Provides CoAP functionality optimized for minimal resource usage. More...

Detailed Description

Provides CoAP functionality optimized for minimal resource usage.

nanocoap provides a low-level interface to CoAP messaging to reduce and minimize resource usage. It also provides foundational structures and functions used by gcoap, RIOT's higher level interface.

nanocoap includes both server-side request handling and response generation, and client-side request generation.

Read Request

For a server, nanocoap provides coap_parse() to read a message and generate structures that organize the message content. The primary structure is a coap_pkt_t, with elements for header, option, and payload information.

The table below shows function name templates and attributes for access to the sections of the parsed message.

Section	Description
Header	`coap_get_xxx()`, like `coap_get_type()` and `coap_get_token_len()`
Options	`coap_opt_get_xxx()`, for common options by name, like `coap_opt_get_uri_path()`
Options	`coap_opt_get_xxx()`, for any option by value type, like `coap_opt_get_string()`
Payload	coap_pkt_t `payload` and `payload_len`

Write Response

The simplest responses may be generated with a single call to coap_reply_simple(). This function copies the provided payload into the buffer.

Beyond simple responses, coap_build_reply() begins a response by writing the header. The user then may write options and the payload as described below.

Write Request

As a client, first write the request header with coap_build_hdr(). Then choose a mechanism below for writing options and the payload, if any.

Write Options and Payload

For both server responses and client requests, CoAP uses an Option mechanism to encode message metadata that is not required for each message. For example, the resource URI path is required only for a request, and is encoded as the Uri-Path option.

nanocoap provides two APIs for writing CoAP options:

a convenient API that uses a coap_pkt_t struct to track each option as it is written, and can anticipate a buffer overrun
a minimal API that requires only a reference to the buffer; however, the caller must remember and provide the last option number written, as well as the buffer position

In either case, the caller must write options in order by option number (see "CoAP option numbers"). To manage resource use, nanocoap provides macros to enable each API.

Higher-level, struct-based API

First, use coap_pkt_init() to initialize the coap_pkt_t struct, including the array of options.

Next, use the coap_opt_add_xxx() functions to write each option. These functions are provided in two flavors:

by name, for commonly used options, like coap_opt_add_ct()
by value type, for any option, like coap_opt_add_uint()

Finally, write any message payload at the coap_pkt_t payload pointer attribute. The payload_len attribute provides the available length in the buffer.

This API is enabled by the COAP_WRITE_OPTIONS_STRUCT macro.

Minimal, buffer-based API

Use the coap_opt_put_xxx() functions, which are provided by value type. While writing options, use the return value to track the space remaining in the buffer. Finally, write the payload, if any.

This API is enabled by the COAP_WRITE_OPTIONS_BUFFER macro.

Files
file	nanocoap.h
	nanocoap API

Data Structures
struct	coap_hdr_t
	Raw CoAP PDU header structure. More...

struct	coap_optpos_t
	CoAP option array entry. More...

struct	coap_pkt_t
	CoAP PDU parsing context structure. More...

struct	coap_resource_t
	Type for CoAP resource entry. More...

struct	coap_block1_t
	Block1 helper struct. More...

Macros
#define	COAP_PORT (5683)
	CoAP port to use.

#define	COAP_WELL_KNOWN_CORE_DEFAULT_HANDLER
	Resource definition for the default .well-known/core handler. More...

Typedefs
typedef ssize_t(*	coap_handler_t) (coap_pkt_t pkt, uint8_t buf, size_t len, void *context)
	Resource handler type.

Functions
int	coap_parse (coap_pkt_t pkt, uint8_t buf, size_t len)
	Parse a CoAP PDU. More...

ssize_t	coap_build_reply (coap_pkt_t pkt, unsigned code, uint8_t rbuf, unsigned rlen, unsigned payload_len)
	Build reply to CoAP request. More...

ssize_t	coap_reply_simple (coap_pkt_t pkt, unsigned code, uint8_t buf, size_t len, unsigned ct, const uint8_t *payload, uint8_t payload_len)
	Create CoAP reply (convenience function) More...

ssize_t	coap_handle_req (coap_pkt_t pkt, uint8_t resp_buf, unsigned resp_buf_len)
	Handle incoming CoAP request. More...

ssize_t	coap_build_hdr (coap_hdr_t hdr, unsigned type, uint8_t token, size_t token_len, unsigned code, uint16_t id)
	Builds a CoAP header. More...

