value returned from a successful call to net_protocol_register().
hook
pointer to a hook_t structure.
DESCRIPTION
The net_hook_register() function uses hooks that allow callbacks to be registered with events that belong to a network protocol. A successful call to net_hook_register() requires that a valid handle for a network protocol be provided (the net parameter),
along with a hook description that includes a reference to an available event.
While it is possible to use the same hook_t structure with multiple calls to net_hook_register(), it is not encouraged.
The hook_t structure passed in with this function is described by hook_t(9S). The following describes how this structure is used.
h_func
Must be non-NULL and represent a function that fits the specified interface.
h_name
Gives the hook a name that represents its owner. No duplication of h_name among the hooks present for an event is allowed.
h_flags
Currently unused and must be set to 0.
h_hint, h_hintvalue
Specify a hint to net_hook_register() on how to insert this hook. If the hint cannot be specified, then an error is returned.
h_arg;
May take any value that the consumer wishes to have passed back when the hook is activated.
RETURN VALUES
If the net_hook_register() function succeeds, 0 is returned. Otherwise, one of the following errors is returned:
ENOMEM
The system cannot allocate any more memory to support registering this hook.
ENXIO
A hook cannot be found among the given family of events.
EEXIST
A hook with the given h_name already exists on that event.
ESRCH
A before or after dependency cannot be satisfied due to the hook with
EBUSY
The h_hint field specifies a hint that cannot currently be satisfied because it conflicts with another hook. An example of this might be specifying HH_FIRST or HH_LAST when another hook has already been registered with this
value.
CONTEXT
The net_hook_register() function may be called from user or kernel context.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
