xref: /openbmc/linux/net/ipv6/xfrm6_tunnel.c (revision 25ec92cd)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C)2003,2004 USAGI/WIDE Project
4  *
5  * Authors	Mitsuru KANDA  <mk@linux-ipv6.org>
6  *		YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
7  *
8  * Based on net/ipv4/xfrm4_tunnel.c
9  */
10 #include <linux/module.h>
11 #include <linux/xfrm.h>
12 #include <linux/slab.h>
13 #include <linux/rculist.h>
14 #include <net/ip.h>
15 #include <net/xfrm.h>
16 #include <net/ipv6.h>
17 #include <linux/ipv6.h>
18 #include <linux/icmpv6.h>
19 #include <linux/mutex.h>
20 #include <net/netns/generic.h>
21 
22 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
23 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
24 
25 #define XFRM6_TUNNEL_SPI_MIN	1
26 #define XFRM6_TUNNEL_SPI_MAX	0xffffffff
27 
28 struct xfrm6_tunnel_net {
29 	struct hlist_head spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
30 	struct hlist_head spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
31 	u32 spi;
32 };
33 
34 static unsigned int xfrm6_tunnel_net_id __read_mostly;
xfrm6_tunnel_pernet(struct net * net)35 static inline struct xfrm6_tunnel_net *xfrm6_tunnel_pernet(struct net *net)
36 {
37 	return net_generic(net, xfrm6_tunnel_net_id);
38 }
39 
40 /*
41  * xfrm_tunnel_spi things are for allocating unique id ("spi")
42  * per xfrm_address_t.
43  */
44 struct xfrm6_tunnel_spi {
45 	struct hlist_node	list_byaddr;
46 	struct hlist_node	list_byspi;
47 	xfrm_address_t		addr;
48 	u32			spi;
49 	refcount_t		refcnt;
50 	struct rcu_head		rcu_head;
51 };
52 
53 static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
54 
55 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
56 
xfrm6_tunnel_spi_hash_byaddr(const xfrm_address_t * addr)57 static inline unsigned int xfrm6_tunnel_spi_hash_byaddr(const xfrm_address_t *addr)
58 {
59 	unsigned int h;
60 
61 	h = ipv6_addr_hash((const struct in6_addr *)addr);
62 	h ^= h >> 16;
63 	h ^= h >> 8;
64 	h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
65 
66 	return h;
67 }
68 
xfrm6_tunnel_spi_hash_byspi(u32 spi)69 static inline unsigned int xfrm6_tunnel_spi_hash_byspi(u32 spi)
70 {
71 	return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
72 }
73 
__xfrm6_tunnel_spi_lookup(struct net * net,const xfrm_address_t * saddr)74 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
75 {
76 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
77 	struct xfrm6_tunnel_spi *x6spi;
78 
79 	hlist_for_each_entry_rcu(x6spi,
80 			     &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
81 			     list_byaddr, lockdep_is_held(&xfrm6_tunnel_spi_lock)) {
82 		if (xfrm6_addr_equal(&x6spi->addr, saddr))
83 			return x6spi;
84 	}
85 
86 	return NULL;
87 }
88 
xfrm6_tunnel_spi_lookup(struct net * net,const xfrm_address_t * saddr)89 __be32 xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
90 {
91 	struct xfrm6_tunnel_spi *x6spi;
92 	u32 spi;
93 
94 	rcu_read_lock_bh();
95 	x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
96 	spi = x6spi ? x6spi->spi : 0;
97 	rcu_read_unlock_bh();
98 	return htonl(spi);
99 }
100 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
101 
__xfrm6_tunnel_spi_check(struct net * net,u32 spi)102 static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
103 {
104 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
105 	struct xfrm6_tunnel_spi *x6spi;
106 	int index = xfrm6_tunnel_spi_hash_byspi(spi);
107 
108 	hlist_for_each_entry(x6spi,
109 			     &xfrm6_tn->spi_byspi[index],
110 			     list_byspi) {
111 		if (x6spi->spi == spi)
112 			return -1;
113 	}
114 	return index;
115 }
116 
__xfrm6_tunnel_alloc_spi(struct net * net,xfrm_address_t * saddr)117 static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
118 {
119 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
120 	u32 spi;
121 	struct xfrm6_tunnel_spi *x6spi;
122 	int index;
123 
124 	if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
125 	    xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
126 		xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
127 	else
128 		xfrm6_tn->spi++;
129 
130 	for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
131 		index = __xfrm6_tunnel_spi_check(net, spi);
