CoAP

This module includes functions that control CoAP communication.

Summary

The functions in this module are available when CoAP API feature (OPENTHREAD_CONFIG_COAP_API_ENABLE) is enabled.

Enumerations

otCoapBlockSize enum
CoAP Block Size Exponents.
otCoapCode{
  OT_COAP_CODE_EMPTY = OT_COAP_CODE(0, 0),
  OT_COAP_CODE_GET = OT_COAP_CODE(0, 1),
  OT_COAP_CODE_POST = OT_COAP_CODE(0, 2),
  OT_COAP_CODE_PUT = OT_COAP_CODE(0, 3),
  OT_COAP_CODE_DELETE = OT_COAP_CODE(0, 4),
  OT_COAP_CODE_RESPONSE_MIN = OT_COAP_CODE(2, 0),
  OT_COAP_CODE_CREATED = OT_COAP_CODE(2, 1),
  OT_COAP_CODE_DELETED = OT_COAP_CODE(2, 2),
  OT_COAP_CODE_VALID = OT_COAP_CODE(2, 3),
  OT_COAP_CODE_CHANGED = OT_COAP_CODE(2, 4),
  OT_COAP_CODE_CONTENT = OT_COAP_CODE(2, 5),
  OT_COAP_CODE_CONTINUE = OT_COAP_CODE(2, 31),
  OT_COAP_CODE_BAD_REQUEST = OT_COAP_CODE(4, 0),
  OT_COAP_CODE_UNAUTHORIZED = OT_COAP_CODE(4, 1),
  OT_COAP_CODE_BAD_OPTION = OT_COAP_CODE(4, 2),
  OT_COAP_CODE_FORBIDDEN = OT_COAP_CODE(4, 3),
  OT_COAP_CODE_NOT_FOUND = OT_COAP_CODE(4, 4),
  OT_COAP_CODE_METHOD_NOT_ALLOWED = OT_COAP_CODE(4, 5),
  OT_COAP_CODE_NOT_ACCEPTABLE = OT_COAP_CODE(4, 6),
  OT_COAP_CODE_REQUEST_INCOMPLETE = OT_COAP_CODE(4, 8),
  OT_COAP_CODE_PRECONDITION_FAILED = OT_COAP_CODE(4, 12),
  OT_COAP_CODE_REQUEST_TOO_LARGE = OT_COAP_CODE(4, 13),
  OT_COAP_CODE_UNSUPPORTED_FORMAT = OT_COAP_CODE(4, 15),
  OT_COAP_CODE_INTERNAL_ERROR = OT_COAP_CODE(5, 0),
  OT_COAP_CODE_NOT_IMPLEMENTED = OT_COAP_CODE(5, 1),
  OT_COAP_CODE_BAD_GATEWAY = OT_COAP_CODE(5, 2),
  OT_COAP_CODE_SERVICE_UNAVAILABLE = OT_COAP_CODE(5, 3),
  OT_COAP_CODE_GATEWAY_TIMEOUT = OT_COAP_CODE(5, 4),
  OT_COAP_CODE_PROXY_NOT_SUPPORTED = OT_COAP_CODE(5, 5)
}
enum
CoAP Code values.
otCoapOptionContentFormat{
  OT_COAP_OPTION_CONTENT_FORMAT_TEXT_PLAIN = 0,
  OT_COAP_OPTION_CONTENT_FORMAT_COSE_ENCRYPT0 = 16,
  OT_COAP_OPTION_CONTENT_FORMAT_COSE_MAC0 = 17,
  OT_COAP_OPTION_CONTENT_FORMAT_COSE_SIGN1 = 18,
  OT_COAP_OPTION_CONTENT_FORMAT_LINK_FORMAT = 40,
  OT_COAP_OPTION_CONTENT_FORMAT_XML = 41,
  OT_COAP_OPTION_CONTENT_FORMAT_OCTET_STREAM = 42,
  OT_COAP_OPTION_CONTENT_FORMAT_EXI = 47,
  OT_COAP_OPTION_CONTENT_FORMAT_JSON = 50,
  OT_COAP_OPTION_CONTENT_FORMAT_JSON_PATCH_JSON = 51,
  OT_COAP_OPTION_CONTENT_FORMAT_MERGE_PATCH_JSON = 52,
  OT_COAP_OPTION_CONTENT_FORMAT_CBOR = 60,
  OT_COAP_OPTION_CONTENT_FORMAT_CWT = 61,
  OT_COAP_OPTION_CONTENT_FORMAT_COSE_ENCRYPT = 96,
  OT_COAP_OPTION_CONTENT_FORMAT_COSE_MAC = 97,
  OT_COAP_OPTION_CONTENT_FORMAT_COSE_SIGN = 98,
  OT_COAP_OPTION_CONTENT_FORMAT_COSE_KEY = 101,
  OT_COAP_OPTION_CONTENT_FORMAT_COSE_KEY_SET = 102,
  OT_COAP_OPTION_CONTENT_FORMAT_SENML_JSON = 110,
  OT_COAP_OPTION_CONTENT_FORMAT_SENSML_JSON = 111,
  OT_COAP_OPTION_CONTENT_FORMAT_SENML_CBOR = 112,
  OT_COAP_OPTION_CONTENT_FORMAT_SENSML_CBOR = 113,
  OT_COAP_OPTION_CONTENT_FORMAT_SENML_EXI = 114,
  OT_COAP_OPTION_CONTENT_FORMAT_SENSML_EXI = 115,
  OT_COAP_OPTION_CONTENT_FORMAT_COAP_GROUP_JSON = 256,
  OT_COAP_OPTION_CONTENT_FORMAT_SENML_XML = 310,
  OT_COAP_OPTION_CONTENT_FORMAT_SENSML_XML = 311
}
enum
CoAP Content Format codes.
otCoapOptionType{
  OT_COAP_OPTION_IF_MATCH = 1,
  OT_COAP_OPTION_URI_HOST = 3,
  OT_COAP_OPTION_E_TAG = 4,
  OT_COAP_OPTION_IF_NONE_MATCH = 5,
  OT_COAP_OPTION_OBSERVE = 6,
  OT_COAP_OPTION_URI_PORT = 7,
  OT_COAP_OPTION_LOCATION_PATH = 8,
  OT_COAP_OPTION_URI_PATH = 11,
  OT_COAP_OPTION_CONTENT_FORMAT = 12,
  OT_COAP_OPTION_MAX_AGE = 14,
  OT_COAP_OPTION_URI_QUERY = 15,
  OT_COAP_OPTION_ACCEPT = 17,
  OT_COAP_OPTION_LOCATION_QUERY = 20,
  OT_COAP_OPTION_BLOCK2 = 23,
  OT_COAP_OPTION_BLOCK1 = 27,
  OT_COAP_OPTION_PROXY_URI = 35,
  OT_COAP_OPTION_PROXY_SCHEME = 39,
  OT_COAP_OPTION_SIZE1 = 60
}
enum
CoAP Option Numbers.
otCoapType{
  OT_COAP_TYPE_CONFIRMABLE = 0x00,
  OT_COAP_TYPE_NON_CONFIRMABLE = 0x10,
  OT_COAP_TYPE_ACKNOWLEDGMENT = 0x20,
  OT_COAP_TYPE_RESET = 0x30
}
enum
CoAP Type values.

