1 /* 2 * linux/fs/lockd/mon.c 3 * 4 * The kernel statd client. 5 * 6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> 7 */ 8 9 #include <linux/types.h> 10 #include <linux/utsname.h> 11 #include <linux/kernel.h> 12 #include <linux/ktime.h> 13 #include <linux/slab.h> 14 15 #include <linux/sunrpc/clnt.h> 16 #include <linux/sunrpc/xprtsock.h> 17 #include <linux/sunrpc/svc.h> 18 #include <linux/lockd/lockd.h> 19 20 #include <asm/unaligned.h> 21 22 #define NLMDBG_FACILITY NLMDBG_MONITOR 23 #define NSM_PROGRAM 100024 24 #define NSM_VERSION 1 25 26 enum { 27 NSMPROC_NULL, 28 NSMPROC_STAT, 29 NSMPROC_MON, 30 NSMPROC_UNMON, 31 NSMPROC_UNMON_ALL, 32 NSMPROC_SIMU_CRASH, 33 NSMPROC_NOTIFY, 34 }; 35 36 struct nsm_args { 37 struct nsm_private *priv; 38 u32 prog; /* RPC callback info */ 39 u32 vers; 40 u32 proc; 41 42 char *mon_name; 43 }; 44 45 struct nsm_res { 46 u32 status; 47 u32 state; 48 }; 49 50 static struct rpc_program nsm_program; 51 static LIST_HEAD(nsm_handles); 52 static DEFINE_SPINLOCK(nsm_lock); 53 54 /* 55 * Local NSM state 56 */ 57 u32 __read_mostly nsm_local_state; 58 bool __read_mostly nsm_use_hostnames; 59 60 static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm) 61 { 62 return (struct sockaddr *)&nsm->sm_addr; 63 } 64 65 static struct rpc_clnt *nsm_create(void) 66 { 67 struct sockaddr_in sin = { 68 .sin_family = AF_INET, 69 .sin_addr.s_addr = htonl(INADDR_LOOPBACK), 70 }; 71 struct rpc_create_args args = { 72 .net = &init_net, 73 .protocol = XPRT_TRANSPORT_UDP, 74 .address = (struct sockaddr *)&sin, 75 .addrsize = sizeof(sin), 76 .servername = "rpc.statd", 77 .program = &nsm_program, 78 .version = NSM_VERSION, 79 .authflavor = RPC_AUTH_NULL, 80 .flags = RPC_CLNT_CREATE_NOPING, 81 }; 82 83 return rpc_create(&args); 84 } 85 86 static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res) 87 { 88 struct rpc_clnt *clnt; 89 int status; 90 struct nsm_args args = { 91 .priv = &nsm->sm_priv, 92 .prog = NLM_PROGRAM, 93 .vers = 3, 94 .proc = NLMPROC_NSM_NOTIFY, 95 .mon_name = nsm->sm_mon_name, 96 }; 97 struct rpc_message msg = { 98 .rpc_argp = &args, 99 .rpc_resp = res, 100 }; 101 102 clnt = nsm_create(); 103 if (IS_ERR(clnt)) { 104 status = PTR_ERR(clnt); 105 dprintk("lockd: failed to create NSM upcall transport, " 106 "status=%d\n", status); 107 goto out; 108 } 109 110 memset(res, 0, sizeof(*res)); 111 112 msg.rpc_proc = &clnt->cl_procinfo[proc]; 113 status = rpc_call_sync(clnt, &msg, 0); 114 if (status < 0) 115 dprintk("lockd: NSM upcall RPC failed, status=%d\n", 116 status); 117 else 118 status = 0; 119 rpc_shutdown_client(clnt); 120 out: 121 return status; 122 } 123 124 /** 125 * nsm_monitor - Notify a peer in case we reboot 126 * @host: pointer to nlm_host of peer to notify 127 * 128 * If this peer is not already monitored, this function sends an 129 * upcall to the local rpc.statd to record the name/address of 130 * the peer to notify in case we reboot. 131 * 132 * Returns zero if the peer is monitored by the local rpc.statd; 133 * otherwise a negative errno value is returned. 134 */ 135 int nsm_monitor(const struct nlm_host *host) 136 { 137 struct nsm_handle *nsm = host->h_nsmhandle; 138 struct nsm_res res; 139 int status; 140 141 dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name); 142 143 if (nsm->sm_monitored) 144 return 0; 145 146 /* 147 * Choose whether to record the caller_name or IP address of 148 * this peer in the local rpc.statd's database. 