广播:顾名思义可以把自己的数据发送给在特定范围内的所有人;我们网络编程中的广播一般是通过特定的广播地址把自己的数据发送给局域网内当前在线的客户端
我们可以使用命令查看我们Linux下当前的广播地址:ifconfig
我们只需要往这个广播地址发送数据,当前局域网内的其他在线客户端就可以收到这个信息了
代码:
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
int broadcast_send(int port)
{
int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
if(sockfd < 0)
{
perror("socket error");
return -1;
}
int on=1;
int ret = setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on));
if(ret < 0)
{
perror("setsockopt error");
goto err;
}
char buffer[]="hello world";
struct sockaddr_in dest_addr;
memset(&dest_addr, 0, sizeof(dest_addr));
dest_addr.sin_family = AF_INET;
dest_addr.sin_port = htons(port);
dest_addr.sin_addr.s_addr = inet_addr("192.168.19.255");
ret = sendto(sockfd, buffer, sizeof(buffer), 0, (struct sockaddr*)&dest_addr, sizeof(dest_addr));
if(ret < 0)
{
perror("sendto error");
goto err;
}
err:
close(sockfd);
return 0;
}
int broadcast_recv(int port)
{
int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
if(sockfd < 0)
{
perror("socket error");
return -1;
}
int on=1;
int rt = setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
if(rt < 0)
{
perror("setsockopt error");
goto recverr;
}
struct sockaddr_in src_addr;
memset(&src_addr, 0, sizeof(src_addr));
src_addr.sin_family = AF_INET;
src_addr.sin_port = htons(port);
src_addr.sin_addr.s_addr = htonl(INADDR_ANY);
int ret = bind(sockfd, (struct sockaddr*)&src_addr, sizeof(src_addr));
if(ret < 0)
{
perror("bind error");
goto recverr;
}
char buffer[128]={0};
struct sockaddr_in sendaddr;
socklen_t len = sizeof(sendaddr);
ret = recvfrom(sockfd, buffer, sizeof(buffer), 0, (struct sockaddr*)&sendaddr, &len);
if(ret < 0)
{
perror("recvfrom error");
goto recverr;
}
printf("接到数据:%s\n", buffer);
recverr:
close(sockfd);
return 0;
}
int main(int argc, char **argv)
{
if(argc >= 2 && strcmp(argv[1],"send")==0)
broadcast_send(9999);
if(argc >= 2 && strcmp(argv[1],"recv")==0)
broadcast_recv(9999);
return 0;
}
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