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14c0b97d TG |
1 | /* |
2 | * net/core/fib_rules.c Generic Routing Rules | |
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 as | |
6 | * published by the Free Software Foundation, version 2. | |
7 | * | |
8 | * Authors: Thomas Graf <tgraf@suug.ch> | |
9 | */ | |
10 | ||
14c0b97d TG |
11 | #include <linux/types.h> |
12 | #include <linux/kernel.h> | |
13 | #include <linux/list.h> | |
14 | #include <net/fib_rules.h> | |
15 | ||
16 | static LIST_HEAD(rules_ops); | |
17 | static DEFINE_SPINLOCK(rules_mod_lock); | |
18 | ||
19 | static void notify_rule_change(int event, struct fib_rule *rule, | |
c17084d2 TG |
20 | struct fib_rules_ops *ops, struct nlmsghdr *nlh, |
21 | u32 pid); | |
14c0b97d TG |
22 | |
23 | static struct fib_rules_ops *lookup_rules_ops(int family) | |
24 | { | |
25 | struct fib_rules_ops *ops; | |
26 | ||
27 | rcu_read_lock(); | |
28 | list_for_each_entry_rcu(ops, &rules_ops, list) { | |
29 | if (ops->family == family) { | |
30 | if (!try_module_get(ops->owner)) | |
31 | ops = NULL; | |
32 | rcu_read_unlock(); | |
33 | return ops; | |
34 | } | |
35 | } | |
36 | rcu_read_unlock(); | |
37 | ||
38 | return NULL; | |
39 | } | |
40 | ||
41 | static void rules_ops_put(struct fib_rules_ops *ops) | |
42 | { | |
43 | if (ops) | |
44 | module_put(ops->owner); | |
45 | } | |
46 | ||
47 | int fib_rules_register(struct fib_rules_ops *ops) | |
48 | { | |
49 | int err = -EEXIST; | |
50 | struct fib_rules_ops *o; | |
51 | ||
52 | if (ops->rule_size < sizeof(struct fib_rule)) | |
53 | return -EINVAL; | |
54 | ||
55 | if (ops->match == NULL || ops->configure == NULL || | |
56 | ops->compare == NULL || ops->fill == NULL || | |
57 | ops->action == NULL) | |
58 | return -EINVAL; | |
59 | ||
60 | spin_lock(&rules_mod_lock); | |
61 | list_for_each_entry(o, &rules_ops, list) | |
62 | if (ops->family == o->family) | |
63 | goto errout; | |
64 | ||
65 | list_add_tail_rcu(&ops->list, &rules_ops); | |
66 | err = 0; | |
67 | errout: | |
68 | spin_unlock(&rules_mod_lock); | |
69 | ||
70 | return err; | |
71 | } | |
72 | ||
73 | EXPORT_SYMBOL_GPL(fib_rules_register); | |
74 | ||
75 | static void cleanup_ops(struct fib_rules_ops *ops) | |
76 | { | |
77 | struct fib_rule *rule, *tmp; | |
78 | ||
79 | list_for_each_entry_safe(rule, tmp, ops->rules_list, list) { | |
80 | list_del_rcu(&rule->list); | |
81 | fib_rule_put(rule); | |
82 | } | |
83 | } | |
84 | ||
85 | int fib_rules_unregister(struct fib_rules_ops *ops) | |
86 | { | |
87 | int err = 0; | |
88 | struct fib_rules_ops *o; | |
89 | ||
90 | spin_lock(&rules_mod_lock); | |
91 | list_for_each_entry(o, &rules_ops, list) { | |
92 | if (o == ops) { | |
93 | list_del_rcu(&o->list); | |
94 | cleanup_ops(ops); | |
95 | goto out; | |
96 | } | |
97 | } | |
98 | ||
99 | err = -ENOENT; | |
100 | out: | |
101 | spin_unlock(&rules_mod_lock); | |
102 | ||
103 | synchronize_rcu(); | |
104 | ||
105 | return err; | |
106 | } | |
107 | ||
108 | EXPORT_SYMBOL_GPL(fib_rules_unregister); | |
109 | ||
110 | int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl, | |
111 | int flags, struct fib_lookup_arg *arg) | |
112 | { | |
113 | struct fib_rule *rule; | |
114 | int err; | |
115 | ||
116 | rcu_read_lock(); | |
117 | ||
118 | list_for_each_entry_rcu(rule, ops->rules_list, list) { | |
