net/sched/cls_flow.c

   1 /*
   2  * net/sched/cls_flow.c         Generic flow classifier
   3  *
   4  * Copyright (c) 2007, 2008 Patrick McHardy <kaber@trash.net>
   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
  25 #include <net/pkt_cls.h>
  26 #include <net/ip.h>
  27 #include <net/route.h>
  28 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
  29 #include <net/netfilter/nf_conntrack.h>
  30 #endif
  31
  32 struct flow_head {
  33         struct list_head        filters;
  34 };
  35
  36 struct flow_filter {
  37         struct list_head        list;
  38         struct tcf_exts         exts;
  39         struct tcf_ematch_tree  ematches;
  40         struct timer_list       perturb_timer;
  41         u32                     perturb_period;
  42         u32                     handle;
  43
  44         u32                     nkeys;
  45         u32                     keymask;
  46         u32                     mode;
  47         u32                     mask;
  48         u32                     xor;
  49         u32                     rshift;
  50         u32                     addend;
  51         u32                     divisor;
  52         u32                     baseclass;
  53         u32                     hashrnd;
  54 };
  55
  56 static const struct tcf_ext_map flow_ext_map = {
  57         .action = TCA_FLOW_ACT,
  58         .police = TCA_FLOW_POLICE,
  59 };
  60
  61 static inline u32 addr_fold(void *addr)
  62 {
  63         unsigned long a = (unsigned long)addr;
  64
  65         return (a & 0xFFFFFFFF) ^ (BITS_PER_LONG > 32 ? a >> 32 : 0);
  66 }
  67
  68 static u32 flow_get_src(const struct sk_buff *skb)
  69 {
  70         switch (skb->protocol) {
  71         case htons(ETH_P_IP):
  72                 return ntohl(ip_hdr(skb)->saddr);
  73         case htons(ETH_P_IPV6):
  74                 return ntohl(ipv6_hdr(skb)->saddr.s6_addr32[3]);
  75         default:
  76                 return addr_fold(skb->sk);
  77         }
  78 }
  79
  80 static u32 flow_get_dst(const struct sk_buff *skb)
  81 {
  82         switch (skb->protocol) {
  83         case htons(ETH_P_IP):
  84                 return ntohl(ip_hdr(skb)->daddr);
  85         case htons(ETH_P_IPV6):
  86                 return ntohl(ipv6_hdr(skb)->daddr.s6_addr32[3]);
  87         default:
  88                 return addr_fold(skb_dst(skb)) ^ (__force u16)skb->protocol;
  89         }
  90 }
  91
  92 static u32 flow_get_proto(const struct sk_buff *skb)
  93 {
  94         switch (skb->protocol) {
  95         case htons(ETH_P_IP):
  96                 return ip_hdr(skb)->protocol;
  97         case htons(ETH_P_IPV6):
  98                 return ipv6_hdr(skb)->nexthdr;
  99         default:
 100                 return 0;
 101         }
 102 }
 103
 104 static int has_ports(u8 protocol)
 105 {
 106         switch (protocol) {
 107         case IPPROTO_TCP:
 108         case IPPROTO_UDP:
 109         case IPPROTO_UDPLITE:
 110         case IPPROTO_SCTP:
 111         case IPPROTO_DCCP:
 112         case IPPROTO_ESP:
 113                 return 1;
 114         default:
 115                 return 0;
 116         }
 117 }
 118
 119 static u32 flow_get_proto_src(const struct sk_buff *skb)
 120 {
 121         u32 res = 0;
 122
 123         switch (skb->protocol) {
 124         case htons(ETH_P_IP): {
 125                 struct iphdr *iph = ip_hdr(skb);
 126
 127                 if (!(iph->frag_off&htons(IP_MF|IP_OFFSET)) &&
 128                     has_ports(iph->protocol))
 129                         res = ntohs(*(__be16 *)((void *)iph + iph->ihl * 4));
 130                 break;
 131         }
 132         case htons(ETH_P_IPV6): {
 133                 struct ipv6hdr *iph = ipv6_hdr(skb);
 134
 135                 if (has_ports(iph->nexthdr))
 136                         res = ntohs(*(__be16 *)&iph[1]);
 137                 break;
 138         }
 139         default:
 140                 res = addr_fold(skb->sk);
