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[net-next-2.6.git] / net / ipv4 / xfrm4_policy.c
CommitLineData
1da177e4
LT
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
aabc9761 11#include <linux/compiler.h>
aabc9761 12#include <linux/inetdevice.h>
1da177e4
LT
13#include <net/xfrm.h>
14#include <net/ip.h>
15
16static struct dst_ops xfrm4_dst_ops;
17static struct xfrm_policy_afinfo xfrm4_policy_afinfo;
18
1da177e4
LT
19static int xfrm4_dst_lookup(struct xfrm_dst **dst, struct flowi *fl)
20{
21 return __ip_route_output_key((struct rtable**)dst, fl);
22}
23
a1e59abf
PM
24static int xfrm4_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
25{
26 struct rtable *rt;
27 struct flowi fl_tunnel = {
28 .nl_u = {
29 .ip4_u = {
30 .daddr = daddr->a4,
31 },
32 },
33 };
34
35 if (!xfrm4_dst_lookup((struct xfrm_dst **)&rt, &fl_tunnel)) {
36 saddr->a4 = rt->rt_src;
37 dst_release(&rt->u.dst);
38 return 0;
39 }
40 return -EHOSTUNREACH;
41}
42
1da177e4
LT
43static struct dst_entry *
44__xfrm4_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
45{
46 struct dst_entry *dst;
47
48 read_lock_bh(&policy->lock);
49 for (dst = policy->bundles; dst; dst = dst->next) {
50 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
51 if (xdst->u.rt.fl.oif == fl->oif && /*XXX*/
52 xdst->u.rt.fl.fl4_dst == fl->fl4_dst &&
53 xdst->u.rt.fl.fl4_src == fl->fl4_src &&
4da3089f 54 xdst->u.rt.fl.fl4_tos == fl->fl4_tos &&
5b368e61 55 xfrm_bundle_ok(policy, xdst, fl, AF_INET, 0)) {
1da177e4
LT
56 dst_clone(dst);
57 break;
58 }
59 }
60 read_unlock_bh(&policy->lock);
61 return dst;
62}
63
64/* Allocate chain of dst_entry's, attach known xfrm's, calculate
65 * all the metrics... Shortly, bundle a bundle.
66 */
67
68static int
69__xfrm4_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
70 struct flowi *fl, struct dst_entry **dst_p)
71{
72 struct dst_entry *dst, *dst_prev;
73 struct rtable *rt0 = (struct rtable*)(*dst_p);
74 struct rtable *rt = rt0;
8c689a6e
AV
75 __be32 remote = fl->fl4_dst;
76 __be32 local = fl->fl4_src;
1da177e4
LT
77 struct flowi fl_tunnel = {
78 .nl_u = {
79 .ip4_u = {
80 .saddr = local,
4da3089f
HX
81 .daddr = remote,
82 .tos = fl->fl4_tos
1da177e4
LT
83 }
84 }
85 };
86 int i;
87 int err;
88 int header_len = 0;
89 int trailer_len = 0;
90
91 dst = dst_prev = NULL;
92 dst_hold(&rt->u.dst);
93
94 for (i = 0; i < nx; i++) {
95 struct dst_entry *dst1 = dst_alloc(&xfrm4_dst_ops);
96 struct xfrm_dst *xdst;
97 int tunnel = 0;
98
99 if (unlikely(dst1 == NULL)) {
100 err = -ENOBUFS;
101 dst_release(&rt->u.dst);
102 goto error;
103 }
104
105 if (!dst)
106 dst = dst1;
107 else {
108 dst_prev->child = dst1;
109 dst1->flags |= DST_NOHASH;
110 dst_clone(dst1);
111 }
112
113 xdst = (struct xfrm_dst *)dst1;
114 xdst->route = &rt->u.dst;
9d4a706d 115 xdst->genid = xfrm[i]->genid;
1da177e4
LT
116
117 dst1->next = dst_prev;
118 dst_prev = dst1;
7e49e6de 119 if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
1da177e4
LT
120 remote = xfrm[i]->id.daddr.a4;
