xref: /openbmc/linux/net/ipv6/fib6_rules.c (revision f7018c21) 
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 
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 
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 		goto out;
108 	}
109 again:
110 	ip6_rt_put(rt);
111 	err = -EAGAIN;
112 	rt = NULL;
113 	goto out;
114 
115 discard_pkt:
116 	dst_hold(&rt->dst);
117 out:
118 	arg->result = rt;
119 	return err;
120 }
121 
122 static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)
123 {
124 	struct rt6_info *rt = (struct rt6_info *) arg->result;
125 	struct net_device *dev = NULL;
126 
127 	if (rt->rt6i_idev)
128 		dev = rt->rt6i_idev->dev;
129 
130 	/* do not accept result if the route does
131 	 * not meet the required prefix length
132 	 */
133 	if (rt->rt6i_dst.plen <= rule->suppress_prefixlen)
134 		goto suppress_route;
135 
136 	/* do not accept result if the route uses a device
137 	 * belonging to a forbidden interface group
138 	 */
139 	if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
140 		goto suppress_route;
141 
142 	return false;
143 
144 suppress_route:
145 	ip6_rt_put(rt);
146 	return true;
147 }
148 
149 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
150 {
151 	struct fib6_rule *r = (struct fib6_rule *) rule;
152 	struct flowi6 *fl6 = &fl->u.ip6;
153 
154 	if (r->dst.plen &&
155 	    !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen))
156 		return 0;
157 
158 	/*
159 	 * If FIB_RULE_FIND_SADDR is set and we do not have a
160 	 * source address for the traffic, we defer check for
161 	 * source address.
162 	 */
163 	if (r->src.plen) {
164 		if (flags & RT6_LOOKUP_F_HAS_SADDR) {
165 			if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr,
166 					       r->src.plen))
167 				return 0;
168 		} else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
169 			return 0;
170 	}
171 
172 	if (r->tclass && r->tclass != ip6_tclass(fl6->flowlabel))
173 		return 0;
174 
175 	return 1;
176 }
177 
178 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
179 	FRA_GENERIC_POLICY,
180 };
181 
182 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
183 			       struct fib_rule_hdr *frh,
184 			       struct nlattr **tb)
185 {
186 	int err = -EINVAL;
187 	struct net *net = sock_net(skb->sk);
188 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
189 
190 	if (rule->action == FR_ACT_TO_TBL) {
191 		if (rule->table == RT6_TABLE_UNSPEC)
192 			goto errout;
193 
194 		if (fib6_new_table(net, rule->table) == NULL) {
195 			err = -ENOBUFS;
196 			goto errout;
197 		}
198 	}
199 
200 	if (frh->src_len)
201 		nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
202 			   sizeof(struct in6_addr));
203 
204 	if (frh->dst_len)
205 		nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
206 			   sizeof(struct in6_addr));
207 
208 	rule6->src.plen = frh->src_len;
209 	rule6->dst.plen = frh->dst_len;
210 	rule6->tclass = frh->tos;
211 
212 	err = 0;
213 errout:
214 	return err;
215 }
216 
217 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
218 			     struct nlattr **tb)
219 {
220 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
221 
222 	if (frh->src_len && (rule6->src.plen != frh->src_len))
223 		return 0;
224 
225 	if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
226 		return 0;
227 
228 	if (frh->tos && (rule6->tclass != frh->tos))
229 		return 0;
230 
231 	if (frh->src_len &&
232 	    nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
233 		return 0;
234 
235 	if (frh->dst_len &&
236 	    nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
237 		return 0;
238 
239 	return 1;
240 }
241 
242 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
243 			  struct fib_rule_hdr *frh)
244 {
245 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
246 
247 	frh->dst_len = rule6->dst.plen;
248 	frh->src_len = rule6->src.plen;
249 	frh->tos = rule6->tclass;
250 
251 	if ((rule6->dst.plen &&
252 	     nla_put(skb, FRA_DST, sizeof(struct in6_addr),
253 		     &rule6->dst.addr)) ||
254 	    (rule6->src.plen &&
255 	     nla_put(skb, FRA_SRC, sizeof(struct in6_addr),
256 		     &rule6->src.addr)))
257 		goto nla_put_failure;
258 	return 0;
259 
260 nla_put_failure:
261 	return -ENOBUFS;
262 }
263 
264 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
265 {
266 	return 0x3FFF;
267 }
268 
269 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
270 {
271 	return nla_total_size(16) /* dst */
272 	       + nla_total_size(16); /* src */
273 }
274 
275 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = {
276 	.family			= AF_INET6,
277 	.rule_size		= sizeof(struct fib6_rule),
278 	.addr_size		= sizeof(struct in6_addr),
279 	.action			= fib6_rule_action,
280 	.match			= fib6_rule_match,
281 	.suppress		= fib6_rule_suppress,
282 	.configure		= fib6_rule_configure,
283 	.compare		= fib6_rule_compare,
284 	.fill			= fib6_rule_fill,
285 	.default_pref		= fib6_rule_default_pref,
286 	.nlmsg_payload		= fib6_rule_nlmsg_payload,
287 	.nlgroup		= RTNLGRP_IPV6_RULE,
288 	.policy			= fib6_rule_policy,
289 	.owner			= THIS_MODULE,
290 	.fro_net		= &init_net,
291 };
292 
293 static int __net_init fib6_rules_net_init(struct net *net)
294 {
295 	struct fib_rules_ops *ops;
296 	int err = -ENOMEM;
297 
298 	ops = fib_rules_register(&fib6_rules_ops_template, net);
299 	if (IS_ERR(ops))
300 		return PTR_ERR(ops);
301 	net->ipv6.fib6_rules_ops = ops;
302 
303 
304 	err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
305 				   RT6_TABLE_LOCAL, 0);
306 	if (err)
307 		goto out_fib6_rules_ops;
308 
309 	err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
310 				   0x7FFE, RT6_TABLE_MAIN, 0);
311 	if (err)
312 		goto out_fib6_rules_ops;
313 
314 out:
315 	return err;
316 
317 out_fib6_rules_ops:
318 	fib_rules_unregister(ops);
319 	goto out;
320 }
321 
322 static void __net_exit fib6_rules_net_exit(struct net *net)
323 {
324 	fib_rules_unregister(net->ipv6.fib6_rules_ops);
325 }
326 
327 static struct pernet_operations fib6_rules_net_ops = {
328 	.init = fib6_rules_net_init,
329 	.exit = fib6_rules_net_exit,
330 };
331 
332 int __init fib6_rules_init(void)
333 {
334 	return register_pernet_subsys(&fib6_rules_net_ops);
335 }
336 
337 
338 void fib6_rules_cleanup(void)
339 {
340 	unregister_pernet_subsys(&fib6_rules_net_ops);
341 }
342