On Sun, May 1, 2016 at 11:51 PM, Peter Palúch <peter.pal...@fri.uniza.sk> wrote: > Hi Ran, > > >> Alex, >> I don't see rx-vlan-offload option in my ethtool. strange, maybe it is >> not available in all ethtool versions ? > > > According to my manpage for ethtool v4.5, the relevant -K option is > "rxvlan". > >> Hi Peter, >> Yes, I'm using AF_PACKET (I can't validate it now for 100%, but I >> quite sure about it). > > > Okay - but I assume that you are writing a userspace application, not a > kernelspace driver or module, right? > >> I'm accessing the ethernet header, and it always gives me non extended >> ethernet header (without vlan information). > > > It seems that this behavior has been around for a long time, and is > intentional. See the following thread for more information: > > http://www.spinics.net/lists/netdev/msg244668.html > > The only legit way of accessing VLAN tag info on an AF_PACKET socket I know > about is by setting the PACKET_AUXDATA socket option, and reading the > auxiliary data as a struct tpacket_auxdata using recvmsg(). > > In addition, however, there seems to be a bug in the kernel in that the > tp_vlan_tci member of the struct tpacket_auxdata is filled in only if the > AF_PACKET socket is bound to htons(ETH_P_ALL). If the socket is bound to any > other specific protocol, the tp_vlan_tci is set to 0. I have raised this > issue recently in the following thread(s) but have not received a response > yet: > > http://www.spinics.net/lists/netdev/msg372830.html > http://www.spinics.net/lists/netdev/msg373112.html > > >> I can see the vlan tag in vlan_tci field in sk_buff, but this is not >> exactly what I need, I need the header AS-IS with the original >> (extended) ethernet header. > > > How are you accessing the vlan_tci field from your software? > > In any case, with AF_PACKET sockets, I am afraid you don't have much choice. > Even libpcap reconstructs VLAN-tagged frames by reading the VLAN tag from an > auxiliary structure and then re-inserting it into the frame, because the > frame delivered through an AF_PACKET socket does not have the VLAN tag > present anymore. >
Hi Peter, I have a patch (hook) in the igb (Intel) driver which reads the skb buffer into our buffer, this is without using socket actually. ipstack is not involved, so socket as I mentioned before are not relevant (AF_PACKET not relevant). the problem seems in the driver that the driver strip vlan information (there is a lot of mention of strip and vlan in the igb driver, and I tried many things, but still it always strip this information from the data in the sk_buff.) will ethtool assist in this case ? I don;t see any vlan option in my ethtool. Does ethtool communicated with the driver and command it not to strip the vlan info ? Thanks, Ran