 141         }
 142
 143         return res;
 144 }
 145
 146 static u32 flow_get_proto_dst(const struct sk_buff *skb)
 147 {
 148         u32 res = 0;
 149
 150         switch (skb->protocol) {
 151         case htons(ETH_P_IP): {
 152                 struct iphdr *iph = ip_hdr(skb);
 153
 154                 if (!(iph->frag_off&htons(IP_MF|IP_OFFSET)) &&
 155                     has_ports(iph->protocol))
 156                         res = ntohs(*(__be16 *)((void *)iph + iph->ihl * 4 + 2));
 157                 break;
 158         }
 159         case htons(ETH_P_IPV6): {
 160                 struct ipv6hdr *iph = ipv6_hdr(skb);
 161
 162                 if (has_ports(iph->nexthdr))
 163                         res = ntohs(*(__be16 *)((void *)&iph[1] + 2));
 164                 break;
 165         }
 166         default:
 167                 res = addr_fold(skb_dst(skb)) ^ (__force u16)skb->protocol;
 168         }
 169
 170         return res;
 171 }
 172
 173 static u32 flow_get_iif(const struct sk_buff *skb)
 174 {
 175         return skb->skb_iif;
 176 }
 177
 178 static u32 flow_get_priority(const struct sk_buff *skb)
 179 {
 180         return skb->priority;
 181 }
 182
 183 static u32 flow_get_mark(const struct sk_buff *skb)
 184 {
 185         return skb->mark;
 186 }
 187
 188 static u32 flow_get_nfct(const struct sk_buff *skb)
 189 {
 190 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 191         return addr_fold(skb->nfct);
 192 #else
 193         return 0;
 194 #endif
 195 }
 196
 197 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 198 #define CTTUPLE(skb, member)                                            \
 199 ({                                                                      \
 200         enum ip_conntrack_info ctinfo;                                  \
 201         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);                   \
 202         if (ct == NULL)                                                 \
 203                 goto fallback;                                          \
 204         ct->tuplehash[CTINFO2DIR(ctinfo)].tuple.member;                 \
 205 })
 206 #else
 207 #define CTTUPLE(skb, member)                                            \
 208 ({                                                                      \
 209         goto fallback;                                                  \
 210         0;                                                              \
 211 })
 212 #endif
 213
 214 static u32 flow_get_nfct_src(const struct sk_buff *skb)
 215 {
 216         switch (skb->protocol) {
 217         case htons(ETH_P_IP):
 218                 return ntohl(CTTUPLE(skb, src.u3.ip));
 219         case htons(ETH_P_IPV6):
 220                 return ntohl(CTTUPLE(skb, src.u3.ip6[3]));
 221         }
 222 fallback:
 223         return flow_get_src(skb);
 224 }
 225
 226 static u32 flow_get_nfct_dst(const struct sk_buff *skb)
 227 {
 228         switch (skb->protocol) {
 229         case htons(ETH_P_IP):
 230                 return ntohl(CTTUPLE(skb, dst.u3.ip));
 231         case htons(ETH_P_IPV6):
 232                 return ntohl(CTTUPLE(skb, dst.u3.ip6[3]));
 233         }
 234 fallback:
 235         return flow_get_dst(skb);
 236 }
 237
 238 static u32 flow_get_nfct_proto_src(const struct sk_buff *skb)
 239 {
 240         return ntohs(CTTUPLE(skb, src.u.all));
 241 fallback:
 242         return flow_get_proto_src(skb);
 243 }
 244
 245 static u32 flow_get_nfct_proto_dst(const struct sk_buff *skb)
 246 {
 247         return ntohs(CTTUPLE(skb, dst.u.all));
 248 fallback:
 249         return flow_get_proto_dst(skb);
 250 }
 251
 252 static u32 flow_get_rtclassid(const struct sk_buff *skb)
 253 {
 254 #ifdef CONFIG_NET_CLS_ROUTE
 255         if (skb_dst(skb))
 256                 return skb_dst(skb)->tclassid;
 257 #endif
 258         return 0;
 259 }
 260
 261 static u32 flow_get_skuid(const struct sk_buff *skb)
 262 {
 263         if (skb->sk && skb->sk->sk_socket && skb->sk->sk_socket->file)
 264                 return skb->sk->sk_socket->file->f_cred->fsuid;
 265         return 0;
 266 }
 267
 268 static u32 flow_get_skgid(const struct sk_buff *skb)
 269 {
 270         if (skb->sk && skb->sk->sk_socket && skb->sk->sk_socket->file)
 271                 return skb->sk->sk_socket->file->f_cred->fsgid;
 272         return 0;
 273 }
 274
 275 static u32 flow_get_vlan_tag(const struct sk_buff *skb)
 276 {
 277         u16 uninitialized_var(tag);
 278
 279         if (vlan_get_tag(skb, &tag) < 0)
 280                 return 0;
 281         return tag & VLAN_VID_MASK;
 282 }
 283
 284 static u32 flow_key_get(const struct sk_buff *skb, int key)
 285 {
 286         switch (key) {
 287         case FLOW_KEY_SRC:
 288                 return flow_get_src(skb);
 289         case FLOW_KEY_DST:
 290                 return flow_get_dst(skb);
 291         case FLOW_KEY_PROTO:
 292                 return flow_get_proto(skb);
 293         case FLOW_KEY_PROTO_SRC:
 294                 return flow_get_proto_src(skb);
 295         case FLOW_KEY_PROTO_DST:
 296                 return flow_get_proto_dst(skb);
 297         case FLOW_KEY_IIF:
 298                 return flow_get_iif(skb);
 299         case FLOW_KEY_PRIORITY:
 300                 return flow_get_priority(skb);
 301         case FLOW_KEY_MARK:
 302                 return flow_get_mark(skb);
 303         case FLOW_KEY_NFCT:
 304                 return flow_get_nfct(skb);
 305         case FLOW_KEY_NFCT_SRC:
 306                 return flow_get_nfct_src(skb);
 307         case FLOW_KEY_NFCT_DST:
 308                 return flow_get_nfct_dst(skb);
 309         case FLOW_KEY_NFCT_PROTO_SRC:
 310                 return flow_get_nfct_proto_src(skb);
 311         case FLOW_KEY_NFCT_PROTO_DST:
 312                 return flow_get_nfct_proto_dst(skb);
 313         case FLOW_KEY_RTCLASSID:
 314                 return flow_get_rtclassid(skb);
 315         case FLOW_KEY_SKUID:
 316                 return flow_get_skuid(skb);
 317         case FLOW_KEY_SKGID:
 318                 return flow_get_skgid(skb);
 319         case FLOW_KEY_VLAN_TAG:
 320                 return flow_get_vlan_tag(skb);
 321         default:
 322                 WARN_ON(1);
 323                 return 0;
 324         }
 325 }
 326
 327 static int flow_classify(struct sk_buff *skb, struct tcf_proto *tp,
 328                          struct tcf_result *res)
 329 {
 330         struct flow_head *head = tp->root;
 331         struct flow_filter *f;
 332         u32 keymask;
 333         u32 classid;
 334         unsigned int n, key;
 335         int r;
 336
 337         list_for_each_entry(f, &head->filters, list) {
 338                 u32 keys[f->nkeys];
 339
 340                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
 341                         continue;
 342
 343                 keymask = f->keymask;
 344
 345                 for (n = 0; n < f->nkeys; n++) {
 346                         key = ffs(keymask) - 1;
 347                         keymask &= ~(1 << key);
 348                         keys[n] = flow_key_get(skb, key);
 349                 }
 350
 351                 if (f->mode == FLOW_MODE_HASH)
 352                         classid = jhash2(keys, f->nkeys, f->hashrnd);
 353                 else {
 354                         classid = keys[0];
 355                         classid = (classid & f->mask) ^ f->xor;
 356                         classid = (classid >> f->rshift) + f->addend;
 357                 }
 358
 359                 if (f->divisor)
 360                         classid %= f->divisor;
 361
 362                 res->class   = 0;
 363                 res->classid = TC_H_MAKE(f->baseclass, f->baseclass + classid);
 364
 365                 r = tcf_exts_exec(skb, &f->exts, res);
 366                 if (r < 0)
 367                         continue;
 368                 return r;
 369         }
 370         return -1;
 371 }
 372
 373 static void flow_perturbation(unsigned long arg)
 374 {
 375         struct flow_filter *f = (struct flow_filter *)arg;
 376
 377         get_random_bytes(&f->hashrnd, 4);
 378         if (f->perturb_period)
 379                 mod_timer(&f->perturb_timer, jiffies + f->perturb_period);
 380 }
 381
 382 static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = {
 383         [TCA_FLOW_KEYS]         = { .type = NLA_U32 },
 384         [TCA_FLOW_MODE]         = { .type = NLA_U32 },
 385         [TCA_FLOW_BASECLASS]    = { .type = NLA_U32 },
 386         [TCA_FLOW_RSHIFT]       = { .type = NLA_U32 },
 387         [TCA_FLOW_ADDEND]       = { .type = NLA_U32 },
 388         [TCA_FLOW_MASK]         = { .type = NLA_U32 },
 389         [TCA_FLOW_XOR]          = { .type = NLA_U32 },
 390         [TCA_FLOW_DIVISOR]      = { .type = NLA_U32 },
 391         [TCA_FLOW_ACT]          = { .type = NLA_NESTED },
 392         [TCA_FLOW_POLICE]       = { .type = NLA_NESTED },
 393         [TCA_FLOW_EMATCHES]     = { .type = NLA_NESTED },
 394         [TCA_FLOW_PERTURB]      = { .type = NLA_U32 },
 395 };
 396
 397 static int flow_change(struct tcf_proto *tp, unsigned long base,
 398                        u32 handle, struct nlattr **tca,
 399                        unsigned long *arg)
 400 {
 401         struct flow_head *head = tp->root;
 402         struct flow_filter *f;
 403         struct nlattr *opt = tca[TCA_OPTIONS];
 404         struct nlattr *tb[TCA_FLOW_MAX + 1];
 405         struct tcf_exts e;
 406         struct tcf_ematch_tree t;
 407         unsigned int nkeys = 0;
 408         unsigned int perturb_period = 0;
 409         u32 baseclass = 0;
 410         u32 keymask = 0;
 411         u32 mode;
 412         int err;
 413
 414         if (opt == NULL)
 415                 return -EINVAL;
 416
 417         err = nla_parse_nested(tb, TCA_FLOW_MAX, opt, flow_policy);
 418         if (err < 0)
 419                 return err;
 420
 421         if (tb[TCA_FLOW_BASECLASS]) {
 422                 baseclass = nla_get_u32(tb[TCA_FLOW_BASECLASS]);
 423                 if (TC_H_MIN(baseclass) == 0)
 424                         return -EINVAL;
 425         }
 426
 427         if (tb[TCA_FLOW_KEYS]) {
 428                 keymask = nla_get_u32(tb[TCA_FLOW_KEYS]);
 429
 430                 nkeys = hweight32(keymask);
 431                 if (nkeys == 0)
 432                         return -EINVAL;
 433
 434                 if (fls(keymask) - 1 > FLOW_KEY_MAX)
 435                         return -EOPNOTSUPP;
 436         }
 437
 438         err = tcf_exts_validate(tp, tb, tca[TCA_RATE], &e, &flow_ext_map);
 439         if (err < 0)
 440                 return err;
 441
 442         err = tcf_em_tree_validate(tp, tb[TCA_FLOW_EMATCHES], &t);
 443         if (err < 0)
 444                 goto err1;
 445
 446         f = (struct flow_filter *)*arg;
 447         if (f != NULL) {
 448                 err = -EINVAL;
 449                 if (f->handle != handle && handle)
 450                         goto err2;
 451
 452                 mode = f->mode;
 453                 if (tb[TCA_FLOW_MODE])
 454                         mode = nla_get_u32(tb[TCA_FLOW_MODE]);
 455                 if (mode != FLOW_MODE_HASH && nkeys > 1)
 456                         goto err2;
 457
 458                 if (mode == FLOW_MODE_HASH)
 459                         perturb_period = f->perturb_period;
 460                 if (tb[TCA_FLOW_PERTURB]) {
 461                         if (mode != FLOW_MODE_HASH)
 462                                 goto err2;
 463                         perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ;
 464                 }
 465         } else {
 466                 err = -EINVAL;
 467                 if (!handle)
 468                         goto err2;
 469                 if (!tb[TCA_FLOW_KEYS])
 470                         goto err2;
 471
 472                 mode = FLOW_MODE_MAP;
