xref: /openbmc/linux/net/ipv6/fib6_rules.c (revision a25724b05af0e38232764fc0d0f984254e4b5c41) 
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/notifier.h>
18 #include <linux/export.h>
19 
20 #include <net/fib_rules.h>
21 #include <net/ipv6.h>
22 #include <net/addrconf.h>
23 #include <net/ip6_route.h>
24 #include <net/netlink.h>
25 
26 struct fib6_rule {
27 	struct fib_rule		common;
28 	struct rt6key		src;
29 	struct rt6key		dst;
30 	u8			tclass;
31 };
32 
33 static bool fib6_rule_matchall(const struct fib_rule *rule)
34 {
35 	struct fib6_rule *r = container_of(rule, struct fib6_rule, common);
36 
37 	if (r->dst.plen || r->src.plen || r->tclass)
38 		return false;
39 	return fib_rule_matchall(rule);
40 }
41 
42 bool fib6_rule_default(const struct fib_rule *rule)
43 {
44 	if (!fib6_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL ||
45 	    rule->l3mdev)
46 		return false;
47 	if (rule->table != RT6_TABLE_LOCAL && rule->table != RT6_TABLE_MAIN)
48 		return false;
49 	return true;
50 }
51 EXPORT_SYMBOL_GPL(fib6_rule_default);
52 
53 int fib6_rules_dump(struct net *net, struct notifier_block *nb)
54 {
55 	return fib_rules_dump(net, nb, AF_INET6);
56 }
57 
58 unsigned int fib6_rules_seq_read(struct net *net)
59 {
60 	return fib_rules_seq_read(net, AF_INET6);
61 }
62 
63 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
64 				   int flags, pol_lookup_t lookup)
65 {
66 	if (net->ipv6.fib6_has_custom_rules) {
67 		struct fib_lookup_arg arg = {
68 			.lookup_ptr = lookup,
69 			.flags = FIB_LOOKUP_NOREF,
70 		};
71 
72 		/* update flow if oif or iif point to device enslaved to l3mdev */
73 		l3mdev_update_flow(net, flowi6_to_flowi(fl6));
74 
75 		fib_rules_lookup(net->ipv6.fib6_rules_ops,
76 				 flowi6_to_flowi(fl6), flags, &arg);
77 
78 		if (arg.result)
79 			return arg.result;
80 	} else {
81 		struct rt6_info *rt;
82 
83 		rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, flags);
84 		if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN)
85 			return &rt->dst;
86 		ip6_rt_put(rt);
87 		rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
88 		if (rt->dst.error != -EAGAIN)
89 			return &rt->dst;
90 		ip6_rt_put(rt);
91 	}
92 
93 	dst_hold(&net->ipv6.ip6_null_entry->dst);
94 	return &net->ipv6.ip6_null_entry->dst;
95 }
96 
97 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
98 			    int flags, struct fib_lookup_arg *arg)
99 {
100 	struct flowi6 *flp6 = &flp->u.ip6;
101 	struct rt6_info *rt = NULL;
102 	struct fib6_table *table;
103 	struct net *net = rule->fr_net;
104 	pol_lookup_t lookup = arg->lookup_ptr;
105 	int err = 0;
106 	u32 tb_id;
107 
108 	switch (rule->action) {
109 	case FR_ACT_TO_TBL:
110 		break;
111 	case FR_ACT_UNREACHABLE:
112 		err = -ENETUNREACH;
113 		rt = net->ipv6.ip6_null_entry;
114 		goto discard_pkt;
115 	default:
116 	case FR_ACT_BLACKHOLE:
117 		err = -EINVAL;
118 		rt = net->ipv6.ip6_blk_hole_entry;
119 		goto discard_pkt;
120 	case FR_ACT_PROHIBIT:
121 		err = -EACCES;
122 		rt = net->ipv6.ip6_prohibit_entry;
123 		goto discard_pkt;
124 	}
125 
126 	tb_id = fib_rule_get_table(rule, arg);
127 	table = fib6_get_table(net, tb_id);
128 	if (!table) {
129 		err = -EAGAIN;
130 		goto out;
131 	}
132 
133 	rt = lookup(net, table, flp6, flags);
134 	if (rt != net->ipv6.ip6_null_entry) {
135 		struct fib6_rule *r = (struct fib6_rule *)rule;
136 
137 		/*
138 		 * If we need to find a source address for this traffic,
139 		 * we check the result if it meets requirement of the rule.
