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/kernel.h> 11 #include <linux/ktime.h> 12 #include <linux/slab.h> 13 14 #include <linux/sunrpc/clnt.h> 15 #include <linux/sunrpc/xprtsock.h> 16 #include <linux/sunrpc/svc.h> 17 #include <linux/lockd/lockd.h> 18 19 #include <asm/unaligned.h> 20 21 #include "netns.h" 22 23 #define NLMDBG_FACILITY NLMDBG_MONITOR 24 #define NSM_PROGRAM 100024 25 #define NSM_VERSION 1 26 27 enum { 28 NSMPROC_NULL, 29 NSMPROC_STAT, 30 NSMPROC_MON, 31 NSMPROC_UNMON, 32 NSMPROC_UNMON_ALL, 33 NSMPROC_SIMU_CRASH, 34 NSMPROC_NOTIFY, 35 }; 36 37 struct nsm_args { 38 struct nsm_private *priv; 39 u32 prog; /* RPC callback info */ 40 u32 vers; 41 u32 proc; 42 43 char *mon_name; 44 char *nodename; 45 }; 46 47 struct nsm_res { 48 u32 status; 49 u32 state; 50 }; 51 52 static const struct rpc_program nsm_program; 53 static LIST_HEAD(nsm_handles); 54 static DEFINE_SPINLOCK(nsm_lock); 55 56 /* 57 * Local NSM state 58 */ 59 u32 __read_mostly nsm_local_state; 60 bool __read_mostly nsm_use_hostnames; 61 62 static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm) 63 { 64 return (struct sockaddr *)&nsm->sm_addr; 65 } 66 67 static struct rpc_clnt *nsm_create(struct net *net) 68 { 69 struct sockaddr_in sin = { 70 .sin_family = AF_INET, 71 .sin_addr.s_addr = htonl(INADDR_LOOPBACK), 72 }; 73 struct rpc_create_args args = { 74 .net = net, 75 .protocol = XPRT_TRANSPORT_TCP, 76 .address = (struct sockaddr *)&sin, 77 .addrsize = sizeof(sin), 78 .servername = "rpc.statd", 79 .program = &nsm_program, 80 .version = NSM_VERSION, 81 .authflavor = RPC_AUTH_NULL, 82 .flags = RPC_CLNT_CREATE_NOPING, 83 }; 84 85 return rpc_create(&args); 86 } 87 88 static struct rpc_clnt *nsm_client_set(struct lockd_net *ln, 89 struct rpc_clnt *clnt) 90 { 91 spin_lock(&ln->nsm_clnt_lock); 92 if (ln->nsm_users == 0) { 93 if (clnt == NULL) 94 goto out; 95 ln->nsm_clnt = clnt; 96 } 97 clnt = ln->nsm_clnt; 98 ln->nsm_users++; 99 out: 100 spin_unlock(&ln->nsm_clnt_lock); 101 return clnt; 102 } 103 104 static struct rpc_clnt *nsm_client_get(struct net *net) 105 { 106 struct rpc_clnt *clnt, *new; 107 struct lockd_net *ln = net_generic(net, lockd_net_id); 108 109 clnt = nsm_client_set(ln, NULL); 110 if (clnt != NULL) 111 goto out; 112 113 clnt = new = nsm_create(net); 114 if (IS_ERR(clnt)) 115 goto out; 116 117 clnt = nsm_client_set(ln, new); 118 if (clnt != new) 119 rpc_shutdown_client(new); 120 out: 121 return clnt; 122 } 123 124 static void nsm_client_put(struct net *net) 125 { 126 struct lockd_net *ln = net_generic(net, lockd_net_id); 127 struct rpc_clnt *clnt = NULL; 128 129 spin_lock(&ln->nsm_clnt_lock); 130 ln->nsm_users--; 131 if (ln->nsm_users == 0) { 132 clnt = ln->nsm_clnt; 133 ln->nsm_clnt = NULL; 134 } 135 spin_unlock(&ln->nsm_clnt_lock); 136 if (clnt != NULL) 137 rpc_shutdown_client(clnt); 138 } 139 140 static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res, 141 struct rpc_clnt *clnt) 142 { 143 int status; 144 struct nsm_args args = { 145 .priv = &nsm->sm_priv, 146 .prog = NLM_PROGRAM, 147 .vers = 3, 148 .proc = NLMPROC_NSM_NOTIFY, 149 .mon_name = nsm->sm_mon_name, 150 .nodename = clnt->cl_nodename, 151 }; 152 struct rpc_message msg = { 153 .rpc_argp = &args, 154 .rpc_resp = res, 155 }; 156 157 memset(res, 0, sizeof(*res)); 158 159 msg.rpc_proc = &clnt->cl_procinfo[proc]; 160 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN); 161 if (status < 0) 162 dprintk("lockd: NSM upcall RPC failed, status=%d\n", 163 status); 164 else 165 status = 0; 166 return status; 167 } 168 169 /** 170 * nsm_monitor - Notify a peer in case we reboot 171 * @host: pointer to nlm_host of peer to notify 172 * 173 * If this peer is not already monitored, this function sends an 174 * upcall to the local rpc.statd to record the name/address of 175 * the peer to notify in case we reboot. 176 * 177 * Returns zero if the peer is monitored by the local rpc.statd; 178 * otherwise a negative errno value is returned. 