1 /*
2 * An implementation of key value pair (KVP) functionality for Linux.
3 *
4 *
5 * Copyright (C) 2010, Novell, Inc.
6 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published
10 * by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
15 * NON INFRINGEMENT. See the GNU General Public License for more
16 * details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 */
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24
25 #include <linux/net.h>
26 #include <linux/nls.h>
27 #include <linux/connector.h>
28 #include <linux/workqueue.h>
29 #include <linux/hyperv.h>
30
31
32
33 /*
34 * Global state maintained for transaction that is being processed.
35 * Note that only one transaction can be active at any point in time.
36 *
37 * This state is set when we receive a request from the host; we
38 * cleanup this state when the transaction is completed - when we respond
39 * to the host with the key value.
40 */
41
42 static struct {
43 bool active; /* transaction status - active or not */
44 int recv_len; /* number of bytes received. */
45 struct hv_kvp_msg *kvp_msg; /* current message */
46 struct vmbus_channel *recv_channel; /* chn we got the request */
47 u64 recv_req_id; /* request ID. */
48 void *kvp_context; /* for the channel callback */
49 } kvp_transaction;
50
51 static void kvp_send_key(struct work_struct *dummy);
52
53 #define TIMEOUT_FIRED 1
54
55 static void kvp_respond_to_host(char *key, char *value, int error);
56 static void kvp_work_func(struct work_struct *dummy);
57 static void kvp_register(void);
58
59 static DECLARE_DELAYED_WORK(kvp_work, kvp_work_func);
60 static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
61
62 static struct cb_id kvp_id = { CN_KVP_IDX, CN_KVP_VAL };
63 static const char kvp_name[] = "kvp_kernel_module";
64 static u8 *recv_buffer;
65 /*
66 * Register the kernel component with the user-level daemon.
67 * As part of this registration, pass the LIC version number.
68 */
69
70 static void
kvp_register(void)71 kvp_register(void)
72 {
73
74 struct cn_msg *msg;
75 struct hv_kvp_msg *kvp_msg;
76 char *version;
77
78 msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg), GFP_ATOMIC);
79
80 if (msg) {
81 kvp_msg = (struct hv_kvp_msg *)msg->data;
82 version = kvp_msg->body.kvp_register.version;
83 msg->id.idx = CN_KVP_IDX;
84 msg->id.val = CN_KVP_VAL;
85
86 kvp_msg->kvp_hdr.operation = KVP_OP_REGISTER;
87 strcpy(version, HV_DRV_VERSION);
88 msg->len = sizeof(struct hv_kvp_msg);
89 cn_netlink_send(msg, 0, GFP_ATOMIC);
90 kfree(msg);
91 }
92 }
93 static void
kvp_work_func(struct work_struct * dummy)94 kvp_work_func(struct work_struct *dummy)
95 {
96 /*
97 * If the timer fires, the user-mode component has not responded;
98 * process the pending transaction.
99 */
100 kvp_respond_to_host("Unknown key", "Guest timed out", TIMEOUT_FIRED);
101 }
102
103 /*
104 * Callback when data is received from user mode.
105 */
106
107 static void
kvp_cn_callback(struct cn_msg * msg,struct netlink_skb_parms * nsp)108 kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
109 {
110 struct hv_kvp_msg *message;
111 struct hv_kvp_msg_enumerate *data;
112
113 message = (struct hv_kvp_msg *)msg->data;
114 switch (message->kvp_hdr.operation) {
115 case KVP_OP_REGISTER:
116 pr_info("KVP: user-mode registering done.\n");
117 kvp_register();
118 kvp_transaction.active = false;
119 hv_kvp_onchannelcallback(kvp_transaction.kvp_context);
120 break;
121
122 default:
123 data = &message->body.kvp_enum_data;
124 /*
125 * Complete the transaction by forwarding the key value
126 * to the host. But first, cancel the timeout.
127 */
128 if (cancel_delayed_work_sync(&kvp_work))
129 kvp_respond_to_host(data->data.key,
130 data->data.value,
131 !strlen(data->data.key));
132 }
133 }
134
135 static void
kvp_send_key(struct work_struct * dummy)136 kvp_send_key(struct work_struct *dummy)
137 {
138 struct cn_msg *msg;
139 struct hv_kvp_msg *message;
140 struct hv_kvp_msg *in_msg;
141 __u8 operation = kvp_transaction.kvp_msg->kvp_hdr.operation;
142 __u8 pool = kvp_transaction.kvp_msg->kvp_hdr.pool;
143 __u32 val32;
144 __u64 val64;
145
146 msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg) , GFP_ATOMIC);
147 if (!msg)
148 return;
149
150 msg->id.idx = CN_KVP_IDX;
151 msg->id.val = CN_KVP_VAL;
152
153 message = (struct hv_kvp_msg *)msg->data;
154 message->kvp_hdr.operation = operation;
155 message->kvp_hdr.pool = pool;
156 in_msg = kvp_transaction.kvp_msg;
157
158 /*
159 * The key/value strings sent from the host are encoded in
160 * in utf16; convert it to utf8 strings.
