addrlabel.c revision 3de232554a91adc74e80dc15c304be806bd7e1f9 
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 <net/addrconf.h>
17#include <linux/if_addrlabel.h>
18#include <linux/netlink.h>
19#include <linux/rtnetlink.h>
20
21#if 0
22#define ADDRLABEL(x...) printk(x)
23#else
24#define ADDRLABEL(x...) do { ; } while(0)
25#endif
26
27/*
28 * Policy Table
29 */
30struct ip6addrlbl_entry
31{
32#ifdef CONFIG_NET_NS
33	struct net *lbl_net;
34#endif
35	struct in6_addr prefix;
36	int prefixlen;
37	int ifindex;
38	int addrtype;
39	u32 label;
40	struct hlist_node list;
41	atomic_t refcnt;
42	struct rcu_head rcu;
43};
44
45static struct ip6addrlbl_table
46{
47	struct hlist_head head;
48	spinlock_t lock;
49	u32 seq;
50} ip6addrlbl_table;
51
52static inline
53struct net *ip6addrlbl_net(const struct ip6addrlbl_entry *lbl)
54{
55#ifdef CONFIG_NET_NS
56	return lbl->lbl_net;
57#else
58	return &init_net;
59#endif
60}
61
62/*
63 * Default policy table (RFC3484 + extensions)
64 *
65 * prefix		addr_type	label
66 * -------------------------------------------------------------------------
67 * ::1/128		LOOPBACK	0
68 * ::/0			N/A		1
69 * 2002::/16		N/A		2
70 * ::/96		COMPATv4	3
71 * ::ffff:0:0/96	V4MAPPED	4
72 * fc00::/7		N/A		5		ULA (RFC 4193)
73 * 2001::/32		N/A		6		Teredo (RFC 4380)
74 * 2001:10::/28		N/A		7		ORCHID (RFC 4843)
75 *
76 * Note: 0xffffffff is used if we do not have any policies.
77 */
78
79#define IPV6_ADDR_LABEL_DEFAULT	0xffffffffUL
80
81static const __net_initdata struct ip6addrlbl_init_table
82{
83	const struct in6_addr *prefix;
84	int prefixlen;
85	u32 label;
86} ip6addrlbl_init_table[] = {
87	{	/* ::/0 */
88		.prefix = &in6addr_any,
89		.label = 1,
90	},{	/* fc00::/7 */
91		.prefix = &(struct in6_addr){{{ 0xfc }}},
92		.prefixlen = 7,
93		.label = 5,
94	},{	/* 2002::/16 */
95		.prefix = &(struct in6_addr){{{ 0x20, 0x02 }}},
96		.prefixlen = 16,
97		.label = 2,
98	},{	/* 2001::/32 */
99		.prefix = &(struct in6_addr){{{ 0x20, 0x01 }}},
100		.prefixlen = 32,
101		.label = 6,
102	},{	/* 2001:10::/28 */
103		.prefix = &(struct in6_addr){{{ 0x20, 0x01, 0x00, 0x10 }}},
104		.prefixlen = 28,
105		.label = 7,
106	},{	/* ::ffff:0:0 */
107		.prefix = &(struct in6_addr){{{ [10] = 0xff, [11] = 0xff }}},
108		.prefixlen = 96,
109		.label = 4,
110	},{	/* ::/96 */
111		.prefix = &in6addr_any,
112		.prefixlen = 96,
113		.label = 3,
114	},{	/* ::1/128 */
115		.prefix = &in6addr_loopback,
116		.prefixlen = 128,
117		.label = 0,
118	}
119};
120
121/* Object management */
122static inline void ip6addrlbl_free(struct ip6addrlbl_entry *p)
123{
124#ifdef CONFIG_NET_NS
125	release_net(p->lbl_net);
126#endif
127	kfree(p);
128}
129
130static void ip6addrlbl_free_rcu(struct rcu_head *h)
131{
132	ip6addrlbl_free(container_of(h, struct ip6addrlbl_entry, rcu));
133}
134
135static inline int ip6addrlbl_hold(struct ip6addrlbl_entry *p)
136{
137	return atomic_inc_not_zero(&p->refcnt);
138}
139
140static inline void ip6addrlbl_put(struct ip6addrlbl_entry *p)
141{
142	if (atomic_dec_and_test(&p->refcnt))
143		call_rcu(&p->rcu, ip6addrlbl_free_rcu);
144}
145
