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11#include <linux/err.h>
12#include <linux/kernel.h>
13#include <linux/inetdevice.h>
14#include <linux/if_tunnel.h>
15#include <net/dst.h>
16#include <net/xfrm.h>
17#include <net/ip.h>
18
19static struct xfrm_policy_afinfo xfrm4_policy_afinfo;
20
21static struct dst_entry *__xfrm4_dst_lookup(struct net *net, struct flowi4 *fl4,
22 int tos,
23 const xfrm_address_t *saddr,
24 const xfrm_address_t *daddr)
25{
26 struct rtable *rt;
27
28 memset(fl4, 0, sizeof(*fl4));
29 fl4->daddr = daddr->a4;
30 fl4->flowi4_tos = tos;
31 if (saddr)
32 fl4->saddr = saddr->a4;
33
34 rt = __ip_route_output_key(net, fl4);
35 if (!IS_ERR(rt))
36 return &rt->dst;
37
38 return ERR_CAST(rt);
39}
40
41static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos,
42 const xfrm_address_t *saddr,
43 const xfrm_address_t *daddr)
44{
45 struct flowi4 fl4;
46
47 return __xfrm4_dst_lookup(net, &fl4, tos, saddr, daddr);
48}
49
50static int xfrm4_get_saddr(struct net *net,
51 xfrm_address_t *saddr, xfrm_address_t *daddr)
52{
53 struct dst_entry *dst;
54 struct flowi4 fl4;
55
56 dst = __xfrm4_dst_lookup(net, &fl4, 0, NULL, daddr);
57 if (IS_ERR(dst))
58 return -EHOSTUNREACH;
59
60 saddr->a4 = fl4.saddr;
61 dst_release(dst);
62 return 0;
63}
64
65static int xfrm4_get_tos(const struct flowi *fl)
66{
67 return IPTOS_RT_MASK & fl->u.ip4.flowi4_tos;
68}
69
70static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst,
71 int nfheader_len)
72{
73 return 0;
74}
75
76static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
77 const struct flowi *fl)
78{
79 struct rtable *rt = (struct rtable *)xdst->route;
80 const struct flowi4 *fl4 = &fl->u.ip4;
81
82 xdst->u.rt.rt_iif = fl4->flowi4_iif;
83
84 xdst->u.dst.dev = dev;
85 dev_hold(dev);
86
87
88
89 xdst->u.rt.rt_is_input = rt->rt_is_input;
90 xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
91 RTCF_LOCAL);
92 xdst->u.rt.rt_type = rt->rt_type;
93 xdst->u.rt.rt_gateway = rt->rt_gateway;
94 xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway;
95 xdst->u.rt.rt_pmtu = rt->rt_pmtu;
96 INIT_LIST_HEAD(&xdst->u.rt.rt_uncached);
97
98 return 0;
99}
100
101static void
102_decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
103{
104 const struct iphdr *iph = ip_hdr(skb);
105 u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
106 struct flowi4 *fl4 = &fl->u.ip4;
107
108 memset(fl4, 0, sizeof(struct flowi4));
109 fl4->flowi4_mark = skb->mark;
110
111 if (!ip_is_fragment(iph)) {
112 switch (iph->protocol) {
113 case IPPROTO_UDP:
114 case IPPROTO_UDPLITE:
115 case IPPROTO_TCP:
116 case IPPROTO_SCTP:
117 case IPPROTO_DCCP:
118 if (xprth + 4 < skb->data ||
119 pskb_may_pull(skb, xprth + 4 - skb->data)) {
120 __be16 *ports = (__be16 *)xprth;
121
122 fl4->fl4_sport = ports[!!reverse];
123 fl4->fl4_dport = ports[!reverse];
124 }
125 break;
126
127 case IPPROTO_ICMP:
128 if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
129 u8 *icmp = xprth;
130
131 fl4->fl4_icmp_type = icmp[0];
132 fl4->fl4_icmp_code = icmp[1];
133 }
134 break;
135
136 case IPPROTO_ESP:
137 if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
138 __be32 *ehdr = (__be32 *)xprth;
139
140 fl4->fl4_ipsec_spi = ehdr[0];
141 }
142 break;
143
144 case IPPROTO_AH:
145 if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
146 __be32 *ah_hdr = (__be32 *)xprth;
147
148 fl4->fl4_ipsec_spi = ah_hdr[1];
149 }
150 break;
151
152 case IPPROTO_COMP:
153 if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
154 __be16 *ipcomp_hdr = (__be16 *)xprth;
155
156 fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
157 }
158 break;
159
160 case IPPROTO_GRE:
161 if (pskb_may_pull(skb, xprth + 12 - skb->data)) {
162 __be16 *greflags = (__be16 *)xprth;
163 __be32 *gre_hdr = (__be32 *)xprth;
164
165 if (greflags[0] & GRE_KEY) {
166 if (greflags[0] & GRE_CSUM)
167 gre_hdr++;
168 fl4->fl4_gre_key = gre_hdr[1];
