1 /*
2 * net/ipv6/fib6_rules.c IPv6 Routing Policy Rules
3 *
4 * Copyright (C)2003-2006 Helsinki University of Technology
5 * Copyright (C)2003-2006 USAGI/WIDE Project
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as
9 * published by the Free Software Foundation, version 2.
10 *
11 * Authors
12 * Thomas Graf <tgraf@suug.ch>
13 * Ville Nuorvala <vnuorval@tcs.hut.fi>
14 */
15
16 #include <linux/netdevice.h>
17 #include <linux/export.h>
18
19 #include <net/fib_rules.h>
20 #include <net/ipv6.h>
21 #include <net/addrconf.h>
22 #include <net/ip6_route.h>
23 #include <net/netlink.h>
24
25 struct fib6_rule {
26 struct fib_rule common;
27 struct rt6key src;
28 struct rt6key dst;
29 u8 tclass;
30 };
31
fib6_rule_lookup(struct net * net,struct flowi6 * fl6,int flags,pol_lookup_t lookup)32 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
33 int flags, pol_lookup_t lookup)
34 {
35 struct fib_lookup_arg arg = {
36 .lookup_ptr = lookup,
37 .flags = FIB_LOOKUP_NOREF,
38 };
39
40 fib_rules_lookup(net->ipv6.fib6_rules_ops,
41 flowi6_to_flowi(fl6), flags, &arg);
42
43 if (arg.result)
44 return arg.result;
45
46 dst_hold(&net->ipv6.ip6_null_entry->dst);
47 return &net->ipv6.ip6_null_entry->dst;
48 }
49
fib6_rule_action(struct fib_rule * rule,struct flowi * flp,int flags,struct fib_lookup_arg * arg)50 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
51 int flags, struct fib_lookup_arg *arg)
52 {
53 struct flowi6 *flp6 = &flp->u.ip6;
54 struct rt6_info *rt = NULL;
55 struct fib6_table *table;
56 struct net *net = rule->fr_net;
57 pol_lookup_t lookup = arg->lookup_ptr;
58 int err = 0;
59
60 switch (rule->action) {
61 case FR_ACT_TO_TBL:
62 break;
63 case FR_ACT_UNREACHABLE:
64 err = -ENETUNREACH;
65 rt = net->ipv6.ip6_null_entry;
66 goto discard_pkt;
67 default:
68 case FR_ACT_BLACKHOLE:
69 err = -EINVAL;
70 rt = net->ipv6.ip6_blk_hole_entry;
71 goto discard_pkt;
72 case FR_ACT_PROHIBIT:
73 err = -EACCES;
74 rt = net->ipv6.ip6_prohibit_entry;
75 goto discard_pkt;
76 }
77
78 table = fib6_get_table(net, rule->table);
79 if (!table) {
80 err = -EAGAIN;
81 goto out;
82 }
83
84 rt = lookup(net, table, flp6, flags);
85 if (rt != net->ipv6.ip6_null_entry) {
86 struct fib6_rule *r = (struct fib6_rule *)rule;
87
88 /*
89 * If we need to find a source address for this traffic,
90 * we check the result if it meets requirement of the rule.
91 */
92 if ((rule->flags & FIB_RULE_FIND_SADDR) &&
93 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
94 struct in6_addr saddr;
95
96 if (ipv6_dev_get_saddr(net,
97 ip6_dst_idev(&rt->dst)->dev,
98 &flp6->daddr,
99 rt6_flags2srcprefs(flags),
100 &saddr))
101 goto again;
102 if (!ipv6_prefix_equal(&saddr, &r->src.addr,
103 r->src.plen))
104 goto again;
105 flp6->saddr = saddr;
106 }
107 err = rt->dst.error;
108 goto out;
109 }
110 again:
111 ip6_rt_put(rt);
112 err = -EAGAIN;
113 rt = NULL;
114 goto out;
115
116 discard_pkt:
117 dst_hold(&rt->dst);
118 out:
119 arg->result = rt;
120 return err;
121 }
122
fib6_rule_suppress(struct fib_rule * rule,struct fib_lookup_arg * arg)123 static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)
124 {
125 struct rt6_info *rt = (struct rt6_info *) arg->result;
126 struct net_device *dev = NULL;
127
128 if (rt->rt6i_idev)
129 dev = rt->rt6i_idev->dev;
130
131 /* do not accept result if the route does
132 * not meet the required prefix length
133 */
134 if (rt->rt6i_dst.plen <= rule->suppress_prefixlen)
135 goto suppress_route;
136
137 /* do not accept result if the route uses a device
138 * belonging to a forbidden interface group
139 */
140 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
141 goto suppress_route;
142
143 return false;
144
145 suppress_route:
146 ip6_rt_put(rt);
147 return true;
148 }
149
fib6_rule_match(struct fib_rule * rule,struct flowi * fl,int flags)150 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
151 {
152 struct fib6_rule *r = (struct fib6_rule *) rule;
153 struct flowi6 *fl6 = &fl->u.ip6;
154
155 if (r->dst.plen &&
156 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen))
157 return 0;
158
159 /*
160 * If FIB_RULE_FIND_SADDR is set and we do not have a
161 * source address for the traffic, we defer check for
162 * source address.
