Cache Support

Internal API for Cache-Key and Cache-Entry support. More...

Collaboration diagram for Cache Support:

Data Structures
struct	coap_digest_t
struct	coap_cache_key_t
struct	coap_cache_entry_t

Typedefs
typedef struct coap_digest_t	coap_digest_t
typedef void	coap_digest_ctx_t

Functions
void	coap_expire_cache_entries (coap_context_t *context)
	Expire coap_cache_entry_t entries.
coap_cache_entry_t *	coap_cache_get_by_key_lkd (coap_context_t *context, const coap_cache_key_t *cache_key)
	Searches for a cache-entry identified by cache_key.
coap_cache_entry_t *	coap_cache_get_by_pdu_lkd (coap_session_t *session, const coap_pdu_t *pdu, coap_cache_session_based_t session_based)
	Searches for a cache-entry corresponding to pdu.
int	coap_cache_ignore_options_lkd (coap_context_t *context, const uint16_t *options, size_t count)
	Define the CoAP options that are not to be included when calculating the cache-key.
coap_cache_entry_t *	coap_new_cache_entry_lkd (coap_session_t *session, const coap_pdu_t *pdu, coap_cache_record_pdu_t record_pdu, coap_cache_session_based_t session_based, unsigned int idle_time)
	Create a new cache-entry hash keyed by cache-key derived from the PDU.
void *	coap_cache_set_app_data2_lkd (coap_cache_entry_t *cache_entry, void *data, coap_app_data_free_callback_t callback)
	Stores data with the given cache_entry, returning the previously stored value or NULL.
coap_digest_ctx_t *	coap_digest_setup (void)
	Initialize a coap_digest.
void	coap_digest_free (coap_digest_ctx_t *digest_ctx)
	Free off coap_digest_ctx_t.
int	coap_digest_update (coap_digest_ctx_t *digest_ctx, const uint8_t *data, size_t data_len)
	Update the coap_digest information with the next chunk of data.
int	coap_digest_final (coap_digest_ctx_t *digest_ctx, coap_digest_t *digest_buffer)
	Finalize the coap_digest information into the provided digest_buffer.

Detailed Description

Internal API for Cache-Key and Cache-Entry support.

Typedef Documentation

coap_digest_ctx_t

typedef void coap_digest_ctx_t

Definition at line 168 of file coap_cache_internal.h.

coap_digest_t

typedef struct coap_digest_t coap_digest_t

Function Documentation

coap_cache_get_by_key_lkd()

coap_cache_entry_t * coap_cache_get_by_key_lkd	(	coap_context_t *	context,
		const coap_cache_key_t *	cache_key
	)

Searches for a cache-entry identified by cache_key.

This function returns the corresponding cache-entry or NULL if not found.

Note: This function must be called in the locked state.

Parameters

context	The context to use.
cache_key	The cache-key to get the hashed coap-entry.

Returns

The cache-entry for cache_key or NULL if not found.

coap_cache_get_by_pdu_lkd()

coap_cache_entry_t * coap_cache_get_by_pdu_lkd	(	coap_session_t *	session,
		const coap_pdu_t *	pdu,
		coap_cache_session_based_t	session_based
	)

Searches for a cache-entry corresponding to pdu.

This function returns the corresponding cache-entry or NULL if not found.

Note: This function must be called in the locked state.

Parameters

session	The session to use.
pdu	The CoAP request to search for.
session_based	COAP_CACHE_IS_SESSION_BASED if session based cache-key to be used, else COAP_CACHE_NOT_SESSION_BASED.

Returns

The cache-entry for request or NULL if not found.

coap_cache_ignore_options_lkd()

int coap_cache_ignore_options_lkd	(	coap_context_t *	context,
		const uint16_t *	options,
		size_t	count
	)

Define the CoAP options that are not to be included when calculating the cache-key.

Options that are defined as Non-Cache and the Observe option are always ignored.

Note: This function must be called in the locked state.

Parameters

context	The context to save the ignored options information in.
options	The array of options to ignore.
count	The number of options to ignore. Use 0 to reset the options matching.

Returns

1 if successful, else 0.

coap_cache_set_app_data2_lkd()

void * coap_cache_set_app_data2_lkd	(	coap_cache_entry_t *	cache_entry,
		void *	data,
		coap_app_data_free_callback_t	callback
	)

Stores data with the given cache_entry, returning the previously stored value or NULL.

The data callback can be defined if the data is to be released when the cache_entry is deleted.

Note: This function must be called in the locked state.

Note: It is the responsibility of the caller to free off (if appropriate) any returned data.

Parameters

cache_entry	The CoAP cache entry.
data	The pointer to the data to store or NULL to just clear out the previous data.
callback	The optional release call-back for data on cache_entry removal or NULL.

Returns

The previous data (if any) stored in the cache_entry.

coap_digest_final()

int coap_digest_final	(	coap_digest_ctx_t *	digest_ctx,
		coap_digest_t *	digest_buffer
	)

Finalize the coap_digest information into the provided digest_buffer.

coap_digest_free() is always called, even if error.

Internal function.

Parameters

digest_ctx	The coap_digest context.
digest_buffer	Pointer to digest buffer to update

Returns

1 success, 0 failure.

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coap_digest_free()

void coap_digest_free

(

coap_digest_ctx_t *

digest_ctx

)

Free off coap_digest_ctx_t.

Always done by coap_digest_final()

Internal function.

Parameters

digest_ctx

The coap_digest context.

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coap_digest_setup()

coap_digest_ctx_t * coap_digest_setup

(

void

)

Initialize a coap_digest.

Internal function.

Returns

The digest context or NULL if failure.

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coap_digest_update()

int coap_digest_update	(	coap_digest_ctx_t *	digest_ctx,
		const uint8_t *	data,
		size_t	data_len
	)

Update the coap_digest information with the next chunk of data.

Internal function.

Parameters

digest_ctx	The coap_digest context.
data	Pointer to data.
data_len	Number of bytes.

Returns

1 success, 0 failure.

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coap_expire_cache_entries()

void coap_expire_cache_entries

(

coap_context_t *

context

)

Expire coap_cache_entry_t entries.

Internal function.

Parameters

context

The context holding the coap-entries to exire

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coap_new_cache_entry_lkd()

coap_cache_entry_t * coap_new_cache_entry_lkd	(	coap_session_t *	session,
		const coap_pdu_t *	pdu,
		coap_cache_record_pdu_t	record_pdu,
		coap_cache_session_based_t	session_based,
		unsigned int	idle_time
	)

Create a new cache-entry hash keyed by cache-key derived from the PDU.

If session_based is set, then this cache-entry will get deleted when the session is freed off. If record_pdu is set, then the copied PDU will get freed off when this cache-entry is deleted.

The cache-entry is maintained on a context hash list.

Note: This function must be called in the locked state.

Parameters

session	The session to use to derive the context from.
pdu	The pdu to use to generate the cache-key.
record_pdu	COAP_CACHE_RECORD_PDU if to take a copy of the PDU for later use, else COAP_CACHE_NOT_RECORD_PDU.
session_based	COAP_CACHE_IS_SESSION_BASED if to associate this cache-entry with the the session (which is embedded in the cache-entry), else COAP_CACHE_NOT_SESSION_BASED.
idle_time	Idle time in seconds before cache-entry is expired. If set to 0, it does not expire (but will get deleted if the session is deleted and it is session_based).

Returns

The returned cache-key or NULL if failure.