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drm/r600: fix possible NULL pointer derefernce
[linux-2.6.git] / net / sched / cls_flow.c
blobf73542d2cdd0640d3f6ef7900cc44987e1be3544
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 }
606
607 static int flow_dump(struct tcf_proto *tp, unsigned long fh,
608 struct sk_buff *skb, struct tcmsg *t)
609 {
610 struct flow_filter *f = (struct flow_filter *)fh;
611 struct nlattr *nest;
612
613 if (f == NULL)
614 return skb->len;
615
616 t->tcm_handle = f->handle;
617
618 nest = nla_nest_start(skb, TCA_OPTIONS);
619 if (nest == NULL)
620 goto nla_put_failure;
621
622 NLA_PUT_U32(skb, TCA_FLOW_KEYS, f->keymask);
623 NLA_PUT_U32(skb, TCA_FLOW_MODE, f->mode);
624
625 if (f->mask != ~0 || f->xor != 0) {
626 NLA_PUT_U32(skb, TCA_FLOW_MASK, f->mask);
627 NLA_PUT_U32(skb, TCA_FLOW_XOR, f->xor);
628 }
629 if (f->rshift)
630 NLA_PUT_U32(skb, TCA_FLOW_RSHIFT, f->rshift);
631 if (f->addend)
632 NLA_PUT_U32(skb, TCA_FLOW_ADDEND, f->addend);
633
634 if (f->divisor)
635 NLA_PUT_U32(skb, TCA_FLOW_DIVISOR, f->divisor);
636 if (f->baseclass)
637 NLA_PUT_U32(skb, TCA_FLOW_BASECLASS, f->baseclass);
638
639 if (f->perturb_period)
640 NLA_PUT_U32(skb, TCA_FLOW_PERTURB, f->perturb_period / HZ);
641
642 if (tcf_exts_dump(skb, &f->exts, &flow_ext_map) < 0)
643 goto nla_put_failure;
644 #ifdef CONFIG_NET_EMATCH
645 if (f->ematches.hdr.nmatches &&
646 tcf_em_tree_dump(skb, &f->ematches, TCA_FLOW_EMATCHES) < 0)
647 goto nla_put_failure;
648 #endif
649 nla_nest_end(skb, nest);
650
651 if (tcf_exts_dump_stats(skb, &f->exts, &flow_ext_map) < 0)
652 goto nla_put_failure;
653
654 return skb->len;
655
656 nla_put_failure:
657 nlmsg_trim(skb, nest);
658 return -1;
659 }
660
661 static void flow_walk(struct tcf_proto *tp, struct tcf_walker *arg)
662 {
663 struct flow_head *head = tp->root;
664 struct flow_filter *f;
665
666 list_for_each_entry(f, &head->filters, list) {
667 if (arg->count < arg->skip)
668 goto skip;
669 if (arg->fn(tp, (unsigned long)f, arg) < 0) {
670 arg->stop = 1;
671 break;
672 }
673 skip:
674 arg->count++;
675 }
676 }
677
678 static struct tcf_proto_ops cls_flow_ops __read_mostly = {
679 .kind = "flow",
680 .classify = flow_classify,
681 .init = flow_init,
682 .destroy = flow_destroy,
683 .change = flow_change,
684 .delete = flow_delete,
685 .get = flow_get,
686 .put = flow_put,
687 .dump = flow_dump,
688 .walk = flow_walk,
689 .owner = THIS_MODULE,
690 };
691
692 static int __init cls_flow_init(void)
693 {
694 return register_tcf_proto_ops(&cls_flow_ops);
695 }
696
697 static void __exit cls_flow_exit(void)
698 {
699 unregister_tcf_proto_ops(&cls_flow_ops);
700 }
701
702 module_init(cls_flow_init);
703 module_exit(cls_flow_exit);
704
705 MODULE_LICENSE("GPL");
706 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
707 MODULE_DESCRIPTION("TC flow classifier");
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