addrlabel.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * IPv6 Address Label subsystem
  4 * for the IPv6 "Default" Source Address Selection
  5 *
  6 * Copyright (C)2007 USAGI/WIDE Project
  7 */
  8/*
  9 * Author:
 10 *	YOSHIFUJI Hideaki @ USAGI/WIDE Project <yoshfuji@linux-ipv6.org>
 11 */
 12
 13#include <linux/kernel.h>
 14#include <linux/list.h>
 15#include <linux/rcupdate.h>
 16#include <linux/in6.h>
 17#include <linux/slab.h>
 18#include <net/addrconf.h>
 19#include <linux/if_addrlabel.h>
 20#include <linux/netlink.h>
 21#include <linux/rtnetlink.h>
 22
 23/*
 24 * Policy Table
 25 */
 26struct ip6addrlbl_entry {
 27	struct in6_addr prefix;
 28	int prefixlen;
 29	int ifindex;
 30	int addrtype;
 31	u32 label;
 32	struct hlist_node list;
 33	struct rcu_head rcu;
 34};
 35
 36/*
 37 * Default policy table (RFC6724 + extensions)
 38 *
 39 * prefix		addr_type	label
 40 * -------------------------------------------------------------------------
 41 * ::1/128		LOOPBACK	0
 42 * ::/0			N/A		1
 43 * 2002::/16		N/A		2
 44 * ::/96		COMPATv4	3
 45 * ::ffff:0:0/96	V4MAPPED	4
 46 * fc00::/7		N/A		5		ULA (RFC 4193)
 47 * 2001::/32		N/A		6		Teredo (RFC 4380)
 48 * 2001:10::/28		N/A		7		ORCHID (RFC 4843)
 49 * fec0::/10		N/A		11		Site-local
 50 *							(deprecated by RFC3879)
 51 * 3ffe::/16		N/A		12		6bone
 52 *
 53 * Note: 0xffffffff is used if we do not have any policies.
 54 * Note: Labels for ULA and 6to4 are different from labels listed in RFC6724.
 55 */
 56
 57#define IPV6_ADDR_LABEL_DEFAULT	0xffffffffUL
 58
 59static const __net_initconst struct ip6addrlbl_init_table
 60{
 61	const struct in6_addr *prefix;
 62	int prefixlen;
 63	u32 label;
 64} ip6addrlbl_init_table[] = {
 65	{	/* ::/0 */
 66		.prefix = &in6addr_any,
 67		.label = 1,
 68	}, {	/* fc00::/7 */
 69		.prefix = &(struct in6_addr){ { { 0xfc } } } ,
 70		.prefixlen = 7,
 71		.label = 5,
 72	}, {	/* fec0::/10 */
 73		.prefix = &(struct in6_addr){ { { 0xfe, 0xc0 } } },
 74		.prefixlen = 10,
 75		.label = 11,
 76	}, {	/* 2002::/16 */
 77		.prefix = &(struct in6_addr){ { { 0x20, 0x02 } } },
 78		.prefixlen = 16,
 79		.label = 2,
 80	}, {	/* 3ffe::/16 */
 81		.prefix = &(struct in6_addr){ { { 0x3f, 0xfe } } },
 82		.prefixlen = 16,
 83		.label = 12,
 84	}, {	/* 2001::/32 */
 85		.prefix = &(struct in6_addr){ { { 0x20, 0x01 } } },
 86		.prefixlen = 32,
 87		.label = 6,
 88	}, {	/* 2001:10::/28 */
 89		.prefix = &(struct in6_addr){ { { 0x20, 0x01, 0x00, 0x10 } } },
 90		.prefixlen = 28,
 91		.label = 7,
 92	}, {	/* ::ffff:0:0 */
 93		.prefix = &(struct in6_addr){ { { [10] = 0xff, [11] = 0xff } } },
 94		.prefixlen = 96,
 95		.label = 4,
 96	}, {	/* ::/96 */
 97		.prefix = &in6addr_any,
 98		.prefixlen = 96,
 99		.label = 3,
100	}, {	/* ::1/128 */
101		.prefix = &in6addr_loopback,
102		.prefixlen = 128,
103		.label = 0,
104	}
105};
106
107/* Find label */
108static bool __ip6addrlbl_match(const struct ip6addrlbl_entry *p,
109			       const struct in6_addr *addr,
