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 subsytem 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/tc_ematch/tc_em_meta.h>
  69 #include <net/dst.h>
  70 #include <net/route.h>
  71 #include <net/pkt_cls.h>
  72 #include <net/sock.h>
  73
  74 struct meta_obj
  75 {
  76         unsigned long           value;
  77         unsigned int            len;
  78 };
  79
  80 struct meta_value
  81 {
  82         struct tcf_meta_val     hdr;
  83         unsigned long           val;
  84         unsigned int            len;
  85 };
  86
  87 struct meta_match
  88 {
  89         struct meta_value       lvalue;
  90         struct meta_value       rvalue;
  91 };
  92
  93 static inline int meta_id(struct meta_value *v)
  94 {
  95         return TCF_META_ID(v->hdr.kind);
  96 }
  97
  98 static inline int meta_type(struct meta_value *v)
  99 {
 100         return TCF_META_TYPE(v->hdr.kind);
 101 }
 102
 103 #define META_COLLECTOR(FUNC) static void meta_##FUNC(struct sk_buff *skb, \
 104         struct tcf_pkt_info *info, struct meta_value *v, \
 105         struct meta_obj *dst, int *err)
 106
 107 /**************************************************************************
 108  * System status & misc
 109  **************************************************************************/
 110
 111 META_COLLECTOR(int_random)
 112 {
 113         get_random_bytes(&dst->value, sizeof(dst->value));
 114 }
 115
 116 static inline unsigned long fixed_loadavg(int load)
 117 {
 118         int rnd_load = load + (FIXED_1/200);
 119         int rnd_frac = ((rnd_load & (FIXED_1-1)) * 100) >> FSHIFT;
 120
 121         return ((rnd_load >> FSHIFT) * 100) + rnd_frac;
 122 }
 123
 124 META_COLLECTOR(int_loadavg_0)
 125 {
 126         dst->value = fixed_loadavg(avenrun[0]);
 127 }
 128
 129 META_COLLECTOR(int_loadavg_1)
 130 {
 131         dst->value = fixed_loadavg(avenrun[1]);
 132 }
 133
 134 META_COLLECTOR(int_loadavg_2)
 135 {
 136         dst->value = fixed_loadavg(avenrun[2]);
 137 }
 138
 139 /**************************************************************************
 140  * Device names & indices
 141  **************************************************************************/
 142
 143 static inline int int_dev(struct net_device *dev, struct meta_obj *dst)
 144 {
 145         if (unlikely(dev == NULL))
 146                 return -1;
 147
 148         dst->value = dev->ifindex;
 149         return 0;
 150 }
 151
 152 static inline int var_dev(struct net_device *dev, struct meta_obj *dst)
 153 {
 154         if (unlikely(dev == NULL))
 155                 return -1;
 156
 157         dst->value = (unsigned long) dev->name;
 158         dst->len = strlen(dev->name);
 159         return 0;
 160 }
 161
 162 META_COLLECTOR(int_dev)
 163 {
 164         *err = int_dev(skb->dev, dst);
 165 }
 166
 167 META_COLLECTOR(var_dev)
 168 {
 169         *err = var_dev(skb->dev, dst);
 170 }
 171
 172 /**************************************************************************
 173  * skb attributes
 174  **************************************************************************/
 175
 176 META_COLLECTOR(int_priority)
 177 {
 178         dst->value = skb->priority;
 179 }
 180
 181 META_COLLECTOR(int_protocol)
 182 {
 183         /* Let userspace take care of the byte ordering */
 184         dst->value = skb->protocol;
 185 }
 186
 187 META_COLLECTOR(int_pkttype)
 188 {
 189         dst->value = skb->pkt_type;
 190 }
 191
 192 META_COLLECTOR(int_pktlen)
 193 {
 194         dst->value = skb->len;
 195 }
 196
 197 META_COLLECTOR(int_datalen)
 198 {
 199         dst->value = skb->data_len;
 200 }
 201
 202 META_COLLECTOR(int_maclen)
 203 {
 204         dst->value = skb->mac_len;
