1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * IPv4 Forwarding Information Base: policy rules.
7 *
8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
9 * Thomas Graf <tgraf@suug.ch>
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
15 *
16 * Fixes:
17 * Rani Assaf : local_rule cannot be deleted
18 * Marc Boucher : routing by fwmark
19 */
20
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 <net/ip.h>
30 #include <net/route.h>
31 #include <net/tcp.h>
32 #include <net/ip_fib.h>
33 #include <net/fib_rules.h>
34
35 struct fib4_rule
36 {
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_NET_CLS_ROUTE
46 u32 tclassid;
47 #endif
48 };
49
50 #ifdef CONFIG_NET_CLS_ROUTE
51 u32 fib_rules_tclass(struct fib_result *res)
52 {
53 return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0;
54 }
55 #endif
56
57 int fib_lookup(struct net *net, struct flowi *flp, struct fib_result *res)
58 {
59 struct fib_lookup_arg arg = {
60 .result = res,
61 };
62 int err;
63
64 err = fib_rules_lookup(net->ipv4.rules_ops, flp, 0, &arg);
65 res->r = arg.rule;
66
67 return err;
68 }
69
70 static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp,
71 int flags, struct fib_lookup_arg *arg)
72 {
73 int err = -EAGAIN;
74 struct fib_table *tbl;
75
76 switch (rule->action) {
77 case FR_ACT_TO_TBL:
78 break;
79
80 case FR_ACT_UNREACHABLE:
81 err = -ENETUNREACH;
82 goto errout;
83
84 case FR_ACT_PROHIBIT:
85 err = -EACCES;
86 goto errout;
87
88 case FR_ACT_BLACKHOLE:
89 default:
90 err = -EINVAL;
91 goto errout;
92 }
93
94 if ((tbl = fib_get_table(rule->fr_net, rule->table)) == NULL)
95 goto errout;
96
97 err = tbl->tb_lookup(tbl, flp, (struct fib_result *) arg->result);
98 if (err > 0)
99 err = -EAGAIN;
100 errout:
101 return err;
102 }
103
104
105 static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
106 {
107 struct fib4_rule *r = (struct fib4_rule *) rule;
108 __be32 daddr = fl->fl4_dst;
109 __be32 saddr = fl->fl4_src;
110
111 if (((saddr ^ r->src) & r->srcmask) ||
112 ((daddr ^ r->dst) & r->dstmask))
113 return 0;
114
115 if (r->tos && (r->tos != fl->fl4_tos))
116 return 0;
117
118 return 1;
119 }
120
121 static struct fib_table *fib_empty_table(struct net *net)
122 {
123 u32 id;
124
125 for (id = 1; id <= RT_TABLE_MAX; id++)
126 if (fib_get_table(net, id) == NULL)
127 return fib_new_table(net, id);
128 return NULL;
129 }
130
131 static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = {
132 FRA_GENERIC_POLICY,
133 [FRA_FLOW] = { .type = NLA_U32 },
134 };
135
136 static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
137 struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
138 struct nlattr **tb)
139 {
140 struct net *net = skb->sk->sk_net;
141 int err = -EINVAL;
142 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
143
144 if (frh->tos & ~IPTOS_TOS_MASK)
145 goto errout;
146
147 if (rule->table == RT_TABLE_UNSPEC) {
148 if (rule->action == FR_ACT_TO_TBL) {
149 struct fib_table *table;
150
151 table = fib_empty_table(net);
152 if (table == NULL) {
153 err = -ENOBUFS;
154 goto errout;
155 }
156
157 rule->table = table->tb_id;
158 }
159 }
160
161 if (frh->src_len)
162 rule4->src = nla_get_be32(tb[FRA_SRC]);
163
164 if (frh->dst_len)
165 rule4->dst = nla_get_be32(tb[FRA_DST]);
166
167 #ifdef CONFIG_NET_CLS_ROUTE
168 if (tb[FRA_FLOW])
169 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
170 #endif
171
172 rule4->src_len = frh->src_len;
173 rule4->srcmask = inet_make_mask(rule4->src_len);
174 rule4->dst_len = frh->dst_len;
175 rule4->dstmask = inet_make_mask(rule4->dst_len);
176 rule4->tos = frh->tos;
177
178 err = 0;
179 errout:
180 return err;
181 }
182
183 static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
