Default Operations

Since many protocols' UPI operations look very similar, the x-kernel provides some library operations which do much of the standard work of some of the operations. Many protocols can call these default operations and greatly simplify their own implementations of these routines.

defaultOpenEnable

Binds key to an enable object with hlpRcv and hlpType. If a previous binding exists for the given key and hlps, the reference count of that enable object will be increased. defaultOpenEnable will fail if a previous binding exists for this key that does not match the hlps.

xkern_return_t defaultOpenEnable ( Map m, XObj hlpRcv, XObj hlpType, void * key )

defaultOpenDisable

Undoes the effect of a previous defaultOpenEnable. Returns failure if no appropriate enable object exists (e.g., if nothing exists for the given key or if the hlps don't match the saved values in the enable object.)

xkern_return_t defaultOpenDisable ( Map m, XObj hlpRcv, XObj hlpType, void * key )

defaultOpenDisableAll

Removes all enable objects bound in map with hlpRcv. If f is non-zero, it is called with the (key, Enable *) pair for each Enable object in the map before it is removed.

xkern_return_t defaultOpenDisableAll ( Map m, XObj hlpRcv, DisableAllFunc f )

typedef void (*DisableAllFunc ) ( void * key, Enable * e )

defaultVirtualOpenEnable

Designed to be used by virtual protocols. In addition to the binding performed by defaultOpenEnable, an xOpenEnable is performed on each lower protocol in the null-terminated array llp (using participants p, causing the lower protocols to deliver packets for hlpType to the virtual protocol self. If any of these xOpenEnables fail, defaultVirtualOpenEnable backs out of the entire operation.

Assumes that the passive map is keyed on hlpType.

defaultVirtualOpenDisable

Undoes the effect of a previous defaultVirtualOpenEnable.

Usage

Here is an example of how a protocol might simplify its enable/disable routines using these operations:

static xkern_return_t
yapOpenEnable( XObj self, XObj hlpRcv, XObj hlpType, Part *p )
{
    long    key;
    PState  *ps = self->state;
    
    key = getRelProtNum(hlpType, self));
    return defaultOpenEnable(ps->passive_map, hlpRcv, hlpType, &key);
}

static xkern_return_t
yapOpenDisable( XObj self, XObj hlpRcv, XObj hlpType, Part *p )
{
    long    key;
    PState  *ps = self->state;
    
    key = getRelProtNum(hlpType, self));
    return defaultOpenDisable(ps->passive_map, hlpRcv, hlpType, &key);
}

static xkern_return_t
yapOpenDisableAll( XObj self, XObj hlpRcv )
{
    PState  *ps = self->state;

    return defaultOpenDisableAll(ps->passive_map, hlpRcv, 0);
}