Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
fib6_rules.c
Go to the documentation of this file.
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 <[email protected]>
13  * Ville Nuorvala <[email protected]>
14  */
15 
16 #include <linux/netdevice.h>
17 #include <linux/export.h>
18 
19 #include <net/fib_rules.h>
20 #include <net/ipv6.h>
21 #include <net/addrconf.h>
22 #include <net/ip6_route.h>
23 #include <net/netlink.h>
24 
25 struct fib6_rule {
26  struct fib_rule common;
27  struct rt6key src;
28  struct rt6key dst;
30 };
31 
32 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
34 {
35  struct fib_lookup_arg arg = {
36  .lookup_ptr = lookup,
37  .flags = FIB_LOOKUP_NOREF,
38  };
39 
40  fib_rules_lookup(net->ipv6.fib6_rules_ops,
41  flowi6_to_flowi(fl6), flags, &arg);
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 
50 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
51  int flags, struct fib_lookup_arg *arg)
52 {
53  struct flowi6 *flp6 = &flp->u.ip6;
54  struct rt6_info *rt = NULL;
55  struct fib6_table *table;
56  struct net *net = rule->fr_net;
58 
59  switch (rule->action) {
60  case FR_ACT_TO_TBL:
61  break;
62  case FR_ACT_UNREACHABLE:
63  rt = net->ipv6.ip6_null_entry;
64  goto discard_pkt;
65  default:
66  case FR_ACT_BLACKHOLE:
67  rt = net->ipv6.ip6_blk_hole_entry;
68  goto discard_pkt;
69  case FR_ACT_PROHIBIT:
70  rt = net->ipv6.ip6_prohibit_entry;
71  goto discard_pkt;
72  }
73 
74  table = fib6_get_table(net, rule->table);
75  if (table)
76  rt = lookup(net, table, flp6, flags);
77 
78  if (rt != net->ipv6.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 
89  if (ipv6_dev_get_saddr(net,
90  ip6_dst_idev(&rt->dst)->dev,
91  &flp6->daddr,
92  rt6_flags2srcprefs(flags),
93  &saddr))
94  goto again;
95  if (!ipv6_prefix_equal(&saddr, &r->src.addr,
96  r->src.plen))
97  goto again;
98  flp6->saddr = saddr;
99  }
100  goto out;
101  }
102 again:
103  dst_release(&rt->dst);
104  rt = NULL;
105  goto out;
106 
107 discard_pkt:
108  dst_hold(&rt->dst);
109 out:
110  arg->result = rt;
111  return rt == NULL ? -EAGAIN : 0;
112 }
113 
114 
115 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
116 {
117  struct fib6_rule *r = (struct fib6_rule *) rule;
118  struct flowi6 *fl6 = &fl->u.ip6;
119 
120  if (r->dst.plen &&
121  !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen))
122  return 0;
123 
124  /*
125  * If FIB_RULE_FIND_SADDR is set and we do not have a
126  * source address for the traffic, we defer check for
127  * source address.
