Merge pull request #471 from hduffddybz/master

The problem of finding ethernet interface

Author: BernardXiong

components/net/lwip_dhcpd/dhcp_server.c

@@ -376,13 +376,24 @@ static void dhcpd_thread_entry(void *parameter)
 void dhcpd_start(char* netif_name)
 {
     rt_thread_t thread;
-    struct netif *netif = RT_NULL;
+    struct netif *netif = netif_list;
 
-    /* find ethernet interface. */
-    netif = netif_find(netif_name);
-    if (netif == RT_NULL)
+    if(strlen(netif_name) > sizeof(netif->name))
+    {
+        rt_kprintf("network interface name too long!\r\n");
+        return;
+    }
+    while(netif != RT_NULL)
     {
-        DEBUG_PRINTF("Not found network interface:%s\n", netif_name);
+        if(strncmp(netif_name, netif->name, sizeof(netif->name)) == 0)
+            break;
+
+        netif = netif->next;
+        if( netif == RT_NULL )
+        {
+            rt_kprintf("network interface: %s not found!\r\n", netif_name);
+            return;
+        }
     }
 
     thread = rt_thread_create("dhcpd",