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#include <stdio.h>
#include <sys/file.h>
#include <sys/types.h>
#ifdef __Lynx__
#include <socket.h>
#else
#include <sys/socket.h>
#endif
#include <net/if.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <stdlib.h>
#include <inttypes.h>
#include <string.h>
#include "mcast_params.h"
#define ROUTERS_TO_HOP 10 // Keep my traffic in the same subnet
static struct sockaddr_in addr;
static int so;
static char mhost[100];
static unsigned long hostaddr;
int msend(char *buf, int num)
{
bzero(&addr, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons((u_short)MCAST_PORT);
addr.sin_addr.s_addr = inet_addr(MCAST_ADDR);
if (sendto(so, buf, num, 0, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
if (errno != EAGAIN)
perror("sendto");
return 0;
}
return 1;
}
int mrecv(char *buf, int num)
{
socklen_t i;
int n;
bzero(&addr, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons((u_short)MCAST_PORT);
addr.sin_addr.s_addr = inet_addr(MCAST_ADDR);
i = sizeof(addr);
if ((n = recvfrom(so, buf, num, 0, (struct sockaddr *)&addr, &i)) == -1) {
if (errno != EAGAIN)
perror("recvfrom");
return 0;
}
return n;
}
#if defined(__rtems__)
int mcast_main(int ac, char **av)
#else
int main(int ac, char **av)
#endif
{
int yes=1;
char line[1024];
struct ip_mreq imr;
struct hostent *h;
unsigned char mttl;
int mlen;
unsigned long long i, j, k;
if (ac > 1) mlen = atoi(av[1]);
else mlen = 0;
if ((gethostname(mhost, 100) < 0)) { // Get the my hostname
perror("gethostname");
exit(1);
}
printf( "Hostname: %s\n", mhost );
if (!(h = gethostbyname(mhost))) { // Get host entry
perror("gethostbyname");
exit(1);
}
printf( "host=0x%08x\n", *(unsigned int *)h->h_addr );
printf( "Creating socket\n" );
if ((so = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
perror("socket");
exit(1);
}
printf( "Setting SO_REUSEADDR\n" );
if (setsockopt(so, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0) {
perror("setsockopt, reuse");
exit(1);
}
printf( "Binding\n" );
// Bind to port and address.
bzero(&addr, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons((u_short)MCAST_PORT);
addr.sin_addr.s_addr = INADDR_ANY;
if (bind(so, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
perror("bind");
exit(1);
}
printf( "Performing IP_MULTICAST_TTL\n" );
mttl = ROUTERS_TO_HOP + 1; // ttl should be atleast one.
if (setsockopt(so, IPPROTO_IP, IP_MULTICAST_TTL, &mttl, sizeof(mttl)) < 0) {
perror("setsockopt, ttl" );
exit(1);
}
hostaddr = *(unsigned int *)h->h_addr;
imr.imr_interface.s_addr = htonl(INADDR_ANY);
// For some reason, this doesn't seem to work. I suspect it is because
// the /etc/hosts included with this demo must match the IP of the
// network interface you want to use. I couldn't get this to work
// so gave up. INADDR_ANY seems to reliably find the NIC. --joel
// imr.imr_interface.s_addr = hostaddr;
imr.imr_multiaddr.s_addr = inet_addr(MCAST_ADDR);
printf( "Performing IP_ADD_MEMBERSHIP\n" );
if (setsockopt(so, IPPROTO_IP, IP_ADD_MEMBERSHIP, &imr, sizeof(imr)) < 0) {
perror( "can't join group" );
close(so);
exit(1);
}
fcntl(so, F_SETFL, FNDELAY);
j = k = 0;
for(i = 1; 1; i++) {
int x;
if (i == 0) j++;
if (j == 0) k++;
sleep(1);
sprintf(line,
"%s i %" PRId64 ", j %" PRId64 ", k %" PRId64 "", mhost, i, j, k);
msend(line, strlen(line)+ mlen);
while ((x = mrecv(line, 500)) > 0) {
if (addr.sin_addr.s_addr != hostaddr) {
line[x] = 0;
printf("Raddr %s recv %s\n", inet_ntoa(addr.sin_addr), line);
}
}
}
}
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