MCAST_JOIN_GROUP - ENODEV - No such device

[caipiblack]

Hello,

I am using libmicrodns on Linux and I have some issues with it:

• When the board is connected via Ethernet/WiFi: The function mdns_init() succeed.
• When the board is not connected via Ethernet/WiFi: The function mdns_init() fails.

As I also want it to work in local, it's a problem (I have an openthread border router, so avahi-daemon is running in local)

Here is the strace:

socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP) = 18
setsockopt(18, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
bind(18, {sa_family=AF_INET, sin_port=htons(5353), sin_addr=inet_addr("0.0.0.0")}, 16) = 0
setsockopt(18, SOL_IP, MCAST_JOIN_GROUP, {gr_interface=0, gr_group={sa_family=AF_INET, sin_port=htons(5353), sin_addr=inet_addr("224.0.0.251")}}, 132) = -1 ENODEV (No such device)
close(18)      

I tried to add "MULTICAST" to lo interface, but unfortunately it doesn't change the result.

I am using this commit: 8cb6b90