[IPV6] ADDRCONF: Support RFC3484 configurable address selection policy table.

Policy table is implemented as an RCU linear list since we do not expect
large list nor frequent updates.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 608 insertions, 31 deletions

diff --git a/include/linux/if_addrlabel.h b/include/linux/if_addrlabel.h
new file mode 100644
index 000000000000..9fe79c95dd28
--- /dev/null
+++ b/include/linux/if_addrlabel.h
@@ -0,0 +1,32 @@
+/*
+ * if_addrlabel.h - netlink interface for address labels
+ *
+ * Copyright (C)2007 USAGI/WIDE Project,  All Rights Reserved.
+ *
+ * Authors:
+ *      YOSHIFUJI Hideaki @ USAGI/WIDE <yoshfuji@linux-ipv6.org>
+ */
+
+#ifndef __LINUX_IF_ADDRLABEL_H
+#define __LINUX_IF_ADDRLABEL_H
+
+struct ifaddrlblmsg
+{
+        __u8            ifal_family;            /* Address family */
+        __u8            __ifal_reserved;        /* Reserved */
+        __u8            ifal_prefixlen;         /* Prefix length */
+        __u8            ifal_flags;             /* Flags */
+        __u32           ifal_index;             /* Link index */
+        __u32           ifal_seq;               /* sequence number */
+};
+
+enum
+{
+        IFAL_ADDRESS = 1,
+        IFAL_LABEL = 2,
+        __IFAL_MAX
+};
+
+#define IFAL_MAX        (__IFAL_MAX - 1)
+
+#endif
diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index 4e81836191df..e20dcc89a836 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -100,6 +100,13 @@ enum {
         RTM_NEWNDUSEROPT = 68,
 #define RTM_NEWNDUSEROPT RTM_NEWNDUSEROPT
 
+        RTM_NEWADDRLABEL = 72,
+#define RTM_NEWADDRLABEL RTM_NEWADDRLABEL
+        RTM_DELADDRLABEL,
+#define RTM_NEWADDRLABEL RTM_NEWADDRLABEL
+        RTM_GETADDRLABEL,
+#define RTM_GETADDRLABEL RTM_GETADDRLABEL
+
         __RTM_MAX,
 #define RTM_MAX         (((__RTM_MAX + 3) & ~3) - 1)
 };
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 33b593e17441..bccc2feb99da 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -84,6 +84,14 @@ extern void			addrconf_leave_solict(struct inet6_dev *idev,
                                         struct in6_addr *addr);
 
 /*
+ *      IPv6 Address Label subsystem (addrlabel.c)
+ */
+extern int                      ipv6_addr_label_init(void);
+extern void                     ipv6_addr_label_rtnl_register(void);
+extern u32                      ipv6_addr_label(const struct in6_addr *addr,
+                                                int type, int ifindex);
+
+/*
  *      multicast prototypes (mcast.c)
  */
 extern int ipv6_sock_mc_join(struct sock *sk, int ifindex, 
diff --git a/net/ipv6/Makefile b/net/ipv6/Makefile
index 87c23a73d284..5ffa98003058 100644
--- a/net/ipv6/Makefile
+++ b/net/ipv6/Makefile
@@ -5,6 +5,7 @@
 obj-$(CONFIG_IPV6) += ipv6.o
 
 ipv6-objs :=    af_inet6.o anycast.o ip6_output.o ip6_input.o addrconf.o \
+                addrlabel.o \
                 route.o ip6_fib.o ipv6_sockglue.o ndisc.o udp.o udplite.o \
                 raw.o protocol.o icmp.o mcast.o reassembly.o tcp_ipv6.o \
                 exthdrs.o sysctl_net_ipv6.o datagram.o \
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index e1e591bfbdca..a70cecf8fc8d 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -874,36 +874,6 @@ static inline int ipv6_saddr_preferred(int type)
         return 0;
 }
 
-/* static matching label */
-static inline int ipv6_addr_label(const struct in6_addr *addr, int type,
-                                  int ifindex)
-{
- /*
-  *     prefix (longest match)  label
