---
title: "Clion IDE-STM32+W5500 (DHCP code encapsulation)"
url: "https://maker.wiznet.io/mark/projects/clion-ide-stm32-w5500-dhcp-code-encapsulation/"
markdown_url: "https://maker.wiznet.io/mark/projects/clion-ide-stm32-w5500-dhcp-code-encapsulation/md"
type: "UCC: User Created Content"
author: "詩不诉卿"
author_url: "https://blog.csdn.net/weixin_44742767/article/details/131696673?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522169232443716777224450804%2522%252C%2522scm%2522%253A%252220140713.130102334.pc%255Fall.%2522%257D&request_id=169232443716777224450804&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~all~first_rank_ecpm_v1~times_rank-1-131696673-null-null.142%5ev93%5echatsearchT3_2&utm_term=W5500&spm=1018.2226.3001.4187"
editor: "WIZnet"
editor_url: "https://maker.wiznet.io/"
original_author: "詩不诉卿"
original_url: "https://blog.csdn.net/weixin_44742767/article/details/131696673?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522169232443716777224450804%2522%252C%2522scm%2522%253A%252220140713.130102334.pc%255Fall.%2522%257D&request_id=169232443716777224450804&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~all~first_rank_ecpm_v1~times_rank-1-131696673-null-null.142%5ev93%5echatsearchT3_2&utm_term=W5500&spm=1018.2226.3001.4187"
published: "2023-10-04"
language: "en"
likes: 0
views: 251
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# Clion IDE-STM32+W5500 (DHCP code encapsulation)

> Clion IDE-STM32+W5500 (DHCP code encapsulation)

Original author: 詩不诉卿 (source: https://blog.csdn.net/weixin_44742767/article/details/131696673?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522169232443716777224450804%2522%252C%2522scm%2522%253A%252220140713.130102334.pc%255Fall.%2522%257D&request_id=169232443716777224450804&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~all~first_rank_ecpm_v1~times_rank-1-131696673-null-null.142%5ev93%5echatsearchT3_2&utm_term=W5500&spm=1018.2226.3001.4187)

## Article

**Clion IDE-STM32+W5500(DHCP code encapsulation)Header file:**

#ifndef STM32_VET6_W5500_DHCP_H
#define STM32_VET6_W5500_DHCP_H

#include "w5500_dhcp_struct.h"
#include "socket.h"

#define DEVICE_ID "w5500"
#define IP_CONFLICT_STR "CHECK_IP_CONFLICT"
#define DHCP_FLAGSBROADCAST 0x8000
/* UDP port numbers for DHCP */
#define DHCP_SERVER_PORT 67 /* from server to client */
#define DHCP_CLIENT_PORT 68 /* from client to server */
/* DHCP message OP code */
#define DHCP_BOOTREQUEST 1
#define DHCP_BOOTREPLY 2
/* DHCP message type */
#define DHCP_DISCOVER 1
#define DHCP_OFFER 2
#define DHCP_REQUEST 3
#define DHCP_DECLINE 4
#define DHCP_ACK 5
#define DHCP_NAK 6
#define DHCP_RELEASE 7
#define DHCP_INFORM 8
#define DHCP_HTYPE10MB 1
#define DHCP_HTYPE100MB 2
#define DHCP_HLENETHERNET 6
#define DHCP_HOPS 0
#define DHCP_SECS 0
#define MAGIC_COOKIE 0x63825363
#define DEFAULT_XID 0x12345678
#define MAX_DHCP_OPT 16

void dhcp_init();

void dhcp_config_registry(module_w5500_t *conf);

bool do_dhcp(SOCKET s, uint32_t wait_ms);

#endif //STM32_VET6_W5500_DHCP_H

**Source file:**

#include "w5500_dhcp.h"

