The maximum allowed value of the sysfs device index entry was limited to
16383 (2^14-1) to avoid the generation of unreasonable onboard interface
names.
For s390 the index can assume a value of up to 65535 (2^16-1) which is
now allowed depending on the new naming flag NAMING_16BIT_INDEX.
Larger index values are considered unreasonable and remain to be
ignored.
Some interfaces require that the DHCPOFFER message is sent via broadcast
if they can't receive unicast messages before they've been configured
with an IP address.
E.g., s390 ccwgroup network interfaces operating in layer3 mode face
this limitation. This can prevent the interfaces from receiving an
IP address via DHCP, if the have been configured for layer3.
To allow DHCP over such interfaces, we're introducing a new device
property ID_NET_DHCP_BROADCAST which can be set for those.
The networkd DHCP client will check whether this property is set
for an interface, and if so will set the broadcast flag, unless
the network configuration for the interface has an explicit
RequestBroadcast setting.
Besides that, we're adding a udev rule to set this device property
for ccwgroup devices operating in layer3 mode, which is the case
if the ID_NET_DRIVER property is qeth_l3.
Supercedes #18829
The s390 PCI driver assigns the hotplug slot name from the
function_id attribute of the PCI device using a 8 char hexadecimal
format to match the underlying firmware/hypervisor notation.
Further, there's always a one-to-one mapping between a PCI
function and a hotplug slot, as individual functions can
hot plugged even for multi-function devices.
As the generic matching code will always try to parse the slot
name in /sys/bus/pci/slots as a positive decimal number, either
a wrong value might be produced for ID_NET_NAME_SLOT if
the slot name consists of decimal numbers only, or none at all
if a character in the range from 'a' to 'f' is encountered.
Additionally, the generic code assumes that two interfaces
share a hotplug slot, if they differ only in the function part
of the PCI address. E.g., for an interface with the PCI address
dddd:bb:aa.f, it will match the device to the first slot with
an address dddd:bb:aa. As more than one slot may have this address
for the s390 PCI driver, the wrong slot may be selected.
To resolve this we're adding a new naming schema version with the
flag NAMING_SLOT_FUNCTION_ID, which enables the correct matching
of hotplug slots if the device has an attribute named function_id.
The ID_NET_NAME_SLOT property will only be produced if there's
a file /sys/bus/pci/slots/<slotname> where <slotname> matches
the value of /sys/bus/pci/devices/.../function_id in 8 char
hex notation.
Fixes#19016
See also #19078
Viktor Mihajlovski