Man page - coap_new_context(3)

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Manual

COAP_CONTEXT

NAME
SYNOPSIS
DESCRIPTION
FUNCTIONS
RETURN VALUES
SEE ALSO
FURTHER INFORMATION
BUGS
AUTHORS

NAME

coap_context, coap_new_context, coap_free_context, coap_context_set_max_idle_sessions, coap_context_get_max_idle_sessions, coap_context_set_max_handshake_sessions, coap_context_get_max_handshake_sessions, coap_context_set_session_timeout, coap_context_get_session_timeout, coap_context_set_csm_timeout, coap_context_get_csm_timeout, coap_context_set_max_token_size - Work with CoAP contexts

SYNOPSIS

#include <coap3/coap.h>

coap_context_t *coap_new_context(const coap_address_t * listen_addr );

void coap_free_context(coap_context_t * context );

void coap_context_set_max_idle_sessions(coap_context_t * context , unsigned int max_idle_sessions );

unsigned int coap_context_get_max_idle_sessions( const coap_context_t * context );

void coap_context_set_max_handshake_sessions(coap_context_t * context , unsigned int max_handshake_sessions );

unsigned int coap_context_get_max_handshake_sessions( const coap_context_t * context );

void coap_context_set_session_timeout(coap_context_t * context , unsigned int session_timeout );

unsigned int coap_context_get_session_timeout( const coap_context_t * context );

void coap_context_set_csm_timeout(coap_context_t * context , unsigned int csm_timeout );

unsigned int coap_context_get_csm_timeout(const coap_context_t * context );

void coap_context_set_max_token_size(coap_context_t * context , size_t max_token_size );

For specific (D)TLS library support, link with -lcoap-3-notls , -lcoap-3-gnutls , -lcoap-3-openssl , -lcoap-3-mbedtls or -lcoap-3-tinydtls . Otherwise, link with -lcoap-3 to get the default (D)TLS library support.

DESCRIPTION

This man page focuses on the CoAP Context and how to update or get information from the opaque coap_context_t structure.

The CoAP stack’s global state is stored in a coap_context_t Context object. Resources, Endpoints and Sessions are associated with this context object. There can be more than one coap_context_t object per application, it is up to the application to manage each one accordingly.

FUNCTIONS

Function: coap_new_context()

The coap_new_context () function creates a new Context that is then used to keep all the CoAP Resources, Endpoints and Sessions information. The optional listen_addr parameter, if set for a CoAP server, creates an Endpoint that is added to the context that is listening for un-encrypted traffic on the IP address and port number defined by listen_addr .

Function: coap_free_context()

The coap_free_context () function must be used to release the CoAP stack context . It clears all entries from the receive queue and send queue and deletes the Resources that have been registered with context , and frees the attached Sessions and Endpoints.

WARNING: It is unsafe to call coap_free_context () in an atexit() handler as other libraries may also call atexit() and clear down some CoAP required functionality.

Function: coap_context_set_max_idle_sessions()

The coap_context_set_max_idle_sessions () function sets the maximum number of idle server sessions to max_idle_sessions for context . If this number is exceeded, the least recently used server session is completely removed. 0 (the initial default) means that the number of idle sessions is not monitored.

Function: coap_context_get_max_idle_sessions()

The coap_context_get_max_idle_sessions () function returns the maximum number of idle server sessions for context .

Function: coap_context_set_max_handshake_sessions()

The coap_context_set_max_handshake_sessions () function sets the maximum number of outstanding server sessions in (D)TLS handshake to max_handshake_sessions for context . If this number is exceeded, the least recently used server session in handshake is completely removed. 0 (the default) means that the number of handshakes is not monitored.

Function: coap_context_get_max_handshake_sessions()

The coap_context_get_max_handshake_sessions () function returns the maximum number of outstanding server sessions in (D)TLS handshake for context .

Function: coap_context_set_session_timeout()

The coap_context_set_session_timeout () function sets the number of seconds of inactivity to session_timeout for context before an idle server session is removed. 0 (the default) means wait for the default of 300 seconds.

Function: coap_context_get_session_timeout()

The coap_context_get_session_timeout () function returns the seconds to wait before timing out an idle server session for context .

Function: coap_context_set_csm_timeout()

The coap_context_set_csm_timeout () function sets the number of seconds to wait for a (TCP) CSM negotiation response from the peer to csm_timeout for context . 0 (the default) means wait forever.

Function: coap_context_get_csm_timeout()

The coap_context_get_csm_timeout () function returns the seconds to wait for a (TCP) CSM negotiation response from the peer for context ,

Function: coap_context_set_max_token_size()

The coap_context_set_max_token_size () function sets the max_token_size for context . max_token_size must be greater than 8 to indicate support for RFC8974 up to max_token_size bytes, else 8 to disable RFC8974 (if previously set).

NOTE: For the client, it will send an initial PDU to test the server supports the requested extended token size as per "RFC8794 Section 2.2.2"

RETURN VALUES

coap_new_context () returns a newly created context or NULL if there is a creation failure.

coap_context_get_max_idle_sessions () returns the maximum number of idle server sessions.

coap_context_get_max_handshake_sessions () returns the maximum number of outstanding server sessions in (D)TLS handshake.

coap_context_get_session_timeout () returns the seconds to wait before timing out an idle server session.

coap_context_get_csm_timeout () returns the seconds to wait for a (TCP) CSM negotiation response from the peer.

SEE ALSO

coap_session (3)

FURTHER INFORMATION

See

"RFC7252: The Constrained Application Protocol (CoAP)"

"RFC8974: Extended Tokens and Stateless Clients in the Constrained Application Protocol (CoAP)"

for further information.

BUGS

Please report bugs on the mailing list for libcoap: libcoap-developers@lists.sourceforge.net or raise an issue on GitHub at https://github.com/obgm/libcoap/issues

AUTHORS

The libcoap project <libcoap-developers@lists.sourceforge.net>