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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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. | |
10297b99 | 40 | * |
1da177e4 LT |
41 | * ========================================================================== |
42 | * | |
43 | * How to write an ematch in 60 seconds | |
44 | * ------------------------------------ | |
10297b99 | 45 | * |
1da177e4 LT |
46 | * 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 | * { | |
4d24b52a | 74 | * tcf_em_unregister(&my_ops); |
1da177e4 LT |
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 | ||
1da177e4 | 84 | #include <linux/module.h> |
5a0e3ad6 | 85 | #include <linux/slab.h> |
1da177e4 LT |
86 | #include <linux/types.h> |
87 | #include <linux/kernel.h> | |
1da177e4 | 88 | #include <linux/errno.h> |
1da177e4 LT |
89 | #include <linux/rtnetlink.h> |
90 | #include <linux/skbuff.h> | |
91 | #include <net/pkt_cls.h> | |
1da177e4 LT |
92 | |
93 | static LIST_HEAD(ematch_ops); | |
94 | static DEFINE_RWLOCK(ematch_mod_lock); | |
95 | ||
cc7ec456 | 96 | static struct tcf_ematch_ops *tcf_em_lookup(u16 kind) |
1da177e4 LT |
97 | { |
98 | struct tcf_ematch_ops *e = NULL; | |
99 | ||
100 | read_lock(&ematch_mod_lock); | |
101 | list_for_each_entry(e, &ematch_ops, link) { | |
102 | if (kind == e->kind) { | |
103 | if (!try_module_get(e->owner)) | |
104 | e = NULL; | |
105 | read_unlock(&ematch_mod_lock); | |
106 | return e; | |
107 | } | |
108 | } | |
109 | read_unlock(&ematch_mod_lock); | |
110 | ||
111 | return NULL; | |
112 | } | |
113 | ||
114 | /** | |
115 | * tcf_em_register - register an extended match | |
10297b99 | 116 | * |
1da177e4 LT |
117 | * @ops: ematch operations lookup table |
118 | * | |
119 | * This function must be called by ematches to announce their presence. | |
120 | * The given @ops must have kind set to a unique identifier and the | |
121 | * callback match() must be implemented. All other callbacks are optional | |
122 | * and a fallback implementation is used instead. | |
123 | * | |
124 | * Returns -EEXISTS if an ematch of the same kind has already registered. | |
125 | */ | |
126 | int tcf_em_register(struct tcf_ematch_ops *ops) | |
127 | { | |
128 | int err = -EEXIST; | |
129 | struct tcf_ematch_ops *e; | |
130 | ||
131 | if (ops->match == NULL) | |
132 | return -EINVAL; | |
133 | ||
134 | write_lock(&ematch_mod_lock); | |
135 | list_for_each_entry(e, &ematch_ops, link) | |
136 | if (ops->kind == e->kind) | |
137 | goto errout; | |
138 | ||
139 | list_add_tail(&ops->link, &ematch_ops); | |
140 | err = 0; | |
141 | errout: | |
142 | write_unlock(&ematch_mod_lock); | |
143 | return err; | |
144 | } | |
62e3ba1b | 145 | EXPORT_SYMBOL(tcf_em_register); |
1da177e4 LT |
146 | |
147 | /** | |
148 | * tcf_em_unregister - unregster and extended match | |
149 | * | |
150 | * @ops: ematch operations lookup table | |
151 | * | |
152 | * This function must be called by ematches to announce their disappearance | |
153 | * for examples when the module gets unloaded. The @ops parameter must be | |
154 | * the same as the one used for registration. | |
155 | * | |
156 | * Returns -ENOENT if no matching ematch was found. | |
157 | */ | |
4d24b52a | 158 | void tcf_em_unregister(struct tcf_ematch_ops *ops) |
1da177e4 | 159 | { |
1da177e4 | 160 | write_lock(&ematch_mod_lock); |
4d24b52a | 161 | list_del(&ops->link); |
1da177e4 | 162 | write_unlock(&ematch_mod_lock); |
1da177e4 | 163 | } |
62e3ba1b | 164 | EXPORT_SYMBOL(tcf_em_unregister); |
1da177e4 | 165 | |
cc7ec456 ED |
