> >greater than the maximum header size which is configurable. In the case > >of VXLAN / STT we can be in the case above, because of the UDP/TCP like > >packet > > [Nithin]: Yes, in fact even for NICs that support header-split (mostly Intel), [Alin Gabriel Serdean: ] I looked over some Intel specs and they said you could header split after eth header on a RQ. The documentation is very shady between NDIS versions, you are right, I will allocate a buffer if the memory was not contiguous. I found this in the document when header data split was introduced: " • Do not assume that the minimum size of the data in the first MDL contains all of the TCP/IP headers." Thanks for the patience of reiterating that we should not make assumptions :). > the payload of the packet WILL NOT be in the first MDL. In case of GRE, the > split would happen at the IP header itself. So, GRE header would not be in > the contigous buffer. > > >, but for GRE things differ since there are cards which support > >offloading: > >https://urldefense.proofpoint.com/v2/url?u=https- > 3A__msdn.microsoft.com > >_en > >-2Dus_library_windows_hardware_dn605832-28v-3Dvs.85- > 29.aspx&d=CwIFAA&c= > >Sqc > >l0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt- > uEs&r=pNHQcdr7B40b4h6Yb7FIedI1dnBs > >xdD > >uTLBYD3JqV80&m=Xih_0c1MPDafKSkW1nO5- > mIutm1WK_ZmMcu7likx3jM&s=A4LA4vS20h > >f4l > >keq-wjCc6N9kbBMqswRnC-SSulTF6s&e= > >"The protocol driver will guarantee that all the prepended > >encapsulation headers (ETH, IP, GRE) will be physically contiguous and > >will be in the first MDL of the packet." > > > >I do not think we will be in a situation in which a GRE header will not > >be continuous. > >If you consider we should still have a fragmented header problem, I > >will allocate a buffer and execute another NdisGetDataBuffer call if > >the first one failed. > > [Nithin]: The documention you point to is to the send direction. In case of > receive, where does it say that the protocol/filter driver can expect the > miniport driver to pack the ETH + IP + GRE header in one contiguous buffer? [Alin Gabriel Serdean: ] https://msdn.microsoft.com/en-us/library/windows/hardware/dn605831(v=vs.85).aspx > > In any case, if you are particular that the code is correct, I am ok with the > patch. I was trying to give suggestions to make the code solid. > > Acked-by: Nithin Raju <nit...@vmware.com> > > -- Nithin
_______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
