net/sched/cls_flow.c

   1 /*
   2  * net/sched/cls_flow.c         Generic flow classifier
   3  *
   4  * Copyright (c) 2007, 2008 Patrick McHardy <[email protected]>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/list.h>
  15 #include <linux/jhash.h>
  16 #include <linux/random.h>
  17 #include <linux/pkt_cls.h>
  18 #include <linux/skbuff.h>
  19 #include <linux/in.h>
  20 #include <linux/ip.h>
  21 #include <linux/ipv6.h>
  22 #include <linux/if_vlan.h>
  23 #include <linux/slab.h>
  24 #include <linux/module.h>
  25
  26 #include <net/pkt_cls.h>
  27 #include <net/ip.h>
  28 #include <net/route.h>
  29 #include <net/flow_keys.h>
  30
  31 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
  32 #include <net/netfilter/nf_conntrack.h>
  33 #endif
  34
  35 struct flow_head {
  36         struct list_head        filters;
  37 };
  38
  39 struct flow_filter {
  40         struct list_head        list;
  41         struct tcf_exts         exts;
  42         struct tcf_ematch_tree  ematches;
  43         struct timer_list       perturb_timer;
  44         u32                     perturb_period;
  45         u32                     handle;
  46
  47         u32                     nkeys;
  48         u32                     keymask;
  49         u32                     mode;
  50         u32                     mask;
  51         u32                     xor;
  52         u32                     rshift;
  53         u32                     addend;
  54         u32                     divisor;
  55         u32                     baseclass;
  56         u32                     hashrnd;
  57 };
  58
  59 static inline u32 addr_fold(void *addr)
  60 {
  61         unsigned long a = (unsigned long)addr;
  62
  63         return (a & 0xFFFFFFFF) ^ (BITS_PER_LONG > 32 ? a >> 32 : 0);
  64 }
  65
  66 static u32 flow_get_src(const struct sk_buff *skb, const struct flow_keys *flow)
  67 {
  68         if (flow->src)
  69                 return ntohl(flow->src);
  70         return addr_fold(skb->sk);
  71 }
  72
  73 static u32 flow_get_dst(const struct sk_buff *skb, const struct flow_keys *flow)
  74 {
  75         if (flow->dst)
  76                 return ntohl(flow->dst);
  77         return addr_fold(skb_dst(skb)) ^ (__force u16)skb->protocol;
  78 }
  79
  80 static u32 flow_get_proto(const struct sk_buff *skb, const struct flow_keys *flow)
  81 {
  82         return flow->ip_proto;
  83 }
  84
  85 static u32 flow_get_proto_src(const struct sk_buff *skb, const struct flow_keys *flow)
  86 {
  87         if (flow->ports)
  88                 return ntohs(flow->port16[0]);
  89
  90         return addr_fold(skb->sk);
  91 }
  92
  93 static u32 flow_get_proto_dst(const struct sk_buff *skb, const struct flow_keys *flow)
  94 {
  95         if (flow->ports)
  96                 return ntohs(flow->port16[1]);
  97
  98         return addr_fold(skb_dst(skb)) ^ (__force u16)skb->protocol;
  99 }
 100
 101 static u32 flow_get_iif(const struct sk_buff *skb)
 102 {
 103         return skb->skb_iif;
 104 }
 105
 106 static u32 flow_get_priority(const struct sk_buff *skb)
 107 {
 108         return skb->priority;
 109 }
 110
 111 static u32 flow_get_mark(const struct sk_buff *skb)
 112 {
 113         return skb->mark;
 114 }
 115
 116 static u32 flow_get_nfct(const struct sk_buff *skb)
 117 {
 118 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 119         return addr_fold(skb->nfct);
 120 #else
 121         return 0;
 122 #endif
 123 }
 124
 125 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 126 #define CTTUPLE(skb, member)                                            \
 127 ({                                                                      \
 128         enum ip_conntrack_info ctinfo;                                  \
 129         const struct nf_conn *ct = nf_ct_get(skb, &ctinfo);             \
 130         if (ct == NULL)                                                 \
