IPv6 multicast on ETH interface

[QuentinCaldeira-eaton]

Hi, I would like to know if it's possible to have multiple IP address for one Ethernet port. I think my application need at least one link-local and one multicast IP Address. I'm doing like this :

struct net_if *iface;
struct in6_addr my_ipv6_addr;
struct in6_addr my_ipv6_mcast_addr;

iface = net_if_get_default();

net_addr_pton(AF_INET6, "2001:db8::1", &my_ipv6_addr);
net_if_ipv6_addr_add(iface, &my_ipv6_addr, NET_ADDR_MANUAL, 0);

net_addr_pton(AF_INET6, "ff02::1", &my_ipv6_mcast_addr);
net_if_ipv6_maddr_add(iface, &my_ipv6_mcast_addr);

But I don't think this is the right way to go. Any ideas ? Thanks :)

[mariopaja]

@QuentinCaldeira-eaton Yes it is possible.

This is on Zephy 2.7 but the idea should be more or less the same

    /* Setup UNICAST socket */
    net_addr_ntop(AF_INET, &iface->config.ip.ipv4->unicast[0].address.in_addr, ucast_IP, sizeof(ucast_IP));

    struct sockaddr_in ucast_addr4;
    ucast_addr4.sin_family = AF_INET;
    ucast_addr4.sin_port = htons(4242);
    zsock_inet_pton(AF_INET, &ucast_IP[0], &ucast_addr4.sin_addr);
    int sock_ucast = zsock_socket(ucast_addr4.sin_family, SOCK_DGRAM, IPPROTO_UDP);

    /* Join IGMP group */
    ret = net_ipv4_igmp_join(iface, &mcast_addr);

    /* Setup MULTICAST socket */
    net_addr_ntop(AF_INET, &iface->config.ip.ipv4->mcast[0].address.in_addr, mcast_IP, sizeof(mcast_IP));

    struct sockaddr_in mcast_addr4;
    mcast_addr4.sin_family = AF_INET;
    mcast_addr4.sin_port = htons(5000);
    zsock_inet_pton(AF_INET, &mcast_IP[0], &mcast_addr4.sin_addr);
    int sock_mcast = zsock_socket(mcast_addr4.sin_family, SOCK_DGRAM, IPPROTO_UDP);

    /* Bind to UNICAST & MULTICAST sockets */
    ret = zsock_bind(sock_ucast, (const struct sockaddr *)&ucast_addr4, sizeof(ucast_addr4));
    ret = zsock_bind(sock_mcast, (const struct sockaddr *)&mcast_addr4, sizeof(mcast_addr4));

[QuentinCaldeira-eaton]

Thanks, it's quite similar to what I've done. Idk if sockets are mandatory, but I will try. Also, is it normal that my device doesn't appears in my router interface ?

[mariopaja]

@QuentinCaldeira-eaton

Idk if sockets are mandatory

I dont think they are mandatory. I just sent this as an example. In my case we receive an IP via DHCP and after that we join to a multicast group.