A cache implementation for nanocoap response messages. More...

Detailed Description

A cache implementation for nanocoap response messages.

Files
file	cache.h
	nanocoap-cache API

Data Structures
struct	nanocoap_cache_entry_t
	Cache container that holds a `coap_pkt_t` struct. More...

Macros
#define	CONFIG_NANOCOAP_CACHE_ENTRIES (8)
	The number of maximum cache entries. More...

#define	CONFIG_NANOCOAP_CACHE_KEY_LENGTH (8)
	The length of the cache key in bytes. More...

#define	CONFIG_NANOCOAP_CACHE_RESPONSE_SIZE (128)
	Size of the buffer to store responses in the cache. More...

Typedefs
typedef int(*	nanocoap_cache_replacement_strategy_t) (void)
	Typedef for the cache replacement strategy on full cache list. More...

typedef int(*	nanocoap_cache_update_strategy_t) (clist_node_t *node)
	Typedef for the cache update strategy on element access. More...

Functions
static void	nanocoap_cache_init (void)
	Initializes the internal state of the nanocoap cache. More...

size_t	nanocoap_cache_used_count (void)
	Returns the number of cached entries. More...

size_t	nanocoap_cache_free_count (void)
	Returns the number of unused cache entries. More...

nanocoap_cache_entry_t *	nanocoap_cache_process (const uint8_t cache_key, unsigned request_method, const coap_pkt_t resp, size_t resp_len)
	Determines if a response is cacheable and modifies the cache as reflected in RFC7252, Section 5.9. More...

nanocoap_cache_entry_t *	nanocoap_cache_add_by_req (const coap_pkt_t req, const coap_pkt_t resp, size_t resp_len)
	Creates a new or gets an existing cache entry using the request packet. More...

nanocoap_cache_entry_t *	nanocoap_cache_add_by_key (const uint8_t cache_key, unsigned request_method, const coap_pkt_t resp, size_t resp_len)
	Creates a new or gets an existing cache entry using the cache key. More...

nanocoap_cache_entry_t *	nanocoap_cache_request_lookup (const coap_pkt_t *req)
	Performs a cache lookup based on the `req`. More...

nanocoap_cache_entry_t *	nanocoap_cache_key_lookup (const uint8_t *cache_key)
	Performs a cache lookup based on the cache key of a request. More...

int	nanocoap_cache_del (const nanocoap_cache_entry_t *ce)
	Deletes the provided cache entry `ce`. More...

void	nanocoap_cache_key_generate (const coap_pkt_t req, uint8_t cache_key)
	Generates a cache key based on the request `req`. More...

ssize_t	nanocoap_cache_key_compare (uint8_t cache_key1, uint8_t cache_key2)
	Compares two cache keys. More...

static bool	nanocoap_cache_entry_is_stale (const nanocoap_cache_entry_t *ce, uint32_t now)
	Check if the Max-Age of a cache entry has passed. More...

Macro Definition Documentation

◆ CONFIG_NANOCOAP_CACHE_ENTRIES

#define CONFIG_NANOCOAP_CACHE_ENTRIES (8)

The number of maximum cache entries.

Definition at line 41 of file cache.h.

◆ CONFIG_NANOCOAP_CACHE_KEY_LENGTH

#define CONFIG_NANOCOAP_CACHE_KEY_LENGTH (8)

The length of the cache key in bytes.

Definition at line 48 of file cache.h.

◆ CONFIG_NANOCOAP_CACHE_RESPONSE_SIZE

#define CONFIG_NANOCOAP_CACHE_RESPONSE_SIZE (128)

Size of the buffer to store responses in the cache.

Definition at line 55 of file cache.h.

Typedef Documentation

◆ nanocoap_cache_replacement_strategy_t

typedef int(* nanocoap_cache_replacement_strategy_t) (void)

Typedef for the cache replacement strategy on full cache list.

Returns: 0 on successfully replacing a cache element; -1 on error

Definition at line 102 of file cache.h.

◆ nanocoap_cache_update_strategy_t

typedef int(* nanocoap_cache_update_strategy_t) (clist_node_t *node)

Typedef for the cache update strategy on element access.

Parameters

[in] node The accessed node.

Returns: 0 on successfully updating the element; -1 on error

Definition at line 112 of file cache.h.

Function Documentation

◆ nanocoap_cache_add_by_key()

nanocoap_cache_entry_t * nanocoap_cache_add_by_key	(	const uint8_t *	cache_key,
		unsigned	request_method,
		const coap_pkt_t *	resp,
		size_t	resp_len
	)

Creates a new or gets an existing cache entry using the cache key.

