ipv4: Use dscp_t in struct fib_rt_info

Use the new dscp_t type to replace the tos field of struct fib_rt_info.
This ensures ECN bits are ignored and makes it compatible with the
fa_dscp field of struct fib_alias.

This also allows sparse to flag potential incorrect uses of DSCP and
ECN bits.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/marvell/prestera/prestera_router.c

@@ -4,6 +4,7 @@
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/inetdevice.h>
+#include <net/inet_dscp.h>
 #include <net/switchdev.h>
 #include <linux/rhashtable.h>
 
@@ -132,7 +133,7 @@ __prestera_k_arb_fib_lpm_offload_set(struct prestera_switch *sw,
 	fri.tb_id = fc->key.kern_tb_id;
 	fri.dst = fc->key.addr.u.ipv4;
 	fri.dst_len = fc->key.prefix_len;
-	fri.tos = fc->kern_tos;
+	fri.dscp = inet_dsfield_to_dscp(fc->kern_tos);
 	fri.type = fc->kern_type;
 	/* flags begin */
 	fri.offload = offload;

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -21,6 +21,7 @@
 #include <net/netevent.h>
 #include <net/neighbour.h>
 #include <net/arp.h>
+#include <net/inet_dscp.h>
 #include <net/ip_fib.h>
 #include <net/ip6_fib.h>
 #include <net/nexthop.h>
@@ -5620,7 +5621,7 @@ mlxsw_sp_fib4_offload_failed_flag_set(struct mlxsw_sp *mlxsw_sp,
 	fri.tb_id = fen_info->tb_id;
 	fri.dst = cpu_to_be32(*p_dst);
 	fri.dst_len = fen_info->dst_len;
-	fri.tos = fen_info->tos;
+	fri.dscp = inet_dsfield_to_dscp(fen_info->tos);
 	fri.type = fen_info->type;
 	fri.offload = false;
 	fri.trap = false;
@@ -5645,7 +5646,7 @@ mlxsw_sp_fib4_entry_hw_flags_set(struct mlxsw_sp *mlxsw_sp,
 	fri.tb_id = fib4_entry->tb_id;
 	fri.dst = cpu_to_be32(*p_dst);
 	fri.dst_len = dst_len;
-	fri.tos = fib4_entry->tos;
+	fri.dscp = inet_dsfield_to_dscp(fib4_entry->tos);
 	fri.type = fib4_entry->type;
 	fri.offload = should_offload;
 	fri.trap = !should_offload;
@@ -5668,7 +5669,7 @@ mlxsw_sp_fib4_entry_hw_flags_clear(struct mlxsw_sp *mlxsw_sp,
 	fri.tb_id = fib4_entry->tb_id;
 	fri.dst = cpu_to_be32(*p_dst);
 	fri.dst_len = dst_len;
-	fri.tos = fib4_entry->tos;
+	fri.dscp = inet_dsfield_to_dscp(fib4_entry->tos);
 	fri.type = fib4_entry->type;
 	fri.offload = false;
 	fri.trap = false;

drivers/net/netdevsim/fib.c

@@ -22,6 +22,7 @@
 #include <linux/spinlock_types.h>
 #include <linux/types.h>
 #include <net/fib_notifier.h>
+#include <net/inet_dscp.h>
 #include <net/ip_fib.h>
 #include <net/ip6_fib.h>
 #include <net/fib_rules.h>
@@ -322,7 +323,7 @@ nsim_fib4_rt_offload_failed_flag_set(struct net *net,
 	fri.tb_id = fen_info->tb_id;
 	fri.dst = cpu_to_be32(*p_dst);
 	fri.dst_len = fen_info->dst_len;
-	fri.tos = fen_info->tos;
+	fri.dscp = inet_dsfield_to_dscp(fen_info->tos);
 	fri.type = fen_info->type;
 	fri.offload = false;
 	fri.trap = false;
@@ -342,7 +343,7 @@ static void nsim_fib4_rt_hw_flags_set(struct net *net,
 	fri.tb_id = fib4_rt->common.key.tb_id;
 	fri.dst = cpu_to_be32(*p_dst);
 	fri.dst_len = dst_len;
-	fri.tos = fib4_rt->tos;
+	fri.dscp = inet_dsfield_to_dscp(fib4_rt->tos);
 	fri.type = fib4_rt->type;
 	fri.offload = false;
 	fri.trap = trap;

include/net/ip_fib.h

@@ -212,7 +212,7 @@ struct fib_rt_info {
 	u32			tb_id;
 	__be32			dst;
 	int			dst_len;
-	u8			tos;
+	dscp_t			dscp;
 	u8			type;
 	u8			offload:1,
 				trap:1,

net/ipv4/fib_semantics.c

@@ -524,7 +524,7 @@ void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
 	fri.tb_id = tb_id;
 	fri.dst = key;
 	fri.dst_len = dst_len;
-	fri.tos = inet_dscp_to_dsfield(fa->fa_dscp);
+	fri.dscp = fa->fa_dscp;
 	fri.type = fa->fa_type;
 	fri.offload = READ_ONCE(fa->offload);
 	fri.trap = READ_ONCE(fa->trap);
@@ -1781,7 +1781,7 @@ int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
 	rtm->rtm_family = AF_INET;
 	rtm->rtm_dst_len = fri->dst_len;
 	rtm->rtm_src_len = 0;
-	rtm->rtm_tos = fri->tos;
+	rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp);
 	if (tb_id < 256)
 		rtm->rtm_table = tb_id;
 	else

net/ipv4/fib_trie.c

@@ -1032,8 +1032,8 @@ fib_find_matching_alias(struct net *net, const struct fib_rt_info *fri)
 
 	hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
 		if (fa->fa_slen == slen && fa->tb_id == fri->tb_id &&
-		    fa->fa_dscp == inet_dsfield_to_dscp(fri->tos) &&
-		    fa->fa_info == fri->fi && fa->fa_type == fri->type)
+		    fa->fa_dscp == fri->dscp && fa->fa_info == fri->fi &&
+		    fa->fa_type == fri->type)
 			return fa;
 	}
 
@@ -2305,7 +2305,7 @@ static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
 				fri.tb_id = tb->tb_id;
 				fri.dst = xkey;
 				fri.dst_len = KEYLENGTH - fa->fa_slen;
-				fri.tos = inet_dscp_to_dsfield(fa->fa_dscp);
+				fri.dscp = fa->fa_dscp;
 				fri.type = fa->fa_type;
 				fri.offload = READ_ONCE(fa->offload);
 				fri.trap = READ_ONCE(fa->trap);

net/ipv4/route.c

@@ -3394,7 +3394,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 		fri.tb_id = table_id;
 		fri.dst = res.prefix;
 		fri.dst_len = res.prefixlen;
-		fri.tos = fl4.flowi4_tos;
+		fri.dscp = inet_dsfield_to_dscp(fl4.flowi4_tos);
 		fri.type = rt->rt_type;
 		fri.offload = 0;
 		fri.trap = 0;
@@ -3407,7 +3407,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 
 				if (fa->fa_slen == slen &&
 				    fa->tb_id == fri.tb_id &&
-				    fa->fa_dscp == inet_dsfield_to_dscp(fri.tos) &&
+				    fa->fa_dscp == fri.dscp &&
 				    fa->fa_info == res.fi &&
 				    fa->fa_type == fri.type) {
 					fri.offload = READ_ONCE(fa->offload);