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21#include <linux/types.h>
22#include <linux/kernel.h>
23#include <linux/netdevice.h>
24#include <linux/netlink.h>
25#include <linux/inetdevice.h>
26#include <linux/init.h>
27#include <linux/list.h>
28#include <linux/rcupdate.h>
29#include <linux/export.h>
30#include <net/ip.h>
31#include <net/route.h>
32#include <net/tcp.h>
33#include <net/ip_fib.h>
34#include <net/fib_rules.h>
35
36struct fib4_rule {
37 struct fib_rule common;
38 u8 dst_len;
39 u8 src_len;
40 u8 tos;
41 __be32 src;
42 __be32 srcmask;
43 __be32 dst;
44 __be32 dstmask;
45#ifdef CONFIG_IP_ROUTE_CLASSID
46 u32 tclassid;
47#endif
48};
49
50static bool fib4_rule_matchall(const struct fib_rule *rule)
51{
52 struct fib4_rule *r = container_of(rule, struct fib4_rule, common);
53
54 if (r->dst_len || r->src_len || r->tos)
55 return false;
56 return fib_rule_matchall(rule);
57}
58
59bool fib4_rule_default(const struct fib_rule *rule)
60{
61 if (!fib4_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL ||
62 rule->l3mdev)
63 return false;
64 if (rule->table != RT_TABLE_LOCAL && rule->table != RT_TABLE_MAIN &&
65 rule->table != RT_TABLE_DEFAULT)
66 return false;
67 return true;
68}
69EXPORT_SYMBOL_GPL(fib4_rule_default);
70
71int __fib_lookup(struct net *net, struct flowi4 *flp,
72 struct fib_result *res, unsigned int flags)
73{
74 struct fib_lookup_arg arg = {
75 .result = res,
76 .flags = flags,
77 };
78 int err;
79
80
81 l3mdev_update_flow(net, flowi4_to_flowi(flp));
82
83 err = fib_rules_lookup(net->ipv4.rules_ops, flowi4_to_flowi(flp), 0, &arg);
84#ifdef CONFIG_IP_ROUTE_CLASSID
85 if (arg.rule)
86 res->tclassid = ((struct fib4_rule *)arg.rule)->tclassid;
87 else
88 res->tclassid = 0;
89#endif
90
91 if (err == -ESRCH)
92 err = -ENETUNREACH;
93
94 return err;
95}
96EXPORT_SYMBOL_GPL(__fib_lookup);
97
98static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp,
99 int flags, struct fib_lookup_arg *arg)
100{
101 int err = -EAGAIN;
102 struct fib_table *tbl;
103 u32 tb_id;
104
105 switch (rule->action) {
106 case FR_ACT_TO_TBL:
107 break;
108
109 case FR_ACT_UNREACHABLE:
110 return -ENETUNREACH;
111
112 case FR_ACT_PROHIBIT:
113 return -EACCES;
114
115 case FR_ACT_BLACKHOLE:
116 default:
117 return -EINVAL;
118 }
119
120 rcu_read_lock();
121
122 tb_id = fib_rule_get_table(rule, arg);
123 tbl = fib_get_table(rule->fr_net, tb_id);
124 if (tbl)
125 err = fib_table_lookup(tbl, &flp->u.ip4,
126 (struct fib_result *)arg->result,
127 arg->flags);
128
129 rcu_read_unlock();
130 return err;
131}
132
133static bool fib4_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)
134{
135 struct fib_result *result = (struct fib_result *) arg->result;
136 struct net_device *dev = NULL;
137
138 if (result->fi)
139 dev = result->fi->fib_dev;
140
141
142
143
144 if (result->prefixlen <= rule->suppress_prefixlen)
145 goto suppress_route;
146
147
148
149
150 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
151 goto suppress_route;
152
153 return false;
154
155suppress_route:
156 if (!(arg->flags & FIB_LOOKUP_NOREF))
157 fib_info_put(result->fi);
158 return true;
159}
160
161static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
162{
163 struct fib4_rule *r = (struct fib4_rule *) rule;
