addrlabel.c revision f32138319ca6541e65f95f8e17c9cc88ac1baf94 
1/*
2 * IPv6 Address Label subsystem
3 * for the IPv6 "Default" Source Address Selection
4 *
5 * Copyright (C)2007 USAGI/WIDE Project
6 */
7/*
8 * Author:
9 * 	YOSHIFUJI Hideaki @ USAGI/WIDE Project <yoshfuji@linux-ipv6.org>
10 */
11
12#include <linux/kernel.h>
13#include <linux/list.h>
14#include <linux/rcupdate.h>
15#include <linux/in6.h>
16#include <linux/slab.h>
17#include <net/addrconf.h>
18#include <linux/if_addrlabel.h>
19#include <linux/netlink.h>
20#include <linux/rtnetlink.h>
21
22#if 0
23#define ADDRLABEL(x...) printk(x)
24#else
25#define ADDRLABEL(x...) do { ; } while(0)
26#endif
27
28/*
29 * Policy Table
30 */
31struct ip6addrlbl_entry
32{
33#ifdef CONFIG_NET_NS
34	struct net *lbl_net;
35#endif
36	struct in6_addr prefix;
37	int prefixlen;
38	int ifindex;
39	int addrtype;
40	u32 label;
41	struct hlist_node list;
42	atomic_t refcnt;
43	struct rcu_head rcu;
44};
45
46static struct ip6addrlbl_table
47{
48	struct hlist_head head;
49	spinlock_t lock;
50	u32 seq;
51} ip6addrlbl_table;
52
53static inline
54struct net *ip6addrlbl_net(const struct ip6addrlbl_entry *lbl)
55{
56	return read_pnet(&lbl->lbl_net);
57}
58
59/*
60 * Default policy table (RFC3484 + extensions)
61 *
62 * prefix		addr_type	label
63 * -------------------------------------------------------------------------
64 * ::1/128		LOOPBACK	0
65 * ::/0			N/A		1
66 * 2002::/16		N/A		2
67 * ::/96		COMPATv4	3
68 * ::ffff:0:0/96	V4MAPPED	4
69 * fc00::/7		N/A		5		ULA (RFC 4193)
70 * 2001::/32		N/A		6		Teredo (RFC 4380)
71 * 2001:10::/28		N/A		7		ORCHID (RFC 4843)
72 *
73 * Note: 0xffffffff is used if we do not have any policies.
74 */
75
76#define IPV6_ADDR_LABEL_DEFAULT	0xffffffffUL
77
78static const __net_initdata struct ip6addrlbl_init_table
79{
80	const struct in6_addr *prefix;
81	int prefixlen;
82	u32 label;
83} ip6addrlbl_init_table[] = {
84	{	/* ::/0 */
85		.prefix = &in6addr_any,
86		.label = 1,
87	},{	/* fc00::/7 */
88		.prefix = &(struct in6_addr){{{ 0xfc }}},
89		.prefixlen = 7,
90		.label = 5,
91	},{	/* 2002::/16 */
92		.prefix = &(struct in6_addr){{{ 0x20, 0x02 }}},
93		.prefixlen = 16,
94		.label = 2,
95	},{	/* 2001::/32 */
96		.prefix = &(struct in6_addr){{{ 0x20, 0x01 }}},
97		.prefixlen = 32,
98		.label = 6,
99	},{	/* 2001:10::/28 */
100		.prefix = &(struct in6_addr){{{ 0x20, 0x01, 0x00, 0x10 }}},
101		.prefixlen = 28,
102		.label = 7,
103	},{	/* ::ffff:0:0 */
104		.prefix = &(struct in6_addr){{{ [10] = 0xff, [11] = 0xff }}},
105		.prefixlen = 96,
106		.label = 4,
107	},{	/* ::/96 */
108		.prefix = &in6addr_any,
109		.prefixlen = 96,
110		.label = 3,
111	},{	/* ::1/128 */
112		.prefix = &in6addr_loopback,
113		.prefixlen = 128,
114		.label = 0,
115	}
116};
117
118/* Object management */
119static inline void ip6addrlbl_free(struct ip6addrlbl_entry *p)
120{
121#ifdef CONFIG_NET_NS
122	release_net(p->lbl_net);
123#endif
124	kfree(p);
125}
126
127static void ip6addrlbl_free_rcu(struct rcu_head *h)
128{
129	ip6addrlbl_free(container_of(h, struct ip6addrlbl_entry, rcu));
130}
131
132static inline int ip6addrlbl_hold(struct ip6addrlbl_entry *p)
133{
