Merge commit '305b07680f' into orion/master
[linux-2.6] / net / ipv4 / xfrm4_policy.c
1 /*
2  * xfrm4_policy.c
3  *
4  * Changes:
5  *      Kazunori MIYAZAWA @USAGI
6  *      YOSHIFUJI Hideaki @USAGI
7  *              Split up af-specific portion
8  *
9  */
10
11 #include <linux/err.h>
12 #include <linux/kernel.h>
13 #include <linux/inetdevice.h>
14 #include <net/dst.h>
15 #include <net/xfrm.h>
16 #include <net/ip.h>
17
18 static struct dst_ops xfrm4_dst_ops;
19 static struct xfrm_policy_afinfo xfrm4_policy_afinfo;
20
21 static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos,
22                                           xfrm_address_t *saddr,
23                                           xfrm_address_t *daddr)
24 {
25         struct flowi fl = {
26                 .nl_u = {
27                         .ip4_u = {
28                                 .tos = tos,
29                                 .daddr = daddr->a4,
30                         },
31                 },
32         };
33         struct dst_entry *dst;
34         struct rtable *rt;
35         int err;
36
37         if (saddr)
38                 fl.fl4_src = saddr->a4;
39
40         err = __ip_route_output_key(net, &rt, &fl);
41         dst = &rt->u.dst;
42         if (err)
43                 dst = ERR_PTR(err);
44         return dst;
45 }
46
47 static int xfrm4_get_saddr(struct net *net,
48                            xfrm_address_t *saddr, xfrm_address_t *daddr)
49 {
50         struct dst_entry *dst;
51         struct rtable *rt;
52
53         dst = xfrm4_dst_lookup(net, 0, NULL, daddr);
54         if (IS_ERR(dst))
55                 return -EHOSTUNREACH;
56
57         rt = (struct rtable *)dst;
58         saddr->a4 = rt->rt_src;
59         dst_release(dst);
60         return 0;
61 }
62
63 static struct dst_entry *
64 __xfrm4_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
65 {
66         struct dst_entry *dst;
67
68         read_lock_bh(&policy->lock);
69         for (dst = policy->bundles; dst; dst = dst->next) {
70                 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
71                 if (xdst->u.rt.fl.oif == fl->oif &&     /*XXX*/
72                     xdst->u.rt.fl.fl4_dst == fl->fl4_dst &&
73                     xdst->u.rt.fl.fl4_src == fl->fl4_src &&
74                     xdst->u.rt.fl.fl4_tos == fl->fl4_tos &&
75                     xfrm_bundle_ok(policy, xdst, fl, AF_INET, 0)) {
76                         dst_clone(dst);
77                         break;
78                 }
79         }
80         read_unlock_bh(&policy->lock);
81         return dst;
82 }
83
84 static int xfrm4_get_tos(struct flowi *fl)
85 {
86         return fl->fl4_tos;
87 }
88
89 static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst,
90                            int nfheader_len)
91 {
92         return 0;
93 }
94
95 static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
96 {
97         struct rtable *rt = (struct rtable *)xdst->route;
98
99         xdst->u.rt.fl = rt->fl;
100
101         xdst->u.dst.dev = dev;
102         dev_hold(dev);
103
104         xdst->u.rt.idev = in_dev_get(dev);
105         if (!xdst->u.rt.idev)
106                 return -ENODEV;
107
108         xdst->u.rt.peer = rt->peer;
109         if (rt->peer)
110                 atomic_inc(&rt->peer->refcnt);
111
112         /* Sheit... I remember I did this right. Apparently,
113          * it was magically lost, so this code needs audit */
114         xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
115                                               RTCF_LOCAL);
116         xdst->u.rt.rt_type = rt->rt_type;
117         xdst->u.rt.rt_src = rt->rt_src;
118         xdst->u.rt.rt_dst = rt->rt_dst;
119         xdst->u.rt.rt_gateway = rt->rt_gateway;
120         xdst->u.rt.rt_spec_dst = rt->rt_spec_dst;
121
122         return 0;
123 }
124
125 static void
126 _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
127 {
128         struct iphdr *iph = ip_hdr(skb);
129         u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
130
131         memset(fl, 0, sizeof(struct flowi));
132         if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) {
133                 switch (iph->protocol) {
134                 case IPPROTO_UDP:
135                 case IPPROTO_UDPLITE:
136                 case IPPROTO_TCP:
137                 case IPPROTO_SCTP:
138                 case IPPROTO_DCCP:
139                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
140                                 __be16 *ports = (__be16 *)xprth;
141
142                                 fl->fl_ip_sport = ports[!!reverse];
143                                 fl->fl_ip_dport = ports[!reverse];
144                         }
145                         break;
146
147                 case IPPROTO_ICMP:
148                         if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