 205 }
 206
 207 /**************************************************************************
 208  * Netfilter
 209  **************************************************************************/
 210
 211 META_COLLECTOR(int_mark)
 212 {
 213         dst->value = skb->mark;
 214 }
 215
 216 /**************************************************************************
 217  * Traffic Control
 218  **************************************************************************/
 219
 220 META_COLLECTOR(int_tcindex)
 221 {
 222         dst->value = skb->tc_index;
 223 }
 224
 225 /**************************************************************************
 226  * Routing
 227  **************************************************************************/
 228
 229 META_COLLECTOR(int_rtclassid)
 230 {
 231         if (unlikely(skb->dst == NULL))
 232                 *err = -1;
 233         else
 234 #ifdef CONFIG_NET_CLS_ROUTE
 235                 dst->value = skb->dst->tclassid;
 236 #else
 237                 dst->value = 0;
 238 #endif
 239 }
 240
 241 META_COLLECTOR(int_rtiif)
 242 {
 243         if (unlikely(skb->dst == NULL))
 244                 *err = -1;
 245         else
 246                 dst->value = ((struct rtable*) skb->dst)->fl.iif;
 247 }
 248
 249 /**************************************************************************
 250  * Socket Attributes
 251  **************************************************************************/
 252
 253 #define SKIP_NONLOCAL(skb)                      \
 254         if (unlikely(skb->sk == NULL)) {        \
 255                 *err = -1;                      \
 256                 return;                         \
 257         }
 258
 259 META_COLLECTOR(int_sk_family)
 260 {
 261         SKIP_NONLOCAL(skb);
 262         dst->value = skb->sk->sk_family;
 263 }
 264
 265 META_COLLECTOR(int_sk_state)
 266 {
 267         SKIP_NONLOCAL(skb);
 268         dst->value = skb->sk->sk_state;
 269 }
 270
 271 META_COLLECTOR(int_sk_reuse)
 272 {
 273         SKIP_NONLOCAL(skb);
 274         dst->value = skb->sk->sk_reuse;
 275 }
 276
 277 META_COLLECTOR(int_sk_bound_if)
 278 {
 279         SKIP_NONLOCAL(skb);
 280         /* No error if bound_dev_if is 0, legal userspace check */
 281         dst->value = skb->sk->sk_bound_dev_if;
 282 }
 283
 284 META_COLLECTOR(var_sk_bound_if)
 285 {
 286         SKIP_NONLOCAL(skb);
 287
 288          if (skb->sk->sk_bound_dev_if == 0) {
 289                 dst->value = (unsigned long) "any";
 290                 dst->len = 3;
 291          } else  {
 292                 struct net_device *dev;
 293
 294                 dev = dev_get_by_index(skb->sk->sk_bound_dev_if);
 295                 *err = var_dev(dev, dst);
 296                 if (dev)
 297                         dev_put(dev);
 298          }
 299 }
 300
 301 META_COLLECTOR(int_sk_refcnt)
 302 {
 303         SKIP_NONLOCAL(skb);
 304         dst->value = atomic_read(&skb->sk->sk_refcnt);
 305 }
 306
 307 META_COLLECTOR(int_sk_rcvbuf)
 308 {
 309         SKIP_NONLOCAL(skb);
 310         dst->value = skb->sk->sk_rcvbuf;
 311 }
 312
 313 META_COLLECTOR(int_sk_shutdown)
 314 {
 315         SKIP_NONLOCAL(skb);
 316         dst->value = skb->sk->sk_shutdown;
 317 }
 318
 319 META_COLLECTOR(int_sk_proto)
 320 {
 321         SKIP_NONLOCAL(skb);
 322         dst->value = skb->sk->sk_protocol;
 323 }
 324
 325 META_COLLECTOR(int_sk_type)
 326 {
 327         SKIP_NONLOCAL(skb);
 328         dst->value = skb->sk->sk_type;
 329 }
 330
 331 META_COLLECTOR(int_sk_rmem_alloc)
 332 {
 333         SKIP_NONLOCAL(skb);
 334         dst->value = atomic_read(&skb->sk->sk_rmem_alloc);
 335 }
 336
 337 META_COLLECTOR(int_sk_wmem_alloc)
