In order to provide Link State Traffic Engineering features to IS-IS, this
patch adds some modifications to base IS-IS:
- Solve bug in lsp iterate function to avoid infinite loop in isis_lsp.c by
adding condition to recurse call
- Add new trigger event to parse LSP in isis_lsp.c
- Add new TE debug flag to track Traffic Engineering events in isisd.[c,h]
- Correct small bug in isis_tlvs.c where delay and min/max delay are not
correctly handle
- Handle Opaque LSA Traffic Engineering Zebra API in isis_zebra.[c,h]
Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>
Currently, we have a lot of checks in CLI and NB layer to prevent
incompatible IS-types of circuits and areas. All these checks become
completely meaningless when the interface is moved between VRFs. If the
area IS-type is different in the new VRF, previously done checks mean
nothing and we still end up with incorrect circuit IS type. To actually
prevent incorrect IS type, all checks must be done in the processing
code.
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
The problem is related to startup configuration, which is not operational
on default vrf name.
To reproduce the issue, run the two daemons:
zebra -o vrf0 &
isisd -f /tmp/isisd.conf
router isis 1
lsp-gen-interval 2
net 10.0000.0000.0000.0000.0000.0000.0000.0000.0000.00
metric-style wide
redistribute ipv4 connected level-2
redistribute ipv6 connected level-2
The obtained show running-config looks like below:
router isis 1 vrf default
lsp-gen-interval 2
net 10.0000.0000.0000.0000.0000.0000.0000.0000.0000.00
metric-style wide
redistribute ipv4 connected level-2
redistribute ipv6 connected level-2
The default vrf name is obtained by zebra daemon. While isis is not
connected to zebra, i.e. at startup, when loading a startup configuration,
the macro VRF_DEFAULT_NAME is used and returns 'default'.
But because zebra connected and forces to a new default vrf name, the
configuration is not seen as the default one, and further attempts to
configure the isis instance via 'router isis 1' will trigger creation
of an other instance.
To handle this situation, at vrf_enable() event, which is called for
each default vrf name change, the associated isis instance is updated
with th new vrf name. The same is done for NB yang path.
Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
There is a possibility that the same line can be matched as a command in
some node and its parent node. In this case, when reading the config,
this line is always executed as a command of the child node.
For example, with the following config:
```
router ospf
network 193.168.0.0/16 area 0
!
mpls ldp
discovery hello interval 111
!
```
Line `mpls ldp` is processed as command `mpls ldp-sync` inside the
`router ospf` node. This leads to a complete loss of `mpls ldp` node
configuration.
To eliminate this issue and all possible similar issues, let's print an
explicit "exit" at the end of every node config.
This commit also changes indentation for a couple of existing exit
commands so that all existing commands are on the same level as their
corresponding node-entering commands.
Fixes#9206.
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
There are two problems with the current code for processing the attached
bit:
- we should process it when acting both a level-1-only and level-1-2
- we should add the default route when we don't have L2 adjacensies, not
when we don't have other routers configured on the device
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
We are passing around the system id using the variable name
of `argv`. Let's name the variable correctly and pass it around
correctly named.
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
in lsp_for_arg we have already checked for NULL and returned
if argv is null. We do not need to check for it again.
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
If we have the following configuration:
```
vrf red
smth
exit-vrf
!
interface red vrf red
smth
```
And we delete the VRF using "no vrf red" command, we end up with:
```
interface red
smth
```
Interface config is preserved but moved to the default VRF.
This is not an expected behavior. We should remove the interface config
when the VRF is deleted.
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
When creating a new area, we're adding all circuits in the same VRF to
this area. We should only add circuits configured with the same tag.
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
Currently, the dynamic hostname cache is global. It is incorrect because
neighbors in different VRFs may have the same system ID and different
hostnames.
This also fixes a memory leak - when the instance is deleted, the cache
must be cleaned up and the cleanup thread must be cancelled.
Fixes#8832.
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
We only need an instance when we have at least one area configured in a
VRF. Currently we have the following issues:
- instance for the default VRF is always created
- instance is not removed after the last area config is removed
This commit fixes both issues.
