From: Kazunori Miyazawa <kazunori@miyazawa.org>
[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                 if (rt->rt6i_node)
117                         xdst->route_cookie = rt->rt6i_node->fn_sernum;
118
119                 dst1->next = dst_prev;
120                 dst_prev = dst1;
121                 if (xfrm[i]->props.mode) {
122                         remote = (struct in6_addr*)&xfrm[i]->id.daddr;
123                         local  = (struct in6_addr*)&xfrm[i]->props.saddr;
124                         tunnel = 1;
125                 }
126                 header_len += xfrm[i]->props.header_len;
127                 trailer_len += xfrm[i]->props.trailer_len;
128
129                 if (tunnel) {
130                         ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
131                         ipv6_addr_copy(&fl_tunnel.fl6_src, local);
132                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
133                                               &fl_tunnel, AF_INET6);
134                         if (err)
135                                 goto error;
136                 } else
137                         dst_hold(&rt->u.dst);
138         }
139
140         dst_prev->child = &rt->u.dst;
141         dst->path = &rt->u.dst;
142         if (rt->rt6i_node)
143                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
144
145         *dst_p = dst;
146         dst = dst_prev;
147
148         dst_prev = *dst_p;
149         i = 0;
150         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
151                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
152
153                 dst_prev->xfrm = xfrm[i++];
154                 dst_prev->dev = rt->u.dst.dev;
155                 if (rt->u.dst.dev)
156                         dev_hold(rt->u.dst.dev);
157                 dst_prev->obsolete      = -1;
158                 dst_prev->flags        |= DST_HOST;
159                 dst_prev->lastuse       = jiffies;
160                 dst_prev->header_len    = header_len;
161                 dst_prev->trailer_len   = trailer_len;
162                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
163
164                 /* Copy neighbour for reachability confirmation */
165                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
166                 dst_prev->input         = rt->u.dst.input;
167                 dst_prev->output        = xfrm6_output;
168                 /* Sheit... I remember I did this right. Apparently,
169                  * it was magically lost, so this code needs audit */
170                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
171                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
172                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
173                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
174                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway)); 
175                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
176                 x->u.rt6.rt6i_src      = rt0->rt6i_src; 
177                 x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
178                 in6_dev_hold(rt0->rt6i_idev);
179                 header_len -= x->u.dst.xfrm->props.header_len;
180                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
181         }
182
183         xfrm_init_pmtu(dst);
184         return 0;
185
186 error:
187         if (dst)
188                 dst_free(dst);
189         return err;
190 }
191
192 static inline void
193 _decode_session6(struct sk_buff *skb, struct flowi *fl)
194 {
195         u16 offset = sizeof(struct ipv6hdr);
196         struct ipv6hdr *hdr = skb->nh.ipv6h;
197         struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
198         u8 nexthdr = skb->nh.ipv6h->nexthdr;
199
200         memset(fl, 0, sizeof(struct flowi));
201         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
202         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
203
204         while (pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data)) {
205                 switch (nexthdr) {
206                 case NEXTHDR_ROUTING:
207                 case NEXTHDR_HOP:
208                 case NEXTHDR_DEST:
209                         offset += ipv6_optlen(exthdr);
210                         nexthdr = exthdr->nexthdr;
211                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
212                         break;
213
214                 case IPPROTO_UDP:
215                 case IPPROTO_TCP:
216                 case IPPROTO_SCTP:
217                         if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
218                                 u16 *ports = (u16 *)exthdr;
219
220                                 fl->fl_ip_sport = ports[0];
221                                 fl->fl_ip_dport = ports[1];
222                         }
223                         fl->proto = nexthdr;
224                         return;
225
226                 case IPPROTO_ICMPV6:
227                         if (pskb_may_pull(skb, skb->nh.raw + offset + 2 - skb->data)) {
228                                 u8 *icmp = (u8 *)exthdr;
229
230                                 fl->fl_icmp_type = icmp[0];
231                                 fl->fl_icmp_code = icmp[1];
232                         }
233                         fl->proto = nexthdr;
234                         return;
235
236                 /* XXX Why are there these headers? */
237                 case IPPROTO_AH:
238                 case IPPROTO_ESP:
239                 case IPPROTO_COMP:
240                 default:
241                         fl->fl_ipsec_spi = 0;
242                         fl->proto = nexthdr;
243                         return;
244                 };
245         }
246 }
247
248 static inline int xfrm6_garbage_collect(void)
249 {
250         read_lock(&xfrm6_policy_afinfo.lock);
251         xfrm6_policy_afinfo.garbage_collect();
252         read_unlock(&xfrm6_policy_afinfo.lock);
253         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
254 }
255
256 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
257 {
258         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
259         struct dst_entry *path = xdst->route;
260
261         path->ops->update_pmtu(path, mtu);
262 }
263
264 static void xfrm6_dst_destroy(struct dst_entry *dst)
265 {
266         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
267
268         if (likely(xdst->u.rt6.rt6i_idev))
269                 in6_dev_put(xdst->u.rt6.rt6i_idev);
270         xfrm_dst_destroy(xdst);
271 }
272
273 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
274                              int unregister)
275 {
276         struct xfrm_dst *xdst;
277
278         if (!unregister)
279                 return;
280
281         xdst = (struct xfrm_dst *)dst;
282         if (xdst->u.rt6.rt6i_idev->dev == dev) {
283                 struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
284                 BUG_ON(!loopback_idev);
285
286                 do {
287                         in6_dev_put(xdst->u.rt6.rt6i_idev);
288                         xdst->u.rt6.rt6i_idev = loopback_idev;
289                         in6_dev_hold(loopback_idev);
290                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
291                 } while (xdst->u.dst.xfrm);
292
293                 __in6_dev_put(loopback_idev);
294         }
295
296         xfrm_dst_ifdown(dst, dev);
297 }
298
299 static struct dst_ops xfrm6_dst_ops = {
300         .family =               AF_INET6,
301         .protocol =             __constant_htons(ETH_P_IPV6),
302         .gc =                   xfrm6_garbage_collect,
303         .update_pmtu =          xfrm6_update_pmtu,
304         .destroy =              xfrm6_dst_destroy,
305         .ifdown =               xfrm6_dst_ifdown,
306         .gc_thresh =            1024,
307         .entry_size =           sizeof(struct xfrm_dst),
308 };
309
310 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
311         .family =               AF_INET6,
312         .lock =                 RW_LOCK_UNLOCKED,
313         .type_map =             &xfrm6_type_map,
314         .dst_ops =              &xfrm6_dst_ops,
315         .dst_lookup =           xfrm6_dst_lookup,
316         .find_bundle =          __xfrm6_find_bundle,
317         .bundle_create =        __xfrm6_bundle_create,
318         .decode_session =       _decode_session6,
319 };
320
321 static void __init xfrm6_policy_init(void)
322 {
323         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
324 }
325
326 static void xfrm6_policy_fini(void)
327 {
328         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
329 }
330
331 void __init xfrm6_init(void)
332 {
333         xfrm6_policy_init();
334         xfrm6_state_init();
335 }
336
337 void xfrm6_fini(void)
338 {
339         //xfrm6_input_fini();
340         xfrm6_policy_fini();
341         xfrm6_state_fini();
342 }