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项目基于udp通信的聊天室

web 2025/5/15 6:08:32

udp.h

#ifndef _UDP_H_
#define _UDP_H_#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>#define M 32       // 用户名最大长度
#define N 1024     // 消息内容最大长度
#define ERRLOG(msg) do { perror(msg); exit(-1); } while(0)// 消息结构体（包含操作码、用户名、消息内容）
typedef struct {char code;          // 操作码：'d'登录 'q'群聊 't'退出char user[M];       // 用户名char text[N];       // 消息内容（群聊内容/系统消息）
} msg_t;// 链表节点结构体（存储客户端地址信息）
typedef struct node {struct sockaddr_in addr;  // 客户端socket地址struct node *next;        // 指向下一个节点
} node_t;#endif

server.c

#include "udp.h"// 创建链表头节点
int create_node(node_t **phead) {*phead = (node_t *)malloc(sizeof(node_t));if (*phead == NULL) {ERRLOG("内存分配失败");}(*phead)->next = NULL;return 0;
}// 尾插法插入客户端节点
int insert_node(node_t *phead, struct sockaddr_in addr) {node_t *pnew = NULL;create_node(&pnew);pnew->addr = addr;node_t *ptemp = phead;while (ptemp->next != NULL) {ptemp = ptemp->next;}ptemp->next = pnew;return 0;
}// 删除指定客户端节点
int delete_node(node_t *phead, struct sockaddr_in addr) {node_t *prev = phead;node_t *curr = phead->next;while (curr != NULL) {if (memcmp(&curr->addr, &addr, sizeof(addr)) == 0) {prev->next = curr->next;free(curr);return 0;}prev = curr;curr = curr->next;}return -1;
}int main(int argc, const char *argv[]) {if (argc != 3) {printf("Usage: %s <IP> <port>\n", argv[0]);return -1;}// 创建UDP套接字int sockfd = socket(AF_INET, SOCK_DGRAM, 0);if (sockfd == -1) {ERRLOG("socket创建失败");}// 绑定服务器地址struct sockaddr_in serveraddr;memset(&serveraddr, 0, sizeof(serveraddr));serveraddr.sin_family = AF_INET;serveraddr.sin_port = htons(atoi(argv[2]));serveraddr.sin_addr.s_addr = inet_addr(argv[1]);if (bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) == -1) {ERRLOG("bind失败");}printf("服务器启动，监听 %s:%d\n", argv[1], atoi(argv[2]));// 初始化客户端链表node_t *phead;create_node(&phead);pid_t pid = fork();if (pid < 0) {ERRLOG("fork失败");} else if (pid == 0) {  // 子进程：处理客户端消息接收与广播struct sockaddr_in clientaddr;socklen_t client_len = sizeof(clientaddr);msg_t msg;while (1) {memset(&msg, 0, sizeof(msg));if (recvfrom(sockfd, &msg, sizeof(msg), 0, (struct sockaddr *)&clientaddr, &client_len) == -1) {ERRLOG("recvfrom失败");}switch (msg.code) {case 'd':  // 登录处理printf("[%s] 上线\n", msg.user);insert_node(phead, clientaddr);  // 添加到在线列表// 广播登录通知（排除自己）node_t *p = phead->next;while (p != NULL) {if (memcmp(&p->addr, &clientaddr, sizeof(clientaddr)) != 0) {sendto(sockfd, &msg, sizeof(msg), 0, (struct sockaddr *)&p->addr, sizeof(p->addr));}p = p->next;}break;case 'q':  // 群聊处理if (strcmp(msg.user, "管理员") != 0) {  // 非管理员消息打印printf("[%s]: %s\n", msg.user, msg.text);}// 广播群聊消息（包括自己，UDP无连接需全播）node_t *q = phead->next;while (q != NULL) {sendto(sockfd, &msg, sizeof(msg), 0, (struct sockaddr *)&q->addr, sizeof(q->addr));q = q->next;}break;case 't':  // 退出处理printf("[%s] 下线\n", msg.user);delete_node(phead, clientaddr);  // 从列表删除// 广播退出通知node_t *r = phead->next;while (r != NULL) {sendto(sockfd, &msg, sizeof(msg), 0, (struct sockaddr *)&r->addr, sizeof(r->addr));r = r->next;}break;}}} else {  // 父进程：发送系统消息（以"管理员"身份）msg_t sys_msg;while (1) {memset(&sys_msg, 0, sizeof(sys_msg));strcpy(sys_msg.user, "管理员");fgets(sys_msg.text, N, stdin);sys_msg.text[strlen(sys_msg.text) - 1] = '\0';  // 去除换行符sys_msg.code = 'q';  // 系统消息以群聊码发送// 广播系统消息给所有在线客户端node_t *s = phead->next;while (s != NULL) {sendto(sockfd, &sys_msg, sizeof(sys_msg), 0, (struct sockaddr *)&s->addr, sizeof(s->addr));s = s->next;}}}close(sockfd);return 0;
}