 338 {
 339         SKIP_NONLOCAL(skb);
 340         dst->value = atomic_read(&skb->sk->sk_wmem_alloc);
 341 }
 342
 343 META_COLLECTOR(int_sk_omem_alloc)
 344 {
 345         SKIP_NONLOCAL(skb);
 346         dst->value = atomic_read(&skb->sk->sk_omem_alloc);
 347 }
 348
 349 META_COLLECTOR(int_sk_rcv_qlen)
 350 {
 351         SKIP_NONLOCAL(skb);
 352         dst->value = skb->sk->sk_receive_queue.qlen;
 353 }
 354
 355 META_COLLECTOR(int_sk_snd_qlen)
 356 {
 357         SKIP_NONLOCAL(skb);
 358         dst->value = skb->sk->sk_write_queue.qlen;
 359 }
 360
 361 META_COLLECTOR(int_sk_wmem_queued)
 362 {
 363         SKIP_NONLOCAL(skb);
 364         dst->value = skb->sk->sk_wmem_queued;
 365 }
 366
 367 META_COLLECTOR(int_sk_fwd_alloc)
 368 {
 369         SKIP_NONLOCAL(skb);
 370         dst->value = skb->sk->sk_forward_alloc;
 371 }
 372
 373 META_COLLECTOR(int_sk_sndbuf)
 374 {
 375         SKIP_NONLOCAL(skb);
 376         dst->value = skb->sk->sk_sndbuf;
 377 }
 378
 379 META_COLLECTOR(int_sk_alloc)
 380 {
 381         SKIP_NONLOCAL(skb);
 382         dst->value = skb->sk->sk_allocation;
 383 }
 384
 385 META_COLLECTOR(int_sk_route_caps)
 386 {
 387         SKIP_NONLOCAL(skb);
 388         dst->value = skb->sk->sk_route_caps;
 389 }
 390
 391 META_COLLECTOR(int_sk_hash)
 392 {
 393         SKIP_NONLOCAL(skb);
 394         dst->value = skb->sk->sk_hash;
 395 }
 396
 397 META_COLLECTOR(int_sk_lingertime)
 398 {
 399         SKIP_NONLOCAL(skb);
 400         dst->value = skb->sk->sk_lingertime / HZ;
 401 }
 402
 403 META_COLLECTOR(int_sk_err_qlen)
 404 {
 405         SKIP_NONLOCAL(skb);
 406         dst->value = skb->sk->sk_error_queue.qlen;
 407 }
 408
 409 META_COLLECTOR(int_sk_ack_bl)
 410 {
 411         SKIP_NONLOCAL(skb);
 412         dst->value = skb->sk->sk_ack_backlog;
 413 }
 414
 415 META_COLLECTOR(int_sk_max_ack_bl)
 416 {
 417         SKIP_NONLOCAL(skb);
 418         dst->value = skb->sk->sk_max_ack_backlog;
 419 }
 420
 421 META_COLLECTOR(int_sk_prio)
 422 {
 423         SKIP_NONLOCAL(skb);
 424         dst->value = skb->sk->sk_priority;
 425 }
 426
 427 META_COLLECTOR(int_sk_rcvlowat)
 428 {
 429         SKIP_NONLOCAL(skb);
 430         dst->value = skb->sk->sk_rcvlowat;
 431 }
 432
 433 META_COLLECTOR(int_sk_rcvtimeo)
 434 {
 435         SKIP_NONLOCAL(skb);
 436         dst->value = skb->sk->sk_rcvtimeo / HZ;
 437 }
 438
 439 META_COLLECTOR(int_sk_sndtimeo)
 440 {
 441         SKIP_NONLOCAL(skb);
 442         dst->value = skb->sk->sk_sndtimeo / HZ;
 443 }
 444
 445 META_COLLECTOR(int_sk_sendmsg_off)
 446 {
 447         SKIP_NONLOCAL(skb);
 448         dst->value = skb->sk->sk_sndmsg_off;
 449 }
 450
 451 META_COLLECTOR(int_sk_write_pend)
 452 {
 453         SKIP_NONLOCAL(skb);
 454         dst->value = skb->sk->sk_write_pending;
 455 }
 456
 457 /**************************************************************************
 458  * Meta value collectors assignment table
 459  **************************************************************************/
 460
 461 struct meta_ops
 462 {
 463         void            (*get)(struct sk_buff *, struct tcf_pkt_info *,
 464                                struct meta_value *, struct meta_obj *, int *);
 465 };
 466
 467 #define META_ID(name) TCF_META_ID_##name
 468 #define META_FUNC(name) { .get = meta_##name }
 469
 470 /* Meta value operations table listing all meta value collectors and
 471  * assigns them to a type and meta id. */
 472 static struct meta_ops __meta_ops[TCF_META_TYPE_MAX+1][TCF_META_ID_MAX+1] = {
 473         [TCF_META_TYPE_VAR] = {
 474                 [META_ID(DEV)]                  = META_FUNC(var_dev),
 475                 [META_ID(SK_BOUND_IF)]          = META_FUNC(var_sk_bound_if),