161 * The host assures us that the utf16 strings will not exceed
162 * the max lengths specified. We will however, reserve room
163 * for the string terminating character - in the utf16s_utf8s()
164 * function we limit the size of the buffer where the converted
165 * string is placed to HV_KVP_EXCHANGE_MAX_*_SIZE -1 to gaurantee
166 * that the strings can be properly terminated!
167 */
168
169 switch (message->kvp_hdr.operation) {
170 case KVP_OP_SET:
171 switch (in_msg->body.kvp_set.data.value_type) {
172 case REG_SZ:
173 /*
174 * The value is a string - utf16 encoding.
175 */
176 message->body.kvp_set.data.value_size =
177 utf16s_to_utf8s(
178 (wchar_t *)in_msg->body.kvp_set.data.value,
179 in_msg->body.kvp_set.data.value_size,
180 UTF16_LITTLE_ENDIAN,
181 message->body.kvp_set.data.value,
182 HV_KVP_EXCHANGE_MAX_VALUE_SIZE - 1) + 1;
183 break;
184
185 case REG_U32:
186 /*
187 * The value is a 32 bit scalar.
188 * We save this as a utf8 string.
189 */
190 val32 = in_msg->body.kvp_set.data.value_u32;
191 message->body.kvp_set.data.value_size =
192 sprintf(message->body.kvp_set.data.value,
193 "%d", val32) + 1;
194 break;
195
196 case REG_U64:
197 /*
198 * The value is a 64 bit scalar.
199 * We save this as a utf8 string.
200 */
201 val64 = in_msg->body.kvp_set.data.value_u64;
202 message->body.kvp_set.data.value_size =
203 sprintf(message->body.kvp_set.data.value,
204 "%llu", val64) + 1;
205 break;
206
207 }
208 case KVP_OP_GET:
209 message->body.kvp_set.data.key_size =
210 utf16s_to_utf8s(
211 (wchar_t *)in_msg->body.kvp_set.data.key,
212 in_msg->body.kvp_set.data.key_size,
213 UTF16_LITTLE_ENDIAN,
214 message->body.kvp_set.data.key,
215 HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
216 break;
217
218 case KVP_OP_DELETE:
219 message->body.kvp_delete.key_size =
220 utf16s_to_utf8s(
221 (wchar_t *)in_msg->body.kvp_delete.key,
222 in_msg->body.kvp_delete.key_size,
223 UTF16_LITTLE_ENDIAN,
224 message->body.kvp_delete.key,
225 HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
226 break;
227
228 case KVP_OP_ENUMERATE:
229 message->body.kvp_enum_data.index =
230 in_msg->body.kvp_enum_data.index;
231 break;
232 }
233
234 msg->len = sizeof(struct hv_kvp_msg);
235 cn_netlink_send(msg, 0, GFP_ATOMIC);
236 kfree(msg);
237
238 return;
239 }
240
241 /*
242 * Send a response back to the host.
243 */
244
245 static void
kvp_respond_to_host(char * key,char * value,int error)246 kvp_respond_to_host(char *key, char *value, int error)
247 {
248 struct hv_kvp_msg *kvp_msg;
249 struct hv_kvp_exchg_msg_value *kvp_data;
250 char *key_name;
251 struct icmsg_hdr *icmsghdrp;
252 int keylen = 0;
253 int valuelen = 0;
254 u32 buf_len;
255 struct vmbus_channel *channel;
256 u64 req_id;
257
258 /*
259 * If a transaction is not active; log and return.
260 */
261
262 if (!kvp_transaction.active) {
263 /*
264 * This is a spurious call!
265 */
266 pr_warn("KVP: Transaction not active\n");
267 return;
268 }
269 /*
270 * Copy the global state for completing the transaction. Note that
271 * only one transaction can be active at a time.
272 */
273
274 buf_len = kvp_transaction.recv_len;
275 channel = kvp_transaction.recv_channel;
276 req_id = kvp_transaction.recv_req_id;
277
278 kvp_transaction.active = false;
279
280 icmsghdrp = (struct icmsg_hdr *)
281 &recv_buffer[sizeof(struct vmbuspipe_hdr)];
282
283 if (channel->onchannel_callback == NULL)
284 /*
285 * We have raced with util driver being unloaded;
286 * silently return.
287 */
288 return;
289
290
291 /*
292 * If the error parameter is set, terminate the host's enumeration
293 * on this pool.
294 */
295 if (error) {
296 /*
297 * Something failed or the we have timedout;
298 * terminate the current host-side iteration.
