API functions for access option filters. More...

Data Structures
struct	coap_opt_iterator_t
	Iterator to run through PDU options. More...

struct	coap_optlist_t
	Representation of chained list of CoAP options to install. More...

Macros
#define	COAP_OPT_FILTER_SHORT 6
	The number of option types below 256 that can be stored in an option filter. More...

#define	COAP_OPT_FILTER_LONG 2
	The number of option types above 255 that can be stored in an option filter. More...

#define	COAP_OPT_FILTER_SIZE (((COAP_OPT_FILTER_SHORT + 1) >> 1) + COAP_OPT_FILTER_LONG) +1
	The number of elements in coap_opt_filter_t. More...

#define	COAP_OPT_ALL NULL
	Pre-defined filter that includes all options. More...

Typedefs
typedef uint16_t	coap_opt_filter_t[COAP_OPT_FILTER_SIZE]
	Fixed-size vector we use for option filtering. More...

typedef struct coap_optlist_t	coap_optlist_t
	Representation of chained list of CoAP options to install. More...

Functions
COAP_STATIC_INLINE void	coap_option_filter_clear (coap_opt_filter_t f)
	Clears filter `f`. More...

int	coap_option_filter_set (coap_opt_filter_t filter, uint16_t type)
	Sets the corresponding entry for `type` in `filter`. More...

int	coap_option_filter_unset (coap_opt_filter_t filter, uint16_t type)
	Clears the corresponding entry for `type` in `filter`. More...

int	coap_option_filter_get (coap_opt_filter_t filter, uint16_t type)
	Checks if `type` is contained in `filter`. More...

coap_opt_iterator_t *	coap_option_iterator_init (const coap_pdu_t pdu, coap_opt_iterator_t oi, const coap_opt_filter_t filter)
	Initializes the given option iterator `oi` to point to the beginning of the `pdu's` option list. More...

coap_opt_t *	coap_option_next (coap_opt_iterator_t *oi)
	Updates the iterator `oi` to point to the next option. More...

coap_opt_t *	coap_check_option (coap_pdu_t pdu, uint16_t type, coap_opt_iterator_t oi)
	Retrieves the first option of type `type` from `pdu`. More...

size_t	coap_opt_setheader (coap_opt_t *opt, size_t maxlen, uint16_t delta, size_t length)
	Encodes the given delta and length values into `opt`. More...

size_t	coap_opt_encode_size (uint16_t delta, size_t length)
	Compute storage bytes needed for an option with given `delta` and `length`. More...

size_t	coap_opt_encode (coap_opt_t opt, size_t n, uint16_t delta, const uint8_t val, size_t length)
	Encodes option with given `delta` into `opt`. More...

uint32_t	coap_opt_length (const coap_opt_t *opt)
	Returns the length of the given option. More...

const uint8_t *	coap_opt_value (const coap_opt_t *opt)
	Returns a pointer to the value of the given option. More...

coap_optlist_t *	coap_new_optlist (uint16_t number, size_t length, const uint8_t *data)
	Create a new optlist entry. More...

int	coap_add_optlist_pdu (coap_pdu_t pdu, coap_optlist_t *optlist_chain)
	The current optlist of `optlist_chain` is first sorted (as per RFC7272 ordering requirements) and then added to the `pdu`. More...

int	coap_insert_optlist (coap_optlist_t *optlist_chain, coap_optlist_t optlist)
	Adds `optlist` to the given `optlist_chain`. More...

void	coap_delete_optlist (coap_optlist_t *optlist_chain)
	Removes all entries from the `optlist_chain`, freeing off their memory usage. More...

Detailed Description

API functions for access option filters.

Macro Definition Documentation

◆ COAP_OPT_ALL

#define COAP_OPT_ALL NULL

Pre-defined filter that includes all options.

Definition at line 122 of file option.h.

