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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 "hyperv_vmbus.h"
32 #include "hv_utils_transport.h"
33 
34 /*
35  * Pre win8 version numbers used in ws2008 and ws 2008 r2 (win7)
36  */
37 #define WS2008_SRV_MAJOR	1
38 #define WS2008_SRV_MINOR	0
39 #define WS2008_SRV_VERSION     (WS2008_SRV_MAJOR << 16 | WS2008_SRV_MINOR)
40 
41 #define WIN7_SRV_MAJOR   3
42 #define WIN7_SRV_MINOR   0
43 #define WIN7_SRV_VERSION     (WIN7_SRV_MAJOR << 16 | WIN7_SRV_MINOR)
44 
45 #define WIN8_SRV_MAJOR   4
46 #define WIN8_SRV_MINOR   0
47 #define WIN8_SRV_VERSION     (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)
48 
49 #define KVP_VER_COUNT 3
50 static const int kvp_versions[] = {
51 	WIN8_SRV_VERSION,
52 	WIN7_SRV_VERSION,
53 	WS2008_SRV_VERSION
54 };
55 
56 #define FW_VER_COUNT 2
57 static const int fw_versions[] = {
58 	UTIL_FW_VERSION,
59 	UTIL_WS2K8_FW_VERSION
60 };
61 
62 /*
63  * Global state maintained for transaction that is being processed. For a class
64  * of integration services, including the "KVP service", the specified protocol
65  * is a "request/response" protocol which means that there can only be single
66  * outstanding transaction from the host at any given point in time. We use
67  * this to simplify memory management in this driver - we cache and process
68  * only one message at a time.
69  *
70  * While the request/response protocol is guaranteed by the host, we further
71  * ensure this by serializing packet processing in this driver - we do not
72  * read additional packets from the VMBUS until the current packet is fully
73  * handled.
74  */
75 
76 static struct {
77 	int state;   /* hvutil_device_state */
78 	int recv_len; /* number of bytes received. */
79 	struct hv_kvp_msg  *kvp_msg; /* current message */
80 	struct vmbus_channel *recv_channel; /* chn we got the request */
81 	u64 recv_req_id; /* request ID. */
82 } kvp_transaction;
83 
84 /*
85  * This state maintains the version number registered by the daemon.
86  */
87 static int dm_reg_value;
88 
89 static void kvp_send_key(struct work_struct *dummy);
90 
91 
92 static void kvp_respond_to_host(struct hv_kvp_msg *msg, int error);
93 static void kvp_timeout_func(struct work_struct *dummy);
94 static void kvp_host_handshake_func(struct work_struct *dummy);
95 static void kvp_register(int);
96 
97 static DECLARE_DELAYED_WORK(kvp_timeout_work, kvp_timeout_func);
98 static DECLARE_DELAYED_WORK(kvp_host_handshake_work, kvp_host_handshake_func);
99 static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
100 
101 static const char kvp_devname[] = "vmbus/hv_kvp";
102 static u8 *recv_buffer;
103 static struct hvutil_transport *hvt;
104 /*
105  * Register the kernel component with the user-level daemon.
106  * As part of this registration, pass the LIC version number.
107  * This number has no meaning, it satisfies the registration protocol.
108  */
109 #define HV_DRV_VERSION           "3.1"
110 
kvp_poll_wrapper(void * channel)111 static void kvp_poll_wrapper(void *channel)
112 {
113 	/* Transaction is finished, reset the state here to avoid races. */
114 	kvp_transaction.state = HVUTIL_READY;
115 	tasklet_schedule(&((struct vmbus_channel *)channel)->callback_event);
116 }
117 
kvp_register_done(void)118 static void kvp_register_done(void)
119 {
120 	/*
121 	 * If we're still negotiating with the host cancel the timeout
122 	 * work to not poll the channel twice.