179 */ 180 int nsm_monitor(const struct nlm_host *host) 181 { 182 struct nsm_handle *nsm = host->h_nsmhandle; 183 struct nsm_res res; 184 int status; 185 struct rpc_clnt *clnt; 186 187 dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name); 188 189 if (nsm->sm_monitored) 190 return 0; 191 192 /* 193 * Choose whether to record the caller_name or IP address of 194 * this peer in the local rpc.statd's database. 195 */ 196 nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf; 197 198 clnt = nsm_client_get(host->net); 199 if (IS_ERR(clnt)) { 200 status = PTR_ERR(clnt); 201 dprintk("lockd: failed to create NSM upcall transport, " 202 "status=%d, net=%p\n", status, host->net); 203 return status; 204 } 205 206 status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, clnt); 207 if (unlikely(res.status != 0)) 208 status = -EIO; 209 if (unlikely(status < 0)) { 210 printk(KERN_NOTICE "lockd: cannot monitor %s\n", nsm->sm_name); 211 return status; 212 } 213 214 nsm->sm_monitored = 1; 215 if (unlikely(nsm_local_state != res.state)) { 216 nsm_local_state = res.state; 217 dprintk("lockd: NSM state changed to %d\n", nsm_local_state); 218 } 219 return 0; 220 } 221 222 /** 223 * nsm_unmonitor - Unregister peer notification 224 * @host: pointer to nlm_host of peer to stop monitoring 225 * 226 * If this peer is monitored, this function sends an upcall to 227 * tell the local rpc.statd not to send this peer a notification 228 * when we reboot. 229 */ 230 void nsm_unmonitor(const struct nlm_host *host) 231 { 232 struct nsm_handle *nsm = host->h_nsmhandle; 233 struct nsm_res res; 234 int status; 235 236 if (atomic_read(&nsm->sm_count) == 1 237 && nsm->sm_monitored && !nsm->sm_sticky) { 238 struct lockd_net *ln = net_generic(host->net, lockd_net_id); 239 240 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name); 241 242 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, ln->nsm_clnt); 243 if (res.status != 0) 244 status = -EIO; 245 if (status < 0) 246 printk(KERN_NOTICE "lockd: cannot unmonitor %s\n", 247 nsm->sm_name); 248 else 249 nsm->sm_monitored = 0; 250 251 nsm_client_put(host->net); 252 } 253 } 254 255 static struct nsm_handle *nsm_lookup_hostname(const char *hostname, 256 const size_t len) 257 { 258 struct nsm_handle *nsm; 259 260 list_for_each_entry(nsm, &nsm_handles, sm_link) 261 if (strlen(nsm->sm_name) == len && 262 memcmp(nsm->sm_name, hostname, len) == 0) 263 return nsm; 264 return NULL; 265 } 266 267 static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap) 268 { 269 struct nsm_handle *nsm; 270 271 list_for_each_entry(nsm, &nsm_handles, sm_link) 272 if (rpc_cmp_addr(nsm_addr(nsm), sap)) 273 return nsm; 274 return NULL; 275 } 276 277 static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv) 278 { 279 struct nsm_handle *nsm; 280 281 list_for_each_entry(nsm, &nsm_handles, sm_link) 282 if (memcmp(nsm->sm_priv.data, priv->data, 283 sizeof(priv->data)) == 0) 284 return nsm; 285 return NULL; 286 } 287 288 /* 289 * Construct a unique cookie to match this nsm_handle to this monitored 290 * host. It is passed to the local rpc.statd via NSMPROC_MON, and 291 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these 292 * requests. 293 * 294 * The NSM protocol requires that these cookies be unique while the 295 * system is running. We prefer a stronger requirement of making them 296 * unique across reboots. If user space bugs cause a stale cookie to 297 * be sent to the kernel, it could cause the wrong host to lose its 298 * lock state if cookies were not unique across reboots. 299 * 300 * The cookies are exposed only to local user space via loopback. They 301 * do not appear on the physical network. If we want greater security 302 * for some reason, nsm_init_private() could perform a one-way hash to 303 * obscure the contents of the cookie. 