From f09943fefe6b702e40893d35b4f10fd1064037fe Mon Sep 17 00:00:00 2001
From: Patrick McHardy <kaber@trash.net>
Date: Sat, 2 Dec 2006 22:09:41 -0800
Subject: [NETFILTER]: nf_conntrack/nf_nat: add PPTP helper port

Add nf_conntrack port of the PPtP conntrack/NAT helper. Since there seems
to be no IPv6-capable PPtP implementation the helper only support IPv4.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/linux/netfilter/nf_conntrack_proto_gre.h | 112 +++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 include/linux/netfilter/nf_conntrack_proto_gre.h

(limited to 'include/linux/netfilter/nf_conntrack_proto_gre.h')

diff --git a/include/linux/netfilter/nf_conntrack_proto_gre.h b/include/linux/netfilter/nf_conntrack_proto_gre.h
new file mode 100644
index 000000000000..4e6bbce04ff8
--- /dev/null
+++ b/include/linux/netfilter/nf_conntrack_proto_gre.h
@@ -0,0 +1,112 @@
+#ifndef _CONNTRACK_PROTO_GRE_H
+#define _CONNTRACK_PROTO_GRE_H
+#include <asm/byteorder.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)
+	__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 recieved by */
+				/*  sender in this session */
+};
+
+struct nf_ct_gre {
+	unsigned int stream_timeout;
+	unsigned int timeout;
+};
+
+#ifdef __KERNEL__
+#include <net/netfilter/nf_conntrack_tuple.h>
+
+struct nf_conn;
+
+/* structure for original <-> reply keymap */
+struct nf_ct_gre_keymap {
+	struct list_head list;
+	struct nf_conntrack_tuple tuple;
+};
+
+/* add new tuple->key_reply pair to keymap */
+int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir,
+			 struct nf_conntrack_tuple *t);
+
+/* delete keymap entries */
+void nf_ct_gre_keymap_destroy(struct nf_conn *ct);
+
+/* get pointer to gre key, if present */
+static inline __be32 *gre_key(struct gre_hdr *greh)
+{
+	if (!greh->key)
+		return NULL;
+	if (greh->csum || greh->routing)
+		return (__be32 *)(greh+sizeof(*greh)+4);
+	return (__be32 *)(greh+sizeof(*greh));
+}
+
+/* get pointer ot gre csum, if present */
+static inline __sum16 *gre_csum(struct gre_hdr *greh)
+{
+	if (!greh->csum)
+		return NULL;
+	return (__sum16 *)(greh+sizeof(*greh));
+}
+
+extern void nf_ct_gre_keymap_flush(void);
+extern void nf_nat_need_gre(void);
+
+#endif /* __KERNEL__ */
+#endif /* _CONNTRACK_PROTO_GRE_H */
-- 
cgit v1.2.3-59-g8ed1b