summaryrefslogtreecommitdiffstats
path: root/drivers/hv/hv_kvp.c
blob: 6186025209ce95362a42a8b6a65ad98ae99ea2c4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
/*
 * An implementation of key value pair (KVP) functionality for Linux.
 *
 *
 * Copyright (C) 2010, Novell, Inc.
 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/net.h>
#include <linux/nls.h>
#include <linux/connector.h>
#include <linux/workqueue.h>
#include <linux/hyperv.h>



/*
 * Global state maintained for transaction that is being processed.
 * Note that only one transaction can be active at any point in time.
 *
 * This state is set when we receive a request from the host; we
 * cleanup this state when the transaction is completed - when we respond
 * to the host with the key value.
 */

static struct {
	bool active; /* transaction status - active or not */
	int recv_len; /* number of bytes received. */
	struct hv_kvp_msg  *kvp_msg; /* current message */
	struct vmbus_channel *recv_channel; /* chn we got the request */
	u64 recv_req_id; /* request ID. */
	void *kvp_context; /* for the channel callback */
} kvp_transaction;

static void kvp_send_key(struct work_struct *dummy);

#define TIMEOUT_FIRED 1

static void kvp_respond_to_host(char *key, char *value, int error);
static void kvp_work_func(struct work_struct *dummy);
static void kvp_register(void);

static DECLARE_DELAYED_WORK(kvp_work, kvp_work_func);
static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);

static struct cb_id kvp_id = { CN_KVP_IDX, CN_KVP_VAL };
static const char kvp_name[] = "kvp_kernel_module";
static u8 *recv_buffer;
/*
 * Register the kernel component with the user-level daemon.
 * As part of this registration, pass the LIC version number.
 */

static void
kvp_register(void)
{

	struct cn_msg *msg;
	struct hv_kvp_msg *kvp_msg;
	char *version;

	msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg), GFP_ATOMIC);

	if (msg) {
		kvp_msg = (struct hv_kvp_msg *)msg->data;
		version = kvp_msg->body.kvp_register.version;
		msg->id.idx =  CN_KVP_IDX;
		msg->id.val = CN_KVP_VAL;

		kvp_msg->kvp_hdr.operation = KVP_OP_REGISTER;
		strcpy(version, HV_DRV_VERSION);
		msg->len = sizeof(struct hv_kvp_msg);
		cn_netlink_send(msg, 0, GFP_ATOMIC);
		kfree(msg);
	}
}
static void
kvp_work_func(struct work_struct *dummy)
{
	/*
	 * If the timer fires, the user-mode component has not responded;
	 * process the pending transaction.
	 */
	kvp_respond_to_host("Unknown key", "Guest timed out", TIMEOUT_FIRED);
}

/*
 * Callback when data is received from user mode.
 */

static void
kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
{
	struct hv_kvp_msg *message;
	struct hv_kvp_msg_enumerate *data;

	message = (struct hv_kvp_msg *)msg->data;
	switch (message->kvp_hdr.operation) {
	case KVP_OP_REGISTER:
		pr_info("KVP: user-mode registering done.\n");
		kvp_register();
		kvp_transaction.active = false;
		hv_kvp_onchannelcallback(kvp_transaction.kvp_context);
		break;

	default:
		data = &message->body.kvp_enum_data;
		/*
		 * Complete the transaction by forwarding the key value
		 * to the host. But first, cancel the timeout.
		 */
		if (cancel_delayed_work_sync(&kvp_work))
			kvp_respond_to_host(data->data.key,
					 data->data.value,
					!strlen(data->data.key));
	}
}

static void
kvp_send_key(struct work_struct *dummy)
{
	struct cn_msg *msg;
	struct hv_kvp_msg *message;
	struct hv_kvp_msg *in_msg;
	__u8 operation = kvp_transaction.kvp_msg->kvp_hdr.operation;
	__u8 pool = kvp_transaction.kvp_msg->kvp_hdr.pool;
	__u32 val32;
	__u64 val64;

	msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg) , GFP_ATOMIC);
	if (!msg)
		return;

	msg->id.idx =  CN_KVP_IDX;
	msg->id.val = CN_KVP_VAL;

	message = (struct hv_kvp_msg *)msg->data;
	message->kvp_hdr.operation = operation;
	message->kvp_hdr.pool = pool;
	in_msg = kvp_transaction.kvp_msg;

