[NETNS][IPV6] rt6_info - make rt6_info accessed as a pointer

This patch make mindless changes and prepares the code to use dynamic
allocation for rt6_info structure. The code accesses the rt6_info
structure as a pointer instead of a global static variable.

Signed-off-by: Daniel Lezcano <[e-mail]>
Signed-off-by: Benjamin Thery <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/ip6_route.h

···
 #define RT6_LOOKUP_F_REACHABLE	0x2
 #define RT6_LOOKUP_F_HAS_SADDR	0x4
 
-extern struct rt6_info	ip6_null_entry;
+extern struct rt6_info	*ip6_null_entry;
 
 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
-extern struct rt6_info	ip6_prohibit_entry;
-extern struct rt6_info	ip6_blk_hole_entry;
+extern struct rt6_info	*ip6_prohibit_entry;
+extern struct rt6_info	*ip6_blk_hole_entry;
 #endif
 
 extern void			ip6_route_input(struct sk_buff *skb);

net/ipv6/addrconf.c

···
 	if (err)
 		goto errlo;
 
-	ip6_null_entry.u.dst.dev = init_net.loopback_dev;
-	ip6_null_entry.rt6i_idev = in6_dev_get(init_net.loopback_dev);
+	ip6_null_entry->u.dst.dev = init_net.loopback_dev;
+	ip6_null_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
-	ip6_prohibit_entry.u.dst.dev = init_net.loopback_dev;
-	ip6_prohibit_entry.rt6i_idev = in6_dev_get(init_net.loopback_dev);
-	ip6_blk_hole_entry.u.dst.dev = init_net.loopback_dev;
-	ip6_blk_hole_entry.rt6i_idev = in6_dev_get(init_net.loopback_dev);
+	ip6_prohibit_entry->u.dst.dev = init_net.loopback_dev;
+	ip6_prohibit_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
+	ip6_blk_hole_entry->u.dst.dev = init_net.loopback_dev;
+	ip6_blk_hole_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
 #endif
 
 	register_netdevice_notifier(&ipv6_dev_notf);

net/ipv6/fib6_rules.c

···
 	if (arg.result)
 		return arg.result;
 
-	dst_hold(&ip6_null_entry.u.dst);
-	return &ip6_null_entry.u.dst;
+	dst_hold(&ip6_null_entry->u.dst);
+	return &ip6_null_entry->u.dst;
 }
 
 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
···
 	case FR_ACT_TO_TBL:
 		break;
 	case FR_ACT_UNREACHABLE:
-		rt = &ip6_null_entry;
+		rt = ip6_null_entry;
 		goto discard_pkt;
 	default:
 	case FR_ACT_BLACKHOLE:
-		rt = &ip6_blk_hole_entry;
+		rt = ip6_blk_hole_entry;
 		goto discard_pkt;
 	case FR_ACT_PROHIBIT:
-		rt = &ip6_prohibit_entry;
+		rt = ip6_prohibit_entry;
 		goto discard_pkt;
 	}
 
···
 	if (table)
 		rt = lookup(table, flp, flags);
 
-	if (rt != &ip6_null_entry) {
+	if (rt != ip6_null_entry) {
 		struct fib6_rule *r = (struct fib6_rule *)rule;
 
 		/*

net/ipv6/ip6_fib.c

···
 	table = kzalloc(sizeof(*table), GFP_ATOMIC);
 	if (table != NULL) {
 		table->tb6_id = id;
-		table->tb6_root.leaf = &ip6_null_entry;
+		table->tb6_root.leaf = ip6_null_entry;
 		table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 	}
 
···
 			if (sfn == NULL)
 				goto st_failure;
 
-			sfn->leaf = &ip6_null_entry;
-			atomic_inc(&ip6_null_entry.rt6i_ref);
+			sfn->leaf = ip6_null_entry;
+			atomic_inc(&ip6_null_entry->rt6i_ref);
 			sfn->fn_flags = RTN_ROOT;
 			sfn->fn_sernum = fib6_new_sernum();
 
