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cls_fw.c
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1 /*
2  * net/sched/cls_fw.c Classifier mapping ipchains' fwmark to traffic class.
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: Alexey Kuznetsov, <[email protected]>
10  *
11  * Changes:
12  * Karlis Peisenieks <[email protected]> : 990415 : fw_walk off by one
13  * Karlis Peisenieks <[email protected]> : 990415 : fw_delete killed all the filter (and kernel).
14  * Alex <[email protected]> : 2004xxyy: Added Action extension
15  *
16  * JHS: We should remove the CONFIG_NET_CLS_IND from here
17  * eventually when the meta match extension is made available
18  *
19  */
20 
21 #include <linux/module.h>
22 #include <linux/slab.h>
23 #include <linux/types.h>
24 #include <linux/kernel.h>
25 #include <linux/string.h>
26 #include <linux/errno.h>
27 #include <linux/skbuff.h>
28 #include <net/netlink.h>
29 #include <net/act_api.h>
30 #include <net/pkt_cls.h>
31 
32 #define HTSIZE (PAGE_SIZE/sizeof(struct fw_filter *))
33 
34 struct fw_head {
35  struct fw_filter *ht[HTSIZE];
36  u32 mask;
37 };
38 
39 struct fw_filter {
40  struct fw_filter *next;
41  u32 id;
42  struct tcf_result res;
43 #ifdef CONFIG_NET_CLS_IND
44  char indev[IFNAMSIZ];
45 #endif /* CONFIG_NET_CLS_IND */
46  struct tcf_exts exts;
47 };
48 
49 static const struct tcf_ext_map fw_ext_map = {
50  .action = TCA_FW_ACT,
51  .police = TCA_FW_POLICE
52 };
53 
54 static inline int fw_hash(u32 handle)
55 {
56  if (HTSIZE == 4096)
57  return ((handle >> 24) & 0xFFF) ^
58  ((handle >> 12) & 0xFFF) ^
59  (handle & 0xFFF);
60  else if (HTSIZE == 2048)
61  return ((handle >> 22) & 0x7FF) ^
62  ((handle >> 11) & 0x7FF) ^
63  (handle & 0x7FF);
64  else if (HTSIZE == 1024)
65  return ((handle >> 20) & 0x3FF) ^
66  ((handle >> 10) & 0x3FF) ^
67  (handle & 0x3FF);
68  else if (HTSIZE == 512)
69  return (handle >> 27) ^
70  ((handle >> 18) & 0x1FF) ^
71  ((handle >> 9) & 0x1FF) ^
72  (handle & 0x1FF);
73  else if (HTSIZE == 256) {
74  u8 *t = (u8 *) &handle;
75  return t[0] ^ t[1] ^ t[2] ^ t[3];
76  } else
77  return handle & (HTSIZE - 1);
78 }
79 
80 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
81  struct tcf_result *res)
82 {
83  struct fw_head *head = (struct fw_head *)tp->root;
84  struct fw_filter *f;
85  int r;
86  u32 id = skb->mark;
87 
88  if (head != NULL) {
89  id &= head->mask;
90  for (f = head->ht[fw_hash(id)]; f; f = f->next) {
91  if (f->id == id) {
92  *res = f->res;
93 #ifdef CONFIG_NET_CLS_IND
94  if (!tcf_match_indev(skb, f->indev))
95  continue;
96 #endif /* CONFIG_NET_CLS_IND */
97  r = tcf_exts_exec(skb, &f->exts, res);
98  if (r < 0)
99  continue;
100 
101  return r;
102  }
103  }
104  } else {
105  /* old method */
106  if (id && (TC_H_MAJ(id) == 0 ||
107  !(TC_H_MAJ(id ^ tp->q->handle)))) {
108  res->classid = id;
109  res->class = 0;
110  return 0;
111  }
112  }
113 
114  return -1;
115 }
116 
117 static unsigned long fw_get(struct tcf_proto *tp, u32 handle)
118 {
119  struct fw_head *head = (struct fw_head *)tp->root;
120  struct fw_filter *f;
121 
122  if (head == NULL)
123  return 0;
124 
125  for (f = head->ht[fw_hash(handle)]; f; f = f->next) {
126  if (f->id == handle)
127  return (unsigned long)f;
128  }
