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/if_vlan.h>
  69#include <linux/tc_ematch/tc_em_meta.h>
  70#include <net/dst.h>
  71#include <net/route.h>
  72#include <net/pkt_cls.h>
  73#include <net/sock.h>
  74
  75struct meta_obj
  76{
  77        unsigned long           value;
  78        unsigned int            len;
  79};
  80
  81struct meta_value
  82{
  83        struct tcf_meta_val     hdr;
  84        unsigned long           val;
  85        unsigned int            len;
  86};
  87
  88struct meta_match
  89{
  90        struct meta_value       lvalue;
  91        struct meta_value       rvalue;
  92};
  93
  94static inline int meta_id(struct meta_value *v)
  95{
  96        return TCF_META_ID(v->hdr.kind);
  97}
  98
  99static inline int meta_type(struct meta_value *v)
 100{
 101        return TCF_META_TYPE(v->hdr.kind);
 102}
 103
 104#define META_COLLECTOR(FUNC) static void meta_##FUNC(struct sk_buff *skb, \
 105        struct tcf_pkt_info *info, struct meta_value *v, \
 106        struct meta_obj *dst, int *err)
 107
 108/**************************************************************************
 109 * System status & misc
 110 **************************************************************************/
 111
 112META_COLLECTOR(int_random)
 113{
 114        get_random_bytes(&dst->value, sizeof(dst->value));
 115}
 116
 117static inline unsigned long fixed_loadavg(int load)
 118{
 119        int rnd_load = load + (FIXED_1/200);
 120        int rnd_frac = ((rnd_load & (FIXED_1-1)) * 100) >> FSHIFT;
 121
 122        return ((rnd_load >> FSHIFT) * 100) + rnd_frac;
 123}
 124
 125META_COLLECTOR(int_loadavg_0)
 126{
 127        dst->value = fixed_loadavg(avenrun[0]);
 128}
 129
 130META_COLLECTOR(int_loadavg_1)
 131{
 132        dst->value = fixed_loadavg(avenrun[1]);
 133}
 134
 135META_COLLECTOR(int_loadavg_2)
 136{
 137        dst->value = fixed_loadavg(avenrun[2]);
 138}
 139
 140/**************************************************************************
 141 * Device names & indices
 142 **************************************************************************/
 143
 144static inline int int_dev(struct net_device *dev, struct meta_obj *dst)
 145{
 146        if (unlikely(dev == NULL))
 147                return -1;
 148
 149        dst->value = dev->ifindex;
 150        return 0;
 151}
 152
 153static inline int var_dev(struct net_device *dev, struct meta_obj *dst)
 154{
 155        if (unlikely(dev == NULL))
 156                return -1;
 157
 158        dst->value = (unsigned long) dev->name;
 159        dst->len = strlen(dev->name);
 160        return 0;
 161}
 162
 163META_COLLECTOR(int_dev)
 164{
 165        *err = int_dev(skb->dev, dst);
 166}
 167
 168META_COLLECTOR(var_dev)
 169{
 170        *err = var_dev(skb->dev, dst);
 171}
 172
 173/**************************************************************************
 174 * vlan tag
 175 **************************************************************************/
 176
 177META_COLLECTOR(int_vlan_tag)
 178{
 179        unsigned short uninitialized_var(tag);
 180        if (vlan_get_tag(skb, &tag) < 0)
 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
 223/**************************************************************************
 224 * Netfilter
 225 **************************************************************************/
 226
 227META_COLLECTOR(int_mark)
 228{
 229        dst->value = skb->mark;
 230}
 231
 232/**************************************************************************
 233 * Traffic Control
 234 **************************************************************************/
 235