110			       int addrtype, int ifindex)
111{
112	if (p->ifindex && p->ifindex != ifindex)
113		return false;
114	if (p->addrtype && p->addrtype != addrtype)
115		return false;
116	if (!ipv6_prefix_equal(addr, &p->prefix, p->prefixlen))
117		return false;
118	return true;
119}
120
121static struct ip6addrlbl_entry *__ipv6_addr_label(struct net *net,
122						  const struct in6_addr *addr,
123						  int type, int ifindex)
124{
125	struct ip6addrlbl_entry *p;
126
127	hlist_for_each_entry_rcu(p, &net->ipv6.ip6addrlbl_table.head, list) {
128		if (__ip6addrlbl_match(p, addr, type, ifindex))
129			return p;
130	}
131	return NULL;
132}
133
134u32 ipv6_addr_label(struct net *net,
135		    const struct in6_addr *addr, int type, int ifindex)
136{
137	u32 label;
138	struct ip6addrlbl_entry *p;
139
140	type &= IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK;
141
142	rcu_read_lock();
143	p = __ipv6_addr_label(net, addr, type, ifindex);
144	label = p ? p->label : IPV6_ADDR_LABEL_DEFAULT;
145	rcu_read_unlock();
146
147	net_dbg_ratelimited("%s(addr=%pI6, type=%d, ifindex=%d) => %08x\n", __func__, addr, type,
148			    ifindex, label);
149
150	return label;
151}
152
153/* allocate one entry */
154static struct ip6addrlbl_entry *ip6addrlbl_alloc(const struct in6_addr *prefix,
155						 int prefixlen, int ifindex,
156						 u32 label)
157{
158	struct ip6addrlbl_entry *newp;
159	int addrtype;
160
161	net_dbg_ratelimited("%s(prefix=%pI6, prefixlen=%d, ifindex=%d, label=%u)\n", __func__,
162			    prefix, prefixlen, ifindex, (unsigned int)label);
163
164	addrtype = ipv6_addr_type(prefix) & (IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK);
165
166	switch (addrtype) {
167	case IPV6_ADDR_MAPPED:
168		if (prefixlen > 96)
169			return ERR_PTR(-EINVAL);
170		if (prefixlen < 96)
171			addrtype = 0;
172		break;
173	case IPV6_ADDR_COMPATv4:
174		if (prefixlen != 96)
175			addrtype = 0;
176		break;
177	case IPV6_ADDR_LOOPBACK:
178		if (prefixlen != 128)
179			addrtype = 0;
180		break;
181	}
182
183	newp = kmalloc(sizeof(*newp), GFP_KERNEL);
184	if (!newp)
185		return ERR_PTR(-ENOMEM);
186
187	ipv6_addr_prefix(&newp->prefix, prefix, prefixlen);
188	newp->prefixlen = prefixlen;
189	newp->ifindex = ifindex;
190	newp->addrtype = addrtype;
191	newp->label = label;
192	INIT_HLIST_NODE(&newp->list);
193	return newp;
194}
195
196/* add a label */
197static int __ip6addrlbl_add(struct net *net, struct ip6addrlbl_entry *newp,
198			    int replace)
199{
200	struct ip6addrlbl_entry *last = NULL, *p = NULL;
201	struct hlist_node *n;
202	int ret = 0;
203
204	net_dbg_ratelimited("%s(newp=%p, replace=%d)\n", __func__, newp, replace);
205
206	hlist_for_each_entry_safe(p, n,	&net->ipv6.ip6addrlbl_table.head, list) {
207		if (p->prefixlen == newp->prefixlen &&
208		    p->ifindex == newp->ifindex &&
209		    ipv6_addr_equal(&p->prefix, &newp->prefix)) {
210			if (!replace) {
211				ret = -EEXIST;
212				goto out;
213			}
214			hlist_replace_rcu(&p->list, &newp->list);
215			kfree_rcu(p, rcu);
