/* SCTP kernel reference Implementation
   * (C) Copyright IBM Corp. 2001, 2004
   * Copyright (c) 1999-2000 Cisco, Inc.
   * Copyright (c) 1999-2001 Motorola, Inc.
   * Copyright (c) 2001 Intel Corp.
   * Copyright (c) 2001 Nokia, Inc.
   * Copyright (c) 2001 La Monte H.P. Yarroll
   *
   * This file is part of the SCTP kernel reference Implementation
   *
   * Various protocol defined structures.
   *

   * This SCTP implementation is free software;

   * you can redistribute it and/or modify it under the terms of
   * the GNU General Public License as published by
   * the Free Software Foundation; either version 2, or (at your option)
   * any later version.
   *

   * This SCTP implementation is distributed in the hope that it

   * will be useful, but WITHOUT ANY WARRANTY; without even the implied
   *                 ************************
   * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   * See the GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with GNU CC; see the file COPYING.  If not, write to
   * the Free Software Foundation, 59 Temple Place - Suite 330,
   * Boston, MA 02111-1307, USA.
   *
   * Please send any bug reports or fixes you make to the
   * email address(es):
   *    lksctp developers <lksctp-developerst@lists.sourceforge.net>
   *
   * Or submit a bug report through the following website:
   *    http://www.sf.net/projects/lksctp
   *
   * Written or modified by:
   *    La Monte H.P. Yarroll <piggy@acm.org>
   *    Karl Knutson <karl@athena.chicago.il.us>
   *    Jon Grimm <jgrimm@us.ibm.com>
   *    Xingang Guo <xingang.guo@intel.com>
   *    randall@sctp.chicago.il.us
   *    kmorneau@cisco.com
   *    qxie1@email.mot.com
   *    Sridhar Samudrala <sri@us.ibm.com>
   *    Kevin Gao <kevin.gao@intel.com>
   *
   * Any bugs reported given to us we will try to fix... any fixes shared will
   * be incorporated into the next SCTP release.
   */
  #ifndef __LINUX_SCTP_H__
  #define __LINUX_SCTP_H__
  
  #include <linux/in.h>		/* We need in_addr.  */
  #include <linux/in6.h>		/* We need in6_addr.  */
  
  
  /* Section 3.1.  SCTP Common Header Format */
  typedef struct sctphdr {

  	__be16 source;
  	__be16 dest;
  	__be32 vtag;
  	__be32 checksum;

  } __attribute__((packed)) sctp_sctphdr_t;

  #ifdef __KERNEL__
  #include <linux/skbuff.h>
  
  static inline struct sctphdr *sctp_hdr(const struct sk_buff *skb)
  {

  	return (struct sctphdr *)skb_transport_header(skb);

  }
  #endif

  /* Section 3.2.  Chunk Field Descriptions. */
  typedef struct sctp_chunkhdr {
  	__u8 type;
  	__u8 flags;

  	__be16 length;

  } __attribute__((packed)) sctp_chunkhdr_t;
  
  
  /* Section 3.2.  Chunk Type Values.
   * [Chunk Type] identifies the type of information contained in the Chunk
   * Value field. It takes a value from 0 to 254. The value of 255 is
   * reserved for future use as an extension field.
   */
  typedef enum {
  	SCTP_CID_DATA			= 0,
          SCTP_CID_INIT			= 1,
          SCTP_CID_INIT_ACK		= 2,
          SCTP_CID_SACK			= 3,
          SCTP_CID_HEARTBEAT		= 4,
          SCTP_CID_HEARTBEAT_ACK		= 5,
          SCTP_CID_ABORT			= 6,
          SCTP_CID_SHUTDOWN		= 7,
          SCTP_CID_SHUTDOWN_ACK		= 8,
          SCTP_CID_ERROR			= 9,
          SCTP_CID_COOKIE_ECHO		= 10,
          SCTP_CID_COOKIE_ACK	        = 11,
          SCTP_CID_ECN_ECNE		= 12,
          SCTP_CID_ECN_CWR		= 13,
          SCTP_CID_SHUTDOWN_COMPLETE	= 14,

