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 #include <linux/module.h> 25 #include <net/inet_sock.h> 26 27 #include <net/pkt_cls.h> 28 #include <net/ip.h> 29 #include <net/route.h> 30 #include <net/flow_dissector.h> 31 32 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 33 #include <net/netfilter/nf_conntrack.h> 34 #endif 35 36 struct flow_head { 37 struct list_head filters; 38 struct rcu_head rcu; 39 }; 40 41 struct flow_filter { 42 struct list_head list; 43 struct tcf_exts exts; 44 struct tcf_ematch_tree ematches; 45 struct tcf_proto *tp; 46 struct timer_list perturb_timer; 47 u32 perturb_period; 48 u32 handle; 49 50 u32 nkeys; 51 u32 keymask; 52 u32 mode; 53 u32 mask; 54 u32 xor; 55 u32 rshift; 56 u32 addend; 57 u32 divisor; 58 u32 baseclass; 59 u32 hashrnd; 60 union { 61 struct work_struct work; 62 struct rcu_head rcu; 63 }; 64 }; 65 66 static inline u32 addr_fold(void *addr) 67 { 68 unsigned long a = (unsigned long)addr; 69 70 return (a & 0xFFFFFFFF) ^ (BITS_PER_LONG > 32 ? a >> 32 : 0); 71 } 72 73 static u32 flow_get_src(const struct sk_buff *skb, const struct flow_keys *flow) 74 { 75 __be32 src = flow_get_u32_src(flow); 76 77 if (src) 78 return ntohl(src); 79 80 return addr_fold(skb->sk); 81 } 82 83 static u32 flow_get_dst(const struct sk_buff *skb, const struct flow_keys *flow) 84 { 85 __be32 dst = flow_get_u32_dst(flow); 86 87 if (dst) 88 return ntohl(dst); 89 90 return addr_fold(skb_dst(skb)) ^ (__force u16) tc_skb_protocol(skb); 91 } 92 93 static u32 flow_get_proto(const struct sk_buff *skb, 94 const struct flow_keys *flow) 95 { 96 return flow->basic.ip_proto; 97 } 98 99 static u32 flow_get_proto_src(const struct sk_buff *skb, 100 const struct flow_keys *flow) 101 { 102 if (flow->ports.ports) 103 return ntohs(flow->ports.src); 104 105 return addr_fold(skb->sk); 106 } 107 108 static u32 flow_get_proto_dst(const struct sk_buff *skb, 109 const struct flow_keys *flow) 110 { 111 if (flow->ports.ports) 112 return ntohs(flow->ports.dst); 113 114 return addr_fold(skb_dst(skb)) ^ (__force u16) tc_skb_protocol(skb); 115 } 116 117 static u32 flow_get_iif(const struct sk_buff *skb) 118 { 119 return skb->skb_iif; 120 } 121 122 static u32 flow_get_priority(const struct sk_buff *skb) 123 { 124 return skb->priority; 125 } 126 127 static u32 flow_get_mark(const struct sk_buff *skb) 128 { 129 return skb->mark; 130 } 131 132 static u32 flow_get_nfct(const struct sk_buff *skb) 133 { 134 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 135 return addr_fold(skb_nfct(skb)); 136 #else 137 return 0; 138 #endif 139 } 140 141 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 142 #define CTTUPLE(skb, member) \ 143 ({ \ 144 enum ip_conntrack_info ctinfo; \ 145 const struct nf_conn *ct = nf_ct_get(skb, &ctinfo); \ 146 if (ct == NULL) \ 147 goto fallback; \ 148 ct->tuplehash[CTINFO2DIR(ctinfo)].tuple.member; \ 149 }) 150 #else 151 #define CTTUPLE(skb, member) \ 152 ({ \ 153 goto fallback; \ 154 0; \ 155 }) 156 #endif 157 158 static u32 flow_get_nfct_src(const struct sk_buff *skb, 159 const