 476         },
 477         [TCF_META_TYPE_INT] = {
 478                 [META_ID(RANDOM)]               = META_FUNC(int_random),
 479                 [META_ID(LOADAVG_0)]            = META_FUNC(int_loadavg_0),
 480                 [META_ID(LOADAVG_1)]            = META_FUNC(int_loadavg_1),
 481                 [META_ID(LOADAVG_2)]            = META_FUNC(int_loadavg_2),
 482                 [META_ID(DEV)]                  = META_FUNC(int_dev),
 483                 [META_ID(PRIORITY)]             = META_FUNC(int_priority),
 484                 [META_ID(PROTOCOL)]             = META_FUNC(int_protocol),
 485                 [META_ID(PKTTYPE)]              = META_FUNC(int_pkttype),
 486                 [META_ID(PKTLEN)]               = META_FUNC(int_pktlen),
 487                 [META_ID(DATALEN)]              = META_FUNC(int_datalen),
 488                 [META_ID(MACLEN)]               = META_FUNC(int_maclen),
 489                 [META_ID(NFMARK)]               = META_FUNC(int_mark),
 490                 [META_ID(TCINDEX)]              = META_FUNC(int_tcindex),
 491                 [META_ID(RTCLASSID)]            = META_FUNC(int_rtclassid),
 492                 [META_ID(RTIIF)]                = META_FUNC(int_rtiif),
 493                 [META_ID(SK_FAMILY)]            = META_FUNC(int_sk_family),
 494                 [META_ID(SK_STATE)]             = META_FUNC(int_sk_state),
 495                 [META_ID(SK_REUSE)]             = META_FUNC(int_sk_reuse),
 496                 [META_ID(SK_BOUND_IF)]          = META_FUNC(int_sk_bound_if),
 497                 [META_ID(SK_REFCNT)]            = META_FUNC(int_sk_refcnt),
 498                 [META_ID(SK_RCVBUF)]            = META_FUNC(int_sk_rcvbuf),
 499                 [META_ID(SK_SNDBUF)]            = META_FUNC(int_sk_sndbuf),
 500                 [META_ID(SK_SHUTDOWN)]          = META_FUNC(int_sk_shutdown),
 501                 [META_ID(SK_PROTO)]             = META_FUNC(int_sk_proto),
 502                 [META_ID(SK_TYPE)]              = META_FUNC(int_sk_type),
 503                 [META_ID(SK_RMEM_ALLOC)]        = META_FUNC(int_sk_rmem_alloc),
 504                 [META_ID(SK_WMEM_ALLOC)]        = META_FUNC(int_sk_wmem_alloc),
 505                 [META_ID(SK_OMEM_ALLOC)]        = META_FUNC(int_sk_omem_alloc),
 506                 [META_ID(SK_WMEM_QUEUED)]       = META_FUNC(int_sk_wmem_queued),
 507                 [META_ID(SK_RCV_QLEN)]          = META_FUNC(int_sk_rcv_qlen),
 508                 [META_ID(SK_SND_QLEN)]          = META_FUNC(int_sk_snd_qlen),
 509                 [META_ID(SK_ERR_QLEN)]          = META_FUNC(int_sk_err_qlen),
 510                 [META_ID(SK_FORWARD_ALLOCS)]    = META_FUNC(int_sk_fwd_alloc),
 511                 [META_ID(SK_ALLOCS)]            = META_FUNC(int_sk_alloc),
 512                 [META_ID(SK_ROUTE_CAPS)]        = META_FUNC(int_sk_route_caps),
 513                 [META_ID(SK_HASH)]              = META_FUNC(int_sk_hash),
 514                 [META_ID(SK_LINGERTIME)]        = META_FUNC(int_sk_lingertime),
 515                 [META_ID(SK_ACK_BACKLOG)]       = META_FUNC(int_sk_ack_bl),
 516                 [META_ID(SK_MAX_ACK_BACKLOG)]   = META_FUNC(int_sk_max_ack_bl),
 517                 [META_ID(SK_PRIO)]              = META_FUNC(int_sk_prio),
 518                 [META_ID(SK_RCVLOWAT)]          = META_FUNC(int_sk_rcvlowat),
 519                 [META_ID(SK_RCVTIMEO)]          = META_FUNC(int_sk_rcvtimeo),
 520                 [META_ID(SK_SNDTIMEO)]          = META_FUNC(int_sk_sndtimeo),
 521                 [META_ID(SK_SENDMSG_OFF)]       = META_FUNC(int_sk_sendmsg_off),
 522                 [META_ID(SK_WRITE_PENDING)]     = META_FUNC(int_sk_write_pend),
