Linux下TCP网络服务器与客户端通信程序入门

目标

实现客户端连接服务器，通过终端窗口发送信息给服务器端，服务器接收到信息后对信息数据进行回传，客户端读取回传信息并返回。

服务器与客户端通信流程

TCP服务器代码

服务器当前IP地址要知道
建立socket
绑定本地IP地址并设置端口号

#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>int main()
{//socket套接字int lfd = socket(AF_INET, SOCK_STREAM, 0);if(lfd == -1){perror("socket");exit(-1);}//绑定struct sockaddr_in saddr;saddr.sin_family = AF_INET;inet_pton(AF_INET, "192.168.1.108", &saddr.sin_addr.s_addr);//saddr.sin_addr.s_addr = INADDR_ANY;//做服务器时表示可以通过任意网卡都可以连接进来saddr.sin_port = htons(9999);//转换成网络字节序int bindret = bind(lfd, (struct sockaddr *)&saddr, sizeof(saddr));if(bindret == -1){perror("bind");exit(-1);}//监听int ret = listen(lfd, 8);if(ret == -1){perror("listen");exit(-1);}//等待连接struct sockaddr_in clientaddr;int len = sizeof(clientaddr);int cfd = accept(lfd, (struct sockaddr *)&clientaddr, &len);if(cfd == -1){perror("accept");exit(-1);}char clientIP[len];inet_ntop(AF_INET, &clientaddr.sin_addr, clientIP, len);printf("client IP:%s Port:%d\n", clientIP, ntohs(clientaddr.sin_port));while (1){//接收数据char rbuf[1024];len = read(cfd, rbuf, sizeof(rbuf));if(len == -1){perror("read");exit(-1);}else if(len == 0){printf("Client close...\n");}else if(len > 0){printf("resive data: %s\n", rbuf);}//发送数据char sbuf[] = "i am server\n";write(cfd, rbuf, sizeof(rbuf));}//关闭连接close(cfd);close(lfd);return 0;
}

TCP客户端代码

知道服务器的IP地址和端口号
然后进行连接

#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>int main()
{//socket套接字int lfd = socket(AF_INET, SOCK_STREAM, 0);if(lfd == -1){perror("socket");exit(-1);}//连接struct sockaddr_in saddr;saddr.sin_family = AF_INET;inet_pton(AF_INET, "192.168.1.108", &saddr.sin_addr.s_addr);saddr.sin_port = htons(9999);//转换成网络字节序int connect_cont = 3;int ret;jx_connect:ret = connect(lfd, (struct sockaddr *)&saddr, sizeof(saddr));if(ret == -1){perror("connect");sleep(2);connect_cont--;if(connect_cont) goto jx_connect;exit(-1);}printf("client link success!\n");//通信char rbuf[1024];while(1){//发送数据char sbuf[] = "i am client\n";fgets(rbuf, 1024, stdin);write(lfd, rbuf, sizeof(rbuf));//接收数据int len = read(lfd, rbuf, sizeof(rbuf));if(len == -1){perror("read");exit(-1);}else if(len == 0){printf("Client close...\n");break;}else if(len > 0){printf("resive data: %s\n", rbuf);}sleep(1);}//关闭连接close(lfd);return 0;
}