146/* Find label */
147static int __ip6addrlbl_match(struct net *net,
148			      struct ip6addrlbl_entry *p,
149			      const struct in6_addr *addr,
150			      int addrtype, int ifindex)
151{
152	if (!net_eq(ip6addrlbl_net(p), net))
153		return 0;
154	if (p->ifindex && p->ifindex != ifindex)
155		return 0;
156	if (p->addrtype && p->addrtype != addrtype)
157		return 0;
158	if (!ipv6_prefix_equal(addr, &p->prefix, p->prefixlen))
159		return 0;
160	return 1;
161}
162
163static struct ip6addrlbl_entry *__ipv6_addr_label(struct net *net,
164						  const struct in6_addr *addr,
165						  int type, int ifindex)
166{
167	struct hlist_node *pos;
168	struct ip6addrlbl_entry *p;
169	hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
170		if (__ip6addrlbl_match(net, p, addr, type, ifindex))
171			return p;
172	}
173	return NULL;
174}
175
176u32 ipv6_addr_label(struct net *net,
177		    const struct in6_addr *addr, int type, int ifindex)
178{
179	u32 label;
180	struct ip6addrlbl_entry *p;
181
182	type &= IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK;
183
184	rcu_read_lock();
185	p = __ipv6_addr_label(net, addr, type, ifindex);
186	label = p ? p->label : IPV6_ADDR_LABEL_DEFAULT;
187	rcu_read_unlock();
188
189	ADDRLABEL(KERN_DEBUG "%s(addr=" NIP6_FMT ", type=%d, ifindex=%d) => %08x\n",
190			__func__,
191			NIP6(*addr), type, ifindex,
192			label);
193
194	return label;
195}
196
197/* allocate one entry */
198static struct ip6addrlbl_entry *ip6addrlbl_alloc(struct net *net,
199						 const struct in6_addr *prefix,
200						 int prefixlen, int ifindex,
201						 u32 label)
202{
203	struct ip6addrlbl_entry *newp;
204	int addrtype;
205
206	ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d, label=%u)\n",
207			__func__,
208			NIP6(*prefix), prefixlen,
209			ifindex,
210			(unsigned int)label);
211
212	addrtype = ipv6_addr_type(prefix) & (IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK);
213
214	switch (addrtype) {
215	case IPV6_ADDR_MAPPED:
216		if (prefixlen > 96)
217			return ERR_PTR(-EINVAL);
218		if (prefixlen < 96)
219			addrtype = 0;
220		break;
221	case IPV6_ADDR_COMPATv4:
222		if (prefixlen != 96)
223			addrtype = 0;
224		break;
225	case IPV6_ADDR_LOOPBACK:
226		if (prefixlen != 128)
227			addrtype = 0;
228		break;
229	}
230
231	newp = kmalloc(sizeof(*newp), GFP_KERNEL);
232	if (!newp)
233		return ERR_PTR(-ENOMEM);
234
235	ipv6_addr_prefix(&newp->prefix, prefix, prefixlen);
236	newp->prefixlen = prefixlen;
237	newp->ifindex = ifindex;
238	newp->addrtype = addrtype;
239	newp->label = label;
240	INIT_HLIST_NODE(&newp->list);
241#ifdef CONFIG_NET_NS
242	newp->lbl_net = hold_net(net);
243#endif
244	atomic_set(&newp->refcnt, 1);
245	return newp;
246}
247
248/* add a label */
249static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
250{
251	int ret = 0;
252
253	ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n",
254			__func__,
255			newp, replace);
256
257	if (hlist_empty(&ip6addrlbl_table.head)) {
258		hlist_add_head_rcu(&newp->list, &ip6addrlbl_table.head);
259	} else {
260		struct hlist_node *pos, *n;