166 | static inline struct tcf_ematch *tcf_em_get_match(struct tcf_ematch_tree *tree, |
167 | int index) | |
1da177e4 LT |
168 | { |
169 | return &tree->matches[index]; | |
170 | } | |
171 | ||
172 | ||
173 | static int tcf_em_validate(struct tcf_proto *tp, | |
174 | struct tcf_ematch_tree_hdr *tree_hdr, | |
add93b61 | 175 | struct tcf_ematch *em, struct nlattr *nla, int idx) |
1da177e4 LT |
176 | { |
177 | int err = -EINVAL; | |
add93b61 PM |
178 | struct tcf_ematch_hdr *em_hdr = nla_data(nla); |
179 | int data_len = nla_len(nla) - sizeof(*em_hdr); | |
1da177e4 | 180 | void *data = (void *) em_hdr + sizeof(*em_hdr); |
82a470f1 | 181 | struct net *net = dev_net(qdisc_dev(tp->q)); |
1da177e4 LT |
182 | |
183 | if (!TCF_EM_REL_VALID(em_hdr->flags)) | |
184 | goto errout; | |
185 | ||
186 | if (em_hdr->kind == TCF_EM_CONTAINER) { | |
187 | /* Special ematch called "container", carries an index | |
cc7ec456 ED |
188 | * referencing an external ematch sequence. |
189 | */ | |
1da177e4 LT |
190 | u32 ref; |
191 | ||
192 | if (data_len < sizeof(ref)) | |
193 | goto errout; | |
194 | ref = *(u32 *) data; | |
195 | ||
196 | if (ref >= tree_hdr->nmatches) | |
197 | goto errout; | |
198 | ||
199 | /* We do not allow backward jumps to avoid loops and jumps | |
cc7ec456 ED |
200 | * to our own position are of course illegal. |
201 | */ | |
1da177e4 LT |
202 | if (ref <= idx) |
203 | goto errout; | |
204 | ||
10297b99 | 205 | |
1da177e4 LT |
206 | em->data = ref; |
207 | } else { | |
208 | /* Note: This lookup will increase the module refcnt | |
209 | * of the ematch module referenced. In case of a failure, | |
210 | * a destroy function is called by the underlying layer | |
211 | * which automatically releases the reference again, therefore | |
212 | * the module MUST not be given back under any circumstances | |
213 | * here. Be aware, the destroy function assumes that the | |
cc7ec456 ED |
214 | * module is held if the ops field is non zero. |
215 | */ | |
1da177e4 LT |
216 | em->ops = tcf_em_lookup(em_hdr->kind); |
217 | ||
218 | if (em->ops == NULL) { | |
219 | err = -ENOENT; | |
95a5afca | 220 | #ifdef CONFIG_MODULES |
db3d99c0 PM |
221 | __rtnl_unlock(); |
222 | request_module("ematch-kind-%u", em_hdr->kind); | |
223 | rtnl_lock(); | |
224 | em->ops = tcf_em_lookup(em_hdr->kind); | |
225 | if (em->ops) { | |
226 | /* We dropped the RTNL mutex in order to | |
227 | * perform the module load. Tell the caller | |
cc7ec456 ED |
228 | * to replay the request. |
229 | */ | |
db3d99c0 PM |
230 | module_put(em->ops->owner); |
231 | err = -EAGAIN; | |
232 | } | |
233 | #endif | |
1da177e4 LT |
234 | goto errout; |
235 | } | |
236 | ||
237 | /* ematch module provides expected length of data, so we | |
cc7ec456 ED |
238 | * can do a basic sanity check. |
239 | */ | |
1da177e4 LT |
240 | if (em->ops->datalen && data_len < em->ops->datalen) |
241 | goto errout; | |
242 | ||
243 | if (em->ops->change) { | |
82a470f1 | 244 | err = em->ops->change(net, data, data_len, em); |
1da177e4 LT |
245 | if (err < 0) |
246 | goto errout; | |
247 | } else if (data_len > 0) { | |
248 | /* ematch module doesn't provide an own change | |
249 | * procedure and expects us to allocate and copy | |
250 | * the ematch data. | |
251 | * | |
252 | * TCF_EM_SIMPLE may be specified stating that the | |
253 | * data only consists of a u32 integer and the module | |
254 | * does not expected a memory reference but rather | |
cc7ec456 ED |
255 | * the value carried. |
256 | */ | |
1da177e4 LT |
257 | if (em_hdr->flags & TCF_EM_SIMPLE) { |
258 | if (data_len < sizeof(u32)) | |
