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 const 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 DEFINE_SPINLOCK(nsm_lock); 55 56 /* 57 * Local NSM state 58 */ 59 u32 __read_mostly nsm_local_state; 60 bool __read_mostly nsm_use_hostnames; 61 62 static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm) 63 { 64 return (struct sockaddr *)&nsm->sm_addr; 65 } 66 67 static struct rpc_clnt *nsm_create(struct net *net, const char *nodename) 68 { 69 struct sockaddr_in sin = { 70 .sin_family = AF_INET, 71 .sin_addr.s_addr = htonl(INADDR_LOOPBACK), 72 }; 73 struct rpc_create_args args = { 74 .net = net, 75 .protocol = XPRT_TRANSPORT_TCP, 76 .address = (struct sockaddr *)&sin, 77 .addrsize = sizeof(sin), 78 .servername = "rpc.statd", 79 .nodename = nodename, 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 int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res, 90 const struct nlm_host *host) 91 { 92 int status; 93 struct rpc_clnt *clnt; 94 struct nsm_args args = { 95 .priv = &nsm->sm_priv, 96 .prog = NLM_PROGRAM, 97 .vers = 3, 98 .proc = NLMPROC_NSM_NOTIFY, 99 .mon_name = nsm->sm_mon_name, 100 .nodename = host->nodename, 101 }; 102 struct rpc_message msg = { 103 .rpc_argp = &args, 104 .rpc_resp = res, 105 }; 106 107 memset(res, 0, sizeof(*res)); 108 109 clnt = nsm_create(host->net, host->nodename); 110 if (IS_ERR(clnt)) { 111 dprintk("lockd: failed to create NSM upcall transport, " 112 "status=%ld, net=%p\n", PTR_ERR(clnt), host->net); 113 return PTR_ERR(clnt); 114 } 115 116 msg.rpc_proc = &clnt->cl_procinfo[proc]; 117 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN); 118 if (status == -ECONNREFUSED) { 119 dprintk("lockd: NSM upcall RPC failed, status=%d, forcing rebind\n", 120 status); 121 rpc_force_rebind(clnt); 122 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN); 123 } 124 if (status < 0) 125 dprintk("lockd: NSM upcall RPC failed, status=%d\n", 126 status); 127 else 128 status = 0; 129 130 rpc_shutdown_client(clnt); 131 return status; 132 } 133 134 /** 135 * nsm_monitor - Notify a peer in case we reboot 136 * @host: pointer to nlm_host of peer to notify 137 * 138 * If this peer is not already monitored, this function sends an 139 * upcall to the local rpc.statd to record the name/address of 140 * the peer to notify in case we reboot. 141 * 142 * Returns zero if the peer is monitored by the local rpc.statd; 143 * otherwise a negative errno value is returned. 144 */ 145 int nsm_monitor(const struct nlm_host *host) 146 { 147 struct nsm_handle *nsm = host->h_nsmhandle; 148 struct nsm_res res; 149 int status; 150 151 dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name); 152 153 if (nsm->sm_monitored) 154 return 0; 155 156 /* 157 * Choose whether to record the caller_name or IP address of 158 * this peer in the local rpc.statd's database. 159 */ 160 nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf; 161 162 status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, host); 163 if (unlikely(res.status != 0)) 164 status = -EIO; 165 if (unlikely(status < 0)) { 166 pr_notice_ratelimited("lockd: cannot monitor %s\n", nsm->sm_name); 167 return status; 168 } 169 170 nsm->sm_monitored = 1; 171 if (unlikely(nsm_local_state != res.state)) { 172 nsm_local_state = res.state; 173 dprintk("lockd: NSM state changed to %d\n", nsm_local_state); 174 } 175 return 0; 176 } 177 178 /** 179 * nsm_unmonitor - Unregister peer notification 180 * @host: pointer to nlm_host of peer to stop monitoring 181 * 182 * If this peer is monitored, this function sends an upcall to 183 * tell the local rpc.statd not to send this peer a notification 184 * when we reboot. 