diff options
Diffstat (limited to 'drivers/hv/hv_kvp.c')
-rw-r--r-- | drivers/hv/hv_kvp.c | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c new file mode 100644 index 00000000000..89f52440fcf --- /dev/null +++ b/drivers/hv/hv_kvp.c @@ -0,0 +1,339 @@ +/* + * 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); +} |