Typedefs

otCoapBlockSize typedef
CoAP Block Size Exponents.
otCoapCode typedef
enum otCoapCode
CoAP Code values.
otCoapOption typedef
struct otCoapOption
This structure represents a CoAP option.
otCoapOptionContentFormat typedef
CoAP Content Format codes.
otCoapOptionIterator typedef
This structure acts as an iterator for CoAP options.
otCoapOptionType typedef
CoAP Option Numbers.
otCoapRequestHandler)(void *aContext, otMessage *aMessage, const otMessageInfo *aMessageInfo) typedef
void(*
This function pointer is called when a CoAP request with a given Uri-Path is received.
otCoapResource typedef
This structure represents a CoAP resource.
otCoapResponseHandler)(void *aContext, otMessage *aMessage, const otMessageInfo *aMessageInfo, otError aResult) typedef
void(*
This function pointer is called when a CoAP response is received or on the request timeout.
otCoapTxParameters typedef
This structure represents the CoAP transmission parameters.
otCoapType typedef
enum otCoapType
CoAP Type values.

Functions

otCoapAddResource(otInstance *aInstance, otCoapResource *aResource)
This function adds a resource to the CoAP server.
otCoapBlockSizeFromExponent(otCoapBlockSize aSize)
uint16_t
This function converts a CoAP Block option SZX field to the actual block size.
otCoapMessageAppendBlock1Option(otMessage *aMessage, uint32_t aNum, bool aMore, otCoapBlockSize aSize)
This function appends a Block1 option.
otCoapMessageAppendBlock2Option(otMessage *aMessage, uint32_t aNum, bool aMore, otCoapBlockSize aSize)
This function appends a Block2 option.
otCoapMessageAppendContentFormatOption(otMessage *aMessage, otCoapOptionContentFormat aContentFormat)
This function appends the Content Format CoAP option as specified in https://tools.ietf.org/html/rfc7252#page-92.
otCoapMessageAppendMaxAgeOption(otMessage *aMessage, uint32_t aMaxAge)
This function appends a Max-Age option.
otCoapMessageAppendObserveOption(otMessage *aMessage, uint32_t aObserve)
This function appends an Observe option.
otCoapMessageAppendOption(otMessage *aMessage, uint16_t aNumber, uint16_t aLength, const void *aValue)
This function appends a CoAP option in a header.
otCoapMessageAppendProxyUriOption(otMessage *aMessage, const char *aUriPath)
This function appends a Proxy-Uri option.
otCoapMessageAppendUintOption(otMessage *aMessage, uint16_t aNumber, uint32_t aValue)
This function appends an unsigned integer CoAP option as specified in https://tools.ietf.org/html/rfc7252#section-3.2.
otCoapMessageAppendUriPathOptions(otMessage *aMessage, const char *aUriPath)
This function appends a Uri-Path option.
otCoapMessageAppendUriQueryOption(otMessage *aMessage, const char *aUriQuery)
This function appends a single Uri-Query option.
otCoapMessageCodeToString(const otMessage *aMessage)
const char *
This method returns the CoAP Code as human readable string.
otCoapMessageGenerateToken(otMessage *aMessage, uint8_t aTokenLength)
void
This function sets the Token length and randomizes its value.
otCoapMessageGetCode(const otMessage *aMessage)
This function returns the Code value.
otCoapMessageGetMessageId(const otMessage *aMessage)
uint16_t
This function returns the Message ID value.
otCoapMessageGetToken(const otMessage *aMessage)
const uint8_t *
This function returns a pointer to the Token value.
otCoapMessageGetTokenLength(const otMessage *aMessage)
uint8_t
This function returns the Token length.
otCoapMessageGetType(const otMessage *aMessage)
This function returns the Type value.
otCoapMessageInit(otMessage *aMessage, otCoapType aType, otCoapCode aCode)
void
This function initializes the CoAP header.
