xref: /openbmc/linux/net/ipv6/fib6_rules.c (revision b16fb418b1bf2a9f14d5d2a4fe29bde1f5550b37) 
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 				   const struct sk_buff *skb,
65 				   int flags, pol_lookup_t lookup)
66 {
67 	if (net->ipv6.fib6_has_custom_rules) {
68 		struct fib_lookup_arg arg = {
69 			.lookup_ptr = lookup,
70 			.lookup_data = skb,
71 			.flags = FIB_LOOKUP_NOREF,
72 		};
73 
74 		/* update flow if oif or iif point to device enslaved to l3mdev */
75 		l3mdev_update_flow(net, flowi6_to_flowi(fl6));
76 
77 		fib_rules_lookup(net->ipv6.fib6_rules_ops,
78 				 flowi6_to_flowi(fl6), flags, &arg);
79 
80 		if (arg.result)
81 			return arg.result;
82 	} else {
83 		struct rt6_info *rt;
84 
85 		rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, skb, flags);
86 		if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN)
87 			return &rt->dst;
88 		ip6_rt_put(rt);
89 		rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
90 		if (rt->dst.error != -EAGAIN)
91 			return &rt->dst;
92 		ip6_rt_put(rt);
93 	}
94 
95 	dst_hold(&net->ipv6.ip6_null_entry->dst);
96 	return &net->ipv6.ip6_null_entry->dst;
97 }
98 
99 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
100 			    int flags, struct fib_lookup_arg *arg)
101 {
102 	struct flowi6 *flp6 = &flp->u.ip6;
103 	struct rt6_info *rt = NULL;
104 	struct fib6_table *table;
105 	struct net *net = rule->fr_net;
106 	pol_lookup_t lookup = arg->lookup_ptr;
107 	int err = 0;
108 	u32 tb_id;
109 
110 	switch (rule->action) {
111 	case FR_ACT_TO_TBL:
112 		break;
113 	case FR_ACT_UNREACHABLE:
114 		err = -ENETUNREACH;
115 		rt = net->ipv6.ip6_null_entry;
116 		goto discard_pkt;
117 	default:
118 	case FR_ACT_BLACKHOLE:
119 		err = -EINVAL;
120 		rt = net->ipv6.ip6_blk_hole_entry;
121 		goto discard_pkt;
122 	case FR_ACT_PROHIBIT:
123 		err = -EACCES;
124 		rt = net->ipv6.ip6_prohibit_entry;
125 		goto discard_pkt;
126 	}
127 
128 	tb_id = fib_rule_get_table(rule, arg);
129 	table = fib6_get_table(net, tb_id);
130 	if (!table) {
131 		err = -EAGAIN;
132 		goto out;
133 	}
134 
135 	rt = lookup(net, table, flp6, arg->lookup_data, flags);
136 	if (rt != net->ipv6.ip6_null_entry) {
137 		struct fib6_rule *r = (struct fib6_rule *)rule;
138 
139 		/*
140 		 * If we need to find a source address for this traffic,
141 		 * we check the result if it meets requirement of the rule.
142 		 */
143 		if ((rule->flags & FIB_RULE_FIND_SADDR) &&
144 		    r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
145 			struct in6_addr saddr;
146 
147 			if (ipv6_dev_get_saddr(net,
148 					       ip6_dst_idev(&rt->dst)->dev,
149 					       &flp6->daddr,
150 					       rt6_flags2srcprefs(flags),
151 					       &saddr))
152 				goto again;
153 			if (!ipv6_prefix_equal(&saddr, &r->src.addr,
154 					       r->src.plen))
155 				goto again;
156 			flp6->saddr = saddr;
157 		}
158 		err = rt->dst.error;
159 		if (err != -EAGAIN)
160 			goto out;
161 	}
162 again:
163 	ip6_rt_put(rt);
164 	err = -EAGAIN;
165 	rt = NULL;
166 	goto out;
167 
168 discard_pkt:
169 	dst_hold(&rt->dst);
170 out:
171 	arg->result = rt;
172 	return err;
173 }
174 
175 static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)
176 {
177 	struct rt6_info *rt = (struct rt6_info *) arg->result;
178 	struct net_device *dev = NULL;
179 
180 	if (rt->rt6i_idev)
181 		dev = rt->rt6i_idev->dev;
182 
183 	/* do not accept result if the route does
184 	 * not meet the required prefix length
185 	 */
186 	if (rt->rt6i_dst.plen <= rule->suppress_prefixlen)
187 		goto suppress_route;
188 
189 	/* do not accept result if the route uses a device
190 	 * belonging to a forbidden interface group
191 	 */
192 	if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
193 		goto suppress_route;
194 
195 	return false;
196 
197 suppress_route:
198 	ip6_rt_put(rt);
199 	return true;
200 }
201 
202 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
203 {
204 	struct fib6_rule *r = (struct fib6_rule *) rule;
205 	struct flowi6 *fl6 = &fl->u.ip6;
206 
207 	if (r->dst.plen &&
208 	    !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen))
209 		return 0;
210 
211 	/*
212 	 * If FIB_RULE_FIND_SADDR is set and we do not have a
213 	 * source address for the traffic, we defer check for
214 	 * source address.
