[RFC 2/2] [IPV6] ADDRCONF: Support RFC3484 configurable address selection policy table.

[RFC 2/2] [IPV6] ADDRCONF: Support RFC3484 configurable address selection policy table.

[YOSHIFUJI Hideaki / 吉藤英明]

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
---
 include/linux/if_addrlabel.h |   55 ++++
 include/linux/rtnetlink.h    |    7 +
 include/net/addrconf.h       |    8 +
 net/ipv6/Makefile            |    1 +
 net/ipv6/addrconf.c          |   40 +---
 net/ipv6/addrlabel.c         |  566 ++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 646 insertions(+), 31 deletions(-)

diff --git a/include/linux/if_addrlabel.h b/include/linux/if_addrlabel.h
new file mode 100644
index 0000000..66978a5
--- /dev/null
+++ b/include/linux/if_addrlabel.h
@@ -0,0 +1,55 @@
+/*
+ * ifaddrlabel.h - netlink interface for address labels
+ *
+ * Copyright (C)2007 USAGI/WIDE Project,  All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+#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 5bf6182..9a8bf01 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 33b593e..bccc2fe 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 87c23a7..5ffa980 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 8b408b7..5b6553f 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -876,36 +876,6 @@ 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)
 {
@@ -4182,7 +4152,13 @@ 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
@@ -4233,6 +4209,8 @@ 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 0000000..719e785
--- /dev/null
+++ b/net/ipv6/addrlabel.c
@@ -0,0 +1,566 @@
+/*
+ * IPv6 Address Label subsystem
+ * for the IPv6 "Default" Source Address Selection
+ *
+ * Copyright (C)2007 USAGI/WIDE Project
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+/*
+ * 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 addrlabel_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);
+}
+
-- 
1.4.4.4

Re: [RFC 2/2] [IPV6] ADDRCONF: Support RFC3484 configurable address selection policy table.

[David Miller]

From: YOSHIFUJI Hideaki / 吉藤英明 <yoshfuji@linux-ipv6.org>
Date: Tue, 30 Oct 2007 14:52:54 +0900 (JST)

> diff --git a/include/linux/if_addrlabel.h b/include/linux/if_addrlabel.h
> new file mode 100644
> index 0000000..66978a5
> --- /dev/null
> +++ b/include/linux/if_addrlabel.h
> @@ -0,0 +1,55 @@
> +/*
> + * ifaddrlabel.h - netlink interface for address labels
> + *
> + * Copyright (C)2007 USAGI/WIDE Project,  All Rights Reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:

Please, this is just a very primitive header file definiting a
simplistic struct and a few enumerations.  Can't you just GPL it with
just the USAGI/WIDE copyright line, instead of using this complicated
license text?

If it important for the USAGI Project to take credit for this work,
they will receive it fully in the copyright line and the changelog
entry.

Thank you.

Re: [RFC 2/2] [IPV6] ADDRCONF: Support RFC3484 configurable address selection policy table.

[Paul E. McKenney]

On Tue, Oct 30, 2007 at 02:52:54PM +0900, YOSHIFUJI Hideaki / 吉藤英明 wrote:

Looks good from an RCU perspective.  A couple questions below about
hlist_for_each_entry_safe().

							Thanx, Paul

> Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
> ---
>  include/linux/if_addrlabel.h |   55 ++++
>  include/linux/rtnetlink.h    |    7 +
>  include/net/addrconf.h       |    8 +
>  net/ipv6/Makefile            |    1 +
>  net/ipv6/addrconf.c          |   40 +---
>  net/ipv6/addrlabel.c         |  566 ++++++++++++++++++++++++++++++++++++++++++
>  6 files changed, 646 insertions(+), 31 deletions(-)
> 
> diff --git a/include/linux/if_addrlabel.h b/include/linux/if_addrlabel.h
> new file mode 100644
> index 0000000..66978a5
> --- /dev/null
> +++ b/include/linux/if_addrlabel.h
> @@ -0,0 +1,55 @@
> +/*
> + * ifaddrlabel.h - netlink interface for address labels
> + *
> + * Copyright (C)2007 USAGI/WIDE Project,  All Rights Reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + *
> + * 1. Redistributions of source code must retain the above copyright
> + *    notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + *    notice, this list of conditions and the following disclaimer in the
> + *    documentation and/or other materials provided with the distribution.
> + * 3. Neither the name of the project nor the names of its contributors
> + *    may be used to endorse or promote products derived from this software
> + *    without specific prior written permission.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
> + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + *
> + */
> +
> +#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 5bf6182..9a8bf01 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 33b593e..bccc2fe 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 87c23a7..5ffa980 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 8b408b7..5b6553f 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -876,36 +876,6 @@ 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)
>  {
> @@ -4182,7 +4152,13 @@ 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
> @@ -4233,6 +4209,8 @@ 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 0000000..719e785
> --- /dev/null
> +++ b/net/ipv6/addrlabel.c
> @@ -0,0 +1,566 @@
> +/*
> + * IPv6 Address Label subsystem
> + * for the IPv6 "Default" Source Address Selection
> + *
> + * Copyright (C)2007 USAGI/WIDE Project
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> + *
> + */
> +/*
> + * 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,

Why not list_for_each_entry(), given that you exit the look when you
do the replacement below?

> +					  &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);

Side note:  if you didn't have a "goto out" here, then this would
be vulnerable to the following sequence of events in a CONFIG_PREEMPT_RT
kernel:

1.	Preemption occurs here (cannot happen in CONFIG_PREEMPT or
	vanilla kernel, but can happen in -rt).

2.	Grace period completes.

3.	ip6addrlbl_free_rcu() frees up the current element.

4.	This element is allocated and used for some entirely different
	structure.

5.	This task resumes execution, and the hlist_for_each_entry_safe()
	uses a pointer to the newly repurposed block of memory.  Oops!

> +				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) {

Again, why not list_for_each_entry(), given that you exit the look when
you do the replacement below?

> +		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 addrlabel_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);
> +}
> +
> -- 
> 1.4.4.4
> 
> -
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html