struct flow_keys *flow) 160 { 161 switch (tc_skb_protocol(skb)) { 162 case htons(ETH_P_IP): 163 return ntohl(CTTUPLE(skb, src.u3.ip)); 164 case htons(ETH_P_IPV6): 165 return ntohl(CTTUPLE(skb, src.u3.ip6[3])); 166 } 167 fallback: 168 return flow_get_src(skb, flow); 169 } 170 171 static u32 flow_get_nfct_dst(const struct sk_buff *skb, 172 const struct flow_keys *flow) 173 { 174 switch (tc_skb_protocol(skb)) { 175 case htons(ETH_P_IP): 176 return ntohl(CTTUPLE(skb, dst.u3.ip)); 177 case htons(ETH_P_IPV6): 178 return ntohl(CTTUPLE(skb, dst.u3.ip6[3])); 179 } 180 fallback: 181 return flow_get_dst(skb, flow); 182 } 183 184 static u32 flow_get_nfct_proto_src(const struct sk_buff *skb, 185 const struct flow_keys *flow) 186 { 187 return ntohs(CTTUPLE(skb, src.u.all)); 188 fallback: 189 return flow_get_proto_src(skb, flow); 190 } 191 192 static u32 flow_get_nfct_proto_dst(const struct sk_buff *skb, 193 const struct flow_keys *flow) 194 { 195 return ntohs(CTTUPLE(skb, dst.u.all)); 196 fallback: 197 return flow_get_proto_dst(skb, flow); 198 } 199 200 static u32 flow_get_rtclassid(const struct sk_buff *skb) 201 { 202 #ifdef CONFIG_IP_ROUTE_CLASSID 203 if (skb_dst(skb)) 204 return skb_dst(skb)->tclassid; 205 #endif 206 return 0; 207 } 208 209 static u32 flow_get_skuid(const struct sk_buff *skb) 210 { 211 struct sock *sk = skb_to_full_sk(skb); 212 213 if (sk && sk->sk_socket && sk->sk_socket->file) { 214 kuid_t skuid = sk->sk_socket->file->f_cred->fsuid; 215 216 return from_kuid(&init_user_ns, skuid); 217 } 218 return 0; 219 } 220 221 static u32 flow_get_skgid(const struct sk_buff *skb) 222 { 223 struct sock *sk = skb_to_full_sk(skb); 224 225 if (sk && sk->sk_socket && sk->sk_socket->file) { 226 kgid_t skgid = sk->sk_socket->file->f_cred->fsgid; 227 228 return from_kgid(&init_user_ns, skgid); 229 } 230 return 0; 231 } 232 233 static u32 flow_get_vlan_tag(const struct sk_buff *skb) 234 { 235 u16 uninitialized_var(tag); 236 237 if (vlan_get_tag(skb, &tag) < 0) 238 return 0; 239 return tag & VLAN_VID_MASK; 240 } 241 242 static u32 flow_get_rxhash(struct sk_buff *skb) 243 { 244 return skb_get_hash(skb); 245 } 246 247 static u32 flow_key_get(struct sk_buff *skb, int key, struct flow_keys *flow) 248 { 249 switch (key) { 250 case FLOW_KEY_SRC: 251 return flow_get_src(skb, flow); 252 case FLOW_KEY_DST: 253 return flow_get_dst(skb, flow); 254 case FLOW_KEY_PROTO: 255 return flow_get_proto(skb, flow); 256 case FLOW_KEY_PROTO_SRC: 257 return flow_get_proto_src(skb, flow); 258 case FLOW_KEY_PROTO_DST: 259 return flow_get_proto_dst(skb, flow); 260 case FLOW_KEY_IIF: 261 return flow_get_iif(skb); 262 case FLOW_KEY_PRIORITY: 263 return flow_get_priority(skb); 264 case FLOW_KEY_MARK: 265 return flow_get_mark(skb); 266 case FLOW_KEY_NFCT: 267 return flow_get_nfct(skb); 268 case FLOW_KEY_NFCT_SRC: 269 return flow_get_nfct_src(skb, flow); 270 case FLOW_KEY_NFCT_DST: 271 return flow_get_nfct_dst(skb, flow); 272 case FLOW_KEY_NFCT_PROTO_SRC: 273 return flow_get_nfct_proto_src(skb, flow); 274 case FLOW_KEY_NFCT_PROTO_DST: 275 return flow_get_nfct_proto_dst(skb, flow); 276 case FLOW_KEY_RTCLASSID: 277 return flow_get_rtclassid(skb); 278 case FLOW_KEY_SKUID: 279 return flow_get_skuid(skb); 280 case FLOW_KEY_SKGID: 281 return flow_get_skgid(skb); 282 case FLOW_KEY_VLAN_TAG: 283 return flow_get_vlan_tag(skb); 284 case FLOW_KEY_RXHASH: 285 return flow_get_rxhash(skb); 286 default: 287 WARN_ON(1); 288 return 0; 289 } 290 } 291 292 #define FLOW_KEYS_NEEDED ((1 << FLOW_KEY_SRC) | \ 293 (1 << FLOW_KEY_DST) | \ 294 (1 << FLOW_KEY_PROTO) | \ 295 (1 << FLOW_KEY_PROTO_SRC) | \ 296 (1 << FLOW_KEY_PROTO_DST) | \ 297 (1 << FLOW_KEY_NFCT_SRC) | \ 298 (1 << FLOW_KEY_NFCT_DST) | \ 299 (1 << FLOW_KEY_NFCT_PROTO_SRC) | \ 300 (1 << FLOW_KEY_NFCT_PROTO_DST)) 301 302 static int flow_classify(struct sk_buff *skb, const struct tcf_proto *tp, 303 struct tcf_result *res) 304 { 305 struct flow_head *head = rcu_dereference_bh(tp->root); 306 struct flow_filter *f; 307 u32 keymask; 308 u32 classid; 309 unsigned int n, key; 310 int r; 311 312 list_for_each_entry_rcu(f, &head->filters, list) { 313 u32 keys[FLOW_KEY_MAX + 1]; 314 struct flow_keys flow_keys; 315 316 if (!tcf_em_tree_match(skb, &f->ematches, NULL)) 317 continue; 318 319 keymask = f->keymask; 320 if (keymask & FLOW_KEYS_NEEDED) 321 skb_flow_dissect_flow_keys(skb, &flow_keys, 0); 322 323 for (n = 0; n < f->nkeys; n++) { 324 key = ffs(keymask) - 1; 325 keymask &= ~(1 << key); 326 keys[n] = flow_key_get(skb, key, &flow_keys); 327 } 328 329 if (f->mode == FLOW_MODE_HASH) 330 classid = jhash2(keys, f->nkeys, f->hashrnd); 331 else { 332 classid = keys[0]; 333 classid = (classid & f->mask) ^ f->xor; 334 classid = (classid >> f->rshift) + f->addend; 335 } 336 337 if (f->divisor) 338 classid %= f->divisor; 339 340 res->class = 0; 341 res->classid = TC_H_MAKE(f->baseclass, f->baseclass + classid); 342 343 r = tcf_exts_exec(skb, &f->exts, res); 344 if (r < 0) 345 continue; 346 return r; 347 } 348 return -1; 349 } 350 351 static void flow_perturbation(struct timer_list *t) 352 { 353 struct flow_filter *f = from_timer(f, t, perturb_timer); 354 355 get_random_bytes(&f->hashrnd, 4); 356 if (f->perturb_period) 357 mod_timer(&f->perturb_timer, jiffies + f->perturb_period); 358 } 359 360 static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = { 361 [TCA_FLOW_KEYS] = { .type = NLA_U32 }, 362 [TCA_FLOW_MODE] = { .type = NLA_U32 }, 363 [TCA_FLOW_BASECLASS] = { .type = NLA_U32 }, 364 [TCA_FLOW_RSHIFT] = { .type = NLA_U32 }, 365 [TCA_FLOW_ADDEND] = { .type = NLA_U32 }, 366 [TCA_FLOW_MASK] = { .type = NLA_U32 }, 367 [TCA_FLOW_XOR] = { .type = NLA_U32 }, 368 [TCA_FLOW_DIVISOR] = { .type = NLA_U32 }, 369 [TCA_FLOW_ACT] = { .type = NLA_NESTED }, 370 [TCA_FLOW_POLICE] = { .type = NLA_NESTED }, 371 [TCA_FLOW_EMATCHES] = { .type = NLA_NESTED }, 372 [TCA_FLOW_PERTURB] = { .type = NLA_U32 }, 373 }; 374 375 static void __flow_destroy_filter(struct flow_filter *f) 376 { 377 del_timer_sync(&f->perturb_timer); 378 tcf_exts_destroy(&f->exts); 379 tcf_em_tree_destroy(&f->ematches); 380 tcf_exts_put_net(&f->exts); 381 kfree(f); 