[PATCH net-next] net: DSCP in IPv4 routing

[Russell Strong]

TOS handling in ipv4 routing does not support using dscp.
This change widens masks to use the 6 DSCP bits in routing.

Tested with

ip rule add dsfield EF lookup main
ip rule
0:      from all lookup local
32765:  from all tos EF lookup main
32766:  from all lookup main
32767:  from all lookup default

and verified that lookups are indeed performed from the
correct table.

This now works instead of failing with "Error: Invalid tos."

Signed-off-by: Russell Strong <russ...@strong.id.au>
---
 include/net/route.h           | 2 +-
 include/uapi/linux/in_route.h | 2 +-
 include/uapi/linux/ip.h       | 2 ++
 net/ipv4/fib_rules.c          | 2 +-
 4 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/include/net/route.h b/include/net/route.h
index ff021cab657e..519448ad37d0 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -255,7 +255,7 @@ static inline void ip_rt_put(struct rtable *rt)
        dst_release(&rt->dst);
 }
 
-#define IPTOS_RT_MASK  (IPTOS_TOS_MASK & ~3)
+#define IPTOS_RT_MASK  (IPTOS_DS_MASK & ~3)
 
 extern const __u8 ip_tos2prio[16];
 
diff --git a/include/uapi/linux/in_route.h
b/include/uapi/linux/in_route.h index 0cc2c23b47f8..db5d236b9c50 100644
--- a/include/uapi/linux/in_route.h
+++ b/include/uapi/linux/in_route.h
@@ -28,6 +28,6 @@
 
 #define RTCF_NAT       (RTCF_DNAT|RTCF_SNAT)
 
-#define RT_TOS(tos)    ((tos)&IPTOS_TOS_MASK)
+#define RT_TOS(tos)    ((tos)&IPTOS_DS_MASK)
 
 #endif /* _LINUX_IN_ROUTE_H */
diff --git a/include/uapi/linux/ip.h b/include/uapi/linux/ip.h
index e42d13b55cf3..fafd9470ae78 100644
--- a/include/uapi/linux/ip.h
+++ b/include/uapi/linux/ip.h
@@ -20,6 +20,8 @@
 #include <linux/types.h>
 #include <asm/byteorder.h>
 
+#define IPTOS_DS_MASK          0xfc
+#define IPTOS_DS(tos)          ((tos)&IPTOS_DS_MASK)
 #define IPTOS_TOS_MASK         0x1E
 #define IPTOS_TOS(tos)         ((tos)&IPTOS_TOS_MASK)
 #define        IPTOS_LOWDELAY          0x10
diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index ce54a30c2ef1..1499105d1efd 100644
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -229,7 +229,7 @@ static int fib4_rule_configure(struct fib_rule
*rule, struct sk_buff *skb, int err = -EINVAL;
        struct fib4_rule *rule4 = (struct fib4_rule *) rule;
 
-       if (frh->tos & ~IPTOS_TOS_MASK) {
+       if (frh->tos & ~IPTOS_RT_MASK) {
                NL_SET_ERR_MSG(extack, "Invalid tos");
                goto errout;
        }
-- 
2.26.2