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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 int oif = 0;
108
109 if (skb_dst(skb))
110 oif = skb_dst(skb)->dev->ifindex;
111
112 memset(fl4, 0, sizeof(struct flowi4));
113 fl4->flowi4_mark = skb->mark;
114 fl4->flowi4_oif = reverse ? skb->skb_iif : oif;
115
116 if (!ip_is_fragment(iph)) {
117 switch (iph->protocol) {
118 case IPPROTO_UDP:
119 case IPPROTO_UDPLITE:
120 case IPPROTO_TCP:
121 case IPPROTO_SCTP:
122 case IPPROTO_DCCP:
123 if (xprth + 4 < skb->data ||
124 pskb_may_pull(skb, xprth + 4 - skb->data)) {
125 __be16 *ports = (__be16 *)xprth;
126
127 fl4->fl4_sport = ports[!!reverse];
128 fl4->fl4_dport = ports[!reverse];
129 }
130 break;
131
132 case IPPROTO_ICMP:
133 if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
134 u8 *icmp = xprth;
135
136 fl4->fl4_icmp_type = icmp[0];
137 fl4->fl4_icmp_code = icmp[1];
138 }
139 break;
140
141 case IPPROTO_ESP:
142 if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
143 __be32 *ehdr = (__be32 *)xprth;
144
145 fl4->fl4_ipsec_spi = ehdr[0];
146 }
147 break;
148
149 case IPPROTO_AH:
150 if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
151 __be32 *ah_hdr = (__be32 *)xprth;
152
153 fl4->fl4_ipsec_spi = ah_hdr[1];
154 }
155 break;
156
157 case IPPROTO_COMP:
158 if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
159 __be16 *ipcomp_hdr = (__be16 *)xprth;
160
161 fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
162 }
163 break;
164
165 case IPPROTO_GRE:
166 if (pskb_may_pull(skb, xprth + 12 - skb->data)) {
167 __be16 *greflags = (__be16 *)xprth;
168 __be32 *gre_hdr = (__be32 *)xprth;
169
170 if (greflags[0] & GRE_KEY) {
171 if (greflags[0] & GRE_CSUM)
172 gre_hdr++;
173 fl4->fl4_gre_key = gre_hdr[1];
174 }
175 }
176 break;
177
178 default:
179 fl4->fl4_ipsec_spi = 0;
180 break;
181 }
182 }
183 fl4->flowi4_proto = iph->protocol;
184 fl4->daddr = reverse ? iph->saddr : iph->daddr;
185 fl4->saddr = reverse ? iph->daddr : iph->saddr;
186 fl4->flowi4_tos = iph->tos;
187}
188
189static inline int xfrm4_garbage_collect(struct dst_ops *ops)
190{
191 struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops);
192
193 xfrm4_policy_afinfo.garbage_collect(net);
194 return (dst_entries_get_slow(ops) > ops->gc_thresh * 2);
195}
196
197static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
198 struct sk_buff *skb, u32 mtu)
199{
200 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
201 struct dst_entry *path = xdst->route;
202
203 path->ops->update_pmtu(path, sk, skb, mtu);
204}
205
206static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
207 struct sk_buff *skb)
208{
209 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
210 struct dst_entry *path = xdst->route;
211
212 path->ops->redirect(path, sk, skb);
213}
214
215static void xfrm4_dst_destroy(struct dst_entry *dst)
216{
217 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
218
219 dst_destroy_metrics_generic(dst);
220
221 xfrm_dst_destroy(xdst);
222}
223
224static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
225 int unregister)
226{
227 if (!unregister)
228 return;
229
230 xfrm_dst_ifdown(dst, dev);
231}
232
233static struct dst_ops xfrm4_dst_ops = {
234 .family = AF_INET,
235 .gc = xfrm4_garbage_collect,
236 .update_pmtu = xfrm4_update_pmtu,
237 .redirect = xfrm4_redirect,
238 .cow_metrics = dst_cow_metrics_generic,
239 .destroy = xfrm4_dst_destroy,
240 .ifdown = xfrm4_dst_ifdown,
241 .local_out = __ip_local_out,
242 .gc_thresh = 32768,
243};
244
245static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
246 .family = AF_INET,
247 .dst_ops = &xfrm4_dst_ops,
248 .dst_lookup = xfrm4_dst_lookup,
249 .get_saddr = xfrm4_get_saddr,
250 .decode_session = _decode_session4,
251 .get_tos = xfrm4_get_tos,
252 .init_path = xfrm4_init_path,
253 .fill_dst = xfrm4_fill_dst,
254 .blackhole_route = ipv4_blackhole_route,
255};
256
257#ifdef CONFIG_SYSCTL
258static struct ctl_table xfrm4_policy_table[] = {
259 {
260 .procname = "xfrm4_gc_thresh",
261 .data = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
262 .maxlen = sizeof(int),
263 .mode = 0644,
264 .proc_handler = proc_dointvec,
265 },
266 { }
267};
268
269static int __net_init xfrm4_net_init(struct net *net)
270{
271 struct ctl_table *table;
272 struct ctl_table_header *hdr;
273
274 table = xfrm4_policy_table;
275 if (!net_eq(net, &init_net)) {
276 table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
277 if (!table)
278 goto err_alloc;
279
280 table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
281 }
282
283 hdr = register_net_sysctl(net, "net/ipv4", table);
284 if (!hdr)
285 goto err_reg;
286
287 net->ipv4.xfrm4_hdr = hdr;
288 return 0;
289
290err_reg:
291 if (!net_eq(net, &init_net))
292 kfree(table);
293err_alloc:
294 return -ENOMEM;
295}
296
297static void __net_exit xfrm4_net_exit(struct net *net)
298{
299 struct ctl_table *table;
300
301 if (!net->ipv4.xfrm4_hdr)
302 return;
303
304 table = net->ipv4.xfrm4_hdr->ctl_table_arg;
305 unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
306 if (!net_eq(net, &init_net))
307 kfree(table);
308}
309
310static struct pernet_operations __net_initdata xfrm4_net_ops = {
311 .init = xfrm4_net_init,
312 .exit = xfrm4_net_exit,
313};
314#endif
315
316static void __init xfrm4_policy_init(void)
317{
318 xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
319}
320
321void __init xfrm4_init(void)
322{
323 dst_entries_init(&xfrm4_dst_ops);
324
325 xfrm4_state_init();
326 xfrm4_policy_init();
327 xfrm4_protocol_init();
328#ifdef CONFIG_SYSCTL
329 register_pernet_subsys(&xfrm4_net_ops);
330#endif
331}
332
333
