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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 fl4->flowi4_oif = skb_dst(skb)->dev->ifindex;
111
112 if (!ip_is_fragment(iph)) {
113 switch (iph->protocol) {
114 case IPPROTO_UDP:
115 case IPPROTO_UDPLITE:
116 case IPPROTO_TCP:
117 case IPPROTO_SCTP:
118 case IPPROTO_DCCP:
119 if (xprth + 4 < skb->data ||
120 pskb_may_pull(skb, xprth + 4 - skb->data)) {
121 __be16 *ports = (__be16 *)xprth;
122
123 fl4->fl4_sport = ports[!!reverse];
124 fl4->fl4_dport = ports[!reverse];
125 }
126 break;
127
128 case IPPROTO_ICMP:
129 if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
130 u8 *icmp = xprth;
131
132 fl4->fl4_icmp_type = icmp[0];
133 fl4->fl4_icmp_code = icmp[1];
134 }
135 break;
136
137 case IPPROTO_ESP:
138 if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
139 __be32 *ehdr = (__be32 *)xprth;
140
141 fl4->fl4_ipsec_spi = ehdr[0];
142 }
143 break;
144
145 case IPPROTO_AH:
146 if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
147 __be32 *ah_hdr = (__be32 *)xprth;
148
149 fl4->fl4_ipsec_spi = ah_hdr[1];
150 }
151 break;
152
153 case IPPROTO_COMP:
154 if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
155 __be16 *ipcomp_hdr = (__be16 *)xprth;
156
157 fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
158 }
159 break;
160
161 case IPPROTO_GRE:
162 if (pskb_may_pull(skb, xprth + 12 - skb->data)) {
163 __be16 *greflags = (__be16 *)xprth;
164 __be32 *gre_hdr = (__be32 *)xprth;
165
166 if (greflags[0] & GRE_KEY) {
167 if (greflags[0] & GRE_CSUM)
168 gre_hdr++;
169 fl4->fl4_gre_key = gre_hdr[1];
170 }
171 }
172 break;
173
174 default:
175 fl4->fl4_ipsec_spi = 0;
176 break;
177 }
178 }
179 fl4->flowi4_proto = iph->protocol;
180 fl4->daddr = reverse ? iph->saddr : iph->daddr;
181 fl4->saddr = reverse ? iph->daddr : iph->saddr;
182 fl4->flowi4_tos = iph->tos;
183}
184
185static inline int xfrm4_garbage_collect(struct dst_ops *ops)
186{
187 struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops);
188
189 xfrm4_policy_afinfo.garbage_collect(net);
190 return (dst_entries_get_slow(ops) > ops->gc_thresh * 2);
191}
192
193static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
194 struct sk_buff *skb, u32 mtu)
195{
196 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
197 struct dst_entry *path = xdst->route;
198
199 path->ops->update_pmtu(path, sk, skb, mtu);
200}
201
202static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
203 struct sk_buff *skb)
204{
205 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
206 struct dst_entry *path = xdst->route;
207
208 path->ops->redirect(path, sk, skb);
209}
210
211static void xfrm4_dst_destroy(struct dst_entry *dst)
212{
213 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
214
215 dst_destroy_metrics_generic(dst);
216
217 xfrm_dst_destroy(xdst);
218}
219
220static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
221 int unregister)
222{
223 if (!unregister)
224 return;
225
226 xfrm_dst_ifdown(dst, dev);
227}
228
229static struct dst_ops xfrm4_dst_ops = {
230 .family = AF_INET,
231 .protocol = cpu_to_be16(ETH_P_IP),
232 .gc = xfrm4_garbage_collect,
233 .update_pmtu = xfrm4_update_pmtu,
234 .redirect = xfrm4_redirect,
235 .cow_metrics = dst_cow_metrics_generic,
236 .destroy = xfrm4_dst_destroy,
237 .ifdown = xfrm4_dst_ifdown,
238 .local_out = __ip_local_out,
239 .gc_thresh = 1024,
240};
241
242static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
243 .family = AF_INET,
244 .dst_ops = &xfrm4_dst_ops,
245 .dst_lookup = xfrm4_dst_lookup,
246 .get_saddr = xfrm4_get_saddr,
247 .decode_session = _decode_session4,
248 .get_tos = xfrm4_get_tos,
249 .init_path = xfrm4_init_path,
250 .fill_dst = xfrm4_fill_dst,
251 .blackhole_route = ipv4_blackhole_route,
252};
253
254#ifdef CONFIG_SYSCTL
255static struct ctl_table xfrm4_policy_table[] = {
256 {
257 .procname = "xfrm4_gc_thresh",
258 .data = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
259 .maxlen = sizeof(int),
260 .mode = 0644,
261 .proc_handler = proc_dointvec,
262 },
263 { }
264};
265
266static int __net_init xfrm4_net_init(struct net *net)
267{
268 struct ctl_table *table;
269 struct ctl_table_header *hdr;
270
271 table = xfrm4_policy_table;
272 if (!net_eq(net, &init_net)) {
273 table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
274 if (!table)
275 goto err_alloc;
276
277 table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
278 }
279
280 hdr = register_net_sysctl(net, "net/ipv4", table);
281 if (!hdr)
282 goto err_reg;
283
284 net->ipv4.xfrm4_hdr = hdr;
285 return 0;
286
287err_reg:
288 if (!net_eq(net, &init_net))
289 kfree(table);
290err_alloc:
291 return -ENOMEM;
292}
293
294static void __net_exit xfrm4_net_exit(struct net *net)
295{
296 struct ctl_table *table;
297
298 if (net->ipv4.xfrm4_hdr == NULL)
299 return;
300
301 table = net->ipv4.xfrm4_hdr->ctl_table_arg;
302 unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
303 if (!net_eq(net, &init_net))
304 kfree(table);
305}
306
307static struct pernet_operations __net_initdata xfrm4_net_ops = {
308 .init = xfrm4_net_init,
309 .exit = xfrm4_net_exit,
310};
311#endif
312
313static void __init xfrm4_policy_init(void)
314{
315 xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
316}
317
318void __init xfrm4_init(void)
319{
320 dst_entries_init(&xfrm4_dst_ops);
321
322 xfrm4_state_init();
323 xfrm4_policy_init();
324#ifdef CONFIG_SYSCTL
325 register_pernet_subsys(&xfrm4_net_ops);
326#endif
327}
328
329
