igmp: Use next_net_device_rcu()
[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(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 (xprth + 4 < skb->data ||
140                             pskb_may_pull(skb, xprth + 4 - skb->data)) {
141                                 __be16 *ports = (__be16 *)xprth;
142
143                                 fl->fl_ip_sport = ports[!!reverse];
144                                 fl->fl_ip_dport = ports[!reverse];
145                         }
146                         break;
147
148                 case IPPROTO_ICMP:
149                         if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
150                                 u8 *icmp = xprth;
151
152                                 fl->fl_icmp_type = icmp[0];
153                                 fl->fl_icmp_code = icmp[1];
154                         }
155                         break;
156
157                 case IPPROTO_ESP:
158                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
159                                 __be32 *ehdr = (__be32 *)xprth;
160
161                                 fl->fl_ipsec_spi = ehdr[0];
162                         }
163                         break;
164
165                 case IPPROTO_AH:
166                         if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
167                                 __be32 *ah_hdr = (__be32*)xprth;
168
169                                 fl->fl_ipsec_spi = ah_hdr[1];
170                         }
171                         break;
172
173                 case IPPROTO_COMP:
174                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
175                                 __be16 *ipcomp_hdr = (__be16 *)xprth;
176
177                                 fl->fl_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
178                         }
179                         break;
180                 default:
181                         fl->fl_ipsec_spi = 0;
182                         break;
183                 }
184         }
185         fl->proto = iph->protocol;
186         fl->fl4_dst = reverse ? iph->saddr : iph->daddr;
187         fl->fl4_src = reverse ? iph->daddr : iph->saddr;
188         fl->fl4_tos = iph->tos;
189 }
190
191 static inline int xfrm4_garbage_collect(struct dst_ops *ops)
192 {
193         xfrm4_policy_afinfo.garbage_collect(&init_net);
194         return (atomic_read(&xfrm4_dst_ops.entries) > xfrm4_dst_ops.gc_thresh*2);
195 }
196
197 static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu)
198 {
199         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
200         struct dst_entry *path = xdst->route;
201
202         path->ops->update_pmtu(path, mtu);
203 }
204
205 static void xfrm4_dst_destroy(struct dst_entry *dst)
206 {
207         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
208
209         if (likely(xdst->u.rt.idev))
210                 in_dev_put(xdst->u.rt.idev);
211         if (likely(xdst->u.rt.peer))
212                 inet_putpeer(xdst->u.rt.peer);
213         xfrm_dst_destroy(xdst);
214 }
215
216 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
217                              int unregister)
218 {
219         struct xfrm_dst *xdst;
220
221         if (!unregister)
222                 return;
223
224         xdst = (struct xfrm_dst *)dst;
225         if (xdst->u.rt.idev->dev == dev) {
226                 struct in_device *loopback_idev =
227                         in_dev_get(dev_net(dev)->loopback_dev);
228                 BUG_ON(!loopback_idev);
229
230                 do {
231                         in_dev_put(xdst->u.rt.idev);
232                         xdst->u.rt.idev = loopback_idev;
233                         in_dev_hold(loopback_idev);
234                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
235                 } while (xdst->u.dst.xfrm);
236
237                 __in_dev_put(loopback_idev);
238         }
239
240         xfrm_dst_ifdown(dst, dev);
241 }
242
243 static struct dst_ops xfrm4_dst_ops = {
244         .family =               AF_INET,
245         .protocol =             cpu_to_be16(ETH_P_IP),
246         .gc =                   xfrm4_garbage_collect,
247         .update_pmtu =          xfrm4_update_pmtu,
248         .destroy =              xfrm4_dst_destroy,
249         .ifdown =               xfrm4_dst_ifdown,
250         .local_out =            __ip_local_out,
251         .gc_thresh =            1024,
252         .entries =              ATOMIC_INIT(0),
253 };
254
255 static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
256         .family =               AF_INET,
257         .dst_ops =              &xfrm4_dst_ops,
258         .dst_lookup =           xfrm4_dst_lookup,
259         .get_saddr =            xfrm4_get_saddr,
260         .find_bundle =          __xfrm4_find_bundle,
261         .decode_session =       _decode_session4,
262         .get_tos =              xfrm4_get_tos,
263         .init_path =            xfrm4_init_path,
264         .fill_dst =             xfrm4_fill_dst,
265 };
266
267 #ifdef CONFIG_SYSCTL
268 static struct ctl_table xfrm4_policy_table[] = {
269         {
270                 .ctl_name       = CTL_UNNUMBERED,
271                 .procname       = "xfrm4_gc_thresh",
272                 .data           = &xfrm4_dst_ops.gc_thresh,
273                 .maxlen         = sizeof(int),
274                 .mode           = 0644,
275                 .proc_handler   = proc_dointvec,
276         },
277         { }
278 };
279
280 static struct ctl_table_header *sysctl_hdr;
281 #endif
282
283 static void __init xfrm4_policy_init(void)
284 {
285         xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
286 }
287
288 static void __exit xfrm4_policy_fini(void)
289 {
290 #ifdef CONFIG_SYSCTL
291         if (sysctl_hdr)
292                 unregister_net_sysctl_table(sysctl_hdr);
293 #endif
294         xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo);
295 }
296
297 void __init xfrm4_init(int rt_max_size)
298 {
299         xfrm4_state_init();
300         xfrm4_policy_init();
301         /*
302          * Select a default value for the gc_thresh based on the main route
303          * table hash size.  It seems to me the worst case scenario is when
304          * we have ipsec operating in transport mode, in which we create a
305          * dst_entry per socket.  The xfrm gc algorithm starts trying to remove
306          * entries at gc_thresh, and prevents new allocations as 2*gc_thresh
307          * so lets set an initial xfrm gc_thresh value at the rt_max_size/2.
308          * That will let us store an ipsec connection per route table entry,
309          * and start cleaning when were 1/2 full
310          */
311         xfrm4_dst_ops.gc_thresh = rt_max_size/2;
312 #ifdef CONFIG_SYSCTL
313         sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv4_ctl_path,
314                                                 xfrm4_policy_table);
315 #endif
316 }
317