[mirror_ubuntu-zesty-kernel.git] / net / core / fib_rules.c

/*
 * net/core/fib_rules.c		Generic Routing Rules
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License as
 *	published by the Free Software Foundation, version 2.
 *
 * Authors:	Thomas Graf <tgraf@suug.ch>
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <net/fib_rules.h>

static LIST_HEAD(rules_ops);
static DEFINE_SPINLOCK(rules_mod_lock);

static void notify_rule_change(int event, struct fib_rule *rule,
			       struct fib_rules_ops *ops);

static struct fib_rules_ops *lookup_rules_ops(int family)
{
	struct fib_rules_ops *ops;

	rcu_read_lock();
	list_for_each_entry_rcu(ops, &rules_ops, list) {
		if (ops->family == family) {
			if (!try_module_get(ops->owner))
				ops = NULL;
			rcu_read_unlock();
			return ops;
		}
	}
	rcu_read_unlock();

	return NULL;
}

static void rules_ops_put(struct fib_rules_ops *ops)
{
	if (ops)
		module_put(ops->owner);
}

int fib_rules_register(struct fib_rules_ops *ops)
{
	int err = -EEXIST;
	struct fib_rules_ops *o;

	if (ops->rule_size < sizeof(struct fib_rule))
		return -EINVAL;

	if (ops->match == NULL || ops->configure == NULL ||
	    ops->compare == NULL || ops->fill == NULL ||
	    ops->action == NULL)
		return -EINVAL;

	spin_lock(&rules_mod_lock);
	list_for_each_entry(o, &rules_ops, list)
		if (ops->family == o->family)
			goto errout;

	list_add_tail_rcu(&ops->list, &rules_ops);
	err = 0;
errout:
	spin_unlock(&rules_mod_lock);

	return err;
}

EXPORT_SYMBOL_GPL(fib_rules_register);

static void cleanup_ops(struct fib_rules_ops *ops)
{
	struct fib_rule *rule, *tmp;

	list_for_each_entry_safe(rule, tmp, ops->rules_list, list) {
		list_del_rcu(&rule->list);
		fib_rule_put(rule);
	}
}

int fib_rules_unregister(struct fib_rules_ops *ops)
{
	int err = 0;
	struct fib_rules_ops *o;

	spin_lock(&rules_mod_lock);
	list_for_each_entry(o, &rules_ops, list) {
		if (o == ops) {
			list_del_rcu(&o->list);
			cleanup_ops(ops);
			goto out;
		}
	}

	err = -ENOENT;
out:
	spin_unlock(&rules_mod_lock);

	synchronize_rcu();

	return err;
}

EXPORT_SYMBOL_GPL(fib_rules_unregister);

int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
		     int flags, struct fib_lookup_arg *arg)
{
	struct fib_rule *rule;
	int err;

	rcu_read_lock();

	list_for_each_entry_rcu(rule, ops->rules_list, list) {
		if (rule->ifindex && (rule->ifindex != fl->iif))
			continue;

		if (!ops->match(rule, fl, flags))
			continue;

		err = ops->action(rule, fl, flags, arg);
		if (err != -EAGAIN) {
			fib_rule_get(rule);
			arg->rule = rule;
			goto out;
		}
	}

	err = -ENETUNREACH;
out:
	rcu_read_unlock();

	return err;
}

EXPORT_SYMBOL_GPL(fib_rules_lookup);

int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
{
	struct fib_rule_hdr *frh = nlmsg_data(nlh);
	struct fib_rules_ops *ops = NULL;
	struct fib_rule *rule, *r, *last = NULL;
	struct nlattr *tb[FRA_MAX+1];
	int err = -EINVAL;

	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
		goto errout;

	ops = lookup_rules_ops(frh->family);
	if (ops == NULL) {
		err = EAFNOSUPPORT;
		goto errout;
	}

	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
	if (err < 0)
		goto errout;

	if (tb[FRA_IFNAME] && nla_len(tb[FRA_IFNAME]) > IFNAMSIZ)
		goto errout;

	rule = kzalloc(ops->rule_size, GFP_KERNEL);
	if (rule == NULL) {
		err = -ENOMEM;
		goto errout;
	}

	if (tb[FRA_PRIORITY])
		rule->pref = nla_get_u32(tb[FRA_PRIORITY]);

	if (tb[FRA_IFNAME]) {
		struct net_device *dev;

		rule->ifindex = -1;
		if (nla_strlcpy(rule->ifname, tb[FRA_IFNAME],
				IFNAMSIZ) >= IFNAMSIZ)
			goto errout_free;

		dev = __dev_get_by_name(rule->ifname);
		if (dev)
			rule->ifindex = dev->ifindex;
	}

	rule->action = frh->action;
	rule->flags = frh->flags;
	rule->table = frh->table;

	if (!rule->pref && ops->default_pref)
		rule->pref = ops->default_pref();

