[TCP]: sysctl to allow TCP window > 32767 sans wscale
[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/compiler.h>
12 #include <linux/config.h>
13 #include <linux/inetdevice.h>
14 #include <net/xfrm.h>
15 #include <net/ip.h>
16
17 static struct dst_ops xfrm4_dst_ops;
18 static struct xfrm_policy_afinfo xfrm4_policy_afinfo;
19
20 static struct xfrm_type_map xfrm4_type_map = { .lock = RW_LOCK_UNLOCKED };
21
22 static int xfrm4_dst_lookup(struct xfrm_dst **dst, struct flowi *fl)
23 {
24         return __ip_route_output_key((struct rtable**)dst, fl);
25 }
26
27 static struct dst_entry *
28 __xfrm4_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
29 {
30         struct dst_entry *dst;
31
32         read_lock_bh(&policy->lock);
33         for (dst = policy->bundles; dst; dst = dst->next) {
34                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
35                 if (xdst->u.rt.fl.oif == fl->oif &&     /*XXX*/
36                     xdst->u.rt.fl.fl4_dst == fl->fl4_dst &&
37                     xdst->u.rt.fl.fl4_src == fl->fl4_src &&
38                     xdst->u.rt.fl.fl4_tos == fl->fl4_tos &&
39                     xfrm_bundle_ok(xdst, fl, AF_INET)) {
40                         dst_clone(dst);
41                         break;
42                 }
43         }
44         read_unlock_bh(&policy->lock);
45         return dst;
46 }
47
48 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
49  * all the metrics... Shortly, bundle a bundle.
50  */
51
52 static int
53 __xfrm4_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
54                       struct flowi *fl, struct dst_entry **dst_p)
55 {
56         struct dst_entry *dst, *dst_prev;
57         struct rtable *rt0 = (struct rtable*)(*dst_p);
58         struct rtable *rt = rt0;
59         u32 remote = fl->fl4_dst;
60         u32 local  = fl->fl4_src;
61         struct flowi fl_tunnel = {
62                 .nl_u = {
63                         .ip4_u = {
64                                 .saddr = local,
65                                 .daddr = remote,
66                                 .tos = fl->fl4_tos
67                         }
68                 }
69         };
70         int i;
71         int err;
72         int header_len = 0;
73         int trailer_len = 0;
74
75         dst = dst_prev = NULL;
76         dst_hold(&rt->u.dst);
77
78         for (i = 0; i < nx; i++) {
79                 struct dst_entry *dst1 = dst_alloc(&xfrm4_dst_ops);
80                 struct xfrm_dst *xdst;
81                 int tunnel = 0;
82
83                 if (unlikely(dst1 == NULL)) {
84                         err = -ENOBUFS;
85                         dst_release(&rt->u.dst);
86                         goto error;
87                 }
88
89                 if (!dst)
90                         dst = dst1;
91                 else {
92                         dst_prev->child = dst1;
93                         dst1->flags |= DST_NOHASH;
94                         dst_clone(dst1);
95                 }
96
97                 xdst = (struct xfrm_dst *)dst1;
98                 xdst->route = &rt->u.dst;
99
100                 dst1->next = dst_prev;
101                 dst_prev = dst1;
102                 if (xfrm[i]->props.mode) {
103                         remote = xfrm[i]->id.daddr.a4;
104                         local  = xfrm[i]->props.saddr.a4;
105                         tunnel = 1;
106                 }
107                 header_len += xfrm[i]->props.header_len;
108                 trailer_len += xfrm[i]->props.trailer_len;
109
110                 if (tunnel) {
111                         fl_tunnel.fl4_src = local;
112                         fl_tunnel.fl4_dst = remote;
113                         err = xfrm_dst_lookup((struct xfrm_dst **)&rt,
114                                               &fl_tunnel, AF_INET);
115                         if (err)
116                                 goto error;
117                 } else
118                         dst_hold(&rt->u.dst);
119         }
120
121         dst_prev->child = &rt->u.dst;
122         dst->path = &rt->u.dst;
123
124         *dst_p = dst;
125         dst = dst_prev;
126
127         dst_prev = *dst_p;
128         i = 0;
129         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
130                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
131                 x->u.rt.fl = *fl;
132
133                 dst_prev->xfrm = xfrm[i++];
134                 dst_prev->dev = rt->u.dst.dev;
135                 if (rt->u.dst.dev)
136                         dev_hold(rt->u.dst.dev);
137                 dst_prev->obsolete      = -1;
138                 dst_prev->flags        |= DST_HOST;
139                 dst_prev->lastuse       = jiffies;
140                 dst_prev->header_len    = header_len;
141                 dst_prev->trailer_len   = trailer_len;
142                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
143
144                 /* Copy neighbout for reachability confirmation */
145                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
146                 dst_prev->input         = rt->u.dst.input;
147                 dst_prev->output        = xfrm4_output;
148                 if (rt->peer)
149                         atomic_inc(&rt->peer->refcnt);
150                 x->u.rt.peer = rt->peer;
151                 /* Sheit... I remember I did this right. Apparently,
152                  * it was magically lost, so this code needs audit */
153                 x->u.rt.rt_flags = rt0->rt_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
154                 x->u.rt.rt_type = rt->rt_type;
155                 x->u.rt.rt_src = rt0->rt_src;
156                 x->u.rt.rt_dst = rt0->rt_dst;
157                 x->u.rt.rt_gateway = rt->rt_gateway;
158                 x->u.rt.rt_spec_dst = rt0->rt_spec_dst;
159                 x->u.rt.idev = rt0->idev;
