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/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{
  78        unsigned long           value;
  79        unsigned int            len;
  80};
  81
  82struct meta_value
  83{
  84        struct tcf_meta_val     hdr;
  85        unsigned long           val;
  86        unsigned int            len;
  87};
  88
  89struct meta_match
  90{
  91        struct meta_value       lvalue;
  92        struct meta_value       rvalue;
  93};
  94
  95static inline int meta_id(struct meta_value *v)
  96{
  97        return TCF_META_ID(v->hdr.kind);
  98}
  99
 100static inline int meta_type(struct meta_value *v)
 101{
 102        return TCF_META_TYPE(v->hdr.kind);
 103}
 104
 105#define META_COLLECTOR(FUNC) static void meta_##FUNC(struct sk_buff *skb, \
 106        struct tcf_pkt_info *info, struct meta_value *v, \
 107        struct meta_obj *dst, int *err)
 108
 109/**************************************************************************
 110 * System status & misc
 111 **************************************************************************/
 112
 113META_COLLECTOR(int_random)
 114{
 115        get_random_bytes(&dst->value, sizeof(dst->value));
 116}
 117
 118static inline unsigned long fixed_loadavg(int load)
 119{
 120        int rnd_load = load + (FIXED_1/200);
 121        int rnd_frac = ((rnd_load & (FIXED_1-1)) * 100) >> FSHIFT;
 122
 123        return ((rnd_load >> FSHIFT) * 100) + rnd_frac;
 124}
 125
 126META_COLLECTOR(int_loadavg_0)
 127{
 128        dst->value = fixed_loadavg(avenrun[0]);
 129}
 130
 131META_COLLECTOR(int_loadavg_1)
 132{
 133        dst->value = fixed_loadavg(avenrun[1]);
 134}
 135
 136META_COLLECTOR(int_loadavg_2)
 137{
 138        dst->value = fixed_loadavg(avenrun[2]);
 139}
 140
 141/**************************************************************************
 142 * Device names & indices
 143 **************************************************************************/
 144
 145static inline int int_dev(struct net_device *dev, struct meta_obj *dst)
 146{
 147        if (unlikely(dev == NULL))
 148                return -1;
 149
 150        dst->value = dev->ifindex;
 151        return 0;
 152}
 153
 154static inline int var_dev(struct net_device *dev, struct meta_obj *dst)
 155{
 156        if (unlikely(dev == NULL))
 157                return -1;
 158
 159        dst->value = (unsigned long) dev->name;
 160        dst->len = strlen(dev->name);
 161        return 0;
 162}
 163
 164META_COLLECTOR(int_dev)
 165{
 166        *err = int_dev(skb->dev, dst);
 167}
 168
 169META_COLLECTOR(var_dev)
 170{
 171        *err = var_dev(skb->dev, dst);
 172}
 173
 174/**************************************************************************
 175 * vlan tag
 176 **************************************************************************/
 177
 178META_COLLECTOR(int_vlan_tag)
 179{
 180        unsigned short tag;
 181
 182        tag = vlan_tx_tag_get(skb);
 183        if (!tag && __vlan_get_tag(skb, &tag))
 184                *err = -1;
 185        else
 186                dst->value = tag;
 187}
 188
 189
 190
 191/**************************************************************************
 192 * skb attributes
 193 **************************************************************************/
 194
 195META_COLLECTOR(int_priority)
 196{
 197        dst->value = skb->priority;
 198}
 199
 200META_COLLECTOR(int_protocol)
 201{
 202        /* Let userspace take care of the byte ordering */
 203        dst->value = skb->protocol;
 204}
 205
 206META_COLLECTOR(int_pkttype)
 207{
 208        dst->value = skb->pkt_type;
 209}
 210
 211META_COLLECTOR(int_pktlen)
 212{
