NM sometimes brings an interface temporarily down (for example to
change a VLAN MAC to align it to the parent interface's one). When
this happens, any recv() or send() in n-acd fails, the n-acd instance
is reset to the initial state and a DOWN event is reported to the
manager, which currently does not handle it. The result is an
inconsistent state.
There is no simple way of dealing with the DOWN event in the
manager. What we can do instead is to:
- ignore errors during recv() because there is really nothing we can
do, except for waiting timeouts to expire;
- during probe, ignore errors during send() so that we don't exceed
the probe timeout;
- during announcement, retry after a send() error to ensure we send
all 3 announcements.
https://bugzilla.redhat.com/show_bug.cgi?id=1578675
When doing announcements, use the the timeout specified by RFC
5227. Note that timeout_multiplier might be 0.
This aligns behavior to upstream version of n-acd.
...so that its prototype is compatible with GDestroyNotify:
src/devices/nm-acd-manager.c: In function ‘destroy_address_info’:
/usr/include/glib-2.0/glib/gmem.h:120:31: error: cast between incompatible function types from ‘NAcd * (*)(NAcd *)’ {aka ‘struct NAcd * (*)(struct NAcd *)’} to ‘void (*)(void *)’ [-Werror=cast-function-type]
GDestroyNotify _destroy = (GDestroyNotify) (destroy); \
^
src/devices/nm-acd-manager.c:430:2: note: in expansion of macro ‘g_clear_pointer’
g_clear_pointer (&info->acd, n_acd_free);
^~~~~~~~~~~~~~~
The same change was done upstream, so the subsequent subtree pull of n-acd
won't mess this up.
The README states that a kernel >= 3.0 is enough, however
CLOCK_BOOTTIME is only available since kernel 3.15.
Fall back to CLOCK_MONOTONIC when CLOCK_BOOTTIME is not available.
See: https://github.com/nettools/n-acd/pull/3
Signed-off-by: Beniamino Galvani <bgalvani@redhat.com>