164 struct flowi4 *fl4 = &fl->u.ip4;
165 __be32 daddr = fl4->daddr;
166 __be32 saddr = fl4->saddr;
167
168 if (((saddr ^ r->src) & r->srcmask) ||
169 ((daddr ^ r->dst) & r->dstmask))
170 return 0;
171
172 if (r->tos && (r->tos != fl4->flowi4_tos))
173 return 0;
174
175 return 1;
176}
177
178static struct fib_table *fib_empty_table(struct net *net)
179{
180 u32 id;
181
182 for (id = 1; id <= RT_TABLE_MAX; id++)
183 if (!fib_get_table(net, id))
184 return fib_new_table(net, id);
185 return NULL;
186}
187
188static int call_fib_rule_notifier(struct notifier_block *nb, struct net *net,
189 enum fib_event_type event_type,
190 struct fib_rule *rule)
191{
192 struct fib_rule_notifier_info info = {
193 .rule = rule,
194 };
195
196 return call_fib_notifier(nb, net, event_type, &info.info);
197}
198
199static int call_fib_rule_notifiers(struct net *net,
200 enum fib_event_type event_type,
201 struct fib_rule *rule)
202{
203 struct fib_rule_notifier_info info = {
204 .rule = rule,
205 };
206
207 return call_fib_notifiers(net, event_type, &info.info);
208}
209
210
211void fib_rules_notify(struct net *net, struct notifier_block *nb)
212{
213 struct fib_rules_ops *ops = net->ipv4.rules_ops;
214 struct fib_rule *rule;
215
216 list_for_each_entry_rcu(rule, &ops->rules_list, list)
217 call_fib_rule_notifier(nb, net, FIB_EVENT_RULE_ADD, rule);
218}
219
220static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = {
221 FRA_GENERIC_POLICY,
222 [FRA_FLOW] = { .type = NLA_U32 },
223};
224
225static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
226 struct fib_rule_hdr *frh,
227 struct nlattr **tb)
228{
229 struct net *net = sock_net(skb->sk);
230 int err = -EINVAL;
231 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
232
233 if (frh->tos & ~IPTOS_TOS_MASK)
234 goto errout;
235
236
237 err = fib_unmerge(net);
238 if (err)
239 goto errout;
240
241 if (rule->table == RT_TABLE_UNSPEC && !rule->l3mdev) {
242 if (rule->action == FR_ACT_TO_TBL) {
243 struct fib_table *table;
244
245 table = fib_empty_table(net);
246 if (!table) {
247 err = -ENOBUFS;
248 goto errout;
249 }
250
251 rule->table = table->tb_id;
252 }
253 }
254
255 if (frh->src_len)
256 rule4->src = nla_get_in_addr(tb[FRA_SRC]);
257
258 if (frh->dst_len)
259 rule4->dst = nla_get_in_addr(tb[FRA_DST]);
260
261#ifdef CONFIG_IP_ROUTE_CLASSID
262 if (tb[FRA_FLOW]) {
263 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
264 if (rule4->tclassid)
265 net->ipv4.fib_num_tclassid_users++;
266 }
267#endif
268
269 rule4->src_len = frh->src_len;
270 rule4->srcmask = inet_make_mask(rule4->src_len);
271 rule4->dst_len = frh->dst_len;
272 rule4->dstmask = inet_make_mask(rule4->dst_len);
273 rule4->tos = frh->tos;
274
275 net->ipv4.fib_has_custom_rules = true;
276 call_fib_rule_notifiers(net, FIB_EVENT_RULE_ADD, rule);
277
278 err = 0;
279errout:
280 return err;
281}
282
283static int fib4_rule_delete(struct fib_rule *rule)
284{
285 struct net *net = rule->fr_net;
286 int err;
287
288
289 err = fib_unmerge(net);
290 if (err)
291 goto errout;
292
293#ifdef CONFIG_IP_ROUTE_CLASSID
294 if (((struct fib4_rule *)rule)->tclassid)
295 net->ipv4.fib_num_tclassid_users--;
296#endif
297 net->ipv4.fib_has_custom_rules = true;
298 call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule);