132 		if (index >= 0)
133 			goto alloc_spi;
134 
135 		if (spi == XFRM6_TUNNEL_SPI_MAX)
136 			break;
137 	}
138 	for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
139 		index = __xfrm6_tunnel_spi_check(net, spi);
140 		if (index >= 0)
141 			goto alloc_spi;
142 	}
143 	spi = 0;
144 	goto out;
145 alloc_spi:
146 	xfrm6_tn->spi = spi;
147 	x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
148 	if (!x6spi)
149 		goto out;
150 
151 	memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
152 	x6spi->spi = spi;
153 	refcount_set(&x6spi->refcnt, 1);
154 
155 	hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
156 
157 	index = xfrm6_tunnel_spi_hash_byaddr(saddr);
158 	hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
159 out:
160 	return spi;
161 }
162 
xfrm6_tunnel_alloc_spi(struct net * net,xfrm_address_t * saddr)163 __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
164 {
165 	struct xfrm6_tunnel_spi *x6spi;
166 	u32 spi;
167 
168 	spin_lock_bh(&xfrm6_tunnel_spi_lock);
169 	x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
170 	if (x6spi) {
171 		refcount_inc(&x6spi->refcnt);
172 		spi = x6spi->spi;
173 	} else
174 		spi = __xfrm6_tunnel_alloc_spi(net, saddr);
175 	spin_unlock_bh(&xfrm6_tunnel_spi_lock);
176 
177 	return htonl(spi);
178 }
179 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
180 
x6spi_destroy_rcu(struct rcu_head * head)181 static void x6spi_destroy_rcu(struct rcu_head *head)
182 {
183 	kmem_cache_free(xfrm6_tunnel_spi_kmem,
184 			container_of(head, struct xfrm6_tunnel_spi, rcu_head));
185 }
186 
xfrm6_tunnel_free_spi(struct net * net,xfrm_address_t * saddr)187 static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
188 {
189 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
190 	struct xfrm6_tunnel_spi *x6spi;
191 	struct hlist_node *n;
192 
193 	spin_lock_bh(&xfrm6_tunnel_spi_lock);
194 
195 	hlist_for_each_entry_safe(x6spi, n,
196 				  &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
197 				  list_byaddr)
198 	{
199 		if (xfrm6_addr_equal(&x6spi->addr, saddr)) {
200 			if (refcount_dec_and_test(&x6spi->refcnt)) {
201 				hlist_del_rcu(&x6spi->list_byaddr);
202 				hlist_del_rcu(&x6spi->list_byspi);
203 				call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
204 				break;
205 			}
206 		}
207 	}
208 	spin_unlock_bh(&xfrm6_tunnel_spi_lock);
209 }
210 
xfrm6_tunnel_output(struct xfrm_state * x,struct sk_buff * skb)211 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
212 {
213 	skb_push(skb, -skb_network_offset(skb));
214 	return 0;
215 }
216 
xfrm6_tunnel_input(struct xfrm_state * x,struct sk_buff * skb)217 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
218 {
219 	return skb_network_header(skb)[IP6CB(skb)->nhoff];
220 }
221 
xfrm6_tunnel_rcv(struct sk_buff * skb)222 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
223 {
224 	struct net *net = dev_net(skb->dev);
225 	const struct ipv6hdr *iph = ipv6_hdr(skb);
226 	__be32 spi;
227 
228 	spi = xfrm6_tunnel_spi_lookup(net, (const xfrm_address_t *)&iph->saddr);
229 	return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi, NULL);
230 }
231 
xfrm6_tunnel_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)232 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
233 			    u8 type, u8 code, int offset, __be32 info)
234 {
235 	/* xfrm6_tunnel native err handling */
236 	switch (type) {
237 	case ICMPV6_DEST_UNREACH:
238 		switch (code) {
239 		case ICMPV6_NOROUTE:
240 		case ICMPV6_ADM_PROHIBITED:
241 		case ICMPV6_NOT_NEIGHBOUR:
242 		case ICMPV6_ADDR_UNREACH:
243 		case ICMPV6_PORT_UNREACH:
244 		default:
245 			break;
246 		}
247 		break;
248 	case ICMPV6_PKT_TOOBIG:
249 		break;
250 	case ICMPV6_TIME_EXCEED:
251 		switch (code) {
252 		case ICMPV6_EXC_HOPLIMIT:
253 			break;
254 		case ICMPV6_EXC_FRAGTIME:
255 		default:
256 			break;
257 		}
258 		break;
259 	case ICMPV6_PARAMPROB:
260 		switch (code) {
261 		case ICMPV6_HDR_FIELD: break;
262 		case ICMPV6_UNK_NEXTHDR: break;
263 		case ICMPV6_UNK_OPTION: break;
264 		}
265 		break;
266 	default:
267 		break;
268 	}
269 
270 	return 0;
271 }
272 
xfrm6_tunnel_init_state(struct xfrm_state * x,struct netlink_ext_ack * extack)273 static int xfrm6_tunnel_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
