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 32 33 /* 34 * Global state maintained for transaction that is being processed. 35 * Note that only one transaction can be active at any point in time. 36 * 37 * This state is set when we receive a request from the host; we 38 * cleanup this state when the transaction is completed - when we respond 39 * to the host with the key value. 40 */ 41 42 static struct { 43 bool active; /* transaction status - active or not */ 44 int recv_len; /* number of bytes received. */ 45 struct hv_kvp_msg *kvp_msg; /* current message */ 46 struct vmbus_channel *recv_channel; /* chn we got the request */ 47 u64 recv_req_id; /* request ID. */ 48 void *kvp_context; /* for the channel callback */ 49 } kvp_transaction; 50 51 static void kvp_send_key(struct work_struct *dummy); 52 53 #define TIMEOUT_FIRED 1 54 55 static void kvp_respond_to_host(char *key, char *value, int error); 56 static void kvp_work_func(struct work_struct *dummy); 57 static void kvp_register(void); 58 59 static DECLARE_DELAYED_WORK(kvp_work, kvp_work_func); 60 static DECLARE_WORK(kvp_sendkey_work, kvp_send_key); 61 62 static struct cb_id kvp_id = { CN_KVP_IDX, CN_KVP_VAL }; 63 static const char kvp_name[] = "kvp_kernel_module"; 64 static u8 *recv_buffer; 65 /* 66 * Register the kernel component with the user-level daemon. 67 * As part of this registration, pass the LIC version number. 68 */ 69 70 static void 71 kvp_register(void) 72 { 73 74 struct cn_msg *msg; 75 struct hv_kvp_msg *kvp_msg; 76 char *version; 77 78 msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg), GFP_ATOMIC); 79 80 if (msg) { 81 kvp_msg = (struct hv_kvp_msg *)msg->data; 82 version = kvp_msg->body.kvp_register.version; 83 msg->id.idx = CN_KVP_IDX; 84 msg->id.val = CN_KVP_VAL; 85 86 kvp_msg->kvp_hdr.operation = KVP_OP_REGISTER; 87 strcpy(version, HV_DRV_VERSION); 88 msg->len = sizeof(struct hv_kvp_msg); 89 cn_netlink_send(msg, 0, GFP_ATOMIC); 90 kfree(msg); 91 } 92 } 93 static void 94 kvp_work_func(struct work_struct *dummy) 95 { 96 /* 97 * If the timer fires, the user-mode component has not responded; 98 * process the pending transaction. 99 */ 100 kvp_respond_to_host("Unknown key", "Guest timed out", TIMEOUT_FIRED); 101 } 102 103 /* 104 * Callback when data is received from user mode. 105 */ 106 107 static void 108 kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp) 109 { 110 struct hv_kvp_msg *message; 111 struct hv_kvp_msg_enumerate *data; 112 113 message = (struct hv_kvp_msg *)msg->data; 114 switch (message->kvp_hdr.operation) { 115 case KVP_OP_REGISTER: 116 pr_info("KVP: user-mode registering done.\n"); 117 kvp_register(); 118 kvp_transaction.active = false; 119 hv_kvp_onchannelcallback(kvp_transaction.kvp_context); 120 break; 121 122 default: 123 data = &message->body.kvp_enum_data; 124 /* 125 * Complete the transaction by forwarding the key value 126 * to the host. But first, cancel the timeout. 127 */ 128 if (cancel_delayed_work_sync(&kvp_work)) 129 kvp_respond_to_host(data->data.key, 130 data->data.value, 131 !strlen(data->data.key)); 132 } 133 } 134 135 static void 136 kvp_send_key(struct work_struct *dummy) 137 { 138 struct cn_msg *msg; 139 struct hv_kvp_msg *message; 140 struct hv_kvp_msg *in_msg; 141 __u8 operation = kvp_transaction.kvp_msg->kvp_hdr.operation; 142 __u8 pool = kvp_transaction.kvp_msg->kvp_hdr.pool; 143 __u32 val32; 144 __u64 val64; 145 146 msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg) , GFP_ATOMIC); 147 if (!msg) 148 return; 149 150 msg->id.idx = CN_KVP_IDX; 151 msg->id.val = CN_KVP_VAL; 152 153 message = (struct hv_kvp_msg *)msg->data; 154 message->kvp_hdr.operation = operation; 155 message->kvp_hdr.pool = pool; 156 in_msg = kvp_transaction.kvp_msg; 157 158 /* 159 * The key/value strings sent from the host are encoded in 160 * in utf16; convert it to utf8 strings. 161 * The host assures us that the utf16 strings will not exceed 162 * the max lengths specified. We will however, reserve room 163 * for the string terminating character - in the utf16s_utf8s() 164 * function we limit the size of the buffer where the converted 165 * string is placed to HV_KVP_EXCHANGE_MAX_*_SIZE -1 to gaurantee 166 * that the strings can be properly terminated! 