128  */
129  if (r->src.plen) {
130  if (flags & RT6_LOOKUP_F_HAS_SADDR) {
131  if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr,
132  r->src.plen))
133  return 0;
134  } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
135  return 0;
136  }
137 
138  if (r->tclass && r->tclass != ((ntohl(fl6->flowlabel) >> 20) & 0xff))
139  return 0;
140 
141  return 1;
142 }
143 
144 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
146 };
147 
148 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
149  struct fib_rule_hdr *frh,
150  struct nlattr **tb)
151 {
152  int err = -EINVAL;
153  struct net *net = sock_net(skb->sk);
154  struct fib6_rule *rule6 = (struct fib6_rule *) rule;
155 
156  if (rule->action == FR_ACT_TO_TBL) {
157  if (rule->table == RT6_TABLE_UNSPEC)
158  goto errout;
159 
160  if (fib6_new_table(net, rule->table) == NULL) {
161  err = -ENOBUFS;
162  goto errout;
163  }
164  }
165 
166  if (frh->src_len)
167  nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
168  sizeof(struct in6_addr));
169 
170  if (frh->dst_len)
171  nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
172  sizeof(struct in6_addr));
173 
174  rule6->src.plen = frh->src_len;
175  rule6->dst.plen = frh->dst_len;
176  rule6->tclass = frh->tos;
177 
178  err = 0;
179 errout:
180  return err;
181 }
182 
183 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
184  struct nlattr **tb)
185 {
186  struct fib6_rule *rule6 = (struct fib6_rule *) rule;
187 
188  if (frh->src_len && (rule6->src.plen != frh->src_len))
189  return 0;
190 
191  if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
192  return 0;
193 
194  if (frh->tos && (rule6->tclass != frh->tos))
195  return 0;
196 
197  if (frh->src_len &&
198  nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
199  return 0;
200 
201  if (frh->dst_len &&
202  nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
203  return 0;
204 
205  return 1;
206 }
207 
208 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
209  struct fib_rule_hdr *frh)
210 {
211  struct fib6_rule *rule6 = (struct fib6_rule *) rule;
212 
213  frh->dst_len = rule6->dst.plen;
214  frh->src_len = rule6->src.plen;
215  frh->tos = rule6->tclass;
216 
217  if ((rule6->dst.plen &&
218  nla_put(skb, FRA_DST, sizeof(struct in6_addr),
219  &rule6->dst.addr)) ||
220  (rule6->src.plen &&
221  nla_put(skb, FRA_SRC, sizeof(struct in6_addr),
222  &rule6->src.addr)))
223  goto nla_put_failure;
224  return 0;
225 
226 nla_put_failure:
227  return -ENOBUFS;
228 }
229 
230 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
231 {
232  return 0x3FFF;
233 }
234 
235 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
236 {
237  return nla_total_size(16) /* dst */
238  + nla_total_size(16); /* src */
239 }
240 
241 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = {
242  .family = AF_INET6,
243  .rule_size = sizeof(struct fib6_rule),
244  .addr_size = sizeof(struct in6_addr),
245  .action = fib6_rule_action,
246  .match = fib6_rule_match,
247  .configure = fib6_rule_configure,
248  .compare = fib6_rule_compare,
249  .fill = fib6_rule_fill,
250  .default_pref = fib6_rule_default_pref,
251  .nlmsg_payload = fib6_rule_nlmsg_payload,
252  .nlgroup = RTNLGRP_IPV6_RULE,
253  .policy = fib6_rule_policy,
254  .owner = THIS_MODULE,
255  .fro_net = &init_net,
256 };
257 
258 static int __net_init fib6_rules_net_init(struct net *net)
259 {
260  struct fib_rules_ops *ops;
261  int err = -ENOMEM;
262 
263  ops = fib_rules_register(&fib6_rules_ops_template, net);
264  if (IS_ERR(ops))
265  return PTR_ERR(ops);
266  net->ipv6.fib6_rules_ops = ops;
267 
268 
269  err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
270  RT6_TABLE_LOCAL, 0);
271  if (err)
272  goto out_fib6_rules_ops;
273 
274  err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
275  0x7FFE, RT6_TABLE_MAIN, 0);
276  if (err)
277  goto out_fib6_rules_ops;
278 
279 out:
280  return err;
281 
282 out_fib6_rules_ops:
284  goto out;
285 }
286 
287 static void __net_exit fib6_rules_net_exit(struct net *net)
288 {
289  fib_rules_unregister(net->ipv6.fib6_rules_ops);
290 }
291 
292 static struct pernet_operations fib6_rules_net_ops = {
293  .init = fib6_rules_net_init,
294  .exit = fib6_rules_net_exit,
295 };
296 
298 {
299  return register_pernet_subsys(&fib6_rules_net_ops);
300 }
301 
302 
304 {
305  unregister_pernet_subsys(&fib6_rules_net_ops);
306 }