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 <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
36 struct 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
50 #ifdef CONFIG_IP_ROUTE_CLASSID
fib_rules_tclass(const struct fib_result * res)51 u32 fib_rules_tclass(const struct fib_result *res)
52 {
53 return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0;
54 }
55 #endif
56
fib_lookup(struct net * net,struct flowi4 * flp,struct fib_result * res)57 int fib_lookup(struct net *net, struct flowi4 *flp, struct fib_result *res)
58 {
59 struct fib_lookup_arg arg = {
60 .result = res,
61 .flags = FIB_LOOKUP_NOREF,
62 };
63 int err;
64
65 err = fib_rules_lookup(net->ipv4.rules_ops, flowi4_to_flowi(flp), 0, &arg);
66 res->r = arg.rule;
67
68 return err;
69 }
70 EXPORT_SYMBOL_GPL(fib_lookup);
71
fib4_rule_action(struct fib_rule * rule,struct flowi * flp,int flags,struct fib_lookup_arg * arg)72 static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp,
73 int flags, struct fib_lookup_arg *arg)
74 {
75 int err = -EAGAIN;
76 struct fib_table *tbl;
77
78 switch (rule->action) {
79 case FR_ACT_TO_TBL:
80 break;
81
82 case FR_ACT_UNREACHABLE:
83 err = -ENETUNREACH;
84 goto errout;
85
86 case FR_ACT_PROHIBIT:
87 err = -EACCES;
88 goto errout;
89
90 case FR_ACT_BLACKHOLE:
91 default:
92 err = -EINVAL;
93 goto errout;
94 }
95
96 tbl = fib_get_table(rule->fr_net, rule->table);
97 if (!tbl)
98 goto errout;
99
100 err = fib_table_lookup(tbl, &flp->u.ip4, (struct fib_result *) arg->result, arg->flags);
101 if (err > 0)
102 err = -EAGAIN;
103 errout:
104 return err;
105 }
106
107
fib4_rule_match(struct fib_rule * rule,struct flowi * fl,int flags)108 static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
109 {
110 struct fib4_rule *r = (struct fib4_rule *) rule;
111 struct flowi4 *fl4 = &fl->u.ip4;
112 __be32 daddr = fl4->daddr;
113 __be32 saddr = fl4->saddr;
114
115 if (((saddr ^ r->src) & r->srcmask) ||
116 ((daddr ^ r->dst) & r->dstmask))
117 return 0;
118
119 if (r->tos && (r->tos != fl4->flowi4_tos))
120 return 0;
121
122 return 1;
123 }
124
fib_empty_table(struct net * net)125 static struct fib_table *fib_empty_table(struct net *net)
126 {
127 u32 id;
128
129 for (id = 1; id <= RT_TABLE_MAX; id++)
130 if (fib_get_table(net, id) == NULL)
131 return fib_new_table(net, id);
132 return NULL;
133 }
134
135 static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = {
136 FRA_GENERIC_POLICY,
137 [FRA_FLOW] = { .type = NLA_U32 },
138 };
139
fib4_rule_configure(struct fib_rule * rule,struct sk_buff * skb,struct fib_rule_hdr * frh,struct nlattr ** tb)140 static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
141 struct fib_rule_hdr *frh,
142 struct nlattr **tb)
143 {
144 struct net *net = sock_net(skb->sk);
145 int err = -EINVAL;
146 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
147
148 if (frh->tos & ~IPTOS_TOS_MASK)
149 goto errout;
150
151 if (rule->table == RT_TABLE_UNSPEC) {
152 if (rule->action == FR_ACT_TO_TBL) {
153 struct fib_table *table;
154
155 table = fib_empty_table(net);
156 if (table == NULL) {
157 err = -ENOBUFS;
158 goto errout;
159 }
160
161 rule->table = table->tb_id;
162 }
163 }
164
165 if (frh->src_len)
166 rule4->src = nla_get_be32(tb[FRA_SRC]);
167
168 if (frh->dst_len)
169 rule4->dst = nla_get_be32(tb[FRA_DST]);
170
171 #ifdef CONFIG_IP_ROUTE_CLASSID
172 if (tb[FRA_FLOW])
173 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
174 #endif
175
176 rule4->src_len = frh->src_len;
177 rule4->srcmask = inet_make_mask(rule4->src_len);
178 rule4->dst_len = frh->dst_len;
179 rule4->dstmask = inet_make_mask(rule4->dst_len);
