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
32static struct fib_rules_ops fib6_rules_ops;
33
34static struct fib6_rule main_rule = {
35	.common = {
36		.refcnt =	ATOMIC_INIT(2),
37		.pref =		0x7FFE,
38		.action =	FR_ACT_TO_TBL,
39		.table =	RT6_TABLE_MAIN,
40	},
41};
42
43static struct fib6_rule local_rule = {
44	.common = {
45		.refcnt =	ATOMIC_INIT(2),
46		.pref =		0,
47		.action =	FR_ACT_TO_TBL,
48		.table =	RT6_TABLE_LOCAL,
49		.flags =	FIB_RULE_PERMANENT,
50	},
51};
52
53static LIST_HEAD(fib6_rules);
54
55struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags,
56				   pol_lookup_t lookup)
57{
58	struct fib_lookup_arg arg = {
59		.lookup_ptr = lookup,
60	};
61
62	fib_rules_lookup(&fib6_rules_ops, fl, flags, &arg);
63	if (arg.rule)
64		fib_rule_put(arg.rule);
65
66	if (arg.result)
67		return arg.result;
68
69	dst_hold(&ip6_null_entry.u.dst);
70	return &ip6_null_entry.u.dst;
71}
72
73static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
74			    int flags, struct fib_lookup_arg *arg)
75{
76	struct rt6_info *rt = NULL;
77	struct fib6_table *table;
78	pol_lookup_t lookup = arg->lookup_ptr;
79
80	switch (rule->action) {
81	case FR_ACT_TO_TBL:
82		break;
83	case FR_ACT_UNREACHABLE:
84		rt = &ip6_null_entry;
85		goto discard_pkt;
86	default:
87	case FR_ACT_BLACKHOLE:
88		rt = &ip6_blk_hole_entry;
89		goto discard_pkt;
90	case FR_ACT_PROHIBIT:
91		rt = &ip6_prohibit_entry;
92		goto discard_pkt;
93	}
94
95	table = fib6_get_table(rule->table);
96	if (table)
97		rt = lookup(table, flp, flags);
98
99	if (rt != &ip6_null_entry) {
100		struct fib6_rule *r = (struct fib6_rule *)rule;
101
102		/*
103		 * If we need to find a source address for this traffic,
104		 * we check the result if it meets requirement of the rule.
105		 */
106		if ((rule->flags & FIB_RULE_FIND_SADDR) &&
107		    r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
108			struct in6_addr saddr;
109			if (ipv6_get_saddr(&rt->u.dst, &flp->fl6_dst,
110					   &saddr))
111				goto again;
112			if (!ipv6_prefix_equal(&saddr, &r->src.addr,
113					       r->src.plen))
114				goto again;
115			ipv6_addr_copy(&flp->fl6_src, &saddr);
116		}
117		goto out;
118	}
119again:
120	dst_release(&rt->u.dst);
121	rt = NULL;
122	goto out;
123
124discard_pkt:
125	dst_hold(&rt->u.dst);
126out:
127	arg->result = rt;
128	return rt == NULL ? -EAGAIN : 0;
129}
130
131
132static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
133{
134	struct fib6_rule *r = (struct fib6_rule *) rule;
135
136	if (r->dst.plen &&
137	    !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
138		return 0;
139
140	/*
141	 * If FIB_RULE_FIND_SADDR is set and we do not have a
142	 * source address for the traffic, we defer check for
143	 * source address.
144	 */
145	if (r->src.plen) {
146		if (flags & RT6_LOOKUP_F_HAS_SADDR) {
147			if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr,
148					       r->src.plen))
149				return 0;
150		} else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
151			return 0;
152	}
153
154	if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
155		return 0;
156
157	return 1;
158}
159
160static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
161	FRA_GENERIC_POLICY,
162};
163
164static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
165			       struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
166			       struct nlattr **tb)
167{
168	int err = -EINVAL;
169	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
170
171	if (rule->action == FR_ACT_TO_TBL) {
172		if (rule->table == RT6_TABLE_UNSPEC)
173			goto errout;
174
175		if (fib6_new_table(rule->table) == NULL) {
176			err = -ENOBUFS;
177			goto errout;
178		}
179	}
180
181	if (frh->src_len)
182		nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
183			   sizeof(struct in6_addr));
184
185	if (frh->dst_len)
186		nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
187			   sizeof(struct in6_addr));
188
189	rule6->src.plen = frh->src_len;
190	rule6->dst.plen = frh->dst_len;
191	rule6->tclass = frh->tos;
192
193	err = 0;
194errout:
195	return err;
196}
197
198static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
199			     struct nlattr **tb)
200{
201	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
202
203	if (frh->src_len && (rule6->src.plen != frh->src_len))
204		return 0;
205
206	if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
207		return 0;
208
209	if (frh->tos && (rule6->tclass != frh->tos))
210		return 0;
211
212	if (frh->src_len &&
213	    nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
214		return 0;
215
216	if (frh->dst_len &&
217	    nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
218		return 0;
219
220	return 1;
221}
222
223static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
224			  struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
225{
226	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
227
228	frh->family = AF_INET6;
229	frh->dst_len = rule6->dst.plen;
230	frh->src_len = rule6->src.plen;
231	frh->tos = rule6->tclass;
232
233	if (rule6->dst.plen)
234		NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
235			&rule6->dst.addr);
236
237	if (rule6->src.plen)
238		NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
239			&rule6->src.addr);
240
241	return 0;
242
243nla_put_failure:
244	return -ENOBUFS;
245}
246
247static u32 fib6_rule_default_pref(void)
248{
249	return 0x3FFF;
250}
251
252static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
253{
254	return nla_total_size(16) /* dst */
255	       + nla_total_size(16); /* src */
256}
257
258static struct fib_rules_ops fib6_rules_ops = {
259	.family			= AF_INET6,
260	.rule_size		= sizeof(struct fib6_rule),
261	.addr_size		= sizeof(struct in6_addr),
262	.action			= fib6_rule_action,
263	.match			= fib6_rule_match,
264	.configure		= fib6_rule_configure,
265	.compare		= fib6_rule_compare,
266	.fill			= fib6_rule_fill,
267	.default_pref		= fib6_rule_default_pref,
268	.nlmsg_payload		= fib6_rule_nlmsg_payload,
269	.nlgroup		= RTNLGRP_IPV6_RULE,
270	.policy			= fib6_rule_policy,
271	.rules_list		= &fib6_rules,
272	.owner			= THIS_MODULE,
273};
274
275void __init fib6_rules_init(void)
276{
277	list_add_tail(&local_rule.common.list, &fib6_rules);
278	list_add_tail(&main_rule.common.list, &fib6_rules);
279
280	fib_rules_register(&fib6_rules_ops);
281}
282
283void fib6_rules_cleanup(void)
284{
285	fib_rules_unregister(&fib6_rules_ops);
286}
287