ipv4: fix redirect handling
[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/err.h>
15 #include <linux/kernel.h>
16 #include <linux/netdevice.h>
17 #include <net/addrconf.h>
18 #include <net/dst.h>
19 #include <net/xfrm.h>
20 #include <net/ip.h>
21 #include <net/ipv6.h>
22 #include <net/ip6_route.h>
23 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
24 #include <net/mip6.h>
25 #endif
26
27 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
28
29 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos,
30                                           const xfrm_address_t *saddr,
31                                           const xfrm_address_t *daddr)
32 {
33         struct flowi6 fl6;
34         struct dst_entry *dst;
35         int err;
36
37         memset(&fl6, 0, sizeof(fl6));
38         memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr));
39         if (saddr)
40                 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr));
41
42         dst = ip6_route_output(net, NULL, &fl6);
43
44         err = dst->error;
45         if (dst->error) {
46                 dst_release(dst);
47                 dst = ERR_PTR(err);
48         }
49
50         return dst;
51 }
52
53 static int xfrm6_get_saddr(struct net *net,
54                            xfrm_address_t *saddr, xfrm_address_t *daddr)
55 {
56         struct dst_entry *dst;
57         struct net_device *dev;
58
59         dst = xfrm6_dst_lookup(net, 0, NULL, daddr);
60         if (IS_ERR(dst))
61                 return -EHOSTUNREACH;
62
63         dev = ip6_dst_idev(dst)->dev;
64         ipv6_dev_get_saddr(dev_net(dev), dev,
65                            (struct in6_addr *)&daddr->a6, 0,
66                            (struct in6_addr *)&saddr->a6);
67         dst_release(dst);
68         return 0;
69 }
70
71 static int xfrm6_get_tos(const struct flowi *fl)
72 {
73         return 0;
74 }
75
76 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
77                            int nfheader_len)
78 {
79         if (dst->ops->family == AF_INET6) {
80                 struct rt6_info *rt = (struct rt6_info*)dst;
81                 if (rt->rt6i_node)
82                         path->path_cookie = rt->rt6i_node->fn_sernum;
83         }
84
85         path->u.rt6.rt6i_nfheader_len = nfheader_len;
86
87         return 0;
88 }
89
90 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
91                           const struct flowi *fl)
92 {
93         struct rt6_info *rt = (struct rt6_info*)xdst->route;
94
95         xdst->u.dst.dev = dev;
96         dev_hold(dev);
97
98         xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
99         if (!xdst->u.rt6.rt6i_idev)
100                 return -ENODEV;
101
102         xdst->u.rt6.rt6i_peer = rt->rt6i_peer;
103         if (rt->rt6i_peer)
104                 atomic_inc(&rt->rt6i_peer->refcnt);
105
106         /* Sheit... I remember I did this right. Apparently,
107          * it was magically lost, so this code needs audit */
108         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
109                                                    RTF_LOCAL);
110         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
111         xdst->u.rt6.rt6i_node = rt->rt6i_node;
112         if (rt->rt6i_node)
113                 xdst->route_cookie = rt->rt6i_node->fn_sernum;
114         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
115         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
116         xdst->u.rt6.rt6i_src = rt->rt6i_src;
117
118         return 0;
119 }
120
121 static inline void
122 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
123 {
124         struct flowi6 *fl6 = &fl->u.ip6;
125         int onlyproto = 0;
126         u16 offset = skb_network_header_len(skb);
127         const struct ipv6hdr *hdr = ipv6_hdr(skb);
128         struct ipv6_opt_hdr *exthdr;
129         const unsigned char *nh = skb_network_header(skb);
130         u8 nexthdr = nh[IP6CB(skb)->nhoff];
131
132         memset(fl6, 0, sizeof(struct flowi6));
133         fl6->flowi6_mark = skb->mark;
134
135         ipv6_addr_copy(&fl6->daddr, reverse ? &hdr->saddr : &hdr->daddr);
136         ipv6_addr_copy(&fl6->saddr, reverse ? &hdr->daddr : &hdr->saddr);
137
138         while (nh + offset + 1 < skb->data ||
139                pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
140                 nh = skb_network_header(skb);
141                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
142
143                 switch (nexthdr) {
144                 case NEXTHDR_FRAGMENT:
145                         onlyproto = 1;
146                 case NEXTHDR_ROUTING:
147                 case NEXTHDR_HOP:
148                 case NEXTHDR_DEST:
149                         offset += ipv6_optlen(exthdr);
150                         nexthdr = exthdr->nexthdr;
151                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
152                         break;
153
154                 case IPPROTO_UDP:
155                 case IPPROTO_UDPLITE:
156                 case IPPROTO_TCP:
157                 case IPPROTO_SCTP:
158                 case IPPROTO_DCCP:
159                         if (!onlyproto && (nh + offset + 4 < skb->data ||
160                              pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
161                                 __be16 *ports = (__be16 *)exthdr;
162
163                                 fl6->fl6_sport = ports[!!reverse];
164                                 fl6->fl6_dport = ports[!reverse];
165                         }
166                         fl6->flowi6_proto = nexthdr;
167                         return;
168
169                 case IPPROTO_ICMPV6:
170                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
171                                 u8 *icmp = (u8 *)exthdr;
172
173                                 fl6->fl6_icmp_type = icmp[0];
174                                 fl6->fl6_icmp_code = icmp[1];
175                         }
176                         fl6->flowi6_proto = nexthdr;
177                         return;
178
179 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
180                 case IPPROTO_MH:
181                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
