1 /*
2 * xfrm6_policy.c: based on xfrm4_policy.c
3 *
4 * Authors:
5 * Mitsuru KANDA @USAGI
6 * Kazunori MIYAZAWA @USAGI
7 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
8 * IPv6 support
9 * YOSHIFUJI Hideaki
10 * Split up af-specific portion
11 *
12 */
13
14 #include <linux/err.h>
15 #include <linux/kernel.h>
16 #include <linux/netdevice.h>
17 #include <net/addrconf.h>
18 #include <net/dst.h>
19 #include <net/xfrm.h>
20 #include <net/ip.h>
21 #include <net/ipv6.h>
22 #include <net/ip6_route.h>
23 #if IS_ENABLED(CONFIG_IPV6_MIP6)
24 #include <net/mip6.h>
25 #endif
26
27 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
28
29 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos,
30 const xfrm_address_t *saddr,
31 const xfrm_address_t *daddr)
32 {
33 struct flowi6 fl6;
34 struct dst_entry *dst;
35 int err;
36
37 memset(&fl6, 0, sizeof(fl6));
38 memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr));
39 if (saddr)
40 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr));
41
42 dst = ip6_route_output(net, NULL, &fl6);
43
44 err = dst->error;
45 if (dst->error) {
46 dst_release(dst);
47 dst = ERR_PTR(err);
48 }
49
50 return dst;
51 }
52
53 static int xfrm6_get_saddr(struct net *net,
54 xfrm_address_t *saddr, xfrm_address_t *daddr)
55 {
56 struct dst_entry *dst;
57 struct net_device *dev;
58
59 dst = xfrm6_dst_lookup(net, 0, NULL, daddr);
60 if (IS_ERR(dst))
61 return -EHOSTUNREACH;
62
63 dev = ip6_dst_idev(dst)->dev;
64 ipv6_dev_get_saddr(dev_net(dev), dev,
65 (struct in6_addr *)&daddr->a6, 0,
66 (struct in6_addr *)&saddr->a6);
67 dst_release(dst);
68 return 0;
69 }
70
71 static int xfrm6_get_tos(const struct flowi *fl)
72 {
73 return 0;
74 }
75
76 static void xfrm6_init_dst(struct net *net, struct xfrm_dst *xdst)
77 {
78 struct rt6_info *rt = (struct rt6_info *)xdst;
79
80 rt6_init_peer(rt, net->ipv6.peers);
81 }
82
83 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
84 int nfheader_len)
85 {
86 if (dst->ops->family == AF_INET6) {
87 struct rt6_info *rt = (struct rt6_info*)dst;
88 if (rt->rt6i_node)
89 path->path_cookie = rt->rt6i_node->fn_sernum;
90 }
91
92 path->u.rt6.rt6i_nfheader_len = nfheader_len;
93
94 return 0;
95 }
96
97 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
98 const struct flowi *fl)
99 {
100 struct rt6_info *rt = (struct rt6_info*)xdst->route;
101
102 xdst->u.dst.dev = dev;
103 dev_hold(dev);
104
105 xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
106 if (!xdst->u.rt6.rt6i_idev) {
107 dev_put(dev);
108 return -ENODEV;
109 }
110
111 rt6_transfer_peer(&xdst->u.rt6, rt);
112
113 /* Sheit... I remember I did this right. Apparently,
114 * it was magically lost, so this code needs audit */
115 xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
116 RTF_LOCAL);
117 xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
118 xdst->u.rt6.rt6i_node = rt->rt6i_node;
119 if (rt->rt6i_node)
120 xdst->route_cookie = rt->rt6i_node->fn_sernum;
121 xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
122 xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
123 xdst->u.rt6.rt6i_src = rt->rt6i_src;
124
125 return 0;
126 }
127
128 static inline void
129 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
130 {
131 struct flowi6 *fl6 = &fl->u.ip6;
132 int onlyproto = 0;
133 u16 offset = skb_network_header_len(skb);
134 const struct ipv6hdr *hdr = ipv6_hdr(skb);
135 struct ipv6_opt_hdr *exthdr;