216			goto out;
217		} else if ((p->prefixlen == newp->prefixlen && !p->ifindex) ||
218			   (p->prefixlen < newp->prefixlen)) {
219			hlist_add_before_rcu(&newp->list, &p->list);
220			goto out;
221		}
222		last = p;
223	}
224	if (last)
225		hlist_add_behind_rcu(&newp->list, &last->list);
226	else
227		hlist_add_head_rcu(&newp->list, &net->ipv6.ip6addrlbl_table.head);
228out:
229	if (!ret)
230		WRITE_ONCE(net->ipv6.ip6addrlbl_table.seq,
231			   net->ipv6.ip6addrlbl_table.seq + 1);
232	return ret;
233}
234
235/* add a label */
236static int ip6addrlbl_add(struct net *net,
237			  const struct in6_addr *prefix, int prefixlen,
238			  int ifindex, u32 label, int replace)
239{
240	struct ip6addrlbl_entry *newp;
241	int ret = 0;
242
243	net_dbg_ratelimited("%s(prefix=%pI6, prefixlen=%d, ifindex=%d, label=%u, replace=%d)\n",
244			    __func__, prefix, prefixlen, ifindex, (unsigned int)label, replace);
245
246	newp = ip6addrlbl_alloc(prefix, prefixlen, ifindex, label);
247	if (IS_ERR(newp))
248		return PTR_ERR(newp);
249	spin_lock(&net->ipv6.ip6addrlbl_table.lock);
250	ret = __ip6addrlbl_add(net, newp, replace);
251	spin_unlock(&net->ipv6.ip6addrlbl_table.lock);
252	if (ret)
253		kfree(newp);
254	return ret;
255}
256
257/* remove a label */
258static int __ip6addrlbl_del(struct net *net,
259			    const struct in6_addr *prefix, int prefixlen,
260			    int ifindex)
261{
262	struct ip6addrlbl_entry *p = NULL;
263	struct hlist_node *n;
264	int ret = -ESRCH;
265
266	net_dbg_ratelimited("%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n", __func__, prefix,
267			    prefixlen, ifindex);
268
269	hlist_for_each_entry_safe(p, n, &net->ipv6.ip6addrlbl_table.head, list) {
270		if (p->prefixlen == prefixlen &&
271		    p->ifindex == ifindex &&
272		    ipv6_addr_equal(&p->prefix, prefix)) {
273			hlist_del_rcu(&p->list);
274			kfree_rcu(p, rcu);
275			ret = 0;
276			break;
277		}
278	}
279	return ret;
280}
281
282static int ip6addrlbl_del(struct net *net,
283			  const struct in6_addr *prefix, int prefixlen,
284			  int ifindex)
285{
286	struct in6_addr prefix_buf;
287	int ret;
288
289	net_dbg_ratelimited("%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n", __func__, prefix,
290			    prefixlen, ifindex);
291
292	ipv6_addr_prefix(&prefix_buf, prefix, prefixlen);
293	spin_lock(&net->ipv6.ip6addrlbl_table.lock);
294	ret = __ip6addrlbl_del(net, &prefix_buf, prefixlen, ifindex);
295	spin_unlock(&net->ipv6.ip6addrlbl_table.lock);
296	return ret;
297}
298
299/* add default label */
300static int __net_init ip6addrlbl_net_init(struct net *net)
301{
302	struct ip6addrlbl_entry *p = NULL;
303	struct hlist_node *n;
304	int err;
305	int i;
306
307	spin_lock_init(&net->ipv6.ip6addrlbl_table.lock);
308	INIT_HLIST_HEAD(&net->ipv6.ip6addrlbl_table.head);
309
310	for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) {
311		err = ip6addrlbl_add(net,
312				     ip6addrlbl_init_table[i].prefix,
313				     ip6addrlbl_init_table[i].prefixlen,
