linux网络编程实现,【网络编程】Linux多播简单实现

在测试多时先确定测试的接口(网卡)是否已经开启多播功能，如下：

图.1

其中RUNNING MULTICAST表示开启了多播功能,可用ifconfig命令开启

多播数据发送端：

#include

#include

#include

#include

#include

#include

#include

#include

#include

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

{

if (argc != 3)

{

printf("Usage:./exec [multicast_ip] [port]n");

exit(-1);

}

struct sockaddr_in servsend;

socklen_t len = sizeof(struct sockaddr_in);

int ret;

int sendfd = socket(AF_INET, SOCK_DGRAM, 0);

/* 目的地址为多播地址 */

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

servsend.sin_port = htons(atoi(argv[2]));

servsend.sin_family = AF_INET;

u_char off = 1;

/*开启外出数据包的回馈*/

setsockopt(sendfd, IPPROTO_IP, IP_MULTICAST_LOOP, &off, sizeof(off));

/* 选择多播外出接口 */

char buf[256];

struct in_addr in;

in.s_addr = inet_addr("192.168.1.115");

setsockopt(sendfd, IPPROTO_IP, IP_MULTICAST_IF, &in, sizeof(in));

while (1)

{

sprintf(buf, "I am random [%d]", (int)random()%100);

ret = sendto(sendfd, buf, strlen(buf), 0, (struct sockaddr *)&servsend, len);

if (ret < 0)

{

printf("sendto errorn");

exit(-1);

}

sleep(2);

}

return 0;

}

多播数据接受端：

#include

#include

#include

#include

#include

#include

#include

#include

#include

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

{

if (argc != 3)

{

printf("Usage:./exec [multicast_ip] [port]n");

exit(-1);

}

int ret;

struct sockaddr_in servrecv;

int len = sizeof(servrecv);

int recvfd = socket(AF_INET, SOCK_DGRAM, 0);

const int on = 1;

ret = setsockopt(recvfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));

if (ret < 0)

{

printf("setsockopt errorn");

exit(-1);

}

servrecv.sin_port = htons(atoi(argv[2]));

servrecv.sin_addr.s_addr = htonl(INADDR_ANY);

servrecv.sin_family = AF_INET;

ret = bind(recvfd, (struct sockaddr *)&servrecv, len);

if (ret < 0)

{

printf("bind errorn");

exit(-1);

}

/* 加入多播组 */

struct ip_mreq mreq;

mreq.imr_multiaddr.s_addr = inet_addr(argv[1]);

mreq.imr_interface.s_addr = inet_addr("192.168.1.115");

ret = setsockopt(recvfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq));

if (ret < 0)

{

printf("setsockopt error(2)n");

exit(-1);

}

struct sockaddr_in in;

while (1)

{

char buf[256];

memset(buf, 0, 256);

len = sizeof(in);

ret = recvfrom(recvfd, buf, 256, 0, (struct sockaddr *)&in, &len);

if (ret < 0)

{

printf("recvfrom errorn");

exit(-1);

}

printf("%sn", buf);

}

return 0;

}