#   endif /* BYTE_ORDER == BIG_ENDIAN */
#endif /* HTONS */

/**
 * Convert 16-bit quantity from host byte order to network byte order.
 *
 * This function is primarily used for converting variables from host
 * byte order to network byte order. For converting constants to
 * network byte order, use the HTONS() macro instead.
 */
#ifndef htons
u16_t htons(u16_t val);
#endif /* htons */

/** @} */

/**
 * Pointer to the application data in the packet buffer.
 *
 * This pointer points to the application data when the application is
 * called. If the application wishes to send data, the application may
 * use this space to write the data into before calling uip_send().
 */
extern volatile u8_t *uip_appdata;
extern volatile u8_t *uip_sappdata; 

#if UIP_URGDATA > 0 
/* u8_t *uip_urgdata:
 *
 * This pointer points to any urgent data that has been received. Only
 * present if compiled with support for urgent data (UIP_URGDATA).
 */
extern volatile u8_t *uip_urgdata; 
#endif /* UIP_URGDATA > 0 */


/* u[8|16]_t uip_len:
 *
 * When the application is called, uip_len contains the length of any
 * new data that has been received from the remote host. The
 * application should set this variable to the size of any data that
 * the application wishes to send. When the network device driver
 * output function is called, uip_len should contain the length of the
 * outgoing packet.
 */
extern volatile u16_t uip_len, uip_slen;

#if UIP_URGDATA > 0 
extern volatile u8_t uip_urglen, uip_surglen;
#endif /* UIP_URGDATA > 0 */


/**
 * Representation of a uIP TCP connection.
 *
 * The uip_conn structure is used for identifying a connection. All
 * but one field in the structure are to be considered read-only by an
 * application. The only exception is the appstate field whos purpose
 * is to let the application store application-specific state (e.g.,
 * file pointers) for the connection. The size of this field is
 * configured in the "uipopt.h" header file.
 */
struct uip_conn {
  u16_t ripaddr[2];   /**< The IP address of the remote host. */
  
  u16_t lport;        /**< The local TCP port, in network byte order. */
  u16_t rport;        /**< The local remote TCP port, in network byte
			 order. */  
  
  u8_t rcv_nxt[4];    /**< The sequence number that we expect to
			 receive next. */
  u8_t snd_nxt[4];    /**< The sequence number that was last sent by
                         us. */
  u16_t len;          /**< Length of the data that was previously sent. */
  u16_t mss;          /**< Current maximum segment size for the
			 connection. */
  u16_t initialmss;   /**< Initial maximum segment size for the
			 connection. */  
  u8_t sa;            /**< Retransmission time-out calculation state
			 variable. */
  u8_t sv;            /**< Retransmission time-out calculation state
			 variable. */
  u8_t rto;           /**< Retransmission time-out. */
  u8_t tcpstateflags; /**< TCP state and flags. */
  u8_t timer;         /**< The retransmission timer. */
  u8_t nrtx;          /**< The number of retransmissions for the last
			 segment sent. */

  /** The application state. */
  u8_t appstate[UIP_APPSTATE_SIZE];  
};


/* Pointer to the current connection. */
extern struct uip_conn *uip_conn;
/* The array containing all uIP connections. */
extern struct uip_conn uip_conns[UIP_CONNS];
/**
 * \addtogroup uiparch
 * @{
 */

/**
 * 4-byte array used for the 32-bit sequence number calculations.
 */
extern volatile u8_t uip_acc32[4];

/** @} */


#if UIP_UDP
/**
 * Representation of a uIP UDP connection.
 */
struct uip_udp_conn {
  u16_t ripaddr[2];   /**< The IP address of the remote peer. */
  u16_t lport;        /**< The local port number in network byte order. */
  u16_t rport;        /**< The remote port number in network byte order. */
};

extern struct uip_udp_conn *uip_udp_conn;
extern struct uip_udp_conn uip_udp_conns[UIP_UDP_CONNS];
#endif /* UIP_UDP */

/**
 * The structure holding the TCP/IP statistics that are gathered if
 * UIP_STATISTICS is set to 1.
 *
 */
struct uip_stats {
  struct {
    uip_stats_t drop;     /**< Number of dropped packets at the IP
			     layer. */
    uip_stats_t recv;     /**< Number of received packets at the IP
			     layer. */
    uip_stats_t sent;     /**< Number of sent packets at the IP
			     layer. */
    uip_stats_t vhlerr;   /**< Number of packets dropped due to wrong
			     IP version or header length. */
    uip_stats_t hblenerr; /**< Number of packets dropped due to wrong
			     IP length, high byte. */
    uip_stats_t lblenerr; /**< Number of packets dropped due to wrong
			     IP length, low byte. */
    uip_stats_t fragerr;  /**< Number of packets dropped since they
			     were IP fragments. */
    uip_stats_t chkerr;   /**< Number of packets dropped due to IP
			     checksum errors. */
    uip_stats_t protoerr; /**< Number of packets dropped since they
			     were neither ICMP, UDP nor TCP. */
  } ip;                   /**< IP statistics. */
  struct {
    uip_stats_t drop;     /**< Number of dropped ICMP packets. */
    uip_stats_t recv;     /**< Number of received ICMP packets. */
    uip_stats_t sent;     /**< Number of sent ICMP packets. */
    uip_stats_t typeerr;  /**< Number of ICMP packets with a wrong
			     type. */
  } icmp;                 /**< ICMP statistics. */
  struct {
    uip_stats_t drop;     /**< Number of dropped TCP segments. */
    uip_stats_t recv;     /**< Number of recived TCP segments. */
    uip_stats_t sent;     /**< Number of sent TCP segments. */
    uip_stats_t chkerr;   /**< Number of TCP segments with a bad
			     checksum. */
    uip_stats_t ackerr;   /**< Number of TCP segments with a bad ACK
			     number. */
    uip_stats_t rst;      /**< Number of recevied TCP RST (reset) segments. */
    uip_stats_t rexmit;   /**< Number of retransmitted TCP segments. */
    uip_stats_t syndrop;  /**< Number of dropped SYNs due to too few
			     connections was avaliable. */
    uip_stats_t synrst;   /**< Number of SYNs for closed ports,
			     triggering a RST. */
  } tcp;                  /**< TCP statistics. */
};

