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
(cherry picked from commit 905adabdba)
(cherry picked from commit 5a49a2f6b2)
This commit is contained in:
Beniamino Galvani 2022-08-24 16:52:52 +02:00
parent 8011d0b32b
commit d0fb3fbf8e

View file

@ -6426,6 +6426,7 @@ 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;
nm_auto_nmpobj const NMPObject *pllink_keep_alive = NULL;
const NMPlatformLink *pllink;
const char *str;
@ -6472,9 +6473,9 @@ device_link_changed(gpointer user_data)
if (ifindex == nm_device_get_ip_ifindex(self))
_stats_update_counters_from_pllink(self, pllink);
had_hw_addr = (priv->hw_addr != NULL);
nm_device_update_hw_address(self);
got_hw_addr = (!had_hw_addr && priv->hw_addr);
had_hw_addr = (priv->hw_addr != NULL);
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);
if (pllink->name[0] && !nm_streq(priv->iface, pllink->name)) {
@ -6525,6 +6526,8 @@ 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);