applications: serial_lte_modem: sockopt SO_IPV6_DELAYED_ADDR_REFRESH

Add new socket option SO_IPV6_DELAYED_ADDR_REFRESH for delaying
IPv6 address refresh when using IPv6.

Signed-off-by: Andreas Moltumyr <[email protected]>

Author: anhmolt

applications/serial_lte_modem/doc/SOCKET_AT_commands.rst

@@ -571,6 +571,10 @@ Syntax
         Indicates that the socket is in active use by a server application.
         This lets the modem stay in connected mode longer.
 
+  * ``62`` - :c:macro:`SO_IPV6_DELAYED_ADDR_REFRESH`.
+
+    * ``<value>`` is an integer that indicates whether delayed IPv6 address refresh is enabled.
+      It is ``0`` for disabled or ``1`` for enabled.
 
 See :ref:`nRF socket options <nrfxlib:nrf_sockets>` for explanation of the supported options.
 

applications/serial_lte_modem/src/slm_at_socket.c

@@ -346,6 +346,9 @@ static int at_sockopt_to_sockopt(enum at_sockopt at_option, int *level, int *opt
 		*level = IPPROTO_IPV6;
 		*option = SO_IPV6_ECHO_REPLY;
 		break;
+	case AT_SO_IPV6_DELAYED_ADDR_REFRESH:
+		*level = IPPROTO_IPV6;
+		*option = SO_IPV6_DELAYED_ADDR_REFRESH;
 	case AT_SO_BINDTOPDN:
 		*level = SOL_SOCKET;
 		*option = SO_BINDTOPDN;

applications/serial_lte_modem/src/slm_sockopt.h

@@ -26,6 +26,7 @@ enum at_sockopt {
 	AT_SO_BINDTOPDN = 40,
 	AT_SO_TCP_SRV_SESSTIMEO = 55,
 	AT_SO_RAI = 61,
+	AT_SO_IPV6_DELAYED_ADDR_REFRESH = 62,
 };
 
 /**

doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst

@@ -314,6 +314,7 @@ Serial LTE modem
   * DTLS support for the ``#XUDPSVR`` and ``#XSSOCKET`` (UDP server sockets) AT commands when the :file:`overlay-native_tls.conf` configuration file is used.
   * The :kconfig:option:`CONFIG_SLM_PPP_FALLBACK_MTU` Kconfig option that is used to control the MTU used by PPP when the cellular link MTU is not returned by the modem in response to the ``AT+CGCONTRDP=0`` AT command.
   * Handler for new nRF Cloud event type ``NRF_CLOUD_EVT_RX_DATA_DISCON``.
+  * Support for socket option ``AT_SO_IPV6_DELAYED_ADDR_REFRESH``.
 
 * Removed: