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, const char *nodename) 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 .nodename = nodename, 81 .program = &nsm_program, 82 .version = NSM_VERSION, 83 .authflavor = RPC_AUTH_NULL, 84 .flags = RPC_CLNT_CREATE_NOPING, 85 }; 86 87 return rpc_create(&args); 88 } 89 90 static struct rpc_clnt *nsm_client_set(struct lockd_net *ln, 91 struct rpc_clnt *clnt) 92 { 93 spin_lock(&ln->nsm_clnt_lock); 94 if (ln->nsm_users == 0) { 95 if (clnt == NULL) 96 goto out; 97 ln->nsm_clnt = clnt; 98 } 99 clnt = ln->nsm_clnt; 100 ln->nsm_users++; 101 out: 102 spin_unlock(&ln->nsm_clnt_lock); 103 return clnt; 104 } 105 106 static struct rpc_clnt *nsm_client_get(struct net *net, const char *nodename) 107 { 108 struct rpc_clnt *clnt, *new; 109 struct lockd_net *ln = net_generic(net, lockd_net_id); 110 111 clnt = nsm_client_set(ln, NULL); 112 if (clnt != NULL) 113 goto out; 114 115 clnt = new = nsm_create(net, nodename); 116 if (IS_ERR(clnt)) 117 goto out; 118 119 clnt = nsm_client_set(ln, new); 120 if (clnt != new) 121 rpc_shutdown_client(new); 122 out: 123 return clnt; 124 } 125 126 static void nsm_client_put(struct net *net) 127 { 128 struct lockd_net *ln = net_generic(net, lockd_net_id); 129 struct rpc_clnt *clnt = NULL; 130 131 spin_lock(&ln->nsm_clnt_lock); 132 ln->nsm_users--; 133 if (ln->nsm_users == 0) { 134 clnt = ln->nsm_clnt; 135 ln->nsm_clnt = NULL; 136 } 137 spin_unlock(&ln->nsm_clnt_lock); 138 if (clnt != NULL) 139 rpc_shutdown_client(clnt); 140 } 141 142 static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res, 143 struct rpc_clnt *clnt) 144 { 145 int status; 146 struct nsm_args args = { 147 .priv = &nsm->sm_priv, 148 .prog = NLM_PROGRAM, 149 .vers = 3, 150 .proc = NLMPROC_NSM_NOTIFY, 151 .mon_name = nsm->sm_mon_name, 152 .nodename = clnt->cl_nodename, 153 }; 154 struct rpc_message msg = { 155 .rpc_argp = &args, 156 .rpc_resp = res, 157 }; 158 159 memset(res, 0, sizeof(*res)); 160 161 msg.rpc_proc = &clnt->cl_procinfo[proc]; 162 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN); 163 if (status == -ECONNREFUSED) { 164 dprintk("lockd: NSM upcall RPC failed, status=%d, forcing rebind\n", 165 status); 166 rpc_force_rebind(clnt); 167 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN); 168 } 169 if (status < 0) 170 dprintk("lockd: NSM upcall RPC failed, status=%d\n", 171 status); 172 else 173 status = 0; 174 return status; 175 } 176 177 /** 178 * nsm_monitor - Notify a peer in case we reboot 179 * @host: pointer to nlm_host of peer to notify 180 * 181 * If this peer is not already monitored, this function sends an 182 * upcall to the local rpc.statd to record the name/address of 183 * the peer to notify in case we reboot. 184 * 185 * Returns zero if the peer is monitored by the local rpc.statd; 186 * otherwise a negative errno value is returned. 187 */ 188 int nsm_monitor(const struct nlm_host *host) 189 { 190 struct nsm_handle *nsm = host->h_nsmhandle; 191 struct nsm_res res; 192 int status; 193 struct rpc_clnt *clnt; 194 const char *nodename = NULL; 195 196 dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name); 197 198 if (nsm->sm_monitored) 199 return 0; 200 201 if (host->h_rpcclnt) 202 nodename = host->h_rpcclnt->cl_nodename; 203 204 /* 205 * Choose whether to record the caller_name or IP address of 206 * this peer in the local rpc.statd's database. 