c++socketsudpmpeg2-tsmulticastsocket

C++ How can i join to a multicast mpeg stream?


How can i manage to join a multicast mpeg stream group with an address of udp://@224.1.50.15:1234? What i want to manage is just to make a connection with the stream server to make the server become aware of that i am interested in this multicast group to make the server to send me the stream packets for a period of a time.

For an example: I am not receiving any packets from this multicast group until i establish a connection to the group with VLC Player. Even after i close the VLC Player i keep receiving packets from the group for a short period of time. What i am trying to do is to receive the packets without the help of VLC Player or any other third party application.

How can i manage to make a connection with this group for the purpose above. If it is even possible?

P.S: I have 4 network interfaces installed.

Thank you!

As the recommendation of Zaboj Campula in his answer in this page; i changed the code as below. Which gives me an error 10093.

struct ip_mreq {
    struct in_addr imr_multiaddr;   /* IP multicast address of group */
    struct in_addr imr_interface;   /* local IP address of interface */
};
SOCKET        s;
SOCKADDR_IN    localif;
struct ip_mreq mreq;
s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
localif.sin_family = AF_INET;
localif.sin_port = htons(1234);
localif.sin_addr.s_addr = INADDR_ANY;
bind(s, (SOCKADDR *)&localif, sizeof(localif));
mreq.imr_interface.s_addr = INADDR_ANY; //Writing here my local ip didn't change the result.
mreq.imr_multiaddr.s_addr = inet_addr("224.1.50.15");
int rc = NO_ERROR;
s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
// Join the group
rc = setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&mreq, sizeof(mreq));
if (rc == SOCKET_ERROR)
{
    printf("JoinMulticastGroup: setsockopt failed with error code %d\n", WSAGetLastError());
}
else
{
    printf("Joined group: ");
    //PrintAddress(group->ai_addr, group->ai_addrlen);
    printf("\n");
}

Solution

  • Ok, I managed to resolve my issue with the help of the book Multicast Sockets Practical Guide for Programmers which is written by David Makofske & Kevin Almeroth

    Thank's goes to the writers and Zaboj Campula for their efforts.

    I hope this post and the answer will help many others in the future. The working code is written below! Compiled with Visual Studio 2017 RC (Console Empty C project)

    int sock;                     /* socket descriptor */
    int flag_on = 1;              /* socket option flag */
    struct sockaddr_in mc_addr;   /* socket address structure */
    char recv_str[MAX_LEN + 1];     /* buffer to receive string */
    int recv_len;                 /* length of string received */
    struct ip_mreq mc_req;        /* multicast request structure */
    char* mc_addr_str;            /* multicast IP address */
    unsigned short mc_port;       /* multicast port */
    struct sockaddr_in from_addr; /* packet source */
    unsigned int from_len;        /* source addr length */
    WSADATA wsaData;              /* Windows socket DLL structure */
    
    mc_addr_str = "224.1.50.15";      /* arg 1: multicast ip address */
    mc_port = atoi("1234");    /* arg 2: multicast port number */
    
                                /* validate the port range */
    if ((mc_port < MIN_PORT) || (mc_port > MAX_PORT)) {
        fprintf(stderr, "Invalid port number argument %d.\n",
            mc_port);
        fprintf(stderr, "Valid range is between %d and %d.\n",
            MIN_PORT, MAX_PORT);
        exit(1);
    }
    
    /* Load Winsock 2.0 DLL */
    if (WSAStartup(MAKEWORD(2, 0), &wsaData) != 0) {
        fprintf(stderr, "WSAStartup() failed");
        exit(1);
    }
    
    /* create socket to join multicast group on */
    if ((sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
        perror("socket() failed");
        exit(1);
    }
    
    /* set reuse port to on to allow multiple binds per host */
    if ((setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char*)&flag_on,
        sizeof(flag_on))) < 0) {
        perror("setsockopt() failed");
        exit(1);
    }
    
    /* construct a multicast address structure */
    memset(&mc_addr, 0, sizeof(mc_addr));
    mc_addr.sin_family = AF_INET;
    mc_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    mc_addr.sin_port = htons(mc_port);
    
    /* bind to multicast address to socket */
    if ((bind(sock, (struct sockaddr *) &mc_addr,
        sizeof(mc_addr))) < 0) {
        perror("bind() failed");
        exit(1);
    }
    
    /* construct an IGMP join request structure */
    mc_req.imr_multiaddr.s_addr = inet_addr(mc_addr_str);
    mc_req.imr_interface.s_addr = htonl(INADDR_ANY);
    
    /* send an ADD MEMBERSHIP message via setsockopt */
    if ((setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
        (char*)&mc_req, sizeof(mc_req))) < 0) {
        perror("setsockopt() failed");
        exit(1);
    }
    
    for (;;) {          /* loop forever */
    
                        /* clear the receive buffers & structs */
        memset(recv_str, 0, sizeof(recv_str));
        from_len = sizeof(from_addr);
        memset(&from_addr, 0, from_len);
    
        /* block waiting to receive a packet */
        if ((recv_len = recvfrom(sock, recv_str, MAX_LEN, 0,
            (struct sockaddr*)&from_addr, &from_len)) < 0) {
            perror("recvfrom() failed");
            exit(1);
        }
    
        /* output received string */
        printf("Received %d bytes from %s: ", recv_len,
            inet_ntoa(from_addr.sin_addr));
        printf("%s", recv_str);
    }
    
    /* send a DROP MEMBERSHIP message via setsockopt */
    if ((setsockopt(sock, IPPROTO_IP, IP_DROP_MEMBERSHIP,
        (void*)&mc_req, sizeof(mc_req))) < 0) {
        perror("setsockopt() failed");
        exit(1);
    }
    
    closesocket(sock);
    WSACleanup();  /* Cleanup Winsock */