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
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
50static bool fib4_rule_matchall(const struct fib_rule *rule)
51{
52 struct fib4_rule *r = container_of(rule, struct fib4_rule, common);
53
54 if (r->dst_len || r->src_len || r->tos)
55 return false;
56 return fib_rule_matchall(rule);
57}
58
59bool fib4_rule_default(const struct fib_rule *rule)
60{
61 if (!fib4_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL ||
62 rule->l3mdev)
63 return false;
64 if (rule->table != RT_TABLE_LOCAL && rule->table != RT_TABLE_MAIN &&
65 rule->table != RT_TABLE_DEFAULT)
66 return false;
67 return true;
68}
69EXPORT_SYMBOL_GPL(fib4_rule_default);
70
71int fib4_rules_dump(struct net *net, struct notifier_block *nb)
72{
73 return fib_rules_dump(net, nb, AF_INET);
74}
75
76unsigned int fib4_rules_seq_read(struct net *net)
77{
78 return fib_rules_seq_read(net, AF_INET);
79}
80
81int __fib_lookup(struct net *net, struct flowi4 *flp,
82 struct fib_result *res, unsigned int flags)
83{
84 struct fib_lookup_arg arg = {
85 .result = res,
86 .flags = flags,
87 };
88 int err;
89
90 /* update flow if oif or iif point to device enslaved to l3mdev */
91 l3mdev_update_flow(net, flowi4_to_flowi(flp));
92
93 err = fib_rules_lookup(net->ipv4.rules_ops, flowi4_to_flowi(flp), 0, &arg);
94#ifdef CONFIG_IP_ROUTE_CLASSID
95 if (arg.rule)
96 res->tclassid = ((struct fib4_rule *)arg.rule)->tclassid;
97 else
98 res->tclassid = 0;
99#endif
100
101 if (err == -ESRCH)
102 err = -ENETUNREACH;
103
104 return err;
105}
106EXPORT_SYMBOL_GPL(__fib_lookup);
107
108static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp,
109 int flags, struct fib_lookup_arg *arg)
110{
111 int err = -EAGAIN;
112 struct fib_table *tbl;
113 u32 tb_id;
114
115 switch (rule->action) {
116 case FR_ACT_TO_TBL:
117 break;
118
119 case FR_ACT_UNREACHABLE:
120 return -ENETUNREACH;
121
122 case FR_ACT_PROHIBIT:
123 return -EACCES;
124
125 case FR_ACT_BLACKHOLE:
126 default:
127 return -EINVAL;
128 }
129
130 rcu_read_lock();
131
132 tb_id = fib_rule_get_table(rule, arg);
133 tbl = fib_get_table(rule->fr_net, tb_id);
134 if (tbl)
135 err = fib_table_lookup(tbl, &flp->u.ip4,
136 (struct fib_result *)arg->result,
137 arg->flags);
138
139 rcu_read_unlock();
140 return err;
141}
142
143static bool fib4_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)
144{
145 struct fib_result *result = (struct fib_result *) arg->result;
146 struct net_device *dev = NULL;
147
148 if (result->fi)
149 dev = result->fi->fib_dev;
150
151 /* do not accept result if the route does
152 * not meet the required prefix length
153 */
154 if (result->prefixlen <= rule->suppress_prefixlen)
155 goto suppress_route;
156
157 /* do not accept result if the route uses a device
158 * belonging to a forbidden interface group
159 */
160 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
161 goto suppress_route;
162
163 return false;
164
165suppress_route:
166 if (!(arg->flags & FIB_LOOKUP_NOREF))
167 fib_info_put(result->fi);
168 return true;
169}
170
171static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
172{
173 struct fib4_rule *r = (struct fib4_rule *) rule;
174 struct flowi4 *fl4 = &fl->u.ip4;
175 __be32 daddr = fl4->daddr;
176 __be32 saddr = fl4->saddr;
177
178 if (((saddr ^ r->src) & r->srcmask) ||
179 ((daddr ^ r->dst) & r->dstmask))
180 return 0;
181
182 if (r->tos && (r->tos != fl4->flowi4_tos))
183 return 0;
184
185 if (rule->ip_proto && (rule->ip_proto != fl4->flowi4_proto))
186 return 0;
187
188 if (fib_rule_port_range_set(&rule->sport_range) &&
189 !fib_rule_port_inrange(&rule->sport_range, fl4->fl4_sport))
190 return 0;
191
192 if (fib_rule_port_range_set(&rule->dport_range) &&
193 !fib_rule_port_inrange(&rule->dport_range, fl4->fl4_dport))
194 return 0;
195
196 return 1;
197}
198
199static struct fib_table *fib_empty_table(struct net *net)
200{
201 u32 id;
202
203 for (id = 1; id <= RT_TABLE_MAX; id++)
204 if (!fib_get_table(net, id))
205 return fib_new_table(net, id);
206 return NULL;
207}
208
209static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = {
210 FRA_GENERIC_POLICY,
211 [FRA_FLOW] = { .type = NLA_U32 },
212};
213
214static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
215 struct fib_rule_hdr *frh,
216 struct nlattr **tb,
217 struct netlink_ext_ack *extack)
218{
219 struct net *net = sock_net(skb->sk);
220 int err = -EINVAL;
221 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
222
223 if (frh->tos & ~IPTOS_TOS_MASK) {
224 NL_SET_ERR_MSG(extack, "Invalid tos");
225 goto errout;
226 }
227
228 /* split local/main if they are not already split */
229 err = fib_unmerge(net);
230 if (err)
231 goto errout;
232
233 if (rule->table == RT_TABLE_UNSPEC && !rule->l3mdev) {
234 if (rule->action == FR_ACT_TO_TBL) {