···
 #if RT6_DEBUG >= 2
 			if (!pn->leaf) {
 				BUG_TRAP(pn->leaf != NULL);
-				pn->leaf = &ip6_null_entry;
+				pn->leaf = ip6_null_entry;
 			}
 #endif
 			atomic_inc(&pn->leaf->rt6i_ref);
···
 static struct rt6_info * fib6_find_prefix(struct fib6_node *fn)
 {
 	if (fn->fn_flags&RTN_ROOT)
-		return &ip6_null_entry;
+		return ip6_null_entry;
 
 	while(fn) {
 		if(fn->left)
···
 #if RT6_DEBUG >= 2
 			if (fn->leaf==NULL) {
 				BUG_TRAP(fn->leaf);
-				fn->leaf = &ip6_null_entry;
+				fn->leaf = ip6_null_entry;
 			}
 #endif
 			atomic_inc(&fn->leaf->rt6i_ref);
···
 		return -ENOENT;
 	}
 #endif
-	if (fn == NULL || rt == &ip6_null_entry)
+	if (fn == NULL || rt == ip6_null_entry)
 		return -ENOENT;
 
 	BUG_TRAP(fn->fn_flags&RTN_RTINFO);
···
 		goto out_fib_table_hash;
 
 	net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
-	net->ipv6.fib6_main_tbl->tb6_root.leaf = &ip6_null_entry;
+	net->ipv6.fib6_main_tbl->tb6_root.leaf = ip6_null_entry;
 	net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
 		RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 
···
 	if (!net->ipv6.fib6_local_tbl)
 		goto out_fib6_main_tbl;
 	net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
-	net->ipv6.fib6_local_tbl->tb6_root.leaf = &ip6_null_entry;
+	net->ipv6.fib6_local_tbl->tb6_root.leaf = ip6_null_entry;
 	net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
 		RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 #endif

net/ipv6/route.c

···
 	.entries		=	ATOMIC_INIT(0),
 };
 
-struct rt6_info ip6_null_entry = {
+static struct rt6_info ip6_null_entry_template = {
 	.u = {
 		.dst = {
 			.__refcnt	= ATOMIC_INIT(1),
···
 			.input		= ip6_pkt_discard,
 			.output		= ip6_pkt_discard_out,
 			.ops		= &ip6_dst_ops,
-			.path		= (struct dst_entry*)&ip6_null_entry,
 		}
 	},
 	.rt6i_flags	= (RTF_REJECT | RTF_NONEXTHOP),
···
 	.rt6i_ref	= ATOMIC_INIT(1),
 };
 
+struct rt6_info *ip6_null_entry;
+
 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 
 static int ip6_pkt_prohibit(struct sk_buff *skb);
 static int ip6_pkt_prohibit_out(struct sk_buff *skb);
 
-struct rt6_info ip6_prohibit_entry = {
+struct rt6_info ip6_prohibit_entry_template = {
 	.u = {
 		.dst = {
 			.__refcnt	= ATOMIC_INIT(1),
···
 			.input		= ip6_pkt_prohibit,
 			.output		= ip6_pkt_prohibit_out,
 			.ops		= &ip6_dst_ops,
-			.path		= (struct dst_entry*)&ip6_prohibit_entry,
 		}
 	},
 	.rt6i_flags	= (RTF_REJECT | RTF_NONEXTHOP),
···
 	.rt6i_ref	= ATOMIC_INIT(1),
 };
 
-struct rt6_info ip6_blk_hole_entry = {
+struct rt6_info *ip6_prohibit_entry;
+
+static struct rt6_info ip6_blk_hole_entry_template = {
 	.u = {
 		.dst = {
 			.__refcnt	= ATOMIC_INIT(1),
···
 			.input		= dst_discard,
 			.output		= dst_discard,
 			.ops		= &ip6_dst_ops,
-			.path		= (struct dst_entry*)&ip6_blk_hole_entry,
 		}
 	},
 	.rt6i_flags	= (RTF_REJECT | RTF_NONEXTHOP),
 	.rt6i_metric	= ~(u32) 0,
 	.rt6i_ref	= ATOMIC_INIT(1),
 };
+
+struct rt6_info *ip6_blk_hole_entry;
 
 #endif
 
···
 			return local;
 
 		if (strict)
-			return &ip6_null_entry;
+			return ip6_null_entry;
 	}
 	return rt;
 }
···
 	RT6_TRACE("%s() => %p\n",
 		  __FUNCTION__, match);
 
-	return (match ? match : &ip6_null_entry);
+	return (match ? match : ip6_null_entry);
 }
 