otCoapMessageInitResponse(otMessage *aResponse, const otMessage *aRequest, otCoapType aType, otCoapCode aCode)
This function initializes a response message.
otCoapMessageSetPayloadMarker(otMessage *aMessage)
This function adds Payload Marker indicating beginning of the payload to the CoAP header.
otCoapMessageSetToken(otMessage *aMessage, const uint8_t *aToken, uint8_t aTokenLength)
This function sets the Token value and length in a header.
otCoapNewMessage(otInstance *aInstance, const otMessageSettings *aSettings)
This function creates a new CoAP message.
otCoapOptionIteratorGetFirstOption(otCoapOptionIterator *aIterator)
const otCoapOption *
This function returns a pointer to the first option.
otCoapOptionIteratorGetFirstOptionMatching(otCoapOptionIterator *aIterator, uint16_t aOption)
const otCoapOption *
This function returns a pointer to the first option matching the specified option number.
otCoapOptionIteratorGetNextOption(otCoapOptionIterator *aIterator)
const otCoapOption *
This function returns a pointer to the next option.
otCoapOptionIteratorGetNextOptionMatching(otCoapOptionIterator *aIterator, uint16_t aOption)
const otCoapOption *
This function returns a pointer to the next option matching the specified option number.
otCoapOptionIteratorGetOptionUintValue(otCoapOptionIterator *aIterator, uint64_t *const aValue)
This function fills current option value into aValue assuming the current value is an unsigned integer encoded according to https://tools.ietf.org/html/rfc7252#section-3.2.
otCoapOptionIteratorGetOptionValue(otCoapOptionIterator *aIterator, void *aValue)
This function fills current option value into aValue.
otCoapOptionIteratorInit(otCoapOptionIterator *aIterator, const otMessage *aMessage)
This function initialises an iterator for the options in the given message.
otCoapRemoveResource(otInstance *aInstance, otCoapResource *aResource)
void
This function removes a resource from the CoAP server.
otCoapSendRequest(otInstance *aInstance, otMessage *aMessage, const otMessageInfo *aMessageInfo, otCoapResponseHandler aHandler, void *aContext)
This function sends a CoAP request.
otCoapSendRequestWithParameters(otInstance *aInstance, otMessage *aMessage, const otMessageInfo *aMessageInfo, otCoapResponseHandler aHandler, void *aContext, const otCoapTxParameters *aTxParameters)
This function sends a CoAP request with custom transmission parameters.
otCoapSendResponse(otInstance *aInstance, otMessage *aMessage, const otMessageInfo *aMessageInfo)
This function sends a CoAP response from the server.
otCoapSendResponseWithParameters(otInstance *aInstance, otMessage *aMessage, const otMessageInfo *aMessageInfo, const otCoapTxParameters *aTxParameters)
This function sends a CoAP response from the server with custom transmission parameters.
otCoapSetDefaultHandler(otInstance *aInstance, otCoapRequestHandler aHandler, void *aContext)
void
This function sets the default handler for unhandled CoAP requests.
otCoapStart(otInstance *aInstance, uint16_t aPort)
This function starts the CoAP server.
otCoapStop(otInstance *aInstance)
This function stops the CoAP server.

Structs

otCoapOption

This structure represents a CoAP option.

otCoapOptionIterator

This structure acts as an iterator for CoAP options.

otCoapResource

This structure represents a CoAP resource.

otCoapTxParameters

This structure represents the CoAP transmission parameters.

Enumerations

otCoapBlockSize

 otCoapBlockSize

CoAP Block Size Exponents.

otCoapOptionContentFormat

 otCoapOptionContentFormat

CoAP Content Format codes.