134	return atomic_inc_not_zero(&p->refcnt);
135}
136
137static inline void ip6addrlbl_put(struct ip6addrlbl_entry *p)
138{
139	if (atomic_dec_and_test(&p->refcnt))
140		call_rcu(&p->rcu, ip6addrlbl_free_rcu);
141}
142
143/* Find label */
144static int __ip6addrlbl_match(struct net *net,
145			      struct ip6addrlbl_entry *p,
146			      const struct in6_addr *addr,
147			      int addrtype, int ifindex)
148{
149	if (!net_eq(ip6addrlbl_net(p), net))
150		return 0;
151	if (p->ifindex && p->ifindex != ifindex)
152		return 0;
153	if (p->addrtype && p->addrtype != addrtype)
154		return 0;
155	if (!ipv6_prefix_equal(addr, &p->prefix, p->prefixlen))
156		return 0;
157	return 1;
158}
159
160static struct ip6addrlbl_entry *__ipv6_addr_label(struct net *net,
161						  const struct in6_addr *addr,
162						  int type, int ifindex)
163{
164	struct hlist_node *pos;
165	struct ip6addrlbl_entry *p;
166	hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
167		if (__ip6addrlbl_match(net, p, addr, type, ifindex))
168			return p;
169	}
170	return NULL;
171}
172
173u32 ipv6_addr_label(struct net *net,
174		    const struct in6_addr *addr, int type, int ifindex)
175{
176	u32 label;
177	struct ip6addrlbl_entry *p;
178
179	type &= IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK;
180
181	rcu_read_lock();
182	p = __ipv6_addr_label(net, addr, type, ifindex);
183	label = p ? p->label : IPV6_ADDR_LABEL_DEFAULT;
184	rcu_read_unlock();
185
186	ADDRLABEL(KERN_DEBUG "%s(addr=%pI6, type=%d, ifindex=%d) => %08x\n",
187		  __func__, addr, type, ifindex, label);
188
189	return label;
190}
191
192/* allocate one entry */
193static struct ip6addrlbl_entry *ip6addrlbl_alloc(struct net *net,
194						 const struct in6_addr *prefix,
195						 int prefixlen, int ifindex,
196						 u32 label)
197{
198	struct ip6addrlbl_entry *newp;
199	int addrtype;
200
201	ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d, label=%u)\n",
202		  __func__, prefix, prefixlen, ifindex, (unsigned int)label);
203
204	addrtype = ipv6_addr_type(prefix) & (IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK);
205
206	switch (addrtype) {
207	case IPV6_ADDR_MAPPED:
208		if (prefixlen > 96)
209			return ERR_PTR(-EINVAL);
210		if (prefixlen < 96)
211			addrtype = 0;
212		break;
213	case IPV6_ADDR_COMPATv4:
214		if (prefixlen != 96)
215			addrtype = 0;
216		break;
217	case IPV6_ADDR_LOOPBACK:
218		if (prefixlen != 128)
219			addrtype = 0;
220		break;
221	}
222
223	newp = kmalloc(sizeof(*newp), GFP_KERNEL);
224	if (!newp)
225		return ERR_PTR(-ENOMEM);
226
227	ipv6_addr_prefix(&newp->prefix, prefix, prefixlen);
228	newp->prefixlen = prefixlen;
229	newp->ifindex = ifindex;
230	newp->addrtype = addrtype;
231	newp->label = label;
232	INIT_HLIST_NODE(&newp->list);
233#ifdef CONFIG_NET_NS
234	newp->lbl_net = hold_net(net);
235#endif
236	atomic_set(&newp->refcnt, 1);
237	return newp;
238}
239
240/* add a label */
241static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
242{
243	int ret = 0;
244
245	ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n",
246			__func__,
247			newp, replace);
248
249	if (hlist_empty(&ip6addrlbl_table.head)) {