-  *     -----------------------------
-  *     ::1/128                 0
-  *     ::/0                    1
-  *     2002::/16               2
-  *     ::/96                   3
-  *     ::ffff:0:0/96           4
-  *     fc00::/7                5
-  *     2001::/32               6
-  */
-        if (type & IPV6_ADDR_LOOPBACK)
-                return 0;
-        else if (type & IPV6_ADDR_COMPATv4)
-                return 3;
-        else if (type & IPV6_ADDR_MAPPED)
-                return 4;
-        else if (addr->s6_addr32[0] == htonl(0x20010000))
-                return 6;
-        else if (addr->s6_addr16[0] == htons(0x2002))
-                return 2;
-        else if ((addr->s6_addr[0] & 0xfe) == 0xfc)
-                return 5;
-        return 1;
-}
-
 int ipv6_dev_get_saddr(struct net_device *daddr_dev,
                        struct in6_addr *daddr, struct in6_addr *saddr)
 {
@@ -4189,7 +4159,13 @@ EXPORT_SYMBOL(unregister_inet6addr_notifier);
 
 int __init addrconf_init(void)
 {
-        int err = 0;
+        int err;
+
+        if ((err = ipv6_addr_label_init()) < 0) {
+                printk(KERN_CRIT "IPv6 Addrconf: cannot initialize default policy table: %d.\n",
+                        err);
+                return err;
+        }
 
         /* The addrconf netdev notifier requires that loopback_dev
          * has it's ipv6 private information allocated and setup
@@ -4240,6 +4216,8 @@ int __init addrconf_init(void)
         __rtnl_register(PF_INET6, RTM_GETMULTICAST, NULL, inet6_dump_ifmcaddr);
         __rtnl_register(PF_INET6, RTM_GETANYCAST, NULL, inet6_dump_ifacaddr);
 
+        ipv6_addr_label_rtnl_register();
+
 #ifdef CONFIG_SYSCTL
         addrconf_sysctl.sysctl_header =
                 register_sysctl_table(addrconf_sysctl.addrconf_root_dir);
diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
new file mode 100644
index 000000000000..204d4d66834c
--- /dev/null
+++ b/net/ipv6/addrlabel.c
@@ -0,0 +1,551 @@
+/*
+ * IPv6 Address Label subsystem
+ * for the IPv6 "Default" Source Address Selection
+ *
+ * Copyright (C)2007 USAGI/WIDE Project
+ */
+/*
+ * Author:
+ *      YOSHIFUJI Hideaki @ USAGI/WIDE Project <yoshfuji@linux-ipv6.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/rcupdate.h>
+#include <linux/in6.h>
+#include <net/addrconf.h>
+#include <linux/if_addrlabel.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+
+#if 0
+#define ADDRLABEL(x...) printk(x)
+#else
+#define ADDRLABEL(x...) do { ; } while(0)
+#endif
+
+/*
+ * Policy Table
+ */
+struct ip6addrlbl_entry
+{
+        struct in6_addr prefix;
+        int prefixlen;
+        int ifindex;
+        int addrtype;
+        u32 label;
+        struct hlist_node list;
+        atomic_t refcnt;
+        struct rcu_head rcu;
+};
+
+static struct ip6addrlbl_table
+{
+        struct hlist_head head;
+        spinlock_t lock;
+        u32 seq;
+} ip6addrlbl_table;
+
+/*
+ * Default policy table (RFC3484 + extensions)
+ *
+ * prefix               addr_type       label
+ * -------------------------------------------------------------------------
+ * ::1/128              LOOPBACK        0
+ * ::/0                 N/A             1
+ * 2002::/16            N/A             2
+ * ::/96                COMPATv4        3
+ * ::ffff:0:0/96        V4MAPPED        4
+ * fc00::/7             N/A             5               ULA (RFC 4193)
+ * 2001::/32            N/A             6               Teredo (RFC 4380)
+ *
+ * Note: 0xffffffff is used if we do not have any policies.