◆ COAP_OPT_FILTER_LONG

#define COAP_OPT_FILTER_LONG 2

The number of option types above 255 that can be stored in an option filter.

COAP_OPT_FILTER_SHORT + COAP_OPT_FILTER_LONG must be at most 16. Each coap_option_filter_t object reserves COAP_OPT_FILTER_LONG * 2 bytes for short options.

Definition at line 84 of file option.h.

◆ COAP_OPT_FILTER_SHORT

#define COAP_OPT_FILTER_SHORT 6

The number of option types below 256 that can be stored in an option filter.

COAP_OPT_FILTER_SHORT + COAP_OPT_FILTER_LONG must be at most 16. Each coap_option_filter_t object reserves ((COAP_OPT_FILTER_SHORT + 1) / 2) * 2 bytes for short options.

Definition at line 76 of file option.h.

◆ COAP_OPT_FILTER_SIZE

#define COAP_OPT_FILTER_SIZE (((COAP_OPT_FILTER_SHORT + 1) >> 1) + COAP_OPT_FILTER_LONG) +1

The number of elements in coap_opt_filter_t.

Definition at line 93 of file option.h.

Typedef Documentation

◆ coap_opt_filter_t

typedef uint16_t coap_opt_filter_t[COAP_OPT_FILTER_SIZE]

Fixed-size vector we use for option filtering.

It is large enough to hold COAP_OPT_FILTER_SHORT entries with an option number between 0 and 255, and COAP_OPT_FILTER_LONG entries with an option number between 256 and 65535. Its internal structure is

struct {
  uint16_t mask;
  uint16_t long_opts[COAP_OPT_FILTER_LONG];
  uint8_t short_opts[COAP_OPT_FILTER_SHORT];
}

The first element contains a bit vector that indicates which fields in the remaining array are used. The first COAP_OPT_FILTER_LONG bits correspond to the long option types that are stored in the elements from index 1 to COAP_OPT_FILTER_LONG. The next COAP_OPT_FILTER_SHORT bits correspond to the short option types that are stored in the elements from index COAP_OPT_FILTER_LONG + 1 to COAP_OPT_FILTER_LONG + COAP_OPT_FILTER_SHORT. The latter elements are treated as bytes.

Definition at line 119 of file option.h.

◆ coap_optlist_t

typedef struct coap_optlist_t coap_optlist_t

Representation of chained list of CoAP options to install.

coap_optlist_t *optlist_chain = NULL;
coap_pdu_t *pdu = coap_new_pdu(session);
 
... other set up code ...
coap_insert_optlist(&optlist_chain, coap_new_optlist(COAP_OPTION_OBSERVE,
                   COAP_OBSERVE_ESTABLISH, NULL));
 
coap_add_optlist_pdu(pdu, &optlist_chain);
... other code ...
coap_delete_optlist(optlist_chain);

Function Documentation

◆ coap_add_optlist_pdu()

int coap_add_optlist_pdu	(	coap_pdu_t *	pdu,
		coap_optlist_t **	optlist_chain
	)

The current optlist of optlist_chain is first sorted (as per RFC7272 ordering requirements) and then added to the pdu.

Parameters

pdu	The pdu to add the options to from the chain list
optlist_chain	The chained list of optlist to add to the pdu

Returns: 1 if succesful or 0 if failure;

Definition at line 550 of file option.c.

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◆ coap_check_option()

coap_opt_t* coap_check_option	(	coap_pdu_t *	pdu,
		uint16_t	type,
		coap_opt_iterator_t *	oi
	)

Retrieves the first option of type type from pdu.

oi must point to a coap_opt_iterator_t object that will be initialized by this function to filter only options with code type. This function returns the first option with this type, or NULL if not found.

Parameters

pdu	The PDU to parse for options.
type	The option type code to search for.
oi	An iterator object to use.

Returns: A pointer to the first option of type type, or NULL if not found.

Definition at line 196 of file option.c.

