#ifndef _LINUX_DCCP_H
  #define _LINUX_DCCP_H

  
  #include <linux/in.h>

  #include <linux/interrupt.h>

  #include <linux/ktime.h>

  #include <linux/list.h>
  #include <linux/uio.h>
  #include <linux/workqueue.h>
  
  #include <net/inet_connection_sock.h>

  #include <net/inet_sock.h>

  #include <net/inet_timewait_sock.h>

  #include <net/tcp_states.h>

  #include <uapi/linux/dccp.h>

  
  enum dccp_state {

  	DCCP_OPEN	     = TCP_ESTABLISHED,
  	DCCP_REQUESTING	     = TCP_SYN_SENT,
  	DCCP_LISTEN	     = TCP_LISTEN,
  	DCCP_RESPOND	     = TCP_SYN_RECV,
  	/*
  	 * States involved in closing a DCCP connection:
  	 * 1) ACTIVE_CLOSEREQ is entered by a server sending a CloseReq.
  	 *
  	 * 2) CLOSING can have three different meanings (RFC 4340, 8.3):
  	 *  a. Client has performed active-close, has sent a Close to the server
  	 *     from state OPEN or PARTOPEN, and is waiting for the final Reset
  	 *     (in this case, SOCK_DONE == 1).
  	 *  b. Client is asked to perform passive-close, by receiving a CloseReq
  	 *     in (PART)OPEN state. It sends a Close and waits for final Reset
  	 *     (in this case, SOCK_DONE == 0).
  	 *  c. Server performs an active-close as in (a), keeps TIMEWAIT state.
  	 *
  	 * 3) The following intermediate states are employed to give passively
  	 *    closing nodes a chance to process their unread data:
  	 *    - PASSIVE_CLOSE    (from OPEN => CLOSED) and
  	 *    - PASSIVE_CLOSEREQ (from (PART)OPEN to CLOSING; case (b) above).
  	 */
  	DCCP_ACTIVE_CLOSEREQ = TCP_FIN_WAIT1,
  	DCCP_PASSIVE_CLOSE   = TCP_CLOSE_WAIT,	/* any node receiving a Close */
  	DCCP_CLOSING	     = TCP_CLOSING,
  	DCCP_TIME_WAIT	     = TCP_TIME_WAIT,
  	DCCP_CLOSED	     = TCP_CLOSE,

  	DCCP_NEW_SYN_RECV    = TCP_NEW_SYN_RECV,

  	DCCP_PARTOPEN	     = TCP_MAX_STATES,
  	DCCP_PASSIVE_CLOSEREQ,			/* clients receiving CloseReq */

  	DCCP_MAX_STATES

  };

  enum {

  	DCCPF_OPEN	      = TCPF_ESTABLISHED,
  	DCCPF_REQUESTING      = TCPF_SYN_SENT,
  	DCCPF_LISTEN	      = TCPF_LISTEN,
  	DCCPF_RESPOND	      = TCPF_SYN_RECV,
  	DCCPF_ACTIVE_CLOSEREQ = TCPF_FIN_WAIT1,
  	DCCPF_CLOSING	      = TCPF_CLOSING,
  	DCCPF_TIME_WAIT	      = TCPF_TIME_WAIT,
  	DCCPF_CLOSED	      = TCPF_CLOSE,

  	DCCPF_NEW_SYN_RECV    = TCPF_NEW_SYN_RECV,

  	DCCPF_PARTOPEN	      = (1 << DCCP_PARTOPEN),

  };
  
  static inline struct dccp_hdr *dccp_hdr(const struct sk_buff *skb)
  {

  	return (struct dccp_hdr *)skb_transport_header(skb);

  }

  static inline struct dccp_hdr *dccp_zeroed_hdr(struct sk_buff *skb, int headlen)
  {

  	skb_push(skb, headlen);
  	skb_reset_transport_header(skb);

  	return memset(skb_transport_header(skb), 0, headlen);

  }

  static inline struct dccp_hdr_ext *dccp_hdrx(const struct dccp_hdr *dh)

  {

  	return (struct dccp_hdr_ext *)((unsigned char *)dh + sizeof(*dh));

  }

  static inline unsigned int __dccp_basic_hdr_len(const struct dccp_hdr *dh)
  {
  	return sizeof(*dh) + (dh->dccph_x ? sizeof(struct dccp_hdr_ext) : 0);
  }

  static inline unsigned int dccp_basic_hdr_len(const struct sk_buff *skb)
  {
  	const struct dccp_hdr *dh = dccp_hdr(skb);

  	return __dccp_basic_hdr_len(dh);

  }

  static inline __u64 dccp_hdr_seq(const struct dccp_hdr *dh)

  {

  	__u64 seq_nr =  ntohs(dh->dccph_seq);

  
  	if (dh->dccph_x != 0)

  		seq_nr = (seq_nr << 32) + ntohl(dccp_hdrx(dh)->dccph_seq_low);

  	else
  		seq_nr += (u32)dh->dccph_seq2 << 16;

  
  	return seq_nr;
  }
  
  static inline struct dccp_hdr_request *dccp_hdr_request(struct sk_buff *skb)
  {

  	return (struct dccp_hdr_request *)(skb_transport_header(skb) +
  					   dccp_basic_hdr_len(skb));

