使用UDP套接字实现广播消息

此代码在ubuntu10.04系统上测试可正常使用。原来一直把发送地址填写成了多播地址，导致接收端可以抓到数据包但是程序无法接收到数据（多播程序写的太多，混淆了，哈哈）。

发送方代码如下：

#include
#include
#include
#include
#include
#include
#include
#include

#define N 64

//#define BROADCAST_ADDR "192.168.121.255" //注意应该填写广播地址

typedef struct sockaddr SA;

int main(int argc, char *argv[])
{
 int sockfd, on = 1;
 socklen_t addr_len;
 char buf[N];
 struct sockaddr_in peeraddr;

 if (argc < 3)
 {
  printf("input format is : %s    \n", argv[0]);
  return -1;
 }

 if ((sockfd = socket(PF_INET, SOCK_DGRAM, 0)) == -1)
 {
  perror("sock fail");
  return -1;
 }

 if (setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) == -1)
 {
  perror("setsockopt fail");
  exit(-1);
 }

 peeraddr.sin_family = PF_INET;
 peeraddr.sin_port = htons(atoi(argv[2]));
 peeraddr.sin_addr.s_addr = inet_addr(argv[1]);

 strcpy(buf, "Hi! I am broadcast messgae\n");
 while (1)
 {
  addr_len = sizeof(peeraddr);
  sendto(sockfd, buf, N, 0, (SA *)&peeraddr, addr_len);
  sleep(4);
 }

 return 0;
}

 

接收方代码如下：

#include
#include
#include
#include
#include
#include
#include

#define N 64

typedef struct sockaddr SA;

int main(int argc, char *argv[])
{
 int sockfd;
 socklen_t addr_len;
 char buf[N];
 struct sockaddr_in myaddr, peeraddr;

 if (argc < 2)
 {
  printf("input format is : %s  \n", argv[0]);
  return -1;
 }

 if ((sockfd = socket(PF_INET, SOCK_DGRAM, 0)) == -1)
 {
  perror("sock fail");
  return -1;
 }

 myaddr.sin_family = PF_INET;
 myaddr.sin_port = htons(atoi(argv[1]));
 myaddr.sin_addr.s_addr = INADDR_ANY;

 if (bind(sockfd, (SA *)&myaddr, sizeof(myaddr)) == -1)
 {
  perror("bind fail");
  return -1;
 }

 while (1)
 {
  addr_len = sizeof(peeraddr);
  recvfrom(sockfd, buf, N, 0, (SA *)&peeraddr, &addr_len);
  printf("recv from %s[%d]:%s\n", inet_ntoa(peeraddr.sin_addr),
          ntohs(peeraddr.sin_port), buf);
 }

 return 0;
}