blob: e82519e548d70c747f602bc179ca487f120ef5af [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * net/sched/ematch.c Extended Match API
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: Thomas Graf <tgraf@suug.ch>
10 *
11 * ==========================================================================
12 *
13 * An extended match (ematch) is a small classification tool not worth
14 * writing a full classifier for. Ematches can be interconnected to form
15 * a logic expression and get attached to classifiers to extend their
16 * functionatlity.
17 *
18 * The userspace part transforms the logic expressions into an array
19 * consisting of multiple sequences of interconnected ematches separated
20 * by markers. Precedence is implemented by a special ematch kind
21 * referencing a sequence beyond the marker of the current sequence
22 * causing the current position in the sequence to be pushed onto a stack
23 * to allow the current position to be overwritten by the position referenced
24 * in the special ematch. Matching continues in the new sequence until a
25 * marker is reached causing the position to be restored from the stack.
26 *
27 * Example:
28 * A AND (B1 OR B2) AND C AND D
29 *
30 * ------->-PUSH-------
31 * -->-- / -->-- \ -->--
32 * / \ / / \ \ / \
33 * +-------+-------+-------+-------+-------+--------+
34 * | A AND | B AND | C AND | D END | B1 OR | B2 END |
35 * +-------+-------+-------+-------+-------+--------+
36 * \ /
37 * --------<-POP---------
38 *
39 * where B is a virtual ematch referencing to sequence starting with B1.
YOSHIFUJI Hideaki10297b92007-02-09 23:25:16 +090040 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 * ==========================================================================
42 *
43 * How to write an ematch in 60 seconds
44 * ------------------------------------
YOSHIFUJI Hideaki10297b92007-02-09 23:25:16 +090045 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 * 1) Provide a matcher function:
47 * static int my_match(struct sk_buff *skb, struct tcf_ematch *m,
48 * struct tcf_pkt_info *info)
49 * {
50 * struct mydata *d = (struct mydata *) m->data;
51 *
52 * if (...matching goes here...)
53 * return 1;
54 * else
55 * return 0;
56 * }
57 *
58 * 2) Fill out a struct tcf_ematch_ops:
59 * static struct tcf_ematch_ops my_ops = {
60 * .kind = unique id,
61 * .datalen = sizeof(struct mydata),
62 * .match = my_match,
63 * .owner = THIS_MODULE,
64 * };
65 *
66 * 3) Register/Unregister your ematch:
67 * static int __init init_my_ematch(void)
68 * {
69 * return tcf_em_register(&my_ops);
70 * }
71 *
72 * static void __exit exit_my_ematch(void)
73 * {
74 * return tcf_em_unregister(&my_ops);
75 * }
76 *
77 * module_init(init_my_ematch);
78 * module_exit(exit_my_ematch);
79 *
80 * 4) By now you should have two more seconds left, barely enough to
81 * open up a beer to watch the compilation going.
82 */
83
Linus Torvalds1da177e2005-04-16 15:20:36 -070084#include <linux/module.h>
85#include <linux/types.h>
86#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070087#include <linux/errno.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070088#include <linux/rtnetlink.h>
89#include <linux/skbuff.h>
90#include <net/pkt_cls.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
92static LIST_HEAD(ematch_ops);
93static DEFINE_RWLOCK(ematch_mod_lock);
94
95static inline struct tcf_ematch_ops * tcf_em_lookup(u16 kind)
96{
97 struct tcf_ematch_ops *e = NULL;
98
99 read_lock(&ematch_mod_lock);
100 list_for_each_entry(e, &ematch_ops, link) {
101 if (kind == e->kind) {
102 if (!try_module_get(e->owner))
103 e = NULL;
104 read_unlock(&ematch_mod_lock);
105 return e;
106 }
107 }
108 read_unlock(&ematch_mod_lock);
109
110 return NULL;
111}
112
113/**
114 * tcf_em_register - register an extended match
YOSHIFUJI Hideaki10297b92007-02-09 23:25:16 +0900115 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 * @ops: ematch operations lookup table
117 *
118 * This function must be called by ematches to announce their presence.
119 * The given @ops must have kind set to a unique identifier and the
120 * callback match() must be implemented. All other callbacks are optional
121 * and a fallback implementation is used instead.
122 *
123 * Returns -EEXISTS if an ematch of the same kind has already registered.