261		struct ip6addrlbl_entry *p = NULL;
262		hlist_for_each_entry_safe(p, pos, n,
263					  &ip6addrlbl_table.head, list) {
264			if (p->prefixlen == newp->prefixlen &&
265			    net_eq(ip6addrlbl_net(p), ip6addrlbl_net(newp)) &&
266			    p->ifindex == newp->ifindex &&
267			    ipv6_addr_equal(&p->prefix, &newp->prefix)) {
268				if (!replace) {
269					ret = -EEXIST;
270					goto out;
271				}
272				hlist_replace_rcu(&p->list, &newp->list);
273				ip6addrlbl_put(p);
274				goto out;
275			} else if ((p->prefixlen == newp->prefixlen && !p->ifindex) ||
276				   (p->prefixlen < newp->prefixlen)) {
277				hlist_add_before_rcu(&newp->list, &p->list);
278				goto out;
279			}
280		}
281		hlist_add_after_rcu(&p->list, &newp->list);
282	}
283out:
284	if (!ret)
285		ip6addrlbl_table.seq++;
286	return ret;
287}
288
289/* add a label */
290static int ip6addrlbl_add(struct net *net,
291			  const struct in6_addr *prefix, int prefixlen,
292			  int ifindex, u32 label, int replace)
293{
294	struct ip6addrlbl_entry *newp;
295	int ret = 0;
296
297	ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d, label=%u, replace=%d)\n",
298			__func__,
299			NIP6(*prefix), prefixlen,
300			ifindex,
301			(unsigned int)label,
302			replace);
303
304	newp = ip6addrlbl_alloc(net, prefix, prefixlen, ifindex, label);
305	if (IS_ERR(newp))
306		return PTR_ERR(newp);
307	spin_lock(&ip6addrlbl_table.lock);
308	ret = __ip6addrlbl_add(newp, replace);
309	spin_unlock(&ip6addrlbl_table.lock);
310	if (ret)
311		ip6addrlbl_free(newp);
312	return ret;
313}
314
315/* remove a label */
316static int __ip6addrlbl_del(struct net *net,
317			    const struct in6_addr *prefix, int prefixlen,
318			    int ifindex)
319{
320	struct ip6addrlbl_entry *p = NULL;
321	struct hlist_node *pos, *n;
322	int ret = -ESRCH;
323
324	ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d)\n",
325			__func__,
326			NIP6(*prefix), prefixlen,
327			ifindex);
328
329	hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
330		if (p->prefixlen == prefixlen &&
331		    net_eq(ip6addrlbl_net(p), net) &&
332		    p->ifindex == ifindex &&
333		    ipv6_addr_equal(&p->prefix, prefix)) {
334			hlist_del_rcu(&p->list);
335			ip6addrlbl_put(p);
336			ret = 0;
337			break;
338		}
339	}
340	return ret;
341}
342
343static int ip6addrlbl_del(struct net *net,
344			  const struct in6_addr *prefix, int prefixlen,
345			  int ifindex)
346{
347	struct in6_addr prefix_buf;
348	int ret;
349
350	ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d)\n",
351			__func__,
352			NIP6(*prefix), prefixlen,
353			ifindex);
354
355	ipv6_addr_prefix(&prefix_buf, prefix, prefixlen);
356	spin_lock(&ip6addrlbl_table.lock);
357	ret = __ip6addrlbl_del(net, &prefix_buf, prefixlen, ifindex);
358	spin_unlock(&ip6addrlbl_table.lock);
359	return ret;
360}
361
362/* add default label */
363static int __net_init ip6addrlbl_net_init(struct net *net)
364{
365	int err = 0;
366	int i;
367
368	ADDRLABEL(KERN_DEBUG "%s()\n", __func__);
369
370	for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) {
371		int ret = ip6addrlbl_add(net,