123 	 */
124 	pr_debug("KVP: userspace daemon registered\n");
125 	cancel_delayed_work_sync(&kvp_host_handshake_work);
126 	hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
127 }
128 
129 static void
kvp_register(int reg_value)130 kvp_register(int reg_value)
131 {
132 
133 	struct hv_kvp_msg *kvp_msg;
134 	char *version;
135 
136 	kvp_msg = kzalloc(sizeof(*kvp_msg), GFP_KERNEL);
137 
138 	if (kvp_msg) {
139 		version = kvp_msg->body.kvp_register.version;
140 		kvp_msg->kvp_hdr.operation = reg_value;
141 		strcpy(version, HV_DRV_VERSION);
142 
143 		hvutil_transport_send(hvt, kvp_msg, sizeof(*kvp_msg),
144 				      kvp_register_done);
145 		kfree(kvp_msg);
146 	}
147 }
148 
kvp_timeout_func(struct work_struct * dummy)149 static void kvp_timeout_func(struct work_struct *dummy)
150 {
151 	/*
152 	 * If the timer fires, the user-mode component has not responded;
153 	 * process the pending transaction.
154 	 */
155 	kvp_respond_to_host(NULL, HV_E_FAIL);
156 
157 	hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
158 }
159 
kvp_host_handshake_func(struct work_struct * dummy)160 static void kvp_host_handshake_func(struct work_struct *dummy)
161 {
162 	tasklet_schedule(&kvp_transaction.recv_channel->callback_event);
163 }
164 
kvp_handle_handshake(struct hv_kvp_msg * msg)165 static int kvp_handle_handshake(struct hv_kvp_msg *msg)
166 {
167 	switch (msg->kvp_hdr.operation) {
168 	case KVP_OP_REGISTER:
169 		dm_reg_value = KVP_OP_REGISTER;
170 		pr_info("KVP: IP injection functionality not available\n");
171 		pr_info("KVP: Upgrade the KVP daemon\n");
172 		break;
173 	case KVP_OP_REGISTER1:
174 		dm_reg_value = KVP_OP_REGISTER1;
175 		break;
176 	default:
177 		pr_info("KVP: incompatible daemon\n");
178 		pr_info("KVP: KVP version: %d, Daemon version: %d\n",
179 			KVP_OP_REGISTER1, msg->kvp_hdr.operation);
180 		return -EINVAL;
181 	}
182 
183 	/*
184 	 * We have a compatible daemon; complete the handshake.
185 	 */
186 	pr_debug("KVP: userspace daemon ver. %d connected\n",
187 		 msg->kvp_hdr.operation);
188 	kvp_register(dm_reg_value);
189 
190 	return 0;
191 }
192 
193 
194 /*
195  * Callback when data is received from user mode.
196  */
197 
kvp_on_msg(void * msg,int len)198 static int kvp_on_msg(void *msg, int len)
199 {
200 	struct hv_kvp_msg *message = (struct hv_kvp_msg *)msg;
201 	struct hv_kvp_msg_enumerate *data;
202 	int	error = 0;
203 
204 	if (len < sizeof(*message))
205 		return -EINVAL;
206 
207 	/*
208 	 * If we are negotiating the version information
209 	 * with the daemon; handle that first.
210 	 */
211 
212 	if (kvp_transaction.state < HVUTIL_READY) {
213 		return kvp_handle_handshake(message);
214 	}
215 
216 	/* We didn't send anything to userspace so the reply is spurious */
217 	if (kvp_transaction.state < HVUTIL_USERSPACE_REQ)
218 		return -EINVAL;
219 
220 	kvp_transaction.state = HVUTIL_USERSPACE_RECV;
221 
222 	/*
223 	 * Based on the version of the daemon, we propagate errors from the
224 	 * daemon differently.
225 	 */
226 
227 	data = &message->body.kvp_enum_data;
228 
229 	switch (dm_reg_value) {
230 	case KVP_OP_REGISTER:
231 		/*
232 		 * Null string is used to pass back error condition.
233 		 */
234 		if (data->data.key[0] == 0)
235 			error = HV_S_CONT;
236 		break;
237 
238 	case KVP_OP_REGISTER1:
239 		/*
240 		 * We use the message header information from
241 		 * the user level daemon to transmit errors.
