linux/net/sched/cls_route.c
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   1/*
   2 * net/sched/cls_route.c        ROUTE4 classifier.
   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:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/slab.h>
  14#include <linux/types.h>
  15#include <linux/kernel.h>
  16#include <linux/string.h>
  17#include <linux/errno.h>
  18#include <linux/skbuff.h>
  19#include <net/dst.h>
  20#include <net/route.h>
  21#include <net/netlink.h>
  22#include <net/act_api.h>
  23#include <net/pkt_cls.h>
  24
  25/*
  26 * 1. For now we assume that route tags < 256.
  27 *    It allows to use direct table lookups, instead of hash tables.
  28 * 2. For now we assume that "from TAG" and "fromdev DEV" statements
  29 *    are mutually  exclusive.
  30 * 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
  31 */
  32
  33struct route4_fastmap {
  34        struct route4_filter    *filter;
  35        u32                     id;
  36        int                     iif;
  37};
  38
  39struct route4_head {
  40        struct route4_fastmap   fastmap[16];
  41        struct route4_bucket    *table[256 + 1];
  42};
  43
  44struct route4_bucket {
  45        /* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
  46        struct route4_filter    *ht[16 + 16 + 1];
  47};
  48
  49struct route4_filter {
  50        struct route4_filter    *next;
  51        u32                     id;
  52        int                     iif;
  53
  54        struct tcf_result       res;
  55        struct tcf_exts         exts;
  56        u32                     handle;
  57        struct route4_bucket    *bkt;
  58};
  59
  60#define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
  61
  62static const struct tcf_ext_map route_ext_map = {
  63        .police = TCA_ROUTE4_POLICE,
  64        .action = TCA_ROUTE4_ACT
  65};
  66
  67static inline int route4_fastmap_hash(u32 id, int iif)
  68{
  69        return id & 0xF;
  70}
  71
  72static void
  73route4_reset_fastmap(struct Qdisc *q, struct route4_head *head, u32 id)
  74{
  75        spinlock_t *root_lock = qdisc_root_sleeping_lock(q);
  76
  77        spin_lock_bh(root_lock);
  78        memset(head->fastmap, 0, sizeof(head->fastmap));
  79        spin_unlock_bh(root_lock);
  80}
  81
  82static void
  83route4_set_fastmap(struct route4_head *head, u32 id, int iif,
  84                   struct route4_filter *f)
  85{
  86        int h = route4_fastmap_hash(id, iif);
  87
  88        head->fastmap[h].id = id;
  89        head->fastmap[h].iif = iif;
  90        head->fastmap[h].filter = f;
  91}
  92
  93static inline int route4_hash_to(u32 id)
  94{
  95        return id & 0xFF;
  96}
  97
  98static inline int route4_hash_from(u32 id)
  99{
 100        return (id >> 16) & 0xF;
 101}
 102
 103static inline int route4_hash_iif(int iif)
 104{
 105        return 16 + ((iif >> 16) & 0xF);
 106}
 107
 108static inline int route4_hash_wild(void)
 109{
 110        return 32;
 111}
 112
 113#define ROUTE4_APPLY_RESULT()                                   \
 114{                                                               \
 115        *res = f->res;                                          \
 116        if (tcf_exts_is_available(&f->exts)) {                  \
 117                int r = tcf_exts_exec(skb, &f->exts, res);      \
 118                if (r < 0) {                                    \
 119                        dont_cache = 1;                         \
 120                        continue;                               \
 121                }                                               \
 122                return r;                                       \
 123        } else if (!dont_cache)                                 \
 124                route4_set_fastmap(head, id, iif, f);           \
 125        return 0;                                               \
 126}
 127
 128static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 129                           struct tcf_result *res)
 130{
 131        struct route4_head *head = (struct route4_head *)tp->root;