size_t	coap_put_option (uint8_t buf, uint16_t lastonum, uint16_t onum, uint8_t odata, size_t olen)
	Insert a CoAP option into buffer. More...

size_t	coap_put_option_ct (uint8_t *buf, uint16_t lastonum, uint16_t content_type)
	Insert content type option into buffer. More...

size_t	coap_put_option_uri (uint8_t buf, uint16_t lastonum, const char uri, uint16_t optnum)
	Insert URI encoded option into buffer. More...

int	coap_get_blockopt (coap_pkt_t pkt, uint16_t option, uint32_t blknum, unsigned *szx)
	Generic block option getter. More...

int	coap_get_block1 (coap_pkt_t pkt, coap_block1_t block1)
	Block1 option getter. More...

size_t	coap_put_option_block1 (uint8_t *buf, uint16_t lastonum, unsigned blknum, unsigned szx, int more)
	Insert block1 option into buffer. More...

size_t	coap_put_block1_ok (uint8_t pkt_pos, coap_block1_t block1, uint16_t lastonum)
	Insert block1 option into buffer (from coap_block1_t) More...

unsigned	coap_get_content_type (coap_pkt_t *pkt)
	Get content type from packet. More...

int	coap_get_uri (coap_pkt_t pkt, uint8_t target)
	Get the packet's request URI. More...

static unsigned	coap_szx2size (unsigned szx)
	Helper to decode SZX value to size in bytes. More...

static unsigned	coap_get_ver (coap_pkt_t *pkt)
	Get the CoAP version number. More...

static unsigned	coap_get_type (coap_pkt_t *pkt)
	Get the message type. More...

static unsigned	coap_get_token_len (coap_pkt_t *pkt)
	Get a message's token length [in byte]. More...

static unsigned	coap_get_code_class (coap_pkt_t *pkt)
	Get a message's code class (3 most significant bits of code) More...

static unsigned	coap_get_code_detail (coap_pkt_t *pkt)
	Get a message's code detail (5 least significant bits of code) More...

static unsigned	coap_get_code_raw (coap_pkt_t *pkt)
	Get a message's raw code (class + detail) More...

static unsigned	coap_get_code (coap_pkt_t *pkt)
	Get a message's code in decimal format ((class * 100) + detail) More...

static unsigned	coap_get_id (coap_pkt_t *pkt)
	Get the message ID of the given CoAP packet. More...

static unsigned	coap_get_total_hdr_len (coap_pkt_t *pkt)
	Get the total header length (4-byte header + token length) More...

static uint8_t	coap_code (unsigned class, unsigned detail)
	Encode given code class and code detail to raw code. More...

static void	coap_hdr_set_code (coap_hdr_t *hdr, uint8_t code)
	Write the given raw message code to given CoAP header. More...

static void	coap_hdr_set_type (coap_hdr_t *hdr, unsigned type)
	Set the message type for the given CoAP header. More...

static unsigned	coap_method2flag (unsigned code)
	Convert message code (request method) into a corresponding bit field. More...

static bool	coap_has_observe (coap_pkt_t *pkt)
	Identifies a packet containing an observe option. More...

static void	coap_clear_observe (coap_pkt_t *pkt)
	Clears the observe option value from a packet. More...

static uint32_t	coap_get_observe (coap_pkt_t *pkt)
	Get the value of the observe option from the given packet. More...

ssize_t	coap_well_known_core_default_handler (coap_pkt_t pkt, uint8_t buf, size_t len, void *context)
	Reference to the default .well-known/core handler defined by the application.

Variables
const coap_resource_t	coap_resources []
	Global CoAP resource list.

const unsigned	coap_resources_numof
	Number of entries in global CoAP resource list.

Nanocoap specific maximum values
#define	NANOCOAP_NOPTS_MAX (16)

#define	NANOCOAP_URI_MAX (64)

CoAP option numbers
#define	COAP_OPT_URI_HOST (3)

#define	COAP_OPT_OBSERVE (6)

#define	COAP_OPT_URI_PATH (11)

#define	COAP_OPT_CONTENT_FORMAT (12)

#define	COAP_OPT_URI_QUERY (15)

#define	COAP_OPT_BLOCK2 (23)

#define	COAP_OPT_BLOCK1 (27)

CoAP packet types
#define	COAP_REQ (0)

#define	COAP_RESP (2)

#define	COAP_RST (3)

Message types -- confirmable, non-confirmable, etc.
#define	COAP_TYPE_CON (0)

#define	COAP_TYPE_NON (1)

#define	COAP_TYPE_ACK (2)