259 | goto errout; | |
260 | em->data = *(u32 *) data; | |
261 | } else { | |
c7b1b249 | 262 | void *v = kmemdup(data, data_len, GFP_KERNEL); |
1da177e4 LT |
263 | if (v == NULL) { |
264 | err = -ENOBUFS; | |
265 | goto errout; | |
266 | } | |
1da177e4 LT |
267 | em->data = (unsigned long) v; |
268 | } | |
269 | } | |
270 | } | |
271 | ||
272 | em->matchid = em_hdr->matchid; | |
273 | em->flags = em_hdr->flags; | |
274 | em->datalen = data_len; | |
82a470f1 | 275 | em->net = net; |
1da177e4 LT |
276 | |
277 | err = 0; | |
278 | errout: | |
279 | return err; | |
280 | } | |
281 | ||
7a9c1bd4 PM |
282 | static const struct nla_policy em_policy[TCA_EMATCH_TREE_MAX + 1] = { |
283 | [TCA_EMATCH_TREE_HDR] = { .len = sizeof(struct tcf_ematch_tree_hdr) }, | |
284 | [TCA_EMATCH_TREE_LIST] = { .type = NLA_NESTED }, | |
285 | }; | |
286 | ||
1da177e4 LT |
287 | /** |
288 | * tcf_em_tree_validate - validate ematch config TLV and build ematch tree | |
289 | * | |
290 | * @tp: classifier kind handle | |
add93b61 | 291 | * @nla: ematch tree configuration TLV |
1da177e4 LT |
292 | * @tree: destination ematch tree variable to store the resulting |
293 | * ematch tree. | |
294 | * | |
add93b61 | 295 | * This function validates the given configuration TLV @nla and builds an |
1da177e4 LT |
296 | * ematch tree in @tree. The resulting tree must later be copied into |
297 | * the private classifier data using tcf_em_tree_change(). You MUST NOT | |
298 | * provide the ematch tree variable of the private classifier data directly, | |
299 | * the changes would not be locked properly. | |
300 | * | |
301 | * Returns a negative error code if the configuration TLV contains errors. | |
302 | */ | |
add93b61 | 303 | int tcf_em_tree_validate(struct tcf_proto *tp, struct nlattr *nla, |
1da177e4 LT |
304 | struct tcf_ematch_tree *tree) |
305 | { | |
cee63723 | 306 | int idx, list_len, matches_len, err; |
add93b61 PM |
307 | struct nlattr *tb[TCA_EMATCH_TREE_MAX + 1]; |
308 | struct nlattr *rt_match, *rt_hdr, *rt_list; | |
1da177e4 LT |
309 | struct tcf_ematch_tree_hdr *tree_hdr; |
310 | struct tcf_ematch *em; | |
311 | ||
268bcca1 SH |
312 | memset(tree, 0, sizeof(*tree)); |
313 | if (!nla) | |
b541ca2c | 314 | return 0; |
b541ca2c | 315 | |
7a9c1bd4 | 316 | err = nla_parse_nested(tb, TCA_EMATCH_TREE_MAX, nla, em_policy); |
cee63723 | 317 | if (err < 0) |
1da177e4 LT |
318 | goto errout; |
319 | ||
cee63723 | 320 | err = -EINVAL; |
add93b61 PM |
321 | rt_hdr = tb[TCA_EMATCH_TREE_HDR]; |
322 | rt_list = tb[TCA_EMATCH_TREE_LIST]; | |
1da177e4 LT |
323 | |
324 | if (rt_hdr == NULL || rt_list == NULL) | |
325 | goto errout; | |
326 | ||
add93b61 | 327 | tree_hdr = nla_data(rt_hdr); |
1da177e4 LT |
328 | memcpy(&tree->hdr, tree_hdr, sizeof(*tree_hdr)); |
329 | ||
add93b61 PM |
330 | rt_match = nla_data(rt_list); |
331 | list_len = nla_len(rt_list); | |
1da177e4 LT |
332 | matches_len = tree_hdr->nmatches * sizeof(*em); |
333 | ||
0da974f4 | 334 | tree->matches = kzalloc(matches_len, GFP_KERNEL); |
1da177e4 LT |
335 | if (tree->matches == NULL) |
336 | goto errout; | |
1da177e4 | 337 | |
add93b61 | 338 | /* We do not use nla_parse_nested here because the maximum |
1da177e4 LT |
339 | * number of attributes is unknown. This saves us the allocation |
340 | * for a tb buffer which would serve no purpose at all. | |
10297b99 | 341 | * |
1da177e4 LT |
342 | * The array of rt attributes is parsed in the order as they are |
343 | * provided, their type must be incremental from 1 to n. Even | |
344 | * if it does not serve any real purpose, a failure of sticking | |