250		hlist_add_head_rcu(&newp->list, &ip6addrlbl_table.head);
251	} else {
252		struct hlist_node *pos, *n;
253		struct ip6addrlbl_entry *p = NULL;
254		hlist_for_each_entry_safe(p, pos, n,
255					  &ip6addrlbl_table.head, list) {
256			if (p->prefixlen == newp->prefixlen &&
257			    net_eq(ip6addrlbl_net(p), ip6addrlbl_net(newp)) &&
258			    p->ifindex == newp->ifindex &&
259			    ipv6_addr_equal(&p->prefix, &newp->prefix)) {
260				if (!replace) {
261					ret = -EEXIST;
262					goto out;
263				}
264				hlist_replace_rcu(&p->list, &newp->list);
265				ip6addrlbl_put(p);
266				goto out;
267			} else if ((p->prefixlen == newp->prefixlen && !p->ifindex) ||
268				   (p->prefixlen < newp->prefixlen)) {
269				hlist_add_before_rcu(&newp->list, &p->list);
270				goto out;
271			}
272		}
273		hlist_add_after_rcu(&p->list, &newp->list);
274	}
275out:
276	if (!ret)
277		ip6addrlbl_table.seq++;
278	return ret;
279}
280
281/* add a label */
282static int ip6addrlbl_add(struct net *net,
283			  const struct in6_addr *prefix, int prefixlen,
284			  int ifindex, u32 label, int replace)
285{
286	struct ip6addrlbl_entry *newp;
287	int ret = 0;
288
289	ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d, label=%u, replace=%d)\n",
290		  __func__, prefix, prefixlen, ifindex, (unsigned int)label,
291		  replace);
292
293	newp = ip6addrlbl_alloc(net, prefix, prefixlen, ifindex, label);
294	if (IS_ERR(newp))
295		return PTR_ERR(newp);
296	spin_lock(&ip6addrlbl_table.lock);
297	ret = __ip6addrlbl_add(newp, replace);
298	spin_unlock(&ip6addrlbl_table.lock);
299	if (ret)
300		ip6addrlbl_free(newp);
301	return ret;
302}
303
304/* remove a label */
305static int __ip6addrlbl_del(struct net *net,
306			    const struct in6_addr *prefix, int prefixlen,
307			    int ifindex)
308{
309	struct ip6addrlbl_entry *p = NULL;
310	struct hlist_node *pos, *n;
311	int ret = -ESRCH;
312
313	ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n",
314		  __func__, prefix, prefixlen, ifindex);
315
316	hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
317		if (p->prefixlen == prefixlen &&
318		    net_eq(ip6addrlbl_net(p), net) &&
319		    p->ifindex == ifindex &&
320		    ipv6_addr_equal(&p->prefix, prefix)) {
321			hlist_del_rcu(&p->list);
322			ip6addrlbl_put(p);
323			ret = 0;
324			break;
325		}
326	}
327	return ret;
328}
329
330static int ip6addrlbl_del(struct net *net,
331			  const struct in6_addr *prefix, int prefixlen,
332			  int ifindex)
333{
334	struct in6_addr prefix_buf;
335	int ret;
336
337	ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n",
338		  __func__, prefix, prefixlen, ifindex);
339
340	ipv6_addr_prefix(&prefix_buf, prefix, prefixlen);
341	spin_lock(&ip6addrlbl_table.lock);
342	ret = __ip6addrlbl_del(net, &prefix_buf, prefixlen, ifindex);
343	spin_unlock(&ip6addrlbl_table.lock);
344	return ret;
345}
346
347/* add default label */
348static int __net_init ip6addrlbl_net_init(struct net *net)
349{
350	int err = 0;
351	int i;
352
353	ADDRLABEL(KERN_DEBUG "%s\n", __func__);
354
355	for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) {
356		int ret = ip6addrlbl_add(net,
357					 ip6addrlbl_init_table[i].prefix,
