testcases/network/multicast/mc_member/member.c

#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netdb.h>
#include <unistd.h>

char *prog;
int errors=0;
int ttl_no=255;

int join_group (int, char *, struct ip_mreq *);
int leave_group (int, char *, struct ip_mreq *);
void usage(void);

int main(argc, argv)
int argc;
char *argv[];
{
        int s;
        struct ip_mreq imr;

        char *group_list=NULL, *interface=NULL;
        unsigned i1, i2, i3, i4;
        struct hostent *hp, *gethostbyname();
	int c, n;
        /*int errors=0;*/
        int lflg=0, jflg=0, sflg=0;

        extern int optind;
        extern char *optarg;
        prog = argv[0];
        if (argc == 1)
            usage ();

        while ((c = getopt(argc,argv,"jlg:s:i:")) != EOF)
        	switch (c)
                {
                	case 'j':
				if (lflg)
					usage();
                                else
                                	jflg++;
                                break;
                        case 'l':
                                if (jflg)
                                        usage();
                                else
                                        lflg++;
                                break;
                        case 'g':
                                group_list = optarg;
                                break;
                        case 's':
                                sflg=atoi(optarg);
				break;
			case 'i':
				interface = optarg;
                                break;
                        case '?':
                                usage();
               }

        if (optind != argc)
           usage ();

        if (access (group_list, R_OK) != 0) {
                printf ("Unabled to read group file %s\n",group_list);
                exit (1);
        }

        if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
            perror( "can not open socket" );
            exit(1);
        }

        if ((hp = gethostbyname(interface))) {
           memcpy(&imr.imr_interface.s_addr, hp->h_addr, hp->h_length);
        } else
           if ((n = sscanf(interface, "%u.%u.%u.%u", &i1, &i2, &i3, &i4)) != 4) {
              fprintf(stderr, "bad group address\n" );
              exit (1);
           } else
              imr.imr_interface.s_addr =
                                 htonl((i1<<24) | (i2<<16) | (i3<<8) | i4);
        /* verify socket options */
	if ( setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
                        &imr.imr_interface.s_addr,
                        sizeof(imr.imr_interface.s_addr)) != 0 ) {
           fprintf(stderr,"Error: unable to set socket option IP_MULTICAST_IF\n");
           errors++;
	} else
	   printf("Socket set for Multicasting on: %s\n",interface);

        if ((!jflg && !lflg) || jflg)
           join_group ( s, group_list, &imr );

        sleep (sflg);

        if ((!jflg && !lflg) || lflg)
           leave_group ( s, group_list, &imr );

        close (s);
        if (errors)
           exit (1);
        return (0);
}

int join_group (int s, char *glist, struct ip_mreq *imr)
{
        char buf[40];
        unsigned g1, g2, g3, g4;
        FILE *fd;
        char group[40], itf[40];

        if ((fd = fopen(glist,"r")) == NULL)
           printf ("Error: unable to open %s\n",glist);

        while (fgets(buf, sizeof(buf), fd) != NULL) {
           if (sscanf(buf, "%u.%u.%u.%u", &g1, &g2, &g3, &g4) != 4) {
             fprintf(stderr, "bad group address\n" );
             exit(1);
           }

           imr->imr_multiaddr.s_addr = htonl((g1<<24) | (g2<<16) | (g3<<8) | g4);

           if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP,
                         imr, sizeof(struct ip_mreq)) == -1) {
              fprintf(stderr, "errno is %d \n", errno);
              perror("can't join group");
              errors++;
           } else {
              strcpy (group,inet_ntoa(imr->imr_multiaddr));
              strcpy (itf,inet_ntoa(imr->imr_interface));
              printf ("IPM group: %s added to interface: %s\n",group,itf);
           }
        }
        return (0);
}

int leave_group (int s, char *glist, struct ip_mreq *imr)
{
        char buf[40];
        unsigned g1, g2, g3, g4;
        FILE *fd;
        char group[40], itf[40];

        if ((fd = fopen(glist,"r")) == NULL)
           printf ("Error: unable to open %s\n",glist);

        while (fgets(buf, sizeof(buf), fd) != NULL) {
           if (sscanf(buf, "%u.%u.%u.%u", &g1, &g2, &g3, &g4) != 4) {
             fprintf(stderr, "leave_group: bad group address\n" );
             exit(1);
           }

           imr->imr_multiaddr.s_addr =
                                      htonl((g1<<24) | (g2<<16) | (g3<<8) | g4);

           if (setsockopt(s, IPPROTO_IP, IP_DROP_MEMBERSHIP,
                         imr, sizeof(struct ip_mreq)) == -1) {
              perror("can't leave group");
              errors++;
           } else {
              strcpy (group,inet_ntoa(imr->imr_multiaddr));
              strcpy (itf,inet_ntoa(imr->imr_interface));
              printf ("IPM group: %s dropped from interface: %s\n",group,itf);
           }
        }
        return (0);
}

void usage()
{
           fprintf(stderr,
              "usage: %s [ -j -l ] -g group_list [-s time_to_sleep] -i interface_name (or i.i.i.i)\n",prog);
           exit( 1);
}