ipv4: Prepare core ipv4 files to future .flowi4_tos conversion.

Continue preparing users of ->flowi4_tos (struct flowi4) to the future conversion of this field (from __u8 to dscp_t). The objective is to have type annotation to properly separate DSCP bits from ECN ones. This way we'll ensure that ECN doesn't interfere with DSCP and avoid regressions where it break routing descisions (fib rules in particular).

This series concentrates on some easy IPv4 conversions where ->flowi4_tos is set directly from an IPv4 header, so we can get the DSCP value using the ip4h_dscp() helper function.

Guillaume Nault (4):
ipv4: Prepare fib_compute_spec_dst() to future .flowi4_tos conversion.
ipv4: Prepare icmp_reply() to future .flowi4_tos conversion.
ipv4: Prepare ipmr_rt_fib_lookup() to future .flowi4_tos conversion.
ipv4: Prepare ip_rt_get_source() to future .flowi4_tos conversion.

 net/ipv4/fib_frontend.c | 2 +-
 net/ipv4/icmp.c         | 2 +-
 net/ipv4/ipmr.c         | 2 +-
 net/ipv4/route.c        | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

2.39.2

Use ip4h_dscp() to get the DSCP from the IPv4 header, then convert the dscp_t value to __u8 with inet_dscp_to_dsfield().

Then, when we'll convert .flowi4_tos to dscp_t, we'll just have to drop the inet_dscp_to_dsfield() call.

---
 net/ipv4/fib_frontend.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 53bd26315df5..0c9ce934b490 100644
@@ -293,7 +293,7 @@ __be32 fib_compute_spec_dst(struct sk_buff *skb)
 			.flowi4_iif = LOOPBACK_IFINDEX,
 			.flowi4_l3mdev = l3mdev_master_ifindex_rcu(dev),
 			.daddr = ip_hdr(skb)->saddr,
-			.flowi4_tos = ip_hdr(skb)->tos & INET_DSCP_MASK,
+			.flowi4_tos = inet_dscp_to_dsfield(ip4h_dscp(ip_hdr(skb))),
 			.flowi4_scope = scope,
 			.flowi4_mark = vmark ? skb->mark : 0,
 		};

2.39.2

Use ip4h_dscp() to get the DSCP from the IPv4 header, then convert the dscp_t value to __u8 with inet_dscp_to_dsfield().

Then, when we'll convert .flowi4_tos to dscp_t, we'll just have to drop the inet_dscp_to_dsfield() call.

---
 net/ipv4/icmp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 23664434922e..33eec844a5a0 100644
@@ -445,7 +445,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
 	fl4.saddr = saddr;
 	fl4.flowi4_mark = mark;
 	fl4.flowi4_uid = sock_net_uid(net, NULL);
-	fl4.flowi4_tos = ip_hdr(skb)->tos & INET_DSCP_MASK;
+	fl4.flowi4_tos = inet_dscp_to_dsfield(ip4h_dscp(ip_hdr(skb)));
 	fl4.flowi4_proto = IPPROTO_ICMP;
 	fl4.flowi4_oif = l3mdev_master_ifindex(skb->dev);
 	security_skb_classify_flow(skb, flowi4_to_flowi_common(&fl4));

2.39.2

Use ip4h_dscp() to get the DSCP from the IPv4 header, then convert the dscp_t value to __u8 with inet_dscp_to_dsfield().

Then, when we'll convert .flowi4_tos to dscp_t, we'll just have to drop the inet_dscp_to_dsfield() call.

---
 net/ipv4/ipmr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index b4fc443481ce..99e7cd0531d9 100644
@@ -2081,7 +2081,7 @@ static struct mr_table *ipmr_rt_fib_lookup(struct net *net, struct sk_buff *skb)
 	struct flowi4 fl4 = {
 		.daddr = iph->daddr,
 		.saddr = iph->saddr,
-		.flowi4_tos = iph->tos & INET_DSCP_MASK,
+		.flowi4_tos = inet_dscp_to_dsfield(ip4h_dscp(iph)),
 		.flowi4_oif = (rt_is_output_route(rt) ?
 			       skb->dev->ifindex : 0),
 		.flowi4_iif = (rt_is_output_route(rt) ?

2.39.2

Use ip4h_dscp() to get the DSCP from the IPv4 header, then convert the dscp_t value to __u8 with inet_dscp_to_dsfield().

Then, when we'll convert .flowi4_tos to dscp_t, we'll just have to drop the inet_dscp_to_dsfield() call.

---
 net/ipv4/route.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 18a08b4f4a5a..763398e08b7d 100644
@@ -1263,7 +1263,7 @@ void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
 		struct flowi4 fl4 = {
 			.daddr = iph->daddr,
 			.saddr = iph->saddr,
-			.flowi4_tos = iph->tos & INET_DSCP_MASK,
+			.flowi4_tos = inet_dscp_to_dsfield(ip4h_dscp(iph)),
 			.flowi4_oif = rt->dst.dev->ifindex,
 			.flowi4_iif = skb->dev->ifindex,
 			.flowi4_mark = skb->mark,

2.39.2