drivers/hv/hv_kvp.c - linux - Git at Google

 /*
  * 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>

 #include "hv_kvp.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. */
 	int index; /* current index */
 	struct vmbus_channel *recv_channel; /* chn we got the request */
 	u64 recv_req_id; /* request ID. */
 } 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;

 	msg = kzalloc(sizeof(*msg) + strlen(HV_DRV_VERSION) + 1 , GFP_ATOMIC);

 	if (msg) {
 		msg->id.idx =  CN_KVP_IDX;
 		msg->id.val = CN_KVP_VAL;
 		msg->seq = KVP_REGISTER;
 		strcpy(msg->data, HV_DRV_VERSION);
 		msg->len = strlen(HV_DRV_VERSION) + 1;
 		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_ku_msg *message;

 	message = (struct hv_ku_msg *)msg->data;
 	if (msg->seq == KVP_REGISTER) {
 		pr_info("KVP: user-mode registering done.\n");
 		kvp_register();
 	}

 	if (msg->seq == KVP_USER_SET) {
 		/*
 		 * 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(message->kvp_key,
 						message->kvp_value,
 						!strlen(message->kvp_key));
 	}
 }

 static void
 kvp_send_key(struct work_struct *dummy)
 {
 	struct cn_msg *msg;
 	int index = kvp_transaction.index;

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

 	if (msg) {
 		msg->id.idx =  CN_KVP_IDX;
 		msg->id.val = CN_KVP_VAL;
 		msg->seq = KVP_KERNEL_GET;
 		((struct hv_ku_msg *)msg->data)->kvp_index = index;
 		msg->len = sizeof(struct hv_ku_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_msg_enumerate  *kvp_data;
 	char	*key_name;
 	struct icmsg_hdr *icmsghdrp;
 	int	keylen, valuelen;
 	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;

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

 	icmsghdrp = (struct icmsg_hdr *)
 			&recv_buffer[sizeof(struct vmbuspipe_hdr)];
 	kvp_msg = (struct hv_kvp_msg *)
 			&recv_buffer[sizeof(struct vmbuspipe_hdr) +
 			sizeof(struct icmsg_hdr)];
 	kvp_data = &kvp_msg->kvp_data;
 	key_name = key;

 	/*
 	 * If the error parameter is set, terminate the host's enumeration.
 	 */
 	if (error) {
 		/*
 		 * We don't support this index or the we have timedout;
 		 * terminate the host-side iteration by returning an error.
 		 */
 		icmsghdrp->status = HV_E_FAIL;
 		goto response_done;
 	}

 	/*
 	 * The windows host expects the key/value pair to be encoded
 	 * in utf16.
 	 */
 	keylen = utf8s_to_utf16s(key_name, strlen(key_name),
 				(wchar_t *)kvp_data->data.key);
 	kvp_data->data.key_size = 2*(keylen + 1); /* utf16 encoding */
 	valuelen = utf8s_to_utf16s(value, strlen(value),
 				(wchar_t *)kvp_data->data.value);
 	kvp_data->data.value_size = 2*(valuelen + 1); /* utf16 encoding */

 	kvp_data->data.value_type = REG_SZ; /* all our values are strings */
 	icmsghdrp->status = HV_S_OK;

 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 hv_kvp_msg_enumerate *kvp_data;

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


 	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) {
 			prep_negotiate_resp(icmsghdrp, negop, recv_buffer);
 		} else {
 			kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
 				sizeof(struct vmbuspipe_hdr) +
 				sizeof(struct icmsg_hdr)];

 			kvp_data = &kvp_msg->kvp_data;

 			/*
 			 * We only support the "get" operation on
 			 * "KVP_POOL_AUTO" pool.
 			 */

 			if ((kvp_msg->kvp_hdr.pool != KVP_POOL_AUTO) ||
 				(kvp_msg->kvp_hdr.operation !=
 				KVP_OP_ENUMERATE)) {
 				icmsghdrp->status = HV_E_FAIL;
 				goto callback_done;
 			}

