/* SPDX-License-Identifier: GPL-2.0-or-later */
/* 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.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <linux-sctp@vger.kernel.org>
 *
 * 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.  */
#include <linux/skbuff.h>

#include <uapi/linux/sctp.h>

/* Section 3.1.  SCTP Common Header Format */
struct sctphdr {
        __be16 source;
        __be16 dest;
        __be32 vtag;
        __le32 checksum;
};

static inline struct sctphdr *sctp_hdr(const struct sk_buff *skb)
{
        return (struct sctphdr *)skb_transport_header(skb);
}

/* Section 3.2.  Chunk Field Descriptions. */
struct sctp_chunkhdr {
        __u8 type;
        __u8 flags;
        __be16 length;
};


/* 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.
 */
enum sctp_cid {
        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,

        /* sctp ndata 5.1. I-DATA */
        SCTP_CID_I_DATA                 = 0x40,

        /* 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_I_FWD_TSN              = 0xC2,
        SCTP_CID_ASCONF_ACK             = 0x80,
        SCTP_CID_RECONF                 = 0x82,
        SCTP_CID_PAD                    = 0x84,
}; /* 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.
 */
enum {
        SCTP_CID_ACTION_DISCARD     = 0x00,
        SCTP_CID_ACTION_DISCARD_ERR = 0x40,
        SCTP_CID_ACTION_SKIP        = 0x80,
        SCTP_CID_ACTION_SKIP_ERR    = 0xc0,
};

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.
 */

struct sctp_paramhdr {
        __be16 type;
        __be16 length;
};

enum sctp_param {

        /* RFC 2960 Section 3.3.5 */
        SCTP_PARAM_HEARTBEAT_INFO               = cpu_to_be16(1),
        /* RFC 2960 Section 3.3.2.1 */
        SCTP_PARAM_IPV4_ADDRESS                 = cpu_to_be16(5),
        SCTP_PARAM_IPV6_ADDRESS                 = cpu_to_be16(6),
        SCTP_PARAM_STATE_COOKIE                 = cpu_to_be16(7),
        SCTP_PARAM_UNRECOGNIZED_PARAMETERS      = cpu_to_be16(8),
        SCTP_PARAM_COOKIE_PRESERVATIVE          = cpu_to_be16(9),
        SCTP_PARAM_HOST_NAME_ADDRESS            = cpu_to_be16(11),
        SCTP_PARAM_SUPPORTED_ADDRESS_TYPES      = cpu_to_be16(12),
        SCTP_PARAM_ECN_CAPABLE                  = cpu_to_be16(0x8000),

        /* AUTH Extension Section 3 */
        SCTP_PARAM_RANDOM                       = cpu_to_be16(0x8002),
        SCTP_PARAM_CHUNKS                       = cpu_to_be16(0x8003),
        SCTP_PARAM_HMAC_ALGO                    = cpu_to_be16(0x8004),

        /* Add-IP: Supported Extensions, Section 4.2 */
        SCTP_PARAM_SUPPORTED_EXT        = cpu_to_be16(0x8008),

        /* PR-SCTP Sec 3.1 */
        SCTP_PARAM_FWD_TSN_SUPPORT      = cpu_to_be16(0xc000),

        /* Add-IP Extension. Section 3.2 */
        SCTP_PARAM_ADD_IP               = cpu_to_be16(0xc001),
        SCTP_PARAM_DEL_IP               = cpu_to_be16(0xc002),
        SCTP_PARAM_ERR_CAUSE            = cpu_to_be16(0xc003),
        SCTP_PARAM_SET_PRIMARY          = cpu_to_be16(0xc004),
        SCTP_PARAM_SUCCESS_REPORT       = cpu_to_be16(0xc005),
        SCTP_PARAM_ADAPTATION_LAYER_IND = cpu_to_be16(0xc006),