  }
  
  static inline struct dccp_hdr_ack_bits *dccp_hdr_ack_bits(const struct sk_buff *skb)
  {

  	return (struct dccp_hdr_ack_bits *)(skb_transport_header(skb) +
  					    dccp_basic_hdr_len(skb));

  }
  
  static inline u64 dccp_hdr_ack_seq(const struct sk_buff *skb)
  {
  	const struct dccp_hdr_ack_bits *dhack = dccp_hdr_ack_bits(skb);

  	return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) + ntohl(dhack->dccph_ack_nr_low);

  }
  
  static inline struct dccp_hdr_response *dccp_hdr_response(struct sk_buff *skb)
  {

  	return (struct dccp_hdr_response *)(skb_transport_header(skb) +
  					    dccp_basic_hdr_len(skb));

  }
  
  static inline struct dccp_hdr_reset *dccp_hdr_reset(struct sk_buff *skb)
  {

  	return (struct dccp_hdr_reset *)(skb_transport_header(skb) +
  					 dccp_basic_hdr_len(skb));

  }

  static inline unsigned int __dccp_hdr_len(const struct dccp_hdr *dh)
  {
  	return __dccp_basic_hdr_len(dh) +
  	       dccp_packet_hdr_len(dh->dccph_type);
  }

  static inline unsigned int dccp_hdr_len(const struct sk_buff *skb)
  {

  	return __dccp_hdr_len(dccp_hdr(skb));

  }

  /**

   * struct dccp_request_sock  -  represent DCCP-specific connection request
   * @dreq_inet_rsk: structure inherited from

   * @dreq_iss: initial sequence number, sent on the first Response (RFC 4340, 7.1)
   * @dreq_gss: greatest sequence number sent (for retransmitted Responses)
   * @dreq_isr: initial sequence number received in the first Request
   * @dreq_gsr: greatest sequence number received (for retransmitted Request(s))

   * @dreq_service: service code present on the Request (there is just one)

   * @dreq_featneg: feature negotiation options for this connection

   * The following two fields are analogous to the ones in dccp_sock:
   * @dreq_timestamp_echo: last received timestamp to echo (13.1)
   * @dreq_timestamp_echo: the time of receiving the last @dreq_timestamp_echo
   */

  struct dccp_request_sock {
  	struct inet_request_sock dreq_inet_rsk;
  	__u64			 dreq_iss;

  	__u64			 dreq_gss;

  	__u64			 dreq_isr;

  	__u64			 dreq_gsr;

  	__be32			 dreq_service;

  	struct list_head	 dreq_featneg;

  	__u32			 dreq_timestamp_echo;
  	__u32			 dreq_timestamp_time;

  };
  
  static inline struct dccp_request_sock *dccp_rsk(const struct request_sock *req)
  {
  	return (struct dccp_request_sock *)req;
  }

  extern struct inet_timewait_death_row dccp_death_row;

  extern int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
  			      struct sk_buff *skb);

  struct dccp_options_received {

  	u64	dccpor_ndp:48;

  	u32	dccpor_timestamp;
  	u32	dccpor_timestamp_echo;
  	u32	dccpor_elapsed_time;
  };
  
  struct ccid;
  
  enum dccp_role {
  	DCCP_ROLE_UNDEFINED,
  	DCCP_ROLE_LISTEN,
  	DCCP_ROLE_CLIENT,
  	DCCP_ROLE_SERVER,
  };

  struct dccp_service_list {
  	__u32	dccpsl_nr;

  	__be32	dccpsl_list[0];

  };
  
  #define DCCP_SERVICE_INVALID_VALUE htonl((__u32)-1)

  #define DCCP_SERVICE_CODE_IS_ABSENT		0

  static inline bool dccp_list_has_service(const struct dccp_service_list *sl,

  					const __be32 service)

  {
  	if (likely(sl != NULL)) {
  		u32 i = sl->dccpsl_nr;
  		while (i--)
  			if (sl->dccpsl_list[i] == service)

  				return true;

  	}

  	return false;

  }

  struct dccp_ackvec;

  /**
   * struct dccp_sock - DCCP socket state
   *
   * @dccps_swl - sequence number window low
   * @dccps_swh - sequence number window high
   * @dccps_awl - acknowledgement number window low
   * @dccps_awh - acknowledgement number window high
   * @dccps_iss - initial sequence number sent
   * @dccps_isr - initial sequence number received
   * @dccps_osr - first OPEN sequence number received
   * @dccps_gss - greatest sequence number sent
   * @dccps_gsr - greatest valid sequence number received
   * @dccps_gar - greatest valid ack number received on a non-Sync; initialized to %dccps_iss