	err = ops->configure(rule, skb, nlh, frh, tb);
	if (err < 0)
		goto errout_free;

	list_for_each_entry(r, ops->rules_list, list) {
		if (r->pref > rule->pref)
			break;
		last = r;
	}

	fib_rule_get(rule);

	if (last)
		list_add_rcu(&rule->list, &last->list);
	else
		list_add_rcu(&rule->list, ops->rules_list);

	notify_rule_change(RTM_NEWRULE, rule, ops);
	rules_ops_put(ops);
	return 0;

errout_free:
	kfree(rule);
errout:
	rules_ops_put(ops);
	return err;
}

int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
{
	struct fib_rule_hdr *frh = nlmsg_data(nlh);
	struct fib_rules_ops *ops = NULL;
	struct fib_rule *rule;
	struct nlattr *tb[FRA_MAX+1];
	int err = -EINVAL;

	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
		goto errout;

	ops = lookup_rules_ops(frh->family);
	if (ops == NULL) {
		err = EAFNOSUPPORT;
		goto errout;
	}

	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
	if (err < 0)
		goto errout;

	list_for_each_entry(rule, ops->rules_list, list) {
		if (frh->action && (frh->action != rule->action))
			continue;

		if (frh->table && (frh->table != rule->table))
			continue;

		if (tb[FRA_PRIORITY] &&
		    (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
			continue;

		if (tb[FRA_IFNAME] &&
		    nla_strcmp(tb[FRA_IFNAME], rule->ifname))
			continue;

		if (!ops->compare(rule, frh, tb))
			continue;

		if (rule->flags & FIB_RULE_PERMANENT) {
			err = -EPERM;
			goto errout;
		}

		list_del_rcu(&rule->list);
		synchronize_rcu();
		notify_rule_change(RTM_DELRULE, rule, ops);
		fib_rule_put(rule);
		rules_ops_put(ops);
		return 0;
	}

	err = -ENOENT;
errout:
	rules_ops_put(ops);
	return err;
}

static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
			    u32 pid, u32 seq, int type, int flags,
			    struct fib_rules_ops *ops)
{
	struct nlmsghdr *nlh;
	struct fib_rule_hdr *frh;

	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
	if (nlh == NULL)
		return -1;

	frh = nlmsg_data(nlh);
	frh->table = rule->table;
	frh->res1 = 0;
	frh->res2 = 0;
	frh->action = rule->action;
	frh->flags = rule->flags;

	if (rule->ifname[0])
		NLA_PUT_STRING(skb, FRA_IFNAME, rule->ifname);

	if (rule->pref)
		NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref);

	if (ops->fill(rule, skb, nlh, frh) < 0)
		goto nla_put_failure;

	return nlmsg_end(skb, nlh);

nla_put_failure:
	return nlmsg_cancel(skb, nlh);
}

int fib_rules_dump(struct sk_buff *skb, struct netlink_callback *cb, int family)
{
	int idx = 0;
	struct fib_rule *rule;
	struct fib_rules_ops *ops;

	ops = lookup_rules_ops(family);
	if (ops == NULL)
		return -EAFNOSUPPORT;

	rcu_read_lock();
	list_for_each_entry(rule, ops->rules_list, list) {
		if (idx < cb->args[0])
			goto skip;

		if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).pid,
				     cb->nlh->nlmsg_seq, RTM_NEWRULE,
				     NLM_F_MULTI, ops) < 0)
			break;
skip:
		idx++;
	}
	rcu_read_unlock();
	cb->args[0] = idx;
	rules_ops_put(ops);

	return skb->len;
}

EXPORT_SYMBOL_GPL(fib_rules_dump);

static void notify_rule_change(int event, struct fib_rule *rule,
			       struct fib_rules_ops *ops)
{
	int size = nlmsg_total_size(sizeof(struct fib_rule_hdr) + 128);
	struct sk_buff *skb = alloc_skb(size, GFP_KERNEL);

	if (skb == NULL)
		netlink_set_err(rtnl, 0, ops->nlgroup, ENOBUFS);
	else if (fib_nl_fill_rule(skb, rule, 0, 0, event, 0, ops) < 0) {
		kfree_skb(skb);
		netlink_set_err(rtnl, 0, ops->nlgroup, EINVAL);
	} else
		netlink_broadcast(rtnl, skb, 0, ops->nlgroup, GFP_KERNEL);
}

static void attach_rules(struct list_head *rules, struct net_device *dev)
{
	struct fib_rule *rule;

	list_for_each_entry(rule, rules, list) {
		if (rule->ifindex == -1 &&
		    strcmp(dev->name, rule->ifname) == 0)
			rule->ifindex = dev->ifindex;
	}
}

static void detach_rules(struct list_head *rules, struct net_device *dev)
{
	struct fib_rule *rule;

	list_for_each_entry(rule, rules, list)
		if (rule->ifindex == dev->ifindex)
			rule->ifindex = -1;
}


static int fib_rules_event(struct notifier_block *this, unsigned long event,
			    void *ptr)
{
	struct net_device *dev = ptr;
	struct fib_rules_ops *ops;

