structs.h

h内核

	 * using SCTP_SET_PEER_ADDR_PARAMS socket option.
	 */
	int max_retrans;

	/* Per	       : A timer used by each destination.
	 * Destination :
	 * Timer       :
	 *
	 * [Everywhere else in the text this is called T3-rtx. -ed]
	 */
	struct timer_list T3_rtx_timer;

	/* Heartbeat timer is per destination. */
	struct timer_list hb_timer;

	/* Since we're using per-destination retransmission timers
	 * (see above), we're also using per-destination "transmitted"
	 * queues.  This probably ought to be a private struct
	 * accessible only within the outqueue, but it's not, yet.
	 */
	struct list_head transmitted;

	/* We build bundle-able packets for this transport here.  */
	struct sctp_packet packet;

	/* This is the list of transports that have chunks to send.  */
	struct list_head send_ready;

	int malloced; /* Is this structure kfree()able? */

	/* State information saved for SFR_CACC algorithm. The key
	 * idea in SFR_CACC is to maintain state at the sender on a
	 * per-destination basis when a changeover happens.
	 *	char changeover_active;
	 *	char cycling_changeover;
	 *	__u32 next_tsn_at_change;
	 *	char cacc_saw_newack;
	 */
	struct {
		/* An unsigned integer, which stores the next TSN to be
		 * used by the sender, at the moment of changeover.
		 */
		__u32 next_tsn_at_change;

		/* A flag which indicates the occurrence of a changeover */
		char changeover_active;

		/* A flag which indicates whether the change of primary is
		 * the first switch to this destination address during an
		 * active switch.
		 */
		char cycling_changeover;

		/* A temporary flag, which is used during the processing of
		 * a SACK to estimate the causative TSN(s)'s group.
		 */
		char cacc_saw_newack;
	} cacc;
};

struct sctp_transport *sctp_transport_new(const union sctp_addr *, int);
void sctp_transport_set_owner(struct sctp_transport *,
			      struct sctp_association *);
void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
			  struct sctp_sock *);
void sctp_transport_pmtu(struct sctp_transport *);
void sctp_transport_free(struct sctp_transport *);
void sctp_transport_reset_timers(struct sctp_transport *);
void sctp_transport_hold(struct sctp_transport *);
void sctp_transport_put(struct sctp_transport *);
void sctp_transport_update_rto(struct sctp_transport *, __u32);
void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
void sctp_transport_lower_cwnd(struct sctp_transport *, sctp_lower_cwnd_t);
unsigned long sctp_transport_timeout(struct sctp_transport *);


/* This is the structure we use to queue packets as they come into
 * SCTP.  We write packets to it and read chunks from it.
 */
struct sctp_inq {
	/* This is actually a queue of sctp_chunk each
	 * containing a partially decoded packet.
	 */
	struct sk_buff_head in;
	/* This is the packet which is currently off the in queue and is
	 * being worked on through the inbound chunk processing.
	 */
	struct sctp_chunk *in_progress;

	/* This is the delayed task to finish delivering inbound
	 * messages.
	 */
	struct work_struct immediate;

	int malloced;	     /* Is this structure kfree()able?	*/
};

void sctp_inq_init(struct sctp_inq *);
void sctp_inq_free(struct sctp_inq *);
void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
void sctp_inq_set_th_handler(struct sctp_inq *, void (*)(void *), void *);

/* This is the structure we use to hold outbound chunks.  You push
 * chunks in and they automatically pop out the other end as bundled
 * 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 sk_buff_head out;

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

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

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

	/* 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;

	/* Corked? */
	char cork;

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

	/* Are we kfree()able? */
	char malloced;
};

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_flush(struct sctp_outq *, int);
int sctp_outq_sack(struct sctp_outq *, struct sctp_sackhdr *);
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;

	int malloced;	     /* Are we kfree()able?  */
};

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 sctp_bind_addr *dest,
			const struct sctp_bind_addr *src,
			sctp_scope_t scope, int gfp,int flags);
int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
		       int 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 *);
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, int gfp);
int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
			   __u16 port, int gfp);

sctp_scope_t sctp_scope(const union sctp_addr *);
int sctp_in_scope(const union sctp_addr *addr, const sctp_scope_t scope);
int sctp_is_any(const union sctp_addr *addr);
int sctp_addr_is_valid(const union sctp_addr *addr);


/* 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 sctp_ep_common *next;
	struct sctp_ep_common **pprev;
	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.
	 *   malloced - Do we need to kfree this object?
	 */
	atomic_t    refcnt;
	char	    dead;
	char	    malloced;

	/* 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;

	/* Protection during address list comparisons. */
	rwlock_t   addr_lock;
};


/* 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_HOW_MANY_SECRETS][SCTP_SECRET_SIZE];
	int current_key;
	int last_key;
	int key_changed_at;

	/* Default timeouts.  */
	int timeouts[SCTP_NUM_TIMEOUT_TYPES];

	/* Various thresholds.	*/

	/* Name for debugging output... */
	char *debug_name;
};

/* 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 *, int);
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 *,
					const union sctp_addr *);
int sctp_has_association(const union sctp_addr *laddr,
			 const union sctp_addr *paddr);

int sctp_verify_init(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 *, sctp_cid_t cid,
		      const union sctp_addr *peer,
		      sctp_init_chunk_t *init, int gfp);
__u32 sctp_generate_tag(const struct sctp_endpoint *);
__u32 sctp_generate_tsn(const struct sctp_endpoint *);


/* 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.
		 *
		 * It is a list of SCTP_transport's.
		 */
		struct list_head transport_addr_list;

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