Lwip中的DHCP服务问题请教

发布于 2016-05-23 10:38:55 浏览：3455 订阅该版

版本RT-Thread 1.2.1，未修改任何内容，神舟IV开发板
定义#define RT_LWIP_DHCP
开启DHCP现象如下
```  | /
- RT -     Thread Operating System
 / |      1.2.1 build May 20 2016
 2006 - 2013 Copyright by rt-thread team
To initialize device:sd0 failed. The error code is 2
File System initialzation failed!
lwIP-1.4.1 initialized!
TCP/IP initialized!
finsh>>                                                              
->:list_if()                                                             
            list_if()                                             
network interface: e0 (Default)                                   
MTU: 1500                                                         
MAC: 00 80 e1 34 58 55                                            
FLAGS: DOWN LINK_UP DHCP ETHARP                                   
ip address: 0.0.0.0                                                   
gw address: 0.0.0.0                                                        
net mask  : 0.0.0.0                                                       
dns server #0: 208.67.222.222                                     
dns server #1: 0.0.0.0                                            
        23, 0x00000017  ```

出现上面的情况是不是表示DHCP获取IP地址不成功？
再进行手动设置set_if,如下：
```finsh>>set_if("e0","192.168.1.30","192.168.1.1","255.255.255.0")
        536893640, 0x200058c8
finsh>>list_if()
network interface: e0 (Default)
MTU: 1500
MAC: 00 80 e1 34 32 59 
FLAGS: DOWN LINK_UP DHCP ETHARP
ip address: 192.168.1.30
gw address: 192.168.1.1
net mask  : 255.255.255.0

dns server #0: 208.67.222.222 
dns server #1: 0.0.0.0
        0, 0x00000000
finsh>>```

仍是出现FLAGS: DOWN LINK_UP DHCP ETHARP,求解为何设置不成功？
  
            
屏蔽#define RT_LWIP_DHCP
关闭DHCP后现象如下
```  | /
- RT -     Thread Operating System
 / |      1.2.1 build May 20 2016
 2006 - 2013 Copyright by rt-thread team
To initialize device:sd0 failed. The error code is 2
File System initialzation failed!
lwIP-1.4.1 initialized!
TCP/IP initialized!
finsh>>                                                           
->:list_if()                                                      
            list_if()                                             
network interface: e0 (Default)                                   
MTU: 1500                                                            
MAC: 00 80 e1 34 58 55                                            
FLAGS: UP LINK_UP ETHARP                                          
ip address: 192.168.1.30                                          
gw address: 192.168.1.1                                           
net mask  : 255.255.255.0                                         
dns server #0: 208.67.222.222

dns server #1: 0.0.0.0

23, 0x00000017

finsh>> ```
交换机任意端口接路由器（路由器开启DHCP服务）
开启RT-Thread 1.2.1中DHCP
```network interface: e0 (Default)                                   
MTU: 1500                                                         
MAC: 00 80 e1 34 58 55                                            
FLAGS: UP LINK_UP DHCP ETHARP                                     
ip address: 192.168.1.100                                         
gw address: 192.168.1.1                                               
net mask  : 255.255.255.0                                         
dns server #0: 192.168.1.1                                               
dns server #1: 0.0.0.0                                            
        23, 0x00000017                                            
              
finsh>>```
请教一下，是不是开启DHCP接入交换机状态应该是up，ip网关等为空 还是

上面显示的down
或者是开启DHCP后接入网络自动获取失败后转为分配一默认地址