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tools: fix peer-group deletion in frr-reload

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All of peers and respective configs are wiped out when
pee-group is removed.

In an attempt to remove peer-group and its associated peers
configs via frr-reload fails if the peer-group is removed first.

To pass the peer-group config removal via frr-reload following
steps are taken:
Find the bgp context to which peer-group belongs.
Find the peer-group associated peer(s) and store them in a list.
Remove the peers config lines from the pending list.
Move the peer-group deletion line to end of the pending list so
any remaining peer-group associated config can be removed successfully.

The above steps take 3 iterations over the pending list and scales
linearly.

Ticket:2656351
Reviewed By:CCR-11575
Testing Done:

Broken:

config:
router bgp 5544
 neighbor PG1 peer-group
 neighbor PG1 remote-as external
 neighbor swp10 interface peer-group PG1
 neighbor swp10 timers 3 9

failed frr-reload log:
2021-05-17 22:02:42,608  INFO: Executed "router bgp 5544  no neighbor
PG1 peer-group"
2021-05-17 22:02:42,708  INFO: Failed to execute router bgp 5544  no
neighbor PG1 remote-as external
2021-05-17 22:02:42,808  INFO: Failed to execute router bgp 5544  no
neighbor PG1 remote-as
2021-05-17 22:02:42,906  INFO: Failed to execute router bgp 5544  no
neighbor PG1
2021-05-17 22:02:43,007  INFO: Failed to execute router bgp 5544  no
neighbor
2021-05-17 22:02:43,106  INFO: Failed to execute router bgp 5544  no
2021-05-17 22:02:43,106 ERROR: "router bgp 5544 --  no" we failed to
remove this command
2021-05-17 22:02:43,107 ERROR: % Create the peer-group or interface
first

With fix:
2021-05-17 22:05:27,687  INFO: Executed "router bgp 5544  no neighbor
PG1 remote-as external"
2021-05-17 22:05:27,791  INFO: Executed "router bgp 5544  no neighbor
PG1 peer-group"

Signed-off-by: Chirag Shah <chirag@nvidia.com>
This commit is contained in:
Chirag Shah 2021-05-15 19:41:43 -07:00
parent 978f4b32eb
commit 934c84a02b
1 changed files with 170 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