 213        dst->value = skb->len;
 214}
 215
 216META_COLLECTOR(int_datalen)
 217{
 218        dst->value = skb->data_len;
 219}
 220
 221META_COLLECTOR(int_maclen)
 222{
 223        dst->value = skb->mac_len;
 224}
 225
 226/**************************************************************************
 227 * Netfilter
 228 **************************************************************************/
 229
 230META_COLLECTOR(int_mark)
 231{
 232        dst->value = skb->mark;
 233}
 234
 235/**************************************************************************
 236 * Traffic Control
 237 **************************************************************************/
 238
 239META_COLLECTOR(int_tcindex)
 240{
 241        dst->value = skb->tc_index;
 242}
 243
 244/**************************************************************************
 245 * Routing
 246 **************************************************************************/
 247
 248META_COLLECTOR(int_rtclassid)
 249{
 250        if (unlikely(skb_dst(skb) == NULL))
 251                *err = -1;
 252        else
 253#ifdef CONFIG_NET_CLS_ROUTE
 254                dst->value = skb_dst(skb)->tclassid;
 255#else
 256                dst->value = 0;
 257#endif
 258}
 259
 260META_COLLECTOR(int_rtiif)
 261{
 262        if (unlikely(skb_rtable(skb) == NULL))
 263                *err = -1;
 264        else
 265                dst->value = skb_rtable(skb)->fl.iif;
 266}
 267
 268/**************************************************************************
 269 * Socket Attributes
 270 **************************************************************************/
 271
 272#define SKIP_NONLOCAL(skb)                      \
 273        if (unlikely(skb->sk == NULL)) {        \
 274                *err = -1;                      \
 275                return;                         \
 276        }
 277
 278META_COLLECTOR(int_sk_family)
 279{
 280        SKIP_NONLOCAL(skb);
 281        dst->value = skb->sk->sk_family;
 282}
 283
 284META_COLLECTOR(int_sk_state)
 285{
 286        SKIP_NONLOCAL(skb);
 287        dst->value = skb->sk->sk_state;
 288}
 289
 290META_COLLECTOR(int_sk_reuse)
 291{
 292        SKIP_NONLOCAL(skb);
 293        dst->value = skb->sk->sk_reuse;
 294}
 295
 296META_COLLECTOR(int_sk_bound_if)
 297{
 298        SKIP_NONLOCAL(skb);
 299        /* No error if bound_dev_if is 0, legal userspace check */
 300        dst->value = skb->sk->sk_bound_dev_if;
 301}
 302
 303META_COLLECTOR(var_sk_bound_if)
 304{
 305        SKIP_NONLOCAL(skb);
 306
 307        if (skb->sk->sk_bound_dev_if == 0) {
 308                dst->value = (unsigned long) "any";
 309                dst->len = 3;
 310        } else {
 311                struct net_device *dev;
 312
 313                rcu_read_lock();
 314                dev = dev_get_by_index_rcu(sock_net(skb->sk),
 315                                           skb->sk->sk_bound_dev_if);
 316                *err = var_dev(dev, dst);
 317                rcu_read_unlock();
 318        }
 319}
 320
 321META_COLLECTOR(int_sk_refcnt)
 322{
 323        SKIP_NONLOCAL(skb);
 324        dst->value = atomic_read(&skb->sk->sk_refcnt);
 325}
 326
 327META_COLLECTOR(int_sk_rcvbuf)
 328{
 329        SKIP_NONLOCAL(skb);
 330        dst->value = skb->sk->sk_rcvbuf;
 331}
 332
 333META_COLLECTOR(int_sk_shutdown)
 334{
 335        SKIP_NONLOCAL(skb);
 336        dst->value = skb->sk->sk_shutdown;
 337}
 338
 339META_COLLECTOR(int_sk_proto)
 340{
 341        SKIP_NONLOCAL(skb);
 342        dst->value = skb->sk->sk_protocol;
 343}
 344
 345META_COLLECTOR(int_sk_type)
 346{
 347        SKIP_NONLOCAL(skb);
 348        dst->value = skb->sk->sk_type;
 349}
 350
 351META_COLLECTOR(int_sk_rmem_alloc)
