xref: /openbmc/linux/net/ipv6/xfrm6_policy.c (revision 13996378e6585fb25e582afe7489bf52dde78deb) 
1 /*
2  * xfrm6_policy.c: based on xfrm4_policy.c
3  *
4  * Authors:
5  *	Mitsuru KANDA @USAGI
6  * 	Kazunori MIYAZAWA @USAGI
7  * 	Kunihiro Ishiguro <kunihiro@ipinfusion.com>
8  * 		IPv6 support
9  * 	YOSHIFUJI Hideaki
10  * 		Split up af-specific portion
11  *
12  */
13 
14 #include <linux/compiler.h>
15 #include <linux/netdevice.h>
16 #include <net/addrconf.h>
17 #include <net/xfrm.h>
18 #include <net/ip.h>
19 #include <net/ipv6.h>
20 #include <net/ip6_route.h>
21 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
22 #include <net/mip6.h>
23 #endif
24 
25 static struct dst_ops xfrm6_dst_ops;
26 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
27 
28 static int xfrm6_dst_lookup(struct xfrm_dst **xdst, struct flowi *fl)
29 {
30 	struct dst_entry *dst = ip6_route_output(NULL, fl);
31 	int err = dst->error;
32 	if (!err)
33 		*xdst = (struct xfrm_dst *) dst;
34 	else
35 		dst_release(dst);
36 	return err;
37 }
38 
39 static int xfrm6_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
40 {
41 	struct rt6_info *rt;
42 	struct flowi fl_tunnel = {
43 		.nl_u = {
44 			.ip6_u = {
45 				.daddr = *(struct in6_addr *)&daddr->a6,
46 			},
47 		},
48 	};
49 
50 	if (!xfrm6_dst_lookup((struct xfrm_dst **)&rt, &fl_tunnel)) {
51 		ipv6_get_saddr(&rt->u.dst, (struct in6_addr *)&daddr->a6,
52 			       (struct in6_addr *)&saddr->a6);
53 		dst_release(&rt->u.dst);
54 		return 0;
55 	}
56 	return -EHOSTUNREACH;
57 }
58 
59 static struct dst_entry *
60 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
61 {
62 	struct dst_entry *dst;
63 
64 	/* Still not clear if we should set fl->fl6_{src,dst}... */
65 	read_lock_bh(&policy->lock);
66 	for (dst = policy->bundles; dst; dst = dst->next) {
67 		struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
68 		struct in6_addr fl_dst_prefix, fl_src_prefix;
69 
70 		ipv6_addr_prefix(&fl_dst_prefix,
71 				 &fl->fl6_dst,
72 				 xdst->u.rt6.rt6i_dst.plen);
73 		ipv6_addr_prefix(&fl_src_prefix,
74 				 &fl->fl6_src,
75 				 xdst->u.rt6.rt6i_src.plen);
76 		if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
77 		    ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
78 		    xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
79 				   (xdst->u.rt6.rt6i_dst.plen != 128 ||
80 				    xdst->u.rt6.rt6i_src.plen != 128))) {
81 			dst_clone(dst);
82 			break;
83 		}
84 	}
85 	read_unlock_bh(&policy->lock);
86 	return dst;
87 }
88 
89 static inline struct in6_addr*
90 __xfrm6_bundle_addr_remote(struct xfrm_state *x, struct in6_addr *addr)
91 {
92 	return (x->type->remote_addr) ?
93 		(struct in6_addr*)x->type->remote_addr(x, (xfrm_address_t *)addr) :
94 		(struct in6_addr*)&x->id.daddr;
95 }
96 
97 static inline struct in6_addr*
98 __xfrm6_bundle_addr_local(struct xfrm_state *x, struct in6_addr *addr)
99 {
100 	return (x->type->local_addr) ?
101 		(struct in6_addr*)x->type->local_addr(x, (xfrm_address_t *)addr) :
102 		(struct in6_addr*)&x->props.saddr;
103 }
104 
105 static inline void
106 __xfrm6_bundle_len_inc(int *len, int *nflen, struct xfrm_state *x)
107 {
108 	if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
109 		*nflen += x->props.header_len;
110 	else
111 		*len += x->props.header_len;
112 }
113 
114 static inline void
115 __xfrm6_bundle_len_dec(int *len, int *nflen, struct xfrm_state *x)
116 {
117 	if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
118 		*nflen -= x->props.header_len;
119 	else
120 		*len -= x->props.header_len;
121 }
122 
123 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
124  * all the metrics... Shortly, bundle a bundle.