cc7ec456 ED |
345 | * to this policy will result in parsing failure. |
346 | */ | |
add93b61 | 347 | for (idx = 0; nla_ok(rt_match, list_len); idx++) { |
1da177e4 LT |
348 | err = -EINVAL; |
349 | ||
add93b61 | 350 | if (rt_match->nla_type != (idx + 1)) |
1da177e4 LT |
351 | goto errout_abort; |
352 | ||
353 | if (idx >= tree_hdr->nmatches) | |
354 | goto errout_abort; | |
355 | ||
add93b61 | 356 | if (nla_len(rt_match) < sizeof(struct tcf_ematch_hdr)) |
1da177e4 LT |
357 | goto errout_abort; |
358 | ||
359 | em = tcf_em_get_match(tree, idx); | |
360 | ||
361 | err = tcf_em_validate(tp, tree_hdr, em, rt_match, idx); | |
362 | if (err < 0) | |
363 | goto errout_abort; | |
364 | ||
add93b61 | 365 | rt_match = nla_next(rt_match, &list_len); |
1da177e4 LT |
366 | } |
367 | ||
368 | /* Check if the number of matches provided by userspace actually | |
369 | * complies with the array of matches. The number was used for | |
370 | * the validation of references and a mismatch could lead to | |
cc7ec456 ED |
371 | * undefined references during the matching process. |
372 | */ | |
1da177e4 LT |
373 | if (idx != tree_hdr->nmatches) { |
374 | err = -EINVAL; | |
375 | goto errout_abort; | |
376 | } | |
377 | ||
378 | err = 0; | |
379 | errout: | |
380 | return err; | |
381 | ||
382 | errout_abort: | |
82a470f1 | 383 | tcf_em_tree_destroy(tree); |
1da177e4 LT |
384 | return err; |
385 | } | |
62e3ba1b | 386 | EXPORT_SYMBOL(tcf_em_tree_validate); |
1da177e4 LT |
387 | |
388 | /** | |
389 | * tcf_em_tree_destroy - destroy an ematch tree | |
390 | * | |
391 | * @tp: classifier kind handle | |
392 | * @tree: ematch tree to be deleted | |
393 | * | |
394 | * This functions destroys an ematch tree previously created by | |
395 | * tcf_em_tree_validate()/tcf_em_tree_change(). You must ensure that | |
396 | * the ematch tree is not in use before calling this function. | |
397 | */ | |
82a470f1 | 398 | void tcf_em_tree_destroy(struct tcf_ematch_tree *tree) |
1da177e4 LT |
399 | { |
400 | int i; | |
401 | ||
402 | if (tree->matches == NULL) | |
403 | return; | |
404 | ||
405 | for (i = 0; i < tree->hdr.nmatches; i++) { | |
406 | struct tcf_ematch *em = tcf_em_get_match(tree, i); | |
407 | ||
408 | if (em->ops) { | |
409 | if (em->ops->destroy) | |
82a470f1 | 410 | em->ops->destroy(em); |
954415e3 | 411 | else if (!tcf_em_is_simple(em)) |
30ddb159 | 412 | kfree((void *) em->data); |
1da177e4 LT |
413 | module_put(em->ops->owner); |
414 | } | |
415 | } | |
10297b99 | 416 | |
1da177e4 LT |
417 | tree->hdr.nmatches = 0; |
418 | kfree(tree->matches); | |
954415e3 | 419 | tree->matches = NULL; |
1da177e4 | 420 | } |
62e3ba1b | 421 | EXPORT_SYMBOL(tcf_em_tree_destroy); |
1da177e4 LT |
422 | |
423 | /** | |
424 | * tcf_em_tree_dump - dump ematch tree into a rtnl message | |
425 | * | |
426 | * @skb: skb holding the rtnl message | |
427 | * @t: ematch tree to be dumped | |
428 | * @tlv: TLV type to be used to encapsulate the tree | |
429 | * | |
430 | * This function dumps a ematch tree into a rtnl message. It is valid to | |
431 | * call this function while the ematch tree is in use. | |
432 | * | |
433 | * Returns -1 if the skb tailroom is insufficient. | |
434 | */ | |
435 | int tcf_em_tree_dump(struct sk_buff *skb, struct tcf_ematch_tree *tree, int tlv) | |
436 | { | |
437 | int i; | |
27a884dc | 438 | u8 *tail; |
4b3550ef | 439 | struct nlattr *top_start; |
add93b61 | 440 | struct nlattr *list_start; |
1da177e4 | 441 | |
4b3550ef PM |
442 | top_start = nla_nest_start(skb, tlv); |
443 | if (top_start == NULL) | |
