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/addr.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 #include "netns.h" 23 24 #define NLMDBG_FACILITY NLMDBG_MONITOR 25 #define NSM_PROGRAM 100024 26 #define NSM_VERSION 1 27 28 enum { 29 NSMPROC_NULL, 30 NSMPROC_STAT, 31 NSMPROC_MON, 32 NSMPROC_UNMON, 33 NSMPROC_UNMON_ALL, 34 NSMPROC_SIMU_CRASH, 35 NSMPROC_NOTIFY, 36 }; 37 38 struct nsm_args { 39 struct nsm_private *priv; 40 u32 prog; /* RPC callback info */ 41 u32 vers; 42 u32 proc; 43 44 char *mon_name; 45 char *nodename; 46 }; 47 48 struct nsm_res { 49 u32 status; 50 u32 state; 51 }; 52 53 static const struct rpc_program nsm_program; 54 static LIST_HEAD(nsm_handles); 55 static DEFINE_SPINLOCK(nsm_lock); 56 57 /* 58 * Local NSM state 59 */ 60 u32 __read_mostly nsm_local_state; 61 bool __read_mostly nsm_use_hostnames; 62 63 static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm) 64 { 65 return (struct sockaddr *)&nsm->sm_addr; 66 } 67 68 static struct rpc_clnt *nsm_create(struct net *net) 69 { 70 struct sockaddr_in sin = { 71 .sin_family = AF_INET, 72 .sin_addr.s_addr = htonl(INADDR_LOOPBACK), 73 }; 74 struct rpc_create_args args = { 75 .net = net, 76 .protocol = XPRT_TRANSPORT_TCP, 77 .address = (struct sockaddr *)&sin, 78 .addrsize = sizeof(sin), 79 .servername = "rpc.statd", 80 .program = &nsm_program, 81 .version = NSM_VERSION, 82 .authflavor = RPC_AUTH_NULL, 83 .flags = RPC_CLNT_CREATE_NOPING, 84 }; 85 86 return rpc_create(&args); 87 } 88 89 static struct rpc_clnt *nsm_client_set(struct lockd_net *ln, 90 struct rpc_clnt *clnt) 91 { 92 spin_lock(&ln->nsm_clnt_lock); 93 if (ln->nsm_users == 0) { 94 if (clnt == NULL) 95 goto out; 96 ln->nsm_clnt = clnt; 97 } 98 clnt = ln->nsm_clnt; 99 ln->nsm_users++; 100 out: 101 spin_unlock(&ln->nsm_clnt_lock); 102 return clnt; 103 } 104 105 static struct rpc_clnt *nsm_client_get(struct net *net) 106 { 107 struct rpc_clnt *clnt, *new; 108 struct lockd_net *ln = net_generic(net, lockd_net_id); 109 110 clnt = nsm_client_set(ln, NULL); 111 if (clnt != NULL) 112 goto out; 113 114 clnt = new = nsm_create(net); 115 if (IS_ERR(clnt)) 116 goto out; 117 118 clnt = nsm_client_set(ln, new); 119 if (clnt != new) 120 rpc_shutdown_client(new); 121 out: 122 return clnt; 123 } 124 125 static void nsm_client_put(struct net *net) 126 { 127 struct lockd_net *ln = net_generic(net, lockd_net_id); 128 struct rpc_clnt *clnt = NULL; 129 130 spin_lock(&ln->nsm_clnt_lock); 131 ln->nsm_users--; 132 if (ln->nsm_users == 0) { 133 clnt = ln->nsm_clnt; 134 ln->nsm_clnt = NULL; 135 } 136 spin_unlock(&ln->nsm_clnt_lock); 137 if (clnt != NULL) 138 rpc_shutdown_client(clnt); 139 } 140 141 static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res, 142 struct rpc_clnt *clnt) 143 { 144 int status; 145 struct nsm_args args = { 146 .priv = &nsm->sm_priv, 147 .prog = NLM_PROGRAM, 148 .vers = 3, 149 .proc = NLMPROC_NSM_NOTIFY, 150 .mon_name = nsm->sm_mon_name, 151 .nodename = clnt->cl_nodename, 152 }; 153 struct rpc_message msg = { 154 .rpc_argp = &args, 155 .rpc_resp = res, 156 }; 157 158 memset(res, 0, sizeof(*res)); 159 160 msg.rpc_proc = &clnt->cl_procinfo[proc]; 161 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN); 162 if (status == -ECONNREFUSED) { 163 dprintk("lockd: NSM upcall RPC failed, status=%d, forcing rebind\n", 164 status); 165 rpc_force_rebind(clnt); 166 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN); 167 } 168 if (status < 0) 169 dprintk("lockd: NSM upcall RPC failed, status=%d\n", 170 status); 171 else 172 status = 0; 173 return status; 174 } 175 176 /** 177 * nsm_monitor - Notify a peer in case we reboot 178 * @host: pointer to nlm_host of peer to notify 179 * 180 * If this peer is not already monitored, this function sends an 181 * upcall to the local rpc.statd to record the name/address of 182 * the peer to notify in case we reboot. 183 * 184 * Returns zero if the peer is monitored by the local rpc.statd; 185 * otherwise a negative errno value is returned. 