185 */ 186 void nsm_unmonitor(const struct nlm_host *host) 187 { 188 struct nsm_handle *nsm = host->h_nsmhandle; 189 struct nsm_res res; 190 int status; 191 192 if (atomic_read(&nsm->sm_count) == 1 193 && nsm->sm_monitored && !nsm->sm_sticky) { 194 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name); 195 196 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, host); 197 if (res.status != 0) 198 status = -EIO; 199 if (status < 0) 200 printk(KERN_NOTICE "lockd: cannot unmonitor %s\n", 201 nsm->sm_name); 202 else 203 nsm->sm_monitored = 0; 204 } 205 } 206 207 static struct nsm_handle *nsm_lookup_hostname(const struct list_head *nsm_handles, 208 const char *hostname, const size_t len) 209 { 210 struct nsm_handle *nsm; 211 212 list_for_each_entry(nsm, nsm_handles, sm_link) 213 if (strlen(nsm->sm_name) == len && 214 memcmp(nsm->sm_name, hostname, len) == 0) 215 return nsm; 216 return NULL; 217 } 218 219 static struct nsm_handle *nsm_lookup_addr(const struct list_head *nsm_handles, 220 const struct sockaddr *sap) 221 { 222 struct nsm_handle *nsm; 223 224 list_for_each_entry(nsm, nsm_handles, sm_link) 225 if (rpc_cmp_addr(nsm_addr(nsm), sap)) 226 return nsm; 227 return NULL; 228 } 229 230 static struct nsm_handle *nsm_lookup_priv(const struct list_head *nsm_handles, 231 const struct nsm_private *priv) 232 { 233 struct nsm_handle *nsm; 234 235 list_for_each_entry(nsm, nsm_handles, sm_link) 236 if (memcmp(nsm->sm_priv.data, priv->data, 237 sizeof(priv->data)) == 0) 238 return nsm; 239 return NULL; 240 } 241 242 /* 243 * Construct a unique cookie to match this nsm_handle to this monitored 244 * host. It is passed to the local rpc.statd via NSMPROC_MON, and 245 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these 246 * requests. 247 * 248 * The NSM protocol requires that these cookies be unique while the 249 * system is running. We prefer a stronger requirement of making them 250 * unique across reboots. If user space bugs cause a stale cookie to 251 * be sent to the kernel, it could cause the wrong host to lose its 252 * lock state if cookies were not unique across reboots. 253 * 254 * The cookies are exposed only to local user space via loopback. They 255 * do not appear on the physical network. If we want greater security 256 * for some reason, nsm_init_private() could perform a one-way hash to 257 * obscure the contents of the cookie. 258 */ 259 static void nsm_init_private(struct nsm_handle *nsm) 260 { 261 u64 *p = (u64 *)&nsm->sm_priv.data; 262 s64 ns; 263 264 ns = ktime_get_ns(); 265 put_unaligned(ns, p); 266 put_unaligned((unsigned long)nsm, p + 1); 267 } 268 269 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 270 const size_t salen, 271 const char *hostname, 272 const size_t hostname_len) 273 { 274 struct nsm_handle *new; 275 276 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL); 277 if (unlikely(new == NULL)) 278 return NULL; 279 280 atomic_set(&new->sm_count, 1); 281 new->sm_name = (char *)(new + 1); 282 memcpy(nsm_addr(new), sap, salen); 283 new->sm_addrlen = salen; 284 nsm_init_private(new); 285 286 if (rpc_ntop(nsm_addr(new), new->sm_addrbuf, 287 sizeof(new->sm_addrbuf)) == 0) 288 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf), 289 "unsupported address family"); 290 memcpy(new->sm_name, hostname, hostname_len); 291 new->sm_name[hostname_len] = '\0'; 292 293 return new; 294 } 295 296 /** 297 * nsm_get_handle - Find or create a cached nsm_handle 298 * @net: network namespace 299 * @sap: pointer to socket address of handle to find 300 * @salen: length of socket address 301 * @hostname: pointer to C string containing hostname to find 302 * @hostname_len: length of C string 303 * 304 * Behavior is modulated by the global nsm_use_hostnames variable. 