119 | if (rule->ifindex && (rule->ifindex != fl->iif)) | |
120 | continue; | |
121 | ||
b8964ed9 TG |
122 | if ((rule->mark ^ fl->mark) & rule->mark_mask) |
123 | continue; | |
124 | ||
14c0b97d TG |
125 | if (!ops->match(rule, fl, flags)) |
126 | continue; | |
127 | ||
128 | err = ops->action(rule, fl, flags, arg); | |
129 | if (err != -EAGAIN) { | |
130 | fib_rule_get(rule); | |
131 | arg->rule = rule; | |
132 | goto out; | |
133 | } | |
134 | } | |
135 | ||
136 | err = -ENETUNREACH; | |
137 | out: | |
138 | rcu_read_unlock(); | |
139 | ||
140 | return err; | |
141 | } | |
142 | ||
143 | EXPORT_SYMBOL_GPL(fib_rules_lookup); | |
144 | ||
145 | int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) | |
146 | { | |
147 | struct fib_rule_hdr *frh = nlmsg_data(nlh); | |
148 | struct fib_rules_ops *ops = NULL; | |
149 | struct fib_rule *rule, *r, *last = NULL; | |
150 | struct nlattr *tb[FRA_MAX+1]; | |
151 | int err = -EINVAL; | |
152 | ||
153 | if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) | |
154 | goto errout; | |
155 | ||
156 | ops = lookup_rules_ops(frh->family); | |
157 | if (ops == NULL) { | |
158 | err = EAFNOSUPPORT; | |
159 | goto errout; | |
160 | } | |
161 | ||
162 | err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy); | |
163 | if (err < 0) | |
164 | goto errout; | |
165 | ||
14c0b97d TG |
166 | rule = kzalloc(ops->rule_size, GFP_KERNEL); |
167 | if (rule == NULL) { | |
168 | err = -ENOMEM; | |
169 | goto errout; | |
170 | } | |
171 | ||
172 | if (tb[FRA_PRIORITY]) | |
173 | rule->pref = nla_get_u32(tb[FRA_PRIORITY]); | |
174 | ||
175 | if (tb[FRA_IFNAME]) { | |
176 | struct net_device *dev; | |
177 | ||
178 | rule->ifindex = -1; | |
5176f91e | 179 | nla_strlcpy(rule->ifname, tb[FRA_IFNAME], IFNAMSIZ); |
14c0b97d TG |
180 | dev = __dev_get_by_name(rule->ifname); |
181 | if (dev) | |
182 | rule->ifindex = dev->ifindex; | |
183 | } | |
184 | ||
b8964ed9 TG |
185 | if (tb[FRA_FWMARK]) { |
186 | rule->mark = nla_get_u32(tb[FRA_FWMARK]); | |
187 | if (rule->mark) | |
188 | /* compatibility: if the mark value is non-zero all bits | |
189 | * are compared unless a mask is explicitly specified. | |
190 | */ | |
191 | rule->mark_mask = 0xFFFFFFFF; | |
192 | } | |
193 | ||
194 | if (tb[FRA_FWMASK]) | |
195 | rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]); | |
196 | ||
14c0b97d TG |
197 | rule->action = frh->action; |
198 | rule->flags = frh->flags; | |
9e762a4a | 199 | rule->table = frh_get_table(frh, tb); |
14c0b97d TG |
200 | |
201 | if (!rule->pref && ops->default_pref) | |
202 | rule->pref = ops->default_pref(); | |
203 | ||
204 | err = ops->configure(rule, skb, nlh, frh, tb); | |
205 | if (err < 0) | |
206 | goto errout_free; | |
207 | ||
208 | list_for_each_entry(r, ops->rules_list, list) { | |
209 | if (r->pref > rule->pref) | |
210 | break; | |
211 | last = r; | |
212 | } | |
213 | ||
214 | fib_rule_get(rule); | |
215 | ||
216 | if (last) | |
217 | list_add_rcu(&rule->list, &last->list); | |
218 | else | |
219 | list_add_rcu(&rule->list, ops->rules_list); | |
220 | ||
c17084d2 | 221 | notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).pid); |
14c0b97d TG |
222 | rules_ops_put(ops); |
223 | return 0; | |
224 | ||
225 | errout_free: | |
226 | kfree(rule); | |
227 | errout: | |
228 | rules_ops_put(ops); | |
229 | return err; | |
230 | } | |
231 | ||
