device: restart DHCP when the MAC changes

If the MAC changes there is the possibility that the DHCP client will
not be able to renew the address because it uses the old MAC as
CHADDR. Depending on the implementation, the DHCP server might use
CHADDR (so, the old address) as the destination MAC for DHCP replies,
and those packets will be lost.

To avoid this problem, restart the DHCP client when the MAC changes.

https://bugzilla.redhat.com/show_bug.cgi?id=2110000
This commit is contained in:
Beniamino Galvani 2022-08-24 16:52:52 +02:00
parent 4f552f53bb
commit 34714ff8ff

View file

@ -6637,6 +6637,7 @@ device_link_changed(gpointer user_data)
NMDeviceClass *klass = NM_DEVICE_GET_CLASS(self);
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE(self);
gboolean ip_ifname_changed = FALSE;
gboolean hw_addr_changed = FALSE;
nm_auto_nmpobj const NMPObject *pllink_keep_alive = NULL;
const NMPlatformLink *pllink;
const char *str;
@ -6684,7 +6685,7 @@ device_link_changed(gpointer user_data)
_stats_update_counters_from_pllink(self, pllink);
had_hw_addr = (priv->hw_addr != NULL);
nm_device_update_hw_address(self);
hw_addr_changed = nm_device_update_hw_address(self);
got_hw_addr = (!had_hw_addr && priv->hw_addr);
nm_device_update_permanent_hw_address(self, FALSE);
@ -6736,6 +6737,8 @@ device_link_changed(gpointer user_data)
/* Update DHCP, etc, if needed */
if (ip_ifname_changed)
nm_device_update_dynamic_ip_setup(self, "IP interface changed");
else if (hw_addr_changed)
nm_device_update_dynamic_ip_setup(self, "hw-address changed");
was_up = priv->up;
priv->up = NM_FLAGS_HAS(pllink->n_ifi_flags, IFF_UP);