149 */ 150 nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf; 151 152 status = nsm_mon_unmon(nsm, NSMPROC_MON, &res); 153 if (unlikely(res.status != 0)) 154 status = -EIO; 155 if (unlikely(status < 0)) { 156 printk(KERN_NOTICE "lockd: cannot monitor %s\n", nsm->sm_name); 157 return status; 158 } 159 160 nsm->sm_monitored = 1; 161 if (unlikely(nsm_local_state != res.state)) { 162 nsm_local_state = res.state; 163 dprintk("lockd: NSM state changed to %d\n", nsm_local_state); 164 } 165 return 0; 166 } 167 168 /** 169 * nsm_unmonitor - Unregister peer notification 170 * @host: pointer to nlm_host of peer to stop monitoring 171 * 172 * If this peer is monitored, this function sends an upcall to 173 * tell the local rpc.statd not to send this peer a notification 174 * when we reboot. 175 */ 176 void nsm_unmonitor(const struct nlm_host *host) 177 { 178 struct nsm_handle *nsm = host->h_nsmhandle; 179 struct nsm_res res; 180 int status; 181 182 if (atomic_read(&nsm->sm_count) == 1 183 && nsm->sm_monitored && !nsm->sm_sticky) { 184 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name); 185 186 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res); 187 if (res.status != 0) 188 status = -EIO; 189 if (status < 0) 190 printk(KERN_NOTICE "lockd: cannot unmonitor %s\n", 191 nsm->sm_name); 192 else 193 nsm->sm_monitored = 0; 194 } 195 } 196 197 static struct nsm_handle *nsm_lookup_hostname(const char *hostname, 198 const size_t len) 199 { 200 struct nsm_handle *nsm; 201 202 list_for_each_entry(nsm, &nsm_handles, sm_link) 203 if (strlen(nsm->sm_name) == len && 204 memcmp(nsm->sm_name, hostname, len) == 0) 205 return nsm; 206 return NULL; 207 } 208 209 static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap) 210 { 211 struct nsm_handle *nsm; 212 213 list_for_each_entry(nsm, &nsm_handles, sm_link) 214 if (rpc_cmp_addr(nsm_addr(nsm), sap)) 215 return nsm; 216 return NULL; 217 } 218 219 static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv) 220 { 221 struct nsm_handle *nsm; 222 223 list_for_each_entry(nsm, &nsm_handles, sm_link) 224 if (memcmp(nsm->sm_priv.data, priv->data, 225 sizeof(priv->data)) == 0) 226 return nsm; 227 return NULL; 228 } 229 230 /* 231 * Construct a unique cookie to match this nsm_handle to this monitored 232 * host. It is passed to the local rpc.statd via NSMPROC_MON, and 233 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these 234 * requests. 235 * 236 * The NSM protocol requires that these cookies be unique while the 237 * system is running. We prefer a stronger requirement of making them 238 * unique across reboots. If user space bugs cause a stale cookie to 239 * be sent to the kernel, it could cause the wrong host to lose its 240 * lock state if cookies were not unique across reboots. 241 * 242 * The cookies are exposed only to local user space via loopback. They 243 * do not appear on the physical network. If we want greater security 244 * for some reason, nsm_init_private() could perform a one-way hash to 245 * obscure the contents of the cookie. 246 */ 247 static void nsm_init_private(struct nsm_handle *nsm) 248 { 249 u64 *p = (u64 *)&nsm->sm_priv.data; 250 struct timespec ts; 251 s64 ns; 252 253 ktime_get_ts(&ts); 254 ns = timespec_to_ns(&ts); 255 put_unaligned(ns, p); 256 put_unaligned((unsigned long)nsm, p + 1); 257 } 258 259 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 260 const size_t salen, 261 const char *hostname, 262 const size_t hostname_len) 263 { 264 struct nsm_handle *new; 265 266 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL); 267 if (unlikely(new == NULL)) 268 return NULL; 269 270 atomic_set(&new->sm_count, 1); 271 new->sm_name = (char *)(new + 1); 272 memcpy(nsm_addr(new), sap, salen); 273 new->sm_addrlen = salen; 274 nsm_init_private(new); 275 276 if (rpc_ntop(nsm_addr(new), new->sm_addrbuf, 277 sizeof(new->sm_addrbuf)) == 0) 278 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf), 279 "unsupported address family"); 280 memcpy(new->sm_name, hostname, hostname_len); 281 new->sm_name[hostname_len] = '\0'; 282 283 return new; 284 } 285 286 /** 287 * nsm_get_handle - Find or create a cached nsm_handle 288 * @sap: pointer to socket address of handle to find 289 * @salen: length of socket address 290 * @hostname: pointer to C string containing hostname to find 291 * @hostname_len: length of C string 292 * 293 * Behavior is modulated by the global nsm_use_hostnames variable. 