235 struct fib_table *table;
236
237 table = fib_empty_table(net);
238 if (!table) {
239 err = -ENOBUFS;
240 goto errout;
241 }
242
243 rule->table = table->tb_id;
244 }
245 }
246
247 if (frh->src_len)
248 rule4->src = nla_get_in_addr(tb[FRA_SRC]);
249
250 if (frh->dst_len)
251 rule4->dst = nla_get_in_addr(tb[FRA_DST]);
252
253#ifdef CONFIG_IP_ROUTE_CLASSID
254 if (tb[FRA_FLOW]) {
255 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
256 if (rule4->tclassid)
257 net->ipv4.fib_num_tclassid_users++;
258 }
259#endif
260
261 if (fib_rule_requires_fldissect(rule))
262 net->ipv4.fib_rules_require_fldissect++;
263
264 rule4->src_len = frh->src_len;
265 rule4->srcmask = inet_make_mask(rule4->src_len);
266 rule4->dst_len = frh->dst_len;
267 rule4->dstmask = inet_make_mask(rule4->dst_len);
268 rule4->tos = frh->tos;
269
270 net->ipv4.fib_has_custom_rules = true;
271
272 err = 0;
273errout:
274 return err;
275}
276
277static int fib4_rule_delete(struct fib_rule *rule)
278{
279 struct net *net = rule->fr_net;
280 int err;
281
282 /* split local/main if they are not already split */
283 err = fib_unmerge(net);
284 if (err)
285 goto errout;
286
287#ifdef CONFIG_IP_ROUTE_CLASSID
288 if (((struct fib4_rule *)rule)->tclassid)
289 net->ipv4.fib_num_tclassid_users--;
290#endif
291 net->ipv4.fib_has_custom_rules = true;
292
293 if (net->ipv4.fib_rules_require_fldissect &&
294 fib_rule_requires_fldissect(rule))
295 net->ipv4.fib_rules_require_fldissect--;
296errout:
297 return err;
298}
299
300static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
301 struct nlattr **tb)
302{
303 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
304
305 if (frh->src_len && (rule4->src_len != frh->src_len))
306 return 0;
307
308 if (frh->dst_len && (rule4->dst_len != frh->dst_len))
309 return 0;
310
311 if (frh->tos && (rule4->tos != frh->tos))
312 return 0;
313
314#ifdef CONFIG_IP_ROUTE_CLASSID
315 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW])))
316 return 0;
317#endif
318
319 if (frh->src_len && (rule4->src != nla_get_in_addr(tb[FRA_SRC])))
320 return 0;
321
322 if (frh->dst_len && (rule4->dst != nla_get_in_addr(tb[FRA_DST])))
323 return 0;
324
325 return 1;
326}
327
328static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
329 struct fib_rule_hdr *frh)
330{
331 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
332
333 frh->dst_len = rule4->dst_len;
334 frh->src_len = rule4->src_len;
335 frh->tos = rule4->tos;
336
337 if ((rule4->dst_len &&
338 nla_put_in_addr(skb, FRA_DST, rule4->dst)) ||
339 (rule4->src_len &&
340 nla_put_in_addr(skb, FRA_SRC, rule4->src)))
341 goto nla_put_failure;
342#ifdef CONFIG_IP_ROUTE_CLASSID
343 if (rule4->tclassid &&
344 nla_put_u32(skb, FRA_FLOW, rule4->tclassid))
345 goto nla_put_failure;
346#endif
347 return 0;
348
349nla_put_failure:
350 return -ENOBUFS;
351}
352
353static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule)
354{
355 return nla_total_size(4) /* dst */
356 + nla_total_size(4) /* src */
357 + nla_total_size(4); /* flow */
358}
359
360static void fib4_rule_flush_cache(struct fib_rules_ops *ops)
361{
362 rt_cache_flush(ops->fro_net);
363}
364
365static const struct fib_rules_ops __net_initconst fib4_rules_ops_template = {
366 .family = AF_INET,
367 .rule_size = sizeof(struct fib4_rule),
368 .addr_size = sizeof(u32),
369 .action = fib4_rule_action,
370 .suppress = fib4_rule_suppress,
371 .match = fib4_rule_match,
372 .configure = fib4_rule_configure,
373 .delete = fib4_rule_delete,
374 .compare = fib4_rule_compare,
375 .fill = fib4_rule_fill,
376 .nlmsg_payload = fib4_rule_nlmsg_payload,
377 .flush_cache = fib4_rule_flush_cache,
378 .nlgroup = RTNLGRP_IPV4_RULE,
379 .policy = fib4_rule_policy,
380 .owner = THIS_MODULE,
381};
382
383static int fib_default_rules_init(struct fib_rules_ops *ops)
384{
385 int err;
386
387 err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, 0);
388 if (err < 0)
389 return err;
390 err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0);
391 if (err < 0)
392 return err;
393 err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0);
394 if (err < 0)
395 return err;
396 return 0;
397}
398
399int __net_init fib4_rules_init(struct net *net)
400{
401 int err;
402 struct fib_rules_ops *ops;
403
404 ops = fib_rules_register(&fib4_rules_ops_template, net);
405 if (IS_ERR(ops))
406 return PTR_ERR(ops);
407
408 err = fib_default_rules_init(ops);
409 if (err < 0)
410 goto fail;
411 net->ipv4.rules_ops = ops;
412 net->ipv4.fib_has_custom_rules = false;
413 net->ipv4.fib_rules_require_fldissect = 0;
414 return 0;
415
416fail:
417 /* also cleans all rules already added */
418 fib_rules_unregister(ops);
419 return err;
420}
421
422void __net_exit fib4_rules_exit(struct net *net)
423{
424 fib_rules_unregister(net->ipv4.rules_ops);
425}
426