structs.h

 * packets (it calls (*output_handler)()).
 *
 * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
 * and 8.2 of the v13 draft.
 *
 * It handles retransmissions.	The connection to the timeout portion
 * of the state machine is through sctp_..._timeout() and timeout_handler.
 *
 * If you feed it SACKs, it will eat them.
 *
 * If you give it big chunks, it will fragment them.
 *
 * It assigns TSN's to data chunks.  This happens at the last possible
 * instant before transmission.
 *
 * When free()'d, it empties itself out via output_handler().
 */
struct sctp_outq {
	struct sctp_association *asoc;

	/* Data pending that has never been transmitted.  */
	struct list_head out_chunk_list;

	unsigned int out_qlen;	/* Total length of queued data chunks. */

	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
	unsigned int error;

	/* These are control chunks we want to send.  */
	struct list_head control_chunk_list;

	/* These are chunks that have been sacked but are above the
	 * CTSN, or cumulative tsn ack point.
	 */
	struct list_head sacked;

	/* Put chunks on this list to schedule them for
	 * retransmission.
	 */
	struct list_head retransmit;

	/* Put chunks on this list to save them for FWD TSN processing as
	 * they were abandoned.
	 */
	struct list_head abandoned;

	/* How many unackd bytes do we have in-flight?	*/
	__u32 outstanding_bytes;

	/* Are we doing fast-rtx on this queue */
	char fast_rtx;

	/* Corked? */
	char cork;

	/* Is this structure empty?  */
	char empty;
};

void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
void sctp_outq_teardown(struct sctp_outq *);
void sctp_outq_free(struct sctp_outq*);
int sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk);
int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
int sctp_outq_is_empty(const struct sctp_outq *);
void sctp_outq_restart(struct sctp_outq *);

void sctp_retransmit(struct sctp_outq *, struct sctp_transport *,
		     sctp_retransmit_reason_t);
void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
int sctp_outq_uncork(struct sctp_outq *);
/* Uncork and flush an outqueue.  */
static inline void sctp_outq_cork(struct sctp_outq *q)
{
	q->cork = 1;
}

/* These bind address data fields common between endpoints and associations */
struct sctp_bind_addr {

	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
	 *
	 * SCTP Port:	The local SCTP port number the endpoint is
	 *		bound to.
	 */
	__u16 port;

	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
	 *
	 * Address List: The list of IP addresses that this instance
	 *	has bound.  This information is passed to one's
	 *	peer(s) in INIT and INIT ACK chunks.
	 */
	struct list_head address_list;
};

void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
void sctp_bind_addr_free(struct sctp_bind_addr *);
int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
			const struct sctp_bind_addr *src,
			sctp_scope_t scope, gfp_t gfp,
			int flags);
int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
			const struct sctp_bind_addr *src,
			gfp_t gfp);
int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
		       __u8 addr_state, gfp_t gfp);
int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
			 struct sctp_sock *);
int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
			 struct sctp_sock *, struct sctp_sock *);
int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
			 const union sctp_addr *addr);
union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
					const union sctp_addr	*addrs,
					int			addrcnt,
					struct sctp_sock	*opt);
union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
					 int *addrs_len,
					 gfp_t gfp);
int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
			   __u16 port, gfp_t gfp);

sctp_scope_t sctp_scope(const union sctp_addr *);
int sctp_in_scope(struct net *net, const union sctp_addr *addr, const sctp_scope_t scope);
int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
int sctp_addr_is_valid(const union sctp_addr *addr);
int sctp_is_ep_boundall(struct sock *sk);


/* What type of endpoint?  */
typedef enum {
	SCTP_EP_TYPE_SOCKET,
	SCTP_EP_TYPE_ASSOCIATION,
} sctp_endpoint_type_t;

/*
 * A common base class to bridge the implmentation view of a
 * socket (usually listening) endpoint versus an association's
 * local endpoint.
 * This common structure is useful for several purposes:
 *   1) Common interface for lookup routines.
 *	a) Subfunctions work for either endpoint or association
 *	b) Single interface to lookup allows hiding the lookup lock rather
 *	   than acquiring it externally.
 *   2) Common interface for the inbound chunk handling/state machine.
 *   3) Common object handling routines for reference counting, etc.
 *   4) Disentangle association lookup from endpoint lookup, where we
 *	do not have to find our endpoint to find our association.
 *
 */

struct sctp_ep_common {
	/* Fields to help us manage our entries in the hash tables. */
	struct hlist_node node;
	int hashent;