  	/* AUTH Extension Section 4.1 */
  	SCTP_CID_AUTH			= 0x0F,

  	/* PR-SCTP Sec 3.2 */
  	SCTP_CID_FWD_TSN		= 0xC0,
  
  	/* Use hex, as defined in ADDIP sec. 3.1 */
  	SCTP_CID_ASCONF			= 0xC1,
  	SCTP_CID_ASCONF_ACK		= 0x80,
  } sctp_cid_t; /* enum */
  
  
  /* Section 3.2
   *  Chunk Types are encoded such that the highest-order two bits specify
   *  the action that must be taken if the processing endpoint does not
   *  recognize the Chunk Type.
   */
  typedef enum {
  	SCTP_CID_ACTION_DISCARD     = 0x00,
  	SCTP_CID_ACTION_DISCARD_ERR = 0x40,
  	SCTP_CID_ACTION_SKIP        = 0x80,
  	SCTP_CID_ACTION_SKIP_ERR    = 0xc0,
  } sctp_cid_action_t;
  
  enum { SCTP_CID_ACTION_MASK = 0xc0, };
  
  /* This flag is used in Chunk Flags for ABORT and SHUTDOWN COMPLETE.
   *
   * 3.3.7 Abort Association (ABORT) (6):
   *    The T bit is set to 0 if the sender had a TCB that it destroyed.
   *    If the sender did not have a TCB it should set this bit to 1.
   */
  enum { SCTP_CHUNK_FLAG_T = 0x01 };
  
  /*
   *  Set the T bit
   *
   *      0                   1                   2                   3
   *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *     |   Type = 14   |Reserved     |T|      Length = 4               |
   *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *
   * Chunk Flags: 8 bits
   *
   *   Reserved:  7 bits
   *     Set to 0 on transmit and ignored on receipt.
   *
   *   T bit:  1 bit
   *     The T bit is set to 0 if the sender had a TCB that it destroyed. If
   *     the sender did NOT have a TCB it should set this bit to 1.
   *
   * Note: Special rules apply to this chunk for verification, please
   * see Section 8.5.1 for details.
   */
  
  #define sctp_test_T_bit(c)    ((c)->chunk_hdr->flags & SCTP_CHUNK_FLAG_T)
  
  /* RFC 2960
   * Section 3.2.1 Optional/Variable-length Parmaeter Format.
   */
  
  typedef struct sctp_paramhdr {

  	__be16 type;
  	__be16 length;

  } __attribute__((packed)) sctp_paramhdr_t;
  
  typedef enum {
  
  	/* RFC 2960 Section 3.3.5 */
  	SCTP_PARAM_HEARTBEAT_INFO		= __constant_htons(1),
  	/* RFC 2960 Section 3.3.2.1 */
  	SCTP_PARAM_IPV4_ADDRESS			= __constant_htons(5),
  	SCTP_PARAM_IPV6_ADDRESS			= __constant_htons(6),
  	SCTP_PARAM_STATE_COOKIE			= __constant_htons(7),
  	SCTP_PARAM_UNRECOGNIZED_PARAMETERS	= __constant_htons(8),
  	SCTP_PARAM_COOKIE_PRESERVATIVE		= __constant_htons(9),
  	SCTP_PARAM_HOST_NAME_ADDRESS		= __constant_htons(11),
  	SCTP_PARAM_SUPPORTED_ADDRESS_TYPES	= __constant_htons(12),
  	SCTP_PARAM_ECN_CAPABLE			= __constant_htons(0x8000),

  	/* AUTH Extension Section 3 */
  	SCTP_PARAM_RANDOM			= __constant_htons(0x8002),
  	SCTP_PARAM_CHUNKS			= __constant_htons(0x8003),
  	SCTP_PARAM_HMAC_ALGO			= __constant_htons(0x8004),

  	/* Add-IP: Supported Extensions, Section 4.2 */
  	SCTP_PARAM_SUPPORTED_EXT	= __constant_htons(0x8008),

  	/* PR-SCTP Sec 3.1 */
  	SCTP_PARAM_FWD_TSN_SUPPORT	= __constant_htons(0xc000),
  
  	/* Add-IP Extension. Section 3.2 */
  	SCTP_PARAM_ADD_IP		= __constant_htons(0xc001),
  	SCTP_PARAM_DEL_IP		= __constant_htons(0xc002),
  	SCTP_PARAM_ERR_CAUSE		= __constant_htons(0xc003),
  	SCTP_PARAM_SET_PRIMARY		= __constant_htons(0xc004),
  	SCTP_PARAM_SUCCESS_REPORT	= __constant_htons(0xc005),