314				     0,
315				     ip6addrlbl_init_table[i].label, 0);
316		if (err)
317			goto err_ip6addrlbl_add;
318	}
319	return 0;
320
321err_ip6addrlbl_add:
322	hlist_for_each_entry_safe(p, n, &net->ipv6.ip6addrlbl_table.head, list) {
323		hlist_del_rcu(&p->list);
324		kfree_rcu(p, rcu);
325	}
326	return err;
327}
328
329static void __net_exit ip6addrlbl_net_exit(struct net *net)
330{
331	struct ip6addrlbl_entry *p = NULL;
332	struct hlist_node *n;
333
334	/* Remove all labels belonging to the exiting net */
335	spin_lock(&net->ipv6.ip6addrlbl_table.lock);
336	hlist_for_each_entry_safe(p, n, &net->ipv6.ip6addrlbl_table.head, list) {
337		hlist_del_rcu(&p->list);
338		kfree_rcu(p, rcu);
339	}
340	spin_unlock(&net->ipv6.ip6addrlbl_table.lock);
341}
342
343static struct pernet_operations ipv6_addr_label_ops = {
344	.init = ip6addrlbl_net_init,
345	.exit = ip6addrlbl_net_exit,
346};
347
348int __init ipv6_addr_label_init(void)
349{
350	return register_pernet_subsys(&ipv6_addr_label_ops);
351}
352
353void ipv6_addr_label_cleanup(void)
354{
355	unregister_pernet_subsys(&ipv6_addr_label_ops);
356}
357
358static const struct nla_policy ifal_policy[IFAL_MAX+1] = {
359	[IFAL_ADDRESS]		= { .len = sizeof(struct in6_addr), },
360	[IFAL_LABEL]		= { .len = sizeof(u32), },
361};
362
363static bool addrlbl_ifindex_exists(struct net *net, int ifindex)
364{
365
366	struct net_device *dev;
367
368	rcu_read_lock();
369	dev = dev_get_by_index_rcu(net, ifindex);
370	rcu_read_unlock();
371
372	return dev != NULL;
373}
374
375static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh,
376			     struct netlink_ext_ack *extack)
377{
378	struct net *net = sock_net(skb->sk);
379	struct ifaddrlblmsg *ifal;
380	struct nlattr *tb[IFAL_MAX+1];
381	struct in6_addr *pfx;
382	u32 label;
383	int err = 0;
384
385	err = nlmsg_parse_deprecated(nlh, sizeof(*ifal), tb, IFAL_MAX,
386				     ifal_policy, extack);
387	if (err < 0)
388		return err;
389
390	ifal = nlmsg_data(nlh);
391
392	if (ifal->ifal_family != AF_INET6 ||
393	    ifal->ifal_prefixlen > 128)
394		return -EINVAL;
395
396	if (!tb[IFAL_ADDRESS])
397		return -EINVAL;
398	pfx = nla_data(tb[IFAL_ADDRESS]);
399
400	if (!tb[IFAL_LABEL])
401		return -EINVAL;
402	label = nla_get_u32(tb[IFAL_LABEL]);
403	if (label == IPV6_ADDR_LABEL_DEFAULT)
404		return -EINVAL;
405
406	switch (nlh->nlmsg_type) {
407	case RTM_NEWADDRLABEL:
408		if (ifal->ifal_index &&
409		    !addrlbl_ifindex_exists(net, ifal->ifal_index))
410			return -EINVAL;
411
412		err = ip6addrlbl_add(net, pfx, ifal->ifal_prefixlen,
413				     ifal->ifal_index, label,
414				     nlh->nlmsg_flags & NLM_F_REPLACE);
415		break;
416	case RTM_DELADDRLABEL:
417		err = ip6addrlbl_del(net, pfx, ifal->ifal_prefixlen,
418				     ifal->ifal_index);
419		break;
420	default:
421		err = -EOPNOTSUPP;
422	}
423	return err;
424}
425
426static void ip6addrlbl_putmsg(struct nlmsghdr *nlh,
427			      int prefixlen, int ifindex, u32 lseq)
428{
429	struct ifaddrlblmsg *ifal = nlmsg_data(nlh);
