pppd restores the previous settings for the serial port it uses right
before exiting. It is especially important to do so because otherwise
ModemManager is not able to recover the port as it can receive a hangup
event from the port due to CLOCAL not being restored. However, there is
currently a race condition that produces this issue. This is because
when PHASE_DEAD is notified, pppd still has not restored the port
settings - it does that a bit later, in the die() function.
This patch delays notifying PHASE_DEAD until when the exitnotify() hook
is called by pppd: when this happens the port settings have already been
restored.
There were previously efforts to fix this in commit fe090c34b7, so
PHASE_DEAD was used instead of PHASE_DISCONNECT to notify MM that the
port was disconnected, but that still early to ensure that the port
settings are restored.
The MM traces seen when the bug is triggered are:
ModemManager[2158]: <warn> (ttyACM1): could not re-acquire serial port lock: (5) Input/output error
ModemManager[2158]: <warn> Couldn't load Operator Code: 'Cannot run sequence: 'Could not open serial device ttyACM1: it has been forced close'
https://mail.gnome.org/archives/networkmanager-list/2019-June/msg00014.html
(cherry picked from commit a251712a72)
When NM knows of the ifindex/name of the new PPP interface (through
the SetIfindex() call), it renames it. This can race with the pppd
daemon, which issues ioctl() using the interface name cached in the
global 'ifname' variable:
...
NetworkManager[27213]: <debug> [1515427406.0036] ppp-manager: set-ifindex 71
pppd[27801]: sent [CCP ConfRej id=0x1 <deflate 15> <deflate(old#) 15> <bsd v1 15>]
NetworkManager[27213]: <debug> [1515427406.0036] platform: link: setting 'ppp5' (71) name dsl-ppp
pppd[27801]: sent [IPCP ConfAck id=0x2 <addr 3.1.1.1>]
pppd[27801]: ioctl(SIOCSIFADDR): No such device (line 2473)
pppd[27801]: Interface configuration failed
pppd[27801]: Couldn't get PPP statistics: No such device
...
Fortunately the variable is exposed to plugins and so we can turn the
SetIfindex() D-Bus call into a synchronous one and then update the
value of the 'ifname' global variable with the new interface name
assigned by NM.
If IPV6CP terminates before IPCP, pppd enters the RUNNING phase and we
start IP configuration without having an IP interface set, which
triggers assertions.
Instead, add a SetIfindex() D-Bus method that gets called by the
plugin when pppd becomes RUNNING. The method sets the IP ifindex of
the device and starts IP configuration.
https://bugzilla.redhat.com/show_bug.cgi?id=1515829
Note that:
- we compile some source files multiple times. Most notably those
under "shared/".
- we include a default header "shared/nm-default.h" in every source
file. This header is supposed to setup a common environment by defining
and including parts that are commonly used. As we always include the
same header, the header must behave differently depending
one whether the compilation is for libnm-core, NetworkManager or
libnm-glib. E.g. it must include <glib/gi18n.h> or <glib/gi18n-lib.h>
depending on whether we compile a library or an application.
For that, the source files need the NETWORKMANAGER_COMPILATION #define
to behave accordingly.
Extend the define to be composed of flags. These flags are all named
NM_NETWORKMANAGER_COMPILATION_WITH_*, they indicate which part of the
build are available. E.g. when building libnm-core.la itself, then
WITH_LIBNM_CORE, WITH_LIBNM_CORE_INTERNAL, and WITH_LIBNM_CORE_PRIVATE
are available. When building NetworkManager, WITH_LIBNM_CORE_PRIVATE
is not available but the internal parts are still accessible. When
building nmcli, only WITH_LIBNM_CORE (the public part) is available.
This granularily controls the build.
