ipv6 netns: Address labels per namespace

This pacth makes IPv6 address labels per network namespace.
It keeps the global label tables, ip6addrlbl_table, but
adds a 'net' member to each ip6addrlbl_entry.
This new member is taken into account when matching labels.

Changelog
=========
* v1: Initial version
* v2:
  * Minize the penalty when network namespaces are not configured:
      *  the 'net' member is added only if CONFIG_NET_NS is
         defined. This saves space when network namespaces are not
         configured.
      * 'net' value is retrieved with the inlined function
         ip6addrlbl_net() that always return &init_net when
         CONFIG_NET_NS is not defined.
  * 'net' member in ip6addrlbl_entry renamed to the less generic
    'lbl_net' name (helps code search).

Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 9ea4e62..fa43374 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -964,7 +964,8 @@
 	return 0;
 }
 
-static int ipv6_get_saddr_eval(struct ipv6_saddr_score *score,
+static int ipv6_get_saddr_eval(struct net *net,
+			       struct ipv6_saddr_score *score,
 			       struct ipv6_saddr_dst *dst,
 			       int i)
 {
@@ -1043,7 +1044,8 @@
 		break;
 	case IPV6_SADDR_RULE_LABEL:
 		/* Rule 6: Prefer matching label */
-		ret = ipv6_addr_label(&score->ifa->addr, score->addr_type,
+		ret = ipv6_addr_label(net,
+				      &score->ifa->addr, score->addr_type,
 				      score->ifa->idev->dev->ifindex) == dst->label;
 		break;
 #ifdef CONFIG_IPV6_PRIVACY
@@ -1097,7 +1099,7 @@
 	dst.addr = daddr;
 	dst.ifindex = dst_dev ? dst_dev->ifindex : 0;
 	dst.scope = __ipv6_addr_src_scope(dst_type);
-	dst.label = ipv6_addr_label(daddr, dst_type, dst.ifindex);
+	dst.label = ipv6_addr_label(net, daddr, dst_type, dst.ifindex);
 	dst.prefs = prefs;
 
 	hiscore->rule = -1;
@@ -1165,8 +1167,8 @@
 			for (i = 0; i < IPV6_SADDR_RULE_MAX; i++) {
 				int minihiscore, miniscore;
 
-				minihiscore = ipv6_get_saddr_eval(hiscore, &dst, i);
-				miniscore = ipv6_get_saddr_eval(score, &dst, i);
+				minihiscore = ipv6_get_saddr_eval(net, hiscore, &dst, i);
+				miniscore = ipv6_get_saddr_eval(net, score, &dst, i);
 
 				if (minihiscore > miniscore) {
 					if (i == IPV6_SADDR_RULE_SCOPE &&