 236META_COLLECTOR(int_tcindex)
 237{
 238        dst->value = skb->tc_index;
 239}
 240
 241/**************************************************************************
 242 * Routing
 243 **************************************************************************/
 244
 245META_COLLECTOR(int_rtclassid)
 246{
 247        if (unlikely(skb->dst == NULL))
 248                *err = -1;
 249        else
 250#ifdef CONFIG_NET_CLS_ROUTE
 251                dst->value = skb->dst->tclassid;
 252#else
 253                dst->value = 0;
 254#endif
 255}
 256
 257META_COLLECTOR(int_rtiif)
 258{
 259        if (unlikely(skb->rtable == NULL))
 260                *err = -1;
 261        else
 262                dst->value = skb->rtable->fl.iif;
 263}
 264
 265/**************************************************************************
 266 * Socket Attributes
 267 **************************************************************************/
 268
 269#define SKIP_NONLOCAL(skb)                      \
 270        if (unlikely(skb->sk == NULL)) {        \
 271                *err = -1;                      \
 272                return;                         \
 273        }
 274
 275META_COLLECTOR(int_sk_family)
 276{
 277        SKIP_NONLOCAL(skb);
 278        dst->value = skb->sk->sk_family;
 279}
 280
 281META_COLLECTOR(int_sk_state)
 282{
 283        SKIP_NONLOCAL(skb);
 284        dst->value = skb->sk->sk_state;
 285}
 286
 287META_COLLECTOR(int_sk_reuse)
 288{
 289        SKIP_NONLOCAL(skb);
 290        dst->value = skb->sk->sk_reuse;
 291}
 292
 293META_COLLECTOR(int_sk_bound_if)
 294{
 295        SKIP_NONLOCAL(skb);
 296        /* No error if bound_dev_if is 0, legal userspace check */
 297        dst->value = skb->sk->sk_bound_dev_if;
 298}
 299
 300META_COLLECTOR(var_sk_bound_if)
 301{
 302        SKIP_NONLOCAL(skb);
 303
 304         if (skb->sk->sk_bound_dev_if == 0) {
 305                dst->value = (unsigned long) "any";
 306                dst->len = 3;
 307         } else  {
 308                struct net_device *dev;
 309
 310                dev = dev_get_by_index(&init_net, skb->sk->sk_bound_dev_if);
 311                *err = var_dev(dev, dst);
 312                if (dev)
 313                        dev_put(dev);
 314         }
 315}
 316
 317META_COLLECTOR(int_sk_refcnt)
 318{
 319        SKIP_NONLOCAL(skb);
 320        dst->value = atomic_read(&skb->sk->sk_refcnt);
 321}
 322
 323META_COLLECTOR(int_sk_rcvbuf)
 324{
 325        SKIP_NONLOCAL(skb);
 326        dst->value = skb->sk->sk_rcvbuf;
 327}
 328
 329META_COLLECTOR(int_sk_shutdown)
 330{
 331        SKIP_NONLOCAL(skb);
 332        dst->value = skb->sk->sk_shutdown;
 333}
 334
 335META_COLLECTOR(int_sk_proto)
 336{
 337        SKIP_NONLOCAL(skb);
 338        dst->value = skb->sk->sk_protocol;
 339}
 340
 341META_COLLECTOR(int_sk_type)
 342{
 343        SKIP_NONLOCAL(skb);
 344        dst->value = skb->sk->sk_type;
 345}
 346
 347META_COLLECTOR(int_sk_rmem_alloc)
 348{
 349        SKIP_NONLOCAL(skb);
 350        dst->value = atomic_read(&skb->sk->sk_rmem_alloc);
 351}
 352
 353META_COLLECTOR(int_sk_wmem_alloc)
 354{
 355        SKIP_NONLOCAL(skb);
 356        dst->value = atomic_read(&skb->sk->sk_wmem_alloc);
 357}
 358
 359META_COLLECTOR(int_sk_omem_alloc)
 360{
 361        SKIP_NONLOCAL(skb);
 362        dst->value = atomic_read(&skb->sk->sk_omem_alloc);
 363}
 364
 365META_COLLECTOR(int_sk_rcv_qlen)
 366{
 367        SKIP_NONLOCAL(skb);
 368        dst->value = skb->sk->sk_receive_queue.qlen;
 369}
 370
 371META_COLLECTOR(int_sk_snd_qlen)
 372{
 373        SKIP_NONLOCAL(skb);
 374        dst->value = skb->sk->sk_write_queue.qlen;
