一、简介：
本文会基于沁恒微电子以太网协议栈芯片CH394进行DHCP和DNS示例（主控芯片为CH32V307，SPI接口），简单演示通过UDP模式下进行DHCP报文发送和解析，同时利用DNS进行域名访问。
CH394芯片自带10/100M以太网介质传输层MAC和物理层收发器PHY，完全兼容IEEE802.3协议， 内置了IP、ARP、ICMP、IGMP、UDP、TCP等以太网协议栈固件。单片机系统可以方便的通过CH394芯 片进行网络通讯。CH394支持网络唤醒模式（WOL）和掉电模式。
二、应用：
DHCP过程是通过UDP作为传输协议，设备端通过UDP将消息传输到具有DHCP服务器设备的67号端口，DHCP服务器返回消息给客户端的68号端口。大致流程为设备端发起DHCP DISCOVER报文请求HDCP------DHCP服务器提供OFFER------设备端发送Request报文确认------服务器发起ACK，DHCP成功。具体流程和协议内容可以看此贴DHCP介绍与实现方法 - 小小小学僧 - 博客园。
程序步骤：
1、初始化SPI接口--->复位CH394Q--->检测PHY状态--->初始化CH394--->收发缓存
CH394Q_GPIO_Init();
CH394Q_SPIPort_Init();
Delay_Ms(100);
CH394Q_ResetHW(); // CH394Q硬件复位
printf("\r\n CH394Q EVT Test Demo \r\n");
i = CH394Q_GetCHIPV();
printf(" CH394Q CHIPV : %2x\r\n", i);
CH394Q_PHY_Check(); // PHY连接检测
CH394Q_InfParam(CH394Q_IPAddr, CH394Q_IPMask , CH394Q_GWIPAddr, CH394Q_MACAddr); // 设置CH394Q网络参数
CH394Q_SocketBuf_Init(TX_BUFF, RX_BUFF); // 初始化8个Socket的发送接收缓存大小
2、DHCP运行：封装DHCP DISCOVER报文------创建UDP SOCKET（SOCKET3）发送该报文------接收DHCP服务器offer数据并解析DHCP服务器提供的IP等参数------通过UDP发送DHCP request报文-------接收DHCP服务器的ACK报文，此时表明DHCP成功。其他情况下通过定时器进行计数，当DHCP流程进入某一阶段无法或者相应状态时进超时计数，超时后并重新进行DHCP DIscover报文发送，直到DHCP流程完成。（报文封装和校验附件代码查看）
u8 DHCP_run(void)//0
{
uint8_t type;
uint8_t ret;
if(Conflict_flag == 1)
{
init_dhcp_client(); /*初始化DHCP客户端*/
TIM2_Init(); /*初始化定时器*/
Conflict_flag = 0;
}
if(dhcp_state == STATE_DHCP_STOP)
{
Conflict_flag = 1;
return DHCP_STOPPED;
}
if(CH394Q_GetSn_STA(SOCK_DHCP) != SOCK_UDP)
CH394Socket_Init(3, Sn_MODE_UDP, DHCP_CLIENT_PORT, 0x00);
ret = DHCP_RUNNING;
type = parseDHCPMSG();
switch ( dhcp_state ) {
case STATE_DHCP_READY :
DHCP_allocated_ip[0] = 0;
DHCP_allocated_ip[1] = 0;
DHCP_allocated_ip[2] = 0;
DHCP_allocated_ip[3] = 0;
send_DHCP_DISCOVER();
dhcp_time = 0;
dhcp_state = STATE_DHCP_DISCOVER;
//Delay_Us(1);
break;
case STATE_DHCP_DISCOVER :
if (type == DHCP_OFFER)
{
DHCP_allocated_ip[0] = pDHCPMSG->yiaddr[0];
DHCP_allocated_ip[1] = pDHCPMSG->yiaddr[1];
DHCP_allocated_ip[2] = pDHCPMSG->yiaddr[2];
DHCP_allocated_ip[3] = pDHCPMSG->yiaddr[3];
send_DHCP_REQUEST();
dhcp_time = 0;
dhcp_state = STATE_DHCP_REQUEST;
}
else
ret = check_DHCP_timeout();
break;
case STATE_DHCP_REQUEST :
if (type == DHCP_ACK)
{
if (check_DHCP_leasedIP())
{
// Network info assignment from DHCP
printf(" DHCP 已获取：\r\n");
printf(" I P 地址：%d.%d.%d.%d\r\n",DHCP_allocated_ip[0],DHCP_allocated_ip[1],DHCP_allocated_ip[2],DHCP_allocated_ip[3]);
printf(" 子网掩码：%d.%d.%d.%d\r\n",DHCP_allocated_sn[0],DHCP_allocated_sn[1],DHCP_allocated_sn[2],DHCP_allocated_sn[3]);
printf(" 网关地址：%d.%d.%d.%d\r\n",DHCP_allocated_gw[0],DHCP_allocated_gw[1],DHCP_allocated_gw[2],DHCP_allocated_gw[3]);
dhcp_ip_assign();
reset_DHCP_timeout();
dhcp_state = STATE_DHCP_LEASED;
DHCP_Flag=1;
}
else
{
reset_DHCP_timeout();
dhcp_ip_conflict();
dhcp_state = STATE_DHCP_READY;
}
}
else if (type == DHCP_NAK)
{
printf("> Receive DHCP_NACK\r\n");
reset_DHCP_timeout();
dhcp_state = STATE_DHCP_DISCOVER;
}
else
ret = check_DHCP_timeout();
break;
case STATE_DHCP_LEASED :
ret = DHCP_IP_LEASED;
