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