inet: Fix __inet_inherit_port() to correctly increment bsockets and num_owners
[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 xfrm_policy_afinfo xfrm4_policy_afinfo;
19
20 static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos,
21                                           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(net, &rt, &fl);
40         dst = &rt->dst;
41         if (err)
42                 dst = ERR_PTR(err);
43         return dst;
44 }
45
46 static int xfrm4_get_saddr(struct net *net,
47                            xfrm_address_t *saddr, xfrm_address_t *daddr)
48 {
49         struct dst_entry *dst;
50         struct rtable *rt;
51
52         dst = xfrm4_dst_lookup(net, 0, NULL, daddr);
53         if (IS_ERR(dst))
54                 return -EHOSTUNREACH;
55
56         rt = (struct rtable *)dst;
57         saddr->a4 = rt->rt_src;
58         dst_release(dst);
59         return 0;
60 }
61
62 static int xfrm4_get_tos(struct flowi *fl)
63 {
64         return IPTOS_RT_MASK & fl->fl4_tos; /* Strip ECN bits */
65 }
66
67 static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst,
68                            int nfheader_len)
69 {
70         return 0;
71 }
72
73 static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
74                           struct flowi *fl)
75 {
76         struct rtable *rt = (struct rtable *)xdst->route;
77
78         xdst->u.rt.fl = *fl;
79
80         xdst->u.dst.dev = dev;
81         dev_hold(dev);
82
83         xdst->u.rt.idev = in_dev_get(dev);
84         if (!xdst->u.rt.idev)
85                 return -ENODEV;
86
87         xdst->u.rt.peer = rt->peer;
88         if (rt->peer)
89                 atomic_inc(&rt->peer->refcnt);
90
91         /* Sheit... I remember I did this right. Apparently,
92          * it was magically lost, so this code needs audit */
93         xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
94                                               RTCF_LOCAL);
95         xdst->u.rt.rt_type = rt->rt_type;
96         xdst->u.rt.rt_src = rt->rt_src;
97         xdst->u.rt.rt_dst = rt->rt_dst;
98         xdst->u.rt.rt_gateway = rt->rt_gateway;
99         xdst->u.rt.rt_spec_dst = rt->rt_spec_dst;
100
101         return 0;
102 }
103
104 static void
105 _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
106 {
107         struct iphdr *iph = ip_hdr(skb);
108         u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
109
110         memset(fl, 0, sizeof(struct flowi));
111         fl->mark = skb->mark;
112
113         if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) {
114                 switch (iph->protocol) {
115                 case IPPROTO_UDP:
116                 case IPPROTO_UDPLITE:
117                 case IPPROTO_TCP:
118                 case IPPROTO_SCTP:
119                 case IPPROTO_DCCP:
120                         if (xprth + 4 < skb->data ||
121                             pskb_may_pull(skb, xprth + 4 - skb->data)) {
122                                 __be16 *ports = (__be16 *)xprth;
123
124                                 fl->fl_ip_sport = ports[!!reverse];
125                                 fl->fl_ip_dport = ports[!reverse];
126                         }
127                         break;
128
129                 case IPPROTO_ICMP:
130                         if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
131                                 u8 *icmp = xprth;
132
133                                 fl->fl_icmp_type = icmp[0];
134                                 fl->fl_icmp_code = icmp[1];
135                         }
136                         break;
137
138                 case IPPROTO_ESP:
139                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
140                                 __be32 *ehdr = (__be32 *)xprth;
141
142                                 fl->fl_ipsec_spi = ehdr[0];
143                         }
144                         break;
145
146                 case IPPROTO_AH:
147                         if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
148                                 __be32 *ah_hdr = (__be32*)xprth;
149
150                                 fl->fl_ipsec_spi = ah_hdr[1];
151                         }
152                         break;
153
154                 case IPPROTO_COMP:
155                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
156                                 __be16 *ipcomp_hdr = (__be16 *)xprth;
157
158                                 fl->fl_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
159                         }
160                         break;
161                 default:
162                         fl->fl_ipsec_spi = 0;
163                         break;
164                 }
165         }
166         fl->proto = iph->protocol;
167         fl->fl4_dst = reverse ? iph->saddr : iph->daddr;
