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 *      Additionally, type dependent modifiers such as shift operators
  51 *      or mask may be applied to extend the functionaliy. As of now,
  52 *      the variable length type supports shifting the byte string to
  53 *      the right, eating up any number of octets and thus supporting
  54 *      wildcard interface name comparisons such as "ppp%" matching
  55 *      ppp0..9.
  56 *
  57 *      NOTE: Certain meta values depend on other subsystems and are
  58 *            only available if that subsystem is enabled in the kernel.
  59 */
  60
  61#include <linux/slab.h>
  62#include <linux/module.h>
  63#include <linux/types.h>
  64#include <linux/kernel.h>
  65#include <linux/sched.h>
  66#include <linux/string.h>
  67#include <linux/skbuff.h>
  68#include <linux/random.h>
  69#include <linux/if_vlan.h>
  70#include <linux/tc_ematch/tc_em_meta.h>
  71#include <net/dst.h>
  72#include <net/route.h>
  73#include <net/pkt_cls.h>
  74#include <net/sock.h>
  75
  76struct meta_obj {
  77        unsigned long           value;
  78        unsigned int            len;
  79};
  80
  81struct meta_value {
  82        struct tcf_meta_val     hdr;
  83        unsigned long           val;
  84        unsigned int            len;
  85};
  86
  87struct meta_match {
  88        struct meta_value       lvalue;
  89        struct meta_value       rvalue;
  90};
  91
  92static inline int meta_id(struct meta_value *v)
  93{
  94        return TCF_META_ID(v->hdr.kind);
  95}
  96
  97static inline int meta_type(struct meta_value *v)
  98{
  99        return TCF_META_TYPE(v->hdr.kind);
 100}
 101
 102#define META_COLLECTOR(FUNC) static void meta_##FUNC(struct sk_buff *skb, \
 103        struct tcf_pkt_info *info, struct meta_value *v, \
 104        struct meta_obj *dst, int *err)
 105
 106/**************************************************************************
 107 * System status & misc
 108 **************************************************************************/
 109
 110META_COLLECTOR(int_random)
 111{
 112        get_random_bytes(&dst->value, sizeof(dst->value));
 113}
 114
 115static inline unsigned long fixed_loadavg(int load)
 116{
 117        int rnd_load = load + (FIXED_1/200);
 118        int rnd_frac = ((rnd_load & (FIXED_1-1)) * 100) >> FSHIFT;
 119
 120        return ((rnd_load >> FSHIFT) * 100) + rnd_frac;
 121}
 122
 123META_COLLECTOR(int_loadavg_0)
 124{
 125        dst->value = fixed_loadavg(avenrun[0]);
 126}
 127
 128META_COLLECTOR(int_loadavg_1)
 129{
 130        dst->value = fixed_loadavg(avenrun[1]);
 131}
 132
 133META_COLLECTOR(int_loadavg_2)
 134{
 135        dst->value = fixed_loadavg(avenrun[2]);
 136}
 137
 138/**************************************************************************
 139 * Device names & indices
 140 **************************************************************************/
 141
 142static inline int int_dev(struct net_device *dev, struct meta_obj *dst)
 143{
 144        if (unlikely(dev == NULL))
 145                return -1;
 146
 147        dst->value = dev->ifindex;
 148        return 0;
 149}
 150
 151static inline int var_dev(struct net_device *dev, struct meta_obj *dst)
 152{
 153        if (unlikely(dev == NULL))
 154                return -1;
 155
 156        dst->value = (unsigned long) dev->name;
 157        dst->len = strlen(dev->name);
 158        return 0;
 159}
 160
 161META_COLLECTOR(int_dev)
 162{
 163        *err = int_dev(skb->dev, dst);
 164}
 165
 166META_COLLECTOR(var_dev)
 167{
 168        *err = var_dev(skb->dev, dst);
 169}
 170
 171/**************************************************************************
 172 * vlan tag
 173 **************************************************************************/
 174
 175META_COLLECTOR(int_vlan_tag)
 176{
 177        unsigned short tag;
 178
 179        tag = vlan_tx_tag_get(skb);
 180        if (!tag && __vlan_get_tag(skb, &tag))
 181                *err = -1;
 182        else
 183                dst->value = tag;
 184}
 185
 186
 187
 188/**************************************************************************
 189 * skb attributes