        /* RE-CONFIG. Section 4 */
        SCTP_PARAM_RESET_OUT_REQUEST            = cpu_to_be16(0x000d),
        SCTP_PARAM_RESET_IN_REQUEST             = cpu_to_be16(0x000e),
        SCTP_PARAM_RESET_TSN_REQUEST            = cpu_to_be16(0x000f),
        SCTP_PARAM_RESET_RESPONSE               = cpu_to_be16(0x0010),
        SCTP_PARAM_RESET_ADD_OUT_STREAMS        = cpu_to_be16(0x0011),
        SCTP_PARAM_RESET_ADD_IN_STREAMS         = cpu_to_be16(0x0012),
}; /* 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.
 *
 */
enum {
        SCTP_PARAM_ACTION_DISCARD     = cpu_to_be16(0x0000),
        SCTP_PARAM_ACTION_DISCARD_ERR = cpu_to_be16(0x4000),
        SCTP_PARAM_ACTION_SKIP        = cpu_to_be16(0x8000),
        SCTP_PARAM_ACTION_SKIP_ERR    = cpu_to_be16(0xc000),
};

enum { SCTP_PARAM_ACTION_MASK = cpu_to_be16(0xc000), };

/* RFC 2960 Section 3.3.1 Payload Data (DATA) (0) */

struct sctp_datahdr {
        __be32 tsn;
        __be16 stream;
        __be16 ssn;
        __u32 ppid;
        __u8  payload[];
};

struct sctp_data_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_datahdr data_hdr;
};

struct sctp_idatahdr {
        __be32 tsn;
        __be16 stream;
        __be16 reserved;
        __be32 mid;
        union {
                __u32 ppid;
                __be32 fsn;
        };
        __u8 payload[0];
};

struct sctp_idata_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_idatahdr data_hdr;
};

/* 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,
        SCTP_DATA_SACK_IMM      = 0x08,
};
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.
 */
struct sctp_inithdr {
        __be32 init_tag;
        __be32 a_rwnd;
        __be16 num_outbound_streams;
        __be16 num_inbound_streams;
        __be32 initial_tsn;
        __u8  params[];
};

struct sctp_init_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_inithdr init_hdr;
};


/* Section 3.3.2.1. IPv4 Address Parameter (5) */
struct sctp_ipv4addr_param {
        struct sctp_paramhdr param_hdr;
        struct in_addr addr;
};

/* Section 3.3.2.1. IPv6 Address Parameter (6) */
struct sctp_ipv6addr_param {
        struct sctp_paramhdr param_hdr;
        struct in6_addr addr;
};

/* Section 3.3.2.1 Cookie Preservative (9) */
struct sctp_cookie_preserve_param {
        struct sctp_paramhdr param_hdr;
        __be32 lifespan_increment;
};

/* Section 3.3.2.1 Host Name Address (11) */
struct sctp_hostname_param {
        struct sctp_paramhdr param_hdr;
        uint8_t hostname[];
};

/* Section 3.3.2.1 Supported Address Types (12) */
struct sctp_supported_addrs_param {
        struct sctp_paramhdr param_hdr;
        __be16 types[];
};

/* ADDIP Section 3.2.6 Adaptation Layer Indication */
struct sctp_adaptation_ind_param {
        struct sctp_paramhdr param_hdr;
        __be32 adaptation_ind;
};

/* ADDIP Section 4.2.7 Supported Extensions Parameter */
struct sctp_supported_ext_param {
        struct sctp_paramhdr param_hdr;
        __u8 chunks[];
};

/* AUTH Section 3.1 Random */
struct sctp_random_param {
        struct sctp_paramhdr param_hdr;
        __u8 random_val[];
};

/* AUTH Section 3.2 Chunk List */
struct sctp_chunks_param {
        struct sctp_paramhdr param_hdr;
        __u8 chunks[];
};

/* AUTH Section 3.3 HMAC Algorithm */
struct sctp_hmac_algo_param {
        struct sctp_paramhdr param_hdr;
        __be16 hmac_ids[];
};

/* 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.
 */
struct sctp_initack_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_inithdr init_hdr;
};

/* Section 3.3.3.1 State Cookie (7) */
struct sctp_cookie_param {
        struct sctp_paramhdr p;
        __u8 body[];
};

/* Section 3.3.3.1 Unrecognized Parameters (8) */
struct sctp_unrecognized_param {
        struct sctp_paramhdr param_hdr;
        struct sctp_paramhdr unrecognized;
};



