udev: introduce NAMING_STABLE_VIRTUAL_MACS (retroactively)

This is for 6d36464065. It turns out that this is causing more problems than
expected. Let's retroactively introduce naming scheme v241 to conditionalize
this change.

Follow-up for #12792 and 6d36464065. See also
https://bugzilla.suse.com/show_bug.cgi?id=1136600.

$ SYSTEMD_LOG_LEVEL=debug NET_NAMING_SCHEME=v240 build/udevadm test-builtin net_setup_link /sys/class/net/br11
$ SYSTEMD_LOG_LEVEL=debug NET_NAMING_SCHEME=v241 build/udevadm test-builtin net_setup_link /sys/class/net/br11
...
@@ -20,11 +20,13 @@
 link_config: could not set ethtool features for br11
 Could not set offload features of br11: Operation not permitted
 br11: Device has name_assign_type=3
-Using interface naming scheme 'v240'.
+Using interface naming scheme 'v241'.
 br11: Policy *keep*: keeping existing userspace name
 br11: Device has addr_assign_type=1
-br11: No stable identifying information found
-br11: Could not generate persistent MAC: No data available
+br11: Using "br11" as stable identifying information
+br11: Using generated persistent MAC address
+Could not set Alias=, MACAddress= or MTU= on br11: Operation not permitted
+br11: Could not apply link config, ignoring: Operation not permitted
 Unload module index
 Unloaded link configuration context.
 ID_NET_DRIVER=bridge

src/udev/net/link-config.c

@@ -318,10 +318,13 @@ static int get_mac(sd_device *device, MACAddressPolicy policy, struct ether_addr
         } else {
                 uint64_t result;
 
-                r = net_get_unique_predictable_data(device, &result);
+                r = net_get_unique_predictable_data(device,
+                                                    naming_scheme_has(NAMING_STABLE_VIRTUAL_MACS),
+                                                    &result);
                 if (r < 0)
                         return log_device_warning_errno(device, r, "Could not generate persistent MAC: %m");
 
+                log_device_debug(device, "Using generated persistent MAC address");
                 assert_cc(ETH_ALEN <= sizeof(result));
                 memcpy(mac->ether_addr_octet, &result, ETH_ALEN);
         }

src/udev/net/naming-scheme.c

@@ -8,6 +8,7 @@ static const NamingScheme naming_schemes[] = {
         { "v238", NAMING_V238 },
         { "v239", NAMING_V239 },
         { "v240", NAMING_V240 },
+        { "v241", NAMING_V241 },
         { "v243", NAMING_V243 },
         /* … add more schemes here, as the logic to name devices is updated … */
 };

src/udev/net/naming-scheme.h

@@ -27,14 +27,16 @@ typedef enum NamingSchemeFlags {
         NAMING_INFINIBAND          = 1 << 2, /* Use "ib" prefix for infiniband, see 938d30aa98df */
         NAMING_ZERO_ACPI_INDEX     = 1 << 3, /* Use zero acpi_index field, see d81186ef4f6a */
         NAMING_ALLOW_RERENAMES     = 1 << 4, /* Allow re-renaming of devices, see #9006 */
-        NAMING_NETDEVSIM           = 1 << 5, /* Generate names for netdevsim devices, see eaa9d507d855 */
-        NAMING_LABEL_NOPREFIX      = 1 << 6, /* Don't prepend ID_NET_LABEL_ONBOARD with interface type prefix */
+        NAMING_STABLE_VIRTUAL_MACS = 1 << 5, /* Use device name to generate MAC, see 6d3646406560 */
+        NAMING_NETDEVSIM           = 1 << 6, /* Generate names for netdevsim devices, see eaa9d507d855 */
+        NAMING_LABEL_NOPREFIX      = 1 << 7, /* Don't prepend ID_NET_LABEL_ONBOARD with interface type prefix */
 
         /* And now the masks that combine the features above */
         NAMING_V238 = 0,
         NAMING_V239 = NAMING_V238 | NAMING_SR_IOV_V | NAMING_NPAR_ARI,
         NAMING_V240 = NAMING_V239 | NAMING_INFINIBAND | NAMING_ZERO_ACPI_INDEX | NAMING_ALLOW_RERENAMES,
-        NAMING_V243 = NAMING_V240 | NAMING_NETDEVSIM | NAMING_LABEL_NOPREFIX,
+        NAMING_V241 = NAMING_V240 | NAMING_STABLE_VIRTUAL_MACS,
+        NAMING_V243 = NAMING_V241 | NAMING_NETDEVSIM | NAMING_LABEL_NOPREFIX,
 
         _NAMING_SCHEME_FLAGS_INVALID = -1,
 } NamingSchemeFlags;