---

4.15 TCP通信实现（服务器端）

// TCP 通信的服务器端// TCP 通信的服务器端
#include <stdio.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>int main(){//1、创建socket（用于监听）int lfd = socket(AF_INET,SOCK_STREAM,0);if(lfd == -1){perror("socket");exit(0);}//2、绑定struct sockaddr_in saddr;saddr.sin_family = AF_INET; //协议族//把点分十进制IP地址转换成int 而且是网络字节序的//saddr->sin_addr.s_addr 本质是一个长整型的变量  结构体套结构体//第三个参数是传出参数，也就是转换好的void* 直接就给了saddr->sin_addr.s_addrinet_pton(AF_INET,"192.168.65.129",&saddr.sin_addr.s_addr); //p:point 点分十进制/*saddr->sin_addr.s_addr = 0; saddr->sin_addr.s_addr = INADDR_ANY;  INADDR_ANY这个宏就是00.0.0.0  表示任意地址 比如一台主机有两个网卡，两个都绑定客户端无论用哪一个IP地址 都可以访问到这台主机*///saddr->sin_port = 9999; 这是主机字节序的9999 要转成网络字节序saddr.sin_port = htons(9999);int ret = bind(lfd,(struct sockaddr*)&saddr,sizeof(saddr));if(ret == -1){perror("bind");exit(0);}//3、监听ret = listen(lfd,8);if(ret == -1){perror("listen");exit(0);}//4、接收客户端连接struct sockaddr_in clientaddr;socklen_t len = sizeof(clientaddr);int cfd = accept(lfd,(struct sockaddr*)&clientaddr,&len);if(cfd == -1){perror("accept");exit(0);}//打印客户端信息//把获取到的网络字节序IP和端口转换成主机字节序char clientIp[16];inet_ntop(AF_INET,&clientaddr.sin_addr.s_addr,clientIp,sizeof(clientIp));unsigned short clientPort = ntohs(clientaddr.sin_port);printf("client IP is: %s, port is %d: \n",clientIp,clientPort);//5、通信//获取客户端数据char recvBuf[1024] = {0};len = read(cfd,recvBuf,sizeof(recvBuf));if(len == -1){perror("accept");exit(0);}else if(len > 0){printf("recv client data = %s\n",recvBuf);}else if(len == 0){//表示客户端关闭连接printf("client close...");}//给客户端发送数据char* data = "hello,i am server";write(cfd,data,strlen(data));//6、关闭文件描述符close(cfd);close(lfd);return 0;
}

4.16 TCP通信实现（客户端）

// TCP 通信的服务器端
#include <stdio.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>int main(){//1、创建socket（用于监听）int lfd = socket(AF_INET,SOCK_STREAM,0);if(lfd == -1){perror("socket");exit(0);}//2、绑定struct sockaddr_in saddr;saddr.sin_family = AF_INET; //协议族//把点分十进制IP地址转换成int 而且是网络字节序的//saddr->sin_addr.s_addr 本质是一个长整型的变量  结构体套结构体//第三个参数是传出参数，也就是转换好的void* 直接就给了saddr->sin_addr.s_addrinet_pton(AF_INET,"192.168.65.129",&saddr.sin_addr.s_addr); //p:point 点分十进制/*saddr->sin_addr.s_addr = 0; saddr->sin_addr.s_addr = INADDR_ANY;  INADDR_ANY这个宏就是00.0.0.0  表示任意地址 比如一台主机有两个网卡，两个都绑定客户端无论用哪一个IP地址 都可以访问到这台主机*///saddr->sin_port = 9999; 这是主机字节序的9999 要转成网络字节序saddr.sin_port = htons(9999);int ret = bind(lfd,(struct sockaddr*)&saddr,sizeof(saddr));if(ret == -1){perror("bind");exit(0);}//3、监听ret = listen(lfd,8);if(ret == -1){perror("listen");exit(0);}//4、接收客户端连接struct sockaddr_in clientaddr;socklen_t len = sizeof(clientaddr);int cfd = accept(lfd,(struct sockaddr*)&clientaddr,&len);if(cfd == -1){perror("accept");exit(0);}//打印客户端信息//把获取到的网络字节序IP和端口转换成主机字节序char clientIp[16];inet_ntop(AF_INET,&clientaddr.sin_addr.s_addr,clientIp,sizeof(clientIp));unsigned short clientPort = ntohs(clientaddr.sin_port);printf("client IP is: %s, port is %d: \n",clientIp,clientPort);//5、通信//获取客户端数据char recvBuf[1024] = {0};len = read(cfd,recvBuf,sizeof(recvBuf));if(len == -1){perror("accept");exit(0);}else if(len > 0){printf("recv client data = %s\n",recvBuf);}else if(len == 0){//表示客户端关闭连接printf("client close...");}//给客户端发送数据char* data = "hello,i am server";write(cfd,data,strlen(data));//6、关闭文件描述符close(cfd);close(lfd);return 0;
}