samples/net/mqtt: Reduce tx/rx buffer size and update mqtt_publish_read

Set CONFIG_IP_BUF_RX_SIZE and CONFIG_IP_BUF_TX_SIZE to 4.
Modify mqtt_publish_read to retrieve topic name and message as strings.
Change printf for printk.

Change-Id: I6746846cb3359096d87dfbb3134d6a3a95bf087e
Signed-off-by: Flavio Santes <flavio.santes@intel.com>

samples/net/paho_mqtt_client/prj_ethernet.conf

@@ -1,4 +1,5 @@
-CONFIG_STDOUT_CONSOLE=y
+CONFIG_PRINTK=y
+
 CONFIG_NETWORKING=y
 CONFIG_ETHERNET=y
 CONFIG_ETH_DW=y
@@ -7,7 +8,8 @@ CONFIG_NANO_TIMEOUTS=y
 CONFIG_NETWORKING_WITH_TCP=y
 CONFIG_NETWORKING_WITH_IPV4=y
 CONFIG_NETWORKING_IPV6_NO_ND=y
-CONFIG_IP_BUF_RX_SIZE=12
+
-CONFIG_IP_BUF_TX_SIZE=13
+CONFIG_IP_BUF_RX_SIZE=4
+CONFIG_IP_BUF_TX_SIZE=4
 
 #CONFIG_NETWORKING_WITH_LOGGING=y

samples/net/paho_mqtt_client/src/main.c

@@ -15,9 +15,7 @@
  */
 
 #include <zephyr.h>
-#include <stdio.h>
+#include <misc/printk.h>
-#include <sections.h>
-#include <errno.h>
 
 #include "config.h"
 #include "tcp.h"
@@ -30,17 +28,21 @@ uint8_t stack[STACK_SIZE];
 
 struct net_context *ctx;
 
-
 void fiber(void)
 {
 	char *client_name = "zephyr_client";
 	char *topic = "zephyr";
 	char *msg = "Hello World from Zephyr!";
+	/* it is assumed that these buffers have enough space to
+	 * store the incoming topic and msg!
+	 */
+	char received_topic[32];
+	char received_msg[64];
 	int rc;
 
 	do {
 		rc = mqtt_connect(ctx, client_name);
-		printf("Connect: %s\n", RC_MSG(rc));
+		printk("Connect: %s\n", RC_MSG(rc));
 
 		fiber_sleep(APP_SLEEP_TICKS);
 	} while (rc != 0);
@@ -48,20 +50,24 @@ void fiber(void)
 	do {
 
 		rc = mqtt_subscribe(ctx, topic);
-		printf("Subscribe: %s\n", RC_MSG(rc));
+		printk("Subscribe: %s\n", RC_MSG(rc));
 
 		fiber_sleep(APP_SLEEP_TICKS);
 	} while (rc != 0);
 
 	do {
 		rc = mqtt_pingreq(ctx);
-		printf("Pingreq: %s\n", RC_MSG(rc));
+		printk("Pingreq: %s\n", RC_MSG(rc));
 
 		rc = mqtt_publish(ctx, topic, msg);
-		printf("Publish: %s\n", RC_MSG(rc));
+		printk("Publish: %s\n", RC_MSG(rc));
 
-		rc = mqtt_publish_read(ctx);
+		rc = mqtt_publish_read(ctx, received_topic, received_msg);
-		printf("Publish read: %s\n", RC_MSG(rc));
+		if (rc == 0) {
+			printk("\n\tReceived topic: %s, msg: %s\n",
+			       received_topic, received_msg);
+		}
+		printk("Publish read: %s\n", RC_MSG(rc));
 
 		fiber_sleep(APP_SLEEP_TICKS);
 	} while (1);

samples/net/paho_mqtt_client/src/mqtt.c

@@ -17,6 +17,7 @@
 #include <string.h>
 #include <errno.h>
 
+#include "config.h"
 #include "mqtt.h"
 #include "tcp.h"
 
@@ -149,7 +150,7 @@ int mqtt_pingreq(struct net_context *ctx)
 	return rc == 1 ? 0 : -EINVAL;
 }
 
-int mqtt_publish_read(struct net_context *ctx)
+int mqtt_publish_read(struct net_context *ctx, char *topic_str, char *msg_str)
 {
 	MQTTString topic;
 	unsigned char dup;
@@ -169,15 +170,16 @@ int mqtt_publish_read(struct net_context *ctx)
 	rc = MQTTDeserialize_publish(&dup, &qos, &retained, &msg_id,
 				     &topic, &msg, &msg_len,
 				     mqtt_buffer, rx_len);
-	rc = rc == 1 ? 0 : -EIO;
-	if (rc == 0) {
-		printf("\n\tReceived message: [%.*s] %.*s\n\n",
-		       topic.lenstring.len, topic.lenstring.data,
-		       msg_len, msg);
-	}
-	return rc;
-}
 