242 		 */
243 		error = message->error;
244 		break;
245 	}
246 
247 	/*
248 	 * Complete the transaction by forwarding the key value
249 	 * to the host. But first, cancel the timeout.
250 	 */
251 	if (cancel_delayed_work_sync(&kvp_timeout_work)) {
252 		kvp_respond_to_host(message, error);
253 		hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
254 	}
255 
256 	return 0;
257 }
258 
259 
process_ob_ipinfo(void * in_msg,void * out_msg,int op)260 static int process_ob_ipinfo(void *in_msg, void *out_msg, int op)
261 {
262 	struct hv_kvp_msg *in = in_msg;
263 	struct hv_kvp_ip_msg *out = out_msg;
264 	int len;
265 
266 	switch (op) {
267 	case KVP_OP_GET_IP_INFO:
268 		/*
269 		 * Transform all parameters into utf16 encoding.
270 		 */
271 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.ip_addr,
272 				strlen((char *)in->body.kvp_ip_val.ip_addr),
273 				UTF16_HOST_ENDIAN,
274 				(wchar_t *)out->kvp_ip_val.ip_addr,
275 				MAX_IP_ADDR_SIZE);
276 		if (len < 0)
277 			return len;
278 
279 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.sub_net,
280 				strlen((char *)in->body.kvp_ip_val.sub_net),
281 				UTF16_HOST_ENDIAN,
282 				(wchar_t *)out->kvp_ip_val.sub_net,
283 				MAX_IP_ADDR_SIZE);
284 		if (len < 0)
285 			return len;
286 
287 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.gate_way,
288 				strlen((char *)in->body.kvp_ip_val.gate_way),
289 				UTF16_HOST_ENDIAN,
290 				(wchar_t *)out->kvp_ip_val.gate_way,
291 				MAX_GATEWAY_SIZE);
292 		if (len < 0)
293 			return len;
294 
295 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.dns_addr,
296 				strlen((char *)in->body.kvp_ip_val.dns_addr),
297 				UTF16_HOST_ENDIAN,
298 				(wchar_t *)out->kvp_ip_val.dns_addr,
299 				MAX_IP_ADDR_SIZE);
300 		if (len < 0)
301 			return len;
302 
303 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.adapter_id,
304 				strlen((char *)in->body.kvp_ip_val.adapter_id),
305 				UTF16_HOST_ENDIAN,
306 				(wchar_t *)out->kvp_ip_val.adapter_id,
307 				MAX_ADAPTER_ID_SIZE);
308 		if (len < 0)
309 			return len;
310 
311 		out->kvp_ip_val.dhcp_enabled =
312 			in->body.kvp_ip_val.dhcp_enabled;
313 		out->kvp_ip_val.addr_family =
314 			in->body.kvp_ip_val.addr_family;
315 	}
316 
317 	return 0;
318 }
319 
process_ib_ipinfo(void * in_msg,void * out_msg,int op)320 static void process_ib_ipinfo(void *in_msg, void *out_msg, int op)
321 {
322 	struct hv_kvp_ip_msg *in = in_msg;
323 	struct hv_kvp_msg *out = out_msg;
324 
325 	switch (op) {
326 	case KVP_OP_SET_IP_INFO:
327 		/*
328 		 * Transform all parameters into utf8 encoding.