182                                 struct ip6_mh *mh;
183                                 mh = (struct ip6_mh *)exthdr;
184
185                                 fl6->fl6_mh_type = mh->ip6mh_type;
186                         }
187                         fl6->flowi6_proto = nexthdr;
188                         return;
189 #endif
190
191                 /* XXX Why are there these headers? */
192                 case IPPROTO_AH:
193                 case IPPROTO_ESP:
194                 case IPPROTO_COMP:
195                 default:
196                         fl6->fl6_ipsec_spi = 0;
197                         fl6->flowi6_proto = nexthdr;
198                         return;
199                 }
200         }
201 }
202
203 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
204 {
205         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
206
207         xfrm6_policy_afinfo.garbage_collect(net);
208         return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
209 }
210
211 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
212 {
213         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
214         struct dst_entry *path = xdst->route;
215
216         path->ops->update_pmtu(path, mtu);
217 }
218
219 static void xfrm6_dst_destroy(struct dst_entry *dst)
220 {
221         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
222
223         if (likely(xdst->u.rt6.rt6i_idev))
224                 in6_dev_put(xdst->u.rt6.rt6i_idev);
225         dst_destroy_metrics_generic(dst);
226         if (likely(xdst->u.rt6.rt6i_peer))
227                 inet_putpeer(xdst->u.rt6.rt6i_peer);
228         xfrm_dst_destroy(xdst);
229 }
230
231 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
232                              int unregister)
233 {
234         struct xfrm_dst *xdst;
235
236         if (!unregister)
237                 return;
238
239         xdst = (struct xfrm_dst *)dst;
240         if (xdst->u.rt6.rt6i_idev->dev == dev) {
241                 struct inet6_dev *loopback_idev =
242                         in6_dev_get(dev_net(dev)->loopback_dev);
243                 BUG_ON(!loopback_idev);
244
245                 do {
246                         in6_dev_put(xdst->u.rt6.rt6i_idev);
247                         xdst->u.rt6.rt6i_idev = loopback_idev;
248                         in6_dev_hold(loopback_idev);
249                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
250                 } while (xdst->u.dst.xfrm);
251
252                 __in6_dev_put(loopback_idev);
253         }
254
255         xfrm_dst_ifdown(dst, dev);
256 }
257
258 static struct dst_ops xfrm6_dst_ops = {
259         .family =               AF_INET6,
260         .protocol =             cpu_to_be16(ETH_P_IPV6),
261         .gc =                   xfrm6_garbage_collect,
262         .update_pmtu =          xfrm6_update_pmtu,
263         .cow_metrics =          dst_cow_metrics_generic,
264         .destroy =              xfrm6_dst_destroy,
265         .ifdown =               xfrm6_dst_ifdown,
266         .local_out =            __ip6_local_out,
267         .gc_thresh =            1024,
268 };
269
270 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
271         .family =               AF_INET6,
272         .dst_ops =              &xfrm6_dst_ops,
273         .dst_lookup =           xfrm6_dst_lookup,
274         .get_saddr =            xfrm6_get_saddr,
275         .decode_session =       _decode_session6,
276         .get_tos =              xfrm6_get_tos,
277         .init_path =            xfrm6_init_path,
278         .fill_dst =             xfrm6_fill_dst,
279         .blackhole_route =      ip6_blackhole_route,
280 };
281
282 static int __init xfrm6_policy_init(void)
283 {
284         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
285 }
286
287 static void xfrm6_policy_fini(void)
288 {
289         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
290 }
291
292 #ifdef CONFIG_SYSCTL
293 static struct ctl_table xfrm6_policy_table[] = {
294         {
295                 .procname       = "xfrm6_gc_thresh",
296                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
297                 .maxlen         = sizeof(int),
298                 .mode           = 0644,
299                 .proc_handler   = proc_dointvec,
300         },
301         { }
302 };
303
304 static struct ctl_table_header *sysctl_hdr;
305 #endif
306
307 int __init xfrm6_init(void)
308 {
309         int ret;
310         unsigned int gc_thresh;
311
312         /*
313          * We need a good default value for the xfrm6 gc threshold.
314          * In ipv4 we set it to the route hash table size * 8, which
315          * is half the size of the maximaum route cache for ipv4.  It
316          * would be good to do the same thing for v6, except the table is
317          * constructed differently here.  Here each table for a net namespace
318          * can have FIB_TABLE_HASHSZ entries, so lets go with the same
319          * computation that we used for ipv4 here.  Also, lets keep the initial
320          * gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
321          * to that as a minimum as well
322          */
323         gc_thresh = FIB6_TABLE_HASHSZ * 8;
324         xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
325         dst_entries_init(&xfrm6_dst_ops);
326
327         ret = xfrm6_policy_init();
328         if (ret) {
329                 dst_entries_destroy(&xfrm6_dst_ops);
330                 goto out;
331         }
332         ret = xfrm6_state_init();
333         if (ret)
334                 goto out_policy;
335
336 #ifdef CONFIG_SYSCTL
337         sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv6_ctl_path,
338                                                 xfrm6_policy_table);
339 #endif
340 out:
341         return ret;
342 out_policy:
343         xfrm6_policy_fini();
344         goto out;
345 }
346
347 void xfrm6_fini(void)
348 {
349 #ifdef CONFIG_SYSCTL
350         if (sysctl_hdr)
351                 unregister_net_sysctl_table(sysctl_hdr);
352 #endif
353         //xfrm6_input_fini();
354         xfrm6_policy_fini();
355         xfrm6_state_fini();
356         dst_entries_destroy(&xfrm6_dst_ops);
357 }