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 #include "hv_kvp.h"
32
33
34
35 /*
36 * Global state maintained for transaction that is being processed.
37 * Note that only one transaction can be active at any point in time.
38 *
39 * This state is set when we receive a request from the host; we
40 * cleanup this state when the transaction is completed - when we respond
41 * to the host with the key value.
42 */
43
44 static struct {
45 bool active; /* transaction status - active or not */
46 int recv_len; /* number of bytes received. */
47 int index; /* current index */
48 struct vmbus_channel *recv_channel; /* chn we got the request */
49 u64 recv_req_id; /* request ID. */
50 } kvp_transaction;
51
52 static void kvp_send_key(struct work_struct *dummy);
53
54 #define TIMEOUT_FIRED 1
55
56 static void kvp_respond_to_host(char *key, char *value, int error);
57 static void kvp_work_func(struct work_struct *dummy);
58 static void kvp_register(void);
59
60 static DECLARE_DELAYED_WORK(kvp_work, kvp_work_func);
61 static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
62
63 static struct cb_id kvp_id = { CN_KVP_IDX, CN_KVP_VAL };
64 static const char kvp_name[] = "kvp_kernel_module";
65 static u8 *recv_buffer;
66 /*
67 * Register the kernel component with the user-level daemon.
68 * As part of this registration, pass the LIC version number.
69 */
70
71 static void
kvp_register(void)72 kvp_register(void)
73 {
74
75 struct cn_msg *msg;
76
77 msg = kzalloc(sizeof(*msg) + strlen(HV_DRV_VERSION) + 1 , GFP_ATOMIC);
78
79 if (msg) {
80 msg->id.idx = CN_KVP_IDX;
81 msg->id.val = CN_KVP_VAL;
82 msg->seq = KVP_REGISTER;
83 strcpy(msg->data, HV_DRV_VERSION);
84 msg->len = strlen(HV_DRV_VERSION) + 1;
85 cn_netlink_send(msg, 0, GFP_ATOMIC);
86 kfree(msg);
87 }
88 }
89 static void
kvp_work_func(struct work_struct * dummy)90 kvp_work_func(struct work_struct *dummy)
91 {
92 /*
93 * If the timer fires, the user-mode component has not responded;
94 * process the pending transaction.
95 */
96 kvp_respond_to_host("Unknown key", "Guest timed out", TIMEOUT_FIRED);
97 }
98
99 /*
100 * Callback when data is received from user mode.
101 */
102
103 static void
kvp_cn_callback(struct cn_msg * msg,struct netlink_skb_parms * nsp)104 kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
105 {
106 struct hv_ku_msg *message;
107
108 message = (struct hv_ku_msg *)msg->data;
109 if (msg->seq == KVP_REGISTER) {
110 pr_info("KVP: user-mode registering done.\n");
111 kvp_register();
112 }
113
114 if (msg->seq == KVP_USER_SET) {
115 /*
116 * Complete the transaction by forwarding the key value
117 * to the host. But first, cancel the timeout.
118 */
119 if (cancel_delayed_work_sync(&kvp_work))
120 kvp_respond_to_host(message->kvp_key,
121 message->kvp_value,
122 !strlen(message->kvp_key));
123 }
124 }
125
126 static void
kvp_send_key(struct work_struct * dummy)127 kvp_send_key(struct work_struct *dummy)
128 {
129 struct cn_msg *msg;
130 int index = kvp_transaction.index;
131
132 msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg) , GFP_ATOMIC);
133
134 if (msg) {
135 msg->id.idx = CN_KVP_IDX;
136 msg->id.val = CN_KVP_VAL;
137 msg->seq = KVP_KERNEL_GET;
138 ((struct hv_ku_msg *)msg->data)->kvp_index = index;
139 msg->len = sizeof(struct hv_ku_msg);
140 cn_netlink_send(msg, 0, GFP_ATOMIC);
141 kfree(msg);
142 }
143 return;
144 }
145
146 /*
147 * Send a response back to the host.
148 */
149
150 static void
kvp_respond_to_host(char * key,char * value,int error)151 kvp_respond_to_host(char *key, char *value, int error)
152 {
153 struct hv_kvp_msg *kvp_msg;
154 struct hv_kvp_msg_enumerate *kvp_data;
155 char *key_name;
156 struct icmsg_hdr *icmsghdrp;
157 int keylen, valuelen;
158 u32 buf_len;
159 struct vmbus_channel *channel;
160 u64 req_id;
161
162 /*
163 * If a transaction is not active; log and return.
164 */
165
166 if (!kvp_transaction.active) {
167 /*
168 * This is a spurious call!
169 */
170 pr_warn("KVP: Transaction not active\n");
171 return;
172 }
173 /*
174 * Copy the global state for completing the transaction. Note that
175 * only one transaction can be active at a time.
176 */
177
178 buf_len = kvp_transaction.recv_len;
179 channel = kvp_transaction.recv_channel;
180 req_id = kvp_transaction.recv_req_id;
181
182 kvp_transaction.active = false;
183
184 if (channel->onchannel_callback == NULL)
185 /*
186 * We have raced with util driver being unloaded;
187 * silently return.
