d62496c1a6f941f7b1b9445e01d37e3521340975
[linux-3.10.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 flowi fl = {};
34         struct dst_entry *dst;
35         int err;
36
37         memcpy(&fl.fl6_dst, daddr, sizeof(fl.fl6_dst));
38         if (saddr)
39                 memcpy(&fl.fl6_src, saddr, sizeof(fl.fl6_src));
40
41         dst = ip6_route_output(net, NULL, &fl);
42
43         err = dst->error;
44         if (dst->error) {
45                 dst_release(dst);
46                 dst = ERR_PTR(err);
47         }
48
49         return dst;
50 }
51
52 static int xfrm6_get_saddr(struct net *net,
53                            xfrm_address_t *saddr, xfrm_address_t *daddr)
54 {
55         struct dst_entry *dst;
56         struct net_device *dev;
57
58         dst = xfrm6_dst_lookup(net, 0, NULL, daddr);
59         if (IS_ERR(dst))
60                 return -EHOSTUNREACH;
61
62         dev = ip6_dst_idev(dst)->dev;
63         ipv6_dev_get_saddr(dev_net(dev), dev,
64                            (struct in6_addr *)&daddr->a6, 0,
65                            (struct in6_addr *)&saddr->a6);
66         dst_release(dst);
67         return 0;
68 }
69
70 static int xfrm6_get_tos(const struct flowi *fl)
71 {
72         return 0;
73 }
74
75 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
76                            int nfheader_len)
77 {
78         if (dst->ops->family == AF_INET6) {
79                 struct rt6_info *rt = (struct rt6_info*)dst;
80                 if (rt->rt6i_node)
81                         path->path_cookie = rt->rt6i_node->fn_sernum;
82         }
83
84         path->u.rt6.rt6i_nfheader_len = nfheader_len;
85
86         return 0;
87 }
88
89 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
90                           const struct flowi *fl)
91 {
92         struct rt6_info *rt = (struct rt6_info*)xdst->route;
93
94         xdst->u.dst.dev = dev;
95         dev_hold(dev);
96
97         xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
98         if (!xdst->u.rt6.rt6i_idev)
99                 return -ENODEV;
100
101         xdst->u.rt6.rt6i_peer = rt->rt6i_peer;
102         if (rt->rt6i_peer)
103                 atomic_inc(&rt->rt6i_peer->refcnt);
104
105         /* Sheit... I remember I did this right. Apparently,
106          * it was magically lost, so this code needs audit */
107         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
108                                                    RTF_LOCAL);
109         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
110         xdst->u.rt6.rt6i_node = rt->rt6i_node;
111         if (rt->rt6i_node)
112                 xdst->route_cookie = rt->rt6i_node->fn_sernum;
113         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
114         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
115         xdst->u.rt6.rt6i_src = rt->rt6i_src;
116
117         return 0;
118 }
119
120 static inline void
121 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
122 {
123         int onlyproto = 0;
124         u16 offset = skb_network_header_len(skb);
125         struct ipv6hdr *hdr = ipv6_hdr(skb);
126         struct ipv6_opt_hdr *exthdr;
127         const unsigned char *nh = skb_network_header(skb);
128         u8 nexthdr = nh[IP6CB(skb)->nhoff];
129
130         memset(fl, 0, sizeof(struct flowi));
131         fl->flowi_mark = skb->mark;
132
133         ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
134         ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
135
136         while (nh + offset + 1 < skb->data ||
137                pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
138                 nh = skb_network_header(skb);
139                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
140
141                 switch (nexthdr) {
142                 case NEXTHDR_FRAGMENT:
143                         onlyproto = 1;
144                 case NEXTHDR_ROUTING:
145                 case NEXTHDR_HOP:
146                 case NEXTHDR_DEST:
147                         offset += ipv6_optlen(exthdr);
148                         nexthdr = exthdr->nexthdr;
149                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
150                         break;
151
152                 case IPPROTO_UDP:
153                 case IPPROTO_UDPLITE:
154                 case IPPROTO_TCP:
155                 case IPPROTO_SCTP:
156                 case IPPROTO_DCCP:
157                         if (!onlyproto && (nh + offset + 4 < skb->data ||
158                              pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
159                                 __be16 *ports = (__be16 *)exthdr;
160
161                                 fl->fl_ip_sport = ports[!!reverse];
162                                 fl->fl_ip_dport = ports[!reverse];
163                         }
164                         fl->flowi_proto = nexthdr;
165                         return;
166
167                 case IPPROTO_ICMPV6:
168                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
169                                 u8 *icmp = (u8 *)exthdr;
170
171                                 fl->fl_icmp_type = icmp[0];
172                                 fl->fl_icmp_code = icmp[1];
173                         }
174                         fl->flowi_proto = nexthdr;
175                         return;
176
177 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
178                 case IPPROTO_MH:
179                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
180                                 struct ip6_mh *mh;
181                                 mh = (struct ip6_mh *)exthdr;
182
183                                 fl->fl_mh_type = mh->ip6mh_type;
184                         }
185                         fl->flowi_proto = nexthdr;
186                         return;
187 #endif
188
