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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 | ||
11 | #include <linux/config.h> | |
12 | #include <linux/types.h> | |
13 | #include <linux/kernel.h> | |
14 | #include <linux/list.h> | |
15 | #include <net/fib_rules.h> | |
16 | ||
17 | static LIST_HEAD(rules_ops); | |
18 | static DEFINE_SPINLOCK(rules_mod_lock); | |
19 | ||
20 | static void notify_rule_change(int event, struct fib_rule *rule, | |
21 | struct fib_rules_ops *ops); | |
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 | ||
122 | if (!ops->match(rule, fl, flags)) | |
123 | continue; | |
124 | ||
125 | err = ops->action(rule, fl, flags, arg); | |
126 | if (err != -EAGAIN) { | |
127 | fib_rule_get(rule); | |
128 | arg->rule = rule; | |
129 | goto out; | |
130 | } | |
131 | } | |
132 | ||
133 | err = -ENETUNREACH; | |
134 | out: | |
135 | rcu_read_unlock(); | |
136 | ||
137 | return err; | |
138 | } | |
139 | ||
140 | EXPORT_SYMBOL_GPL(fib_rules_lookup); | |
141 | ||
142 | int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) | |
143 | { | |
144 | struct fib_rule_hdr *frh = nlmsg_data(nlh); | |
145 | struct fib_rules_ops *ops = NULL; | |
146 | struct fib_rule *rule, *r, *last = NULL; | |
147 | struct nlattr *tb[FRA_MAX+1]; | |
148 | int err = -EINVAL; | |
149 | ||
150 | if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) | |
151 | goto errout; | |
152 | ||
153 | ops = lookup_rules_ops(frh->family); | |
154 | if (ops == NULL) { | |
155 | err = EAFNOSUPPORT; | |
156 | goto errout; | |
157 | } | |
158 | ||
159 | err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy); | |
160 | if (err < 0) | |
161 | goto errout; | |
162 | ||
163 | if (tb[FRA_IFNAME] && nla_len(tb[FRA_IFNAME]) > IFNAMSIZ) | |
164 | goto errout; | |
165 | ||
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; | |
179 | if (nla_strlcpy(rule->ifname, tb[FRA_IFNAME], | |
180 | IFNAMSIZ) >= IFNAMSIZ) | |
181 | goto errout_free; | |
182 | ||
183 | dev = __dev_get_by_name(rule->ifname); | |
184 | if (dev) | |
185 | rule->ifindex = dev->ifindex; | |
186 | } | |
187 | ||
188 | rule->action = frh->action; | |
189 | rule->flags = frh->flags; | |
9e762a4a | 190 | rule->table = frh_get_table(frh, tb); |
14c0b97d TG |
191 | |
192 | if (!rule->pref && ops->default_pref) | |
193 | rule->pref = ops->default_pref(); | |
194 | ||
195 | err = ops->configure(rule, skb, nlh, frh, tb); | |
196 | if (err < 0) | |
197 | goto errout_free; | |
198 | ||
199 | list_for_each_entry(r, ops->rules_list, list) { | |
200 | if (r->pref > rule->pref) | |
201 | break; | |
202 | last = r; | |
203 | } | |
204 | ||
205 | fib_rule_get(rule); | |
206 | ||
207 | if (last) | |
208 | list_add_rcu(&rule->list, &last->list); | |
209 | else | |
210 | list_add_rcu(&rule->list, ops->rules_list); | |
211 | ||
212 | notify_rule_change(RTM_NEWRULE, rule, ops); | |
213 | rules_ops_put(ops); | |
214 | return 0; | |
215 | ||
216 | errout_free: | |
217 | kfree(rule); | |
218 | errout: | |
219 | rules_ops_put(ops); | |
220 | return err; | |
221 | } | |
222 | ||
223 | int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) | |
224 | { | |
225 | struct fib_rule_hdr *frh = nlmsg_data(nlh); | |
226 | struct fib_rules_ops *ops = NULL; | |
227 | struct fib_rule *rule; | |
228 | struct nlattr *tb[FRA_MAX+1]; | |
229 | int err = -EINVAL; | |
230 | ||
231 | if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) | |
232 | goto errout; | |
233 | ||
234 | ops = lookup_rules_ops(frh->family); | |
235 | if (ops == NULL) { | |
236 | err = EAFNOSUPPORT; | |
237 | goto errout; | |
238 | } | |
239 | ||
240 | err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy); | |
241 | if (err < 0) | |
242 | goto errout; | |
243 | ||
244 | list_for_each_entry(rule, ops->rules_list, list) { | |
245 | if (frh->action && (frh->action != rule->action)) | |
246 | continue; | |
247 | ||
9e762a4a | 248 | if (frh->table && (frh_get_table(frh, tb) != rule->table)) |
14c0b97d TG |
249 | continue; |
250 | ||
251 | if (tb[FRA_PRIORITY] && | |
252 | (rule->pref != nla_get_u32(tb[FRA_PRIORITY]))) | |
253 | continue; | |
254 | ||
255 | if (tb[FRA_IFNAME] && | |
256 | nla_strcmp(tb[FRA_IFNAME], rule->ifname)) | |
257 | continue; | |
258 | ||
259 | if (!ops->compare(rule, frh, tb)) | |
260 | continue; | |
261 | ||
262 | if (rule->flags & FIB_RULE_PERMANENT) { | |
263 | err = -EPERM; | |
264 | goto errout; | |
265 | } | |
266 | ||
267 | list_del_rcu(&rule->list); | |
268 | synchronize_rcu(); | |
