Reference: https://www.cmand.org/communityexploration
--y2--
/ | \
c1 ---- x1 ---- y1 | z1
\ | /
--y3--
1. z1 announces 192.168.255.254/32 to y2, y3.
2. y2 and y3 tags this prefix at ingress with appropriate
communities 65004:2 (y2) and 65004:3 (y3).
3. x1 filters all communities at the egress to c1.
4. Shutdown the link between y1 and y2.
5. y1 will generate a BGP UPDATE message regarding the next-hop change.
6. x1 will generate a BGP UPDATE message regarding community change.
To avoid sending duplicate BGP UPDATE messages we should make sure
we send only actual route updates. In this example, x1 will skip
BGP UPDATE to c1 because the actual route is the same
(filtered communities - nothing changes).
Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com>
Implemented as per the feature description given in the source link.
Descriprion:
The BGP conditional advertisement feature uses the non-exist-map or exist-map
and the advertise-map keywords of the neighbor advertise-map command in order
to track routes by the route prefix.
non-exist-map :
If a route prefix is not present in output of the non-exist-map command, then
the route specified by the advertise-map command is announced.
exist-map :
If a route prefix is present in output of the exist-map command, then the route
specified by the advertise-map command is announced.
The conditional BGP announcements are sent in addition to the normal
announcements that a BGP router sends to its peers.
The conditional advertisement process is triggered by the BGP scanner process,
which runs every 60 seconds. This means that the maximum time for the conditional
advertisement to take effect is 60 seconds. The conditional advertisement can take
effect sooner, depending on when the tracked route is removed from the BGP table
and when the next instance of the BGP scanner occurs.
Sample Configuration on DUT
---------------------------
Router2# show running-config
Building configuration...
Current configuration:
!
frr version 7.6-dev-MyOwnFRRVersion
frr defaults traditional
hostname router
log file /var/log/frr/bgpd.log
log syslog informational
hostname Router2
service integrated-vtysh-config
!
debug bgp updates in
debug bgp updates out
!
debug route-map
!
ip route 200.200.0.0/16 blackhole
ipv6 route 2001:db8::200/128 blackhole
!
interface enp0s9
ip address 10.10.10.2/24
!
interface enp0s10
ip address 10.10.20.2/24
!
interface lo
ip address 2.2.2.2/24
ipv6 address 2001:db8::2/128
!
router bgp 2
bgp log-neighbor-changes
no bgp ebgp-requires-policy
neighbor 10.10.10.1 remote-as 1
neighbor 10.10.20.3 remote-as 3
!
address-family ipv4 unicast
network 2.2.2.0/24
network 200.200.0.0/16
neighbor 10.10.10.1 soft-reconfiguration inbound
neighbor 10.10.10.1 advertise-map ADVERTISE non-exist-map CONDITION
neighbor 10.10.20.3 soft-reconfiguration inbound
exit-address-family
!
address-family ipv6 unicast
network 2001:db8::2/128
network 2001:db8::200/128
neighbor 10.10.10.1 activate
neighbor 10.10.10.1 soft-reconfiguration inbound
neighbor 10.10.10.1 advertise-map ADVERTISE_6 non-exist-map CONDITION_6
neighbor 10.10.20.3 activate
neighbor 10.10.20.3 soft-reconfiguration inbound
exit-address-family
!
access-list CONDITION seq 5 permit 3.3.3.0/24
access-list ADVERTISE seq 5 permit 2.2.2.0/24
access-list ADVERTISE seq 6 permit 200.200.0.0/16
access-list ADVERTISE seq 7 permit 20.20.0.0/16
!
ipv6 access-list ADVERTISE_6 seq 5 permit 2001:db8::2/128
ipv6 access-list CONDITION_6 seq 5 permit 2001:db8::3/128
!
route-map ADVERTISE permit 10
match ip address ADVERTISE
!
route-map CONDITION permit 10
match ip address CONDITION
!
