ipv4: udp: Unmask upper DSCP bits during early demux

Unmask the upper DSCP bits when performing source validation for
multicast packets during early demux. In the future, this will allow us
to perform the FIB lookup which is performed as part of source
validation according to the full DSCP value.

No functional changes intended since the upper DSCP bits are masked when
comparing against the TOS selectors in FIB rules and routes.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: Florian Westphal <fw@strlen.de>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20240821125251.1571445-12-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index ddb86baaea6c87a9645f3baa6e4ab695cd539de4..8accbf4cb2956a7334e2b455de55404a56e016ba 100644 (file)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -115,6 +115,7 @@
 #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
@@ -2618,7 +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 & IPTOS_RT_MASK,
+                                                    iph->tos & INET_DSCP_MASK,
                                                     skb->dev, in_dev, &itag);
        }
        return 0;