	/*
	 * The key/value strings sent from the host are encoded in
	 * in utf16; convert it to utf8 strings.
	 * The host assures us that the utf16 strings will not exceed
	 * the max lengths specified. We will however, reserve room
	 * for the string terminating character - in the utf16s_utf8s()
	 * function we limit the size of the buffer where the converted
	 * string is placed to HV_KVP_EXCHANGE_MAX_*_SIZE -1 to gaurantee
	 * that the strings can be properly terminated!
	 */

	switch (message->kvp_hdr.operation) {
	case KVP_OP_SET:
		switch (in_msg->body.kvp_set.data.value_type) {
		case REG_SZ:
			/*
			 * The value is a string - utf16 encoding.
			 */
			message->body.kvp_set.data.value_size =
				utf16s_to_utf8s(
				(wchar_t *)in_msg->body.kvp_set.data.value,
				in_msg->body.kvp_set.data.value_size,
				UTF16_LITTLE_ENDIAN,
				message->body.kvp_set.data.value,
				HV_KVP_EXCHANGE_MAX_VALUE_SIZE - 1) + 1;
				break;

		case REG_U32:
			/*
			 * The value is a 32 bit scalar.
			 * We save this as a utf8 string.
			 */
			val32 = in_msg->body.kvp_set.data.value_u32;
			message->body.kvp_set.data.value_size =
				sprintf(message->body.kvp_set.data.value,
					"%d", val32) + 1;
			break;

		case REG_U64:
			/*
			 * The value is a 64 bit scalar.
			 * We save this as a utf8 string.
			 */
			val64 = in_msg->body.kvp_set.data.value_u64;
			message->body.kvp_set.data.value_size =
				sprintf(message->body.kvp_set.data.value,
					"%llu", val64) + 1;
			break;

		}
	case KVP_OP_GET:
		message->body.kvp_set.data.key_size =
			utf16s_to_utf8s(
			(wchar_t *)in_msg->body.kvp_set.data.key,
			in_msg->body.kvp_set.data.key_size,
			UTF16_LITTLE_ENDIAN,
			message->body.kvp_set.data.key,
			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
			break;

	case KVP_OP_DELETE:
		message->body.kvp_delete.key_size =
			utf16s_to_utf8s(
			(wchar_t *)in_msg->body.kvp_delete.key,
			in_msg->body.kvp_delete.key_size,
			UTF16_LITTLE_ENDIAN,
			message->body.kvp_delete.key,
			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
			break;

	case KVP_OP_ENUMERATE:
		message->body.kvp_enum_data.index =
			in_msg->body.kvp_enum_data.index;
			break;
	}

	msg->len = sizeof(struct hv_kvp_msg);
	cn_netlink_send(msg, 0, GFP_ATOMIC);
	kfree(msg);

	return;
}

/*
 * Send a response back to the host.
 */

static void
kvp_respond_to_host(char *key, char *value, int error)
{
	struct hv_kvp_msg  *kvp_msg;
	struct hv_kvp_exchg_msg_value  *kvp_data;
	char	*key_name;
	struct icmsg_hdr *icmsghdrp;
	int	keylen = 0;
	int	valuelen = 0;
	u32	buf_len;
	struct vmbus_channel *channel;
	u64	req_id;

	/*
	 * If a transaction is not active; log and return.
	 */

	if (!kvp_transaction.active) {
		/*
		 * This is a spurious call!
		 */
		pr_warn("KVP: Transaction not active\n");
		return;
	}
	/*
	 * Copy the global state for completing the transaction. Note that
	 * only one transaction can be active at a time.
	 */

	buf_len = kvp_transaction.recv_len;
	channel = kvp_transaction.recv_channel;
	req_id = kvp_transaction.recv_req_id;

	kvp_transaction.active = false;

	icmsghdrp = (struct icmsg_hdr *)
			&recv_buffer[sizeof(struct vmbuspipe_hdr)];

	if (channel->onchannel_callback == NULL)
		/*
		 * We have raced with util driver being unloaded;
		 * silently return.
		 */
		return;


