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 const 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(struct net *net) 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 = 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 struct net *net) 88 { 89 struct rpc_clnt *clnt; 90 int status; 91 struct nsm_args args = { 92 .priv = &nsm->sm_priv, 93 .prog = NLM_PROGRAM, 94 .vers = 3, 95 .proc = NLMPROC_NSM_NOTIFY, 96 .mon_name = nsm->sm_mon_name, 97 }; 98 struct rpc_message msg = { 99 .rpc_argp = &args, 100 .rpc_resp = res, 101 }; 102 103 clnt = nsm_create(net); 104 if (IS_ERR(clnt)) { 105 status = PTR_ERR(clnt); 106 dprintk("lockd: failed to create NSM upcall transport, " 107 "status=%d\n", status); 108 goto out; 109 } 110 111 memset(res, 0, sizeof(*res)); 112 113 msg.rpc_proc = &clnt->cl_procinfo[proc]; 114 status = rpc_call_sync(clnt, &msg, 0); 115 if (status < 0) 116 dprintk("lockd: NSM upcall RPC failed, status=%d\n", 117 status); 118 else 119 status = 0; 120 rpc_shutdown_client(clnt); 121 out: 122 return status; 123 } 124 125 /** 126 * nsm_monitor - Notify a peer in case we reboot 127 * @host: pointer to nlm_host of peer to notify 128 * 129 * If this peer is not already monitored, this function sends an 130 * upcall to the local rpc.statd to record the name/address of 131 * the peer to notify in case we reboot. 132 * 133 * Returns zero if the peer is monitored by the local rpc.statd; 134 * otherwise a negative errno value is returned. 135 */ 136 int nsm_monitor(const struct nlm_host *host) 137 { 138 struct nsm_handle *nsm = host->h_nsmhandle; 139 struct nsm_res res; 140 int status; 141 142 dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name); 143 144 if (nsm->sm_monitored) 145 return 0; 146 147 /* 148 * Choose whether to record the caller_name or IP address of 149 * this peer in the local rpc.statd's database. 150 */ 151 nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf; 152 153 status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, host->net); 154 if (unlikely(res.status != 0)) 155 status = -EIO; 156 if (unlikely(status < 0)) { 157 printk(KERN_NOTICE "lockd: cannot monitor %s\n", nsm->sm_name); 158 return status; 159 } 160 161 nsm->sm_monitored = 1; 162 if (unlikely(nsm_local_state != res.state)) { 163 nsm_local_state = res.state; 164 dprintk("lockd: NSM state changed to %d\n", nsm_local_state); 165 } 166 return 0; 167 } 168 169 /** 170 * nsm_unmonitor - Unregister peer notification 171 * @host: pointer to nlm_host of peer to stop monitoring 172 * 173 * If this peer is monitored, this function sends an upcall to 174 * tell the local rpc.statd not to send this peer a notification 175 * when we reboot. 176 */ 177 void nsm_unmonitor(const struct nlm_host *host) 178 { 179 struct nsm_handle *nsm = host->h_nsmhandle; 180 struct nsm_res res; 181 int status; 182 183 if (atomic_read(&nsm->sm_count) == 1 184 && nsm->sm_monitored && !nsm->sm_sticky) { 185 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name); 186 187 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, host->net); 188 if (res.status != 0) 189 status = -EIO; 190 if (status < 0) 191 printk(KERN_NOTICE "lockd: cannot unmonitor %s\n", 192 nsm->sm_name); 193 else 194 nsm->sm_monitored = 0; 195 } 196 } 197 198 static struct nsm_handle *nsm_lookup_hostname(const char *hostname, 199 const size_t len) 200 { 201 struct nsm_handle *nsm; 202 203 list_for_each_entry(nsm, &nsm_handles, sm_link) 204 if (strlen(nsm->sm_name) == len && 205 memcmp(nsm->sm_name, hostname, len) == 0) 206 return nsm; 207 return NULL; 208 } 209 210 static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap) 211 { 212 struct nsm_handle *nsm; 213 214 list_for_each_entry(nsm, &nsm_handles, sm_link) 215 if (rpc_cmp_addr(nsm_addr(nsm), sap)) 216 return nsm; 217 return NULL; 218 } 219 220 static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv) 221 { 222 struct nsm_handle *nsm; 223 224 list_for_each_entry(nsm, &nsm_handles, sm_link) 225 if (memcmp(nsm->sm_priv.data, priv->data, 226 sizeof(priv->data)) == 0) 227 return nsm; 228 return NULL; 229 } 230 231 /* 232 * Construct a unique cookie to match this nsm_handle to this monitored 233 * host. It is passed to the local rpc.statd via NSMPROC_MON, and 234 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these 235 * requests. 236 * 237 * The NSM protocol requires that these cookies be unique while the 238 * system is running. We prefer a stronger requirement of making them 239 * unique across reboots. If user space bugs cause a stale cookie to 240 * be sent to the kernel, it could cause the wrong host to lose its 241 * lock state if cookies were not unique across reboots. 