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