186 */ 187 int nsm_monitor(const struct nlm_host *host) 188 { 189 struct nsm_handle *nsm = host->h_nsmhandle; 190 struct nsm_res res; 191 int status; 192 struct rpc_clnt *clnt; 193 194 dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name); 195 196 if (nsm->sm_monitored) 197 return 0; 198 199 /* 200 * Choose whether to record the caller_name or IP address of 201 * this peer in the local rpc.statd's database. 202 */ 203 nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf; 204 205 clnt = nsm_client_get(host->net); 206 if (IS_ERR(clnt)) { 207 status = PTR_ERR(clnt); 208 dprintk("lockd: failed to create NSM upcall transport, " 209 "status=%d, net=%p\n", status, host->net); 210 return status; 211 } 212 213 status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, clnt); 214 if (unlikely(res.status != 0)) 215 status = -EIO; 216 if (unlikely(status < 0)) { 217 pr_notice_ratelimited("lockd: cannot monitor %s\n", nsm->sm_name); 218 return status; 219 } 220 221 nsm->sm_monitored = 1; 222 if (unlikely(nsm_local_state != res.state)) { 223 nsm_local_state = res.state; 224 dprintk("lockd: NSM state changed to %d\n", nsm_local_state); 225 } 226 return 0; 227 } 228 229 /** 230 * nsm_unmonitor - Unregister peer notification 231 * @host: pointer to nlm_host of peer to stop monitoring 232 * 233 * If this peer is monitored, this function sends an upcall to 234 * tell the local rpc.statd not to send this peer a notification 235 * when we reboot. 236 */ 237 void nsm_unmonitor(const struct nlm_host *host) 238 { 239 struct nsm_handle *nsm = host->h_nsmhandle; 240 struct nsm_res res; 241 int status; 242 243 if (atomic_read(&nsm->sm_count) == 1 244 && nsm->sm_monitored && !nsm->sm_sticky) { 245 struct lockd_net *ln = net_generic(host->net, lockd_net_id); 246 247 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name); 248 249 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, ln->nsm_clnt); 250 if (res.status != 0) 251 status = -EIO; 252 if (status < 0) 253 printk(KERN_NOTICE "lockd: cannot unmonitor %s\n", 254 nsm->sm_name); 255 else 256 nsm->sm_monitored = 0; 257 258 nsm_client_put(host->net); 259 } 260 } 261 262 static struct nsm_handle *nsm_lookup_hostname(const char *hostname, 263 const size_t len) 264 { 265 struct nsm_handle *nsm; 266 267 list_for_each_entry(nsm, &nsm_handles, sm_link) 268 if (strlen(nsm->sm_name) == len && 269 memcmp(nsm->sm_name, hostname, len) == 0) 270 return nsm; 271 return NULL; 272 } 273 274 static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap) 275 { 276 struct nsm_handle *nsm; 277 278 list_for_each_entry(nsm, &nsm_handles, sm_link) 279 if (rpc_cmp_addr(nsm_addr(nsm), sap)) 280 return nsm; 281 return NULL; 282 } 283 284 static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv) 285 { 286 struct nsm_handle *nsm; 287 288 list_for_each_entry(nsm, &nsm_handles, sm_link) 289 if (memcmp(nsm->sm_priv.data, priv->data, 290 sizeof(priv->data)) == 0) 291 return nsm; 292 return NULL; 293 } 294 295 /* 296 * Construct a unique cookie to match this nsm_handle to this monitored 297 * host. It is passed to the local rpc.statd via NSMPROC_MON, and 298 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these 299 * requests. 300 * 301 * The NSM protocol requires that these cookies be unique while the 302 * system is running. We prefer a stronger requirement of making them 303 * unique across reboots. If user space bugs cause a stale cookie to 304 * be sent to the kernel, it could cause the wrong host to lose its 305 * lock state if cookies were not unique across reboots. 306 * 307 * The cookies are exposed only to local user space via loopback. They 308 * do not appear on the physical network. If we want greater security 309 * for some reason, nsm_init_private() could perform a one-way hash to 310 * obscure the contents of the cookie. 