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1.1 root 1: /*++
2:
3: Copyright (c) 1989-1993 Microsoft Corporation
4:
5: Module Name:
6:
7: devctx.c
8:
9: Abstract:
10:
11: This module contains code which implements the DEVICE_CONTEXT object.
12: Routines are provided to reference, and dereference transport device
13: context objects.
14:
15: The transport device context object is a structure which contains a
16: system-defined DEVICE_OBJECT followed by information which is maintained
17: by the transport provider, called the context.
18:
19: Environment:
20:
21: Kernel mode
22:
23: Revision History:
24:
25: --*/
26:
27: #include "st.h"
28:
29:
30: VOID
31: StRefDeviceContext(
32: IN PDEVICE_CONTEXT DeviceContext
33: )
34:
35: /*++
36:
37: Routine Description:
38:
39: This routine increments the reference count on a device context.
40:
41: Arguments:
42:
43: DeviceContext - Pointer to a transport device context object.
44:
45: Return Value:
46:
47: none.
48:
49: --*/
50:
51: {
52: ASSERT (DeviceContext->ReferenceCount > 0); // not perfect, but...
53:
54: (VOID)ExInterlockedIncrementLong (
55: &DeviceContext->ReferenceCount,
56: &DeviceContext->Interlock);
57:
58: } /* StRefDeviceContext */
59:
60:
61: VOID
62: StDerefDeviceContext(
63: IN PDEVICE_CONTEXT DeviceContext
64: )
65:
66: /*++
67:
68: Routine Description:
69:
70: This routine dereferences a device context by decrementing the
71: reference count contained in the structure. Currently, we don't
72: do anything special when the reference count drops to zero, but
73: we could dynamically unload stuff then.
74:
75: Arguments:
76:
77: DeviceContext - Pointer to a transport device context object.
78:
79: Return Value:
80:
81: none.
82:
83: --*/
84:
85: {
86: INTERLOCKED_RESULT result;
87:
88: result = ExInterlockedDecrementLong (
89: &DeviceContext->ReferenceCount,
90: &DeviceContext->Interlock);
91:
92: ASSERT (result != ResultNegative);
93:
94: if (result == ResultZero) {
95: StDestroyDeviceContext (DeviceContext);
96: }
97:
98: } /* StDerefDeviceContext */
99:
100:
101:
102: NTSTATUS
103: StCreateDeviceContext(
104: IN PDRIVER_OBJECT DriverObject,
105: IN PUNICODE_STRING DeviceName,
106: IN OUT PDEVICE_CONTEXT *DeviceContext
107: )
108:
109: /*++
110:
111: Routine Description:
112:
113: This routine creates and initializes a device context structure.
114:
115: Arguments:
116:
117:
118: DriverObject - pointer to the IO subsystem supplied driver object.
119:
120: DeviceContext - Pointer to a pointer to a transport device context object.
121:
122: DeviceName - pointer to the name of the device this device object points to.
123:
124: Return Value:
125:
126: STATUS_SUCCESS if all is well; STATUS_INSUFFICIENT_RESOURCES otherwise.
127:
128: --*/
129:
130: {
131: NTSTATUS status;
132: PDEVICE_OBJECT deviceObject;
133: PDEVICE_CONTEXT deviceContext;
134: USHORT i;
135:
136:
137: //
138: // Create the device object for the sample transport, allowing
139: // room at the end for the device name to be stored (for use
140: // in logging errors).
141: //
142:
143: status = IoCreateDevice(
144: DriverObject,
145: sizeof (DEVICE_CONTEXT) - sizeof (DEVICE_OBJECT) +
146: (DeviceName->Length + sizeof(UNICODE_NULL)),
147: DeviceName,
148: FILE_DEVICE_TRANSPORT,
149: 0,
150: FALSE,
151: &deviceObject);
152:
153: if (!NT_SUCCESS(status)) {
154: return status;
155: }
156:
157: deviceObject->Flags |= DO_DIRECT_IO;
158:
159: deviceContext = (PDEVICE_CONTEXT)deviceObject;
160:
161: //
162: // Initialize our part of the device context.
163: //
164:
165: RtlZeroMemory(
166: ((PUCHAR)deviceContext) + sizeof(DEVICE_OBJECT),
167: sizeof(DEVICE_CONTEXT) - sizeof(DEVICE_OBJECT));
168:
169: //
170: // Copy over the device name.
171: //
172:
173: deviceContext->DeviceNameLength = DeviceName->Length + sizeof(WCHAR);
174: deviceContext->DeviceName = (PWCHAR)(deviceContext+1);
175: RtlCopyMemory(
176: deviceContext->DeviceName,
177: DeviceName->Buffer,
178: DeviceName->Length);
179: deviceContext->DeviceName[DeviceName->Length/sizeof(WCHAR)] = UNICODE_NULL;
180:
181: //
182: // Initialize the reference count.
183: //
184:
185: deviceContext->ReferenceCount = 1;
186:
187: //
188: // initialize the various fields in the device context
189: //
190:
191: KeInitializeSpinLock (&deviceContext->Interlock);
192: KeInitializeSpinLock (&deviceContext->SpinLock);
193: KeInitializeSpinLock (&deviceContext->StatisticsInterlock);
194: KeInitializeSpinLock (&deviceContext->StatisticsSpinLock);
195:
196: deviceContext->ControlChannelIdentifier = 1;
197:
198: InitializeListHead (&deviceContext->ConnectionPool);
199: InitializeListHead (&deviceContext->AddressPool);
200: InitializeListHead (&deviceContext->AddressFilePool);
201: InitializeListHead (&deviceContext->AddressDatabase);
202: InitializeListHead (&deviceContext->PacketWaitQueue);
203: InitializeListHead (&deviceContext->PacketizeQueue);
204: InitializeListHead (&deviceContext->RequestPool);
205: deviceContext->PacketPool.Next = NULL;
206: deviceContext->ReceivePacketPool.Next = NULL;
207: deviceContext->ReceiveBufferPool.Next = NULL;
208: InitializeListHead (&deviceContext->ReceiveInProgress);
209: InitializeListHead (&deviceContext->IrpCompletionQueue);
210:
211:
212: deviceContext->State = DEVICECONTEXT_STATE_CLOSED;
213:
214: //
215: // Initialize the resource that guards address ACLs.
216: //
217:
218: ExInitializeResource (&deviceContext->AddressResource);
219:
220: //
221: // set the netbios multicast address for this network type
222: //
223:
224: for (i=0; i<HARDWARE_ADDRESS_LENGTH; i++) {
225: deviceContext->LocalAddress.Address [i] = 0; // set later
226: deviceContext->MulticastAddress.Address [i] = 0;
227: }
228:
229: deviceContext->Type = ST_DEVICE_CONTEXT_SIGNATURE;
230: deviceContext->Size - sizeof (DEVICE_CONTEXT);
231:
232: *DeviceContext = deviceContext;
233: return STATUS_SUCCESS;
234: }
235:
236:
237: VOID
238: StDestroyDeviceContext(
239: IN PDEVICE_CONTEXT DeviceContext
240: )
241:
242: /*++
243:
244: Routine Description:
245:
246: This routine destroys a device context structure.
247:
248: Arguments:
249:
250: DeviceContext - Pointer to a pointer to a transport device context object.
251:
252: Return Value:
253:
254: None.
255:
256: --*/
257:
258: {
259: ExDeleteResource (&DeviceContext->AddressResource);
260: IoDeleteDevice ((PDEVICE_OBJECT)DeviceContext);
261: return;
262: }
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