Bug 1734470 - Reapply DHCPv6 only mode will still get autoconf.
Summary: Reapply DHCPv6 only mode will still get autoconf.
Keywords:
Status: MODIFIED
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: NetworkManager
Version: 8.1
Hardware: x86_64
OS: Linux
high
high
Target Milestone: rc
: 8.2
Assignee: Beniamino Galvani
QA Contact: Desktop QE
URL:
Whiteboard:
Depends On:
Blocks: nmstate-nm-prio 1738635 1772820 1738101
TreeView+ depends on / blocked
 
Reported: 2019-07-30 15:57 UTC by Gris Ge
Modified: 2019-11-15 09:24 UTC (History)
12 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
: 1772820 (view as bug list)
Environment:
Last Closed:
Type: Bug
Target Upstream Version:


Attachments (Terms of Use)
Reproduce script. (1.20 KB, application/x-shellscript)
2019-07-30 15:57 UTC, Gris Ge
no flags Details
System logs with NM trace enabled (200.36 KB, text/plain)
2019-07-30 16:15 UTC, Gris Ge
no flags Details
Script to check RA neigh parameters (1.75 KB, application/x-shellscript)
2019-08-25 08:04 UTC, Beniamino Galvani
no flags Details

Description Gris Ge 2019-07-30 15:57:36 UTC
Created attachment 1594673 [details]
Reproduce script.

Description of problem:

When reapply the change of ipv6.method ignore -> dhcp, the autoconf
will got enabled after some seconds.

nmcli c add  type ethernet ifname dhcpcli \
    connection.id dhcpcli \
    ipv4.method disabled \
    ipv6.method ignore
nmcli c up dhcpcli

nmcli c modify dhcpcli ipv6.method dhcp
nmcli d reapply dhcpcli



Version-Release number of selected component (if applicable):
NetworkManager-1.20.0-0.3.el8.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Download the attached script.
2. sudo bash ./nm_reapply_ipv6.sh
3.

Actual results:
autoconf routes show up at second 7, and disappear second 12, then show up again
at second 17:

Expected results:
No autoconf routes.

Additional info:

Comment 1 Gris Ge 2019-07-30 16:15:11 UTC
The output of reproduce scripts:

====
[fge@el8 ~]$ sudo ./nm_reapply_ipv6.sh
Error: unknown connection 'dhcpcli'.
Error: cannot delete unknown connection(s): 'dhcpcli'.
Cannot find device "dhcpcli"
radvd-2.17-12.el8.x86_64
0
0
Connection 'dhcpcli' (0816d2d0-b070-4d9b-b630-5e4cc806ec48) successfully added.
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/3)
::1 dev lo proto kernel metric 256 pref medium
2001:db8:1::/64 dev dhcpsrv proto kernel metric 256 pref medium
fe80::/64 dev enp1s0 proto kernel metric 100 pref medium
fe80::/64 dev dhcpsrv proto kernel metric 256 pref medium
fe80::/64 dev dhcpcli proto kernel metric 256 pref medium
Connection successfully reapplied to device 'dhcpcli'.
1
2
3
default via fe80::b0ec:c5ff:fedd:b7b2 dev dhcpcli proto ra metric 1024 expires 299sec hoplimit 64 pref medium
4
default via fe80::b0ec:c5ff:fedd:b7b2 dev dhcpcli proto ra metric 1024 expires 298sec hoplimit 64 pref medium
5
default via fe80::b0ec:c5ff:fedd:b7b2 dev dhcpcli proto ra metric 1024 expires 297sec hoplimit 64 pref medium
6
default via fe80::b0ec:c5ff:fedd:b7b2 dev dhcpcli proto ra metric 1024 expires 296sec hoplimit 64 pref medium
7
default via fe80::b0ec:c5ff:fedd:b7b2 dev dhcpcli proto ra metric 1024 expires 295sec hoplimit 64 pref medium
8
9
10
11
12
13
14
15
16
17
default via fe80::b0ec:c5ff:fedd:b7b2 dev dhcpcli proto ra metric 1024 expires 299sec hoplimit 64 pref medium
18
default via fe80::b0ec:c5ff:fedd:b7b2 dev dhcpcli proto ra metric 1024 expires 298sec hoplimit 64 pref medium
19
default via fe80::b0ec:c5ff:fedd:b7b2 dev dhcpcli proto ra metric 1024 expires 297sec hoplimit 64 pref medium
20
default via fe80::b0ec:c5ff:fedd:b7b2 dev dhcpcli proto ra metric 1024 expires 296sec hoplimit 64 pref medium
rm: cannot remove '/etc/dnsmasq.d/test.conf': No such file or directory
Connection 'dhcpcli' (0816d2d0-b070-4d9b-b630-5e4cc806ec48) successfully deleted.
=====

autoconf routes show up at second 3, and disappear second 8, then show up again
at second 17

Comment 2 Gris Ge 2019-07-30 16:15:47 UTC
Created attachment 1594701 [details]
System logs with NM trace enabled

Comment 3 Beniamino Galvani 2019-08-13 12:59:31 UTC
Probably those addresses are added by kernel because we leave 'accept_ra' set to 1, and so kernel does autoconfiguration even when it's disabled in NM.

Comment 6 Beniamino Galvani 2019-08-25 08:04:39 UTC
Created attachment 1607778 [details]
Script to check RA neigh parameters

The branch above disables kernel handling of RAs (accept_ra), that was introduced to fix bug 1068673. The parameters mentioned in the bug (retrans_time, reachable_time) are now handled by NM. This scripts can be used to verify that we still set the parameters correctly.

Comment 8 Edward Haas 2019-11-12 15:46:15 UTC
Requesting a backport to z-stream:

RHV is not expecting traffic disruption while updating a bridge interface.
The issue discussed in this BZ disrupts traffic and connectivity as it requires the usage if "activation" instead of "reapply".

It will be very helpful to have this issue fixed in 8.1.z so RHV can consume it from day 1.


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