[PATCH net 1/2] net: sched: only keep the available bits when setting vxlan md->gbp

[Xin Long]

As we can see from vxlan_build/parse_gbp_hdr(), when processing metadata
on vxlan rx/tx path, only dont_learn/policy_applied/policy_id fields can
be set to or parse from the packet for vxlan gbp option.

So we'd better do the mask when set it in act_tunnel_key and cls_flower.
Otherwise, when users don't know these bits, they may configure with a
value which can never be matched.

Reported-by: Shuang Li <shu...@redhat.com>
Signed-off-by: Xin Long <lucien....@gmail.com>
---
 include/net/vxlan.h        | 3 +++
 net/sched/act_tunnel_key.c | 1 +
 net/sched/cls_flower.c     | 4 +++-
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index 3a41627c..08537aa 100644
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -121,6 +121,9 @@ struct vxlanhdr_gbp {
 #define VXLAN_GBP_POLICY_APPLIED       (BIT(3) << 16)
 #define VXLAN_GBP_ID_MASK              (0xFFFF)
 
+#define VXLAN_GBP_MASK (VXLAN_GBP_DONT_LEARN | VXLAN_GBP_POLICY_APPLIED | \
+                       VXLAN_GBP_ID_MASK)
+
 /*
  * VXLAN Generic Protocol Extension (VXLAN_F_GPE):
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c
index 536c4bc..37f1e10 100644
--- a/net/sched/act_tunnel_key.c
+++ b/net/sched/act_tunnel_key.c
@@ -156,6 +156,7 @@ tunnel_key_copy_vxlan_opt(const struct nlattr *nla, void 
*dst, int dst_len,
                struct vxlan_metadata *md = dst;
 
                md->gbp = nla_get_u32(tb[TCA_TUNNEL_KEY_ENC_OPT_VXLAN_GBP]);
+               md->gbp &= VXLAN_GBP_MASK;
        }
 
        return sizeof(struct vxlan_metadata);
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 19a8fa2..fed18fd 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -1175,8 +1175,10 @@ static int fl_set_vxlan_opt(const struct nlattr *nla, 
struct fl_flow_key *key,
                return -EINVAL;
        }
 
-       if (tb[TCA_FLOWER_KEY_ENC_OPT_VXLAN_GBP])
+       if (tb[TCA_FLOWER_KEY_ENC_OPT_VXLAN_GBP]) {
                md->gbp = nla_get_u32(tb[TCA_FLOWER_KEY_ENC_OPT_VXLAN_GBP]);
+               md->gbp &= VXLAN_GBP_MASK;
+       }
 
        return sizeof(*md);
 }
-- 
2.1.0