   * @dccps_service - first (passive sock) or unique (active sock) service code
   * @dccps_service_list - second .. last service code on passive socket

   * @dccps_timestamp_echo - latest timestamp received on a TIMESTAMP option

   * @dccps_timestamp_time - time of receiving latest @dccps_timestamp_echo

   * @dccps_l_ack_ratio - feature-local Ack Ratio
   * @dccps_r_ack_ratio - feature-remote Ack Ratio

   * @dccps_l_seq_win - local Sequence Window (influences ack number validity)
   * @dccps_r_seq_win - remote Sequence Window (influences seq number validity)

   * @dccps_pcslen - sender   partial checksum coverage (via sockopt)
   * @dccps_pcrlen - receiver partial checksum coverage (via sockopt)

   * @dccps_send_ndp_count - local Send NDP Count feature (7.7.2)

   * @dccps_ndp_count - number of Non Data Packets since last data packet

   * @dccps_mss_cache - current value of MSS (path MTU minus header sizes)

   * @dccps_rate_last - timestamp for rate-limiting DCCP-Sync (RFC 4340, 7.5.4)

   * @dccps_featneg - tracks feature-negotiation state (mostly during handshake)

   * @dccps_hc_rx_ackvec - rx half connection ack vector

   * @dccps_hc_rx_ccid - CCID used for the receiver (or receiving half-connection)
   * @dccps_hc_tx_ccid - CCID used for the sender (or sending half-connection)
   * @dccps_options_received - parsed set of retrieved options

   * @dccps_qpolicy - TX dequeueing policy, one of %dccp_packet_dequeueing_policy
   * @dccps_tx_qlen - maximum length of the TX queue

   * @dccps_role - role of this sock, one of %dccp_role
   * @dccps_hc_rx_insert_options - receiver wants to add options when acking
   * @dccps_hc_tx_insert_options - sender wants to add options when sending

   * @dccps_server_timewait - server holds timewait state on close (RFC 4340, 8.3)

   * @dccps_sync_scheduled - flag which signals "send out-of-band message soon"

   * @dccps_xmitlet - tasklet scheduled by the TX CCID to dequeue data packets
   * @dccps_xmit_timer - used by the TX CCID to delay sending (rate-based pacing)

   * @dccps_syn_rtt - RTT sample from Request/Response exchange (in usecs)

   */
  struct dccp_sock {
  	/* inet_connection_sock has to be the first member of dccp_sock */
  	struct inet_connection_sock	dccps_inet_connection;

  #define dccps_syn_rtt			dccps_inet_connection.icsk_ack.lrcvtime

  	__u64				dccps_swl;
  	__u64				dccps_swh;
  	__u64				dccps_awl;
  	__u64				dccps_awh;
  	__u64				dccps_iss;
  	__u64				dccps_isr;
  	__u64				dccps_osr;
  	__u64				dccps_gss;
  	__u64				dccps_gsr;
  	__u64				dccps_gar;

  	__be32				dccps_service;

  	__u32				dccps_mss_cache;

  	struct dccp_service_list	*dccps_service_list;

  	__u32				dccps_timestamp_echo;

  	__u32				dccps_timestamp_time;

  	__u16				dccps_l_ack_ratio;
  	__u16				dccps_r_ack_ratio;

  	__u64				dccps_l_seq_win:48;
  	__u64				dccps_r_seq_win:48;

  	__u8				dccps_pcslen:4;
  	__u8				dccps_pcrlen:4;

  	__u8				dccps_send_ndp_count:1;

  	__u64				dccps_ndp_count:48;

  	unsigned long			dccps_rate_last;

  	struct list_head		dccps_featneg;

  	struct dccp_ackvec		*dccps_hc_rx_ackvec;

  	struct ccid			*dccps_hc_rx_ccid;
  	struct ccid			*dccps_hc_tx_ccid;
  	struct dccp_options_received	dccps_options_received;

  	__u8				dccps_qpolicy;
  	__u32				dccps_tx_qlen;

  	enum dccp_role			dccps_role:2;

  	__u8				dccps_hc_rx_insert_options:1;
  	__u8				dccps_hc_tx_insert_options:1;

  	__u8				dccps_server_timewait:1;

  	__u8				dccps_sync_scheduled:1;

  	struct tasklet_struct		dccps_xmitlet;

  	struct timer_list		dccps_xmit_timer;

  };

  static inline struct dccp_sock *dccp_sk(const struct sock *sk)
  {
  	return (struct dccp_sock *)sk;
  }
  
  static inline const char *dccp_role(const struct sock *sk)
  {
  	switch (dccp_sk(sk)->dccps_role) {
  	case DCCP_ROLE_UNDEFINED: return "undefined";
  	case DCCP_ROLE_LISTEN:	  return "listen";
  	case DCCP_ROLE_SERVER:	  return "server";
  	case DCCP_ROLE_CLIENT:	  return "client";
  	}
  	return NULL;
  }

  extern void dccp_syn_ack_timeout(const struct request_sock *req);

  #endif /* _LINUX_DCCP_H */