#define DBG_ENABLE
#define DBG_SECTION_NAME "dhcp"
#define DBG_LEVEL DBG_INFO

#include "sys_dbg.h"

uint8_t EXTERN_DHCPBUF[1024];
RIP_MSG *pRIPMSG = (RIP_MSG *) EXTERN_DHCPBUF; /*DHCP消息指针*/
uint32_t DHCP_XID = DEFAULT_XID;

uint8_t OLD_SIP[4]; /*最初获取到的IP地址*/
uint8_t DHCP_SIP[4] = {0}; /*已发现的DNS服务器地址*/
uint8_t DHCP_REAL_SIP[4] = {0};/*从DHCP列表中选择使用的DHCP服务器*/

static module_w5500_t *w5500_ptr;

uint32_t dhcp_lease_time; /*租约时间*/

void send_DHCP_DISCOVER(SOCKET s); /*向DHCP服务器发送发现报文*/
void send_DHCP_REQUEST(SOCKET s, uint8_t pkt_type); /*向DHCP服务器发送请求报文*/
void send_DHCP_RELEASE_DECLINE(SOCKET s, char msgtype); /*向DHCP服务器发送释放报文*/

uint8_t parseDHCPMSG(SOCKET s, uint16_t length);

uint8_t check_leasedIP(SOCKET s); /*检查获取的IP是否冲突*/
uint8_t *SRC_MAC_ADDR = NULL; /*本地MAC地址*/
uint8_t *GET_SIP = NULL; /*从DHCP服务器获取到的本机IP*/
uint8_t *GET_GW_IP = NULL; /*从DHCP服务器获取到的网关地址*/
uint8_t *GET_SN_MASK = NULL; /*从DHCP服务器获取到的子网掩码*/
uint8_t GET_DNS_IP[4] = {0}; /*从DHCP服务器获取到的DNS服务器地址*/
void dhcp_config_registry(module_w5500_t *conf) {
w5500_ptr = conf;
GET_SIP = conf->net_conf.ip;
GET_SN_MASK = conf->net_conf.sub;
SRC_MAC_ADDR = conf->net_conf.mac;
GET_GW_IP = conf->net_conf.gw;
}

void dhcp_init() {
/*该引脚需要保持低电平至少 500 us，才能重置 W5500；*/
w5500_ptr->driver.rst_low();
w5500_ptr->driver.delay(3);
w5500_ptr->driver.rst_high();
w5500_ptr->driver.delay(1600);
w5500_chip_init();
/*设置mac地址*/
w5500_writes(MAC_ADDR, w5500_ptr->net_conf.mac, 6);
/*初始化Socket的发送接收缓存大小*/
for (uint8_t i = 0; i < w5500_ptr->base_conf.socket_num; i++) {
w5500_write(Sn_TXMEM_SIZE(i), w5500_ptr->base_conf.tx_size[i]);
w5500_write(Sn_RXMEM_SIZE(i), w5500_ptr->base_conf.rx_size[i]);
}
}

uint16_t wait_DHCP_Response(SOCKET s, uint32_t timeout_ms) {
uint16_t len = 0;
for (int i = 0; i < timeout_ms / 10; ++i) {
w5500_ptr->driver.delay(10);
len = w5500_socket_rx_size_read(s);
if (len > 0) {
return parseDHCPMSG(s, len);
}

}
return 0;
}

bool do_dhcp(SOCKET s, uint32_t wait_ms) {
uint16_t type;
if (udp_client_init(s, DHCP_CLIENT_PORT)) {
// 01-发送DISCOVER包
send_DHCP_DISCOVER(s);
// 02-等待响应
type = wait_DHCP_Response(s, wait_ms);
if (type == DHCP_OFFER) {
send_DHCP_REQUEST(s, STATE_DHCP_REQUEST); /*发送REQUEST包*/

type = wait_DHCP_Response(s, wait_ms);
if (type == DHCP_ACK) {
LOG_D("dhcp_lease_time is %d", dhcp_lease_time);
if (check_leasedIP(s)) {
memcpy(OLD_SIP, GET_SIP, 4);
DHCP_XID++;
send_DHCP_REQUEST(s, STATE_DHCP_LEASED);
type = wait_DHCP_Response(s, wait_ms);
if (type != DHCP_ACK && type != 0) {
LOG_W("release dhcp connect error:%d", type);
}
LOG_D("config ip start");
w5500_writes(SUB_ADDR, w5500_ptr->net_conf.sub, 4); /*子网掩码*/
w5500_writes(GAR_ADDR, w5500_ptr->net_conf.gw, 4); /*网关*/
w5500_writes(SIPR_ADDR, w5500_ptr->net_conf.ip, 4); /*IP配置*/
LOG_I("<DHCP GET IP OK>");
LOG_I("IP:%d.%d.%d.%d", w5500_ptr->net_conf.ip[0], w5500_ptr->net_conf.ip[1],
w5500_ptr->net_conf.ip[2], w5500_ptr->net_conf.ip[3]);
return true;
} else {
LOG_W("state : DHCP_RET_CONFLICT");
}
} else if (type == DHCP_NAK) {
LOG_W("send_DHCP_REQUEST is DHCP_NAK ");
}
}
}
return false;
}