188 */
189 return;
190
191 icmsghdrp = (struct icmsg_hdr *)
192 &recv_buffer[sizeof(struct vmbuspipe_hdr)];
193 kvp_msg = (struct hv_kvp_msg *)
194 &recv_buffer[sizeof(struct vmbuspipe_hdr) +
195 sizeof(struct icmsg_hdr)];
196 kvp_data = &kvp_msg->kvp_data;
197 key_name = key;
198
199 /*
200 * If the error parameter is set, terminate the host's enumeration.
201 */
202 if (error) {
203 /*
204 * We don't support this index or the we have timedout;
205 * terminate the host-side iteration by returning an error.
206 */
207 icmsghdrp->status = HV_E_FAIL;
208 goto response_done;
209 }
210
211 /*
212 * The windows host expects the key/value pair to be encoded
213 * in utf16.
214 */
215 keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN,
216 (wchar_t *) kvp_data->data.key,
217 HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2);
218 kvp_data->data.key_size = 2*(keylen + 1); /* utf16 encoding */
219 valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
220 (wchar_t *) kvp_data->data.value,
221 HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2);
222 kvp_data->data.value_size = 2*(valuelen + 1); /* utf16 encoding */
223
224 kvp_data->data.value_type = REG_SZ; /* all our values are strings */
225 icmsghdrp->status = HV_S_OK;
226
227 response_done:
228 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
229
230 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
231 VM_PKT_DATA_INBAND, 0);
232
233 }
234
235 /*
236 * This callback is invoked when we get a KVP message from the host.
237 * The host ensures that only one KVP transaction can be active at a time.
238 * KVP implementation in Linux needs to forward the key to a user-mde
239 * component to retrive the corresponding value. Consequently, we cannot
240 * respond to the host in the conext of this callback. Since the host
241 * guarantees that at most only one transaction can be active at a time,
242 * we stash away the transaction state in a set of global variables.
243 */
244
hv_kvp_onchannelcallback(void * context)245 void hv_kvp_onchannelcallback(void *context)
246 {
247 struct vmbus_channel *channel = context;
248 u32 recvlen;
249 u64 requestid;
250
251 struct hv_kvp_msg *kvp_msg;
252 struct hv_kvp_msg_enumerate *kvp_data;
253
254 struct icmsg_hdr *icmsghdrp;
255 struct icmsg_negotiate *negop = NULL;
256
257
258 vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE, &recvlen, &requestid);
259
260 if (recvlen > 0) {
261 icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
262 sizeof(struct vmbuspipe_hdr)];
263
264 if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
265 vmbus_prep_negotiate_resp(icmsghdrp, negop, recv_buffer);
266 } else {
267 kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
268 sizeof(struct vmbuspipe_hdr) +
269 sizeof(struct icmsg_hdr)];
270
271 kvp_data = &kvp_msg->kvp_data;
272
273 /*
274 * We only support the "get" operation on
275 * "KVP_POOL_AUTO" pool.
276 */
277
278 if ((kvp_msg->kvp_hdr.pool != KVP_POOL_AUTO) ||
279 (kvp_msg->kvp_hdr.operation !=
280 KVP_OP_ENUMERATE)) {
281 icmsghdrp->status = HV_E_FAIL;
282 goto callback_done;
283 }
284
285 /*
286 * Stash away this global state for completing the
287 * transaction; note transactions are serialized.
288 */
289 kvp_transaction.recv_len = recvlen;
290 kvp_transaction.recv_channel = channel;
291 kvp_transaction.recv_req_id = requestid;
292 kvp_transaction.active = true;
293 kvp_transaction.index = kvp_data->index;
294
295 /*
296 * Get the information from the
297 * user-mode component.
298 * component. This transaction will be
299 * completed when we get the value from
300 * the user-mode component.
301 * Set a timeout to deal with
302 * user-mode not responding.
303 */
304 schedule_work(&kvp_sendkey_work);
305 schedule_delayed_work(&kvp_work, 5*HZ);
306
307 return;
308
309 }
310
311 callback_done:
312
313 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
314 | ICMSGHDRFLAG_RESPONSE;
315
316 vmbus_sendpacket(channel, recv_buffer,
317 recvlen, requestid,
318 VM_PKT_DATA_INBAND, 0);
319 }
320
321 }
322
323 int
hv_kvp_init(struct hv_util_service * srv)324 hv_kvp_init(struct hv_util_service *srv)
325 {
326 int err;
327
328 err = cn_add_callback(&kvp_id, kvp_name, kvp_cn_callback);
329 if (err)
330 return err;
331 recv_buffer = srv->recv_buffer;
332
333 return 0;
334 }
335
hv_kvp_deinit(void)336 void hv_kvp_deinit(void)
337 {
338 cn_del_callback(&kvp_id);
339 cancel_delayed_work_sync(&kvp_work);
340 cancel_work_sync(&kvp_sendkey_work);
341 }
342