	ASSERT_RTNL();
	rcu_read_lock();

	switch (event) {
	case NETDEV_REGISTER:
		list_for_each_entry(ops, &rules_ops, list)
			attach_rules(ops->rules_list, dev);
		break;

	case NETDEV_UNREGISTER:
		list_for_each_entry(ops, &rules_ops, list)
			detach_rules(ops->rules_list, dev);
		break;
	}

	rcu_read_unlock();

	return NOTIFY_DONE;
}

static struct notifier_block fib_rules_notifier = {
	.notifier_call = fib_rules_event,
};

static int __init fib_rules_init(void)
{
	return register_netdevice_notifier(&fib_rules_notifier);
}

subsys_initcall(fib_rules_init);
Commit	Line	Data
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;
190	rule->table = frh->table;
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
248	if (frh->table && (frh->table != rule->table))
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;
294	frh->res1 = 0;
295	frh->res2 = 0;
296	frh->action = rule->action;
297	frh->flags = rule->flags;
298
299	if (rule->ifname[0])
300	NLA_PUT_STRING(skb, FRA_IFNAME, rule->ifname);
301
302	if (rule->pref)
303	NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref);
304
305	if (ops->fill(rule, skb, nlh, frh) < 0)
306	goto nla_put_failure;
307
308	return nlmsg_end(skb, nlh);
309
310	nla_put_failure:
311	return nlmsg_cancel(skb, nlh);
312	}
313
314	int fib_rules_dump(struct sk_buff skb, struct netlink_callback cb, int family)
315	{
316	int idx = 0;
317	struct fib_rule *rule;
318	struct fib_rules_ops *ops;
319
320	ops = lookup_rules_ops(family);
321	if (ops == NULL)
322	return -EAFNOSUPPORT;
323
324	rcu_read_lock();
325	list_for_each_entry(rule, ops->rules_list, list) {
326	if (idx < cb->args[0])
327	goto skip;
328
329	if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).pid,
330	cb->nlh->nlmsg_seq, RTM_NEWRULE,
331	NLM_F_MULTI, ops) < 0)
332	break;
333	skip:
334	idx++;
335	}
336	rcu_read_unlock();
337	cb->args[0] = idx;
338	rules_ops_put(ops);
339
340	return skb->len;
341	}
342
343	EXPORT_SYMBOL_GPL(fib_rules_dump);
344
345	static void notify_rule_change(int event, struct fib_rule *rule,
346	struct fib_rules_ops *ops)
347	{
348	int size = nlmsg_total_size(sizeof(struct fib_rule_hdr) + 128);
349	struct sk_buff *skb = alloc_skb(size, GFP_KERNEL);
350
351	if (skb == NULL)
352	netlink_set_err(rtnl, 0, ops->nlgroup, ENOBUFS);
353	else if (fib_nl_fill_rule(skb, rule, 0, 0, event, 0, ops) < 0) {
354	kfree_skb(skb);
355	netlink_set_err(rtnl, 0, ops->nlgroup, EINVAL);
356	} else
357	netlink_broadcast(rtnl, skb, 0, ops->nlgroup, GFP_KERNEL);
358	}
359
360	static void attach_rules(struct list_head rules, struct net_device dev)
361	{
362	struct fib_rule *rule;
363
364	list_for_each_entry(rule, rules, list) {
365	if (rule->ifindex == -1 &&
366	strcmp(dev->name, rule->ifname) == 0)
367	rule->ifindex = dev->ifindex;
368	}
369	}
370
371	static void detach_rules(struct list_head rules, struct net_device dev)
372	{
373	struct fib_rule *rule;
374
375	list_for_each_entry(rule, rules, list)
376	if (rule->ifindex == dev->ifindex)
377	rule->ifindex = -1;
378	}
379
380
381	static int fib_rules_event(struct notifier_block *this, unsigned long event,
382	void *ptr)
383	{
384	struct net_device *dev = ptr;
385	struct fib_rules_ops *ops;
386
387	ASSERT_RTNL();
388	rcu_read_lock();
389
390	switch (event) {
391	case NETDEV_REGISTER:
392	list_for_each_entry(ops, &rules_ops, list)
393	attach_rules(ops->rules_list, dev);
394	break;
395
396	case NETDEV_UNREGISTER:
397	list_for_each_entry(ops, &rules_ops, list)
398	detach_rules(ops->rules_list, dev);
399	break;
400	}
401
402	rcu_read_unlock();
403
404	return NOTIFY_DONE;
405	}
406
407	static struct notifier_block fib_rules_notifier = {
408	.notifier_call = fib_rules_event,
409	};
410
411	static int __init fib_rules_init(void)
412	{
413	return register_netdevice_notifier(&fib_rules_notifier);
414	}
415
416	subsys_initcall(fib_rules_init);