[ovs-dev,v6,2/5] userspace: L3 tunnel support for GRE and LISP

> I think that parse_gre_header() should perhaps be pickier about the
> Ethertypes it accepts, since values below 0x600 are not valid
> Ethertypes and sometimes they are used for special purposes, for example
> OpenFlow uses 0x5ff to mean that the frame lacks an Ethertype.

I agree. OVS could just drop packets from GRE tunnels with GRE protocols < 0x600.

> 
> I recommend adding an item to NEWS to mention this new user-visible
> feature.

What about:


> 
> Ideally, some new documentation would explain how layer 2 and 3 packets
> interact.

I am planning for proper documentation along the lines of the Google doc as part of the overall PTAP and generic Encap/Decap patch complex.

Can you recommend a good authoring tool for the .rst format used in OVS lately?

BR, Jan

On Mon, May 22, 2017 at 01:43:25PM +0000, Jan Scheurich wrote:
> > I think that parse_gre_header() should perhaps be pickier about the
> > Ethertypes it accepts, since values below 0x600 are not valid
> > Ethertypes and sometimes they are used for special purposes, for example
> > OpenFlow uses 0x5ff to mean that the frame lacks an Ethertype.
> 
> I agree. OVS could just drop packets from GRE tunnels with GRE protocols < 0x600.
> 
> > 
> > I recommend adding an item to NEWS to mention this new user-visible
> > feature.
> 
> What about:
> 
> diff --git a/NEWS b/NEWS
> index 25eb477..bbed787 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -45,6 +45,12 @@ Post-v2.7.0
>     - Fedora Packaging:
>       * OVN services are no longer restarted automatically after upgrade.
>     - Add --cleanup option to command 'ovs-appctl exit' (see ovs-vswitchd(8)).
> +   - L3 tunneling:
> +     * Add "layer3" options for tunnel ports that support non-Ethernet (L3)
> +       payload (GRE, VXLAN-GPE).
> +     * New vxlan tunnel extension "gpe" to support VXLAN-GPE tunnels.
> +     * Transparently pop and push Ethernet headers at transmit/reception
> +       of packets to/from L3 tunnels.

Sure, thanks!

> > Ideally, some new documentation would explain how layer 2 and 3 packets
> > interact.
> 
> I am planning for proper documentation along the lines of the Google doc as part of the overall PTAP and generic Encap/Decap patch complex.
> 
> Can you recommend a good authoring tool for the .rst format used in OVS lately?

I use Emacs, which is only so-so at RST, so I don't have a good
recommendation.  Stephen, what do you use?

On Thu, 2017-05-25 at 09:22 -0700, Ben Pfaff wrote:
> On Mon, May 22, 2017 at 01:43:25PM +0000, Jan Scheurich wrote:
> > > I think that parse_gre_header() should perhaps be pickier about
> > > the
> > > Ethertypes it accepts, since values below 0x600 are not valid
> > > Ethertypes and sometimes they are used for special purposes, for
> > > example
> > > OpenFlow uses 0x5ff to mean that the frame lacks an Ethertype.
> > 
> > I agree. OVS could just drop packets from GRE tunnels with GRE
> > protocols < 0x600.
> > 
> > > 
> > > I recommend adding an item to NEWS to mention this new user-
> > > visible
> > > feature.
> > 
> > What about:
> > 
> > diff --git a/NEWS b/NEWS
> > index 25eb477..bbed787 100644
> > --- a/NEWS
> > +++ b/NEWS
> > @@ -45,6 +45,12 @@ Post-v2.7.0
> >     - Fedora Packaging:
> >       * OVN services are no longer restarted automatically after
> > upgrade.
> >     - Add --cleanup option to command 'ovs-appctl exit' (see ovs-
> > vswitchd(8)).
> > +   - L3 tunneling:
> > +     * Add "layer3" options for tunnel ports that support non-
> > Ethernet (L3)
> > +       payload (GRE, VXLAN-GPE).
> > +     * New vxlan tunnel extension "gpe" to support VXLAN-GPE
> > tunnels.
> > +     * Transparently pop and push Ethernet headers at
> > transmit/reception
> > +       of packets to/from L3 tunnels.
> 
> Sure, thanks!
> 
> > > Ideally, some new documentation would explain how layer 2 and 3
> > > packets
> > > interact.
> > 
> > I am planning for proper documentation along the lines of the
> > Google doc as part of the overall PTAP and generic Encap/Decap
> > patch complex.
> > 
> > Can you recommend a good authoring tool for the .rst format used in
> > OVS lately?
> 
> I use Emacs, which is only so-so at RST, so I don't have a good
> recommendation.  Stephen, what do you use?

There's a good section in the docs about this:

  http://docs.openvswitch.org/en/latest/internals/contributing/document
ation-style/#helpful-tools

Personally, I use vim with the 'scrooloose/syntastic' plugin and the
following autocmd snippet:

  if has("autocmd")
      au FileType rst setlocal textwidth=79 spell
  endif

...which will force wrapping and enable spell check. All the good stuff
is in my dotfiles repo:

  https://github.com/stephenfin/dotfiles

If you 'Cc' me in any patches you write, I'd be happy to review them (I
don't monitor the OVS ML actively otherwise).

Hope this helps,
Stephen