	/*
	 * If the error parameter is set, terminate the host's enumeration
	 * on this pool.
	 */
	if (error) {
		/*
		 * Something failed or the we have timedout;
		 * terminate the current  host-side iteration.
		 */
		icmsghdrp->status = HV_S_CONT;
		goto response_done;
	}

	icmsghdrp->status = HV_S_OK;

	kvp_msg = (struct hv_kvp_msg *)
			&recv_buffer[sizeof(struct vmbuspipe_hdr) +
			sizeof(struct icmsg_hdr)];

	switch (kvp_transaction.kvp_msg->kvp_hdr.operation) {
	case KVP_OP_GET:
		kvp_data = &kvp_msg->body.kvp_get.data;
		goto copy_value;

	case KVP_OP_SET:
	case KVP_OP_DELETE:
		goto response_done;

	default:
		break;
	}

	kvp_data = &kvp_msg->body.kvp_enum_data.data;
	key_name = key;

	/*
	 * The windows host expects the key/value pair to be encoded
	 * in utf16. Ensure that the key/value size reported to the host
	 * will be less than or equal to the MAX size (including the
	 * terminating character).
	 */
	keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN,
				(wchar_t *) kvp_data->key,
				(HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2) - 2);
	kvp_data->key_size = 2*(keylen + 1); /* utf16 encoding */

copy_value:
	valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
				(wchar_t *) kvp_data->value,
				(HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2) - 2);
	kvp_data->value_size = 2*(valuelen + 1); /* utf16 encoding */

	/*
	 * If the utf8s to utf16s conversion failed; notify host
	 * of the error.
	 */
	if ((keylen < 0) || (valuelen < 0))
		icmsghdrp->status = HV_E_FAIL;

	kvp_data->value_type = REG_SZ; /* all our values are strings */

response_done:
	icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;

	vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
				VM_PKT_DATA_INBAND, 0);

}

/*
 * This callback is invoked when we get a KVP message from the host.
 * The host ensures that only one KVP transaction can be active at a time.
 * KVP implementation in Linux needs to forward the key to a user-mde
 * component to retrive the corresponding value. Consequently, we cannot
 * respond to the host in the conext of this callback. Since the host
 * guarantees that at most only one transaction can be active at a time,
 * we stash away the transaction state in a set of global variables.
 */

void hv_kvp_onchannelcallback(void *context)
{
	struct vmbus_channel *channel = context;
	u32 recvlen;
	u64 requestid;

	struct hv_kvp_msg *kvp_msg;

	struct icmsg_hdr *icmsghdrp;
	struct icmsg_negotiate *negop = NULL;

	if (kvp_transaction.active) {
		/*
		 * We will defer processing this callback once
		 * the current transaction is complete.
		 */
		kvp_transaction.kvp_context = context;
		return;
	}

	vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE, &recvlen, &requestid);

	if (recvlen > 0) {
		icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
			sizeof(struct vmbuspipe_hdr)];

		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
			vmbus_prep_negotiate_resp(icmsghdrp, negop, recv_buffer);
		} else {
			kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
				sizeof(struct vmbuspipe_hdr) +
				sizeof(struct icmsg_hdr)];

			/*
			 * Stash away this global state for completing the
			 * transaction; note transactions are serialized.
			 */

			kvp_transaction.recv_len = recvlen;
			kvp_transaction.recv_channel = channel;
			kvp_transaction.recv_req_id = requestid;
			kvp_transaction.active = true;
			kvp_transaction.kvp_msg = kvp_msg;

			/*
			 * Get the information from the
			 * user-mode component.
			 * component. This transaction will be
			 * completed when we get the value from
			 * the user-mode component.
			 * Set a timeout to deal with
			 * user-mode not responding.
			 */
			schedule_work(&kvp_sendkey_work);
			schedule_delayed_work(&kvp_work, 5*HZ);

			return;

		}

		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
			| ICMSGHDRFLAG_RESPONSE;

		vmbus_sendpacket(channel, recv_buffer,
				       recvlen, requestid,
				       VM_PKT_DATA_INBAND, 0);
	}

}

int
hv_kvp_init(struct hv_util_service *srv)
{
	int err;

	err = cn_add_callback(&kvp_id, kvp_name, kvp_cn_callback);
	if (err)
		return err;
	recv_buffer = srv->recv_buffer;

	/*
	 * When this driver loads, the user level daemon that
	 * processes the host requests may not yet be running.
	 * Defer processing channel callbacks until the daemon
	 * has registered.
	 */
	kvp_transaction.active = true;

	return 0;
}

void hv_kvp_deinit(void)
{
	cn_del_callback(&kvp_id);
	cancel_delayed_work_sync(&kvp_work);
	cancel_work_sync(&kvp_sendkey_work);
}