129  return 0;
130 }
131 
132 static void fw_put(struct tcf_proto *tp, unsigned long f)
133 {
134 }
135 
136 static int fw_init(struct tcf_proto *tp)
137 {
138  return 0;
139 }
140 
141 static void fw_delete_filter(struct tcf_proto *tp, struct fw_filter *f)
142 {
143  tcf_unbind_filter(tp, &f->res);
144  tcf_exts_destroy(tp, &f->exts);
145  kfree(f);
146 }
147 
148 static void fw_destroy(struct tcf_proto *tp)
149 {
150  struct fw_head *head = tp->root;
151  struct fw_filter *f;
152  int h;
153 
154  if (head == NULL)
155  return;
156 
157  for (h = 0; h < HTSIZE; h++) {
158  while ((f = head->ht[h]) != NULL) {
159  head->ht[h] = f->next;
160  fw_delete_filter(tp, f);
161  }
162  }
163  kfree(head);
164 }
165 
166 static int fw_delete(struct tcf_proto *tp, unsigned long arg)
167 {
168  struct fw_head *head = (struct fw_head *)tp->root;
169  struct fw_filter *f = (struct fw_filter *)arg;
170  struct fw_filter **fp;
171 
172  if (head == NULL || f == NULL)
173  goto out;
174 
175  for (fp = &head->ht[fw_hash(f->id)]; *fp; fp = &(*fp)->next) {
176  if (*fp == f) {
177  tcf_tree_lock(tp);
178  *fp = f->next;
179  tcf_tree_unlock(tp);
180  fw_delete_filter(tp, f);
181  return 0;
182  }
183  }
184 out:
185  return -EINVAL;
186 }
187 
188 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
189  [TCA_FW_CLASSID] = { .type = NLA_U32 },
190  [TCA_FW_INDEV] = { .type = NLA_STRING, .len = IFNAMSIZ },
191  [TCA_FW_MASK] = { .type = NLA_U32 },
192 };
193 
194 static int
195 fw_change_attrs(struct tcf_proto *tp, struct fw_filter *f,
196  struct nlattr **tb, struct nlattr **tca, unsigned long base)
197 {
198  struct fw_head *head = (struct fw_head *)tp->root;
199  struct tcf_exts e;
200  u32 mask;
201  int err;
202 
203  err = tcf_exts_validate(tp, tb, tca[TCA_RATE], &e, &fw_ext_map);
204  if (err < 0)
205  return err;
206 
207  err = -EINVAL;
208  if (tb[TCA_FW_CLASSID]) {
209  f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
210  tcf_bind_filter(tp, &f->res, base);
211  }
212 
213 #ifdef CONFIG_NET_CLS_IND
214  if (tb[TCA_FW_INDEV]) {
215  err = tcf_change_indev(tp, f->indev, tb[TCA_FW_INDEV]);
216  if (err < 0)
217  goto errout;
218  }
219 #endif /* CONFIG_NET_CLS_IND */
220 
221  if (tb[TCA_FW_MASK]) {
222  mask = nla_get_u32(tb[TCA_FW_MASK]);
223  if (mask != head->mask)
224  goto errout;
225  } else if (head->mask != 0xFFFFFFFF)
226  goto errout;
227 
228  tcf_exts_change(tp, &f->exts, &e);
229 
230  return 0;
231 errout:
232  tcf_exts_destroy(tp, &e);
233  return err;
234 }
235 
236 static int fw_change(struct sk_buff *in_skb,
237  struct tcf_proto *tp, unsigned long base,
238  u32 handle,
239  struct nlattr **tca,
240  unsigned long *arg)
241 {
242  struct fw_head *head = (struct fw_head *)tp->root;
243  struct fw_filter *f = (struct fw_filter *) *arg;
244  struct nlattr *opt = tca[TCA_OPTIONS];
245  struct nlattr *tb[TCA_FW_MAX + 1];
246  int err;
247 
248  if (!opt)
249  return handle ? -EINVAL : 0;
250 
251  err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy);
252  if (err < 0)
253  return err;
254 
255  if (f != NULL) {
256  if (f->id != handle && handle)
257  return -EINVAL;
258  return fw_change_attrs(tp, f, tb, tca, base);
259  }
260 
261  if (!handle)
262  return -EINVAL;
263 
264  if (head == NULL) {