329 		 */
330 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.ip_addr,
331 				MAX_IP_ADDR_SIZE,
332 				UTF16_LITTLE_ENDIAN,
333 				(__u8 *)out->body.kvp_ip_val.ip_addr,
334 				MAX_IP_ADDR_SIZE);
335 
336 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.sub_net,
337 				MAX_IP_ADDR_SIZE,
338 				UTF16_LITTLE_ENDIAN,
339 				(__u8 *)out->body.kvp_ip_val.sub_net,
340 				MAX_IP_ADDR_SIZE);
341 
342 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.gate_way,
343 				MAX_GATEWAY_SIZE,
344 				UTF16_LITTLE_ENDIAN,
345 				(__u8 *)out->body.kvp_ip_val.gate_way,
346 				MAX_GATEWAY_SIZE);
347 
348 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.dns_addr,
349 				MAX_IP_ADDR_SIZE,
350 				UTF16_LITTLE_ENDIAN,
351 				(__u8 *)out->body.kvp_ip_val.dns_addr,
352 				MAX_IP_ADDR_SIZE);
353 
354 		out->body.kvp_ip_val.dhcp_enabled = in->kvp_ip_val.dhcp_enabled;
355 
356 		/* fallthrough */
357 
358 	case KVP_OP_GET_IP_INFO:
359 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.adapter_id,
360 				MAX_ADAPTER_ID_SIZE,
361 				UTF16_LITTLE_ENDIAN,
362 				(__u8 *)out->body.kvp_ip_val.adapter_id,
363 				MAX_ADAPTER_ID_SIZE);
364 
365 		out->body.kvp_ip_val.addr_family = in->kvp_ip_val.addr_family;
366 	}
367 }
368 
369 
370 
371 
372 static void
kvp_send_key(struct work_struct * dummy)373 kvp_send_key(struct work_struct *dummy)
374 {
375 	struct hv_kvp_msg *message;
376 	struct hv_kvp_msg *in_msg;
377 	__u8 operation = kvp_transaction.kvp_msg->kvp_hdr.operation;
378 	__u8 pool = kvp_transaction.kvp_msg->kvp_hdr.pool;
379 	__u32 val32;
380 	__u64 val64;
381 	int rc;
382 
383 	/* The transaction state is wrong. */
384 	if (kvp_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
385 		return;
386 
387 	message = kzalloc(sizeof(*message), GFP_KERNEL);
388 	if (!message)
389 		return;
390 
391 	message->kvp_hdr.operation = operation;
392 	message->kvp_hdr.pool = pool;
393 	in_msg = kvp_transaction.kvp_msg;
394 
395 	/*
396 	 * The key/value strings sent from the host are encoded in
397 	 * in utf16; convert it to utf8 strings.
398 	 * The host assures us that the utf16 strings will not exceed
399 	 * the max lengths specified. We will however, reserve room
400 	 * for the string terminating character - in the utf16s_utf8s()
401 	 * function we limit the size of the buffer where the converted
402 	 * string is placed to HV_KVP_EXCHANGE_MAX_*_SIZE -1 to guarantee
403 	 * that the strings can be properly terminated!
404 	 */
405 
406 	switch (message->kvp_hdr.operation) {
407 	case KVP_OP_SET_IP_INFO:
408 		process_ib_ipinfo(in_msg, message, KVP_OP_SET_IP_INFO);
409 		break;
410 	case KVP_OP_GET_IP_INFO:
411 		/*
412 		 * We only need to pass on the info of operation, adapter_id
413 		 * and addr_family to the userland kvp daemon.
414 		 */
415 		process_ib_ipinfo(in_msg, message, KVP_OP_GET_IP_INFO);
416 		break;
417 	case KVP_OP_SET:
418 		switch (in_msg->body.kvp_set.data.value_type) {
419 		case REG_SZ:
420 			/*
421 			 * The value is a string - utf16 encoding.
422 			 */
423 			message->body.kvp_set.data.value_size =
424 				utf16s_to_utf8s(
425 				(wchar_t *)in_msg->body.kvp_set.data.value,
426 				in_msg->body.kvp_set.data.value_size,
427 				UTF16_LITTLE_ENDIAN,
428 				message->body.kvp_set.data.value,
429 				HV_KVP_EXCHANGE_MAX_VALUE_SIZE - 1) + 1;
430 			break;
431 
432 		case REG_U32:
433 			/*
434 			 * The value is a 32 bit scalar.
435 			 * We save this as a utf8 string.
436 			 */
437 			val32 = in_msg->body.kvp_set.data.value_u32;
438 			message->body.kvp_set.data.value_size =
439 				sprintf(message->body.kvp_set.data.value,
440 					"%u", val32) + 1;
441 			break;
442 
443 		case REG_U64:
444 			/*
445 			 * The value is a 64 bit scalar.
