CoAP TCP client API. More...

Data Structures
union	coap_client_tcp_event_data
	Event data for CoAP TCP signaling events. More...
struct	coap_client_tcp_option
	Representation of extra options for the CoAP TCP client request. More...
struct	coap_client_tcp_request
	Representation of a CoAP TCP client request. More...

Macros
#define	MAX_COAP_TCP_MSG_LEN
	Maximum size of a CoAP TCP message.

Typedefs
typedef void(*	coap_client_tcp_response_cb_t) (const struct coap_client_response_data data, void user_data)
	Callback for CoAP TCP request.
typedef int(*	coap_client_tcp_payload_cb_t) (size_t offset, const uint8_t *payload, size_t len, bool last_block, void user_data)
	Callback for providing a payload for the CoAP TCP request.
typedef int(*	coap_client_tcp_socket_config_cb_t) (int fd, void *user_data)
	Callback to configure the socket before connecting.
typedef void(*	coap_client_tcp_event_cb_t) (struct coap_client_tcp client, enum coap_client_tcp_event event, const union coap_client_tcp_event_data data, void *user_data)
	Callback for CoAP TCP signaling events (Release/Abort).

Enumerations
enum	coap_client_tcp_event { COAP_CLIENT_TCP_EVENT_CSM_UPDATED , COAP_CLIENT_TCP_EVENT_PONG_RECEIVED , COAP_CLIENT_TCP_EVENT_RELEASE , COAP_CLIENT_TCP_EVENT_ABORT }
	CoAP TCP client event types for signaling. More...

Functions
int	coap_client_tcp_init (struct coap_client_tcp client, const char info)
	Initialize the TCP CoAP client.
int	coap_client_tcp_connect (struct coap_client_tcp client, const struct net_sockaddr addr, net_socklen_t addrlen, int proto)
	Connect the CoAP TCP client to a server.
int	coap_client_tcp_close (struct coap_client_tcp *client)
	Close the CoAP TCP client connection.
int	coap_client_tcp_req (struct coap_client_tcp client, struct coap_client_tcp_request req)
	Send CoAP request over TCP.
int	coap_client_tcp_csm_req (struct coap_client_tcp client, uint32_t max_block_size, coap_client_tcp_response_cb_t cb, void user_data)
	Send CSM (Capabilities and Settings Message) over TCP.
void	coap_client_tcp_cancel_requests (struct coap_client_tcp *client)
	Cancel all current TCP requests.
void	coap_client_tcp_cancel_and_reset_all (struct coap_client_tcp *client)
	Cancel and fully reset all requests when changing socket.
struct coap_client_tcp_option	coap_client_tcp_option_initial_block2 (struct coap_client_tcp *client)
	Get initial Block2 option for TCP (BERT-aware).
bool	coap_client_tcp_has_ongoing_exchange (struct coap_client_tcp *client)
	Check if TCP client has ongoing exchange.
int	coap_client_tcp_ping (struct coap_client_tcp *client)
	Send a Ping signal to the server (RFC 8323).
int	coap_client_tcp_release (struct coap_client_tcp client, const char alt_addr, uint32_t hold_off_sec)
	Send a Release signal to the server (RFC 8323).
void	coap_client_tcp_set_event_cb (struct coap_client_tcp client, coap_client_tcp_event_cb_t cb, void user_data)
	Set callback for signaling events (Release/Abort).

Detailed Description

CoAP TCP client API.

Macro Definition Documentation

◆ MAX_COAP_TCP_MSG_LEN

#define MAX_COAP_TCP_MSG_LEN

#include <zephyr/net/coap_client_tcp.h>

Value:

(CONFIG_COAP_CLIENT_MESSAGE_HEADER_SIZE + \

CONFIG_COAP_CLIENT_MESSAGE_SIZE)

Maximum size of a CoAP TCP message.

Typedef Documentation

◆ coap_client_tcp_event_cb_t

typedef void(* coap_client_tcp_event_cb_t) (struct coap_client_tcp *client, enum coap_client_tcp_event event, const union coap_client_tcp_event_data *data, void *user_data)

#include <zephyr/net/coap_client_tcp.h>

Callback for CoAP TCP signaling events (Release/Abort).

Parameters

client	The client instance that received the event.
event	The signaling event type.
data	Event-specific data (may be NULL for some events).
user_data	User provided context.

