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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
35struct fib4_rule {
36 struct fib_rule common;
37 u8 dst_len;
38 u8 src_len;
39 u8 tos;
40 __be32 src;
41 __be32 srcmask;
42 __be32 dst;
43 __be32 dstmask;
44#ifdef CONFIG_IP_ROUTE_CLASSID
45 u32 tclassid;
46#endif
47};
48
49#ifdef CONFIG_IP_ROUTE_CLASSID
50u32 fib_rules_tclass(const struct fib_result *res)
51{
52 return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0;
53}
54#endif
55
56int fib_lookup(struct net *net, struct flowi4 *flp, struct fib_result *res)
57{
58 struct fib_lookup_arg arg = {
59 .result = res,
60 .flags = FIB_LOOKUP_NOREF,
61 };
62 int err;
63
64 err = fib_rules_lookup(net->ipv4.rules_ops, flowi4_to_flowi(flp), 0, &arg);
65 res->r = arg.rule;
66
67 return err;
68}
69
70static 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 tbl = fib_get_table(rule->fr_net, rule->table);
95 if (!tbl)
96 goto errout;
97
98 err = fib_table_lookup(tbl, &flp->u.ip4, (struct fib_result *) arg->result, arg->flags);
99 if (err > 0)
100 err = -EAGAIN;
101errout:
102 return err;
103}
104
105
106static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
107{
108 struct fib4_rule *r = (struct fib4_rule *) rule;
109 struct flowi4 *fl4 = &fl->u.ip4;
110 __be32 daddr = fl4->daddr;
111 __be32 saddr = fl4->saddr;
112
113 if (((saddr ^ r->src) & r->srcmask) ||
114 ((daddr ^ r->dst) & r->dstmask))
115 return 0;
116
117 if (r->tos && (r->tos != fl4->flowi4_tos))
118 return 0;
119
120 return 1;
121}
122
123static struct fib_table *fib_empty_table(struct net *net)
124{
125 u32 id;
126
127 for (id = 1; id <= RT_TABLE_MAX; id++)
128 if (fib_get_table(net, id) == NULL)
129 return fib_new_table(net, id);
130 return NULL;
131}
132
133static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = {
134 FRA_GENERIC_POLICY,
135 [FRA_FLOW] = { .type = NLA_U32 },
136};
137
138static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
139 struct fib_rule_hdr *frh,
140 struct nlattr **tb)
141{
142 struct net *net = sock_net(skb->sk);
143 int err = -EINVAL;
144 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
145
146 if (frh->tos & ~IPTOS_TOS_MASK)
147 goto errout;
148
149 if (rule->table == RT_TABLE_UNSPEC) {
150 if (rule->action == FR_ACT_TO_TBL) {
151 struct fib_table *table;
152
153 table = fib_empty_table(net);
154 if (table == NULL) {
155 err = -ENOBUFS;
156 goto errout;
157 }
158
159 rule->table = table->tb_id;
160 }
161 }
162
163 if (frh->src_len)
164 rule4->src = nla_get_be32(tb[FRA_SRC]);
165
166 if (frh->dst_len)
167 rule4->dst = nla_get_be32(tb[FRA_DST]);
168
169#ifdef CONFIG_IP_ROUTE_CLASSID
170 if (tb[FRA_FLOW])
171 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
172#endif
173
174 rule4->src_len = frh->src_len;
175 rule4->srcmask = inet_make_mask(rule4->src_len);
176 rule4->dst_len = frh->dst_len;
177 rule4->dstmask = inet_make_mask(rule4->dst_len);
178 rule4->tos = frh->tos;
179
180 err = 0;
181errout:
182 return err;
183}
184
185static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
186 struct nlattr **tb)
187{
188 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
189
190 if (frh->src_len && (rule4->src_len != frh->src_len))
191 return 0;
192