 131                 goto fallback;                                          \
 132         ct->tuplehash[CTINFO2DIR(ctinfo)].tuple.member;                 \
 133 })
 134 #else
 135 #define CTTUPLE(skb, member)                                            \
 136 ({                                                                      \
 137         goto fallback;                                                  \
 138         0;                                                              \
 139 })
 140 #endif
 141
 142 static u32 flow_get_nfct_src(const struct sk_buff *skb, const struct flow_keys *flow)
 143 {
 144         switch (skb->protocol) {
 145         case htons(ETH_P_IP):
 146                 return ntohl(CTTUPLE(skb, src.u3.ip));
 147         case htons(ETH_P_IPV6):
 148                 return ntohl(CTTUPLE(skb, src.u3.ip6[3]));
 149         }
 150 fallback:
 151         return flow_get_src(skb, flow);
 152 }
 153
 154 static u32 flow_get_nfct_dst(const struct sk_buff *skb, const struct flow_keys *flow)
 155 {
 156         switch (skb->protocol) {
 157         case htons(ETH_P_IP):
 158                 return ntohl(CTTUPLE(skb, dst.u3.ip));
 159         case htons(ETH_P_IPV6):
 160                 return ntohl(CTTUPLE(skb, dst.u3.ip6[3]));
 161         }
 162 fallback:
 163         return flow_get_dst(skb, flow);
 164 }
 165
 166 static u32 flow_get_nfct_proto_src(const struct sk_buff *skb, const struct flow_keys *flow)
 167 {
 168         return ntohs(CTTUPLE(skb, src.u.all));
 169 fallback:
 170         return flow_get_proto_src(skb, flow);
 171 }
 172
 173 static u32 flow_get_nfct_proto_dst(const struct sk_buff *skb, const struct flow_keys *flow)
 174 {
 175         return ntohs(CTTUPLE(skb, dst.u.all));
 176 fallback:
 177         return flow_get_proto_dst(skb, flow);
 178 }
 179
 180 static u32 flow_get_rtclassid(const struct sk_buff *skb)
 181 {
 182 #ifdef CONFIG_IP_ROUTE_CLASSID
 183         if (skb_dst(skb))
 184                 return skb_dst(skb)->tclassid;
 185 #endif
 186         return 0;
 187 }
 188
 189 static u32 flow_get_skuid(const struct sk_buff *skb)
 190 {
 191         if (skb->sk && skb->sk->sk_socket && skb->sk->sk_socket->file) {
 192                 kuid_t skuid = skb->sk->sk_socket->file->f_cred->fsuid;
 193                 return from_kuid(&init_user_ns, skuid);
 194         }
 195         return 0;
 196 }
 197
 198 static u32 flow_get_skgid(const struct sk_buff *skb)
 199 {
 200         if (skb->sk && skb->sk->sk_socket && skb->sk->sk_socket->file) {
 201                 kgid_t skgid = skb->sk->sk_socket->file->f_cred->fsgid;
 202                 return from_kgid(&init_user_ns, skgid);
 203         }
 204         return 0;
 205 }
 206
 207 static u32 flow_get_vlan_tag(const struct sk_buff *skb)
 208 {
 209         u16 uninitialized_var(tag);
 210
 211         if (vlan_get_tag(skb, &tag) < 0)
 212                 return 0;
 213         return tag & VLAN_VID_MASK;
 214 }
 215
 216 static u32 flow_get_rxhash(struct sk_buff *skb)
 217 {
 218         return skb_get_hash(skb);
 219 }
 220
 221 static u32 flow_key_get(struct sk_buff *skb, int key, struct flow_keys *flow)
 222 {
 223         switch (key) {
 224         case FLOW_KEY_SRC:
 225                 return flow_get_src(skb, flow);
 226         case FLOW_KEY_DST:
 227                 return flow_get_dst(skb, flow);
 228         case FLOW_KEY_PROTO:
 229                 return flow_get_proto(skb, flow);
 230         case FLOW_KEY_PROTO_SRC:
 231                 return flow_get_proto_src(skb, flow);
 232         case FLOW_KEY_PROTO_DST:
 233                 return flow_get_proto_dst(skb, flow);
 234         case FLOW_KEY_IIF:
 235                 return flow_get_iif(skb);
 236         case FLOW_KEY_PRIORITY:
 237                 return flow_get_priority(skb);
 238         case FLOW_KEY_MARK:
 239                 return flow_get_mark(skb);
 240         case FLOW_KEY_NFCT:
 241                 return flow_get_nfct(skb);
 242         case FLOW_KEY_NFCT_SRC:
 243                 return flow_get_nfct_src(skb, flow);
 244         case FLOW_KEY_NFCT_DST:
 245                 return flow_get_nfct_dst(skb, flow);
 246         case FLOW_KEY_NFCT_PROTO_SRC:
 247                 return flow_get_nfct_proto_src(skb, flow);
 248         case FLOW_KEY_NFCT_PROTO_DST:
 249                 return flow_get_nfct_proto_dst(skb, flow);
 250         case FLOW_KEY_RTCLASSID:
 251                 return flow_get_rtclassid(skb);
 252         case FLOW_KEY_SKUID:
 253                 return flow_get_skuid(skb);
 254         case FLOW_KEY_SKGID:
 255                 return flow_get_skgid(skb);
 256         case FLOW_KEY_VLAN_TAG:
 257                 return flow_get_vlan_tag(skb);
 258         case FLOW_KEY_RXHASH:
 259                 return flow_get_rxhash(skb);
 260         default:
 261                 WARN_ON(1);
 262                 return 0;
 263         }
 264 }
 265
 266 #define FLOW_KEYS_NEEDED ((1 << FLOW_KEY_SRC) |                 \
 267                           (1 << FLOW_KEY_DST) |                 \
 268                           (1 << FLOW_KEY_PROTO) |               \
 269                           (1 << FLOW_KEY_PROTO_SRC) |           \
 270                           (1 << FLOW_KEY_PROTO_DST) |           \
 271                           (1 << FLOW_KEY_NFCT_SRC) |            \
 272                           (1 << FLOW_KEY_NFCT_DST) |            \
 273                           (1 << FLOW_KEY_NFCT_PROTO_SRC) |      \
 274                           (1 << FLOW_KEY_NFCT_PROTO_DST))
 275
 276 static int flow_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 277                          struct tcf_result *res)
 278 {
 279         struct flow_head *head = tp->root;
 280         struct flow_filter *f;
 281         u32 keymask;
 282         u32 classid;
 283         unsigned int n, key;
 284         int r;
 285
 286         list_for_each_entry(f, &head->filters, list) {
 287                 u32 keys[FLOW_KEY_MAX + 1];
 288                 struct flow_keys flow_keys;
 289
 290                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
 291                         continue;
 292
 293                 keymask = f->keymask;
 294                 if (keymask & FLOW_KEYS_NEEDED)
 295                         skb_flow_dissect(skb, &flow_keys);
 296
 297                 for (n = 0; n < f->nkeys; n++) {
 298                         key = ffs(keymask) - 1;
 299                         keymask &= ~(1 << key);
 300                         keys[n] = flow_key_get(skb, key, &flow_keys);
 301                 }
 302
 303                 if (f->mode == FLOW_MODE_HASH)
 304                         classid = jhash2(keys, f->nkeys, f->hashrnd);
 305                 else {
 306                         classid = keys[0];
 307                         classid = (classid & f->mask) ^ f->xor;
 308                         classid = (classid >> f->rshift) + f->addend;
 309                 }
 310
 311                 if (f->divisor)
 312                         classid %= f->divisor;
 313
 314                 res->class   = 0;
 315                 res->classid = TC_H_MAKE(f->baseclass, f->baseclass + classid);
 316
 317                 r = tcf_exts_exec(skb, &f->exts, res);
 318                 if (r < 0)
 319                         continue;
 320                 return r;
 321         }
 322         return -1;
 323 }
 324
 325 static void flow_perturbation(unsigned long arg)
 326 {
 327         struct flow_filter *f = (struct flow_filter *)arg;
 328
 329         get_random_bytes(&f->hashrnd, 4);
 330         if (f->perturb_period)
 331                 mod_timer(&f->perturb_timer, jiffies + f->perturb_period);
 332 }
 333
 334 static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = {
 335         [TCA_FLOW_KEYS]         = { .type = NLA_U32 },
 336         [TCA_FLOW_MODE]         = { .type = NLA_U32 },
 337         [TCA_FLOW_BASECLASS]    = { .type = NLA_U32 },
 338         [TCA_FLOW_RSHIFT]       = { .type = NLA_U32 },