124 */
125int tcf_em_register(struct tcf_ematch_ops *ops)
126{
127 int err = -EEXIST;
128 struct tcf_ematch_ops *e;
129
130 if (ops->match == NULL)
131 return -EINVAL;
132
133 write_lock(&ematch_mod_lock);
134 list_for_each_entry(e, &ematch_ops, link)
135 if (ops->kind == e->kind)
136 goto errout;
137
138 list_add_tail(&ops->link, &ematch_ops);
139 err = 0;
140errout:
141 write_unlock(&ematch_mod_lock);
142 return err;
143}
Patrick McHardy62e3ba12008-01-22 22:10:23 -0800144EXPORT_SYMBOL(tcf_em_register);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
146/**
147 * tcf_em_unregister - unregster and extended match
148 *
149 * @ops: ematch operations lookup table
150 *
151 * This function must be called by ematches to announce their disappearance
152 * for examples when the module gets unloaded. The @ops parameter must be
153 * the same as the one used for registration.
154 *
155 * Returns -ENOENT if no matching ematch was found.
156 */
157int tcf_em_unregister(struct tcf_ematch_ops *ops)
158{
159 int err = 0;
160 struct tcf_ematch_ops *e;
161
162 write_lock(&ematch_mod_lock);
163 list_for_each_entry(e, &ematch_ops, link) {
164 if (e == ops) {
165 list_del(&e->link);
166 goto out;
167 }
168 }
169
170 err = -ENOENT;
171out:
172 write_unlock(&ematch_mod_lock);
173 return err;
174}
Patrick McHardy62e3ba12008-01-22 22:10:23 -0800175EXPORT_SYMBOL(tcf_em_unregister);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176
177static inline struct tcf_ematch * tcf_em_get_match(struct tcf_ematch_tree *tree,
178 int index)
179{
180 return &tree->matches[index];
181}
182
183
184static int tcf_em_validate(struct tcf_proto *tp,
185 struct tcf_ematch_tree_hdr *tree_hdr,
Patrick McHardyadd93b62008-01-22 22:11:33 -0800186 struct tcf_ematch *em, struct nlattr *nla, int idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187{
188 int err = -EINVAL;
Patrick McHardyadd93b62008-01-22 22:11:33 -0800189 struct tcf_ematch_hdr *em_hdr = nla_data(nla);
190 int data_len = nla_len(nla) - sizeof(*em_hdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 void *data = (void *) em_hdr + sizeof(*em_hdr);
192
193 if (!TCF_EM_REL_VALID(em_hdr->flags))
194 goto errout;
195
196 if (em_hdr->kind == TCF_EM_CONTAINER) {
197 /* Special ematch called "container", carries an index
198 * referencing an external ematch sequence. */
199 u32 ref;
200
201 if (data_len < sizeof(ref))
202 goto errout;
203 ref = *(u32 *) data;
204
205 if (ref >= tree_hdr->nmatches)
206 goto errout;
207
208 /* We do not allow backward jumps to avoid loops and jumps
209 * to our own position are of course illegal. */
210 if (ref <= idx)
211 goto errout;
212
YOSHIFUJI Hideaki10297b92007-02-09 23:25:16 +0900213
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 em->data = ref;
215 } else {
216 /* Note: This lookup will increase the module refcnt
217 * of the ematch module referenced. In case of a failure,
218 * a destroy function is called by the underlying layer
219 * which automatically releases the reference again, therefore
220 * the module MUST not be given back under any circumstances
221 * here. Be aware, the destroy function assumes that the
222 * module is held if the ops field is non zero. */
223 em->ops = tcf_em_lookup(em_hdr->kind);
224
225 if (em->ops == NULL) {
226 err = -ENOENT;
Johannes Berg95a5afc2008-10-16 15:24:51 -0700227#ifdef CONFIG_MODULES
Patrick McHardydb3d99c2007-07-11 19:46:26 -0700228 __rtnl_unlock();
229 request_module("ematch-kind-%u", em_hdr->kind);
230 rtnl_lock();
231 em->ops = tcf_em_lookup(em_hdr->kind);
232 if (em->ops) {
233 /* We dropped the RTNL mutex in order to
234 * perform the module load. Tell the caller
235 * to replay the request. */
236 module_put(em->ops->owner);
237 err = -EAGAIN;
238 }
239#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 goto errout;
241 }
242
243 /* ematch module provides expected length of data, so we
244 * can do a basic sanity check. */
245 if (em->ops->datalen && data_len < em->ops->datalen)
246 goto errout;
247
248 if (em->ops->change) {
249 err = em->ops->change(tp, data, data_len, em);
250 if (err < 0)
251 goto errout;
252 } else if (data_len > 0) {
253 /* ematch module doesn't provide an own change
254 * procedure and expects us to allocate and copy
255 * the ematch data.