 523         }
 524 };
 525
 526 static inline struct meta_ops * meta_ops(struct meta_value *val)
 527 {
 528         return &__meta_ops[meta_type(val)][meta_id(val)];
 529 }
 530
 531 /**************************************************************************
 532  * Type specific operations for TCF_META_TYPE_VAR
 533  **************************************************************************/
 534
 535 static int meta_var_compare(struct meta_obj *a, struct meta_obj *b)
 536 {
 537         int r = a->len - b->len;
 538
 539         if (r == 0)
 540                 r = memcmp((void *) a->value, (void *) b->value, a->len);
 541
 542         return r;
 543 }
 544
 545 static int meta_var_change(struct meta_value *dst, struct rtattr *rta)
 546 {
 547         int len = RTA_PAYLOAD(rta);
 548
 549         dst->val = (unsigned long)kmemdup(RTA_DATA(rta), len, GFP_KERNEL);
 550         if (dst->val == 0UL)
 551                 return -ENOMEM;
 552         dst->len = len;
 553         return 0;
 554 }
 555
 556 static void meta_var_destroy(struct meta_value *v)
 557 {
 558         kfree((void *) v->val);
 559 }
 560
 561 static void meta_var_apply_extras(struct meta_value *v,
 562                                   struct meta_obj *dst)
 563 {
 564         int shift = v->hdr.shift;
 565
 566         if (shift && shift < dst->len)
 567                 dst->len -= shift;
 568 }
 569
 570 static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 571 {
 572         if (v->val && v->len)
 573                 RTA_PUT(skb, tlv, v->len, (void *) v->val);
 574         return 0;
 575
 576 rtattr_failure:
 577         return -1;
 578 }
 579
 580 /**************************************************************************
 581  * Type specific operations for TCF_META_TYPE_INT
 582  **************************************************************************/
 583
 584 static int meta_int_compare(struct meta_obj *a, struct meta_obj *b)
 585 {
 586         /* Let gcc optimize it, the unlikely is not really based on
 587          * some numbers but jump free code for mismatches seems
 588          * more logical. */
 589         if (unlikely(a->value == b->value))
 590                 return 0;
 591         else if (a->value < b->value)
 592                 return -1;
 593         else
 594                 return 1;
 595 }
 596
 597 static int meta_int_change(struct meta_value *dst, struct rtattr *rta)
 598 {
 599         if (RTA_PAYLOAD(rta) >= sizeof(unsigned long)) {
 600                 dst->val = *(unsigned long *) RTA_DATA(rta);
 601                 dst->len = sizeof(unsigned long);
 602         } else if (RTA_PAYLOAD(rta) == sizeof(u32)) {
 603                 dst->val = *(u32 *) RTA_DATA(rta);
 604                 dst->len = sizeof(u32);
 605         } else
 606                 return -EINVAL;
 607
 608         return 0;
 609 }
 610
 611 static void meta_int_apply_extras(struct meta_value *v,
 612                                   struct meta_obj *dst)
 613 {
 614         if (v->hdr.shift)
 615                 dst->value >>= v->hdr.shift;
 616
 617         if (v->val)
 618                 dst->value &= v->val;
 619 }
 620
 621 static int meta_int_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 622 {
 623         if (v->len == sizeof(unsigned long))
 624                 RTA_PUT(skb, tlv, sizeof(unsigned long), &v->val);
 625         else if (v->len == sizeof(u32)) {
 626                 u32 d = v->val;
 627                 RTA_PUT(skb, tlv, sizeof(d), &d);
 628         }
 629
 630         return 0;
 631
 632 rtattr_failure:
 633         return -1;
 634 }
 635
 636 /**************************************************************************