140 		 */
141 		if ((rule->flags & FIB_RULE_FIND_SADDR) &&
142 		    r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
143 			struct in6_addr saddr;
144 
145 			if (ipv6_dev_get_saddr(net,
146 					       ip6_dst_idev(&rt->dst)->dev,
147 					       &flp6->daddr,
148 					       rt6_flags2srcprefs(flags),
149 					       &saddr))
150 				goto again;
151 			if (!ipv6_prefix_equal(&saddr, &r->src.addr,
152 					       r->src.plen))
153 				goto again;
154 			flp6->saddr = saddr;
155 		}
156 		err = rt->dst.error;
157 		if (err != -EAGAIN)
158 			goto out;
159 	}
160 again:
161 	ip6_rt_put(rt);
162 	err = -EAGAIN;
163 	rt = NULL;
164 	goto out;
165 
166 discard_pkt:
167 	dst_hold(&rt->dst);
168 out:
169 	arg->result = rt;
170 	return err;
171 }
172 
173 static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)
174 {
175 	struct rt6_info *rt = (struct rt6_info *) arg->result;
176 	struct net_device *dev = NULL;
177 
178 	if (rt->rt6i_idev)
179 		dev = rt->rt6i_idev->dev;
180 
181 	/* do not accept result if the route does
182 	 * not meet the required prefix length
183 	 */
184 	if (rt->rt6i_dst.plen <= rule->suppress_prefixlen)
185 		goto suppress_route;
186 
187 	/* do not accept result if the route uses a device
188 	 * belonging to a forbidden interface group
189 	 */
190 	if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
191 		goto suppress_route;
192 
193 	return false;
194 
195 suppress_route:
196 	ip6_rt_put(rt);
197 	return true;
198 }
199 
200 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
201 {
202 	struct fib6_rule *r = (struct fib6_rule *) rule;
203 	struct flowi6 *fl6 = &fl->u.ip6;
204 
205 	if (r->dst.plen &&
206 	    !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen))
207 		return 0;
208 
209 	/*
210 	 * If FIB_RULE_FIND_SADDR is set and we do not have a
211 	 * source address for the traffic, we defer check for
212 	 * source address.
213 	 */
214 	if (r->src.plen) {
215 		if (flags & RT6_LOOKUP_F_HAS_SADDR) {
216 			if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr,
217 					       r->src.plen))
218 				return 0;
219 		} else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
220 			return 0;
221 	}
222 
223 	if (r->tclass && r->tclass != ip6_tclass(fl6->flowlabel))
224 		return 0;
225 
226 	if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto))
227 		return 0;
228 
229 	if (fib_rule_port_range_set(&rule->sport_range) &&
230 	    !fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport))
231 		return 0;
232 
233 	if (fib_rule_port_range_set(&rule->dport_range) &&
234 	    !fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport))
235 		return 0;
236 
237 	return 1;
238 }
239 
240 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
241 	FRA_GENERIC_POLICY,
242 };
243 
244 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
245 			       struct fib_rule_hdr *frh,
246 			       struct nlattr **tb)
247 {
248 	int err = -EINVAL;
249 	struct net *net = sock_net(skb->sk);
250 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
251 
252 	if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) {
253 		if (rule->table == RT6_TABLE_UNSPEC)
254 			goto errout;
255 
256 		if (fib6_new_table(net, rule->table) == NULL) {
257 			err = -ENOBUFS;
258 			goto errout;
259 		}
260 	}
261 
262 	if (frh->src_len)
263 		rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]);
264 
265 	if (frh->dst_len)
266 		rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]);
267 
268 	rule6->src.plen = frh->src_len;
269 	rule6->dst.plen = frh->dst_len;
270 	rule6->tclass = frh->tos;
271 
272 	if (fib_rule_requires_fldissect(rule))
