v, dst);
 707
 708         return 0;
 709 }
 710
 711 static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
 712                          struct tcf_pkt_info *info)
 713 {
 714         int r;
 715         struct meta_match *meta = (struct meta_match *) m->data;
 716         struct meta_obj l_value, r_value;
 717
 718         if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 ||
 719             meta_get(skb, info, &meta->rvalue, &r_value) < 0)
 720                 return 0;
 721
 722         r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value);
 723
 724         switch (meta->lvalue.hdr.op) {
 725                 case TCF_EM_OPND_EQ:
 726                         return !r;
 727                 case TCF_EM_OPND_LT:
 728                         return r < 0;
 729                 case TCF_EM_OPND_GT:
 730                         return r > 0;
 731         }
 732
 733         return 0;
 734 }
 735
 736 static void meta_delete(struct meta_match *meta)
 737 {
 738         if (meta) {
 739                 struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
 740
 741                 if (ops && ops->destroy) {
 742                         ops->destroy(&meta->lvalue);
 743                         ops->destroy(&meta->rvalue);
 744                 }
 745         }
 746
 747         kfree(meta);
 748 }
 749
 750 static inline int meta_change_data(struct meta_value *dst, struct nlattr *nla)
 751 {
 752         if (nla) {
 753                 if (nla_len(nla) == 0)
 754                         return -EINVAL;
 755
 756                 return meta_type_ops(dst)->change(dst, nla);
 757         }
 758
 759         return 0;
 760 }
 761
 762 static inline int meta_is_supported(struct meta_value *val)
 763 {
 764         return (!meta_id(val) || meta_ops(val)->get);
 765 }
 766
 767 static const struct nla_policy meta_policy[TCA_EM_META_MAX + 1] = {
 768         [TCA_EM_META_HDR]       = { .len = sizeof(struct tcf_meta_hdr) },
 769 };
 770
 771 static int em_meta_change(struct tcf_proto *tp, void *data, int len,
 772                           struct tcf_ematch *m)
 773 {
 774         int err;
 775         struct nlattr *tb[TCA_EM_META_MAX + 1];
 776         struct tcf_meta_hdr *hdr;
 777         struct meta_match *meta = NULL;
 778
 779         err = nla_parse(tb, TCA_EM_META_MAX, data, len, meta_policy);
 780         if (err < 0)
 781                 goto errout;
 782
 783         err = -EINVAL;
 784         if (tb[TCA_EM_META_HDR] == NULL)
 785                 goto errout;
 786         hdr = nla_data(tb[TCA_EM_META_HDR]);
 787
 788         if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) ||
 789             TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX ||
 790             TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX ||
 791             TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX)
 792                 goto errout;
 793
 794         meta = kzalloc(sizeof(*meta), GFP_KERNEL);
 795         if (meta == NULL)
 796                 goto errout;
 797
 798         memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));
 799         memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right));
 800
 801         if (!meta_is_supported(&meta->lvalue) ||
 802             !meta_is_supported(&meta->rvalue)) {
 803                 err = -EOPNOTSUPP;
 804                 goto errout;
 805         }
 806
 807         if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE]) < 0 ||
 808             meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE]) < 0)
 809                 goto errout;
 810
 811         m->datalen = sizeof(*meta);
 812         m->data = (unsigned long) meta;
 813
 814         err = 0;
 815 errout:
 816         if (err && meta)
 817                 meta_delete(meta);
 818         return err;
 819 }
 820
 821 static void em_meta_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
 822 {
 823         if (m)
 824                 meta_delete((struct meta_match *) m->data);
 825 }
 826
 827 static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em)
 828 {
 829         struct meta_match *meta = (struct meta_match *) em->data;
 830         struct tcf_meta_hdr hdr;
 831         struct meta_type_ops *ops;
 832
 833         memset(&hdr, 0, sizeof(hdr));
 834         memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left));
 835         memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right));
 836
 837         NLA_PUT(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr);
 838
 839         ops = meta_type_ops(&meta->lvalue);
 840         if (ops->dump(skb, &meta->lvalue, TCA_EM_META_LVALUE) < 0 ||
 841             ops->dump(skb, &meta->rvalue, TCA_EM_META_RVALUE) < 0)
 842                 goto nla_put_failure;
 843
 844         return 0;
 845
 846 nla_put_failure:
 847         return -1;
 848 }
 849
 850 static struct tcf_ematch_ops em_meta_ops = {
 851         .kind     = TCF_EM_META,
 852         .change   = em_meta_change,
 853         .match    = em_meta_match,
 854         .destroy  = em_meta_destroy,
 855         .dump     = em_meta_dump,
 856         .owner    = THIS_MODULE,
 857         .link     = LIST_HEAD_INIT(em_meta_ops.link)
 858 };
 859
 860 static int __init init_em_meta(void)
 861 {
 862         return tcf_em_register(&em_meta_ops);
 863 }
 864
 865 static void __exit exit_em_meta(void)
 866 {
 867         tcf_em_unregister(&em_meta_ops);
 868 }
 869
 870 MODULE_LICENSE("GPL");
 871
 872 module_init(init_em_meta);
 873 module_exit(exit_em_meta);
 874
 875 MODULE_ALIAS_TCF_EMATCH(TCF_EM_META);