netfilter: x_tables: use NFPROTO_* in extensions
[linux-2.6.git] / 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(&init_net, &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_init_path(struct xfrm_dst *path, struct dst_entry *dst,
88                            int nfheader_len)
89 {
90         return 0;
91 }
92
93 static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
94 {
95         struct rtable *rt = (struct rtable *)xdst->route;
96
97         xdst->u.rt.fl = rt->fl;
98
99         xdst->u.dst.dev = dev;
100         dev_hold(dev);
101
102         xdst->u.rt.idev = in_dev_get(dev);
103         if (!xdst->u.rt.idev)
104                 return -ENODEV;
105
106         xdst->u.rt.peer = rt->peer;
107         if (rt->peer)
108                 atomic_inc(&rt->peer->refcnt);
109
110         /* Sheit... I remember I did this right. Apparently,
111          * it was magically lost, so this code needs audit */
112         xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
113                                               RTCF_LOCAL);
114         xdst->u.rt.rt_type = rt->rt_type;
115         xdst->u.rt.rt_src = rt->rt_src;
116         xdst->u.rt.rt_dst = rt->rt_dst;
117         xdst->u.rt.rt_gateway = rt->rt_gateway;
118         xdst->u.rt.rt_spec_dst = rt->rt_spec_dst;
119
120         return 0;
121 }
122
123 static void
124 _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
125 {
126         struct iphdr *iph = ip_hdr(skb);
127         u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
128
129         memset(fl, 0, sizeof(struct flowi));
130         if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) {
131                 switch (iph->protocol) {
132                 case IPPROTO_UDP:
133                 case IPPROTO_UDPLITE:
134                 case IPPROTO_TCP:
135                 case IPPROTO_SCTP:
136                 case IPPROTO_DCCP:
137                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
138                                 __be16 *ports = (__be16 *)xprth;
139
140                                 fl->fl_ip_sport = ports[!!reverse];
141                                 fl->fl_ip_dport = ports[!reverse];
142                         }
143                         break;
144
145                 case IPPROTO_ICMP:
146                         if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
147                                 u8 *icmp = xprth;
148
149                                 fl->fl_icmp_type = icmp[0];
150                                 fl->fl_icmp_code = icmp[1];
151                         }
152                         break;
153
154                 case IPPROTO_ESP:
155                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
156                                 __be32 *ehdr = (__be32 *)xprth;
157
158                                 fl->fl_ipsec_spi = ehdr[0];
159                         }
160                         break;
161
162                 case IPPROTO_AH:
163                         if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
164                                 __be32 *ah_hdr = (__be32*)xprth;
165
166                                 fl->fl_ipsec_spi = ah_hdr[1];
167                         }
168                         break;
169
170                 case IPPROTO_COMP:
171                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
172                                 __be16 *ipcomp_hdr = (__be16 *)xprth;
173
174                                 fl->fl_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
175                         }
176                         break;
177                 default:
178                         fl->fl_ipsec_spi = 0;
179                         break;
180                 }
181         }
182         fl->proto = iph->protocol;
183         fl->fl4_dst = reverse ? iph->saddr : iph->daddr;
184         fl->fl4_src = reverse ? iph->daddr : iph->saddr;
185         fl->fl4_tos = iph->tos;
186 }
187
188 static inline int xfrm4_garbage_collect(struct dst_ops *ops)
189 {
190         xfrm4_policy_afinfo.garbage_collect();
191         return (atomic_read(&xfrm4_dst_ops.entries) > xfrm4_dst_ops.gc_thresh*2);
192 }
193
194 static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu)
195 {
196         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
197         struct dst_entry *path = xdst->route;
198
199         path->ops->update_pmtu(path, mtu);
200 }
201
202 static void xfrm4_dst_destroy(struct dst_entry *dst)
203 {
204         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
205
206         if (likely(xdst->u.rt.idev))
207                 in_dev_put(xdst->u.rt.idev);
208         if (likely(xdst->u.rt.peer))
209                 inet_putpeer(xdst->u.rt.peer);
210         xfrm_dst_destroy(xdst);
211 }
212
213 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
214                              int unregister)
215 {
216         struct xfrm_dst *xdst;
217
218         if (!unregister)
219                 return;
220
221         xdst = (struct xfrm_dst *)dst;
222         if (xdst->u.rt.idev->dev == dev) {
223                 struct in_device *loopback_idev =
224                         in_dev_get(dev_net(dev)->loopback_dev);
225                 BUG_ON(!loopback_idev);
226
227                 do {
228                         in_dev_put(xdst->u.rt.idev);
229                         xdst->u.rt.idev = loopback_idev;
230                         in_dev_hold(loopback_idev);
231                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
232                 } while (xdst->u.dst.xfrm);
233
234                 __in_dev_put(loopback_idev);
235         }
236
237         xfrm_dst_ifdown(dst, dev);
238 }
239
240 static struct dst_ops xfrm4_dst_ops = {
241         .family =               AF_INET,
242         .protocol =             __constant_htons(ETH_P_IP),
243         .gc =                   xfrm4_garbage_collect,
244         .update_pmtu =          xfrm4_update_pmtu,
245         .destroy =              xfrm4_dst_destroy,
246         .ifdown =               xfrm4_dst_ifdown,
247         .local_out =            __ip_local_out,
248         .gc_thresh =            1024,
249         .entry_size =           sizeof(struct xfrm_dst),
250         .entries =              ATOMIC_INIT(0),
251 };
252
253 static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
254         .family =               AF_INET,
255         .dst_ops =              &xfrm4_dst_ops,
256         .dst_lookup =           xfrm4_dst_lookup,
257         .get_saddr =            xfrm4_get_saddr,
258         .find_bundle =          __xfrm4_find_bundle,
259         .decode_session =       _decode_session4,
260         .get_tos =              xfrm4_get_tos,
261         .init_path =            xfrm4_init_path,
262         .fill_dst =             xfrm4_fill_dst,
263 };
264
265 static void __init xfrm4_policy_init(void)
266 {
267         xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
268 }
269
270 static void __exit xfrm4_policy_fini(void)
271 {
272         xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo);
273 }
274
275 void __init xfrm4_init(void)
276 {
277         xfrm4_state_init();
278         xfrm4_policy_init();
279 }
280