+ */
+
+#define IPV6_ADDR_LABEL_DEFAULT 0xffffffffUL
+
+static const __initdata struct ip6addrlbl_init_table
+{
+        const struct in6_addr *prefix;
+        int prefixlen;
+        u32 label;
+} ip6addrlbl_init_table[] = {
+        {       /* ::/0 */
+                .prefix = &in6addr_any,
+                .label = 1,
+        },{     /* fc00::/7 */
+                .prefix = &(struct in6_addr){{{ 0xfc }}},
+                .prefixlen = 7,
+                .label = 5,
+        },{     /* 2002::/16 */
+                .prefix = &(struct in6_addr){{{ 0x20, 0x02 }}},
+                .prefixlen = 16,
+                .label = 2,
+        },{     /* 2001::/32 */
+                .prefix = &(struct in6_addr){{{ 0x20, 0x01 }}},
+                .prefixlen = 32,
+                .label = 6,
+        },{     /* ::ffff:0:0 */
+                .prefix = &(struct in6_addr){{{ [10] = 0xff, [11] = 0xff }}},
+                .prefixlen = 96,
+                .label = 4,
+        },{     /* ::/96 */
+                .prefix = &in6addr_any,
+                .prefixlen = 96,
+                .label = 3,
+        },{     /* ::1/128 */
+                .prefix = &in6addr_loopback,
+                .prefixlen = 128,
+                .label = 0,
+        }
+};
+
+/* Object management */
+static inline void ip6addrlbl_free(struct ip6addrlbl_entry *p)
+{
+        kfree(p);
+}
+
+static inline int ip6addrlbl_hold(struct ip6addrlbl_entry *p)
+{
+        return atomic_inc_not_zero(&p->refcnt);
+}
+
+static inline void ip6addrlbl_put(struct ip6addrlbl_entry *p)
+{
+        if (atomic_dec_and_test(&p->refcnt))
+                ip6addrlbl_free(p);
+}
+
+static void ip6addrlbl_free_rcu(struct rcu_head *h)
+{
+        ip6addrlbl_free(container_of(h, struct ip6addrlbl_entry, rcu));
+}
+
+/* Find label */
+static int __ip6addrlbl_match(struct ip6addrlbl_entry *p,
+                              const struct in6_addr *addr,
+                              int addrtype, int ifindex)
+{
+        if (p->ifindex && p->ifindex != ifindex)
+                return 0;
+        if (p->addrtype && p->addrtype != addrtype)
+                return 0;
+        if (!ipv6_prefix_equal(addr, &p->prefix, p->prefixlen))
+                return 0;
+        return 1;
+}
+
+static struct ip6addrlbl_entry *__ipv6_addr_label(const struct in6_addr *addr,
+                                                  int type, int ifindex)
+{
+        struct hlist_node *pos;
+        struct ip6addrlbl_entry *p;
+        hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
+                if (__ip6addrlbl_match(p, addr, type, ifindex))
+                        return p;
+        }
+        return NULL;
+}
+
+u32 ipv6_addr_label(const struct in6_addr *addr, int type, int ifindex)
+{
+        u32 label;
+        struct ip6addrlbl_entry *p;
+
+        type &= IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK;
+
+        rcu_read_lock();
+        p = __ipv6_addr_label(addr, type, ifindex);
+        label = p ? p->label : IPV6_ADDR_LABEL_DEFAULT;
+        rcu_read_unlock();
+
+        ADDRLABEL(KERN_DEBUG "%s(addr=" NIP6_FMT ", type=%d, ifindex=%d) => %08x\n",
+                        __FUNCTION__,
+                        NIP6(*addr), type, ifindex,
+                        label);
+
+        return label;
+}
+
+/* allocate one entry */
+struct ip6addrlbl_entry *ip6addrlbl_alloc(const struct in6_addr *prefix,
+                                          int prefixlen, int ifindex,
+                                          u32 label)
+{
+        struct ip6addrlbl_entry *newp;
+        int addrtype;
+
+        ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d, label=%u)\n",
+                        __FUNCTION__,
+                        NIP6(*prefix), prefixlen,
+                        ifindex,
+                        (unsigned int)label);
+
+        addrtype = ipv6_addr_type(prefix) & (IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK);
+
+        switch (addrtype) {
+        case IPV6_ADDR_MAPPED:
+                if (prefixlen > 96)
+                        return ERR_PTR(-EINVAL);
+                if (prefixlen < 96)
+                        addrtype = 0;
+                break;
+        case IPV6_ADDR_COMPATv4:
+                if (prefixlen != 96)
+                        addrtype = 0;
+                break;
+        case IPV6_ADDR_LOOPBACK:
+                if (prefixlen != 128)
+                        addrtype = 0;
+                break;
+        }
+
+        newp = kmalloc(sizeof(*newp), GFP_KERNEL);
+        if (!newp)
+                return ERR_PTR(-ENOMEM);
+
+        ipv6_addr_prefix(&newp->prefix, prefix, prefixlen);
+        newp->prefixlen = prefixlen;
+        newp->ifindex = ifindex;
+        newp->addrtype = addrtype;
+        newp->label = label;
+        INIT_HLIST_NODE(&newp->list);
+        atomic_set(&newp->refcnt, 1);
+        return newp;
+}
+
+/* add a label */
+int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
+{
+        int ret = 0;
+
+        ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n",
+                        __FUNCTION__,
+                        newp, replace);
+
+        if (hlist_empty(&ip6addrlbl_table.head)) {
+                hlist_add_head_rcu(&newp->list, &ip6addrlbl_table.head);
+        } else {
+                struct hlist_node *pos, *n;
+                struct ip6addrlbl_entry *p = NULL;
+                hlist_for_each_entry_safe(p, pos, n,
+                                          &ip6addrlbl_table.head, list) {
+                        if (p->prefixlen == newp->prefixlen &&
+                            p->ifindex == newp->ifindex &&
+                            ipv6_addr_equal(&p->prefix, &newp->prefix)) {
+                                if (!replace) {
+                                        ret = -EEXIST;
+                                        goto out;
+                                }
+                                hlist_replace_rcu(&p->list, &newp->list);
+                                ip6addrlbl_put(p);
+                                call_rcu(&p->rcu, ip6addrlbl_free_rcu);
+                                goto out;
+                        } else if ((p->prefixlen == newp->prefixlen && !p->ifindex) ||
+                                   (p->prefixlen < newp->prefixlen)) {
+                                hlist_add_before_rcu(&newp->list, &p->list);
+                                goto out;
+                        }
+                }
+                hlist_add_after_rcu(&p->list, &newp->list);
+        }
+out:
+        if (!ret)
+                ip6addrlbl_table.seq++;
+        return ret;
+}
+
+/* add a label */
+int ip6addrlbl_add(const struct in6_addr *prefix, int prefixlen,
+                       int ifindex, u32 label, int replace)
+{
+        struct ip6addrlbl_entry *newp;
+        int ret = 0;
+
+        ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d, label=%u, replace=%d)\n",
+                        __FUNCTION__,
+                        NIP6(*prefix), prefixlen,
+                        ifindex,
+                        (unsigned int)label,
+                        replace);
+
+        newp = ip6addrlbl_alloc(prefix, prefixlen, ifindex, label);
+        if (IS_ERR(newp))
+                return PTR_ERR(newp);
+        spin_lock(&ip6addrlbl_table.lock);
+        ret = __ip6addrlbl_add(newp, replace);
+        spin_unlock(&ip6addrlbl_table.lock);
+        if (ret)
+                ip6addrlbl_free(newp);
+        return ret;
+}
+
+/* remove a label */
+int __ip6addrlbl_del(const struct in6_addr *prefix, int prefixlen,
+                          int ifindex)
+{
+        struct ip6addrlbl_entry *p = NULL;
+        struct hlist_node *pos, *n;
+        int ret = -ESRCH;
+
+        ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d)\n",
+                        __FUNCTION__,
+                        NIP6(*prefix), prefixlen,
+                        ifindex);
+
+        hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
+                if (p->prefixlen == prefixlen &&
