sample: net: mqtt: add ALPN Sample code for aws

due to MQTT now have ALPN support
the example code of using ALPN to connect MQTT
over port 443 need to be added

Signed-off-by: sukrit buddeewong <sukrit.omu@gmail.com>

samples/net/cloud/aws_iot_mqtt/Kconfig

@@ -14,6 +14,12 @@ config AWS_ENDPOINT
 	  Endpoint (hostname) of the AWS MQTT broker.
 	  Note that the endpoint is different when using AWS Device Advisor.
 
+config AWS_MQTT_PORT
+	int "MQTT Port"
+	default 8883
+	help
+	  Set port of AWS MQTT broker.
+
 config AWS_THING_NAME
 	string "AWS Thing name"
 	default "myThingName"

samples/net/cloud/aws_iot_mqtt/README.rst

@@ -45,6 +45,7 @@ Core region, thing, and device advisor configuration:
 
 - :kconfig:option:`CONFIG_AWS_ENDPOINT`: The AWS IoT Core broker endpoint, found in the AWS IoT Core
   console. This will be specific if running a test suite using device advisor.
+- :kconfig:option:`CONFIG_AWS_MQTT_PORT`: Port number for AWS IoT Core MQTT broker.
 - :kconfig:option:`CONFIG_AWS_THING_NAME`: The name of the thing created in AWS IoT Core. Associated
   with the certificate it will be used as the client id. We will use
   ``zephyr_sample`` in this example.

samples/net/cloud/aws_iot_mqtt/prj.conf

@@ -1,4 +1,5 @@
 CONFIG_AWS_ENDPOINT="a31gokdeokxhl8-ats.iot.eu-west-1.amazonaws.com"
+CONFIG_AWS_MQTT_PORT=8883
 CONFIG_AWS_THING_NAME="zephyr_sample"
 CONFIG_AWS_PUBLISH_TOPIC="zephyr_sample/data"
 CONFIG_AWS_SUBSCRIBE_TOPIC="zephyr_sample/downlink"
@@ -45,6 +46,7 @@ CONFIG_NET_BUF_TX_COUNT=32
 CONFIG_MQTT_LIB=y
 CONFIG_MQTT_LIB_TLS=y
 CONFIG_MQTT_KEEPALIVE=60
+CONFIG_MQTT_LIB_TLS_USE_ALPN=y
 
 # TLS
 CONFIG_MBEDTLS=y
@@ -58,3 +60,4 @@ CONFIG_MBEDTLS_AES_ROM_TABLES=y
 CONFIG_MBEDTLS_TLS_VERSION_1_2=y
 CONFIG_MBEDTLS_MEMORY_DEBUG=y
 CONFIG_MBEDTLS_HAVE_TIME_DATE=y
+CONFIG_MBEDTLS_SSL_ALPN=y

samples/net/cloud/aws_iot_mqtt/src/dhcp.c

@@ -35,7 +35,7 @@ static void handler(struct net_mgmt_event_callback *cb,
 	}
 
 	for (i = 0; i < NET_IF_MAX_IPV4_ADDR; i++) {
-		if (iface->config.ip.ipv4->unicast[i].addr_type !=
+		if (iface->config.ip.ipv4->unicast[i].ipv4.addr_type !=
 		    NET_ADDR_DHCP) {
 			continue;
 		}

samples/net/cloud/aws_iot_mqtt/src/main.c

@@ -30,7 +30,7 @@ LOG_MODULE_REGISTER(aws, LOG_LEVEL_DBG);
 
 #define SNTP_SERVER "0.pool.ntp.org"
 
-#define AWS_BROKER_PORT "8883"
+#define AWS_BROKER_PORT CONFIG_AWS_MQTT_PORT
 
 #define MQTT_BUFFER_SIZE 256u
 #define APP_BUFFER_SIZE	 4096u
@@ -54,6 +54,10 @@ static uint32_t messages_received_counter;
 static bool do_publish;	  /* Trigger client to publish */
 static bool do_subscribe; /* Trigger client to subscribe */
 
+#if (CONFIG_AWS_MQTT_PORT == 443 && !defined(CONFIG_MQTT_LIB_WEBSOCKET))
+static const char * const alpn_list[] = {"x-amzn-mqtt-ca"};
+#endif
+
 #define TLS_TAG_DEVICE_CERTIFICATE 1
 #define TLS_TAG_DEVICE_PRIVATE_KEY 1
 #define TLS_TAG_AWS_CA_CERTIFICATE 2
@@ -266,6 +270,10 @@ static void aws_client_setup(void)
 	tls_config->sec_tag_count = ARRAY_SIZE(sec_tls_tags);
 	tls_config->hostname = CONFIG_AWS_ENDPOINT;
 	tls_config->cert_nocopy = TLS_CERT_NOCOPY_NONE;
+#if (CONFIG_AWS_MQTT_PORT == 443 && !defined(CONFIG_MQTT_LIB_WEBSOCKET))
+	tls_config->alpn_protocol_name_list = alpn_list;
+	tls_config->alpn_protocol_name_count = ARRAY_SIZE(alpn_list);
+#endif
 }
 
 struct backoff_context {
@@ -443,8 +451,10 @@ static int resolve_broker_addr(struct sockaddr_in *broker)
 		.ai_socktype = SOCK_STREAM,
 		.ai_protocol = 0,
 	};
+	char port_string[6] = {0};
 
-	ret = zsock_getaddrinfo(CONFIG_AWS_ENDPOINT, AWS_BROKER_PORT, &hints, &ai);
+	sprintf(port_string, "%d", AWS_BROKER_PORT);
+	ret = zsock_getaddrinfo(CONFIG_AWS_ENDPOINT, port_string, &hints, &ai);
 	if (ret == 0) {
 		char addr_str[INET_ADDRSTRLEN];