305 * 306 * Returns a cached nsm_handle after bumping its ref count, or 307 * returns a fresh nsm_handle if a handle that matches @sap and/or 308 * @hostname cannot be found in the handle cache. Returns NULL if 309 * an error occurs. 310 */ 311 struct nsm_handle *nsm_get_handle(const struct net *net, 312 const struct sockaddr *sap, 313 const size_t salen, const char *hostname, 314 const size_t hostname_len) 315 { 316 struct nsm_handle *cached, *new = NULL; 317 struct lockd_net *ln = net_generic(net, lockd_net_id); 318 319 if (hostname && memchr(hostname, '/', hostname_len) != NULL) { 320 if (printk_ratelimit()) { 321 printk(KERN_WARNING "Invalid hostname \"%.*s\" " 322 "in NFS lock request\n", 323 (int)hostname_len, hostname); 324 } 325 return NULL; 326 } 327 328 retry: 329 spin_lock(&nsm_lock); 330 331 if (nsm_use_hostnames && hostname != NULL) 332 cached = nsm_lookup_hostname(&ln->nsm_handles, 333 hostname, hostname_len); 334 else 335 cached = nsm_lookup_addr(&ln->nsm_handles, sap); 336 337 if (cached != NULL) { 338 atomic_inc(&cached->sm_count); 339 spin_unlock(&nsm_lock); 340 kfree(new); 341 dprintk("lockd: found nsm_handle for %s (%s), " 342 "cnt %d\n", cached->sm_name, 343 cached->sm_addrbuf, 344 atomic_read(&cached->sm_count)); 345 return cached; 346 } 347 348 if (new != NULL) { 349 list_add(&new->sm_link, &ln->nsm_handles); 350 spin_unlock(&nsm_lock); 351 dprintk("lockd: created nsm_handle for %s (%s)\n", 352 new->sm_name, new->sm_addrbuf); 353 return new; 354 } 355 356 spin_unlock(&nsm_lock); 357 358 new = nsm_create_handle(sap, salen, hostname, hostname_len); 359 if (unlikely(new == NULL)) 360 return NULL; 361 goto retry; 362 } 363 364 /** 365 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle 366 * @net: network namespace 367 * @info: pointer to NLMPROC_SM_NOTIFY arguments 368 * 369 * Returns a matching nsm_handle if found in the nsm cache. The returned 370 * nsm_handle's reference count is bumped. Otherwise returns NULL if some 371 * error occurred. 372 */ 373 struct nsm_handle *nsm_reboot_lookup(const struct net *net, 374 const struct nlm_reboot *info) 375 { 376 struct nsm_handle *cached; 377 struct lockd_net *ln = net_generic(net, lockd_net_id); 378 379 spin_lock(&nsm_lock); 380 381 cached = nsm_lookup_priv(&ln->nsm_handles, &info->priv); 382 if (unlikely(cached == NULL)) { 383 spin_unlock(&nsm_lock); 384 dprintk("lockd: never saw rebooted peer '%.*s' before\n", 385 info->len, info->mon); 386 return cached; 387 } 388 389 atomic_inc(&cached->sm_count); 390 spin_unlock(&nsm_lock); 391 392 dprintk("lockd: host %s (%s) rebooted, cnt %d\n", 393 cached->sm_name, cached->sm_addrbuf, 394 atomic_read(&cached->sm_count)); 395 return cached; 396 } 397 398 /** 399 * nsm_release - Release an NSM handle 400 * @nsm: pointer to handle to be released 401 * 402 */ 403 void nsm_release(struct nsm_handle *nsm) 404 { 405 if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) { 406 list_del(&nsm->sm_link); 407 spin_unlock(&nsm_lock); 408 dprintk("lockd: destroyed nsm_handle for %s (%s)\n", 409 nsm->sm_name, nsm->sm_addrbuf); 410 kfree(nsm); 411 } 412 } 413 414 /* 415 * XDR functions for NSM. 416 * 417 * See http://www.opengroup.org/ for details on the Network 418 * Status Monitor wire protocol. 419 */ 420 421 static void encode_nsm_string(struct xdr_stream *xdr, const char *string) 422 { 423 const u32 len = strlen(string); 424 __be32 *p; 425 426 p = xdr_reserve_space(xdr, 4 + len); 427 xdr_encode_opaque(p, string, len); 428 } 429 430 /* 431 * "mon_name" specifies the host to be monitored. 432 */ 433 static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp) 434 { 435 encode_nsm_string(xdr, argp->mon_name); 436 } 437 438 /* 439 * The "my_id" argument specifies the hostname and RPC procedure 440 * to be called when the status manager receives notification 441 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" 442 * has changed. 