/*
 * 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.
 */

struct sctp_gap_ack_block {
        __be16 start;
        __be16 end;
};

union sctp_sack_variable {
        struct sctp_gap_ack_block gab;
        __be32 dup;
};

struct sctp_sackhdr {
        __be32 cum_tsn_ack;
        __be32 a_rwnd;
        __be16 num_gap_ack_blocks;
        __be16 num_dup_tsns;
        union sctp_sack_variable variable[];
};

struct sctp_sack_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_sackhdr sack_hdr;
};


/* 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.
 */

struct sctp_heartbeathdr {
        struct sctp_paramhdr info;
};

struct sctp_heartbeat_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_heartbeathdr hb_hdr;
};


/* PAD chunk could be bundled with heartbeat chunk to probe pmtu */
struct sctp_pad_chunk {
        struct sctp_chunkhdr uh;
};


/* 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.
 */
struct sctp_abort_chunk {
        struct sctp_chunkhdr uh;
};


/* For the graceful shutdown we must carry the tag (in common header)
 * and the highest consecutive acking value.
 */
struct sctp_shutdownhdr {
        __be32 cum_tsn_ack;
};

struct sctp_shutdown_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_shutdownhdr shutdown_hdr;
};

/* RFC 2960.  Section 3.3.10 Operation Error (ERROR) (9) */

struct sctp_errhdr {
        __be16 cause;
        __be16 length;
        __u8  variable[];
};

struct sctp_operr_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_errhdr err_hdr;
};

/* 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
 */
enum sctp_error {

        SCTP_ERROR_NO_ERROR        = cpu_to_be16(0x00),
        SCTP_ERROR_INV_STRM        = cpu_to_be16(0x01),
        SCTP_ERROR_MISS_PARAM      = cpu_to_be16(0x02),
        SCTP_ERROR_STALE_COOKIE    = cpu_to_be16(0x03),
        SCTP_ERROR_NO_RESOURCE     = cpu_to_be16(0x04),
        SCTP_ERROR_DNS_FAILED      = cpu_to_be16(0x05),
        SCTP_ERROR_UNKNOWN_CHUNK   = cpu_to_be16(0x06),
        SCTP_ERROR_INV_PARAM       = cpu_to_be16(0x07),
        SCTP_ERROR_UNKNOWN_PARAM   = cpu_to_be16(0x08),
        SCTP_ERROR_NO_DATA         = cpu_to_be16(0x09),
        SCTP_ERROR_COOKIE_IN_SHUTDOWN = cpu_to_be16(0x0a),


        /* SCTP Implementation Guide:
         *  11  Restart of an association with new addresses
         *  12  User Initiated Abort
         *  13  Protocol Violation
         *  14  Restart of an Association with New Encapsulation Port
         */

        SCTP_ERROR_RESTART         = cpu_to_be16(0x0b),
        SCTP_ERROR_USER_ABORT      = cpu_to_be16(0x0c),
        SCTP_ERROR_PROTO_VIOLATION = cpu_to_be16(0x0d),
        SCTP_ERROR_NEW_ENCAP_PORT  = cpu_to_be16(0x0e),

        /* 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
         * ---------      ----------------
         * 0x00A0          Request to Delete Last Remaining IP Address.
         * 0x00A1          Operation Refused Due to Resource Shortage.
         * 0x00A2          Request to Delete Source IP Address.
         * 0x00A3          Association Aborted due to illegal ASCONF-ACK
         * 0x00A4          Request refused - no authorization.
         */
        SCTP_ERROR_DEL_LAST_IP  = cpu_to_be16(0x00A0),
        SCTP_ERROR_RSRC_LOW     = cpu_to_be16(0x00A1),
        SCTP_ERROR_DEL_SRC_IP   = cpu_to_be16(0x00A2),
        SCTP_ERROR_ASCONF_ACK   = cpu_to_be16(0x00A3),
        SCTP_ERROR_REQ_REFUSED  = cpu_to_be16(0x00A4),

        /* 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  = cpu_to_be16(0x0105)
};



/* RFC 2960.  Appendix A.  Explicit Congestion Notification.
 *   Explicit Congestion Notification Echo (ECNE) (12)
 */
struct sctp_ecnehdr {
        __be32 lowest_tsn;
};

struct sctp_ecne_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_ecnehdr ence_hdr;
};

