/* SCTP kernel implementation

   * (C) Copyright IBM Corp. 2001, 2004
   * Copyright (c) 1999-2000 Cisco, Inc.
   * Copyright (c) 1999-2001 Motorola, Inc.
   * Copyright (c) 2001 Intel Corp.
   *

   * This file is part of the SCTP kernel implementation

   *

   * 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-developers@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>
   *   Randall Stewart       <randall@stewart.chicago.il.us>
   *   Ken Morneau           <kmorneau@cisco.com>
   *   Qiaobing Xie          <qxie1@motorola.com>
   *   Xingang Guo           <xingang.guo@intel.com>
   *   Sridhar Samudrala     <samudrala@us.ibm.com>
   *   Daisy Chang           <daisyc@us.ibm.com>
   *
   * Any bugs reported given to us we will try to fix... any fixes shared will
   * be incorporated into the next SCTP release.
   */
  
  #ifndef __sctp_constants_h__
  #define __sctp_constants_h__

  #include <linux/sctp.h>
  #include <linux/ipv6.h> /* For ipv6hdr. */
  #include <net/sctp/user.h>

  #include <net/tcp_states.h>  /* For TCP states used in sctp_sock_state_t */

  
  /* Value used for stream negotiation. */
  enum { SCTP_MAX_STREAM = 0xffff };
  enum { SCTP_DEFAULT_OUTSTREAMS = 10 };
  enum { SCTP_DEFAULT_INSTREAMS = SCTP_MAX_STREAM };
  
  /* Since CIDs are sparse, we need all four of the following
   * symbols.  CIDs are dense through SCTP_CID_BASE_MAX.
   */
  #define SCTP_CID_BASE_MAX		SCTP_CID_SHUTDOWN_COMPLETE

  
  #define SCTP_NUM_BASE_CHUNK_TYPES	(SCTP_CID_BASE_MAX + 1)

  
  #define SCTP_NUM_ADDIP_CHUNK_TYPES	2
  
  #define SCTP_NUM_PRSCTP_CHUNK_TYPES	1

  #define SCTP_NUM_AUTH_CHUNK_TYPES	1
  
  #define SCTP_NUM_CHUNK_TYPES		(SCTP_NUM_BASE_CHUNK_TYPES + \
  					 SCTP_NUM_ADDIP_CHUNK_TYPES +\
  					 SCTP_NUM_PRSCTP_CHUNK_TYPES +\
  					 SCTP_NUM_AUTH_CHUNK_TYPES)

  /* These are the different flavours of event.  */
  typedef enum {
  
  	SCTP_EVENT_T_CHUNK = 1,
  	SCTP_EVENT_T_TIMEOUT,
  	SCTP_EVENT_T_OTHER,
  	SCTP_EVENT_T_PRIMITIVE
  
  } sctp_event_t;

  /* As a convenience for the state machine, we append SCTP_EVENT_* and
   * SCTP_ULP_* to the list of possible chunks.
   */
  
  typedef enum {
  	SCTP_EVENT_TIMEOUT_NONE = 0,
  	SCTP_EVENT_TIMEOUT_T1_COOKIE,
  	SCTP_EVENT_TIMEOUT_T1_INIT,
  	SCTP_EVENT_TIMEOUT_T2_SHUTDOWN,
  	SCTP_EVENT_TIMEOUT_T3_RTX,
  	SCTP_EVENT_TIMEOUT_T4_RTO,
  	SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD,
  	SCTP_EVENT_TIMEOUT_HEARTBEAT,
  	SCTP_EVENT_TIMEOUT_SACK,
  	SCTP_EVENT_TIMEOUT_AUTOCLOSE,
  } sctp_event_timeout_t;
  
  #define SCTP_EVENT_TIMEOUT_MAX		SCTP_EVENT_TIMEOUT_AUTOCLOSE
  #define SCTP_NUM_TIMEOUT_TYPES		(SCTP_EVENT_TIMEOUT_MAX + 1)
  
  typedef enum {
  	SCTP_EVENT_NO_PENDING_TSN = 0,
  	SCTP_EVENT_ICMP_PROTO_UNREACH,
  } sctp_event_other_t;
  