#define	COAP_TYPE_RST (3)

CoAP method codes used in header
#define	COAP_CLASS_REQ (0)

#define	COAP_METHOD_GET (1)

#define	COAP_METHOD_POST (2)

#define	COAP_METHOD_PUT (3)

#define	COAP_METHOD_DELETE (4)

CoAP method flags used in coap_handlers array
#define	COAP_GET (0x1)

#define	COAP_POST (0x2)

#define	COAP_PUT (0x4)

#define	COAP_DELETE (0x8)

Empty CoAP message code
#define	COAP_CODE_EMPTY (0)

Response message codes: success
#define	COAP_CLASS_SUCCESS (2)

#define	COAP_CODE_CREATED ((2 << 5) \| 1)

#define	COAP_CODE_DELETED ((2 << 5) \| 2)

#define	COAP_CODE_VALID ((2 << 5) \| 3)

#define	COAP_CODE_CHANGED ((2 << 5) \| 4)

#define	COAP_CODE_204 ((2 << 5) \| 4)

#define	COAP_CODE_CONTENT ((2 << 5) \| 5)

#define	COAP_CODE_205 ((2 << 5) \| 5)

#define	COAP_CODE_231 ((2 << 5) \| 31)

Response message codes: client error
#define	COAP_CLASS_CLIENT_FAILURE (4)

#define	COAP_CODE_BAD_REQUEST ((4 << 5) \| 0)

#define	COAP_CODE_UNAUTHORIZED ((4 << 5) \| 1)

#define	COAP_CODE_BAD_OPTION ((4 << 5) \| 2)

#define	COAP_CODE_FORBIDDEN ((4 << 5) \| 3)

#define	COAP_CODE_PATH_NOT_FOUND ((4 << 5) \| 4)

#define	COAP_CODE_404 ((4 << 5) \| 4)

#define	COAP_CODE_METHOD_NOT_ALLOWED ((4 << 5) \| 5)

#define	COAP_CODE_NOT_ACCEPTABLE ((4 << 5) \| 6)

#define	COAP_CODE_REQUEST_ENTITY_INCOMPLETE ((4 << 5) \| 8)

#define	COAP_CODE_PRECONDITION_FAILED ((4 << 5) \| 0xC)

#define	COAP_CODE_REQUEST_ENTITY_TOO_LARGE ((4 << 5) \| 0xD)

#define	COAP_CODE_UNSUPPORTED_CONTENT_FORMAT ((4 << 5) \| 0xF)

Response message codes: server error
#define	COAP_CLASS_SERVER_FAILURE (5)

#define	COAP_CODE_INTERNAL_SERVER_ERROR ((5 << 5) \| 0)

#define	COAP_CODE_NOT_IMPLEMENTED ((5 << 5) \| 1)

#define	COAP_CODE_BAD_GATEWAY ((5 << 5) \| 2)

#define	COAP_CODE_SERVICE_UNAVAILABLE ((5 << 5) \| 3)

#define	COAP_CODE_GATEWAY_TIMEOUT ((5 << 5) \| 4)

#define	COAP_CODE_PROXYING_NOT_SUPPORTED ((5 << 5) \| 5)

Content types
#define	COAP_CT_LINK_FORMAT (40)

#define	COAP_CT_XML (41)

#define	COAP_CT_OCTET_STREAM (42)

#define	COAP_CT_EXI (47)

#define	COAP_CT_JSON (50)

Content-Format option codes
#define	COAP_FORMAT_TEXT (0)

#define	COAP_FORMAT_LINK (40)

#define	COAP_FORMAT_OCTET (42)

#define	COAP_FORMAT_JSON (50)

#define	COAP_FORMAT_CBOR (60)

#define	COAP_FORMAT_NONE (65535)
	nanocoap-specific value to indicate no format specified. More...

Observe (RFC 7641) constants
#define	COAP_OBS_REGISTER (0)

#define	COAP_OBS_DEREGISTER (1)

Timing parameters
#define	COAP_ACK_TIMEOUT (2U)

#define	COAP_RANDOM_FACTOR (1.5)

#define	COAP_ACK_VARIANCE (1U)
	Maximum variation for confirmable timeout. More...

#define	COAP_MAX_RETRANSMIT (4)

#define	COAP_NSTART (1)

#define	COAP_DEFAULT_LEISURE (5)

Blockwise transfer (RFC7959)
#define	COAP_BLOCKWISE_NUM_OFF (4)

#define	COAP_BLOCKWISE_MORE_OFF (3)

#define	COAP_BLOCKWISE_SZX_MASK (0x07)

#define	COAP_BLOCKWISE_SZX_MAX (7)

Macro Definition Documentation

#define COAP_ACK_VARIANCE (1U)

Maximum variation for confirmable timeout.

