Resolve neighbors using longest prefix match. Although interface ranges
should not generally collide, it may happen for unnumbered links.

Thanks to Kenth Eriksson for the bugreport.

This is merely a const propagation. There was no problem in there.

Protocol can have specified VRF, in such case it is restricted to a set
of ifaces associated with the VRF, otherwise it can use all interfaces.

The patch allows to specify VRF as 'default', in which case it is
restricted to a set of iface not associated with any VRF.

Modify protocols to use preferred address change notification instead on
depending on hard-reset of interfaces in that case, and remove hard-reset
in that case. This avoids issue when e.g. IPv6 protocol restarts
interface when IPv4 preferred address changed (as hard-reset is
unavoidable and common for whole iface).

The patch also fixes a bug when removing last address does not send
preferred address change notification.

Allow to change an interface associated with a route by setting
ifname attribute. It will also change the route to a direct one.

The command showed interfaces that were removed / in shutdown.

Also redesign preferred address selection and update protocols to use
appropriate preferred address.

Based on a previous work by Jan Maria Matejka.

Add basic VRF (virtual routing and forwarding) support. Protocols can be
associated with VRFs, such protocols will be restricted to interfaces
assigned to the VRF (as reported by Linux kernel) and will use sockets
bound to the VRF. E.g., different multihop BGP instances can use diffent
kernel routing tables to handle BGP TCP connections.

The VRF support is preliminary, currently there are several limitations:

- Recent Linux kernels (4.11) do not handle correctly sockets bound
to interaces that are part of VRF, so most protocols other than multihop
BGP do not work. This will be fixed by future kernel versions.

- Neighbor cache ignores VRFs. Breaks config with the same prefix on
local interfaces in different VRFs. Not much problem as single hop
protocols do not work anyways.

- Olock code ignores VRFs. Breaks config with multiple BGP peers with the
same IP address in different VRFs.

- Incoming BGP connections are not dispatched according to VRFs.
Breaks config with multiple BGP peers with the same IP address in
different VRFs. Perhaps we would need some kernel API to read VRF of
incoming connection? Or probably use multiple listening sockets in
int-new branch.

- We should handle master VRF interface up/down events and perhaps
disable associated protocols when VRF goes down. Or at least disable
associated interfaces.

- Also we should check if the master iface is really VRF iface and
not some other kind of master iface.

- BFD session request dispatch should be aware of VRFs.

- Perhaps kernel protocol should read default kernel table ID from VRF
iface so it is not necessary to configure it.

- Perhaps we should have per-VRF default table.

non-primary is ugly, just omit it (and use primary in the other case).

A non-primary address isn't necessarily secondary, that's an independent
flag.

Jan Moskyto Matejka authored 8 years ago and Ondřej Zajíček committed 8 years ago

There are several unresolved -Wmissing-field-initializers on older
versions of GCC than 5.1, all of them false positive.

The patch adds support for channels, structures connecting protocols and
tables and handling most interactions between them. The documentation is
missing yet.

Jan Moskyto Matejka authored 9 years ago and Ondřej Zajíček committed 9 years ago

Minor changes by Ondrej Santiago Zajicek

Use net_addr for interface address prefixes, support net_addr in
configuration parser.

Now the order is:

Up   -> iface, addr, neigh
Down -> neigh, addr, iface

It fixes the case when an iface appears, related static routes are
activated and exported to OSPF before the iface notification and
therefore forwarding addresses are not encoded in generated external
LSAs.

Thanks to Alexander V. Chernikov for the patch.

Router ID could be automatically determined based of subset of
ifaces/addresses specified by 'router id from' option. The patch also
does some minor changes related to router ID reconfiguration.

Thanks to Alexander V. Chernikov for most of the work.

Thanks to Alexander V. Chernikov for original patch.

Iface flags are not updated in some cases.

Allows using NEF_STICKY neighbors with link-local addresses. This is
used for static route nexthops, they can be specified like fe80::1%eth0
.

Thanks Matthias Schiffer for the bugreport and the original patch.

Mainly changes IA_UNNUMBERED to IA_PEER and adds IA_HOST. Also do not
show broadcast addr in show interfaces. Nobody cares for that.

Also changes some symbol names (IFF_ADMIN_DOWN -> IFF_SHUTDOWN,
IFF_LINK_UP -> IFF_ADMIN_UP).

When device protocol goes down, interfaces should be flushed
asynchronously (in the same way like routes from protocols are flushed),
when protocol goes to DOWN/HUNGRY.

This fixes the problem with static routes staying in kernel routing
table after BIRD shutdown.

Allows to add more interface patterns to one common 'options'
section like:

interface "eth3", "eth4" { options common to eth3 and eth4 };

Also removes undocumented and unnecessary ability to specify
more interface patterns with different 'options' sections:

interface "eth3" { options ... }, "eth4" { options ... };

and only the highest scope one has IA_PRIMARY set, so report
the remaining ones as "Unselected".