 352{
 353        SKIP_NONLOCAL(skb);
 354        dst->value = sk_rmem_alloc_get(skb->sk);
 355}
 356
 357META_COLLECTOR(int_sk_wmem_alloc)
 358{
 359        SKIP_NONLOCAL(skb);
 360        dst->value = sk_wmem_alloc_get(skb->sk);
 361}
 362
 363META_COLLECTOR(int_sk_omem_alloc)
 364{
 365        SKIP_NONLOCAL(skb);
 366        dst->value = atomic_read(&skb->sk->sk_omem_alloc);
 367}
 368
 369META_COLLECTOR(int_sk_rcv_qlen)
 370{
 371        SKIP_NONLOCAL(skb);
 372        dst->value = skb->sk->sk_receive_queue.qlen;
 373}
 374
 375META_COLLECTOR(int_sk_snd_qlen)
 376{
 377        SKIP_NONLOCAL(skb);
 378        dst->value = skb->sk->sk_write_queue.qlen;
 379}
 380
 381META_COLLECTOR(int_sk_wmem_queued)
 382{
 383        SKIP_NONLOCAL(skb);
 384        dst->value = skb->sk->sk_wmem_queued;
 385}
 386
 387META_COLLECTOR(int_sk_fwd_alloc)
 388{
 389        SKIP_NONLOCAL(skb);
 390        dst->value = skb->sk->sk_forward_alloc;
 391}
 392
 393META_COLLECTOR(int_sk_sndbuf)
 394{
 395        SKIP_NONLOCAL(skb);
 396        dst->value = skb->sk->sk_sndbuf;
 397}
 398
 399META_COLLECTOR(int_sk_alloc)
 400{
 401        SKIP_NONLOCAL(skb);
 402        dst->value = skb->sk->sk_allocation;
 403}
 404
 405META_COLLECTOR(int_sk_route_caps)
 406{
 407        SKIP_NONLOCAL(skb);
 408        dst->value = skb->sk->sk_route_caps;
 409}
 410
 411META_COLLECTOR(int_sk_hash)
 412{
 413        SKIP_NONLOCAL(skb);
 414        dst->value = skb->sk->sk_hash;
 415}
 416
 417META_COLLECTOR(int_sk_lingertime)
 418{
 419        SKIP_NONLOCAL(skb);
 420        dst->value = skb->sk->sk_lingertime / HZ;
 421}
 422
 423META_COLLECTOR(int_sk_err_qlen)
 424{
 425        SKIP_NONLOCAL(skb);
 426        dst->value = skb->sk->sk_error_queue.qlen;
 427}
 428
 429META_COLLECTOR(int_sk_ack_bl)
 430{
 431        SKIP_NONLOCAL(skb);
 432        dst->value = skb->sk->sk_ack_backlog;
 433}
 434
 435META_COLLECTOR(int_sk_max_ack_bl)
 436{
 437        SKIP_NONLOCAL(skb);
 438        dst->value = skb->sk->sk_max_ack_backlog;
 439}
 440
 441META_COLLECTOR(int_sk_prio)
 442{
 443        SKIP_NONLOCAL(skb);
 444        dst->value = skb->sk->sk_priority;
 445}
 446
 447META_COLLECTOR(int_sk_rcvlowat)
 448{
 449        SKIP_NONLOCAL(skb);
 450        dst->value = skb->sk->sk_rcvlowat;
 451}
 452
 453META_COLLECTOR(int_sk_rcvtimeo)
 454{
 455        SKIP_NONLOCAL(skb);
 456        dst->value = skb->sk->sk_rcvtimeo / HZ;
 457}
 458
 459META_COLLECTOR(int_sk_sndtimeo)
 460{
 461        SKIP_NONLOCAL(skb);
 462        dst->value = skb->sk->sk_sndtimeo / HZ;
 463}
 464
 465META_COLLECTOR(int_sk_sendmsg_off)
 466{
 467        SKIP_NONLOCAL(skb);
 468        dst->value = skb->sk->sk_sndmsg_off;
 469}
 470
 471META_COLLECTOR(int_sk_write_pend)
 472{
 473        SKIP_NONLOCAL(skb);
 474        dst->value = skb->sk->sk_write_pending;
 475}
 476
 477/**************************************************************************
 478 * Meta value collectors assignment table
 479 **************************************************************************/
 480
 481struct meta_ops
 482{
 483        void            (*get)(struct sk_buff *, struct tcf_pkt_info *,
 484                               struct meta_value *, struct meta_obj *, int *);
 485};
 486
 487#define META_ID(name) TCF_META_ID_##name
 488#define META_FUNC(name) { .get = meta_##name }
 489
 490/* Meta value operations table listing all meta value collectors and
 491 * assigns them to a type and meta id. */
 492static struct meta_ops __meta_ops[TCF_META_TYPE_MAX+1][TCF_META_ID_MAX+1] = {
 493        [TCF_META_TYPE_VAR] = {
 494                [META_ID(DEV)]                  = META_FUNC(var_dev),
 495                [META_ID(SK_BOUND_IF)]          = META_FUNC(var_sk_bound_if),