446 			 * We save this as a utf8 string.
447 			 */
448 			val64 = in_msg->body.kvp_set.data.value_u64;
449 			message->body.kvp_set.data.value_size =
450 				sprintf(message->body.kvp_set.data.value,
451 					"%llu", val64) + 1;
452 			break;
453 
454 		}
455 
456 		/*
457 		 * The key is always a string - utf16 encoding.
458 		 */
459 		message->body.kvp_set.data.key_size =
460 			utf16s_to_utf8s(
461 			(wchar_t *)in_msg->body.kvp_set.data.key,
462 			in_msg->body.kvp_set.data.key_size,
463 			UTF16_LITTLE_ENDIAN,
464 			message->body.kvp_set.data.key,
465 			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
466 
467 		break;
468 
469 	case KVP_OP_GET:
470 		message->body.kvp_get.data.key_size =
471 			utf16s_to_utf8s(
472 			(wchar_t *)in_msg->body.kvp_get.data.key,
473 			in_msg->body.kvp_get.data.key_size,
474 			UTF16_LITTLE_ENDIAN,
475 			message->body.kvp_get.data.key,
476 			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
477 		break;
478 
479 	case KVP_OP_DELETE:
480 		message->body.kvp_delete.key_size =
481 			utf16s_to_utf8s(
482 			(wchar_t *)in_msg->body.kvp_delete.key,
483 			in_msg->body.kvp_delete.key_size,
484 			UTF16_LITTLE_ENDIAN,
485 			message->body.kvp_delete.key,
486 			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
487 		break;
488 
489 	case KVP_OP_ENUMERATE:
490 		message->body.kvp_enum_data.index =
491 			in_msg->body.kvp_enum_data.index;
492 		break;
493 	}
494 
495 	kvp_transaction.state = HVUTIL_USERSPACE_REQ;
496 	rc = hvutil_transport_send(hvt, message, sizeof(*message), NULL);
497 	if (rc) {
498 		pr_debug("KVP: failed to communicate to the daemon: %d\n", rc);
499 		if (cancel_delayed_work_sync(&kvp_timeout_work)) {
500 			kvp_respond_to_host(message, HV_E_FAIL);
501 			kvp_transaction.state = HVUTIL_READY;
502 		}
503 	}
504 
505 	kfree(message);
506 }
507 
508 /*
509  * Send a response back to the host.
510  */
511 
512 static void
kvp_respond_to_host(struct hv_kvp_msg * msg_to_host,int error)513 kvp_respond_to_host(struct hv_kvp_msg *msg_to_host, int error)
514 {
515 	struct hv_kvp_msg  *kvp_msg;
516 	struct hv_kvp_exchg_msg_value  *kvp_data;
517 	char	*key_name;
518 	char	*value;
519 	struct icmsg_hdr *icmsghdrp;
520 	int	keylen = 0;
521 	int	valuelen = 0;
522 	u32	buf_len;
523 	struct vmbus_channel *channel;
524 	u64	req_id;
525 	int ret;
526 
527 	/*
528 	 * Copy the global state for completing the transaction. Note that
529 	 * only one transaction can be active at a time.
530 	 */
531 
532 	buf_len = kvp_transaction.recv_len;
533 	channel = kvp_transaction.recv_channel;
534 	req_id = kvp_transaction.recv_req_id;
535 
536 	icmsghdrp = (struct icmsg_hdr *)
537 			&recv_buffer[sizeof(struct vmbuspipe_hdr)];
538 
539 	if (channel->onchannel_callback == NULL)
540 		/*
541 		 * We have raced with util driver being unloaded;
542 		 * silently return.
543 		 */
544 		return;
545 
546 	icmsghdrp->status = error;
547 
548 	/*
549 	 * If the error parameter is set, terminate the host's enumeration
550 	 * on this pool.
551 	 */
552 	if (error) {
553 		/*
554 		 * Something failed or we have timed out;
555 		 * terminate the current host-side iteration.
