6baeabbbca82416ffb940be126de520a847779a9
[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                                           xfrm_address_t *saddr,
31                                           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(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                           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         /* Sheit... I remember I did this right. Apparently,
102          * it was magically lost, so this code needs audit */
103         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
104                                                    RTF_LOCAL);
105         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
106         xdst->u.rt6.rt6i_node = rt->rt6i_node;
107         if (rt->rt6i_node)
108                 xdst->route_cookie = rt->rt6i_node->fn_sernum;
109         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
110         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
111         xdst->u.rt6.rt6i_src = rt->rt6i_src;
112
113         return 0;
114 }
115
116 static inline void
117 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
118 {
119         int onlyproto = 0;
120         u16 offset = skb_network_header_len(skb);
121         struct ipv6hdr *hdr = ipv6_hdr(skb);
122         struct ipv6_opt_hdr *exthdr;
123         const unsigned char *nh = skb_network_header(skb);
124         u8 nexthdr = nh[IP6CB(skb)->nhoff];
125
126         memset(fl, 0, sizeof(struct flowi));
127         fl->mark = skb->mark;
128
129         ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
130         ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
131
132         while (nh + offset + 1 < skb->data ||
133                pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
134                 nh = skb_network_header(skb);
135                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
136
137                 switch (nexthdr) {
138                 case NEXTHDR_FRAGMENT:
139                         onlyproto = 1;
140                 case NEXTHDR_ROUTING:
141                 case NEXTHDR_HOP:
142                 case NEXTHDR_DEST:
143                         offset += ipv6_optlen(exthdr);
144                         nexthdr = exthdr->nexthdr;
145                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
146                         break;
147
148                 case IPPROTO_UDP:
149                 case IPPROTO_UDPLITE:
150                 case IPPROTO_TCP:
151                 case IPPROTO_SCTP:
152                 case IPPROTO_DCCP:
153                         if (!onlyproto && (nh + offset + 4 < skb->data ||
154                              pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
155                                 __be16 *ports = (__be16 *)exthdr;
156
157                                 fl->fl_ip_sport = ports[!!reverse];
158                                 fl->fl_ip_dport = ports[!reverse];
159                         }
160                         fl->proto = nexthdr;
161                         return;
162
163                 case IPPROTO_ICMPV6:
164                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
165                                 u8 *icmp = (u8 *)exthdr;
166
167                                 fl->fl_icmp_type = icmp[0];
168                                 fl->fl_icmp_code = icmp[1];
169                         }
170                         fl->proto = nexthdr;
171                         return;
172
173 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
174                 case IPPROTO_MH:
175                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
176                                 struct ip6_mh *mh;
177                                 mh = (struct ip6_mh *)exthdr;
178
179                                 fl->fl_mh_type = mh->ip6mh_type;
180                         }
181                         fl->proto = nexthdr;
182                         return;
183 #endif
184
185                 /* XXX Why are there these headers? */
186                 case IPPROTO_AH:
187                 case IPPROTO_ESP:
188                 case IPPROTO_COMP:
189                 default:
190                         fl->fl_ipsec_spi = 0;
191                         fl->proto = nexthdr;
192                         return;
193                 }
194         }
195 }
196
197 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
198 {
199         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
200
201         xfrm6_policy_afinfo.garbage_collect(net);
202         return (atomic_read(&ops->entries) > ops->gc_thresh * 2);
203 }
204
205 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
206 {