193 if (frh->dst_len && (rule4->dst_len != frh->dst_len))
194 return 0;
195
196 if (frh->tos && (rule4->tos != frh->tos))
197 return 0;
198
199#ifdef CONFIG_IP_ROUTE_CLASSID
200 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW])))
201 return 0;
202#endif
203
204 if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC])))
205 return 0;
206
207 if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST])))
208 return 0;
209
210 return 1;
211}
212
213static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
214 struct fib_rule_hdr *frh)
215{
216 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
217
218 frh->dst_len = rule4->dst_len;
219 frh->src_len = rule4->src_len;
220 frh->tos = rule4->tos;
221
222 if (rule4->dst_len)
223 NLA_PUT_BE32(skb, FRA_DST, rule4->dst);
224
225 if (rule4->src_len)
226 NLA_PUT_BE32(skb, FRA_SRC, rule4->src);
227
228#ifdef CONFIG_IP_ROUTE_CLASSID
229 if (rule4->tclassid)
230 NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid);
231#endif
232 return 0;
233
234nla_put_failure:
235 return -ENOBUFS;
236}
237
238static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule)
239{
240 return nla_total_size(4) /* dst */
241 + nla_total_size(4) /* src */
242 + nla_total_size(4); /* flow */
243}
244
245static void fib4_rule_flush_cache(struct fib_rules_ops *ops)
246{
247 rt_cache_flush(ops->fro_net, -1);
248}
249
250static const struct fib_rules_ops __net_initdata fib4_rules_ops_template = {
251 .family = AF_INET,
252 .rule_size = sizeof(struct fib4_rule),
253 .addr_size = sizeof(u32),
254 .action = fib4_rule_action,
255 .match = fib4_rule_match,
256 .configure = fib4_rule_configure,
257 .compare = fib4_rule_compare,
258 .fill = fib4_rule_fill,
259 .default_pref = fib_default_rule_pref,
260 .nlmsg_payload = fib4_rule_nlmsg_payload,
261 .flush_cache = fib4_rule_flush_cache,
262 .nlgroup = RTNLGRP_IPV4_RULE,
263 .policy = fib4_rule_policy,
264 .owner = THIS_MODULE,
265};
266
267static int fib_default_rules_init(struct fib_rules_ops *ops)
268{
269 int err;
270
271 err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, 0);
272 if (err < 0)
273 return err;
274 err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0);
275 if (err < 0)
276 return err;
277 err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0);
278 if (err < 0)
279 return err;
280 return 0;
281}
282
283int __net_init fib4_rules_init(struct net *net)
284{
285 int err;
286 struct fib_rules_ops *ops;
287
288 ops = fib_rules_register(&fib4_rules_ops_template, net);
289 if (IS_ERR(ops))
290 return PTR_ERR(ops);
291
292 err = fib_default_rules_init(ops);
293 if (err < 0)
294 goto fail;
295 net->ipv4.rules_ops = ops;
296 return 0;
297
298fail:
299 /* also cleans all rules already added */
300 fib_rules_unregister(ops);
301 return err;
302}
303
304void __net_exit fib4_rules_exit(struct net *net)
305{
306 fib_rules_unregister(net->ipv4.rules_ops);
307}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * IPv4 Forwarding Information Base: policy rules.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 * Thomas Graf <tgraf@suug.ch>
11 *
12 * Fixes:
13 * Rani Assaf : local_rule cannot be deleted
14 * Marc Boucher : routing by fwmark
15 */
16
17#include <linux/types.h>
18#include <linux/kernel.h>
19#include <linux/netdevice.h>