430	ifal->ifal_family = AF_INET6;
431	ifal->__ifal_reserved = 0;
432	ifal->ifal_prefixlen = prefixlen;
433	ifal->ifal_flags = 0;
434	ifal->ifal_index = ifindex;
435	ifal->ifal_seq = lseq;
436};
437
438static int ip6addrlbl_fill(struct sk_buff *skb,
439			   const struct ip6addrlbl_entry *p,
440			   u32 lseq,
441			   u32 portid, u32 seq, int event,
442			   unsigned int flags)
443{
444	struct nlmsghdr *nlh = nlmsg_put(skb, portid, seq, event,
445					 sizeof(struct ifaddrlblmsg), flags);
446	if (!nlh)
447		return -EMSGSIZE;
448
449	ip6addrlbl_putmsg(nlh, p->prefixlen, p->ifindex, lseq);
450
451	if (nla_put_in6_addr(skb, IFAL_ADDRESS, &p->prefix) < 0 ||
452	    nla_put_u32(skb, IFAL_LABEL, p->label) < 0) {
453		nlmsg_cancel(skb, nlh);
454		return -EMSGSIZE;
455	}
456
457	nlmsg_end(skb, nlh);
458	return 0;
459}
460
461static int ip6addrlbl_valid_dump_req(const struct nlmsghdr *nlh,
462				     struct netlink_ext_ack *extack)
463{
464	struct ifaddrlblmsg *ifal;
465
466	ifal = nlmsg_payload(nlh, sizeof(*ifal));
467	if (!ifal) {
468		NL_SET_ERR_MSG_MOD(extack, "Invalid header for address label dump request");
469		return -EINVAL;
470	}
471
472	if (ifal->__ifal_reserved || ifal->ifal_prefixlen ||
473	    ifal->ifal_flags || ifal->ifal_index || ifal->ifal_seq) {
474		NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for address label dump request");
475		return -EINVAL;
476	}
477
478	if (nlmsg_attrlen(nlh, sizeof(*ifal))) {
479		NL_SET_ERR_MSG_MOD(extack, "Invalid data after header for address label dump request");
480		return -EINVAL;
481	}
482
483	return 0;
484}
485
486static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
487{
488	const struct nlmsghdr *nlh = cb->nlh;
489	struct net *net = sock_net(skb->sk);
490	struct ip6addrlbl_entry *p;
491	int idx = 0, s_idx = cb->args[0];
492	int err = 0;
493	u32 lseq;
494
495	if (cb->strict_check) {
496		err = ip6addrlbl_valid_dump_req(nlh, cb->extack);
497		if (err < 0)
498			return err;
499	}
500
501	rcu_read_lock();
502	lseq = READ_ONCE(net->ipv6.ip6addrlbl_table.seq);
503	hlist_for_each_entry_rcu(p, &net->ipv6.ip6addrlbl_table.head, list) {
504		if (idx >= s_idx) {
505			err = ip6addrlbl_fill(skb, p,
506					      lseq,
507					      NETLINK_CB(cb->skb).portid,
508					      nlh->nlmsg_seq,
509					      RTM_NEWADDRLABEL,
510					      NLM_F_MULTI);
511			if (err < 0)
512				break;
513		}
514		idx++;
515	}
516	rcu_read_unlock();
517	cb->args[0] = idx;
518	return err;
519}
520
521static inline int ip6addrlbl_msgsize(void)
522{
523	return NLMSG_ALIGN(sizeof(struct ifaddrlblmsg))
524		+ nla_total_size(16)	/* IFAL_ADDRESS */
525		+ nla_total_size(4);	/* IFAL_LABEL */
526}
527
528static int ip6addrlbl_valid_get_req(struct sk_buff *skb,
529				    const struct nlmsghdr *nlh,
530				    struct nlattr **tb,
531				    struct netlink_ext_ack *extack)
532{
533	struct ifaddrlblmsg *ifal;
534	int i, err;
535
536	ifal = nlmsg_payload(nlh, sizeof(*ifal));
537	if (!ifal) {
