There are three common ways how to encode IPv6 link-local-only next hops:
(:: ll), (ll), and (ll ll). We use the first one but we should accept all
three. The patch fixes handling of the last one.
Thanks to Sebastian Hahn for the bugreport.
The RFC 5575 does not explicitly reject flowspec rules without dst part,
it just requires dst part in validation procedure for feasibility, which
we do not implement anyway. Thus flow without dst prefix is syntactically
valid, but unfeasible (if feasibilty testing is done).
Thanks to Alex D. for the bugreport.
When dynamic BGP with remote range is configured, MD5SIG needs to use
newer socket option (TCP_MD5SIG_EXT) to specify remote addres range for
listening socket.
Thanks to Adam Kułagowski for the suggestion.
During NLRI parsing of IPv6 Flowspec, dst prefix was not properly
extracted from NLRI, therefore a received flow was stored in a different
position in flowspec routing table, and was not reachable by command
'show route <flow>'.
Add proper prefix part accessors to flowspec code and use them from BGP
NLRI parsing code.
Thanks to Alex D. for the bugreport.
This is optional check described in RFC 4271. Although this can be also
done by filters, it is widely implemented option in BGP implementations.
Thanks to Eugene Bogomazov for the original patch.
Transitive extended communities should be removed on external sessions,
the old code them in all cases.
Thanks to Jean-Daniel Pauget for the original patch.
Change of some options requires route refresh, but when import table is
active, channel reload is done from it instead of doing full route
refresh. So in this case we request it internally.
There is an improper check for valid message size, which may lead to
stack overflow and buffer leaks to log when a large message is received.
Thanks to Daniel McCarney for bugreport and analysis.
Instead of having large stack buffer for max amount of AFI/SAFI pairs.
The old code is not correct w.r.t. extendeded option length, as more
AFI/SAFI pairs may fit into the capability option.
The patch implements optional internal export table to a channel and
hooks it to BGP so it can be used as Adj-RIB-Out. When enabled, all
exported (post-filtered) routes are stored there. An export table can be
examined using e.g. 'show route export table bgp1.ipv4'.
Several BGP channel options (including 'next hop self') could be
reconfigured without session reset, with just route refeed/refresh.
The patch improves reconfiguration code to do it that way.
The 'deterministic med' option is implemented by suppressing other than
best-in-group routes (grouped by ASN) from best route selection. This
interferes with 'merge paths' as supressed routes are no longer mergable
with best route. This is fixed by suppressing only those routes that are
not mergable with best-in-group route.
If BGP has too many data to send and BIRD is slower than the link, TX is
always possible until all data is sent. This patch limits maximum number
of generated BGP messages in one iteration of TX hook.
When 'graceful down' command is entered, protocols are shut down
with regard to graceful restart. Namely Kernel protocol does
not remove routes and BGP protocol does not send notification,
just closes the connection.
Useful for implementation of agents implementing the SNMP-BGP MIB, which
requires the local AS of a session to be specified.
Thanks to Jan-Philipp Litza for the patch.
Support for dynamically spawning BGP protocols for incoming connections.
Use 'neighbor range' to specify range of valid neighbor addresses, then
incoming connections from these addresses spawn new BGP instances.
When BGP connection is opened, it may happen that rx hook (with remote
OPEN) is called before tx hook (for local OPEN). Therefore, we need to do
internal changes (like setting local_caps) synchronously with OPENSENT
transition and we need to ensure that OPEN is sent before KEEPALIVE.
Allow to specify just 'internal' or 'external' for remote neighbor
instead of specific ASN. In the second case that means BGP peers with
any non-local ASNs are accepted.
This is a major change of how the filters are interpreted. If everything
works how it should, it should not affect you unless you are hacking the
filters themselves.
Anyway, this change should make a huge improvement in the filter performance
as previous benchmarks showed that our major problem lies in the
recursion itself.
There are also some changes in nest and protocols, related mostly to
spreading const declarations throughout the whole BIRD and also to
refactored dynamic attribute definitions. The need of these came up
during the whole work and it is too difficult to split out these
not-so-related changes.
Since v2 we have multiple listening BGP sockets, and each BGP protocol
has associated one of them. Use listening socket that accepted the
incoming connection as a key in the dispatch process so only BGP
protocols assocaited with that listening socket can be selected.
This is necesary for proper dispatch when VRFs are used.
Extend 'next hop keep' and 'next hop self' options to have boolean values
(enabled / disabled) and also values 'ibgp'/ 'ebgp' to restrict it to
routes received from IBGP / EBGP. This allows to have it enabled by
default in some cases, matches features of other implementations, and
allows to handle some strange cases like EBGP border router with 'next
hop self' also doing IBGP route reflecting.
Change default of 'next hop keep' to enabled for route servers, and
'ibgp' for route reflectors.
Update documentation for these options.
When route is exported to regular EBGP, local ASN should be prepended to
AS_PATH. When route is propagated by route server (between RS-marked
EBGP peers), it should not change AS_PATH. Question is what to do in
other cases (from non-RS EBGP, IBGP, or locally originated to RS EBGP).
In 1.6.x, we did not prepend ASN in non-RS EBGP or IBGP to RS EBGP, but
we prepended in local to RS EBGP.
In 2.0.x, we changed that so only RS-EBGP to RS-EBGP is not prepended.
We received some negative responses (thanks to heisenbug and Alexander
Zubkov), we decided to change it back. One reason is that it is simple
to modify the AS_PATH by filters, but not possible to un-modify
changes done by BGP itself. Also, as 1.6.x behavior was not really
consistent, the final behavior is that ASN is never prepended when
exported to RS EBGP, like to IBGP.
Note that i do not express an opinion about whether such configurations
are even reasonable.