215 	 */
216 	if (r->src.plen) {
217 		if (flags & RT6_LOOKUP_F_HAS_SADDR) {
218 			if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr,
219 					       r->src.plen))
220 				return 0;
221 		} else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
222 			return 0;
223 	}
224 
225 	if (r->tclass && r->tclass != ip6_tclass(fl6->flowlabel))
226 		return 0;
227 
228 	if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto))
229 		return 0;
230 
231 	if (fib_rule_port_range_set(&rule->sport_range) &&
232 	    !fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport))
233 		return 0;
234 
235 	if (fib_rule_port_range_set(&rule->dport_range) &&
236 	    !fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport))
237 		return 0;
238 
239 	return 1;
240 }
241 
242 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
243 	FRA_GENERIC_POLICY,
244 };
245 
246 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
247 			       struct fib_rule_hdr *frh,
248 			       struct nlattr **tb,
249 			       struct netlink_ext_ack *extack)
250 {
251 	int err = -EINVAL;
252 	struct net *net = sock_net(skb->sk);
253 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
254 
255 	if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) {
256 		if (rule->table == RT6_TABLE_UNSPEC) {
257 			NL_SET_ERR_MSG(extack, "Invalid table");
258 			goto errout;
259 		}
260 
261 		if (fib6_new_table(net, rule->table) == NULL) {
262 			err = -ENOBUFS;
263 			goto errout;
264 		}
265 	}
266 
267 	if (frh->src_len)
268 		rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]);
269 
270 	if (frh->dst_len)
271 		rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]);
272 
273 	rule6->src.plen = frh->src_len;
274 	rule6->dst.plen = frh->dst_len;
275 	rule6->tclass = frh->tos;
276 
277 	if (fib_rule_requires_fldissect(rule))
278 		net->ipv6.fib6_rules_require_fldissect++;
279 
280 	net->ipv6.fib6_has_custom_rules = true;
281 	err = 0;
282 errout:
283 	return err;
284 }
285 
286 static int fib6_rule_delete(struct fib_rule *rule)
287 {
288 	struct net *net = rule->fr_net;
289 
290 	if (net->ipv6.fib6_rules_require_fldissect &&
291 	    fib_rule_requires_fldissect(rule))
292 		net->ipv6.fib6_rules_require_fldissect--;
293 
294 	return 0;
295 }
296 
297 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
298 			     struct nlattr **tb)
299 {
300 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
301 
302 	if (frh->src_len && (rule6->src.plen != frh->src_len))
303 		return 0;
304 
305 	if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
306 		return 0;
307 
308 	if (frh->tos && (rule6->tclass != frh->tos))
309 		return 0;
310 
311 	if (frh->src_len &&
312 	    nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
313 		return 0;
314 
315 	if (frh->dst_len &&
316 	    nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
317 		return 0;
318 
319 	return 1;
320 }
321 
322 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
323 			  struct fib_rule_hdr *frh)
324 {
325 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
326 
327 	frh->dst_len = rule6->dst.plen;
328 	frh->src_len = rule6->src.plen;
329 	frh->tos = rule6->tclass;
330 
331 	if ((rule6->dst.plen &&
332 	     nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) ||
333 	    (rule6->src.plen &&
334 	     nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr)))
335 		goto nla_put_failure;
336 	return 0;
337 
338 nla_put_failure:
339 	return -ENOBUFS;
340 }
341 
342 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
343 {
344 	return nla_total_size(16) /* dst */
345 	       + nla_total_size(16); /* src */
346 }
347 
348 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = {
349 	.family			= AF_INET6,
350 	.rule_size		= sizeof(struct fib6_rule),
351 	.addr_size		= sizeof(struct in6_addr),
352 	.action			= fib6_rule_action,
353 	.match			= fib6_rule_match,
354 	.suppress		= fib6_rule_suppress,
355 	.configure		= fib6_rule_configure,
356 	.delete			= fib6_rule_delete,
357 	.compare		= fib6_rule_compare,
358 	.fill			= fib6_rule_fill,
359 	.nlmsg_payload		= fib6_rule_nlmsg_payload,
360 	.nlgroup		= RTNLGRP_IPV6_RULE,
361 	.policy			= fib6_rule_policy,
362 	.owner			= THIS_MODULE,
363 	.fro_net		= &init_net,
364 };
365 
366 static int __net_init fib6_rules_net_init(struct net *net)
367 {
368 	struct fib_rules_ops *ops;
369 	int err = -ENOMEM;
370 
371 	ops = fib_rules_register(&fib6_rules_ops_template, net);
372 	if (IS_ERR(ops))
373 		return PTR_ERR(ops);
374 
375 	err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0);
376 	if (err)
377 		goto out_fib6_rules_ops;
378 
379 	err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0);
380 	if (err)
381 		goto out_fib6_rules_ops;
382 
383 	net->ipv6.fib6_rules_ops = ops;
384 	net->ipv6.fib6_rules_require_fldissect = 0;
385 out:
386 	return err;
387 
388 out_fib6_rules_ops:
389 	fib_rules_unregister(ops);
390 	goto out;
391 }
392 
393 static void __net_exit fib6_rules_net_exit(struct net *net)
394 {
395 	rtnl_lock();
396 	fib_rules_unregister(net->ipv6.fib6_rules_ops);
397 	rtnl_unlock();
398 }
399 
400 static struct pernet_operations fib6_rules_net_ops = {
401 	.init = fib6_rules_net_init,
402 	.exit = fib6_rules_net_exit,
403 };
404 
405 int __init fib6_rules_init(void)
406 {
407 	return register_pernet_subsys(&fib6_rules_net_ops);
408 }
409 
410 
411 void fib6_rules_cleanup(void)
412 {
413 	unregister_pernet_subsys(&fib6_rules_net_ops);
414 }
415