ah4/ah6: remove useless NULL assignments
[linux-2.6] / 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 dst_ops xfrm6_dst_ops;
28 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
29
30 static struct dst_entry *xfrm6_dst_lookup(int tos, 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(&init_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(xfrm_address_t *saddr, xfrm_address_t *daddr)
53 {
54         struct dst_entry *dst;
55         struct net_device *dev;
56
57         dst = xfrm6_dst_lookup(0, NULL, daddr);
58         if (IS_ERR(dst))
59                 return -EHOSTUNREACH;
60
61         dev = ip6_dst_idev(dst)->dev;
62         ipv6_dev_get_saddr(dev_net(dev), dev,
63                            (struct in6_addr *)&daddr->a6, 0,
64                            (struct in6_addr *)&saddr->a6);
65         dst_release(dst);
66         return 0;
67 }
68
69 static struct dst_entry *
70 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
71 {
72         struct dst_entry *dst;
73
74         /* Still not clear if we should set fl->fl6_{src,dst}... */
75         read_lock_bh(&policy->lock);
76         for (dst = policy->bundles; dst; dst = dst->next) {
77                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
78                 struct in6_addr fl_dst_prefix, fl_src_prefix;
79
80                 ipv6_addr_prefix(&fl_dst_prefix,
81                                  &fl->fl6_dst,
82                                  xdst->u.rt6.rt6i_dst.plen);
83                 ipv6_addr_prefix(&fl_src_prefix,
84                                  &fl->fl6_src,
85                                  xdst->u.rt6.rt6i_src.plen);
86                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
87                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
88                     xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
89                                    (xdst->u.rt6.rt6i_dst.plen != 128 ||
90                                     xdst->u.rt6.rt6i_src.plen != 128))) {
91                         dst_clone(dst);
92                         break;
93                 }
94         }
95         read_unlock_bh(&policy->lock);
96         return dst;
97 }
98
99 static int xfrm6_get_tos(struct flowi *fl)
100 {
101         return 0;
102 }
103
104 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
105                            int nfheader_len)
106 {
107         if (dst->ops->family == AF_INET6) {
108                 struct rt6_info *rt = (struct rt6_info*)dst;
109                 if (rt->rt6i_node)
110                         path->path_cookie = rt->rt6i_node->fn_sernum;
111         }
112
113         path->u.rt6.rt6i_nfheader_len = nfheader_len;
114
115         return 0;
116 }
117
118 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
119 {
120         struct rt6_info *rt = (struct rt6_info*)xdst->route;
121
122         xdst->u.dst.dev = dev;
123         dev_hold(dev);
124
125         xdst->u.rt6.rt6i_idev = in6_dev_get(rt->u.dst.dev);
126         if (!xdst->u.rt6.rt6i_idev)
127                 return -ENODEV;
128
129         /* Sheit... I remember I did this right. Apparently,
130          * it was magically lost, so this code needs audit */
131         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
132                                                    RTF_LOCAL);
133         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
134         xdst->u.rt6.rt6i_node = rt->rt6i_node;
135         if (rt->rt6i_node)
136                 xdst->route_cookie = rt->rt6i_node->fn_sernum;
137         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
138         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
139         xdst->u.rt6.rt6i_src = rt->rt6i_src;
140
141         return 0;
142 }
143
144 static inline void
145 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
146 {
147         int onlyproto = 0;
148         u16 offset = skb_network_header_len(skb);
149         struct ipv6hdr *hdr = ipv6_hdr(skb);
150         struct ipv6_opt_hdr *exthdr;
151         const unsigned char *nh = skb_network_header(skb);
152         u8 nexthdr = nh[IP6CB(skb)->nhoff];
153
154         memset(fl, 0, sizeof(struct flowi));
155         ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
156         ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
157
158         while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
159                 nh = skb_network_header(skb);
160                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
161
162                 switch (nexthdr) {
163                 case NEXTHDR_FRAGMENT:
164                         onlyproto = 1;
165                 case NEXTHDR_ROUTING:
166                 case NEXTHDR_HOP:
167                 case NEXTHDR_DEST:
168                         offset += ipv6_optlen(exthdr);
169                         nexthdr = exthdr->nexthdr;
170                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
171                         break;
172
173                 case IPPROTO_UDP:
174                 case IPPROTO_UDPLITE:
175                 case IPPROTO_TCP:
176                 case IPPROTO_SCTP:
177                 case IPPROTO_DCCP:
178                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
179                                 __be16 *ports = (__be16 *)exthdr;
180
181                                 fl->fl_ip_sport = ports[!!reverse];
182                                 fl->fl_ip_dport = ports[!reverse];
183                         }
184                         fl->proto = nexthdr;
185                         return;
186
187                 case IPPROTO_ICMPV6:
188                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
189                                 u8 *icmp = (u8 *)exthdr;
190
191                                 fl->fl_icmp_type = icmp[0];
192                                 fl->fl_icmp_code = icmp[1];
193                         }
194                         fl->proto = nexthdr;
195                         return;
196
197 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
198                 case IPPROTO_MH:
199                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
200                                 struct ip6_mh *mh;
201                                 mh = (struct ip6_mh *)exthdr;
202
203                                 fl->fl_mh_type = mh->ip6mh_type;
204                         }
205                         fl->proto = nexthdr;
206                         return;
207 #endif
208
209                 /* XXX Why are there these headers? */
210                 case IPPROTO_AH:
211                 case IPPROTO_ESP:
212                 case IPPROTO_COMP:
213                 default:
214                         fl->fl_ipsec_spi = 0;
215                         fl->proto = nexthdr;
216                         return;
217                 }
218         }
219 }
220
221 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
222 {
223         xfrm6_policy_afinfo.garbage_collect();
224         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
225 }
226
227 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
228 {
229         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
230         struct dst_entry *path = xdst->route;
231
232         path->ops->update_pmtu(path, mtu);
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         xfrm_dst_destroy(xdst);
242 }
243
244 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
245                              int unregister)
246 {
247         struct xfrm_dst *xdst;
248
249         if (!unregister)
250                 return;
251
252         xdst = (struct xfrm_dst *)dst;
253         if (xdst->u.rt6.rt6i_idev->dev == dev) {
254                 struct inet6_dev *loopback_idev =
255                         in6_dev_get(dev_net(dev)->loopback_dev);
256                 BUG_ON(!loopback_idev);
257
258                 do {
259                         in6_dev_put(xdst->u.rt6.rt6i_idev);
260                         xdst->u.rt6.rt6i_idev = loopback_idev;
261                         in6_dev_hold(loopback_idev);
262                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
263                 } while (xdst->u.dst.xfrm);
264
265                 __in6_dev_put(loopback_idev);
266         }
267
268         xfrm_dst_ifdown(dst, dev);
269 }
270
271 static struct dst_ops xfrm6_dst_ops = {
272         .family =               AF_INET6,
273         .protocol =             __constant_htons(ETH_P_IPV6),
274         .gc =                   xfrm6_garbage_collect,
275         .update_pmtu =          xfrm6_update_pmtu,
276         .destroy =              xfrm6_dst_destroy,
277         .ifdown =               xfrm6_dst_ifdown,
278         .local_out =            __ip6_local_out,
279         .gc_thresh =            1024,
280         .entries =              ATOMIC_INIT(0),
281 };
282
283 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
284         .family =               AF_INET6,
285         .dst_ops =              &xfrm6_dst_ops,
286         .dst_lookup =           xfrm6_dst_lookup,
287         .get_saddr =            xfrm6_get_saddr,
288         .find_bundle =          __xfrm6_find_bundle,
289         .decode_session =       _decode_session6,
290         .get_tos =              xfrm6_get_tos,
291         .init_path =            xfrm6_init_path,
292         .fill_dst =             xfrm6_fill_dst,
293 };
294
295 static int __init xfrm6_policy_init(void)
296 {
297         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
298 }
299
300 static void xfrm6_policy_fini(void)
301 {
302         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
303 }
304
305 int __init xfrm6_init(void)
306 {
307         int ret;
308
309         ret = xfrm6_policy_init();
310         if (ret)
311                 goto out;
312
313         ret = xfrm6_state_init();
314         if (ret)
315                 goto out_policy;
316 out:
317         return ret;
318 out_policy:
319         xfrm6_policy_fini();
320         goto out;
321 }
322
323 void xfrm6_fini(void)
324 {
325         //xfrm6_input_fini();
326         xfrm6_policy_fini();
327         xfrm6_state_fini();
328 }