route-map ADVERTISE_6 permit 10
match ipv6 address ADVERTISE_6
!
route-map CONDITION_6 permit 10
match ipv6 address CONDITION_6
!
line vty
!
end
Router2#
Withdraw when non-exist-map prefixes present in BGP table:
----------------------------------------------------------
Router2# show ip bgp all wide
For address family: IPv4 Unicast
BGP table version is 8, local router ID is 2.2.2.2, vrf id 0
Default local pref 100, local AS 2
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 1.1.1.0/24 10.10.10.1 0 0 1 i
*> 2.2.2.0/24 0.0.0.0 0 32768 i
*> 3.3.3.0/24 10.10.20.3 0 0 3 i
*> 200.200.0.0/16 0.0.0.0 0 32768 i
Displayed 4 routes and 4 total paths
For address family: IPv6 Unicast
BGP table version is 8, local router ID is 2.2.2.2, vrf id 0
Default local pref 100, local AS 2
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 2001:db8::1/128 fe80::a00:27ff:fecb:ad57 0 0 1 i
*> 2001:db8::2/128 :: 0 32768 i
*> 2001:db8::3/128 fe80::a00:27ff:fe76:6738 0 0 3 i
*> 2001:db8::200/128 :: 0 32768 i
Displayed 4 routes and 4 total paths
Router2#
Router2# show ip bgp neighbors 10.10.10.1
BGP neighbor is 10.10.10.1, remote AS 1, local AS 2, external link
!--- Output suppressed.
For address family: IPv4 Unicast
Update group 9, subgroup 5
Packet Queue length 0
Inbound soft reconfiguration allowed
Community attribute sent to this neighbor(all)
Condition NON_EXIST, Condition-map *CONDITION, Advertise-map *ADVERTISE, status: Withdraw
1 accepted prefixes
For address family: IPv6 Unicast
Update group 10, subgroup 6
Packet Queue length 0
Inbound soft reconfiguration allowed
Community attribute sent to this neighbor(all)
Condition NON_EXIST, Condition-map *CONDITION_6, Advertise-map *ADVERTISE_6, status: Withdraw
1 accepted prefixes
!--- Output suppressed.
Router2#
Here 2.2.2.0/24 & 200.200.0.0/16 (prefixes in advertise-map) are withdrawn
by conditional advertisement scanner as the prefix(3.3.3.0/24) specified
by non-exist-map is present in BGP table.
Router2# show ip bgp all neighbors 10.10.10.1 advertised-routes wide
For address family: IPv4 Unicast
BGP table version is 8, local router ID is 2.2.2.2, vrf id 0
Default local pref 100, local AS 2
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 1.1.1.0/24 0.0.0.0 0 1 i
*> 3.3.3.0/24 0.0.0.0 0 3 i
Total number of prefixes 2
For address family: IPv6 Unicast
BGP table version is 8, local router ID is 2.2.2.2, vrf id 0
Default local pref 100, local AS 2
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 2001:db8::1/128 :: 0 1 i
*> 2001:db8::3/128 :: 0 3 i
*> 2001:db8::200/128 :: 0 32768 i
Total number of prefixes 3
Router2#
Advertise when non-exist-map prefixes not present in BGP table:
---------------------------------------------------------------
After Removing 3.3.3.0/24 (prefix present in non-exist-map),
2.2.2.0/24 & 200.200.0.0/16 (prefixes present in advertise-map) are advertised
Router2# show ip bgp all wide
For address family: IPv4 Unicast
BGP table version is 9, local router ID is 2.2.2.2, vrf id 0
Default local pref 100, local AS 2
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 1.1.1.0/24 10.10.10.1 0 0 1 i
*> 2.2.2.0/24 0.0.0.0 0 32768 i
*> 200.200.0.0/16 0.0.0.0 0 32768 i
Displayed 3 routes and 3 total paths
For address family: IPv6 Unicast
BGP table version is 9, local router ID is 2.2.2.2, vrf id 0
Default local pref 100, local AS 2
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 2001:db8::1/128 fe80::a00:27ff:fecb:ad57 0 0 1 i
*> 2001:db8::2/128 :: 0 32768 i
*> 2001:db8::200/128 :: 0 32768 i
Displayed 3 routes and 3 total paths
Router2#
Router2# show ip bgp neighbors 10.10.10.1
!--- Output suppressed.
