[XFRM]: Add XFRM_MODE_xxx for future use.
[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 <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
22 static struct dst_ops xfrm6_dst_ops;
23 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
24
25 static int xfrm6_dst_lookup(struct xfrm_dst **dst, struct flowi *fl)
26 {
27         int err = 0;
28         *dst = (struct xfrm_dst*)ip6_route_output(NULL, fl);
29         if (!*dst)
30                 err = -ENETUNREACH;
31         return err;
32 }
33
34 static struct dst_entry *
35 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
36 {
37         struct dst_entry *dst;
38
39         /* Still not clear if we should set fl->fl6_{src,dst}... */
40         read_lock_bh(&policy->lock);
41         for (dst = policy->bundles; dst; dst = dst->next) {
42                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
43                 struct in6_addr fl_dst_prefix, fl_src_prefix;
44
45                 ipv6_addr_prefix(&fl_dst_prefix,
46                                  &fl->fl6_dst,
47                                  xdst->u.rt6.rt6i_dst.plen);
48                 ipv6_addr_prefix(&fl_src_prefix,
49                                  &fl->fl6_src,
50                                  xdst->u.rt6.rt6i_src.plen);
51                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
52                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
53                     xfrm_bundle_ok(xdst, fl, AF_INET6)) {
54                         dst_clone(dst);
55                         break;
56                 }
57         }
58         read_unlock_bh(&policy->lock);
59         return dst;
60 }
61
62 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
63  * all the metrics... Shortly, bundle a bundle.
64  */
65
66 static int
67 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
68                       struct flowi *fl, struct dst_entry **dst_p)
69 {
70         struct dst_entry *dst, *dst_prev;
71         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
72         struct rt6_info *rt  = rt0;
73         struct in6_addr *remote = &fl->fl6_dst;
74         struct in6_addr *local  = &fl->fl6_src;
75         struct flowi fl_tunnel = {
76                 .nl_u = {
77                         .ip6_u = {
78                                 .saddr = *local,
79                                 .daddr = *remote
80                         }
81                 }
82         };
83         int i;
84         int err = 0;
85         int header_len = 0;
86         int trailer_len = 0;
87
88         dst = dst_prev = NULL;
89         dst_hold(&rt->u.dst);
90
91         for (i = 0; i < nx; i++) {
92                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
93                 struct xfrm_dst *xdst;
94                 int tunnel = 0;
95
96                 if (unlikely(dst1 == NULL)) {
97                         err = -ENOBUFS;
98                         dst_release(&rt->u.dst);
99                         goto error;
100                 }
101
102                 if (!dst)
103                         dst = dst1;
104                 else {
105                         dst_prev->child = dst1;
106                         dst1->flags |= DST_NOHASH;
107                         dst_clone(dst1);
108                 }
109
110                 xdst = (struct xfrm_dst *)dst1;
111                 xdst->route = &rt->u.dst;
112                 if (rt->rt6i_node)
113                         xdst->route_cookie = rt->rt6i_node->fn_sernum;
114
115                 dst1->next = dst_prev;
116                 dst_prev = dst1;
117                 if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
118                         remote = (struct in6_addr*)&xfrm[i]->id.daddr;
119                         local  = (struct in6_addr*)&xfrm[i]->props.saddr;
120                         tunnel = 1;
121                 }
122                 header_len += xfrm[i]->props.header_len;
123                 trailer_len += xfrm[i]->props.trailer_len;
124
125                 if (tunnel) {
126                         ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
127                         ipv6_addr_copy(&fl_tunnel.fl6_src, local);
128                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
129                                               &fl_tunnel, AF_INET6);
130                         if (err)
131                                 goto error;
132                 } else
133                         dst_hold(&rt->u.dst);
134         }
135
136         dst_prev->child = &rt->u.dst;
137         dst->path = &rt->u.dst;
138         if (rt->rt6i_node)
139                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
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 = skb->h.raw - skb->nh.raw;
192         struct ipv6hdr *hdr = skb->nh.ipv6h;
193         struct ipv6_opt_hdr *exthdr;
