summaryrefslogtreecommitdiff
path: root/net/ipv6/fib6_rules.c
blob: 7c20038330104e9c1dd9f93f38667cff9a0fadc0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
// SPDX-License-Identifier: GPL-2.0-only
/*
 * net/ipv6/fib6_rules.c	IPv6 Routing Policy Rules
 *
 * Copyright (C)2003-2006 Helsinki University of Technology
 * Copyright (C)2003-2006 USAGI/WIDE Project
 *
 * Authors
 *	Thomas Graf		<tgraf@suug.ch>
 *	Ville Nuorvala		<vnuorval@tcs.hut.fi>
 */

#include <linux/netdevice.h>
#include <linux/notifier.h>
#include <linux/export.h>
#include <linux/indirect_call_wrapper.h>

#include <net/fib_rules.h>
#include <net/inet_dscp.h>
#include <net/ipv6.h>
#include <net/addrconf.h>
#include <net/ip6_route.h>
#include <net/netlink.h>

struct fib6_rule {
	struct fib_rule		common;
	struct rt6key		src;
	struct rt6key		dst;
	dscp_t			dscp;
};

static bool fib6_rule_matchall(const struct fib_rule *rule)
{
	struct fib6_rule *r = container_of(rule, struct fib6_rule, common);

	if (r->dst.plen || r->src.plen || r->dscp)
		return false;
	return fib_rule_matchall(rule);
}

bool fib6_rule_default(const struct fib_rule *rule)
{
	if (!fib6_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL ||
	    rule->l3mdev)
		return false;
	if (rule->table != RT6_TABLE_LOCAL && rule->table != RT6_TABLE_MAIN)
		return false;
	return true;
}
EXPORT_SYMBOL_GPL(fib6_rule_default);

int fib6_rules_dump(struct net *net, struct notifier_block *nb,
		    struct netlink_ext_ack *extack)
{
	return fib_rules_dump(net, nb, AF_INET6, extack);
}

unsigned int fib6_rules_seq_read(struct net *net)
{
	return fib_rules_seq_read(net, AF_INET6);
}

/* called with rcu lock held; no reference taken on fib6_info */
int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
		struct fib6_result *res, int flags)
{
	int err;

	if (net->ipv6.fib6_has_custom_rules) {
		struct fib_lookup_arg arg = {
			.lookup_ptr = fib6_table_lookup,
			.lookup_data = &oif,
			.result = res,
			.flags = FIB_LOOKUP_NOREF,
		};

		l3mdev_update_flow(net, flowi6_to_flowi(fl6));

		err = fib_rules_lookup(net->ipv6.fib6_rules_ops,
				       flowi6_to_flowi(fl6), flags, &arg);
	} else {
		err = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, oif,
					fl6, res, flags);
		if (err || res->f6i == net->ipv6.fib6_null_entry)
			err = fib6_table_lookup(net, net->ipv6.fib6_main_tbl,
						oif, fl6, res, flags);
	}

	return err;
}

struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
				   const struct sk_buff *skb,
				   int flags, pol_lookup_t lookup)
{
	if (net->ipv6.fib6_has_custom_rules) {
		struct fib6_result res = {};
		struct fib_lookup_arg arg = {
			.lookup_ptr = lookup,
			.lookup_data = skb,
			.result = &res,
			.flags = FIB_LOOKUP_NOREF,
		};

		/* update flow if oif or iif point to device enslaved to l3mdev */
		l3mdev_update_flow(net, flowi6_to_flowi(fl6));

		fib_rules_lookup(net->ipv6.fib6_rules_ops,
				 flowi6_to_flowi(fl6), flags, &arg);

		if (res.rt6)
			return &res.rt6->dst;
	} else {
		struct rt6_info *rt;

		rt = pol_lookup_func(lookup,
			     net, net->ipv6.fib6_local_tbl, fl6, skb, flags);
		if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN)
			return &rt->dst;
		ip6_rt_put_flags(rt, flags);
		rt = pol_lookup_func(lookup,
			     net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
		if (rt->dst.error != -EAGAIN)
			return &rt->dst;
		ip6_rt_put_flags(rt, flags);
	}

	if (!(flags & RT6_LOOKUP_F_DST_NOREF))
		dst_hold(&net->ipv6.ip6_null_entry->dst);
	return &net->ipv6.ip6_null_entry->dst;
}

static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags,
			   struct flowi6 *flp6, const struct net_device *dev)
{
	struct fib6_rule *r = (struct fib6_rule *)rule;

