xref: /openbmc/linux/net/ipv6/fib6_rules.c (revision 93dc544c) 
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 
24 struct fib6_rule
25 {
26 	struct fib_rule		common;
27 	struct rt6key		src;
28 	struct rt6key		dst;
29 	u8			tclass;
30 };
31 
32 struct 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->u.dst);
47 	return &net->ipv6.ip6_null_entry->u.dst;
48 }
49 
50 static 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 			unsigned int srcprefs = 0;
88 
89 			if (flags & RT6_LOOKUP_F_SRCPREF_TMP)
90 				srcprefs |= IPV6_PREFER_SRC_TMP;
91 			if (flags & RT6_LOOKUP_F_SRCPREF_PUBLIC)
92 				srcprefs |= IPV6_PREFER_SRC_PUBLIC;
93 			if (flags & RT6_LOOKUP_F_SRCPREF_COA)
94 				srcprefs |= IPV6_PREFER_SRC_COA;
95 
96 			if (ipv6_dev_get_saddr(ip6_dst_idev(&rt->u.dst)->dev,
97 					       &flp->fl6_dst, srcprefs,
98 					       &saddr))
99 				goto again;
100 			if (!ipv6_prefix_equal(&saddr, &r->src.addr,
101 					       r->src.plen))
102 				goto again;
103 			ipv6_addr_copy(&flp->fl6_src, &saddr);
104 		}
105 		goto out;
106 	}
107 again:
108 	dst_release(&rt->u.dst);
109 	rt = NULL;
110 	goto out;
111 
112 discard_pkt:
113 	dst_hold(&rt->u.dst);
114 out:
115 	arg->result = rt;
116 	return rt == NULL ? -EAGAIN : 0;
117 }
118 
119 
120 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
121 {
122 	struct fib6_rule *r = (struct fib6_rule *) rule;
123 
124 	if (r->dst.plen &&
125 	    !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
126 		return 0;
127 
128 	/*
129 	 * If FIB_RULE_FIND_SADDR is set and we do not have a
130 	 * source address for the traffic, we defer check for
131 	 * source address.
132 	 */
133 	if (r->src.plen) {
134 		if (flags & RT6_LOOKUP_F_HAS_SADDR) {
135 			if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr,
136 					       r->src.plen))
137 				return 0;
138 		} else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
139 			return 0;
140 	}
141 
142 	if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
143 		return 0;
144 
145 	return 1;
146 }
147 
148 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
149 	FRA_GENERIC_POLICY,
150 };
151 
152 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
153 			       struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
154 			       struct nlattr **tb)
155 {
156 	int err = -EINVAL;
157 	struct net *net = sock_net(skb->sk);
158 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
159 
160 	if (rule->action == FR_ACT_TO_TBL) {
161 		if (rule->table == RT6_TABLE_UNSPEC)
162 			goto errout;
163 
164 		if (fib6_new_table(net, rule->table) == NULL) {
165 			err = -ENOBUFS;
166 			goto errout;
167 		}
168 	}
169 
170 	if (frh->src_len)
171 		nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
172 			   sizeof(struct in6_addr));
173 
174 	if (frh->dst_len)
175 		nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
176 			   sizeof(struct in6_addr));
177 
178 	rule6->src.plen = frh->src_len;
179 	rule6->dst.plen = frh->dst_len;
180 	rule6->tclass = frh->tos;
181 
182 	err = 0;
183 errout:
184 	return err;
185 }
186 
187 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
188 			     struct nlattr **tb)
189 {
190 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
191 
192 	if (frh->src_len && (rule6->src.plen != frh->src_len))
193 		return 0;
194 
195 	if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
196 		return 0;
197 
198 	if (frh->tos && (rule6->tclass != frh->tos))
199 		return 0;
200 
201 	if (frh->src_len &&
202 	    nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
203 		return 0;
204 
205 	if (frh->dst_len &&
206 	    nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
207 		return 0;
208 
209 	return 1;
210 }
211 
212 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
213 			  struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
214 {
215 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
216 
217 	frh->family = AF_INET6;
218 	frh->dst_len = rule6->dst.plen;
219 	frh->src_len = rule6->src.plen;
220 	frh->tos = rule6->tclass;
221 
222 	if (rule6->dst.plen)
223 		NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
224 			&rule6->dst.addr);
225 
226 	if (rule6->src.plen)
227 		NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
228 			&rule6->src.addr);
229 
230 	return 0;
231 
232 nla_put_failure:
233 	return -ENOBUFS;
234 }
235 
236 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
237 {
238 	return 0x3FFF;
239 }
240 
241 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
242 {
243 	return nla_total_size(16) /* dst */
244 	       + nla_total_size(16); /* src */
245 }
246 
247 static struct fib_rules_ops fib6_rules_ops_template = {
248 	.family			= AF_INET6,
249 	.rule_size		= sizeof(struct fib6_rule),
250 	.addr_size		= sizeof(struct in6_addr),
251 	.action			= fib6_rule_action,
252 	.match			= fib6_rule_match,
253 	.configure		= fib6_rule_configure,
254 	.compare		= fib6_rule_compare,
255 	.fill			= fib6_rule_fill,
256 	.default_pref		= fib6_rule_default_pref,
257 	.nlmsg_payload		= fib6_rule_nlmsg_payload,
258 	.nlgroup		= RTNLGRP_IPV6_RULE,
259 	.policy			= fib6_rule_policy,
260 	.owner			= THIS_MODULE,
261 	.fro_net		= &init_net,
262 };
263 
264 static int fib6_rules_net_init(struct net *net)
265 {
266 	int err = -ENOMEM;
267 
268 	net->ipv6.fib6_rules_ops = kmemdup(&fib6_rules_ops_template,
269 					   sizeof(*net->ipv6.fib6_rules_ops),
270 					   GFP_KERNEL);
271 	if (!net->ipv6.fib6_rules_ops)
272 		goto out;
273 
274 	net->ipv6.fib6_rules_ops->fro_net = net;
275 	INIT_LIST_HEAD(&net->ipv6.fib6_rules_ops->rules_list);
276 
277 	err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
278 				   RT6_TABLE_LOCAL, FIB_RULE_PERMANENT);
279 	if (err)
280 		goto out_fib6_rules_ops;
281 
282 	err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
283 				   0x7FFE, RT6_TABLE_MAIN, 0);
284 	if (err)
285 		goto out_fib6_default_rule_add;
286 
287 	err = fib_rules_register(net->ipv6.fib6_rules_ops);
288 	if (err)
289 		goto out_fib6_default_rule_add;
290 out:
291 	return err;
292 
293 out_fib6_default_rule_add:
294 	fib_rules_cleanup_ops(net->ipv6.fib6_rules_ops);
295 out_fib6_rules_ops:
296 	kfree(net->ipv6.fib6_rules_ops);
297 	goto out;
298 }
299 
300 static void fib6_rules_net_exit(struct net *net)
301 {
302 	fib_rules_unregister(net->ipv6.fib6_rules_ops);
303 	kfree(net->ipv6.fib6_rules_ops);
304 }
305 
306 static struct pernet_operations fib6_rules_net_ops = {
307 	.init = fib6_rules_net_init,
308 	.exit = fib6_rules_net_exit,
309 };
310 
311 int __init fib6_rules_init(void)
312 {
313 	return register_pernet_subsys(&fib6_rules_net_ops);
314 }
315 
316 
317 void fib6_rules_cleanup(void)
318 {
319 	unregister_pernet_subsys(&fib6_rules_net_ops);
320 }
321