149                                 u8 *icmp = xprth;
150
151                                 fl->fl_icmp_type = icmp[0];
152                                 fl->fl_icmp_code = icmp[1];
153                         }
154                         break;
155
156                 case IPPROTO_ESP:
157                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
158                                 __be32 *ehdr = (__be32 *)xprth;
159
160                                 fl->fl_ipsec_spi = ehdr[0];
161                         }
162                         break;
163
164                 case IPPROTO_AH:
165                         if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
166                                 __be32 *ah_hdr = (__be32*)xprth;
167
168                                 fl->fl_ipsec_spi = ah_hdr[1];
169                         }
170                         break;
171
172                 case IPPROTO_COMP:
173                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
174                                 __be16 *ipcomp_hdr = (__be16 *)xprth;
175
176                                 fl->fl_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
177                         }
178                         break;
179                 default:
180                         fl->fl_ipsec_spi = 0;
181                         break;
182                 }
183         }
184         fl->proto = iph->protocol;
185         fl->fl4_dst = reverse ? iph->saddr : iph->daddr;
186         fl->fl4_src = reverse ? iph->daddr : iph->saddr;
187         fl->fl4_tos = iph->tos;
188 }
189
190 static inline int xfrm4_garbage_collect(struct dst_ops *ops)
191 {
192         xfrm4_policy_afinfo.garbage_collect(&init_net);
193         return (atomic_read(&xfrm4_dst_ops.entries) > xfrm4_dst_ops.gc_thresh*2);
194 }
195
196 static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu)
197 {
198         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
199         struct dst_entry *path = xdst->route;
200
201         path->ops->update_pmtu(path, mtu);
202 }
203
204 static void xfrm4_dst_destroy(struct dst_entry *dst)
205 {
206         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
207
208         if (likely(xdst->u.rt.idev))
209                 in_dev_put(xdst->u.rt.idev);
210         if (likely(xdst->u.rt.peer))
211                 inet_putpeer(xdst->u.rt.peer);
212         xfrm_dst_destroy(xdst);
213 }
214
215 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
216                              int unregister)
217 {
218         struct xfrm_dst *xdst;
219
220         if (!unregister)
221                 return;
222
223         xdst = (struct xfrm_dst *)dst;
224         if (xdst->u.rt.idev->dev == dev) {
225                 struct in_device *loopback_idev =
226                         in_dev_get(dev_net(dev)->loopback_dev);
227                 BUG_ON(!loopback_idev);
228
229                 do {
230                         in_dev_put(xdst->u.rt.idev);
231                         xdst->u.rt.idev = loopback_idev;
232                         in_dev_hold(loopback_idev);
233                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
234                 } while (xdst->u.dst.xfrm);
235
236                 __in_dev_put(loopback_idev);
237         }
238
239         xfrm_dst_ifdown(dst, dev);
240 }
241
242 static struct dst_ops xfrm4_dst_ops = {
243         .family =               AF_INET,
244         .protocol =             __constant_htons(ETH_P_IP),
245         .gc =                   xfrm4_garbage_collect,
246         .update_pmtu =          xfrm4_update_pmtu,
247         .destroy =              xfrm4_dst_destroy,
248         .ifdown =               xfrm4_dst_ifdown,
249         .local_out =            __ip_local_out,
250         .gc_thresh =            1024,
251         .entries =              ATOMIC_INIT(0),
252 };
253
254 static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
255         .family =               AF_INET,
256         .dst_ops =              &xfrm4_dst_ops,
257         .dst_lookup =           xfrm4_dst_lookup,
258         .get_saddr =            xfrm4_get_saddr,
259         .find_bundle =          __xfrm4_find_bundle,
260         .decode_session =       _decode_session4,
261         .get_tos =              xfrm4_get_tos,
262         .init_path =            xfrm4_init_path,
263         .fill_dst =             xfrm4_fill_dst,
264 };
265
266 static void __init xfrm4_policy_init(void)
267 {
268         xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
269 }
270
271 static void __exit xfrm4_policy_fini(void)
272 {
273         xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo);
274 }
275
276 void __init xfrm4_init(void)
277 {
278         xfrm4_state_init();
279         xfrm4_policy_init();
280 }
281