168         fl->fl4_src = reverse ? iph->daddr : iph->saddr;
169         fl->fl4_tos = iph->tos;
170 }
171
172 static inline int xfrm4_garbage_collect(struct dst_ops *ops)
173 {
174         struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops);
175
176         xfrm4_policy_afinfo.garbage_collect(net);
177         return (dst_entries_get_slow(ops) > ops->gc_thresh * 2);
178 }
179
180 static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu)
181 {
182         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
183         struct dst_entry *path = xdst->route;
184
185         path->ops->update_pmtu(path, mtu);
186 }
187
188 static void xfrm4_dst_destroy(struct dst_entry *dst)
189 {
190         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
191
192         if (likely(xdst->u.rt.idev))
193                 in_dev_put(xdst->u.rt.idev);
194         if (likely(xdst->u.rt.peer))
195                 inet_putpeer(xdst->u.rt.peer);
196         xfrm_dst_destroy(xdst);
197 }
198
199 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
200                              int unregister)
201 {
202         struct xfrm_dst *xdst;
203
204         if (!unregister)
205                 return;
206
207         xdst = (struct xfrm_dst *)dst;
208         if (xdst->u.rt.idev->dev == dev) {
209                 struct in_device *loopback_idev =
210                         in_dev_get(dev_net(dev)->loopback_dev);
211                 BUG_ON(!loopback_idev);
212
213                 do {
214                         in_dev_put(xdst->u.rt.idev);
215                         xdst->u.rt.idev = loopback_idev;
216                         in_dev_hold(loopback_idev);
217                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
218                 } while (xdst->u.dst.xfrm);
219
220                 __in_dev_put(loopback_idev);
221         }
222
223         xfrm_dst_ifdown(dst, dev);
224 }
225
226 static struct dst_ops xfrm4_dst_ops = {
227         .family =               AF_INET,
228         .protocol =             cpu_to_be16(ETH_P_IP),
229         .gc =                   xfrm4_garbage_collect,
230         .update_pmtu =          xfrm4_update_pmtu,
231         .destroy =              xfrm4_dst_destroy,
232         .ifdown =               xfrm4_dst_ifdown,
233         .local_out =            __ip_local_out,
234         .gc_thresh =            1024,
235 };
236
237 static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
238         .family =               AF_INET,
239         .dst_ops =              &xfrm4_dst_ops,
240         .dst_lookup =           xfrm4_dst_lookup,
241         .get_saddr =            xfrm4_get_saddr,
242         .decode_session =       _decode_session4,
243         .get_tos =              xfrm4_get_tos,
244         .init_path =            xfrm4_init_path,
245         .fill_dst =             xfrm4_fill_dst,
246 };
247
248 #ifdef CONFIG_SYSCTL
249 static struct ctl_table xfrm4_policy_table[] = {
250         {
251                 .procname       = "xfrm4_gc_thresh",
252                 .data           = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
253                 .maxlen         = sizeof(int),
254                 .mode           = 0644,
255                 .proc_handler   = proc_dointvec,
256         },
257         { }
258 };
259
260 static struct ctl_table_header *sysctl_hdr;
261 #endif
262
263 static void __init xfrm4_policy_init(void)
264 {
265         xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
266 }
267
268 static void __exit xfrm4_policy_fini(void)
269 {
270 #ifdef CONFIG_SYSCTL
271         if (sysctl_hdr)
272                 unregister_net_sysctl_table(sysctl_hdr);
273 #endif
274         xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo);
275 }
276
277 void __init xfrm4_init(int rt_max_size)
278 {
279         /*
280          * Select a default value for the gc_thresh based on the main route
281          * table hash size.  It seems to me the worst case scenario is when
282          * we have ipsec operating in transport mode, in which we create a
283          * dst_entry per socket.  The xfrm gc algorithm starts trying to remove
284          * entries at gc_thresh, and prevents new allocations as 2*gc_thresh
285          * so lets set an initial xfrm gc_thresh value at the rt_max_size/2.
286          * That will let us store an ipsec connection per route table entry,
287          * and start cleaning when were 1/2 full
288          */
289         xfrm4_dst_ops.gc_thresh = rt_max_size/2;
290         dst_entries_init(&xfrm4_dst_ops);
291
292         xfrm4_state_init();
293         xfrm4_policy_init();
294 #ifdef CONFIG_SYSCTL
295         sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv4_ctl_path,
296                                                 xfrm4_policy_table);
297 #endif
298 }
299