constants.h

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/* 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 <[email protected]>
 *
 * Or submit a bug report through the following website:
 *    http://www.sf.net/projects/lksctp
 *
 * Written or modified by:
 *   La Monte H.P. Yarroll <[email protected]>
 *   Karl Knutson          <[email protected]>
 *   Randall Stewart       <[email protected]>
 *   Ken Morneau           <[email protected]>
 *   Qiaobing Xie          <[email protected]>
 *   Xingang Guo           <[email protected]>
 *   Sridhar Samudrala     <[email protected]>
 *   Daisy Chang           <[email protected]>
 *
 * 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_PF,
} 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__ */