382 } 383 384 static void flow_destroy_filter_work(struct work_struct *work) 385 { 386 struct flow_filter *f = container_of(work, struct flow_filter, work); 387 388 rtnl_lock(); 389 __flow_destroy_filter(f); 390 rtnl_unlock(); 391 } 392 393 static void flow_destroy_filter(struct rcu_head *head) 394 { 395 struct flow_filter *f = container_of(head, struct flow_filter, rcu); 396 397 INIT_WORK(&f->work, flow_destroy_filter_work); 398 tcf_queue_work(&f->work); 399 } 400 401 static int flow_change(struct net *net, struct sk_buff *in_skb, 402 struct tcf_proto *tp, unsigned long base, 403 u32 handle, struct nlattr **tca, 404 void **arg, bool ovr, struct netlink_ext_ack *extack) 405 { 406 struct flow_head *head = rtnl_dereference(tp->root); 407 struct flow_filter *fold, *fnew; 408 struct nlattr *opt = tca[TCA_OPTIONS]; 409 struct nlattr *tb[TCA_FLOW_MAX + 1]; 410 unsigned int nkeys = 0; 411 unsigned int perturb_period = 0; 412 u32 baseclass = 0; 413 u32 keymask = 0; 414 u32 mode; 415 int err; 416 417 if (opt == NULL) 418 return -EINVAL; 419 420 err = nla_parse_nested(tb, TCA_FLOW_MAX, opt, flow_policy, NULL); 421 if (err < 0) 422 return err; 423 424 if (tb[TCA_FLOW_BASECLASS]) { 425 baseclass = nla_get_u32(tb[TCA_FLOW_BASECLASS]); 426 if (TC_H_MIN(baseclass) == 0) 427 return -EINVAL; 428 } 429 430 if (tb[TCA_FLOW_KEYS]) { 431 keymask = nla_get_u32(tb[TCA_FLOW_KEYS]); 432 433 nkeys = hweight32(keymask); 434 if (nkeys == 0) 435 return -EINVAL; 436 437 if (fls(keymask) - 1 > FLOW_KEY_MAX) 438 return -EOPNOTSUPP; 439 440 if ((keymask & (FLOW_KEY_SKUID|FLOW_KEY_SKGID)) && 441 sk_user_ns(NETLINK_CB(in_skb).sk) != &init_user_ns) 442 return -EOPNOTSUPP; 443 } 444 445 fnew = kzalloc(sizeof(*fnew), GFP_KERNEL); 446 if (!fnew) 447 return -ENOBUFS; 448 449 err = tcf_em_tree_validate(tp, tb[TCA_FLOW_EMATCHES], &fnew->ematches); 450 if (err < 0) 451 goto err1; 452 453 err = tcf_exts_init(&fnew->exts, TCA_FLOW_ACT, TCA_FLOW_POLICE); 454 if (err < 0) 455 goto err2; 456 457 err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &fnew->exts, ovr, 458 extack); 459 if (err < 0) 460 goto err2; 461 462 fold = *arg; 463 if (fold) { 464 err = -EINVAL; 465 if (fold->handle != handle && handle) 466 goto err2; 467 468 /* Copy fold into fnew */ 469 fnew->tp = fold->tp; 470 fnew->handle = fold->handle; 471 fnew->nkeys = fold->nkeys; 472 fnew->keymask = fold->keymask; 473 fnew->mode = fold->mode; 474 fnew->mask = fold->mask; 475 fnew->xor = fold->xor; 476 fnew->rshift = fold->rshift; 477 fnew->addend = fold->addend; 478 fnew->divisor = fold->divisor; 479 fnew->baseclass = fold->baseclass; 480 fnew->hashrnd = fold->hashrnd; 481 482 mode = fold->mode; 483 if (tb[TCA_FLOW_MODE]) 484 mode = nla_get_u32(tb[TCA_FLOW_MODE]); 485 if (mode != FLOW_MODE_HASH && nkeys > 1) 486 goto err2; 487 488 if (mode == FLOW_MODE_HASH) 489 perturb_period = fold->perturb_period; 490 if (tb[TCA_FLOW_PERTURB]) { 491 if (mode != FLOW_MODE_HASH) 492 goto err2; 493 perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ; 494 } 495 } else { 496 err = -EINVAL; 