121 local = xfrm[i]->props.saddr.a4;
122 tunnel = 1;
123 }
124 header_len += xfrm[i]->props.header_len;
125 trailer_len += xfrm[i]->props.trailer_len;
126
127 if (tunnel) {
128 fl_tunnel.fl4_src = local;
129 fl_tunnel.fl4_dst = remote;
130 err = xfrm_dst_lookup((struct xfrm_dst **)&rt,
131 &fl_tunnel, AF_INET);
132 if (err)
133 goto error;
134 } else
135 dst_hold(&rt->u.dst);
136 }
137
138 dst_prev->child = &rt->u.dst;
139 dst->path = &rt->u.dst;
140
141 *dst_p = dst;
142 dst = dst_prev;
143
144 dst_prev = *dst_p;
145 i = 0;
146 for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
147 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
148 x->u.rt.fl = *fl;
149
150 dst_prev->xfrm = xfrm[i++];
151 dst_prev->dev = rt->u.dst.dev;
152 if (rt->u.dst.dev)
153 dev_hold(rt->u.dst.dev);
154 dst_prev->obsolete = -1;
155 dst_prev->flags |= DST_HOST;
156 dst_prev->lastuse = jiffies;
157 dst_prev->header_len = header_len;
1b5c2299 158 dst_prev->nfheader_len = 0;
1da177e4
LT
159 dst_prev->trailer_len = trailer_len;
160 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
161
162 /* Copy neighbout for reachability confirmation */
163 dst_prev->neighbour = neigh_clone(rt->u.dst.neighbour);
164 dst_prev->input = rt->u.dst.input;
165 dst_prev->output = xfrm4_output;
166 if (rt->peer)
167 atomic_inc(&rt->peer->refcnt);
168 x->u.rt.peer = rt->peer;
169 /* Sheit... I remember I did this right. Apparently,
170 * it was magically lost, so this code needs audit */
171 x->u.rt.rt_flags = rt0->rt_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
172 x->u.rt.rt_type = rt->rt_type;
173 x->u.rt.rt_src = rt0->rt_src;
174 x->u.rt.rt_dst = rt0->rt_dst;
175 x->u.rt.rt_gateway = rt->rt_gateway;
176 x->u.rt.rt_spec_dst = rt0->rt_spec_dst;
aabc9761
HX
177 x->u.rt.idev = rt0->idev;
178 in_dev_hold(rt0->idev);
1da177e4
LT
179 header_len -= x->u.dst.xfrm->props.header_len;
180 trailer_len -= x->u.dst.xfrm->props.trailer_len;
181 }
182
183 xfrm_init_pmtu(dst);
184 return 0;
185
186error:
187 if (dst)
188 dst_free(dst);
189 return err;
190}
191
192static void
193_decode_session4(struct sk_buff *skb, struct flowi *fl)
194{
195 struct iphdr *iph = skb->nh.iph;
196 u8 *xprth = skb->nh.raw + iph->ihl*4;
197
198 memset(fl, 0, sizeof(struct flowi));
199 if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) {
200 switch (iph->protocol) {
201 case IPPROTO_UDP:
202 case IPPROTO_TCP:
203 case IPPROTO_SCTP:
9e999993 204 case IPPROTO_DCCP:
1da177e4 205 if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
8c689a6e 206 __be16 *ports = (__be16 *)xprth;
1da177e4
LT
207
208 fl->fl_ip_sport = ports[0];
209 fl->fl_ip_dport = ports[1];
210 }
211 break;
212
213 case IPPROTO_ICMP:
214 if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
215 u8 *icmp = xprth;
216
217 fl->fl_icmp_type = icmp[0];
218 fl->fl_icmp_code = icmp[1];
219 }
220 break;
221
222 case IPPROTO_ESP:
223 if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
4324a174 224 __be32 *ehdr = (__be32 *)xprth;
1da177e4
LT
225
226 fl->fl_ipsec_spi = ehdr[0];
