pptp: Refactor the struct and macros of PPTP codes

1. Use struct gre_base_hdr directly in pptp_gre_header instead of
duplicated members;
2. Use existing macros like GRE_KEY, GRE_SEQ, and so on instead of
duplicated macros defined by PPTP;
3. Add new macros like GRE_IS_ACK/SEQ and so on instead of
PPTP_GRE_IS_A/S and so on;

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Reviewed-by: Philip Prindeville <philipp@redfish-solutions.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 2 deletions

diff --git a/include/uapi/linux/if_tunnel.h b/include/uapi/linux/if_tunnel.h
index 60dbb200de60..361b9f0f20d7 100644
--- a/include/uapi/linux/if_tunnel.h
+++ b/include/uapi/linux/if_tunnel.h
@@ -28,8 +28,16 @@
 #define GRE_FLAGS       __cpu_to_be16(0x0078)
 #define GRE_VERSION     __cpu_to_be16(0x0007)
 
-#define GRE_VERSION_1   __cpu_to_be16(0x0001)
-#define GRE_PROTO_PPP   __cpu_to_be16(0x880b)
+#define GRE_IS_CSUM(f)          ((f) & GRE_CSUM)
+#define GRE_IS_ROUTING(f)       ((f) & GRE_ROUTING)
+#define GRE_IS_KEY(f)           ((f) & GRE_KEY)
+#define GRE_IS_SEQ(f)           ((f) & GRE_SEQ)
+#define GRE_IS_STRICT(f)        ((f) & GRE_STRICT)
+#define GRE_IS_REC(f)           ((f) & GRE_REC)
+#define GRE_IS_ACK(f)           ((f) & GRE_ACK)
+
+#define GRE_VERSION_1           __cpu_to_be16(0x0001)
+#define GRE_PROTO_PPP           __cpu_to_be16(0x880b)
 #define GRE_PPTP_KEY_MASK       __cpu_to_be32(0xffff)
 
 struct ip_tunnel_parm {