443 */ 444 static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp) 445 { 446 __be32 *p; 447 448 encode_nsm_string(xdr, argp->nodename); 449 p = xdr_reserve_space(xdr, 4 + 4 + 4); 450 *p++ = cpu_to_be32(argp->prog); 451 *p++ = cpu_to_be32(argp->vers); 452 *p = cpu_to_be32(argp->proc); 453 } 454 455 /* 456 * The "mon_id" argument specifies the non-private arguments 457 * of an NSMPROC_MON or NSMPROC_UNMON call. 458 */ 459 static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp) 460 { 461 encode_mon_name(xdr, argp); 462 encode_my_id(xdr, argp); 463 } 464 465 /* 466 * The "priv" argument may contain private information required 467 * by the NSMPROC_MON call. This information will be supplied in the 468 * NLMPROC_SM_NOTIFY call. 469 */ 470 static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp) 471 { 472 __be32 *p; 473 474 p = xdr_reserve_space(xdr, SM_PRIV_SIZE); 475 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE); 476 } 477 478 static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr, 479 const struct nsm_args *argp) 480 { 481 encode_mon_id(xdr, argp); 482 encode_priv(xdr, argp); 483 } 484 485 static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr, 486 const struct nsm_args *argp) 487 { 488 encode_mon_id(xdr, argp); 489 } 490 491 static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp, 492 struct xdr_stream *xdr, 493 struct nsm_res *resp) 494 { 495 __be32 *p; 496 497 p = xdr_inline_decode(xdr, 4 + 4); 498 if (unlikely(p == NULL)) 499 return -EIO; 500 resp->status = be32_to_cpup(p++); 501 resp->state = be32_to_cpup(p); 502 503 dprintk("lockd: %s status %d state %d\n", 504 __func__, resp->status, resp->state); 505 return 0; 506 } 507 508 static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp, 509 struct xdr_stream *xdr, 510 struct nsm_res *resp) 511 { 512 __be32 *p; 513 514 p = xdr_inline_decode(xdr, 4); 515 if (unlikely(p == NULL)) 516 return -EIO; 517 resp->state = be32_to_cpup(p); 518 519 dprintk("lockd: %s state %d\n", __func__, resp->state); 520 return 0; 521 } 522 523 #define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 524 #define SM_my_id_sz (SM_my_name_sz+3) 525 #define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 526 #define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz) 527 #define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE)) 528 #define SM_mon_sz (SM_mon_id_sz+SM_priv_sz) 529 #define SM_monres_sz 2 530 #define SM_unmonres_sz 1 531 532 static struct rpc_procinfo nsm_procedures[] = { 533 [NSMPROC_MON] = { 534 .p_proc = NSMPROC_MON, 535 .p_encode = (kxdreproc_t)nsm_xdr_enc_mon, 536 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat_res, 537 .p_arglen = SM_mon_sz, 538 .p_replen = SM_monres_sz, 539 .p_statidx = NSMPROC_MON, 540 .p_name = "MONITOR", 541 }, 542 [NSMPROC_UNMON] = { 543 .p_proc = NSMPROC_UNMON, 544 .p_encode = (kxdreproc_t)nsm_xdr_enc_unmon, 545 .p_decode = (kxdrdproc_t)nsm_xdr_dec_stat, 546 .p_arglen = SM_mon_id_sz, 547 .p_replen = SM_unmonres_sz, 548 .p_statidx = NSMPROC_UNMON, 549 .p_name = "UNMONITOR", 550 }, 551 }; 552 553 static const struct rpc_version nsm_version1 = { 554 .number = 1, 555 .nrprocs = ARRAY_SIZE(nsm_procedures), 556 .procs = nsm_procedures 557 }; 558 559 static const struct rpc_version *nsm_version[] = { 560 [1] = &nsm_version1, 561 }; 562 563 static struct rpc_stat nsm_stats; 564 565 static const struct rpc_program nsm_program = { 566 .name = "statd", 567 .number = NSM_PROGRAM, 568 .nrvers = ARRAY_SIZE(nsm_version), 569 .version = nsm_version, 570 .stats = &nsm_stats 571 }; 572