  #define SCTP_EVENT_OTHER_MAX		SCTP_EVENT_ICMP_PROTO_UNREACH
  #define SCTP_NUM_OTHER_TYPES		(SCTP_EVENT_OTHER_MAX + 1)
  
  /* These are primitive requests from the ULP.  */
  typedef enum {
  	SCTP_PRIMITIVE_ASSOCIATE = 0,
  	SCTP_PRIMITIVE_SHUTDOWN,
  	SCTP_PRIMITIVE_ABORT,
  	SCTP_PRIMITIVE_SEND,
  	SCTP_PRIMITIVE_REQUESTHEARTBEAT,
  	SCTP_PRIMITIVE_ASCONF,
  } sctp_event_primitive_t;
  
  #define SCTP_EVENT_PRIMITIVE_MAX	SCTP_PRIMITIVE_ASCONF
  #define SCTP_NUM_PRIMITIVE_TYPES	(SCTP_EVENT_PRIMITIVE_MAX + 1)
  
  /* We define here a utility type for manipulating subtypes.
   * The subtype constructors all work like this:
   *
   * 	sctp_subtype_t foo = SCTP_ST_CHUNK(SCTP_CID_INIT);
   */
  
  typedef union {
  	sctp_cid_t chunk;
  	sctp_event_timeout_t timeout;
  	sctp_event_other_t other;
  	sctp_event_primitive_t primitive;
  } sctp_subtype_t;
  
  #define SCTP_SUBTYPE_CONSTRUCTOR(_name, _type, _elt) \
  static inline sctp_subtype_t	\
  SCTP_ST_## _name (_type _arg)		\
  { sctp_subtype_t _retval; _retval._elt = _arg; return _retval; }
  
  SCTP_SUBTYPE_CONSTRUCTOR(CHUNK,		sctp_cid_t,		chunk)
  SCTP_SUBTYPE_CONSTRUCTOR(TIMEOUT,	sctp_event_timeout_t,	timeout)
  SCTP_SUBTYPE_CONSTRUCTOR(OTHER,		sctp_event_other_t,	other)
  SCTP_SUBTYPE_CONSTRUCTOR(PRIMITIVE,	sctp_event_primitive_t,	primitive)

  #define sctp_chunk_is_data(a) (a->chunk_hdr->type == SCTP_CID_DATA)
  
  /* Calculate the actual data size in a data chunk */
  #define SCTP_DATA_SNDSIZE(c) ((int)((unsigned long)(c->chunk_end)\
  		       		- (unsigned long)(c->chunk_hdr)\
  				- sizeof(sctp_data_chunk_t)))

  /* Internal error codes */
  typedef enum {
  
  	SCTP_IERROR_NO_ERROR	        = 0,
  	SCTP_IERROR_BASE		= 1000,
  	SCTP_IERROR_NO_COOKIE,
  	SCTP_IERROR_BAD_SIG,
  	SCTP_IERROR_STALE_COOKIE,
  	SCTP_IERROR_NOMEM,
  	SCTP_IERROR_MALFORMED,
  	SCTP_IERROR_BAD_TAG,
  	SCTP_IERROR_BIG_GAP,
  	SCTP_IERROR_DUP_TSN,
  	SCTP_IERROR_HIGH_TSN,
  	SCTP_IERROR_IGNORE_TSN,
  	SCTP_IERROR_NO_DATA,
  	SCTP_IERROR_BAD_STREAM,
  	SCTP_IERROR_BAD_PORTS,

  	SCTP_IERROR_AUTH_BAD_HMAC,
  	SCTP_IERROR_AUTH_BAD_KEYID,
  	SCTP_IERROR_PROTO_VIOLATION,

  	SCTP_IERROR_ERROR,
  	SCTP_IERROR_ABORT,

  } sctp_ierror_t;
  
  
  
