#ifndef _UAPI_LINUX_DCCP_H
  #define _UAPI_LINUX_DCCP_H
  
  #include <linux/types.h>
  #include <asm/byteorder.h>
  
  /**
   * struct dccp_hdr - generic part of DCCP packet header
   *
   * @dccph_sport - Relevant port on the endpoint that sent this packet
   * @dccph_dport - Relevant port on the other endpoint
   * @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words
   * @dccph_ccval - Used by the HC-Sender CCID
   * @dccph_cscov - Parts of the packet that are covered by the Checksum field
   * @dccph_checksum - Internet checksum, depends on dccph_cscov
   * @dccph_x - 0 = 24 bit sequence number, 1 = 48
   * @dccph_type - packet type, see DCCP_PKT_ prefixed macros
   * @dccph_seq - sequence number high or low order 24 bits, depends on dccph_x
   */
  struct dccp_hdr {
  	__be16	dccph_sport,
  		dccph_dport;
  	__u8	dccph_doff;
  #if defined(__LITTLE_ENDIAN_BITFIELD)
  	__u8	dccph_cscov:4,
  		dccph_ccval:4;
  #elif defined(__BIG_ENDIAN_BITFIELD)
  	__u8	dccph_ccval:4,
  		dccph_cscov:4;
  #else
  #error  "Adjust your <asm/byteorder.h> defines"
  #endif
  	__sum16	dccph_checksum;
  #if defined(__LITTLE_ENDIAN_BITFIELD)
  	__u8	dccph_x:1,
  		dccph_type:4,
  		dccph_reserved:3;
  #elif defined(__BIG_ENDIAN_BITFIELD)
  	__u8	dccph_reserved:3,
  		dccph_type:4,
  		dccph_x:1;
  #else
  #error  "Adjust your <asm/byteorder.h> defines"
  #endif
  	__u8	dccph_seq2;
  	__be16	dccph_seq;
  };
  
  /**
   * struct dccp_hdr_ext - the low bits of a 48 bit seq packet
   *
   * @dccph_seq_low - low 24 bits of a 48 bit seq packet
   */
  struct dccp_hdr_ext {
  	__be32	dccph_seq_low;
  };
  
  /**
   * struct dccp_hdr_request - Connection initiation request header
   *
   * @dccph_req_service - Service to which the client app wants to connect
   */
  struct dccp_hdr_request {
  	__be32	dccph_req_service;
  };
  /**
   * struct dccp_hdr_ack_bits - acknowledgment bits common to most packets
   *
   * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
   * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
   */
  struct dccp_hdr_ack_bits {
  	__be16	dccph_reserved1;
  	__be16	dccph_ack_nr_high;
  	__be32	dccph_ack_nr_low;
  };
  /**
   * struct dccp_hdr_response - Connection initiation response header
   *
   * @dccph_resp_ack - 48 bit Acknowledgment Number Subheader (5.3)
   * @dccph_resp_service - Echoes the Service Code on a received DCCP-Request
   */
  struct dccp_hdr_response {
  	struct dccp_hdr_ack_bits	dccph_resp_ack;
  	__be32				dccph_resp_service;
  };
  
  /**
   * struct dccp_hdr_reset - Unconditionally shut down a connection
   *
   * @dccph_reset_ack - 48 bit Acknowledgment Number Subheader (5.6)
   * @dccph_reset_code - one of %dccp_reset_codes
   * @dccph_reset_data - the Data 1 ... Data 3 fields from 5.6
   */
  struct dccp_hdr_reset {
  	struct dccp_hdr_ack_bits	dccph_reset_ack;
  	__u8				dccph_reset_code,
  					dccph_reset_data[3];
  };
  
  enum dccp_pkt_type {
  	DCCP_PKT_REQUEST = 0,
  	DCCP_PKT_RESPONSE,
  	DCCP_PKT_DATA,
  	DCCP_PKT_ACK,
  	DCCP_PKT_DATAACK,
  	DCCP_PKT_CLOSEREQ,
  	DCCP_PKT_CLOSE,
  	DCCP_PKT_RESET,
  	DCCP_PKT_SYNC,
  	DCCP_PKT_SYNCACK,
  	DCCP_PKT_INVALID,
  };
  
  #define DCCP_NR_PKT_TYPES DCCP_PKT_INVALID
  
  static inline unsigned int dccp_packet_hdr_len(const __u8 type)
  {
  	if (type == DCCP_PKT_DATA)
  		return 0;
  	if (type == DCCP_PKT_DATAACK	||
  	    type == DCCP_PKT_ACK	||
  	    type == DCCP_PKT_SYNC	||
  	    type == DCCP_PKT_SYNCACK	||
  	    type == DCCP_PKT_CLOSE	||
  	    type == DCCP_PKT_CLOSEREQ)
  		return sizeof(struct dccp_hdr_ack_bits);
  	if (type == DCCP_PKT_REQUEST)
  		return sizeof(struct dccp_hdr_request);
  	if (type == DCCP_PKT_RESPONSE)
  		return sizeof(struct dccp_hdr_response);
  	return sizeof(struct dccp_hdr_reset);
  }
  enum dccp_reset_codes {
  	DCCP_RESET_CODE_UNSPECIFIED = 0,
  	DCCP_RESET_CODE_CLOSED,
  	DCCP_RESET_CODE_ABORTED,
  	DCCP_RESET_CODE_NO_CONNECTION,
  	DCCP_RESET_CODE_PACKET_ERROR,
  	DCCP_RESET_CODE_OPTION_ERROR,
  	DCCP_RESET_CODE_MANDATORY_ERROR,
  	DCCP_RESET_CODE_CONNECTION_REFUSED,
  	DCCP_RESET_CODE_BAD_SERVICE_CODE,
  	DCCP_RESET_CODE_TOO_BUSY,
  	DCCP_RESET_CODE_BAD_INIT_COOKIE,
  	DCCP_RESET_CODE_AGGRESSION_PENALTY,
  