169 }
170 }
171 break;
172
173 default:
174 fl4->fl4_ipsec_spi = 0;
175 break;
176 }
177 }
178 fl4->flowi4_proto = iph->protocol;
179 fl4->daddr = reverse ? iph->saddr : iph->daddr;
180 fl4->saddr = reverse ? iph->daddr : iph->saddr;
181 fl4->flowi4_tos = iph->tos;
182}
183
184static inline int xfrm4_garbage_collect(struct dst_ops *ops)
185{
186 struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops);
187
188 xfrm4_policy_afinfo.garbage_collect(net);
189 return (dst_entries_get_slow(ops) > ops->gc_thresh * 2);
190}
191
192static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
193 struct sk_buff *skb, u32 mtu)
194{
195 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
196 struct dst_entry *path = xdst->route;
197
198 path->ops->update_pmtu(path, sk, skb, mtu);
199}
200
201static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
202 struct sk_buff *skb)
203{
204 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
205 struct dst_entry *path = xdst->route;
206
207 path->ops->redirect(path, sk, skb);
208}
209
210static void xfrm4_dst_destroy(struct dst_entry *dst)
211{
212 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
213
214 dst_destroy_metrics_generic(dst);
215
216 xfrm_dst_destroy(xdst);
217}
218
219static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
220 int unregister)
221{
222 if (!unregister)
223 return;
224
225 xfrm_dst_ifdown(dst, dev);
226}
227
228static struct dst_ops xfrm4_dst_ops = {
229 .family = AF_INET,
230 .protocol = cpu_to_be16(ETH_P_IP),
231 .gc = xfrm4_garbage_collect,
232 .update_pmtu = xfrm4_update_pmtu,
233 .redirect = xfrm4_redirect,
234 .cow_metrics = dst_cow_metrics_generic,
235 .destroy = xfrm4_dst_destroy,
236 .ifdown = xfrm4_dst_ifdown,
237 .local_out = __ip_local_out,
238 .gc_thresh = 1024,
239};
240
241static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
242 .family = AF_INET,
243 .dst_ops = &xfrm4_dst_ops,
244 .dst_lookup = xfrm4_dst_lookup,
245 .get_saddr = xfrm4_get_saddr,
246 .decode_session = _decode_session4,
247 .get_tos = xfrm4_get_tos,
248 .init_path = xfrm4_init_path,
249 .fill_dst = xfrm4_fill_dst,
250 .blackhole_route = ipv4_blackhole_route,
251};
252
253#ifdef CONFIG_SYSCTL
254static struct ctl_table xfrm4_policy_table[] = {
255 {
256 .procname = "xfrm4_gc_thresh",
257 .data = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
258 .maxlen = sizeof(int),
259 .mode = 0644,
260 .proc_handler = proc_dointvec,
261 },
262 { }
263};
264
265static int __net_init xfrm4_net_init(struct net *net)
266{
267 struct ctl_table *table;
268 struct ctl_table_header *hdr;
269
270 table = xfrm4_policy_table;
271 if (!net_eq(net, &init_net)) {
272 table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
273 if (!table)
274 goto err_alloc;
275
276 table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
277 }
278
279 hdr = register_net_sysctl(net, "net/ipv4", table);
280 if (!hdr)
281 goto err_reg;
282
283 net->ipv4.xfrm4_hdr = hdr;
284 return 0;
285
286err_reg:
287 if (!net_eq(net, &init_net))
288 kfree(table);
289err_alloc:
290 return -ENOMEM;
291}
292
293static void __net_exit xfrm4_net_exit(struct net *net)
294{
295 struct ctl_table *table;
296
297 if (net->ipv4.xfrm4_hdr == NULL)
298 return;
299
300 table = net->ipv4.xfrm4_hdr->ctl_table_arg;
301 unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
302 if (!net_eq(net, &init_net))
303 kfree(table);
304}
305
306static struct pernet_operations __net_initdata xfrm4_net_ops = {
307 .init = xfrm4_net_init,
308 .exit = xfrm4_net_exit,
309};
310#endif
311
312static void __init xfrm4_policy_init(void)
313{
314 xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
315}
316
317void __init xfrm4_init(void)
318{
319 dst_entries_init(&xfrm4_dst_ops);
320
321 xfrm4_state_init();
322 xfrm4_policy_init();
323#ifdef CONFIG_SYSCTL
324 register_pernet_subsys(&xfrm4_net_ops);
325#endif
326}
327
328