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
When the redistribution is configured in non-default VRF, isisd should
redistribute routes from this VRF instead of default.
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
When enabling 'debug isis lfa', the option was correctly enabled
but not displayed by 'show debugging' command.
Signed-off-by: Fredi Raspall <fredi@voltanet.io>
Currently we don't allow to configure the interface before the area is
configured. This approach has the following issues:
1. The area config can be deleted even when we have an interface config
relying on it. The code is not ready for that - we'll have a whole
bunch of stale pointers if user does that.
2. The code doesn't correctly process the event of changing the VRF for
an interface. There is no mechanism to ensure that the area exists
in the new VRF so currently the circuit still stays in the old VRF.
This commit allows an arbitrary order of area/interface configuration.
There is no more need to configure the area before configuring the
interface.
This change fixes both the issues.
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
Convert most DEFINE_MTYPE into the _STATIC variant, and move the
remaining non-static ones to appropriate places.
Signed-off-by: David Lamparter <equinox@diac24.net>
Add support for read only mib objects from RFC4444.
Signed-off-by: Lynne Morrison <lynne@voltanet.io>
Signed-off-by: Karen Schoener <karen@voltanet.io>
When adjacencies change state the attached-bits in LSPs in other areas
on the router may need to be modified.
1. If a router no longer has a L2 adjacency to another area the
attached-bit must no longer be sent in the LSP
2. If a new L2 adjacency comes up in a different area then the
attached-bit should be sent in the LSP
Signed-off-by: Lynne Morrison <lynne@voltanet.io>
The purpose of the Attach-bit is to accomplish inter-area routing. In other
venders, the Attached-bit is automatically set when a router is configured
as a L1|L2 router and has two adjacencies. When a L1 router receives a LSP
with the Attached-bit set it is supposed to create a default route pointing
toward the neighbor to provide a default path out of the L1 area.
ISIS implementation has been fixed to support the above definition:
Setting the Attach-bit is now the default behavior and we allow the user to
turn it off.
We will only set the Default Attach-bit when creating a L1 LSP, if we are
a L1|L2 router and have a L2 adjacency up.
When a L1 router receives a LSP with the Attach-bit set, we will create a
default route pointing to the L1|L2 router as the nexthop.
The default route will be removed if the LSP is received with the Attach-bit
cleared.
Signed-off-by: Lynne Morrison <lynne@voltanet.io>
Remote LFA (RFC 7490) is an extension to the base LFA mechanism
that uses dynamically determined tunnels to extend the IP-FRR
protection coverage.
RLFA is similar to TI-LFA in that it computes a post-convergence
SPT (with the protected interface pruned from the network topology)
and the P/Q spaces based on that SPT. There are a few differences
however:
* RLFAs can push at most one label, so the P/Q spaces need to
intersect otherwise the destination can't be protected (the
protection coverage is topology dependent).
* isisd needs to interface with ldpd to obtain the labels it needs to
create a tunnel to the PQ node. That interaction needs to be done
asynchronously to prevent blocking the daemon for too long. With
TI-LFA all required labels are already available in the LSPDB.
RLFA and TI-LFA have more similarities than differences though,
and thanks to that both features share a lot of code.
Limitations:
* Only RLFA link protection is implemented. The algorithm used
to find node-protecting RLFAs (RFC 8102) is too CPU intensive and
doesn't always work. Most vendors implement RLFA link protection
only.
* RFC 7490 says it should be a local matter whether the repair path
selection policy favors LFA repairs over RLFA repairs. It might be
desirable, for instance, to prefer RLFAs that satisfy the downstream
condition over LFAs that don't. In this implementation, however,
RLFAs are only computed for destinations that can't be protected
by local LFAs.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
Rename "debug isis ti-lfa" to "debug isis lfa". Having different
debug guards for different kinds of LFA (classic, remote and TI-LFA)
doesn't make sense since all LFA solutions share code to certain
extent.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
On redistribution into isis we were creating a table for
handling the redistributed routes, but never cleaning them
up on shutdown properly. Do so.
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
When isis is being shutdown the area->spf_timer thread has
special data assigned to that was never being freed.
Free this data.