136 const unsigned char *nh = skb_network_header(skb);
137 u8 nexthdr = nh[IP6CB(skb)->nhoff];
138
139 memset(fl6, 0, sizeof(struct flowi6));
140 fl6->flowi6_mark = skb->mark;
141
142 fl6->daddr = reverse ? hdr->saddr : hdr->daddr;
143 fl6->saddr = reverse ? hdr->daddr : hdr->saddr;
144
145 while (nh + offset + 1 < skb->data ||
146 pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
147 nh = skb_network_header(skb);
148 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
149
150 switch (nexthdr) {
151 case NEXTHDR_FRAGMENT:
152 onlyproto = 1;
153 case NEXTHDR_ROUTING:
154 case NEXTHDR_HOP:
155 case NEXTHDR_DEST:
156 offset += ipv6_optlen(exthdr);
157 nexthdr = exthdr->nexthdr;
158 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
159 break;
160
161 case IPPROTO_UDP:
162 case IPPROTO_UDPLITE:
163 case IPPROTO_TCP:
164 case IPPROTO_SCTP:
165 case IPPROTO_DCCP:
166 if (!onlyproto && (nh + offset + 4 < skb->data ||
167 pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
168 __be16 *ports = (__be16 *)exthdr;
169
170 fl6->fl6_sport = ports[!!reverse];
171 fl6->fl6_dport = ports[!reverse];
172 }
173 fl6->flowi6_proto = nexthdr;
174 return;
175
176 case IPPROTO_ICMPV6:
177 if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
178 u8 *icmp = (u8 *)exthdr;
179
180 fl6->fl6_icmp_type = icmp[0];
181 fl6->fl6_icmp_code = icmp[1];
182 }
183 fl6->flowi6_proto = nexthdr;
184 return;
185
186 #if IS_ENABLED(CONFIG_IPV6_MIP6)
187 case IPPROTO_MH:
188 if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
189 struct ip6_mh *mh;
190 mh = (struct ip6_mh *)exthdr;
191
192 fl6->fl6_mh_type = mh->ip6mh_type;
193 }
194 fl6->flowi6_proto = nexthdr;
195 return;
196 #endif
197
198 /* XXX Why are there these headers? */
199 case IPPROTO_AH:
200 case IPPROTO_ESP:
201 case IPPROTO_COMP:
202 default:
203 fl6->fl6_ipsec_spi = 0;
204 fl6->flowi6_proto = nexthdr;
205 return;
206 }
207 }
208 }
209
210 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
211 {
212 struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
213
214 xfrm6_policy_afinfo.garbage_collect(net);
215 return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
216 }
217
218 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
219 struct sk_buff *skb, u32 mtu)
220 {
221 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
222 struct dst_entry *path = xdst->route;
223
224 path->ops->update_pmtu(path, sk, skb, mtu);
225 }
226
227 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
228 struct sk_buff *skb)
229 {
230 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
231 struct dst_entry *path = xdst->route;
232
233 path->ops->redirect(path, sk, skb);
234 }
235
236 static void xfrm6_dst_destroy(struct dst_entry *dst)
237 {
238 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
239
240 if (likely(xdst->u.rt6.rt6i_idev))
241 in6_dev_put(xdst->u.rt6.rt6i_idev);
242 dst_destroy_metrics_generic(dst);
243 if (rt6_has_peer(&xdst->u.rt6)) {
244 struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6);
245 inet_putpeer(peer);
246 }
247 xfrm_dst_destroy(xdst);
248 }
249
250 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
251 int unregister)
252 {
253 struct xfrm_dst *xdst;
254
255 if (!unregister)
256 return;
257
258 xdst = (struct xfrm_dst *)dst;
259 if (xdst->u.rt6.rt6i_idev->dev == dev) {
260 struct inet6_dev *loopback_idev =
261 in6_dev_get(dev_net(dev)->loopback_dev);
262 BUG_ON(!loopback_idev);
263
264 do {
