[NETLINK]: Mark netlink policies const
[linux-2.6.git] / net / ipv6 / fib6_rules.c
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 static 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
43 static 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
53 static LIST_HEAD(fib6_rules);
54
55 struct 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
73 static 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         }
119 again:
120         dst_release(&rt->u.dst);
121         rt = NULL;
122         goto out;
123
124 discard_pkt:
125         dst_hold(&rt->u.dst);
126 out:
127         arg->result = rt;
128         return rt == NULL ? -EAGAIN : 0;
129 }
130
131
132 static 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
160 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
161         FRA_GENERIC_POLICY,
162 };
163
164 static 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;
194 errout:
195         return err;
196 }
197
198 static 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
223 static 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
243 nla_put_failure:
244         return -ENOBUFS;
245 }
246
247 static u32 fib6_rule_default_pref(void)
248 {
249         return 0x3FFF;
250 }
251
252 static 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
258 static 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
275 void __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
283 void fib6_rules_cleanup(void)
284 {
285         fib_rules_unregister(&fib6_rules_ops);
286 }