r0 = socket$inet6_udp(0xa, 0x2, 0x0)
setsockopt$inet6_group_source_req(r0, 0x29, 0x19, &(0x7f0000002680)={0x0, {{0xa, 0x0, 0x0, @mcast1}}, {{0xa, 0x0, 0x0, @ipv4={'\x00', '\xff\xff', @multicast2}}}}, 0x3)