  	SCTP_PARAM_ADAPTATION_LAYER_IND = __constant_htons(0xc006),

  
  } sctp_param_t; /* enum */
  
  
  /* RFC 2960 Section 3.2.1
   *  The Parameter Types are encoded such that the highest-order two bits
   *  specify the action that must be taken if the processing endpoint does
   *  not recognize the Parameter Type.
   *
   */
  typedef enum {
  	SCTP_PARAM_ACTION_DISCARD     = __constant_htons(0x0000),
  	SCTP_PARAM_ACTION_DISCARD_ERR = __constant_htons(0x4000),
  	SCTP_PARAM_ACTION_SKIP        = __constant_htons(0x8000),
  	SCTP_PARAM_ACTION_SKIP_ERR    = __constant_htons(0xc000),
  } sctp_param_action_t;
  
  enum { SCTP_PARAM_ACTION_MASK = __constant_htons(0xc000), };
  
  /* RFC 2960 Section 3.3.1 Payload Data (DATA) (0) */
  
  typedef struct sctp_datahdr {

  	__be32 tsn;
  	__be16 stream;
  	__be16 ssn;
  	__be32 ppid;

  	__u8  payload[0];
  } __attribute__((packed)) sctp_datahdr_t;
  
  typedef struct sctp_data_chunk {
          sctp_chunkhdr_t chunk_hdr;
          sctp_datahdr_t  data_hdr;
  } __attribute__((packed)) sctp_data_chunk_t;
  
  /* DATA Chuck Specific Flags */
  enum {
  	SCTP_DATA_MIDDLE_FRAG	= 0x00,
  	SCTP_DATA_LAST_FRAG	= 0x01,
  	SCTP_DATA_FIRST_FRAG	= 0x02,
  	SCTP_DATA_NOT_FRAG	= 0x03,
  	SCTP_DATA_UNORDERED	= 0x04,
  };
  enum { SCTP_DATA_FRAG_MASK = 0x03, };
  
  
  /* RFC 2960 Section 3.3.2 Initiation (INIT) (1)
   *
   *  This chunk is used to initiate a SCTP association between two
   *  endpoints.
   */
  typedef struct sctp_inithdr {

  	__be32 init_tag;
  	__be32 a_rwnd;
  	__be16 num_outbound_streams;
  	__be16 num_inbound_streams;
  	__be32 initial_tsn;

  	__u8  params[0];
  } __attribute__((packed)) sctp_inithdr_t;
  
  typedef struct sctp_init_chunk {
  	sctp_chunkhdr_t chunk_hdr;
  	sctp_inithdr_t init_hdr;
  } __attribute__((packed)) sctp_init_chunk_t;
  
  
  /* Section 3.3.2.1. IPv4 Address Parameter (5) */
  typedef struct sctp_ipv4addr_param {
  	sctp_paramhdr_t param_hdr;
  	struct in_addr  addr;
  } __attribute__((packed)) sctp_ipv4addr_param_t;
  
  /* Section 3.3.2.1. IPv6 Address Parameter (6) */
  typedef struct sctp_ipv6addr_param {
  	sctp_paramhdr_t param_hdr;
  	struct in6_addr addr;
  } __attribute__((packed)) sctp_ipv6addr_param_t;
  
  /* Section 3.3.2.1 Cookie Preservative (9) */
  typedef struct sctp_cookie_preserve_param {
  	sctp_paramhdr_t param_hdr;

  	__be32          lifespan_increment;

  } __attribute__((packed)) sctp_cookie_preserve_param_t;
  
  /* Section 3.3.2.1 Host Name Address (11) */
  typedef struct sctp_hostname_param {
  	sctp_paramhdr_t param_hdr;
  	uint8_t hostname[0];
  } __attribute__((packed)) sctp_hostname_param_t;
  
  /* Section 3.3.2.1 Supported Address Types (12) */
  typedef struct sctp_supported_addrs_param {
  	sctp_paramhdr_t param_hdr;