  /* SCTP state defines for internal state machine */
  typedef enum {

  	SCTP_STATE_CLOSED		= 0,
  	SCTP_STATE_COOKIE_WAIT		= 1,
  	SCTP_STATE_COOKIE_ECHOED	= 2,
  	SCTP_STATE_ESTABLISHED		= 3,
  	SCTP_STATE_SHUTDOWN_PENDING	= 4,
  	SCTP_STATE_SHUTDOWN_SENT	= 5,
  	SCTP_STATE_SHUTDOWN_RECEIVED	= 6,
  	SCTP_STATE_SHUTDOWN_ACK_SENT	= 7,

  
  } sctp_state_t;
  
  #define SCTP_STATE_MAX			SCTP_STATE_SHUTDOWN_ACK_SENT
  #define SCTP_STATE_NUM_STATES		(SCTP_STATE_MAX + 1)
  
  /* These are values for sk->state.
   * For a UDP-style SCTP socket, the states are defined as follows
   * - A socket in SCTP_SS_CLOSED state indicates that it is not willing to
   *   accept new associations, but it can initiate the creation of new ones.
   * - A socket in SCTP_SS_LISTENING state indicates that it is willing to
   *   accept new  associations and can initiate the creation of new ones.
   * - A socket in SCTP_SS_ESTABLISHED state indicates that it is a peeled off
   *   socket with one association.
   * For a TCP-style SCTP socket, the states are defined as follows
   * - A socket in SCTP_SS_CLOSED state indicates that it is not willing to
   *   accept new associations, but it can initiate the creation of new ones.
   * - A socket in SCTP_SS_LISTENING state indicates that it is willing to
   *   accept new associations, but cannot initiate the creation of new ones.
   * - A socket in SCTP_SS_ESTABLISHED state indicates that it has a single 
   *   association.
   */
  typedef enum {
  	SCTP_SS_CLOSED         = TCP_CLOSE,
  	SCTP_SS_LISTENING      = TCP_LISTEN,
  	SCTP_SS_ESTABLISHING   = TCP_SYN_SENT,
  	SCTP_SS_ESTABLISHED    = TCP_ESTABLISHED,

  	SCTP_SS_CLOSING        = TCP_CLOSING,

  } sctp_sock_state_t;
  
  /* These functions map various type to printable names.  */
  const char *sctp_cname(const sctp_subtype_t);	/* chunk types */
  const char *sctp_oname(const sctp_subtype_t);	/* other events */
  const char *sctp_tname(const sctp_subtype_t);	/* timeouts */
  const char *sctp_pname(const sctp_subtype_t);	/* primitives */
  
  /* This is a table of printable names of sctp_state_t's.  */

  extern const char *const sctp_state_tbl[];
  extern const char *const sctp_evttype_tbl[];
  extern const char *const sctp_status_tbl[];

  
  /* Maximum chunk length considering padding requirements. */
  enum { SCTP_MAX_CHUNK_LEN = ((1<<16) - sizeof(__u32)) };
  
  /* Encourage Cookie-Echo bundling by pre-fragmenting chunks a little
   * harder (until reaching ESTABLISHED state).
   */
  enum { SCTP_ARBITRARY_COOKIE_ECHO_LEN = 200 };
  
  /* Guess at how big to make the TSN mapping array.
   * We guarantee that we can handle at least this big a gap between the
   * cumulative ACK and the highest TSN.  In practice, we can often
   * handle up to twice this value.
   *
   * NEVER make this more than 32767 (2^15-1).  The Gap Ack Blocks in a
   * SACK (see  section 3.3.4) are only 16 bits, so 2*SCTP_TSN_MAP_SIZE
   * must be less than 65535 (2^16 - 1), or we will have overflow
   * problems creating SACK's.
   */

  #define SCTP_TSN_MAP_INITIAL BITS_PER_LONG
  #define SCTP_TSN_MAP_INCREMENT SCTP_TSN_MAP_INITIAL
  #define SCTP_TSN_MAP_SIZE 4096

  
  /* We will not record more than this many duplicate TSNs between two
   * SACKs.  The minimum PMTU is 576.  Remove all the headers and there
   * is enough room for 131 duplicate reports.  Round down to the
   * nearest power of 2.
   */
  enum { SCTP_MIN_PMTU = 576 };
  enum { SCTP_MAX_DUP_TSNS = 16 };
  enum { SCTP_MAX_GABS = 16 };

  /* Heartbeat interval - 30 secs */

  #define SCTP_DEFAULT_TIMEOUT_HEARTBEAT	(30*1000)

  /* Delayed sack timer - 200ms */

  #define SCTP_DEFAULT_TIMEOUT_SACK	(200)

  
  /* RTO.Initial              - 3  seconds
   * RTO.Min                  - 1  second
   * RTO.Max                  - 60 seconds
   * RTO.Alpha                - 1/8
   * RTO.Beta                 - 1/4
   */

  #define SCTP_RTO_INITIAL	(3 * 1000)
  #define SCTP_RTO_MIN		(1 * 1000)
  #define SCTP_RTO_MAX		(60 * 1000)

  
  #define SCTP_RTO_ALPHA          3   /* 1/8 when converted to right shifts. */
  #define SCTP_RTO_BETA           2   /* 1/4 when converted to right shifts. */
  
  /* Maximum number of new data packets that can be sent in a burst.  */

  #define SCTP_DEFAULT_MAX_BURST		4

  
  #define SCTP_CLOCK_GRANULARITY	1	/* 1 jiffy */

  #define SCTP_DEFAULT_COOKIE_LIFE	(60 * 1000) /* 60 seconds */

  
  #define SCTP_DEFAULT_MINWINDOW	1500	/* default minimum rwnd size */
  #define SCTP_DEFAULT_MAXWINDOW	65535	/* default rwnd size */

  #define SCTP_DEFAULT_RWND_SHIFT  4	/* by default, update on 1/16 of
  					 * rcvbuf, which is 1/8 of initial
  					 * window
  					 */

  #define SCTP_DEFAULT_MAXSEGMENT 1500	/* MTU size, this is the limit
                                           * to which we will raise the P-MTU.
  					 */
  #define SCTP_DEFAULT_MINSEGMENT 512	/* MTU size ... if no mtu disc */
  #define SCTP_HOW_MANY_SECRETS 2		/* How many secrets I keep */

  #define SCTP_SECRET_SIZE 32		/* Number of octets in a 256 bits. */
  
  #define SCTP_SIGNATURE_SIZE 20	        /* size of a SLA-1 signature */
  
  #define SCTP_COOKIE_MULTIPLE 32 /* Pad out our cookie to make our hash
  				 * functions simpler to write.
  				 */
  
  #if defined (CONFIG_SCTP_HMAC_MD5)

  #define SCTP_COOKIE_HMAC_ALG "hmac(md5)"

  #elif defined (CONFIG_SCTP_HMAC_SHA1)

  #define SCTP_COOKIE_HMAC_ALG "hmac(sha1)"

  #else
  #define SCTP_COOKIE_HMAC_ALG NULL
  #endif
  
  /* These return values describe the success or failure of a number of
   * routines which form the lower interface to SCTP_outqueue.
   */
  typedef enum {
  	SCTP_XMIT_OK,
  	SCTP_XMIT_PMTU_FULL,
  	SCTP_XMIT_RWND_FULL,
  	SCTP_XMIT_NAGLE_DELAY,
  } sctp_xmit_t;
  
  /* These are the commands for manipulating transports.  */
  typedef enum {
  	SCTP_TRANSPORT_UP,
  	SCTP_TRANSPORT_DOWN,
  } sctp_transport_cmd_t;
  