 339         [TCA_FLOW_ADDEND]       = { .type = NLA_U32 },
 340         [TCA_FLOW_MASK]         = { .type = NLA_U32 },
 341         [TCA_FLOW_XOR]          = { .type = NLA_U32 },
 342         [TCA_FLOW_DIVISOR]      = { .type = NLA_U32 },
 343         [TCA_FLOW_ACT]          = { .type = NLA_NESTED },
 344         [TCA_FLOW_POLICE]       = { .type = NLA_NESTED },
 345         [TCA_FLOW_EMATCHES]     = { .type = NLA_NESTED },
 346         [TCA_FLOW_PERTURB]      = { .type = NLA_U32 },
 347 };
 348
 349 static int flow_change(struct net *net, struct sk_buff *in_skb,
 350                        struct tcf_proto *tp, unsigned long base,
 351                        u32 handle, struct nlattr **tca,
 352                        unsigned long *arg)
 353 {
 354         struct flow_head *head = tp->root;
 355         struct flow_filter *f;
 356         struct nlattr *opt = tca[TCA_OPTIONS];
 357         struct nlattr *tb[TCA_FLOW_MAX + 1];
 358         struct tcf_exts e;
 359         struct tcf_ematch_tree t;
 360         unsigned int nkeys = 0;
 361         unsigned int perturb_period = 0;
 362         u32 baseclass = 0;
 363         u32 keymask = 0;
 364         u32 mode;
 365         int err;
 366
 367         if (opt == NULL)
 368                 return -EINVAL;
 369
 370         err = nla_parse_nested(tb, TCA_FLOW_MAX, opt, flow_policy);
 371         if (err < 0)
 372                 return err;
 373
 374         if (tb[TCA_FLOW_BASECLASS]) {
 375                 baseclass = nla_get_u32(tb[TCA_FLOW_BASECLASS]);
 376                 if (TC_H_MIN(baseclass) == 0)
 377                         return -EINVAL;
 378         }
 379
 380         if (tb[TCA_FLOW_KEYS]) {
 381                 keymask = nla_get_u32(tb[TCA_FLOW_KEYS]);
 382
 383                 nkeys = hweight32(keymask);
 384                 if (nkeys == 0)
 385                         return -EINVAL;
 386
 387                 if (fls(keymask) - 1 > FLOW_KEY_MAX)
 388                         return -EOPNOTSUPP;
 389
 390                 if ((keymask & (FLOW_KEY_SKUID|FLOW_KEY_SKGID)) &&
 391                     sk_user_ns(NETLINK_CB(in_skb).sk) != &init_user_ns)
 392                         return -EOPNOTSUPP;
 393         }
 394
 395         tcf_exts_init(&e, TCA_FLOW_ACT, TCA_FLOW_POLICE);
 396         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e);
 397         if (err < 0)
 398                 return err;
 399
 400         err = tcf_em_tree_validate(tp, tb[TCA_FLOW_EMATCHES], &t);
 401         if (err < 0)
 402                 goto err1;
 403
 404         f = (struct flow_filter *)*arg;
 405         if (f != NULL) {
 406                 err = -EINVAL;
 407                 if (f->handle != handle && handle)
 408                         goto err2;
 409
 410                 mode = f->mode;
 411                 if (tb[TCA_FLOW_MODE])
 412                         mode = nla_get_u32(tb[TCA_FLOW_MODE]);
 413                 if (mode != FLOW_MODE_HASH && nkeys > 1)
 414                         goto err2;
 415
 416                 if (mode == FLOW_MODE_HASH)
 417                         perturb_period = f->perturb_period;
 418                 if (tb[TCA_FLOW_PERTURB]) {
 419                         if (mode != FLOW_MODE_HASH)
 420                                 goto err2;
 421                         perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ;
 422                 }
 423         } else {
 424                 err = -EINVAL;
 425                 if (!handle)
 426                         goto err2;
 427                 if (!tb[TCA_FLOW_KEYS])
 428                         goto err2;
 429
 430                 mode = FLOW_MODE_MAP;
 431                 if (tb[TCA_FLOW_MODE])
 432                         mode = nla_get_u32(tb[TCA_FLOW_MODE]);
 433                 if (mode != FLOW_MODE_HASH && nkeys > 1)
 434                         goto err2;
 435
 436                 if (tb[TCA_FLOW_PERTURB]) {
 437                         if (mode != FLOW_MODE_HASH)