For address family: IPv4 Unicast
Update group 9, subgroup 5
Packet Queue length 0
Inbound soft reconfiguration allowed
Community attribute sent to this neighbor(all)
Condition NON_EXIST, Condition-map *CONDITION, Advertise-map *ADVERTISE, status: Advertise
1 accepted prefixes
For address family: IPv6 Unicast
Update group 10, subgroup 6
Packet Queue length 0
Inbound soft reconfiguration allowed
Community attribute sent to this neighbor(all)
Condition NON_EXIST, Condition-map *CONDITION_6, Advertise-map *ADVERTISE_6, status: Advertise
1 accepted prefixes
!--- Output suppressed.
Router2#
Router2# show ip bgp all neighbors 10.10.10.1 advertised-routes wide
For address family: IPv4 Unicast
BGP table version is 9, local router ID is 2.2.2.2, vrf id 0
Default local pref 100, local AS 2
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 1.1.1.0/24 0.0.0.0 0 1 i
*> 2.2.2.0/24 0.0.0.0 0 32768 i
*> 200.200.0.0/16 0.0.0.0 0 32768 i
Total number of prefixes 3
For address family: IPv6 Unicast
BGP table version is 9, local router ID is 2.2.2.2, vrf id 0
Default local pref 100, local AS 2
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 2001:db8::1/128 :: 0 1 i
*> 2001:db8::2/128 :: 0 32768 i
*> 2001:db8::200/128 :: 0 32768 i
Total number of prefixes 3
Router2#
Signed-off-by: Madhuri Kuruganti <k.madhuri@samsung.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>
We have this pattern in the code base:
if (thread)
THREAD_OFF(thread);
If we look at THREAD_OFF we check to see if thread
is non-null too. So we have a double check.
This is unnecessary. Convert to just using THREAD_OFF
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
This is needed to avoid mangling update-group which is used for many peers.
Sent prefix count is managed by update-groups.
Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com>
Remove mid-string line breaks, cf. workflow doc:
.. [#tool_style_conflicts] For example, lines over 80 characters are allowed
for text strings to make it possible to search the code for them: please
see `Linux kernel style (breaking long lines and strings)
<https://www.kernel.org/doc/html/v4.10/process/coding-style.html#breaking-long-lines-and-strings>`_
and `Issue #1794 <https://github.com/FRRouting/frr/issues/1794>`_.
Scripted commit, idempotent to running:
```
python3 tools/stringmangle.py --unwrap `git ls-files | egrep '\.[ch]$'`
```
Signed-off-by: David Lamparter <equinox@diac24.net>
This is the bulk part extracted from "bgpd: Convert from `struct
bgp_node` to `struct bgp_dest`". It should not result in any functional
change.
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
Some were converted to bool, where true/false status is needed.
Converted to void only those, where the return status was only false or true.
Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com>
Before the fix:
2019/11/14 19:52:21 BGP: peer 192.168.2.5 deleted from subgroup s4peer
cnt 0 - missing space after s4 before peer
Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com>
Include the coalesce time for the update group `show bgp update-group`
command as well as print out how long the coalesce timer waited
for on the timer pop.
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
The peer's outgoing routemap should not be displaying a 'X'
appended to the front of the name. This will create
confusion.
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
It doesn't make much sense for a hash function to modify its argument,
so const the hash input.
BGP does it in a couple places, those cast away the const. Not great but
not any worse than it was.
Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
The FIFO_* stuff in lib/fifo.h is no different from a simple unsorted
list. Just use DECLARE_LIST here so we can get rid of FIFO_*.