311 */ 312 static void nsm_init_private(struct nsm_handle *nsm) 313 { 314 u64 *p = (u64 *)&nsm->sm_priv.data; 315 s64 ns; 316 317 ns = ktime_get_ns(); 318 put_unaligned(ns, p); 319 put_unaligned((unsigned long)nsm, p + 1); 320 } 321 322 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 323 const size_t salen, 324 const char *hostname, 325 const size_t hostname_len) 326 { 327 struct nsm_handle *new; 328 329 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL); 330 if (unlikely(new == NULL)) 331 return NULL; 332 333 atomic_set(&new->sm_count, 1); 334 new->sm_name = (char *)(new + 1); 335 memcpy(nsm_addr(new), sap, salen); 336 new->sm_addrlen = salen; 337 nsm_init_private(new); 338 339 if (rpc_ntop(nsm_addr(new), new->sm_addrbuf, 340 sizeof(new->sm_addrbuf)) == 0) 341 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf), 342 "unsupported address family"); 343 memcpy(new->sm_name, hostname, hostname_len); 344 new->sm_name[hostname_len] = '\0'; 345 346 return new; 347 } 348 349 /** 350 * nsm_get_handle - Find or create a cached nsm_handle 351 * @sap: pointer to socket address of handle to find 352 * @salen: length of socket address 353 * @hostname: pointer to C string containing hostname to find 354 * @hostname_len: length of C string 355 * 356 * Behavior is modulated by the global nsm_use_hostnames variable. 357 * 358 * Returns a cached nsm_handle after bumping its ref count, or 359 * returns a fresh nsm_handle if a handle that matches @sap and/or 360 * @hostname cannot be found in the handle cache. Returns NULL if 361 * an error occurs. 362 */ 363 struct nsm_handle *nsm_get_handle(const struct sockaddr *sap, 364 const size_t salen, const char *hostname, 365 const size_t hostname_len) 366 { 367 struct nsm_handle *cached, *new = NULL; 368 369 if (hostname && memchr(hostname, '/', hostname_len) != NULL) { 370 if (printk_ratelimit()) { 371 printk(KERN_WARNING "Invalid hostname \"%.*s\" " 372 "in NFS lock request\n", 373 (int)hostname_len, hostname); 374 } 375 return NULL; 376 } 377 378 retry: 379 spin_lock(&nsm_lock); 380 381 if (nsm_use_hostnames && hostname != NULL) 382 cached = nsm_lookup_hostname(hostname, hostname_len); 383 else 384 cached = nsm_lookup_addr(sap); 385 386 if (cached != NULL) { 387 atomic_inc(&cached->sm_count); 388 spin_unlock(&nsm_lock); 389 kfree(new); 390 dprintk("lockd: found nsm_handle for %s (%s), " 391 "cnt %d\n", cached->sm_name, 392 cached->sm_addrbuf, 393 atomic_read(&cached->sm_count)); 394 return cached; 395 } 396 397 if (new != NULL) { 398 list_add(&new->sm_link, &nsm_handles); 399 spin_unlock(&nsm_lock); 400 dprintk("lockd: created nsm_handle for %s (%s)\n", 401 new->sm_name, new->sm_addrbuf); 402 return new; 403 } 404 405 spin_unlock(&nsm_lock); 406 407 new = nsm_create_handle(sap, salen, hostname, hostname_len); 408 if (unlikely(new == NULL)) 409 return NULL; 410 goto retry; 411 } 412 413 /** 414 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle 415 * @info: pointer to NLMPROC_SM_NOTIFY arguments 416 * 417 * Returns a matching nsm_handle if found in the nsm cache. The returned 418 * nsm_handle's reference count is bumped. Otherwise returns NULL if some 419 * error occurred. 420 */ 421 struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info) 422 { 423 struct nsm_handle *cached; 424 425 spin_lock(&nsm_lock); 426 427 cached = nsm_lookup_priv(&info->priv); 428 if (unlikely(cached == NULL)) { 429 spin_unlock(&nsm_lock); 430 dprintk("lockd: never saw rebooted peer '%.*s' before\n", 431 info->len, info->mon); 432 return cached; 433 } 434 435 atomic_inc(&cached->sm_count); 436 spin_unlock(&nsm_lock); 437 438 dprintk("lockd: host %s (%s) rebooted, cnt %d\n", 439 cached->sm_name, cached->sm_addrbuf, 440 atomic_read(&cached->sm_count)); 441 return cached; 442 } 443 444 /** 445 * nsm_release - Release an NSM handle 446 * @nsm: pointer to handle to be released 447 * 448 */ 449 void nsm_release(struct nsm_handle *nsm) 450 { 451 if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) { 452 list_del(&nsm->sm_link); 453 spin_unlock(&nsm_lock); 454 dprintk("lockd: destroyed nsm_handle for %s (%s)\n", 455 nsm->sm_name, nsm->sm_addrbuf); 456 kfree(nsm); 457 } 458 } 459 460 /* 461 * XDR functions for NSM. 462 * 463 * See http://www.opengroup.org/ for details on the Network 464 * Status Monitor wire protocol. 