 375}
 376
 377META_COLLECTOR(int_sk_wmem_queued)
 378{
 379        SKIP_NONLOCAL(skb);
 380        dst->value = skb->sk->sk_wmem_queued;
 381}
 382
 383META_COLLECTOR(int_sk_fwd_alloc)
 384{
 385        SKIP_NONLOCAL(skb);
 386        dst->value = skb->sk->sk_forward_alloc;
 387}
 388
 389META_COLLECTOR(int_sk_sndbuf)
 390{
 391        SKIP_NONLOCAL(skb);
 392        dst->value = skb->sk->sk_sndbuf;
 393}
 394
 395META_COLLECTOR(int_sk_alloc)
 396{
 397        SKIP_NONLOCAL(skb);
 398        dst->value = skb->sk->sk_allocation;
 399}
 400
 401META_COLLECTOR(int_sk_route_caps)
 402{
 403        SKIP_NONLOCAL(skb);
 404        dst->value = skb->sk->sk_route_caps;
 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{
 479        void            (*get)(struct sk_buff *, struct tcf_pkt_info *,
 480                               struct meta_value *, struct meta_obj *, int *);
 481};
 482
 483#define META_ID(name) TCF_META_ID_##name
 484#define META_FUNC(name) { .get = meta_##name }
 485
 486/* Meta value operations table listing all meta value collectors and
 487 * assigns them to a type and meta id. */
 488static struct meta_ops __meta_ops[TCF_META_TYPE_MAX+1][TCF_META_ID_MAX+1] = {
 489        [TCF_META_TYPE_VAR] = {
 490                [META_ID(DEV)]                  = META_FUNC(var_dev),
 491                [META_ID(SK_BOUND_IF)]          = META_FUNC(var_sk_bound_if),
 492        },
 493        [TCF_META_TYPE_INT] = {
 494                [META_ID(RANDOM)]               = META_FUNC(int_random),
 495                [META_ID(LOADAVG_0)]            = META_FUNC(int_loadavg_0),
 496                [META_ID(LOADAVG_1)]            = META_FUNC(int_loadavg_1),
 497                [META_ID(LOADAVG_2)]            = META_FUNC(int_loadavg_2),
 498                [META_ID(DEV)]                  = META_FUNC(int_dev),
 499                [META_ID(PRIORITY)]             = META_FUNC(int_priority),
 500                [META_ID(PROTOCOL)]             = META_FUNC(int_protocol),
 501                [META_ID(PKTTYPE)]              = META_FUNC(int_pkttype),
 502                [META_ID(PKTLEN)]               = META_FUNC(int_pktlen),
 503                [META_ID(DATALEN)]              = META_FUNC(int_datalen),
 504                [META_ID(MACLEN)]               = META_FUNC(int_maclen),
 505                [META_ID(NFMARK)]               = META_FUNC(int_mark),
 506                [META_ID(TCINDEX)]              = META_FUNC(int_tcindex),
 507                [META_ID(RTCLASSID)]            = META_FUNC(int_rtclassid),
 508                [META_ID(RTIIF)]                = META_FUNC(int_rtiif),
 509                [META_ID(SK_FAMILY)]            = META_FUNC(int_sk_family),
 510                [META_ID(SK_STATE)]             = META_FUNC(int_sk_state),
 511                [META_ID(SK_REUSE)]             = META_FUNC(int_sk_reuse),
 512                [META_ID(SK_BOUND_IF)]          = META_FUNC(int_sk_bound_if),
 513                [META_ID(SK_REFCNT)]            = META_FUNC(int_sk_refcnt),
 514                [META_ID(SK_RCVBUF)]            = META_FUNC(int_sk_rcvbuf),
 515                [META_ID(SK_SNDBUF)]            = META_FUNC(int_sk_sndbuf),
 516                [META_ID(SK_SHUTDOWN)]          = META_FUNC(int_sk_shutdown),
 517                [META_ID(SK_PROTO)]             = META_FUNC(int_sk_proto),
 518                [META_ID(SK_TYPE)]              = META_FUNC(int_sk_type),
 519                [META_ID(SK_RMEM_ALLOC)]        = META_FUNC(int_sk_rmem_alloc),
 520                [META_ID(SK_WMEM_ALLOC)]        = META_FUNC(int_sk_wmem_alloc),
 521                [META_ID(SK_OMEM_ALLOC)]        = META_FUNC(int_sk_omem_alloc),