+                    p->ifindex == ifindex &&
+                    ipv6_addr_equal(&p->prefix, prefix)) {
+                        hlist_del_rcu(&p->list);
+                        ip6addrlbl_put(p);
+                        call_rcu(&p->rcu, ip6addrlbl_free_rcu);
+                        ret = 0;
+                        break;
+                }
+        }
+        return ret;
+}
+
+int ip6addrlbl_del(const struct in6_addr *prefix, int prefixlen,
+                       int ifindex)
+{
+        struct in6_addr prefix_buf;
+        int ret;
+
+        ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d)\n",
+                        __FUNCTION__,
+                        NIP6(*prefix), prefixlen,
+                        ifindex);
+
+        ipv6_addr_prefix(&prefix_buf, prefix, prefixlen);
+        spin_lock(&ip6addrlbl_table.lock);
+        ret = __ip6addrlbl_del(&prefix_buf, prefixlen, ifindex);
+        spin_unlock(&ip6addrlbl_table.lock);
+        return ret;
+}
+
+/* add default label */
+static __init int ip6addrlbl_init(void)
+{
+        int err = 0;
+        int i;
+
+        ADDRLABEL(KERN_DEBUG "%s()\n", __FUNCTION__);
+
+        for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) {
+                int ret = ip6addrlbl_add(ip6addrlbl_init_table[i].prefix,
+                                         ip6addrlbl_init_table[i].prefixlen,
+                                         0,
+                                         ip6addrlbl_init_table[i].label, 0);
+                /* XXX: should we free all rules when we catch an error? */
+                if (ret && (!err || err != -ENOMEM))
+                        err = ret;
+        }
+        return err;
+}
+
+int __init ipv6_addr_label_init(void)
+{
+        spin_lock_init(&ip6addrlbl_table.lock);
+
+        return ip6addrlbl_init();
+}
+
+static const struct nla_policy ifal_policy[IFAL_MAX+1] = {
+        [IFAL_ADDRESS]          = { .len = sizeof(struct in6_addr), },
+        [IFAL_LABEL]            = { .len = sizeof(u32), },
+};
+
+static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh,
+                             void *arg)
+{
+        struct ifaddrlblmsg *ifal;
+        struct nlattr *tb[IFAL_MAX+1];
+        struct in6_addr *pfx;
+        u32 label;
+        int err = 0;
+
+        err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
+        if (err < 0)
+                return err;
+
+        ifal = nlmsg_data(nlh);
+
+        if (ifal->ifal_family != AF_INET6 ||
+            ifal->ifal_prefixlen > 128)
+                return -EINVAL;
+
+        if (ifal->ifal_index &&
+            !__dev_get_by_index(&init_net, ifal->ifal_index))
+                return -EINVAL;
+
+        if (!tb[IFAL_ADDRESS])
+                return -EINVAL;
+
+        pfx = nla_data(tb[IFAL_ADDRESS]);
+        if (!pfx)
+                return -EINVAL;
+
+        if (!tb[IFAL_LABEL])
+                return -EINVAL;
+        label = nla_get_u32(tb[IFAL_LABEL]);
+        if (label == IPV6_ADDR_LABEL_DEFAULT)
+                return -EINVAL;
+
+        switch(nlh->nlmsg_type) {
+        case RTM_NEWADDRLABEL:
+                err = ip6addrlbl_add(pfx, ifal->ifal_prefixlen,
+                                     ifal->ifal_index, label,
+                                     nlh->nlmsg_flags & NLM_F_REPLACE);
+                break;
+        case RTM_DELADDRLABEL:
+                err = ip6addrlbl_del(pfx, ifal->ifal_prefixlen,
+                                     ifal->ifal_index);
+                break;
+        default:
+                err = -EOPNOTSUPP;
+        }
+        return err;
+}
+
+static inline void ip6addrlbl_putmsg(struct nlmsghdr *nlh,
+                                     int prefixlen, int ifindex, u32 lseq)
+{
+        struct ifaddrlblmsg *ifal = nlmsg_data(nlh);
+        ifal->ifal_family = AF_INET6;
+        ifal->ifal_prefixlen = prefixlen;
+        ifal->ifal_flags = 0;
+        ifal->ifal_index = ifindex;
+        ifal->ifal_seq = lseq;
+};
+
+static int ip6addrlbl_fill(struct sk_buff *skb,
