#ifndef _ULOGD_GRE_H_
#define _ULOGD_GRE_H_

#define GRE_FLAG_CKSUM  htons(0x8000)  /* Checksum Present */
#define GRE_FLAG_ROUTE  htons(0x4000)  /* Routing Present */
#define GRE_FLAG_KEY    htons(0x2000)  /* Key Present */
#define GRE_FLAG_SEQ    htons(0x1000)  /* Sequence Present */
#define GRE_FLAG_SSR    htons(0x0800)  /* Strict Source Route */
#define GRE_FLAG_RECUR  htons(0x0700)  /* Recursion Control */
#define GRE_FLAG_ACK    htons(0x0080)  /* Acknowledgement Present (PPTP only) */
#define GRE_FLAG_FLAGS  htons(0x0078)  /* Additional Flags */
#define GRE_FLAG_VER    htons(0x0007)  /* Version Number */
#define GRE_VER_GRE     htons(0x0000)  /* GRE version 0 (RFC1701 GRE) */
#define GRE_VER_PPTP    htons(0x0001)  /* Enhanced GRE (RFC2637 PPTP) */

struct grehdr {
  u_int16_t  flags_ver;          /* See above */
  u_int16_t  protocol;           /* Ethernet protocol type */
  u_int16_t  cksum;              /* present if (flags_ver & GRE_FLAG_CKSUM) */
  u_int16_t  reserved1;          /* present if (flags_ver & GRE_FLAG_CKSUM) */
  u_int32_t  key;                /* present if (flags_ver & GRE_FLAG_KEY) */
  u_int32_t  seq;                /* present if (flags_ver & GRE_FLAG_SEQ) */
};

struct pptphdr {
  u_int16_t  flags_ver;          /* See above */
  u_int16_t  protocol;           /* Ethernet protocol type */
  u_int16_t  payload_len;        /* following payload length (not including this header) */
  u_int16_t  call_id;            /* peer call ID */
  u_int32_t  seq;                /* present if (flags_ver & GRE_FLAG_SEQ) */
  u_int32_t  ack;                /* present if (flags_ver & GRE_FLAG_ACK) */
};

#endif  /* _ULOGD_GRE_H_ */