Броадкаст сообщения UDP

Лови. С #include'ами, надеюсь, сам разберёшься.

ДВ

Sender Program /* * sender.c -- multicasts "hello, world!" to a multicast group once a second * * Antony Courtney, 25/11/94 */

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

#define HELLO_PORT 12345 #define HELLO_GROUP "225.0.0.37"

main(int argc, char *argv[]) { struct sockaddr_in addr; int fd, cnt; struct ip_mreq mreq; char *message="Hello, World!";

/* create what looks like an ordinary UDP socket */ if ((fd=socket(AF_INET,SOCK_DGRAM,0)) < 0) { perror("socket"); exit(1); }

/* set up destination address */ memset(&addr,0,sizeof(addr)); addr.sin_family=AF_INET; addr.sin_addr.s_addr=inet_addr(HELLO_GROUP); addr.sin_port=htons(HELLO_PORT);

/* now just sendto() our destination! */ while (1) { if (sendto(fd,message,sizeof(message),0,(struct sockaddr *) &addr, sizeof(addr)) < 0) { perror("sendto"); exit(1); } sleep(1); } }

--------------------------------------------------------------------------------

Listener Program /* * listener.c -- joins a multicast group and echoes all data it receives from * the group to its stdout... * * Antony Courtney, 25/11/94 */

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

#define HELLO_PORT 12345 #define HELLO_GROUP "225.0.0.37" #define MSGBUFSIZE 256

main(int argc, char *argv[]) { struct sockaddr_in addr; int fd, nbytes,addrlen; struct ip_mreq mreq; char msgbuf[MSGBUFSIZE];

/* create what looks like an ordinary UDP socket */ if ((fd=socket(AF_INET,SOCK_DGRAM,0)) < 0) { perror("socket"); exit(1); }

/* set up destination address */ memset(&addr,0,sizeof(addr)); addr.sin_family=AF_INET; addr.sin_addr.s_addr=htonl(INADDR_ANY); /* N.B.: differs from sender */ addr.sin_port=htons(HELLO_PORT);

/* bind to receive address */ if (bind(fd,(struct sockaddr *) &addr,sizeof(addr)) < 0) { perror("bind"); exit(1); }

/* use setsockopt() to request that the kernel join a multicast group */ mreq.imr_multiaddr.s_addr=inet_addr(HELLO_GROUP); mreq.imr_interface.s_addr=htonl(INADDR_ANY); if (setsockopt(fd,IPPROTO_IP,IP_ADD_MEMBERSHIP,&mreq,sizeof(mreq)) < 0) { perror("setsockopt"); exit(1); }

/* now just enter a read-print loop */ while (1) { addrlen=sizeof(addr); if ((nbytes=recvfrom(fd,msgbuf,MSGBUFSIZE,0, (struct sockaddr *) &addr,&addrlen)) < 0) { perror("recvfrom"); exit(1); } puts(message); } }

Чёртово форматирование.

Sender Program
/*
* sender.c -- multicasts "hello, world!" to a multicast group once a second
*
* Antony Courtney, 25/11/94
*/

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


#define HELLO_PORT 12345
#define HELLO_GROUP "225.0.0.37"

main(int argc, char *argv[])
{
struct sockaddr_in addr;
int fd, cnt;
struct ip_mreq mreq;
char *message="Hello, World!";

/* create what looks like an ordinary UDP socket */
if ((fd=socket(AF_INET,SOCK_DGRAM,0)) < 0) {
perror("socket");
exit(1);
}

/* set up destination address */
memset(&addr,0,sizeof(addr));
addr.sin_family=AF_INET;
addr.sin_addr.s_addr=inet_addr(HELLO_GROUP);
addr.sin_port=htons(HELLO_PORT);

/* now just sendto() our destination! */
while (1) {
if (sendto(fd,message,sizeof(message),0,(struct sockaddr *) &addr,
sizeof(addr)) < 0) {
perror("sendto");
exit(1);
}
sleep(1);
}
}



--------------------------------------------------------------------------------


Listener Program
/*
* listener.c -- joins a multicast group and echoes all data it receives from
* the group to its stdout...
*
* Antony Courtney, 25/11/94
*/

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


#define HELLO_PORT 12345
#define HELLO_GROUP "225.0.0.37"
#define MSGBUFSIZE 256

main(int argc, char *argv[])
{
struct sockaddr_in addr;
int fd, nbytes,addrlen;
struct ip_mreq mreq;
char msgbuf[MSGBUFSIZE];

/* create what looks like an ordinary UDP socket */
if ((fd=socket(AF_INET,SOCK_DGRAM,0)) < 0) {
perror("socket");
exit(1);
}

/* set up destination address */
memset(&addr,0,sizeof(addr));
addr.sin_family=AF_INET;
addr.sin_addr.s_addr=htonl(INADDR_ANY); /* N.B.: differs from sender */
addr.sin_port=htons(HELLO_PORT);

/* bind to receive address */
if (bind(fd,(struct sockaddr *) &addr,sizeof(addr)) < 0) {
perror("bind");
exit(1);
}

/* use setsockopt() to request that the kernel join a multicast group */
mreq.imr_multiaddr.s_addr=inet_addr(HELLO_GROUP);
mreq.imr_interface.s_addr=htonl(INADDR_ANY);
if (setsockopt(fd,IPPROTO_IP,IP_ADD_MEMBERSHIP,&mreq,sizeof(mreq)) < 0) {
perror("setsockopt");
exit(1);
}

/* now just enter a read-print loop */
while (1) {
addrlen=sizeof(addr);
if ((nbytes=recvfrom(fd,msgbuf,MSGBUFSIZE,0,
(struct sockaddr *) &addr,&addrlen)) < 0) {
perror("recvfrom");
exit(1);
}
puts(message);
}
}