358					 ip6addrlbl_init_table[i].prefixlen,
359					 0,
360					 ip6addrlbl_init_table[i].label, 0);
361		/* XXX: should we free all rules when we catch an error? */
362		if (ret && (!err || err != -ENOMEM))
363			err = ret;
364	}
365	return err;
366}
367
368static void __net_exit ip6addrlbl_net_exit(struct net *net)
369{
370	struct ip6addrlbl_entry *p = NULL;
371	struct hlist_node *pos, *n;
372
373	/* Remove all labels belonging to the exiting net */
374	spin_lock(&ip6addrlbl_table.lock);
375	hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
376		if (net_eq(ip6addrlbl_net(p), net)) {
377			hlist_del_rcu(&p->list);
378			ip6addrlbl_put(p);
379		}
380	}
381	spin_unlock(&ip6addrlbl_table.lock);
382}
383
384static struct pernet_operations ipv6_addr_label_ops = {
385	.init = ip6addrlbl_net_init,
386	.exit = ip6addrlbl_net_exit,
387};
388
389int __init ipv6_addr_label_init(void)
390{
391	spin_lock_init(&ip6addrlbl_table.lock);
392
393	return register_pernet_subsys(&ipv6_addr_label_ops);
394}
395
396void ipv6_addr_label_cleanup(void)
397{
398	unregister_pernet_subsys(&ipv6_addr_label_ops);
399}
400
401static const struct nla_policy ifal_policy[IFAL_MAX+1] = {
402	[IFAL_ADDRESS]		= { .len = sizeof(struct in6_addr), },
403	[IFAL_LABEL]		= { .len = sizeof(u32), },
404};
405
406static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh,
407			     void *arg)
408{
409	struct net *net = sock_net(skb->sk);
410	struct ifaddrlblmsg *ifal;
411	struct nlattr *tb[IFAL_MAX+1];
412	struct in6_addr *pfx;
413	u32 label;
414	int err = 0;
415
416	err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
417	if (err < 0)
418		return err;
419
420	ifal = nlmsg_data(nlh);
421
422	if (ifal->ifal_family != AF_INET6 ||
423	    ifal->ifal_prefixlen > 128)
424		return -EINVAL;
425
426	if (!tb[IFAL_ADDRESS])
427		return -EINVAL;
428
429	pfx = nla_data(tb[IFAL_ADDRESS]);
430	if (!pfx)
431		return -EINVAL;
432
433	if (!tb[IFAL_LABEL])
434		return -EINVAL;
435	label = nla_get_u32(tb[IFAL_LABEL]);
436	if (label == IPV6_ADDR_LABEL_DEFAULT)
437		return -EINVAL;
438
439	switch(nlh->nlmsg_type) {
440	case RTM_NEWADDRLABEL:
441		if (ifal->ifal_index &&
442		    !__dev_get_by_index(net, ifal->ifal_index))
443			return -EINVAL;
444
445		err = ip6addrlbl_add(net, pfx, ifal->ifal_prefixlen,
446				     ifal->ifal_index, label,
447				     nlh->nlmsg_flags & NLM_F_REPLACE);
448		break;
449	case RTM_DELADDRLABEL:
450		err = ip6addrlbl_del(net, pfx, ifal->ifal_prefixlen,
451				     ifal->ifal_index);
452		break;
453	default:
454		err = -EOPNOTSUPP;
455	}
456	return err;
457}
458
459static inline void ip6addrlbl_putmsg(struct nlmsghdr *nlh,
460				     int prefixlen, int ifindex, u32 lseq)
461{
462	struct ifaddrlblmsg *ifal = nlmsg_data(nlh);
463	ifal->ifal_family = AF_INET6;
464	ifal->ifal_prefixlen = prefixlen;
465	ifal->ifal_flags = 0;
466	ifal->ifal_index = ifindex;
467	ifal->ifal_seq = lseq;
468};
469
470static int ip6addrlbl_fill(struct sk_buff *skb,
471			   struct ip6addrlbl_entry *p,
472			   u32 lseq,
473			   u32 pid, u32 seq, int event,
474			   unsigned int flags)
475{
476	struct nlmsghdr *nlh = nlmsg_put(skb, pid, seq, event,