125  */
126 
127 static int
128 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
129 		      struct flowi *fl, struct dst_entry **dst_p)
130 {
131 	struct dst_entry *dst, *dst_prev;
132 	struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
133 	struct rt6_info *rt  = rt0;
134 	struct flowi fl_tunnel = {
135 		.nl_u = {
136 			.ip6_u = {
137 				.saddr = fl->fl6_src,
138 				.daddr = fl->fl6_dst,
139 			}
140 		}
141 	};
142 	int i;
143 	int err = 0;
144 	int header_len = 0;
145 	int nfheader_len = 0;
146 	int trailer_len = 0;
147 
148 	dst = dst_prev = NULL;
149 	dst_hold(&rt->u.dst);
150 
151 	for (i = 0; i < nx; i++) {
152 		struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
153 		struct xfrm_dst *xdst;
154 
155 		if (unlikely(dst1 == NULL)) {
156 			err = -ENOBUFS;
157 			dst_release(&rt->u.dst);
158 			goto error;
159 		}
160 
161 		if (!dst)
162 			dst = dst1;
163 		else {
164 			dst_prev->child = dst1;
165 			dst1->flags |= DST_NOHASH;
166 			dst_clone(dst1);
167 		}
168 
169 		xdst = (struct xfrm_dst *)dst1;
170 		xdst->route = &rt->u.dst;
171 		xdst->genid = xfrm[i]->genid;
172 		if (rt->rt6i_node)
173 			xdst->route_cookie = rt->rt6i_node->fn_sernum;
174 
175 		dst1->next = dst_prev;
176 		dst_prev = dst1;
177 
178 		__xfrm6_bundle_len_inc(&header_len, &nfheader_len, xfrm[i]);
179 		trailer_len += xfrm[i]->props.trailer_len;
180 
181 		if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
182 			unsigned short encap_family = xfrm[i]->props.family;
183 			switch(encap_family) {
184 			case AF_INET:
185 				fl_tunnel.fl4_dst = xfrm[i]->id.daddr.a4;
186 				fl_tunnel.fl4_src = xfrm[i]->props.saddr.a4;
187 				break;
188 			case AF_INET6:
189 				ipv6_addr_copy(&fl_tunnel.fl6_dst, __xfrm6_bundle_addr_remote(xfrm[i], &fl->fl6_dst));
190 
191 				ipv6_addr_copy(&fl_tunnel.fl6_src, __xfrm6_bundle_addr_local(xfrm[i], &fl->fl6_src));
192 				break;
193 			default:
194 				BUG_ON(1);
195 			}
196 
197 			err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
198 					      &fl_tunnel, encap_family);
199 			if (err)
200 				goto error;
201 		} else
202 			dst_hold(&rt->u.dst);
203 	}
204 
205 	dst_prev->child = &rt->u.dst;
206 	dst->path = &rt->u.dst;
207 	if (rt->rt6i_node)
208 		((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
209 
210 	*dst_p = dst;
211 	dst = dst_prev;
212 
213 	dst_prev = *dst_p;
214 	i = 0;
215 	for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
216 		struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
217 
218 		dst_prev->xfrm = xfrm[i++];
219 		dst_prev->dev = rt->u.dst.dev;
220 		if (rt->u.dst.dev)
221 			dev_hold(rt->u.dst.dev);
222 		dst_prev->obsolete	= -1;
223 		dst_prev->flags	       |= DST_HOST;
224 		dst_prev->lastuse	= jiffies;
225 		dst_prev->header_len	= header_len;
226 		dst_prev->nfheader_len	= nfheader_len;
227 		dst_prev->trailer_len	= trailer_len;
228 		memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
229 
230 		/* Copy neighbour for reachability confirmation */
231 		dst_prev->neighbour	= neigh_clone(rt->u.dst.neighbour);
232 		dst_prev->input		= rt->u.dst.input;
233 		dst_prev->output = dst_prev->xfrm->outer_mode->afinfo->output;
234 		/* Sheit... I remember I did this right. Apparently,
235 		 * it was magically lost, so this code needs audit */
236 		x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
237 		x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
238 		x->u.rt6.rt6i_node     = rt0->rt6i_node;
239 		x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
240 		memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
241 		x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
242 		x->u.rt6.rt6i_src      = rt0->rt6i_src;
243 		x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
244 		in6_dev_hold(rt0->rt6i_idev);
245 		__xfrm6_bundle_len_dec(&header_len, &nfheader_len, x->u.dst.xfrm);
246 		trailer_len -= x->u.dst.xfrm->props.trailer_len;
247 	}
248 
249 	xfrm_init_pmtu(dst);
250 	return 0;
251 
252 error:
253 	if (dst)
254 		dst_free(dst);
255 	return err;
256 }
257 
258 static inline void
259 _decode_session6(struct sk_buff *skb, struct flowi *fl)
260 {
261 	u16 offset = skb_network_header_len(skb);
262 	struct ipv6hdr *hdr = ipv6_hdr(skb);
263 	struct ipv6_opt_hdr *exthdr;
