Socket TCP 编程

服务器端：

#include <stdlib.h>#include <stdio.h>#include <errno.h>#include <string.h>#include <netdb.h>#include <sys/types.h>#include <netinet/in.h>#include <sys/socket.h>#define portnumber 3333int main(){ int sockfd,new_fd; struct sockaddr_in server_addr; struct sockaddr_in client_addr; int sin_size; int nbytes; char buffer[1024]; /*服务器端开始建立socket描述符*/if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1)  {     fprintf(stderr,"Socket error:%s \n\a",strerror(errno));    exit(1);  }  /*服务器端填充 socketaddr结构*/  bzero(&server_addr,sizeof(struct sockaddr_in));//初始化，置0  server_addr.sin_family=AF_INET;  server_addr.sin_addr.s_addr=htonl(INADDR_ANY);//将本机上的long数据转换为网络上的long，INADDR_ANY 表示主机可以是任意IP  //server_addr.sin_addr.s_addr=inet_addr("192.168.1.1");//用于绑定固定IP  server_addr.sin_port=htons(portnumber);//端口号，将本机上的short数据转化为网络上的short数据  /*绑定sockfd 到IP地址*/ if(bind(sockfd,(struct sockaddr*)(&server_addr),sizeof(struct sockaddr))==-1)   {    fprintf(stderr,"Bind error:%s \n\a",strerror(errno));    exit(1);  }  /*设置允许连接的最大客户端数*/ if(listen(sockfd,5)==-1) {   fprintf(stderr,"Listen error:%s \n\a",strerror(errno));   exit(1);  }   while(1)  {    /*服务器阻塞，直到客户程序建立连接*/    sin_size=sizeof(struct sockaddr_in);    if((new_fd=accept(sockfd,(struct sockaddr*)(&client_addr),&sin_size))==-1)     {      fprintf(stderr,"Accept error:%s \n\a",strerror(errno));      exit(1);    }    fprintf(stderr,"Server get connection from %s \n",inet_ntoa(client_addr.sin_addr));//将网络地址转化成.字符串     if((nbytes=read(new_fd,buffer,1024))==-1)  {    fprintf(stderr,"Read error :%s \n",strerror(errno));    exit(1);   }  buffer[nbytes]='\0';  printf("Server received %s \n ",buffer);    close(new_fd);  }   close(sockfd);   exit(0);}

客户端：

#include <stdlib.h>#include <stdio.h>#include <errno.h>#include <string.h>#include <netdb.h>#include <sys/types.h>#include <netinet/in.h>#include <sys/socket.h>#define portnumber 3333int main(int argc,char *argv[]){ int sockfd; struct sockaddr_in server_addr; struct hostent *host; char buffer[1024];if(argc!=2){  fprintf(stderr,"Usage:%s hostname \a\n",argv[0]);  exit(1);}/*使用hostname查询host名字*/ if((host=gethostbyname(argv[1]))==NULL) {   fprintf(stderr,"Get the host name error\n");   exit(1); } /*客户端开始建立socket描述符*/if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1)  {     fprintf(stderr,"Socket error:%s \n\a",strerror(errno));    exit(1);  }  /*客户段端填充 socketaddr结构*/  memset(&server_addr,0,sizeof(server_addr));//初始化，置0  server_addr.sin_family=AF_INET;//IPV4    server_addr.sin_port=htons(portnumber);//端口号，将本机上的short数据转化为网络上的short数据  server_addr.sin_addr=*((struct in_addr *)host->h_addr);//??主机的第一个IP地址 /*客户程序发起连接请求*/   if(connect(sockfd,(struct sockaddr *)(&server_addr),sizeof(struct sockaddr))==-1)  {     fprintf(stderr,"Connect Error:%s\n",strerror(errno));     exit(1);  }  /*连接成功*/  printf("Please input char :\n");  /*发送数据v*/ fgets(buffer,1024,stdin); write(sockfd,buffer,sizeof(buffer)); /*结束通讯*/   close(sockfd);   exit(0);}

运行客户端：

qust@qust-K42JZ:~/test$ gcc tcp_client.c -o tcp_client
qust@qust-K42JZ:~/test$ ./tcp_client 211.87.147.61
Please input char :
ddd

服务器端：

Server get connection from 211.87.147.61
 Server received ddd