 522                [META_ID(SK_WMEM_QUEUED)]       = META_FUNC(int_sk_wmem_queued),
 523                [META_ID(SK_RCV_QLEN)]          = META_FUNC(int_sk_rcv_qlen),
 524                [META_ID(SK_SND_QLEN)]          = META_FUNC(int_sk_snd_qlen),
 525                [META_ID(SK_ERR_QLEN)]          = META_FUNC(int_sk_err_qlen),
 526                [META_ID(SK_FORWARD_ALLOCS)]    = META_FUNC(int_sk_fwd_alloc),
 527                [META_ID(SK_ALLOCS)]            = META_FUNC(int_sk_alloc),
 528                [META_ID(SK_ROUTE_CAPS)]        = META_FUNC(int_sk_route_caps),
 529                [META_ID(SK_HASH)]              = META_FUNC(int_sk_hash),
 530                [META_ID(SK_LINGERTIME)]        = META_FUNC(int_sk_lingertime),
 531                [META_ID(SK_ACK_BACKLOG)]       = META_FUNC(int_sk_ack_bl),
 532                [META_ID(SK_MAX_ACK_BACKLOG)]   = META_FUNC(int_sk_max_ack_bl),
 533                [META_ID(SK_PRIO)]              = META_FUNC(int_sk_prio),
 534                [META_ID(SK_RCVLOWAT)]          = META_FUNC(int_sk_rcvlowat),
 535                [META_ID(SK_RCVTIMEO)]          = META_FUNC(int_sk_rcvtimeo),
 536                [META_ID(SK_SNDTIMEO)]          = META_FUNC(int_sk_sndtimeo),
 537                [META_ID(SK_SENDMSG_OFF)]       = META_FUNC(int_sk_sendmsg_off),
 538                [META_ID(SK_WRITE_PENDING)]     = META_FUNC(int_sk_write_pend),
 539                [META_ID(VLAN_TAG)]             = META_FUNC(int_vlan_tag),
 540        }
 541};
 542
 543static inline struct meta_ops * meta_ops(struct meta_value *val)
 544{
 545        return &__meta_ops[meta_type(val)][meta_id(val)];
 546}
 547
 548/**************************************************************************
 549 * Type specific operations for TCF_META_TYPE_VAR
 550 **************************************************************************/
 551
 552static int meta_var_compare(struct meta_obj *a, struct meta_obj *b)
 553{
 554        int r = a->len - b->len;
 555
 556        if (r == 0)
 557                r = memcmp((void *) a->value, (void *) b->value, a->len);
 558
 559        return r;
 560}
 561
 562static int meta_var_change(struct meta_value *dst, struct nlattr *nla)
 563{
 564        int len = nla_len(nla);
 565
 566        dst->val = (unsigned long)kmemdup(nla_data(nla), len, GFP_KERNEL);
 567        if (dst->val == 0UL)
 568                return -ENOMEM;
 569        dst->len = len;
 570        return 0;
 571}
 572
 573static void meta_var_destroy(struct meta_value *v)
 574{
 575        kfree((void *) v->val);
 576}
 577
 578static void meta_var_apply_extras(struct meta_value *v,
 579                                  struct meta_obj *dst)
 580{
 581        int shift = v->hdr.shift;
 582
 583        if (shift && shift < dst->len)
 584                dst->len -= shift;
 585}
 586
 587static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
 588{
 589        if (v->val && v->len)
 590                NLA_PUT(skb, tlv, v->len, (void *) v->val);
 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                NLA_PUT(skb, tlv, sizeof(unsigned long), &v->val);
 642        else if (v->len == sizeof(u32)) {
 643                NLA_PUT_U32(skb, tlv, v->val);
 644        }
 645
 646        return 0;
 647
 648nla_put_failure:
 649        return -1;
 650}
 651
 652/**************************************************************************
 653 * Type specific operations table
 654 **************************************************************************/
 655
 656struct meta_type_ops
 657{
 658        void    (*destroy)(struct meta_value *);
