linux/net/sched/em_meta.c
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   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/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
  74struct meta_obj
  75{
  76        unsigned long           value;
  77        unsigned int            len;
  78};
  79
  80struct meta_value
  81{
  82        struct tcf_meta_val     hdr;
  83        unsigned long           val;
  84        unsigned int            len;
  85};
  86
  87struct meta_match
  88{
  89        struct meta_value       lvalue;
  90        struct meta_value       rvalue;
  91};
  92
  93static inline int meta_id(struct meta_value *v)
  94{
  95        return TCF_META_ID(v->hdr.kind);
  96}
  97
  98static 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
 111META_COLLECTOR(int_random)
 112{
 113        get_random_bytes(&dst->value, sizeof(dst->value));
 114}
 115
 116static 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
 124META_COLLECTOR(int_loadavg_0)
 125{
 126        dst->value = fixed_loadavg(avenrun[0]);
 127}
 128
 129META_COLLECTOR(int_loadavg_1)
 130{
 131        dst->value = fixed_loadavg(avenrun[1]);
 132}
 133
 134META_COLLECTOR(int_loadavg_2)
 135{
 136        dst->value = fixed_loadavg(avenrun[2]);
 137}
 138
 139/**************************************************************************
 140 * Device names & indices
 141 **************************************************************************/
 142
 143static 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
 152static 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
 162META_COLLECTOR(int_dev)
 163{
 164        *err = int_dev(skb->dev, dst);
 165}
 166
 167META_COLLECTOR(var_dev)
 168{
 169        *err = var_dev(skb->dev, dst);
 170}
 171
 172/**************************************************************************
 173 * skb attributes
 174 **************************************************************************/
 175
 176META_COLLECTOR(int_priority)
 177{
 178        dst->value = skb->priority;
 179}
 180
 181META_COLLECTOR(int_protocol)
 182{
 183        /* Let userspace take care of the byte ordering */
 184        dst->value = skb->protocol;
 185}
 186
 187META_COLLECTOR(int_pkttype)
 188{
 189        dst->value = skb->pkt_type;
 190}
 191
 192META_COLLECTOR(int_pktlen)
 193{
 194        dst->value = skb->len;
 195}
 196
 197META_COLLECTOR(int_datalen)
 198{
 199        dst->value = skb->data_len;
 200}
 201
 202META_COLLECTOR(int_maclen)
 203{
 204        dst->value = skb->mac_len;
 205}
 206
 207/**************************************************************************
 208 * Netfilter
 209 **************************************************************************/
 210
 211META_COLLECTOR(int_mark)
 212{
 213        dst->value = skb->mark;
 214}
 215
 216/**************************************************************************
 217 * Traffic Control
 218 **************************************************************************/
 219
 220META_COLLECTOR(int_tcindex)
 221{
 222        dst->value = skb->tc_index;
 223}
 224
 225/**************************************************************************
 226 * Routing
 227 **************************************************************************/
 228
 229META_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
 241META_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
 259META_COLLECTOR(int_sk_family)
 260{
 261        SKIP_NONLOCAL(skb);
 262        dst->value = skb->sk->sk_family;
 263}
 264
 265META_COLLECTOR(int_sk_state)
 266{
 267        SKIP_NONLOCAL(skb);
 268        dst->value = skb->sk->sk_state;
 269}
 270
 271META_COLLECTOR(int_sk_reuse)
 272{
 273        SKIP_NONLOCAL(skb);
 274        dst->value = skb->sk->sk_reuse;
 275}
 276
 277META_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
 284META_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(&init_net, skb->sk->sk_bound_dev_if);
 295                *err = var_dev(dev, dst);
 296                if (dev)
 297                        dev_put(dev);
 298         }
 299}
 300
 301META_COLLECTOR(int_sk_refcnt)
 302{
 303        SKIP_NONLOCAL(skb);
 304        dst->value = atomic_read(&skb->sk->sk_refcnt);
 305}
 306
 307META_COLLECTOR(int_sk_rcvbuf)
 308{
 309        SKIP_NONLOCAL(skb);
 310        dst->value = skb->sk->sk_rcvbuf;
 311}
 312
 313META_COLLECTOR(int_sk_shutdown)
 314{
 315        SKIP_NONLOCAL(skb);
 316        dst->value = skb->sk->sk_shutdown;
 317}
 318
 319META_COLLECTOR(int_sk_proto)
 320{
 321        SKIP_NONLOCAL(skb);
 322        dst->value = skb->sk->sk_protocol;
 323}
 324
 325META_COLLECTOR(int_sk_type)
 326{
 327        SKIP_NONLOCAL(skb);
 328        dst->value = skb->sk->sk_type;
 329}
 330
 331META_COLLECTOR(int_sk_rmem_alloc)
 332{
 333        SKIP_NONLOCAL(skb);
 334        dst->value = atomic_read(&skb->sk->sk_rmem_alloc);
 335}
 336
 337META_COLLECTOR(int_sk_wmem_alloc)
 338{
 339        SKIP_NONLOCAL(skb);
 340        dst->value = atomic_read(&skb->sk->sk_wmem_alloc);
 341}
 342
 343META_COLLECTOR(int_sk_omem_alloc)
 344{
 345        SKIP_NONLOCAL(skb);
 346        dst->value = atomic_read(&skb->sk->sk_omem_alloc);