+	if (rc == 1) {
+		memcpy(topic_str, topic.lenstring.data, topic.lenstring.len);
+		topic_str[topic.lenstring.len] = '\0';
+		memcpy(msg_str, msg, msg_len);
+		msg_str[msg_len] = '\0';
+		return 0;
+	}
+	return -EINVAL;
+}
 
 int mqtt_subscribe(struct net_context *ctx, char *topic)
 {
@@ -212,4 +214,3 @@ int mqtt_subscribe(struct net_context *ctx, char *topic)
 
 	return rc == 1 ? granted_qos : -EINVAL;
 }
-

samples/net/paho_mqtt_client/src/mqtt.h

@@ -22,7 +22,7 @@
 int mqtt_connect(struct net_context *ctx, char *client_name);
 int mqtt_disconnect(struct net_context *ctx);
 int mqtt_publish(struct net_context *ctx, char *topic, char *msg);
-int mqtt_publish_read(struct net_context *ctx);
+int mqtt_publish_read(struct net_context *ctx, char *topic_str, char *msg_str);
 int mqtt_subscribe(struct net_context *ctx, char *topic);
 int mqtt_pingreq(struct net_context *ctx);
 

samples/net/paho_mqtt_client/src/tcp.c

@@ -14,6 +14,10 @@
  * limitations under the License.
  */
 
+#include <string.h>
+#include <errno.h>
+#include <misc/printk.h>
+
 #include "config.h"
 #include "tcp.h"
 
@@ -21,9 +25,6 @@
 #include <net/net_core.h>
 #include <net/net_socket.h>
 
-#include <errno.h>
-#include <stdio.h>
-
 uip_ipaddr_t uip_hostaddr =	{ { CLIENT_IPADDR0, CLIENT_IPADDR1,
 				    CLIENT_IPADDR2, CLIENT_IPADDR3 } };
 
@@ -38,17 +39,16 @@ uip_ipaddr_t uip_netmask =	{ { NETMASK0, NETMASK1, NETMASK2, NETMASK3 } };
 
 #define INET_FAMILY		AF_INET
 
-
 int tcp_tx(struct net_context *ctx, uint8_t *buf,  size_t size)
 {
-	int rc = 0;
-	uint8_t *ptr;
 	struct net_buf *nbuf = NULL;
+	uint8_t *ptr;
+	int rc = 0;
 
 	nbuf = ip_buf_get_tx(ctx);
 	if (nbuf == NULL) {
-		printf("[%s:%d] Unable to get buffer\n", __func__, __LINE__);
+		printk("[%s:%d] Unable to get buffer\n", __func__, __LINE__);
-		return -1;
+		return -EINVAL;
 	}
 
 	ptr = net_buf_add(nbuf, size);
@@ -63,16 +63,16 @@ int tcp_tx(struct net_context *ctx, uint8_t *buf,  size_t size)
 		}
 		switch (rc) {
 		case -EINPROGRESS:
-			printf("%s: no connection yet, try again\n", __func__);
+			printk("%s: no connection yet, try again\n", __func__);
 			fiber_sleep(TCP_RETRY_TIMEOUT);
 			break;
 		case -EAGAIN:
 		case -ECONNRESET:
-			printf("%s: no connection, try again later\n", __func__);
+			printk("%s: no connection, try again later\n", __func__);
 			fiber_sleep(TCP_RETRY_TIMEOUT);
 			break;
 		default:
-			printf("%s: sending %d bytes failed\n",
+			printk("%s: sending %d bytes failed\n",
 			      __func__, size);
 			ip_buf_unref(nbuf);
 			return -EIO;
@@ -84,8 +84,8 @@ int tcp_tx(struct net_context *ctx, uint8_t *buf,  size_t size)
 
 int tcp_rx(struct net_context *ctx, uint8_t *buf, size_t *read_bytes, size_t size)
 {
-	int rc;
 	struct net_buf *nbuf;
+	int rc;
 
 	nbuf = net_receive(ctx, TCP_RX_TIMEOUT);
 	rc = -EIO;
@@ -119,7 +119,7 @@ int tcp_init(struct net_context **ctx)
 			       &server, SERVER_MQTT_PORT,
 			       &client, CLIENT_MQTT_PORT);
 	if (*ctx == NULL) {
-		printf("%s: Unable to get network context\n", __func__);
+		printk("%s: Unable to get network context\n", __func__);
 		return -EINVAL;
 	}
 	return 0;