 473                 if (tb[TCA_FLOW_MODE])
 474                         mode = nla_get_u32(tb[TCA_FLOW_MODE]);
 475                 if (mode != FLOW_MODE_HASH && nkeys > 1)
 476                         goto err2;
 477
 478                 if (tb[TCA_FLOW_PERTURB]) {
 479                         if (mode != FLOW_MODE_HASH)
 480                                 goto err2;
 481                         perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ;
 482                 }
 483
 484                 if (TC_H_MAJ(baseclass) == 0)
 485                         baseclass = TC_H_MAKE(tp->q->handle, baseclass);
 486                 if (TC_H_MIN(baseclass) == 0)
 487                         baseclass = TC_H_MAKE(baseclass, 1);
 488
 489                 err = -ENOBUFS;
 490                 f = kzalloc(sizeof(*f), GFP_KERNEL);
 491                 if (f == NULL)
 492                         goto err2;
 493
 494                 f->handle = handle;
 495                 f->mask   = ~0U;
 496
 497                 get_random_bytes(&f->hashrnd, 4);
 498                 f->perturb_timer.function = flow_perturbation;
 499                 f->perturb_timer.data = (unsigned long)f;
 500                 init_timer_deferrable(&f->perturb_timer);
 501         }
 502
 503         tcf_exts_change(tp, &f->exts, &e);
 504         tcf_em_tree_change(tp, &f->ematches, &t);
 505
 506         tcf_tree_lock(tp);
 507
 508         if (tb[TCA_FLOW_KEYS]) {
 509                 f->keymask = keymask;
 510                 f->nkeys   = nkeys;
 511         }
 512
 513         f->mode = mode;
 514
 515         if (tb[TCA_FLOW_MASK])
 516                 f->mask = nla_get_u32(tb[TCA_FLOW_MASK]);
 517         if (tb[TCA_FLOW_XOR])
 518                 f->xor = nla_get_u32(tb[TCA_FLOW_XOR]);
 519         if (tb[TCA_FLOW_RSHIFT])
 520                 f->rshift = nla_get_u32(tb[TCA_FLOW_RSHIFT]);
 521         if (tb[TCA_FLOW_ADDEND])
 522                 f->addend = nla_get_u32(tb[TCA_FLOW_ADDEND]);
 523
 524         if (tb[TCA_FLOW_DIVISOR])
 525                 f->divisor = nla_get_u32(tb[TCA_FLOW_DIVISOR]);
 526         if (baseclass)
 527                 f->baseclass = baseclass;
 528
 529         f->perturb_period = perturb_period;
 530         del_timer(&f->perturb_timer);
 531         if (perturb_period)
 532                 mod_timer(&f->perturb_timer, jiffies + perturb_period);
 533
 534         if (*arg == 0)
 535                 list_add_tail(&f->list, &head->filters);
 536
 537         tcf_tree_unlock(tp);
 538
 539         *arg = (unsigned long)f;
 540         return 0;
 541
 542 err2:
 543         tcf_em_tree_destroy(tp, &t);
 544 err1:
 545         tcf_exts_destroy(tp, &e);
 546         return err;
 547 }
 548
 549 static void flow_destroy_filter(struct tcf_proto *tp, struct flow_filter *f)
 550 {
 551         del_timer_sync(&f->perturb_timer);
 552         tcf_exts_destroy(tp, &f->exts);
 553         tcf_em_tree_destroy(tp, &f->ematches);
 554         kfree(f);
 555 }
 556
 557 static int flow_delete(struct tcf_proto *tp, unsigned long arg)
 558 {
 559         struct flow_filter *f = (struct flow_filter *)arg;
 560
 561         tcf_tree_lock(tp);
 562         list_del(&f->list);
 563         tcf_tree_unlock(tp);
 564         flow_destroy_filter(tp, f);
 565         return 0;
 566 }
 567
 568 static int flow_init(struct tcf_proto *tp)
 569 {
 570         struct flow_head *head;
 571
 572         head = kzalloc(sizeof(*head), GFP_KERNEL);
 573         if (head == NULL)
 574                 return -ENOBUFS;
 575         INIT_LIST_HEAD(&head->filters);
 576         tp->root = head;
 577         return 0;
 578 }
 579
 580 static void flow_destroy(struct tcf_proto *tp)
 581 {
 582         struct flow_head *head = tp->root;
 583         struct flow_filter *f, *next;
 584
 585         list_for_each_entry_safe(f, next, &head->filters, list) {
 586                 list_del(&f->list);
 587                 flow_destroy_filter(tp, f);
 588         }