 637  * Type specific operations table
 638  **************************************************************************/
 639
 640 struct meta_type_ops
 641 {
 642         void    (*destroy)(struct meta_value *);
 643         int     (*compare)(struct meta_obj *, struct meta_obj *);
 644         int     (*change)(struct meta_value *, struct rtattr *);
 645         void    (*apply_extras)(struct meta_value *, struct meta_obj *);
 646         int     (*dump)(struct sk_buff *, struct meta_value *, int);
 647 };
 648
 649 static struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX+1] = {
 650         [TCF_META_TYPE_VAR] = {
 651                 .destroy = meta_var_destroy,
 652                 .compare = meta_var_compare,
 653                 .change = meta_var_change,
 654                 .apply_extras = meta_var_apply_extras,
 655                 .dump = meta_var_dump
 656         },
 657         [TCF_META_TYPE_INT] = {
 658                 .compare = meta_int_compare,
 659                 .change = meta_int_change,
 660                 .apply_extras = meta_int_apply_extras,
 661                 .dump = meta_int_dump
 662         }
 663 };
 664
 665 static inline struct meta_type_ops * meta_type_ops(struct meta_value *v)
 666 {
 667         return &__meta_type_ops[meta_type(v)];
 668 }
 669
 670 /**************************************************************************
 671  * Core
 672  **************************************************************************/
 673
 674 static inline int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info,
 675                            struct meta_value *v, struct meta_obj *dst)
 676 {
 677         int err = 0;
 678
 679         if (meta_id(v) == TCF_META_ID_VALUE) {
 680                 dst->value = v->val;
 681                 dst->len = v->len;
 682                 return 0;
 683         }
 684
 685         meta_ops(v)->get(skb, info, v, dst, &err);
 686         if (err < 0)
 687                 return err;
 688
 689         if (meta_type_ops(v)->apply_extras)
 690             meta_type_ops(v)->apply_extras(v, dst);
 691
 692         return 0;
 693 }
 694
 695 static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
 696                          struct tcf_pkt_info *info)
 697 {
 698         int r;
 699         struct meta_match *meta = (struct meta_match *) m->data;
 700         struct meta_obj l_value, r_value;
 701
 702         if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 ||
 703             meta_get(skb, info, &meta->rvalue, &r_value) < 0)
 704                 return 0;
 705
 706         r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value);
 707
 708         switch (meta->lvalue.hdr.op) {
 709                 case TCF_EM_OPND_EQ:
 710                         return !r;
 711                 case TCF_EM_OPND_LT:
 712                         return r < 0;
 713                 case TCF_EM_OPND_GT:
 714                         return r > 0;
 715         }
 716
 717         return 0;
 718 }
 719
 720 static inline void meta_delete(struct meta_match *meta)
 721 {
 722         struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
 723
 724         if (ops && ops->destroy) {
 725                 ops->destroy(&meta->lvalue);
 726                 ops->destroy(&meta->rvalue);
 727         }
 728
 729         kfree(meta);
 730 }
 731
 732 static inline int meta_change_data(struct meta_value *dst, struct rtattr *rta)
 733 {
 734         if (rta) {
 735                 if (RTA_PAYLOAD(rta) == 0)
 736                         return -EINVAL;
 737
 738                 return meta_type_ops(dst)->change(dst, rta);
 739         }
 740
 741         return 0;
 742 }
 743
