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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 | ||
3dfbcc41 TG |
110 | static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops, |
111 | struct flowi *fl, int flags) | |
112 | { | |
113 | int ret = 0; | |
114 | ||
115 | if (rule->ifindex && (rule->ifindex != fl->iif)) | |
116 | goto out; | |
117 | ||
118 | if ((rule->mark ^ fl->mark) & rule->mark_mask) | |
119 | goto out; | |
120 | ||
121 | ret = ops->match(rule, fl, flags); | |
122 | out: | |
123 | return (rule->flags & FIB_RULE_INVERT) ? !ret : ret; | |
124 | } | |
125 | ||
14c0b97d TG |
126 | int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl, |
127 | int flags, struct fib_lookup_arg *arg) | |
128 | { | |
129 | struct fib_rule *rule; | |
130 | int err; | |
131 | ||
132 | rcu_read_lock(); | |
133 | ||
134 | list_for_each_entry_rcu(rule, ops->rules_list, list) { | |
3dfbcc41 | 135 | if (!fib_rule_match(rule, ops, fl, flags)) |
14c0b97d TG |
136 | continue; |
137 | ||
138 | err = ops->action(rule, fl, flags, arg); | |
139 | if (err != -EAGAIN) { | |
140 | fib_rule_get(rule); | |
141 | arg->rule = rule; | |
142 | goto out; | |
143 | } | |
144 | } | |
145 | ||
146 | err = -ENETUNREACH; | |
147 | out: | |
148 | rcu_read_unlock(); | |
149 | ||
150 | return err; | |
151 | } | |
152 | ||
153 | EXPORT_SYMBOL_GPL(fib_rules_lookup); | |
154 | ||
155 | int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) | |
156 | { | |
157 | struct fib_rule_hdr *frh = nlmsg_data(nlh); | |
158 | struct fib_rules_ops *ops = NULL; | |
159 | struct fib_rule *rule, *r, *last = NULL; | |
160 | struct nlattr *tb[FRA_MAX+1]; | |
161 | int err = -EINVAL; | |
162 | ||
163 | if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) | |
164 | goto errout; | |
165 | ||
166 | ops = lookup_rules_ops(frh->family); | |
167 | if (ops == NULL) { | |
168 | err = EAFNOSUPPORT; | |
169 | goto errout; | |
170 | } | |
171 | ||
172 | err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy); | |
173 | if (err < 0) | |
174 | goto errout; | |
175 | ||
14c0b97d TG |
176 | rule = kzalloc(ops->rule_size, GFP_KERNEL); |
177 | if (rule == NULL) { | |
178 | err = -ENOMEM; | |
179 | goto errout; | |
180 | } | |
181 | ||
182 | if (tb[FRA_PRIORITY]) | |
183 | rule->pref = nla_get_u32(tb[FRA_PRIORITY]); | |
184 | ||
185 | if (tb[FRA_IFNAME]) { | |
186 | struct net_device *dev; | |
187 | ||
188 | rule->ifindex = -1; | |
5176f91e | 189 | nla_strlcpy(rule->ifname, tb[FRA_IFNAME], IFNAMSIZ); |
14c0b97d TG |
190 | dev = __dev_get_by_name(rule->ifname); |
191 | if (dev) | |
192 | rule->ifindex = dev->ifindex; | |
193 | } | |
194 | ||
b8964ed9 TG |
195 | if (tb[FRA_FWMARK]) { |
196 | rule->mark = nla_get_u32(tb[FRA_FWMARK]); | |
197 | if (rule->mark) | |
198 | /* compatibility: if the mark value is non-zero all bits | |
199 | * are compared unless a mask is explicitly specified. | |
200 | */ | |
201 | rule->mark_mask = 0xFFFFFFFF; | |
202 | } | |
203 | ||
204 | if (tb[FRA_FWMASK]) | |
205 | rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]); | |
206 | ||
14c0b97d TG |
207 | rule->action = frh->action; |
208 | rule->flags = frh->flags; | |
9e762a4a | 209 | rule->table = frh_get_table(frh, tb); |
14c0b97d TG |
210 | |
211 | if (!rule->pref && ops->default_pref) | |
212 | rule->pref = ops->default_pref(); | |
213 | ||
214 | err = ops->configure(rule, skb, nlh, frh, tb); | |
215 | if (err < 0) | |
216 | goto errout_free; | |
217 | ||
218 | list_for_each_entry(r, ops->rules_list, list) { | |
219 | if (r->pref > rule->pref) | |
220 | break; | |
221 | last = r; | |
222 | } | |
223 | ||
224 | fib_rule_get(rule); | |
225 | ||
226 | if (last) | |
227 | list_add_rcu(&rule->list, &last->list); | |
228 | else | |
229 | list_add_rcu(&rule->list, ops->rules_list); | |
230 | ||