304 */ 305 static void nsm_init_private(struct nsm_handle *nsm) 306 { 307 u64 *p = (u64 *)&nsm->sm_priv.data; 308 struct timespec ts; 309 s64 ns; 310 311 ktime_get_ts(&ts); 312 ns = timespec_to_ns(&ts); 313 put_unaligned(ns, p); 314 put_unaligned((unsigned long)nsm, p + 1); 315 } 316 317 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 318 const size_t salen, 319 const char *hostname, 320 const size_t hostname_len) 321 { 322 struct nsm_handle *new; 323 324 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL); 325 if (unlikely(new == NULL)) 326 return NULL; 327 328 atomic_set(&new->sm_count, 1); 329 new->sm_name = (char *)(new + 1); 330 memcpy(nsm_addr(new), sap, salen); 331 new->sm_addrlen = salen; 332 nsm_init_private(new); 333 334 if (rpc_ntop(nsm_addr(new), new->sm_addrbuf, 335 sizeof(new->sm_addrbuf)) == 0) 336 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf), 337 "unsupported address family"); 338 memcpy(new->sm_name, hostname, hostname_len); 339 new->sm_name[hostname_len] = '\0'; 340 341 return new; 342 } 343 344 /** 345 * nsm_get_handle - Find or create a cached nsm_handle 346 * @sap: pointer to socket address of handle to find 347 * @salen: length of socket address 348 * @hostname: pointer to C string containing hostname to find 349 * @hostname_len: length of C string 350 * 351 * Behavior is modulated by the global nsm_use_hostnames variable. 352 * 353 * Returns a cached nsm_handle after bumping its ref count, or 354 * returns a fresh nsm_handle if a handle that matches @sap and/or 355 * @hostname cannot be found in the handle cache. Returns NULL if 356 * an error occurs. 357 */ 358 struct nsm_handle *nsm_get_handle(const struct sockaddr *sap, 359 const size_t salen, const char *hostname, 360 const size_t hostname_len) 361 { 362 struct nsm_handle *cached, *new = NULL; 363 364 if (hostname && memchr(hostname, '/', hostname_len) != NULL) { 365 if (printk_ratelimit()) { 366 printk(KERN_WARNING "Invalid hostname \"%.*s\" " 367 "in NFS lock request\n", 368 (int)hostname_len, hostname); 369 } 370 return NULL; 371 } 372 373 retry: 374 spin_lock(&nsm_lock); 375 376 if (nsm_use_hostnames && hostname != NULL) 377 cached = nsm_lookup_hostname(hostname, hostname_len); 378 else 379 cached = nsm_lookup_addr(sap); 380 381 if (cached != NULL) { 382 atomic_inc(&cached->sm_count); 383 spin_unlock(&nsm_lock); 384 kfree(new); 385 dprintk("lockd: found nsm_handle for %s (%s), " 386 "cnt %d\n", cached->sm_name, 387 cached->sm_addrbuf, 388 atomic_read(&cached->sm_count)); 389 return cached; 390 } 391 392 if (new != NULL) { 393 list_add(&new->sm_link, &nsm_handles); 394 spin_unlock(&nsm_lock); 395 dprintk("lockd: created nsm_handle for %s (%s)\n", 396 new->sm_name, new->sm_addrbuf); 397 return new; 398 } 399 400 spin_unlock(&nsm_lock); 401 402 new = nsm_create_handle(sap, salen, hostname, hostname_len); 403 if (unlikely(new == NULL)) 404 return NULL; 405 goto retry; 406 } 407 408 /** 409 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle 410 * @info: pointer to NLMPROC_SM_NOTIFY arguments 411 * 412 * Returns a matching nsm_handle if found in the nsm cache. The returned 413 * nsm_handle's reference count is bumped. Otherwise returns NULL if some 414 * error occurred. 415 */ 416 struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info) 417 { 418 struct nsm_handle *cached; 419 420 spin_lock(&nsm_lock); 421 422 cached = nsm_lookup_priv(&info->priv); 423 if (unlikely(cached == NULL)) { 424 spin_unlock(&nsm_lock); 425 dprintk("lockd: never saw rebooted peer '%.*s' before\n", 426 info->len, info->mon); 427 return cached; 428 } 429 430 atomic_inc(&cached->sm_count); 431 spin_unlock(&nsm_lock); 432 433 dprintk("lockd: host %s (%s) rebooted, cnt %d\n", 434 cached->sm_name, cached->sm_addrbuf, 435 atomic_read(&cached->sm_count)); 436 return cached; 437 } 438 439 /** 440 * nsm_release - Release an NSM handle 441 * @nsm: pointer to handle to be released 442 * 443 */ 444 void nsm_release(struct nsm_handle *nsm) 445 { 446 if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) { 447 list_del(&nsm->sm_link); 448 spin_unlock(&nsm_lock); 449 dprintk("lockd: destroyed nsm_handle for %s (%s)\n", 450 nsm->sm_name, nsm->sm_addrbuf); 451 kfree(nsm); 452 } 453 } 454 455 /* 456 * XDR functions for NSM. 457 * 458 * See http://www.opengroup.org/ for details on the Network 459 * Status Monitor wire protocol. 