 744 static inline int meta_is_supported(struct meta_value *val)
 745 {
 746         return (!meta_id(val) || meta_ops(val)->get);
 747 }
 748
 749 static int em_meta_change(struct tcf_proto *tp, void *data, int len,
 750                           struct tcf_ematch *m)
 751 {
 752         int err = -EINVAL;
 753         struct rtattr *tb[TCA_EM_META_MAX];
 754         struct tcf_meta_hdr *hdr;
 755         struct meta_match *meta = NULL;
 756
 757         if (rtattr_parse(tb, TCA_EM_META_MAX, data, len) < 0)
 758                 goto errout;
 759
 760         if (tb[TCA_EM_META_HDR-1] == NULL ||
 761             RTA_PAYLOAD(tb[TCA_EM_META_HDR-1]) < sizeof(*hdr))
 762                 goto errout;
 763         hdr = RTA_DATA(tb[TCA_EM_META_HDR-1]);
 764
 765         if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) ||
 766             TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX ||
 767             TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX ||
 768             TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX)
 769                 goto errout;
 770
 771         meta = kzalloc(sizeof(*meta), GFP_KERNEL);
 772         if (meta == NULL)
 773                 goto errout;
 774
 775         memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));
 776         memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right));
 777
 778         if (!meta_is_supported(&meta->lvalue) ||
 779             !meta_is_supported(&meta->rvalue)) {
 780                 err = -EOPNOTSUPP;
 781                 goto errout;
 782         }
 783
 784         if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE-1]) < 0 ||
 785             meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE-1]) < 0)
 786                 goto errout;
 787
 788         m->datalen = sizeof(*meta);
 789         m->data = (unsigned long) meta;
 790
 791         err = 0;
 792 errout:
 793         if (err && meta)
 794                 meta_delete(meta);
 795         return err;
 796 }
 797
 798 static void em_meta_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
 799 {
 800         if (m)
 801                 meta_delete((struct meta_match *) m->data);
 802 }
 803
 804 static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em)
 805 {
 806         struct meta_match *meta = (struct meta_match *) em->data;
 807         struct tcf_meta_hdr hdr;
 808         struct meta_type_ops *ops;
 809
 810         memset(&hdr, 0, sizeof(hdr));
 811         memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left));
 812         memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right));
 813
 814         RTA_PUT(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr);
 815
 816         ops = meta_type_ops(&meta->lvalue);
 817         if (ops->dump(skb, &meta->lvalue, TCA_EM_META_LVALUE) < 0 ||
 818             ops->dump(skb, &meta->rvalue, TCA_EM_META_RVALUE) < 0)
 819                 goto rtattr_failure;
 820
 821         return 0;
 822
 823 rtattr_failure:
 824         return -1;
 825 }
 826
 827 static struct tcf_ematch_ops em_meta_ops = {
 828         .kind     = TCF_EM_META,
 829         .change   = em_meta_change,
 830         .match    = em_meta_match,
 831         .destroy  = em_meta_destroy,
 832         .dump     = em_meta_dump,
 833         .owner    = THIS_MODULE,
 834         .link     = LIST_HEAD_INIT(em_meta_ops.link)
 835 };
 836
 837 static int __init init_em_meta(void)
 838 {
 839         return tcf_em_register(&em_meta_ops);
 840 }
 841
 842 static void __exit exit_em_meta(void)
 843 {
 844         tcf_em_unregister(&em_meta_ops);
 845 }
 846
 847 MODULE_LICENSE("GPL");
 848
 849 module_init(init_em_meta);
 850 module_exit(exit_em_meta);