Multicast On Multiple Interfaces

receiver.c

#define WIN32_LEAN_AND_MEAN

#include <winsock2.h>
#include <Ws2tcpip.h>
#include <mswsock.h>

#include <stdio.h>

int main() {
    WSADATA wsaData;
    char opt;
    int err;
    
    err = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (err != 0) {
        printf("WSAStartup failed with the error: %d\n", err);
        return -1;
    }
    
    // Create The Socket
    SOCKET sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    
    // Set REUSEADDR Socket Option
    opt = TRUE;
    
    err = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
    if (err != 0) {
        printf("setsockopt failed with the error: %d\n", err);
        return -1;
    }
    
    // Subscribe To Multicast
    struct ip_mreq mcast_addr;
    mcast_addr.imr_multiaddr.s_addr = inet_addr("239.255.255.250");
    mcast_addr.imr_interface.s_addr = inet_addr("10.0.1.4");
    
    err = setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *) &mcast_addr, sizeof(struct ip_mreq));
    if (err != 0) {
        printf("setsockopt failed with the error: %d\n", err);
        return -1;
    }
    
    mcast_addr.imr_interface.s_addr = inet_addr("192.168.1.105");
    
    err = setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *) &mcast_addr, sizeof(struct ip_mreq));
    if (err != 0) {
        printf("setsockopt failed with the error: %d\n", err);
        return -1;
    }
    
    mcast_addr.imr_interface.s_addr = inet_addr("127.0.0.1");
    
    err = setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *) &mcast_addr, sizeof(struct ip_mreq));
    if (err != 0) {
        printf("setsockopt failed with the error: %d\n", err);
        return -1;
    }
    
    // Bind Socket
    struct sockaddr_in local_addr;
    local_addr.sin_family = AF_INET;
    local_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    local_addr.sin_port = htons(1900);
    
    err = bind(sock, (SOCKADDR*) &local_addr, sizeof(local_addr));
    if (err != 0) {
        printf("bind failed with the error: %d\n", err);
        return -1;
    }
    
    // Listen For Data
    char recv_buff[500];
    int recv_len = sizeof(recv_buff), result = 0;
    while (1) {
        result = recv(sock, recv_buff, recv_len, 0);
        
        if (result > 0) {
            printf("Received %d Bytes\n", result);
            int i;
            for (i = 0; i < result; ++i) {
                printf("%c", recv_buff[i]);
            }
        } else {
            printf("Err Connection: %d\n", result);
            return -1;
        }
    }
}