Must be an integer, defined as:

(COAP_ACK_TIMEOUT * COAP_RANDOM_FACTOR) - COAP_ACK_TIMEOUT

Definition at line 294 of file nanocoap.h.

#define COAP_FORMAT_NONE (65535)

nanocoap-specific value to indicate no format specified.

Definition at line 269 of file nanocoap.h.

#define COAP_WELL_KNOWN_CORE_DEFAULT_HANDLER

Value:

{ \
        .path = "/.well-known/core", \
        .methods = COAP_GET, \
        .handler = coap_well_known_core_default_handler \
    }

Resource definition for the default .well-known/core handler.

Definition at line 835 of file nanocoap.h.

Function Documentation

ssize_t coap_build_hdr	(	coap_hdr_t *	hdr,
		unsigned	type,
		uint8_t *	token,
		size_t	token_len,
		unsigned	code,
		uint16_t	id
	)

Builds a CoAP header.

Caller must ensure hdr can hold the header and the full token!

Parameters

[out]	hdr	hdr to fill
[in]	type	CoAP packet type (e.g., COAP_TYPE_CON, ...)
[in]	token	token
[in]	token_len	length of `token`
[in]	code	CoAP code (e.g., COAP_CODE_204, ...)
[in]	id	CoAP request id

Returns: length of resulting header

ssize_t coap_build_reply	(	coap_pkt_t *	pkt,
		unsigned	code,
		uint8_t *	rbuf,
		unsigned	rlen,
		unsigned	payload_len
	)

Build reply to CoAP request.

This function can be used to create a reply to any CoAP request packet. It will create the reply packet header based on parameters from the request (e.g., id, token). Passing a non-zero payload_len will ensure the payload fits into the buffer along with the header.

Parameters

[in]	pkt	packet to reply to
[in]	code	reply code (e.g., COAP_CODE_204)
[out]	rbuf	buffer to write reply to
[in]	rlen	size of `rbuf`
[in]	payload_len	length of payload

Returns: size of reply packet on success; <0 on error

static void coap_clear_observe ( coap_pkt_t * pkt )

inlinestatic

Clears the observe option value from a packet.

Parameters

[in] pkt CoAP packet

Definition at line 806 of file nanocoap.h.

static uint8_t coap_code	(	unsigned	class,
		unsigned	detail
	)

inlinestatic

Encode given code class and code detail to raw code.

Parameters

[in]	class	message code class
[in]	detail	message code detail

Returns: raw message code

Definition at line 742 of file nanocoap.h.

int coap_get_block1	(	coap_pkt_t *	pkt,
		coap_block1_t *	block1
	)

Block1 option getter.

This function gets a CoAP packet's block1 option and parses it into a helper structure.

If no block1 option is present in pkt, the values in block1 will be initialized with zero. That implies both block1->offset and block1->more are also valid in that case, as packet with offset==0 and more==0 means it contains all the payload for the corresponding request.

Parameters

[in]	pkt	pkt to work on
[out]	block1	ptr to preallocated coap_block1_t structure

Returns: 0 if block1 option not present; 1 if structure has been filled

int coap_get_blockopt	(	coap_pkt_t *	pkt,
		uint16_t	option,
		uint32_t *	blknum,
		unsigned *	szx
	)

Generic block option getter.

Parameters

[in]	pkt	pkt to work on
[in]	option	actual block option number to get
[out]	blknum	block number
[out]	szx	SZX value

Returns: -1 if option not found; 0 if more flag is not set; 1 if more flag is set

static unsigned coap_get_code ( coap_pkt_t * pkt )

inlinestatic

Get a message's code in decimal format ((class * 100) + detail)

Parameters

[in] pkt CoAP packet

Returns: message code in decimal format

Definition at line 705 of file nanocoap.h.

static unsigned coap_get_code_class ( coap_pkt_t * pkt )

inlinestatic

Get a message's code class (3 most significant bits of code)

Parameters

[in] pkt CoAP packet

Returns: message code class

Definition at line 669 of file nanocoap.h.

static unsigned coap_get_code_detail ( coap_pkt_t * pkt )

inlinestatic

Get a message's code detail (5 least significant bits of code)

Parameters

[in] pkt CoAP packet

Returns: message code detail

Definition at line 681 of file nanocoap.h.

static unsigned coap_get_code_raw ( coap_pkt_t * pkt )

inlinestatic

Get a message's raw code (class + detail)

Parameters

[in] pkt CoAP packet

Returns: raw message code

Definition at line 693 of file nanocoap.h.

unsigned coap_get_content_type ( coap_pkt_t * pkt )

Get content type from packet.