265  u32 mask = 0xFFFFFFFF;
266  if (tb[TCA_FW_MASK])
267  mask = nla_get_u32(tb[TCA_FW_MASK]);
268 
269  head = kzalloc(sizeof(struct fw_head), GFP_KERNEL);
270  if (head == NULL)
271  return -ENOBUFS;
272  head->mask = mask;
273 
274  tcf_tree_lock(tp);
275  tp->root = head;
276  tcf_tree_unlock(tp);
277  }
278 
279  f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
280  if (f == NULL)
281  return -ENOBUFS;
282 
283  f->id = handle;
284 
285  err = fw_change_attrs(tp, f, tb, tca, base);
286  if (err < 0)
287  goto errout;
288 
289  f->next = head->ht[fw_hash(handle)];
290  tcf_tree_lock(tp);
291  head->ht[fw_hash(handle)] = f;
292  tcf_tree_unlock(tp);
293 
294  *arg = (unsigned long)f;
295  return 0;
296 
297 errout:
298  kfree(f);
299  return err;
300 }
301 
302 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
303 {
304  struct fw_head *head = (struct fw_head *)tp->root;
305  int h;
306 
307  if (head == NULL)
308  arg->stop = 1;
309 
310  if (arg->stop)
311  return;
312 
313  for (h = 0; h < HTSIZE; h++) {
314  struct fw_filter *f;
315 
316  for (f = head->ht[h]; f; f = f->next) {
317  if (arg->count < arg->skip) {
318  arg->count++;
319  continue;
320  }
321  if (arg->fn(tp, (unsigned long)f, arg) < 0) {
322  arg->stop = 1;
323  return;
324  }
325  arg->count++;
326  }
327  }
328 }
329 
330 static int fw_dump(struct tcf_proto *tp, unsigned long fh,
331  struct sk_buff *skb, struct tcmsg *t)
332 {
333  struct fw_head *head = (struct fw_head *)tp->root;
334  struct fw_filter *f = (struct fw_filter *)fh;
335  unsigned char *b = skb_tail_pointer(skb);
336  struct nlattr *nest;
337 
338  if (f == NULL)
339  return skb->len;
340 
341  t->tcm_handle = f->id;
342 
343  if (!f->res.classid && !tcf_exts_is_available(&f->exts))
344  return skb->len;
345 
346  nest = nla_nest_start(skb, TCA_OPTIONS);
347  if (nest == NULL)
348  goto nla_put_failure;
349 
350  if (f->res.classid &&
351  nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
352  goto nla_put_failure;
353 #ifdef CONFIG_NET_CLS_IND
354  if (strlen(f->indev) &&
355  nla_put_string(skb, TCA_FW_INDEV, f->indev))
356  goto nla_put_failure;
357 #endif /* CONFIG_NET_CLS_IND */
358  if (head->mask != 0xFFFFFFFF &&
359  nla_put_u32(skb, TCA_FW_MASK, head->mask))
360  goto nla_put_failure;
361 
362  if (tcf_exts_dump(skb, &f->exts, &fw_ext_map) < 0)
363  goto nla_put_failure;
364 
365  nla_nest_end(skb, nest);
366 
367  if (tcf_exts_dump_stats(skb, &f->exts, &fw_ext_map) < 0)
368  goto nla_put_failure;
369 
370  return skb->len;
371 
372 nla_put_failure:
373  nlmsg_trim(skb, b);
374  return -1;
375 }
376 
377 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
378  .kind = "fw",
379  .classify = fw_classify,
380  .init = fw_init,
381  .destroy = fw_destroy,
382  .get = fw_get,
383  .put = fw_put,
384  .change = fw_change,
385  .delete = fw_delete,
386  .walk = fw_walk,
387  .dump = fw_dump,
388  .owner = THIS_MODULE,
389 };
390 
391 static int __init init_fw(void)
392 {
393  return register_tcf_proto_ops(&cls_fw_ops);
394 }
395 
396 static void __exit exit_fw(void)
397 {
398  unregister_tcf_proto_ops(&cls_fw_ops);
399 }
400 
401 module_init(init_fw)
402 module_exit(exit_fw)
403 MODULE_LICENSE("GPL");
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