556 		 */
557 		goto response_done;
558 	}
559 
560 	kvp_msg = (struct hv_kvp_msg *)
561 			&recv_buffer[sizeof(struct vmbuspipe_hdr) +
562 			sizeof(struct icmsg_hdr)];
563 
564 	switch (kvp_transaction.kvp_msg->kvp_hdr.operation) {
565 	case KVP_OP_GET_IP_INFO:
566 		ret = process_ob_ipinfo(msg_to_host,
567 				 (struct hv_kvp_ip_msg *)kvp_msg,
568 				 KVP_OP_GET_IP_INFO);
569 		if (ret < 0)
570 			icmsghdrp->status = HV_E_FAIL;
571 
572 		goto response_done;
573 	case KVP_OP_SET_IP_INFO:
574 		goto response_done;
575 	case KVP_OP_GET:
576 		kvp_data = &kvp_msg->body.kvp_get.data;
577 		goto copy_value;
578 
579 	case KVP_OP_SET:
580 	case KVP_OP_DELETE:
581 		goto response_done;
582 
583 	default:
584 		break;
585 	}
586 
587 	kvp_data = &kvp_msg->body.kvp_enum_data.data;
588 	key_name = msg_to_host->body.kvp_enum_data.data.key;
589 
590 	/*
591 	 * The windows host expects the key/value pair to be encoded
592 	 * in utf16. Ensure that the key/value size reported to the host
593 	 * will be less than or equal to the MAX size (including the
594 	 * terminating character).
595 	 */
596 	keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN,
597 				(wchar_t *) kvp_data->key,
598 				(HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2) - 2);
599 	kvp_data->key_size = 2*(keylen + 1); /* utf16 encoding */
600 
601 copy_value:
602 	value = msg_to_host->body.kvp_enum_data.data.value;
603 	valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
604 				(wchar_t *) kvp_data->value,
605 				(HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2) - 2);
606 	kvp_data->value_size = 2*(valuelen + 1); /* utf16 encoding */
607 
608 	/*
609 	 * If the utf8s to utf16s conversion failed; notify host
610 	 * of the error.
611 	 */
612 	if ((keylen < 0) || (valuelen < 0))
613 		icmsghdrp->status = HV_E_FAIL;
614 
615 	kvp_data->value_type = REG_SZ; /* all our values are strings */
616 
617 response_done:
618 	icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
619 
620 	vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
621 				VM_PKT_DATA_INBAND, 0);
622 }
623 
624 /*
625  * This callback is invoked when we get a KVP message from the host.
626  * The host ensures that only one KVP transaction can be active at a time.
627  * KVP implementation in Linux needs to forward the key to a user-mde
628  * component to retrieve the corresponding value. Consequently, we cannot
629  * respond to the host in the context of this callback. Since the host
630  * guarantees that at most only one transaction can be active at a time,
631  * we stash away the transaction state in a set of global variables.
632  */
633 
hv_kvp_onchannelcallback(void * context)634 void hv_kvp_onchannelcallback(void *context)
635 {
636 	struct vmbus_channel *channel = context;
637 	u32 recvlen;
638 	u64 requestid;
639 
640 	struct hv_kvp_msg *kvp_msg;
641 
642 	struct icmsg_hdr *icmsghdrp;
643 	int kvp_srv_version;
644 	static enum {NEGO_NOT_STARTED,
645 		     NEGO_IN_PROGRESS,
646 		     NEGO_FINISHED} host_negotiatied = NEGO_NOT_STARTED;
647 
648 	if (kvp_transaction.state < HVUTIL_READY) {
649 		/*
650 		 * If userspace daemon is not connected and host is asking
651 		 * us to negotiate we need to delay to not lose messages.
652 		 * This is important for Failover IP setting.