274 {
275 	if (x->props.mode != XFRM_MODE_TUNNEL) {
276 		NL_SET_ERR_MSG(extack, "IPv6 tunnel can only be used with tunnel mode");
277 		return -EINVAL;
278 	}
279 
280 	if (x->encap) {
281 		NL_SET_ERR_MSG(extack, "IPv6 tunnel is not compatible with encapsulation");
282 		return -EINVAL;
283 	}
284 
285 	x->props.header_len = sizeof(struct ipv6hdr);
286 
287 	return 0;
288 }
289 
xfrm6_tunnel_destroy(struct xfrm_state * x)290 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
291 {
292 	struct net *net = xs_net(x);
293 
294 	xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
295 }
296 
297 static const struct xfrm_type xfrm6_tunnel_type = {
298 	.owner          = THIS_MODULE,
299 	.proto		= IPPROTO_IPV6,
300 	.init_state	= xfrm6_tunnel_init_state,
301 	.destructor	= xfrm6_tunnel_destroy,
302 	.input		= xfrm6_tunnel_input,
303 	.output		= xfrm6_tunnel_output,
304 };
305 
306 static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
307 	.handler	= xfrm6_tunnel_rcv,
308 	.err_handler	= xfrm6_tunnel_err,
309 	.priority	= 3,
310 };
311 
312 static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
313 	.handler	= xfrm6_tunnel_rcv,
314 	.err_handler	= xfrm6_tunnel_err,
315 	.priority	= 3,
316 };
317 
xfrm6_tunnel_net_init(struct net * net)318 static int __net_init xfrm6_tunnel_net_init(struct net *net)
319 {
320 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
321 	unsigned int i;
322 
323 	for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
324 		INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
325 	for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
326 		INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
327 	xfrm6_tn->spi = 0;
328 
329 	return 0;
330 }
331 
xfrm6_tunnel_net_exit(struct net * net)332 static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
333 {
334 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
335 	unsigned int i;
336 
337 	xfrm_flush_gc();
338 	xfrm_state_flush(net, 0, false, true);
339 
340 	for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
341 		WARN_ON_ONCE(!hlist_empty(&xfrm6_tn->spi_byaddr[i]));
342 
343 	for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
344 		WARN_ON_ONCE(!hlist_empty(&xfrm6_tn->spi_byspi[i]));
345 }
346 
347 static struct pernet_operations xfrm6_tunnel_net_ops = {
348 	.init	= xfrm6_tunnel_net_init,
349 	.exit	= xfrm6_tunnel_net_exit,
350 	.id	= &xfrm6_tunnel_net_id,
351 	.size	= sizeof(struct xfrm6_tunnel_net),
352 };
353 
xfrm6_tunnel_init(void)354 static int __init xfrm6_tunnel_init(void)
355 {
356 	int rv;
357 
358 	xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
359 						  sizeof(struct xfrm6_tunnel_spi),
360 						  0, SLAB_HWCACHE_ALIGN,
361 						  NULL);
362 	if (!xfrm6_tunnel_spi_kmem)
363 		return -ENOMEM;
364 	rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
365 	if (rv < 0)
366 		goto out_pernet;
367 	rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
368 	if (rv < 0)
369 		goto out_type;
370 	rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
371 	if (rv < 0)
372 		goto out_xfrm6;
373 	rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
374 	if (rv < 0)
375 		goto out_xfrm46;
376 	return 0;
377 
378 out_xfrm46:
379 	xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
380 out_xfrm6:
381 	xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
382 out_type:
383 	unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
384 out_pernet:
385 	kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
386 	return rv;
387 }
388 
xfrm6_tunnel_fini(void)389 static void __exit xfrm6_tunnel_fini(void)
390 {
391 	xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
392 	xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
393 	xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
394 	unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
395 	/* Someone maybe has gotten the xfrm6_tunnel_spi.
396 	 * So need to wait it.
397 	 */
398 	rcu_barrier();
399 	kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
400 }
401 
402 module_init(xfrm6_tunnel_init);
403 module_exit(xfrm6_tunnel_fini);
404 MODULE_LICENSE("GPL");
405 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);
406