client.c

#include "udp.h"int main(int argc, const char *argv[]) {if (argc != 3) {printf("Usage: %s <服务器IP> <端口>\n", argv[0]);return -1;}// 创建UDP套接字int sockfd = socket(AF_INET, SOCK_DGRAM, 0);if (sockfd == -1) {ERRLOG("socket创建失败");}// 服务器地址struct sockaddr_in serveraddr;memset(&serveraddr, 0, sizeof(serveraddr));serveraddr.sin_family = AF_INET;serveraddr.sin_port = htons(atoi(argv[2]));serveraddr.sin_addr.s_addr = inet_addr(argv[1]);socklen_t server_len = sizeof(serveraddr);// 登录：发送用户名msg_t msg;char username[M] = {0};printf("请输入用户名（退出输入quit）: ");fgets(username, M, stdin);username[strlen(username) - 1] = '\0';  // 去除换行符if (strcmp(username, "quit") == 0) {printf("未登录，退出程序\n");close(sockfd);return 0;}msg.code = 'd';strcpy(msg.user, username);if (sendto(sockfd, &msg, sizeof(msg), 0, (struct sockaddr *)&serveraddr, server_len) == -1) {ERRLOG("登录消息发送失败");}pid_t pid = fork();if (pid < 0) {ERRLOG("fork失败");} else if (pid == 0) {  // 子进程：接收服务器广播消息msg_t recv_msg;while (1) {memset(&recv_msg, 0, sizeof(recv_msg));if (recvfrom(sockfd, &recv_msg, sizeof(recv_msg), 0, (struct sockaddr *)&serveraddr, &server_len) == -1) {ERRLOG("recvfrom失败");}// 过滤自己的登录/退出通知（UDP广播会收到自己的消息）if (strcmp(recv_msg.user, username) == 0 && (recv_msg.code == 'd' || recv_msg.code == 't')) {continue;}switch (recv_msg.code) {case 'd': printf("[%s] 登录上线\n", recv_msg.user); break;case 'q': printf("[%s]: %s\n", recv_msg.user, recv_msg.text); break;case 't': printf("[%s] 退出聊天\n", recv_msg.user); break;}}} else {  // 父进程：发送群聊消息或退出while (1) {memset(msg.text, 0, N);fgets(msg.text, N, stdin);msg.text[strlen(msg.text) - 1] = '\0';  // 去除换行符if (strcmp(msg.text, "quit") == 0) {  // 退出操作msg.code = 't';sendto(sockfd, &msg, sizeof(msg), 0, (struct sockaddr *)&serveraddr, server_len);break;} else {  // 群聊消息msg.code = 'q';sendto(sockfd, &msg, sizeof(msg), 0, (struct sockaddr *)&serveraddr, server_len);}}}close(sockfd);return 0;
}