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
Replace all lib/thread cancel macros, use thread_cancel()
everywhere. Only the THREAD_OFF macro and thread_cancel() api are
supported. Also adjust thread_cancel_async() to NULL caller's pointer (if
present).
Signed-off-by: Mark Stapp <mjs@voltanet.io>
==935465== 40 bytes in 1 blocks are definitely lost in loss record 71 of 546
==935465== at 0x483AB65: calloc (vg_replace_malloc.c:760)
==935465== by 0x48D6611: qcalloc (memory.c:110)
==935465== by 0x48CFE02: list_new (linklist.c:32)
==935465== by 0x15DBF0: isis_new (isisd.c:213)
==935465== by 0x15DAC4: isis_global_instance_create (isisd.c:179)
==935465== by 0x121892: main (isis_main.c:264)
==935465== 64 (40 direct, 24 indirect) bytes in 1 blocks are definitely lost in loss record 101 of 546
==935465== at 0x483AB65: calloc (vg_replace_malloc.c:760)
==935465== by 0x48D6611: qcalloc (memory.c:110)
==935465== by 0x48CFE02: list_new (linklist.c:32)
==935465== by 0x15DBE3: isis_new (isisd.c:212)
==935465== by 0x15DAC4: isis_global_instance_create (isisd.c:179)
==935465== by 0x121892: main (isis_main.c:264)
On isis shutdown we are seeing the above memory leaks. Modify
the code to start cleaning this up.
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
TI-LFA is a modern fast-reroute (FRR) solution that leverages Segment
Routing to pre-compute backup nexthops for all destinations in the
network, helping to reduce traffic restoration times whenever a
failure occurs. The backup nexthops are expected to be installed
in the FIB so that they can be activated as soon as a failure
is detected, making sub-50ms recovery possible (assuming an
hierarchical FIB).
TI-LFA is a huge step forward compared to prior IP-FRR solutions,
like classic LFA and Remote LFA, as it guarantees 100% coverage
for all destinations. This is possible thanks to the source routing
capabilities of SR, which allows the backup nexthops to steer traffic
around the failures (using as many SIDs as necessary). In addition
to that, the repair paths always follow the post-convergence SPF
tree, which prevents transient congestions and suboptimal routing
from happening.
Deploying TI-LFA is very simple as it only requires a single
configuration command for each interface that needs to be protected
(both link protection and node protection are available). In addition
to IPv4 and IPv6 routes, SR Prefix-SIDs and Adj-SIDs are also
protected by the backup nexthops computed by the TI-LFA algorithms.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
1. Added isis with different vrf and it's dependecies.
2. Added new vrf leaf in yang.
3. A minor change for IF_DOWN_FROM_Z passing argrument is
replaced with ifp pointer in api "isis_if_delete_hook()".
4. Minor fix in the isisd spf unit test.
Co-authored-by: Kaushik <kaushik@niralnetworks.com>"
Signed-off-by: harios_niral <hari@niralnetworks.com>
Now that the IS-IS SPF code is more modular, write some unit tests
for it.
This commit includes a new test program called "test_isis_spf" which
can load any test topology (there are 13 different ones available)
and run SPF on any desired node. In the future this same test program
and topologies will also be used to test reverse SPF and TI-LFA.
The "test_common.c" file contains helper functions used to parse the
topology descriptions from "test_topologies.c" into LSP databases
that can be used as an input to the SPF code.
This commit also introduces the F_ISIS_UNIT_TEST flag which is used
to prevent the IS-IS code from scheduling any event when running
under the context of an unit test.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
The goal of modularizing the SPF code is to make it possible for
isisd to run SPF in the behalf of other nodes in the network, which
is going to be necessary later when implementing the R-LFA/TI-LFA
solutions. On top of that, a modularized SPF opens the door for
much needed unit testing.
Summary of the changes:
* Change the isis_spf_preload_tent() function to use the local LSP
as an input (as per the ISO specification) instead of populating
the TENT based on the list of local interfaces;
* Introduce the "isis_spf_adj" structure to represent an SPF
adjacency. SPF adjacencies are inferred from the LSPDB, different
from normal adjacencies formed using IIH messages;
* Introduce the F_SPFTREE_NO_ROUTES flag to control whether the
SPT should create routes or not;
* Introduce the F_SPFTREE_NO_ADJACENCIES flag to specify whether
IS-IS adjacency information is available or not. When running SPF
in the behalf of other nodes, or under the context of an unit test,
no adjacency information will be present.