	/* Runtime type information.  What kind of endpoint is this? */
	sctp_endpoint_type_t type;

	/* Some fields to help us manage this object.
	 *   refcnt   - Reference count access to this object.
	 *   dead     - Do not attempt to use this object.
	 */
	atomic_t    refcnt;
	bool	    dead;

	/* What socket does this endpoint belong to?  */
	struct sock *sk;

	/* This is where we receive inbound chunks.  */
	struct sctp_inq	  inqueue;

	/* This substructure includes the defining parameters of the
	 * endpoint:
	 * bind_addr.port is our shared port number.
	 * bind_addr.address_list is our set of local IP addresses.
	 */
	struct sctp_bind_addr bind_addr;
};


/* RFC Section 1.4 Key Terms
 *
 * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
 *   multi-homed host, an SCTP endpoint is represented to its peers as a
 *   combination of a set of eligible destination transport addresses to
 *   which SCTP packets can be sent and a set of eligible source
 *   transport addresses from which SCTP packets can be received.
 *   All transport addresses used by an SCTP endpoint must use the
 *   same port number, but can use multiple IP addresses. A transport
 *   address used by an SCTP endpoint must not be used by another
 *   SCTP endpoint. In other words, a transport address is unique
 *   to an SCTP endpoint.
 *
 * From an implementation perspective, each socket has one of these.
 * A TCP-style socket will have exactly one association on one of
 * these.  An UDP-style socket will have multiple associations hanging
 * off one of these.
 */

struct sctp_endpoint {
	/* Common substructure for endpoint and association. */
	struct sctp_ep_common base;

	/* Associations: A list of current associations and mappings
	 *	      to the data consumers for each association. This
	 *	      may be in the form of a hash table or other
	 *	      implementation dependent structure. The data
	 *	      consumers may be process identification
	 *	      information such as file descriptors, named pipe
	 *	      pointer, or table pointers dependent on how SCTP
	 *	      is implemented.
	 */
	/* This is really a list of struct sctp_association entries. */
	struct list_head asocs;

	/* Secret Key: A secret key used by this endpoint to compute
	 *	      the MAC.	This SHOULD be a cryptographic quality
	 *	      random number with a sufficient length.
	 *	      Discussion in [RFC1750] can be helpful in
	 *	      selection of the key.
	 */
	__u8 secret_key[SCTP_SECRET_SIZE];

 	/* digest:  This is a digest of the sctp cookie.  This field is
 	 * 	    only used on the receive path when we try to validate
 	 * 	    that the cookie has not been tampered with.  We put
 	 * 	    this here so we pre-allocate this once and can re-use
 	 * 	    on every receive.
 	 */
 	__u8 *digest;
 
	/* sendbuf acct. policy.	*/
	__u32 sndbuf_policy;

	/* rcvbuf acct. policy.	*/
	__u32 rcvbuf_policy;

	/* SCTP AUTH: array of the HMACs that will be allocated
	 * we need this per association so that we don't serialize
	 */
	struct crypto_hash **auth_hmacs;

	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
	 struct sctp_hmac_algo_param *auth_hmacs_list;

	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
	struct sctp_chunks_param *auth_chunk_list;

	/* SCTP-AUTH: endpoint shared keys */
	struct list_head endpoint_shared_keys;
	__u16 active_key_id;
};

