[PATCH net-next 5/7] ipv4: Convert ip_mc_validate_source() to dscp_t.

[Guillaume Nault <gnault@redhat.com>]

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

Callers of ip_mc_validate_source() to consider are:

  * ip_route_input_mc() which already has a dscp_t variable to pass as
    parameter. We just need to remove the inet_dscp_to_dsfield()
    conversion.

  * udp_v4_early_demux() which gets the DSCP directly from the IPv4
    header and can simply use the ip4h_dscp() helper.

Also, stop including net/inet_dscp.h in udp.c as we don't use any of
its declarations anymore.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
---
 include/net/route.h | 3 ++-
 net/ipv4/route.c    | 8 ++++----
 net/ipv4/udp.c      | 4 ++--
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/include/net/route.h b/include/net/route.h
index c219c0fecdcf..586e59f7ed8a 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -198,8 +198,9 @@ static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4
 	fl4->fl4_gre_key = gre_key;
 	return ip_route_output_key(net, fl4);
 }
+
 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
-			  u8 tos, struct net_device *dev,
+			  dscp_t dscp, struct net_device *dev,
 			  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);
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 527121be1ba2..1efb65e647c1 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1666,7 +1666,7 @@ EXPORT_SYMBOL(rt_dst_clone);
 
 /* called in rcu_read_lock() section */
 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
-			  u8 tos, struct net_device *dev,
+			  dscp_t dscp, struct net_device *dev,
 			  struct in_device *in_dev, u32 *itag)
 {
 	int err;
@@ -1687,7 +1687,8 @@ int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 		    ip_hdr(skb)->protocol != IPPROTO_IGMP)
 			return -EINVAL;
 	} else {
-		err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
+		err = fib_validate_source(skb, saddr, 0,
+					  inet_dscp_to_dsfield(dscp), 0, dev,
 					  in_dev, itag);
 		if (err < 0)
 			return err;
@@ -1705,8 +1706,7 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	u32 itag = 0;
 	int err;
 
-	err = ip_mc_validate_source(skb, daddr, saddr,
-				    inet_dscp_to_dsfield(dscp), dev, in_dev,
+	err = ip_mc_validate_source(skb, daddr, saddr, dscp, dev, in_dev,
 				    &itag);
 	if (err)
 		return err;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 8accbf4cb295..4b74a25d0b6e 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -100,6 +100,7 @@
 #include <net/net_namespace.h>
 #include <net/icmp.h>
 #include <net/inet_hashtables.h>
+#include <net/ip.h>
 #include <net/ip_tunnels.h>
 #include <net/route.h>
 #include <net/checksum.h>
@@ -115,7 +116,6 @@
 #include <net/addrconf.h>
 #include <net/udp_tunnel.h>
 #include <net/gro.h>
-#include <net/inet_dscp.h>
 #if IS_ENABLED(CONFIG_IPV6)
 #include <net/ipv6_stubs.h>
 #endif
@@ -2619,7 +2619,7 @@ int udp_v4_early_demux(struct sk_buff *skb)
 		if (!inet_sk(sk)->inet_daddr && in_dev)
 			return ip_mc_validate_source(skb, iph->daddr,
 						     iph->saddr,
-						     iph->tos & INET_DSCP_MASK,
+						     ip4h_dscp(iph),
 						     skb->dev, in_dev, &itag);
 	}
 	return 0;
-- 
2.39.2