NM not listing all configured connections

[Dariusz Gadomski]

If a large number of networks is configured it may be impossible to connect to some of them as a regular user, because they are not listed.

It affects all the versions I tested: trusty, utopic, vivid and wily.

Steps to reproduce:
1. Configure a large number of networks (in my case it was 250).
2. Run nmcli c.

Expected result:
nmcli should list all available networks.

Actual result:
Only a random (yes, it changes a bit with every call) subset of all connection is displayed - about 130 connections.

If there are e.g. VPN connections among all connections you may end up with being not able to connect to them until you get lucky and the connection you need will be "drawn" to the available pool.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: network-manager 0.9.10.0-4ubuntu16
ProcVersionSignature: Ubuntu 4.0.0-4.6-generic 4.0.7
Uname: Linux 4.0.0-4-generic x86_64
ApportVersion: 2.17.3-0ubuntu4
Architecture: amd64
CurrentDesktop: Unity
Date: Fri Jul 10 15:36:35 2015
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
IpRoute:
 default via 192.168.0.1 dev wlan0 proto static metric 400
 169.254.0.0/16 dev wlan0 scope link metric 1000
 192.168.0.0/24 dev wlan0 proto kernel scope link src 192.168.0.14
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
 WimaxEnabled=true
SourcePackage: network-manager
UpgradeStatus: Upgraded to wily on 2015-06-30 (10 days ago)
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH
 wlan0 wifi connected /org/freedesktop/NetworkManager/Devices/1 UPC0052966 0049ac7c-275c-47a5-beb8-aac3311a371c /org/freedesktop/NetworkManager/ActiveConnection/0
 lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/0 -- -- --
nmcli-nm: Error: command ['nmcli', '-f', 'all', 'nm'] failed with exit code 2: Error: Object 'nm' is unknown, try 'nmcli help'.

[Dariusz Gadomski (dgadomski)]

I have debugged the network-manager daemon (src/settings/nm-settings.c:234 impl_settings_list_connections) and nmcli (cli/src/connections.c:8633 get_connections_cb).

It looks that a correct number of connections is sent from the daemon and a limited number is received in the nmcli. Maybe it's due to some DBus quota on message size?

[Dariusz Gadomski (dgadomski)]

I have been playing with copying some limit values from /etc/dbus-1/session.conf to system.conf and by bisection I found out that adding the following settings:
<limit name="max_replies_per_connection">50000</limit>
makes the problem disappear.