 496        },
 497        [TCF_META_TYPE_INT] = {
 498                [META_ID(RANDOM)]               = META_FUNC(int_random),
 499                [META_ID(LOADAVG_0)]            = META_FUNC(int_loadavg_0),
 500                [META_ID(LOADAVG_1)]            = META_FUNC(int_loadavg_1),
 501                [META_ID(LOADAVG_2)]            = META_FUNC(int_loadavg_2),
 502                [META_ID(DEV)]                  = META_FUNC(int_dev),
 503                [META_ID(PRIORITY)]             = META_FUNC(int_priority),
 504                [META_ID(PROTOCOL)]             = META_FUNC(int_protocol),
 505                [META_ID(PKTTYPE)]              = META_FUNC(int_pkttype),
 506                [META_ID(PKTLEN)]               = META_FUNC(int_pktlen),
 507                [META_ID(DATALEN)]              = META_FUNC(int_datalen),
 508                [META_ID(MACLEN)]               = META_FUNC(int_maclen),
 509                [META_ID(NFMARK)]               = META_FUNC(int_mark),
 510                [META_ID(TCINDEX)]              = META_FUNC(int_tcindex),
 511                [META_ID(RTCLASSID)]            = META_FUNC(int_rtclassid),
 512                [META_ID(RTIIF)]                = META_FUNC(int_rtiif),
 513                [META_ID(SK_FAMILY)]            = META_FUNC(int_sk_family),
 514                [META_ID(SK_STATE)]             = META_FUNC(int_sk_state),
 515                [META_ID(SK_REUSE)]             = META_FUNC(int_sk_reuse),
 516                [META_ID(SK_BOUND_IF)]          = META_FUNC(int_sk_bound_if),
 517                [META_ID(SK_REFCNT)]            = META_FUNC(int_sk_refcnt),
 518                [META_ID(SK_RCVBUF)]            = META_FUNC(int_sk_rcvbuf),
 519                [META_ID(SK_SNDBUF)]            = META_FUNC(int_sk_sndbuf),
 520                [META_ID(SK_SHUTDOWN)]          = META_FUNC(int_sk_shutdown),
 521                [META_ID(SK_PROTO)]             = META_FUNC(int_sk_proto),
 522                [META_ID(SK_TYPE)]              = META_FUNC(int_sk_type),
 523                [META_ID(SK_RMEM_ALLOC)]        = META_FUNC(int_sk_rmem_alloc),
 524                [META_ID(SK_WMEM_ALLOC)]        = META_FUNC(int_sk_wmem_alloc),
 525                [META_ID(SK_OMEM_ALLOC)]        = META_FUNC(int_sk_omem_alloc),
 526                [META_ID(SK_WMEM_QUEUED)]       = META_FUNC(int_sk_wmem_queued),
 527                [META_ID(SK_RCV_QLEN)]          = META_FUNC(int_sk_rcv_qlen),
 528                [META_ID(SK_SND_QLEN)]          = META_FUNC(int_sk_snd_qlen),
 529                [META_ID(SK_ERR_QLEN)]          = META_FUNC(int_sk_err_qlen),
 530                [META_ID(SK_FORWARD_ALLOCS)]    = META_FUNC(int_sk_fwd_alloc),
 531                [META_ID(SK_ALLOCS)]            = META_FUNC(int_sk_alloc),
 532                [META_ID(SK_ROUTE_CAPS)]        = META_FUNC(int_sk_route_caps),
 533                [META_ID(SK_HASH)]              = META_FUNC(int_sk_hash),
 534                [META_ID(SK_LINGERTIME)]        = META_FUNC(int_sk_lingertime),
 535                [META_ID(SK_ACK_BACKLOG)]       = META_FUNC(int_sk_ack_bl),
 536                [META_ID(SK_MAX_ACK_BACKLOG)]   = META_FUNC(int_sk_max_ack_bl),
 537                [META_ID(SK_PRIO)]              = META_FUNC(int_sk_prio),
 538                [META_ID(SK_RCVLOWAT)]          = META_FUNC(int_sk_rcvlowat),
 539                [META_ID(SK_RCVTIMEO)]          = META_FUNC(int_sk_rcvtimeo),
 540                [META_ID(SK_SNDTIMEO)]          = META_FUNC(int_sk_sndtimeo),
 541                [META_ID(SK_SENDMSG_OFF)]       = META_FUNC(int_sk_sendmsg_off),
 542                [META_ID(SK_WRITE_PENDING)]     = META_FUNC(int_sk_write_pend),
 543                [META_ID(VLAN_TAG)]             = META_FUNC(int_vlan_tag),
 544        }
 545};
 546
 547static inline struct meta_ops * meta_ops(struct meta_value *val)
 548{
 549        return &__meta_ops[meta_type(val)][meta_id(val)];
 550}
 551
 552/**************************************************************************
 553 * Type specific operations for TCF_META_TYPE_VAR
 554 **************************************************************************/
 555
 556static int meta_var_compare(struct meta_obj *a, struct meta_obj *b)
 557{
 558        int r = a->len - b->len;
 559
 560        if (r == 0)
 561                r = memcmp((void *) a->value, (void *) b->value, a->len);
 562
 563        return r;
 564}
 565
 566static int meta_var_change(struct meta_value *dst, struct nlattr *nla)
 567{
 568        int len = nla_len(nla);
 569
 570        dst->val = (unsigned long)kmemdup(nla_data(nla), len, GFP_KERNEL);
 571        if (dst->val == 0UL)
 572                return -ENOMEM;
 573        dst->len = len;
 574        return 0;
 575}
 576
 577static void meta_var_destroy(struct meta_value *v)
 578{
 579        kfree((void *) v->val);
 580}
 581
 582static void meta_var_apply_extras(struct meta_value *v,
 583                                  struct meta_obj *dst)
 584{
 585        int shift = v->hdr.shift;
 586
 587        if (shift && shift < dst->len)
 588                dst->len -= shift;
 589}
 590
 591static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 592{
 593        if (v->val && v->len)
 594                NLA_PUT(skb, tlv, v->len, (void *) v->val);
 595        return 0;
 596
 597nla_put_failure:
 598        return -1;
 599}
 600
 601/**************************************************************************
 602 * Type specific operations for TCF_META_TYPE_INT
 603 **************************************************************************/
 604
 605static int meta_int_compare(struct meta_obj *a, struct meta_obj *b)
 606{
 607        /* Let gcc optimize it, the unlikely is not really based on
 608         * some numbers but jump free code for mismatches seems
 609         * more logical. */
 610        if (unlikely(a->value == b->value))
 611                return 0;
 612        else if (a->value < b->value)
 613                return -1;
 614        else
 615                return 1;
 616}
 617
 618static int meta_int_change(struct meta_value *dst, struct nlattr *nla)
 619{
 620        if (nla_len(nla) >= sizeof(unsigned long)) {
 621                dst->val = *(unsigned long *) nla_data(nla);
 622                dst->len = sizeof(unsigned long);
 623        } else if (nla_len(nla) == sizeof(u32)) {
 624                dst->val = nla_get_u32(nla);
 625                dst->len = sizeof(u32);
 626        } else
 627                return -EINVAL;
 628
 629        return 0;
 630}
 631
 632static void meta_int_apply_extras(struct meta_value *v,
 633                                  struct meta_obj *dst)
 634{
 635        if (v->hdr.shift)
 636                dst->value >>= v->hdr.shift;
 637
 638        if (v->val)
 639                dst->value &= v->val;
 640}
 641
 642static int meta_int_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 643{
 644        if (v->len == sizeof(unsigned long))
 645                NLA_PUT(skb, tlv, sizeof(unsigned long), &v->val);
 646        else if (v->len == sizeof(u32)) {
 647                NLA_PUT_U32(skb, tlv, v->val);
 648        }
 649
 650        return 0;
 651
 652nla_put_failure:
 653        return -1;
 654}
 655
 656/**************************************************************************
 657 * Type specific operations table
 658 **************************************************************************/
 659
 660struct meta_type_ops
 661{
 662        void    (*destroy)(struct meta_value *);
 663        int     (*compare)(struct meta_obj *, struct meta_obj *);
 664        int     (*change)(struct meta_value *, struct nlattr *);
 665        void    (*apply_extras)(struct meta_value *, struct meta_obj *);
 666        int     (*dump)(struct sk_buff *, struct meta_value *, int);
 667};
 668
 669static struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX+1] = {
 670        [TCF_META_TYPE_VAR] = {
 671                .destroy = meta_var_destroy,
 672                .compare = meta_var_compare,
 673                .change = meta_var_change,
 674                .apply_extras = meta_var_apply_extras,
 675                .dump = meta_var_dump
 676        },
 677        [TCF_META_TYPE_INT] = {
 678                .compare = meta_int_compare,
 679                .change = meta_int_change,
 680                .apply_extras = meta_int_apply_extras,
 681                .dump = meta_int_dump
 682        }
 683};
 684
 685static inline struct meta_type_ops * meta_type_ops(struct meta_value *v)
 686{
 687        return &__meta_type_ops[meta_type(v)];
 688}
 689
 690/**************************************************************************
 691 * Core
 692 **************************************************************************/
 693
 694static int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info,
 695                    struct meta_value *v, struct meta_obj *dst)
 696{
 697        int err = 0;
 698
 699        if (meta_id(v) == TCF_META_ID_VALUE) {
 700                dst->value = v->val;
 701                dst->len = v->len;
 702                return 0;
 703        }
 704
 705        meta_ops(v)->get(skb, info, v, dst, &err);
 706        if (err < 0)
 707                return err;
 708
 709        if (meta_type_ops(v)->apply_extras)
 710            meta_type_ops(v)->apply_extras(v, dst);
 711
 712        return 0;
 713}
 714
 715static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
 716                         struct tcf_pkt_info *info)
 717{
 718        int r;
 719        struct meta_match *meta = (struct meta_match *) m->data;
 720        struct meta_obj l_value, r_value;
 721
 722        if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 ||
 723            meta_get(skb, info, &meta->rvalue, &r_value) < 0)
 724                return 0;
 725
 726        r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value);
 727
 728        switch (meta->lvalue.hdr.op) {
 729                case TCF_EM_OPND_EQ:
 730                        return !r;
 731                case TCF_EM_OPND_LT:
 732                        return r < 0;
 733                case TCF_EM_OPND_GT:
 734                        return r > 0;
 735        }
 736
 737        return 0;
 738}
 739
 740static void meta_delete(struct meta_match *meta)
 741{
 742        if (meta) {
 743                struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
 744
 745                if (ops && ops->destroy) {
 746                        ops->destroy(&meta->lvalue);
 747                        ops->destroy(&meta->rvalue);
 748                }
 749        }
 750
 751        kfree(meta);
 752}
 753
 754static inline int meta_change_data(struct meta_value *dst, struct nlattr *nla)
 755{
 756        if (nla) {
 757                if (nla_len(nla) == 0)
 758                        return -EINVAL;
 759
 760                return meta_type_ops(dst)->change(dst, nla);
 761        }
 762
 763        return 0;
 764}
 765
 766static inline int meta_is_supported(struct meta_value *val)
 767{
 768        return (!meta_id(val) || meta_ops(val)->get);