460 */ 461 462 static void encode_nsm_string(struct xdr_stream *xdr, const char *string) 463 { 464 const u32 len = strlen(string); 465 __be32 *p; 466 467 p = xdr_reserve_space(xdr, 4 + len); 468 xdr_encode_opaque(p, string, len); 469 } 470 471 /* 472 * "mon_name" specifies the host to be monitored. 473 */ 474 static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp) 475 { 476 encode_nsm_string(xdr, argp->mon_name); 477 } 478 479 /* 480 * The "my_id" argument specifies the hostname and RPC procedure 481 * to be called when the status manager receives notification 482 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" 483 * has changed. 484 */ 485 static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp) 486 { 487 __be32 *p; 488 489 encode_nsm_string(xdr, argp->nodename); 490 p = xdr_reserve_space(xdr, 4 + 4 + 4); 491 *p++ = cpu_to_be32(argp->prog); 492 *p++ = cpu_to_be32(argp->vers); 493 *p = cpu_to_be32(argp->proc); 494 } 495 496 /* 497 * The "mon_id" argument specifies the non-private arguments 498 * of an NSMPROC_MON or NSMPROC_UNMON call. 499 */ 500 static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp) 501 { 502 encode_mon_name(xdr, argp); 503 encode_my_id(xdr, argp); 504 } 505 506 /* 507 * The "priv" argument may contain private information required 508 * by the NSMPROC_MON call. This information will be supplied in the 509 * NLMPROC_SM_NOTIFY call. 510 */ 511 static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp) 512 { 513 __be32 *p; 514 515 p = xdr_reserve_space(xdr, SM_PRIV_SIZE); 516 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE); 517 } 518 519 static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr, 520 const struct nsm_args *argp) 521 { 522 encode_mon_id(xdr, argp); 523 encode_priv(xdr, argp); 524 } 525 526 static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr, 527 const struct nsm_args *argp) 528 { 529 encode_mon_id(xdr, argp); 530 } 531 532 static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp, 533 struct xdr_stream *xdr, 534 struct nsm_res *resp) 535 { 536 __be32 *p; 537 538 p = xdr_inline_decode(xdr, 4 + 4); 539 if (unlikely(p == NULL)) 540 return -EIO; 541 resp->status = be32_to_cpup(p++); 542 resp->state = be32_to_cpup(p); 543 544 dprintk("lockd: %s status %d state %d\n", 545 __func__, resp->status, resp->state); 546 return 0; 547 } 548 549 static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp, 550 struct xdr_stream *xdr, 551 struct nsm_res *resp) 552 { 553 __be32 *p; 554 555 p = xdr_inline_decode(xdr, 4); 556 if (unlikely(p == NULL)) 557 return -EIO; 558 resp->state = be32_to_cpup(p); 559 560 dprintk("lockd: %s state %d\n", __func__, resp->state); 561 return 0; 562 } 563 564 #define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 565 #define SM_my_id_sz (SM_my_name_sz+3) 566 #define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 567 #define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz) 568 #define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE)) 569 #define SM_mon_sz (SM_mon_id_sz+SM_priv_sz) 570 #define SM_monres_sz 2 571 #define SM_unmonres_sz 1 572 573 static struct rpc_procinfo nsm_procedures[] = { 574 [NSMPROC_MON] = { 575 .p_proc = NSMPROC_MON, 576 .p_encode = (kxdreproc_t)nsm_xdr_enc_mon, 577 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat_res, 578 .p_arglen = SM_mon_sz, 579 .p_replen = SM_monres_sz, 580 .p_statidx = NSMPROC_MON, 581 .p_name = "MONITOR", 582 }, 583 [NSMPROC_UNMON] = { 584 .p_proc = NSMPROC_UNMON, 585 .p_encode = (kxdreproc_t)nsm_xdr_enc_unmon, 586 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat, 587 .p_arglen = SM_mon_id_sz, 588 .p_replen = SM_unmonres_sz, 589 .p_statidx = NSMPROC_UNMON, 590 .p_name = "UNMONITOR", 591 }, 592 }; 593 594 static const struct rpc_version nsm_version1 = { 595 .number = 1, 596 .nrprocs = ARRAY_SIZE(nsm_procedures), 597 .procs = nsm_procedures 598 }; 599 600 static const struct rpc_version *nsm_version[] = { 601 [1] = &nsm_version1, 602 }; 603 604 static struct rpc_stat nsm_stats; 605 606 static const struct rpc_program nsm_program = { 607 .name = "statd", 608 .number = NSM_PROGRAM, 609 .nrvers = ARRAY_SIZE(nsm_version), 610 .version = nsm_version, 611 .stats = &nsm_stats 612 }; 613