444 | goto nla_put_failure; | |
445 | ||
1b34ec43 DM |
446 | if (nla_put(skb, TCA_EMATCH_TREE_HDR, sizeof(tree->hdr), &tree->hdr)) |
447 | goto nla_put_failure; | |
1da177e4 | 448 | |
4b3550ef PM |
449 | list_start = nla_nest_start(skb, TCA_EMATCH_TREE_LIST); |
450 | if (list_start == NULL) | |
451 | goto nla_put_failure; | |
1da177e4 | 452 | |
27a884dc | 453 | tail = skb_tail_pointer(skb); |
1da177e4 | 454 | for (i = 0; i < tree->hdr.nmatches; i++) { |
add93b61 | 455 | struct nlattr *match_start = (struct nlattr *)tail; |
1da177e4 LT |
456 | 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 | ||
1b34ec43 DM |
463 | if (nla_put(skb, i + 1, sizeof(em_hdr), &em_hdr)) |
464 | goto nla_put_failure; | |
1da177e4 LT |
465 | |
466 | if (em->ops && em->ops->dump) { | |
467 | if (em->ops->dump(skb, em) < 0) | |
add93b61 | 468 | goto nla_put_failure; |
1da177e4 LT |
469 | } else if (tcf_em_is_container(em) || tcf_em_is_simple(em)) { |
470 | u32 u = em->data; | |
add93b61 | 471 | nla_put_nohdr(skb, sizeof(u), &u); |
1da177e4 | 472 | } else if (em->datalen > 0) |
add93b61 | 473 | nla_put_nohdr(skb, em->datalen, (void *) em->data); |
1da177e4 | 474 | |
27a884dc | 475 | tail = skb_tail_pointer(skb); |
add93b61 | 476 | match_start->nla_len = tail - (u8 *)match_start; |
1da177e4 LT |
477 | } |
478 | ||
4b3550ef PM |
479 | nla_nest_end(skb, list_start); |
480 | nla_nest_end(skb, top_start); | |
1da177e4 LT |
481 | |
482 | return 0; | |
483 | ||
add93b61 | 484 | nla_put_failure: |
1da177e4 LT |
485 | return -1; |
486 | } | |
62e3ba1b | 487 | EXPORT_SYMBOL(tcf_em_tree_dump); |
1da177e4 LT |
488 | |
489 | static inline int tcf_em_match(struct sk_buff *skb, struct tcf_ematch *em, | |
490 | struct tcf_pkt_info *info) | |
491 | { | |
492 | int r = em->ops->match(skb, em, info); | |
cc7ec456 | 493 | |
1da177e4 LT |
494 | return tcf_em_is_inverted(em) ? !r : r; |
495 | } | |
496 | ||
497 | /* Do not use this function directly, use tcf_em_tree_match instead */ | |
498 | int __tcf_em_tree_match(struct sk_buff *skb, struct tcf_ematch_tree *tree, | |
499 | struct tcf_pkt_info *info) | |
500 | { | |
501 | int stackp = 0, match_idx = 0, res = 0; | |
502 | struct tcf_ematch *cur_match; | |
503 | int stack[CONFIG_NET_EMATCH_STACK]; | |
504 | ||
505 | proceed: | |
506 | while (match_idx < tree->hdr.nmatches) { | |
507 | cur_match = tcf_em_get_match(tree, match_idx); | |
508 | ||
509 | if (tcf_em_is_container(cur_match)) { | |
510 | if (unlikely(stackp >= CONFIG_NET_EMATCH_STACK)) | |
511 | goto stack_overflow; | |
512 | ||
513 | stack[stackp++] = match_idx; | |
514 | match_idx = cur_match->data; | |
515 | goto proceed; | |
516 | } | |
517 | ||
518 | res = tcf_em_match(skb, cur_match, info); | |
519 | ||
520 | if (tcf_em_early_end(cur_match, res)) | |
521 | break; | |
522 | ||
523 | match_idx++; | |
524 | } | |
525 | ||
526 | pop_stack: | |
527 | if (stackp > 0) { | |
528 | match_idx = stack[--stackp]; | |
529 | cur_match = tcf_em_get_match(tree, match_idx); | |
530 | ||
34a419d4 IG |
531 | if (tcf_em_is_inverted(cur_match)) |
532 | res = !res; | |
533 | ||
17c9c823 | 534 | if (tcf_em_early_end(cur_match, res)) { |
1da177e4 | 535 | goto pop_stack; |
17c9c823 | 536 | } else { |
1da177e4 LT |
537 | match_idx++; |
538 | goto proceed; | |
539 | } | |
540 | } | |
541 | ||
542 | return res; | |
543 | ||
544 | stack_overflow: | |
e87cc472 | 545 | net_warn_ratelimited("tc ematch: local stack overflow, increase NET_EMATCH_STACK\n"); |
1da177e4 LT |
546 | return -1; |
547 | } | |
1da177e4 | 548 | EXPORT_SYMBOL(__tcf_em_tree_match); |