184 struct nlattr **tb)
185 {
186 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
187
188 if (frh->src_len && (rule4->src_len != frh->src_len))
189 return 0;
190
191 if (frh->dst_len && (rule4->dst_len != frh->dst_len))
192 return 0;
193
194 if (frh->tos && (rule4->tos != frh->tos))
195 return 0;
196
197 #ifdef CONFIG_NET_CLS_ROUTE
198 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW])))
199 return 0;
200 #endif
201
202 if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC])))
203 return 0;
204
205 if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST])))
206 return 0;
207
208 return 1;
209 }
210
211 static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
212 struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
213 {
214 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
215
216 frh->family = AF_INET;
217 frh->dst_len = rule4->dst_len;
218 frh->src_len = rule4->src_len;
219 frh->tos = rule4->tos;
220
221 if (rule4->dst_len)
222 NLA_PUT_BE32(skb, FRA_DST, rule4->dst);
223
224 if (rule4->src_len)
225 NLA_PUT_BE32(skb, FRA_SRC, rule4->src);
226
227 #ifdef CONFIG_NET_CLS_ROUTE
228 if (rule4->tclassid)
229 NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid);
230 #endif
231 return 0;
232
233 nla_put_failure:
234 return -ENOBUFS;
235 }
236
237 static u32 fib4_rule_default_pref(struct fib_rules_ops *ops)
238 {
239 struct list_head *pos;
240 struct fib_rule *rule;
241
242 if (!list_empty(&ops->rules_list)) {
243 pos = ops->rules_list.next;
244 if (pos->next != &ops->rules_list) {
245 rule = list_entry(pos->next, struct fib_rule, list);
246 if (rule->pref)
247 return rule->pref - 1;
248 }
249 }
250
251 return 0;
252 }
253
254 static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule)
255 {
256 return nla_total_size(4) /* dst */
257 + nla_total_size(4) /* src */
258 + nla_total_size(4); /* flow */
259 }
260
261 static void fib4_rule_flush_cache(void)
262 {
263 rt_cache_flush(-1);
264 }
265
266 static struct fib_rules_ops fib4_rules_ops_template = {
267 .family = AF_INET,
268 .rule_size = sizeof(struct fib4_rule),
269 .addr_size = sizeof(u32),
270 .action = fib4_rule_action,
271 .match = fib4_rule_match,
272 .configure = fib4_rule_configure,
273 .compare = fib4_rule_compare,
274 .fill = fib4_rule_fill,
275 .default_pref = fib4_rule_default_pref,
276 .nlmsg_payload = fib4_rule_nlmsg_payload,
277 .flush_cache = fib4_rule_flush_cache,
278 .nlgroup = RTNLGRP_IPV4_RULE,
279 .policy = fib4_rule_policy,
280 .owner = THIS_MODULE,
281 };
282
283 static int fib_default_rules_init(struct fib_rules_ops *ops)
284 {
285 int err;
286
287 err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, FIB_RULE_PERMANENT);
288 if (err < 0)
289 return err;
290 err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0);
291 if (err < 0)
292 return err;
293 err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0);
294 if (err < 0)
295 return err;
296 return 0;
297 }
298
299 int __net_init fib4_rules_init(struct net *net)
300 {
301 int err;
302 struct fib_rules_ops *ops;
303
304 ops = kmemdup(&fib4_rules_ops_template, sizeof(*ops), GFP_KERNEL);
305 if (ops == NULL)
306 return -ENOMEM;
307 INIT_LIST_HEAD(&ops->rules_list);
308 ops->fro_net = net;
309
310 fib_rules_register(ops);
311
312 err = fib_default_rules_init(ops);
313 if (err < 0)
314 goto fail;
315 net->ipv4.rules_ops = ops;
316 return 0;
317
318 fail:
319 /* also cleans all rules already added */
320 fib_rules_unregister(ops);
321 kfree(ops);
322 return err;
323 }
324
325 void __net_exit fib4_rules_exit(struct net *net)
326 {
327 fib_rules_unregister(net->ipv4.rules_ops);
328 kfree(net->ipv4.rules_ops);
329 }
330
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