BSP Developer's Guide

H
Implementing a MUX-Based Network Interface Driver
H.5.1 Required Structures for a Driver
Within your driver, you must allocate and initialize an END_OBJ. Your driver also
needs to allocate and initialize the structures referenced in END_OBJ structures,
such as DEV_OBJ, NET_FUNCS, and M2_INTERFACETBL. To pass packets up to the
MUX, use an mBlk structure.
Providing Network Device Abstraction: END_OBJ
Your endLoad( ) entry point must allocate, initialize, and return an END_OBJ
structure. The MUX uses this END_OBJ structure as a place to store the tools it
needs to manipulate the stack and the device driver. These tools include data as
well as pointers to functions. The END_OBJ structure is defined in end.h as follows:
typedef struct end_object
{
NODE node; /* root of the device hierarchy */
DEV_OBJ devObject; /* accesses your device’s ctrl struct */
FUNCPTR receiveRtn; /* routine to call on reception */
BOOL attached; /* indicates unit is attached */
SEM_ID txSem; /* transmitter semaphore */
long flags; /* various flags */
struct net_funcs *pFuncTable; /* function table */
M2_INTERFACETBL mib2Tbl; /* MIBII counters */
struct ETHER_MULTI *pAddrList; /* head of the multicast address list */
int nMulti; /* number of elements in the list */
LIST protocols; /* protocol node list */
BOOL snarfProto; /* is someone snarfing us? */
void* pMemPool; /* memory cookie used by MUX bufr mgr. */
M2_ID* pMib2Tbl; /* RFC 2233 MIB objects */
} END_OBJ;
H
Your driver must set and manage some of these members. Other members are
MUX-managed. To know which are which, read the following member
descriptions:
node
The root of the device hierarchy. The MUX sets the value of this member. Your
driver should treat it as opaque.
devObject
The DEV_OBJ structure for this device. Your driver must set this value at load
time. See Tracking Your Device’s Control Structure: DEV_OBJ, p.285.
receiveRtn
A function pointer that references a muxReceive( ) function. The MUX
supplies this pointer by the completion of the muxDevLoad( ) call that loads
283