1/*
2 * lwtunnel	Infrastructure for light weight tunnels like mpls
3 *
4 * Authors:	Roopa Prabhu, <roopa@cumulusnetworks.com>
5 *
6 *		This program is free software; you can redistribute it and/or
7 *		modify it under the terms of the GNU General Public License
8 *		as published by the Free Software Foundation; either version
9 *		2 of the License, or (at your option) any later version.
10 *
11 */
12
13#include <linux/capability.h>
14#include <linux/module.h>
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/slab.h>
18#include <linux/uaccess.h>
19#include <linux/skbuff.h>
20#include <linux/netdevice.h>
21#include <linux/lwtunnel.h>
22#include <linux/in.h>
23#include <linux/init.h>
24#include <linux/err.h>
25
26#include <net/lwtunnel.h>
27#include <net/rtnetlink.h>
28#include <net/ip6_fib.h>
29
30struct lwtunnel_state *lwtunnel_state_alloc(int encap_len)
31{
32	struct lwtunnel_state *lws;
33
34	lws = kzalloc(sizeof(*lws) + encap_len, GFP_ATOMIC);
35
36	return lws;
37}
38EXPORT_SYMBOL(lwtunnel_state_alloc);
39
40static const struct lwtunnel_encap_ops __rcu *
41		lwtun_encaps[LWTUNNEL_ENCAP_MAX + 1] __read_mostly;
42
43int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *ops,
44			   unsigned int num)
45{
46	if (num > LWTUNNEL_ENCAP_MAX)
47		return -ERANGE;
48
49	return !cmpxchg((const struct lwtunnel_encap_ops **)
50			&lwtun_encaps[num],
51			NULL, ops) ? 0 : -1;
52}
53EXPORT_SYMBOL(lwtunnel_encap_add_ops);
54
55int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *ops,
56			   unsigned int encap_type)
57{
58	int ret;
59
60	if (encap_type == LWTUNNEL_ENCAP_NONE ||
61	    encap_type > LWTUNNEL_ENCAP_MAX)
62		return -ERANGE;
63
64	ret = (cmpxchg((const struct lwtunnel_encap_ops **)
65		       &lwtun_encaps[encap_type],
66		       ops, NULL) == ops) ? 0 : -1;
67
68	synchronize_net();
69
70	return ret;
71}
72EXPORT_SYMBOL(lwtunnel_encap_del_ops);
73
74int lwtunnel_build_state(struct net_device *dev, u16 encap_type,
75			 struct nlattr *encap, unsigned int family,
76			 const void *cfg, struct lwtunnel_state **lws)
77{
78	const struct lwtunnel_encap_ops *ops;
79	int ret = -EINVAL;
80
81	if (encap_type == LWTUNNEL_ENCAP_NONE ||
82	    encap_type > LWTUNNEL_ENCAP_MAX)
83		return ret;
84
85	ret = -EOPNOTSUPP;
86	rcu_read_lock();
87	ops = rcu_dereference(lwtun_encaps[encap_type]);
88	if (likely(ops && ops->build_state))
89		ret = ops->build_state(dev, encap, family, cfg, lws);
90	rcu_read_unlock();
91
92	return ret;
93}
94EXPORT_SYMBOL(lwtunnel_build_state);
95
96int lwtunnel_fill_encap(struct sk_buff *skb, struct lwtunnel_state *lwtstate)
97{
98	const struct lwtunnel_encap_ops *ops;
99	struct nlattr *nest;
100	int ret = -EINVAL;
101
102	if (!lwtstate)
103		return 0;
104
105	if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
106	    lwtstate->type > LWTUNNEL_ENCAP_MAX)
107		return 0;
108
109	ret = -EOPNOTSUPP;
110	nest = nla_nest_start(skb, RTA_ENCAP);
111	rcu_read_lock();
112	ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
113	if (likely(ops && ops->fill_encap))
114		ret = ops->fill_encap(skb, lwtstate);
115	rcu_read_unlock();
116
117	if (ret)
118		goto nla_put_failure;
119	nla_nest_end(skb, nest);
120	ret = nla_put_u16(skb, RTA_ENCAP_TYPE, lwtstate->type);
121	if (ret)
122		goto nla_put_failure;
123
124	return 0;
125
126nla_put_failure:
127	nla_nest_cancel(skb, nest);
128
129	return (ret == -EOPNOTSUPP ? 0 : ret);
130}
131EXPORT_SYMBOL(lwtunnel_fill_encap);
132
133int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
134{
135	const struct lwtunnel_encap_ops *ops;
136	int ret = 0;
137
138	if (!lwtstate)
139		return 0;
140
141	if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
142	    lwtstate->type > LWTUNNEL_ENCAP_MAX)
143		return 0;
144
145	rcu_read_lock();
146	ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
147	if (likely(ops && ops->get_encap_size))
148		ret = nla_total_size(ops->get_encap_size(lwtstate));
149	rcu_read_unlock();
150
151	return ret;
152}
153EXPORT_SYMBOL(lwtunnel_get_encap_size);
154
155int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
156{
157	const struct lwtunnel_encap_ops *ops;
158	int ret = 0;
159
160	if (!a && !b)
161		return 0;
162
163	if (!a || !b)
164		return 1;
165
166	if (a->type != b->type)
167		return 1;
168
169	if (a->type == LWTUNNEL_ENCAP_NONE ||
170	    a->type > LWTUNNEL_ENCAP_MAX)
171		return 0;
172
173	rcu_read_lock();
174	ops = rcu_dereference(lwtun_encaps[a->type]);
175	if (likely(ops && ops->cmp_encap))
176		ret = ops->cmp_encap(a, b);
177	rcu_read_unlock();
178
179	return ret;
180}
181EXPORT_SYMBOL(lwtunnel_cmp_encap);
182
183int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
184{
185	struct dst_entry *dst = skb_dst(skb);
186	const struct lwtunnel_encap_ops *ops;
187	struct lwtunnel_state *lwtstate;
188	int ret = -EINVAL;
189
190	if (!dst)
191		goto drop;
192	lwtstate = dst->lwtstate;
193
194	if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
195	    lwtstate->type > LWTUNNEL_ENCAP_MAX)
196		return 0;
197
198	ret = -EOPNOTSUPP;
199	rcu_read_lock();
200	ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
201	if (likely(ops && ops->output))
202		ret = ops->output(net, sk, skb);
203	rcu_read_unlock();
204
205	if (ret == -EOPNOTSUPP)
206		goto drop;
207
208	return ret;
209
210drop:
211	kfree_skb(skb);
212
213	return ret;
214}
215EXPORT_SYMBOL(lwtunnel_output);
216
217int lwtunnel_input(struct sk_buff *skb)
218{
219	struct dst_entry *dst = skb_dst(skb);
220	const struct lwtunnel_encap_ops *ops;
221	struct lwtunnel_state *lwtstate;
222	int ret = -EINVAL;
223
224	if (!dst)
225		goto drop;
226	lwtstate = dst->lwtstate;
227
228	if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
229	    lwtstate->type > LWTUNNEL_ENCAP_MAX)
230		return 0;
231
232	ret = -EOPNOTSUPP;
233	rcu_read_lock();
234	ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
235	if (likely(ops && ops->input))
236		ret = ops->input(skb);
237	rcu_read_unlock();
238
239	if (ret == -EOPNOTSUPP)
240		goto drop;
241
242	return ret;
243
244drop:
245	kfree_skb(skb);
246
247	return ret;
248}
249EXPORT_SYMBOL(lwtunnel_input);
250