/*
* 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) {
vmbus_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);
}
