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YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * xfrm4_policy.c
3 *
4 * Changes:
5 * Kazunori MIYAZAWA @USAGI
6 * YOSHIFUJI Hideaki @USAGI
7 * Split up af-specific portion
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09008 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 */
10
Herbert Xu66cdb3c2007-11-13 21:37:28 -080011#include <linux/err.h>
12#include <linux/kernel.h>
Herbert Xuaabc9762005-05-03 16:27:10 -070013#include <linux/inetdevice.h>
Timo Teräscc9ff192010-11-03 04:41:38 +000014#include <linux/if_tunnel.h>
Herbert Xu45ff5a32007-11-13 21:35:32 -080015#include <net/dst.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <net/xfrm.h>
17#include <net/ip.h>
18
Linus Torvalds1da177e2005-04-16 15:20:36 -070019static struct xfrm_policy_afinfo xfrm4_policy_afinfo;
20
David S. Miller8f01cb02011-05-09 15:13:28 -070021static 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)
Linus Torvalds1da177e2005-04-16 15:20:36 -070025{
Herbert Xu66cdb3c2007-11-13 21:37:28 -080026 struct rtable *rt;
Patrick McHardya1e59ab2006-09-19 12:57:34 -070027
David S. Miller8f01cb02011-05-09 15:13:28 -070028 memset(fl4, 0, sizeof(*fl4));
29 fl4->daddr = daddr->a4;
30 fl4->flowi4_tos = tos;
Herbert Xu66cdb3c2007-11-13 21:37:28 -080031 if (saddr)
David S. Miller8f01cb02011-05-09 15:13:28 -070032 fl4->saddr = saddr->a4;
Herbert Xu66cdb3c2007-11-13 21:37:28 -080033
David S. Miller8f01cb02011-05-09 15:13:28 -070034 rt = __ip_route_output_key(net, fl4);
David S. Millerb23dd4f2011-03-02 14:31:35 -080035 if (!IS_ERR(rt))
36 return &rt->dst;
37
38 return ERR_CAST(rt);
Herbert Xu66cdb3c2007-11-13 21:37:28 -080039}
40
David S. Miller8f01cb02011-05-09 15:13:28 -070041static 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
Alexey Dobriyanfbda33b2008-11-25 17:56:49 -080050static int xfrm4_get_saddr(struct net *net,
51 xfrm_address_t *saddr, xfrm_address_t *daddr)
Herbert Xu66cdb3c2007-11-13 21:37:28 -080052{
53 struct dst_entry *dst;
David S. Miller8f01cb02011-05-09 15:13:28 -070054 struct flowi4 fl4;
Herbert Xu66cdb3c2007-11-13 21:37:28 -080055
David S. Miller8f01cb02011-05-09 15:13:28 -070056 dst = __xfrm4_dst_lookup(net, &fl4, 0, NULL, daddr);
Herbert Xu66cdb3c2007-11-13 21:37:28 -080057 if (IS_ERR(dst))
58 return -EHOSTUNREACH;
59
David S. Miller8f01cb02011-05-09 15:13:28 -070060 saddr->a4 = fl4.saddr;
Herbert Xu66cdb3c2007-11-13 21:37:28 -080061 dst_release(dst);
62 return 0;
Patrick McHardya1e59ab2006-09-19 12:57:34 -070063}
64
David S. Miller05d84022011-02-22 17:47:10 -080065static int xfrm4_get_tos(const struct flowi *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -070066{
David S. Miller7e1dc7b2011-03-12 02:42:11 -050067 return IPTOS_RT_MASK & fl->u.ip4.flowi4_tos; /* Strip ECN bits */
Herbert Xu25ee3282007-12-11 09:32:34 -080068}
Linus Torvalds1da177e2005-04-16 15:20:36 -070069
Masahide NAKAMURAa1b05142007-12-20 20:41:12 -080070static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst,
71 int nfheader_len)
72{
73 return 0;
74}
75
Herbert Xu87c1e122010-03-02 02:51:56 +000076static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
David S. Miller0c7b3ee2011-02-22 17:48:57 -080077 const struct flowi *fl)
Herbert Xu25ee3282007-12-11 09:32:34 -080078{
79 struct rtable *rt = (struct rtable *)xdst->route;
David S. Miller7e1dc7b2011-03-12 02:42:11 -050080 const struct flowi4 *fl4 = &fl->u.ip4;
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
Yan, Zhengb7323392011-10-22 21:58:20 +000082 xdst->u.rt.rt_iif = fl4->flowi4_iif;
