BSDSocket编程之UDP

原文地址：http://www.1000phone.net/thread-7783-1-5.html

 

UDPClient

/*UDP/IP应用编程接口（API）*//**客户端的工作流程：首先调用socket函数创建一个Socket，填写服务器地址及端口号，*从标准输入设备中取得字符串，将字符串传送给服务器端，并接收服务器端返回的字*符串。最后关闭该socket。*/#include<stdio.h>#include<stdlib.h>#include<string.h>#include<errno.h>#include<sys/types.h>#include<sys/socket.h>#include<netinet/in.h>int GetServerAddr(char * addrname){    printf("please input server addr:");    scanf("%s",addrname);    return 1;}int main(int argc,char **argv){    int cli_sockfd;    int len;    socklen_t addrlen;    char seraddr[14];    struct sockaddr_in cli_addr;    char buffer[256];    GetServerAddr(seraddr);    /* 建立socket*/    cli_sockfd=socket(AF_INET,SOCK_DGRAM,0);    if(cli_sockfd<0)    {        printf("I cannot socket success\n");        return 1;    }    /* 填写sockaddr_in*/    addrlen=sizeof(struct sockaddr_in);    bzero(&cli_addr,addrlen);    cli_addr.sin_family=AF_INET;    cli_addr.sin_addr.s_addr=inet_addr(seraddr);    //cli_addr.sin_addr.s_addr=htonl(INADDR_ANY);    cli_addr.sin_port=htons(SERVER_PORT);    bzero(buffer,sizeof(buffer));    /* 从标准输入设备取得字符串*/    len=read(STDIN_FILENO,buffer,sizeof(buffer));    /* 将字符串传送给server端*/    sendto(cli_sockfd,buffer,len,0,(struct sockaddr*)&cli_addr,addrlen);    /* 接收server端返回的字符串*/    len=recvfrom(cli_sockfd,buffer,sizeof(buffer),0,(struct sockaddr*)&cli_addr,&addrlen);    //printf("receive from %s\n",inet_ntoa(cli_addr.sin_addr));    printf("receive: %s",buffer);    close(cli_sockfd);}

UDPServer

/*UDP/IP应用编程接口（API）*//**服务器的工作流程：首先调用socket函数创建一个Socket，然后调用bind函数将其与本机*地址以及一个本地端口号绑定，接收到一个客户端时，服务器显示该客户端的IP地址，并将字串*返回给客户端。*/#include<stdio.h>#include<stdlib.h>#include<string.h>#include<errno.h>#include<sys/types.h>#include<sys/socket.h>#include<netinet/in.h>int main(int argc,char **argv){    int ser_sockfd;    int len;    //int addrlen;    socklen_t addrlen;    char seraddr[100];    struct sockaddr_in ser_addr;            /*建立socket*/    ser_sockfd=socket(AF_INET,SOCK_DGRAM,0);    if(ser_sockfd<0)    {        printf("I cannot socket success\n");        return 1;    }            /*填写sockaddr_in 结构*/    addrlen=sizeof(struct sockaddr_in);    bzero(&ser_addr,addrlen);    ser_addr.sin_family=AF_INET;    ser_addr.sin_addr.s_addr=htonl(INADDR_ANY);    ser_addr.sin_port=htons(SERVER_PORT);    /*绑定客户端*/    if(bind(ser_sockfd,(struct sockaddr *)&ser_addr,addrlen)<0)    {        printf("connect");        return 1;    }    while(1)    {        bzero(seraddr,sizeof(seraddr));        len=recvfrom(ser_sockfd,seraddr,sizeof(seraddr),0,(struct sockaddr*)&ser_addr,&addrlen);        /*显示client端的网络地址*/        printf("receive from %s\n",inet_ntoa(ser_addr.sin_addr));        /*显示客户端发来的字串*/         printf("recevce:%s",seraddr);        /*将字串返回给client端*/        sendto(ser_sockfd,seraddr,len,0,(struct sockaddr*)&ser_addr,addrlen);    }}