20#include <linux/netlink.h>
21#include <linux/inetdevice.h>
22#include <linux/init.h>
23#include <linux/list.h>
24#include <linux/rcupdate.h>
25#include <linux/export.h>
26#include <net/inet_dscp.h>
27#include <net/ip.h>
28#include <net/route.h>
29#include <net/tcp.h>
30#include <net/ip_fib.h>
31#include <net/nexthop.h>
32#include <net/fib_rules.h>
33#include <linux/indirect_call_wrapper.h>
34
35struct fib4_rule {
36 struct fib_rule common;
37 u8 dst_len;
38 u8 src_len;
39 dscp_t dscp;
40 __be32 src;
41 __be32 srcmask;
42 __be32 dst;
43 __be32 dstmask;
44#ifdef CONFIG_IP_ROUTE_CLASSID
45 u32 tclassid;
46#endif
47};
48
49static bool fib4_rule_matchall(const struct fib_rule *rule)
50{
51 struct fib4_rule *r = container_of(rule, struct fib4_rule, common);
52
53 if (r->dst_len || r->src_len || r->dscp)
54 return false;
55 return fib_rule_matchall(rule);
56}
57
58bool fib4_rule_default(const struct fib_rule *rule)
59{
60 if (!fib4_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL ||
61 rule->l3mdev)
62 return false;
63 if (rule->table != RT_TABLE_LOCAL && rule->table != RT_TABLE_MAIN &&
64 rule->table != RT_TABLE_DEFAULT)
65 return false;
66 return true;
67}
68EXPORT_SYMBOL_GPL(fib4_rule_default);
69
70int fib4_rules_dump(struct net *net, struct notifier_block *nb,
71 struct netlink_ext_ack *extack)
72{
73 return fib_rules_dump(net, nb, AF_INET, extack);
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
108INDIRECT_CALLABLE_SCOPE int fib4_rule_action(struct fib_rule *rule,
109 struct flowi *flp, int flags,
110 struct fib_lookup_arg *arg)
111{
112 int err = -EAGAIN;
113 struct fib_table *tbl;
114 u32 tb_id;
115
116 switch (rule->action) {
117 case FR_ACT_TO_TBL:
118 break;
119
120 case FR_ACT_UNREACHABLE:
121 return -ENETUNREACH;
122
123 case FR_ACT_PROHIBIT:
124 return -EACCES;
125
126 case FR_ACT_BLACKHOLE:
127 default:
128 return -EINVAL;
129 }
130
131 rcu_read_lock();
132
133 tb_id = fib_rule_get_table(rule, arg);
134 tbl = fib_get_table(rule->fr_net, tb_id);
135 if (tbl)
136 err = fib_table_lookup(tbl, &flp->u.ip4,
137 (struct fib_result *)arg->result,
138 arg->flags);
139
140 rcu_read_unlock();
141 return err;
142}
143
144INDIRECT_CALLABLE_SCOPE bool fib4_rule_suppress(struct fib_rule *rule,
145 int flags,
146 struct fib_lookup_arg *arg)
147{
148 struct fib_result *result = arg->result;
149 struct net_device *dev = NULL;
150
151 if (result->fi) {
152 struct fib_nh_common *nhc = fib_info_nhc(result->fi, 0);
153
154 dev = nhc->nhc_dev;
155 }
156
157 /* do not accept result if the route does
158 * not meet the required prefix length
159 */
160 if (result->prefixlen <= rule->suppress_prefixlen)
161 goto suppress_route;
162
163 /* do not accept result if the route uses a device
164 * belonging to a forbidden interface group
165 */
166 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
167 goto suppress_route;
168
169 return false;
170
171suppress_route:
172 if (!(arg->flags & FIB_LOOKUP_NOREF))
173 fib_info_put(result->fi);
174 return true;
175}
176
177INDIRECT_CALLABLE_SCOPE int fib4_rule_match(struct fib_rule *rule,
178 struct flowi *fl, int flags)
179{
180 struct fib4_rule *r = (struct fib4_rule *) rule;
181 struct flowi4 *fl4 = &fl->u.ip4;
182 __be32 daddr = fl4->daddr;