uint8_t check_leasedIP(SOCKET s) {
LOG_D("<Check the IP Conflict %d.%d.%d.%d: ", GET_SIP[0], GET_SIP[1], GET_SIP[2], GET_SIP[3]);
if (sendto(s, (uint8_t *) IP_CONFLICT_STR, strlen(IP_CONFLICT_STR), GET_SIP, 5000)) {
send_DHCP_RELEASE_DECLINE(s, 1);
return 0;
}
return 1;
}

/**
*@brief 解析获得的DHCP消息
*@param length:解析消息长度
*@return 0：解析失败 其他：解析成功
*/
uint8_t parseDHCPMSG(SOCKET s, uint16_t length) {
uint8_t svr_addr[6];
uint16_t svr_port;
uint16_t len;
uint8_t *p;
uint8_t *e;
uint8_t type;
uint8_t opt_len = 0;

len = recvfrom(s, (uint8_t *) pRIPMSG, length, svr_addr, &svr_port);

LOG_D("DHCP_SIP:%u.%u.%u.%u", DHCP_SIP[0], DHCP_SIP[1], DHCP_SIP[2], DHCP_SIP[3]);
LOG_D("DHCP_RIP:%u.%u.%u.%u", DHCP_REAL_SIP[0], DHCP_REAL_SIP[1], DHCP_REAL_SIP[2], DHCP_REAL_SIP[3]);
LOG_D("svr_addr:%u.%u.%u.%u", svr_addr[0], svr_addr[1], svr_addr[2], svr_addr[3]);

if (pRIPMSG->op != DHCP_BOOTREPLY || svr_port != DHCP_SERVER_PORT) {
LOG_D("DHCP : NO DHCP MSG");
return 0;
}
if (memcmp(pRIPMSG->chaddr, SRC_MAC_ADDR, 6) != 0 || pRIPMSG->xid != htonl(DHCP_XID)) {
LOG_W("No My DHCP Message. This message is ignored.");
LOG_W("\tSRC_MAC_ADDR(%02X.%02X.%02X.%02X.%02X.%02X)",
SRC_MAC_ADDR[0], SRC_MAC_ADDR[1], SRC_MAC_ADDR[2],
SRC_MAC_ADDR[3], SRC_MAC_ADDR[4], SRC_MAC_ADDR[5]);
LOG_W(", pRIPMSG->chaddr(%02X.%02X.%02X.", (char) pRIPMSG->chaddr[0], (char) pRIPMSG->chaddr[1],
(char) pRIPMSG->chaddr[2]);
LOG_W("%02X.%02X.%02X)", pRIPMSG->chaddr[3], pRIPMSG->chaddr[4], pRIPMSG->chaddr[5]);
LOG_W("\tpRIPMSG->xid(%08X), DHCP_XID(%08X)", pRIPMSG->xid, (DHCP_XID));
LOG_W("\tpRIMPMSG->yiaddr:%d.%d.%d.%d", pRIPMSG->yiaddr[0], pRIPMSG->yiaddr[1], pRIPMSG->yiaddr[2],
pRIPMSG->yiaddr[3]);
return 0;
}

if (*((uint32_t *) DHCP_SIP) != 0x00000000) {
if (*((uint32_t *) DHCP_REAL_SIP) != *((uint32_t *) svr_addr) &&
*((uint32_t *) DHCP_SIP) != *((uint32_t *) svr_addr)) {
LOG_D("Another DHCP sever send a response message. This is ignored.");
LOG_D("\tIP:%u.%u.%u.%u", svr_addr[0], svr_addr[1], svr_addr[2], svr_addr[3]);
return 0;
}
}
memcpy(GET_SIP, pRIPMSG->yiaddr, 4);

