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
18#include <net/fib_rules.h>
19#include <net/ipv6.h>
20#include <net/addrconf.h>
21#include <net/ip6_route.h>
22#include <net/netlink.h>
23
24struct fib6_rule
25{
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 flowi *fl,
33				   int flags, pol_lookup_t lookup)
34{
35	struct fib_lookup_arg arg = {
36		.lookup_ptr = lookup,
37	};
38
39	fib_rules_lookup(net->ipv6.fib6_rules_ops, fl, flags, &arg);
40	if (arg.rule)
41		fib_rule_put(arg.rule);
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 rt6_info *rt = NULL;
54	struct fib6_table *table;
55	struct net *net = rule->fr_net;
56	pol_lookup_t lookup = arg->lookup_ptr;
57
58	switch (rule->action) {
59	case FR_ACT_TO_TBL:
60		break;
61	case FR_ACT_UNREACHABLE:
62		rt = net->ipv6.ip6_null_entry;
63		goto discard_pkt;
64	default:
65	case FR_ACT_BLACKHOLE:
66		rt = net->ipv6.ip6_blk_hole_entry;
67		goto discard_pkt;
68	case FR_ACT_PROHIBIT:
69		rt = net->ipv6.ip6_prohibit_entry;
70		goto discard_pkt;
71	}
72
73	table = fib6_get_table(net, rule->table);
74	if (table)
75		rt = lookup(net, table, flp, flags);
76
77	if (rt != net->ipv6.ip6_null_entry) {
78		struct fib6_rule *r = (struct fib6_rule *)rule;
79
80		/*
81		 * If we need to find a source address for this traffic,
82		 * we check the result if it meets requirement of the rule.
83		 */
84		if ((rule->flags & FIB_RULE_FIND_SADDR) &&
85		    r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
86			struct in6_addr saddr;
87
88			if (ipv6_dev_get_saddr(net,
89					       ip6_dst_idev(&rt->dst)->dev,
90					       &flp->fl6_dst,
91					       rt6_flags2srcprefs(flags),
92					       &saddr))
93				goto again;
94			if (!ipv6_prefix_equal(&saddr, &r->src.addr,
95					       r->src.plen))
96				goto again;
97			ipv6_addr_copy(&flp->fl6_src, &saddr);
98		}
99		goto out;
100	}
101again:
102	dst_release(&rt->dst);
103	rt = NULL;
104	goto out;
105
106discard_pkt:
107	dst_hold(&rt->dst);
108out:
109	arg->result = rt;
110	return rt == NULL ? -EAGAIN : 0;
111}
112
113
114static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
115{
116	struct fib6_rule *r = (struct fib6_rule *) rule;
117
118	if (r->dst.plen &&
119	    !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
120		return 0;
121
122	/*
123	 * If FIB_RULE_FIND_SADDR is set and we do not have a
124	 * source address for the traffic, we defer check for
125	 * source address.
126	 */
127	if (r->src.plen) {
128		if (flags & RT6_LOOKUP_F_HAS_SADDR) {
129			if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr,
130					       r->src.plen))
131				return 0;
132		} else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
133			return 0;
134	}
135
136	if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
137		return 0;
138
139	return 1;
140}
141
142static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
143	FRA_GENERIC_POLICY,
144};
145
146static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
147			       struct fib_rule_hdr *frh,
148			       struct nlattr **tb)
149{
150	int err = -EINVAL;
151	struct net *net = sock_net(skb->sk);
152	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
153
154	if (rule->action == FR_ACT_TO_TBL) {
155		if (rule->table == RT6_TABLE_UNSPEC)
156			goto errout;
157
158		if (fib6_new_table(net, rule->table) == NULL) {
159			err = -ENOBUFS;
160			goto errout;
161		}
162	}
163
164	if (frh->src_len)
165		nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
166			   sizeof(struct in6_addr));
167
168	if (frh->dst_len)
169		nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
170			   sizeof(struct in6_addr));
171
172	rule6->src.plen = frh->src_len;
173	rule6->dst.plen = frh->dst_len;
174	rule6->tclass = frh->tos;
175
176	err = 0;
177errout:
178	return err;
179}
180
181static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
182			     struct nlattr **tb)
183{
184	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
185
186	if (frh->src_len && (rule6->src.plen != frh->src_len))
187		return 0;
188
189	if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
190		return 0;
191
192	if (frh->tos && (rule6->tclass != frh->tos))
193		return 0;
194
195	if (frh->src_len &&
196	    nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
197		return 0;
198
199	if (frh->dst_len &&
200	    nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
201		return 0;
202
203	return 1;
204}
205
206static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
207			  struct fib_rule_hdr *frh)
208{
209	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
210
211	frh->dst_len = rule6->dst.plen;
212	frh->src_len = rule6->src.plen;
213	frh->tos = rule6->tclass;
214
215	if (rule6->dst.plen)
216		NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
217			&rule6->dst.addr);
218
219	if (rule6->src.plen)
220		NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
221			&rule6->src.addr);
222
223	return 0;
224
225nla_put_failure:
226	return -ENOBUFS;
227}
228
229static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
230{
231	return 0x3FFF;
232}
233
234static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
235{
236	return nla_total_size(16) /* dst */
237	       + nla_total_size(16); /* src */
238}
239
240static const struct fib_rules_ops __net_initdata fib6_rules_ops_template = {
241	.family			= AF_INET6,
242	.rule_size		= sizeof(struct fib6_rule),
243	.addr_size		= sizeof(struct in6_addr),
244	.action			= fib6_rule_action,
245	.match			= fib6_rule_match,
246	.configure		= fib6_rule_configure,
247	.compare		= fib6_rule_compare,
248	.fill			= fib6_rule_fill,
249	.default_pref		= fib6_rule_default_pref,
250	.nlmsg_payload		= fib6_rule_nlmsg_payload,
251	.nlgroup		= RTNLGRP_IPV6_RULE,
252	.policy			= fib6_rule_policy,
253	.owner			= THIS_MODULE,
254	.fro_net		= &init_net,
255};
256
257static int __net_init fib6_rules_net_init(struct net *net)
258{
259	struct fib_rules_ops *ops;
260	int err = -ENOMEM;
261
262	ops = fib_rules_register(&fib6_rules_ops_template, net);
263	if (IS_ERR(ops))
264		return PTR_ERR(ops);
265	net->ipv6.fib6_rules_ops = ops;
266
267
268	err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
269				   RT6_TABLE_LOCAL, 0);
270	if (err)
271		goto out_fib6_rules_ops;
272
273	err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
274				   0x7FFE, RT6_TABLE_MAIN, 0);
275	if (err)
276		goto out_fib6_rules_ops;
277
278out:
279	return err;
280
281out_fib6_rules_ops:
282	fib_rules_unregister(ops);
283	goto out;
284}
285
286static void __net_exit fib6_rules_net_exit(struct net *net)
287{
288	fib_rules_unregister(net->ipv6.fib6_rules_ops);
289}
290
291static struct pernet_operations fib6_rules_net_ops = {
292	.init = fib6_rules_net_init,
293	.exit = fib6_rules_net_exit,
294};
295
296int __init fib6_rules_init(void)
297{
298	return register_pernet_subsys(&fib6_rules_net_ops);
299}
300
301
302void fib6_rules_cleanup(void)
303{
304	unregister_pernet_subsys(&fib6_rules_net_ops);
305}
306