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◆ coap_delete_optlist()

void coap_delete_optlist ( coap_optlist_t * optlist_chain )

Removes all entries from the optlist_chain, freeing off their memory usage.

Parameters

optlist_chain The optlist chain to remove all the entries from

Definition at line 587 of file option.c.

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◆ coap_insert_optlist()

int coap_insert_optlist	(	coap_optlist_t **	optlist_chain,
		coap_optlist_t *	optlist
	)

Adds optlist to the given optlist_chain.

The optlist_chain variable be set to NULL before the initial call to coap_insert_optlist(). The optlist_chain will need to be deleted using coap_delete_optlist() when no longer required.

Parameters

optlist_chain	The chain to add optlist to
optlist	The optlist to add to the queue

Returns: 1 if successful, 0 otherwise.

Definition at line 566 of file option.c.

◆ coap_new_optlist()

coap_optlist_t* coap_new_optlist	(	uint16_t	number,
		size_t	length,
		const uint8_t *	data
	)

Create a new optlist entry.

Parameters

number	The option number (COAP_OPTION_*)
length	The option length
data	The option value data

Returns: A pointer to the new optlist entry, or NULL if error

Definition at line 509 of file option.c.

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◆ coap_opt_encode()

size_t coap_opt_encode	(	coap_opt_t *	opt,
		size_t	n,
		uint16_t	delta,
		const uint8_t *	val,
		size_t	length
	)

Encodes option with given delta into opt.

This function returns the number of bytes written to opt or 0 on error. This happens especially when opt does not provide sufficient space to store the option value, delta, and option jumps when required.

Parameters

opt	The option buffer space where `val` is written.
n	Maximum length of `opt`.
delta	The option delta.
val	The option value to copy into `opt`.
length	The actual length of `val`.

Returns: The number of bytes that have been written to opt or 0 on error. The return value will always be less than n.

Definition at line 369 of file option.c.

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◆ coap_opt_encode_size()

size_t coap_opt_encode_size	(	uint16_t	delta,
		size_t	length
	)

Compute storage bytes needed for an option with given delta and length.

Parameters

delta	The option delta.
length	The option length.

Returns: The number of bytes required to encode this option.

Definition at line 348 of file option.c.

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◆ coap_opt_length()

uint32_t coap_opt_length ( const coap_opt_t * opt )

Returns the length of the given option.

opt must point to an option jump or the beginning of the option. This function returns 0 when opt is not an option or the actual length of opt (which can be 0 as well).

Note: {The rationale for using 0 in case of an error is that in most contexts, the result of this function is used to skip the next coap_opt_length() bytes.}

Parameters

opt	The option whose length should be returned.

Returns: The option's length or 0 when undefined.

Definition at line 209 of file option.c.

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◆ coap_opt_setheader()

size_t coap_opt_setheader	(	coap_opt_t *	opt,
		size_t	maxlen,
		uint16_t	delta,
		size_t	length
	)

Encodes the given delta and length values into opt.

This function returns the number of bytes that were required to encode delta and length or 0 on error. Note that the result indicates by how many bytes opt must be advanced to encode the option value.

Parameters

opt	The option buffer space where `delta` and `length` are written.
maxlen	The maximum length of `opt`.
delta	The actual delta value to encode.
length	The actual length value to encode.

Returns: The number of bytes used or 0 on error.

Definition at line 289 of file option.c.

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◆ coap_opt_value()

const uint8_t* coap_opt_value ( const coap_opt_t * opt )

Returns a pointer to the value of the given option.

opt must point to an option jump or the beginning of the option. This function returns NULL if opt is not a valid option.

Parameters

opt	The option whose value should be returned.

Returns: A pointer to the option value or NULL on error.

Definition at line 246 of file option.c.

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◆ coap_option_filter_clear()

COAP_STATIC_INLINE void coap_option_filter_clear ( coap_opt_filter_t f )

Clears filter f.

Parameters

f	The filter to clear.

