This is a reimplementation of commit 0f2be469f8
by Alexander Zubkov. In the master branch, changes in commit eb937358
broke setting of channel preference for alien routes learned during
scan. The preference was set only for async routes.
The original solution is extended here to accomodate for v3 specifics.
Routes are now allocated only when they are just to be inserted to the
table. Updating a route needs a locally allocated route structure.
Ownership of the attributes is also now not transfered from protocols to
tables and vice versa but just borrowed which should be easier to handle
in a multithreaded environment.
We can also quite simply allocate bigger blocks. Anyway, we need these
blocks to be aligned to their size which needs one mmap() two times
bigger and then two munmap()s returning the unaligned parts.
The user can specify -B <N> on startup when <N> is the exponent of 2,
setting the block size to 2^N. On most systems, N is 12, anyway if you
know that your configuration is going to eat gigabytes of RAM, you are
almost forced to raise your block size as you may easily get into memory
fragmentation issues or you have to raise your maximum mapping count,
e.g. "sysctl vm.max_map_count=(number)".
Add a wrapper function in sysdep to get random bytes, and required checks
in configure.ac to select how to do it. The configure script tries, in
order, getrandom(), getentropy() and reading from /dev/urandom.
From now, there are no auxiliary pointers stored in the free slab nodes.
This led to strange debugging problems if use-after-free happened in
slab-allocated structures, especially if the structure's first member is
a next pointer.
This also reduces the memory needed by 1 pointer per allocated object.
OTOH, we now rely on pages being aligned to their size's multiple, which
is quite common anyway.
In general, events are code handling some some condition, which is
scheduled when such condition happened and executed independently from
I/O loop. Work-events are a subgroup of events that are scheduled
repeatedly until some (often significant) work is done (e.g. feeding
routes to protocol). All scheduled events are executed during each
I/O loop iteration.
Separate work-events from regular events to a separate queue and
rate limit their execution to a fixed number per I/O loop iteration.
That should prevent excess latency when many work-events are
scheduled at one time (e.g. simultaneous reload of many BGP sessions).
This is an implementation of draft-walton-bgp-hostname-capability-02.
It is implemented since quite some time for FRR and in datacenter, this
gives a nice output to avoid using IP addresses.
It is disabled by default. The hostname is retrieved from uname(2) and
can be overriden with "hostname" option. The domain name is never set
nor displayed.
Minor changes by committer.
So one can define kernel protocol template without channels.
For other protocols, it is either irrelevant or already done.
Thanks to Clemens Schrimpe for the bugreport.
The log subsystem should be locked earlier, as default_log_list() may
internally manipulate with the current_log_list (if it is also a default
log list).
The static logging structures are reused, we need to reinitialize them
otherwise add_tail() would fail in debug build. Reinitializing these
structures should be fine as the list they belong to is being
reinitialized on entry to the very same function.
Thanks to Andreas Rammhold and Mikael Magnusson for patches.
This is a quick workaround for an issue where configured logfiles are
opened/created during parsing of a config file even when parse-and-exit
option is active. We should later refactor the logging code to avoid
opening log during parsing altogether.
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.
The old code stored route verdicts and temporary routes directly in
rtable. The new code do not store received routes (it immediately
compares them with exported routes and resolves conflicts) and uses
internal bitmap to keep track of which routes were received and which
needs to be reinstalled.
By not putting 'invalid' temporary routes to rtable, we keep rtable
in consistent state, therefore scan no longer needs to be atomic
operation and could be splitted to multiple events.
Use a hierarchical bitmap in a routing table to assign ids to routes, and
then use bitmaps (indexed by route id) in channels to keep track whether
routes were exported. This avoids unreliable and inefficient re-evaluation
of filters for old routes in order to determine whether they were exported.
Names read from texfiles in /etc/iproute2/* are normalized by replacing
non-alphanumeric chars with underscore. The patch fixes handling of
uppercase letters, which were handled as non-alphanumberic.
Thanks to Igor Gavrilov for the bugreport.
The C11 specification allows only sig_atomic_t and _Atomic variable
access. All other accesses to global variables are undefined behavior.
Using int was probably OK on x86 and x86_64; yet there were some reports
from other architectures (especially some MIPS) that in rare cases,
after issuing SIGHUP, BIRD did strange things.
The command initiating planned graceful restart including bird shutdown
should be called 'graceful restart' instead of 'graceful down', as the
later should be reserved for graceful shutdown in style of RFC 8326.
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.
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.