207 */ 208 nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf; 209 210 clnt = nsm_client_get(host->net, nodename); 211 if (IS_ERR(clnt)) { 212 status = PTR_ERR(clnt); 213 dprintk("lockd: failed to create NSM upcall transport, " 214 "status=%d, net=%p\n", status, host->net); 215 return status; 216 } 217 218 status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, clnt); 219 if (unlikely(res.status != 0)) 220 status = -EIO; 221 if (unlikely(status < 0)) { 222 pr_notice_ratelimited("lockd: cannot monitor %s\n", nsm->sm_name); 223 return status; 224 } 225 226 nsm->sm_monitored = 1; 227 if (unlikely(nsm_local_state != res.state)) { 228 nsm_local_state = res.state; 229 dprintk("lockd: NSM state changed to %d\n", nsm_local_state); 230 } 231 return 0; 232 } 233 234 /** 235 * nsm_unmonitor - Unregister peer notification 236 * @host: pointer to nlm_host of peer to stop monitoring 237 * 238 * If this peer is monitored, this function sends an upcall to 239 * tell the local rpc.statd not to send this peer a notification 240 * when we reboot. 241 */ 242 void nsm_unmonitor(const struct nlm_host *host) 243 { 244 struct nsm_handle *nsm = host->h_nsmhandle; 245 struct nsm_res res; 246 int status; 247 248 if (atomic_read(&nsm->sm_count) == 1 249 && nsm->sm_monitored && !nsm->sm_sticky) { 250 struct lockd_net *ln = net_generic(host->net, lockd_net_id); 251 252 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name); 253 254 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, ln->nsm_clnt); 255 if (res.status != 0) 256 status = -EIO; 257 if (status < 0) 258 printk(KERN_NOTICE "lockd: cannot unmonitor %s\n", 259 nsm->sm_name); 260 else 261 nsm->sm_monitored = 0; 262 263 nsm_client_put(host->net); 264 } 265 } 266 267 static struct nsm_handle *nsm_lookup_hostname(const char *hostname, 268 const size_t len) 269 { 270 struct nsm_handle *nsm; 271 272 list_for_each_entry(nsm, &nsm_handles, sm_link) 273 if (strlen(nsm->sm_name) == len && 274 memcmp(nsm->sm_name, hostname, len) == 0) 275 return nsm; 276 return NULL; 277 } 278 279 static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap) 280 { 281 struct nsm_handle *nsm; 282 283 list_for_each_entry(nsm, &nsm_handles, sm_link) 284 if (rpc_cmp_addr(nsm_addr(nsm), sap)) 285 return nsm; 286 return NULL; 287 } 288 289 static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv) 290 { 291 struct nsm_handle *nsm; 292 293 list_for_each_entry(nsm, &nsm_handles, sm_link) 294 if (memcmp(nsm->sm_priv.data, priv->data, 295 sizeof(priv->data)) == 0) 296 return nsm; 297 return NULL; 298 } 299 300 /* 301 * Construct a unique cookie to match this nsm_handle to this monitored 302 * host. It is passed to the local rpc.statd via NSMPROC_MON, and 303 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these 304 * requests. 305 * 306 * The NSM protocol requires that these cookies be unique while the 307 * system is running. We prefer a stronger requirement of making them 308 * unique across reboots. If user space bugs cause a stale cookie to 309 * be sent to the kernel, it could cause the wrong host to lose its 310 * lock state if cookies were not unique across reboots. 311 * 312 * The cookies are exposed only to local user space via loopback. They 313 * do not appear on the physical network. If we want greater security 314 * for some reason, nsm_init_private() could perform a one-way hash to 315 * obscure the contents of the cookie. 316 */ 317 static void nsm_init_private(struct nsm_handle *nsm) 318 { 319 u64 *p = (u64 *)&nsm->sm_priv.data; 320 s64 ns; 321 322 ns = ktime_get_ns(); 323 put_unaligned(ns, p); 324 put_unaligned((unsigned long)nsm, p + 1); 325 } 326 327 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 328 const size_t salen, 329 const char *hostname, 330 const size_t hostname_len) 331 { 332 struct nsm_handle *new; 333 334 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL); 335 if (unlikely(new == NULL)) 336 return NULL; 337 338 atomic_set(&new->sm_count, 1); 339 new->sm_name = (char *)(new + 1); 340 memcpy(nsm_addr(new), sap, salen); 341 new->sm_addrlen = salen; 342 nsm_init_private(new); 343 344 if (rpc_ntop(nsm_addr(new), new->sm_addrbuf, 345 sizeof(new->sm_addrbuf)) == 0) 346 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf), 347 "unsupported address family"); 348 memcpy(new->sm_name, hostname, hostname_len); 349 new->sm_name[hostname_len] = '\0'; 350 351 return new; 352 } 353 354 /** 355 * nsm_get_handle - Find or create a cached nsm_handle 356 * @sap: pointer to socket address of handle to find 357 * @salen: length of socket address 358 * @hostname: pointer to C string containing hostname to find 359 * @hostname_len: length of C string 360 * 361 * Behavior is modulated by the global nsm_use_hostnames variable. 