Subject: [PATCH RFC net-next 12/20] net/ipv6: Add rt6_info create function for ip6_pol_route_lookup

From: David Ahern <[email-masked]>
Date: Sun, 25 Feb 2018 11:47:22 -0800

ip6_pol_route_lookup is the lookup function for ip6_route_lookup and
rt6_lookup. At the moment it returns either a reference to a FIB entry
or a cached exception. To move FIB entries to a separate struct, this
lookup function need to convert FIB entries to an rt6_info that is
returned to the caller.

Signed-off-by: David Ahern <[email-masked]>
---
 net/ipv6/route.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 31832b170a9f..066203d2f9d3 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1053,6 +1053,20 @@ static bool ip6_hold_safe(struct net *net, struct rt6_info **prt,
 	return false;
 }
 
+/* called with rcu_lock held */
+static struct rt6_info *ip6_create_rt_rcu(struct rt6_info *rt)
+{
+	struct net_device *dev;
+	struct rt6_info *nrt;
+
+	dev = ip6_rt_get_dev_rcu(rt);
+	nrt = __ip6_dst_alloc(dev_net(dev), dev, 0);
+	if (nrt)
+		ip6_rt_copy_init(nrt, rt);
+
+	return nrt;
+}
+
 static struct rt6_info *ip6_pol_route_lookup(struct net *net,
 					     struct fib6_table *table,
 					     struct flowi6 *fl6, int flags)
@@ -1080,18 +1094,19 @@ static struct rt6_info *ip6_pol_route_lookup(struct net *net,
 	}
 	/* Search through exception table */
 	rt_cache = rt6_find_cached_rt(rt, &fl6->daddr, &fl6->saddr);
-	if (rt_cache)
+	if (rt_cache) {
 		rt = rt_cache;
-
-	if (ip6_hold_safe(net, &rt, true))
-		dst_use_noref(&rt->dst, jiffies);
+		if (ip6_hold_safe(net, &rt, true))
+			dst_use_noref(&rt->dst, jiffies);
+	} else {
+		rt = ip6_create_rt_rcu(rt);
+	}
 
 	rcu_read_unlock();
 
 	trace_fib6_table_lookup(net, rt, table, fl6);
 
 	return rt;
-
 }
 
 struct dst_entry *ip6_route_lookup(struct net *net, struct flowi6 *fl6,
-- 
2.11.0