 589         kfree(head);
 590 }
 591
 592 static unsigned long flow_get(struct tcf_proto *tp, u32 handle)
 593 {
 594         struct flow_head *head = tp->root;
 595         struct flow_filter *f;
 596
 597         list_for_each_entry(f, &head->filters, list)
 598                 if (f->handle == handle)
 599                         return (unsigned long)f;
 600         return 0;
 601 }
 602
 603 static void flow_put(struct tcf_proto *tp, unsigned long f)
 604 {
 605         return;
 606 }
 607
 608 static int flow_dump(struct tcf_proto *tp, unsigned long fh,
 609                      struct sk_buff *skb, struct tcmsg *t)
 610 {
 611         struct flow_filter *f = (struct flow_filter *)fh;
 612         struct nlattr *nest;
 613
 614         if (f == NULL)
 615                 return skb->len;
 616
 617         t->tcm_handle = f->handle;
 618
 619         nest = nla_nest_start(skb, TCA_OPTIONS);
 620         if (nest == NULL)
 621                 goto nla_put_failure;
 622
 623         NLA_PUT_U32(skb, TCA_FLOW_KEYS, f->keymask);
 624         NLA_PUT_U32(skb, TCA_FLOW_MODE, f->mode);
 625
 626         if (f->mask != ~0 || f->xor != 0) {
 627                 NLA_PUT_U32(skb, TCA_FLOW_MASK, f->mask);
 628                 NLA_PUT_U32(skb, TCA_FLOW_XOR, f->xor);
 629         }
 630         if (f->rshift)
 631                 NLA_PUT_U32(skb, TCA_FLOW_RSHIFT, f->rshift);
 632         if (f->addend)
 633                 NLA_PUT_U32(skb, TCA_FLOW_ADDEND, f->addend);
 634
 635         if (f->divisor)
 636                 NLA_PUT_U32(skb, TCA_FLOW_DIVISOR, f->divisor);
 637         if (f->baseclass)
 638                 NLA_PUT_U32(skb, TCA_FLOW_BASECLASS, f->baseclass);
 639
 640         if (f->perturb_period)
 641                 NLA_PUT_U32(skb, TCA_FLOW_PERTURB, f->perturb_period / HZ);
 642
 643         if (tcf_exts_dump(skb, &f->exts, &flow_ext_map) < 0)
 644                 goto nla_put_failure;
 645 #ifdef CONFIG_NET_EMATCH
 646         if (f->ematches.hdr.nmatches &&
 647             tcf_em_tree_dump(skb, &f->ematches, TCA_FLOW_EMATCHES) < 0)
 648                 goto nla_put_failure;
 649 #endif
 650         nla_nest_end(skb, nest);
 651
 652         if (tcf_exts_dump_stats(skb, &f->exts, &flow_ext_map) < 0)
 653                 goto nla_put_failure;
 654
 655         return skb->len;
 656
 657 nla_put_failure:
 658         nlmsg_trim(skb, nest);
 659         return -1;
 660 }
 661
 662 static void flow_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 663 {
 664         struct flow_head *head = tp->root;
 665         struct flow_filter *f;
 666
 667         list_for_each_entry(f, &head->filters, list) {
 668                 if (arg->count < arg->skip)
 669                         goto skip;
 670                 if (arg->fn(tp, (unsigned long)f, arg) < 0) {
 671                         arg->stop = 1;
 672                         break;
 673                 }
 674 skip:
 675                 arg->count++;
 676         }
 677 }
 678
 679 static struct tcf_proto_ops cls_flow_ops __read_mostly = {
 680         .kind           = "flow",
 681         .classify       = flow_classify,
 682         .init           = flow_init,
 683         .destroy        = flow_destroy,
 684         .change         = flow_change,
 685         .delete         = flow_delete,
 686         .get            = flow_get,
 687         .put            = flow_put,
 688         .dump           = flow_dump,
 689         .walk           = flow_walk,
 690         .owner          = THIS_MODULE,
 691 };
 692
 693 static int __init cls_flow_init(void)
 694 {
 695         return register_tcf_proto_ops(&cls_flow_ops);
 696 }
 697
 698 static void __exit cls_flow_exit(void)
 699 {
 700         unregister_tcf_proto_ops(&cls_flow_ops);
 701 }
 702
 703 module_init(cls_flow_init);
 704 module_exit(cls_flow_exit);
 705
 706 MODULE_LICENSE("GPL");
 707 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 708 MODULE_DESCRIPTION("TC flow classifier");