160                 in_dev_hold(rt0->idev);
161                 header_len -= x->u.dst.xfrm->props.header_len;
162                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
163         }
164
165         xfrm_init_pmtu(dst);
166         return 0;
167
168 error:
169         if (dst)
170                 dst_free(dst);
171         return err;
172 }
173
174 static void
175 _decode_session4(struct sk_buff *skb, struct flowi *fl)
176 {
177         struct iphdr *iph = skb->nh.iph;
178         u8 *xprth = skb->nh.raw + iph->ihl*4;
179
180         memset(fl, 0, sizeof(struct flowi));
181         if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) {
182                 switch (iph->protocol) {
183                 case IPPROTO_UDP:
184                 case IPPROTO_TCP:
185                 case IPPROTO_SCTP:
186                 case IPPROTO_DCCP:
187                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
188                                 u16 *ports = (u16 *)xprth;
189
190                                 fl->fl_ip_sport = ports[0];
191                                 fl->fl_ip_dport = ports[1];
192                         }
193                         break;
194
195                 case IPPROTO_ICMP:
196                         if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
197                                 u8 *icmp = xprth;
198
199                                 fl->fl_icmp_type = icmp[0];
200                                 fl->fl_icmp_code = icmp[1];
201                         }
202                         break;
203
204                 case IPPROTO_ESP:
205                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
206                                 u32 *ehdr = (u32 *)xprth;
207
208                                 fl->fl_ipsec_spi = ehdr[0];
209                         }
210                         break;
211
212                 case IPPROTO_AH:
213                         if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
214                                 u32 *ah_hdr = (u32*)xprth;
215
216                                 fl->fl_ipsec_spi = ah_hdr[1];
217                         }
218                         break;
219
220                 case IPPROTO_COMP:
221                         if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
222                                 u16 *ipcomp_hdr = (u16 *)xprth;
223
224                                 fl->fl_ipsec_spi = ntohl(ntohs(ipcomp_hdr[1]));
225                         }
226                         break;
227                 default:
228                         fl->fl_ipsec_spi = 0;
229                         break;
230                 };
231         }
232         fl->proto = iph->protocol;
233         fl->fl4_dst = iph->daddr;
234         fl->fl4_src = iph->saddr;
235         fl->fl4_tos = iph->tos;
236 }
237
238 static inline int xfrm4_garbage_collect(void)
239 {
240         read_lock(&xfrm4_policy_afinfo.lock);
241         xfrm4_policy_afinfo.garbage_collect();
242         read_unlock(&xfrm4_policy_afinfo.lock);
243         return (atomic_read(&xfrm4_dst_ops.entries) > xfrm4_dst_ops.gc_thresh*2);
244 }
245
246 static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu)
247 {
248         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
249         struct dst_entry *path = xdst->route;
250
251         path->ops->update_pmtu(path, mtu);
252 }
253
254 static void xfrm4_dst_destroy(struct dst_entry *dst)
255 {
256         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
257
258         if (likely(xdst->u.rt.idev))
259                 in_dev_put(xdst->u.rt.idev);
260         xfrm_dst_destroy(xdst);
261 }
262
263 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
264                              int unregister)
265 {
266         struct xfrm_dst *xdst;
267
268         if (!unregister)
269                 return;
270
271         xdst = (struct xfrm_dst *)dst;
272         if (xdst->u.rt.idev->dev == dev) {
273                 struct in_device *loopback_idev = in_dev_get(&loopback_dev);
274                 BUG_ON(!loopback_idev);
275
276                 do {
277                         in_dev_put(xdst->u.rt.idev);
278                         xdst->u.rt.idev = loopback_idev;
279                         in_dev_hold(loopback_idev);
280                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
281                 } while (xdst->u.dst.xfrm);
282
283                 __in_dev_put(loopback_idev);
284         }
285
286         xfrm_dst_ifdown(dst, dev);
287 }
288
289 static struct dst_ops xfrm4_dst_ops = {
290         .family =               AF_INET,
291         .protocol =             __constant_htons(ETH_P_IP),
292         .gc =                   xfrm4_garbage_collect,
293         .update_pmtu =          xfrm4_update_pmtu,
294         .destroy =              xfrm4_dst_destroy,
295         .ifdown =               xfrm4_dst_ifdown,
296         .gc_thresh =            1024,
297         .entry_size =           sizeof(struct xfrm_dst),
298 };
299
300 static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
301         .family =               AF_INET,
302         .lock =                 RW_LOCK_UNLOCKED,
303         .type_map =             &xfrm4_type_map,
304         .dst_ops =              &xfrm4_dst_ops,
305         .dst_lookup =           xfrm4_dst_lookup,
306         .find_bundle =          __xfrm4_find_bundle,
307         .bundle_create =        __xfrm4_bundle_create,
308         .decode_session =       _decode_session4,
309 };
310
311 static void __init xfrm4_policy_init(void)
312 {
313         xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
314 }
315
316 static void __exit xfrm4_policy_fini(void)
317 {
318         xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo);
319 }
320
321 void __init xfrm4_init(void)
322 {
323         xfrm4_state_init();
324         xfrm4_policy_init();
325 }
326