[PATCH net-next 4/6] xfrm: Convert __xfrm_dst_lookup() to dscp_t.

[Guillaume Nault <gnault@redhat.com>]

Pass a dscp_t variable to __xfrm_dst_lookup(), instead of an int, to
prevent accidental setting of ECN bits in ->flowi4_tos.

Callers of ip_mc_validate_source() to consider are:

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

  * xfrm_dev_state_add() in net/xfrm/xfrm_device.c. This function
    sets the tos parameter to 0, which is already a valid dscp_t value,
    so it doesn't need to be adjusted for the new prototype.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
---
 include/net/xfrm.h     | 3 ++-
 net/xfrm/xfrm_policy.c | 8 ++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index b6bfdc6416c7..18c0a6077ae9 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -19,6 +19,7 @@
 
 #include <net/sock.h>
 #include <net/dst.h>
+#include <net/inet_dscp.h>
 #include <net/ip.h>
 #include <net/route.h>
 #include <net/ipv6.h>
@@ -1764,7 +1765,7 @@ static inline int xfrm_user_policy(struct sock *sk, int optname,
 }
 #endif
 
-struct dst_entry *__xfrm_dst_lookup(struct net *net, int tos, int oif,
+struct dst_entry *__xfrm_dst_lookup(struct net *net, dscp_t dscp, int oif,
 				    const xfrm_address_t *saddr,
 				    const xfrm_address_t *daddr,
 				    int family, u32 mark);
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 6e30b110accf..a1b499cc840c 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -270,7 +270,7 @@ static const struct xfrm_if_cb *xfrm_if_get_cb(void)
 	return rcu_dereference(xfrm_if_cb);
 }
 
-struct dst_entry *__xfrm_dst_lookup(struct net *net, int tos, int oif,
+struct dst_entry *__xfrm_dst_lookup(struct net *net, dscp_t dscp, int oif,
 				    const xfrm_address_t *saddr,
 				    const xfrm_address_t *daddr,
 				    int family, u32 mark)
@@ -282,7 +282,8 @@ struct dst_entry *__xfrm_dst_lookup(struct net *net, int tos, int oif,
 	if (unlikely(afinfo == NULL))
 		return ERR_PTR(-EAFNOSUPPORT);
 
-	dst = afinfo->dst_lookup(net, tos, oif, saddr, daddr, mark);
+	dst = afinfo->dst_lookup(net, inet_dscp_to_dsfield(dscp), oif, saddr,
+				 daddr, mark);
 
 	rcu_read_unlock();
 
@@ -310,8 +311,7 @@ static inline struct dst_entry *xfrm_dst_lookup(struct xfrm_state *x,
 		daddr = x->coaddr;
 	}
 
-	dst = __xfrm_dst_lookup(net, inet_dscp_to_dsfield(dscp), oif, saddr,
-				daddr, family, mark);
+	dst = __xfrm_dst_lookup(net, dscp, oif, saddr, daddr, family, mark);
 
 	if (!IS_ERR(dst)) {
 		if (prev_saddr != saddr)
-- 
2.39.2