rework mpw to be an actual ethernet interface.

this will allow for a lot of special casing in places like vlan and
bridge to go away since mpw will do all the same things as any other
ethernet tunnel. another benefit is you can run stuff directly on
the mpw interface to interact with the pseudowire, rather than
requiring a bridge and vether interface. this is like what juniper
calls Pseudowire Service Interfaces.

the caveat is that the implicit vlan or svlan tagging that mpw did
in ethernet-tagged mode now has to be done by hand. however, there
is some indication that different vendors pick different types of
tags, ie, one uses vlan tags and another uses svlan, so being able
to configure the right one has value. it is also possible you would
want to bridge the entire tag stack to another site, so being able
to bridge mpw without it playing with the tags can be useful.

because the if_type on mpw changes from IFT_MPLSTUNNEL to IFT_ETHER,
the semantic used to handle incoming packets in mpls_input is
changed. instead of mpls_input pushing the packets into mpw based
on the if_type being IFT_MPLSTUNNEL, mpw now adds an RTF_LOCAL route
to the mpls table. mpls_input falls through to "outputting" the
packet to mpw_output, which then uses the RTF_LOCAL flag to decide
to input to mpw_input and then ether_input. this semantic will be
applied to mpe soon, which removes all the interface special casing
in mpls_input. the if_type change also means mpw implements the
SIOCGPWE3 ioctl so ldpd can still figure out that the interface is
a pseudowire.

ok claudio@

0 files changed, 0 insertions, 0 deletions