* On isis_area_create(), move some code around so that the area's isis
backpointer is set as early as possible.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
* Bring back some consts that were removed;
* Replace ALL_LIST_ELEMENTS by ALL_LIST_ELEMENTS_RO whenever
possible;
* Fix some CLI return values;
* Remove some unnecessary initializations.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
1. Created a structure "isis master".
2. All the changes are related to handle ISIS with different vrf.
3. A new variable added in structure "isis" to store the vrf name.
4. The display commands for isis is changed to support different VRFs.
Signed-off-by: Kaushik <kaushik@niralnetworks.com>
This should simplify all code that needs to iterate over all
adjacencies of a given area (iterating over all adjacencies of all
circuits is cumbersome).
While here, repurpose isis_adj_exists() into a lookup function,
making it more generally useful.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
The global isis structure can't be created/destroyed using the CLI,
so there's no need to define a QOBJ for it.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
Make that function accept an IS-IS area pointer instead of an
area name, making it more in line with the rest of the code base
(*delete() functions shouldn't perform lookups internally).
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
Some commands were using IS-IS while others were using ISIS. Fix
this inconsistency (prefer the former option for obvious reasons).
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
This fixes a problem where "show isis summary" could display
inconsistent information about the IPv6 dst-src SPT when
"ipv6-dstsrc" wasn't explicitly configured.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
Unfortunately as the topotests show a fast recovery after failure
detection due to BFD is currently not possible because of the following
issue:
There are multiple scheduling mechanisms within isisd to prevent
overload situations. Regarding our problem these two are important:
* scheduler for regenerating ISIS Link State PDUs scheduler for managing
* consecutive SPF calculations
In fact both schedulers are coupled, the first one triggers the second
one, which again is triggered by isis_adj_state_change (which again is
triggered by a BFD 'down' message). The re-calculation of SPF paths
finally triggers updates in zebra for the RIB.
Both schedulers work as a throttle, e.g. they allow the regeneration of
Link State PDUs or a re-calculation for SPF paths only once within a
certain time interval which is configurable (and by default different!).
This means that a request can go through the first scheduler but might
still be 'stuck' at the second one for a while. Or a request can be
'stuck' at the first scheduler even though the second one is ready. This
also explains the 'random' behaviour one can observe testing since a
'fast' recovery is only possible if both schedulers are ready to process
this request.
Note that the solution in this commit is 'thread safe' in the sense that
both schedulers use the same thread master such that the introduced
flags are only used exactly one time (and one after another) for a
'fast' execution.
Further there are some irritating comments and logs which I partially
removed. They seems to be not valid anymore due to changes in thread
management (or they were never valid in the first place).
Signed-off-by: GalaxyGorilla <sascha@netdef.org>
This is an implementation of the IS-IS SR draft [1] for FRR.
The following features are supported:
* IPv4 and IPv6 Prefix-SIDs;
* IPv4 and IPv6 Adj-SIDs and LAN-Adj-SIDs;
* Index and absolute labels;
* The no-php and explicit-null Prefix-SID flags;
* Full integration with the Label Manager.
Known limitations:
* No support for Anycast-SIDs;
* No support for the SID/Label Binding TLV (required for LDP interop).
* No support for persistent Adj-SIDs;
* No support for multiple SRGBs.
[1] draft-ietf-isis-segment-routing-extensions-25
Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
isisd implements an optimization that allows multiple routes to
share the same nexthop (using a refcount) in order to save memory.
Now that SR support is coming, however, it will be necessary to
embed additional SR-related information inside the isis_nexthop
structure. But this can only be done if the nexthops aren't shared
among routes anymore.
Removing this memory optimization should have minimal impact since
the isis_nexthop structure is really small. On large networks with
thousands of routes, the memory saving would be in the order of a
few kilobytes. Not something we should be concerned about nowadays.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
When we call isis_adj_state_change with ISIS_ADJ_DOWN
we free the pointer, but we were still using the pointer
after it was freed. Cleanup the api to prevent this.