  /* These are the address scopes defined mainly for IPv4 addresses
   * based on draft of SCTP IPv4 scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
   * These scopes are hopefully generic enough to be used on scoping both
   * IPv4 and IPv6 addresses in SCTP.
   * At this point, the IPv6 scopes will be mapped to these internal scopes
   * as much as possible.
   */
  typedef enum {
  	SCTP_SCOPE_GLOBAL,		/* IPv4 global addresses */
  	SCTP_SCOPE_PRIVATE,		/* IPv4 private addresses */
  	SCTP_SCOPE_LINK,		/* IPv4 link local address */
  	SCTP_SCOPE_LOOPBACK,		/* IPv4 loopback address */
  	SCTP_SCOPE_UNUSABLE,		/* IPv4 unusable addresses */
  } sctp_scope_t;

  typedef enum {
  	SCTP_SCOPE_POLICY_DISABLE,	/* Disable IPv4 address scoping */
  	SCTP_SCOPE_POLICY_ENABLE,	/* Enable IPv4 address scoping */
  	SCTP_SCOPE_POLICY_PRIVATE,	/* Follow draft but allow IPv4 private addresses */
  	SCTP_SCOPE_POLICY_LINK,		/* Follow draft but allow IPv4 link local addresses */
  } sctp_scope_policy_t;

  /* Based on IPv4 scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>,
   * SCTP IPv4 unusable addresses: 0.0.0.0/8, 224.0.0.0/4, 198.18.0.0/24,
   * 192.88.99.0/24.
   * Also, RFC 8.4, non-unicast addresses are not considered valid SCTP
   * addresses.
   */

  #define IS_IPV4_UNUSABLE_ADDRESS(a)	    \
  	((htonl(INADDR_BROADCAST) == a) ||  \
  	 ipv4_is_multicast(a) ||	    \
  	 ipv4_is_zeronet(a) ||		    \
  	 ipv4_is_test_198(a) ||		    \
  	 ipv4_is_anycast_6to4(a))

  
  /* Flags used for the bind address copy functions.  */
  #define SCTP_ADDR6_ALLOWED	0x00000001	/* IPv6 address is allowed by
  						   local sock family */
  #define SCTP_ADDR4_PEERSUPP	0x00000002	/* IPv4 address is supported by
  						   peer */
  #define SCTP_ADDR6_PEERSUPP	0x00000004	/* IPv6 address is supported by
  						   peer */
  
  /* Reasons to retransmit. */
  typedef enum {
  	SCTP_RTXR_T3_RTX,
  	SCTP_RTXR_FAST_RTX,
  	SCTP_RTXR_PMTUD,

  	SCTP_RTXR_T1_RTX,

  } sctp_retransmit_reason_t;
  
  /* Reasons to lower cwnd. */
  typedef enum {
  	SCTP_LOWER_CWND_T3_RTX,
  	SCTP_LOWER_CWND_FAST_RTX,
  	SCTP_LOWER_CWND_ECNE,
  	SCTP_LOWER_CWND_INACTIVE,
  } sctp_lower_cwnd_t;

  
  /* SCTP-AUTH Necessary constants */
  
  /* SCTP-AUTH, Section 3.3
   *
   *  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]   |
   *  +-----------------+--------------------------+
   */
  enum {
  	SCTP_AUTH_HMAC_ID_RESERVED_0,
  	SCTP_AUTH_HMAC_ID_SHA1,
  	SCTP_AUTH_HMAC_ID_RESERVED_2,

  #if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE)
  	SCTP_AUTH_HMAC_ID_SHA256,
  #endif
  	__SCTP_AUTH_HMAC_MAX

  };

  #define SCTP_AUTH_HMAC_ID_MAX	__SCTP_AUTH_HMAC_MAX - 1
  #define SCTP_AUTH_NUM_HMACS 	__SCTP_AUTH_HMAC_MAX

  #define SCTP_SHA1_SIG_SIZE 20
  #define SCTP_SHA256_SIG_SIZE 32
  
  /*  SCTP-AUTH, Section 3.2
   *     The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH chunks
   *     MUST NOT be listed in the CHUNKS parameter
   */
  #define SCTP_NUM_NOAUTH_CHUNKS	4
  #define SCTP_AUTH_MAX_CHUNKS	(SCTP_NUM_CHUNK_TYPES - SCTP_NUM_NOAUTH_CHUNKS)
  
  /* SCTP-AUTH Section 6.1
   * The RANDOM parameter MUST contain a 32 byte random number.
   */
  #define SCTP_AUTH_RANDOM_LENGTH 32

  #endif /* __sctp_constants_h__ */