LOG_D("DHCP MSG received");
LOG_D("yiaddr : %u.%u.%u.%u", GET_SIP[0], GET_SIP[1], GET_SIP[2], GET_SIP[3]);
type = 0;
p = (uint8_t *) (&pRIPMSG->op);
p = p + 240;
e = p + (len - 240);
LOG_D("p : %08X e : %08X len : %d", (uint32_t) p, (uint32_t) e, len);
while (p < e) {
switch (*p++) {
case endOption:
return type;
case padOption:
break;
case dhcpMessageType:
opt_len = *p++;
type = *p;
LOG_D("dhcpMessageType : %02X", type);
break;

case subnetMask:
opt_len = *p++;
memcpy(GET_SN_MASK, p, 4);
break;

case routersOnSubnet:
opt_len = *p++;
memcpy(GET_GW_IP, p, 4);
break;

case dns:
opt_len = *p++;
memcpy(GET_DNS_IP, p, 4);
break;

case dhcpIPaddrLeaseTime:
opt_len = *p++;
dhcp_lease_time = ntohl(*((uint32_t *) p));
break;

case dhcpServerIdentifier:
opt_len = *p++;
if (*((uint32_t *) DHCP_SIP) == 0 ||
*((uint32_t *) DHCP_REAL_SIP) == *((uint32_t *) svr_addr) ||
*((uint32_t *) DHCP_SIP) == *((uint32_t *) svr_addr)) {
memcpy(DHCP_SIP, p, 4);
memcpy(DHCP_REAL_SIP, svr_addr, 4); // Copy the real ip address of my DHCP server
LOG_D("My dhcpServerIdentifier : %u.%u.%u.%u",
DHCP_SIP[0], DHCP_SIP[1], DHCP_SIP[2], DHCP_SIP[3]);
LOG_D("My DHCP server real IP address :%u.%u.%u.%u",
DHCP_REAL_SIP[0], DHCP_REAL_SIP[1], DHCP_REAL_SIP[2], DHCP_REAL_SIP[3]);
} else {
LOG_D("Another dhcpServerIdentifier : MY(%u.%u.%u.%u) Another(%u.%u.%u.%u)",
DHCP_SIP[0], DHCP_SIP[1], DHCP_SIP[2], DHCP_SIP[3],
svr_addr[0], svr_addr[1], svr_addr[2], svr_addr[3]);
}
break;
default:
opt_len = *p++;
break;
} // switch
p += opt_len;
} // while
return 0;
}

/**
*@brief 发送DISCOVER信息给DHCP服务器
*@param 无
*@return 无
*/
void send_DHCP_DISCOVER(SOCKET s) {
uint8_t ip[4] = {255, 255, 255, 255};
uint16_t i = 0;
// the host name modified
uint8_t host_name[12];
memset((void *) pRIPMSG, 0, sizeof(RIP_MSG)); /*清空pRIPMSG的 sizeof(RIP_MSG) 个空间*/
pRIPMSG->op = DHCP_BOOTREQUEST;
pRIPMSG->htype = DHCP_HTYPE10MB;
pRIPMSG->hlen = DHCP_HLENETHERNET;
pRIPMSG->hops = DHCP_HOPS;
pRIPMSG->xid = htonl(DHCP_XID);
pRIPMSG->secs = htons(DHCP_SECS);
pRIPMSG->flags = htons(DHCP_FLAGSBROADCAST);
/*mac地址*/
memcpy(pRIPMSG->chaddr, SRC_MAC_ADDR, 6);
/* MAGIC_COOKIE */
pRIPMSG->OPT[i++] = (uint8_t) ((MAGIC_COOKIE >> 24) & 0xFF);
pRIPMSG->OPT[i++] = (uint8_t) ((MAGIC_COOKIE >> 16) & 0xFF);
pRIPMSG->OPT[i++] = (uint8_t) ((MAGIC_COOKIE >> 8) & 0xFF);
pRIPMSG->OPT[i++] = (uint8_t) (MAGIC_COOKIE & 0xFF);

/* Option Request Param. */
pRIPMSG->OPT[i++] = dhcpMessageType;
pRIPMSG->OPT[i++] = 0x01;
pRIPMSG->OPT[i++] = DHCP_DISCOVER;