362 * 363 * Returns a cached nsm_handle after bumping its ref count, or 364 * returns a fresh nsm_handle if a handle that matches @sap and/or 365 * @hostname cannot be found in the handle cache. Returns NULL if 366 * an error occurs. 367 */ 368 struct nsm_handle *nsm_get_handle(const struct sockaddr *sap, 369 const size_t salen, const char *hostname, 370 const size_t hostname_len) 371 { 372 struct nsm_handle *cached, *new = NULL; 373 374 if (hostname && memchr(hostname, '/', hostname_len) != NULL) { 375 if (printk_ratelimit()) { 376 printk(KERN_WARNING "Invalid hostname \"%.*s\" " 377 "in NFS lock request\n", 378 (int)hostname_len, hostname); 379 } 380 return NULL; 381 } 382 383 retry: 384 spin_lock(&nsm_lock); 385 386 if (nsm_use_hostnames && hostname != NULL) 387 cached = nsm_lookup_hostname(hostname, hostname_len); 388 else 389 cached = nsm_lookup_addr(sap); 390 391 if (cached != NULL) { 392 atomic_inc(&cached->sm_count); 393 spin_unlock(&nsm_lock); 394 kfree(new); 395 dprintk("lockd: found nsm_handle for %s (%s), " 396 "cnt %d\n", cached->sm_name, 397 cached->sm_addrbuf, 398 atomic_read(&cached->sm_count)); 399 return cached; 400 } 401 402 if (new != NULL) { 403 list_add(&new->sm_link, &nsm_handles); 404 spin_unlock(&nsm_lock); 405 dprintk("lockd: created nsm_handle for %s (%s)\n", 406 new->sm_name, new->sm_addrbuf); 407 return new; 408 } 409 410 spin_unlock(&nsm_lock); 411 412 new = nsm_create_handle(sap, salen, hostname, hostname_len); 413 if (unlikely(new == NULL)) 414 return NULL; 415 goto retry; 416 } 417 418 /** 419 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle 420 * @info: pointer to NLMPROC_SM_NOTIFY arguments 421 * 422 * Returns a matching nsm_handle if found in the nsm cache. The returned 423 * nsm_handle's reference count is bumped. Otherwise returns NULL if some 424 * error occurred. 425 */ 426 struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info) 427 { 428 struct nsm_handle *cached; 429 430 spin_lock(&nsm_lock); 431 432 cached = nsm_lookup_priv(&info->priv); 433 if (unlikely(cached == NULL)) { 434 spin_unlock(&nsm_lock); 435 dprintk("lockd: never saw rebooted peer '%.*s' before\n", 436 info->len, info->mon); 437 return cached; 438 } 439 440 atomic_inc(&cached->sm_count); 441 spin_unlock(&nsm_lock); 442 443 dprintk("lockd: host %s (%s) rebooted, cnt %d\n", 444 cached->sm_name, cached->sm_addrbuf, 445 atomic_read(&cached->sm_count)); 446 return cached; 447 } 448 449 /** 450 * nsm_release - Release an NSM handle 451 * @nsm: pointer to handle to be released 452 * 453 */ 454 void nsm_release(struct nsm_handle *nsm) 455 { 456 if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) { 457 list_del(&nsm->sm_link); 458 spin_unlock(&nsm_lock); 459 dprintk("lockd: destroyed nsm_handle for %s (%s)\n", 460 nsm->sm_name, nsm->sm_addrbuf); 461 kfree(nsm); 462 } 463 } 464 465 /* 466 * XDR functions for NSM. 467 * 468 * See http://www.opengroup.org/ for details on the Network 469 * Status Monitor wire protocol. 470 */ 471 472 static void encode_nsm_string(struct xdr_stream *xdr, const char *string) 473 { 474 const u32 len = strlen(string); 475 __be32 *p; 476 477 p = xdr_reserve_space(xdr, 4 + len); 478 xdr_encode_opaque(p, string, len); 479 } 480 481 /* 482 * "mon_name" specifies the host to be monitored. 