Supported functions and socket options

The networking sockets support a list of functions and socket options. The implementation of networking sockets is namespaced (nrf_) to avoid conflicts with functions that might be part of libc or other POSIX compatibility libraries.

Supported functions

Following is a list of supported functions:

• nrf_socket()

• nrf_close()

• nrf_connect()

• nrf_bind()

• nrf_listen()

• nrf_accept()

• nrf_send()

• nrf_sendto()

• nrf_recv()

• nrf_recvfrom()

• nrf_setsockopt()

• nrf_getsockopt()

• nrf_poll()

• nrf_getaddrinfo()

• nrf_freeaddrinfo()

• nrf_fcntl()

• nrf_getifaddrs()

• nrf_freeifaddrs()

• nrf_inet_pton()

• nrf_inet_ntop()

• nrf_setdnsaddr()

• nrf_socket_data_enabled_set()

• nrf_socket_data_enabled_get()

The library supports up to eight networking sockets.

Socket options

The following table shows all socket options supported by the Modem library.

Option level	Option	Type	Operations	Description
NRF_SOL_SOCKET	NRF_SO_ERROR	int	get	Request and clear pending error information on the socket.
NRF_SOL_SOCKET	NRF_SO_REUSEADDR	int	set	Enable reuse of server addresses.
NRF_SOL_SOCKET	NRF_SO_RCVTIMEO	struct nrf_timeval	get/set	Timeout value for a socket receive and accept operations.
NRF_SOL_SOCKET	NRF_SO_SNDTIMEO	struct nrf_timeval	get/set	Timeout value for a socket send operation.
NRF_SOL_SOCKET	NRF_SO_BINDTOPDN	int	set	Bind a socket to a Packet Data Network (PDN) ID.
NRF_SOL_SOCKET	NRF_SO_POLLCB	struct nrf_pollcb	set	Set a callback for nrf_poll() events on sockets.
NRF_SOL_SOCKET	NRF_SO_EXCEPTIONAL_DATA	int	get/set	Send data on a socket as part of an exceptional event.
NRF_SOL_SOCKET	NRF_SO_KEEPOPEN	int	get/set	Keep the socket open when its PDN connection is lost, or the device is set to flight mode.
NRF_SOL_SOCKET	NRF_SO_RAI	int	set	Release Assistance Indication (RAI).
NRF_SOL_SOCKET	NRF_SO_SENDCB	struct nrf_modem_sendcb	set	Callback to be called when a send request is acknowledged.
NRF_IPPROTO_ALL	NRF_SO_SILENCE_ALL	int	get/set	Disable ICMP echo replies on both IPv4 and IPv6.
NRF_IPPROTO_IP	NRF_SO_IP_ECHO_REPLY	int	get/set	Enable ICMP echo replies on IPv4.
NRF_IPPROTO_IPV6	NRF_SO_IPV6_ECHO_REPLY	int	get/set	Enable ICMP echo replies on IPv6.
NRF_IPPROTO_IPV6	NRF_SO_IPV6_DELAYED_ADDR_REFRESH	int	get/set	Delay IPv6 address refresh during power saving mode.
NRF_IPPROTO_TCP	NRF_SO_TCP_SRV_SESSTIMEO	int	get/set	Configure the TCP server session inactivity timeout for a socket.
NRF_SOL_SECURE	NRF_SO_SEC_TAG_LIST	nrf_sec_tag_t *	get/set	Select an array of security tags to use for credentials when connecting.
NRF_SOL_SECURE	NRF_SO_SEC_HOSTNAME	char *	get/set	Configure the hostname used for peer verification.
NRF_SOL_SECURE	NRF_SO_SEC_CIPHERSUITE_LIST	int *	get/set	Select which cipher suites are allowed to be used during the TLS handshake.
NRF_SOL_SECURE	NRF_SO_SEC_PEER_VERIFY	int	get/set	Configure peer verification level.
NRF_SOL_SECURE	NRF_SO_SEC_ROLE	int	get/set	Configure the role for the connection.
NRF_SOL_SECURE	NRF_SO_SEC_SESSION_CACHE	int	get/set	Enable/disable TLS session caching.
NRF_SOL_SECURE	NRF_SO_SEC_SESSION_CACHE_PURGE	int	set	Purge TLS session cache.
NRF_SOL_SECURE	NRF_SO_SEC_DTLS_HANDSHAKE_TIMEO	int	get/set	Configure the DTLS handshake timeout value.
NRF_SOL_SECURE	NRF_SO_SEC_HANDSHAKE_STATUS	int	get	Get the end status of the last completed TLS/DTLS handshake procedure.
NRF_SOL_SECURE	NRF_SO_SEC_DTLS_CID	int	get/set	Enable/disable the DTLS connection ID.
NRF_SOL_SECURE	NRF_SO_SEC_DTLS_CID_STATUS	int	get	Get status of DTLS Connection ID.
NRF_SOL_SECURE	NRF_SO_SEC_DTLS_CONN_SAVE	int	set	Save DTLS connection.
NRF_SOL_SECURE	NRF_SO_SEC_DTLS_CONN_LOAD	int	set	Load DTLS connection.
NRF_SOL_SECURE	NRF_SO_SEC_CIPHERSUITE_USED	int	get	Retrieve the cipher suite used during the TLS/DTLS handshake.
NRF_SOL_SECURE	NRF_SO_SEC_DTLS_FRAG_EXT	int	get/set	Enable/disable the DTLS fragmentation extension.

The details for each socket option are described in the API documentation, notably in the Modem library socket options API and Modem library socket TLS API sections.

Supported flags for socket functions

The following flags are supported for socket functions such as nrf_send(), nrf_recv(), nrf_sendto(), and nrf_recvfrom():

The following table summarizes which send/recv flags are supported by each socket API function.

Flag	nrf_send()	nrf_sendto()	nrf_recv()	nrf_recvfrom()
NRF_MSG_PEEK	Not supported	Not supported	Supported	Supported
NRF_MSG_DONTWAIT	Supported	Supported	Supported	Supported
NRF_MSG_WAITALL	Not supported	Not supported	Supported [1]	Supported [1]
NRF_MSG_WAITACK	Supported [2]	Supported [2]	Not supported	Not supported

[1] (1,2)

Not valid for datagram sockets. The call blocks until the requested number of bytes has been received, an error occurs, or the connection is closed.

[2] (1,2)

The operation blocks until data is acknowledged by the peer (NRF_SOCK_STREAM) or sent on-air by the modem (NRF_SOCK_DGRAM). The behavior is affected by the NRF_SO_SNDTIMEO socket option. This flag cannot be used together with the NRF_SO_SENDCB socket option.

The flags are further described in the API documentation, notably in the Modem library socket flags API section.