 769}
 770
 771static const struct nla_policy meta_policy[TCA_EM_META_MAX + 1] = {
 772        [TCA_EM_META_HDR]       = { .len = sizeof(struct tcf_meta_hdr) },
 773};
 774
 775static int em_meta_change(struct tcf_proto *tp, void *data, int len,
 776                          struct tcf_ematch *m)
 777{
 778        int err;
 779        struct nlattr *tb[TCA_EM_META_MAX + 1];
 780        struct tcf_meta_hdr *hdr;
 781        struct meta_match *meta = NULL;
 782
 783        err = nla_parse(tb, TCA_EM_META_MAX, data, len, meta_policy);
 784        if (err < 0)
 785                goto errout;
 786
 787        err = -EINVAL;
 788        if (tb[TCA_EM_META_HDR] == NULL)
 789                goto errout;
 790        hdr = nla_data(tb[TCA_EM_META_HDR]);
 791
 792        if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) ||
 793            TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX ||
 794            TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX ||
 795            TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX)
 796                goto errout;
 797
 798        meta = kzalloc(sizeof(*meta), GFP_KERNEL);
 799        if (meta == NULL)
 800                goto errout;
 801
 802        memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));
 803        memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right));
 804
 805        if (!meta_is_supported(&meta->lvalue) ||
 806            !meta_is_supported(&meta->rvalue)) {
 807                err = -EOPNOTSUPP;
 808                goto errout;
 809        }
 810
 811        if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE]) < 0 ||
 812            meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE]) < 0)
 813                goto errout;
 814
 815        m->datalen = sizeof(*meta);
 816        m->data = (unsigned long) meta;
 817
 818        err = 0;
 819errout:
 820        if (err && meta)
 821                meta_delete(meta);
 822        return err;
 823}
 824
 825static void em_meta_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
 826{
 827        if (m)
 828                meta_delete((struct meta_match *) m->data);
 829}
 830
 831static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em)
 832{
 833        struct meta_match *meta = (struct meta_match *) em->data;
 834        struct tcf_meta_hdr hdr;
 835        struct meta_type_ops *ops;
 836
 837        memset(&hdr, 0, sizeof(hdr));
 838        memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left));
 839        memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right));
 840
 841        NLA_PUT(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr);
 842
 843        ops = meta_type_ops(&meta->lvalue);
 844        if (ops->dump(skb, &meta->lvalue, TCA_EM_META_LVALUE) < 0 ||
 845            ops->dump(skb, &meta->rvalue, TCA_EM_META_RVALUE) < 0)
 846                goto nla_put_failure;
 847
 848        return 0;
 849
 850nla_put_failure:
 851        return -1;
 852}
 853
 854static struct tcf_ematch_ops em_meta_ops = {
 855        .kind     = TCF_EM_META,
 856        .change   = em_meta_change,
 857        .match    = em_meta_match,
 858        .destroy  = em_meta_destroy,
 859        .dump     = em_meta_dump,
 860        .owner    = THIS_MODULE,
 861        .link     = LIST_HEAD_INIT(em_meta_ops.link)
 862};
 863
 864static int __init init_em_meta(void)
 865{
 866        return tcf_em_register(&em_meta_ops);
 867}
 868
 869static void __exit exit_em_meta(void)
 870{
 871        tcf_em_unregister(&em_meta_ops);
 872}
 873
 874MODULE_LICENSE("GPL");
 875
 876module_init(init_em_meta);
 877module_exit(exit_em_meta);
 878
 879MODULE_ALIAS_TCF_EMATCH(TCF_EM_META);
 880