r0 = socket$inet6_udp(0xa, 0x2, 0x0)
ioctl$sock_ipv6_tunnel_SIOCADDTUNNEL(r0, 0xc0189436, &(0x7f0000000200)={'sit0\x00', &(0x7f0000000000)={'syztnl0\x00', 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, @ipv4={'\x00', '\xff\xff', @dev}, @initdev={0xfe, 0x88, '\x00', 0x0, 0x0}}})