UDP网络聊天室

服务器端（未完成）

#include <header.h>
#define MAX_CLIENTS 100
#define MESSAGE_SIZE 1024
typedef struct node 
{char name[20];struct sockaddr_in client;struct node *next;
} node, *node_p;node_p create_link() 
{node_p H = (node_p)malloc(sizeof(node));if (H == NULL) {printf("申请内存失败\n");return NULL;}H->next = NULL;return H;
}node_p create_node(char *name, struct sockaddr_in client) 
{node_p new = (node_p)malloc(sizeof(node));if (new == NULL){printf("申请内存失败\n");return NULL;}strcpy(new->name, name);new->client = client;new->next = NULL;return new;
}void insert(node_p H, char *name, struct sockaddr_in client) 
{if (H == NULL) {printf("链表头节点为空\n");return;}node_p new = create_node(name, client);new->next = H->next;H->next = new;
}void remove_node(node_p H, struct sockaddr_in client)
{if (H == NULL) {printf("链表头节点为空\n");return;}node_p prev = H;node_p curr = H->next;while (curr != NULL){if (curr->client.sin_addr.s_addr == client.sin_addr.s_addr &&curr->client.sin_port == client.sin_port) {prev->next = curr->next;free(curr);return;}prev = curr;curr = curr->next;}
}void broadcast_message(int sfd, node_p H, char *message, struct sockaddr_in *exclude_client) 
{node_p curr = H->next;while (curr != NULL) {if (exclude_client == NULL || curr->client.sin_addr.s_addr != exclude_client->sin_addr.s_addr ||curr->client.sin_port != exclude_client->sin_port) {sendto(sfd, message, strlen(message), 0, (struct sockaddr*)&curr->client, sizeof(curr->client));}curr = curr->next;}
}int main(int argc, char *argv[]) 
{int sfd = socket(AF_INET, SOCK_DGRAM, 0);if (sfd == -1) {perror("socket");return 1;}char *server_ip=argv[1];int server_port=atoi(argv[2]);struct sockaddr_in sin;sin.sin_family = AF_INET;sin.sin_port = htons(server_port);sin.sin_addr.s_addr = inet_addr(server_ip);if (bind(sfd, (struct sockaddr*)&sin, sizeof(sin)) == -1) {perror("bind");return 1;}printf("服务器已启动\n");node_p clients = create_link();char rbuf[MESSAGE_SIZE];struct sockaddr_in cin;socklen_t addrlen = sizeof(cin);while (1) {bzero(rbuf, sizeof(rbuf));int n = recvfrom(sfd, rbuf, sizeof(rbuf), 0, (struct sockaddr*)&cin, &addrlen);rbuf[n] = '\0';if (strncmp(rbuf, "LOGIN:", 6) == 0) {char *username = rbuf + 6;insert(clients, username, cin);printf("用户 %s 登录, IP: %s, 端口: %d\n", username, inet_ntoa(cin.sin_addr), ntohs(cin.sin_port));char login_msg[MESSAGE_SIZE];snprintf(login_msg, sizeof(login_msg), "%s 已登录", username);broadcast_message(sfd, clients, login_msg, NULL);}else if (strncmp(rbuf, "MSG:", 4) == 0) {char *msg = rbuf + 4;char user_msg[MESSAGE_SIZE];snprintf(user_msg, sizeof(user_msg), "[%s]: %s", clients->name, msg);printf("用户 %s 发送了一条消息: %s\n", clients->name, msg);broadcast_message(sfd, clients, user_msg, &cin);}else if (strncmp(rbuf, "LOGOUT:", 7) == 0) {char *username = rbuf + 7;printf("用户 %s 下线, IP: %s, 端口: %d\n", username, inet_ntoa(cin.sin_addr), ntohs(cin.sin_port));remove_node(clients, cin);char logout_msg[MESSAGE_SIZE];snprintf(logout_msg, sizeof(logout_msg), "%s 已下线", username);broadcast_message(sfd, clients, logout_msg, NULL);}else if (strncmp(rbuf, "SYSMSG:", 7) == 0) {char *sys_msg = rbuf + 7;broadcast_message(sfd, clients, sys_msg, NULL);}}close(sfd);return 0;
}

客户端（未完成）

#include <header.h>
#define MESSAGE_SIZE 1024int main(int argc, char *argv[])
{if (argc != 3) {printf("请依次输入正确的服务器ip地址和端口号！\n");return 1;}char *server_ip = argv[1];int server_port = atoi(argv[2]);int cfd = socket(AF_INET, SOCK_DGRAM, 0);if (cfd == -1){perror("socket");return 1;}struct sockaddr_in sin;sin.sin_family = AF_INET;sin.sin_port = htons(server_port);sin.sin_addr.s_addr = inet_addr(server_ip);struct pollfd pfd[2];pfd[0].fd = 0;  pfd[0].events = POLLIN;pfd[1].fd = cfd;pfd[1].events = POLLIN;char wbuf[MESSAGE_SIZE] = {0};char rbuf[MESSAGE_SIZE] = {0};char username[20] = {0};printf("请输入用户名---> ");scanf("%s", username);getchar();char login_message[MESSAGE_SIZE];snprintf(login_message, sizeof(login_message), "LOGIN:%s", username);sendto(cfd, login_message, strlen(login_message), 0, (struct sockaddr*)&sin, sizeof(sin));while (1) {int res = poll(pfd, 2, -1);if (res == -1) {perror("poll");return 1;}if (pfd[0].revents == POLLIN){bzero(wbuf, sizeof(wbuf));fgets(wbuf, sizeof(wbuf), stdin);wbuf[strlen(wbuf) - 1] = '\0';  char message[MESSAGE_SIZE];snprintf(message, strlen("MSG:") + strlen(wbuf) + 1, "MSG:%s", wbuf);sendto(cfd, message, strlen(message), 0, (struct sockaddr*)&sin, sizeof(sin));printf("消息发送成功\n");}if (pfd[1].revents == POLLIN) {bzero(rbuf, sizeof(rbuf));recvfrom(cfd, rbuf, sizeof(rbuf), 0, NULL, NULL);if (strncmp(rbuf, "SYSMSG:", 7) == 0) {printf("%s\n", rbuf);}else{printf("收到的消息是: %s\n", rbuf);}}}close(cfd);return 0;
}