207         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
208         struct dst_entry *path = xdst->route;
209
210         path->ops->update_pmtu(path, mtu);
211 }
212
213 static void xfrm6_dst_destroy(struct dst_entry *dst)
214 {
215         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
216
217         if (likely(xdst->u.rt6.rt6i_idev))
218                 in6_dev_put(xdst->u.rt6.rt6i_idev);
219         xfrm_dst_destroy(xdst);
220 }
221
222 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
223                              int unregister)
224 {
225         struct xfrm_dst *xdst;
226
227         if (!unregister)
228                 return;
229
230         xdst = (struct xfrm_dst *)dst;
231         if (xdst->u.rt6.rt6i_idev->dev == dev) {
232                 struct inet6_dev *loopback_idev =
233                         in6_dev_get(dev_net(dev)->loopback_dev);
234                 BUG_ON(!loopback_idev);
235
236                 do {
237                         in6_dev_put(xdst->u.rt6.rt6i_idev);
238                         xdst->u.rt6.rt6i_idev = loopback_idev;
239                         in6_dev_hold(loopback_idev);
240                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
241                 } while (xdst->u.dst.xfrm);
242
243                 __in6_dev_put(loopback_idev);
244         }
245
246         xfrm_dst_ifdown(dst, dev);
247 }
248
249 static struct dst_ops xfrm6_dst_ops = {
250         .family =               AF_INET6,
251         .protocol =             cpu_to_be16(ETH_P_IPV6),
252         .gc =                   xfrm6_garbage_collect,
253         .update_pmtu =          xfrm6_update_pmtu,
254         .destroy =              xfrm6_dst_destroy,
255         .ifdown =               xfrm6_dst_ifdown,
256         .local_out =            __ip6_local_out,
257         .gc_thresh =            1024,
258         .entries =              ATOMIC_INIT(0),
259 };
260
261 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
262         .family =               AF_INET6,
263         .dst_ops =              &xfrm6_dst_ops,
264         .dst_lookup =           xfrm6_dst_lookup,
265         .get_saddr =            xfrm6_get_saddr,
266         .decode_session =       _decode_session6,
267         .get_tos =              xfrm6_get_tos,
268         .init_path =            xfrm6_init_path,
269         .fill_dst =             xfrm6_fill_dst,
270 };
271
272 static int __init xfrm6_policy_init(void)
273 {
274         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
275 }
276
277 static void xfrm6_policy_fini(void)
278 {
279         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
280 }
281
282 #ifdef CONFIG_SYSCTL
283 static struct ctl_table xfrm6_policy_table[] = {
284         {
285                 .procname       = "xfrm6_gc_thresh",
286                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
287                 .maxlen         = sizeof(int),
288                 .mode           = 0644,
289                 .proc_handler   = proc_dointvec,
290         },
291         { }
292 };
293
294 static struct ctl_table_header *sysctl_hdr;
295 #endif
296
297 int __init xfrm6_init(void)
298 {
299         int ret;
300         unsigned int gc_thresh;
301
302         /*
303          * We need a good default value for the xfrm6 gc threshold.
304          * In ipv4 we set it to the route hash table size * 8, which
305          * is half the size of the maximaum route cache for ipv4.  It
306          * would be good to do the same thing for v6, except the table is
307          * constructed differently here.  Here each table for a net namespace
308          * can have FIB_TABLE_HASHSZ entries, so lets go with the same
309          * computation that we used for ipv4 here.  Also, lets keep the initial
310          * gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
311          * to that as a minimum as well
312          */
313         gc_thresh = FIB6_TABLE_HASHSZ * 8;
314         xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
315
316         ret = xfrm6_policy_init();
317         if (ret)
318                 goto out;
319
320         ret = xfrm6_state_init();
321         if (ret)
322                 goto out_policy;
323
324 #ifdef CONFIG_SYSCTL
325         sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv6_ctl_path,
326                                                 xfrm6_policy_table);
327 #endif
328 out:
329         return ret;
330 out_policy:
331         xfrm6_policy_fini();
332         goto out;
333 }
334
335 void xfrm6_fini(void)
336 {
337 #ifdef CONFIG_SYSCTL
338         if (sysctl_hdr)
339                 unregister_net_sysctl_table(sysctl_hdr);
340 #endif
341         //xfrm6_input_fini();
342         xfrm6_policy_fini();
343         xfrm6_state_fini();
344 }