163 */
164 if (r->src.plen) {
165 if (flags & RT6_LOOKUP_F_HAS_SADDR) {
166 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr,
167 r->src.plen))
168 return 0;
169 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
170 return 0;
171 }
172
173 if (r->tclass && r->tclass != ip6_tclass(fl6->flowlabel))
174 return 0;
175
176 return 1;
177 }
178
179 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
180 FRA_GENERIC_POLICY,
181 };
182
fib6_rule_configure(struct fib_rule * rule,struct sk_buff * skb,struct fib_rule_hdr * frh,struct nlattr ** tb)183 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
184 struct fib_rule_hdr *frh,
185 struct nlattr **tb)
186 {
187 int err = -EINVAL;
188 struct net *net = sock_net(skb->sk);
189 struct fib6_rule *rule6 = (struct fib6_rule *) rule;
190
191 if (rule->action == FR_ACT_TO_TBL) {
192 if (rule->table == RT6_TABLE_UNSPEC)
193 goto errout;
194
195 if (fib6_new_table(net, rule->table) == NULL) {
196 err = -ENOBUFS;
197 goto errout;
198 }
199 }
200
201 if (frh->src_len)
202 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
203 sizeof(struct in6_addr));
204
205 if (frh->dst_len)
206 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
207 sizeof(struct in6_addr));
208
209 rule6->src.plen = frh->src_len;
210 rule6->dst.plen = frh->dst_len;
211 rule6->tclass = frh->tos;
212
213 err = 0;
214 errout:
215 return err;
216 }
217
fib6_rule_compare(struct fib_rule * rule,struct fib_rule_hdr * frh,struct nlattr ** tb)218 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
219 struct nlattr **tb)
220 {
221 struct fib6_rule *rule6 = (struct fib6_rule *) rule;
222
223 if (frh->src_len && (rule6->src.plen != frh->src_len))
224 return 0;
225
226 if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
227 return 0;
228
229 if (frh->tos && (rule6->tclass != frh->tos))
230 return 0;
231
232 if (frh->src_len &&
233 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
234 return 0;
235
236 if (frh->dst_len &&
237 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
238 return 0;
239
240 return 1;
241 }
242
fib6_rule_fill(struct fib_rule * rule,struct sk_buff * skb,struct fib_rule_hdr * frh)243 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
244 struct fib_rule_hdr *frh)
245 {
246 struct fib6_rule *rule6 = (struct fib6_rule *) rule;
247
248 frh->dst_len = rule6->dst.plen;
249 frh->src_len = rule6->src.plen;
250 frh->tos = rule6->tclass;
251
252 if ((rule6->dst.plen &&
253 nla_put(skb, FRA_DST, sizeof(struct in6_addr),
254 &rule6->dst.addr)) ||
255 (rule6->src.plen &&
256 nla_put(skb, FRA_SRC, sizeof(struct in6_addr),
257 &rule6->src.addr)))
258 goto nla_put_failure;
259 return 0;
260
261 nla_put_failure:
262 return -ENOBUFS;
263 }
264
fib6_rule_default_pref(struct fib_rules_ops * ops)265 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
266 {
267 return 0x3FFF;
268 }
269
fib6_rule_nlmsg_payload(struct fib_rule * rule)270 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
271 {
272 return nla_total_size(16) /* dst */
273 + nla_total_size(16); /* src */
274 }
275
276 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = {
277 .family = AF_INET6,
278 .rule_size = sizeof(struct fib6_rule),
279 .addr_size = sizeof(struct in6_addr),
280 .action = fib6_rule_action,
281 .match = fib6_rule_match,
282 .suppress = fib6_rule_suppress,
283 .configure = fib6_rule_configure,
284 .compare = fib6_rule_compare,
285 .fill = fib6_rule_fill,
286 .default_pref = fib6_rule_default_pref,
287 .nlmsg_payload = fib6_rule_nlmsg_payload,
288 .nlgroup = RTNLGRP_IPV6_RULE,
289 .policy = fib6_rule_policy,
290 .owner = THIS_MODULE,
291 .fro_net = &init_net,
292 };
293
fib6_rules_net_init(struct net * net)294 static int __net_init fib6_rules_net_init(struct net *net)
295 {
296 struct fib_rules_ops *ops;
297 int err = -ENOMEM;
298
299 ops = fib_rules_register(&fib6_rules_ops_template, net);
300 if (IS_ERR(ops))
301 return PTR_ERR(ops);
302 net->ipv6.fib6_rules_ops = ops;
303
304
305 err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
306 RT6_TABLE_LOCAL, 0);
307 if (err)
308 goto out_fib6_rules_ops;
309
310 err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
311 0x7FFE, RT6_TABLE_MAIN, 0);
312 if (err)
313 goto out_fib6_rules_ops;
314
315 out:
316 return err;
317
318 out_fib6_rules_ops:
319 fib_rules_unregister(ops);
320 goto out;
321 }
322
fib6_rules_net_exit(struct net * net)323 static void __net_exit fib6_rules_net_exit(struct net *net)
324 {
325 fib_rules_unregister(net->ipv6.fib6_rules_ops);
326 }
327
328 static struct pernet_operations fib6_rules_net_ops = {
329 .init = fib6_rules_net_init,
330 .exit = fib6_rules_net_exit,
331 };
332
fib6_rules_init(void)333 int __init fib6_rules_init(void)
334 {
335 return register_pernet_subsys(&fib6_rules_net_ops);
336 }
337
338
fib6_rules_cleanup(void)339 void fib6_rules_cleanup(void)
340 {
341 unregister_pernet_subsys(&fib6_rules_net_ops);
342 }
343