/* RFC 2960.  Appendix A.  Explicit Congestion Notification.
 *   Congestion Window Reduced (CWR) (13)
 */
struct sctp_cwrhdr {
        __be32 lowest_tsn;
};

/* 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;
};

struct sctp_fwdtsn_hdr {
        __be32 new_cum_tsn;
        struct sctp_fwdtsn_skip skip[];
};

struct sctp_fwdtsn_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_fwdtsn_hdr fwdtsn_hdr;
};

struct sctp_ifwdtsn_skip {
        __be16 stream;
        __u8 reserved;
        __u8 flags;
        __be32 mid;
};

struct sctp_ifwdtsn_hdr {
        __be32 new_cum_tsn;
        struct sctp_ifwdtsn_skip skip[];
};

struct sctp_ifwdtsn_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_ifwdtsn_hdr fwdtsn_hdr;
};

/* 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.
 */
struct sctp_addip_param {
        struct sctp_paramhdr param_hdr;
        __be32 crr_id;
};

struct sctp_addiphdr {
        __be32  serial;
        __u8    params[];
};

struct sctp_addip_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_addiphdr addip_hdr;
};

/* 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.
 */
struct sctp_authhdr {
        __be16 shkey_id;
        __be16 hmac_id;
        __u8   hmac[];
};

struct sctp_auth_chunk {
        struct sctp_chunkhdr chunk_hdr;
        struct sctp_authhdr auth_hdr;
};

struct sctp_infox {
        struct sctp_info *sctpinfo;
        struct sctp_association *asoc;
};

struct sctp_reconf_chunk {
        struct sctp_chunkhdr chunk_hdr;
        __u8 params[];
};

struct sctp_strreset_outreq {
        struct sctp_paramhdr param_hdr;
        __be32 request_seq;
        __be32 response_seq;
        __be32 send_reset_at_tsn;
        __be16 list_of_streams[];
};

struct sctp_strreset_inreq {
        struct sctp_paramhdr param_hdr;
        __be32 request_seq;
        __be16 list_of_streams[];
};

struct sctp_strreset_tsnreq {
        struct sctp_paramhdr param_hdr;
        __be32 request_seq;
};

struct sctp_strreset_addstrm {
        struct sctp_paramhdr param_hdr;
        __be32 request_seq;
        __be16 number_of_streams;
        __be16 reserved;
};

enum {
        SCTP_STRRESET_NOTHING_TO_DO     = 0x00,
        SCTP_STRRESET_PERFORMED         = 0x01,
        SCTP_STRRESET_DENIED            = 0x02,
        SCTP_STRRESET_ERR_WRONG_SSN     = 0x03,
        SCTP_STRRESET_ERR_IN_PROGRESS   = 0x04,
        SCTP_STRRESET_ERR_BAD_SEQNO     = 0x05,
        SCTP_STRRESET_IN_PROGRESS       = 0x06,
};

struct sctp_strreset_resp {
        struct sctp_paramhdr param_hdr;
        __be32 response_seq;
        __be32 result;
};

struct sctp_strreset_resptsn {
        struct sctp_paramhdr param_hdr;
        __be32 response_seq;
        __be32 result;
        __be32 senders_next_tsn;
        __be32 receivers_next_tsn;
};

enum {
        SCTP_DSCP_SET_MASK = 0x1,
        SCTP_DSCP_VAL_MASK = 0xfc,
        SCTP_FLOWLABEL_SET_MASK = 0x100000,
        SCTP_FLOWLABEL_VAL_MASK = 0xfffff
};

/* UDP Encapsulation
 * draft-tuexen-tsvwg-sctp-udp-encaps-cons-03.html#section-4-4
 *
 *   The error cause indicating an "Restart of an Association with
 *   New Encapsulation Port"
 *
 * 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |        Cause Code = 14        |       Cause Length = 8        |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |   Current Encapsulation Port  |     New Encapsulation Port    |
 * +-------------------------------+-------------------------------+
 */
struct sctp_new_encap_port_hdr {
        __be16 cur_port;
        __be16 new_port;
};

#endif /* __LINUX_SCTP_H__ */