Parameters

[in] pkt packet to work on

Returns: the packet's content type value if included, COAP_FORMAT_NONE otherwise

static unsigned coap_get_id ( coap_pkt_t * pkt )

inlinestatic

Get the message ID of the given CoAP packet.

Parameters

[in] pkt CoAP packet

Returns: message ID

Definition at line 717 of file nanocoap.h.

static uint32_t coap_get_observe ( coap_pkt_t * pkt )

inlinestatic

Get the value of the observe option from the given packet.

Parameters

[in] pkt CoAP packet

Returns: value of the observe option

Definition at line 818 of file nanocoap.h.

static unsigned coap_get_token_len ( coap_pkt_t * pkt )

inlinestatic

Get a message's token length [in byte].

Parameters

[in] pkt CoAP packet

Returns: length of token in the given message (0-8 byte)

Definition at line 657 of file nanocoap.h.

static unsigned coap_get_total_hdr_len ( coap_pkt_t * pkt )

inlinestatic

Get the total header length (4-byte header + token length)

Parameters

[in] pkt CoAP packet

Returns: total header length

Definition at line 729 of file nanocoap.h.

static unsigned coap_get_type ( coap_pkt_t * pkt )

inlinestatic

Get the message type.

Parameters

[in] pkt CoAP packet

Returns: COAP_TYPE_CON; COAP_TYPE_NON; COAP_TYPE_ACK; COAP_TYPE_RST

Definition at line 645 of file nanocoap.h.

int coap_get_uri	(	coap_pkt_t *	pkt,
		uint8_t *	target
	)

Get the packet's request URI.

This function decodes the pkt's URI option into a "/"-seperated and NULL-terminated string.

Caller must ensure target can hold at least NANOCOAP_URI_MAX bytes!

Parameters

[in]	pkt	pkt to work on
[out]	target	buffer for target URI

Returns: -ENOSPC if URI option is larger than NANOCOAP_URI_MAX; nr of bytes written to target (including '\0')

static unsigned coap_get_ver ( coap_pkt_t * pkt )

inlinestatic

Get the CoAP version number.

Parameters

[in] pkt CoAP packet

Returns: CoAP version number

Definition at line 630 of file nanocoap.h.

ssize_t coap_handle_req	(	coap_pkt_t *	pkt,
		uint8_t *	resp_buf,
		unsigned	resp_buf_len
	)

Handle incoming CoAP request.

This function will find the correct handler, call it and write the reply into resp_buf.

Parameters

[in]	pkt	pointer to (parsed) CoAP packet
[out]	resp_buf	buffer for response
[in]	resp_buf_len	size of response buffer

Returns: size of reply packet on success; <0 on error

static bool coap_has_observe ( coap_pkt_t * pkt )

inlinestatic

Identifies a packet containing an observe option.

Parameters

[in] pkt CoAP packet

Returns: true if observe value is set; false if not

Definition at line 796 of file nanocoap.h.

static void coap_hdr_set_code	(	coap_hdr_t *	hdr,
		uint8_t	code
	)

inlinestatic

Write the given raw message code to given CoAP header.

Parameters

[out]	hdr	CoAP header to write to
[in]	code	raw message code

Definition at line 753 of file nanocoap.h.

static void coap_hdr_set_type	(	coap_hdr_t *	hdr,
		unsigned	type
	)

inlinestatic

Set the message type for the given CoAP header.

Precondition: (type := [0-3])

Parameters

[out]	hdr	CoAP header to write
[in]	type	message type as integer value [0-3]

Definition at line 766 of file nanocoap.h.

static unsigned coap_method2flag ( unsigned code )

inlinestatic

Convert message code (request method) into a corresponding bit field.

Parameters

[in] code request code denoting the request method

Returns: bit field corresponding to the given request method

Definition at line 782 of file nanocoap.h.

int coap_parse	(	coap_pkt_t *	pkt,
		uint8_t *	buf,
		size_t	len
	)

Parse a CoAP PDU.

This function parses a raw CoAP PDU from buf with size len and fills the structure pointed to by pkt. pkt must point to a preallocated coap_pkt_t structure.