Parameters

[in]	cache_key	The cache key of the request
[in]	request_method	The method of the initial request
[in]	resp	The response to add to the cache
[in]	resp_len	The actual length of the response in `resp`

Returns: The previously existing or newly added cache entry on success; NULL, if there is no space left

◆ nanocoap_cache_add_by_req()

nanocoap_cache_entry_t * nanocoap_cache_add_by_req	(	const coap_pkt_t *	req,
		const coap_pkt_t *	resp,
		size_t	resp_len
	)

Creates a new or gets an existing cache entry using the request packet.

Parameters

[in]	req	The request to calculate the cache-key
[in]	resp	The response to add to the cache
[in]	resp_len	The actual length of the response message in `resp`

Returns: The previously existing or newly added cache entry on success; NULL, if there is no space left

◆ nanocoap_cache_del()

int nanocoap_cache_del ( const nanocoap_cache_entry_t * ce )

Deletes the provided cache entry ce.

Parameters

[in] ce The cache entry to delete

Returns: 0 on success; -1 if entry is not available in the cache

◆ nanocoap_cache_entry_is_stale()

static bool nanocoap_cache_entry_is_stale	(	const nanocoap_cache_entry_t *	ce,
		uint32_t	now
	)

inlinestatic

Check if the Max-Age of a cache entry has passed.

Parameters

[in]	ce	A cache entry
[in]	now	The current time

Returns: true, if Max-Age of cache entry has passed.; false, if Max-Age of cache entry has not yet passed.

Definition at line 243 of file cache.h.

◆ nanocoap_cache_free_count()

size_t nanocoap_cache_free_count ( void )

Returns the number of unused cache entries.

Returns: Number of unused cache entries

◆ nanocoap_cache_init()

static void nanocoap_cache_init ( void )

inlinestatic

Initializes the internal state of the nanocoap cache.

Definition at line 120 of file cache.h.

◆ nanocoap_cache_key_compare()

ssize_t nanocoap_cache_key_compare	(	uint8_t *	cache_key1,
		uint8_t *	cache_key2
	)

Compares two cache keys.

Parameters

[in]	cache_key1	The first cache key in the comparison
[in]	cache_key2	The second cache key in the comparison

Returns: 0 if cache keys are equal; <0 or 0> (see memcmp()) for unequal cache keys

◆ nanocoap_cache_key_generate()

void nanocoap_cache_key_generate	(	const coap_pkt_t *	req,
		uint8_t *	cache_key
	)

Generates a cache key based on the request req.

Parameters

[in]	req	The request to generate the cache key from
[out]	cache_key	The generated cache key

◆ nanocoap_cache_key_lookup()

nanocoap_cache_entry_t * nanocoap_cache_key_lookup ( const uint8_t * cache_key )

Performs a cache lookup based on the cache key of a request.

Parameters

[in] cache_key The cache key of a request

Returns: An existing cache entry on cache hit; NULL on cache miss

◆ nanocoap_cache_process()

nanocoap_cache_entry_t * nanocoap_cache_process	(	const uint8_t *	cache_key,
		unsigned	request_method,
		const coap_pkt_t *	resp,
		size_t	resp_len
	)

Determines if a response is cacheable and modifies the cache as reflected in RFC7252, Section 5.9.

Parameters

[in]	cache_key	The cache key of the request
[in]	request_method	The method of the initial request
[in]	resp	The response to operate on
[in]	resp_len	The actual length of the response in `resp`

Returns: The cache entry on successfully handling the response; NULL on error

◆ nanocoap_cache_request_lookup()

nanocoap_cache_entry_t * nanocoap_cache_request_lookup ( const coap_pkt_t * req )

Performs a cache lookup based on the req.

Parameters

[in] req The request to calculate the cache-key

Returns: An existing cache entry on cache hit; NULL on cache miss

◆ nanocoap_cache_used_count()

size_t nanocoap_cache_used_count ( void )

Returns the number of cached entries.

Returns: Number of cached entries

Detailed Description

Files

Data Structures

Macros

Typedefs

Functions

Macro Definition Documentation

◆ CONFIG_NANOCOAP_CACHE_ENTRIES

◆ CONFIG_NANOCOAP_CACHE_KEY_LENGTH

◆ CONFIG_NANOCOAP_CACHE_RESPONSE_SIZE

Typedef Documentation

◆ nanocoap_cache_replacement_strategy_t

◆ nanocoap_cache_update_strategy_t

Function Documentation

◆ nanocoap_cache_add_by_key()

◆ nanocoap_cache_add_by_req()

◆ nanocoap_cache_del()

◆ nanocoap_cache_entry_is_stale()

◆ nanocoap_cache_free_count()

◆ nanocoap_cache_init()

◆ nanocoap_cache_key_compare()

◆ nanocoap_cache_key_generate()

◆ nanocoap_cache_key_lookup()

◆ nanocoap_cache_process()

◆ nanocoap_cache_request_lookup()

◆ nanocoap_cache_used_count()