227 }
228 break;
229
230 case IPPROTO_AH:
231 if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
4324a174 232 __be32 *ah_hdr = (__be32*)xprth;
1da177e4
LT
233
234 fl->fl_ipsec_spi = ah_hdr[1];
235 }
236 break;
237
238 case IPPROTO_COMP:
239 if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
4324a174 240 __be16 *ipcomp_hdr = (__be16 *)xprth;
1da177e4 241
4195f814 242 fl->fl_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
1da177e4
LT
243 }
244 break;
245 default:
246 fl->fl_ipsec_spi = 0;
247 break;
248 };
249 }
250 fl->proto = iph->protocol;
251 fl->fl4_dst = iph->daddr;
252 fl->fl4_src = iph->saddr;
4da3089f 253 fl->fl4_tos = iph->tos;
1da177e4
LT
254}
255
256static inline int xfrm4_garbage_collect(void)
257{
1da177e4 258 xfrm4_policy_afinfo.garbage_collect();
1da177e4
LT
259 return (atomic_read(&xfrm4_dst_ops.entries) > xfrm4_dst_ops.gc_thresh*2);
260}
261
262static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu)
263{
264 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
265 struct dst_entry *path = xdst->route;
266
267 path->ops->update_pmtu(path, mtu);
268}
269
aabc9761
HX
270static void xfrm4_dst_destroy(struct dst_entry *dst)
271{
272 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
273
274 if (likely(xdst->u.rt.idev))
275 in_dev_put(xdst->u.rt.idev);
276 xfrm_dst_destroy(xdst);
277}
278
279static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
280 int unregister)
281{
282 struct xfrm_dst *xdst;
283
284 if (!unregister)
285 return;
286
287 xdst = (struct xfrm_dst *)dst;
288 if (xdst->u.rt.idev->dev == dev) {
289 struct in_device *loopback_idev = in_dev_get(&loopback_dev);
290 BUG_ON(!loopback_idev);
291
292 do {
293 in_dev_put(xdst->u.rt.idev);
294 xdst->u.rt.idev = loopback_idev;
295 in_dev_hold(loopback_idev);
296 xdst = (struct xfrm_dst *)xdst->u.dst.child;
297 } while (xdst->u.dst.xfrm);
298
299 __in_dev_put(loopback_idev);
300 }
301
302 xfrm_dst_ifdown(dst, dev);
303}
304
1da177e4
LT
305static struct dst_ops xfrm4_dst_ops = {
306 .family = AF_INET,
307 .protocol = __constant_htons(ETH_P_IP),
308 .gc = xfrm4_garbage_collect,
309 .update_pmtu = xfrm4_update_pmtu,
aabc9761
HX
310 .destroy = xfrm4_dst_destroy,
311 .ifdown = xfrm4_dst_ifdown,
1da177e4
LT
312 .gc_thresh = 1024,
313 .entry_size = sizeof(struct xfrm_dst),
314};
315
316static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
317 .family = AF_INET,
1da177e4
LT
318 .dst_ops = &xfrm4_dst_ops,
319 .dst_lookup = xfrm4_dst_lookup,
a1e59abf 320 .get_saddr = xfrm4_get_saddr,
1da177e4
LT
321 .find_bundle = __xfrm4_find_bundle,
322 .bundle_create = __xfrm4_bundle_create,
323 .decode_session = _decode_session4,
324};
325
326static void __init xfrm4_policy_init(void)
327{
328 xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
329}
330
331static void __exit xfrm4_policy_fini(void)
332{
333 xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo);
334}
335
336void __init xfrm4_init(void)
337{
338 xfrm4_state_init();
339 xfrm4_policy_init();
340}
341