 659        int     (*compare)(struct meta_obj *, struct meta_obj *);
 660        int     (*change)(struct meta_value *, struct nlattr *);
 661        void    (*apply_extras)(struct meta_value *, struct meta_obj *);
 662        int     (*dump)(struct sk_buff *, struct meta_value *, int);
 663};
 664
 665static struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX+1] = {
 666        [TCF_META_TYPE_VAR] = {
 667                .destroy = meta_var_destroy,
 668                .compare = meta_var_compare,
 669                .change = meta_var_change,
 670                .apply_extras = meta_var_apply_extras,
 671                .dump = meta_var_dump
 672        },
 673        [TCF_META_TYPE_INT] = {
 674                .compare = meta_int_compare,
 675                .change = meta_int_change,
 676                .apply_extras = meta_int_apply_extras,
 677                .dump = meta_int_dump
 678        }
 679};
 680
 681static inline struct meta_type_ops * meta_type_ops(struct meta_value *v)
 682{
 683        return &__meta_type_ops[meta_type(v)];
 684}
 685
 686/**************************************************************************
 687 * Core
 688 **************************************************************************/
 689
 690static int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info,
 691                    struct meta_value *v, struct meta_obj *dst)
 692{
 693        int err = 0;
 694
 695        if (meta_id(v) == TCF_META_ID_VALUE) {
 696                dst->value = v->val;
 697                dst->len = v->len;
 698                return 0;
 699        }
 700
 701        meta_ops(v)->get(skb, info, v, dst, &err);
 702        if (err < 0)
 703                return err;
 704
 705        if (meta_type_ops(v)->apply_extras)
 706            meta_type_ops(v)->apply_extras(v, dst);
 707
 708        return 0;
 709}
 710
 711static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
 712                         struct tcf_pkt_info *info)
 713{
 714        int r;
 715        struct meta_match *meta = (struct meta_match *) m->data;
 716        struct meta_obj l_value, r_value;
 717
 718        if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 ||
 719            meta_get(skb, info, &meta->rvalue, &r_value) < 0)
 720                return 0;
 721
 722        r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value);
 723
 724        switch (meta->lvalue.hdr.op) {
 725                case TCF_EM_OPND_EQ:
 726                        return !r;
 727                case TCF_EM_OPND_LT:
 728                        return r < 0;
 729                case TCF_EM_OPND_GT:
 730                        return r > 0;
 731        }
 732
 733        return 0;
 734}
 735
 736static void meta_delete(struct meta_match *meta)
 737{
 738        if (meta) {
 739                struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
 740
 741                if (ops && ops->destroy) {
 742                        ops->destroy(&meta->lvalue);
 743                        ops->destroy(&meta->rvalue);
 744                }
 745        }
 746
 747        kfree(meta);
 748}
 749
 750static inline int meta_change_data(struct meta_value *dst, struct nlattr *nla)
 751{
 752        if (nla) {
 753                if (nla_len(nla) == 0)
 754                        return -EINVAL;
 755
 756                return meta_type_ops(dst)->change(dst, nla);
 757        }
 758
 759        return 0;
 760}
 761
 762static inline int meta_is_supported(struct meta_value *val)
 763{
 764        return (!meta_id(val) || meta_ops(val)->get);
 765}
 766
 767static const struct nla_policy meta_policy[TCA_EM_META_MAX + 1] = {