167 */ 168 169 switch (message->kvp_hdr.operation) { 170 case KVP_OP_SET: 171 switch (in_msg->body.kvp_set.data.value_type) { 172 case REG_SZ: 173 /* 174 * The value is a string - utf16 encoding. 175 */ 176 message->body.kvp_set.data.value_size = 177 utf16s_to_utf8s( 178 (wchar_t *)in_msg->body.kvp_set.data.value, 179 in_msg->body.kvp_set.data.value_size, 180 UTF16_LITTLE_ENDIAN, 181 message->body.kvp_set.data.value, 182 HV_KVP_EXCHANGE_MAX_VALUE_SIZE - 1) + 1; 183 break; 184 185 case REG_U32: 186 /* 187 * The value is a 32 bit scalar. 188 * We save this as a utf8 string. 189 */ 190 val32 = in_msg->body.kvp_set.data.value_u32; 191 message->body.kvp_set.data.value_size = 192 sprintf(message->body.kvp_set.data.value, 193 "%d", val32) + 1; 194 break; 195 196 case REG_U64: 197 /* 198 * The value is a 64 bit scalar. 199 * We save this as a utf8 string. 200 */ 201 val64 = in_msg->body.kvp_set.data.value_u64; 202 message->body.kvp_set.data.value_size = 203 sprintf(message->body.kvp_set.data.value, 204 "%llu", val64) + 1; 205 break; 206 207 } 208 case KVP_OP_GET: 209 message->body.kvp_set.data.key_size = 210 utf16s_to_utf8s( 211 (wchar_t *)in_msg->body.kvp_set.data.key, 212 in_msg->body.kvp_set.data.key_size, 213 UTF16_LITTLE_ENDIAN, 214 message->body.kvp_set.data.key, 215 HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1; 216 break; 217 218 case KVP_OP_DELETE: 219 message->body.kvp_delete.key_size = 220 utf16s_to_utf8s( 221 (wchar_t *)in_msg->body.kvp_delete.key, 222 in_msg->body.kvp_delete.key_size, 223 UTF16_LITTLE_ENDIAN, 224 message->body.kvp_delete.key, 225 HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1; 226 break; 227 228 case KVP_OP_ENUMERATE: 229 message->body.kvp_enum_data.index = 230 in_msg->body.kvp_enum_data.index; 231 break; 232 } 233 234 msg->len = sizeof(struct hv_kvp_msg); 235 cn_netlink_send(msg, 0, GFP_ATOMIC); 236 kfree(msg); 237 238 return; 239 } 240 241 /* 242 * Send a response back to the host. 243 */ 244 245 static void 246 kvp_respond_to_host(char *key, char *value, int error) 247 { 248 struct hv_kvp_msg *kvp_msg; 249 struct hv_kvp_exchg_msg_value *kvp_data; 250 char *key_name; 251 struct icmsg_hdr *icmsghdrp; 252 int keylen = 0; 253 int valuelen = 0; 254 u32 buf_len; 255 struct vmbus_channel *channel; 256 u64 req_id; 257 258 /* 259 * If a transaction is not active; log and return. 260 */ 261 262 if (!kvp_transaction.active) { 263 /* 264 * This is a spurious call! 265 */ 266 pr_warn("KVP: Transaction not active\n"); 267 return; 268 } 269 /* 270 * Copy the global state for completing the transaction. Note that 271 * only one transaction can be active at a time. 272 */ 273 274 buf_len = kvp_transaction.recv_len; 275 channel = kvp_transaction.recv_channel; 276 req_id = kvp_transaction.recv_req_id; 277 278 kvp_transaction.active = false; 279 280 icmsghdrp = (struct icmsg_hdr *) 281 &recv_buffer[sizeof(struct vmbuspipe_hdr)]; 282 283 if (channel->onchannel_callback == NULL) 284 /* 285 * We have raced with util driver being unloaded; 286 * silently return. 287 */ 288 return; 289 290 291 /* 292 * If the error parameter is set, terminate the host's enumeration 293 * on this pool. 294 */ 295 if (error) { 296 /* 297 * Something failed or the we have timedout; 298 * terminate the current host-side iteration. 299 */ 300 icmsghdrp->status = HV_S_CONT; 301 goto response_done; 302 } 303 304 icmsghdrp->status = HV_S_OK; 305 306 kvp_msg = (struct hv_kvp_msg *) 307 &recv_buffer[sizeof(struct vmbuspipe_hdr) + 308 sizeof(struct icmsg_hdr)]; 309 310 switch (kvp_transaction.kvp_msg->kvp_hdr.operation) { 311 case KVP_OP_GET: 312 kvp_data = &kvp_msg->body.kvp_get.data; 313 goto copy_value; 314 315 case KVP_OP_SET: 316 case KVP_OP_DELETE: 317 goto response_done; 318 319 default: 320 break; 321 } 322 323 kvp_data = &kvp_msg->body.kvp_enum_data.data; 324 key_name = key; 325 326 /* 327 * The windows host expects the key/value pair to be encoded 328 * in utf16. Ensure that the key/value size reported to the host 329 * will be less than or equal to the MAX size (including the 330 * terminating character). 