[PATCH 03/17] Drivers: hv: kvp: Cleanup error handling in KVP

K. Y. Srinivasan
2012-07-24T15:49:07Z

In preparation to implementing IP injection, cleanup the way we propagate
and handle errors both in the driver as well as in the user level daemon.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
---
drivers/hv/hv_kvp.c | 112 +++++++++++++++++++++++++++++++++++++---------
include/linux/hyperv.h | 17 +++++---
tools/hv/hv_kvp_daemon.c | 70 +++++++++++++++-------------
3 files changed, 138 insertions(+), 61 deletions(-)

diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index 0012eed..9b7fc4a 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -48,13 +48,24 @@ static struct {
void *kvp_context; /* for the channel callback */
} kvp_transaction;

+/*
+ * Before we can accept KVP messages from the host, we need
+ * to handshake with the user level daemon. This state tarcks
+ * if we are in the handshake phase.
+ */
+static bool in_hand_shake = true;
+
+/*
+ * This state maintains the version number registered by the daemon.
+ */
+static int dm_reg_value;
+
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 void kvp_register(int);

static DECLARE_DELAYED_WORK(kvp_work, kvp_work_func);
static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
@@ -68,7 +79,7 @@ static u8 *recv_buffer;
*/

static void
-kvp_register(void)
+kvp_register(int reg_value)
{

struct cn_msg *msg;
@@ -83,7 +94,7 @@ kvp_register(void)
msg->id.idx = CN_KVP_IDX;
msg->id.val = CN_KVP_VAL;

- kvp_msg->kvp_hdr.operation = KVP_OP_REGISTER;
+ kvp_msg->kvp_hdr.operation = reg_value;
strcpy(version, HV_DRV_VERSION);
msg->len = sizeof(struct hv_kvp_msg);
cn_netlink_send(msg, 0, GFP_ATOMIC);
@@ -97,9 +108,43 @@ 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);
+ kvp_respond_to_host("Unknown key", "Guest timed out", HV_E_FAIL);
+}
+
+static int kvp_handle_handshake(struct hv_kvp_msg *msg)
+{
+ int ret = 1;
+
+ switch (msg->kvp_hdr.operation) {
+ case KVP_OP_REGISTER:
+ dm_reg_value = KVP_OP_REGISTER;
+ pr_info("KVP: IP injection functionality not available\n");
+ pr_info("KVP: Upgrade the KVP daemon\n");
+ break;
+ case KVP_OP_REGISTER1:
+ dm_reg_value = KVP_OP_REGISTER1;
+ break;
+ default:
+ pr_info("KVP: incompatible daemon\n");
+ pr_info("KVP: KVP version: %d, Daemon version: %d\n",
+ KVP_OP_REGISTER1, msg->kvp_hdr.operation);
+ ret = 0;
+ }
+
+ if (ret) {
+ /*
+ * We have a compatible daemon; complete the handshake.
+ */
+ pr_info("KVP: user-mode registering done.\n");
+ kvp_register(dm_reg_value);
+ kvp_transaction.active = false;
+ if (kvp_transaction.kvp_context)
+ hv_kvp_onchannelcallback(kvp_transaction.kvp_context);
+ }
+ return ret;
}

+
/*
* Callback when data is received from user mode.
*/
@@ -109,27 +154,52 @@ kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
{
struct hv_kvp_msg *message;
struct hv_kvp_msg_enumerate *data;
+ int error = 0;

message = (struct hv_kvp_msg *)msg->data;
- switch (message->kvp_hdr.operation) {
+
+ /*
+ * If we are negotiating the version information
+ * with the daemon; handle that first.
+ */
+
+ if (in_hand_shake) {
+ if (kvp_handle_handshake(message))
+ in_hand_shake = false;
+ return;
+ }
+
+ /*
+ * Based on the version of the daemon, we propagate errors from the
+ * daemon differently.
+ */
+
+ data = &message->body.kvp_enum_data;
+
+ switch (dm_reg_value) {
case KVP_OP_REGISTER:
- pr_info("KVP: user-mode registering done.\n");
- kvp_register();
- kvp_transaction.active = false;
- hv_kvp_onchannelcallback(kvp_transaction.kvp_context);
+ /*
+ * Null string is used to pass back error condition.
+ */
+ if (!strlen(data->data.key))
+ error = HV_S_CONT;
break;