	/* If we need to find a source address for this traffic,
	 * we check the result if it meets requirement of the rule.
	 */
	if ((rule->flags & FIB_RULE_FIND_SADDR) &&
	    r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
		struct in6_addr saddr;

		if (ipv6_dev_get_saddr(net, dev, &flp6->daddr,
				       rt6_flags2srcprefs(flags), &saddr))
			return -EAGAIN;

		if (!ipv6_prefix_equal(&saddr, &r->src.addr, r->src.plen))
			return -EAGAIN;

		flp6->saddr = saddr;
	}

	return 0;
}

static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp,
				int flags, struct fib_lookup_arg *arg)
{
	struct fib6_result *res = arg->result;
	struct flowi6 *flp6 = &flp->u.ip6;
	struct net *net = rule->fr_net;
	struct fib6_table *table;
	int err, *oif;
	u32 tb_id;

	switch (rule->action) {
	case FR_ACT_TO_TBL:
		break;
	case FR_ACT_UNREACHABLE:
		return -ENETUNREACH;
	case FR_ACT_PROHIBIT:
		return -EACCES;
	case FR_ACT_BLACKHOLE:
	default:
		return -EINVAL;
	}

	tb_id = fib_rule_get_table(rule, arg);
	table = fib6_get_table(net, tb_id);
	if (!table)
		return -EAGAIN;

	oif = (int *)arg->lookup_data;
	err = fib6_table_lookup(net, table, *oif, flp6, res, flags);
	if (!err && res->f6i != net->ipv6.fib6_null_entry)
		err = fib6_rule_saddr(net, rule, flags, flp6,
				      res->nh->fib_nh_dev);
	else
		err = -EAGAIN;

	return err;
}

static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
			      int flags, struct fib_lookup_arg *arg)
{
	struct fib6_result *res = arg->result;
	struct flowi6 *flp6 = &flp->u.ip6;
	struct rt6_info *rt = NULL;
	struct fib6_table *table;
	struct net *net = rule->fr_net;
	pol_lookup_t lookup = arg->lookup_ptr;
	int err = 0;
	u32 tb_id;

	switch (rule->action) {
	case FR_ACT_TO_TBL:
		break;
	case FR_ACT_UNREACHABLE:
		err = -ENETUNREACH;
		rt = net->ipv6.ip6_null_entry;
		goto discard_pkt;
	default:
	case FR_ACT_BLACKHOLE:
		err = -EINVAL;
		rt = net->ipv6.ip6_blk_hole_entry;
		goto discard_pkt;
	case FR_ACT_PROHIBIT:
		err = -EACCES;
		rt = net->ipv6.ip6_prohibit_entry;
		goto discard_pkt;
	}

	tb_id = fib_rule_get_table(rule, arg);
	table = fib6_get_table(net, tb_id);
	if (!table) {
		err = -EAGAIN;
		goto out;
	}

	rt = pol_lookup_func(lookup,
			     net, table, flp6, arg->lookup_data, flags);
	if (rt != net->ipv6.ip6_null_entry) {
		err = fib6_rule_saddr(net, rule, flags, flp6,
				      ip6_dst_idev(&rt->dst)->dev);

		if (err == -EAGAIN)
			goto again;

		err = rt->dst.error;
		if (err != -EAGAIN)
			goto out;
	}
again:
	ip6_rt_put_flags(rt, flags);
	err = -EAGAIN;
	rt = NULL;
	goto out;

discard_pkt:
	if (!(flags & RT6_LOOKUP_F_DST_NOREF))
		dst_hold(&rt->dst);
out:
	res->rt6 = rt;
	return err;
}

INDIRECT_CALLABLE_SCOPE int fib6_rule_action(struct fib_rule *rule,
					     struct flowi *flp, int flags,
					     struct fib_lookup_arg *arg)
{
	if (arg->lookup_ptr == fib6_table_lookup)
		return fib6_rule_action_alt(rule, flp, flags, arg);

	return __fib6_rule_action(rule, flp, flags, arg);
}

INDIRECT_CALLABLE_SCOPE bool fib6_rule_suppress(struct fib_rule *rule,
						int flags,
						struct fib_lookup_arg *arg)
{
	struct fib6_result *res = arg->result;
	struct rt6_info *rt = res->rt6;
	struct net_device *dev = NULL;

	if (!rt)
		return false;

	if (rt->rt6i_idev)
		dev = rt->rt6i_idev->dev;

	/* do not accept result if the route does
	 * not meet the required prefix length
	 */
	if (rt->rt6i_dst.plen <= rule->suppress_prefixlen)
		goto suppress_route;

	/* do not accept result if the route uses a device
	 * belonging to a forbidden interface group
	 */
	if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
		goto suppress_route;

	return false;

suppress_route:
	ip6_rt_put_flags(rt, flags);
	return true;
}

INDIRECT_CALLABLE_SCOPE int fib6_rule_match(struct fib_rule *rule,
					    struct flowi *fl, int flags)
{
	struct fib6_rule *r = (struct fib6_rule *) rule;
	struct flowi6 *fl6 = &fl->u.ip6;

	if (r->dst.plen &&
	    !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen))
		return 0;