273 		net->ipv6.fib6_rules_require_fldissect++;
274 
275 	net->ipv6.fib6_has_custom_rules = true;
276 	err = 0;
277 errout:
278 	return err;
279 }
280 
281 static int fib6_rule_delete(struct fib_rule *rule)
282 {
283 	struct net *net = rule->fr_net;
284 
285 	if (net->ipv6.fib6_rules_require_fldissect &&
286 	    fib_rule_requires_fldissect(rule))
287 		net->ipv6.fib6_rules_require_fldissect--;
288 
289 	return 0;
290 }
291 
292 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
293 			     struct nlattr **tb)
294 {
295 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
296 
297 	if (frh->src_len && (rule6->src.plen != frh->src_len))
298 		return 0;
299 
300 	if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
301 		return 0;
302 
303 	if (frh->tos && (rule6->tclass != frh->tos))
304 		return 0;
305 
306 	if (frh->src_len &&
307 	    nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
308 		return 0;
309 
310 	if (frh->dst_len &&
311 	    nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
312 		return 0;
313 
314 	return 1;
315 }
316 
317 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
318 			  struct fib_rule_hdr *frh)
319 {
320 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
321 
322 	frh->dst_len = rule6->dst.plen;
323 	frh->src_len = rule6->src.plen;
324 	frh->tos = rule6->tclass;
325 
326 	if ((rule6->dst.plen &&
327 	     nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) ||
328 	    (rule6->src.plen &&
329 	     nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr)))
330 		goto nla_put_failure;
331 	return 0;
332 
333 nla_put_failure:
334 	return -ENOBUFS;
335 }
336 
337 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
338 {
339 	return nla_total_size(16) /* dst */
340 	       + nla_total_size(16); /* src */
341 }
342 
343 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = {
344 	.family			= AF_INET6,
345 	.rule_size		= sizeof(struct fib6_rule),
346 	.addr_size		= sizeof(struct in6_addr),
347 	.action			= fib6_rule_action,
348 	.match			= fib6_rule_match,
349 	.suppress		= fib6_rule_suppress,
350 	.configure		= fib6_rule_configure,
351 	.delete			= fib6_rule_delete,
352 	.compare		= fib6_rule_compare,
353 	.fill			= fib6_rule_fill,
354 	.nlmsg_payload		= fib6_rule_nlmsg_payload,
355 	.nlgroup		= RTNLGRP_IPV6_RULE,
356 	.policy			= fib6_rule_policy,
357 	.owner			= THIS_MODULE,
358 	.fro_net		= &init_net,
359 };
360 
361 static int __net_init fib6_rules_net_init(struct net *net)
362 {
363 	struct fib_rules_ops *ops;
364 	int err = -ENOMEM;
365 
366 	ops = fib_rules_register(&fib6_rules_ops_template, net);
367 	if (IS_ERR(ops))
368 		return PTR_ERR(ops);
369 
370 	err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0);
371 	if (err)
372 		goto out_fib6_rules_ops;
373 
374 	err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0);
375 	if (err)
376 		goto out_fib6_rules_ops;
377 
378 	net->ipv6.fib6_rules_ops = ops;
379 	net->ipv6.fib6_rules_require_fldissect = 0;
380 out:
381 	return err;
382 
383 out_fib6_rules_ops:
384 	fib_rules_unregister(ops);
385 	goto out;
386 }
387 
388 static void __net_exit fib6_rules_net_exit(struct net *net)
389 {
390 	rtnl_lock();
391 	fib_rules_unregister(net->ipv6.fib6_rules_ops);
392 	rtnl_unlock();
393 }
394 
395 static struct pernet_operations fib6_rules_net_ops = {
396 	.init = fib6_rules_net_init,
397 	.exit = fib6_rules_net_exit,
398 	.async = true,
399 };
400 
401 int __init fib6_rules_init(void)
402 {
403 	return register_pernet_subsys(&fib6_rules_net_ops);
404 }
405 
406 
407 void fib6_rules_cleanup(void)
408 {
409 	unregister_pernet_subsys(&fib6_rules_net_ops);
410 }
411