- default:
- data = &message->body.kvp_enum_data;
+ case KVP_OP_REGISTER1:
/*
- * Complete the transaction by forwarding the key value
- * to the host. But first, cancel the timeout.
+ * We use the message header information from
+ * the user level daemon to transmit errors.
*/
- if (cancel_delayed_work_sync(&kvp_work))
- kvp_respond_to_host(data->data.key,
- data->data.value,
- !strlen(data->data.key));
+ error = *((int *)(&message->kvp_hdr.operation));
+ break;
}
+
+ /*
+ * 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(data->data.key, data->data.value, error);
}

static void
@@ -287,6 +357,7 @@ kvp_respond_to_host(char *key, char *value, int error)
*/
return;

+ icmsghdrp->status = error;

/*
* If the error parameter is set, terminate the host's enumeration
@@ -294,15 +365,12 @@ kvp_respond_to_host(char *key, char *value, int error)
*/
if (error) {
/*
- * Something failed or the we have timedout;
+ * Something failed or we have timedout;
* terminate the current host-side iteration.
*/
- icmsghdrp->status = HV_S_CONT;
goto response_done;
}

- icmsghdrp->status = HV_S_OK;
-
kvp_msg = (struct hv_kvp_msg *)
&recv_buffer[sizeof(struct vmbuspipe_hdr) +
sizeof(struct icmsg_hdr)];
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 3c56ca7..5552443 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -181,6 +181,17 @@ enum hv_kvp_exchg_pool {
KVP_POOL_COUNT /* Number of pools, must be last. */
};

+/*
+ * Some Hyper-V status codes.
+ */
+
+#define HV_S_OK 0x00000000
+#define HV_E_FAIL 0x80004005
+#define HV_S_CONT 0x80070103
+#define HV_ERROR_NOT_SUPPORTED 0x80070032
+#define HV_ERROR_MACHINE_LOCKED 0x800704F7
+#define HV_ERROR_DEVICE_NOT_CONNECTED 0x8007048F
+
#define ADDR_FAMILY_NONE 0x00
#define ADDR_FAMILY_IPV4 0x01
#define ADDR_FAMILY_IPV6 0x02
@@ -1045,12 +1056,6 @@ void vmbus_driver_unregister(struct hv_driver *hv_driver);
#define ICMSGHDRFLAG_REQUEST 2
#define ICMSGHDRFLAG_RESPONSE 4

-#define HV_S_OK 0x00000000
-#define HV_E_FAIL 0x80004005
-#define HV_S_CONT 0x80070103
-#define HV_ERROR_NOT_SUPPORTED 0x80070032
-#define HV_ERROR_MACHINE_LOCKED 0x800704F7
-#define HV_ERROR_DEVICE_NOT_CONNECTED 0x8007048F

/*
* While we want to handle util services as regular devices,
diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index 8fbcf7b..72f5fd3 100644
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -71,13 +71,14 @@ enum key_index {
static char kvp_send_buffer[4096];
static char kvp_recv_buffer[4096 * 2];
static struct sockaddr_nl addr;
+static int in_hand_shake = 1;

static char *os_name = "";
static char *os_major = "";
static char *os_minor = "";
static char *processor_arch;
static char *os_build;
-static char *lic_version;
+static char *lic_version = "Unknown version";
static struct utsname uts_buf;

@@ -394,7 +395,7 @@ static int kvp_get_value(int pool, __u8 *key, int key_size, __u8 *value,
return 1;
}

-static void kvp_pool_enumerate(int pool, int index, __u8 *key, int key_size,
+static int kvp_pool_enumerate(int pool, int index, __u8 *key, int key_size,
__u8 *value, int value_size)
{
struct kvp_record *record;
@@ -406,16 +407,12 @@ static void kvp_pool_enumerate(int pool, int index, __u8 *key, int key_size,
record = kvp_file_info[pool].records;

if (index >= kvp_file_info[pool].num_records) {
- /*
- * This is an invalid index; terminate enumeration;
- * - a NULL value will do the trick.
- */
- strcpy(value, "");
- return;
+ return 1;
}

memcpy(key, record[index].key, key_size);
memcpy(value, record[index].value, value_size);
+ return 0;
}

@@ -646,6 +643,8 @@ int main(void)
char *p;
char *key_value;
char *key_name;
+ int op;
+ int pool;

daemon(1, 0);
openlog("KVP", 0, LOG_USER);
@@ -687,7 +686,7 @@ int main(void)
message->id.val = CN_KVP_VAL;

hv_msg = (struct hv_kvp_msg *)message->data;
- hv_msg->kvp_hdr.operation = KVP_OP_REGISTER;
+ hv_msg->kvp_hdr.operation = KVP_OP_REGISTER1;
message->ack = 0;
message->len = sizeof(struct hv_kvp_msg);