  	__be16 types[0];

  } __attribute__((packed)) sctp_supported_addrs_param_t;
  
  /* Appendix A. ECN Capable (32768) */
  typedef struct sctp_ecn_capable_param {
  	sctp_paramhdr_t param_hdr;
  } __attribute__((packed)) sctp_ecn_capable_param_t;

  /* ADDIP Section 3.2.6 Adaptation Layer Indication */
  typedef struct sctp_adaptation_ind_param {

  	struct sctp_paramhdr param_hdr;

  	__be32 adaptation_ind;
  } __attribute__((packed)) sctp_adaptation_ind_param_t;

  /* ADDIP Section 4.2.7 Supported Extensions Parameter */
  typedef struct sctp_supported_ext_param {
  	struct sctp_paramhdr param_hdr;
  	__u8 chunks[0];
  } __attribute__((packed)) sctp_supported_ext_param_t;

  /* AUTH Section 3.1 Random */
  typedef struct sctp_random_param {
  	sctp_paramhdr_t param_hdr;
  	__u8 random_val[0];
  } __attribute__((packed)) sctp_random_param_t;
  
  /* AUTH Section 3.2 Chunk List */
  typedef struct sctp_chunks_param {
  	sctp_paramhdr_t param_hdr;
  	__u8 chunks[0];
  } __attribute__((packed)) sctp_chunks_param_t;
  
  /* AUTH Section 3.3 HMAC Algorithm */
  typedef struct sctp_hmac_algo_param {
  	sctp_paramhdr_t param_hdr;
  	__be16 hmac_ids[0];
  } __attribute__((packed)) sctp_hmac_algo_param_t;

  /* RFC 2960.  Section 3.3.3 Initiation Acknowledgement (INIT ACK) (2):
   *   The INIT ACK chunk is used to acknowledge the initiation of an SCTP
   *   association.
   */
  typedef sctp_init_chunk_t sctp_initack_chunk_t;
  
  /* Section 3.3.3.1 State Cookie (7) */
  typedef struct sctp_cookie_param {
  	sctp_paramhdr_t p;
  	__u8 body[0];
  } __attribute__((packed)) sctp_cookie_param_t;
  
  /* Section 3.3.3.1 Unrecognized Parameters (8) */
  typedef struct sctp_unrecognized_param {
  	sctp_paramhdr_t param_hdr;
  	sctp_paramhdr_t unrecognized;
  } __attribute__((packed)) sctp_unrecognized_param_t;
  
  
  
  /*
   * 3.3.4 Selective Acknowledgement (SACK) (3):
   *
   *  This chunk is sent to the peer endpoint to acknowledge received DATA
   *  chunks and to inform the peer endpoint of gaps in the received
   *  subsequences of DATA chunks as represented by their TSNs.
   */
  
  typedef struct sctp_gap_ack_block {

  	__be16 start;
  	__be16 end;

  } __attribute__((packed)) sctp_gap_ack_block_t;

  typedef __be32 sctp_dup_tsn_t;

  
  typedef union {
  	sctp_gap_ack_block_t	gab;
          sctp_dup_tsn_t		dup;
  } sctp_sack_variable_t;
  
  typedef struct sctp_sackhdr {

  	__be32 cum_tsn_ack;
  	__be32 a_rwnd;
  	__be16 num_gap_ack_blocks;
  	__be16 num_dup_tsns;

  	sctp_sack_variable_t variable[0];
  } __attribute__((packed)) sctp_sackhdr_t;
  
  typedef struct sctp_sack_chunk {
  	sctp_chunkhdr_t chunk_hdr;
  	sctp_sackhdr_t sack_hdr;
  } __attribute__((packed)) sctp_sack_chunk_t;
  
  
  /* RFC 2960.  Section 3.3.5 Heartbeat Request (HEARTBEAT) (4):
   *
   *  An endpoint should send this chunk to its peer endpoint to probe the
   *  reachability of a particular destination transport address defined in
   *  the present association.
   */
  
  typedef struct sctp_heartbeathdr {
  	sctp_paramhdr_t info;
  } __attribute__((packed)) sctp_heartbeathdr_t;
  
  typedef struct sctp_heartbeat_chunk {
  	sctp_chunkhdr_t chunk_hdr;
  	sctp_heartbeathdr_t hb_hdr;
  } __attribute__((packed)) sctp_heartbeat_chunk_t;
  
