r0 = socket$inet(0x2, 0x3, 0xff)
r1 = dup(r0)
setsockopt$inet_mreq(r1, 0x0, 0x23, &(0x7f0000000000)={@multicast2, @loopback}, 0x8)
setsockopt$inet_MCAST_JOIN_GROUP(r0, 0x0, 0x2a, &(0x7f0000000040)={0x1, {{0x2, 0x0, @multicast1}}}, 0x88)