r0 = socket$inet6_udp(0xa, 0x2, 0x0)
ioctl$sock_inet6_SIOCDELRT(r0, 0x890c, &(0x7f00000021c0)={@local, @mcast1, @private1, 0x0, 0xfffb, 0x0, 0x0, 0x0, 0x31c0081})