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 #define NLMDBG_FACILITY NLMDBG_MONITOR 20 #define NSM_PROGRAM 100024 21 #define NSM_VERSION 1 22 23 enum { 24 NSMPROC_NULL, 25 NSMPROC_STAT, 26 NSMPROC_MON, 27 NSMPROC_UNMON, 28 NSMPROC_UNMON_ALL, 29 NSMPROC_SIMU_CRASH, 30 NSMPROC_NOTIFY, 31 }; 32 33 struct nsm_args { 34 struct nsm_private *priv; 35 u32 prog; /* RPC callback info */ 36 u32 vers; 37 u32 proc; 38 39 char *mon_name; 40 }; 41 42 struct nsm_res { 43 u32 status; 44 u32 state; 45 }; 46 47 static struct rpc_program nsm_program; 48 static LIST_HEAD(nsm_handles); 49 static DEFINE_SPINLOCK(nsm_lock); 50 51 /* 52 * Local NSM state 53 */ 54 int __read_mostly nsm_local_state; 55 int __read_mostly nsm_use_hostnames; 56 57 static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm) 58 { 59 return (struct sockaddr *)&nsm->sm_addr; 60 } 61 62 static void nsm_display_ipv4_address(const struct sockaddr *sap, char *buf, 63 const size_t len) 64 { 65 const struct sockaddr_in *sin = (struct sockaddr_in *)sap; 66 snprintf(buf, len, "%pI4", &sin->sin_addr.s_addr); 67 } 68 69 static void nsm_display_ipv6_address(const struct sockaddr *sap, char *buf, 70 const size_t len) 71 { 72 const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap; 73 74 if (ipv6_addr_v4mapped(&sin6->sin6_addr)) 75 snprintf(buf, len, "%pI4", &sin6->sin6_addr.s6_addr32[3]); 76 else if (sin6->sin6_scope_id != 0) 77 snprintf(buf, len, "%pI6%%%u", &sin6->sin6_addr, 78 sin6->sin6_scope_id); 79 else 80 snprintf(buf, len, "%pI6", &sin6->sin6_addr); 81 } 82 83 static void nsm_display_address(const struct sockaddr *sap, 84 char *buf, const size_t len) 85 { 86 switch (sap->sa_family) { 87 case AF_INET: 88 nsm_display_ipv4_address(sap, buf, len); 89 break; 90 case AF_INET6: 91 nsm_display_ipv6_address(sap, buf, len); 92 break; 93 default: 94 snprintf(buf, len, "unsupported address family"); 95 break; 96 } 97 } 98 99 static struct rpc_clnt *nsm_create(void) 100 { 101 struct sockaddr_in sin = { 102 .sin_family = AF_INET, 103 .sin_addr.s_addr = htonl(INADDR_LOOPBACK), 104 }; 105 struct rpc_create_args args = { 106 .protocol = XPRT_TRANSPORT_UDP, 107 .address = (struct sockaddr *)&sin, 108 .addrsize = sizeof(sin), 109 .servername = "rpc.statd", 110 .program = &nsm_program, 111 .version = NSM_VERSION, 112 .authflavor = RPC_AUTH_NULL, 113 }; 114 115 return rpc_create(&args); 116 } 117 118 static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res) 119 { 120 struct rpc_clnt *clnt; 121 int status; 122 struct nsm_args args = { 123 .priv = &nsm->sm_priv, 124 .prog = NLM_PROGRAM, 125 .vers = 3, 126 .proc = NLMPROC_NSM_NOTIFY, 127 .mon_name = nsm->sm_mon_name, 128 }; 129 struct rpc_message msg = { 130 .rpc_argp = &args, 131 .rpc_resp = res, 132 }; 133 134 clnt = nsm_create(); 135 if (IS_ERR(clnt)) { 136 status = PTR_ERR(clnt); 137 dprintk("lockd: failed to create NSM upcall transport, " 138 "status=%d\n", status); 139 goto out; 140 } 141 142 memset(res, 0, sizeof(*res)); 143 144 msg.rpc_proc = &clnt->cl_procinfo[proc]; 145 status = rpc_call_sync(clnt, &msg, 0); 146 if (status < 0) 147 dprintk("lockd: NSM upcall RPC failed, status=%d\n", 148 status); 149 else 150 status = 0; 151 rpc_shutdown_client(clnt); 152 out: 153 return status; 154 } 155 156 /** 157 * nsm_monitor - Notify a peer in case we reboot 158 * @host: pointer to nlm_host of peer to notify 159 * 160 * If this peer is not already monitored, this function sends an 161 * upcall to the local rpc.statd to record the name/address of 162 * the peer to notify in case we reboot. 163 * 164 * Returns zero if the peer is monitored by the local rpc.statd; 165 * otherwise a negative errno value is returned. 166 */ 167 int nsm_monitor(const struct nlm_host *host) 168 { 169 struct nsm_handle *nsm = host->h_nsmhandle; 170 struct nsm_res res; 171 int status; 172 173 dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name); 174 175 if (nsm->sm_monitored) 176 return 0; 177 178 /* 179 * Choose whether to record the caller_name or IP address of 180 * this peer in the local rpc.statd's database. 181 */ 182 nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf; 183 184 status = nsm_mon_unmon(nsm, NSMPROC_MON, &res); 185 if (res.status != 0) 186 status = -EIO; 187 if (status < 0) 188 printk(KERN_NOTICE "lockd: cannot monitor %s\n", nsm->sm_name); 189 else 190 nsm->sm_monitored = 1; 191 return status; 192 } 193 194 /** 195 * nsm_unmonitor - Unregister peer notification 196 * @host: pointer to nlm_host of peer to stop monitoring 197 * 198 * If this peer is monitored, this function sends an upcall to 199 * tell the local rpc.statd not to send this peer a notification 200 * when we reboot. 201 */ 202 void nsm_unmonitor(const struct nlm_host *host) 203 { 204 struct nsm_handle *nsm = host->h_nsmhandle; 205 struct nsm_res res; 206 int status; 207 208 if (atomic_read(&nsm->sm_count) == 1 209 && nsm->sm_monitored && !nsm->sm_sticky) { 210 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name); 211 212 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res); 213 if (res.status != 0) 214 status = -EIO; 215 if (status < 0) 216 printk(KERN_NOTICE "lockd: cannot unmonitor %s\n", 217 nsm->sm_name); 218 else 219 nsm->sm_monitored = 0; 220 } 221 } 222 223 static struct nsm_handle *nsm_lookup_hostname(const char *hostname, 224 const size_t len) 225 { 226 struct nsm_handle *nsm; 227 228 list_for_each_entry(nsm, &nsm_handles, sm_link) 229 if (strlen(nsm->sm_name) == len && 230 memcmp(nsm->sm_name, hostname, len) == 0) 231 return nsm; 232 return NULL; 233 } 234 235 static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap) 236 { 237 struct nsm_handle *nsm; 238 239 list_for_each_entry(nsm, &nsm_handles, sm_link) 240 if (nlm_cmp_addr(nsm_addr(nsm), sap)) 241 return nsm; 242 return NULL; 243 } 244 245 static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv) 246 { 247 struct nsm_handle *nsm; 248 249 list_for_each_entry(nsm, &nsm_handles, sm_link) 250 if (memcmp(nsm->sm_priv.data, priv->data, 251 sizeof(priv->data)) == 0) 252 return nsm; 253 return NULL; 254 } 255 256 /* 257 * Construct a unique cookie to match this nsm_handle to this monitored 258 * host. It is passed to the local rpc.statd via NSMPROC_MON, and 259 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these 260 * requests. 261 * 262 * The NSM protocol requires that these cookies be unique while the 263 * system is running. We prefer a stronger requirement of making them 264 * unique across reboots. If user space bugs cause a stale cookie to 265 * be sent to the kernel, it could cause the wrong host to lose its 266 * lock state if cookies were not unique across reboots. 267 * 268 * The cookies are exposed only to local user space via loopback. They 269 * do not appear on the physical network. If we want greater security 270 * for some reason, nsm_init_private() could perform a one-way hash to 271 * obscure the contents of the cookie. 272 */ 273 static void nsm_init_private(struct nsm_handle *nsm) 274 { 275 u64 *p = (u64 *)&nsm->sm_priv.data; 276 struct timespec ts; 277 278 ktime_get_ts(&ts); 279 *p++ = timespec_to_ns(&ts); 280 *p = (unsigned long)nsm; 281 } 282 283 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 284 const size_t salen, 285 const char *hostname, 286 const size_t hostname_len) 287 { 288 struct nsm_handle *new; 289 290 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL); 291 if (unlikely(new == NULL)) 292 return NULL; 293 294 atomic_set(&new->sm_count, 1); 295 new->sm_name = (char *)(new + 1); 296 memcpy(nsm_addr(new), sap, salen); 297 new->sm_addrlen = salen; 298 nsm_init_private(new); 299 nsm_display_address((const struct sockaddr *)&new->sm_addr, 300 new->sm_addrbuf, sizeof(new->sm_addrbuf)); 301 memcpy(new->sm_name, hostname, hostname_len); 302 new->sm_name[hostname_len] = '\0'; 303 304 return new; 305 } 306 307 /** 308 * nsm_get_handle - Find or create a cached nsm_handle 309 * @sap: pointer to socket address of handle to find 310 * @salen: length of socket address 311 * @hostname: pointer to C string containing hostname to find 312 * @hostname_len: length of C string 313 * 314 * Behavior is modulated by the global nsm_use_hostnames variable. 315 * 316 * Returns a cached nsm_handle after bumping its ref count, or 317 * returns a fresh nsm_handle if a handle that matches @sap and/or 318 * @hostname cannot be found in the handle cache. Returns NULL if 319 * an error occurs. 320 */ 321 struct nsm_handle *nsm_get_handle(const struct sockaddr *sap, 322 const size_t salen, const char *hostname, 323 const size_t hostname_len) 324 { 325 struct nsm_handle *cached, *new = NULL; 326 327 if (hostname && memchr(hostname, '/', hostname_len) != NULL) { 328 if (printk_ratelimit()) { 329 printk(KERN_WARNING "Invalid hostname \"%.*s\" " 330 "in NFS lock request\n", 331 (int)hostname_len, hostname); 332 } 333 return NULL; 334 } 335 336 retry: 337 spin_lock(&nsm_lock); 338 339 if (nsm_use_hostnames && hostname != NULL) 340 cached = nsm_lookup_hostname(hostname, hostname_len); 341 else 342 cached = nsm_lookup_addr(sap); 343 344 if (cached != NULL) { 345 atomic_inc(&cached->sm_count); 346 spin_unlock(&nsm_lock); 347 kfree(new); 348 dprintk("lockd: found nsm_handle for %s (%s), " 349 "cnt %d\n", cached->sm_name, 350 cached->sm_addrbuf, 351 atomic_read(&cached->sm_count)); 352 return cached; 353 } 354 355 if (new != NULL) { 356 list_add(&new->sm_link, &nsm_handles); 357 spin_unlock(&nsm_lock); 358 dprintk("lockd: created nsm_handle for %s (%s)\n", 359 new->sm_name, new->sm_addrbuf); 360 return new; 361 } 362 363 spin_unlock(&nsm_lock); 364 365 new = nsm_create_handle(sap, salen, hostname, hostname_len); 366 if (unlikely(new == NULL)) 367 return NULL; 368 goto retry; 369 } 370 371 /** 372 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle 373 * @info: pointer to NLMPROC_SM_NOTIFY arguments 374 * 375 * Returns a matching nsm_handle if found in the nsm cache; the returned 376 * nsm_handle's reference count is bumped and sm_monitored is cleared. 377 * Otherwise returns NULL if some error occurred. 378 */ 379 struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info) 380 { 381 struct nsm_handle *cached; 382 383 spin_lock(&nsm_lock); 384 385 cached = nsm_lookup_priv(&info->priv); 386 if (unlikely(cached == NULL)) { 387 spin_unlock(&nsm_lock); 388 dprintk("lockd: never saw rebooted peer '%.*s' before\n", 389 info->len, info->mon); 390 return cached; 391 } 392 393 atomic_inc(&cached->sm_count); 394 spin_unlock(&nsm_lock); 395 396 /* 397 * During subsequent lock activity, force a fresh 398 * notification to be set up for this host. 399 */ 400 cached->sm_monitored = 0; 401 402 dprintk("lockd: host %s (%s) rebooted, cnt %d\n", 403 cached->sm_name, cached->sm_addrbuf, 404 atomic_read(&cached->sm_count)); 405 return cached; 406 } 407 408 /** 409 * nsm_release - Release an NSM handle 410 * @nsm: pointer to handle to be released 411 * 412 */ 413 void nsm_release(struct nsm_handle *nsm) 414 { 415 if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) { 416 list_del(&nsm->sm_link); 417 spin_unlock(&nsm_lock); 418 dprintk("lockd: destroyed nsm_handle for %s (%s)\n", 419 nsm->sm_name, nsm->sm_addrbuf); 420 kfree(nsm); 421 } 422 } 423 424 /* 425 * XDR functions for NSM. 426 * 427 * See http://www.opengroup.org/ for details on the Network 428 * Status Monitor wire protocol. 429 */ 430 431 static int encode_nsm_string(struct xdr_stream *xdr, const char *string) 432 { 433 const u32 len = strlen(string); 434 __be32 *p; 435 436 if (unlikely(len > SM_MAXSTRLEN)) 437 return -EIO; 438 p = xdr_reserve_space(xdr, sizeof(u32) + len); 439 if (unlikely(p == NULL)) 440 return -EIO; 441 xdr_encode_opaque(p, string, len); 442 return 0; 443 } 444 445 /* 446 * "mon_name" specifies the host to be monitored. 447 */ 448 static int encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp) 449 { 450 return encode_nsm_string(xdr, argp->mon_name); 451 } 452 453 /* 454 * The "my_id" argument specifies the hostname and RPC procedure 455 * to be called when the status manager receives notification 456 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" 457 * has changed. 458 */ 459 static int encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp) 460 { 461 int status; 462 __be32 *p; 463 464 status = encode_nsm_string(xdr, utsname()->nodename); 465 if (unlikely(status != 0)) 466 return status; 467 p = xdr_reserve_space(xdr, 3 * sizeof(u32)); 468 if (unlikely(p == NULL)) 469 return -EIO; 470 *p++ = htonl(argp->prog); 471 *p++ = htonl(argp->vers); 472 *p++ = htonl(argp->proc); 473 return 0; 474 } 475 476 /* 477 * The "mon_id" argument specifies the non-private arguments 478 * of an NSMPROC_MON or NSMPROC_UNMON call. 479 */ 480 static int encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp) 481 { 482 int status; 483 484 status = encode_mon_name(xdr, argp); 485 if (unlikely(status != 0)) 486 return status; 487 return encode_my_id(xdr, argp); 488 } 489 490 /* 491 * The "priv" argument may contain private information required 492 * by the NSMPROC_MON call. This information will be supplied in the 493 * NLMPROC_SM_NOTIFY call. 494 */ 495 static int encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp) 496 { 497 __be32 *p; 498 499 p = xdr_reserve_space(xdr, SM_PRIV_SIZE); 500 if (unlikely(p == NULL)) 501 return -EIO; 502 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE); 503 return 0; 504 } 505 506 static int xdr_enc_mon(struct rpc_rqst *req, __be32 *p, 507 const struct nsm_args *argp) 508 { 509 struct xdr_stream xdr; 510 int status; 511 512 xdr_init_encode(&xdr, &req->rq_snd_buf, p); 513 status = encode_mon_id(&xdr, argp); 514 if (unlikely(status)) 515 return status; 516 return encode_priv(&xdr, argp); 517 } 518 519 static int xdr_enc_unmon(struct rpc_rqst *req, __be32 *p, 520 const struct nsm_args *argp) 521 { 522 struct xdr_stream xdr; 523 524 xdr_init_encode(&xdr, &req->rq_snd_buf, p); 525 return encode_mon_id(&xdr, argp); 526 } 527 528 static int xdr_dec_stat_res(struct rpc_rqst *rqstp, __be32 *p, 529 struct nsm_res *resp) 530 { 531 struct xdr_stream xdr; 532 533 xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p); 534 p = xdr_inline_decode(&xdr, 2 * sizeof(u32)); 535 if (unlikely(p == NULL)) 536 return -EIO; 537 resp->status = ntohl(*p++); 538 resp->state = ntohl(*p); 539 540 dprintk("lockd: xdr_dec_stat_res status %d state %d\n", 541 resp->status, resp->state); 542 return 0; 543 } 544 545 static int xdr_dec_stat(struct rpc_rqst *rqstp, __be32 *p, 546 struct nsm_res *resp) 547 { 548 struct xdr_stream xdr; 549 550 xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p); 551 p = xdr_inline_decode(&xdr, sizeof(u32)); 552 if (unlikely(p == NULL)) 553 return -EIO; 554 resp->state = ntohl(*p); 555 556 dprintk("lockd: xdr_dec_stat state %d\n", resp->state); 557 return 0; 558 } 559 560 #define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 561 #define SM_my_id_sz (SM_my_name_sz+3) 562 #define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 563 #define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz) 564 #define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE)) 565 #define SM_mon_sz (SM_mon_id_sz+SM_priv_sz) 566 #define SM_monres_sz 2 567 #define SM_unmonres_sz 1 568 569 static struct rpc_procinfo nsm_procedures[] = { 570 [NSMPROC_MON] = { 571 .p_proc = NSMPROC_MON, 572 .p_encode = (kxdrproc_t)xdr_enc_mon, 573 .p_decode = (kxdrproc_t)xdr_dec_stat_res, 574 .p_arglen = SM_mon_sz, 575 .p_replen = SM_monres_sz, 576 .p_statidx = NSMPROC_MON, 577 .p_name = "MONITOR", 578 }, 579 [NSMPROC_UNMON] = { 580 .p_proc = NSMPROC_UNMON, 581 .p_encode = (kxdrproc_t)xdr_enc_unmon, 582 .p_decode = (kxdrproc_t)xdr_dec_stat, 583 .p_arglen = SM_mon_id_sz, 584 .p_replen = SM_unmonres_sz, 585 .p_statidx = NSMPROC_UNMON, 586 .p_name = "UNMONITOR", 587 }, 588 }; 589 590 static struct rpc_version nsm_version1 = { 591 .number = 1, 592 .nrprocs = ARRAY_SIZE(nsm_procedures), 593 .procs = nsm_procedures 594 }; 595 596 static struct rpc_version * nsm_version[] = { 597 [1] = &nsm_version1, 598 }; 599 600 static struct rpc_stat nsm_stats; 601 602 static struct rpc_program nsm_program = { 603 .name = "statd", 604 .number = NSM_PROGRAM, 605 .nrvers = ARRAY_SIZE(nsm_version), 606 .version = nsm_version, 607 .stats = &nsm_stats 608 }; 609