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(xfrm6_tunnel_spi, SLAB_HWCACHE_ALIGN);
359 if (!xfrm6_tunnel_spi_kmem)
360 return -ENOMEM;
361 rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
362 if (rv < 0)
363 goto out_pernet;
364 rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
365 if (rv < 0)
366 goto out_type;
367 rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
368 if (rv < 0)
369 goto out_xfrm6;
370 rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
371 if (rv < 0)
372 goto out_xfrm46;
373 return 0;
374
375 out_xfrm46:
376 xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
377 out_xfrm6:
378 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
379 out_type:
380 unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
381 out_pernet:
382 kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
383 return rv;
384 }
385
xfrm6_tunnel_fini(void)386 static void __exit xfrm6_tunnel_fini(void)
387 {
388 xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
389 xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
390 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
391 unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
392 /* Someone maybe has gotten the xfrm6_tunnel_spi.
393 * So need to wait it.
394 */
395 rcu_barrier();
396 kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
397 }
398
399 module_init(xfrm6_tunnel_init);
400 module_exit(xfrm6_tunnel_fini);
401 MODULE_DESCRIPTION("IPv6 XFRM tunnel driver");
402 MODULE_LICENSE("GPL");
403 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);
404