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