c17084d2 | 231 | notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).pid); |
14c0b97d TG |
232 | rules_ops_put(ops); |
233 | return 0; | |
234 | ||
235 | errout_free: | |
236 | kfree(rule); | |
237 | errout: | |
238 | rules_ops_put(ops); | |
239 | return err; | |
240 | } | |
241 | ||
242 | int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) | |
243 | { | |
244 | struct fib_rule_hdr *frh = nlmsg_data(nlh); | |
245 | struct fib_rules_ops *ops = NULL; | |
246 | struct fib_rule *rule; | |
247 | struct nlattr *tb[FRA_MAX+1]; | |
248 | int err = -EINVAL; | |
249 | ||
250 | if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) | |
251 | goto errout; | |
252 | ||
253 | ops = lookup_rules_ops(frh->family); | |
254 | if (ops == NULL) { | |
255 | err = EAFNOSUPPORT; | |
256 | goto errout; | |
257 | } | |
258 | ||
259 | err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy); | |
260 | if (err < 0) | |
261 | goto errout; | |
262 | ||
263 | list_for_each_entry(rule, ops->rules_list, list) { | |
264 | if (frh->action && (frh->action != rule->action)) | |
265 | continue; | |
266 | ||
9e762a4a | 267 | if (frh->table && (frh_get_table(frh, tb) != rule->table)) |
14c0b97d TG |
268 | continue; |
269 | ||
270 | if (tb[FRA_PRIORITY] && | |
271 | (rule->pref != nla_get_u32(tb[FRA_PRIORITY]))) | |
272 | continue; | |
273 | ||
274 | if (tb[FRA_IFNAME] && | |
275 | nla_strcmp(tb[FRA_IFNAME], rule->ifname)) | |
276 | continue; | |
277 | ||
b8964ed9 TG |
278 | if (tb[FRA_FWMARK] && |
279 | (rule->mark != nla_get_u32(tb[FRA_FWMARK]))) | |
280 | continue; | |
281 | ||
282 | if (tb[FRA_FWMASK] && | |
283 | (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK]))) | |
284 | continue; | |
285 | ||
14c0b97d TG |
286 | if (!ops->compare(rule, frh, tb)) |
287 | continue; | |
288 | ||
289 | if (rule->flags & FIB_RULE_PERMANENT) { | |
290 | err = -EPERM; | |
291 | goto errout; | |
292 | } | |
293 | ||
294 | list_del_rcu(&rule->list); | |
295 | synchronize_rcu(); | |
c17084d2 TG |
296 | notify_rule_change(RTM_DELRULE, rule, ops, nlh, |
297 | NETLINK_CB(skb).pid); | |
14c0b97d TG |
298 | fib_rule_put(rule); |
299 | rules_ops_put(ops); | |
300 | return 0; | |
301 | } | |
302 | ||
303 | err = -ENOENT; | |
304 | errout: | |
305 | rules_ops_put(ops); | |
306 | return err; | |
307 | } | |
308 | ||
339bf98f TG |
309 | static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops, |
310 | struct fib_rule *rule) | |
311 | { | |
312 | size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr)) | |
313 | + nla_total_size(IFNAMSIZ) /* FRA_IFNAME */ | |
314 | + nla_total_size(4) /* FRA_PRIORITY */ | |
315 | + nla_total_size(4) /* FRA_TABLE */ | |
316 | + nla_total_size(4) /* FRA_FWMARK */ | |
317 | + nla_total_size(4); /* FRA_FWMASK */ | |
318 | ||
319 | if (ops->nlmsg_payload) | |
320 | payload += ops->nlmsg_payload(rule); | |
321 | ||
322 | return payload; | |
323 | } | |
324 | ||
14c0b97d TG |
325 | static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule, |
326 | u32 pid, u32 seq, int type, int flags, | |
327 | struct fib_rules_ops *ops) | |
328 | { | |
329 | struct nlmsghdr *nlh; | |
330 | struct fib_rule_hdr *frh; | |
331 | ||
332 | nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags); | |
333 | if (nlh == NULL) | |
334 | return -1; | |
335 | ||
336 | frh = nlmsg_data(nlh); | |
337 | frh->table = rule->table; | |
9e762a4a | 338 | NLA_PUT_U32(skb, FRA_TABLE, rule->table); |
14c0b97d TG |
339 | frh->res1 = 0; |
340 | frh->res2 = 0; | |
341 | frh->action = rule->action; | |
342 | frh->flags = rule->flags; | |
343 | ||
344 | if (rule->ifname[0]) | |
345 | NLA_PUT_STRING(skb, FRA_IFNAME, rule->ifname); | |
346 | ||
347 | if (rule->pref) | |
348 | NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref); | |
349 | ||
b8964ed9 TG |
