[02/53] netfilter: gre: Use consistent GRE and PTTP header structure instead of the ones defined by netfilter

diff --git a/include/linux/netfilter/nf_conntrack_proto_gre.h b/include/linux/netfilter/nf_conntrack_proto_gre.h
index 0189747f2691..dee0acd0dd31 100644
--- a/include/linux/netfilter/nf_conntrack_proto_gre.h
+++ b/include/linux/netfilter/nf_conntrack_proto_gre.h
@@ -4,48 +4,6 @@ 
 #include <net/gre.h>
 #include <net/pptp.h>
 
-/* GRE PROTOCOL HEADER */
-
-/* GRE is a mess: Four different standards */
-struct gre_hdr {
-#if defined(__LITTLE_ENDIAN_BITFIELD)
-	__u16	rec:3,
-		srr:1,
-		seq:1,
-		key:1,
-		routing:1,
-		csum:1,
-		version:3,
-		reserved:4,
-		ack:1;
-#elif defined(__BIG_ENDIAN_BITFIELD)
-	__u16	csum:1,
-		routing:1,
-		key:1,
-		seq:1,
-		srr:1,
-		rec:3,
-		ack:1,
-		reserved:4,
-		version:3;
-#else
-#error "Adjust your <asm/byteorder.h> defines"
-#endif
-	__be16	protocol;
-};
-
-/* modified GRE header for PPTP */
-struct gre_hdr_pptp {
-	__u8   flags;		/* bitfield */
-	__u8   version;		/* should be GRE_VERSION_PPTP */
-	__be16 protocol;	/* should be GRE_PROTOCOL_PPTP */
-	__be16 payload_len;	/* size of ppp payload, not inc. gre header */
-	__be16 call_id;		/* peer's call_id for this session */
-	__be32 seq;		/* sequence number.  Present if S==1 */
-	__be32 ack;		/* seq number of highest packet received by */
-				/*  sender in this session */
-};
-
 struct nf_ct_gre {
 	unsigned int stream_timeout;
 	unsigned int timeout;
diff --git a/net/ipv4/netfilter/nf_nat_proto_gre.c b/net/ipv4/netfilter/nf_nat_proto_gre.c
index 93198d71dbb6..edf05002d674 100644
--- a/net/ipv4/netfilter/nf_nat_proto_gre.c
+++ b/net/ipv4/netfilter/nf_nat_proto_gre.c
@@ -88,8 +88,8 @@  gre_manip_pkt(struct sk_buff *skb,
 	      const struct nf_conntrack_tuple *tuple,
 	      enum nf_nat_manip_type maniptype)
 {
-	const struct gre_hdr *greh;
-	struct gre_hdr_pptp *pgreh;
+	const struct gre_base_hdr *greh;
+	struct pptp_gre_header *pgreh;
 
 	/* pgreh includes two optional 32bit fields which are not required
 	 * to be there.  That's where the magic '8' comes from */
@@ -97,18 +97,19 @@  gre_manip_pkt(struct sk_buff *skb,
 		return false;
 
 	greh = (void *)skb->data + hdroff;
-	pgreh = (struct gre_hdr_pptp *)greh;
+	pgreh = (struct pptp_gre_header *)greh;
 
 	/* we only have destination manip of a packet, since 'source key'
 	 * is not present in the packet itself */
 	if (maniptype != NF_NAT_MANIP_DST)
 		return true;
-	switch (greh->version) {
-	case ntohs(GRE_VERSION_0):
+
+	switch (greh->flags & GRE_VERSION) {
+	case GRE_VERSION_0:
 		/* We do not currently NAT any GREv0 packets.
 		 * Try to behave like "nf_nat_proto_unknown" */
 		break;
-	case ntohs(GRE_VERSION_1):
+	case 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 deb239a014e4..9a715f88b2f1 100644
--- a/net/netfilter/nf_conntrack_proto_gre.c
+++ b/net/netfilter/nf_conntrack_proto_gre.c
@@ -192,15 +192,15 @@  static bool gre_invert_tuple(struct nf_conntrack_tuple *tuple,
 static bool gre_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
 			     struct net *net, struct nf_conntrack_tuple *tuple)
 {
-	const struct gre_hdr_pptp *pgrehdr;
-	struct gre_hdr_pptp _pgrehdr;
+	const struct pptp_gre_header *pgrehdr;
+	struct pptp_gre_header _pgrehdr;
 	__be16 srckey;
-	const struct gre_hdr *grehdr;
-	struct gre_hdr _grehdr;
+	const struct gre_base_hdr *grehdr;
+	struct gre_base_hdr _grehdr;
 
 	/* first only delinearize old RFC1701 GRE header */
 	grehdr = skb_header_pointer(skb, dataoff, sizeof(_grehdr), &_grehdr);
-	if (!grehdr || grehdr->version != ntohs(GRE_VERSION_1)) {
+	if (!grehdr || (grehdr->flags & GRE_VERSION) != GRE_VERSION_1) {
 		/* try to behave like "nf_conntrack_proto_generic" */
 		tuple->src.u.all = 0;
 		tuple->dst.u.all = 0;
@@ -213,7 +213,7 @@  static bool gre_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
 		return true;
 
 	if (grehdr->protocol != GRE_PROTO_PPP) {
-		pr_debug("GRE_VERSION_PPTP but unknown proto\n");
+		pr_debug("Unsupported GRE proto(0x%x)\n", ntohs(grehdr->protocol));
 		return false;
 	}