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 tag;
 180
 181         tag = vlan_tx_tag_get(skb);
 182         if (!tag && __vlan_get_tag(skb, &tag))
 183                 *err = -1;
 184         else
 185                 dst->value = tag;
 186 }
 187
 188
 189
 190 /**************************************************************************
 191  * skb attributes
 192  **************************************************************************/
 193
 194 META_COLLECTOR(int_priority)
 195 {
 196         dst->value = skb->priority;
 197 }
 198
 199 META_COLLECTOR(int_protocol)
 200 {
 201         /* Let userspace take care of the byte ordering */
 202         dst->value = skb->protocol;
 203 }
 204
 205 META_COLLECTOR(int_pkttype)
 206 {
 207         dst->value = skb->pkt_type;
 208 }
 209
 210 META_COLLECTOR(int_pktlen)
 211 {
 212         dst->value = skb->len;
 213 }
 214
 215 META_COLLECTOR(int_datalen)
 216 {
 217         dst->value = skb->data_len;
 218 }
 219
 220 META_COLLECTOR(int_maclen)
 221 {
 222         dst->value = skb->mac_len;
 223 }
 224
 225 /**************************************************************************
 226  * Netfilter
 227  **************************************************************************/
 228
 229 META_COLLECTOR(int_mark)
 230 {
 231         dst->value = skb->mark;
 232 }
 233
 234 /**************************************************************************
 235  * Traffic Control
 236  **************************************************************************/
 237
 238 META_COLLECTOR(int_tcindex)
 239 {
 240         dst->value = skb->tc_index;
 241 }
 242
 243 /**************************************************************************
 244  * Routing
 245  **************************************************************************/
 246
 247 META_COLLECTOR(int_rtclassid)
 248 {
 249         if (unlikely(skb_dst(skb) == NULL))
 250                 *err = -1;
 251         else
 252 #ifdef CONFIG_NET_CLS_ROUTE
 253                 dst->value = skb_dst(skb)->tclassid;
 254 #else
 255                 dst->value = 0;
 256 #endif
 257 }
 258
 259 META_COLLECTOR(int_rtiif)
 260 {
 261         if (unlikely(skb_rtable(skb) == NULL))
 262                 *err = -1;
 263         else
 264                 dst->value = skb_rtable(skb)->fl.iif;
 265 }
 266
 267 /**************************************************************************
 268  * Socket Attributes
 269  **************************************************************************/
 270
 271 #define SKIP_NONLOCAL(skb)                      \
 272         if (unlikely(skb->sk == NULL)) {        \
 273                 *err = -1;                      \
 274                 return;                         \
 275         }
 276
 277 META_COLLECTOR(int_sk_family)
 278 {
 279         SKIP_NONLOCAL(skb);
 280         dst->value = skb->sk->sk_family;
 281 }
 282
 283 META_COLLECTOR(int_sk_state)
 284 {
 285         SKIP_NONLOCAL(skb);
 286         dst->value = skb->sk->sk_state;
 287 }
 288
 289 META_COLLECTOR(int_sk_reuse)
 290 {
 291         SKIP_NONLOCAL(skb);
 292         dst->value = skb->sk->sk_reuse;
 293 }
 294
 295 META_COLLECTOR(int_sk_bound_if)
 296 {
 297         SKIP_NONLOCAL(skb);
 298         /* No error if bound_dev_if is 0, legal userspace check */
 299         dst->value = skb->sk->sk_bound_dev_if;
 300 }
 301
 302 META_COLLECTOR(var_sk_bound_if)
 303 {
 304         SKIP_NONLOCAL(skb);
 305
 306          if (skb->sk->sk_bound_dev_if == 0) {
 307                 dst->value = (unsigned long) "any";
 308                 dst->len = 3;
 309          } else  {
 310                 struct net_device *dev;
 311
 312                 dev = dev_get_by_index(&init_net, skb->sk->sk_bound_dev_if);
 313                 *err = var_dev(dev, dst);
 314                 if (dev)
 315                         dev_put(dev);
 316          }
 317 }
 318
 319 META_COLLECTOR(int_sk_refcnt)
