4429b1a1fe5fe2528318b7417e539279548d9988
[linux-2.6.git] / net / ipv6 / xfrm6_policy.c
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 <asm/bug.h>
15 #include <linux/compiler.h>
16 #include <linux/config.h>
17 #include <linux/netdevice.h>
18 #include <net/addrconf.h>
19 #include <net/xfrm.h>
20 #include <net/ip.h>
21 #include <net/ipv6.h>
22 #include <net/ip6_route.h>
23
24 static struct dst_ops xfrm6_dst_ops;
25 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
26
27 static struct xfrm_type_map xfrm6_type_map = { .lock = RW_LOCK_UNLOCKED };
28
29 static int xfrm6_dst_lookup(struct xfrm_dst **dst, struct flowi *fl)
30 {
31         int err = 0;
32         *dst = (struct xfrm_dst*)ip6_route_output(NULL, fl);
33         if (!*dst)
34                 err = -ENETUNREACH;
35         return err;
36 }
37
38 static struct dst_entry *
39 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
40 {
41         struct dst_entry *dst;
42
43         /* Still not clear if we should set fl->fl6_{src,dst}... */
44         read_lock_bh(&policy->lock);
45         for (dst = policy->bundles; dst; dst = dst->next) {
46                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
47                 struct in6_addr fl_dst_prefix, fl_src_prefix;
48
49                 ipv6_addr_prefix(&fl_dst_prefix,
50                                  &fl->fl6_dst,
51                                  xdst->u.rt6.rt6i_dst.plen);
52                 ipv6_addr_prefix(&fl_src_prefix,
53                                  &fl->fl6_src,
54                                  xdst->u.rt6.rt6i_src.plen);
55                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
56                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
57                     xfrm_bundle_ok(xdst, fl, AF_INET6)) {
58                         dst_clone(dst);
59                         break;
60                 }
61         }
62         read_unlock_bh(&policy->lock);
63         return dst;
64 }
65
66 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
67  * all the metrics... Shortly, bundle a bundle.
68  */
69
70 static int
71 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
72                       struct flowi *fl, struct dst_entry **dst_p)
73 {
74         struct dst_entry *dst, *dst_prev;
75         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
76         struct rt6_info *rt  = rt0;
77         struct in6_addr *remote = &fl->fl6_dst;
78         struct in6_addr *local  = &fl->fl6_src;
79         struct flowi fl_tunnel = {
80                 .nl_u = {
81                         .ip6_u = {
82                                 .saddr = *local,
83                                 .daddr = *remote
84                         }
85                 }
86         };
87         int i;
88         int err = 0;
89         int header_len = 0;
90         int trailer_len = 0;
91
92         dst = dst_prev = NULL;
93         dst_hold(&rt->u.dst);
94
95         for (i = 0; i < nx; i++) {
96                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
97                 struct xfrm_dst *xdst;
98                 int tunnel = 0;
99
100                 if (unlikely(dst1 == NULL)) {
101                         err = -ENOBUFS;
102                         dst_release(&rt->u.dst);
103                         goto error;
104                 }
105
106                 if (!dst)
107                         dst = dst1;
108                 else {
109                         dst_prev->child = dst1;
110                         dst1->flags |= DST_NOHASH;
111                         dst_clone(dst1);
112                 }
113
114                 xdst = (struct xfrm_dst *)dst1;
115                 xdst->route = &rt->u.dst;
116
117                 dst1->next = dst_prev;
118                 dst_prev = dst1;
119                 if (xfrm[i]->props.mode) {
120                         remote = (struct in6_addr*)&xfrm[i]->id.daddr;
121                         local  = (struct in6_addr*)&xfrm[i]->props.saddr;
122                         tunnel = 1;
123                 }
124                 header_len += xfrm[i]->props.header_len;
125                 trailer_len += xfrm[i]->props.trailer_len;
126
127                 if (tunnel) {
128                         ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
129                         ipv6_addr_copy(&fl_tunnel.fl6_src, local);
130                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
131                                               &fl_tunnel, AF_INET6);
132                         if (err)
133                                 goto error;
134                 } else
135                         dst_hold(&rt->u.dst);
136         }
137
138         dst_prev->child = &rt->u.dst;
139         dst->path = &rt->u.dst;
140
141         *dst_p = dst;
142         dst = dst_prev;
143
144         dst_prev = *dst_p;
145         i = 0;
146         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
147                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
148
149                 dst_prev->xfrm = xfrm[i++];
150                 dst_prev->dev = rt->u.dst.dev;
151                 if (rt->u.dst.dev)
152                         dev_hold(rt->u.dst.dev);
153                 dst_prev->obsolete      = -1;
154                 dst_prev->flags        |= DST_HOST;
155                 dst_prev->lastuse       = jiffies;
156                 dst_prev->header_len    = header_len;
157                 dst_prev->trailer_len   = trailer_len;
158                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
159
160                 /* Copy neighbour for reachability confirmation */
161                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
162                 dst_prev->input         = rt->u.dst.input;
163                 dst_prev->output        = xfrm6_output;
164                 /* Sheit... I remember I did this right. Apparently,
165                  * it was magically lost, so this code needs audit */
166                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
167                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
168                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