497 if (!handle) 498 goto err2; 499 if (!tb[TCA_FLOW_KEYS]) 500 goto err2; 501 502 mode = FLOW_MODE_MAP; 503 if (tb[TCA_FLOW_MODE]) 504 mode = nla_get_u32(tb[TCA_FLOW_MODE]); 505 if (mode != FLOW_MODE_HASH && nkeys > 1) 506 goto err2; 507 508 if (tb[TCA_FLOW_PERTURB]) { 509 if (mode != FLOW_MODE_HASH) 510 goto err2; 511 perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ; 512 } 513 514 if (TC_H_MAJ(baseclass) == 0) { 515 struct Qdisc *q = tcf_block_q(tp->chain->block); 516 517 baseclass = TC_H_MAKE(q->handle, baseclass); 518 } 519 if (TC_H_MIN(baseclass) == 0) 520 baseclass = TC_H_MAKE(baseclass, 1); 521 522 fnew->handle = handle; 523 fnew->mask = ~0U; 524 fnew->tp = tp; 525 get_random_bytes(&fnew->hashrnd, 4); 526 } 527 528 timer_setup(&fnew->perturb_timer, flow_perturbation, TIMER_DEFERRABLE); 529 530 tcf_block_netif_keep_dst(tp->chain->block); 531 532 if (tb[TCA_FLOW_KEYS]) { 533 fnew->keymask = keymask; 534 fnew->nkeys = nkeys; 535 } 536 537 fnew->mode = mode; 538 539 if (tb[TCA_FLOW_MASK]) 540 fnew->mask = nla_get_u32(tb[TCA_FLOW_MASK]); 541 if (tb[TCA_FLOW_XOR]) 542 fnew->xor = nla_get_u32(tb[TCA_FLOW_XOR]); 543 if (tb[TCA_FLOW_RSHIFT]) 544 fnew->rshift = nla_get_u32(tb[TCA_FLOW_RSHIFT]); 545 if (tb[TCA_FLOW_ADDEND]) 546 fnew->addend = nla_get_u32(tb[TCA_FLOW_ADDEND]); 547 548 if (tb[TCA_FLOW_DIVISOR]) 549 fnew->divisor = nla_get_u32(tb[TCA_FLOW_DIVISOR]); 550 if (baseclass) 551 fnew->baseclass = baseclass; 552 553 fnew->perturb_period = perturb_period; 554 if (perturb_period) 555 mod_timer(&fnew->perturb_timer, jiffies + perturb_period); 556 557 if (!*arg) 558 list_add_tail_rcu(&fnew->list, &head->filters); 559 else 560 list_replace_rcu(&fold->list, &fnew->list); 561 562 *arg = fnew; 563 564 if (fold) { 565 tcf_exts_get_net(&fold->exts); 566 call_rcu(&fold->rcu, flow_destroy_filter); 567 } 568 return 0; 569 570 err2: 571 tcf_exts_destroy(&fnew->exts); 572 tcf_em_tree_destroy(&fnew->ematches); 573 err1: 574 kfree(fnew); 575 return err; 576 } 577 578 static int flow_delete(struct tcf_proto *tp, void *arg, bool *last, 579 struct netlink_ext_ack *extack) 580 { 581 struct flow_head *head = rtnl_dereference(tp->root); 582 struct flow_filter *f = arg; 583 584 list_del_rcu(&f->list); 585 tcf_exts_get_net(&f->exts); 586 call_rcu(&f->rcu, flow_destroy_filter); 587 *last = list_empty(&head->filters); 588 return 0; 589 } 590 591 static int flow_init(struct tcf_proto *tp) 592 { 593 struct flow_head *head; 594 595 head = kzalloc(sizeof(*head), GFP_KERNEL); 596 if (head == NULL) 597 return -ENOBUFS; 598 INIT_LIST_HEAD(&head->filters); 599 rcu_assign_pointer(tp->root, head); 600 return 0; 601 } 602 603 static void flow_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack) 604 { 605 struct flow_head *head = rtnl_dereference(tp->root); 606 struct flow_filter *f, *next; 607 608 list_for_each_entry_safe(f, next, &head->filters, list) { 609 list_del_rcu(&f->list); 610 if (tcf_exts_get_net(&f->exts)) 611 call_rcu(&f->rcu, flow_destroy_filter); 612 else 613 __flow_destroy_filter(f); 614 } 615 