/*Client identifier*/
pRIPMSG->OPT[i++] = dhcpClientIdentifier;
pRIPMSG->OPT[i++] = 0x07;
pRIPMSG->OPT[i++] = 0x01;

memcpy(pRIPMSG->OPT + i, SRC_MAC_ADDR, 6);
i += 6;
// host name
pRIPMSG->OPT[i++] = hostName;
// set the host name
sprintf((char *) host_name, "%.4s-%02X%02X%02X", DEVICE_ID,
SRC_MAC_ADDR[3], SRC_MAC_ADDR[4], SRC_MAC_ADDR[5]);

pRIPMSG->OPT[i++] = (uint8_t) strlen((char *) host_name);

strcpy((char *) (&(pRIPMSG->OPT[i])), (char *) host_name);

i += (uint16_t) strlen((char *) host_name);

pRIPMSG->OPT[i++] = dhcpParamRequest;
pRIPMSG->OPT[i++] = 0x06;
pRIPMSG->OPT[i++] = subnetMask;
pRIPMSG->OPT[i++] = routersOnSubnet;
pRIPMSG->OPT[i++] = dns;
pRIPMSG->OPT[i++] = domainName;
pRIPMSG->OPT[i++] = dhcpT1value;
pRIPMSG->OPT[i++] = dhcpT2value;
pRIPMSG->OPT[i++] = endOption;
/* send broadcasting packet */
sendto(s, (uint8_t *) pRIPMSG, sizeof(RIP_MSG), ip, DHCP_SERVER_PORT);
LOG_D("sent DHCP_DISCOVER");
}

void send_DHCP_REQUEST(SOCKET s, uint8_t pkt_type) {
uint8_t ip[4], host_name[12];
uint16_t i = 0;
memset((void *) pRIPMSG, 0, sizeof(RIP_MSG));
pRIPMSG->op = DHCP_BOOTREQUEST;
pRIPMSG->htype = DHCP_HTYPE10MB;
pRIPMSG->hlen = DHCP_HLENETHERNET;
pRIPMSG->hops = DHCP_HOPS;
pRIPMSG->xid = htonl(DHCP_XID);
pRIPMSG->secs = htons(DHCP_SECS);

if (pkt_type < STATE_DHCP_LEASED)
pRIPMSG->flags = htons(DHCP_FLAGSBROADCAST);
else {
pRIPMSG->flags = 0; // For Unicast
memcpy(pRIPMSG->ciaddr, GET_SIP, 4);
}

memcpy(pRIPMSG->chaddr, SRC_MAC_ADDR, 6);

/* MAGIC_COOKIE */
pRIPMSG->OPT[i++] = (uint8_t) ((MAGIC_COOKIE >> 24) & 0xFF);
pRIPMSG->OPT[i++] = (uint8_t) ((MAGIC_COOKIE >> 16) & 0xFF);
pRIPMSG->OPT[i++] = (uint8_t) ((MAGIC_COOKIE >> 8) & 0xFF);
pRIPMSG->OPT[i++] = (uint8_t) (MAGIC_COOKIE & 0xFF);

/* Option Request Param. */
pRIPMSG->OPT[i++] = dhcpMessageType;
pRIPMSG->OPT[i++] = 0x01;
pRIPMSG->OPT[i++] = DHCP_REQUEST;

pRIPMSG->OPT[i++] = dhcpClientIdentifier;
pRIPMSG->OPT[i++] = 0x07;
pRIPMSG->OPT[i++] = 0x01;
memcpy(pRIPMSG->OPT + i, SRC_MAC_ADDR, 6);
i += 6;
if (pkt_type < STATE_DHCP_LEASED) {
pRIPMSG->OPT[i++] = dhcpRequestedIPaddr;
pRIPMSG->OPT[i++] = 0x04;
memcpy(pRIPMSG->OPT + i, GET_SIP, 4);
i += 4;
pRIPMSG->OPT[i++] = dhcpServerIdentifier;
pRIPMSG->OPT[i++] = 0x04;
memcpy(pRIPMSG->OPT + i, DHCP_SIP, 4);
i += 4;
}
// host name
pRIPMSG->OPT[i++] = hostName;
// set the host name
sprintf((char *) host_name, (char *) "%.4s-%02X%02X%02X", DEVICE_ID, SRC_MAC_ADDR[3], SRC_MAC_ADDR[4],
SRC_MAC_ADDR[5]);
pRIPMSG->OPT[i++] = (uint8_t) strlen((char *) host_name);
strcpy((char *) &(pRIPMSG->OPT[i]), (char *) host_name);
i += strlen((char *) host_name);
pRIPMSG->OPT[i++] = dhcpParamRequest;
pRIPMSG->OPT[i++] = 0x08;
pRIPMSG->OPT[i++] = subnetMask;
pRIPMSG->OPT[i++] = routersOnSubnet;
pRIPMSG->OPT[i++] = dns;
pRIPMSG->OPT[i++] = domainName;
pRIPMSG->OPT[i++] = dhcpT1value;
pRIPMSG->OPT[i++] = dhcpT2value;
pRIPMSG->OPT[i++] = performRouterDiscovery;
pRIPMSG->OPT[i++] = staticRoute;
pRIPMSG->OPT[i++] = endOption;
/* send broadcasting packet */
if (pkt_type < STATE_DHCP_LEASED)
memset(ip, 0xFF, 4);
else
memcpy(ip, DHCP_SIP, 4);
sendto(s, (uint8_t *) pRIPMSG, sizeof(RIP_MSG), ip, DHCP_SERVER_PORT);
LOG_D("sent DHCP_REQUEST");
}

