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
25struct fib6_rule {
26	struct fib_rule		common;
27	struct rt6key		src;
28	struct rt6key		dst;
29	u8			tclass;
30};
31
32struct 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
50static 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	}
109again:
110	ip6_rt_put(rt);
111	err = -EAGAIN;
112	rt = NULL;
113	goto out;
114
115discard_pkt:
116	dst_hold(&rt->dst);
117out:
118	arg->result = rt;
119	return err;
120}
121
122static 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
144suppress_route:
145	ip6_rt_put(rt);
146	return true;
147}
148
149static 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
178static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
179	FRA_GENERIC_POLICY,
180};
181
182static 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;
213errout:
214	return err;
215}
216
217static 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
242static 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
260nla_put_failure:
261	return -ENOBUFS;
262}
263
264static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
265{
266	return 0x3FFF;
267}
268
269static 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
275static 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
293static 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
314out:
315	return err;
316
317out_fib6_rules_ops:
318	fib_rules_unregister(ops);
319	goto out;
320}
321
322static void __net_exit fib6_rules_net_exit(struct net *net)
323{
324	fib_rules_unregister(net->ipv6.fib6_rules_ops);
325}
326
327static struct pernet_operations fib6_rules_net_ops = {
328	.init = fib6_rules_net_init,
329	.exit = fib6_rules_net_exit,
330};
331
332int __init fib6_rules_init(void)
333{
334	return register_pernet_subsys(&fib6_rules_net_ops);
335}
336
337
338void fib6_rules_cleanup(void)
339{
340	unregister_pernet_subsys(&fib6_rules_net_ops);
341}
342