r0 = socket$inet6_tcp(0xa, 0x1, 0x0)
setsockopt$inet6_IPV6_FLOWLABEL_MGR(r0, 0x29, 0x20, &(0x7f0000000140)={@mcast2, 0x0, 0x1, 0x0, 0x6}, 0x20)