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.
Starting from Linux 4.11, IPv6 ECMP routes are now notified using
RTA_MULTIPATH, like IPv4 ones. The patch adds support for RTA_MULTIPATH
parsing for IPv6 routes. This also enables to parse ECMP alien routes
correctly.
Thanks to Vincent Bernat for the original patch.
Add a new route attribute, krt_scope, to expose the Linux kernel route
scope. Constants from /etc/iproute2/rt_scopes (prefixed by "ips_") are
expected to be used with the attribute. Both import and export are
supported.
Also, the patch fixes device route export to the kernel, by setting link
scope automatically.
Kernel routes with different metrics do not clash with each other,
therefore using dedicated metric value is a reliable way to avoid
overwriting routes from other sources (e.g. kernel device routes).
Although kernel route metric could already be set as a route attribute by
filters, that is not consistent with the way how Linux kernel handles
route metric - not just a route attribute, but a part of a route key.
Linux represents IPv6 ECMP routes as a sequence of unipath routes with
the same prefix. We have to translate between our representation (one
route with multipath next hop) and the Linux representation in both
directions.
Proper learning of alien IPv6 ECMP routes still not supported.
Thanks to Mikhail Sennikovskii for the original patch.
Ignore tentative IPv6 addresses and wait until finish of Duplicate
Address Detection (We got notification when an address is no longer
tentative) to avoid problems when protocols try to use interfaces
with tentative link-local addresses.
Based on patch from Jan Moskyto Matejka
The netlink code assumes an order for the members of struct msghdr.
This breaks recvmsg and sendmsg with musl libc on mips64. Fix this by
using designated initializers instead.
Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
When a kernel route changed, function krt_learn_scan() noticed that and
replaced the route in internal kernel FIB, but after that, function
krt_learn_prune() failed to propagate the new route to the nest, because
it confused the new route with the (removed) old best route and decided
that the best route did not changed.
Wow, the original code (and the bug) is almost 17 years old.
Wanted netlink attributes are defined in a table, specifying
their size and neediness. Removing the long conditions that did the
validation before.
Also parsing IPv4 and IPv6 versions regardless on the IPV6 macro.
Since 2.6.19, the netlink API defines RTA_TABLE routing attribute to
allow 32-bit routing table IDs. Using this attribute to index routing
tables at Linux, instead of 8-bit rtm_table field.
Unfortunately, some interfaces support multicast but do not have
this flag set, so we use it only as a positive hint.
Thanks to Clint Armstrong for noticing the problem.
Allows to send and receive multiple routes for one network by one BGP
session. Also contains necessary core changes to support this (routing
tables accepting several routes for one network from one protocol).
It needs some more cleanup before merging to the master branch.