653 		 */
654 		if (host_negotiatied == NEGO_NOT_STARTED) {
655 			host_negotiatied = NEGO_IN_PROGRESS;
656 			schedule_delayed_work(&kvp_host_handshake_work,
657 				      HV_UTIL_NEGO_TIMEOUT * HZ);
658 		}
659 		return;
660 	}
661 	if (kvp_transaction.state > HVUTIL_READY)
662 		return;
663 
664 	vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 4, &recvlen,
665 			 &requestid);
666 
667 	if (recvlen > 0) {
668 		icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
669 			sizeof(struct vmbuspipe_hdr)];
670 
671 		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
672 			if (vmbus_prep_negotiate_resp(icmsghdrp,
673 				 recv_buffer, fw_versions, FW_VER_COUNT,
674 				 kvp_versions, KVP_VER_COUNT,
675 				 NULL, &kvp_srv_version)) {
676 				pr_info("KVP IC version %d.%d\n",
677 					kvp_srv_version >> 16,
678 					kvp_srv_version & 0xFFFF);
679 			}
680 		} else {
681 			kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
682 				sizeof(struct vmbuspipe_hdr) +
683 				sizeof(struct icmsg_hdr)];
684 
685 			/*
686 			 * Stash away this global state for completing the
687 			 * transaction; note transactions are serialized.
688 			 */
689 
690 			kvp_transaction.recv_len = recvlen;
691 			kvp_transaction.recv_req_id = requestid;
692 			kvp_transaction.kvp_msg = kvp_msg;
693 
694 			if (kvp_transaction.state < HVUTIL_READY) {
695 				/* Userspace is not registered yet */
696 				kvp_respond_to_host(NULL, HV_E_FAIL);
697 				return;
698 			}
699 			kvp_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
700 
701 			/*
702 			 * Get the information from the
703 			 * user-mode component.
704 			 * component. This transaction will be
705 			 * completed when we get the value from
706 			 * the user-mode component.
707 			 * Set a timeout to deal with
708 			 * user-mode not responding.
709 			 */
710 			schedule_work(&kvp_sendkey_work);
711 			schedule_delayed_work(&kvp_timeout_work,
712 					      HV_UTIL_TIMEOUT * HZ);
713 
714 			return;
715 
716 		}
717 
718 		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
719 			| ICMSGHDRFLAG_RESPONSE;
720 
721 		vmbus_sendpacket(channel, recv_buffer,
722 				       recvlen, requestid,
723 				       VM_PKT_DATA_INBAND, 0);
724 
725 		host_negotiatied = NEGO_FINISHED;
726 		hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
727 	}
728 
729 }
730 
kvp_on_reset(void)731 static void kvp_on_reset(void)
732 {
733 	if (cancel_delayed_work_sync(&kvp_timeout_work))
734 		kvp_respond_to_host(NULL, HV_E_FAIL);
735 	kvp_transaction.state = HVUTIL_DEVICE_INIT;
736 }
737 
738 int
hv_kvp_init(struct hv_util_service * srv)739 hv_kvp_init(struct hv_util_service *srv)
740 {
741 	recv_buffer = srv->recv_buffer;
742 	kvp_transaction.recv_channel = srv->channel;
743 
744 	/*
745 	 * When this driver loads, the user level daemon that
746 	 * processes the host requests may not yet be running.
747 	 * Defer processing channel callbacks until the daemon
748 	 * has registered.
749 	 */
750 	kvp_transaction.state = HVUTIL_DEVICE_INIT;
751 
752 	hvt = hvutil_transport_init(kvp_devname, CN_KVP_IDX, CN_KVP_VAL,
753 				    kvp_on_msg, kvp_on_reset);
754 	if (!hvt)
755 		return -EFAULT;
756 
757 	return 0;
758 }
759 
hv_kvp_deinit(void)760 void hv_kvp_deinit(void)
761 {
762 	kvp_transaction.state = HVUTIL_DEVICE_DYING;
763 	cancel_delayed_work_sync(&kvp_host_handshake_work);
764 	cancel_delayed_work_sync(&kvp_timeout_work);
765 	cancel_work_sync(&kvp_sendkey_work);
766 	hvutil_transport_destroy(hvt);
767 }
768