◆ coap_client_tcp_payload_cb_t

typedef int(* coap_client_tcp_payload_cb_t) (size_t offset, const uint8_t **payload, size_t *len, bool *last_block, void *user_data)

#include <zephyr/net/coap_client_tcp.h>

Callback for providing a payload for the CoAP TCP request.

Parameters

offset	Payload offset from the beginning of a blockwise transfer.
payload	A pointer for the buffer containing the payload block.
len	Requested (maximum) block size on input. The actual payload length on output.
last_block	A pointer to the flag indicating whether more payload blocks are expected.
user_data	User provided context.

Returns: Zero on success, a negative error code to abort upload.

◆ coap_client_tcp_response_cb_t

typedef void(* coap_client_tcp_response_cb_t) (const struct coap_client_response_data *data, void *user_data)

#include <zephyr/net/coap_client_tcp.h>

Callback for CoAP TCP request.

Parameters

data	The CoAP response data.
user_data	User provided context.

◆ coap_client_tcp_socket_config_cb_t

typedef int(* coap_client_tcp_socket_config_cb_t) (int fd, void *user_data)

#include <zephyr/net/coap_client_tcp.h>

Callback to configure the socket before connecting.

Called after socket creation but before connect, allowing the application to set socket options (e.g. TLS credentials).

Parameters

fd	The socket file descriptor.
user_data	User provided context.

Returns: 0 on success, negative error code otherwise.

Enumeration Type Documentation

◆ coap_client_tcp_event

enum coap_client_tcp_event

#include <zephyr/net/coap_client_tcp.h>

CoAP TCP client event types for signaling.

Enumerator
COAP_CLIENT_TCP_EVENT_CSM_UPDATED	CSM capabilities have been updated from server.
COAP_CLIENT_TCP_EVENT_PONG_RECEIVED	Pong received in response to Ping.
COAP_CLIENT_TCP_EVENT_RELEASE	Server initiated connection release (RFC 8323).
COAP_CLIENT_TCP_EVENT_ABORT	Server aborted connection (RFC 8323).

Function Documentation

◆ coap_client_tcp_cancel_and_reset_all()

void coap_client_tcp_cancel_and_reset_all ( struct coap_client_tcp * client )

#include <zephyr/net/coap_client_tcp.h>

Cancel and fully reset all requests when changing socket.

Use when tearing down a transport to ensure clean state for a new socket.

Parameters

client Client instance.

◆ coap_client_tcp_cancel_requests()

void coap_client_tcp_cancel_requests ( struct coap_client_tcp * client )

#include <zephyr/net/coap_client_tcp.h>

Cancel all current TCP requests.

Parameters

client Client instance.

◆ coap_client_tcp_close()

int coap_client_tcp_close ( struct coap_client_tcp * client )

#include <zephyr/net/coap_client_tcp.h>

Close the CoAP TCP client connection.

Cancels any ongoing requests and closes the underlying socket. For graceful shutdown, send a Release signal with coap_client_tcp_release before calling this.

Parameters

client Client instance.

Returns: 0 on success, negative error code otherwise.

◆ coap_client_tcp_connect()

int coap_client_tcp_connect	(	struct coap_client_tcp *	client,
		const struct net_sockaddr *	addr,
		net_socklen_t	addrlen,
		int	proto )

#include <zephyr/net/coap_client_tcp.h>

Connect the CoAP TCP client to a server.

Unlike the UDP client, the TCP client manages the socket internally. This function creates a TCP socket, connects to the server, and automatically sends a CSM (Capabilities and Settings Message) to negotiate capabilities per RFC 8323.

Parameters

client	Client instance.
addr	Destination address of the server.
addrlen	Length of the address structure.
proto	Protocol to use (IPPROTO_TCP or IPPROTO_TLS_1_2).

Returns: 0 on success, negative error code otherwise.

◆ coap_client_tcp_csm_req()

int coap_client_tcp_csm_req	(	struct coap_client_tcp *	client,
		uint32_t	max_block_size,
		coap_client_tcp_response_cb_t	cb,
		void *	user_data )

#include <zephyr/net/coap_client_tcp.h>

Send CSM (Capabilities and Settings Message) over TCP.

Per RFC 8323, CSM should be exchanged when a CoAP-over-TCP connection is established. This negotiates capabilities like max message size and BERT.