242 * 243 * The cookies are exposed only to local user space via loopback. They 244 * do not appear on the physical network. If we want greater security 245 * for some reason, nsm_init_private() could perform a one-way hash to 246 * obscure the contents of the cookie. 247 */ 248 static void nsm_init_private(struct nsm_handle *nsm) 249 { 250 u64 *p = (u64 *)&nsm->sm_priv.data; 251 struct timespec ts; 252 s64 ns; 253 254 ktime_get_ts(&ts); 255 ns = timespec_to_ns(&ts); 256 put_unaligned(ns, p); 257 put_unaligned((unsigned long)nsm, p + 1); 258 } 259 260 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 261 const size_t salen, 262 const char *hostname, 263 const size_t hostname_len) 264 { 265 struct nsm_handle *new; 266 267 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL); 268 if (unlikely(new == NULL)) 269 return NULL; 270 271 atomic_set(&new->sm_count, 1); 272 new->sm_name = (char *)(new + 1); 273 memcpy(nsm_addr(new), sap, salen); 274 new->sm_addrlen = salen; 275 nsm_init_private(new); 276 277 if (rpc_ntop(nsm_addr(new), new->sm_addrbuf, 278 sizeof(new->sm_addrbuf)) == 0) 279 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf), 280 "unsupported address family"); 281 memcpy(new->sm_name, hostname, hostname_len); 282 new->sm_name[hostname_len] = '\0'; 283 284 return new; 285 } 286 287 /** 288 * nsm_get_handle - Find or create a cached nsm_handle 289 * @sap: pointer to socket address of handle to find 290 * @salen: length of socket address 291 * @hostname: pointer to C string containing hostname to find 292 * @hostname_len: length of C string 293 * 294 * Behavior is modulated by the global nsm_use_hostnames variable. 295 * 296 * Returns a cached nsm_handle after bumping its ref count, or 297 * returns a fresh nsm_handle if a handle that matches @sap and/or 298 * @hostname cannot be found in the handle cache. Returns NULL if 299 * an error occurs. 300 */ 301 struct nsm_handle *nsm_get_handle(const struct sockaddr *sap, 302 const size_t salen, const char *hostname, 303 const size_t hostname_len) 304 { 305 struct nsm_handle *cached, *new = NULL; 306 307 if (hostname && memchr(hostname, '/', hostname_len) != NULL) { 308 if (printk_ratelimit()) { 309 printk(KERN_WARNING "Invalid hostname \"%.*s\" " 310 "in NFS lock request\n", 311 (int)hostname_len, hostname); 312 } 313 return NULL; 314 } 315 316 retry: 317 spin_lock(&nsm_lock); 318 319 if (nsm_use_hostnames && hostname != NULL) 320 cached = nsm_lookup_hostname(hostname, hostname_len); 321 else 322 cached = nsm_lookup_addr(sap); 323 324 if (cached != NULL) { 325 atomic_inc(&cached->sm_count); 326 spin_unlock(&nsm_lock); 327 kfree(new); 328 dprintk("lockd: found nsm_handle for %s (%s), " 329 "cnt %d\n", cached->sm_name, 330 cached->sm_addrbuf, 331 atomic_read(&cached->sm_count)); 332 return cached; 333 } 334 335 if (new != NULL) { 336 list_add(&new->sm_link, &nsm_handles); 337 spin_unlock(&nsm_lock); 338 dprintk("lockd: created nsm_handle for %s (%s)\n", 339 new->sm_name, new->sm_addrbuf); 340 return new; 341 } 342 343 spin_unlock(&nsm_lock); 344 345 new = nsm_create_handle(sap, salen, hostname, hostname_len); 346 if (unlikely(new == NULL)) 347 return NULL; 348 goto retry; 349 } 350 351 /** 352 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle 353 * @info: pointer to NLMPROC_SM_NOTIFY arguments 354 * 355 * Returns a matching nsm_handle if found in the nsm cache. The returned 356 * nsm_handle's reference count is bumped. Otherwise returns NULL if some 357 * error occurred. 358 */ 359 struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info) 360 { 361 struct nsm_handle *cached; 362 363 spin_lock(&nsm_lock); 364 365 cached = nsm_lookup_priv(&info->priv); 366 if (unlikely(cached == NULL)) { 367 spin_unlock(&nsm_lock); 368 dprintk("lockd: never saw rebooted peer '%.*s' before\n", 369 info->len, info->mon); 370 return cached; 371 } 372 373 atomic_inc(&cached->sm_count); 374 spin_unlock(&nsm_lock); 375 376 dprintk("lockd: host %s (%s) rebooted, cnt %d\n", 377 cached->sm_name, cached->sm_addrbuf, 378 atomic_read(&cached->sm_count)); 379 return cached; 380 } 381 382 /** 383 * nsm_release - Release an NSM handle 384 * @nsm: pointer to handle to be released 385 * 386 */ 387 void nsm_release(struct nsm_handle *nsm) 388 { 389 if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) { 390 list_del(&nsm->sm_link); 391 spin_unlock(&nsm_lock); 392 dprintk("lockd: destroyed nsm_handle for %s (%s)\n", 393 nsm->sm_name, nsm->sm_addrbuf); 394 kfree(nsm); 395 } 396 } 397 398 /* 399 * XDR functions for NSM. 400 * 401 * See http://www.opengroup.org/ for details on the Network 402 * Status Monitor wire protocol. 