372					 ip6addrlbl_init_table[i].prefix,
373					 ip6addrlbl_init_table[i].prefixlen,
374					 0,
375					 ip6addrlbl_init_table[i].label, 0);
376		/* XXX: should we free all rules when we catch an error? */
377		if (ret && (!err || err != -ENOMEM))
378			err = ret;
379	}
380	return err;
381}
382
383static void __net_exit ip6addrlbl_net_exit(struct net *net)
384{
385	struct ip6addrlbl_entry *p = NULL;
386	struct hlist_node *pos, *n;
387
388	/* Remove all labels belonging to the exiting net */
389	spin_lock(&ip6addrlbl_table.lock);
390	hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
391		if (net_eq(ip6addrlbl_net(p), net)) {
392			hlist_del_rcu(&p->list);
393			ip6addrlbl_put(p);
394		}
395	}
396	spin_unlock(&ip6addrlbl_table.lock);
397}
398
399static struct pernet_operations ipv6_addr_label_ops = {
400	.init = ip6addrlbl_net_init,
401	.exit = ip6addrlbl_net_exit,
402};
403
404int __init ipv6_addr_label_init(void)
405{
406	spin_lock_init(&ip6addrlbl_table.lock);
407
408	return register_pernet_subsys(&ipv6_addr_label_ops);
409}
410
411static const struct nla_policy ifal_policy[IFAL_MAX+1] = {
412	[IFAL_ADDRESS]		= { .len = sizeof(struct in6_addr), },
413	[IFAL_LABEL]		= { .len = sizeof(u32), },
414};
415
416static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh,
417			     void *arg)
418{
419	struct net *net = sock_net(skb->sk);
420	struct ifaddrlblmsg *ifal;
421	struct nlattr *tb[IFAL_MAX+1];
422	struct in6_addr *pfx;
423	u32 label;
424	int err = 0;
425
426	err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
427	if (err < 0)
428		return err;
429
430	ifal = nlmsg_data(nlh);
431
432	if (ifal->ifal_family != AF_INET6 ||
433	    ifal->ifal_prefixlen > 128)
434		return -EINVAL;
435
436	if (ifal->ifal_index &&
437	    !__dev_get_by_index(net, ifal->ifal_index))
438		return -EINVAL;
439
440	if (!tb[IFAL_ADDRESS])
441		return -EINVAL;
442
443	pfx = nla_data(tb[IFAL_ADDRESS]);
444	if (!pfx)
445		return -EINVAL;
446
447	if (!tb[IFAL_LABEL])
448		return -EINVAL;
449	label = nla_get_u32(tb[IFAL_LABEL]);
450	if (label == IPV6_ADDR_LABEL_DEFAULT)
451		return -EINVAL;
452
453	switch(nlh->nlmsg_type) {
454	case RTM_NEWADDRLABEL:
455		err = ip6addrlbl_add(net, pfx, ifal->ifal_prefixlen,
456				     ifal->ifal_index, label,
457				     nlh->nlmsg_flags & NLM_F_REPLACE);
458		break;
459	case RTM_DELADDRLABEL:
460		err = ip6addrlbl_del(net, pfx, ifal->ifal_prefixlen,
461				     ifal->ifal_index);
462		break;
463	default:
464		err = -EOPNOTSUPP;
465	}
466	return err;
467}
468
469static inline void ip6addrlbl_putmsg(struct nlmsghdr *nlh,
470				     int prefixlen, int ifindex, u32 lseq)
471{
472	struct ifaddrlblmsg *ifal = nlmsg_data(nlh);
473	ifal->ifal_family = AF_INET6;
474	ifal->ifal_prefixlen = prefixlen;
475	ifal->ifal_flags = 0;
476	ifal->ifal_index = ifindex;
477	ifal->ifal_seq = lseq;
478};
479
480static int ip6addrlbl_fill(struct sk_buff *skb,
481			   struct ip6addrlbl_entry *p,
482			   u32 lseq,
483			   u32 pid, u32 seq, int event,
484			   unsigned int flags)
485{
486	struct nlmsghdr *nlh = nlmsg_put(skb, pid, seq, event,
