structs.h

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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, 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 use_as_src, 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 *);
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(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 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.
	 *   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;
};


/* 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;

 	/* 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 *,
					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, 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;
};

/* 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;
		__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? */
		__u8	auth_capable;	 /* 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;