189                 /* XXX Why are there these headers? */
190                 case IPPROTO_AH:
191                 case IPPROTO_ESP:
192                 case IPPROTO_COMP:
193                 default:
194                         fl->fl_ipsec_spi = 0;
195                         fl->flowi_proto = nexthdr;
196                         return;
197                 }
198         }
199 }
200
201 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
202 {
203         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
204
205         xfrm6_policy_afinfo.garbage_collect(net);
206         return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
207 }
208
209 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
210 {
211         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
212         struct dst_entry *path = xdst->route;
213
214         path->ops->update_pmtu(path, mtu);
215 }
216
217 static void xfrm6_dst_destroy(struct dst_entry *dst)
218 {
219         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
220
221         if (likely(xdst->u.rt6.rt6i_idev))
222                 in6_dev_put(xdst->u.rt6.rt6i_idev);
223         dst_destroy_metrics_generic(dst);
224         if (likely(xdst->u.rt6.rt6i_peer))
225                 inet_putpeer(xdst->u.rt6.rt6i_peer);
226         xfrm_dst_destroy(xdst);
227 }
228
229 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
230                              int unregister)
231 {
232         struct xfrm_dst *xdst;
233
234         if (!unregister)
235                 return;
236
237         xdst = (struct xfrm_dst *)dst;
238         if (xdst->u.rt6.rt6i_idev->dev == dev) {
239                 struct inet6_dev *loopback_idev =
240                         in6_dev_get(dev_net(dev)->loopback_dev);
241                 BUG_ON(!loopback_idev);
242
243                 do {
244                         in6_dev_put(xdst->u.rt6.rt6i_idev);
245                         xdst->u.rt6.rt6i_idev = loopback_idev;
246                         in6_dev_hold(loopback_idev);
247                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
248                 } while (xdst->u.dst.xfrm);
249
250                 __in6_dev_put(loopback_idev);
251         }
252
253         xfrm_dst_ifdown(dst, dev);
254 }
255
256 static struct dst_ops xfrm6_dst_ops = {
257         .family =               AF_INET6,
258         .protocol =             cpu_to_be16(ETH_P_IPV6),
259         .gc =                   xfrm6_garbage_collect,
260         .update_pmtu =          xfrm6_update_pmtu,
261         .cow_metrics =          dst_cow_metrics_generic,
262         .destroy =              xfrm6_dst_destroy,
263         .ifdown =               xfrm6_dst_ifdown,
264         .local_out =            __ip6_local_out,
265         .gc_thresh =            1024,
266 };
267
268 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
269         .family =               AF_INET6,
270         .dst_ops =              &xfrm6_dst_ops,
271         .dst_lookup =           xfrm6_dst_lookup,
272         .get_saddr =            xfrm6_get_saddr,
273         .decode_session =       _decode_session6,
274         .get_tos =              xfrm6_get_tos,
275         .init_path =            xfrm6_init_path,
276         .fill_dst =             xfrm6_fill_dst,
277         .blackhole_route =      ip6_blackhole_route,
278 };
279
280 static int __init xfrm6_policy_init(void)
281 {
282         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
283 }
284
285 static void xfrm6_policy_fini(void)
286 {
287         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
288 }
289
290 #ifdef CONFIG_SYSCTL
291 static struct ctl_table xfrm6_policy_table[] = {
292         {
293                 .procname       = "xfrm6_gc_thresh",
294                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
295                 .maxlen         = sizeof(int),
296                 .mode           = 0644,
297                 .proc_handler   = proc_dointvec,
298         },
299         { }
300 };
301
302 static struct ctl_table_header *sysctl_hdr;
303 #endif
304
305 int __init xfrm6_init(void)
306 {
307         int ret;
308         unsigned int gc_thresh;
309
310         /*
311          * We need a good default value for the xfrm6 gc threshold.
312          * In ipv4 we set it to the route hash table size * 8, which
313          * is half the size of the maximaum route cache for ipv4.  It
314          * would be good to do the same thing for v6, except the table is
315          * constructed differently here.  Here each table for a net namespace
316          * can have FIB_TABLE_HASHSZ entries, so lets go with the same
317          * computation that we used for ipv4 here.  Also, lets keep the initial
318          * gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
319          * to that as a minimum as well
320          */
321         gc_thresh = FIB6_TABLE_HASHSZ * 8;
322         xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
323         dst_entries_init(&xfrm6_dst_ops);
324
325         ret = xfrm6_policy_init();
326         if (ret) {
327                 dst_entries_destroy(&xfrm6_dst_ops);
328                 goto out;
329         }
330         ret = xfrm6_state_init();
331         if (ret)
332                 goto out_policy;
333
334 #ifdef CONFIG_SYSCTL
335         sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv6_ctl_path,
336                                                 xfrm6_policy_table);
337 #endif
338 out:
339         return ret;
340 out_policy:
341         xfrm6_policy_fini();
342         goto out;
343 }
344
345 void xfrm6_fini(void)
346 {
347 #ifdef CONFIG_SYSCTL
348         if (sysctl_hdr)
349                 unregister_net_sysctl_table(sysctl_hdr);
350 #endif
351         //xfrm6_input_fini();
352         xfrm6_policy_fini();
353         xfrm6_state_fini();
354         dst_entries_destroy(&xfrm6_dst_ops);
355 }