232 | int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) | |
233 | { | |
234 | struct fib_rule_hdr *frh = nlmsg_data(nlh); | |
235 | struct fib_rules_ops *ops = NULL; | |
236 | struct fib_rule *rule; | |
237 | struct nlattr *tb[FRA_MAX+1]; | |
238 | int err = -EINVAL; | |
239 | ||
240 | if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) | |
241 | goto errout; | |
242 | ||
243 | ops = lookup_rules_ops(frh->family); | |
244 | if (ops == NULL) { | |
245 | err = EAFNOSUPPORT; | |
246 | goto errout; | |
247 | } | |
248 | ||
249 | err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy); | |
250 | if (err < 0) | |
251 | goto errout; | |
252 | ||
253 | list_for_each_entry(rule, ops->rules_list, list) { | |
254 | if (frh->action && (frh->action != rule->action)) | |
255 | continue; | |
256 | ||
9e762a4a | 257 | if (frh->table && (frh_get_table(frh, tb) != rule->table)) |
14c0b97d TG |
258 | continue; |
259 | ||
260 | if (tb[FRA_PRIORITY] && | |
261 | (rule->pref != nla_get_u32(tb[FRA_PRIORITY]))) | |
262 | continue; | |
263 | ||
264 | if (tb[FRA_IFNAME] && | |
265 | nla_strcmp(tb[FRA_IFNAME], rule->ifname)) | |
266 | continue; | |
267 | ||
b8964ed9 TG |
268 | if (tb[FRA_FWMARK] && |
269 | (rule->mark != nla_get_u32(tb[FRA_FWMARK]))) | |
270 | continue; | |
271 | ||
272 | if (tb[FRA_FWMASK] && | |
273 | (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK]))) | |
274 | continue; | |
275 | ||
14c0b97d TG |
276 | if (!ops->compare(rule, frh, tb)) |
277 | continue; | |
278 | ||
279 | if (rule->flags & FIB_RULE_PERMANENT) { | |
280 | err = -EPERM; | |
281 | goto errout; | |
282 | } | |
283 | ||
284 | list_del_rcu(&rule->list); | |
285 | synchronize_rcu(); | |
c17084d2 TG |
286 | notify_rule_change(RTM_DELRULE, rule, ops, nlh, |
287 | NETLINK_CB(skb).pid); | |
14c0b97d TG |
288 | fib_rule_put(rule); |
289 | rules_ops_put(ops); | |
290 | return 0; | |
291 | } | |
292 | ||
293 | err = -ENOENT; | |
294 | errout: | |
295 | rules_ops_put(ops); | |
296 | return err; | |
297 | } | |
298 | ||
299 | static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule, | |
300 | u32 pid, u32 seq, int type, int flags, | |
301 | struct fib_rules_ops *ops) | |
302 | { | |
303 | struct nlmsghdr *nlh; | |
304 | struct fib_rule_hdr *frh; | |
305 | ||
306 | nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags); | |
307 | if (nlh == NULL) | |
308 | return -1; | |
309 | ||
310 | frh = nlmsg_data(nlh); | |
311 | frh->table = rule->table; | |
9e762a4a | 312 | NLA_PUT_U32(skb, FRA_TABLE, rule->table); |
14c0b97d TG |
313 | frh->res1 = 0; |
314 | frh->res2 = 0; | |
315 | frh->action = rule->action; | |
316 | frh->flags = rule->flags; | |
317 | ||
318 | if (rule->ifname[0]) | |
319 | NLA_PUT_STRING(skb, FRA_IFNAME, rule->ifname); | |
320 | ||
321 | if (rule->pref) | |
322 | NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref); | |
323 | ||
b8964ed9 TG |
324 | if (rule->mark) |
325 | NLA_PUT_U32(skb, FRA_FWMARK, rule->mark); | |
326 | ||
327 | if (rule->mark_mask || rule->mark) | |
328 | NLA_PUT_U32(skb, FRA_FWMASK, rule->mark_mask); | |
329 | ||
14c0b97d TG |
330 | if (ops->fill(rule, skb, nlh, frh) < 0) |
331 | goto nla_put_failure; | |
332 | ||
333 | return nlmsg_end(skb, nlh); | |
334 | ||
335 | nla_put_failure: | |
336 | return nlmsg_cancel(skb, nlh); | |
337 | } | |
338 | ||
