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 | static 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 | |
59 | bool 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 | } |
69 | EXPORT_SYMBOL_GPL(fib4_rule_default); |
70 | |
71 | int fib4_rules_dump(struct net *net, struct notifier_block *nb) |
72 | { |
73 | return fib_rules_dump(net, nb, AF_INET); |
74 | } |
75 | |
76 | unsigned int fib4_rules_seq_read(struct net *net) |
77 | { |
78 | return fib_rules_seq_read(net, AF_INET); |
79 | } |
80 | |
81 | int __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 | } |
106 | EXPORT_SYMBOL_GPL(__fib_lookup); |
107 | |
108 | static 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 | |
143 | static 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 | |
165 | suppress_route: |
166 | if (!(arg->flags & FIB_LOOKUP_NOREF)) |
167 | fib_info_put(result->fi); |
168 | return true; |
169 | } |
170 | |
171 | static 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 | |
199 | static struct fib_table *fib_empty_table(struct net *net) |
200 | { |
201 | u32 id = 1; |
202 | |
203 | while (1) { |
204 | if (!fib_get_table(net, id)) |
205 | return fib_new_table(net, id); |
206 | |
207 | if (id++ == RT_TABLE_MAX) |
208 | break; |
209 | } |
210 | return NULL; |
211 | } |
212 | |
213 | static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = { |
214 | FRA_GENERIC_POLICY, |
215 | [FRA_FLOW] = { .type = NLA_U32 }, |
216 | }; |
217 | |
218 | static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb, |
219 | struct fib_rule_hdr *frh, |
220 | struct nlattr **tb, |
221 | struct netlink_ext_ack *extack) |
222 | { |
223 | struct net *net = sock_net(skb->sk); |
224 | int err = -EINVAL; |
225 | struct fib4_rule *rule4 = (struct fib4_rule *) rule; |
226 | |
227 | if (frh->tos & ~IPTOS_TOS_MASK) { |
228 | NL_SET_ERR_MSG(extack, "Invalid tos" ); |
229 | goto errout; |
230 | } |
231 | |
232 | /* split local/main if they are not already split */ |
233 | err = fib_unmerge(net); |
234 | if (err) |
235 | goto errout; |
236 | |
237 | if (rule->table == RT_TABLE_UNSPEC && !rule->l3mdev) { |
238 | if (rule->action == FR_ACT_TO_TBL) { |
239 | struct fib_table *table; |
240 | |
241 | table = fib_empty_table(net); |
242 | if (!table) { |
243 | err = -ENOBUFS; |
244 | goto errout; |
245 | } |
246 | |
247 | rule->table = table->tb_id; |
248 | } |
249 | } |
250 | |
251 | if (frh->src_len) |
252 | rule4->src = nla_get_in_addr(tb[FRA_SRC]); |
253 | |
254 | if (frh->dst_len) |
255 | rule4->dst = nla_get_in_addr(tb[FRA_DST]); |
256 | |
257 | #ifdef CONFIG_IP_ROUTE_CLASSID |
258 | if (tb[FRA_FLOW]) { |
259 | rule4->tclassid = nla_get_u32(tb[FRA_FLOW]); |
260 | if (rule4->tclassid) |
261 | net->ipv4.fib_num_tclassid_users++; |
262 | } |
263 | #endif |
264 | |
265 | if (fib_rule_requires_fldissect(rule)) |
266 | net->ipv4.fib_rules_require_fldissect++; |
267 | |
268 | rule4->src_len = frh->src_len; |
269 | rule4->srcmask = inet_make_mask(rule4->src_len); |
270 | rule4->dst_len = frh->dst_len; |
271 | rule4->dstmask = inet_make_mask(rule4->dst_len); |
272 | rule4->tos = frh->tos; |
273 | |
274 | net->ipv4.fib_has_custom_rules = true; |
275 | |
276 | err = 0; |
277 | errout: |
278 | return err; |
279 | } |
280 | |
281 | static int fib4_rule_delete(struct fib_rule *rule) |
282 | { |
283 | struct net *net = rule->fr_net; |
284 | int err; |
285 | |
286 | /* split local/main if they are not already split */ |
287 | err = fib_unmerge(net); |
288 | if (err) |
289 | goto errout; |
290 | |
291 | #ifdef CONFIG_IP_ROUTE_CLASSID |
292 | if (((struct fib4_rule *)rule)->tclassid) |
293 | net->ipv4.fib_num_tclassid_users--; |
294 | #endif |
295 | net->ipv4.fib_has_custom_rules = true; |
296 | |
297 | if (net->ipv4.fib_rules_require_fldissect && |
298 | fib_rule_requires_fldissect(rule)) |
299 | net->ipv4.fib_rules_require_fldissect--; |
300 | errout: |