 190 **************************************************************************/
 191
 192META_COLLECTOR(int_priority)
 193{
 194        dst->value = skb->priority;
 195}
 196
 197META_COLLECTOR(int_protocol)
 198{
 199        /* Let userspace take care of the byte ordering */
 200        dst->value = skb->protocol;
 201}
 202
 203META_COLLECTOR(int_pkttype)
 204{
 205        dst->value = skb->pkt_type;
 206}
 207
 208META_COLLECTOR(int_pktlen)
 209{
 210        dst->value = skb->len;
 211}
 212
 213META_COLLECTOR(int_datalen)
 214{
 215        dst->value = skb->data_len;
 216}
 217
 218META_COLLECTOR(int_maclen)
 219{
 220        dst->value = skb->mac_len;
 221}
 222
 223META_COLLECTOR(int_rxhash)
 224{
 225        dst->value = skb_get_rxhash(skb);
 226}
 227
 228/**************************************************************************
 229 * Netfilter
 230 **************************************************************************/
 231
 232META_COLLECTOR(int_mark)
 233{
 234        dst->value = skb->mark;
 235}
 236
 237/**************************************************************************
 238 * Traffic Control
 239 **************************************************************************/
 240
 241META_COLLECTOR(int_tcindex)
 242{
 243        dst->value = skb->tc_index;
 244}
 245
 246/**************************************************************************
 247 * Routing
 248 **************************************************************************/
 249
 250META_COLLECTOR(int_rtclassid)
 251{
 252        if (unlikely(skb_dst(skb) == NULL))
 253                *err = -1;
 254        else
 255#ifdef CONFIG_IP_ROUTE_CLASSID
 256                dst->value = skb_dst(skb)->tclassid;
 257#else
 258                dst->value = 0;
 259#endif
 260}
 261
 262META_COLLECTOR(int_rtiif)
 263{
 264        if (unlikely(skb_rtable(skb) == NULL))
 265                *err = -1;
 266        else
 267                dst->value = inet_iif(skb);
 268}
 269
 270/**************************************************************************
 271 * Socket Attributes
 272 **************************************************************************/
 273
 274#define SKIP_NONLOCAL(skb)                      \
 275        if (unlikely(skb->sk == NULL)) {        \
 276                *err = -1;                      \
 277                return;                         \
 278        }
 279
 280META_COLLECTOR(int_sk_family)
 281{
 282        SKIP_NONLOCAL(skb);
 283        dst->value = skb->sk->sk_family;
 284}
 285
 286META_COLLECTOR(int_sk_state)
 287{
 288        SKIP_NONLOCAL(skb);
 289        dst->value = skb->sk->sk_state;
 290}
 291
 292META_COLLECTOR(int_sk_reuse)
 293{
 294        SKIP_NONLOCAL(skb);
 295        dst->value = skb->sk->sk_reuse;
 296}
 297
 298META_COLLECTOR(int_sk_bound_if)
 299{
 300        SKIP_NONLOCAL(skb);
 301        /* No error if bound_dev_if is 0, legal userspace check */
 302        dst->value = skb->sk->sk_bound_dev_if;
 303}
 304
 305META_COLLECTOR(var_sk_bound_if)
 306{
 307        SKIP_NONLOCAL(skb);
 308
 309        if (skb->sk->sk_bound_dev_if == 0) {
 310                dst->value = (unsigned long) "any";
 311                dst->len = 3;
 312        } else {
 313                struct net_device *dev;
 314
 315                rcu_read_lock();
 316                dev = dev_get_by_index_rcu(sock_net(skb->sk),
 317                                           skb->sk->sk_bound_dev_if);
 318                *err = var_dev(dev, dst);
 319                rcu_read_unlock();
 320        }
 321}
 322
 323META_COLLECTOR(int_sk_refcnt)
 324{
 325        SKIP_NONLOCAL(skb);
 326        dst->value = atomic_read(&skb->sk->sk_refcnt);
 327}
 328
 329META_COLLECTOR(int_sk_rcvbuf)
 330{
 331        SKIP_NONLOCAL(skb);
 332        dst->value = skb->sk->sk_rcvbuf;
 333}
 334
 335META_COLLECTOR(int_sk_shutdown)
 336{
 337        SKIP_NONLOCAL(skb);
 338        dst->value = skb->sk->sk_shutdown;
 339}
 340
 341META_COLLECTOR(int_sk_proto)
 342{
 343        SKIP_NONLOCAL(skb);
 344        dst->value = skb->sk->sk_protocol;
 345}
 346
 347META_COLLECTOR(int_sk_type)
 348{
 349        SKIP_NONLOCAL(skb);
 350        dst->value = skb->sk->sk_type;
 351}
 352