538		NL_SET_ERR_MSG_MOD(extack, "Invalid header for addrlabel get request");
539		return -EINVAL;
540	}
541
542	if (!netlink_strict_get_check(skb))
543		return nlmsg_parse_deprecated(nlh, sizeof(*ifal), tb,
544					      IFAL_MAX, ifal_policy, extack);
545
546	if (ifal->__ifal_reserved || ifal->ifal_flags || ifal->ifal_seq) {
547		NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for addrlabel get request");
548		return -EINVAL;
549	}
550
551	err = nlmsg_parse_deprecated_strict(nlh, sizeof(*ifal), tb, IFAL_MAX,
552					    ifal_policy, extack);
553	if (err)
554		return err;
555
556	for (i = 0; i <= IFAL_MAX; i++) {
557		if (!tb[i])
558			continue;
559
560		switch (i) {
561		case IFAL_ADDRESS:
562			break;
563		default:
564			NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in addrlabel get request");
565			return -EINVAL;
566		}
567	}
568
569	return 0;
570}
571
572static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
573			  struct netlink_ext_ack *extack)
574{
575	struct net *net = sock_net(in_skb->sk);
576	struct ifaddrlblmsg *ifal;
577	struct nlattr *tb[IFAL_MAX+1];
578	struct in6_addr *addr;
579	u32 lseq;
580	int err = 0;
581	struct ip6addrlbl_entry *p;
582	struct sk_buff *skb;
583
584	err = ip6addrlbl_valid_get_req(in_skb, nlh, tb, extack);
585	if (err < 0)
586		return err;
587
588	ifal = nlmsg_data(nlh);
589
590	if (ifal->ifal_family != AF_INET6 ||
591	    ifal->ifal_prefixlen != 128)
592		return -EINVAL;
593
594	if (ifal->ifal_index &&
595	    !addrlbl_ifindex_exists(net, ifal->ifal_index))
596		return -EINVAL;
597
598	if (!tb[IFAL_ADDRESS])
599		return -EINVAL;
600	addr = nla_data(tb[IFAL_ADDRESS]);
601
602	skb = nlmsg_new(ip6addrlbl_msgsize(), GFP_KERNEL);
603	if (!skb)
604		return -ENOBUFS;
605
606	err = -ESRCH;
607
608	rcu_read_lock();
609	p = __ipv6_addr_label(net, addr, ipv6_addr_type(addr), ifal->ifal_index);
610	lseq = READ_ONCE(net->ipv6.ip6addrlbl_table.seq);
611	if (p)
612		err = ip6addrlbl_fill(skb, p, lseq,
613				      NETLINK_CB(in_skb).portid,
614				      nlh->nlmsg_seq,
615				      RTM_NEWADDRLABEL, 0);
616	rcu_read_unlock();
617
618	if (err < 0) {
619		WARN_ON(err == -EMSGSIZE);
620		kfree_skb(skb);
621	} else {
622		err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
623	}
624	return err;
625}
626
627static const struct rtnl_msg_handler ipv6_adddr_label_rtnl_msg_handlers[] __initconst_or_module = {
628	{.owner = THIS_MODULE, .protocol = PF_INET6, .msgtype = RTM_NEWADDRLABEL,
629	 .doit = ip6addrlbl_newdel, .flags = RTNL_FLAG_DOIT_UNLOCKED},
630	{.owner = THIS_MODULE, .protocol = PF_INET6, .msgtype = RTM_DELADDRLABEL,
631	 .doit = ip6addrlbl_newdel, .flags = RTNL_FLAG_DOIT_UNLOCKED},
632	{.owner = THIS_MODULE, .protocol = PF_INET6, .msgtype = RTM_GETADDRLABEL,
633	 .doit = ip6addrlbl_get, .dumpit = ip6addrlbl_dump,
634	 .flags = RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED},
635};
636
637int __init ipv6_addr_label_rtnl_register(void)
638{
639	return rtnl_register_many(ipv6_adddr_label_rtnl_msg_handlers);
640}