.NET2005/关于UDP广播

发布网友发布时间：2022-05-23 14:58

共1个回答

热心网友时间：2023-09-09 21:24

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<netinet/in.h>
#include<sys/types.h>
#include<netdb.h>

#define PORT 51654

int main(int argc,char* argv[])
{
int sockfd;
struct sockaddr_in their_addr;
struct in_addr addr;
struct hostent *he;
int broadcast = 1;
int num = 0;

if(argc != 3)
{
fprintf(stderr,"Usage: broadcase hostname message\n");
exit(1);
}

if( inet_aton(argv[1],&addr) == 0)
{
he = gethostbyname(argv[1]); //Domain
addr.s_addr = (*(unsigned int *)*he->h_addr_list[0]);
}

if( (sockfd = socket(AF_INET,SOCK_DGRAM,0)) == -1 )
{
perror("socket function!\n");
exit(1);
}

if( setsockopt(sockfd,SOL_SOCKET,SO_BROADCAST,&broadcast,sizeof(broadcast)) == -1)
{
perror("setsockopt function!\n");
exit(1);
}

their_addr.sin_family = AF_INET;
their_addr.sin_port = htons(PORT);
their_addr.sin_addr = addr;

if( (num = sendto( sockfd,argv[2],strlen(argv[2]),0,(struct sockaddr *)&their_addr,sizeof(struct sockaddr) )) == -1)
{
perror("sendto function!\n");
exit(1);
}

printf("Send %d bytes to %s\n",num,inet_ntoa(their_addr.sin_addr) );

close(sockfd);

return 0;
}