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
And again for the name. Why on earth would we centralize this, just so
people can forget to update it?
Signed-off-by: David Lamparter <equinox@diac24.net>
Same as before, instead of shoving this into a big central list we can
just put the parent node in cmd_node.
Signed-off-by: David Lamparter <equinox@diac24.net>
There is really no reason to not put this in the cmd_node.
And while we're add it, rename from pointless ".func" to ".config_write".
[v2: fix forgotten ldpd config_write]
Signed-off-by: David Lamparter <equinox@diac24.net>
The only nodes that have this as 0 don't have a "->func" anyway, so the
entire thing is really just pointless.
Signed-off-by: David Lamparter <equinox@diac24.net>
Yang constraints enforced by the northbound callbacks require that
the maximum lifetime be >= than (refresh interval + 300). When we are
moving from one config to another through frr-reload.py, we issue
a number of vtysh -c commands ('no lsp-refresh-interval level-1 500',
'no max-lsp-lifetime level-1 1000'), which reset these parameters to their
default values, respectively 900 and 1200. Depending on the actual
values in the current config, the order in which these commands are sent
might be the wrong one, in that we hit an invalid intermediate state and
make vtysh (and by extension frr-reload.py) return an error.
As a workaround, let's add a one-liner command that sets all these
inter-related parameters in one go, and make isisd display them as a
single line too, so that the diff will be computed as a single command.
The old individual commands are kept to ensure backwards compatibility.
Signed-off-by: Emanuele Di Pascale <emanuele@voltanet.io>
Currently isisd has this strange (legacy) behavior where the
first area is created by default with level-1-2, while every
other subsequent area uses the default defined in the yang model,
which is level-1. This is a source of confusion when trying to
configure the daemon programatically, either with frr-reload
or using the transactional cli. Given how rare having multiple
IS-IS instances is anyway, the easiest solution is to remove
this behavior and default to level-1-2 for every area.
Note that this does not affect fabricd, which continues using
exclusively level-2-only areas.
Signed-off-by: Emanuele Di Pascale <emanuele@voltanet.io>
Rearrange the isisd northbound callbacks as following:
* isis_nb.h: prototypes of all northbound callbacks.
* isis_nb.c: definition of all northbound callbacks and their
associated YANG data paths.
* isis_nb_config.c: implementation of YANG configuration nodes.
* isis_nb_state.c: implementation of YANG state nodes.
* isis_nb_notifications.c: implementation of YANG notifications.
This should help to keep to code more organized and easier to
maintain.
No behavior changes intended.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
This unification allows us to write code that works for both IPv4 and
IPv6, reducing duplication.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
`strcpy` is a dangerous function and should not be used. In this
particular place, there is no need for copying strings at all, so let's
just stick to referencing static strings.
Signed-off-by: Christian Franke <chris@opensourcerouting.org>
Historically, isisd has been carrying around its own red-black tree to
manage its LSP DB in. This replaces that with the newly-added
DECLARE_RBTREE_*. This allows completely removing the dict_* code.
Signed-off-by: David Lamparter <equinox@diac24.net>
Solve issue #4032
- Change MPLS-TE from global to per Area
- Add new mpls_te_area structure to area in replacement of global variable
isisMPLS_TE
- Move mpls-te from global to instance in frr-isisd.yang
- Change code in isis_te.c, isis_northbound.c, isis_cli.c, isis_pdu.c,
isis_lsp.c and isis_zebra.c accordingly
Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>
- Change MPLS-TE from global to per Area
- Add new mpls_te_area structure to area in replacement of global variable
isisMPLS_TE
- Move mpls-te frmo global to instance in frr-isisd.yang
- Change code in isis_te.c, isis_northbound.c, isis_cli.c, isis_pdu.c,
isis_lsp.c and isis_zebra.c accordingly
Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>
also fix a minor issue with isis_config_write where we were
not incrementing the write variable, which is used to append
a new line at the end of the vty string
Signed-off-by: Emanuele Di Pascale <emanuele@voltanet.io>
Note that some of the validation checks that were previously
executed in the code have been moved to the YANG model.