294 * 295 * Returns a cached nsm_handle after bumping its ref count, or 296 * returns a fresh nsm_handle if a handle that matches @sap and/or 297 * @hostname cannot be found in the handle cache. Returns NULL if 298 * an error occurs. 299 */ 300 struct nsm_handle *nsm_get_handle(const struct sockaddr *sap, 301 const size_t salen, const char *hostname, 302 const size_t hostname_len) 303 { 304 struct nsm_handle *cached, *new = NULL; 305 306 if (hostname && memchr(hostname, '/', hostname_len) != NULL) { 307 if (printk_ratelimit()) { 308 printk(KERN_WARNING "Invalid hostname \"%.*s\" " 309 "in NFS lock request\n", 310 (int)hostname_len, hostname); 311 } 312 return NULL; 313 } 314 315 retry: 316 spin_lock(&nsm_lock); 317 318 if (nsm_use_hostnames && hostname != NULL) 319 cached = nsm_lookup_hostname(hostname, hostname_len); 320 else 321 cached = nsm_lookup_addr(sap); 322 323 if (cached != NULL) { 324 atomic_inc(&cached->sm_count); 325 spin_unlock(&nsm_lock); 326 kfree(new); 327 dprintk("lockd: found nsm_handle for %s (%s), " 328 "cnt %d\n", cached->sm_name, 329 cached->sm_addrbuf, 330 atomic_read(&cached->sm_count)); 331 return cached; 332 } 333 334 if (new != NULL) { 335 list_add(&new->sm_link, &nsm_handles); 336 spin_unlock(&nsm_lock); 337 dprintk("lockd: created nsm_handle for %s (%s)\n", 338 new->sm_name, new->sm_addrbuf); 339 return new; 340 } 341 342 spin_unlock(&nsm_lock); 343 344 new = nsm_create_handle(sap, salen, hostname, hostname_len); 345 if (unlikely(new == NULL)) 346 return NULL; 347 goto retry; 348 } 349 350 /** 351 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle 352 * @info: pointer to NLMPROC_SM_NOTIFY arguments 353 * 354 * Returns a matching nsm_handle if found in the nsm cache. The returned 355 * nsm_handle's reference count is bumped. Otherwise returns NULL if some 356 * error occurred. 357 */ 358 struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info) 359 { 360 struct nsm_handle *cached; 361 362 spin_lock(&nsm_lock); 363 364 cached = nsm_lookup_priv(&info->priv); 365 if (unlikely(cached == NULL)) { 366 spin_unlock(&nsm_lock); 367 dprintk("lockd: never saw rebooted peer '%.*s' before\n", 368 info->len, info->mon); 369 return cached; 370 } 371 372 atomic_inc(&cached->sm_count); 373 spin_unlock(&nsm_lock); 374 375 dprintk("lockd: host %s (%s) rebooted, cnt %d\n", 376 cached->sm_name, cached->sm_addrbuf, 377 atomic_read(&cached->sm_count)); 378 return cached; 379 } 380 381 /** 382 * nsm_release - Release an NSM handle 383 * @nsm: pointer to handle to be released 384 * 385 */ 386 void nsm_release(struct nsm_handle *nsm) 387 { 388 if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) { 389 list_del(&nsm->sm_link); 390 spin_unlock(&nsm_lock); 391 dprintk("lockd: destroyed nsm_handle for %s (%s)\n", 392 nsm->sm_name, nsm->sm_addrbuf); 393 kfree(nsm); 394 } 395 } 396 397 /* 398 * XDR functions for NSM. 399 * 400 * See http://www.opengroup.org/ for details on the Network 401 * Status Monitor wire protocol. 402 */ 403 404 static void encode_nsm_string(struct xdr_stream *xdr, const char *string) 405 { 406 const u32 len = strlen(string); 407 __be32 *p; 408 409 BUG_ON(len > SM_MAXSTRLEN); 410 p = xdr_reserve_space(xdr, 4 + len); 411 xdr_encode_opaque(p, string, len); 412 } 413 414 /* 415 * "mon_name" specifies the host to be monitored. 