  	DCCP_MAX_RESET_CODES		/* Leave at the end!  */
  };
  
  /* DCCP options */
  enum {
  	DCCPO_PADDING = 0,
  	DCCPO_MANDATORY = 1,
  	DCCPO_MIN_RESERVED = 3,
  	DCCPO_MAX_RESERVED = 31,
  	DCCPO_CHANGE_L = 32,
  	DCCPO_CONFIRM_L = 33,
  	DCCPO_CHANGE_R = 34,
  	DCCPO_CONFIRM_R = 35,
  	DCCPO_NDP_COUNT = 37,
  	DCCPO_ACK_VECTOR_0 = 38,
  	DCCPO_ACK_VECTOR_1 = 39,
  	DCCPO_TIMESTAMP = 41,
  	DCCPO_TIMESTAMP_ECHO = 42,
  	DCCPO_ELAPSED_TIME = 43,
  	DCCPO_MAX = 45,
  	DCCPO_MIN_RX_CCID_SPECIFIC = 128,	/* from sender to receiver */
  	DCCPO_MAX_RX_CCID_SPECIFIC = 191,
  	DCCPO_MIN_TX_CCID_SPECIFIC = 192,	/* from receiver to sender */
  	DCCPO_MAX_TX_CCID_SPECIFIC = 255,
  };
  /* maximum size of a single TLV-encoded DCCP option (sans type/len bytes) */
  #define DCCP_SINGLE_OPT_MAXLEN	253
  
  /* DCCP CCIDS */
  enum {
  	DCCPC_CCID2 = 2,
  	DCCPC_CCID3 = 3,
  };
  
  /* DCCP features (RFC 4340 section 6.4) */
  enum dccp_feature_numbers {
  	DCCPF_RESERVED = 0,
  	DCCPF_CCID = 1,
  	DCCPF_SHORT_SEQNOS = 2,
  	DCCPF_SEQUENCE_WINDOW = 3,
  	DCCPF_ECN_INCAPABLE = 4,
  	DCCPF_ACK_RATIO = 5,
  	DCCPF_SEND_ACK_VECTOR = 6,
  	DCCPF_SEND_NDP_COUNT = 7,
  	DCCPF_MIN_CSUM_COVER = 8,
  	DCCPF_DATA_CHECKSUM = 9,
  	/* 10-127 reserved */
  	DCCPF_MIN_CCID_SPECIFIC = 128,
  	DCCPF_SEND_LEV_RATE = 192,	/* RFC 4342, sec. 8.4 */
  	DCCPF_MAX_CCID_SPECIFIC = 255,
  };
  
  /* DCCP socket control message types for cmsg */
  enum dccp_cmsg_type {
  	DCCP_SCM_PRIORITY = 1,
  	DCCP_SCM_QPOLICY_MAX = 0xFFFF,
  	/* ^-- Up to here reserved exclusively for qpolicy parameters */
  	DCCP_SCM_MAX
  };
  
  /* DCCP priorities for outgoing/queued packets */
  enum dccp_packet_dequeueing_policy {
  	DCCPQ_POLICY_SIMPLE,
  	DCCPQ_POLICY_PRIO,
  	DCCPQ_POLICY_MAX
  };
  
  /* DCCP socket options */
  #define DCCP_SOCKOPT_PACKET_SIZE	1 /* XXX deprecated, without effect */
  #define DCCP_SOCKOPT_SERVICE		2
  #define DCCP_SOCKOPT_CHANGE_L		3
  #define DCCP_SOCKOPT_CHANGE_R		4
  #define DCCP_SOCKOPT_GET_CUR_MPS	5
  #define DCCP_SOCKOPT_SERVER_TIMEWAIT	6
  #define DCCP_SOCKOPT_SEND_CSCOV		10
  #define DCCP_SOCKOPT_RECV_CSCOV		11
  #define DCCP_SOCKOPT_AVAILABLE_CCIDS	12
  #define DCCP_SOCKOPT_CCID		13
  #define DCCP_SOCKOPT_TX_CCID		14
  #define DCCP_SOCKOPT_RX_CCID		15
  #define DCCP_SOCKOPT_QPOLICY_ID		16
  #define DCCP_SOCKOPT_QPOLICY_TXQLEN	17
  #define DCCP_SOCKOPT_CCID_RX_INFO	128
  #define DCCP_SOCKOPT_CCID_TX_INFO	192
  
  /* maximum number of services provided on the same listening port */
  #define DCCP_SERVICE_LIST_MAX_LEN      32
  
  
  #endif /* _UAPI_LINUX_DCCP_H */