/* Recover the outter endpoint structure. */
static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
{
	struct sctp_endpoint *ep;

	ep = container_of(base, struct sctp_endpoint, base);
	return ep;
}

/* These are function signatures for manipulating endpoints.  */
struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
void sctp_endpoint_free(struct sctp_endpoint *);
void sctp_endpoint_put(struct sctp_endpoint *);
void sctp_endpoint_hold(struct sctp_endpoint *);
void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
struct sctp_association *sctp_endpoint_lookup_assoc(
	const struct sctp_endpoint *ep,
	const union sctp_addr *paddr,
	struct sctp_transport **);
int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
				const union sctp_addr *);
struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
					struct net *, const union sctp_addr *);
int sctp_has_association(struct net *net, const union sctp_addr *laddr,
			 const union sctp_addr *paddr);

int sctp_verify_init(struct net *net, const struct sctp_association *asoc,
		     sctp_cid_t, sctp_init_chunk_t *peer_init,
		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
		      const union sctp_addr *peer,
		      sctp_init_chunk_t *init, gfp_t gfp);
__u32 sctp_generate_tag(const struct sctp_endpoint *);
__u32 sctp_generate_tsn(const struct sctp_endpoint *);

struct sctp_inithdr_host {
	__u32 init_tag;
	__u32 a_rwnd;
	__u16 num_outbound_streams;
	__u16 num_inbound_streams;
	__u32 initial_tsn;
};

/* SCTP_GET_ASSOC_STATS counters */
struct sctp_priv_assoc_stats {
	/* Maximum observed rto in the association during subsequent
	 * observations. Value is set to 0 if no RTO measurement took place
	 * The transport where the max_rto was observed is returned in
	 * obs_rto_ipaddr
	 */
	struct sockaddr_storage obs_rto_ipaddr;
	__u64 max_obs_rto;
	/* Total In and Out SACKs received and sent */
	__u64 isacks;
	__u64 osacks;
	/* Total In and Out packets received and sent */
	__u64 opackets;
	__u64 ipackets;
	/* Total retransmitted chunks */
	__u64 rtxchunks;
	/* TSN received > next expected */
	__u64 outofseqtsns;
	/* Duplicate Chunks received */
	__u64 idupchunks;
	/* Gap Ack Blocks received */
	__u64 gapcnt;
	/* Unordered data chunks sent and received */
	__u64 ouodchunks;
	__u64 iuodchunks;
	/* Ordered data chunks sent and received */
	__u64 oodchunks;
	__u64 iodchunks;
	/* Control chunks sent and received */
	__u64 octrlchunks;
	__u64 ictrlchunks;
};

/* RFC2960
 *
 * 12. Recommended Transmission Control Block (TCB) Parameters
 *
 * This section details a recommended set of parameters that should
 * be contained within the TCB for an implementation. This section is
 * for illustrative purposes and should not be deemed as requirements
 * on an implementation or as an exhaustive list of all parameters
 * inside an SCTP TCB. Each implementation may need its own additional
 * parameters for optimization.
 */


/* Here we have information about each individual association. */
struct sctp_association {

	/* A base structure common to endpoint and association.
	 * In this context, it represents the associations's view
	 * of the local endpoint of the association.
	 */
	struct sctp_ep_common base;

	/* Associations on the same socket. */
	struct list_head asocs;

	/* association id. */
	sctp_assoc_t assoc_id;

	/* This is our parent endpoint.	 */
	struct sctp_endpoint *ep;

	/* These are those association elements needed in the cookie.  */
	struct sctp_cookie c;

	/* This is all information about our peer.  */
	struct {
		/* rwnd
		 *
		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
		 */
		__u32 rwnd;

		/* transport_addr_list
		 *
		 * Peer	       : A list of SCTP transport addresses that the
		 * Transport   : peer is bound to. This information is derived
		 * Address     : from the INIT or INIT ACK and is used to
		 * List	       : associate an inbound packet with a given
		 *	       : association. Normally this information is
		 *	       : hashed or keyed for quick lookup and access
		 *	       : of the TCB.
		 *	       : The list is also initialized with the list
		 *	       : of addresses passed with the sctp_connectx()
		 *	       : call.
		 *
		 * It is a list of SCTP_transport's.
		 */
		struct list_head transport_addr_list;

		/* transport_count
		 *
		 * Peer        : A count of the number of peer addresses
		 * Transport   : in the Peer Transport Address List.
		 * Address     :
		 * Count       :
		 */
		__u16 transport_count;

		/* port
		 *   The transport layer port number.
		 */
		__u16 port;