 132        struct dst_entry *dst;
 133        struct route4_bucket *b;
 134        struct route4_filter *f;
 135        u32 id, h;
 136        int iif, dont_cache = 0;
 137
 138        dst = skb_dst(skb);
 139        if (!dst)
 140                goto failure;
 141
 142        id = dst->tclassid;
 143        if (head == NULL)
 144                goto old_method;
 145
 146        iif = inet_iif(skb);
 147
 148        h = route4_fastmap_hash(id, iif);
 149        if (id == head->fastmap[h].id &&
 150            iif == head->fastmap[h].iif &&
 151            (f = head->fastmap[h].filter) != NULL) {
 152                if (f == ROUTE4_FAILURE)
 153                        goto failure;
 154
 155                *res = f->res;
 156                return 0;
 157        }
 158
 159        h = route4_hash_to(id);
 160
 161restart:
 162        b = head->table[h];
 163        if (b) {
 164                for (f = b->ht[route4_hash_from(id)]; f; f = f->next)
 165                        if (f->id == id)
 166                                ROUTE4_APPLY_RESULT();
 167
 168                for (f = b->ht[route4_hash_iif(iif)]; f; f = f->next)
 169                        if (f->iif == iif)
 170                                ROUTE4_APPLY_RESULT();
 171
 172                for (f = b->ht[route4_hash_wild()]; f; f = f->next)
 173                        ROUTE4_APPLY_RESULT();
 174
 175        }
 176        if (h < 256) {
 177                h = 256;
 178                id &= ~0xFFFF;
 179                goto restart;
 180        }
 181
 182        if (!dont_cache)
 183                route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
 184failure:
 185        return -1;
 186
 187old_method:
 188        if (id && (TC_H_MAJ(id) == 0 ||
 189                   !(TC_H_MAJ(id^tp->q->handle)))) {
 190                res->classid = id;
 191                res->class = 0;
 192                return 0;
 193        }
 194        return -1;
 195}
 196
 197static inline u32 to_hash(u32 id)
 198{
 199        u32 h = id & 0xFF;
 200
 201        if (id & 0x8000)
 202                h += 256;
 203        return h;
 204}
 205
 206static inline u32 from_hash(u32 id)
 207{
 208        id &= 0xFFFF;
 209        if (id == 0xFFFF)
 210                return 32;
 211        if (!(id & 0x8000)) {
 212                if (id > 255)
 213                        return 256;
 214                return id & 0xF;
 215        }
 216        return 16 + (id & 0xF);
 217}
 218
 219static unsigned long route4_get(struct tcf_proto *tp, u32 handle)
 220{
 221        struct route4_head *head = (struct route4_head *)tp->root;
 222        struct route4_bucket *b;
 223        struct route4_filter *f;
 224        unsigned int h1, h2;
 225
 226        if (!head)
 227                return 0;
 228
 229        h1 = to_hash(handle);
 230        if (h1 > 256)
 231                return 0;
 232
 233        h2 = from_hash(handle >> 16);
 234        if (h2 > 32)
 235                return 0;
 236
 237        b = head->table[h1];
 238        if (b) {
 239                for (f = b->ht[h2]; f; f = f->next)
 240                        if (f->handle == handle)
 241                                return (unsigned long)f;
 242        }
 243        return 0;
 244}
 245
 246static void route4_put(struct tcf_proto *tp, unsigned long f)
 247{
 248}
 249
 250static int route4_init(struct tcf_proto *tp)
 251{
 252        return 0;
 253}
 254
 255static void
 256route4_delete_filter(struct tcf_proto *tp, struct route4_filter *f)
 257{
 258        tcf_unbind_filter(tp, &f->res);
 259        tcf_exts_destroy(tp, &f->exts);
 260        kfree(f);
 261}
 262
 263static void route4_destroy(struct tcf_proto *tp)
 264{
 265        struct route4_head *head = tp->root;
 266        int h1, h2;
 267
 268        if (head == NULL)
 269                return;
 270
 271        for (h1 = 0; h1 <= 256; h1++) {
 272                struct route4_bucket *b;
 273
 274                b = head->table[h1];
 275                if (b) {
 276                        for (h2 = 0; h2 <= 32; h2++) {
 277                                struct route4_filter *f;