256 *
257 * TCF_EM_SIMPLE may be specified stating that the
258 * data only consists of a u32 integer and the module
259 * does not expected a memory reference but rather
260 * the value carried. */
261 if (em_hdr->flags & TCF_EM_SIMPLE) {
262 if (data_len < sizeof(u32))
263 goto errout;
264 em->data = *(u32 *) data;
265 } else {
Arnaldo Carvalho de Meloc7b1b242006-11-21 01:19:40 -0200266 void *v = kmemdup(data, data_len, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 if (v == NULL) {
268 err = -ENOBUFS;
269 goto errout;
270 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 em->data = (unsigned long) v;
272 }
273 }
274 }
275
276 em->matchid = em_hdr->matchid;
277 em->flags = em_hdr->flags;
278 em->datalen = data_len;
279
280 err = 0;
281errout:
282 return err;
283}
284
Patrick McHardy7a9c1bd2008-01-23 20:36:45 -0800285static const struct nla_policy em_policy[TCA_EMATCH_TREE_MAX + 1] = {
286 [TCA_EMATCH_TREE_HDR] = { .len = sizeof(struct tcf_ematch_tree_hdr) },
287 [TCA_EMATCH_TREE_LIST] = { .type = NLA_NESTED },
288};
289
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290/**
291 * tcf_em_tree_validate - validate ematch config TLV and build ematch tree
292 *
293 * @tp: classifier kind handle
Patrick McHardyadd93b62008-01-22 22:11:33 -0800294 * @nla: ematch tree configuration TLV
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 * @tree: destination ematch tree variable to store the resulting
296 * ematch tree.
297 *
Patrick McHardyadd93b62008-01-22 22:11:33 -0800298 * This function validates the given configuration TLV @nla and builds an
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 * ematch tree in @tree. The resulting tree must later be copied into
300 * the private classifier data using tcf_em_tree_change(). You MUST NOT
301 * provide the ematch tree variable of the private classifier data directly,
302 * the changes would not be locked properly.
303 *
304 * Returns a negative error code if the configuration TLV contains errors.
305 */
Patrick McHardyadd93b62008-01-22 22:11:33 -0800306int tcf_em_tree_validate(struct tcf_proto *tp, struct nlattr *nla,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 struct tcf_ematch_tree *tree)
308{
Patrick McHardycee63722008-01-23 20:33:32 -0800309 int idx, list_len, matches_len, err;
Patrick McHardyadd93b62008-01-22 22:11:33 -0800310 struct nlattr *tb[TCA_EMATCH_TREE_MAX + 1];
311 struct nlattr *rt_match, *rt_hdr, *rt_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 struct tcf_ematch_tree_hdr *tree_hdr;
313 struct tcf_ematch *em;
314
Stephen Hemminger268bcca2008-02-09 03:47:19 -0800315 memset(tree, 0, sizeof(*tree));
316 if (!nla)
Thomas Grafb541ca22005-11-08 09:39:17 -0800317 return 0;
Thomas Grafb541ca22005-11-08 09:39:17 -0800318
Patrick McHardy7a9c1bd2008-01-23 20:36:45 -0800319 err = nla_parse_nested(tb, TCA_EMATCH_TREE_MAX, nla, em_policy);
Patrick McHardycee63722008-01-23 20:33:32 -0800320 if (err < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 goto errout;
322
Patrick McHardycee63722008-01-23 20:33:32 -0800323 err = -EINVAL;
Patrick McHardyadd93b62008-01-22 22:11:33 -0800324 rt_hdr = tb[TCA_EMATCH_TREE_HDR];
325 rt_list = tb[TCA_EMATCH_TREE_LIST];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326
327 if (rt_hdr == NULL || rt_list == NULL)
328 goto errout;
329
Patrick McHardyadd93b62008-01-22 22:11:33 -0800330 tree_hdr = nla_data(rt_hdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 memcpy(&tree->hdr, tree_hdr, sizeof(*tree_hdr));
332
Patrick McHardyadd93b62008-01-22 22:11:33 -0800333 rt_match = nla_data(rt_list);
334 list_len = nla_len(rt_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 matches_len = tree_hdr->nmatches * sizeof(*em);
336
Panagiotis Issaris0da974f2006-07-21 14:51:30 -0700337 tree->matches = kzalloc(matches_len, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 if (tree->matches == NULL)
339 goto errout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340
Patrick McHardyadd93b62008-01-22 22:11:33 -0800341 /* We do not use nla_parse_nested here because the maximum
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 * number of attributes is unknown. This saves us the allocation
343 * for a tb buffer which would serve no purpose at all.
