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#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 */
};
/* this is part of ip_conntrack */
struct ip_ct_gre {
unsigned int stream_timeout;
unsigned int timeout;
};
#ifdef __KERNEL__
struct ip_conntrack_expect;
struct ip_conntrack;
/* structure for original <-> reply keymap */
struct ip_ct_gre_keymap {
struct list_head list;
struct ip_conntrack_tuple tuple;
};
/* add new tuple->key_reply pair to keymap */
int ip_ct_gre_keymap_add(struct ip_conntrack *ct,
struct ip_conntrack_tuple *t,
int reply);
/* delete keymap entries */
void ip_ct_gre_keymap_destroy(struct ip_conntrack *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));
}
#endif /* __KERNEL__ */
#endif /* _CONNTRACK_PROTO_GRE_H */
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