一、概述
1、需求
使用TCP连接,1个server,多个client。server和多个client之间,可以互相发送消息。
二、分析
1、使用fork实现
2、基础知识参考TCP套接字编程
三、代码
1、服务端server.cpp
// #include <sys/types.h> #include <sys/socket.h> #include <stdio.h> #include <netinet/in.h> #include <arpa/inet.h> #include <unistd.h> #include <string.h> #include <stdlib.h> #include <fcntl.h> #include <sys/shm.h> #define PORT 8890 #define QUEUE_SIZE 10 #define BUFFER_SIZE 1024 //传进来的sockfd,就是互相建立好连接之后的socket文件描述符 //通过这个sockfd,可以完成 [服务端]<--->[客户端] 互相收发数据 void str_echo(int sockfd) { char buffer[BUFFER_SIZE]; pid_t pid = getpid(); while(1) { memset(buffer,0,sizeof(buffer)); int len = recv(sockfd, buffer, sizeof(buffer),0); if(strcmp(buffer,"exit\n")==0) { printf("child process: %d exited.\n",pid); break; } printf("pid:%d receive:\n",pid); fputs(buffer, stdout); send(sockfd, buffer, len, 0); } close(sockfd); } int main(int argc, char **argv) { //定义IPV4的TCP连接的套接字描述符 int server_sockfd = socket(AF_INET,SOCK_STREAM, 0); //定义sockaddr_in struct sockaddr_in server_sockaddr; server_sockaddr.sin_family = AF_INET; server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY); server_sockaddr.sin_port = htons(PORT); //bind成功返回0,出错返回-1 if(bind(server_sockfd,(struct sockaddr *)&server_sockaddr,sizeof(server_sockaddr))==-1) { perror("bind"); exit(1);//1为异常退出 } printf("bind success.\n"); //listen成功返回0,出错返回-1,允许同时帧听的连接数为QUEUE_SIZE if(listen(server_sockfd,QUEUE_SIZE) == -1) { perror("listen"); exit(1); } printf("listen success.\n"); for(;;) { struct sockaddr_in client_addr; socklen_t length = sizeof(client_addr); //进程阻塞在accept上,成功返回非负描述字,出错返回-1 int conn = accept(server_sockfd, (struct sockaddr*)&client_addr,&length); if(conn<0) { perror("connect"); exit(1); } printf("new client accepted.\n"); pid_t childid; if(childid=fork()==0)//子进程 { printf("child process: %d created.\n", getpid()); close(server_sockfd);//在子进程中关闭监听 str_echo(conn);//处理监听的连接 exit(0); } } printf("closed.\n"); close(server_sockfd); return 0; } //
2、客户端client.cpp
// #include <sys/types.h> #include <sys/socket.h> #include <stdio.h> #include <netinet/in.h> #include <arpa/inet.h> #include <unistd.h> #include <string.h> #include <stdlib.h> #include <fcntl.h> #include <sys/shm.h> #define PORT 8890 #define BUFFER_SIZE 1024 int main(int argc, char **argv) { if(argc!=2) { printf("usage: client IP \n"); exit(0); } //定义IPV4的TCP连接的套接字描述符 int sock_cli = socket(AF_INET,SOCK_STREAM, 0); //定义sockaddr_in struct sockaddr_in servaddr; memset(&servaddr, 0, sizeof(servaddr)); servaddr.sin_family = AF_INET; servaddr.sin_addr.s_addr = inet_addr(argv[1]); servaddr.sin_port = htons(PORT); //服务器端口 //连接服务器,成功返回0,错误返回-1 if (connect(sock_cli, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) { perror("connect"); exit(1); } printf("connect server(IP:%s).\n",argv[1]); char sendbuf[BUFFER_SIZE]; char recvbuf[BUFFER_SIZE]; //客户端将控制台输入的信息发送给服务器端,服务器原样返回信息 while (fgets(sendbuf, sizeof(sendbuf), stdin) != NULL) { send(sock_cli, sendbuf, strlen(sendbuf),0); ///发送 if(strcmp(sendbuf,"exit\n")==0) { printf("client exited.\n"); break; } printf("client receive:\n"); recv(sock_cli, recvbuf, sizeof(recvbuf),0); ///接收 fputs(recvbuf, stdout); memset(sendbuf, 0, sizeof(sendbuf)); memset(recvbuf, 0, sizeof(recvbuf)); } close(sock_cli); return 0; } //
3、编译
// g++ -o server_fork sever_fork.cpp g++ -o client client.cpp //
4、测试
(1)server
(2)client
致谢
2、TCP套接字编程