264 	const unsigned char *nh = skb_network_header(skb);
265 	u8 nexthdr = nh[IP6CB(skb)->nhoff];
266 
267 	memset(fl, 0, sizeof(struct flowi));
268 	ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
269 	ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
270 
271 	while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
272 		nh = skb_network_header(skb);
273 		exthdr = (struct ipv6_opt_hdr *)(nh + offset);
274 
275 		switch (nexthdr) {
276 		case NEXTHDR_ROUTING:
277 		case NEXTHDR_HOP:
278 		case NEXTHDR_DEST:
279 			offset += ipv6_optlen(exthdr);
280 			nexthdr = exthdr->nexthdr;
281 			exthdr = (struct ipv6_opt_hdr *)(nh + offset);
282 			break;
283 
284 		case IPPROTO_UDP:
285 		case IPPROTO_UDPLITE:
286 		case IPPROTO_TCP:
287 		case IPPROTO_SCTP:
288 		case IPPROTO_DCCP:
289 			if (pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
290 				__be16 *ports = (__be16 *)exthdr;
291 
292 				fl->fl_ip_sport = ports[0];
293 				fl->fl_ip_dport = ports[1];
294 			}
295 			fl->proto = nexthdr;
296 			return;
297 
298 		case IPPROTO_ICMPV6:
299 			if (pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
300 				u8 *icmp = (u8 *)exthdr;
301 
302 				fl->fl_icmp_type = icmp[0];
303 				fl->fl_icmp_code = icmp[1];
304 			}
305 			fl->proto = nexthdr;
306 			return;
307 
308 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
309 		case IPPROTO_MH:
310 			if (pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
311 				struct ip6_mh *mh;
312 				mh = (struct ip6_mh *)exthdr;
313 
314 				fl->fl_mh_type = mh->ip6mh_type;
315 			}
316 			fl->proto = nexthdr;
317 			return;
318 #endif
319 
320 		/* XXX Why are there these headers? */
321 		case IPPROTO_AH:
322 		case IPPROTO_ESP:
323 		case IPPROTO_COMP:
324 		default:
325 			fl->fl_ipsec_spi = 0;
326 			fl->proto = nexthdr;
327 			return;
328 		}
329 	}
330 }
331 
332 static inline int xfrm6_garbage_collect(void)
333 {
334 	xfrm6_policy_afinfo.garbage_collect();
335 	return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
336 }
337 
338 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
339 {
340 	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
341 	struct dst_entry *path = xdst->route;
342 
343 	path->ops->update_pmtu(path, mtu);
344 }
345 
346 static void xfrm6_dst_destroy(struct dst_entry *dst)
347 {
348 	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
349 
350 	if (likely(xdst->u.rt6.rt6i_idev))
351 		in6_dev_put(xdst->u.rt6.rt6i_idev);
352 	xfrm_dst_destroy(xdst);
353 }
354 
355 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
356 			     int unregister)
357 {
358 	struct xfrm_dst *xdst;
359 
360 	if (!unregister)
361 		return;
362 
363 	xdst = (struct xfrm_dst *)dst;
364 	if (xdst->u.rt6.rt6i_idev->dev == dev) {
365 		struct inet6_dev *loopback_idev = in6_dev_get(init_net.loopback_dev);
366 		BUG_ON(!loopback_idev);
367 
368 		do {
369 			in6_dev_put(xdst->u.rt6.rt6i_idev);
370 			xdst->u.rt6.rt6i_idev = loopback_idev;
371 			in6_dev_hold(loopback_idev);
372 			xdst = (struct xfrm_dst *)xdst->u.dst.child;
373 		} while (xdst->u.dst.xfrm);
374 
375 		__in6_dev_put(loopback_idev);
376 	}
377 
378 	xfrm_dst_ifdown(dst, dev);
379 }
380 
381 static struct dst_ops xfrm6_dst_ops = {
382 	.family =		AF_INET6,
383 	.protocol =		__constant_htons(ETH_P_IPV6),
384 	.gc =			xfrm6_garbage_collect,
385 	.update_pmtu =		xfrm6_update_pmtu,
386 	.destroy =		xfrm6_dst_destroy,
387 	.ifdown =		xfrm6_dst_ifdown,
388 	.gc_thresh =		1024,
389 	.entry_size =		sizeof(struct xfrm_dst),
390 };
391 
392 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
393 	.family =		AF_INET6,
394 	.dst_ops =		&xfrm6_dst_ops,
395 	.dst_lookup =		xfrm6_dst_lookup,
396 	.get_saddr = 		xfrm6_get_saddr,
397 	.find_bundle =		__xfrm6_find_bundle,
398 	.bundle_create =	__xfrm6_bundle_create,
399 	.decode_session =	_decode_session6,
400 };
401 
402 static void __init xfrm6_policy_init(void)
403 {
404 	xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
405 }
406 
407 static void xfrm6_policy_fini(void)
408 {
409 	xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
410 }
411 
412 void __init xfrm6_init(void)
413 {
414 	xfrm6_policy_init();
415 	xfrm6_state_init();
416 }
417 
418 void xfrm6_fini(void)
419 {
420 	//xfrm6_input_fini();
421 	xfrm6_policy_fini();
422 	xfrm6_state_fini();
423 }
424