#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <errno.h>

#include <netdb.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <sys/types.h>

#include <sys/wait.h>

typedef struct sockaddr SA;

int open_clientfd(char* hostname,int port)

{

    int clientfd;

    struct hostent * hp;

    struct sockaddr_in serveraddr;

    char* msg;

    /*创建socket*/

    if((clientfd=socket(AF_INET,SOCK_STREAM,))<)

    {

        msg="client socket() error!\n";

        write(STDOUT_FILENO,msg,strlen(msg));

        return -;

    }

    msg="client socket() success!\n";

    write(STDOUT_FILENO,msg,strlen(msg));

    /*填写server的ip地址和port*/

    if((hp=gethostbyname(hostname))==NULL)

    {

        msg="client gethostbyname() error!\n";

        write(STDOUT_FILENO,msg,strlen(msg));

        return -;

    }

    msg="client gethostbyname() success!\n";

    write(STDOUT_FILENO,msg,strlen(msg));

    bzero((char*)&serveraddr,sizeof(serveraddr));

    serveraddr.sin_family=AF_INET;

    serveraddr.sin_port=htons(port);

    bcopy((char*)hp->h_addr_list[],(char*)&serveraddr.sin_addr.s_addr,hp->h_length);

    /*建立连接*/

    if(connect(clientfd,(SA*)&serveraddr,sizeof(serveraddr))<)

    {

        msg="client connect() error!\n";

        write(STDOUT_FILENO,msg,strlen(msg));

        return -;

    }

    msg="client connect() success!\n";

    write(STDOUT_FILENO,msg,strlen(msg));

    return clientfd;

}

int open_listenfd(int port)

{

    int listenfd,optval;

    struct sockaddr_in serveraddr;

    char* msg;

    /*创建socket*/

    if((listenfd=socket(AF_INET,SOCK_STREAM,))<)

    {

        msg="server socket() error!\n";

        write(STDOUT_FILENO,msg,strlen(msg));

        return -;

    }

    msg="server socket() success!\n";

    write(STDOUT_FILENO,msg,strlen(msg));

    /*配置服务器使得它能被立即终止和重启*/

    if(setsockopt(listenfd,SOL_SOCKET,SO_REUSEADDR,(const void *)&optval,sizeof(int))<)

    {

        msg="server setsockopt() error!\n";

        write(STDOUT_FILENO,msg,strlen(msg));

        return -;

    }

    msg="server setsockopt() success!\n";

    write(STDOUT_FILENO,msg,strlen(msg));

    /*绑定服务端的ip和端口*/

    bzero((char*)&serveraddr,sizeof(serveraddr));

    serveraddr.sin_family=AF_INET;

    serveraddr.sin_port=htons((unsigned short)port);

    serveraddr.sin_addr.s_addr=htonl(INADDR_ANY);

    if(bind(listenfd,(SA*)&serveraddr,sizeof(serveraddr))<)

    {

        msg="server bind() error!\n";

        write(STDOUT_FILENO,msg,strlen(msg));

        return -;

    }

    msg="server bind() success!\n";

    write(STDOUT_FILENO,msg,strlen(msg));

    /*创建listen*/

    if(listen(listenfd,)<)

    {

        msg="server listen() error!\n";

        write(STDOUT_FILENO,msg,strlen(msg));

        return -;

    }

    msg="server listen() success!\n";

    write(STDOUT_FILENO,msg,strlen(msg));

    return listenfd;

}