	/*
	 * If FIB_RULE_FIND_SADDR is set and we do not have a
	 * source address for the traffic, we defer check for
	 * source address.
	 */
	if (r->src.plen) {
		if (flags & RT6_LOOKUP_F_HAS_SADDR) {
			if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr,
					       r->src.plen))
				return 0;
		} else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
			return 0;
	}

	if (r->dscp && r->dscp != ip6_dscp(fl6->flowlabel))
		return 0;

	if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto))
		return 0;

	if (fib_rule_port_range_set(&rule->sport_range) &&
	    !fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport))
		return 0;

	if (fib_rule_port_range_set(&rule->dport_range) &&
	    !fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport))
		return 0;

	return 1;
}

static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
			       struct fib_rule_hdr *frh,
			       struct nlattr **tb,
			       struct netlink_ext_ack *extack)
{
	int err = -EINVAL;
	struct net *net = sock_net(skb->sk);
	struct fib6_rule *rule6 = (struct fib6_rule *) rule;

	if (!inet_validate_dscp(frh->tos)) {
		NL_SET_ERR_MSG(extack,
			       "Invalid dsfield (tos): ECN bits must be 0");
		goto errout;
	}
	rule6->dscp = inet_dsfield_to_dscp(frh->tos);

	if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) {
		if (rule->table == RT6_TABLE_UNSPEC) {
			NL_SET_ERR_MSG(extack, "Invalid table");
			goto errout;
		}

		if (fib6_new_table(net, rule->table) == NULL) {
			err = -ENOBUFS;
			goto errout;
		}
	}

	if (frh->src_len)
		rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]);

	if (frh->dst_len)
		rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]);

	rule6->src.plen = frh->src_len;
	rule6->dst.plen = frh->dst_len;

	if (fib_rule_requires_fldissect(rule))
		net->ipv6.fib6_rules_require_fldissect++;

	net->ipv6.fib6_has_custom_rules = true;
	err = 0;
errout:
	return err;
}

static int fib6_rule_delete(struct fib_rule *rule)
{
	struct net *net = rule->fr_net;

	if (net->ipv6.fib6_rules_require_fldissect &&
	    fib_rule_requires_fldissect(rule))
		net->ipv6.fib6_rules_require_fldissect--;

	return 0;
}

static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
			     struct nlattr **tb)
{
	struct fib6_rule *rule6 = (struct fib6_rule *) rule;

	if (frh->src_len && (rule6->src.plen != frh->src_len))
		return 0;

	if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
		return 0;

	if (frh->tos && inet_dscp_to_dsfield(rule6->dscp) != frh->tos)
		return 0;

	if (frh->src_len &&
	    nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
		return 0;

	if (frh->dst_len &&
	    nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
		return 0;

	return 1;
}

static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
			  struct fib_rule_hdr *frh)
{
	struct fib6_rule *rule6 = (struct fib6_rule *) rule;

	frh->dst_len = rule6->dst.plen;
	frh->src_len = rule6->src.plen;
	frh->tos = inet_dscp_to_dsfield(rule6->dscp);

	if ((rule6->dst.plen &&
	     nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) ||
	    (rule6->src.plen &&
	     nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr)))
		goto nla_put_failure;
	return 0;

nla_put_failure:
	return -ENOBUFS;
}

static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
{
	return nla_total_size(16) /* dst */
	       + nla_total_size(16); /* src */
}

static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = {
	.family			= AF_INET6,
	.rule_size		= sizeof(struct fib6_rule),
	.addr_size		= sizeof(struct in6_addr),
	.action			= fib6_rule_action,
	.match			= fib6_rule_match,
	.suppress		= fib6_rule_suppress,
	.configure		= fib6_rule_configure,
	.delete			= fib6_rule_delete,
	.compare		= fib6_rule_compare,
	.fill			= fib6_rule_fill,
	.nlmsg_payload		= fib6_rule_nlmsg_payload,
	.nlgroup		= RTNLGRP_IPV6_RULE,
	.owner			= THIS_MODULE,
	.fro_net		= &init_net,
};

static int __net_init fib6_rules_net_init(struct net *net)
{
	struct fib_rules_ops *ops;
	int err;

	ops = fib_rules_register(&fib6_rules_ops_template, net);
	if (IS_ERR(ops))
		return PTR_ERR(ops);

	err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0);
	if (err)
		goto out_fib6_rules_ops;

	err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0);
	if (err)
		goto out_fib6_rules_ops;

	net->ipv6.fib6_rules_ops = ops;
	net->ipv6.fib6_rules_require_fldissect = 0;
out:
	return err;

out_fib6_rules_ops:
	fib_rules_unregister(ops);
	goto out;
}

static void __net_exit fib6_rules_net_exit_batch(struct list_head *net_list)
{
	struct net *net;

	rtnl_lock();
	list_for_each_entry(net, net_list, exit_list) {
		fib_rules_unregister(net->ipv6.fib6_rules_ops);
		cond_resched();
	}
	rtnl_unlock();
}

static struct pernet_operations fib6_rules_net_ops = {
	.init = fib6_rules_net_init,
	.exit_batch = fib6_rules_net_exit_batch,
};

int __init fib6_rules_init(void)
{
	return register_pernet_subsys(&fib6_rules_net_ops);
}


void fib6_rules_cleanup(void)
{
	unregister_pernet_subsys(&fib6_rules_net_ops);
}