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
The motivation for this patch is to address a concerning behavior of
tx-addpath-bestpath-per-AS. Prior to this patch, all paths' TX ID was
pre-determined as the path was received from a peer. However, this meant
that any time the path selected as best from an AS changed, bgpd had no
choice but to withdraw the previous best path, and advertise the new
best-path under a new TX ID. This could cause significant network
disruption, especially for the subset of prefixes coming from only one
AS that were also communicated over a bestpath-per-AS session.
The patch's general approach is best illustrated by
txaddpath_update_ids. After a bestpath run (required for best-per-AS to
know what will and will not be sent as addpaths) ID numbers will be
stripped from paths that no longer need to be sent, and held in a pool.
Then, paths that will be sent as addpaths and do not already have ID
numbers will allocate new ID numbers, pulling first from that pool.
Finally, anything left in the pool will be returned to the allocator.
In order for this to work, ID numbers had to be split by strategy. The
tx-addpath-All strategy would keep every ID number "in use" constantly,
preventing IDs from being transferred to different paths. Rather than
create two variables for ID, this patch create a more generic array that
will easily enable more addpath strategies to be implemented. The
previously described ID manipulations will happen per addpath strategy,
and will only be run for strategies that are enabled on at least one
peer.
Finally, the ID numbers are allocated from an allocator that tracks per
AFI/SAFI/Addpath Strategy which IDs are in use. Though it would be very
improbable, there was the possibility with the free-running counter
approach for rollover to cause two paths on the same prefix to get
assigned the same TX ID. As remote as the possibility is, we prefer to
not leave it to chance.
This ID re-use method is not perfect. In some cases you could still get
withdraw-then-add behaviors where not strictly necessary. In the case of
bestpath-per-AS this requires one AS to advertise a prefix for the first
time, then a second AS withdraws that prefix, all within the space of an
already pending MRAI timer. In those situations a withdraw-then-add is
more forgivable, and fixing it would probably require a much more
significant effort, as IDs would need to be moved to ADVs instead of
paths.
Signed-off-by Mitchell Skiba <mskiba@amazon.com>
The ->hash_cmp and linked list ->cmp functions were sometimes
being used interchangeably and this really is not a good
thing. So let's modify the hash_cmp function pointer to return
a boolean and convert everything to use the new syntax.
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
When a subgroup splits to form a new subgroup because of policy changes
for a peer, new subgroup copies adj out(state about advertised routes)
from the parent subgroup. At the same time, it should also copy
scount(advertised prefix count) to the new subgroup for the count to be
in sync with the adj_out for the subgroup.
Signed-off-by: Ameya Dharkar <adharkar@vmware.org>
Do a straight conversion of `struct bgp_info` to `struct bgp_path_info`.
This commit will setup the rename of variables as well.
This is being done because `struct bgp_info` is not descriptive
of what this data actually is. It is path information for routes
that we keep to build the actual routes nexthops plus some extra
information.
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
Removed in earlier version where the I/O pthread busy-waited for packets
to be posted to an output queue. Now that it's poll()-based, it's
necessary once again. Although this time we can say what we're actually
doing instead of a side effect of a write job.
Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
This fixes the broken indentation of several foreach loops throughout
the code.
From clang's documentation[1]:
ForEachMacros: A vector of macros that should be interpreted as foreach
loops instead of as function calls.
[1] http://clang.llvm.org/docs/ClangFormatStyleOptions.html
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
This attempt at optimization has cost us more than a week's worth of
time on several people hunting down the subtle bug that it was missing
an increment on attr->lcommunity.
This is absolutely not worth the maintenance cost.
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
1) Add hash names to all hash_create calls
2) Fix community_hash, ecommunity_hash and lcommunity_hash key
creation
3) Fix output of community and lcommunity iterators( why would
we want to see the memory location of the backet? ).
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
This reverts commit c14777c6bf.
clang 5 is not widely available enough for people to indent with. This
is particularly problematic when rebasing/adjusting branches.
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