 320 {
 321         SKIP_NONLOCAL(skb);
 322         dst->value = atomic_read(&skb->sk->sk_refcnt);
 323 }
 324
 325 META_COLLECTOR(int_sk_rcvbuf)
 326 {
 327         SKIP_NONLOCAL(skb);
 328         dst->value = skb->sk->sk_rcvbuf;
 329 }
 330
 331 META_COLLECTOR(int_sk_shutdown)
 332 {
 333         SKIP_NONLOCAL(skb);
 334         dst->value = skb->sk->sk_shutdown;
 335 }
 336
 337 META_COLLECTOR(int_sk_proto)
 338 {
 339         SKIP_NONLOCAL(skb);
 340         dst->value = skb->sk->sk_protocol;
 341 }
 342
 343 META_COLLECTOR(int_sk_type)
 344 {
 345         SKIP_NONLOCAL(skb);
 346         dst->value = skb->sk->sk_type;
 347 }
 348
 349 META_COLLECTOR(int_sk_rmem_alloc)
 350 {
 351         SKIP_NONLOCAL(skb);
 352         dst->value = sk_rmem_alloc_get(skb->sk);
 353 }
 354
 355 META_COLLECTOR(int_sk_wmem_alloc)
 356 {
 357         SKIP_NONLOCAL(skb);
 358         dst->value = sk_wmem_alloc_get(skb->sk);
 359 }
 360
 361 META_COLLECTOR(int_sk_omem_alloc)
 362 {
 363         SKIP_NONLOCAL(skb);
 364         dst->value = atomic_read(&skb->sk->sk_omem_alloc);
 365 }
 366
 367 META_COLLECTOR(int_sk_rcv_qlen)
 368 {
 369         SKIP_NONLOCAL(skb);
 370         dst->value = skb->sk->sk_receive_queue.qlen;
 371 }
 372
 373 META_COLLECTOR(int_sk_snd_qlen)
 374 {
 375         SKIP_NONLOCAL(skb);
 376         dst->value = skb->sk->sk_write_queue.qlen;
 377 }
 378
 379 META_COLLECTOR(int_sk_wmem_queued)
 380 {
 381         SKIP_NONLOCAL(skb);
 382         dst->value = skb->sk->sk_wmem_queued;
 383 }
 384
 385 META_COLLECTOR(int_sk_fwd_alloc)
 386 {
 387         SKIP_NONLOCAL(skb);
 388         dst->value = skb->sk->sk_forward_alloc;
 389 }
 390
 391 META_COLLECTOR(int_sk_sndbuf)
 392 {
 393         SKIP_NONLOCAL(skb);
 394         dst->value = skb->sk->sk_sndbuf;
 395 }
 396
 397 META_COLLECTOR(int_sk_alloc)
 398 {
 399         SKIP_NONLOCAL(skb);
 400         dst->value = skb->sk->sk_allocation;
 401 }
 402
 403 META_COLLECTOR(int_sk_route_caps)
 404 {
 405         SKIP_NONLOCAL(skb);
 406         dst->value = skb->sk->sk_route_caps;
 407 }
 408
 409 META_COLLECTOR(int_sk_hash)
 410 {
 411         SKIP_NONLOCAL(skb);
 412         dst->value = skb->sk->sk_hash;
 413 }
 414
 415 META_COLLECTOR(int_sk_lingertime)
 416 {
 417         SKIP_NONLOCAL(skb);
 418         dst->value = skb->sk->sk_lingertime / HZ;
 419 }
 420
 421 META_COLLECTOR(int_sk_err_qlen)
 422 {
 423         SKIP_NONLOCAL(skb);
 424         dst->value = skb->sk->sk_error_queue.qlen;
 425 }
 426
 427 META_COLLECTOR(int_sk_ack_bl)
 428 {
 429         SKIP_NONLOCAL(skb);
 430         dst->value = skb->sk->sk_ack_backlog;
 431 }
 432
 433 META_COLLECTOR(int_sk_max_ack_bl)
 434 {
 435         SKIP_NONLOCAL(skb);
 436         dst->value = skb->sk->sk_max_ack_backlog;
 437 }
 438
 439 META_COLLECTOR(int_sk_prio)
 440 {
 441         SKIP_NONLOCAL(skb);
 442         dst->value = skb->sk->sk_priority;
 443 }
 444
 445 META_COLLECTOR(int_sk_rcvlowat)
 446 {
 447         SKIP_NONLOCAL(skb);
 448         dst->value = skb->sk->sk_rcvlowat;
 449 }
 450
 451 META_COLLECTOR(int_sk_rcvtimeo)
 452 {
 453         SKIP_NONLOCAL(skb);
 454         dst->value = skb->sk->sk_rcvtimeo / HZ;
 455 }
 456
 457 META_COLLECTOR(int_sk_sndtimeo)
 458 {
 459         SKIP_NONLOCAL(skb);
 460         dst->value = skb->sk->sk_sndtimeo / HZ;
 461 }
 462
 463 META_COLLECTOR(int_sk_sendmsg_off)
 464 {
 465         SKIP_NONLOCAL(skb);
 466         dst->value = skb->sk->sk_sndmsg_off;
 467 }
 468
 469 META_COLLECTOR(int_sk_write_pend)
 470 {
 471         SKIP_NONLOCAL(skb);
 472         dst->value = skb->sk->sk_write_pending;
 473 }
 474
 475 /**************************************************************************
 476  * Meta value collectors assignment table
 477  **************************************************************************/
 478
 479 struct meta_ops
 480 {
 481         void            (*get)(struct sk_buff *, struct tcf_pkt_info *,