183 __be32 saddr = fl4->saddr;
184
185 if (((saddr ^ r->src) & r->srcmask) ||
186 ((daddr ^ r->dst) & r->dstmask))
187 return 0;
188
189 if (r->dscp && r->dscp != inet_dsfield_to_dscp(fl4->flowi4_tos))
190 return 0;
191
192 if (rule->ip_proto && (rule->ip_proto != fl4->flowi4_proto))
193 return 0;
194
195 if (fib_rule_port_range_set(&rule->sport_range) &&
196 !fib_rule_port_inrange(&rule->sport_range, fl4->fl4_sport))
197 return 0;
198
199 if (fib_rule_port_range_set(&rule->dport_range) &&
200 !fib_rule_port_inrange(&rule->dport_range, fl4->fl4_dport))
201 return 0;
202
203 return 1;
204}
205
206static struct fib_table *fib_empty_table(struct net *net)
207{
208 u32 id = 1;
209
210 while (1) {
211 if (!fib_get_table(net, id))
212 return fib_new_table(net, id);
213
214 if (id++ == RT_TABLE_MAX)
215 break;
216 }
217 return NULL;
218}
219
220static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
221 struct fib_rule_hdr *frh,
222 struct nlattr **tb,
223 struct netlink_ext_ack *extack)
224{
225 struct net *net = sock_net(skb->sk);
226 int err = -EINVAL;
227 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
228
229 if (!inet_validate_dscp(frh->tos)) {
230 NL_SET_ERR_MSG(extack,
231 "Invalid dsfield (tos): ECN bits must be 0");
232 goto errout;
233 }
234 /* IPv4 currently doesn't handle high order DSCP bits correctly */
235 if (frh->tos & ~IPTOS_TOS_MASK) {
236 NL_SET_ERR_MSG(extack, "Invalid tos");
237 goto errout;
238 }
239 rule4->dscp = inet_dsfield_to_dscp(frh->tos);
240
241 /* split local/main if they are not already split */
242 err = fib_unmerge(net);
243 if (err)
244 goto errout;
245
246 if (rule->table == RT_TABLE_UNSPEC && !rule->l3mdev) {
247 if (rule->action == FR_ACT_TO_TBL) {
248 struct fib_table *table;
249
250 table = fib_empty_table(net);
251 if (!table) {
252 err = -ENOBUFS;
253 goto errout;
254 }
255
256 rule->table = table->tb_id;
257 }
258 }
259
260 if (frh->src_len)
261 rule4->src = nla_get_in_addr(tb[FRA_SRC]);
262
263 if (frh->dst_len)
264 rule4->dst = nla_get_in_addr(tb[FRA_DST]);
265
266#ifdef CONFIG_IP_ROUTE_CLASSID
267 if (tb[FRA_FLOW]) {
268 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
269 if (rule4->tclassid)
270 atomic_inc(&net->ipv4.fib_num_tclassid_users);
271 }
272#endif
273
274 if (fib_rule_requires_fldissect(rule))
275 net->ipv4.fib_rules_require_fldissect++;
276
277 rule4->src_len = frh->src_len;
278 rule4->srcmask = inet_make_mask(rule4->src_len);
279 rule4->dst_len = frh->dst_len;
280 rule4->dstmask = inet_make_mask(rule4->dst_len);
281
282 net->ipv4.fib_has_custom_rules = true;
283
284 err = 0;
285errout:
286 return err;
287}
288
289static int fib4_rule_delete(struct fib_rule *rule)
290{
291 struct net *net = rule->fr_net;
292 int err;
293
294 /* split local/main if they are not already split */
295 err = fib_unmerge(net);
296 if (err)
297 goto errout;
298
299#ifdef CONFIG_IP_ROUTE_CLASSID
300 if (((struct fib4_rule *)rule)->tclassid)
301 atomic_dec(&net->ipv4.fib_num_tclassid_users);
302#endif
303 net->ipv4.fib_has_custom_rules = true;
304
305 if (net->ipv4.fib_rules_require_fldissect &&
306 fib_rule_requires_fldissect(rule))
307 net->ipv4.fib_rules_require_fldissect--;
308errout:
309 return err;
310}
311
312static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
