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 s64 ns; 310 311 ns = ktime_get_ns(); 312 put_unaligned(ns, p); 313 put_unaligned((unsigned long)nsm, p + 1); 314 } 315 316 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 317 const size_t salen, 318 const char *hostname, 319 const size_t hostname_len) 320 { 321 struct nsm_handle *new; 322 323 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL); 324 if (unlikely(new == NULL)) 325 return NULL; 326 327 atomic_set(&new->sm_count, 1); 328 new->sm_name = (char *)(new + 1); 329 memcpy(nsm_addr(new), sap, salen); 330 new->sm_addrlen = salen; 331 nsm_init_private(new); 332 333 if (rpc_ntop(nsm_addr(new), new->sm_addrbuf, 334 sizeof(new->sm_addrbuf)) == 0) 335 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf), 336 "unsupported address family"); 337 memcpy(new->sm_name, hostname, hostname_len); 338 new->sm_name[hostname_len] = '\0'; 339 340 return new; 341 } 342 343 /** 344 * nsm_get_handle - Find or create a cached nsm_handle 345 * @sap: pointer to socket address of handle to find 346 * @salen: length of socket address 347 * @hostname: pointer to C string containing hostname to find 348 * @hostname_len: length of C string 349 * 350 * Behavior is modulated by the global nsm_use_hostnames variable. 351 * 352 * Returns a cached nsm_handle after bumping its ref count, or 353 * returns a fresh nsm_handle if a handle that matches @sap and/or 354 * @hostname cannot be found in the handle cache. Returns NULL if 355 * an error occurs. 356 */ 357 struct nsm_handle *nsm_get_handle(const struct sockaddr *sap, 358 const size_t salen, const char *hostname, 359 const size_t hostname_len) 360 { 361 struct nsm_handle *cached, *new = NULL; 362 363 if (hostname && memchr(hostname, '/', hostname_len) != NULL) { 364 if (printk_ratelimit()) { 365 printk(KERN_WARNING "Invalid hostname \"%.*s\" " 366 "in NFS lock request\n", 367 (int)hostname_len, hostname); 368 } 369 return NULL; 370 } 371 372 retry: 373 spin_lock(&nsm_lock); 374 375 if (nsm_use_hostnames && hostname != NULL) 376 cached = nsm_lookup_hostname(hostname, hostname_len); 377 else 378 cached = nsm_lookup_addr(sap); 379 380 if (cached != NULL) { 381 atomic_inc(&cached->sm_count); 382 spin_unlock(&nsm_lock); 383 kfree(new); 384 dprintk("lockd: found nsm_handle for %s (%s), " 385 "cnt %d\n", cached->sm_name, 386 cached->sm_addrbuf, 387 atomic_read(&cached->sm_count)); 388 return cached; 389 } 390 391 if (new != NULL) { 392 list_add(&new->sm_link, &nsm_handles); 393 spin_unlock(&nsm_lock); 394 dprintk("lockd: created nsm_handle for %s (%s)\n", 395 new->sm_name, new->sm_addrbuf); 396 return new; 397 } 398 399 spin_unlock(&nsm_lock); 400 401 new = nsm_create_handle(sap, salen, hostname, hostname_len); 402 if (unlikely(new == NULL)) 403 return NULL; 404 goto retry; 405 } 406 407 /** 408 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle 409 * @info: pointer to NLMPROC_SM_NOTIFY arguments 410 * 411 * Returns a matching nsm_handle if found in the nsm cache. The returned 412 * nsm_handle's reference count is bumped. Otherwise returns NULL if some 413 * error occurred. 414 */ 415 struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info) 416 { 417 struct nsm_handle *cached; 418 419 spin_lock(&nsm_lock); 420 421 cached = nsm_lookup_priv(&info->priv); 422 if (unlikely(cached == NULL)) { 423 spin_unlock(&nsm_lock); 424 dprintk("lockd: never saw rebooted peer '%.*s' before\n", 425 info->len, info->mon); 426 return cached; 427 } 428 429 atomic_inc(&cached->sm_count); 430 spin_unlock(&nsm_lock); 431 432 dprintk("lockd: host %s (%s) rebooted, cnt %d\n", 433 cached->sm_name, cached->sm_addrbuf, 434 atomic_read(&cached->sm_count)); 435 return cached; 436 } 437 438 /** 439 * nsm_release - Release an NSM handle 440 * @nsm: pointer to handle to be released 441 * 442 */ 443 void nsm_release(struct nsm_handle *nsm) 444 { 445 if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) { 446 list_del(&nsm->sm_link); 447 spin_unlock(&nsm_lock); 448 dprintk("lockd: destroyed nsm_handle for %s (%s)\n", 449 nsm->sm_name, nsm->sm_addrbuf); 450 kfree(nsm); 451 } 452 } 453 454 /* 455 * XDR functions for NSM. 456 * 457 * See http://www.opengroup.org/ for details on the Network 458 * Status Monitor wire protocol. 