180 rule4->tos = frh->tos;
181
182 err = 0;
183 errout:
184 return err;
185 }
186
fib4_rule_compare(struct fib_rule * rule,struct fib_rule_hdr * frh,struct nlattr ** tb)187 static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
188 struct nlattr **tb)
189 {
190 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
191
192 if (frh->src_len && (rule4->src_len != frh->src_len))
193 return 0;
194
195 if (frh->dst_len && (rule4->dst_len != frh->dst_len))
196 return 0;
197
198 if (frh->tos && (rule4->tos != frh->tos))
199 return 0;
200
201 #ifdef CONFIG_IP_ROUTE_CLASSID
202 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW])))
203 return 0;
204 #endif
205
206 if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC])))
207 return 0;
208
209 if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST])))
210 return 0;
211
212 return 1;
213 }
214
fib4_rule_fill(struct fib_rule * rule,struct sk_buff * skb,struct fib_rule_hdr * frh)215 static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
216 struct fib_rule_hdr *frh)
217 {
218 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
219
220 frh->dst_len = rule4->dst_len;
221 frh->src_len = rule4->src_len;
222 frh->tos = rule4->tos;
223
224 if (rule4->dst_len)
225 NLA_PUT_BE32(skb, FRA_DST, rule4->dst);
226
227 if (rule4->src_len)
228 NLA_PUT_BE32(skb, FRA_SRC, rule4->src);
229
230 #ifdef CONFIG_IP_ROUTE_CLASSID
231 if (rule4->tclassid)
232 NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid);
233 #endif
234 return 0;
235
236 nla_put_failure:
237 return -ENOBUFS;
238 }
239
fib4_rule_nlmsg_payload(struct fib_rule * rule)240 static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule)
241 {
242 return nla_total_size(4) /* dst */
243 + nla_total_size(4) /* src */
244 + nla_total_size(4); /* flow */
245 }
246
fib4_rule_flush_cache(struct fib_rules_ops * ops)247 static void fib4_rule_flush_cache(struct fib_rules_ops *ops)
248 {
249 rt_cache_flush(ops->fro_net, -1);
250 }
251
252 static const struct fib_rules_ops __net_initdata fib4_rules_ops_template = {
253 .family = AF_INET,
254 .rule_size = sizeof(struct fib4_rule),
255 .addr_size = sizeof(u32),
256 .action = fib4_rule_action,
257 .match = fib4_rule_match,
258 .configure = fib4_rule_configure,
259 .compare = fib4_rule_compare,
260 .fill = fib4_rule_fill,
261 .default_pref = fib_default_rule_pref,
262 .nlmsg_payload = fib4_rule_nlmsg_payload,
263 .flush_cache = fib4_rule_flush_cache,
264 .nlgroup = RTNLGRP_IPV4_RULE,
265 .policy = fib4_rule_policy,
266 .owner = THIS_MODULE,
267 };
268
fib_default_rules_init(struct fib_rules_ops * ops)269 static int fib_default_rules_init(struct fib_rules_ops *ops)
270 {
271 int err;
272
273 err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, 0);
274 if (err < 0)
275 return err;
276 err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0);
277 if (err < 0)
278 return err;
279 err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0);
280 if (err < 0)
281 return err;
282 return 0;
283 }
284
fib4_rules_init(struct net * net)285 int __net_init fib4_rules_init(struct net *net)
286 {
287 int err;
288 struct fib_rules_ops *ops;
289
290 ops = fib_rules_register(&fib4_rules_ops_template, net);
291 if (IS_ERR(ops))
292 return PTR_ERR(ops);
293
294 err = fib_default_rules_init(ops);
295 if (err < 0)
296 goto fail;
297 net->ipv4.rules_ops = ops;
298 return 0;
299
300 fail:
301 /* also cleans all rules already added */
302 fib_rules_unregister(ops);
303 return err;
304 }
305
fib4_rules_exit(struct net * net)306 void __net_exit fib4_rules_exit(struct net *net)
307 {
308 fib_rules_unregister(net->ipv4.rules_ops);
309 }
310