 353META_COLLECTOR(int_sk_rmem_alloc)
 354{
 355        SKIP_NONLOCAL(skb);
 356        dst->value = sk_rmem_alloc_get(skb->sk);
 357}
 358
 359META_COLLECTOR(int_sk_wmem_alloc)
 360{
 361        SKIP_NONLOCAL(skb);
 362        dst->value = sk_wmem_alloc_get(skb->sk);
 363}
 364
 365META_COLLECTOR(int_sk_omem_alloc)
 366{
 367        SKIP_NONLOCAL(skb);
 368        dst->value = atomic_read(&skb->sk->sk_omem_alloc);
 369}
 370
 371META_COLLECTOR(int_sk_rcv_qlen)
 372{
 373        SKIP_NONLOCAL(skb);
 374        dst->value = skb->sk->sk_receive_queue.qlen;
 375}
 376
 377META_COLLECTOR(int_sk_snd_qlen)
 378{
 379        SKIP_NONLOCAL(skb);
 380        dst->value = skb->sk->sk_write_queue.qlen;
 381}
 382
 383META_COLLECTOR(int_sk_wmem_queued)
 384{
 385        SKIP_NONLOCAL(skb);
 386        dst->value = skb->sk->sk_wmem_queued;
 387}
 388
 389META_COLLECTOR(int_sk_fwd_alloc)
 390{
 391        SKIP_NONLOCAL(skb);
 392        dst->value = skb->sk->sk_forward_alloc;
 393}
 394
 395META_COLLECTOR(int_sk_sndbuf)
 396{
 397        SKIP_NONLOCAL(skb);
 398        dst->value = skb->sk->sk_sndbuf;
 399}
 400
 401META_COLLECTOR(int_sk_alloc)
 402{
 403        SKIP_NONLOCAL(skb);
 404        dst->value = (__force int) skb->sk->sk_allocation;
 405}
 406
 407META_COLLECTOR(int_sk_hash)
 408{
 409        SKIP_NONLOCAL(skb);
 410        dst->value = skb->sk->sk_hash;
 411}
 412
 413META_COLLECTOR(int_sk_lingertime)
 414{
 415        SKIP_NONLOCAL(skb);
 416        dst->value = skb->sk->sk_lingertime / HZ;
 417}
 418
 419META_COLLECTOR(int_sk_err_qlen)
 420{
 421        SKIP_NONLOCAL(skb);
 422        dst->value = skb->sk->sk_error_queue.qlen;
 423}
 424
 425META_COLLECTOR(int_sk_ack_bl)
 426{
 427        SKIP_NONLOCAL(skb);
 428        dst->value = skb->sk->sk_ack_backlog;
 429}
 430
 431META_COLLECTOR(int_sk_max_ack_bl)
 432{
 433        SKIP_NONLOCAL(skb);
 434        dst->value = skb->sk->sk_max_ack_backlog;
 435}
 436
 437META_COLLECTOR(int_sk_prio)
 438{
 439        SKIP_NONLOCAL(skb);
 440        dst->value = skb->sk->sk_priority;
 441}
 442
 443META_COLLECTOR(int_sk_rcvlowat)
 444{
 445        SKIP_NONLOCAL(skb);
 446        dst->value = skb->sk->sk_rcvlowat;
 447}
 448
 449META_COLLECTOR(int_sk_rcvtimeo)
 450{
 451        SKIP_NONLOCAL(skb);
 452        dst->value = skb->sk->sk_rcvtimeo / HZ;
 453}
 454
 455META_COLLECTOR(int_sk_sndtimeo)
 456{
 457        SKIP_NONLOCAL(skb);
 458        dst->value = skb->sk->sk_sndtimeo / HZ;
 459}
 460
 461META_COLLECTOR(int_sk_sendmsg_off)
 462{
 463        SKIP_NONLOCAL(skb);
 464        dst->value = skb->sk->sk_sndmsg_off;
 465}
 466
 467META_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
 477struct meta_ops {
 478        void            (*get)(struct sk_buff *, struct tcf_pkt_info *,
 479                               struct meta_value *, struct meta_obj *, int *);
 480};
 481
 482#define META_ID(name) TCF_META_ID_##name
 483#define META_FUNC(name) { .get = meta_##name }
 484
 485/* Meta value operations table listing all meta value collectors and
 486 * assigns them to a type and meta id. */
 487static struct meta_ops __meta_ops[TCF_META_TYPE_MAX + 1][TCF_META_ID_MAX + 1] = {
 488        [TCF_META_TYPE_VAR] = {
 489                [META_ID(DEV)]                  = META_FUNC(var_dev),
 490                [META_ID(SK_BOUND_IF)]          = META_FUNC(var_sk_bound_if),
 491        },
 492        [TCF_META_TYPE_INT] = {
 493                [META_ID(RANDOM)]               = META_FUNC(int_random),
 494                [META_ID(LOADAVG_0)]            = META_FUNC(int_loadavg_0),
 495                [META_ID(LOADAVG_1)]            = META_FUNC(int_loadavg_1),
 496                [META_ID(LOADAVG_2)]            = META_FUNC(int_loadavg_2),
 497                [META_ID(DEV)]                  = META_FUNC(int_dev),
 498                [META_ID(PRIORITY)]             = META_FUNC(int_priority),
 499                [META_ID(PROTOCOL)]             = META_FUNC(int_protocol),
 500                [META_ID(PKTTYPE)]              = META_FUNC(int_pkttype),
 501                [META_ID(PKTLEN)]               = META_FUNC(int_pktlen),
 502                [META_ID(DATALEN)]              = META_FUNC(int_datalen),