169                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
170                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway)); 
171                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
172                 x->u.rt6.rt6i_src      = rt0->rt6i_src; 
173                 x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
174                 in6_dev_hold(rt0->rt6i_idev);
175                 header_len -= x->u.dst.xfrm->props.header_len;
176                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
177         }
178
179         xfrm_init_pmtu(dst);
180         return 0;
181
182 error:
183         if (dst)
184                 dst_free(dst);
185         return err;
186 }
187
188 static inline void
189 _decode_session6(struct sk_buff *skb, struct flowi *fl)
190 {
191         u16 offset = sizeof(struct ipv6hdr);
192         struct ipv6hdr *hdr = skb->nh.ipv6h;
193         struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
194         u8 nexthdr = skb->nh.ipv6h->nexthdr;
195
196         memset(fl, 0, sizeof(struct flowi));
197         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
198         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
199
200         while (pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data)) {
201                 switch (nexthdr) {
202                 case NEXTHDR_ROUTING:
203                 case NEXTHDR_HOP:
204                 case NEXTHDR_DEST:
205                         offset += ipv6_optlen(exthdr);
206                         nexthdr = exthdr->nexthdr;
207                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
208                         break;
209
210                 case IPPROTO_UDP:
211                 case IPPROTO_TCP:
212                 case IPPROTO_SCTP:
213                         if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
214                                 u16 *ports = (u16 *)exthdr;
215
216                                 fl->fl_ip_sport = ports[0];
217                                 fl->fl_ip_dport = ports[1];
218                         }
219                         fl->proto = nexthdr;
220                         return;
221
222                 case IPPROTO_ICMPV6:
223                         if (pskb_may_pull(skb, skb->nh.raw + offset + 2 - skb->data)) {
224                                 u8 *icmp = (u8 *)exthdr;
225
226                                 fl->fl_icmp_type = icmp[0];
227                                 fl->fl_icmp_code = icmp[1];
228                         }
229                         fl->proto = nexthdr;
230                         return;
231
232                 /* XXX Why are there these headers? */
233                 case IPPROTO_AH:
234                 case IPPROTO_ESP:
235                 case IPPROTO_COMP:
236                 default:
237                         fl->fl_ipsec_spi = 0;
238                         fl->proto = nexthdr;
239                         return;
240                 };
241         }
242 }
243
244 static inline int xfrm6_garbage_collect(void)
245 {
246         read_lock(&xfrm6_policy_afinfo.lock);
247         xfrm6_policy_afinfo.garbage_collect();
248         read_unlock(&xfrm6_policy_afinfo.lock);
249         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
250 }
251
252 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
253 {
254         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
255         struct dst_entry *path = xdst->route;
256
257         path->ops->update_pmtu(path, mtu);
258 }
259
260 static void xfrm6_dst_destroy(struct dst_entry *dst)
261 {
262         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
263
264         if (likely(xdst->u.rt6.rt6i_idev))
265                 in6_dev_put(xdst->u.rt6.rt6i_idev);
266         xfrm_dst_destroy(xdst);
267 }
268
269 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
270                              int unregister)
271 {
272         struct xfrm_dst *xdst;
273
274         if (!unregister)
275                 return;
276
277         xdst = (struct xfrm_dst *)dst;
278         if (xdst->u.rt6.rt6i_idev->dev == dev) {
279                 struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
280                 BUG_ON(!loopback_idev);
281
282                 do {
283                         in6_dev_put(xdst->u.rt6.rt6i_idev);
284                         xdst->u.rt6.rt6i_idev = loopback_idev;
285                         in6_dev_hold(loopback_idev);
286                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
287                 } while (xdst->u.dst.xfrm);
288
289                 __in6_dev_put(loopback_idev);
290         }
291
292         xfrm_dst_ifdown(dst, dev);
293 }
294
295 static struct dst_ops xfrm6_dst_ops = {
296         .family =               AF_INET6,
297         .protocol =             __constant_htons(ETH_P_IPV6),
298         .gc =                   xfrm6_garbage_collect,
299         .update_pmtu =          xfrm6_update_pmtu,
300         .destroy =              xfrm6_dst_destroy,
301         .ifdown =               xfrm6_dst_ifdown,
302         .gc_thresh =            1024,
303         .entry_size =           sizeof(struct xfrm_dst),
304 };
305
306 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
307         .family =               AF_INET6,
308         .lock =                 RW_LOCK_UNLOCKED,
309         .type_map =             &xfrm6_type_map,
310         .dst_ops =              &xfrm6_dst_ops,
311         .dst_lookup =           xfrm6_dst_lookup,
312         .find_bundle =          __xfrm6_find_bundle,
313         .bundle_create =        __xfrm6_bundle_create,
314         .decode_session =       _decode_session6,
315 };
316
317 static void __init xfrm6_policy_init(void)
318 {
319         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
320 }
321
322 static void xfrm6_policy_fini(void)
323 {
324         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
325 }
326
327 void __init xfrm6_init(void)
328 {
329         xfrm6_policy_init();
330         xfrm6_state_init();
331 }
332
333 void xfrm6_fini(void)
334 {
335         //xfrm6_input_fini();
336         xfrm6_policy_fini();
337         xfrm6_state_fini();
338 }