Drivers: hv: Support the newly introduced KVP messages in the driver
[linux-3.10.git] / drivers / hv / hv_kvp.c
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
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
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
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
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
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          */
294         if (error) {
295                 /*
296                  * Something failed or the we have timedout;
297                  * terminate the host-side iteration by returning an error.
298                  */
299                 icmsghdrp->status = HV_E_FAIL;
300                 goto response_done;
301         }
302
303         icmsghdrp->status = HV_S_OK;
304
305         kvp_msg = (struct hv_kvp_msg *)
306                         &recv_buffer[sizeof(struct vmbuspipe_hdr) +
307                         sizeof(struct icmsg_hdr)];
308
309         switch (kvp_transaction.kvp_msg->kvp_hdr.operation) {
310         case KVP_OP_GET:
311                 kvp_data = &kvp_msg->body.kvp_get.data;
312                 goto copy_value;
313
314         case KVP_OP_SET:
315         case KVP_OP_DELETE:
316                 goto response_done;
317
318         default:
319                 break;
320         }
321
322         kvp_data = &kvp_msg->body.kvp_enum_data.data;
323         key_name = key;
324
325         /*
326          * The windows host expects the key/value pair to be encoded
327          * in utf16. Ensure that the key/value size reported to the host
328          * will be less than or equal to the MAX size (including the
329          * terminating character).
330          */
331         keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN,
332                                 (wchar_t *) kvp_data->key,
333                                 (HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2) - 2);
334         kvp_data->key_size = 2*(keylen + 1); /* utf16 encoding */
335
336 copy_value:
337         valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
338                                 (wchar_t *) kvp_data->value,
339                                 (HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2) - 2);
340         kvp_data->value_size = 2*(valuelen + 1); /* utf16 encoding */
341
342         /*
343          * If the utf8s to utf16s conversion failed; notify host
344          * of the error.
345          */
346         if ((keylen < 0) || (valuelen < 0))
347                 icmsghdrp->status = HV_E_FAIL;
348
349         kvp_data->value_type = REG_SZ; /* all our values are strings */
350
351 response_done:
352         icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
353
354         vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
355                                 VM_PKT_DATA_INBAND, 0);
356
357 }
358
359 /*
360  * This callback is invoked when we get a KVP message from the host.
361  * The host ensures that only one KVP transaction can be active at a time.
362  * KVP implementation in Linux needs to forward the key to a user-mde
363  * component to retrive the corresponding value. Consequently, we cannot
364  * respond to the host in the conext of this callback. Since the host
365  * guarantees that at most only one transaction can be active at a time,
366  * we stash away the transaction state in a set of global variables.
367  */
368
369 void hv_kvp_onchannelcallback(void *context)
370 {
371         struct vmbus_channel *channel = context;
372         u32 recvlen;
373         u64 requestid;
374
375         struct hv_kvp_msg *kvp_msg;
376
377         struct icmsg_hdr *icmsghdrp;
378         struct icmsg_negotiate *negop = NULL;
379
380         if (kvp_transaction.active) {
381                 /*
382                  * We will defer processing this callback once
383                  * the current transaction is complete.
384                  */
385                 kvp_transaction.kvp_context = context;
386                 return;
387         }
388
389         vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE, &recvlen, &requestid);
390
391         if (recvlen > 0) {
392                 icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
393                         sizeof(struct vmbuspipe_hdr)];
394
395                 if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
396                         vmbus_prep_negotiate_resp(icmsghdrp, negop, recv_buffer);
397                 } else {
398                         kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
399                                 sizeof(struct vmbuspipe_hdr) +
400                                 sizeof(struct icmsg_hdr)];
401
402                         /*
403                          * Stash away this global state for completing the
404                          * transaction; note transactions are serialized.
405                          */
406
407                         kvp_transaction.recv_len = recvlen;
408                         kvp_transaction.recv_channel = channel;
409                         kvp_transaction.recv_req_id = requestid;
410                         kvp_transaction.active = true;
411                         kvp_transaction.kvp_msg = kvp_msg;
412
413                         /*
414                          * Get the information from the
415                          * user-mode component.
416                          * component. This transaction will be
417                          * completed when we get the value from
418                          * the user-mode component.
419                          * Set a timeout to deal with
420                          * user-mode not responding.
421                          */
422                         schedule_work(&kvp_sendkey_work);
423                         schedule_delayed_work(&kvp_work, 5*HZ);
424
425                         return;
426
427                 }
428
429                 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
430                         | ICMSGHDRFLAG_RESPONSE;
431
432                 vmbus_sendpacket(channel, recv_buffer,
433                                        recvlen, requestid,
434                                        VM_PKT_DATA_INBAND, 0);
435         }
436
437 }
438
439 int
440 hv_kvp_init(struct hv_util_service *srv)
441 {
442         int err;
443
444         err = cn_add_callback(&kvp_id, kvp_name, kvp_cn_callback);
445         if (err)
446                 return err;
447         recv_buffer = srv->recv_buffer;
448
449         /*
450          * When this driver loads, the user level daemon that
451          * processes the host requests may not yet be running.
452          * Defer processing channel callbacks until the daemon
453          * has registered.
454          */
455         kvp_transaction.active = true;
456
457         return 0;
458 }
459
460 void hv_kvp_deinit(void)
461 {
462         cn_del_callback(&kvp_id);
463         cancel_delayed_work_sync(&kvp_work);
464         cancel_work_sync(&kvp_sendkey_work);
465 }