		/* primary_path
		 *
		 * Primary     : This is the current primary destination
		 * Path	       : transport address of the peer endpoint.  It
		 *	       : may also specify a source transport address
		 *	       : on this endpoint.
		 *
		 * All of these paths live on transport_addr_list.
		 *
		 * At the bakeoffs, we discovered that the intent of
		 * primaryPath is that it only changes when the ULP
		 * asks to have it changed.  We add the activePath to
		 * designate the connection we are currently using to
		 * transmit new data and most control chunks.
		 */
		struct sctp_transport *primary_path;

		/* Cache the primary path address here, when we
		 * need a an address for msg_name.
		 */
		union sctp_addr primary_addr;

		/* active_path
		 *   The path that we are currently using to
		 *   transmit new data and most control chunks.
		 */
		struct sctp_transport *active_path;

		/* retran_path
		 *
		 * RFC2960 6.4 Multi-homed SCTP Endpoints
		 * ...
		 * Furthermore, when its peer is multi-homed, an
		 * endpoint SHOULD try to retransmit a chunk to an
		 * active destination transport address that is
		 * different from the last destination address to
		 * which the DATA chunk was sent.
		 */
		struct sctp_transport *retran_path;

		/* Pointer to last transport I have sent on.  */
		struct sctp_transport *last_sent_to;

		/* This is the last transport I have received DATA on.	*/
		struct sctp_transport *last_data_from;

		/*
		 * Mapping  An array of bits or bytes indicating which out of
		 * Array    order TSN's have been received (relative to the
		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
		 *	    order packets have been received, this array
		 *	    will be set to all zero. This structure may be
		 *	    in the form of a circular buffer or bit array.
		 *
		 * Last Rcvd   : This is the last TSN received in
		 * TSN	       : sequence. This value is set initially by
		 *	       : taking the peer's Initial TSN, received in
		 *	       : the INIT or INIT ACK chunk, and subtracting
		 *	       : one from it.
		 *
		 * Throughout most of the specification this is called the
		 * "Cumulative TSN ACK Point".	In this case, we
		 * ignore the advice in 12.2 in favour of the term
		 * used in the bulk of the text.  This value is hidden
		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
		 */
		struct sctp_tsnmap tsn_map;

		/* Ack State   : This flag indicates if the next received
		 *             : packet is to be responded to with a
		 *             : SACK. This is initializedto 0.  When a packet
		 *             : is received it is incremented. If this value
		 *             : reaches 2 or more, a SACK is sent and the
		 *             : value is reset to 0. Note: This is used only
		 *             : when no DATA chunks are received out of
		 *             : order.  When DATA chunks are out of order,
		 *             : SACK's are not delayed (see Section 6).
		 */
		__u8    sack_needed;     /* Do we need to sack the peer? */
		__u32	sack_cnt;
		__u32	sack_generation;

		/* These are capabilities which our peer advertised.  */
		__u8	ecn_capable:1,	    /* Can peer do ECN? */
			ipv4_address:1,	    /* Peer understands IPv4 addresses? */
			ipv6_address:1,	    /* Peer understands IPv6 addresses? */
			hostname_address:1, /* Peer understands DNS addresses? */
			asconf_capable:1,   /* Does peer support ADDIP? */
			prsctp_capable:1,   /* Can peer do PR-SCTP? */
			auth_capable:1;	    /* Is peer doing SCTP-AUTH? */

		__u32   adaptation_ind;	 /* Adaptation Code point. */

		/* This mask is used to disable sending the ASCONF chunk
		 * with specified parameter to peer.
		 */
		__be16 addip_disabled_mask;

		struct sctp_inithdr_host i;
		int cookie_len;
		void *cookie;

		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
		 * Initial TSN Value minus 1
		 */
		__u32 addip_serial;

		/* SCTP-AUTH: We need to know pears random number, hmac list
		 * and authenticated chunk list.  All that is part of the
		 * cookie and these are just pointers to those locations
		 */
		sctp_random_param_t *peer_random;
		sctp_chunks_param_t *peer_chunks;
		sctp_hmac_algo_param_t *peer_hmacs;
	} peer;

	/* State       : A state variable indicating what state the
	 *	       : association is in, i.e. COOKIE-WAIT,
	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
	 *
	 *		Note: No "CLOSED" state is illustrated since if a
	 *		association is "CLOSED" its TCB SHOULD be removed.
	 *
	 *		In this implementation we DO have a CLOSED
	 *		state which is used during initiation and shutdown.
	 *
	 *		State takes values from SCTP_STATE_*.
	 */
	sctp_state_t state;