 482                                struct meta_value *, struct meta_obj *, int *);
 483 };
 484
 485 #define META_ID(name) TCF_META_ID_##name
 486 #define META_FUNC(name) { .get = meta_##name }
 487
 488 /* Meta value operations table listing all meta value collectors and
 489  * assigns them to a type and meta id. */
 490 static struct meta_ops __meta_ops[TCF_META_TYPE_MAX+1][TCF_META_ID_MAX+1] = {
 491         [TCF_META_TYPE_VAR] = {
 492                 [META_ID(DEV)]                  = META_FUNC(var_dev),
 493                 [META_ID(SK_BOUND_IF)]          = META_FUNC(var_sk_bound_if),
 494         },
 495         [TCF_META_TYPE_INT] = {
 496                 [META_ID(RANDOM)]               = META_FUNC(int_random),
 497                 [META_ID(LOADAVG_0)]            = META_FUNC(int_loadavg_0),
 498                 [META_ID(LOADAVG_1)]            = META_FUNC(int_loadavg_1),
 499                 [META_ID(LOADAVG_2)]            = META_FUNC(int_loadavg_2),
 500                 [META_ID(DEV)]                  = META_FUNC(int_dev),
 501                 [META_ID(PRIORITY)]             = META_FUNC(int_priority),
 502                 [META_ID(PROTOCOL)]             = META_FUNC(int_protocol),
 503                 [META_ID(PKTTYPE)]              = META_FUNC(int_pkttype),
 504                 [META_ID(PKTLEN)]               = META_FUNC(int_pktlen),
 505                 [META_ID(DATALEN)]              = META_FUNC(int_datalen),
 506                 [META_ID(MACLEN)]               = META_FUNC(int_maclen),
 507                 [META_ID(NFMARK)]               = META_FUNC(int_mark),
 508                 [META_ID(TCINDEX)]              = META_FUNC(int_tcindex),
 509                 [META_ID(RTCLASSID)]            = META_FUNC(int_rtclassid),
 510                 [META_ID(RTIIF)]                = META_FUNC(int_rtiif),
 511                 [META_ID(SK_FAMILY)]            = META_FUNC(int_sk_family),
 512                 [META_ID(SK_STATE)]             = META_FUNC(int_sk_state),
 513                 [META_ID(SK_REUSE)]             = META_FUNC(int_sk_reuse),
 514                 [META_ID(SK_BOUND_IF)]          = META_FUNC(int_sk_bound_if),
 515                 [META_ID(SK_REFCNT)]            = META_FUNC(int_sk_refcnt),
 516                 [META_ID(SK_RCVBUF)]            = META_FUNC(int_sk_rcvbuf),
 517                 [META_ID(SK_SNDBUF)]            = META_FUNC(int_sk_sndbuf),
 518                 [META_ID(SK_SHUTDOWN)]          = META_FUNC(int_sk_shutdown),
 519                 [META_ID(SK_PROTO)]             = META_FUNC(int_sk_proto),
 520                 [META_ID(SK_TYPE)]              = META_FUNC(int_sk_type),
 521                 [META_ID(SK_RMEM_ALLOC)]        = META_FUNC(int_sk_rmem_alloc),
 522                 [META_ID(SK_WMEM_ALLOC)]        = META_FUNC(int_sk_wmem_alloc),
 523                 [META_ID(SK_OMEM_ALLOC)]        = META_FUNC(int_sk_omem_alloc),
 524                 [META_ID(SK_WMEM_QUEUED)]       = META_FUNC(int_sk_wmem_queued),
 525                 [META_ID(SK_RCV_QLEN)]          = META_FUNC(int_sk_rcv_qlen),
 526                 [META_ID(SK_SND_QLEN)]          = META_FUNC(int_sk_snd_qlen),
 527                 [META_ID(SK_ERR_QLEN)]          = META_FUNC(int_sk_err_qlen),
 528                 [META_ID(SK_FORWARD_ALLOCS)]    = META_FUNC(int_sk_fwd_alloc),
 529                 [META_ID(SK_ALLOCS)]            = META_FUNC(int_sk_alloc),
 530                 [META_ID(SK_ROUTE_CAPS)]        = META_FUNC(int_sk_route_caps),
 531                 [META_ID(SK_HASH)]              = META_FUNC(int_sk_hash),
 532                 [META_ID(SK_LINGERTIME)]        = META_FUNC(int_sk_lingertime),
 533                 [META_ID(SK_ACK_BACKLOG)]       = META_FUNC(int_sk_ack_bl),
 534                 [META_ID(SK_MAX_ACK_BACKLOG)]   = META_FUNC(int_sk_max_ack_bl),
 535                 [META_ID(SK_PRIO)]              = META_FUNC(int_sk_prio),