Linus Torvalds1da177e2005-04-16 15:20:36 -070083
Herbert Xu25ee3282007-12-11 09:32:34 -080084 xdst->u.dst.dev = dev;
85 dev_hold(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
Herbert Xu25ee3282007-12-11 09:32:34 -080087 /* Sheit... I remember I did this right. Apparently,
88 * it was magically lost, so this code needs audit */
David S. Miller9917e1e82012-07-17 14:44:26 -070089 xdst->u.rt.rt_is_input = rt->rt_is_input;
Herbert Xu25ee3282007-12-11 09:32:34 -080090 xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
91 RTCF_LOCAL);
92 xdst->u.rt.rt_type = rt->rt_type;
Herbert Xu25ee3282007-12-11 09:32:34 -080093 xdst->u.rt.rt_gateway = rt->rt_gateway;
Julian Anastasov155e8332012-10-08 11:41:18 +000094 xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway;
David S. Miller59436342012-07-10 06:58:42 -070095 xdst->u.rt.rt_pmtu = rt->rt_pmtu;
David S. Millercaacf052012-07-31 15:06:50 -070096 INIT_LIST_HEAD(&xdst->u.rt.rt_uncached);
Miika Komu43372262007-02-06 14:27:32 -080097
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070099}
100
101static void
Herbert Xud5422ef2007-12-12 10:44:16 -0800102_decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103{
Eric Dumazetb71d1d42011-04-22 04:53:02 +0000104 const struct iphdr *iph = ip_hdr(skb);
Arnaldo Carvalho de Melod56f90a2007-04-10 20:50:43 -0700105 u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
David S. Miller7e1dc7b2011-03-12 02:42:11 -0500106 struct flowi4 *fl4 = &fl->u.ip4;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107
David S. Miller7e1dc7b2011-03-12 02:42:11 -0500108 memset(fl4, 0, sizeof(struct flowi4));
109 fl4->flowi4_mark = skb->mark;
Peter Kosyh44b451f2010-07-02 07:47:55 +0000110
Paul Gortmaker56f8a752011-06-21 20:33:34 -0700111 if (!ip_is_fragment(iph)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 switch (iph->protocol) {
113 case IPPROTO_UDP:
Gerrit Renkerba4e58e2006-11-27 11:10:57 -0800114 case IPPROTO_UDPLITE:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 case IPPROTO_TCP:
116 case IPPROTO_SCTP:
Patrick McHardy9e999992005-12-19 14:03:46 -0800117 case IPPROTO_DCCP:
Wei Yongjunc615c9f2009-07-02 16:57:23 +0000118 if (xprth + 4 < skb->data ||
119 pskb_may_pull(skb, xprth + 4 - skb->data)) {
Al Viro8c689a62006-11-08 00:20:21 -0800120 __be16 *ports = (__be16 *)xprth;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121
David S. Miller9cce96d2011-03-12 03:00:33 -0500122 fl4->fl4_sport = ports[!!reverse];
123 fl4->fl4_dport = ports[!reverse];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 }
125 break;
126
127 case IPPROTO_ICMP:
128 if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
129 u8 *icmp = xprth;
130
David S. Miller9cce96d2011-03-12 03:00:33 -0500131 fl4->fl4_icmp_type = icmp[0];
132 fl4->fl4_icmp_code = icmp[1];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 }
134 break;
135
136 case IPPROTO_ESP:
137 if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
Al Viro4324a172006-09-27 18:49:07 -0700138 __be32 *ehdr = (__be32 *)xprth;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139
David S. Miller9cce96d2011-03-12 03:00:33 -0500140 fl4->fl4_ipsec_spi = ehdr[0];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 }
142 break;
143
144 case IPPROTO_AH:
145 if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
Daniel Baluta5e73ea12012-04-15 01:34:41 +0000146 __be32 *ah_hdr = (__be32 *)xprth;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147
David S. Miller9cce96d2011-03-12 03:00:33 -0500148 fl4->fl4_ipsec_spi = ah_hdr[1];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 }