483 */ 484 static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp) 485 { 486 encode_nsm_string(xdr, argp->mon_name); 487 } 488 489 /* 490 * The "my_id" argument specifies the hostname and RPC procedure 491 * to be called when the status manager receives notification 492 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" 493 * has changed. 494 */ 495 static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp) 496 { 497 __be32 *p; 498 499 encode_nsm_string(xdr, argp->nodename); 500 p = xdr_reserve_space(xdr, 4 + 4 + 4); 501 *p++ = cpu_to_be32(argp->prog); 502 *p++ = cpu_to_be32(argp->vers); 503 *p = cpu_to_be32(argp->proc); 504 } 505 506 /* 507 * The "mon_id" argument specifies the non-private arguments 508 * of an NSMPROC_MON or NSMPROC_UNMON call. 509 */ 510 static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp) 511 { 512 encode_mon_name(xdr, argp); 513 encode_my_id(xdr, argp); 514 } 515 516 /* 517 * The "priv" argument may contain private information required 518 * by the NSMPROC_MON call. This information will be supplied in the 519 * NLMPROC_SM_NOTIFY call. 520 */ 521 static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp) 522 { 523 __be32 *p; 524 525 p = xdr_reserve_space(xdr, SM_PRIV_SIZE); 526 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE); 527 } 528 529 static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr, 530 const struct nsm_args *argp) 531 { 532 encode_mon_id(xdr, argp); 533 encode_priv(xdr, argp); 534 } 535 536 static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr, 537 const struct nsm_args *argp) 538 { 539 encode_mon_id(xdr, argp); 540 } 541 542 static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp, 543 struct xdr_stream *xdr, 544 struct nsm_res *resp) 545 { 546 __be32 *p; 547 548 p = xdr_inline_decode(xdr, 4 + 4); 549 if (unlikely(p == NULL)) 550 return -EIO; 551 resp->status = be32_to_cpup(p++); 552 resp->state = be32_to_cpup(p); 553 554 dprintk("lockd: %s status %d state %d\n", 555 __func__, resp->status, resp->state); 556 return 0; 557 } 558 559 static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp, 560 struct xdr_stream *xdr, 561 struct nsm_res *resp) 562 { 563 __be32 *p; 564 565 p = xdr_inline_decode(xdr, 4); 566 if (unlikely(p == NULL)) 567 return -EIO; 568 resp->state = be32_to_cpup(p); 569 570 dprintk("lockd: %s state %d\n", __func__, resp->state); 571 return 0; 572 } 573 574 #define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 575 #define SM_my_id_sz (SM_my_name_sz+3) 576 #define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 577 #define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz) 578 #define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE)) 579 #define SM_mon_sz (SM_mon_id_sz+SM_priv_sz) 580 #define SM_monres_sz 2 581 #define SM_unmonres_sz 1 582 583 static struct rpc_procinfo nsm_procedures[] = { 584 [NSMPROC_MON] = { 585 .p_proc = NSMPROC_MON, 586 .p_encode = (kxdreproc_t)nsm_xdr_enc_mon, 587 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat_res, 588 .p_arglen = SM_mon_sz, 589 .p_replen = SM_monres_sz, 590 .p_statidx = NSMPROC_MON, 591 .p_name = "MONITOR", 592 }, 593 [NSMPROC_UNMON] = { 594 .p_proc = NSMPROC_UNMON, 595 .p_encode = (kxdreproc_t)nsm_xdr_enc_unmon, 596 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat, 597 .p_arglen = SM_mon_id_sz, 598 .p_replen = SM_unmonres_sz, 599 .p_statidx = NSMPROC_UNMON, 600 .p_name = "UNMONITOR", 601 }, 602 }; 603 604 static const struct rpc_version nsm_version1 = { 605 .number = 1, 606 .nrprocs = ARRAY_SIZE(nsm_procedures), 607 .procs = nsm_procedures 608 }; 609 610 static const struct rpc_version *nsm_version[] = { 611 [1] = &nsm_version1, 612 }; 613 614 static struct rpc_stat nsm_stats; 615 616 static const struct rpc_program nsm_program = { 617 .name = "statd", 618 .number = NSM_PROGRAM, 619 .nrvers = ARRAY_SIZE(nsm_version), 620 .version = nsm_version, 621 .stats = &nsm_stats 622 }; 623