194         u8 nexthdr = skb->nh.raw[IP6CB(skb)->nhoff];
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                 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
202
203                 switch (nexthdr) {
204                 case NEXTHDR_ROUTING:
205                 case NEXTHDR_HOP:
206                 case NEXTHDR_DEST:
207                         offset += ipv6_optlen(exthdr);
208                         nexthdr = exthdr->nexthdr;
209                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
210                         break;
211
212                 case IPPROTO_UDP:
213                 case IPPROTO_TCP:
214                 case IPPROTO_SCTP:
215                 case IPPROTO_DCCP:
216                         if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
217                                 u16 *ports = (u16 *)exthdr;
218
219                                 fl->fl_ip_sport = ports[0];
220                                 fl->fl_ip_dport = ports[1];
221                         }
222                         fl->proto = nexthdr;
223                         return;
224
225                 case IPPROTO_ICMPV6:
226                         if (pskb_may_pull(skb, skb->nh.raw + offset + 2 - skb->data)) {
227                                 u8 *icmp = (u8 *)exthdr;
228
229                                 fl->fl_icmp_type = icmp[0];
230                                 fl->fl_icmp_code = icmp[1];
231                         }
232                         fl->proto = nexthdr;
233                         return;
234
235                 /* XXX Why are there these headers? */
236                 case IPPROTO_AH:
237                 case IPPROTO_ESP:
238                 case IPPROTO_COMP:
239                 default:
240                         fl->fl_ipsec_spi = 0;
241                         fl->proto = nexthdr;
242                         return;
243                 };
244         }
245 }
246
247 static inline int xfrm6_garbage_collect(void)
248 {
249         xfrm6_policy_afinfo.garbage_collect();
250         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
251 }
252
253 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
254 {
255         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
256         struct dst_entry *path = xdst->route;
257
258         path->ops->update_pmtu(path, mtu);
259 }
260
261 static void xfrm6_dst_destroy(struct dst_entry *dst)
262 {
263         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
264
265         if (likely(xdst->u.rt6.rt6i_idev))
266                 in6_dev_put(xdst->u.rt6.rt6i_idev);
267         xfrm_dst_destroy(xdst);
268 }
269
270 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
271                              int unregister)
272 {
273         struct xfrm_dst *xdst;
274
275         if (!unregister)
276                 return;
277
278         xdst = (struct xfrm_dst *)dst;
279         if (xdst->u.rt6.rt6i_idev->dev == dev) {
280                 struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
281                 BUG_ON(!loopback_idev);
282
283                 do {
284                         in6_dev_put(xdst->u.rt6.rt6i_idev);
285                         xdst->u.rt6.rt6i_idev = loopback_idev;
286                         in6_dev_hold(loopback_idev);
287                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
288                 } while (xdst->u.dst.xfrm);
289
290                 __in6_dev_put(loopback_idev);
291         }
292
293         xfrm_dst_ifdown(dst, dev);
294 }
295
296 static struct dst_ops xfrm6_dst_ops = {
297         .family =               AF_INET6,
298         .protocol =             __constant_htons(ETH_P_IPV6),
299         .gc =                   xfrm6_garbage_collect,
300         .update_pmtu =          xfrm6_update_pmtu,
301         .destroy =              xfrm6_dst_destroy,
302         .ifdown =               xfrm6_dst_ifdown,
303         .gc_thresh =            1024,
304         .entry_size =           sizeof(struct xfrm_dst),
305 };
306
307 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
308         .family =               AF_INET6,
309         .dst_ops =              &xfrm6_dst_ops,
310         .dst_lookup =           xfrm6_dst_lookup,
311         .find_bundle =          __xfrm6_find_bundle,
312         .bundle_create =        __xfrm6_bundle_create,
313         .decode_session =       _decode_session6,
314 };
315
316 static void __init xfrm6_policy_init(void)
317 {
318         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
319 }
320
321 static void xfrm6_policy_fini(void)
322 {
323         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
324 }
325
326 void __init xfrm6_init(void)
327 {
328         xfrm6_policy_init();
329         xfrm6_state_init();
330 }
331
332 void xfrm6_fini(void)
333 {
334         //xfrm6_input_fini();
335         xfrm6_policy_fini();
336         xfrm6_state_fini();
337 }