269 | notify_rule_change(RTM_DELRULE, rule, ops); | |
270 | fib_rule_put(rule); | |
271 | rules_ops_put(ops); | |
272 | return 0; | |
273 | } | |
274 | ||
275 | err = -ENOENT; | |
276 | errout: | |
277 | rules_ops_put(ops); | |
278 | return err; | |
279 | } | |
280 | ||
281 | static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule, | |
282 | u32 pid, u32 seq, int type, int flags, | |
283 | struct fib_rules_ops *ops) | |
284 | { | |
285 | struct nlmsghdr *nlh; | |
286 | struct fib_rule_hdr *frh; | |
287 | ||
288 | nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags); | |
289 | if (nlh == NULL) | |
290 | return -1; | |
291 | ||
292 | frh = nlmsg_data(nlh); | |
293 | frh->table = rule->table; | |
9e762a4a | 294 | NLA_PUT_U32(skb, FRA_TABLE, rule->table); |
14c0b97d TG |
295 | frh->res1 = 0; |
296 | frh->res2 = 0; | |
297 | frh->action = rule->action; | |
298 | frh->flags = rule->flags; | |
299 | ||
300 | if (rule->ifname[0]) | |
301 | NLA_PUT_STRING(skb, FRA_IFNAME, rule->ifname); | |
302 | ||
303 | if (rule->pref) | |
304 | NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref); | |
305 | ||
306 | if (ops->fill(rule, skb, nlh, frh) < 0) | |
307 | goto nla_put_failure; | |
308 | ||
309 | return nlmsg_end(skb, nlh); | |
310 | ||
311 | nla_put_failure: | |
312 | return nlmsg_cancel(skb, nlh); | |
313 | } | |
314 | ||
315 | int fib_rules_dump(struct sk_buff *skb, struct netlink_callback *cb, int family) | |
316 | { | |
317 | int idx = 0; | |
318 | struct fib_rule *rule; | |
319 | struct fib_rules_ops *ops; | |
320 | ||
321 | ops = lookup_rules_ops(family); | |
322 | if (ops == NULL) | |
323 | return -EAFNOSUPPORT; | |
324 | ||
325 | rcu_read_lock(); | |
326 | list_for_each_entry(rule, ops->rules_list, list) { | |
327 | if (idx < cb->args[0]) | |
328 | goto skip; | |
329 | ||
330 | if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).pid, | |
331 | cb->nlh->nlmsg_seq, RTM_NEWRULE, | |
332 | NLM_F_MULTI, ops) < 0) | |
333 | break; | |
334 | skip: | |
335 | idx++; | |
336 | } | |
337 | rcu_read_unlock(); | |
338 | cb->args[0] = idx; | |
339 | rules_ops_put(ops); | |
340 | ||
341 | return skb->len; | |
342 | } | |
343 | ||
344 | EXPORT_SYMBOL_GPL(fib_rules_dump); | |
345 | ||
346 | static void notify_rule_change(int event, struct fib_rule *rule, | |
347 | struct fib_rules_ops *ops) | |
348 | { | |
349 | int size = nlmsg_total_size(sizeof(struct fib_rule_hdr) + 128); | |
350 | struct sk_buff *skb = alloc_skb(size, GFP_KERNEL); | |
351 | ||
352 | if (skb == NULL) | |
353 | netlink_set_err(rtnl, 0, ops->nlgroup, ENOBUFS); | |
354 | else if (fib_nl_fill_rule(skb, rule, 0, 0, event, 0, ops) < 0) { | |
355 | kfree_skb(skb); | |
356 | netlink_set_err(rtnl, 0, ops->nlgroup, EINVAL); | |
357 | } else | |
358 | netlink_broadcast(rtnl, skb, 0, ops->nlgroup, GFP_KERNEL); | |
359 | } | |
360 | ||
361 | static void attach_rules(struct list_head *rules, struct net_device *dev) | |
362 | { | |
363 | struct fib_rule *rule; | |
364 | ||
365 | list_for_each_entry(rule, rules, list) { | |
366 | if (rule->ifindex == -1 && | |
367 | strcmp(dev->name, rule->ifname) == 0) | |
368 | rule->ifindex = dev->ifindex; | |
369 | } | |
370 | } | |
371 | ||
372 | static void detach_rules(struct list_head *rules, struct net_device *dev) | |
373 | { | |
374 | struct fib_rule *rule; | |
375 | ||
376 | list_for_each_entry(rule, rules, list) | |
377 | if (rule->ifindex == dev->ifindex) | |
378 | rule->ifindex = -1; | |
379 | } | |
380 | ||
381 | ||
382 | static int fib_rules_event(struct notifier_block *this, unsigned long event, | |
383 | void *ptr) | |
384 | { | |
385 | struct net_device *dev = ptr; | |
386 | struct fib_rules_ops *ops; | |
387 | ||
388 | ASSERT_RTNL(); | |
389 | rcu_read_lock(); | |
390 | ||
391 | switch (event) { | |
392 | case NETDEV_REGISTER: | |
393 | list_for_each_entry(ops, &rules_ops, list) | |
394 | attach_rules(ops->rules_list, dev); | |
395 | break; | |
396 | ||
397 | case NETDEV_UNREGISTER: | |
398 | list_for_each_entry(ops, &rules_ops, list) | |
399 | detach_rules(ops->rules_list, dev); | |
400 | break; | |
401 | } | |
402 | ||
403 | rcu_read_unlock(); | |
404 | ||
405 | return NOTIFY_DONE; | |
406 | } | |
407 | ||
408 | static struct notifier_block fib_rules_notifier = { | |
409 | .notifier_call = fib_rules_event, | |
410 | }; | |
411 | ||
412 | static int __init fib_rules_init(void) | |
413 | { | |
414 | return register_netdevice_notifier(&fib_rules_notifier); | |
415 | } | |
416 | ||
417 | subsys_initcall(fib_rules_init); |