广播组播的代码

一、广播
1.接收

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>

#define IP "192.168.138.255"    //服务器 IP
#define PORT 8888            //端口号
#define MAX 128

#define ERROR(msg) do{\
	fprintf(stderr, "__%d__", __LINE__);\
	perror(msg);\
}while(0)

int main(int argc, char *argv[])
{
	int sfd;
	char buf[MAX] = "";
	struct sockaddr_in server_addr;

	//1.创建流式套接字
	sfd = socket(AF_INET, SOCK_DGRAM, 0);
	if (sfd == -1)
	{
		ERROR("socket");
		return -1;
	}

	//填充地址信息结构体
	memset(&server_addr, 0, sizeof(struct sockaddr_in));
	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(PORT);   //端口的网络字节序
	server_addr.sin_addr.s_addr = inet_addr(IP);  //IP的网络字节序
	
	//允许端口快速被重用
	int reuse = 1;
	if(setsockopt(sfd, SOL_SOCKET, SO_BROADCAST, &reuse ,sizeof(reuse)) < 0)
	{
		ERROR("setsockopt");
		return -1;
	}

	//2.将地址信息绑定到套接字上
	if (bind(sfd, (struct sockaddr *) &server_addr,
				sizeof(struct sockaddr_in)) == -1)
	{
		ERROR("bind");
		return -1;
	}
	
	ssize_t res;
	while(1)
	{
		bzero(buf, sizeof(buf));
		//接收信息
		res = recvfrom(sfd, buf, sizeof(buf), 0, NULL,0);
		if(res < 0)
		{
			ERROR("recvfrom");
			return -1;
		}
		printf(":%s\n", buf);
	}

	close(sfd);

	return 0;
}

2.发送

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>

#define SERVER_IP "192.168.138.255" //服务器 IP
#define SERVER_PORT 8888             //服务器端口号
#define MAX 128

#define ERROR(msg) do{\
	fprintf(stderr, "__%d__", __LINE__);\
	perror(msg);\
}while(0)

int main(int argc, char *argv[])
{
	int cfd,sfd;
	struct sockaddr_in server_addr;
	socklen_t server_addr_size;

	//1.创建数据报式套接字
	cfd = socket(AF_INET, SOCK_DGRAM, 0);
	if (cfd == -1)
	{
		ERROR("socket");
		return -1;
	}

	//2.允许广播
	int on=1;
    if(setsockopt(cfd,SOL_SOCKET,SO_REUSEADDR | SO_BROADCAST,&on,sizeof(on)) < 0)
	{
		ERROR("setsockopt");
		return -1;
	}

	//3.填充服务器地址信息结构体
	memset(&server_addr, 0, sizeof(struct sockaddr_in));
	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(SERVER_PORT);   //端口的网络字节序
	server_addr.sin_addr.s_addr = inet_addr(SERVER_IP);  //IP的网络字节序

	char buf[MAX] = "";
	ssize_t res = 0;
	server_addr_size = sizeof(struct sockaddr_in);

	while(1)
	{
		bzero(buf, sizeof(buf));
		fgets(buf, sizeof(buf), stdin);
		buf[strlen(buf)-1] = '\0';
		//5.发送信息
		if(sendto(cfd, buf, sizeof(buf), 0, (struct sockaddr*)&server_addr, server_addr_size) < 0)
		{
			ERROR("sendto");
			return -1;
		}
	}

}

二、组播
1.接收

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <unistd.h>
#include <string.h>

#define IP "224.255.255.255"    //组 IP

#define PORT 8888            //端口号
#define LOC_IP "192.168.138.101"
#define MAX 128

#define ERROR(msg) do{\
	fprintf(stderr, "__%d__", __LINE__);\
	perror(msg);\
}while(0)

int main(int argc, char *argv[])
{
	int sfd;
	char buf[MAX] = "";
	struct sockaddr_in rec_addr;

	//1.创建流式套接字
	sfd = socket(AF_INET, SOCK_DGRAM, 0);
	if (sfd == -1)
	{
		ERROR("socket");
		return -1;
	}

	
	//加入多播组
	struct ip_mreqn ip_addr;
	ip_addr.imr_multiaddr.s_addr = inet_addr(IP); 	//组播IP
	ip_addr.imr_address.s_addr = inet_addr(LOC_IP); //本机IP
	ip_addr.imr_ifindex = 2; 		//设备索引号
	socklen_t size = sizeof(ip_addr);
	if(setsockopt(sfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &ip_addr,size) < 0)
	{
		ERROR("setsockopt");
		return -1;
	}

	//填充地址信息结构体
	memset(&rec_addr, 0, sizeof(struct sockaddr_in));
	rec_addr.sin_family = AF_INET;
	rec_addr.sin_port = htons(PORT);   //端口的网络字节序
	rec_addr.sin_addr.s_addr = inet_addr(IP);  //IP的网络字节序
	
	//2.将地址信息绑定到套接字上
	if (bind(sfd, (struct sockaddr *) &rec_addr,
				sizeof(struct sockaddr_in)) == -1)
	{
		ERROR("bind");
		return -1;
	}
	
	ssize_t res;
	while(1)
	{
		bzero(buf, sizeof(buf));
		//接收信息
		res = recvfrom(sfd, buf, sizeof(buf), 0, NULL,0);
		if(res < 0)
		{
			ERROR("recvfrom");
			return -1;
		}
		printf(":%s\n", buf);
	}

	close(sfd);

	return 0;
}

2.发送

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>

#define IP "224.255.255.255" //组ip
#define PORT 8888             //服务器端口号
#define MAX 128

#define ERROR(msg) do{\
	fprintf(stderr, "__%d__", __LINE__);\
	perror(msg);\
}while(0)

int main(int argc, char *argv[])
{
	int sfd;
	struct sockaddr_in send_addr;
	socklen_t send_addr_size;

	//1.创建数据报式套接字
	sfd = socket(AF_INET, SOCK_DGRAM, 0);
	if (sfd == -1)
	{
		ERROR("socket");
		return -1;
	}

	//2.填充组播地址信息结构体
	memset(&send_addr, 0, sizeof(struct sockaddr_in));
	send_addr.sin_family = AF_INET;
	send_addr.sin_port = htons(PORT);   //端口的网络字节序
	send_addr.sin_addr.s_addr = inet_addr(IP);  //IP的网络字节序

	char buf[MAX] = "";
	ssize_t res = 0;
	send_addr_size = sizeof(struct sockaddr_in);

	while(1)
	{
		bzero(buf, sizeof(buf));
		fgets(buf, sizeof(buf), stdin);
		buf[strlen(buf)-1] = '\0';
		//5.发送信息
		if(sendto(sfd, buf, sizeof(buf), 0, (struct sockaddr*)&send_addr, send_addr_size) < 0)
		{
			ERROR("sendto");
			return -1;
		}
	}
	close(sfd);
}