403 */ 404 405 static void encode_nsm_string(struct xdr_stream *xdr, const char *string) 406 { 407 const u32 len = strlen(string); 408 __be32 *p; 409 410 BUG_ON(len > SM_MAXSTRLEN); 411 p = xdr_reserve_space(xdr, 4 + len); 412 xdr_encode_opaque(p, string, len); 413 } 414 415 /* 416 * "mon_name" specifies the host to be monitored. 417 */ 418 static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp) 419 { 420 encode_nsm_string(xdr, argp->mon_name); 421 } 422 423 /* 424 * The "my_id" argument specifies the hostname and RPC procedure 425 * to be called when the status manager receives notification 426 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" 427 * has changed. 428 */ 429 static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp) 430 { 431 __be32 *p; 432 433 encode_nsm_string(xdr, utsname()->nodename); 434 p = xdr_reserve_space(xdr, 4 + 4 + 4); 435 *p++ = cpu_to_be32(argp->prog); 436 *p++ = cpu_to_be32(argp->vers); 437 *p = cpu_to_be32(argp->proc); 438 } 439 440 /* 441 * The "mon_id" argument specifies the non-private arguments 442 * of an NSMPROC_MON or NSMPROC_UNMON call. 443 */ 444 static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp) 445 { 446 encode_mon_name(xdr, argp); 447 encode_my_id(xdr, argp); 448 } 449 450 /* 451 * The "priv" argument may contain private information required 452 * by the NSMPROC_MON call. This information will be supplied in the 453 * NLMPROC_SM_NOTIFY call. 454 */ 455 static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp) 456 { 457 __be32 *p; 458 459 p = xdr_reserve_space(xdr, SM_PRIV_SIZE); 460 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE); 461 } 462 463 static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr, 464 const struct nsm_args *argp) 465 { 466 encode_mon_id(xdr, argp); 467 encode_priv(xdr, argp); 468 } 469 470 static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr, 471 const struct nsm_args *argp) 472 { 473 encode_mon_id(xdr, argp); 474 } 475 476 static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp, 477 struct xdr_stream *xdr, 478 struct nsm_res *resp) 479 { 480 __be32 *p; 481 482 p = xdr_inline_decode(xdr, 4 + 4); 483 if (unlikely(p == NULL)) 484 return -EIO; 485 resp->status = be32_to_cpup(p++); 486 resp->state = be32_to_cpup(p); 487 488 dprintk("lockd: %s status %d state %d\n", 489 __func__, resp->status, resp->state); 490 return 0; 491 } 492 493 static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp, 494 struct xdr_stream *xdr, 495 struct nsm_res *resp) 496 { 497 __be32 *p; 498 499 p = xdr_inline_decode(xdr, 4); 500 if (unlikely(p == NULL)) 501 return -EIO; 502 resp->state = be32_to_cpup(p); 503 504 dprintk("lockd: %s state %d\n", __func__, resp->state); 505 return 0; 506 } 507 508 #define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 509 #define SM_my_id_sz (SM_my_name_sz+3) 510 #define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 511 #define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz) 512 #define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE)) 513 #define SM_mon_sz (SM_mon_id_sz+SM_priv_sz) 514 #define SM_monres_sz 2 515 #define SM_unmonres_sz 1 516 517 static struct rpc_procinfo nsm_procedures[] = { 518 [NSMPROC_MON] = { 519 .p_proc = NSMPROC_MON, 520 .p_encode = (kxdreproc_t)nsm_xdr_enc_mon, 521 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat_res, 522 .p_arglen = SM_mon_sz, 523 .p_replen = SM_monres_sz, 524 .p_statidx = NSMPROC_MON, 525 .p_name = "MONITOR", 526 }, 527 [NSMPROC_UNMON] = { 528 .p_proc = NSMPROC_UNMON, 529 .p_encode = (kxdreproc_t)nsm_xdr_enc_unmon, 530 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat, 531 .p_arglen = SM_mon_id_sz, 532 .p_replen = SM_unmonres_sz, 533 .p_statidx = NSMPROC_UNMON, 534 .p_name = "UNMONITOR", 535 }, 536 }; 537 538 static const struct rpc_version nsm_version1 = { 539 .number = 1, 540 .nrprocs = ARRAY_SIZE(nsm_procedures), 541 .procs = nsm_procedures 542 }; 543 544 static const struct rpc_version *nsm_version[] = { 545 [1] = &nsm_version1, 546 }; 547 548 static struct rpc_stat nsm_stats; 549 550 static const struct rpc_program nsm_program = { 551 .name = "statd", 552 .number = NSM_PROGRAM, 553 .nrvers = ARRAY_SIZE(nsm_version), 554 .version = nsm_version, 555 .stats = &nsm_stats 556 }; 557