339 | int fib_rules_dump(struct sk_buff *skb, struct netlink_callback *cb, int family) | |
340 | { | |
341 | int idx = 0; | |
342 | struct fib_rule *rule; | |
343 | struct fib_rules_ops *ops; | |
344 | ||
345 | ops = lookup_rules_ops(family); | |
346 | if (ops == NULL) | |
347 | return -EAFNOSUPPORT; | |
348 | ||
349 | rcu_read_lock(); | |
350 | list_for_each_entry(rule, ops->rules_list, list) { | |
351 | if (idx < cb->args[0]) | |
352 | goto skip; | |
353 | ||
354 | if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).pid, | |
355 | cb->nlh->nlmsg_seq, RTM_NEWRULE, | |
356 | NLM_F_MULTI, ops) < 0) | |
357 | break; | |
358 | skip: | |
359 | idx++; | |
360 | } | |
361 | rcu_read_unlock(); | |
362 | cb->args[0] = idx; | |
363 | rules_ops_put(ops); | |
364 | ||
365 | return skb->len; | |
366 | } | |
367 | ||
368 | EXPORT_SYMBOL_GPL(fib_rules_dump); | |
369 | ||
370 | static void notify_rule_change(int event, struct fib_rule *rule, | |
c17084d2 TG |
371 | struct fib_rules_ops *ops, struct nlmsghdr *nlh, |
372 | u32 pid) | |
14c0b97d | 373 | { |
c17084d2 TG |
374 | struct sk_buff *skb; |
375 | int err = -ENOBUFS; | |
14c0b97d | 376 | |
c17084d2 | 377 | skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); |
14c0b97d | 378 | if (skb == NULL) |
c17084d2 TG |
379 | goto errout; |
380 | ||
381 | err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops); | |
382 | if (err < 0) { | |
14c0b97d | 383 | kfree_skb(skb); |
c17084d2 TG |
384 | goto errout; |
385 | } | |
386 | ||
387 | err = rtnl_notify(skb, pid, ops->nlgroup, nlh, GFP_KERNEL); | |
388 | errout: | |
389 | if (err < 0) | |
390 | rtnl_set_sk_err(ops->nlgroup, err); | |
14c0b97d TG |
391 | } |
392 | ||
393 | static void attach_rules(struct list_head *rules, struct net_device *dev) | |
394 | { | |
395 | struct fib_rule *rule; | |
396 | ||
397 | list_for_each_entry(rule, rules, list) { | |
398 | if (rule->ifindex == -1 && | |
399 | strcmp(dev->name, rule->ifname) == 0) | |
400 | rule->ifindex = dev->ifindex; | |
401 | } | |
402 | } | |
403 | ||
404 | static void detach_rules(struct list_head *rules, struct net_device *dev) | |
405 | { | |
406 | struct fib_rule *rule; | |
407 | ||
408 | list_for_each_entry(rule, rules, list) | |
409 | if (rule->ifindex == dev->ifindex) | |
410 | rule->ifindex = -1; | |
411 | } | |
412 | ||
413 | ||
414 | static int fib_rules_event(struct notifier_block *this, unsigned long event, | |
415 | void *ptr) | |
416 | { | |
417 | struct net_device *dev = ptr; | |
418 | struct fib_rules_ops *ops; | |
419 | ||
420 | ASSERT_RTNL(); | |
421 | rcu_read_lock(); | |
422 | ||
423 | switch (event) { | |
424 | case NETDEV_REGISTER: | |
425 | list_for_each_entry(ops, &rules_ops, list) | |
426 | attach_rules(ops->rules_list, dev); | |
427 | break; | |
428 | ||
429 | case NETDEV_UNREGISTER: | |
430 | list_for_each_entry(ops, &rules_ops, list) | |
431 | detach_rules(ops->rules_list, dev); | |
432 | break; | |
433 | } | |
434 | ||
435 | rcu_read_unlock(); | |
436 | ||
437 | return NOTIFY_DONE; | |
438 | } | |
439 | ||
440 | static struct notifier_block fib_rules_notifier = { | |
441 | .notifier_call = fib_rules_event, | |
442 | }; | |
443 | ||
444 | static int __init fib_rules_init(void) | |
445 | { | |
446 | return register_netdevice_notifier(&fib_rules_notifier); | |
447 | } | |
448 | ||
449 | subsys_initcall(fib_rules_init); |