Definition at line 130 of file option.h.

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◆ coap_option_filter_get()

int coap_option_filter_get	(	coap_opt_filter_t	filter,
		uint16_t	type
	)

Checks if type is contained in filter.

This function returns 1 if found, 0 if not, or -1 on error (i.e. when the given type does not fit in the filter).

Parameters

filter	The filter object to search.
type	The type to search for.

Returns: 1 if type was found, 0 otherwise, or -1 on error.

Definition at line 504 of file option.c.

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◆ coap_option_filter_set()

int coap_option_filter_set	(	coap_opt_filter_t	filter,
		uint16_t	type
	)

Sets the corresponding entry for type in filter.

This function returns 1 if bit was set or 0 on error (i.e. when the given type does not fit in the filter).

Parameters

filter	The filter object to change.
type	The type for which the bit should be set.

Returns: 1 if bit was set, 0 otherwise.

Definition at line 494 of file option.c.

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◆ coap_option_filter_unset()

int coap_option_filter_unset	(	coap_opt_filter_t	filter,
		uint16_t	type
	)

Clears the corresponding entry for type in filter.

This function returns 1 if bit was set or 0 on error (i.e. when the given type does not fit in the filter).

Parameters

filter	The filter object to change.
type	The type that should be cleared from the filter.

Returns: 1 if bit was set, 0 otherwise.

Definition at line 499 of file option.c.

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◆ coap_option_iterator_init()

coap_opt_iterator_t* coap_option_iterator_init	(	const coap_pdu_t *	pdu,
		coap_opt_iterator_t *	oi,
		const coap_opt_filter_t	filter
	)

Initializes the given option iterator oi to point to the beginning of the pdu's option list.

This function returns oi on success, NULL otherwise (i.e. when no options exist). Note that a length check on the option list must be performed before coap_option_iterator_init() is called.

Parameters

pdu	The PDU the options of which should be walked through.
oi	An iterator object that will be initilized.
filter	An optional option type filter. With `type` != `COAP_OPT_ALL`, coap_option_next() will return only options matching this bitmask. Fence-post options `14`, `28`, `42`, ... are always skipped.

Returns: The iterator object oi on success, NULL otherwise.

Definition at line 110 of file option.c.

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◆ coap_option_next()

coap_opt_t* coap_option_next ( coap_opt_iterator_t * oi )

Updates the iterator oi to point to the next option.

This function returns a pointer to that option or NULL if no more options exist. The contents of oi will be updated. In particular, oi->n specifies the current option's ordinal number (counted from 1), oi->type is the option's type code, and oi->option points to the beginning of the current option itself. When advanced past the last option, oi->option will be NULL.

Note that options are skipped whose corresponding bits in the filter specified with coap_option_iterator_init() are 0. Options with type codes that do not fit in this filter hence will always be returned.

Parameters

oi	The option iterator to update.

Returns: The next option or NULL if no more options exist.

Definition at line 146 of file option.c.

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Data Structures

Macros

Typedefs

Functions

Detailed Description

Macro Definition Documentation

◆ COAP_OPT_ALL

◆ COAP_OPT_FILTER_LONG

◆ COAP_OPT_FILTER_SHORT

◆ COAP_OPT_FILTER_SIZE

Typedef Documentation

◆ coap_opt_filter_t

◆ coap_optlist_t

Function Documentation

◆ coap_add_optlist_pdu()

◆ coap_check_option()

◆ coap_delete_optlist()

◆ coap_insert_optlist()

◆ coap_new_optlist()

◆ coap_opt_encode()

◆ coap_opt_encode_size()

◆ coap_opt_length()

◆ coap_opt_setheader()

◆ coap_opt_value()

◆ coap_option_filter_clear()

◆ coap_option_filter_get()

◆ coap_option_filter_set()

◆ coap_option_filter_unset()

◆ coap_option_iterator_init()

◆ coap_option_next()