How to use SNI with DTLS 1.2 on CoAP

[Christian22]

Hello,

I only want to know if it is possible to enable and configure the Server Name Indication (SNI) for DTLS on BSD sockets and CONFIG_NET_SOCKETS_OFFLOAD=y (not using the Zephyr IP stack) in a CoAP communication? 

If yes, how can I configure it?

Which option do I need to set in case I can configure it with the following function call?

setsockopt(m_socket, ?, ?, ?, ?);

I use the following setup:

• nrf9160 DK revision 1.1.0
• ncs v2.0.0
• modem firmware is mfw_nrf9160_1.3.2

Thanks in advance.

Best regards,

Christian

[Achim Kraus]

According CoAP over DTLS 7.2, TLS_HOSTNAME is supported and may do the job.

err = setsockopt(sock, SOL_TLS, TLS_HOSTNAME, CONFIG_COAP_SERVER_HOSTNAME,
	 strlen(CONFIG_COAP_SERVER_HOSTNAME));
if (err) {
	LOG_ERR("Failed to setup TLS hostname (%s), errno %d\n",
		CONFIG_COAP_SERVER_HOSTNAME, errno);
	return -errno;
}

(I haven't tested it on my own.)

[Christian22]

Hi Achim,

Thanks for your help.

It works. I have tested it.