/**
 * The uIP TCP/IP statistics.
 *
 * This is the variable in which the uIP TCP/IP statistics are gathered.
 */
extern struct uip_stats uip_stat;


/*-----------------------------------------------------------------------------------*/
/* All the stuff below this point is internal to uIP and should not be
 * used directly by an application or by a device driver.
 */
/*-----------------------------------------------------------------------------------*/
/* u8_t uip_flags:
 *
 * When the application is called, uip_flags will contain the flags
 * that are defined in this file. Please read below for more
 * infomation.
 */
extern volatile u8_t uip_flags;

/* The following flags may be set in the global variable uip_flags
   before calling the application callback. The UIP_ACKDATA and
   UIP_NEWDATA flags may both be set at the same time, whereas the
   others are mutualy exclusive. Note that these flags should *NOT* be
   accessed directly, but through the uIP functions/macros. */

#define UIP_ACKDATA   1     /* Signifies that the outstanding data was
			       acked and the application should send
			       out new data instead of retransmitting
			       the last data. */
#define UIP_NEWDATA   2     /* Flags the fact that the peer has sent
			       us new data. */
#define UIP_REXMIT    4     /* Tells the application to retransmit the
			       data that was last sent. */
#define UIP_POLL      8     /* Used for polling the application, to
			       check if the application has data that
			       it wants to send. */
#define UIP_CLOSE     16    /* The remote host has closed the
			       connection, thus the connection has
			       gone away. Or the application signals
			       that it wants to close the
			       connection. */
#define UIP_ABORT     32    /* The remote host has aborted the
			       connection, thus the connection has
			       gone away. Or the application signals
			       that it wants to abort the
			       connection. */
#define UIP_CONNECTED 64    /* We have got a connection from a remote
                               host and have set up a new connection
                               for it, or an active connection has
                               been successfully established. */

#define UIP_TIMEDOUT  128   /* The connection has been aborted due to
			       too many retransmissions. */


/* uip_process(flag):
 *
 * The actual uIP function which does all the work.
 */
void uip_process(u8_t flag);

/* The following flags are passed as an argument to the uip_process()
   function. They are used to distinguish between the two cases where
   uip_process() is called. It can be called either because we have
   incoming data that should be processed, or because the periodic
   timer has fired. */

#define UIP_DATA    1     /* Tells uIP that there is incoming data in
                             the uip_buf buffer. The length of the
                             data is stored in the global variable
                             uip_len. */
#define UIP_TIMER   2     /* Tells uIP that the periodic timer has
                             fired. */
#if UIP_UDP
#define UIP_UDP_TIMER 3
#endif /* UIP_UDP */

/* The TCP states used in the uip_conn->tcpstateflags. */
#define CLOSED      0
#define SYN_RCVD    1
#define SYN_SENT    2
#define ESTABLISHED 3
#define FIN_WAIT_1  4
#define FIN_WAIT_2  5
#define CLOSING     6
#define TIME_WAIT   7
#define LAST_ACK    8
#define TS_MASK     15
  
#define UIP_STOPPED      16

#define UIP_TCPIP_HLEN 40

/* The TCP and IP headers. */
typedef struct {
  /* IP header. */
  u8_t vhl,
    tos,          
    len[2],       
    ipid[2],        
    ipoffset[2],  
    ttl,          
    proto;     
  u16_t ipchksum;
  u16_t srcipaddr[2], 
    destipaddr[2];
  
  /* TCP header. */
  u16_t srcport,
    destport;
  u8_t seqno[4],  
    ackno[4],
    tcpoffset,
    flags,
    wnd[2];     
  u16_t tcpchksum;
  u8_t urgp[2];
  u8_t optdata[4];
} uip_tcpip_hdr;

/* The ICMP and IP headers. */
typedef struct {
  /* IP header. */
  u8_t vhl,
    tos,          
    len[2],       
    ipid[2],        
    ipoffset[2],  
    ttl,          
    proto;     
  u16_t ipchksum;
  u16_t srcipaddr[2], 
    destipaddr[2];
  /* ICMP (echo) header. */
  u8_t type, icode;
  u16_t icmpchksum;
  u16_t id, seqno;  
} uip_icmpip_hdr;


/* The UDP and IP headers. */
typedef struct {
  /* IP header. */
  u8_t vhl,
    tos,          
    len[2],       
    ipid[2],        
    ipoffset[2],  
    ttl,          
    proto;     
  u16_t ipchksum;
  u16_t srcipaddr[2], 
    destipaddr[2];
  
  /* UDP header. */
  u16_t srcport,
    destport;
  u16_t udplen;
  u16_t udpchksum;
} uip_udpip_hdr;

#define UIP_PROTO_ICMP  1
#define UIP_PROTO_TCP   6
#define UIP_PROTO_UDP   17

#if UIP_FIXEDADDR
extern const u16_t uip_hostaddr[2];
#else /* UIP_FIXEDADDR */
extern u16_t uip_hostaddr[2];
#endif /* UIP_FIXEDADDR */

#endif /* __UIP_H__ */


/** @} */