f3ed8ca59b942497ba0193268fed95801c364d7a
[sfrench/cifs-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 IS_ENABLED(CONFIG_IPV6_MIP6)
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 void xfrm6_init_dst(struct net *net, struct xfrm_dst *xdst)
77 {
78         struct rt6_info *rt = (struct rt6_info *)xdst;
79
80         rt6_init_peer(rt, net->ipv6.peers);
81 }
82
83 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
84                            int nfheader_len)
85 {
86         if (dst->ops->family == AF_INET6) {
87                 struct rt6_info *rt = (struct rt6_info*)dst;
88                 if (rt->rt6i_node)
89                         path->path_cookie = rt->rt6i_node->fn_sernum;
90         }
91
92         path->u.rt6.rt6i_nfheader_len = nfheader_len;
93
94         return 0;
95 }
96
97 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
98                           const struct flowi *fl)
99 {
100         struct rt6_info *rt = (struct rt6_info*)xdst->route;
101
102         xdst->u.dst.dev = dev;
103         dev_hold(dev);
104
105         xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
106         if (!xdst->u.rt6.rt6i_idev)
107                 return -ENODEV;
108
109         rt6_transfer_peer(&xdst->u.rt6, rt);
110
111         /* Sheit... I remember I did this right. Apparently,
112          * it was magically lost, so this code needs audit */
113         xdst->u.rt6.n = neigh_clone(rt->n);
114         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
115                                                    RTF_LOCAL);
116         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
117         xdst->u.rt6.rt6i_node = rt->rt6i_node;
118         if (rt->rt6i_node)
119                 xdst->route_cookie = rt->rt6i_node->fn_sernum;
120         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
121         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
122         xdst->u.rt6.rt6i_src = rt->rt6i_src;
123
124         return 0;
125 }
126
127 static inline void
128 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
129 {
130         struct flowi6 *fl6 = &fl->u.ip6;
131         int onlyproto = 0;
132         u16 offset = skb_network_header_len(skb);
133         const struct ipv6hdr *hdr = ipv6_hdr(skb);
134         struct ipv6_opt_hdr *exthdr;
135         const unsigned char *nh = skb_network_header(skb);
136         u8 nexthdr = nh[IP6CB(skb)->nhoff];
137
138         memset(fl6, 0, sizeof(struct flowi6));
139         fl6->flowi6_mark = skb->mark;
140
141         fl6->daddr = reverse ? hdr->saddr : hdr->daddr;
142         fl6->saddr = reverse ? hdr->daddr : hdr->saddr;
143
144         while (nh + offset + 1 < skb->data ||
145                pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
146                 nh = skb_network_header(skb);
147                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
148
149                 switch (nexthdr) {
150                 case NEXTHDR_FRAGMENT:
151                         onlyproto = 1;
152                 case NEXTHDR_ROUTING:
153                 case NEXTHDR_HOP:
154                 case NEXTHDR_DEST:
155                         offset += ipv6_optlen(exthdr);
156                         nexthdr = exthdr->nexthdr;
157                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
158                         break;
159
160                 case IPPROTO_UDP:
161                 case IPPROTO_UDPLITE:
162                 case IPPROTO_TCP:
163                 case IPPROTO_SCTP:
164                 case IPPROTO_DCCP:
165                         if (!onlyproto && (nh + offset + 4 < skb->data ||
166                              pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
167                                 __be16 *ports = (__be16 *)exthdr;
168
169                                 fl6->fl6_sport = ports[!!reverse];
170                                 fl6->fl6_dport = ports[!reverse];
171                         }
172                         fl6->flowi6_proto = nexthdr;
173                         return;
174
175                 case IPPROTO_ICMPV6:
176                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
177                                 u8 *icmp = (u8 *)exthdr;
178
179                                 fl6->fl6_icmp_type = icmp[0];
180                                 fl6->fl6_icmp_code = icmp[1];
181                         }
182                         fl6->flowi6_proto = nexthdr;
183                         return;
184
185 #if IS_ENABLED(CONFIG_IPV6_MIP6)
186                 case IPPROTO_MH:
187                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
188                                 struct ip6_mh *mh;
189                                 mh = (struct ip6_mh *)exthdr;
190
191                                 fl6->fl6_mh_type = mh->ip6mh_type;
192                         }
193                         fl6->flowi6_proto = nexthdr;
194                         return;
195 #endif
196
197                 /* XXX Why are there these headers? */
198                 case IPPROTO_AH:
199                 case IPPROTO_ESP:
200                 case IPPROTO_COMP:
201                 default:
202                         fl6->fl6_ipsec_spi = 0;
203                         fl6->flowi6_proto = nexthdr;
204                         return;
205                 }
206         }
207 }
208
209 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
210 {
211         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
212
213         xfrm6_policy_afinfo.garbage_collect(net);
214         return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
215 }
216
217 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