Parameters

[out]	pkt	structure to parse into
[in]	buf	pointer to raw packet data
[in]	len	length of packet at `buf`

Returns: 0 on success; <0 on error

size_t coap_put_block1_ok	(	uint8_t *	pkt_pos,
		coap_block1_t *	block1,
		uint16_t	lastonum
	)

Insert block1 option into buffer (from coap_block1_t)

This function is wrapper around coap_put_option_block1(), taking its arguments from a coap_block1_t struct.

It will write option Nr. 27 (COAP_OPT_BLOCK1).

It is safe to be called when block1 was generated for a non-blockwise request.

Parameters

[in]	pkt_pos	buffer to write to
[in]	block1	ptr to block1 struct (created by coap_get_block1())
[in]	lastonum	last option number (must be < 27)

Returns: amount of bytes written to pkt_pos

size_t coap_put_option	(	uint8_t *	buf,
		uint16_t	lastonum,
		uint16_t	onum,
		uint8_t *	odata,
		size_t	olen
	)

Insert a CoAP option into buffer.

This function writes a CoAP option with nr. onum to buf. It handles calculating the option delta (from lastonum), encoding the length from olen and copying the option data from odata.

Parameters

[out]	buf	buffer to write to
[in]	lastonum	number of previous option (for delta calculation), or 0 for first option
[in]	onum	number of option
[in]	odata	ptr to raw option data (or NULL)
[in]	olen	length of `odata` (if any)

Returns: amount of bytes written to buf

size_t coap_put_option_block1	(	uint8_t *	buf,
		uint16_t	lastonum,
		unsigned	blknum,
		unsigned	szx,
		int	more
	)

Insert block1 option into buffer.

Parameters

[out]	buf	buffer to write to
[in]	lastonum	number of previous option (for delta calculation), must be < 27
[in]	blknum	block number
[in]	szx	SXZ value
[in]	more	more flag (1 or 0)

Returns: amount of bytes written to buf

size_t coap_put_option_ct	(	uint8_t *	buf,
		uint16_t	lastonum,
		uint16_t	content_type
	)

Insert content type option into buffer.

Parameters

[out]	buf	buffer to write to
[in]	lastonum	number of previous option (for delta calculation), or 0 if first option
[in]	content_type	content type to set

Returns: amount of bytes written to buf

size_t coap_put_option_uri	(	uint8_t *	buf,
		uint16_t	lastonum,
		const char *	uri,
		uint16_t	optnum
	)

Insert URI encoded option into buffer.

Parameters

[out]	buf	buffer to write to
[in]	lastonum	number of previous option (for delta calculation), or 0 if first option
[in]	uri	ptr to source URI
[in]	optnum	option number to use (e.g., COAP_OPT_URI_PATH)

Returns: amount of bytes written to buf

ssize_t coap_reply_simple	(	coap_pkt_t *	pkt,
		unsigned	code,
		uint8_t *	buf,
		size_t	len,
		unsigned	ct,
		const uint8_t *	payload,
		uint8_t	payload_len
	)

Create CoAP reply (convenience function)

This is a simple wrapper that allows for building CoAP replies for simple use-cases.

The reply will be written to buf. Is payload and payload_len non-zero, the payload will be copied into the resulting reply packet.

Parameters

[in]	pkt	packet to reply to
[in]	code	reply code (e.g., COAP_CODE_204)
[out]	buf	buffer to write reply to
[in]	len	size of `buf`
[in]	ct	content type of payload
[in]	payload	ptr to payload
[in]	payload_len	length of payload

Returns: size of reply packet on success; <0 on error

static unsigned coap_szx2size ( unsigned szx )

inlinestatic

Helper to decode SZX value to size in bytes.

Parameters

[in] szx SZX value to decode

Returns: SZX value decoded to bytes

Definition at line 618 of file nanocoap.h.

Detailed Description

Read Request

Write Response

Write Request

Write Options and Payload

Higher-level, struct-based API

Minimal, buffer-based API

Files

Data Structures

Macros

Typedefs

Functions

Variables

Nanocoap specific maximum values

CoAP option numbers

CoAP packet types

Message types -- confirmable, non-confirmable, etc.

CoAP method codes used in header

CoAP method flags used in coap_handlers array

Empty CoAP message code

Response message codes: success

Response message codes: client error

Response message codes: server error

Content types

Content-Format option codes

Observe (RFC 7641) constants

Timing parameters

Blockwise transfer (RFC7959)

Macro Definition Documentation

Function Documentation