301 | return err; |
302 | } |
303 | |
304 | static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, |
305 | struct nlattr **tb) |
306 | { |
307 | struct fib4_rule *rule4 = (struct fib4_rule *) rule; |
308 | |
309 | if (frh->src_len && (rule4->src_len != frh->src_len)) |
310 | return 0; |
311 | |
312 | if (frh->dst_len && (rule4->dst_len != frh->dst_len)) |
313 | return 0; |
314 | |
315 | if (frh->tos && (rule4->tos != frh->tos)) |
316 | return 0; |
317 | |
318 | #ifdef CONFIG_IP_ROUTE_CLASSID |
319 | if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW]))) |
320 | return 0; |
321 | #endif |
322 | |
323 | if (frh->src_len && (rule4->src != nla_get_in_addr(tb[FRA_SRC]))) |
324 | return 0; |
325 | |
326 | if (frh->dst_len && (rule4->dst != nla_get_in_addr(tb[FRA_DST]))) |
327 | return 0; |
328 | |
329 | return 1; |
330 | } |
331 | |
332 | static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb, |
333 | struct fib_rule_hdr *frh) |
334 | { |
335 | struct fib4_rule *rule4 = (struct fib4_rule *) rule; |
336 | |
337 | frh->dst_len = rule4->dst_len; |
338 | frh->src_len = rule4->src_len; |
339 | frh->tos = rule4->tos; |
340 | |
341 | if ((rule4->dst_len && |
342 | nla_put_in_addr(skb, FRA_DST, rule4->dst)) || |
343 | (rule4->src_len && |
344 | nla_put_in_addr(skb, FRA_SRC, rule4->src))) |
345 | goto nla_put_failure; |
346 | #ifdef CONFIG_IP_ROUTE_CLASSID |
347 | if (rule4->tclassid && |
348 | nla_put_u32(skb, FRA_FLOW, rule4->tclassid)) |
349 | goto nla_put_failure; |
350 | #endif |
351 | return 0; |
352 | |
353 | nla_put_failure: |
354 | return -ENOBUFS; |
355 | } |
356 | |
357 | static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule) |
358 | { |
359 | return nla_total_size(4) /* dst */ |
360 | + nla_total_size(4) /* src */ |
361 | + nla_total_size(4); /* flow */ |
362 | } |
363 | |
364 | static void fib4_rule_flush_cache(struct fib_rules_ops *ops) |
365 | { |
366 | rt_cache_flush(ops->fro_net); |
367 | } |
368 | |
369 | static const struct fib_rules_ops __net_initconst fib4_rules_ops_template = { |
370 | .family = AF_INET, |
371 | .rule_size = sizeof(struct fib4_rule), |
372 | .addr_size = sizeof(u32), |
373 | .action = fib4_rule_action, |
374 | .suppress = fib4_rule_suppress, |
375 | .match = fib4_rule_match, |
376 | .configure = fib4_rule_configure, |
377 | .delete = fib4_rule_delete, |
378 | .compare = fib4_rule_compare, |
379 | .fill = fib4_rule_fill, |
380 | .nlmsg_payload = fib4_rule_nlmsg_payload, |
381 | .flush_cache = fib4_rule_flush_cache, |
382 | .nlgroup = RTNLGRP_IPV4_RULE, |
383 | .policy = fib4_rule_policy, |
384 | .owner = THIS_MODULE, |
385 | }; |
386 | |
387 | static int fib_default_rules_init(struct fib_rules_ops *ops) |
388 | { |
389 | int err; |
390 | |
391 | err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, 0); |
392 | if (err < 0) |
393 | return err; |
394 | err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0); |
395 | if (err < 0) |
396 | return err; |
397 | err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0); |
398 | if (err < 0) |
399 | return err; |
400 | return 0; |
401 | } |
402 | |
403 | int __net_init fib4_rules_init(struct net *net) |
404 | { |
405 | int err; |
406 | struct fib_rules_ops *ops; |
407 | |
408 | ops = fib_rules_register(&fib4_rules_ops_template, net); |
409 | if (IS_ERR(ops)) |
410 | return PTR_ERR(ops); |
411 | |
412 | err = fib_default_rules_init(ops); |
413 | if (err < 0) |
414 | goto fail; |
415 | net->ipv4.rules_ops = ops; |
416 | net->ipv4.fib_has_custom_rules = false; |
417 | net->ipv4.fib_rules_require_fldissect = 0; |
418 | return 0; |
419 | |
420 | fail: |
421 | /* also cleans all rules already added */ |
422 | fib_rules_unregister(ops); |
423 | return err; |
424 | } |
425 | |
426 | void __net_exit fib4_rules_exit(struct net *net) |
427 | { |
428 | fib_rules_unregister(net->ipv4.rules_ops); |
429 | } |
430 | |