465 */ 466 467 static void encode_nsm_string(struct xdr_stream *xdr, const char *string) 468 { 469 const u32 len = strlen(string); 470 __be32 *p; 471 472 p = xdr_reserve_space(xdr, 4 + len); 473 xdr_encode_opaque(p, string, len); 474 } 475 476 /* 477 * "mon_name" specifies the host to be monitored. 478 */ 479 static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp) 480 { 481 encode_nsm_string(xdr, argp->mon_name); 482 } 483 484 /* 485 * The "my_id" argument specifies the hostname and RPC procedure 486 * to be called when the status manager receives notification 487 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" 488 * has changed. 489 */ 490 static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp) 491 { 492 __be32 *p; 493 494 encode_nsm_string(xdr, argp->nodename); 495 p = xdr_reserve_space(xdr, 4 + 4 + 4); 496 *p++ = cpu_to_be32(argp->prog); 497 *p++ = cpu_to_be32(argp->vers); 498 *p = cpu_to_be32(argp->proc); 499 } 500 501 /* 502 * The "mon_id" argument specifies the non-private arguments 503 * of an NSMPROC_MON or NSMPROC_UNMON call. 504 */ 505 static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp) 506 { 507 encode_mon_name(xdr, argp); 508 encode_my_id(xdr, argp); 509 } 510 511 /* 512 * The "priv" argument may contain private information required 513 * by the NSMPROC_MON call. This information will be supplied in the 514 * NLMPROC_SM_NOTIFY call. 515 */ 516 static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp) 517 { 518 __be32 *p; 519 520 p = xdr_reserve_space(xdr, SM_PRIV_SIZE); 521 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE); 522 } 523 524 static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr, 525 const struct nsm_args *argp) 526 { 527 encode_mon_id(xdr, argp); 528 encode_priv(xdr, argp); 529 } 530 531 static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr, 532 const struct nsm_args *argp) 533 { 534 encode_mon_id(xdr, argp); 535 } 536 537 static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp, 538 struct xdr_stream *xdr, 539 struct nsm_res *resp) 540 { 541 __be32 *p; 542 543 p = xdr_inline_decode(xdr, 4 + 4); 544 if (unlikely(p == NULL)) 545 return -EIO; 546 resp->status = be32_to_cpup(p++); 547 resp->state = be32_to_cpup(p); 548 549 dprintk("lockd: %s status %d state %d\n", 550 __func__, resp->status, resp->state); 551 return 0; 552 } 553 554 static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp, 555 struct xdr_stream *xdr, 556 struct nsm_res *resp) 557 { 558 __be32 *p; 559 560 p = xdr_inline_decode(xdr, 4); 561 if (unlikely(p == NULL)) 562 return -EIO; 563 resp->state = be32_to_cpup(p); 564 565 dprintk("lockd: %s state %d\n", __func__, resp->state); 566 return 0; 567 } 568 569 #define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 570 #define SM_my_id_sz (SM_my_name_sz+3) 571 #define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 572 #define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz) 573 #define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE)) 574 #define SM_mon_sz (SM_mon_id_sz+SM_priv_sz) 575 #define SM_monres_sz 2 576 #define SM_unmonres_sz 1 577 578 static struct rpc_procinfo nsm_procedures[] = { 579 [NSMPROC_MON] = { 580 .p_proc = NSMPROC_MON, 581 .p_encode = (kxdreproc_t)nsm_xdr_enc_mon, 582 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat_res, 583 .p_arglen = SM_mon_sz, 584 .p_replen = SM_monres_sz, 585 .p_statidx = NSMPROC_MON, 586 .p_name = "MONITOR", 587 }, 588 [NSMPROC_UNMON] = { 589 .p_proc = NSMPROC_UNMON, 590 .p_encode = (kxdreproc_t)nsm_xdr_enc_unmon, 591 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat, 592 .p_arglen = SM_mon_id_sz, 593 .p_replen = SM_unmonres_sz, 594 .p_statidx = NSMPROC_UNMON, 595 .p_name = "UNMONITOR", 596 }, 597 }; 598 599 static const struct rpc_version nsm_version1 = { 600 .number = 1, 601 .nrprocs = ARRAY_SIZE(nsm_procedures), 602 .procs = nsm_procedures 603 }; 604 605 static const struct rpc_version *nsm_version[] = { 606 [1] = &nsm_version1, 607 }; 608 609 static struct rpc_stat nsm_stats; 610 611 static const struct rpc_program nsm_program = { 612 .name = "statd", 613 .number = NSM_PROGRAM, 614 .nrvers = ARRAY_SIZE(nsm_version), 615 .version = nsm_version, 616 .stats = &nsm_stats 617 }; 618