void send_DHCP_RELEASE_DECLINE(SOCKET s, char msgtype) {
uint16_t i = 0;
uint8_t ip[4];
memset((void *) pRIPMSG, 0, sizeof(RIP_MSG));
pRIPMSG->op = DHCP_BOOTREQUEST;
pRIPMSG->htype = DHCP_HTYPE10MB;
pRIPMSG->hlen = DHCP_HLENETHERNET;
pRIPMSG->hops = DHCP_HOPS;
pRIPMSG->xid = htonl(DHCP_XID);
pRIPMSG->secs = htons(DHCP_SECS);
pRIPMSG->flags = 0; // DHCP_FLAGSBROADCAST;
memcpy(pRIPMSG->chaddr, SRC_MAC_ADDR, 6);

/* MAGIC_COOKIE */
pRIPMSG->OPT[i++] = (uint8_t) ((MAGIC_COOKIE >> 24) & 0xFF);
pRIPMSG->OPT[i++] = (uint8_t) ((MAGIC_COOKIE >> 16) & 0xFF);
pRIPMSG->OPT[i++] = (uint8_t) ((MAGIC_COOKIE >> 8) & 0xFF);
pRIPMSG->OPT[i++] = (uint8_t) (MAGIC_COOKIE & 0xFF);

/* Option Request Param. */
pRIPMSG->OPT[i++] = dhcpMessageType;
pRIPMSG->OPT[i++] = 0x01;
pRIPMSG->OPT[i++] = ((!msgtype) ? DHCP_RELEASE : DHCP_DECLINE);

pRIPMSG->OPT[i++] = dhcpClientIdentifier;
pRIPMSG->OPT[i++] = 0x07;
pRIPMSG->OPT[i++] = 0x01;
memcpy(pRIPMSG->OPT + i, SRC_MAC_ADDR, 6);
i += 6;
pRIPMSG->OPT[i++] = dhcpServerIdentifier;
pRIPMSG->OPT[i++] = 0x04;
pRIPMSG->OPT[i++] = DHCP_SIP[0];
pRIPMSG->OPT[i++] = DHCP_SIP[1];
pRIPMSG->OPT[i++] = DHCP_SIP[2];
pRIPMSG->OPT[i++] = DHCP_SIP[3];

if (msgtype) {
pRIPMSG->OPT[i++] = dhcpRequestedIPaddr;
pRIPMSG->OPT[i++] = 0x04;
pRIPMSG->OPT[i++] = GET_SIP[0];
pRIPMSG->OPT[i++] = GET_SIP[1];
pRIPMSG->OPT[i++] = GET_SIP[2];
pRIPMSG->OPT[i++] = GET_SIP[3];
LOG_D("sent DHCP_DECLINE\r\n");
} else {
LOG_D("sent DHCP_RELEASE");
}

pRIPMSG->OPT[i++] = endOption;

if (msgtype)
memset(ip, 0xFF, 4);
else
memcpy(ip, DHCP_SIP, 4);
// printf("send dhcp decline\r\n");
sendto(s, (uint8_t *) pRIPMSG, sizeof(RIP_MSG), ip, DHCP_SERVER_PORT);
}

**Testing:**

/***
* Copyright (c) [scl]。保留所有权利。
* 本文仅供个人学习和研究使用，禁止用于商业用途。
**/

#include "app_conf.h"
#include "w5500_config.h"

#if APP_CONFIG_W5500_DHCP
#define DBG_ENABLE
#define DBG_SECTION_NAME "w5500"
#define DBG_LEVEL W5500_DBG_LEVEL