 			/*
 			 * 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.index = kvp_data->index;

 			/*
 			 * 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;

 		}

 callback_done:

 		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;

 	return 0;
 }

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

	#include "hv_kvp.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. */
	int index; /* current index */
	struct vmbus_channel recv_channel; / chn we got the request */
	u64 recv_req_id; /* request ID. */
	} 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;

	msg = kzalloc(sizeof(*msg) + strlen(HV_DRV_VERSION) + 1 , GFP_ATOMIC);

	if (msg) {
	msg->id.idx = CN_KVP_IDX;
	msg->id.val = CN_KVP_VAL;
	msg->seq = KVP_REGISTER;
	strcpy(msg->data, HV_DRV_VERSION);
	msg->len = strlen(HV_DRV_VERSION) + 1;
	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_ku_msg *message;

	message = (struct hv_ku_msg *)msg->data;
	if (msg->seq == KVP_REGISTER) {
	pr_info("KVP: user-mode registering done.\n");
	kvp_register();
	}

	if (msg->seq == KVP_USER_SET) {
	/*
	* 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(message->kvp_key,
	message->kvp_value,
	!strlen(message->kvp_key));
	}
	}

	static void
	kvp_send_key(struct work_struct *dummy)
	{
	struct cn_msg *msg;
	int index = kvp_transaction.index;

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

	if (msg) {
	msg->id.idx = CN_KVP_IDX;
	msg->id.val = CN_KVP_VAL;
	msg->seq = KVP_KERNEL_GET;
	((struct hv_ku_msg *)msg->data)->kvp_index = index;
	msg->len = sizeof(struct hv_ku_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_msg_enumerate *kvp_data;
	char *key_name;
	struct icmsg_hdr *icmsghdrp;
	int keylen, valuelen;
	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;

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

	icmsghdrp = (struct icmsg_hdr *)
	&recv_buffer[sizeof(struct vmbuspipe_hdr)];
	kvp_msg = (struct hv_kvp_msg *)
	&recv_buffer[sizeof(struct vmbuspipe_hdr) +
	sizeof(struct icmsg_hdr)];
	kvp_data = &kvp_msg->kvp_data;
	key_name = key;

	/*
	* If the error parameter is set, terminate the host's enumeration.
	*/
	if (error) {
	/*
	* We don't support this index or the we have timedout;
	* terminate the host-side iteration by returning an error.
	*/
	icmsghdrp->status = HV_E_FAIL;
	goto response_done;
	}

	/*
	* The windows host expects the key/value pair to be encoded
	* in utf16.
	*/
	keylen = utf8s_to_utf16s(key_name, strlen(key_name),
	(wchar_t *)kvp_data->data.key);
	kvp_data->data.key_size = 2(keylen + 1); / utf16 encoding */
	valuelen = utf8s_to_utf16s(value, strlen(value),
	(wchar_t *)kvp_data->data.value);
	kvp_data->data.value_size = 2(valuelen + 1); / utf16 encoding */

	kvp_data->data.value_type = REG_SZ; /* all our values are strings */
	icmsghdrp->status = HV_S_OK;

	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 hv_kvp_msg_enumerate *kvp_data;

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


	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) {
	prep_negotiate_resp(icmsghdrp, negop, recv_buffer);
	} else {
	kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
	sizeof(struct vmbuspipe_hdr) +
	sizeof(struct icmsg_hdr)];

	kvp_data = &kvp_msg->kvp_data;

	/*
	* We only support the "get" operation on
	* "KVP_POOL_AUTO" pool.
	*/

	if ((kvp_msg->kvp_hdr.pool != KVP_POOL_AUTO) \|\|
	(kvp_msg->kvp_hdr.operation !=
	KVP_OP_ENUMERATE)) {
	icmsghdrp->status = HV_E_FAIL;
	goto callback_done;
	}

	/*
	* 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.index = kvp_data->index;

	/*
	* 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;

	}

	callback_done:

	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;

	return 0;
	}

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