 347}
 348
 349META_COLLECTOR(int_sk_rcv_qlen)
 350{
 351        SKIP_NONLOCAL(skb);
 352        dst->value = skb->sk->sk_receive_queue.qlen;
 353}
 354
 355META_COLLECTOR(int_sk_snd_qlen)
 356{
 357        SKIP_NONLOCAL(skb);
 358        dst->value = skb->sk->sk_write_queue.qlen;
 359}
 360
 361META_COLLECTOR(int_sk_wmem_queued)
 362{
 363        SKIP_NONLOCAL(skb);
 364        dst->value = skb->sk->sk_wmem_queued;
 365}
 366
 367META_COLLECTOR(int_sk_fwd_alloc)
 368{
 369        SKIP_NONLOCAL(skb);
 370        dst->value = skb->sk->sk_forward_alloc;
 371}
 372
 373META_COLLECTOR(int_sk_sndbuf)
 374{
 375        SKIP_NONLOCAL(skb);
 376        dst->value = skb->sk->sk_sndbuf;
 377}
 378
 379META_COLLECTOR(int_sk_alloc)
 380{
 381        SKIP_NONLOCAL(skb);
 382        dst->value = skb->sk->sk_allocation;
 383}
 384
 385META_COLLECTOR(int_sk_route_caps)
 386{
 387        SKIP_NONLOCAL(skb);
 388        dst->value = skb->sk->sk_route_caps;
 389}
 390
 391META_COLLECTOR(int_sk_hash)
 392{
 393        SKIP_NONLOCAL(skb);
 394        dst->value = skb->sk->sk_hash;
 395}
 396
 397META_COLLECTOR(int_sk_lingertime)
 398{
 399        SKIP_NONLOCAL(skb);
 400        dst->value = skb->sk->sk_lingertime / HZ;
 401}
 402
 403META_COLLECTOR(int_sk_err_qlen)
 404{
 405        SKIP_NONLOCAL(skb);
 406        dst->value = skb->sk->sk_error_queue.qlen;
 407}
 408
 409META_COLLECTOR(int_sk_ack_bl)
 410{
 411        SKIP_NONLOCAL(skb);
 412        dst->value = skb->sk->sk_ack_backlog;
 413}
 414
 415META_COLLECTOR(int_sk_max_ack_bl)
 416{
 417        SKIP_NONLOCAL(skb);
 418        dst->value = skb->sk->sk_max_ack_backlog;
 419}
 420
 421META_COLLECTOR(int_sk_prio)
 422{
 423        SKIP_NONLOCAL(skb);
 424        dst->value = skb->sk->sk_priority;
 425}
 426
 427META_COLLECTOR(int_sk_rcvlowat)
 428{
 429        SKIP_NONLOCAL(skb);
 430        dst->value = skb->sk->sk_rcvlowat;
 431}
 432
 433META_COLLECTOR(int_sk_rcvtimeo)
 434{
 435        SKIP_NONLOCAL(skb);
 436        dst->value = skb->sk->sk_rcvtimeo / HZ;
 437}
 438
 439META_COLLECTOR(int_sk_sndtimeo)
 440{
 441        SKIP_NONLOCAL(skb);
 442        dst->value = skb->sk->sk_sndtimeo / HZ;
 443}
 444
 445META_COLLECTOR(int_sk_sendmsg_off)
 446{
 447        SKIP_NONLOCAL(skb);
 448        dst->value = skb->sk->sk_sndmsg_off;
 449}
 450
 451META_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
 461struct 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. */
 472static 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
 526static 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
 535static 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
 545static 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
 556static void meta_var_destroy(struct meta_value *v)
 557{
 558        kfree((void *) v->val);
 559}
 560
 561static 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
 570static 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
 576rtattr_failure:
 577        return -1;
 578}
 579
 580/**************************************************************************
 581 * Type specific operations for TCF_META_TYPE_INT
 582 **************************************************************************/
 583
 584static 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
 597static 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
 611static 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
 621static 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
 632rtattr_failure:
 633        return -1;
 634}
 635
 636/**************************************************************************
 637 * Type specific operations table
 638 **************************************************************************/
 639
 640struct 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
 649static 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
 665static 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
 674static 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
 695static 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
 720static 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
 732static 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
 744static inline int meta_is_supported(struct meta_value *val)
 745{
 746        return (!meta_id(val) || meta_ops(val)->get);
 747}
 748
 749static 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;
 792errout:
 793        if (err && meta)
 794                meta_delete(meta);
 795        return err;
 796}
 797
 798static 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
 804static 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
 823rtattr_failure:
 824        return -1;
 825}
 826
 827static 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
 837static int __init init_em_meta(void)
 838{
 839        return tcf_em_register(&em_meta_ops);
 840}
 841
 842static void __exit exit_em_meta(void)
 843{
 844        tcf_em_unregister(&em_meta_ops);
 845}
 846
 847MODULE_LICENSE("GPL");
 848
 849module_init(init_em_meta);
 850module_exit(exit_em_meta);
 851
 852MODULE_ALIAS_TCF_EMATCH(TCF_EM_META);
 853