487					 sizeof(struct ifaddrlblmsg), flags);
488	if (!nlh)
489		return -EMSGSIZE;
490
491	ip6addrlbl_putmsg(nlh, p->prefixlen, p->ifindex, lseq);
492
493	if (nla_put(skb, IFAL_ADDRESS, 16, &p->prefix) < 0 ||
494	    nla_put_u32(skb, IFAL_LABEL, p->label) < 0) {
495		nlmsg_cancel(skb, nlh);
496		return -EMSGSIZE;
497	}
498
499	return nlmsg_end(skb, nlh);
500}
501
502static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
503{
504	struct net *net = sock_net(skb->sk);
505	struct ip6addrlbl_entry *p;
506	struct hlist_node *pos;
507	int idx = 0, s_idx = cb->args[0];
508	int err;
509
510	rcu_read_lock();
511	hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
512		if (idx >= s_idx &&
513		    net_eq(ip6addrlbl_net(p), net)) {
514			if ((err = ip6addrlbl_fill(skb, p,
515						   ip6addrlbl_table.seq,
516						   NETLINK_CB(cb->skb).pid,
517						   cb->nlh->nlmsg_seq,
518						   RTM_NEWADDRLABEL,
519						   NLM_F_MULTI)) <= 0)
520				break;
521		}
522		idx++;
523	}
524	rcu_read_unlock();
525	cb->args[0] = idx;
526	return skb->len;
527}
528
529static inline int ip6addrlbl_msgsize(void)
530{
531	return (NLMSG_ALIGN(sizeof(struct ifaddrlblmsg))
532		+ nla_total_size(16)	/* IFAL_ADDRESS */
533		+ nla_total_size(4)	/* IFAL_LABEL */
534	);
535}
536
537static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr* nlh,
538			  void *arg)
539{
540	struct net *net = sock_net(in_skb->sk);
541	struct ifaddrlblmsg *ifal;
542	struct nlattr *tb[IFAL_MAX+1];
543	struct in6_addr *addr;
544	u32 lseq;
545	int err = 0;
546	struct ip6addrlbl_entry *p;
547	struct sk_buff *skb;
548
549	err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
550	if (err < 0)
551		return err;
552
553	ifal = nlmsg_data(nlh);
554
555	if (ifal->ifal_family != AF_INET6 ||
556	    ifal->ifal_prefixlen != 128)
557		return -EINVAL;
558
559	if (ifal->ifal_index &&
560	    !__dev_get_by_index(net, ifal->ifal_index))
561		return -EINVAL;
562
563	if (!tb[IFAL_ADDRESS])
564		return -EINVAL;
565
566	addr = nla_data(tb[IFAL_ADDRESS]);
567	if (!addr)
568		return -EINVAL;
569
570	rcu_read_lock();
571	p = __ipv6_addr_label(net, addr, ipv6_addr_type(addr), ifal->ifal_index);
572	if (p && ip6addrlbl_hold(p))
573		p = NULL;
574	lseq = ip6addrlbl_table.seq;
575	rcu_read_unlock();
576
577	if (!p) {
578		err = -ESRCH;
579		goto out;
580	}
581
582	if (!(skb = nlmsg_new(ip6addrlbl_msgsize(), GFP_KERNEL))) {
583		ip6addrlbl_put(p);
584		return -ENOBUFS;
585	}
586
587	err = ip6addrlbl_fill(skb, p, lseq,
588			      NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
589			      RTM_NEWADDRLABEL, 0);
590
591	ip6addrlbl_put(p);
592
593	if (err < 0) {
594		WARN_ON(err == -EMSGSIZE);
595		kfree_skb(skb);
596		goto out;
597	}
598
599	err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
600out:
601	return err;
602}
603
604void __init ipv6_addr_label_rtnl_register(void)
605{
606	__rtnl_register(PF_INET6, RTM_NEWADDRLABEL, ip6addrlbl_newdel, NULL);
607	__rtnl_register(PF_INET6, RTM_DELADDRLABEL, ip6addrlbl_newdel, NULL);
608	__rtnl_register(PF_INET6, RTM_GETADDRLABEL, ip6addrlbl_get, ip6addrlbl_dump);
609}
610
611