150 break;
151
152 case IPPROTO_COMP:
153 if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
Al Viro4324a172006-09-27 18:49:07 -0700154 __be16 *ipcomp_hdr = (__be16 *)xprth;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
David S. Miller9cce96d2011-03-12 03:00:33 -0500156 fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 }
158 break;
Timo Teräscc9ff192010-11-03 04:41:38 +0000159
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++;
David S. Miller9cce96d2011-03-12 03:00:33 -0500168 fl4->fl4_gre_key = gre_hdr[1];
Timo Teräscc9ff192010-11-03 04:41:38 +0000169 }
170 }
171 break;
172
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 default:
David S. Miller9cce96d2011-03-12 03:00:33 -0500174 fl4->fl4_ipsec_spi = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 break;
Stephen Hemminger3ff50b72007-04-20 17:09:22 -0700176 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 }
David S. Miller7e1dc7b2011-03-12 02:42:11 -0500178 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182}
183
Daniel Lezcano569d3642008-01-18 03:56:57 -0800184static inline int xfrm4_garbage_collect(struct dst_ops *ops)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185{
Alexey Dobriyand7c75442010-01-24 22:47:53 -0800186 struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops);
187
188 xfrm4_policy_afinfo.garbage_collect(net);
Eric Dumazetfc66f952010-10-08 06:37:34 +0000189 return (dst_entries_get_slow(ops) > ops->gc_thresh * 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190}
191
David S. Miller6700c272012-07-17 03:29:28 -0700192static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
193 struct sk_buff *skb, u32 mtu)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194{
195 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
196 struct dst_entry *path = xdst->route;
197
David S. Miller6700c272012-07-17 03:29:28 -0700198 path->ops->update_pmtu(path, sk, skb, mtu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199}
200
David S. Miller6700c272012-07-17 03:29:28 -0700201static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
202 struct sk_buff *skb)
David S. Miller55be7a92012-07-11 21:27:49 -0700203{
204 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
205 struct dst_entry *path = xdst->route;
206
David S. Miller6700c272012-07-17 03:29:28 -0700207 path->ops->redirect(path, sk, skb);
David S. Miller55be7a92012-07-11 21:27:49 -0700208}
209
Herbert Xuaabc9762005-05-03 16:27:10 -0700210static void xfrm4_dst_destroy(struct dst_entry *dst)
211{
212 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
213
David S. Miller62fa8a82011-01-26 20:51:05 -0800214 dst_destroy_metrics_generic(dst);
215
Herbert Xuaabc9762005-05-03 16:27:10 -0700216 xfrm_dst_destroy(xdst);
217}
218
219static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
220 int unregister)
221{
Herbert Xuaabc9762005-05-03 16:27:10 -0700222 if (!unregister)
223 return;
224
Herbert Xuaabc9762005-05-03 16:27:10 -0700225 xfrm_dst_ifdown(dst, dev);
226}
227
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228static struct dst_ops xfrm4_dst_ops = {
229 .family = AF_INET,
Harvey Harrison09640e62009-02-01 00:45:17 -0800230 .protocol = cpu_to_be16(ETH_P_IP),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 .gc = xfrm4_garbage_collect,
232 .update_pmtu = xfrm4_update_pmtu,
David S. Miller55be7a92012-07-11 21:27:49 -0700233 .redirect = xfrm4_redirect,
David S. Miller62fa8a82011-01-26 20:51:05 -0800234 .cow_metrics = dst_cow_metrics_generic,
Herbert Xuaabc9762005-05-03 16:27:10 -0700235 .destroy = xfrm4_dst_destroy,
236 .ifdown = xfrm4_dst_ifdown,
Herbert Xu862b82c2007-11-13 21:43:11 -0800237 .local_out = __ip_local_out,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 .gc_thresh = 1024,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239};
240
241static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
242 .family = AF_INET,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 .dst_ops = &xfrm4_dst_ops,
244 .dst_lookup = xfrm4_dst_lookup,
Patrick McHardya1e59ab2006-09-19 12:57:34 -0700245 .get_saddr = xfrm4_get_saddr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 .decode_session = _decode_session4,
Herbert Xu25ee3282007-12-11 09:32:34 -0800247 .get_tos = xfrm4_get_tos,
Masahide NAKAMURAa1b05142007-12-20 20:41:12 -0800248 .init_path = xfrm4_init_path,
Herbert Xu25ee3282007-12-11 09:32:34 -0800249 .fill_dst = xfrm4_fill_dst,
David S. Miller2774c132011-03-01 14:59:04 -0800250 .blackhole_route = ipv4_blackhole_route,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251};
252
Randy Dunlapf8167002009-08-04 20:18:33 -0700253#ifdef CONFIG_SYSCTL
Neil Hormana44a4a02009-07-27 08:22:46 +0000254static struct ctl_table xfrm4_policy_table[] = {
255 {
Neil Hormana44a4a02009-07-27 08:22:46 +0000256 .procname = "xfrm4_gc_thresh",
Alexey Dobriyand7c75442010-01-24 22:47:53 -0800257 .data = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
Neil Hormana44a4a02009-07-27 08:22:46 +0000258 .maxlen = sizeof(int),
259 .mode = 0644,
260 .proc_handler = proc_dointvec,
261 },
262 { }
263};
264
265static struct ctl_table_header *sysctl_hdr;
Randy Dunlapf8167002009-08-04 20:18:33 -0700266#endif
Neil Hormana44a4a02009-07-27 08:22:46 +0000267
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268static void __init xfrm4_policy_init(void)
269{
270 xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
271}
272
273static void __exit xfrm4_policy_fini(void)
274{
Randy Dunlapf8167002009-08-04 20:18:33 -0700275#ifdef CONFIG_SYSCTL
Neil Hormana44a4a02009-07-27 08:22:46 +0000276 if (sysctl_hdr)
277 unregister_net_sysctl_table(sysctl_hdr);
Randy Dunlapf8167002009-08-04 20:18:33 -0700278#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo);
280}
281
Neil Hormana33bc5c2009-07-30 18:52:15 -0700282void __init xfrm4_init(int rt_max_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283{
Neil Hormana33bc5c2009-07-30 18:52:15 -0700284 /*
285 * Select a default value for the gc_thresh based on the main route
286 * table hash size. It seems to me the worst case scenario is when
287 * we have ipsec operating in transport mode, in which we create a
288 * dst_entry per socket. The xfrm gc algorithm starts trying to remove
289 * entries at gc_thresh, and prevents new allocations as 2*gc_thresh
290 * so lets set an initial xfrm gc_thresh value at the rt_max_size/2.
291 * That will let us store an ipsec connection per route table entry,
292 * and start cleaning when were 1/2 full
293 */
294 xfrm4_dst_ops.gc_thresh = rt_max_size/2;
Eric Dumazetfc66f952010-10-08 06:37:34 +0000295 dst_entries_init(&xfrm4_dst_ops);
Alexey Dobriyand7c75442010-01-24 22:47:53 -0800296
297 xfrm4_state_init();
298 xfrm4_policy_init();
Randy Dunlapf8167002009-08-04 20:18:33 -0700299#ifdef CONFIG_SYSCTL
Eric W. Biedermanec8f23c2012-04-19 13:44:49 +0000300 sysctl_hdr = register_net_sysctl(&init_net, "net/ipv4",
301 xfrm4_policy_table);
Randy Dunlapf8167002009-08-04 20:18:33 -0700302#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303}
304