YOSHIFUJI Hideaki10297b92007-02-09 23:25:16 +0900344 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 * The array of rt attributes is parsed in the order as they are
346 * provided, their type must be incremental from 1 to n. Even
347 * if it does not serve any real purpose, a failure of sticking
348 * to this policy will result in parsing failure. */
Patrick McHardyadd93b62008-01-22 22:11:33 -0800349 for (idx = 0; nla_ok(rt_match, list_len); idx++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 err = -EINVAL;
351
Patrick McHardyadd93b62008-01-22 22:11:33 -0800352 if (rt_match->nla_type != (idx + 1))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 goto errout_abort;
354
355 if (idx >= tree_hdr->nmatches)
356 goto errout_abort;
357
Patrick McHardyadd93b62008-01-22 22:11:33 -0800358 if (nla_len(rt_match) < sizeof(struct tcf_ematch_hdr))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 goto errout_abort;
360
361 em = tcf_em_get_match(tree, idx);
362
363 err = tcf_em_validate(tp, tree_hdr, em, rt_match, idx);
364 if (err < 0)
365 goto errout_abort;
366
Patrick McHardyadd93b62008-01-22 22:11:33 -0800367 rt_match = nla_next(rt_match, &list_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 }
369
370 /* Check if the number of matches provided by userspace actually
371 * complies with the array of matches. The number was used for
372 * the validation of references and a mismatch could lead to
373 * undefined references during the matching process. */
374 if (idx != tree_hdr->nmatches) {
375 err = -EINVAL;
376 goto errout_abort;
377 }
378
379 err = 0;
380errout:
381 return err;
382
383errout_abort:
384 tcf_em_tree_destroy(tp, tree);
385 return err;
386}
Patrick McHardy62e3ba12008-01-22 22:10:23 -0800387EXPORT_SYMBOL(tcf_em_tree_validate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388
389/**
390 * tcf_em_tree_destroy - destroy an ematch tree
391 *
392 * @tp: classifier kind handle
393 * @tree: ematch tree to be deleted
394 *
395 * This functions destroys an ematch tree previously created by
396 * tcf_em_tree_validate()/tcf_em_tree_change(). You must ensure that
397 * the ematch tree is not in use before calling this function.
398 */
399void tcf_em_tree_destroy(struct tcf_proto *tp, struct tcf_ematch_tree *tree)
400{
401 int i;
402
403 if (tree->matches == NULL)
404 return;
405
406 for (i = 0; i < tree->hdr.nmatches; i++) {
407 struct tcf_ematch *em = tcf_em_get_match(tree, i);
408
409 if (em->ops) {
410 if (em->ops->destroy)
411 em->ops->destroy(tp, em);
Stephen Hemminger954415e2008-02-09 23:26:53 -0800412 else if (!tcf_em_is_simple(em))
David S. Miller30ddb152008-02-10 03:48:15 -0800413 kfree((void *) em->data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 module_put(em->ops->owner);
415 }
416 }
YOSHIFUJI Hideaki10297b92007-02-09 23:25:16 +0900417
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 tree->hdr.nmatches = 0;
419 kfree(tree->matches);
Stephen Hemminger954415e2008-02-09 23:26:53 -0800420 tree->matches = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421}
Patrick McHardy62e3ba12008-01-22 22:10:23 -0800422EXPORT_SYMBOL(tcf_em_tree_destroy);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423
424/**
425 * tcf_em_tree_dump - dump ematch tree into a rtnl message
426 *
427 * @skb: skb holding the rtnl message
428 * @t: ematch tree to be dumped
429 * @tlv: TLV type to be used to encapsulate the tree
430 *
431 * This function dumps a ematch tree into a rtnl message. It is valid to
432 * call this function while the ematch tree is in use.
433 *
434 * Returns -1 if the skb tailroom is insufficient.
