[PATCH net-next v2 5/7] net: ip: make ip_route_input_rcu() return drop reasons

[Menglong Dong]

In this commit, we make ip_route_input_rcu() return drop reasons, which
come from ip_route_input_mc() and ip_route_input_slow().

The only caller of ip_route_input_rcu() is ip_route_input_noref(). We
adjust it by making it return -EINVAL on error and ignore the reasons that
ip_route_input_rcu() returns. In the following patch, we will make
ip_route_input_noref() returns the drop reasons.

Signed-off-by: Menglong Dong <dongml2@xxxxxxxxxxxxxxx>
---
 net/ipv4/route.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 9b3f7bebcd86..56a1ebddde24 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2439,9 +2439,10 @@ out:	return reason;
 }
 
 /* called with rcu_read_lock held */
-static int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
-			      dscp_t dscp, struct net_device *dev,
-			      struct fib_result *res)
+static enum skb_drop_reason
+ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
+		   dscp_t dscp, struct net_device *dev,
+		   struct fib_result *res)
 {
 	/* Multicast recognition logic is moved from route cache to here.
 	 * The problem was that too many Ethernet cards have broken/missing
@@ -2485,23 +2486,23 @@ static int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 						   inet_dscp_to_dsfield(dscp),
 						   dev, our);
 		}
-		return reason ? -EINVAL : 0;
+		return reason;
 	}
 
-	return ip_route_input_slow(skb, daddr, saddr, dscp, dev, res) ? -EINVAL : 0;
+	return ip_route_input_slow(skb, daddr, saddr, dscp, dev, res);
 }
 
 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 			 dscp_t dscp, struct net_device *dev)
 {
+	enum skb_drop_reason reason;
 	struct fib_result res;
-	int err;
 
 	rcu_read_lock();
-	err = ip_route_input_rcu(skb, daddr, saddr, dscp, dev, &res);
+	reason = ip_route_input_rcu(skb, daddr, saddr, dscp, dev, &res);
 	rcu_read_unlock();
 
-	return err;
+	return reason ? -EINVAL : 0;
 }
 EXPORT_SYMBOL(ip_route_input_noref);
 
@@ -3314,6 +3315,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 		err = ip_route_input_rcu(skb, dst, src,
 					 inet_dsfield_to_dscp(rtm->rtm_tos),
 					 dev, &res);
+		err = err ? -EINVAL : 0;
 
 		rt = skb_rtable(skb);
 		if (err == 0 && rt->dst.error)
-- 
2.39.5