+                           struct ip6addrlbl_entry *p,
+                           u32 lseq,
+                           u32 pid, u32 seq, int event,
+                           unsigned int flags)
+{
+        struct nlmsghdr *nlh = nlmsg_put(skb, pid, seq, event,
+                                         sizeof(struct ifaddrlblmsg), flags);
+        if (!nlh)
+                return -EMSGSIZE;
+
+        ip6addrlbl_putmsg(nlh, p->prefixlen, p->ifindex, lseq);
+
+        if (nla_put(skb, IFAL_ADDRESS, 16, &p->prefix) < 0 ||
+            nla_put_u32(skb, IFAL_LABEL, p->label) < 0) {
+                nlmsg_cancel(skb, nlh);
+                return -EMSGSIZE;
+        }
+
+        return nlmsg_end(skb, nlh);
+}
+
+static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+        struct ip6addrlbl_entry *p;
+        struct hlist_node *pos;
+        int idx = 0, s_idx = cb->args[0];
+        int err;
+
+        rcu_read_lock();
+        hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
+                if (idx >= s_idx) {
+                        if ((err = ip6addrlbl_fill(skb, p,
+                                                   ip6addrlbl_table.seq,
+                                                   NETLINK_CB(cb->skb).pid,
+                                                   cb->nlh->nlmsg_seq,
+                                                   RTM_NEWADDRLABEL,
+                                                   NLM_F_MULTI)) <= 0)
+                                break;
+                }
+                idx++;
+        }
+        rcu_read_unlock();
+        cb->args[0] = idx;
+        return skb->len;
+}
+
+static inline int ip6addrlbl_msgsize(void)
+{
+        return (NLMSG_ALIGN(sizeof(struct ifaddrlblmsg))
+                + nla_total_size(16)    /* IFAL_ADDRESS */
+                + nla_total_size(4)     /* IFAL_LABEL */
+        );
+}
+
+static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr* nlh,
+                          void *arg)
+{
+        struct ifaddrlblmsg *ifal;
+        struct nlattr *tb[IFAL_MAX+1];
+        struct in6_addr *addr;
+        u32 lseq;
+        int err = 0;
+        struct ip6addrlbl_entry *p;
+        struct sk_buff *skb;
+
+        err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
+        if (err < 0)
+                return err;
+
+        ifal = nlmsg_data(nlh);
+
+        if (ifal->ifal_family != AF_INET6 ||
+            ifal->ifal_prefixlen != 128)
+                return -EINVAL;
+
+        if (ifal->ifal_index &&
+            !__dev_get_by_index(&init_net, ifal->ifal_index))
+                return -EINVAL;
+
+        if (!tb[IFAL_ADDRESS])
+                return -EINVAL;
+
+        addr = nla_data(tb[IFAL_ADDRESS]);
+        if (!addr)
+                return -EINVAL;
+
+        rcu_read_lock();
+        p = __ipv6_addr_label(addr, ipv6_addr_type(addr), ifal->ifal_index);
+        if (p && ip6addrlbl_hold(p))
+                p = NULL;
+        lseq = ip6addrlbl_table.seq;
+        rcu_read_unlock();
+
+        if (!p) {
+                err = -ESRCH;
+                goto out;
+        }
+
+        if (!(skb = nlmsg_new(ip6addrlbl_msgsize(), GFP_KERNEL))) {
+                ip6addrlbl_put(p);
+                return -ENOBUFS;
+        }
+
+        err = ip6addrlbl_fill(skb, p, lseq,
+                              NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
+                              RTM_NEWADDRLABEL, 0);
+
+        ip6addrlbl_put(p);
+
+        if (err < 0) {
+                WARN_ON(err == -EMSGSIZE);
+                kfree_skb(skb);
+                goto out;
+        }
+
+        err = rtnl_unicast(skb, NETLINK_CB(in_skb).pid);
+out:
+        return err;
+}
+
+void __init ipv6_addr_label_rtnl_register(void)
+{
+        __rtnl_register(PF_INET6, RTM_NEWADDRLABEL, ip6addrlbl_newdel, NULL);
+        __rtnl_register(PF_INET6, RTM_DELADDRLABEL, ip6addrlbl_newdel, NULL);
+        __rtnl_register(PF_INET6, RTM_GETADDRLABEL, ip6addrlbl_get, ip6addrlbl_dump);
+}
+