The full list is documented at https://www.iana.org/assignments/core-parameters/core-parameters.xhtml#content-formats

Properties
OT_COAP_OPTION_CONTENT_FORMAT_CBOR

application/cbor: [RFC7049]

OT_COAP_OPTION_CONTENT_FORMAT_COAP_GROUP_JSON

application/coap-group+json: [RFC7390]

OT_COAP_OPTION_CONTENT_FORMAT_COSE_ENCRYPT

application/cose; cose-type="cose-encrypt": [RFC8152]

OT_COAP_OPTION_CONTENT_FORMAT_COSE_ENCRYPT0

application/cose; cose-type="cose-encrypt0": [RFC8152]

OT_COAP_OPTION_CONTENT_FORMAT_COSE_KEY

application/cose-key: [RFC8152]

OT_COAP_OPTION_CONTENT_FORMAT_COSE_KEY_SET

application/cose-key-set: [RFC8152]

OT_COAP_OPTION_CONTENT_FORMAT_COSE_MAC

application/cose; cose-type="cose-mac": [RFC8152]

OT_COAP_OPTION_CONTENT_FORMAT_COSE_MAC0

application/cose; cose-type="cose-mac0": [RFC8152]

OT_COAP_OPTION_CONTENT_FORMAT_COSE_SIGN

application/cose; cose-type="cose-sign": [RFC8152]

OT_COAP_OPTION_CONTENT_FORMAT_COSE_SIGN1

application/cose; cose-type="cose-sign1": [RFC8152]

OT_COAP_OPTION_CONTENT_FORMAT_CWT

application/cwt: [RFC8392]

OT_COAP_OPTION_CONTENT_FORMAT_EXI

application/exi: ["Efficient XML Interchange (EXI) Format 1.0 (Second Edition)", February 2014]

OT_COAP_OPTION_CONTENT_FORMAT_JSON

application/json: [RFC7159]

OT_COAP_OPTION_CONTENT_FORMAT_JSON_PATCH_JSON

application/json-patch+json: [RFC6902]

OT_COAP_OPTION_CONTENT_FORMAT_LINK_FORMAT

application/link-format: [RFC6690]

OT_COAP_OPTION_CONTENT_FORMAT_MERGE_PATCH_JSON

application/merge-patch+json: [RFC7396]

OT_COAP_OPTION_CONTENT_FORMAT_OCTET_STREAM

application/octet-stream: [RFC2045][RFC2046]

OT_COAP_OPTION_CONTENT_FORMAT_SENML_CBOR

application/senml+cbor: [RFC8428]

OT_COAP_OPTION_CONTENT_FORMAT_SENML_EXI

application/senml-exi: [RFC8428]

OT_COAP_OPTION_CONTENT_FORMAT_SENML_JSON

application/senml+json: [RFC8428]

OT_COAP_OPTION_CONTENT_FORMAT_SENML_XML

application/senml+xml: [RFC8428]

OT_COAP_OPTION_CONTENT_FORMAT_SENSML_CBOR

application/sensml+cbor: [RFC8428]

OT_COAP_OPTION_CONTENT_FORMAT_SENSML_EXI

application/sensml-exi: [RFC8428]

OT_COAP_OPTION_CONTENT_FORMAT_SENSML_JSON

application/sensml+json: [RFC8428]

OT_COAP_OPTION_CONTENT_FORMAT_SENSML_XML

application/sensml+xml: [RFC8428]

OT_COAP_OPTION_CONTENT_FORMAT_TEXT_PLAIN

text/plain; charset=utf-8: [RFC2046][RFC3676][RFC5147]

OT_COAP_OPTION_CONTENT_FORMAT_XML

application/xml: [RFC3023]

otCoapType

 otCoapType

CoAP Type values.

Properties
OT_COAP_TYPE_ACKNOWLEDGMENT

Acknowledgment.

OT_COAP_TYPE_CONFIRMABLE

Confirmable.

OT_COAP_TYPE_NON_CONFIRMABLE

Non-confirmable.

OT_COAP_TYPE_RESET

Reset.

Typedefs

otCoapBlockSize

enum otCoapBlockSize otCoapBlockSize

CoAP Block Size Exponents.

otCoapCode

enum otCoapCode otCoapCode

CoAP Code values.

otCoapOption

struct otCoapOption otCoapOption

This structure represents a CoAP option.

otCoapOptionContentFormat

enum otCoapOptionContentFormat otCoapOptionContentFormat

CoAP Content Format codes.

The full list is documented at https://www.iana.org/assignments/core-parameters/core-parameters.xhtml#content-formats

otCoapOptionIterator

struct otCoapOptionIterator otCoapOptionIterator

This structure acts as an iterator for CoAP options.

otCoapOptionType

enum otCoapOptionType otCoapOptionType

CoAP Option Numbers.

otCoapRequestHandler

void(* otCoapRequestHandler)(void *aContext, otMessage *aMessage, const otMessageInfo *aMessageInfo)

This function pointer is called when a CoAP request with a given Uri-Path is received.