459 */ 460 461 static void encode_nsm_string(struct xdr_stream *xdr, const char *string) 462 { 463 const u32 len = strlen(string); 464 __be32 *p; 465 466 p = xdr_reserve_space(xdr, 4 + len); 467 xdr_encode_opaque(p, string, len); 468 } 469 470 /* 471 * "mon_name" specifies the host to be monitored. 472 */ 473 static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp) 474 { 475 encode_nsm_string(xdr, argp->mon_name); 476 } 477 478 /* 479 * The "my_id" argument specifies the hostname and RPC procedure 480 * to be called when the status manager receives notification 481 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" 482 * has changed. 483 */ 484 static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp) 485 { 486 __be32 *p; 487 488 encode_nsm_string(xdr, argp->nodename); 489 p = xdr_reserve_space(xdr, 4 + 4 + 4); 490 *p++ = cpu_to_be32(argp->prog); 491 *p++ = cpu_to_be32(argp->vers); 492 *p = cpu_to_be32(argp->proc); 493 } 494 495 /* 496 * The "mon_id" argument specifies the non-private arguments 497 * of an NSMPROC_MON or NSMPROC_UNMON call. 498 */ 499 static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp) 500 { 501 encode_mon_name(xdr, argp); 502 encode_my_id(xdr, argp); 503 } 504 505 /* 506 * The "priv" argument may contain private information required 507 * by the NSMPROC_MON call. This information will be supplied in the 508 * NLMPROC_SM_NOTIFY call. 509 */ 510 static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp) 511 { 512 __be32 *p; 513 514 p = xdr_reserve_space(xdr, SM_PRIV_SIZE); 515 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE); 516 } 517 518 static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr, 519 const struct nsm_args *argp) 520 { 521 encode_mon_id(xdr, argp); 522 encode_priv(xdr, argp); 523 } 524 525 static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr, 526 const struct nsm_args *argp) 527 { 528 encode_mon_id(xdr, argp); 529 } 530 531 static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp, 532 struct xdr_stream *xdr, 533 struct nsm_res *resp) 534 { 535 __be32 *p; 536 537 p = xdr_inline_decode(xdr, 4 + 4); 538 if (unlikely(p == NULL)) 539 return -EIO; 540 resp->status = be32_to_cpup(p++); 541 resp->state = be32_to_cpup(p); 542 543 dprintk("lockd: %s status %d state %d\n", 544 __func__, resp->status, resp->state); 545 return 0; 546 } 547 548 static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp, 549 struct xdr_stream *xdr, 550 struct nsm_res *resp) 551 { 552 __be32 *p; 553 554 p = xdr_inline_decode(xdr, 4); 555 if (unlikely(p == NULL)) 556 return -EIO; 557 resp->state = be32_to_cpup(p); 558 559 dprintk("lockd: %s state %d\n", __func__, resp->state); 560 return 0; 561 } 562 563 #define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 564 #define SM_my_id_sz (SM_my_name_sz+3) 565 #define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 566 #define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz) 567 #define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE)) 568 #define SM_mon_sz (SM_mon_id_sz+SM_priv_sz) 569 #define SM_monres_sz 2 570 #define SM_unmonres_sz 1 571 572 static struct rpc_procinfo nsm_procedures[] = { 573 [NSMPROC_MON] = { 574 .p_proc = NSMPROC_MON, 575 .p_encode = (kxdreproc_t)nsm_xdr_enc_mon, 576 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat_res, 577 .p_arglen = SM_mon_sz, 578 .p_replen = SM_monres_sz, 579 .p_statidx = NSMPROC_MON, 580 .p_name = "MONITOR", 581 }, 582 [NSMPROC_UNMON] = { 583 .p_proc = NSMPROC_UNMON, 584 .p_encode = (kxdreproc_t)nsm_xdr_enc_unmon, 585 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat, 586 .p_arglen = SM_mon_id_sz, 587 .p_replen = SM_unmonres_sz, 588 .p_statidx = NSMPROC_UNMON, 589 .p_name = "UNMONITOR", 590 }, 591 }; 592 593 static const struct rpc_version nsm_version1 = { 594 .number = 1, 595 .nrprocs = ARRAY_SIZE(nsm_procedures), 596 .procs = nsm_procedures 597 }; 598 599 static const struct rpc_version *nsm_version[] = { 600 [1] = &nsm_version1, 601 }; 602 603 static struct rpc_stat nsm_stats; 604 605 static const struct rpc_program nsm_program = { 606 .name = "statd", 607 .number = NSM_PROGRAM, 608 .nrvers = ARRAY_SIZE(nsm_version), 609 .version = nsm_version, 610 .stats = &nsm_stats 611 }; 612