[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>

include/linux/if_addrlabel.h

+/*
+ * 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

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)
 };

include/net/addrconf.h

@@ -83,6 +83,14 @@ extern void			addrconf_join_solict(struct net_device *dev,
 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)
  */

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 \

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);