@@ -721,12 +720,21 @@ int main(void)
incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg);
hv_msg = (struct hv_kvp_msg *)incoming_cn_msg->data;

- switch (hv_msg->kvp_hdr.operation) {
- case KVP_OP_REGISTER:
+ /*
+ * We will use the KVP header information to pass back
+ * the error from this daemon. So, first copy the state
+ * and set the error code to success.
+ */
+ op = hv_msg->kvp_hdr.operation;
+ pool = hv_msg->kvp_hdr.pool;
+ *((int *)(&hv_msg->kvp_hdr.operation)) = HV_S_OK;
+
+ if ((in_hand_shake) && (op == KVP_OP_REGISTER1)) {
/*
* Driver is registering with us; stash away the version
* information.
*/
+ in_hand_shake = 0;
p = (char *)hv_msg->body.kvp_register.version;
lic_version = malloc(strlen(p) + 1);
if (lic_version) {
@@ -737,44 +745,42 @@ int main(void)
syslog(LOG_ERR, "malloc failed");
}
continue;
+ }

- /*
- * The current protocol with the kernel component uses a
- * NULL key name to pass an error condition.
- * For the SET, GET and DELETE operations,
- * use the existing protocol to pass back error.
- */
-
+ switch (op) {
case KVP_OP_SET:
- if (kvp_key_add_or_modify(hv_msg->kvp_hdr.pool,
+ if (kvp_key_add_or_modify(pool,
hv_msg->body.kvp_set.data.key,
hv_msg->body.kvp_set.data.key_size,
hv_msg->body.kvp_set.data.value,
hv_msg->body.kvp_set.data.value_size))
- strcpy(hv_msg->body.kvp_set.data.key, "");
+ *((int *)(&hv_msg->kvp_hdr.operation)) =
+ HV_S_CONT;
break;

case KVP_OP_GET:
- if (kvp_get_value(hv_msg->kvp_hdr.pool,
+ if (kvp_get_value(pool,
hv_msg->body.kvp_set.data.key,
hv_msg->body.kvp_set.data.key_size,
hv_msg->body.kvp_set.data.value,
hv_msg->body.kvp_set.data.value_size))
- strcpy(hv_msg->body.kvp_set.data.key, "");
+ *((int *)(&hv_msg->kvp_hdr.operation)) =
+ HV_S_CONT;
break;

case KVP_OP_DELETE:
- if (kvp_key_delete(hv_msg->kvp_hdr.pool,
+ if (kvp_key_delete(pool,
hv_msg->body.kvp_delete.key,
hv_msg->body.kvp_delete.key_size))
- strcpy(hv_msg->body.kvp_delete.key, "");
+ *((int *)(&hv_msg->kvp_hdr.operation)) =
+ HV_S_CONT;
break;

default:
break;
}

- if (hv_msg->kvp_hdr.operation != KVP_OP_ENUMERATE)
+ if (op != KVP_OP_ENUMERATE)
goto kvp_done;

/*
@@ -782,13 +788,15 @@ int main(void)
* both the key and the value; if not read from the
* appropriate pool.
*/
- if (hv_msg->kvp_hdr.pool != KVP_POOL_AUTO) {
- kvp_pool_enumerate(hv_msg->kvp_hdr.pool,
+ if (pool != KVP_POOL_AUTO) {
+ if (kvp_pool_enumerate(pool,
hv_msg->body.kvp_enum_data.index,
hv_msg->body.kvp_enum_data.data.key,
HV_KVP_EXCHANGE_MAX_KEY_SIZE,
hv_msg->body.kvp_enum_data.data.value,
- HV_KVP_EXCHANGE_MAX_VALUE_SIZE);
+ HV_KVP_EXCHANGE_MAX_VALUE_SIZE))
+ *((int *)(&hv_msg->kvp_hdr.operation)) =
+ HV_S_CONT;
goto kvp_done;
}

@@ -841,11 +849,7 @@ int main(void)
strcpy(key_name, "ProcessorArchitecture");
break;
default:
- strcpy(key_value, "Unknown Key");
- /*
- * We use a null key name to terminate enumeration.
- */
- strcpy(key_name, "");
+ *((int *)(&hv_msg->kvp_hdr.operation)) = HV_S_CONT;
break;
}
/*
--
1.7.4.1