	/* The cookie life I award for any cookie.  */
	ktime_t cookie_life;

	/* Overall     : The overall association error count.
	 * Error Count : [Clear this any time I get something.]
	 */
	int overall_error_count;

	/* These are the association's initial, max, and min RTO values.
	 * These values will be initialized by system defaults, but can
	 * be modified via the SCTP_RTOINFO socket option.
	 */
	unsigned long rto_initial;
	unsigned long rto_max;
	unsigned long rto_min;

	/* Maximum number of new data packets that can be sent in a burst.  */
	int max_burst;

	/* This is the max_retrans value for the association.  This value will
	 * be initialized initialized from system defaults, but can be
	 * modified by the SCTP_ASSOCINFO socket option.
	 */
	int max_retrans;

	/* This is the partially failed retrans value for the transport
	 * and will be initialized from the assocs value.  This can be
	 * changed using the SCTP_PEER_ADDR_THLDS socket option
	 */
	int pf_retrans;

	/* Maximum number of times the endpoint will retransmit INIT  */
	__u16 max_init_attempts;

	/* How many times have we resent an INIT? */
	__u16 init_retries;

	/* The largest timeout or RTO value to use in attempting an INIT */
	unsigned long max_init_timeo;

	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
	 * the destination address every heartbeat interval. This value
	 * will be inherited by all new transports.
	 */
	unsigned long hbinterval;

	/* This is the max_retrans value for new transports in the
	 * association.
	 */
	__u16 pathmaxrxt;

	/* Flag that path mtu update is pending */
	__u8   pmtu_pending;

	/* Association : The smallest PMTU discovered for all of the
	 * PMTU	       : peer's transport addresses.
	 */
	__u32 pathmtu;

	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
	__u32 param_flags;

	/* SACK delay timeout */
	unsigned long sackdelay;
	__u32 sackfreq;


	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];

	/* Transport to which SHUTDOWN chunk was last sent.  */
	struct sctp_transport *shutdown_last_sent_to;

	/* How many times have we resent a SHUTDOWN */
	int shutdown_retries;

	/* Transport to which INIT chunk was last sent.  */
	struct sctp_transport *init_last_sent_to;

	/* Next TSN    : The next TSN number to be assigned to a new
	 *	       : DATA chunk.  This is sent in the INIT or INIT
	 *	       : ACK chunk to the peer and incremented each
	 *	       : time a DATA chunk is assigned a TSN
	 *	       : (normally just prior to transmit or during
	 *	       : fragmentation).
	 */
	__u32 next_tsn;

	/*
	 * Last Rcvd   : This is the last TSN received in sequence.  This value
	 * TSN	       : is set initially by taking the peer's Initial TSN,
	 *	       : received in the INIT or INIT ACK chunk, and
	 *	       : subtracting one from it.
	 *
	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
	 */

	__u32 ctsn_ack_point;

	/* PR-SCTP Advanced.Peer.Ack.Point */
	__u32 adv_peer_ack_point;

	/* Highest TSN that is acknowledged by incoming SACKs. */
	__u32 highest_sacked;

	/* TSN marking the fast recovery exit point */
	__u32 fast_recovery_exit;

	/* Flag to track the current fast recovery state */
	__u8 fast_recovery;

	/* The number of unacknowledged data chunks.  Reported through
	 * the SCTP_STATUS sockopt.
	 */
	__u16 unack_data;

	/* The total number of data chunks that we've had to retransmit
	 * as the result of a T3 timer expiration
	 */
	__u32 rtx_data_chunks;

	/* This is the association's receive buffer space.  This value is used
	 * to set a_rwnd field in an INIT or a SACK chunk.
	 */
	__u32 rwnd;

	/* This is the last advertised value of rwnd over a SACK chunk. */
	__u32 a_rwnd;

	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
	 * to slop over a maximum of the association's frag_point.
	 */
	__u32 rwnd_over;

	/* Keeps treack of rwnd pressure.  This happens when we have
	 * a window, but not recevie buffer (i.e small packets).  This one
	 * is releases slowly (1 PMTU at a time ).
	 */
	__u32 rwnd_press;

