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