samples: net: dsa: Enable DHCPv4 and start it when interface is up

Enable DHCPv4 when network interface goes up. This makes it easier
to test IP connectivity with DSA.

Signed-off-by: Jukka Rissanen <jukka.rissanen@nordicsemi.no>
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>

samples/net/dsa/prj.conf

@@ -2,7 +2,7 @@ CONFIG_NETWORKING=y
 CONFIG_NET_LOG=y
 CONFIG_NET_IPV6=y
 CONFIG_NET_IPV4=y
-CONFIG_NET_DHCPV4=n
+CONFIG_NET_DHCPV4=y
 CONFIG_NET_UDP=y
 CONFIG_NET_TCP=y
 CONFIG_NET_STATISTICS=y
@@ -18,6 +18,9 @@ CONFIG_NET_IF_UNICAST_IPV6_ADDR_COUNT=5
 CONFIG_NET_IF_MCAST_IPV6_ADDR_COUNT=5
 CONFIG_NET_IF_UNICAST_IPV4_ADDR_COUNT=1
 CONFIG_NET_MAX_CONTEXTS=4
+CONFIG_ZVFS_OPEN_MAX=4
+CONFIG_ZVFS_POLL_MAX=4
+CONFIG_NET_MAX_CONN=4
 
 CONFIG_INIT_STACKS=y
 CONFIG_PRINTK=y
@@ -46,3 +49,10 @@ CONFIG_REQUIRES_FULL_LIBC=y
 
 CONFIG_NET_IF_MAX_IPV4_COUNT=4
 CONFIG_NET_IF_MAX_IPV6_COUNT=4
+
+CONFIG_NET_MGMT=y
+CONFIG_NET_MGMT_EVENT=y
+CONFIG_NET_MGMT_EVENT_STACK_SIZE=2048
+
+CONFIG_NET_HOSTNAME_ENABLE=y
+CONFIG_NET_HOSTNAME="dsa"

samples/net/dsa/src/main.c

@@ -39,7 +39,8 @@ static void dsa_iface_find_cb(struct net_if *iface, void *user_data)
 				if (user == NULL) {
 					continue;
 				}
-				LOG_INF("User interface %d found.", i);
+				LOG_INF("[%d] User interface %d found.", i,
+					net_if_get_by_iface(user));
 
 				ifaces->lan[i] = user;
 			}
@@ -48,12 +49,40 @@ static void dsa_iface_find_cb(struct net_if *iface, void *user_data)
 	}
 }
 
+#if defined(CONFIG_NET_MGMT_EVENT)
+#define EVENT_MASK (NET_EVENT_IF_UP)
+static struct net_mgmt_event_callback mgmt_cb;
+
+static void event_handler(struct net_mgmt_event_callback *cb,
+			  uint32_t mgmt_event, struct net_if *iface)
+{
+	ARG_UNUSED(iface);
+	ARG_UNUSED(cb);
+
+	if (mgmt_event == NET_EVENT_IF_UP) {
+		LOG_INF("Port %d is up", net_if_get_by_iface(iface));
+
+#if defined(CONFIG_NET_DHCPV4)
+		net_dhcpv4_start(iface);
+#endif
+
+		return;
+	}
+}
+#endif /* CONFIG_NET_MGMT_EVENT */
+
 int main(void)
 {
 	/* Initialize interfaces - read them to user_data */
 	(void)memset(&user_data, 0, sizeof(user_data));
 	net_if_foreach(dsa_iface_find_cb, &user_data);
 
+#if defined(CONFIG_NET_MGMT_EVENT)
+	net_mgmt_init_event_callback(&mgmt_cb,
+				     event_handler, EVENT_MASK);
+	net_mgmt_add_event_callback(&mgmt_cb);
+#endif /* CONFIG_NET_MGMT_EVENT */
+
 #if defined(CONFIG_NET_SAMPLE_DSA_LLDP)
 	dsa_lldp(&user_data);
 #endif