 278
 279                                while ((f = b->ht[h2]) != NULL) {
 280                                        b->ht[h2] = f->next;
 281                                        route4_delete_filter(tp, f);
 282                                }
 283                        }
 284                        kfree(b);
 285                }
 286        }
 287        kfree(head);
 288}
 289
 290static int route4_delete(struct tcf_proto *tp, unsigned long arg)
 291{
 292        struct route4_head *head = (struct route4_head *)tp->root;
 293        struct route4_filter **fp, *f = (struct route4_filter *)arg;
 294        unsigned int h = 0;
 295        struct route4_bucket *b;
 296        int i;
 297
 298        if (!head || !f)
 299                return -EINVAL;
 300
 301        h = f->handle;
 302        b = f->bkt;
 303
 304        for (fp = &b->ht[from_hash(h >> 16)]; *fp; fp = &(*fp)->next) {
 305                if (*fp == f) {
 306                        tcf_tree_lock(tp);
 307                        *fp = f->next;
 308                        tcf_tree_unlock(tp);
 309
 310                        route4_reset_fastmap(tp->q, head, f->id);
 311                        route4_delete_filter(tp, f);
 312
 313                        /* Strip tree */
 314
 315                        for (i = 0; i <= 32; i++)
 316                                if (b->ht[i])
 317                                        return 0;
 318
 319                        /* OK, session has no flows */
 320                        tcf_tree_lock(tp);
 321                        head->table[to_hash(h)] = NULL;
 322                        tcf_tree_unlock(tp);
 323
 324                        kfree(b);
 325                        return 0;
 326                }
 327        }
 328        return 0;
 329}
 330
 331static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
 332        [TCA_ROUTE4_CLASSID]    = { .type = NLA_U32 },
 333        [TCA_ROUTE4_TO]         = { .type = NLA_U32 },
 334        [TCA_ROUTE4_FROM]       = { .type = NLA_U32 },
 335        [TCA_ROUTE4_IIF]        = { .type = NLA_U32 },
 336};
 337
 338static int route4_set_parms(struct tcf_proto *tp, unsigned long base,
 339        struct route4_filter *f, u32 handle, struct route4_head *head,
 340        struct nlattr **tb, struct nlattr *est, int new)
 341{
 342        int err;
 343        u32 id = 0, to = 0, nhandle = 0x8000;
 344        struct route4_filter *fp;
 345        unsigned int h1;
 346        struct route4_bucket *b;
 347        struct tcf_exts e;
 348
 349        err = tcf_exts_validate(tp, tb, est, &e, &route_ext_map);
 350        if (err < 0)
 351                return err;
 352
 353        err = -EINVAL;
 354        if (tb[TCA_ROUTE4_TO]) {
 355                if (new && handle & 0x8000)
 356                        goto errout;
 357                to = nla_get_u32(tb[TCA_ROUTE4_TO]);
 358                if (to > 0xFF)
 359                        goto errout;
 360                nhandle = to;
 361        }
 362
 363        if (tb[TCA_ROUTE4_FROM]) {
 364                if (tb[TCA_ROUTE4_IIF])
 365                        goto errout;
 366                id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
 367                if (id > 0xFF)
 368                        goto errout;
 369                nhandle |= id << 16;
 370        } else if (tb[TCA_ROUTE4_IIF]) {
 371                id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
 372                if (id > 0x7FFF)
 373                        goto errout;
 374                nhandle |= (id | 0x8000) << 16;
 375        } else
 376                nhandle |= 0xFFFF << 16;
 377
 378        if (handle && new) {
 379                nhandle |= handle & 0x7F00;
 380                if (nhandle != handle)
 381                        goto errout;
 382        }
 383
 384        h1 = to_hash(nhandle);
 385        b = head->table[h1];
 386        if (!b) {
 387                err = -ENOBUFS;
 388                b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
 389                if (b == NULL)
 390                        goto errout;
 391
 392                tcf_tree_lock(tp);
 393                head->table[h1] = b;
 394                tcf_tree_unlock(tp);
 395        } else {
 396                unsigned int h2 = from_hash(nhandle >> 16);
 397
 398                err = -EEXIST;
 399                for (fp = b->ht[h2]; fp; fp = fp->next)
 400                        if (fp->handle == f->handle)
 401                                goto errout;
 402        }
 403
 404        tcf_tree_lock(tp);
 405        if (tb[TCA_ROUTE4_TO])
 406                f->id = to;
 407
 408        if (tb[TCA_ROUTE4_FROM])
 409                f->id = to | id<<16;
 410        else if (tb[TCA_ROUTE4_IIF])
 411                f->iif = id;
 412
 413        f->handle = nhandle;
 414        f->bkt = b;
 415        tcf_tree_unlock(tp);
 416
 417        if (tb[TCA_ROUTE4_CLASSID]) {
 418                f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
 419                tcf_bind_filter(tp, &f->res, base);
 420        }
 421
 422        tcf_exts_change(tp, &f->exts, &e);
 423
 424        return 0;
 425errout:
 426        tcf_exts_destroy(tp, &e);
 427        return err;
 428}
 429
 430static int route4_change(struct tcf_proto *tp, unsigned long base,
 431                       u32 handle,
 432                       struct nlattr **tca,
 433                       unsigned long *arg)
 434{
 435        struct route4_head *head = tp->root;
 436        struct route4_filter *f, *f1, **fp;
 437        struct route4_bucket *b;
 438        struct nlattr *opt = tca[TCA_OPTIONS];
 439        struct nlattr *tb[TCA_ROUTE4_MAX + 1];
 440        unsigned int h, th;
 441        u32 old_handle = 0;
 442        int err;
 443
 444        if (opt == NULL)
 445                return handle ? -EINVAL : 0;
 446
 447        err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy);
 448        if (err < 0)
 449                return err;
 450
 451        f = (struct route4_filter *)*arg;
 452        if (f) {
 453                if (f->handle != handle && handle)
 454                        return -EINVAL;
 455
 456                if (f->bkt)
 457                        old_handle = f->handle;
 458
 459                err = route4_set_parms(tp, base, f, handle, head, tb,
 460                        tca[TCA_RATE], 0);
 461                if (err < 0)
 462                        return err;
 463
 464                goto reinsert;
 465        }
 466
 467        err = -ENOBUFS;
 468        if (head == NULL) {
 469                head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
 470                if (head == NULL)
 471                        goto errout;
 472
 473                tcf_tree_lock(tp);
 474                tp->root = head;
 475                tcf_tree_unlock(tp);
 476        }
 477
 478        f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
 479        if (f == NULL)
 480                goto errout;
 481
 482        err = route4_set_parms(tp, base, f, handle, head, tb,
 483                tca[TCA_RATE], 1);
 484        if (err < 0)
 485                goto errout;
 486
 487reinsert:
 488        h = from_hash(f->handle >> 16);
 489        for (fp = &f->bkt->ht[h]; (f1 = *fp) != NULL; fp = &f1->next)
 490                if (f->handle < f1->handle)
 491                        break;
 492
 493        f->next = f1;
 494        tcf_tree_lock(tp);
 495        *fp = f;
 496
 497        if (old_handle && f->handle != old_handle) {
 498                th = to_hash(old_handle);
 499                h = from_hash(old_handle >> 16);
 500                b = head->table[th];
 501                if (b) {
 502                        for (fp = &b->ht[h]; *fp; fp = &(*fp)->next) {
 503                                if (*fp == f) {
 504                                        *fp = f->next;
 505                                        break;
 506                                }
 507                        }
 508                }
 509        }
 510        tcf_tree_unlock(tp);
 511
 512        route4_reset_fastmap(tp->q, head, f->id);
 513        *arg = (unsigned long)f;
 514        return 0;
 515