299 */
300 icmsghdrp->status = HV_S_CONT;
301 goto response_done;
302 }
303
304 icmsghdrp->status = HV_S_OK;
305
306 kvp_msg = (struct hv_kvp_msg *)
307 &recv_buffer[sizeof(struct vmbuspipe_hdr) +
308 sizeof(struct icmsg_hdr)];
309
310 switch (kvp_transaction.kvp_msg->kvp_hdr.operation) {
311 case KVP_OP_GET:
312 kvp_data = &kvp_msg->body.kvp_get.data;
313 goto copy_value;
314
315 case KVP_OP_SET:
316 case KVP_OP_DELETE:
317 goto response_done;
318
319 default:
320 break;
321 }
322
323 kvp_data = &kvp_msg->body.kvp_enum_data.data;
324 key_name = key;
325
326 /*
327 * The windows host expects the key/value pair to be encoded
328 * in utf16. Ensure that the key/value size reported to the host
329 * will be less than or equal to the MAX size (including the
330 * terminating character).
331 */
332 keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN,
333 (wchar_t *) kvp_data->key,
334 (HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2) - 2);
335 kvp_data->key_size = 2*(keylen + 1); /* utf16 encoding */
336
337 copy_value:
338 valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
339 (wchar_t *) kvp_data->value,
340 (HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2) - 2);
341 kvp_data->value_size = 2*(valuelen + 1); /* utf16 encoding */
342
343 /*
344 * If the utf8s to utf16s conversion failed; notify host
345 * of the error.
346 */
347 if ((keylen < 0) || (valuelen < 0))
348 icmsghdrp->status = HV_E_FAIL;
349
350 kvp_data->value_type = REG_SZ; /* all our values are strings */
351
352 response_done:
353 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
354
355 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
356 VM_PKT_DATA_INBAND, 0);
357
358 }
359
360 /*
361 * This callback is invoked when we get a KVP message from the host.
362 * The host ensures that only one KVP transaction can be active at a time.
363 * KVP implementation in Linux needs to forward the key to a user-mde
364 * component to retrive the corresponding value. Consequently, we cannot
365 * respond to the host in the conext of this callback. Since the host
366 * guarantees that at most only one transaction can be active at a time,
367 * we stash away the transaction state in a set of global variables.
368 */
369
hv_kvp_onchannelcallback(void * context)370 void hv_kvp_onchannelcallback(void *context)
371 {
372 struct vmbus_channel *channel = context;
373 u32 recvlen;
374 u64 requestid;
375
376 struct hv_kvp_msg *kvp_msg;
377
378 struct icmsg_hdr *icmsghdrp;
379 struct icmsg_negotiate *negop = NULL;
380
381 if (kvp_transaction.active) {
382 /*
383 * We will defer processing this callback once
384 * the current transaction is complete.
385 */
386 kvp_transaction.kvp_context = context;
387 return;
388 }
389
390 vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE, &recvlen, &requestid);
391
392 if (recvlen > 0) {
393 icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
394 sizeof(struct vmbuspipe_hdr)];
395
396 if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
397 vmbus_prep_negotiate_resp(icmsghdrp, negop, recv_buffer);
398 } else {
399 kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
400 sizeof(struct vmbuspipe_hdr) +
401 sizeof(struct icmsg_hdr)];
402
403 /*
404 * Stash away this global state for completing the
405 * transaction; note transactions are serialized.
406 */
407
408 kvp_transaction.recv_len = recvlen;
409 kvp_transaction.recv_channel = channel;
410 kvp_transaction.recv_req_id = requestid;
411 kvp_transaction.active = true;
412 kvp_transaction.kvp_msg = kvp_msg;
413
414 /*
415 * Get the information from the
416 * user-mode component.
417 * component. This transaction will be
418 * completed when we get the value from
419 * the user-mode component.
420 * Set a timeout to deal with
421 * user-mode not responding.
422 */
423 schedule_work(&kvp_sendkey_work);
424 schedule_delayed_work(&kvp_work, 5*HZ);
425
426 return;
427
428 }
429
430 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
431 | ICMSGHDRFLAG_RESPONSE;
432
433 vmbus_sendpacket(channel, recv_buffer,
434 recvlen, requestid,
435 VM_PKT_DATA_INBAND, 0);
436 }
437
438 }
439
440 int
hv_kvp_init(struct hv_util_service * srv)441 hv_kvp_init(struct hv_util_service *srv)
442 {
443 int err;
444
445 err = cn_add_callback(&kvp_id, kvp_name, kvp_cn_callback);
446 if (err)
447 return err;
448 recv_buffer = srv->recv_buffer;
449
450 /*
451 * When this driver loads, the user level daemon that
452 * processes the host requests may not yet be running.
453 * Defer processing channel callbacks until the daemon
454 * has registered.
455 */
456 kvp_transaction.active = true;
457
458 return 0;
459 }
460
hv_kvp_deinit(void)461 void hv_kvp_deinit(void)
462 {
463 cn_del_callback(&kvp_id);
464 cancel_delayed_work_sync(&kvp_work);
465 cancel_work_sync(&kvp_sendkey_work);
466 }
467