Details
Parameters
[in] aContext
A pointer to arbitrary context information.
[in] aMessage
A pointer to the message.
[in] aMessageInfo
A pointer to the message info for aMessage.

otCoapResource

struct otCoapResource otCoapResource

This structure represents a CoAP resource.

otCoapResponseHandler

void(* otCoapResponseHandler)(void *aContext, otMessage *aMessage, const otMessageInfo *aMessageInfo, otError aResult)

This function pointer is called when a CoAP response is received or on the request timeout.

Details
Parameters
[in] aContext
A pointer to application-specific context.
[in] aMessage
A pointer to the message buffer containing the response. NULL if no response was received.
[in] aMessageInfo
A pointer to the message info for aMessage. NULL if no response was received.
[in] aResult
A result of the CoAP transaction.
Return Values
OT_ERROR_NONE
A response was received successfully.
OT_ERROR_ABORT
A CoAP transaction was reset by peer.
OT_ERROR_RESPONSE_TIMEOUT
No response or acknowledgment received during timeout period.

otCoapTxParameters

struct otCoapTxParameters otCoapTxParameters

This structure represents the CoAP transmission parameters.

otCoapType

enum otCoapType otCoapType

CoAP Type values.

Functions

otCoapAddResource

otError otCoapAddResource(
  otInstance *aInstance,
  otCoapResource *aResource
)

This function adds a resource to the CoAP server.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[in] aResource
A pointer to the resource.
Return Values
OT_ERROR_NONE
Successfully added aResource.
OT_ERROR_ALREADY
The aResource was already added.

otCoapBlockSizeFromExponent

uint16_t otCoapBlockSizeFromExponent(
  otCoapBlockSize aSize
)

This function converts a CoAP Block option SZX field to the actual block size.

Details
Parameters
[in] aSize
Block size exponent.
Returns
The actual size exponent value.

otCoapMessageAppendBlock1Option

otError otCoapMessageAppendBlock1Option(
  otMessage *aMessage,
  uint32_t aNum,
  bool aMore,
  otCoapBlockSize aSize
)

This function appends a Block1 option.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
[in] aNum
Current block number.
[in] aMore
Boolean to indicate more blocks are to be sent.
[in] aSize
Block Size Exponent.
Return Values
OT_ERROR_NONE
Successfully appended the option.
OT_ERROR_INVALID_ARGS
The option type is not equal or greater than the last option type.
OT_ERROR_NO_BUFS
The option length exceeds the buffer size.

otCoapMessageAppendBlock2Option

otError otCoapMessageAppendBlock2Option(
  otMessage *aMessage,
  uint32_t aNum,
  bool aMore,
  otCoapBlockSize aSize
)

This function appends a Block2 option.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
[in] aNum
Current block number.
[in] aMore
Boolean to indicate more blocks are to be sent.
[in] aSize
Block Size Exponent.
Return Values
OT_ERROR_NONE
Successfully appended the option.
OT_ERROR_INVALID_ARGS
The option type is not equal or greater than the last option type.
OT_ERROR_NO_BUFS
The option length exceeds the buffer size.

otCoapMessageAppendContentFormatOption

otError otCoapMessageAppendContentFormatOption(
  otMessage *aMessage,
  otCoapOptionContentFormat aContentFormat
)

This function appends the Content Format CoAP option as specified in https://tools.ietf.org/html/rfc7252#page-92.

This must be called before setting otCoapMessageSetPayloadMarker if a payload is to be included in the message.

The function is a convenience wrapper around otCoapMessageAppendUintOption, and if the desired format type code isn't listed in otCoapOptionContentFormat, this base function should be used instead.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
[in] aContentFormat
One of the content formats listed in otCoapOptionContentFormat above.
Return Values
OT_ERROR_NONE
Successfully appended the option.
OT_ERROR_INVALID_ARGS
The option type is not equal or greater than the last option type.
OT_ERROR_NO_BUFS
The option length exceeds the buffer size.

otCoapMessageAppendMaxAgeOption

otError otCoapMessageAppendMaxAgeOption(
  otMessage *aMessage,
  uint32_t aMaxAge
)

This function appends a Max-Age option.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
[in] aMaxAge
The Max-Age value.
Return Values
OT_ERROR_NONE
Successfully appended the option.
OT_ERROR_INVALID_ARGS
The option type is not equal or greater than the last option type.
OT_ERROR_NO_BUFS
The option length exceeds the buffer size.

otCoapMessageAppendObserveOption

otError otCoapMessageAppendObserveOption(
  otMessage *aMessage,
  uint32_t aObserve
)

This function appends an Observe option.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
[in] aObserve
Observe field value.
Return Values
OT_ERROR_NONE
Successfully appended the option.
OT_ERROR_INVALID_ARGS
The option type is not equal or greater than the last option type.
OT_ERROR_NO_BUFS
The option length exceeds the buffer size.

otCoapMessageAppendOption

otError otCoapMessageAppendOption(
  otMessage *aMessage,
  uint16_t aNumber,
  uint16_t aLength,
  const void *aValue
)