	/* This is the sndbuf size in use for the association.
	 * This corresponds to the sndbuf size for the association,
	 * as specified in the sk->sndbuf.
	 */
	int sndbuf_used;

	/* This is the amount of memory that this association has allocated
	 * in the receive path at any given time.
	 */
	atomic_t rmem_alloc;

	/* This is the wait queue head for send requests waiting on
	 * the association sndbuf space.
	 */
	wait_queue_head_t	wait;

	/* The message size at which SCTP fragmentation will occur. */
	__u32 frag_point;
	__u32 user_frag;

	/* Counter used to count INIT errors. */
	int init_err_counter;

	/* Count the number of INIT cycles (for doubling timeout). */
	int init_cycle;

	/* Default send parameters. */
	__u16 default_stream;
	__u16 default_flags;
	__u32 default_ppid;
	__u32 default_context;
	__u32 default_timetolive;

	/* Default receive parameters */
	__u32 default_rcv_context;

	/* This tracks outbound ssn for a given stream.	 */
	struct sctp_ssnmap *ssnmap;

	/* All outbound chunks go through this structure.  */
	struct sctp_outq outqueue;

	/* A smart pipe that will handle reordering and fragmentation,
	 * as well as handle passing events up to the ULP.
	 */
	struct sctp_ulpq ulpq;

	/* Last TSN that caused an ECNE Chunk to be sent.  */
	__u32 last_ecne_tsn;

	/* Last TSN that caused a CWR Chunk to be sent.	 */
	__u32 last_cwr_tsn;

	/* How many duplicated TSNs have we seen?  */
	int numduptsns;

	/* Number of seconds of idle time before an association is closed.
	 * In the association context, this is really used as a boolean
	 * since the real timeout is stored in the timeouts array
	 */
	__u32 autoclose;

	/* These are to support
	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
	 *  and Enforcement of Flow and Message Limits"
	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
	 * or "ADDIP" for short.
	 */



	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
	 *
	 * R1) One and only one ASCONF Chunk MAY be in transit and
	 * unacknowledged at any one time.  If a sender, after sending
	 * an ASCONF chunk, decides it needs to transfer another
	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
	 * returns from the previous ASCONF Chunk before sending a
	 * subsequent ASCONF. Note this restriction binds each side,
	 * so at any time two ASCONF may be in-transit on any given
	 * association (one sent from each endpoint).
	 *
	 * [This is our one-and-only-one ASCONF in flight.  If we do
	 * not have an ASCONF in flight, this is NULL.]
	 */
	struct sctp_chunk *addip_last_asconf;

	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
	 *
	 * This is needed to implement itmes E1 - E4 of the updated
	 * spec.  Here is the justification:
	 *
	 * Since the peer may bundle multiple ASCONF chunks toward us,
	 * we now need the ability to cache multiple ACKs.  The section
	 * describes in detail how they are cached and cleaned up.
	 */
	struct list_head asconf_ack_list;

	/* These ASCONF chunks are waiting to be sent.
	 *
	 * These chunaks can't be pushed to outqueue until receiving
	 * ASCONF_ACK for the previous ASCONF indicated by
	 * addip_last_asconf, so as to guarantee that only one ASCONF
	 * is in flight at any time.
	 *
	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
	 *
	 * In defining the ASCONF Chunk transfer procedures, it is
	 * essential that these transfers MUST NOT cause congestion
	 * within the network.	To achieve this, we place these
	 * restrictions on the transfer of ASCONF Chunks:
	 *
	 * R1) One and only one ASCONF Chunk MAY be in transit and
	 * unacknowledged at any one time.  If a sender, after sending
	 * an ASCONF chunk, decides it needs to transfer another
	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
	 * returns from the previous ASCONF Chunk before sending a
	 * subsequent ASCONF. Note this restriction binds each side,
	 * so at any time two ASCONF may be in-transit on any given
	 * association (one sent from each endpoint).
	 *
	 *
	 * [I really think this is EXACTLY the sort of intelligence
	 *  which already resides in sctp_outq.	 Please move this
	 *  queue and its supporting logic down there.	--piggy]
	 */
	struct list_head addip_chunk_list;