265 in6_dev_put(xdst->u.rt6.rt6i_idev);
266 xdst->u.rt6.rt6i_idev = loopback_idev;
267 in6_dev_hold(loopback_idev);
268 xdst = (struct xfrm_dst *)xdst->u.dst.child;
269 } while (xdst->u.dst.xfrm);
270
271 __in6_dev_put(loopback_idev);
272 }
273
274 xfrm_dst_ifdown(dst, dev);
275 }
276
277 static struct dst_ops xfrm6_dst_ops = {
278 .family = AF_INET6,
279 .protocol = cpu_to_be16(ETH_P_IPV6),
280 .gc = xfrm6_garbage_collect,
281 .update_pmtu = xfrm6_update_pmtu,
282 .redirect = xfrm6_redirect,
283 .cow_metrics = dst_cow_metrics_generic,
284 .destroy = xfrm6_dst_destroy,
285 .ifdown = xfrm6_dst_ifdown,
286 .local_out = __ip6_local_out,
287 .gc_thresh = 32768,
288 };
289
290 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
291 .family = AF_INET6,
292 .dst_ops = &xfrm6_dst_ops,
293 .dst_lookup = xfrm6_dst_lookup,
294 .get_saddr = xfrm6_get_saddr,
295 .decode_session = _decode_session6,
296 .get_tos = xfrm6_get_tos,
297 .init_dst = xfrm6_init_dst,
298 .init_path = xfrm6_init_path,
299 .fill_dst = xfrm6_fill_dst,
300 .blackhole_route = ip6_blackhole_route,
301 };
302
303 static int __init xfrm6_policy_init(void)
304 {
305 return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
306 }
307
308 static void xfrm6_policy_fini(void)
309 {
310 xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
311 }
312
313 #ifdef CONFIG_SYSCTL
314 static struct ctl_table xfrm6_policy_table[] = {
315 {
316 .procname = "xfrm6_gc_thresh",
317 .data = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
318 .maxlen = sizeof(int),
319 .mode = 0644,
320 .proc_handler = proc_dointvec,
321 },
322 { }
323 };
324
325 static int __net_init xfrm6_net_init(struct net *net)
326 {
327 struct ctl_table *table;
328 struct ctl_table_header *hdr;
329
330 table = xfrm6_policy_table;
331 if (!net_eq(net, &init_net)) {
332 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL);
333 if (!table)
334 goto err_alloc;
335
336 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh;
337 }
338
339 hdr = register_net_sysctl(net, "net/ipv6", table);
340 if (!hdr)
341 goto err_reg;
342
343 net->ipv6.sysctl.xfrm6_hdr = hdr;
344 return 0;
345
346 err_reg:
347 if (!net_eq(net, &init_net))
348 kfree(table);
349 err_alloc:
350 return -ENOMEM;
351 }
352
353 static void __net_exit xfrm6_net_exit(struct net *net)
354 {
355 struct ctl_table *table;
356
357 if (net->ipv6.sysctl.xfrm6_hdr == NULL)
358 return;
359
360 table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg;
361 unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr);
362 if (!net_eq(net, &init_net))
363 kfree(table);
364 }
365
366 static struct pernet_operations xfrm6_net_ops = {
367 .init = xfrm6_net_init,
368 .exit = xfrm6_net_exit,
369 };
370 #endif
371
372 int __init xfrm6_init(void)
373 {
374 int ret;
375
376 dst_entries_init(&xfrm6_dst_ops);
377
378 ret = xfrm6_policy_init();
379 if (ret) {
380 dst_entries_destroy(&xfrm6_dst_ops);
381 goto out;
382 }
383 ret = xfrm6_state_init();
384 if (ret)
385 goto out_policy;
386
387 #ifdef CONFIG_SYSCTL
388 register_pernet_subsys(&xfrm6_net_ops);
389 #endif
390 out:
391 return ret;
392 out_policy:
393 xfrm6_policy_fini();
394 goto out;
395 }
396
397 void xfrm6_fini(void)
398 {
399 #ifdef CONFIG_SYSCTL
400 unregister_pernet_subsys(&xfrm6_net_ops);
401 #endif
402 xfrm6_policy_fini();
403 xfrm6_state_fini();
404 dst_entries_destroy(&xfrm6_dst_ops);
405 }
406
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