 516errout:
 517        kfree(f);
 518        return err;
 519}
 520
 521static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 522{
 523        struct route4_head *head = tp->root;
 524        unsigned int h, h1;
 525
 526        if (head == NULL)
 527                arg->stop = 1;
 528
 529        if (arg->stop)
 530                return;
 531
 532        for (h = 0; h <= 256; h++) {
 533                struct route4_bucket *b = head->table[h];
 534
 535                if (b) {
 536                        for (h1 = 0; h1 <= 32; h1++) {
 537                                struct route4_filter *f;
 538
 539                                for (f = b->ht[h1]; f; f = f->next) {
 540                                        if (arg->count < arg->skip) {
 541                                                arg->count++;
 542                                                continue;
 543                                        }
 544                                        if (arg->fn(tp, (unsigned long)f, arg) < 0) {
 545                                                arg->stop = 1;
 546                                                return;
 547                                        }
 548                                        arg->count++;
 549                                }
 550                        }
 551                }
 552        }
 553}
 554
 555static int route4_dump(struct tcf_proto *tp, unsigned long fh,
 556                       struct sk_buff *skb, struct tcmsg *t)
 557{
 558        struct route4_filter *f = (struct route4_filter *)fh;
 559        unsigned char *b = skb_tail_pointer(skb);
 560        struct nlattr *nest;
 561        u32 id;
 562
 563        if (f == NULL)
 564                return skb->len;
 565
 566        t->tcm_handle = f->handle;
 567
 568        nest = nla_nest_start(skb, TCA_OPTIONS);
 569        if (nest == NULL)
 570                goto nla_put_failure;
 571
 572        if (!(f->handle & 0x8000)) {
 573                id = f->id & 0xFF;
 574                if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
 575                        goto nla_put_failure;
 576        }
 577        if (f->handle & 0x80000000) {
 578                if ((f->handle >> 16) != 0xFFFF &&
 579                    nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
 580                        goto nla_put_failure;
 581        } else {
 582                id = f->id >> 16;
 583                if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
 584                        goto nla_put_failure;
 585        }
 586        if (f->res.classid &&
 587            nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
 588                goto nla_put_failure;
 589
 590        if (tcf_exts_dump(skb, &f->exts, &route_ext_map) < 0)
 591                goto nla_put_failure;
 592
 593        nla_nest_end(skb, nest);
 594
 595        if (tcf_exts_dump_stats(skb, &f->exts, &route_ext_map) < 0)
 596                goto nla_put_failure;
 597
 598        return skb->len;
 599
 600nla_put_failure:
 601        nlmsg_trim(skb, b);
 602        return -1;
 603}
 604
 605static struct tcf_proto_ops cls_route4_ops __read_mostly = {
 606        .kind           =       "route",
 607        .classify       =       route4_classify,
 608        .init           =       route4_init,
 609        .destroy        =       route4_destroy,
 610        .get            =       route4_get,
 611        .put            =       route4_put,
 612        .change         =       route4_change,
 613        .delete         =       route4_delete,
 614        .walk           =       route4_walk,
 615        .dump           =       route4_dump,
 616        .owner          =       THIS_MODULE,
 617};
 618
 619static int __init init_route4(void)
 620{
 621        return register_tcf_proto_ops(&cls_route4_ops);
 622}
 623
 624static void __exit exit_route4(void)
 625{
 626        unregister_tcf_proto_ops(&cls_route4_ops);
 627}
 628
 629module_init(init_route4)
 630module_exit(exit_route4)
 631MODULE_LICENSE("GPL");
 632
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