diff options
Diffstat (limited to 'mcast/mcast.c')
| -rw-r--r-- | mcast/mcast.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/mcast/mcast.c b/mcast/mcast.c new file mode 100644 index 0000000..c1becc5 --- /dev/null +++ b/mcast/mcast.c @@ -0,0 +1,159 @@ +#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) ? mhost : "NULL") ); + 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); + } + } + } +} |