Parameters

client	Client instance (must be connected via coap_client_tcp_connect).
max_block_size	Maximum block size to advertise.
cb	Response callback (can be NULL since server may not respond).
user_data	User data for callback.

Returns: 0 on success, -ENOTCONN if not connected, negative error code otherwise.

◆ coap_client_tcp_has_ongoing_exchange()

bool coap_client_tcp_has_ongoing_exchange ( struct coap_client_tcp * client )

#include <zephyr/net/coap_client_tcp.h>

Check if TCP client has ongoing exchange.

Parameters

client Pointer to the CoAP TCP client instance.

Returns: true if there is an ongoing exchange, false otherwise.

◆ coap_client_tcp_init()

int coap_client_tcp_init	(	struct coap_client_tcp *	client,
		const char *	info )

#include <zephyr/net/coap_client_tcp.h>

Initialize the TCP CoAP client.

Parameters

[in]	client	Client instance.
[in]	info	Name for the receiving thread (NULL for default).

Returns: 0 on success, negative error code otherwise.

◆ coap_client_tcp_option_initial_block2()

struct coap_client_tcp_option coap_client_tcp_option_initial_block2 ( struct coap_client_tcp * client )

#include <zephyr/net/coap_client_tcp.h>

Get initial Block2 option for TCP (BERT-aware).

Parameters

client Client instance.

Returns: CoAP client initial Block2 option structure.

◆ coap_client_tcp_ping()

int coap_client_tcp_ping ( struct coap_client_tcp * client )

#include <zephyr/net/coap_client_tcp.h>

Send a Ping signal to the server (RFC 8323).

This sends a Ping signal and waits for Pong response. Can be used for connection keep-alive or RTT measurement.

Parameters

client Client instance (must be connected).

Returns: 0 on success, negative error code otherwise.

◆ coap_client_tcp_release()

int coap_client_tcp_release	(	struct coap_client_tcp *	client,
		const char *	alt_addr,
		uint32_t	hold_off_sec )

#include <zephyr/net/coap_client_tcp.h>

Send a Release signal to the server (RFC 8323).

This signals graceful connection termination. The server should complete pending requests before closing.

Parameters

client	Client instance (must be connected).
alt_addr	Alternative address suggestion (NULL if none).
hold_off_sec	Hold-off time in seconds (0 if none).

Returns: 0 on success, negative error code otherwise.

◆ coap_client_tcp_req()

int coap_client_tcp_req	(	struct coap_client_tcp *	client,
		struct coap_client_tcp_request *	req )

#include <zephyr/net/coap_client_tcp.h>

Send CoAP request over TCP.

Parameters

client	Client instance (must be connected via coap_client_tcp_connect).
req	CoAP request structure.

Returns: 0 on success, -ENOTCONN if not connected, negative error code otherwise.

◆ coap_client_tcp_set_event_cb()

void coap_client_tcp_set_event_cb	(	struct coap_client_tcp *	client,
		coap_client_tcp_event_cb_t	cb,
		void *	user_data )

#include <zephyr/net/coap_client_tcp.h>

Set callback for signaling events (Release/Abort).

Parameters

client	Client instance.
cb	Callback function to invoke on events.
user_data	User data passed to callback.

Data Structures

Macros

Typedefs

Enumerations

Functions

Detailed Description

Macro Definition Documentation

◆ MAX_COAP_TCP_MSG_LEN

Typedef Documentation

◆ coap_client_tcp_event_cb_t

◆ coap_client_tcp_payload_cb_t

◆ coap_client_tcp_response_cb_t

◆ coap_client_tcp_socket_config_cb_t

Enumeration Type Documentation

◆ coap_client_tcp_event

Function Documentation

◆ coap_client_tcp_cancel_and_reset_all()

◆ coap_client_tcp_cancel_requests()

◆ coap_client_tcp_close()

◆ coap_client_tcp_connect()

◆ coap_client_tcp_csm_req()

◆ coap_client_tcp_has_ongoing_exchange()

◆ coap_client_tcp_init()

◆ coap_client_tcp_option_initial_block2()

◆ coap_client_tcp_ping()

◆ coap_client_tcp_release()

◆ coap_client_tcp_req()

◆ coap_client_tcp_set_event_cb()