170
tools/frr-reload.py
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@ -1095,6 +1095,175 @@ def check_for_exit_vrf(lines_to_add, lines_to_del):
return (lines_to_add, lines_to_del)
"""
This method handles deletion of bgp peer group config.
The objective is to delete config lines related to peers
associated with the peer-group and move the peer-group
config line to the end of the lines_to_del list.
"""
def delete_move_lines(lines_to_add, lines_to_del):
del_dict = dict()
# Stores the lines to move to the end of the pending list.
lines_to_del_to_del = []
# Stores the lines to move to end of the pending list.
lines_to_del_to_app = []
found_pg_del_cmd = False
"""
When "neighbor <pg_name> peer-group" under a bgp instance is removed,
it also deletes the associated peer config. Any config line below no form of
peer-group related to a peer are errored out as the peer no longer exists.
To cleanup peer-group and associated peer(s) configs:
- Remove all the peers config lines from the pending list (lines_to_del list).
- Move peer-group deletion line to the end of the pending list, to allow
removal of any of the peer-group specific configs.
Create a dictionary of config context (i.e. router bgp vrf x).
Under each context node, create a dictionary of a peer-group name.
Append a peer associated to the peer-group into a list under a peer-group node.
Remove all of the peer associated config lines from the pending list.
Append peer-group deletion line to end of the pending list.
Example:
neighbor underlay peer-group
neighbor underlay remote-as external
neighbor underlay advertisement-interval 0
neighbor underlay timers 3 9
neighbor underlay timers connect 10
neighbor swp1 interface peer-group underlay
neighbor swp1 advertisement-interval 0
neighbor swp1 timers 3 9
neighbor swp1 timers connect 10
neighbor swp2 interface peer-group underlay
neighbor swp2 advertisement-interval 0
neighbor swp2 timers 3 9
neighbor swp2 timers connect 10
neighbor swp3 interface peer-group underlay
neighbor uplink1 interface remote-as internal
neighbor uplink1 advertisement-interval 0
neighbor uplink1 timers 3 9
neighbor uplink1 timers connect 10
New order:
"router bgp 200 no bgp bestpath as-path multipath-relax"
"router bgp 200 no neighbor underlay advertisement-interval 0"
"router bgp 200 no neighbor underlay timers 3 9"
"router bgp 200 no neighbor underlay timers connect 10"
"router bgp 200 no neighbor uplink1 advertisement-interval 0"
"router bgp 200 no neighbor uplink1 timers 3 9"
"router bgp 200 no neighbor uplink1 timers connect 10"
"router bgp 200 no neighbor underlay remote-as external"
"router bgp 200 no neighbor uplink1 interface remote-as internal"
"router bgp 200 no neighbor underlay peer-group"
"""
for (ctx_keys, line) in lines_to_del:
if (
ctx_keys[0].startswith("router bgp")
and line
and line.startswith("neighbor ")
):
"""
When 'neighbor <peer> remote-as <>' is removed it deletes the peer,
there might be a peer associated config which also needs to be removed
prior to peer.
Append the 'neighbor <peer> remote-as <>' to the lines_to_del.
Example:
neighbor uplink1 interface remote-as internal
neighbor uplink1 advertisement-interval 0
neighbor uplink1 timers 3 9
neighbor uplink1 timers connect 10
Move to end:
neighbor uplink1 advertisement-interval 0
neighbor uplink1 timers 3 9
neighbor uplink1 timers connect 10
...
neighbor uplink1 interface remote-as internal
"""
# 'no neighbor peer [interface] remote-as <>'
nb_remoteas = "neighbor (\S+) .*remote-as (\S+)"
re_nb_remoteas = re.search(nb_remoteas, line)
if re_nb_remoteas:
lines_to_del_to_app.append((ctx_keys, line))
"""
{'router bgp 65001': {'PG': [], 'PG1': []},
'router bgp 65001 vrf vrf1': {'PG': [], 'PG1': []}}
"""
if ctx_keys[0] not in del_dict:
del_dict[ctx_keys[0]] = dict()
# find 'no neighbor <pg_name> peer-group'
re_pg = re.match("neighbor (\S+) peer-group$", line)
if re_pg and re_pg.group(1) not in del_dict[ctx_keys[0]]:
del_dict[ctx_keys[0]][re_pg.group(1)] = list()
for (ctx_keys, line) in lines_to_del_to_app:
lines_to_del.remove((ctx_keys, line))
lines_to_del.append((ctx_keys, line))
if found_pg_del_cmd == False:
return (lines_to_add, lines_to_del)
"""
{'router bgp 65001': {'PG': ['10.1.1.2'], 'PG1': ['10.1.1.21']},
'router bgp 65001 vrf vrf1': {'PG': ['10.1.1.2'], 'PG1': ['10.1.1.21']}}
"""
for (ctx_keys, line) in lines_to_del:
if (
ctx_keys[0].startswith("router bgp")
and line
and line.startswith("neighbor ")
):
if ctx_keys[0] in del_dict:
for pg_key in del_dict[ctx_keys[0]]:
# 'neighbor <peer> [interface] peer-group <pg_name>'
nb_pg = "neighbor (\S+) .*peer-group %s$" % pg_key
re_nbr_pg = re.search(nb_pg, line)
if (
re_nbr_pg
and re_nbr_pg.group(1) not in del_dict[ctx_keys[0]][pg_key]
):
del_dict[ctx_keys[0]][pg_key].append(re_nbr_pg.group(1))
lines_to_del_to_app = []
for (ctx_keys, line) in lines_to_del:
if (
ctx_keys[0].startswith("router bgp")
and line
and line.startswith("neighbor ")
):
if ctx_keys[0] in del_dict:
for pg in del_dict[ctx_keys[0]]:
for nbr in del_dict[ctx_keys[0]][pg]:
nb_exp = "neighbor %s .*" % nbr
re_nb = re.search(nb_exp, line)
# add peer configs to delete list.
if re_nb and line not in lines_to_del_to_del:
lines_to_del_to_del.append((ctx_keys, line))
pg_exp = "neighbor %s peer-group$" % pg
re_pg = re.match(pg_exp, line)
if re_pg:
lines_to_del_to_app.append((ctx_keys, line))
for (ctx_keys, line) in lines_to_del_to_del:
lines_to_del.remove((ctx_keys, line))
for (ctx_keys, line) in lines_to_del_to_app:
lines_to_del.remove((ctx_keys, line))
lines_to_del.append((ctx_keys, line))
return (lines_to_add, lines_to_del)
def ignore_delete_re_add_lines(lines_to_add, lines_to_del):
# Quite possibly the most confusing (while accurate) variable names in history
@ -1724,6 +1893,7 @@ def compare_context_objects(newconf, running):
(lines_to_add, lines_to_del) = ignore_delete_re_add_lines(
lines_to_add, lines_to_del
)
(lines_to_add, lines_to_del) = delete_move_lines(lines_to_add, lines_to_del)
(lines_to_add, lines_to_del) = ignore_unconfigurable_lines(
lines_to_add, lines_to_del
)