435 */
436int tcf_em_tree_dump(struct sk_buff *skb, struct tcf_ematch_tree *tree, int tlv)
437{
438 int i;
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700439 u8 *tail;
Patrick McHardy4b3550ef2008-01-23 20:34:11 -0800440 struct nlattr *top_start;
Patrick McHardyadd93b62008-01-22 22:11:33 -0800441 struct nlattr *list_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442
Patrick McHardy4b3550ef2008-01-23 20:34:11 -0800443 top_start = nla_nest_start(skb, tlv);
444 if (top_start == NULL)
445 goto nla_put_failure;
446
Patrick McHardyadd93b62008-01-22 22:11:33 -0800447 NLA_PUT(skb, TCA_EMATCH_TREE_HDR, sizeof(tree->hdr), &tree->hdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448
Patrick McHardy4b3550ef2008-01-23 20:34:11 -0800449 list_start = nla_nest_start(skb, TCA_EMATCH_TREE_LIST);
450 if (list_start == NULL)
451 goto nla_put_failure;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700453 tail = skb_tail_pointer(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 for (i = 0; i < tree->hdr.nmatches; i++) {
Patrick McHardyadd93b62008-01-22 22:11:33 -0800455 struct nlattr *match_start = (struct nlattr *)tail;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 struct tcf_ematch *em = tcf_em_get_match(tree, i);
457 struct tcf_ematch_hdr em_hdr = {
458 .kind = em->ops ? em->ops->kind : TCF_EM_CONTAINER,
459 .matchid = em->matchid,
460 .flags = em->flags
461 };
462
Patrick McHardyadd93b62008-01-22 22:11:33 -0800463 NLA_PUT(skb, i+1, sizeof(em_hdr), &em_hdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464
465 if (em->ops && em->ops->dump) {
466 if (em->ops->dump(skb, em) < 0)
Patrick McHardyadd93b62008-01-22 22:11:33 -0800467 goto nla_put_failure;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 } else if (tcf_em_is_container(em) || tcf_em_is_simple(em)) {
469 u32 u = em->data;
Patrick McHardyadd93b62008-01-22 22:11:33 -0800470 nla_put_nohdr(skb, sizeof(u), &u);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 } else if (em->datalen > 0)
Patrick McHardyadd93b62008-01-22 22:11:33 -0800472 nla_put_nohdr(skb, em->datalen, (void *) em->data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700474 tail = skb_tail_pointer(skb);
Patrick McHardyadd93b62008-01-22 22:11:33 -0800475 match_start->nla_len = tail - (u8 *)match_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 }
477
Patrick McHardy4b3550ef2008-01-23 20:34:11 -0800478 nla_nest_end(skb, list_start);
479 nla_nest_end(skb, top_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480
481 return 0;
482
Patrick McHardyadd93b62008-01-22 22:11:33 -0800483nla_put_failure:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 return -1;
485}
Patrick McHardy62e3ba12008-01-22 22:10:23 -0800486EXPORT_SYMBOL(tcf_em_tree_dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487
488static inline int tcf_em_match(struct sk_buff *skb, struct tcf_ematch *em,
489 struct tcf_pkt_info *info)
490{
491 int r = em->ops->match(skb, em, info);
492 return tcf_em_is_inverted(em) ? !r : r;
493}
494
495/* Do not use this function directly, use tcf_em_tree_match instead */
496int __tcf_em_tree_match(struct sk_buff *skb, struct tcf_ematch_tree *tree,
497 struct tcf_pkt_info *info)
498{
499 int stackp = 0, match_idx = 0, res = 0;
500 struct tcf_ematch *cur_match;
501 int stack[CONFIG_NET_EMATCH_STACK];
502
503proceed:
504 while (match_idx < tree->hdr.nmatches) {
505 cur_match = tcf_em_get_match(tree, match_idx);
506
507 if (tcf_em_is_container(cur_match)) {
508 if (unlikely(stackp >= CONFIG_NET_EMATCH_STACK))
509 goto stack_overflow;
510
511 stack[stackp++] = match_idx;
512 match_idx = cur_match->data;
513 goto proceed;
514 }
515
516 res = tcf_em_match(skb, cur_match, info);
517
518 if (tcf_em_early_end(cur_match, res))
519 break;
520
521 match_idx++;
522 }
523
524pop_stack:
525 if (stackp > 0) {
526 match_idx = stack[--stackp];
527 cur_match = tcf_em_get_match(tree, match_idx);
528
529 if (tcf_em_early_end(cur_match, res))
530 goto pop_stack;
531 else {
532 match_idx++;
533 goto proceed;
534 }
535 }
536
537 return res;
538
539stack_overflow:
540 if (net_ratelimit())
541 printk("Local stack overflow, increase NET_EMATCH_STACK\n");
542 return -1;
543}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544EXPORT_SYMBOL(__tcf_em_tree_match);