IP_BLOCK_SOURCE or IP_DROP_MEMBERSHIP does not have an effect for igmp socket

client.sh

# ip of enp0s8: 192.168.50.98
mcjoin -i enp0s8  -t 200 -f 500  -s 224.20.30.40

receiver_igmp.c

#include <stdio.h>          /* printf(), snprintf() */
#include <stdlib.h>         /* strtol(), exit() */
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/socket.h>     /* socket(), setsockopt(), bind(),
                               recvfrom(), sendto() */
#include <errno.h>          /* perror() */
#include <netinet/in.h>     /* IPPROTO_IP, sockaddr_in, htons(),*/
#include <linux/mroute.h>

#include <arpa/inet.h>      /* inet_addr() */
#include <unistd.h>         /* fork(), sleep() */
#include <sys/utsname.h>    /* uname() */
#include <string.h>         /* memset() */
int main (int argc, char *argv[])
{
        struct sockaddr_in localSock;
        struct ip_mreq group;
        struct ip_mreq_source source_group;
        int recvfd;
        int datalen, ret;
        int buflen = 128;
        char igmpbuf[buflen];

        // create socket
        recvfd = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP);
        int v = 1;
        setsockopt(recvfd, IPPROTO_IP, MRT_INIT, (void *)&v, sizeof(v));

        // assign vif
        struct vifctl vc;
        memset(&vc, 0, sizeof(vc));
        vc.vifc_vifi = 3;
        vc.vifc_flags = 0;
        vc.vifc_flags |= 8;
        vc.vifc_rate_limit = 0;
        vc.vifc_lcl_ifindex = 3;
        setsockopt(recvfd, IPPROTO_IP, MRT_ADD_VIF, (void *)&vc,
                        sizeof(vc));

        // join group
        group.imr_multiaddr.s_addr = inet_addr("224.20.30.40");
        group.imr_interface.s_addr = inet_addr("192.168.50.155");
        setsockopt(recvfd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
                        (char *)&group, sizeof(group));

        // block source from 192.168.50.98, comment this code block out affects
        // nothing.
        source_group.imr_multiaddr.s_addr = inet_addr("224.20.30.40");
        source_group.imr_interface.s_addr = inet_addr("192.168.50.155");
        source_group.imr_sourceaddr.s_addr = inet_addr("192.168.50.98");
        setsockopt(recvfd, IPPROTO_IP, IP_BLOCK_SOURCE,
                        (char *)&source_group, sizeof(source_group));

        // Read from the socket.
        datalen = sizeof(igmpbuf);
        while (1){
                bzero(igmpbuf, buflen);
                ret = read(recvfd, igmpbuf, datalen);

                if (igmpbuf[9] == 0 && igmpbuf[15] == 98 ){
                        printf("\nlen: %d\n", ret);
                        for (int i=0; i < ret; i++){
                                // will receive IGMPMSG from 192.168.50.98
                                printf("%d %#x \n",i, igmpbuf[i]);
                        }
                }
        }
        close(recvfd);
        return 0;
}

receiver_udp.c

#include <stdio.h>          /* printf(), snprintf() */
#include <stdlib.h>         /* strtol(), exit() */
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/socket.h>     /* socket(), setsockopt(), bind(),
                               recvfrom(), sendto() */
#include <errno.h>          /* perror() */
#include <netinet/in.h>     /* IPPROTO_IP, sockaddr_in, htons(),*/
#include <linux/mroute.h>

#include <arpa/inet.h>      /* inet_addr() */
#include <unistd.h>         /* fork(), sleep() */
#include <sys/utsname.h>    /* uname() */
#include <string.h>         /* memset() */
int main (int argc, char *argv[])
{
        struct sockaddr_in localSock;
        struct ip_mreq group;
        struct ip_mreq_source source_group;
        int recvfd;
        int datalen, ret;
        char igmpbuf[128];

        // Create a datagram socket on which to receive.
        recvfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

        // Bind to the proper port number with the IP address
        // specified as INADDR_ANY.
        memset((char *) &localSock, 0, sizeof(localSock));
        localSock.sin_family = AF_INET;
        localSock.sin_port = htons(1234);;
        localSock.sin_addr.s_addr = INADDR_ANY;
        bind(recvfd, (struct sockaddr*)&localSock, sizeof(localSock));

        // Join multicast group
        group.imr_multiaddr.s_addr = inet_addr("224.20.30.40");
        group.imr_interface.s_addr = inet_addr("192.168.50.155");
        setsockopt(recvfd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
                        (char *)&group, sizeof(group));

        // block source from 192.168.50.98, comment this code block the socket will
        // able to receiver udp traffic from 192.168.50.98
        source_group.imr_multiaddr.s_addr = inet_addr("224.20.30.40");
        source_group.imr_interface.s_addr = inet_addr("192.168.50.155");
        source_group.imr_sourceaddr.s_addr = inet_addr("192.168.50.98");
        // both IP_BLOCK_SOURCE and IP_DROP_SOURCE_MEMBERSHIP works
        setsockopt(recvfd, IPPROTO_IP, IP_BLOCK_SOURCE,
                        (char *)&source_group, sizeof(source_group));

        // Read from the socket.
        datalen = sizeof(igmpbuf);
        while (1){
                bzero(igmpbuf, 128);
                ret = read(recvfd, igmpbuf, datalen);

                printf("\nlen: %x\n", ret);
                for (int i=0; i < ret; i++){
                        printf("%d %#x \n",i, igmpbuf[i]);
                }
        }
        close(recvfd);

        return 0;
}