 503                [META_ID(MACLEN)]               = META_FUNC(int_maclen),
 504                [META_ID(NFMARK)]               = META_FUNC(int_mark),
 505                [META_ID(TCINDEX)]              = META_FUNC(int_tcindex),
 506                [META_ID(RTCLASSID)]            = META_FUNC(int_rtclassid),
 507                [META_ID(RTIIF)]                = META_FUNC(int_rtiif),
 508                [META_ID(SK_FAMILY)]            = META_FUNC(int_sk_family),
 509                [META_ID(SK_STATE)]             = META_FUNC(int_sk_state),
 510                [META_ID(SK_REUSE)]             = META_FUNC(int_sk_reuse),
 511                [META_ID(SK_BOUND_IF)]          = META_FUNC(int_sk_bound_if),
 512                [META_ID(SK_REFCNT)]            = META_FUNC(int_sk_refcnt),
 513                [META_ID(SK_RCVBUF)]            = META_FUNC(int_sk_rcvbuf),
 514                [META_ID(SK_SNDBUF)]            = META_FUNC(int_sk_sndbuf),
 515                [META_ID(SK_SHUTDOWN)]          = META_FUNC(int_sk_shutdown),
 516                [META_ID(SK_PROTO)]             = META_FUNC(int_sk_proto),
 517                [META_ID(SK_TYPE)]              = META_FUNC(int_sk_type),
 518                [META_ID(SK_RMEM_ALLOC)]        = META_FUNC(int_sk_rmem_alloc),
 519                [META_ID(SK_WMEM_ALLOC)]        = META_FUNC(int_sk_wmem_alloc),
 520                [META_ID(SK_OMEM_ALLOC)]        = META_FUNC(int_sk_omem_alloc),
 521                [META_ID(SK_WMEM_QUEUED)]       = META_FUNC(int_sk_wmem_queued),
 522                [META_ID(SK_RCV_QLEN)]          = META_FUNC(int_sk_rcv_qlen),
 523                [META_ID(SK_SND_QLEN)]          = META_FUNC(int_sk_snd_qlen),
 524                [META_ID(SK_ERR_QLEN)]          = META_FUNC(int_sk_err_qlen),
 525                [META_ID(SK_FORWARD_ALLOCS)]    = META_FUNC(int_sk_fwd_alloc),
 526                [META_ID(SK_ALLOCS)]            = META_FUNC(int_sk_alloc),
 527                [META_ID(SK_HASH)]              = META_FUNC(int_sk_hash),
 528                [META_ID(SK_LINGERTIME)]        = META_FUNC(int_sk_lingertime),
 529                [META_ID(SK_ACK_BACKLOG)]       = META_FUNC(int_sk_ack_bl),
 530                [META_ID(SK_MAX_ACK_BACKLOG)]   = META_FUNC(int_sk_max_ack_bl),
 531                [META_ID(SK_PRIO)]              = META_FUNC(int_sk_prio),
 532                [META_ID(SK_RCVLOWAT)]          = META_FUNC(int_sk_rcvlowat),
 533                [META_ID(SK_RCVTIMEO)]          = META_FUNC(int_sk_rcvtimeo),
 534                [META_ID(SK_SNDTIMEO)]          = META_FUNC(int_sk_sndtimeo),
 535                [META_ID(SK_SENDMSG_OFF)]       = META_FUNC(int_sk_sendmsg_off),
 536                [META_ID(SK_WRITE_PENDING)]     = META_FUNC(int_sk_write_pend),
 537                [META_ID(VLAN_TAG)]             = META_FUNC(int_vlan_tag),
 538                [META_ID(RXHASH)]               = META_FUNC(int_rxhash),
 539        }
 540};
 541
 542static inline struct meta_ops *meta_ops(struct meta_value *val)
 543{
 544        return &__meta_ops[meta_type(val)][meta_id(val)];
 545}
 546
 547/**************************************************************************
 548 * Type specific operations for TCF_META_TYPE_VAR
 549 **************************************************************************/
 550
 551static int meta_var_compare(struct meta_obj *a, struct meta_obj *b)
 552{
 553        int r = a->len - b->len;
 554
 555        if (r == 0)
 556                r = memcmp((void *) a->value, (void *) b->value, a->len);
 557
 558        return r;
 559}
 560
 561static int meta_var_change(struct meta_value *dst, struct nlattr *nla)
 562{
 563        int len = nla_len(nla);
 564
 565        dst->val = (unsigned long)kmemdup(nla_data(nla), len, GFP_KERNEL);
 566        if (dst->val == 0UL)
 567                return -ENOMEM;
 568        dst->len = len;
 569        return 0;
 570}
 571
 572static void meta_var_destroy(struct meta_value *v)
 573{
 574        kfree((void *) v->val);
 575}
 576
 577static void meta_var_apply_extras(struct meta_value *v,
 578                                  struct meta_obj *dst)
 579{
 580        int shift = v->hdr.shift;
 581
 582        if (shift && shift < dst->len)
