[PATCH net-next 1/7] ipv4: Convert ip_route_use_hint() to dscp_t.

[Guillaume Nault <gnault@redhat.com>]

Pass a dscp_t variable to ip_route_use_hint(), instead of a plain u8,
to prevent accidental setting of ECN bits in ->flowi4_tos.

Only ip_rcv_finish_core() actually calls ip_route_use_hint(). Use the
ip4h_dscp() helper to get the DSCP from the IPv4 header.

While there, modify the declaration of ip_route_use_hint() in
include/net/route.h so that it matches the prototype of its
implementation in net/ipv4/route.c.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
---
 include/net/route.h | 4 ++--
 net/ipv4/ip_input.c | 4 ++--
 net/ipv4/route.c    | 6 +++---
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/net/route.h b/include/net/route.h
index 5e4374d66927..c219c0fecdcf 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -203,8 +203,8 @@ int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 			  struct in_device *in_dev, u32 *itag);
 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 			 dscp_t dscp, struct net_device *dev);
-int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src,
-		      u8 tos, struct net_device *devin,
+int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
+		      dscp_t dscp, struct net_device *dev,
 		      const struct sk_buff *hint);
 
 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index c0a2490eb7c1..89bb63da6852 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -325,8 +325,8 @@ static int ip_rcv_finish_core(struct net *net, struct sock *sk,
 	drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
 
 	if (ip_can_use_hint(skb, iph, hint)) {
-		err = ip_route_use_hint(skb, iph->daddr, iph->saddr, iph->tos,
-					dev, hint);
+		err = ip_route_use_hint(skb, iph->daddr, iph->saddr,
+					ip4h_dscp(iph), dev, hint);
 		if (unlikely(err))
 			goto drop_error;
 	}
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 6e1cd0065b87..ac03916cfcde 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2136,7 +2136,7 @@ static int ip_mkroute_input(struct sk_buff *skb,
  * Uses the provided hint instead of performing a route lookup.
  */
 int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
-		      u8 tos, struct net_device *dev,
+		      dscp_t dscp, struct net_device *dev,
 		      const struct sk_buff *hint)
 {
 	struct in_device *in_dev = __in_dev_get_rcu(dev);
@@ -2160,8 +2160,8 @@ int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	if (rt->rt_type != RTN_LOCAL)
 		goto skip_validate_source;
 
-	tos &= INET_DSCP_MASK;
-	err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag);
+	err = fib_validate_source(skb, saddr, daddr, inet_dscp_to_dsfield(dscp),
+				  0, dev, in_dev, &tag);
 	if (err < 0)
 		goto martian_source;
 
-- 
2.39.2