  
  /* For the abort and shutdown ACK we must carry the init tag in the
   * common header. Just the common header is all that is needed with a
   * chunk descriptor.
   */
  typedef struct sctp_abort_chunk {
          sctp_chunkhdr_t uh;
  } __attribute__((packed)) sctp_abort_chunk_t;
  
  
  /* For the graceful shutdown we must carry the tag (in common header)
   * and the highest consecutive acking value.
   */
  typedef struct sctp_shutdownhdr {

  	__be32 cum_tsn_ack;

  } __attribute__((packed)) sctp_shutdownhdr_t;
  
  struct sctp_shutdown_chunk_t {
          sctp_chunkhdr_t    chunk_hdr;
          sctp_shutdownhdr_t shutdown_hdr;
  } __attribute__ ((packed));
  
  /* RFC 2960.  Section 3.3.10 Operation Error (ERROR) (9) */
  
  typedef struct sctp_errhdr {

  	__be16 cause;
  	__be16 length;

  	__u8  variable[0];
  } __attribute__((packed)) sctp_errhdr_t;
  
  typedef struct sctp_operr_chunk {
          sctp_chunkhdr_t chunk_hdr;
  	sctp_errhdr_t   err_hdr;
  } __attribute__((packed)) sctp_operr_chunk_t;
  
  /* RFC 2960 3.3.10 - Operation Error
   *
   * Cause Code: 16 bits (unsigned integer)
   *
   *     Defines the type of error conditions being reported.
   *    Cause Code
   *     Value           Cause Code
   *     ---------      ----------------
   *      1              Invalid Stream Identifier
   *      2              Missing Mandatory Parameter
   *      3              Stale Cookie Error
   *      4              Out of Resource
   *      5              Unresolvable Address
   *      6              Unrecognized Chunk Type
   *      7              Invalid Mandatory Parameter
   *      8              Unrecognized Parameters
   *      9              No User Data
   *     10              Cookie Received While Shutting Down
   */
  typedef enum {
  
  	SCTP_ERROR_NO_ERROR	   = __constant_htons(0x00),
  	SCTP_ERROR_INV_STRM	   = __constant_htons(0x01),
  	SCTP_ERROR_MISS_PARAM 	   = __constant_htons(0x02),
  	SCTP_ERROR_STALE_COOKIE	   = __constant_htons(0x03),
  	SCTP_ERROR_NO_RESOURCE 	   = __constant_htons(0x04),
  	SCTP_ERROR_DNS_FAILED      = __constant_htons(0x05),
  	SCTP_ERROR_UNKNOWN_CHUNK   = __constant_htons(0x06),
  	SCTP_ERROR_INV_PARAM       = __constant_htons(0x07),
  	SCTP_ERROR_UNKNOWN_PARAM   = __constant_htons(0x08),
  	SCTP_ERROR_NO_DATA         = __constant_htons(0x09),
  	SCTP_ERROR_COOKIE_IN_SHUTDOWN = __constant_htons(0x0a),
  
  
  	/* SCTP Implementation Guide:
  	 *  11  Restart of an association with new addresses
  	 *  12  User Initiated Abort
  	 *  13  Protocol Violation
  	 */
  
  	SCTP_ERROR_RESTART         = __constant_htons(0x0b),
  	SCTP_ERROR_USER_ABORT      = __constant_htons(0x0c),
  	SCTP_ERROR_PROTO_VIOLATION = __constant_htons(0x0d),
  
  	/* ADDIP Section 3.3  New Error Causes
  	 *
  	 * Four new Error Causes are added to the SCTP Operational Errors,
  	 * primarily for use in the ASCONF-ACK chunk.
  	 *
  	 * Value          Cause Code
  	 * ---------      ----------------
  	 * 0x0100          Request to Delete Last Remaining IP Address.
  	 * 0x0101          Operation Refused Due to Resource Shortage.
  	 * 0x0102          Request to Delete Source IP Address.
  	 * 0x0103          Association Aborted due to illegal ASCONF-ACK
  	 * 0x0104          Request refused - no authorization.
  	 */
  	SCTP_ERROR_DEL_LAST_IP	= __constant_htons(0x0100),
  	SCTP_ERROR_RSRC_LOW	= __constant_htons(0x0101),
  	SCTP_ERROR_DEL_SRC_IP	= __constant_htons(0x0102),
  	SCTP_ERROR_ASCONF_ACK   = __constant_htons(0x0103),