This function appends a CoAP option in a header.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
[in] aNumber
The CoAP Option number.
[in] aLength
The CoAP Option length.
[in] aValue
A pointer to the CoAP value.
Return Values
OT_ERROR_NONE
Successfully appended the option.
OT_ERROR_INVALID_ARGS
The option type is not equal or greater than the last option type.
OT_ERROR_NO_BUFS
The option length exceeds the buffer size.

otCoapMessageAppendProxyUriOption

otError otCoapMessageAppendProxyUriOption(
  otMessage *aMessage,
  const char *aUriPath
)

This function appends a Proxy-Uri option.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
[in] aUriPath
A pointer to a NULL-terminated string.
Return Values
OT_ERROR_NONE
Successfully appended the option.
OT_ERROR_INVALID_ARGS
The option type is not equal or greater than the last option type.
OT_ERROR_NO_BUFS
The option length exceeds the buffer size.

otCoapMessageAppendUintOption

otError otCoapMessageAppendUintOption(
  otMessage *aMessage,
  uint16_t aNumber,
  uint32_t aValue
)

This function appends an unsigned integer CoAP option as specified in https://tools.ietf.org/html/rfc7252#section-3.2.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
[in] aNumber
The CoAP Option number.
[in] aValue
The CoAP Option unsigned integer value.
Return Values
OT_ERROR_NONE
Successfully appended the option.
OT_ERROR_INVALID_ARGS
The option type is not equal or greater than the last option type.
OT_ERROR_NO_BUFS
The option length exceeds the buffer size.
See also:
otCoapMessageGetOptionUintValue

otCoapMessageAppendUriPathOptions

otError otCoapMessageAppendUriPathOptions(
  otMessage *aMessage,
  const char *aUriPath
)

This function appends a Uri-Path option.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
[in] aUriPath
A pointer to a NULL-terminated string.
Return Values
OT_ERROR_NONE
Successfully appended the option.
OT_ERROR_INVALID_ARGS
The option type is not equal or greater than the last option type.
OT_ERROR_NO_BUFS
The option length exceeds the buffer size.

otCoapMessageAppendUriQueryOption

otError otCoapMessageAppendUriQueryOption(
  otMessage *aMessage,
  const char *aUriQuery
)

This function appends a single Uri-Query option.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
[in] aUriQuery
A pointer to NULL-terminated string, which should contain a single key=value pair.
Return Values
OT_ERROR_NONE
Successfully appended the option.
OT_ERROR_INVALID_ARGS
The option type is not equal or greater than the last option type.
OT_ERROR_NO_BUFS
The option length exceeds the buffer size.

otCoapMessageCodeToString

const char * otCoapMessageCodeToString(
  const otMessage *aMessage
)

This method returns the CoAP Code as human readable string.

@ returns The CoAP Code as string.

Details
Parameters
[in] aMessage
A pointer to the CoAP message.

otCoapMessageGenerateToken

void otCoapMessageGenerateToken(
  otMessage *aMessage,
  uint8_t aTokenLength
)

This function sets the Token length and randomizes its value.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
[in] aTokenLength
The Length of a Token to set.

otCoapMessageGetCode

otCoapCode otCoapMessageGetCode(
  const otMessage *aMessage
)

This function returns the Code value.

Details
Parameters
[in] aMessage
A pointer to the CoAP message.
Returns
The Code value.

otCoapMessageGetMessageId

uint16_t otCoapMessageGetMessageId(
  const otMessage *aMessage
)

This function returns the Message ID value.

Details
Parameters
[in] aMessage
A pointer to the CoAP message.
Returns
The Message ID value.

otCoapMessageGetToken

const uint8_t * otCoapMessageGetToken(
  const otMessage *aMessage
)

This function returns a pointer to the Token value.

Details
Parameters
[in] aMessage
A pointer to the CoAP message.
Returns
A pointer to the Token value.

otCoapMessageGetTokenLength

uint8_t otCoapMessageGetTokenLength(
  const otMessage *aMessage
)

This function returns the Token length.

Details
Parameters
[in] aMessage
A pointer to the CoAP message.
Returns
The Token length.

otCoapMessageGetType

otCoapType otCoapMessageGetType(
  const otMessage *aMessage
)

This function returns the Type value.

Details
Parameters
[in] aMessage
A pointer to the CoAP message.
Returns
The Type value.

otCoapMessageInit

void otCoapMessageInit(
  otMessage *aMessage,
  otCoapType aType,
  otCoapCode aCode
)

This function initializes the CoAP header.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message to initialize.
[in] aType
CoAP message type.
[in] aCode
CoAP message code.

otCoapMessageInitResponse

otError otCoapMessageInitResponse(
  otMessage *aResponse,
  const otMessage *aRequest,
  otCoapType aType,
  otCoapCode aCode
)

This function initializes a response message.

