[PATCH v2 1/2 net-next] netfilter: gre: Use consistent GRE_* macros instead of ones defined by netfilter.

From: Gao Feng <redacted>

There are already some GRE_* macros in kernel, so it is unnecessary
to define these macros. And remove some useless macros

Signed-off-by: Gao Feng <redacted>
---
 v2: Split the original patch to review easily
 v1: Intial patch

 include/linux/netfilter/nf_conntrack_proto_gre.h | 22 ++--------------------
 include/uapi/linux/if_tunnel.h                   |  1 +
 net/ipv4/netfilter/nf_nat_proto_gre.c            |  4 ++--
 net/netfilter/nf_conntrack_proto_gre.c           |  4 ++--
 4 files changed, 7 insertions(+), 24 deletions(-)

diff --git a/include/linux/netfilter/nf_conntrack_proto_gre.h b/include/linux/netfilter/nf_conntrack_proto_gre.h
index df78dc2..0189747 100644
--- a/include/linux/netfilter/nf_conntrack_proto_gre.h
+++ b/include/linux/netfilter/nf_conntrack_proto_gre.h

@@ -1,29 +1,11 @@
 #ifndef _CONNTRACK_PROTO_GRE_H
 #define _CONNTRACK_PROTO_GRE_H
 #include <asm/byteorder.h>
+#include <net/gre.h>
+#include <net/pptp.h>

 /* GRE PROTOCOL HEADER */

-/* GRE Version field */
-#define GRE_VERSION_1701       0x0
-#define GRE_VERSION_PPTP       0x1
-
-/* GRE Protocol field */
-#define GRE_PROTOCOL_PPTP      0x880B
-
-/* GRE Flags */
-#define GRE_FLAG_C             0x80
-#define GRE_FLAG_R             0x40
-#define GRE_FLAG_K             0x20
-#define GRE_FLAG_S             0x10
-#define GRE_FLAG_A             0x80
-
-#define GRE_IS_C(f)    ((f)&GRE_FLAG_C)
-#define GRE_IS_R(f)    ((f)&GRE_FLAG_R)
-#define GRE_IS_K(f)    ((f)&GRE_FLAG_K)
-#define GRE_IS_S(f)    ((f)&GRE_FLAG_S)
-#define GRE_IS_A(f)    ((f)&GRE_FLAG_A)
-
 /* GRE is a mess: Four different standards */
 struct gre_hdr {
 #if defined(__LITTLE_ENDIAN_BITFIELD)

diff --git a/include/uapi/linux/if_tunnel.h b/include/uapi/linux/if_tunnel.h
index 361b9f0..1b27e2c 100644
--- a/include/uapi/linux/if_tunnel.h
+++ b/include/uapi/linux/if_tunnel.h

@@ -36,6 +36,7 @@
 #define GRE_IS_REC(f)          ((f) & GRE_REC)
 #define GRE_IS_ACK(f)          ((f) & GRE_ACK)

+#define GRE_VERSION_0          __cpu_to_be16(0x0000)
 #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)

diff --git a/net/ipv4/netfilter/nf_nat_proto_gre.c b/net/ipv4/netfilter/nf_nat_proto_gre.c
index 9414923..93198d7 100644
--- a/net/ipv4/netfilter/nf_nat_proto_gre.c
+++ b/net/ipv4/netfilter/nf_nat_proto_gre.c

@@ -104,11 +104,11 @@ gre_manip_pkt(struct sk_buff *skb,
        if (maniptype != NF_NAT_MANIP_DST)
                return true;
        switch (greh->version) {
-       case GRE_VERSION_1701:
+       case ntohs(GRE_VERSION_0):
                /* We do not currently NAT any GREv0 packets.
                 * Try to behave like "nf_nat_proto_unknown" */
                break;
-       case GRE_VERSION_PPTP:
+       case ntohs(GRE_VERSION_1):
                pr_debug("call_id -> 0x%04x\n", ntohs(tuple->dst.u.gre.key));
                pgreh->call_id = tuple->dst.u.gre.key;
                break;

diff --git a/net/netfilter/nf_conntrack_proto_gre.c b/net/netfilter/nf_conntrack_proto_gre.c
index a96451a..deb239a 100644
--- a/net/netfilter/nf_conntrack_proto_gre.c
+++ b/net/netfilter/nf_conntrack_proto_gre.c

@@ -200,7 +200,7 @@ static bool gre_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,

        /* first only delinearize old RFC1701 GRE header */
        grehdr = skb_header_pointer(skb, dataoff, sizeof(_grehdr), &_grehdr);
-       if (!grehdr || grehdr->version != GRE_VERSION_PPTP) {
+       if (!grehdr || grehdr->version != ntohs(GRE_VERSION_1)) {
                /* try to behave like "nf_conntrack_proto_generic" */
                tuple->src.u.all = 0;
                tuple->dst.u.all = 0;

@@ -212,7 +212,7 @@ static bool gre_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
        if (!pgrehdr)
                return true;

-       if (ntohs(grehdr->protocol) != GRE_PROTOCOL_PPTP) {
+       if (grehdr->protocol != GRE_PROTO_PPP) {
                pr_debug("GRE_VERSION_PPTP but unknown proto\n");
                return false;
        }
--

1.9.1