477					 sizeof(struct ifaddrlblmsg), flags);
478	if (!nlh)
479		return -EMSGSIZE;
480
481	ip6addrlbl_putmsg(nlh, p->prefixlen, p->ifindex, lseq);
482
483	if (nla_put(skb, IFAL_ADDRESS, 16, &p->prefix) < 0 ||
484	    nla_put_u32(skb, IFAL_LABEL, p->label) < 0) {
485		nlmsg_cancel(skb, nlh);
486		return -EMSGSIZE;
487	}
488
489	return nlmsg_end(skb, nlh);
490}
491
492static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
493{
494	struct net *net = sock_net(skb->sk);
495	struct ip6addrlbl_entry *p;
496	struct hlist_node *pos;
497	int idx = 0, s_idx = cb->args[0];
498	int err;
499
500	rcu_read_lock();
501	hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
502		if (idx >= s_idx &&
503		    net_eq(ip6addrlbl_net(p), net)) {
504			if ((err = ip6addrlbl_fill(skb, p,
505						   ip6addrlbl_table.seq,
506						   NETLINK_CB(cb->skb).pid,
507						   cb->nlh->nlmsg_seq,
508						   RTM_NEWADDRLABEL,
509						   NLM_F_MULTI)) <= 0)
510				break;
511		}
512		idx++;
513	}
514	rcu_read_unlock();
515	cb->args[0] = idx;
516	return skb->len;
517}
518
519static inline int ip6addrlbl_msgsize(void)
520{
521	return NLMSG_ALIGN(sizeof(struct ifaddrlblmsg))
522		+ nla_total_size(16)	/* IFAL_ADDRESS */
523		+ nla_total_size(4);	/* IFAL_LABEL */
524}
525
526static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr* nlh,
527			  void *arg)
528{
529	struct net *net = sock_net(in_skb->sk);
530	struct ifaddrlblmsg *ifal;
531	struct nlattr *tb[IFAL_MAX+1];
532	struct in6_addr *addr;
533	u32 lseq;
534	int err = 0;
535	struct ip6addrlbl_entry *p;
536	struct sk_buff *skb;
537
538	err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
539	if (err < 0)
540		return err;
541
542	ifal = nlmsg_data(nlh);
543
544	if (ifal->ifal_family != AF_INET6 ||
545	    ifal->ifal_prefixlen != 128)
546		return -EINVAL;
547
548	if (ifal->ifal_index &&
549	    !__dev_get_by_index(net, ifal->ifal_index))
550		return -EINVAL;
551
552	if (!tb[IFAL_ADDRESS])
553		return -EINVAL;
554
555	addr = nla_data(tb[IFAL_ADDRESS]);
556	if (!addr)
557		return -EINVAL;
558
559	rcu_read_lock();
560	p = __ipv6_addr_label(net, addr, ipv6_addr_type(addr), ifal->ifal_index);
561	if (p && ip6addrlbl_hold(p))
562		p = NULL;
563	lseq = ip6addrlbl_table.seq;
564	rcu_read_unlock();
565
566	if (!p) {
567		err = -ESRCH;
568		goto out;
569	}
570
571	if (!(skb = nlmsg_new(ip6addrlbl_msgsize(), GFP_KERNEL))) {
572		ip6addrlbl_put(p);
573		return -ENOBUFS;
574	}
575
576	err = ip6addrlbl_fill(skb, p, lseq,
577			      NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
578			      RTM_NEWADDRLABEL, 0);
579
580	ip6addrlbl_put(p);
581
582	if (err < 0) {
583		WARN_ON(err == -EMSGSIZE);
584		kfree_skb(skb);
585		goto out;
586	}
587
588	err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
589out:
590	return err;
591}
592
593void __init ipv6_addr_label_rtnl_register(void)
594{
595	__rtnl_register(PF_INET6, RTM_NEWADDRLABEL, ip6addrlbl_newdel,
596			NULL, NULL);
597	__rtnl_register(PF_INET6, RTM_DELADDRLABEL, ip6addrlbl_newdel,
598			NULL, NULL);
599	__rtnl_register(PF_INET6, RTM_GETADDRLABEL, ip6addrlbl_get,
600			ip6addrlbl_dump, NULL);
601}
602
603