 768        [TCA_EM_META_HDR]       = { .len = sizeof(struct tcf_meta_hdr) },
 769};
 770
 771static int em_meta_change(struct tcf_proto *tp, void *data, int len,
 772                          struct tcf_ematch *m)
 773{
 774        int err;
 775        struct nlattr *tb[TCA_EM_META_MAX + 1];
 776        struct tcf_meta_hdr *hdr;
 777        struct meta_match *meta = NULL;
 778
 779        err = nla_parse(tb, TCA_EM_META_MAX, data, len, meta_policy);
 780        if (err < 0)
 781                goto errout;
 782
 783        err = -EINVAL;
 784        if (tb[TCA_EM_META_HDR] == NULL)
 785                goto errout;
 786        hdr = nla_data(tb[TCA_EM_META_HDR]);
 787
 788        if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) ||
 789            TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX ||
 790            TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX ||
 791            TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX)
 792                goto errout;
 793
 794        meta = kzalloc(sizeof(*meta), GFP_KERNEL);
 795        if (meta == NULL)
 796                goto errout;
 797
 798        memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));
 799        memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right));
 800
 801        if (!meta_is_supported(&meta->lvalue) ||
 802            !meta_is_supported(&meta->rvalue)) {
 803                err = -EOPNOTSUPP;
 804                goto errout;
 805        }
 806
 807        if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE]) < 0 ||
 808            meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE]) < 0)
 809                goto errout;
 810
 811        m->datalen = sizeof(*meta);
 812        m->data = (unsigned long) meta;
 813
 814        err = 0;
 815errout:
 816        if (err && meta)
 817                meta_delete(meta);
 818        return err;
 819}
 820
 821static void em_meta_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
 822{
 823        if (m)
 824                meta_delete((struct meta_match *) m->data);
 825}
 826
 827static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em)
 828{
 829        struct meta_match *meta = (struct meta_match *) em->data;
 830        struct tcf_meta_hdr hdr;
 831        struct meta_type_ops *ops;
 832
 833        memset(&hdr, 0, sizeof(hdr));
 834        memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left));
 835        memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right));
 836
 837        NLA_PUT(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr);
 838
 839        ops = meta_type_ops(&meta->lvalue);
 840        if (ops->dump(skb, &meta->lvalue, TCA_EM_META_LVALUE) < 0 ||
 841            ops->dump(skb, &meta->rvalue, TCA_EM_META_RVALUE) < 0)
 842                goto nla_put_failure;
 843
 844        return 0;
 845
 846nla_put_failure:
 847        return -1;
 848}
 849
 850static struct tcf_ematch_ops em_meta_ops = {
 851        .kind     = TCF_EM_META,
 852        .change   = em_meta_change,
 853        .match    = em_meta_match,
 854        .destroy  = em_meta_destroy,
 855        .dump     = em_meta_dump,
 856        .owner    = THIS_MODULE,
 857        .link     = LIST_HEAD_INIT(em_meta_ops.link)
 858};
 859
 860static int __init init_em_meta(void)
 861{
 862        return tcf_em_register(&em_meta_ops);
 863}
 864
 865static void __exit exit_em_meta(void)
 866{
 867        tcf_em_unregister(&em_meta_ops);
 868}
 869
 870MODULE_LICENSE("GPL");
 871
 872module_init(init_em_meta);
 873module_exit(exit_em_meta);
 874
 875MODULE_ALIAS_TCF_EMATCH(TCF_EM_META);
 876