 438                                 goto err2;
 439                         perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ;
 440                 }
 441
 442                 if (TC_H_MAJ(baseclass) == 0)
 443                         baseclass = TC_H_MAKE(tp->q->handle, baseclass);
 444                 if (TC_H_MIN(baseclass) == 0)
 445                         baseclass = TC_H_MAKE(baseclass, 1);
 446
 447                 err = -ENOBUFS;
 448                 f = kzalloc(sizeof(*f), GFP_KERNEL);
 449                 if (f == NULL)
 450                         goto err2;
 451
 452                 f->handle = handle;
 453                 f->mask   = ~0U;
 454                 tcf_exts_init(&f->exts, TCA_FLOW_ACT, TCA_FLOW_POLICE);
 455
 456                 get_random_bytes(&f->hashrnd, 4);
 457                 f->perturb_timer.function = flow_perturbation;
 458                 f->perturb_timer.data = (unsigned long)f;
 459                 init_timer_deferrable(&f->perturb_timer);
 460         }
 461
 462         tcf_exts_change(tp, &f->exts, &e);
 463         tcf_em_tree_change(tp, &f->ematches, &t);
 464
 465         tcf_tree_lock(tp);
 466
 467         if (tb[TCA_FLOW_KEYS]) {
 468                 f->keymask = keymask;
 469                 f->nkeys   = nkeys;
 470         }
 471
 472         f->mode = mode;
 473
 474         if (tb[TCA_FLOW_MASK])
 475                 f->mask = nla_get_u32(tb[TCA_FLOW_MASK]);
 476         if (tb[TCA_FLOW_XOR])
 477                 f->xor = nla_get_u32(tb[TCA_FLOW_XOR]);
 478         if (tb[TCA_FLOW_RSHIFT])
 479                 f->rshift = nla_get_u32(tb[TCA_FLOW_RSHIFT]);
 480         if (tb[TCA_FLOW_ADDEND])
 481                 f->addend = nla_get_u32(tb[TCA_FLOW_ADDEND]);
 482
 483         if (tb[TCA_FLOW_DIVISOR])
 484                 f->divisor = nla_get_u32(tb[TCA_FLOW_DIVISOR]);
 485         if (baseclass)
 486                 f->baseclass = baseclass;
 487
 488         f->perturb_period = perturb_period;
 489         del_timer(&f->perturb_timer);
 490         if (perturb_period)
 491                 mod_timer(&f->perturb_timer, jiffies + perturb_period);
 492
 493         if (*arg == 0)
 494                 list_add_tail(&f->list, &head->filters);
 495
 496         tcf_tree_unlock(tp);
 497
 498         *arg = (unsigned long)f;
 499         return 0;
 500
 501 err2:
 502         tcf_em_tree_destroy(tp, &t);
 503 err1:
 504         tcf_exts_destroy(tp, &e);
 505         return err;
 506 }
 507
 508 static void flow_destroy_filter(struct tcf_proto *tp, struct flow_filter *f)
 509 {
 510         del_timer_sync(&f->perturb_timer);
 511         tcf_exts_destroy(tp, &f->exts);
 512         tcf_em_tree_destroy(tp, &f->ematches);
 513         kfree(f);
 514 }
 515
 516 static int flow_delete(struct tcf_proto *tp, unsigned long arg)
 517 {
 518         struct flow_filter *f = (struct flow_filter *)arg;
 519
 520         tcf_tree_lock(tp);
 521         list_del(&f->list);
 522         tcf_tree_unlock(tp);
 523         flow_destroy_filter(tp, f);
 524         return 0;
 525 }
 526
 527 static int flow_init(struct tcf_proto *tp)
 528 {
 529         struct flow_head *head;
 530
 531         head = kzalloc(sizeof(*head), GFP_KERNEL);
 532         if (head == NULL)
 533                 return -ENOBUFS;
 534         INIT_LIST_HEAD(&head->filters);
 535         tp->root = head;
 536         return 0;
 537 }
 538
 539 static void flow_destroy(struct tcf_proto *tp)
 540 {
 541         struct flow_head *head = tp->root;
 542         struct flow_filter *f, *next;
 543
 544         list_for_each_entry_safe(f, next, &head->filters, list) {
 545                 list_del(&f->list);
 546                 flow_destroy_filter(tp, f);
 547         }
 548         kfree(head);
 549 }
 550
 551 static unsigned long flow_get(struct tcf_proto *tp, u32 handle)
 552 {
 553         struct flow_head *head = tp->root;
 554         struct flow_filter *f;
 555
 556         list_for_each_entry(f, &head->filters, list)