 536                 [META_ID(SK_RCVLOWAT)]          = META_FUNC(int_sk_rcvlowat),
 537                 [META_ID(SK_RCVTIMEO)]          = META_FUNC(int_sk_rcvtimeo),
 538                 [META_ID(SK_SNDTIMEO)]          = META_FUNC(int_sk_sndtimeo),
 539                 [META_ID(SK_SENDMSG_OFF)]       = META_FUNC(int_sk_sendmsg_off),
 540                 [META_ID(SK_WRITE_PENDING)]     = META_FUNC(int_sk_write_pend),
 541                 [META_ID(VLAN_TAG)]             = META_FUNC(int_vlan_tag),
 542         }
 543 };
 544
 545 static inline struct meta_ops * meta_ops(struct meta_value *val)
 546 {
 547         return &__meta_ops[meta_type(val)][meta_id(val)];
 548 }
 549
 550 /**************************************************************************
 551  * Type specific operations for TCF_META_TYPE_VAR
 552  **************************************************************************/
 553
 554 static int meta_var_compare(struct meta_obj *a, struct meta_obj *b)
 555 {
 556         int r = a->len - b->len;
 557
 558         if (r == 0)
 559                 r = memcmp((void *) a->value, (void *) b->value, a->len);
 560
 561         return r;
 562 }
 563
 564 static int meta_var_change(struct meta_value *dst, struct nlattr *nla)
 565 {
 566         int len = nla_len(nla);
 567
 568         dst->val = (unsigned long)kmemdup(nla_data(nla), len, GFP_KERNEL);
 569         if (dst->val == 0UL)
 570                 return -ENOMEM;
 571         dst->len = len;
 572         return 0;
 573 }
 574
 575 static void meta_var_destroy(struct meta_value *v)
 576 {
 577         kfree((void *) v->val);
 578 }
 579
 580 static void meta_var_apply_extras(struct meta_value *v,
 581                                   struct meta_obj *dst)
 582 {
 583         int shift = v->hdr.shift;
 584
 585         if (shift && shift < dst->len)
 586                 dst->len -= shift;
 587 }
 588
 589 static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 590 {
 591         if (v->val && v->len)
 592                 NLA_PUT(skb, tlv, v->len, (void *) v->val);
 593         return 0;
 594
 595 nla_put_failure:
 596         return -1;
 597 }
 598
 599 /**************************************************************************
 600  * Type specific operations for TCF_META_TYPE_INT
 601  **************************************************************************/
 602
 603 static int meta_int_compare(struct meta_obj *a, struct meta_obj *b)
 604 {
 605         /* Let gcc optimize it, the unlikely is not really based on
 606          * some numbers but jump free code for mismatches seems
 607          * more logical. */
 608         if (unlikely(a->value == b->value))
 609                 return 0;
 610         else if (a->value < b->value)
 611                 return -1;
 612         else
 613                 return 1;
 614 }
 615
 616 static int meta_int_change(struct meta_value *dst, struct nlattr *nla)
 617 {
 618         if (nla_len(nla) >= sizeof(unsigned long)) {
 619                 dst->val = *(unsigned long *) nla_data(nla);
 620                 dst->len = sizeof(unsigned long);
 621         } else if (nla_len(nla) == sizeof(u32)) {
 622                 dst->val = nla_get_u32(nla);
 623                 dst->len = sizeof(u32);
 624         } else
 625                 return -EINVAL;
 626
 627         return 0;
 628 }
 629
 630 static void meta_int_apply_extras(struct meta_value *v,
 631                                   struct meta_obj *dst)
 632 {
 633         if (v->hdr.shift)
 634                 dst->value >>= v->hdr.shift;
 635
 636         if (v->val)
 637                 dst->value &= v->val;
 638 }
 639
 640 static int meta_int_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 641 {
 642         if (v->len == sizeof(unsigned long))
 643                 NLA_PUT(skb, tlv, sizeof(unsigned long), &v->val);
 644         else if (v->len == sizeof(u32)) {
 645                 NLA_PUT_U32(skb, tlv, v->val);
