HP-UX IPQoS A.01.00 Programmer's Guide (October 2005)

Using the HP-UX IPQoS API
Using Lists
Chapter 2 27
Attaching Objects to Lists
When an object exists in a list it is said to be attached. When an object is created or copied it is
(initially) considered unattached, until it is explicitly attached. To attach a policy or filter to a
list, use the following functions: IpqosAttachPolicy(), IpqosAttachFilter().
Restrictions
There are two restrictions for attaching a filter object to a list:
• The filter must have its name attribute set. The name must be unique.
• If the filter’s destination physical address attribute is set, the length of the address must
be compatible with the adapter object to which the associated policy object is attached.
There are two restrictions for attaching a policy object to a list:
• The policy must have its name attribute set. The name must be unique.
• If the policy’s reservation bandwidth attribute is set, it must be a value such that the
aggregate reservation of all policy objects attached to an adapter object does not exceed
the line speed of the adapter, less 80 Kbps. The 80 Kbps is set aside for classes of traffic
that do not match any specified filters.
In the case of VLANs, the aggregate of the reservations of policies of VLANs that are
based on the same physical adapter, and the policies of the base adapter itself, cannot
exceed the speed of the physical adapter minus the 80Kbps reserved by the implicit
default flow.
There are two functions that remove objects from lists. An object can be detached from the list
by calling one of the delete functions. The object becomes detached when the session is
committed. The object’s memory and resources can be freed by calling one of the destroy
functions.
To delete an object its status must not be IPQOS_STATUS_INACTIVE, otherwise the function
will return IPQOS_E_NOT_ATTACHED.
To destroy an object its status must be IPQOS_STATUS_INACTIVE, otherwise the function will
return the error code IPQOS_E_ALREADY_ATTACHED.
Traversing Lists
As shown in Figure 2-1, the lists are singly-linked and can only be traversed one way.
To obtain the object at the head of an object list, use the following functions:
IpqosGetAdapterListHead(), IpqosGetPolicyListHead(), IpqosGetFilterListHead().