Signed-off-by: Emanuele Di Pascale <emanuele@voltanet.io>
This is a simple command but with a complex callback, the only
one in isisd which uses the resource allocation API implemented
in the northbound (i.e. the PREPARE phase).
Signed-off-by: Emanuele Di Pascale <emanuele@voltanet.io>
These are complex commands to retrofit, partly due to the number of
different callbacks they touch. Additionally, in FRR adding
an interface to an IS-IS area that does not exist also creates that
area. To make sure that this behavior is kept, while at the same
time keeping the northbound api consistent, we need to take extra
care to call the appropriate callbacks to update the YANG tree.
Note that many callbacks rely on the existence of the corresponding
IS-IS area; when these callbacks are joined together in a single
transaction, we need to ensure that the area creation is performed
first, or the config will fail. For this reason, the isis instance
create callback has been given a slightly lower priority than the
others.
Signed-off-by: Emanuele Di Pascale <emanuele@voltanet.io>
Finding an LSP by its id is useful not only for the
`show isis database` command.
So move it out into its own function to make it reusable.
Signed-off-by: Christian Franke <chris@opensourcerouting.org>
To allow easier debugging of LSP transmission scheduling, add a debug
mode where all tx-queue insertions/deletions are logged.
Signed-off-by: Christian Franke <chris@opensourcerouting.org>
lsp_l1_refresh and lsp_l2_refresh are identical apart from the
hardcoded IS-IS level they are referring to. So merge them and
pass the level as part of the argument.
Signed-off-by: Christian Franke <chris@opensourcerouting.org>
Implement RFC 6232, optionally allowing to flood isisd's NET and
hostname in purges it originates.
Signed-off-by: Christian Franke <chris@opensourcerouting.org>
Add a command `debug openfabric flooding` to allow verification of
correct operation of the OpenFabric flooding optimization algorithm.
Signed-off-by: Christian Franke <chris@opensourcerouting.org>
While OpenFabric calculates most tier numbers automatically by the
fabric locality calculation algorithm, that algorithm requires two
systems to be manually configured as tier 0, so it has reference points.
Also, completely manual configuration is possible.
To support this, introduce appropriate CLI commands and flood the
configured information.
Signed-off-by: Christian Franke <chris@opensourcerouting.org>
OpenFabric uses an spf with the metric for all links set to one,
both for flooding optimization and for fabric locality detection.
So extend isisd's spf code to allow running it with such a metric
and have it run whenever normal spf runs.
Signed-off-by: Christian Franke <chris@opensourcerouting.org>
OpenFabric changes IS-IS's initial database synchronization. While
regular IS-IS will simultaneuously exchange LSPs with all neighboring
routers during startup, this is considered too much churn for a densely
connected fabric.
To mitigate this, OpenFabric prescribes that a router should only
bring up an adjacency with a single neighbor and perform a full
synchronization with that neighbor, before bringing up further
adjacencies.
This is implemented by having a field `initial_sync_state` in the
fabricd datastructure which tracks whether an initial sync is still
pending, currently in progress, or complete.
When an initial sync is pending, the state will transition to the
in-progress state when the first IIH is received.
During this state, all IIHs from other routers are ignored. Any
IIHs transmitted on any link other than the one to the router with
which we are performing the initial sync will always report the far
end as DOWN in their threeway handshake state, avoiding the formation of
additional adjacencies.
The state will be left if all the SRM and SSN flags on the
initial-sync circuit are cleared (meaning that initial sync has
completed). This is checked in `lsp_tick`. When this condition occurrs,
we progress to the initial-sync-complete state, allowing other
adjacencies to form.
The state can also be left if the initial synchronization is taking too
long to succeed, for whatever reason. In that case, we fall back to the
initial-sync-pending state and will reattempt initial synchronization
with a different neighbor.
Signed-off-by: Christian Franke <chris@opensourcerouting.org>
OpenFabric specifies that it should always be run with wide metrics via
P2P links and only as Level-2. Implement this as default and remove all
the knobs from fabricd which allow other configuration.
Signed-off-by: Christian Franke <chris@opensourcerouting.org>