  	SCTP_ERROR_REQ_REFUSED	= __constant_htons(0x0104),
  
  	/* AUTH Section 4.  New Error Cause
  	 *
  	 * This section defines a new error cause that will be sent if an AUTH
  	 * chunk is received with an unsupported HMAC identifier.
  	 * illustrates the new error cause.
  	 *
  	 * Cause Code      Error Cause Name
  	 * --------------------------------------------------------------
  	 * 0x0105          Unsupported HMAC Identifier
  	 */
  	 SCTP_ERROR_UNSUP_HMAC	= __constant_htons(0x0105)

  } sctp_error_t;
  
  
  
  /* RFC 2960.  Appendix A.  Explicit Congestion Notification.
   *   Explicit Congestion Notification Echo (ECNE) (12)
   */
  typedef struct sctp_ecnehdr {

  	__be32 lowest_tsn;

  } sctp_ecnehdr_t;
  
  typedef struct sctp_ecne_chunk {
  	sctp_chunkhdr_t chunk_hdr;
  	sctp_ecnehdr_t ence_hdr;
  } __attribute__((packed)) sctp_ecne_chunk_t;
  
  /* RFC 2960.  Appendix A.  Explicit Congestion Notification.
   *   Congestion Window Reduced (CWR) (13)
   */
  typedef struct sctp_cwrhdr {

  	__be32 lowest_tsn;

  } sctp_cwrhdr_t;
  
  typedef struct sctp_cwr_chunk {
  	sctp_chunkhdr_t chunk_hdr;
  	sctp_cwrhdr_t cwr_hdr;
  } __attribute__((packed)) sctp_cwr_chunk_t;
  
  /* PR-SCTP
   * 3.2 Forward Cumulative TSN Chunk Definition (FORWARD TSN)
   *
   * Forward Cumulative TSN chunk has the following format:
   *
   *        0                   1                   2                   3
   *        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *      |   Type = 192  |  Flags = 0x00 |        Length = Variable      |
   *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *      |                      New Cumulative TSN                       |
   *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *      |         Stream-1              |       Stream Sequence-1       |
   *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *      \                                                               /
   *      /                                                               \
   *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *      |         Stream-N              |       Stream Sequence-N       |
   *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *
   *      Chunk Flags:
   *
   *        Set to all zeros on transmit and ignored on receipt.
   *
   *      New Cumulative TSN: 32 bit u_int
   *
   *       This indicates the new cumulative TSN to the data receiver. Upon
   *       the reception of this value, the data receiver MUST consider
   *       any missing TSNs earlier than or equal to this value as received
   *       and stop reporting them as gaps in any subsequent SACKs.
   *
   *      Stream-N: 16 bit u_int
   *
   *       This field holds a stream number that was skipped by this
   *       FWD-TSN.
   *
   *      Stream Sequence-N: 16 bit u_int
   *       This field holds the sequence number associated with the stream
   *       that was skipped. The stream sequence field holds the largest stream
   *       sequence number in this stream being skipped.  The receiver of
   *       the FWD-TSN's can use the Stream-N and Stream Sequence-N fields
   *       to enable delivery of any stranded TSN's that remain on the stream
   *       re-ordering queues. This field MUST NOT report TSN's corresponding
   *       to DATA chunk that are marked as unordered. For ordered DATA
   *       chunks this field MUST be filled in.
   */
  struct sctp_fwdtsn_skip {

  	__be16 stream;
  	__be16 ssn;

  } __attribute__((packed));
  
  struct sctp_fwdtsn_hdr {

  	__be32 new_cum_tsn;

  	struct sctp_fwdtsn_skip skip[0];
  } __attribute((packed));
  
  struct sctp_fwdtsn_chunk {
  	struct sctp_chunkhdr chunk_hdr;
  	struct sctp_fwdtsn_hdr fwdtsn_hdr;
  } __attribute((packed));
  