 583                dst->len -= shift;
 584}
 585
 586static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 587{
 588        if (v->val && v->len &&
 589            nla_put(skb, tlv, v->len, (void *) v->val))
 590                goto nla_put_failure;
 591        return 0;
 592
 593nla_put_failure:
 594        return -1;
 595}
 596
 597/**************************************************************************
 598 * Type specific operations for TCF_META_TYPE_INT
 599 **************************************************************************/
 600
 601static 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
 614static 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
 628static 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
 638static int meta_int_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 639{
 640        if (v->len == sizeof(unsigned long)) {
 641                if (nla_put(skb, tlv, sizeof(unsigned long), &v->val))
 642                        goto nla_put_failure;
 643        } else if (v->len == sizeof(u32)) {
 644                if (nla_put_u32(skb, tlv, v->val))
 645                        goto nla_put_failure;
 646        }
 647
 648        return 0;
 649
 650nla_put_failure:
 651        return -1;
 652}
 653
 654/**************************************************************************
 655 * Type specific operations table
 656 **************************************************************************/
 657
 658struct meta_type_ops {
 659        void    (*destroy)(struct meta_value *);
 660        int     (*compare)(struct meta_obj *, struct meta_obj *);
 661        int     (*change)(struct meta_value *, struct nlattr *);
 662        void    (*apply_extras)(struct meta_value *, struct meta_obj *);
 663        int     (*dump)(struct sk_buff *, struct meta_value *, int);
 664};
 665
 666static struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX + 1] = {
 667        [TCF_META_TYPE_VAR] = {
 668                .destroy = meta_var_destroy,
 669                .compare = meta_var_compare,
 670                .change = meta_var_change,
 671                .apply_extras = meta_var_apply_extras,
 672                .dump = meta_var_dump
 673        },
 674        [TCF_META_TYPE_INT] = {
 675                .compare = meta_int_compare,
 676                .change = meta_int_change,
 677                .apply_extras = meta_int_apply_extras,
 678                .dump = meta_int_dump
 679        }
 680};
 681
 682static inline struct meta_type_ops *meta_type_ops(struct meta_value *v)
 683{
 684        return &__meta_type_ops[meta_type(v)];
 685}
 686
 687/**************************************************************************
 688 * Core
 689 **************************************************************************/
 690
 691static int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info,
 692                    struct meta_value *v, struct meta_obj *dst)
 693{
 694        int err = 0;
 695
 696        if (meta_id(v) == TCF_META_ID_VALUE) {
 697                dst->value = v->val;
 698                dst->len = v->len;
 699                return 0;
 700        }
 701
 702        meta_ops(v)->get(skb, info, v, dst, &err);
 703        if (err < 0)
 704                return err;
 705
 706        if (meta_type_ops(v)->apply_extras)
 707                meta_type_ops(v)->apply_extras(v, dst);
 708
 709        return 0;
 710}
 711
 712static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
 713                         struct tcf_pkt_info *info)
 714{
 715        int r;
 716        struct meta_match *meta = (struct meta_match *) m->data;
 717        struct meta_obj l_value, r_value;
 718
 719        if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 ||
 720            meta_get(skb, info, &meta->rvalue, &r_value) < 0)
 721                return 0;
 722
 723        r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value);
 724
 725        switch (meta->lvalue.hdr.op) {
 726        case TCF_EM_OPND_EQ:
 727                return !r;
 728        case TCF_EM_OPND_LT:
 729                return r < 0;
 730        case TCF_EM_OPND_GT:
 731                return r > 0;