313 struct nlattr **tb)
314{
315 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
316
317 if (frh->src_len && (rule4->src_len != frh->src_len))
318 return 0;
319
320 if (frh->dst_len && (rule4->dst_len != frh->dst_len))
321 return 0;
322
323 if (frh->tos && inet_dscp_to_dsfield(rule4->dscp) != frh->tos)
324 return 0;
325
326#ifdef CONFIG_IP_ROUTE_CLASSID
327 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW])))
328 return 0;
329#endif
330
331 if (frh->src_len && (rule4->src != nla_get_in_addr(tb[FRA_SRC])))
332 return 0;
333
334 if (frh->dst_len && (rule4->dst != nla_get_in_addr(tb[FRA_DST])))
335 return 0;
336
337 return 1;
338}
339
340static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
341 struct fib_rule_hdr *frh)
342{
343 struct fib4_rule *rule4 = (struct fib4_rule *) rule;
344
345 frh->dst_len = rule4->dst_len;
346 frh->src_len = rule4->src_len;
347 frh->tos = inet_dscp_to_dsfield(rule4->dscp);
348
349 if ((rule4->dst_len &&
350 nla_put_in_addr(skb, FRA_DST, rule4->dst)) ||
351 (rule4->src_len &&
352 nla_put_in_addr(skb, FRA_SRC, rule4->src)))
353 goto nla_put_failure;
354#ifdef CONFIG_IP_ROUTE_CLASSID
355 if (rule4->tclassid &&
356 nla_put_u32(skb, FRA_FLOW, rule4->tclassid))
357 goto nla_put_failure;
358#endif
359 return 0;
360
361nla_put_failure:
362 return -ENOBUFS;
363}
364
365static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule)
366{
367 return nla_total_size(4) /* dst */
368 + nla_total_size(4) /* src */
369 + nla_total_size(4); /* flow */
370}
371
372static void fib4_rule_flush_cache(struct fib_rules_ops *ops)
373{
374 rt_cache_flush(ops->fro_net);
375}
376
377static const struct fib_rules_ops __net_initconst fib4_rules_ops_template = {
378 .family = AF_INET,
379 .rule_size = sizeof(struct fib4_rule),
380 .addr_size = sizeof(u32),
381 .action = fib4_rule_action,
382 .suppress = fib4_rule_suppress,
383 .match = fib4_rule_match,
384 .configure = fib4_rule_configure,
385 .delete = fib4_rule_delete,
386 .compare = fib4_rule_compare,
387 .fill = fib4_rule_fill,
388 .nlmsg_payload = fib4_rule_nlmsg_payload,
389 .flush_cache = fib4_rule_flush_cache,
390 .nlgroup = RTNLGRP_IPV4_RULE,
391 .owner = THIS_MODULE,
392};
393
394static int fib_default_rules_init(struct fib_rules_ops *ops)
395{
396 int err;
397
398 err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL);
399 if (err < 0)
400 return err;
401 err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN);
402 if (err < 0)
403 return err;
404 err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT);
405 if (err < 0)
406 return err;
407 return 0;
408}
409
410int __net_init fib4_rules_init(struct net *net)
411{
412 int err;
413 struct fib_rules_ops *ops;
414
415 ops = fib_rules_register(&fib4_rules_ops_template, net);
416 if (IS_ERR(ops))
417 return PTR_ERR(ops);
418
419 err = fib_default_rules_init(ops);
420 if (err < 0)
421 goto fail;
422 net->ipv4.rules_ops = ops;
423 net->ipv4.fib_has_custom_rules = false;
424 net->ipv4.fib_rules_require_fldissect = 0;
425 return 0;
426
427fail:
428 /* also cleans all rules already added */
429 fib_rules_unregister(ops);
430 return err;
431}
432
433void __net_exit fib4_rules_exit(struct net *net)
434{
435 fib_rules_unregister(net->ipv4.rules_ops);
436}