299errout:
300 return err;
301}
302
303static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
304 struct nlattr **tb)
305{
306 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
307
308 if (frh->src_len && (rule4->src_len != frh->src_len))
309 return 0;
310
311 if (frh->dst_len && (rule4->dst_len != frh->dst_len))
312 return 0;
313
314 if (frh->tos && (rule4->tos != frh->tos))
315 return 0;
316
317#ifdef CONFIG_IP_ROUTE_CLASSID
318 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW])))
319 return 0;
320#endif
321
322 if (frh->src_len && (rule4->src != nla_get_in_addr(tb[FRA_SRC])))
323 return 0;
324
325 if (frh->dst_len && (rule4->dst != nla_get_in_addr(tb[FRA_DST])))
326 return 0;
327
328 return 1;
329}
330
331static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
332 struct fib_rule_hdr *frh)
333{
334 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
335
336 frh->dst_len = rule4->dst_len;
337 frh->src_len = rule4->src_len;
338 frh->tos = rule4->tos;
339
340 if ((rule4->dst_len &&
341 nla_put_in_addr(skb, FRA_DST, rule4->dst)) ||
342 (rule4->src_len &&
343 nla_put_in_addr(skb, FRA_SRC, rule4->src)))
344 goto nla_put_failure;
345#ifdef CONFIG_IP_ROUTE_CLASSID
346 if (rule4->tclassid &&
347 nla_put_u32(skb, FRA_FLOW, rule4->tclassid))
348 goto nla_put_failure;
349#endif
350 return 0;
351
352nla_put_failure:
353 return -ENOBUFS;
354}
355
356static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule)
357{
358 return nla_total_size(4)
359 + nla_total_size(4)
360 + nla_total_size(4);
361}
362
363static void fib4_rule_flush_cache(struct fib_rules_ops *ops)
364{
365 rt_cache_flush(ops->fro_net);
366}
367
368static const struct fib_rules_ops __net_initconst fib4_rules_ops_template = {
369 .family = AF_INET,
370 .rule_size = sizeof(struct fib4_rule),
371 .addr_size = sizeof(u32),
372 .action = fib4_rule_action,
373 .suppress = fib4_rule_suppress,
374 .match = fib4_rule_match,
375 .configure = fib4_rule_configure,
376 .delete = fib4_rule_delete,
377 .compare = fib4_rule_compare,
378 .fill = fib4_rule_fill,
379 .nlmsg_payload = fib4_rule_nlmsg_payload,
380 .flush_cache = fib4_rule_flush_cache,
381 .nlgroup = RTNLGRP_IPV4_RULE,
382 .policy = fib4_rule_policy,
383 .owner = THIS_MODULE,
384};
385
386static int fib_default_rules_init(struct fib_rules_ops *ops)
387{
388 int err;
389
390 err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, 0);
391 if (err < 0)
392 return err;
393 err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0);
394 if (err < 0)
395 return err;
396 err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0);
397 if (err < 0)
398 return err;
399 return 0;
400}
401
402int __net_init fib4_rules_init(struct net *net)
403{
404 int err;
405 struct fib_rules_ops *ops;
406
407 ops = fib_rules_register(&fib4_rules_ops_template, net);
408 if (IS_ERR(ops))
409 return PTR_ERR(ops);
410
411 err = fib_default_rules_init(ops);
412 if (err < 0)
413 goto fail;
414 net->ipv4.rules_ops = ops;
415 net->ipv4.fib_has_custom_rules = false;
416 return 0;
417
418fail:
419
420 fib_rules_unregister(ops);
421 return err;
422}
423
424void __net_exit fib4_rules_exit(struct net *net)
425{
426 fib_rules_unregister(net->ipv4.rules_ops);
427}
428
