structs.h

h内核

		/* 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;
		__u8 _map[sctp_tsnmap_storage_size(SCTP_TSN_MAP_SIZE)];

		/* 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? */

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

		__u32   adaption_ind;	 /* Adaption Code point. */

		/* This mask is used to disable sending the ASCONF chunk
		 * with specified parameter to peer.
		 */
		__u16 addip_disabled_mask;

		struct sctp_inithdr 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;
	} 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.  */
	struct timeval 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.
	 */
	__u32 rto_initial;
	__u32 rto_max;
	__u32 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;

	/* 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 */
	__u16 max_init_timeo;

	int 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;

	/* 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;

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

	/* 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;

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

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

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

	/* Currently only one counter is used to count INIT errors. */
	int counters[SCTP_NUMBER_COUNTERS];

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

	/* 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.  */
	__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 4.2 Upon reception of an ASCONF Chunk.
	 *
	 * IMPLEMENTATION NOTE: As an optimization a receiver may wish
	 * to save the last ASCONF-ACK for some predetermined period
	 * of time and instead of re-processing the ASCONF (with the
	 * same serial number) it may just re-transmit the
	 * ASCONF-ACK. It may wish to use the arrival of a new serial
	 * number to discard the previously saved ASCONF-ACK or any
	 * other means it may choose to expire the saved ASCONF-ACK.
	 *
	 * [This is our saved ASCONF-ACK.  We invalidate it when a new
	 * ASCONF serial number arrives.]
	 */
	struct sctp_chunk *addip_last_asconf_ack;

	/* 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 sk_buff_head addip_chunks;

	/* 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;

	/* Need to send an ECNE Chunk? */
	char need_ecne;

	/* Is it a temporary association? */
	char temp;
};


/* 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, int 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_shutdown_transport(
	struct sctp_association *);
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 int gfp);
void sctp_assoc_del_peer(struct sctp_association *asoc,
			 const union sctp_addr *addr);
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 *,
					   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 sctp_association *);
void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned);
void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned);
void sctp_assoc_set_primary(struct sctp_association *,
			    struct sctp_transport *);
int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *, int);
int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
					 struct sctp_cookie*, int gfp);

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__ */