Details
Parameters
[in,out] aResponse
A pointer to the CoAP response message.
[in] aRequest
A pointer to the CoAP request message.
[in] aType
CoAP message type.
[in] aCode
CoAP message code.
Return Values
OT_ERROR_NONE
Successfully initialized the response message.
OT_ERROR_NO_BUFS
Insufficient message buffers available to initialize the response message.

otCoapMessageSetPayloadMarker

otError otCoapMessageSetPayloadMarker(
  otMessage *aMessage
)

This function adds Payload Marker indicating beginning of the payload to the CoAP header.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
Return Values
OT_ERROR_NONE
Payload Marker successfully added.
OT_ERROR_NO_BUFS
Header Payload Marker exceeds the buffer size.

otCoapMessageSetToken

otError otCoapMessageSetToken(
  otMessage *aMessage,
  const uint8_t *aToken,
  uint8_t aTokenLength
)

This function sets the Token value and length in a header.

Details
Parameters
[in,out] aMessage
A pointer to the CoAP message.
[in] aToken
A pointer to the Token value.
[in] aTokenLength
The Length of aToken.
Return Values
OT_ERROR_NONE
Successfully set the Token value.
OT_ERROR_NO_BUFS
Insufficient buffers to set the Token value.

otCoapNewMessage

otMessage * otCoapNewMessage(
  otInstance *aInstance,
  const otMessageSettings *aSettings
)

This function creates a new CoAP message.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[in] aSettings
A pointer to the message settings or NULL to set default settings.
Returns
A pointer to the message buffer or NULL if no message buffers are available or parameters are invalid.

otCoapOptionIteratorGetFirstOption

const otCoapOption * otCoapOptionIteratorGetFirstOption(
  otCoapOptionIterator *aIterator
)

This function returns a pointer to the first option.

Details
Parameters
[in,out] aIterator
A pointer to the CoAP message option iterator.
Returns
A pointer to the first option. If no option is present NULL pointer is returned.

otCoapOptionIteratorGetFirstOptionMatching

const otCoapOption * otCoapOptionIteratorGetFirstOptionMatching(
  otCoapOptionIterator *aIterator,
  uint16_t aOption
)

This function returns a pointer to the first option matching the specified option number.

Details
Parameters
[in] aIterator
A pointer to the CoAP message option iterator.
[in] aOption
The option number sought.
Returns
A pointer to the first matching option. If no matching option is present NULL pointer is returned.

otCoapOptionIteratorGetNextOption

const otCoapOption * otCoapOptionIteratorGetNextOption(
  otCoapOptionIterator *aIterator
)

This function returns a pointer to the next option.

Details
Parameters
[in,out] aIterator
A pointer to the CoAP message option iterator.
Returns
A pointer to the next option. If no more options are present NULL pointer is returned.

otCoapOptionIteratorGetNextOptionMatching

const otCoapOption * otCoapOptionIteratorGetNextOptionMatching(
  otCoapOptionIterator *aIterator,
  uint16_t aOption
)

This function returns a pointer to the next option matching the specified option number.

Details
Parameters
[in] aIterator
A pointer to the CoAP message option iterator.
[in] aOption
The option number sought.
Returns
A pointer to the next matching option. If no further matching option is present NULL pointer is returned.

otCoapOptionIteratorGetOptionUintValue

otError otCoapOptionIteratorGetOptionUintValue(
  otCoapOptionIterator *aIterator,
  uint64_t *const aValue
)

This function fills current option value into aValue assuming the current value is an unsigned integer encoded according to https://tools.ietf.org/html/rfc7252#section-3.2.

Details
Parameters
[in,out] aIterator
A pointer to the CoAP message option iterator.
[out] aValue
A pointer to an unsigned integer to receive the option value.
Return Values
OT_ERROR_NONE
Successfully filled value.
OT_ERROR_NOT_FOUND
No current option.
OT_ERROR_NO_BUFS
Value is too long to fit in a uint64_t.
See also:
otCoapMessageAppendUintOption

otCoapOptionIteratorGetOptionValue

otError otCoapOptionIteratorGetOptionValue(
  otCoapOptionIterator *aIterator,
  void *aValue
)

This function fills current option value into aValue.

Details
Parameters
[in,out] aIterator
A pointer to the CoAP message option iterator.
[out] aValue
A pointer to a buffer to receive the option value.
Return Values
OT_ERROR_NONE
Successfully filled value.
OT_ERROR_NOT_FOUND
No current option.

otCoapOptionIteratorInit

otError otCoapOptionIteratorInit(
  otCoapOptionIterator *aIterator,
  const otMessage *aMessage
)

This function initialises an iterator for the options in the given message.

Details
Parameters
[in,out] aIterator
A pointer to the CoAP message option iterator.
[in] aMessage
A pointer to the CoAP message.
Return Values
OT_ERROR_NONE
Successfully initialised.
OT_ERROR_PARSE
Message state is inconsistent.

otCoapRemoveResource

void otCoapRemoveResource(
  otInstance *aInstance,
  otCoapResource *aResource
)

This function removes a resource from the CoAP server.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[in] aResource
A pointer to the resource.

otCoapSendRequest

otError otCoapSendRequest(
  otInstance *aInstance,
  otMessage *aMessage,
  const otMessageInfo *aMessageInfo,
  otCoapResponseHandler aHandler,
  void *aContext
)

This function sends a CoAP request.