 732        }
 733
 734        return 0;
 735}
 736
 737static void meta_delete(struct meta_match *meta)
 738{
 739        if (meta) {
 740                struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
 741
 742                if (ops && ops->destroy) {
 743                        ops->destroy(&meta->lvalue);
 744                        ops->destroy(&meta->rvalue);
 745                }
 746        }
 747
 748        kfree(meta);
 749}
 750
 751static inline int meta_change_data(struct meta_value *dst, struct nlattr *nla)
 752{
 753        if (nla) {
 754                if (nla_len(nla) == 0)
 755                        return -EINVAL;
 756
 757                return meta_type_ops(dst)->change(dst, nla);
 758        }
 759
 760        return 0;
 761}
 762
 763static inline int meta_is_supported(struct meta_value *val)
 764{
 765        return !meta_id(val) || meta_ops(val)->get;
 766}
 767
 768static const struct nla_policy meta_policy[TCA_EM_META_MAX + 1] = {
 769        [TCA_EM_META_HDR]       = { .len = sizeof(struct tcf_meta_hdr) },
 770};
 771
 772static int em_meta_change(struct tcf_proto *tp, void *data, int len,
 773                          struct tcf_ematch *m)
 774{
 775        int err;
 776        struct nlattr *tb[TCA_EM_META_MAX + 1];
 777        struct tcf_meta_hdr *hdr;
 778        struct meta_match *meta = NULL;
 779
 780        err = nla_parse(tb, TCA_EM_META_MAX, data, len, meta_policy);
 781        if (err < 0)
 782                goto errout;
 783
 784        err = -EINVAL;
 785        if (tb[TCA_EM_META_HDR] == NULL)
 786                goto errout;
 787        hdr = nla_data(tb[TCA_EM_META_HDR]);
 788
 789        if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) ||
 790            TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX ||
 791            TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX ||
 792            TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX)
 793                goto errout;
 794
 795        meta = kzalloc(sizeof(*meta), GFP_KERNEL);
 796        if (meta == NULL)
 797                goto errout;
 798
 799        memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));
 800        memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right));
 801
 802        if (!meta_is_supported(&meta->lvalue) ||
 803            !meta_is_supported(&meta->rvalue)) {
 804                err = -EOPNOTSUPP;
 805                goto errout;
 806        }
 807
 808        if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE]) < 0 ||
 809            meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE]) < 0)
 810                goto errout;
 811
 812        m->datalen = sizeof(*meta);
 813        m->data = (unsigned long) meta;
 814
 815        err = 0;
 816errout:
 817        if (err && meta)
 818                meta_delete(meta);
 819        return err;
 820}
 821
 822static void em_meta_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
 823{
 824        if (m)
 825                meta_delete((struct meta_match *) m->data);
 826}
 827
 828static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em)
 829{
 830        struct meta_match *meta = (struct meta_match *) em->data;
 831        struct tcf_meta_hdr hdr;
 832        struct meta_type_ops *ops;
 833
 834        memset(&hdr, 0, sizeof(hdr));
 835        memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left));
 836        memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right));
 837
 838        if (nla_put(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr))
 839                goto nla_put_failure;
 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
 848nla_put_failure:
 849        return -1;
 850}
 851
 852static 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
 862static int __init init_em_meta(void)
 863{
 864        return tcf_em_register(&em_meta_ops);
 865}
 866
 867static void __exit exit_em_meta(void)
 868{
 869        tcf_em_unregister(&em_meta_ops);
 870}
 871
 872MODULE_LICENSE("GPL");
 873
 874module_init(init_em_meta);
 875module_exit(exit_em_meta);
 876
 877MODULE_ALIAS_TCF_EMATCH(TCF_EM_META);
 878
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