 646         }
 647
 648         return 0;
 649
 650 nla_put_failure:
 651         return -1;
 652 }
 653
 654 /**************************************************************************
 655  * Type specific operations table
 656  **************************************************************************/
 657
 658 struct meta_type_ops
 659 {
 660         void    (*destroy)(struct meta_value *);
 661         int     (*compare)(struct meta_obj *, struct meta_obj *);
 662         int     (*change)(struct meta_value *, struct nlattr *);
 663         void    (*apply_extras)(struct meta_value *, struct meta_obj *);
 664         int     (*dump)(struct sk_buff *, struct meta_value *, int);
 665 };
 666
 667 static struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX+1] = {
 668         [TCF_META_TYPE_VAR] = {
 669                 .destroy = meta_var_destroy,
 670                 .compare = meta_var_compare,
 671                 .change = meta_var_change,
 672                 .apply_extras = meta_var_apply_extras,
 673                 .dump = meta_var_dump
 674         },
 675         [TCF_META_TYPE_INT] = {
 676                 .compare = meta_int_compare,
 677                 .change = meta_int_change,
 678                 .apply_extras = meta_int_apply_extras,
 679                 .dump = meta_int_dump
 680         }
 681 };
 682
 683 static inline struct meta_type_ops * meta_type_ops(struct meta_value *v)
 684 {
 685         return &__meta_type_ops[meta_type(v)];
 686 }
 687
 688 /**************************************************************************
 689  * Core
 690  **************************************************************************/
 691
 692 static int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info,
 693                     struct meta_value *v, struct meta_obj *dst)
 694 {
 695         int err = 0;
 696
 697         if (meta_id(v) == TCF_META_ID_VALUE) {
 698                 dst->value = v->val;
 699                 dst->len = v->len;
 700                 return 0;
 701         }
 702
 703         meta_ops(v)->get(skb, info, v, dst, &err);
 704         if (err < 0)
 705                 return err;
 706
 707         if (meta_type_ops(v)->apply_extras)
 708             meta_type_ops(v)->apply_extras(v, dst);
 709
 710         return 0;
 711 }
 712
 713 static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
 714                          struct tcf_pkt_info *info)
 715 {
 716         int r;
 717         struct meta_match *meta = (struct meta_match *) m->data;
 718         struct meta_obj l_value, r_value;
 719
 720         if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 ||
 721             meta_get(skb, info, &meta->rvalue, &r_value) < 0)
 722                 return 0;
 723
 724         r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value);
 725
 726         switch (meta->lvalue.hdr.op) {
 727                 case TCF_EM_OPND_EQ:
 728                         return !r;
 729                 case TCF_EM_OPND_LT:
 730                         return r < 0;
 731                 case TCF_EM_OPND_GT:
 732                         return r > 0;
 733         }
 734
 735         return 0;
 736 }
 737
 738 static void meta_delete(struct meta_match *meta)
 739 {
 740         if (meta) {
 741                 struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
 742
 743                 if (ops && ops->destroy) {
 744                         ops->destroy(&meta->lvalue);
 745                         ops->destroy(&meta->rvalue);
 746                 }
 747         }
 748
 749         kfree(meta);
 750 }
 751
 752 static inline int meta_change_data(struct meta_value *dst, struct nlattr *nla)
 753 {
 754         if (nla) {
 755                 if (nla_len(nla) == 0)
 756                         return -EINVAL;
 757
 758                 return meta_type_ops(dst)->change(dst, nla);
 759         }
 760
 761         return 0;