if ((dhcp_lease_time != DEFAULT_LEASETIME) && ((dhcp_lease_time/2) < dhcp_time)) {
#ifdef _DHCP_DEBUG_
printf("> Maintains the IP address \r\n");
#endif
type = 0;
OLD_allocated_ip[0] = DHCP_allocated_ip[0];
OLD_allocated_ip[1] = DHCP_allocated_ip[1];
OLD_allocated_ip[2] = DHCP_allocated_ip[2];
OLD_allocated_ip[3] = DHCP_allocated_ip[3];
DHCP_XID++;
send_DHCP_REQUEST();
reset_DHCP_timeout();
dhcp_state = STATE_DHCP_REREQUEST;
}
break;
case STATE_DHCP_REREQUEST :
ret = DHCP_IP_LEASED;
if (type == DHCP_ACK) {
dhcp_retry_count = 0;
if (OLD_allocated_ip[0] != DHCP_allocated_ip[0] ||
OLD_allocated_ip[1] != DHCP_allocated_ip[1] ||
OLD_allocated_ip[2] != DHCP_allocated_ip[2] ||
OLD_allocated_ip[3] != DHCP_allocated_ip[3])
{
ret = DHCP_IP_CHANGED;
dhcp_ip_update();
#ifdef _DHCP_DEBUG_
printf(">IP changed.\r\n");
#endif
}
#ifdef _DHCP_DEBUG_
else printf(">IP is continued.\r\n");
#endif
reset_DHCP_timeout();
dhcp_state = STATE_DHCP_LEASED;
}
else if (type == DHCP_NAK)
{
#ifdef _DHCP_DEBUG_
printf("> Receive DHCP_NACK, Failed to maintain ip\r\n");
#endif
reset_DHCP_timeout();
dhcp_state = STATE_DHCP_DISCOVER;
}
else ret = check_DHCP_timeout();
break;
default :
break;
}
return ret;
}
3、DNS域名解析：创建UDP Socket------封装DNS查询报文------通过UDP Socket发送DNS查询报文（注意DNS的目的端口为固定端口：53，MDNS端口为5353）。------DNS服务器回复DNS应答报文------接收报文并解析（具体报文内容参考该贴：DNS介绍与实现方法 - 小小小学僧 - 博客园），
uint8_t DnsQuery(uint8_t s, uint8_t * name, uint8_t * pSip)
{
struct dhdr dhp;
uint16_t len,cnt;
if(status>1)
{
count++;
printf("count = %2d\n",(uint16_t)count);
Delay_Ms(1);
if(count>2000)
{
printf("DNS Fail!!!!\n");
count =0;
status =0;
}
}
if(status == 1)
{
CH394Q_UDPSocketInit(s, Sn_MODE_UDP, 2000);
status = 2;
printf("status = 2!\n");
}
if(status ==2)
{
len = MakeDnsQueryMsg(0,(char *)name, dns_buf, MAX_DNS_BUF_SIZE);
cnt = CH394Q_SocketSendTo(s,dns_buf,len,DNS_SERVER_IP,IPPORT_DOMAIN);
if (cnt == 0) return(0);
else
{
status = 3;
printf("status = 3!\n");
}
}
if(status ==4)
{
return(parseMSG(&dhp, dns_buf, pSip)); /*解析响应报文并返回结果*/
}
return 0;
}
3、主函数运行：
while(1)
{
DHCP_run(); //DHCP运行
if(DHCP_Flag==1)
{
if(Socket_FLag==0)
{ CH394Q_SetGINTE(0XFF); // 使能中断
CH394Q_SetSINTE(0XFF); // 使能socket中断
printf(" TCP SERVER......\r\n");
CH394Q_SetSn_MODE(0, Sn_MODE_NA); //创建TCP SERVER socket
printf("scoket1= %x\r\n", CH394Q_GetSn_MODE(0));
CH394Q_TCPServerSocketInit( 0, Sn_MODE_TCP |Sn_MODE_NA , CH394Q_Port);
printf("scoket= %x\r\n", CH394Q_GetSn_MODE(0));
Socket_FLag=1;
}
if(QueryCH394QInterrupt() == 0)
{
CH394Q_GlobalInterrupt();
}
i=DnsQuery(SOCK_DNS,url_dn1,ip); //DNS域名解析
if(i)
{
printf("Domain name: %s \n",url_dn1);
printf(" HTTPs_IP= %d.%d.%d.%d\n\n",ip[0],ip[1],ip[2],ip[3]);
status = 1;
break;
}
}
}
二、应用：
将CH394设备接入路由中，运行日志如下，可以看到默认IP是192.168.1.200，DHCP成功后的IP为192.168.1.139，再进行DNS解析百度域名，解析完成后IP地址为180.101.50.242.
例程链接： https://files.cnblogs.com/files/blogs/805237/CH394Q_DHCP%26DNS.rar?t=1733989245&download=true
标签：ip,CH394,以太网,dhcp,printf,DHCP,CH394Q,allocated From： https://www.cnblogs.com/sw111/p/18600039