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/utsname.h> 11 #include <linux/kernel.h> 12 #include <linux/ktime.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 #define NLMDBG_FACILITY NLMDBG_MONITOR 22 #define NSM_PROGRAM 100024 23 #define NSM_VERSION 1 24 25 enum { 26 NSMPROC_NULL, 27 NSMPROC_STAT, 28 NSMPROC_MON, 29 NSMPROC_UNMON, 30 NSMPROC_UNMON_ALL, 31 NSMPROC_SIMU_CRASH, 32 NSMPROC_NOTIFY, 33 }; 34 35 struct nsm_args { 36 struct nsm_private *priv; 37 u32 prog; /* RPC callback info */ 38 u32 vers; 39 u32 proc; 40 41 char *mon_name; 42 }; 43 44 struct nsm_res { 45 u32 status; 46 u32 state; 47 }; 48 49 static struct rpc_program nsm_program; 50 static LIST_HEAD(nsm_handles); 51 static DEFINE_SPINLOCK(nsm_lock); 52 53 /* 54 * Local NSM state 55 */ 56 int __read_mostly nsm_local_state; 57 int __read_mostly nsm_use_hostnames; 58 59 static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm) 60 { 61 return (struct sockaddr *)&nsm->sm_addr; 62 } 63 64 static void nsm_display_ipv4_address(const struct sockaddr *sap, char *buf, 65 const size_t len) 66 { 67 const struct sockaddr_in *sin = (struct sockaddr_in *)sap; 68 snprintf(buf, len, "%pI4", &sin->sin_addr.s_addr); 69 } 70 71 static void nsm_display_ipv6_address(const struct sockaddr *sap, char *buf, 72 const size_t len) 73 { 74 const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap; 75 76 if (ipv6_addr_v4mapped(&sin6->sin6_addr)) 77 snprintf(buf, len, "%pI4", &sin6->sin6_addr.s6_addr32[3]); 78 else if (sin6->sin6_scope_id != 0) 79 snprintf(buf, len, "%pI6%%%u", &sin6->sin6_addr, 80 sin6->sin6_scope_id); 81 else 82 snprintf(buf, len, "%pI6", &sin6->sin6_addr); 83 } 84 85 static void nsm_display_address(const struct sockaddr *sap, 86 char *buf, const size_t len) 87 { 88 switch (sap->sa_family) { 89 case AF_INET: 90 nsm_display_ipv4_address(sap, buf, len); 91 break; 92 case AF_INET6: 93 nsm_display_ipv6_address(sap, buf, len); 94 break; 95 default: 96 snprintf(buf, len, "unsupported address family"); 97 break; 98 } 99 } 100 101 static struct rpc_clnt *nsm_create(void) 102 { 103 struct sockaddr_in sin = { 104 .sin_family = AF_INET, 105 .sin_addr.s_addr = htonl(INADDR_LOOPBACK), 106 }; 107 struct rpc_create_args args = { 108 .protocol = XPRT_TRANSPORT_UDP, 109 .address = (struct sockaddr *)&sin, 110 .addrsize = sizeof(sin), 111 .servername = "rpc.statd", 112 .program = &nsm_program, 113 .version = NSM_VERSION, 114 .authflavor = RPC_AUTH_NULL, 115 }; 116 117 return rpc_create(&args); 118 } 119 120 static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res) 121 { 122 struct rpc_clnt *clnt; 123 int status; 124 struct nsm_args args = { 125 .priv = &nsm->sm_priv, 126 .prog = NLM_PROGRAM, 127 .vers = 3, 128 .proc = NLMPROC_NSM_NOTIFY, 129 .mon_name = nsm->sm_mon_name, 130 }; 131 struct rpc_message msg = { 132 .rpc_argp = &args, 133 .rpc_resp = res, 134 }; 135 136 clnt = nsm_create(); 137 if (IS_ERR(clnt)) { 138 status = PTR_ERR(clnt); 139 dprintk("lockd: failed to create NSM upcall transport, " 140 "status=%d\n", status); 141 goto out; 142 } 143 144 memset(res, 0, sizeof(*res)); 145 146 msg.rpc_proc = &clnt->cl_procinfo[proc]; 147 status = rpc_call_sync(clnt, &msg, 0); 148 if (status < 0) 149 dprintk("lockd: NSM upcall RPC failed, status=%d\n", 150 status); 151 else 152 status = 0; 153 rpc_shutdown_client(clnt); 154 out: 155 return status; 156 } 157 158 /** 159 * nsm_monitor - Notify a peer in case we reboot 160 * @host: pointer to nlm_host of peer to notify 161 * 162 * If this peer is not already monitored, this function sends an 163 * upcall to the local rpc.statd to record the name/address of 164 * the peer to notify in case we reboot. 165 * 166 * Returns zero if the peer is monitored by the local rpc.statd; 167 * otherwise a negative errno value is returned. 168 */ 169 int nsm_monitor(const struct nlm_host *host) 170 { 171 struct nsm_handle *nsm = host->h_nsmhandle; 172 struct nsm_res res; 173 int status; 174 175 dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name); 176 177 if (nsm->sm_monitored) 178 return 0; 179 180 /* 181 * Choose whether to record the caller_name or IP address of 182 * this peer in the local rpc.statd's database. 183 */ 184 nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf; 185 186 status = nsm_mon_unmon(nsm, NSMPROC_MON, &res); 187 if (res.status != 0) 188 status = -EIO; 189 if (status < 0) 190 printk(KERN_NOTICE "lockd: cannot monitor %s\n", nsm->sm_name); 191 else 192 nsm->sm_monitored = 1; 193 return status; 194 } 195 196 /** 197 * nsm_unmonitor - Unregister peer notification 198 * @host: pointer to nlm_host of peer to stop monitoring 199 * 200 * If this peer is monitored, this function sends an upcall to 201 * tell the local rpc.statd not to send this peer a notification 202 * when we reboot. 203 */ 204 void nsm_unmonitor(const struct nlm_host *host) 205 { 206 struct nsm_handle *nsm = host->h_nsmhandle; 207 struct nsm_res res; 208 int status; 209 210 if (atomic_read(&nsm->sm_count) == 1 211 && nsm->sm_monitored && !nsm->sm_sticky) { 212 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name); 213 214 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res); 215 if (res.status != 0) 216 status = -EIO; 217 if (status < 0) 218 printk(KERN_NOTICE "lockd: cannot unmonitor %s\n", 219 nsm->sm_name); 220 else 221 nsm->sm_monitored = 0; 222 } 223 } 224 225 static struct nsm_handle *nsm_lookup_hostname(const char *hostname, 226 const size_t len) 227 { 228 struct nsm_handle *nsm; 229 230 list_for_each_entry(nsm, &nsm_handles, sm_link) 231 if (strlen(nsm->sm_name) == len && 232 memcmp(nsm->sm_name, hostname, len) == 0) 233 return nsm; 234 return NULL; 235 } 236 237 static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap) 238 { 239 struct nsm_handle *nsm; 240 241 list_for_each_entry(nsm, &nsm_handles, sm_link) 242 if (nlm_cmp_addr(nsm_addr(nsm), sap)) 243 return nsm; 244 return NULL; 245 } 246 247 static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv) 248 { 249 struct nsm_handle *nsm; 250 251 list_for_each_entry(nsm, &nsm_handles, sm_link) 252 if (memcmp(nsm->sm_priv.data, priv->data, 253 sizeof(priv->data)) == 0) 254 return nsm; 255 return NULL; 256 } 257 258 /* 259 * Construct a unique cookie to match this nsm_handle to this monitored 260 * host. It is passed to the local rpc.statd via NSMPROC_MON, and 261 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these 262 * requests. 263 * 264 * The NSM protocol requires that these cookies be unique while the 265 * system is running. We prefer a stronger requirement of making them 266 * unique across reboots. If user space bugs cause a stale cookie to 267 * be sent to the kernel, it could cause the wrong host to lose its 268 * lock state if cookies were not unique across reboots. 269 * 270 * The cookies are exposed only to local user space via loopback. They 271 * do not appear on the physical network. If we want greater security 272 * for some reason, nsm_init_private() could perform a one-way hash to 273 * obscure the contents of the cookie. 274 */ 275 static void nsm_init_private(struct nsm_handle *nsm) 276 { 277 u64 *p = (u64 *)&nsm->sm_priv.data; 278 struct timespec ts; 279 s64 ns; 280 281 ktime_get_ts(&ts); 282 ns = timespec_to_ns(&ts); 283 put_unaligned(ns, p); 284 put_unaligned((unsigned long)nsm, p + 1); 285 } 286 287 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 288 const size_t salen, 289 const char *hostname, 290 const size_t hostname_len) 291 { 292 struct nsm_handle *new; 293 294 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL); 295 if (unlikely(new == NULL)) 296 return NULL; 297 298 atomic_set(&new->sm_count, 1); 299 new->sm_name = (char *)(new + 1); 300 memcpy(nsm_addr(new), sap, salen); 301 new->sm_addrlen = salen; 302 nsm_init_private(new); 303 nsm_display_address((const struct sockaddr *)&new->sm_addr, 304 new->sm_addrbuf, sizeof(new->sm_addrbuf)); 305 memcpy(new->sm_name, hostname, hostname_len); 306 new->sm_name[hostname_len] = '\0'; 307 308 return new; 309 } 310 311 /** 312 * nsm_get_handle - Find or create a cached nsm_handle 313 * @sap: pointer to socket address of handle to find 314 * @salen: length of socket address 315 * @hostname: pointer to C string containing hostname to find 316 * @hostname_len: length of C string 317 * 318 * Behavior is modulated by the global nsm_use_hostnames variable. 319 * 320 * Returns a cached nsm_handle after bumping its ref count, or 321 * returns a fresh nsm_handle if a handle that matches @sap and/or 322 * @hostname cannot be found in the handle cache. Returns NULL if 323 * an error occurs. 324 */ 325 struct nsm_handle *nsm_get_handle(const struct sockaddr *sap, 326 const size_t salen, const char *hostname, 327 const size_t hostname_len) 328 { 329 struct nsm_handle *cached, *new = NULL; 330 331 if (hostname && memchr(hostname, '/', hostname_len) != NULL) { 332 if (printk_ratelimit()) { 333 printk(KERN_WARNING "Invalid hostname \"%.*s\" " 334 "in NFS lock request\n", 335 (int)hostname_len, hostname); 336 } 337 return NULL; 338 } 339 340 retry: 341 spin_lock(&nsm_lock); 342 343 if (nsm_use_hostnames && hostname != NULL) 344 cached = nsm_lookup_hostname(hostname, hostname_len); 345 else 346 cached = nsm_lookup_addr(sap); 347 348 if (cached != NULL) { 349 atomic_inc(&cached->sm_count); 350 spin_unlock(&nsm_lock); 351 kfree(new); 352 dprintk("lockd: found nsm_handle for %s (%s), " 353 "cnt %d\n", cached->sm_name, 354 cached->sm_addrbuf, 355 atomic_read(&cached->sm_count)); 356 return cached; 357 } 358 359 if (new != NULL) { 360 list_add(&new->sm_link, &nsm_handles); 361 spin_unlock(&nsm_lock); 362 dprintk("lockd: created nsm_handle for %s (%s)\n", 363 new->sm_name, new->sm_addrbuf); 364 return new; 365 } 366 367 spin_unlock(&nsm_lock); 368 369 new = nsm_create_handle(sap, salen, hostname, hostname_len); 370 if (unlikely(new == NULL)) 371 return NULL; 372 goto retry; 373 } 374 375 /** 376 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle 377 * @info: pointer to NLMPROC_SM_NOTIFY arguments 378 * 379 * Returns a matching nsm_handle if found in the nsm cache; the returned 380 * nsm_handle's reference count is bumped and sm_monitored is cleared. 381 * Otherwise returns NULL if some error occurred. 382 */ 383 struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info) 384 { 385 struct nsm_handle *cached; 386 387 spin_lock(&nsm_lock); 388 389 cached = nsm_lookup_priv(&info->priv); 390 if (unlikely(cached == NULL)) { 391 spin_unlock(&nsm_lock); 392 dprintk("lockd: never saw rebooted peer '%.*s' before\n", 393 info->len, info->mon); 394 return cached; 395 } 396 397 atomic_inc(&cached->sm_count); 398 spin_unlock(&nsm_lock); 399 400 /* 401 * During subsequent lock activity, force a fresh 402 * notification to be set up for this host. 403 */ 404 cached->sm_monitored = 0; 405 406 dprintk("lockd: host %s (%s) rebooted, cnt %d\n", 407 cached->sm_name, cached->sm_addrbuf, 408 atomic_read(&cached->sm_count)); 409 return cached; 410 } 411 412 /** 413 * nsm_release - Release an NSM handle 414 * @nsm: pointer to handle to be released 415 * 416 */ 417 void nsm_release(struct nsm_handle *nsm) 418 { 419 if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) { 420 list_del(&nsm->sm_link); 421 spin_unlock(&nsm_lock); 422 dprintk("lockd: destroyed nsm_handle for %s (%s)\n", 423 nsm->sm_name, nsm->sm_addrbuf); 424 kfree(nsm); 425 } 426 } 427 428 /* 429 * XDR functions for NSM. 430 * 431 * See http://www.opengroup.org/ for details on the Network 432 * Status Monitor wire protocol. 433 */ 434 435 static int encode_nsm_string(struct xdr_stream *xdr, const char *string) 436 { 437 const u32 len = strlen(string); 438 __be32 *p; 439 440 if (unlikely(len > SM_MAXSTRLEN)) 441 return -EIO; 442 p = xdr_reserve_space(xdr, sizeof(u32) + len); 443 if (unlikely(p == NULL)) 444 return -EIO; 445 xdr_encode_opaque(p, string, len); 446 return 0; 447 } 448 449 /* 450 * "mon_name" specifies the host to be monitored. 451 */ 452 static int encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp) 453 { 454 return encode_nsm_string(xdr, argp->mon_name); 455 } 456 457 /* 458 * The "my_id" argument specifies the hostname and RPC procedure 459 * to be called when the status manager receives notification 460 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" 461 * has changed. 462 */ 463 static int encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp) 464 { 465 int status; 466 __be32 *p; 467 468 status = encode_nsm_string(xdr, utsname()->nodename); 469 if (unlikely(status != 0)) 470 return status; 471 p = xdr_reserve_space(xdr, 3 * sizeof(u32)); 472 if (unlikely(p == NULL)) 473 return -EIO; 474 *p++ = htonl(argp->prog); 475 *p++ = htonl(argp->vers); 476 *p++ = htonl(argp->proc); 477 return 0; 478 } 479 480 /* 481 * The "mon_id" argument specifies the non-private arguments 482 * of an NSMPROC_MON or NSMPROC_UNMON call. 483 */ 484 static int encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp) 485 { 486 int status; 487 488 status = encode_mon_name(xdr, argp); 489 if (unlikely(status != 0)) 490 return status; 491 return encode_my_id(xdr, argp); 492 } 493 494 /* 495 * The "priv" argument may contain private information required 496 * by the NSMPROC_MON call. This information will be supplied in the 497 * NLMPROC_SM_NOTIFY call. 498 */ 499 static int encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp) 500 { 501 __be32 *p; 502 503 p = xdr_reserve_space(xdr, SM_PRIV_SIZE); 504 if (unlikely(p == NULL)) 505 return -EIO; 506 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE); 507 return 0; 508 } 509 510 static int xdr_enc_mon(struct rpc_rqst *req, __be32 *p, 511 const struct nsm_args *argp) 512 { 513 struct xdr_stream xdr; 514 int status; 515 516 xdr_init_encode(&xdr, &req->rq_snd_buf, p); 517 status = encode_mon_id(&xdr, argp); 518 if (unlikely(status)) 519 return status; 520 return encode_priv(&xdr, argp); 521 } 522 523 static int xdr_enc_unmon(struct rpc_rqst *req, __be32 *p, 524 const struct nsm_args *argp) 525 { 526 struct xdr_stream xdr; 527 528 xdr_init_encode(&xdr, &req->rq_snd_buf, p); 529 return encode_mon_id(&xdr, argp); 530 } 531 532 static int xdr_dec_stat_res(struct rpc_rqst *rqstp, __be32 *p, 533 struct nsm_res *resp) 534 { 535 struct xdr_stream xdr; 536 537 xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p); 538 p = xdr_inline_decode(&xdr, 2 * sizeof(u32)); 539 if (unlikely(p == NULL)) 540 return -EIO; 541 resp->status = ntohl(*p++); 542 resp->state = ntohl(*p); 543 544 dprintk("lockd: xdr_dec_stat_res status %d state %d\n", 545 resp->status, resp->state); 546 return 0; 547 } 548 549 static int xdr_dec_stat(struct rpc_rqst *rqstp, __be32 *p, 550 struct nsm_res *resp) 551 { 552 struct xdr_stream xdr; 553 554 xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p); 555 p = xdr_inline_decode(&xdr, sizeof(u32)); 556 if (unlikely(p == NULL)) 557 return -EIO; 558 resp->state = ntohl(*p); 559 560 dprintk("lockd: xdr_dec_stat state %d\n", 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 = (kxdrproc_t)xdr_enc_mon, 577 .p_decode = (kxdrproc_t)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 = (kxdrproc_t)xdr_enc_unmon, 586 .p_decode = (kxdrproc_t)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 struct rpc_version nsm_version1 = { 595 .number = 1, 596 .nrprocs = ARRAY_SIZE(nsm_procedures), 597 .procs = nsm_procedures 598 }; 599 600 static struct rpc_version * nsm_version[] = { 601 [1] = &nsm_version1, 602 }; 603 604 static struct rpc_stat nsm_stats; 605 606 static 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