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 static struct fib_rules_ops fib6_rules_ops;
33
34 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags,
35 pol_lookup_t lookup)
36 {
37 struct fib_lookup_arg arg = {
38 .lookup_ptr = lookup,
39 };
40
41 fib_rules_lookup(&fib6_rules_ops, fl, flags, &arg);
42 if (arg.rule)
43 fib_rule_put(arg.rule);
44
45 if (arg.result)
46 return arg.result;
47
48 dst_hold(&ip6_null_entry.u.dst);
49 return &ip6_null_entry.u.dst;
50 }
51
52 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
53 int flags, struct fib_lookup_arg *arg)
54 {
55 struct rt6_info *rt = NULL;
56 struct fib6_table *table;
57 pol_lookup_t lookup = arg->lookup_ptr;
58
59 switch (rule->action) {
60 case FR_ACT_TO_TBL:
61 break;
62 case FR_ACT_UNREACHABLE:
63 rt = &ip6_null_entry;
64 goto discard_pkt;
65 default:
66 case FR_ACT_BLACKHOLE:
67 rt = &ip6_blk_hole_entry;
68 goto discard_pkt;
69 case FR_ACT_PROHIBIT:
70 rt = &ip6_prohibit_entry;
71 goto discard_pkt;
72 }
73
74 table = fib6_get_table(rule->table);
75 if (table)
76 rt = lookup(table, flp, flags);
77
78 if (rt != &ip6_null_entry) {
79 struct fib6_rule *r = (struct fib6_rule *)rule;
80
81 /*
82 * If we need to find a source address for this traffic,
83 * we check the result if it meets requirement of the rule.
84 */
85 if ((rule->flags & FIB_RULE_FIND_SADDR) &&
86 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
87 struct in6_addr saddr;
88 if (ipv6_get_saddr(&rt->u.dst, &flp->fl6_dst,
89 &saddr))
90 goto again;
91 if (!ipv6_prefix_equal(&saddr, &r->src.addr,
92 r->src.plen))
93 goto again;
94 ipv6_addr_copy(&flp->fl6_src, &saddr);
95 }
96 goto out;
97 }
98 again:
99 dst_release(&rt->u.dst);
100 rt = NULL;
101 goto out;
102
103 discard_pkt:
104 dst_hold(&rt->u.dst);
105 out:
106 arg->result = rt;
107 return rt == NULL ? -EAGAIN : 0;
108 }
109
110
111 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
112 {
113 struct fib6_rule *r = (struct fib6_rule *) rule;
114
115 if (r->dst.plen &&
116 !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
117 return 0;
118
119 /*
120 * If FIB_RULE_FIND_SADDR is set and we do not have a
121 * source address for the traffic, we defer check for
122 * source address.
123 */
124 if (r->src.plen) {
125 if (flags & RT6_LOOKUP_F_HAS_SADDR) {
126 if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr,
127 r->src.plen))
128 return 0;
129 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
130 return 0;
131 }
132
133 if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
134 return 0;
135
136 return 1;
137 }
138
139 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
140 FRA_GENERIC_POLICY,
141 };
142
143 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
144 struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
145 struct nlattr **tb)
146 {
147 int err = -EINVAL;
148 struct fib6_rule *rule6 = (struct fib6_rule *) rule;
149
150 if (rule->action == FR_ACT_TO_TBL) {
151 if (rule->table == RT6_TABLE_UNSPEC)
152 goto errout;
153
154 if (fib6_new_table(rule->table) == NULL) {
155 err = -ENOBUFS;
156 goto errout;
157 }
158 }
159
160 if (frh->src_len)
161 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
162 sizeof(struct in6_addr));
163
164 if (frh->dst_len)
165 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
166 sizeof(struct in6_addr));
167
168 rule6->src.plen = frh->src_len;
169 rule6->dst.plen = frh->dst_len;
170 rule6->tclass = frh->tos;
171
172 err = 0;
173 errout:
174 return err;
175 }
176
177 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
178 struct nlattr **tb)
179 {
180 struct fib6_rule *rule6 = (struct fib6_rule *) rule;
181
182 if (frh->src_len && (rule6->src.plen != frh->src_len))
183 return 0;
184
185 if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
186 return 0;
187
188 if (frh->tos && (rule6->tclass != frh->tos))
189 return 0;
190
191 if (frh->src_len &&
192 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
193 return 0;
194
195 if (frh->dst_len &&
196 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
197 return 0;
198
199 return 1;
200 }
201
202 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
203 struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
204 {
205 struct fib6_rule *rule6 = (struct fib6_rule *) rule;
206
207 frh->family = AF_INET6;
208 frh->dst_len = rule6->dst.plen;
209 frh->src_len = rule6->src.plen;
210 frh->tos = rule6->tclass;
211
212 if (rule6->dst.plen)
213 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
214 &rule6->dst.addr);
215
216 if (rule6->src.plen)
217 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
218 &rule6->src.addr);
219
220 return 0;
221
222 nla_put_failure:
223 return -ENOBUFS;
224 }
225
226 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
227 {
228 return 0x3FFF;
229 }
230
231 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
232 {
233 return nla_total_size(16) /* dst */
234 + nla_total_size(16); /* src */
235 }
236
237 static struct fib_rules_ops fib6_rules_ops = {
238 .family = AF_INET6,
239 .rule_size = sizeof(struct fib6_rule),
240 .addr_size = sizeof(struct in6_addr),
241 .action = fib6_rule_action,
242 .match = fib6_rule_match,
243 .configure = fib6_rule_configure,
244 .compare = fib6_rule_compare,
245 .fill = fib6_rule_fill,
246 .default_pref = fib6_rule_default_pref,
247 .nlmsg_payload = fib6_rule_nlmsg_payload,
248 .nlgroup = RTNLGRP_IPV6_RULE,
249 .policy = fib6_rule_policy,
250 .rules_list = LIST_HEAD_INIT(fib6_rules_ops.rules_list),
251 .owner = THIS_MODULE,
252 .fro_net = &init_net,
253 };
254
255 static int __init fib6_default_rules_init(void)
256 {
257 int err;
258
259 err = fib_default_rule_add(&fib6_rules_ops, 0,
260 RT6_TABLE_LOCAL, FIB_RULE_PERMANENT);
261 if (err < 0)
262 return err;
263 err = fib_default_rule_add(&fib6_rules_ops, 0x7FFE, RT6_TABLE_MAIN, 0);
264 if (err < 0)
265 return err;
266 return 0;
267 }
268
269 int __init fib6_rules_init(void)
270 {
271 int ret;
272
273 ret = fib6_default_rules_init();
274 if (ret)
275 goto out;
276
277 ret = fib_rules_register(&fib6_rules_ops);
278 if (ret)
279 goto out_default_rules_init;
280 out:
281 return ret;
282
283 out_default_rules_init:
284 fib_rules_cleanup_ops(&fib6_rules_ops);
285 goto out;
286 }
287
288 void fib6_rules_cleanup(void)
289 {
290 fib_rules_unregister(&fib6_rules_ops);
291 }
292
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