  
  /* ADDIP
   * Section 3.1.1 Address Configuration Change Chunk (ASCONF)
   *
   * 	Serial Number: 32 bits (unsigned integer)
   *	This value represents a Serial Number for the ASCONF Chunk. The
   *	valid range of Serial Number is from 0 to 2^32-1.
   *	Serial Numbers wrap back to 0 after reaching 2^32 -1.
   *
   *	Address Parameter: 8 or 20 bytes (depending on type)
   *	The address is an address of the sender of the ASCONF chunk,
   *	the address MUST be considered part of the association by the
   *	peer endpoint. This field may be used by the receiver of the 
   *	ASCONF to help in finding the association. This parameter MUST
   *	be present in every ASCONF message i.e. it is a mandatory TLV
   *	parameter.
   *
   *	ASCONF Parameter: TLV format
   *	Each Address configuration change is represented by a TLV
   *	parameter as defined in Section 3.2. One or more requests may
   *	be present in an ASCONF Chunk.
   *
   * Section 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
   * 
   *	Serial Number: 32 bits (unsigned integer)
   *	This value represents the Serial Number for the received ASCONF
   *	Chunk that is acknowledged by this chunk. This value is copied
   *	from the received ASCONF Chunk. 
   *
   *	ASCONF Parameter Response: TLV format
   *	The ASCONF Parameter Response is used in the ASCONF-ACK to
   *	report status of ASCONF processing.
   */
  typedef struct sctp_addip_param {
  	sctp_paramhdr_t	param_hdr;

  	__be32		crr_id;

  } __attribute__((packed)) sctp_addip_param_t;
  
  typedef struct sctp_addiphdr {

  	__be32	serial;

  	__u8	params[0];
  } __attribute__((packed)) sctp_addiphdr_t;
  
  typedef struct sctp_addip_chunk {
  	sctp_chunkhdr_t chunk_hdr;
  	sctp_addiphdr_t addip_hdr;
  } __attribute__((packed)) sctp_addip_chunk_t;

  /* AUTH
   * Section 4.1  Authentication Chunk (AUTH)
   *
   *   This chunk is used to hold the result of the HMAC calculation.
   *
   *    0                   1                   2                   3
   *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *   | Type = 0x0F   |   Flags=0     |             Length            |
   *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *   |     Shared Key Identifier     |   HMAC Identifier             |
   *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *   |                                                               |
   *   \                             HMAC                              /
   *   /                                                               \
   *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *
   *   Type: 1 byte (unsigned integer)
   *   	This value MUST be set to 0x0F for  all AUTH-chunks.
   *
   *   Flags: 1 byte (unsigned integer)
   *	Set to zero on transmit and ignored on receipt.
   *
   *   Length: 2 bytes (unsigned integer)
   *   	This value holds the length of the HMAC in bytes plus 8.
   *
   *  Shared Key Identifier: 2 bytes (unsigned integer)
   *	This value describes which endpoint pair shared key is used.
   *
   *   HMAC Identifier: 2 bytes (unsigned integer)
   *   	This value describes which message digest is being used.  Table 2
   *	shows the currently defined values.
   *
   *    The following Table 2 shows the currently defined values for HMAC
   *       identifiers.
   *
   *	 +-----------------+--------------------------+
   *	 | HMAC Identifier | Message Digest Algorithm |
   *	 +-----------------+--------------------------+
   *	 | 0               | Reserved                 |
   *	 | 1               | SHA-1 defined in [8]     |
   *	 | 2               | Reserved                 |
   *	 | 3               | SHA-256 defined in [8]   |
   *	 +-----------------+--------------------------+
   *
   *
   *   HMAC: n bytes (unsigned integer) This hold the result of the HMAC
   *      calculation.
   */
  typedef struct sctp_authhdr {
  	__be16 shkey_id;
  	__be16 hmac_id;
  	__u8   hmac[0];
  } __attribute__((packed)) sctp_authhdr_t;
  
  typedef struct sctp_auth_chunk {
  	sctp_chunkhdr_t chunk_hdr;
  	sctp_authhdr_t auth_hdr;
  } __attribute__((packed)) sctp_auth_chunk_t;

  #endif /* __LINUX_SCTP_H__ */