#include "sys_dbg.h"
#include "w5500_dhcp.h"

#define W5500_CS stm_port_define(B,12)
#define W5500_RST stm_port_define(B,10)
static SPI_HandleTypeDef *w5500_spi = NULL;

static void send_and_rec_bytes(uint8_t *in_dat, uint8_t *out_data, uint16_t len) {
if (in_dat == NULL && out_data == NULL) return;
uint8_t *p_tx = in_dat;
uint8_t *p_rx = out_data;
if (p_rx == NULL) {
HAL_SPI_Transmit(w5500_spi, p_tx, len, 10);
} else {
if (p_tx == NULL) {
p_tx = p_rx;
}
HAL_SPI_TransmitReceive(w5500_spi, p_tx, p_rx, len, 10);
}

}

static void W5500_RST_HIGH(void) { stm_pin_high(GPIOB, GPIO_PIN_10); }

static void W5500_RST_LOW(void) { stm_pin_low(GPIOB, GPIO_PIN_10); }

static void W5500_CS_LOW(void) { stm_pin_low(GPIOB, GPIO_PIN_12); }

static void W5500_CS_HIGH(void) { stm_pin_high(GPIOB, GPIO_PIN_12); }

static void W5500_Driver_MspInit(void) {
stm32_pin_mode(W5500_CS, pin_mode_output); /*CS*/
stm32_pin_mode(W5500_RST, pin_mode_output); /*RST*/
stm_pin_low(W5500_RST);
stm_pin_low(W5500_CS);
/*初始化SPI外设*/
/*W5500 支持 SPI 模式 0 及模式 3..MOSI 和 MISO 信号无论是接收或发送，均遵从从最高标志位（MSB）到最低标志位（LSB）的传输序列。*/
bsp_SpiHandleInit(w5500_spi, SPI_BAUDRATEPRESCALER_4, spi_mode_0);
}

module_w5500_t w5500_conf = {
.base_conf={
.socket_num = 4,
.rx_size={4, 4, 4, 4},
.tx_size={4, 4, 4, 4},
},
.net_conf={
// .ip={192, 168, 199, 12},
// .gw={192, 168, 199, 1},
// .sub={255, 255, 255, 0},
},
.driver={
.cs_high = W5500_CS_HIGH,
.cs_low = W5500_CS_LOW,
.rst_high= W5500_RST_HIGH,
.rst_low=W5500_RST_LOW,
.delay = HAL_Delay,
.send_and_rec_bytes = send_and_rec_bytes
},
.api = {
.msp_init=W5500_Driver_MspInit,
}
};

static void w5500_pre_init(void) {
/*一般做数据加载，此时系统时钟使用的是内部时钟，如需要使用系统时钟的外设不在此进行初始化*/
w5500_spi = conv_spi_handle_ptr(handle_get_by_id(spi2_id));
/*初始化资源*/
module_w5500_init(&w5500_conf);
uint32_t uid0 = HAL_GetUIDw0();
uint32_t uid1 = HAL_GetUIDw1();
uint32_t uid2 = HAL_GetUIDw2();
uint8_t mac[6] = {0, uid0 >> 8, uid1, uid1 >> 8, uid2, uid2 >> 8};
memcpy(w5500_conf.net_conf.mac, mac, sizeof(mac));
dhcp_config_registry(&w5500_conf);
w5500_conf.net_conf_init = dhcp_init;/*使用dhcp init*/
}

static void w5500_init(void) {

w5500_conf.api.msp_init();/*初始化*/

}

static void w5500_after_init(void) {
w5500_conf.net_conf_init();
printf("w5500 invoke after\r\n");
uint16_t try_cnt = 0;
while (!do_dhcp(0, 0x1000)) {
if (try_cnt > 20) {
LOG_D("try timeout");
break;
}
try_cnt++;
}

}

app_init_export(w5500_net_conf, w5500_pre_init, w5500_init, w5500_after_init);

#endif

**Result:**

![](https://maker.wiznet.io/upload/ckeditor5/480201412%5F1696419553%2Epng)

![](https://maker.wiznet.io/upload/ckeditor5/480201412%5F1696419570%2Epng)

---

Source: https://maker.wiznet.io/mark/projects/clion-ide-stm32-w5500-dhcp-code-encapsulation/