 #ifdef CONFIG_IPV6_ROUTE_INFO
···
 
 #define BACKTRACK(saddr) \
 do { \
-	if (rt == &ip6_null_entry) { \
+	if (rt == ip6_null_entry) { \
 		struct fib6_node *pn; \
 		while (1) { \
 			if (fn->fn_flags & RTN_TL_ROOT) \
···
 restart:
 	rt = rt6_select(fn, oif, strict | reachable);
 	BACKTRACK(&fl->fl6_src);
-	if (rt == &ip6_null_entry ||
+	if (rt == ip6_null_entry ||
 	    rt->rt6i_flags & RTF_CACHE)
 		goto out;
 
···
 	}
 
 	dst_release(&rt->u.dst);
-	rt = nrt ? : &ip6_null_entry;
+	rt = nrt ? : ip6_null_entry;
 
 	dst_hold(&rt->u.dst);
 	if (nrt) {
···
 	int err;
 	struct fib6_table *table;
 
-	if (rt == &ip6_null_entry)
+	if (rt == ip6_null_entry)
 		return -ENOENT;
 
 	table = rt->rt6i_table;
···
 	}
 
 	if (!rt)
-		rt = &ip6_null_entry;
+		rt = ip6_null_entry;
 	BACKTRACK(&fl->fl6_src);
 out:
 	dst_hold(&rt->u.dst);
···
 
 	rt = ip6_route_redirect(dest, src, saddr, neigh->dev);
 
-	if (rt == &ip6_null_entry) {
+	if (rt == ip6_null_entry) {
 		if (net_ratelimit())
 			printk(KERN_DEBUG "rt6_redirect: source isn't a valid nexthop "
 			       "for redirect target\n");
···
 static int fib6_ifdown(struct rt6_info *rt, void *arg)
 {
 	if (((void*)rt->rt6i_dev == arg || arg == NULL) &&
-	    rt != &ip6_null_entry) {
+	    rt != ip6_null_entry) {
 		RT6_TRACE("deleted by ifdown %p\n", rt);
 		return -1;
 	}
···
 
 	ip6_dst_blackhole_ops.kmem_cachep = ip6_dst_ops.kmem_cachep;
 
+	ret = -ENOMEM;
+	ip6_null_entry = kmemdup(&ip6_null_entry_template,
+				 sizeof(*ip6_null_entry), GFP_KERNEL);
+	if (!ip6_null_entry)
+		goto out_kmem_cache;
+	ip6_null_entry->u.dst.path = (struct dst_entry *)ip6_null_entry;
+
+#ifdef CONFIG_IPV6_MULTIPLE_TABLES
+	ip6_prohibit_entry = kmemdup(&ip6_prohibit_entry_template,
+				     sizeof(*ip6_prohibit_entry), GFP_KERNEL);
+	if (!ip6_prohibit_entry)
+		goto out_ip6_null_entry;
+	ip6_prohibit_entry->u.dst.path = (struct dst_entry *)ip6_prohibit_entry;
+
+	ip6_blk_hole_entry = kmemdup(&ip6_blk_hole_entry_template,
+				     sizeof(*ip6_blk_hole_entry), GFP_KERNEL);
+	if (!ip6_blk_hole_entry)
+		goto out_ip6_prohibit_entry;
+	ip6_blk_hole_entry->u.dst.path = (struct dst_entry *)ip6_blk_hole_entry;
+#endif
+
 	ret = fib6_init();
 	if (ret)
-		goto out_kmem_cache;
+		goto out_ip6_blk_hole_entry;
 
 	ret = xfrm6_init();
 	if (ret)
···
 	xfrm6_fini();
 out_fib6_init:
 	fib6_gc_cleanup();
+out_ip6_blk_hole_entry:
+#ifdef CONFIG_IPV6_MULTIPLE_TABLES
+	kfree(ip6_blk_hole_entry);
+out_ip6_prohibit_entry:
+	kfree(ip6_prohibit_entry);
+out_ip6_null_entry:
+#endif
+	kfree(ip6_null_entry);
 out_kmem_cache:
 	kmem_cache_destroy(ip6_dst_ops.kmem_cachep);
 	goto out;
···
 	xfrm6_fini();
 	fib6_gc_cleanup();
 	kmem_cache_destroy(ip6_dst_ops.kmem_cachep);
+
+	kfree(ip6_null_entry);
+#ifdef CONFIG_IPV6_MULTIPLE_TABLES
+	kfree(ip6_prohibit_entry);
+	kfree(ip6_blk_hole_entry);
+#endif
 }