331 */ 332 keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN, 333 (wchar_t *) kvp_data->key, 334 (HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2) - 2); 335 kvp_data->key_size = 2*(keylen + 1); /* utf16 encoding */ 336 337 copy_value: 338 valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN, 339 (wchar_t *) kvp_data->value, 340 (HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2) - 2); 341 kvp_data->value_size = 2*(valuelen + 1); /* utf16 encoding */ 342 343 /* 344 * If the utf8s to utf16s conversion failed; notify host 345 * of the error. 346 */ 347 if ((keylen < 0) || (valuelen < 0)) 348 icmsghdrp->status = HV_E_FAIL; 349 350 kvp_data->value_type = REG_SZ; /* all our values are strings */ 351 352 response_done: 353 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; 354 355 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id, 356 VM_PKT_DATA_INBAND, 0); 357 358 } 359 360 /* 361 * This callback is invoked when we get a KVP message from the host. 362 * The host ensures that only one KVP transaction can be active at a time. 363 * KVP implementation in Linux needs to forward the key to a user-mde 364 * component to retrive the corresponding value. Consequently, we cannot 365 * respond to the host in the conext of this callback. Since the host 366 * guarantees that at most only one transaction can be active at a time, 367 * we stash away the transaction state in a set of global variables. 368 */ 369 370 void hv_kvp_onchannelcallback(void *context) 371 { 372 struct vmbus_channel *channel = context; 373 u32 recvlen; 374 u64 requestid; 375 376 struct hv_kvp_msg *kvp_msg; 377 378 struct icmsg_hdr *icmsghdrp; 379 struct icmsg_negotiate *negop = NULL; 380 381 if (kvp_transaction.active) { 382 /* 383 * We will defer processing this callback once 384 * the current transaction is complete. 385 */ 386 kvp_transaction.kvp_context = context; 387 return; 388 } 389 390 vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE, &recvlen, &requestid); 391 392 if (recvlen > 0) { 393 icmsghdrp = (struct icmsg_hdr *)&recv_buffer[ 394 sizeof(struct vmbuspipe_hdr)]; 395 396 if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) { 397 vmbus_prep_negotiate_resp(icmsghdrp, negop, 398 recv_buffer, MAX_SRV_VER, MAX_SRV_VER); 399 } else { 400 kvp_msg = (struct hv_kvp_msg *)&recv_buffer[ 401 sizeof(struct vmbuspipe_hdr) + 402 sizeof(struct icmsg_hdr)]; 403 404 /* 405 * Stash away this global state for completing the 406 * transaction; note transactions are serialized. 407 */ 408 409 kvp_transaction.recv_len = recvlen; 410 kvp_transaction.recv_channel = channel; 411 kvp_transaction.recv_req_id = requestid; 412 kvp_transaction.active = true; 413 kvp_transaction.kvp_msg = kvp_msg; 414 415 /* 416 * Get the information from the 417 * user-mode component. 418 * component. This transaction will be 419 * completed when we get the value from 420 * the user-mode component. 421 * Set a timeout to deal with 422 * user-mode not responding. 423 */ 424 schedule_work(&kvp_sendkey_work); 425 schedule_delayed_work(&kvp_work, 5*HZ); 426 427 return; 428 429 } 430 431 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION 432 | ICMSGHDRFLAG_RESPONSE; 433 434 vmbus_sendpacket(channel, recv_buffer, 435 recvlen, requestid, 436 VM_PKT_DATA_INBAND, 0); 437 } 438 439 } 440 441 int 442 hv_kvp_init(struct hv_util_service *srv) 443 { 444 int err; 445 446 err = cn_add_callback(&kvp_id, kvp_name, kvp_cn_callback); 447 if (err) 448 return err; 449 recv_buffer = srv->recv_buffer; 450 451 /* 452 * When this driver loads, the user level daemon that 453 * processes the host requests may not yet be running. 454 * Defer processing channel callbacks until the daemon 455 * has registered. 456 */ 457 kvp_transaction.active = true; 458 459 return 0; 460 } 461 462 void hv_kvp_deinit(void) 463 { 464 cn_del_callback(&kvp_id); 465 cancel_delayed_work_sync(&kvp_work); 466 cancel_work_sync(&kvp_sendkey_work); 467 } 468