If a response for a request is expected, respective function and context information should be provided. If no response is expected, these arguments should be NULL pointers.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[in] aMessage
A pointer to the message to send.
[in] aMessageInfo
A pointer to the message info associated with aMessage.
[in] aHandler
A function pointer that shall be called on response reception or timeout.
[in] aContext
A pointer to arbitrary context information. May be NULL if not used.
Return Values
OT_ERROR_NONE
Successfully sent CoAP message.
OT_ERROR_NO_BUFS
Failed to allocate retransmission data.

otCoapSendRequestWithParameters

otError otCoapSendRequestWithParameters(
  otInstance *aInstance,
  otMessage *aMessage,
  const otMessageInfo *aMessageInfo,
  otCoapResponseHandler aHandler,
  void *aContext,
  const otCoapTxParameters *aTxParameters
)

This function sends a CoAP request with custom transmission parameters.

If a response for a request is expected, respective function and context information should be provided. If no response is expected, these arguments should be NULL pointers.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[in] aMessage
A pointer to the message to send.
[in] aMessageInfo
A pointer to the message info associated with aMessage.
[in] aHandler
A function pointer that shall be called on response reception or timeout.
[in] aContext
A pointer to arbitrary context information. May be NULL if not used.
[in] aTxParameters
A pointer to transmission parameters for this request. Use NULL for defaults. Otherwise, parameters given must meet the following conditions:
  1. mMaxRetransmit is no more than OT_COAP_MAX_RETRANSMIT.
  2. mAckRandomFactorNumerator / mAckRandomFactorDenominator must not be below 1.0.
  3. The calculated exchange life time must not overflow uint32_t.
Return Values
OT_ERROR_INVALID_ARGS
aTxParameters is invalid.
OT_ERROR_NONE
Successfully sent CoAP message.
OT_ERROR_NO_BUFS
Failed to allocate retransmission data.

otCoapSendResponse

otError otCoapSendResponse(
  otInstance *aInstance,
  otMessage *aMessage,
  const otMessageInfo *aMessageInfo
)

This function sends a CoAP response from the server.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[in] aMessage
A pointer to the CoAP response to send.
[in] aMessageInfo
A pointer to the message info associated with aMessage.
Return Values
OT_ERROR_NONE
Successfully enqueued the CoAP response message.
OT_ERROR_NO_BUFS
Insufficient buffers available to send the CoAP response.

otCoapSendResponseWithParameters

otError otCoapSendResponseWithParameters(
  otInstance *aInstance,
  otMessage *aMessage,
  const otMessageInfo *aMessageInfo,
  const otCoapTxParameters *aTxParameters
)

This function sends a CoAP response from the server with custom transmission parameters.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[in] aMessage
A pointer to the CoAP response to send.
[in] aMessageInfo
A pointer to the message info associated with aMessage.
[in] aTxParameters
A pointer to transmission parameters for this response. Use NULL for defaults.
Return Values
OT_ERROR_NONE
Successfully enqueued the CoAP response message.
OT_ERROR_NO_BUFS
Insufficient buffers available to send the CoAP response.

otCoapSetDefaultHandler

void otCoapSetDefaultHandler(
  otInstance *aInstance,
  otCoapRequestHandler aHandler,
  void *aContext
)

This function sets the default handler for unhandled CoAP requests.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[in] aHandler
A function pointer that shall be called when an unhandled request arrives.
[in] aContext
A pointer to arbitrary context information. May be NULL if not used.

otCoapStart

otError otCoapStart(
  otInstance *aInstance,
  uint16_t aPort
)

This function starts the CoAP server.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[in] aPort
The local UDP port to bind to.
Return Values
OT_ERROR_NONE
Successfully started the CoAP server.

otCoapStop

otError otCoapStop(
  otInstance *aInstance
)

This function stops the CoAP server.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
Return Values
OT_ERROR_NONE
Successfully stopped the CoAP server.

Macros

OT_COAP_CODE

 OT_COAP_CODE ((((c)&0x7) << 5) | ((d)&0x1f))

Helper macro to define CoAP Code values.

OT_COAP_MAX_RETRANSMIT

 OT_COAP_MAX_RETRANSMIT 30

Max retransmit supported by OpenThread.

OT_COAP_MAX_TOKEN_LENGTH

 OT_COAP_MAX_TOKEN_LENGTH 8

Max token length as specified (RFC 7252).

OT_COAP_MIN_ACK_TIMEOUT

 OT_COAP_MIN_ACK_TIMEOUT 1000

Minimal ACK timeout in milliseconds supported by OpenThread.

OT_DEFAULT_COAP_PORT

 OT_DEFAULT_COAP_PORT 5683

Default CoAP port, as specified in RFC 7252.