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