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