openflow - Ryu framework, tcp_flags in parser.OFPMatch -

i trying match flow in openflow-compatible switch (openflow 1.5) using ryu framework.

as far know, openflow version 1.5 supports 'tcp_flags' match conditions, , ryu does.

so, when trying code like:

    match = parser.ofpmatch(         tcp_flags=0x000         ) 

nothing happens in flow table, while expecting occur new flow entry.

ingress packet contains empty value tcp flags.

does knows, how code such kind of condition in ryu?

thanks.

match = parser.ofpmatch(     eth_type=0x0800,      ip_proto=6,      tcp_flags=0x000     ) 

solved problem. according 'openflow switch specification', before use of 'tcp_flags', prerequisite fields should met. in case, 'tcp_flags' field needs 'eth_type = 0x8000' , 'ip_proto = 6' fields placed before.