kfree_rcu(head, rcu); 616 } 617 618 static void *flow_get(struct tcf_proto *tp, u32 handle) 619 { 620 struct flow_head *head = rtnl_dereference(tp->root); 621 struct flow_filter *f; 622 623 list_for_each_entry(f, &head->filters, list) 624 if (f->handle == handle) 625 return f; 626 return NULL; 627 } 628 629 static int flow_dump(struct net *net, struct tcf_proto *tp, void *fh, 630 struct sk_buff *skb, struct tcmsg *t) 631 { 632 struct flow_filter *f = fh; 633 struct nlattr *nest; 634 635 if (f == NULL) 636 return skb->len; 637 638 t->tcm_handle = f->handle; 639 640 nest = nla_nest_start(skb, TCA_OPTIONS); 641 if (nest == NULL) 642 goto nla_put_failure; 643 644 if (nla_put_u32(skb, TCA_FLOW_KEYS, f->keymask) || 645 nla_put_u32(skb, TCA_FLOW_MODE, f->mode)) 646 goto nla_put_failure; 647 648 if (f->mask != ~0 || f->xor != 0) { 649 if (nla_put_u32(skb, TCA_FLOW_MASK, f->mask) || 650 nla_put_u32(skb, TCA_FLOW_XOR, f->xor)) 651 goto nla_put_failure; 652 } 653 if (f->rshift && 654 nla_put_u32(skb, TCA_FLOW_RSHIFT, f->rshift)) 655 goto nla_put_failure; 656 if (f->addend && 657 nla_put_u32(skb, TCA_FLOW_ADDEND, f->addend)) 658 goto nla_put_failure; 659 660 if (f->divisor && 661 nla_put_u32(skb, TCA_FLOW_DIVISOR, f->divisor)) 662 goto nla_put_failure; 663 if (f->baseclass && 664 nla_put_u32(skb, TCA_FLOW_BASECLASS, f->baseclass)) 665 goto nla_put_failure; 666 667 if (f->perturb_period && 668 nla_put_u32(skb, TCA_FLOW_PERTURB, f->perturb_period / HZ)) 669 goto nla_put_failure; 670 671 if (tcf_exts_dump(skb, &f->exts) < 0) 672 goto nla_put_failure; 673 #ifdef CONFIG_NET_EMATCH 674 if (f->ematches.hdr.nmatches && 675 tcf_em_tree_dump(skb, &f->ematches, TCA_FLOW_EMATCHES) < 0) 676 goto nla_put_failure; 677 #endif 678 nla_nest_end(skb, nest); 679 680 if (tcf_exts_dump_stats(skb, &f->exts) < 0) 681 goto nla_put_failure; 682 683 return skb->len; 684 685 nla_put_failure: 686 nla_nest_cancel(skb, nest); 687 return -1; 688 } 689 690 static void flow_walk(struct tcf_proto *tp, struct tcf_walker *arg) 691 { 692 struct flow_head *head = rtnl_dereference(tp->root); 693 struct flow_filter *f; 694 695 list_for_each_entry(f, &head->filters, list) { 696 if (arg->count < arg->skip) 697 goto skip; 698 if (arg->fn(tp, f, arg) < 0) { 699 arg->stop = 1; 700 break; 701 } 702 skip: 703 arg->count++; 704 } 705 } 706 707 static struct tcf_proto_ops cls_flow_ops __read_mostly = { 708 .kind = "flow", 709 .classify = flow_classify, 710 .init = flow_init, 711 .destroy = flow_destroy, 712 .change = flow_change, 713 .delete = flow_delete, 714 .get = flow_get, 715 .dump = flow_dump, 716 .walk = flow_walk, 717 .owner = THIS_MODULE, 718 }; 719 720 static int __init cls_flow_init(void) 721 { 722 return register_tcf_proto_ops(&cls_flow_ops); 723 } 724 725 static void __exit cls_flow_exit(void) 726 { 727 unregister_tcf_proto_ops(&cls_flow_ops); 728 } 729 730 module_init(cls_flow_init); 731 module_exit(cls_flow_exit); 732 733 MODULE_LICENSE("GPL"); 734 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 735 MODULE_DESCRIPTION("TC flow classifier"); 736