广播的发送程序

广播的发送程序如下：其程序流程非常简单，使用的是用户数据报协议，只要用函数setsockopt（）将其修改为发送广播其余的与编写UDP服务器差不多！

 

Send.c

 

 

#include<stdio.h>

#include<stdlib.h>

#include<sys/types.h>

#include<sys/socket.h>

#include<netinet/in.h>

#include<arpa/inet.h>

#include<string.h>

#include<fcntl.h>

#include<unistd.h>

 

typedef struct sockaddr ADDR;

 

 

int main(int argc, char *argv[])

{

    ssize_t n;

    char buf[] = "this isbroadcast packet";

    int serverfd,port ;

    struct sockaddr_inmyaddr,peeraddr;

    if(argc < 3)

    {

        printf("the usage :%s ipport",argv[0]);

        exit(-1);

    }

    if((serverfd =socket(PF_INET,SOCK_DGRAM,0)) < 0)

    {

        perror("fail tsocket");

        exit(-1);

    }

    port = atoi(argv[2]);

    myaddr.sin_family = PF_INET;

    myaddr.sin_port = htons(port);

    myaddr.sin_addr.s_addr =inet_addr(argv[1]);   

    int on = 1;

    setsockopt(serverfd,SOL_SOCKET,SO_BROADCAST,&on,sizeof(on));

 

 

        socklen_t peerlen =sizeof(peeraddr);

    while(1)

    {

        sendto(serverfd,buf,sizeof(buf),0,(ADDR*)&myaddr,sizeof(myaddr));

        sleep(1);

    }

    return 0;

}

 

 

 

 

receive.c

 

 

 

#include<stdio.h>

#include<stdlib.h>

#include<sys/types.h>

#include<sys/socket.h>

#include<netinet/in.h>

#include<arpa/inet.h>

#include<string.h>

#include<fcntl.h>

#include<unistd.h>

 

typedef struct sockaddr ADDR;

 

 

int main(int argc, char *argv[])

{

    ssize_t n;

    char buf[256];

    int serverfd,port ;

    struct sockaddr_inmyaddr,peeraddr;

    if(argc < 3)

    {

        printf("the usage :%s ipport",argv[0]);

        exit(-1);

    }

    if((serverfd =socket(PF_INET,SOCK_DGRAM,0)) < 0)

    {

        perror("fail tsocket");

        exit(-1);

    }

    port = atoi(argv[2]);

    myaddr.sin_family = PF_INET;

    myaddr.sin_port = htons(port);

    myaddr.sin_addr.s_addr =inet_addr(argv[1]);   

   

    if(bind(serverfd,(ADDR*)&myaddr ,sizeof(myaddr)) < 0)

    {

        perror("failto  bind");

        exit(-1);

    }

    socklen_t peerlen =sizeof(peeraddr);

    while(1)

    {

        recvfrom(serverfd,buf,256,0,(ADDR*)&peeraddr,&peerlen);

        printf("[%s %d]%s\n",inet_ntoa(peeraddr.sin_addr),ntohs(peeraddr.sin_port),buf);

    }

       

 

 

 

    return 0;

}