218                               struct sk_buff *skb, u32 mtu)
219 {
220         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
221         struct dst_entry *path = xdst->route;
222
223         path->ops->update_pmtu(path, sk, skb, mtu);
224 }
225
226 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
227                            struct sk_buff *skb)
228 {
229         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
230         struct dst_entry *path = xdst->route;
231
232         path->ops->redirect(path, sk, skb);
233 }
234
235 static void xfrm6_dst_destroy(struct dst_entry *dst)
236 {
237         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
238
239         if (likely(xdst->u.rt6.rt6i_idev))
240                 in6_dev_put(xdst->u.rt6.rt6i_idev);
241         dst_destroy_metrics_generic(dst);
242         if (rt6_has_peer(&xdst->u.rt6)) {
243                 struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6);
244                 inet_putpeer(peer);
245         }
246         xfrm_dst_destroy(xdst);
247 }
248
249 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
250                              int unregister)
251 {
252         struct xfrm_dst *xdst;
253
254         if (!unregister)
255                 return;
256
257         xdst = (struct xfrm_dst *)dst;
258         if (xdst->u.rt6.rt6i_idev->dev == dev) {
259                 struct inet6_dev *loopback_idev =
260                         in6_dev_get(dev_net(dev)->loopback_dev);
261                 BUG_ON(!loopback_idev);
262
263                 do {
264                         in6_dev_put(xdst->u.rt6.rt6i_idev);
265                         xdst->u.rt6.rt6i_idev = loopback_idev;
266                         in6_dev_hold(loopback_idev);
267                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
268                 } while (xdst->u.dst.xfrm);
269
270                 __in6_dev_put(loopback_idev);
271         }
272
273         xfrm_dst_ifdown(dst, dev);
274 }
275
276 static struct dst_ops xfrm6_dst_ops = {
277         .family =               AF_INET6,
278         .protocol =             cpu_to_be16(ETH_P_IPV6),
279         .gc =                   xfrm6_garbage_collect,
280         .update_pmtu =          xfrm6_update_pmtu,
281         .redirect =             xfrm6_redirect,
282         .cow_metrics =          dst_cow_metrics_generic,
283         .destroy =              xfrm6_dst_destroy,
284         .ifdown =               xfrm6_dst_ifdown,
285         .local_out =            __ip6_local_out,
286         .gc_thresh =            1024,
287 };
288
289 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
290         .family =               AF_INET6,
291         .dst_ops =              &xfrm6_dst_ops,
292         .dst_lookup =           xfrm6_dst_lookup,
293         .get_saddr =            xfrm6_get_saddr,
294         .decode_session =       _decode_session6,
295         .get_tos =              xfrm6_get_tos,
296         .init_dst =             xfrm6_init_dst,
297         .init_path =            xfrm6_init_path,
298         .fill_dst =             xfrm6_fill_dst,
299         .blackhole_route =      ip6_blackhole_route,
300 };
301
302 static int __init xfrm6_policy_init(void)
303 {
304         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
305 }
306
307 static void xfrm6_policy_fini(void)
308 {
309         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
310 }
311
312 #ifdef CONFIG_SYSCTL
313 static struct ctl_table xfrm6_policy_table[] = {
314         {
315                 .procname       = "xfrm6_gc_thresh",
316                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
317                 .maxlen         = sizeof(int),
318                 .mode           = 0644,
319                 .proc_handler   = proc_dointvec,
320         },
321         { }
322 };
323
324 static struct ctl_table_header *sysctl_hdr;
325 #endif
326
327 int __init xfrm6_init(void)
328 {
329         int ret;
330         unsigned int gc_thresh;
331
332         /*
333          * We need a good default value for the xfrm6 gc threshold.
334          * In ipv4 we set it to the route hash table size * 8, which
335          * is half the size of the maximaum route cache for ipv4.  It
336          * would be good to do the same thing for v6, except the table is
337          * constructed differently here.  Here each table for a net namespace
338          * can have FIB_TABLE_HASHSZ entries, so lets go with the same
339          * computation that we used for ipv4 here.  Also, lets keep the initial
340          * gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
341          * to that as a minimum as well
342          */
343         gc_thresh = FIB6_TABLE_HASHSZ * 8;
344         xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
345         dst_entries_init(&xfrm6_dst_ops);
346
347         ret = xfrm6_policy_init();
348         if (ret) {
349                 dst_entries_destroy(&xfrm6_dst_ops);
350                 goto out;
351         }
352         ret = xfrm6_state_init();
353         if (ret)
354                 goto out_policy;
355
356 #ifdef CONFIG_SYSCTL
357         sysctl_hdr = register_net_sysctl(&init_net, "net/ipv6",
358                                          xfrm6_policy_table);
359 #endif
360 out:
361         return ret;
362 out_policy:
363         xfrm6_policy_fini();
364         goto out;
365 }
366
367 void xfrm6_fini(void)
368 {
369 #ifdef CONFIG_SYSCTL
370         if (sysctl_hdr)
371                 unregister_net_sysctl_table(sysctl_hdr);
372 #endif
373         //xfrm6_input_fini();
374         xfrm6_policy_fini();
375         xfrm6_state_fini();
376         dst_entries_destroy(&xfrm6_dst_ops);
377 }