	/* ADDIP Section 4.1 ASCONF Chunk Procedures
	 *
	 * A2) A serial number should be assigned to the Chunk. The
	 * serial number SHOULD be a monotonically increasing
	 * number. The serial number SHOULD be initialized at
	 * the start of the association to the same value as the
	 * Initial TSN and every time a new ASCONF chunk is created
	 * it is incremented by one after assigning the serial number
	 * to the newly created chunk.
	 *
	 * ADDIP
	 * 3.1.1  Address/Stream 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
	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
	 * after reaching 4294967295.
	 */
	__u32 addip_serial;
	union sctp_addr *asconf_addr_del_pending;
	int src_out_of_asoc_ok;
	struct sctp_transport *new_transport;

	/* SCTP AUTH: list of the endpoint shared keys.  These
	 * keys are provided out of band by the user applicaton
	 * and can't change during the lifetime of the association
	 */
	struct list_head endpoint_shared_keys;

	/* SCTP AUTH:
	 * The current generated assocaition shared key (secret)
	 */
	struct sctp_auth_bytes *asoc_shared_key;

	/* SCTP AUTH: hmac id of the first peer requested algorithm
	 * that we support.
	 */
	__u16 default_hmac_id;

	__u16 active_key_id;

	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
	     temp:1;		/* Is it a temporary association? */

	struct sctp_priv_assoc_stats stats;
};


/* An eyecatcher for determining if we are really looking at an
 * association data structure.
 */
enum {
	SCTP_ASSOC_EYECATCHER = 0xa550c123,
};

/* Recover the outter association structure. */
static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
{
	struct sctp_association *asoc;

	asoc = container_of(base, struct sctp_association, base);
	return asoc;
}

/* These are function signatures for manipulating associations.	 */


struct sctp_association *
sctp_association_new(const struct sctp_endpoint *, const struct sock *,
		     sctp_scope_t scope, gfp_t gfp);
void sctp_association_free(struct sctp_association *);
void sctp_association_put(struct sctp_association *);
void sctp_association_hold(struct sctp_association *);

struct sctp_transport *sctp_assoc_choose_alter_transport(
	struct sctp_association *, struct sctp_transport *);
void sctp_assoc_update_retran_path(struct sctp_association *);
struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
					  const union sctp_addr *);
int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
			    const union sctp_addr *laddr);
struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
				     const union sctp_addr *address,
				     const gfp_t gfp,
				     const int peer_state);
void sctp_assoc_del_peer(struct sctp_association *asoc,
			 const union sctp_addr *addr);
void sctp_assoc_rm_peer(struct sctp_association *asoc,
			 struct sctp_transport *peer);
void sctp_assoc_control_transport(struct sctp_association *,
				  struct sctp_transport *,
				  sctp_transport_cmd_t, sctp_sn_error_t);
struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
					   struct net *,
					   const union sctp_addr *,
					   const union sctp_addr *);
void sctp_assoc_migrate(struct sctp_association *, struct sock *);
void sctp_assoc_update(struct sctp_association *old,
		       struct sctp_association *new);

__u32 sctp_association_get_next_tsn(struct sctp_association *);

void sctp_assoc_sync_pmtu(struct sock *, struct sctp_association *);
void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
void sctp_assoc_set_primary(struct sctp_association *,
			    struct sctp_transport *);
void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
				    struct sctp_transport *);
int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *,
				     sctp_scope_t, gfp_t);
int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
					 struct sctp_cookie*,
					 gfp_t gfp);
int sctp_assoc_set_id(struct sctp_association *, gfp_t);
void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
					const struct sctp_association *asoc,
					__be32 serial);
void sctp_asconf_queue_teardown(struct sctp_association *asoc);

int sctp_cmp_addr_exact(const union sctp_addr *ss1,
			const union sctp_addr *ss2);
struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);

/* A convenience structure to parse out SCTP specific CMSGs. */
typedef struct sctp_cmsgs {
	struct sctp_initmsg *init;
	struct sctp_sndrcvinfo *info;
} sctp_cmsgs_t;

/* Structure for tracking memory objects */
typedef struct {
	char *label;
	atomic_t *counter;
} sctp_dbg_objcnt_entry_t;

#endif /* __sctp_structs_h__ */