On Mon, Dec 30, 2013 at 10:06:32AM -0800, Ben Pfaff wrote:
> On Tue, Dec 24, 2013 at 04:35:57PM +0900, Simon Horman wrote:
> > On Tue, Dec 17, 2013 at 05:08:35PM -0800, Ben Pfaff wrote:
> > > On Mon, Dec 16, 2013 at 05:57:52PM +0900, Simon Horman wrote:
> > > > If VLAN acceleration is used when the kernel receives a packet
> > > > then the outer-most VLAN tag will not be present in the packet
> > > > when it is received by netdev-linux. Rather, it will be present
> > > > in auxdata.
> > > >
> > > > This patch uses recvmsg() instead of recv() to read auxdata for
> > > > each packet and if the vlan_tid is set then it is added to the packet.
> > > >
> > > > Adding the vlan_tid makes use of headroom available
> > > > in the buffer parameter of rx_recv.
> > > >
> > > > Signed-off-by: Simon Horman <ho...@verge.net.au>
> > >
> > > This patch should be Linux-specific, why does it update netdev-bsd?
> > >
> > > I think we should add a comment to netdev_rx_recv() explaining how the
> > > tailroom in the buffer may get used (you might need 4 bytes more
> > > tailroom than the actual MTU, and you might get 4 bytes of extra
> > > headroom in the result).
> >
> > Sure, how about this?
> >
> > /* Attempts to receive a packet from 'rx' into 'buffer'.
> > * If successful, returns 0 and increments the 'size' field of 'buffer'
> > * by the number of bytes in the received packet, otherwise a positive
> > * errno value. Returns EAGAIN immediately if no packet is ready to
> > * be received.
> > *
> > * Must return EMSGSIZE, and discard the packet, if the received packet
> > * is longer than the tailroom of 'buffer'.
> > *
> > * Implementations may make use of VLAN_HEADER_LEN bytes of tailroom to
> > * add a VLAN header which is obtained out-of-band to the packet. If
> > * this occurs then VLAN_HEADER_LEN bytes of tailroom will no longer be
> > * available for the packet, otherwise it may be used for the packet
> > * itself.
> > *
> > * It is advised that the tailroom of 'buffer' should be
> > * VLAN_HEADER_LEN bytes longer than the MTU to allow space for an
> > * out-of-band VLAN header to be added to the packet.
> > *
> > * Specify NULL if this */
>
> That's OK except for the last sentence fragment.
The last sentence fragment is unchanged from the current code.
Should I update it to the following to be in line
with other netdev classes?
* This function may be set to null if it would always return EOPNOTSUPP
* anyhow. */
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