The restart timer was racy and didn't allow for immediate restarts
from limits. Now the protocols stores the last restart time and in case
of too frequent autorestarts caused by exceeded limits, the protocol
gets disabled with an error message.
Also now there is a configuration knob for this.
There were some nasty problems with deferred protocol state updates and
race conditions on BGP startup, shutdown, and also with referencing the
cached states.
Now it looks fixed.
To allow reading of protocol states from other protocols or completely
different routines, we have to export these states to data structures
not requiring to lock the protocol loops.
On one hand, this doesn't give the reader the actual state "right now",
on the other hand, getting that is impossible in a properly
multithreaded environment and you will always get the information with
some (little but noteworthy) delay.
This implementation handles only the basic state information of the
protocols, common for all the protocols. Adding protocol-specific state
information should be done by implementing the protocol hook init_state().
Channel information is stored but not announced, as we don't need the
announcements for now.
For the upcoming rework of protocol state information propagation,
we need some more eattr types to be defined.
These types are probably not defined completely and before using
them for route attributes, you should check that they don't lack
some crucial methods.
RPKI-To-Router (RTR) sessions seem to be similar security-sensitivity as
IBGP sessions. BIRD already offered a choice of either "plain TCP" (meh)
or "SSH" (secure, albeit a bit more hassle to set up than TCP-MD5).
The patch adds TCP-MD5 as another option. TCP-MD5 for RTR is specified
through RFC 6810 section 7.3 and RFC 8210 section 9.3.
Minor changes by committer.
Before this commit, on kernel shutdown, the routes were re-exported by
the regular export but treated as withdraw. This was too hairy and
caused unnecessary complexity of the protocol's state machine.
Instead of that, we found out that it makes more sense to just refeed
the routes synchronously and convert to withdraw. This is done by the
direct export access instead of the channel.
It would (maybe) make more sense to run export filters on this in case
the export filter updates the krt_metric attribute, but as this doesn't
work on regular withdraw anyway, it's better for now to just let it be
and maybe somebody in the future fixes this issue.
Introduced in 08ff0af898, the additional CLI
configuration wasn't properly initialized in the parse-and-exit mode
due to an oversight that cli_init_unix() is not called in this mode.
Thanks to Felix Friedlander for the bugreport.
The period of recurent timers was stored in 32b field, despite it was
btime-compatible value in us. Therefore, it was limited to ~72 min,
which mas okay for most purposes, except configurable MRT dump periods.
Thanks to Felix Friedlander for the bugreport.
The socket structure has the field rbsize (receive buffer size), which
controls the size of the userspace receive buffer. There is also kernel
receive buffer, which in some cases may be smaller (e.g. on FreeBSD it
is by default ~8k). The patch ensures that the kernel receive buffer is
as large as the userspace receive buffer.
When VRFs are used, BIRD correctly binds listening (and connecting)
sockets to their VRFs but also re-binds accepted sockets to the same VRF.
This is not needed as the interface bind is inherited in this case, and
indeed this redundant bind causes an -EPERM if BIRD is running as
non-root making BIRD close the connection and reject the peer.
Thanks to Christian Svensson for the original patch and Alexander Zubkov
for suggestions.