416 */ 417 static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp) 418 { 419 encode_nsm_string(xdr, argp->mon_name); 420 } 421 422 /* 423 * The "my_id" argument specifies the hostname and RPC procedure 424 * to be called when the status manager receives notification 425 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" 426 * has changed. 427 */ 428 static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp) 429 { 430 __be32 *p; 431 432 encode_nsm_string(xdr, utsname()->nodename); 433 p = xdr_reserve_space(xdr, 4 + 4 + 4); 434 *p++ = cpu_to_be32(argp->prog); 435 *p++ = cpu_to_be32(argp->vers); 436 *p = cpu_to_be32(argp->proc); 437 } 438 439 /* 440 * The "mon_id" argument specifies the non-private arguments 441 * of an NSMPROC_MON or NSMPROC_UNMON call. 442 */ 443 static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp) 444 { 445 encode_mon_name(xdr, argp); 446 encode_my_id(xdr, argp); 447 } 448 449 /* 450 * The "priv" argument may contain private information required 451 * by the NSMPROC_MON call. This information will be supplied in the 452 * NLMPROC_SM_NOTIFY call. 453 */ 454 static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp) 455 { 456 __be32 *p; 457 458 p = xdr_reserve_space(xdr, SM_PRIV_SIZE); 459 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE); 460 } 461 462 static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr, 463 const struct nsm_args *argp) 464 { 465 encode_mon_id(xdr, argp); 466 encode_priv(xdr, argp); 467 } 468 469 static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr, 470 const struct nsm_args *argp) 471 { 472 encode_mon_id(xdr, argp); 473 } 474 475 static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp, 476 struct xdr_stream *xdr, 477 struct nsm_res *resp) 478 { 479 __be32 *p; 480 481 p = xdr_inline_decode(xdr, 4 + 4); 482 if (unlikely(p == NULL)) 483 return -EIO; 484 resp->status = be32_to_cpup(p++); 485 resp->state = be32_to_cpup(p); 486 487 dprintk("lockd: %s status %d state %d\n", 488 __func__, resp->status, resp->state); 489 return 0; 490 } 491 492 static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp, 493 struct xdr_stream *xdr, 494 struct nsm_res *resp) 495 { 496 __be32 *p; 497 498 p = xdr_inline_decode(xdr, 4); 499 if (unlikely(p == NULL)) 500 return -EIO; 501 resp->state = be32_to_cpup(p); 502 503 dprintk("lockd: %s state %d\n", __func__, resp->state); 504 return 0; 505 } 506 507 #define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 508 #define SM_my_id_sz (SM_my_name_sz+3) 509 #define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 510 #define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz) 511 #define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE)) 512 #define SM_mon_sz (SM_mon_id_sz+SM_priv_sz) 513 #define SM_monres_sz 2 514 #define SM_unmonres_sz 1 515 516 static struct rpc_procinfo nsm_procedures[] = { 517 [NSMPROC_MON] = { 518 .p_proc = NSMPROC_MON, 519 .p_encode = (kxdreproc_t)nsm_xdr_enc_mon, 520 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat_res, 521 .p_arglen = SM_mon_sz, 522 .p_replen = SM_monres_sz, 523 .p_statidx = NSMPROC_MON, 524 .p_name = "MONITOR", 525 }, 526 [NSMPROC_UNMON] = { 527 .p_proc = NSMPROC_UNMON, 528 .p_encode = (kxdreproc_t)nsm_xdr_enc_unmon, 529 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat, 530 .p_arglen = SM_mon_id_sz, 531 .p_replen = SM_unmonres_sz, 532 .p_statidx = NSMPROC_UNMON, 533 .p_name = "UNMONITOR", 534 }, 535 }; 536 537 static struct rpc_version nsm_version1 = { 538 .number = 1, 539 .nrprocs = ARRAY_SIZE(nsm_procedures), 540 .procs = nsm_procedures 541 }; 542 543 static struct rpc_version * nsm_version[] = { 544 [1] = &nsm_version1, 545 }; 546 547 static struct rpc_stat nsm_stats; 548 549 static struct rpc_program nsm_program = { 550 .name = "statd", 551 .number = NSM_PROGRAM, 552 .nrvers = ARRAY_SIZE(nsm_version), 553 .version = nsm_version, 554 .stats = &nsm_stats 555 }; 556