 557                 if (f->handle == handle)
 558                         return (unsigned long)f;
 559         return 0;
 560 }
 561
 562 static void flow_put(struct tcf_proto *tp, unsigned long f)
 563 {
 564 }
 565
 566 static int flow_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
 567                      struct sk_buff *skb, struct tcmsg *t)
 568 {
 569         struct flow_filter *f = (struct flow_filter *)fh;
 570         struct nlattr *nest;
 571
 572         if (f == NULL)
 573                 return skb->len;
 574
 575         t->tcm_handle = f->handle;
 576
 577         nest = nla_nest_start(skb, TCA_OPTIONS);
 578         if (nest == NULL)
 579                 goto nla_put_failure;
 580
 581         if (nla_put_u32(skb, TCA_FLOW_KEYS, f->keymask) ||
 582             nla_put_u32(skb, TCA_FLOW_MODE, f->mode))
 583                 goto nla_put_failure;
 584
 585         if (f->mask != ~0 || f->xor != 0) {
 586                 if (nla_put_u32(skb, TCA_FLOW_MASK, f->mask) ||
 587                     nla_put_u32(skb, TCA_FLOW_XOR, f->xor))
 588                         goto nla_put_failure;
 589         }
 590         if (f->rshift &&
 591             nla_put_u32(skb, TCA_FLOW_RSHIFT, f->rshift))
 592                 goto nla_put_failure;
 593         if (f->addend &&
 594             nla_put_u32(skb, TCA_FLOW_ADDEND, f->addend))
 595                 goto nla_put_failure;
 596
 597         if (f->divisor &&
 598             nla_put_u32(skb, TCA_FLOW_DIVISOR, f->divisor))
 599                 goto nla_put_failure;
 600         if (f->baseclass &&
 601             nla_put_u32(skb, TCA_FLOW_BASECLASS, f->baseclass))
 602                 goto nla_put_failure;
 603
 604         if (f->perturb_period &&
 605             nla_put_u32(skb, TCA_FLOW_PERTURB, f->perturb_period / HZ))
 606                 goto nla_put_failure;
 607
 608         if (tcf_exts_dump(skb, &f->exts) < 0)
 609                 goto nla_put_failure;
 610 #ifdef CONFIG_NET_EMATCH
 611         if (f->ematches.hdr.nmatches &&
 612             tcf_em_tree_dump(skb, &f->ematches, TCA_FLOW_EMATCHES) < 0)
 613                 goto nla_put_failure;
 614 #endif
 615         nla_nest_end(skb, nest);
 616
 617         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 618                 goto nla_put_failure;
 619
 620         return skb->len;
 621
 622 nla_put_failure:
 623         nlmsg_trim(skb, nest);
 624         return -1;
 625 }
 626
 627 static void flow_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 628 {
 629         struct flow_head *head = tp->root;
 630         struct flow_filter *f;
 631
 632         list_for_each_entry(f, &head->filters, list) {
 633                 if (arg->count < arg->skip)
 634                         goto skip;
 635                 if (arg->fn(tp, (unsigned long)f, arg) < 0) {
 636                         arg->stop = 1;
 637                         break;
 638                 }
 639 skip:
 640                 arg->count++;
 641         }
 642 }
 643
 644 static struct tcf_proto_ops cls_flow_ops __read_mostly = {
 645         .kind           = "flow",
 646         .classify       = flow_classify,
 647         .init           = flow_init,
 648         .destroy        = flow_destroy,
 649         .change         = flow_change,
 650         .delete         = flow_delete,
 651         .get            = flow_get,
 652         .put            = flow_put,
 653         .dump           = flow_dump,
 654         .walk           = flow_walk,
 655         .owner          = THIS_MODULE,
 656 };
 657
 658 static int __init cls_flow_init(void)
 659 {
 660         return register_tcf_proto_ops(&cls_flow_ops);
 661 }
 662
 663 static void __exit cls_flow_exit(void)
 664 {
 665         unregister_tcf_proto_ops(&cls_flow_ops);
 666 }
 667
 668 module_init(cls_flow_init);
 669 module_exit(cls_flow_exit);
 670
 671 MODULE_LICENSE("GPL");
 672 MODULE_AUTHOR("Patrick McHardy <[email protected]>");
 673 MODULE_DESCRIPTION("TC flow classifier");