350 | if (rule->mark) |
351 | NLA_PUT_U32(skb, FRA_FWMARK, rule->mark); | |
352 | ||
353 | if (rule->mark_mask || rule->mark) | |
354 | NLA_PUT_U32(skb, FRA_FWMASK, rule->mark_mask); | |
355 | ||
14c0b97d TG |
356 | if (ops->fill(rule, skb, nlh, frh) < 0) |
357 | goto nla_put_failure; | |
358 | ||
359 | return nlmsg_end(skb, nlh); | |
360 | ||
361 | nla_put_failure: | |
362 | return nlmsg_cancel(skb, nlh); | |
363 | } | |
364 | ||
365 | int fib_rules_dump(struct sk_buff *skb, struct netlink_callback *cb, int family) | |
366 | { | |
367 | int idx = 0; | |
368 | struct fib_rule *rule; | |
369 | struct fib_rules_ops *ops; | |
370 | ||
371 | ops = lookup_rules_ops(family); | |
372 | if (ops == NULL) | |
373 | return -EAFNOSUPPORT; | |
374 | ||
375 | rcu_read_lock(); | |
376 | list_for_each_entry(rule, ops->rules_list, list) { | |
377 | if (idx < cb->args[0]) | |
378 | goto skip; | |
379 | ||
380 | if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).pid, | |
381 | cb->nlh->nlmsg_seq, RTM_NEWRULE, | |
382 | NLM_F_MULTI, ops) < 0) | |
383 | break; | |
384 | skip: | |
385 | idx++; | |
386 | } | |
387 | rcu_read_unlock(); | |
388 | cb->args[0] = idx; | |
389 | rules_ops_put(ops); | |
390 | ||
391 | return skb->len; | |
392 | } | |
393 | ||
394 | EXPORT_SYMBOL_GPL(fib_rules_dump); | |
395 | ||
396 | static void notify_rule_change(int event, struct fib_rule *rule, | |
c17084d2 TG |
397 | struct fib_rules_ops *ops, struct nlmsghdr *nlh, |
398 | u32 pid) | |
14c0b97d | 399 | { |
c17084d2 TG |
400 | struct sk_buff *skb; |
401 | int err = -ENOBUFS; | |
14c0b97d | 402 | |
339bf98f | 403 | skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL); |
14c0b97d | 404 | if (skb == NULL) |
c17084d2 TG |
405 | goto errout; |
406 | ||
407 | err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops); | |
339bf98f TG |
408 | /* failure implies BUG in fib_rule_nlmsg_size() */ |
409 | BUG_ON(err < 0); | |
c17084d2 TG |
410 | |
411 | err = rtnl_notify(skb, pid, ops->nlgroup, nlh, GFP_KERNEL); | |
412 | errout: | |
413 | if (err < 0) | |
414 | rtnl_set_sk_err(ops->nlgroup, err); | |
14c0b97d TG |
415 | } |
416 | ||
417 | static void attach_rules(struct list_head *rules, struct net_device *dev) | |
418 | { | |
419 | struct fib_rule *rule; | |
420 | ||
421 | list_for_each_entry(rule, rules, list) { | |
422 | if (rule->ifindex == -1 && | |
423 | strcmp(dev->name, rule->ifname) == 0) | |
424 | rule->ifindex = dev->ifindex; | |
425 | } | |
426 | } | |
427 | ||
428 | static void detach_rules(struct list_head *rules, struct net_device *dev) | |
429 | { | |
430 | struct fib_rule *rule; | |
431 | ||
432 | list_for_each_entry(rule, rules, list) | |
433 | if (rule->ifindex == dev->ifindex) | |
434 | rule->ifindex = -1; | |
435 | } | |
436 | ||
437 | ||
438 | static int fib_rules_event(struct notifier_block *this, unsigned long event, | |
439 | void *ptr) | |
440 | { | |
441 | struct net_device *dev = ptr; | |
442 | struct fib_rules_ops *ops; | |
443 | ||
444 | ASSERT_RTNL(); | |
445 | rcu_read_lock(); | |
446 | ||
447 | switch (event) { | |
448 | case NETDEV_REGISTER: | |
449 | list_for_each_entry(ops, &rules_ops, list) | |
450 | attach_rules(ops->rules_list, dev); | |
451 | break; | |
452 | ||
453 | case NETDEV_UNREGISTER: | |
454 | list_for_each_entry(ops, &rules_ops, list) | |
455 | detach_rules(ops->rules_list, dev); | |
456 | break; | |
457 | } | |
458 | ||
459 | rcu_read_unlock(); | |
460 | ||
461 | return NOTIFY_DONE; | |
462 | } | |
463 | ||
464 | static struct notifier_block fib_rules_notifier = { | |
465 | .notifier_call = fib_rules_event, | |
466 | }; | |
467 | ||
468 | static int __init fib_rules_init(void) | |
469 | { | |
470 | return register_netdevice_notifier(&fib_rules_notifier); | |
471 | } | |
472 | ||
473 | subsys_initcall(fib_rules_init); |