 762 }
 763
 764 static inline int meta_is_supported(struct meta_value *val)
 765 {
 766         return (!meta_id(val) || meta_ops(val)->get);
 767 }
 768
 769 static const struct nla_policy meta_policy[TCA_EM_META_MAX + 1] = {
 770         [TCA_EM_META_HDR]       = { .len = sizeof(struct tcf_meta_hdr) },
 771 };
 772
 773 static int em_meta_change(struct tcf_proto *tp, void *data, int len,
 774                           struct tcf_ematch *m)
 775 {
 776         int err;
 777         struct nlattr *tb[TCA_EM_META_MAX + 1];
 778         struct tcf_meta_hdr *hdr;
 779         struct meta_match *meta = NULL;
 780
 781         err = nla_parse(tb, TCA_EM_META_MAX, data, len, meta_policy);
 782         if (err < 0)
 783                 goto errout;
 784
 785         err = -EINVAL;
 786         if (tb[TCA_EM_META_HDR] == NULL)
 787                 goto errout;
 788         hdr = nla_data(tb[TCA_EM_META_HDR]);
 789
 790         if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) ||
 791             TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX ||
 792             TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX ||
 793             TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX)
 794                 goto errout;
 795
 796         meta = kzalloc(sizeof(*meta), GFP_KERNEL);
 797         if (meta == NULL)
 798                 goto errout;
 799
 800         memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));
 801         memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right));
 802
 803         if (!meta_is_supported(&meta->lvalue) ||
 804             !meta_is_supported(&meta->rvalue)) {
 805                 err = -EOPNOTSUPP;
 806                 goto errout;
 807         }
 808
 809         if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE]) < 0 ||
 810             meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE]) < 0)
 811                 goto errout;
 812
 813         m->datalen = sizeof(*meta);
 814         m->data = (unsigned long) meta;
 815
 816         err = 0;
 817 errout:
 818         if (err && meta)
 819                 meta_delete(meta);
 820         return err;
 821 }
 822
 823 static void em_meta_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
 824 {
 825         if (m)
 826                 meta_delete((struct meta_match *) m->data);
 827 }
 828
 829 static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em)
 830 {
 831         struct meta_match *meta = (struct meta_match *) em->data;
 832         struct tcf_meta_hdr hdr;
 833         struct meta_type_ops *ops;
 834
 835         memset(&hdr, 0, sizeof(hdr));
 836         memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left));
 837         memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right));
 838
 839         NLA_PUT(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr);
 840
 841         ops = meta_type_ops(&meta->lvalue);
 842         if (ops->dump(skb, &meta->lvalue, TCA_EM_META_LVALUE) < 0 ||
 843             ops->dump(skb, &meta->rvalue, TCA_EM_META_RVALUE) < 0)
 844                 goto nla_put_failure;
 845
 846         return 0;
 847
 848 nla_put_failure:
 849         return -1;
 850 }
 851
 852 static struct tcf_ematch_ops em_meta_ops = {
 853         .kind     = TCF_EM_META,
 854         .change   = em_meta_change,
 855         .match    = em_meta_match,
 856         .destroy  = em_meta_destroy,
 857         .dump     = em_meta_dump,
 858         .owner    = THIS_MODULE,
 859         .link     = LIST_HEAD_INIT(em_meta_ops.link)
 860 };
 861
 862 static int __init init_em_meta(void)
 863 {
 864         return tcf_em_register(&em_meta_ops);
 865 }
 866
 867 static void __exit exit_em_meta(void)
 868 {
 869         tcf_em_unregister(&em_meta_ops);
 870 }
 871
 872 MODULE_LICENSE("GPL");
 873
 874 module_init(init_em_meta);
 875 module_exit(exit_em_meta);
 876
 877 MODULE_ALIAS_TCF_EMATCH(TCF_EM_META);