linux/fs/lockd/mon.c
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   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/xprtsock.h>
  16#include <linux/sunrpc/svc.h>
  17#include <linux/lockd/lockd.h>
  18
  19#include <asm/unaligned.h>
  20
  21#include "netns.h"
  22
  23#define NLMDBG_FACILITY         NLMDBG_MONITOR
  24#define NSM_PROGRAM             100024
  25#define NSM_VERSION             1
  26
  27enum {
  28        NSMPROC_NULL,
  29        NSMPROC_STAT,
  30        NSMPROC_MON,
  31        NSMPROC_UNMON,
  32        NSMPROC_UNMON_ALL,
  33        NSMPROC_SIMU_CRASH,
  34        NSMPROC_NOTIFY,
  35};
  36
  37struct nsm_args {
  38        struct nsm_private      *priv;
  39        u32                     prog;           /* RPC callback info */
  40        u32                     vers;
  41        u32                     proc;
  42
  43        char                    *mon_name;
  44        char                    *nodename;
  45};
  46
  47struct nsm_res {
  48        u32                     status;
  49        u32                     state;
  50};
  51
  52static const struct rpc_program nsm_program;
  53static                          LIST_HEAD(nsm_handles);
  54static                          DEFINE_SPINLOCK(nsm_lock);
  55
  56/*
  57 * Local NSM state
  58 */
  59u32     __read_mostly           nsm_local_state;
  60bool    __read_mostly           nsm_use_hostnames;
  61
  62static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm)
  63{
  64        return (struct sockaddr *)&nsm->sm_addr;
  65}
  66
  67static struct rpc_clnt *nsm_create(struct net *net)
  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                .program                = &nsm_program,
  80                .version                = NSM_VERSION,
  81                .authflavor             = RPC_AUTH_NULL,
  82                .flags                  = RPC_CLNT_CREATE_NOPING,
  83        };
  84
  85        return rpc_create(&args);
  86}
  87
  88static struct rpc_clnt *nsm_client_set(struct lockd_net *ln,
  89                struct rpc_clnt *clnt)
  90{
  91        spin_lock(&ln->nsm_clnt_lock);
  92        if (ln->nsm_users == 0) {
  93                if (clnt == NULL)
  94                        goto out;
  95                ln->nsm_clnt = clnt;
  96        }
  97        clnt = ln->nsm_clnt;
  98        ln->nsm_users++;
  99out:
 100        spin_unlock(&ln->nsm_clnt_lock);
 101        return clnt;
 102}
 103
 104static struct rpc_clnt *nsm_client_get(struct net *net)
 105{
 106        struct rpc_clnt *clnt, *new;
 107        struct lockd_net *ln = net_generic(net, lockd_net_id);
 108
 109        clnt = nsm_client_set(ln, NULL);
 110        if (clnt != NULL)
 111                goto out;
 112
 113        clnt = new = nsm_create(net);
 114        if (IS_ERR(clnt))
 115                goto out;
 116
 117        clnt = nsm_client_set(ln, new);
 118        if (clnt != new)
 119                rpc_shutdown_client(new);
 120out:
 121        return clnt;
 122}
 123
 124static void nsm_client_put(struct net *net)
 125{
 126        struct lockd_net *ln = net_generic(net, lockd_net_id);
 127        struct rpc_clnt *clnt = NULL;
 128
 129        spin_lock(&ln->nsm_clnt_lock);
 130        ln->nsm_users--;
 131        if (ln->nsm_users == 0) {
 132                clnt = ln->nsm_clnt;
 133                ln->nsm_clnt = NULL;
 134        }
 135        spin_unlock(&ln->nsm_clnt_lock);
 136        if (clnt != NULL)
 137                rpc_shutdown_client(clnt);
 138}
 139
 140static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res,
 141                         struct rpc_clnt *clnt)
 142{
 143        int             status;
 144        struct nsm_args args = {
 145                .priv           = &nsm->sm_priv,
 146                .prog           = NLM_PROGRAM,
 147                .vers           = 3,
 148                .proc           = NLMPROC_NSM_NOTIFY,
 149                .mon_name       = nsm->sm_mon_name,
 150                .nodename       = clnt->cl_nodename,
 151        };
 152        struct rpc_message msg = {
 153                .rpc_argp       = &args,
 154                .rpc_resp       = res,
 155        };
 156
 157        BUG_ON(clnt == NULL);
 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 < 0)
 164                dprintk("lockd: NSM upcall RPC failed, status=%d\n",
 165                                status);
 166        else
 167                status = 0;
 168        return status;
 169}
 170
 171/**
 172 * nsm_monitor - Notify a peer in case we reboot
 173 * @host: pointer to nlm_host of peer to notify
 174 *
 175 * If this peer is not already monitored, this function sends an
 176 * upcall to the local rpc.statd to record the name/address of
 177 * the peer to notify in case we reboot.
 178 *
 179 * Returns zero if the peer is monitored by the local rpc.statd;
 180 * otherwise a negative errno value is returned.
 181 */
 182int nsm_monitor(const struct nlm_host *host)
 183{
 184        struct nsm_handle *nsm = host->h_nsmhandle;
 185        struct nsm_res  res;
 186        int             status;
 187        struct rpc_clnt *clnt;
 188
 189        dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name);
 190
 191        if (nsm->sm_monitored)
 192                return 0;
 193
 194        /*
 195         * Choose whether to record the caller_name or IP address of
 196         * this peer in the local rpc.statd's database.
 197         */
 198        nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf;
 199
 200        clnt = nsm_client_get(host->net);
 201        if (IS_ERR(clnt)) {
 202                status = PTR_ERR(clnt);
 203                dprintk("lockd: failed to create NSM upcall transport, "
 204                                "status=%d, net=%p\n", status, host->net);
 205                return status;
 206        }
 207
 208        status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, clnt);
 209        if (unlikely(res.status != 0))
 210                status = -EIO;
 211        if (unlikely(status < 0)) {
 212                printk(KERN_NOTICE "lockd: cannot monitor %s\n", nsm->sm_name);
 213                return status;
 214        }
 215
 216        nsm->sm_monitored = 1;
 217        if (unlikely(nsm_local_state != res.state)) {
 218                nsm_local_state = res.state;
 219                dprintk("lockd: NSM state changed to %d\n", nsm_local_state);
 220        }
 221        return 0;
 222}
 223
 224/**
 225 * nsm_unmonitor - Unregister peer notification
 226 * @host: pointer to nlm_host of peer to stop monitoring
 227 *
 228 * If this peer is monitored, this function sends an upcall to
 229 * tell the local rpc.statd not to send this peer a notification
 230 * when we reboot.
 231 */
 232void nsm_unmonitor(const struct nlm_host *host)
 233{
 234        struct nsm_handle *nsm = host->h_nsmhandle;
 235        struct nsm_res  res;
 236        int status;
 237
 238        if (atomic_read(&nsm->sm_count) == 1
 239         && nsm->sm_monitored && !nsm->sm_sticky) {
 240                struct lockd_net *ln = net_generic(host->net, lockd_net_id);
 241
 242                dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name);
 243
 244                status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, ln->nsm_clnt);
 245                if (res.status != 0)
 246                        status = -EIO;
 247                if (status < 0)
 248                        printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",
 249                                        nsm->sm_name);
 250                else
 251                        nsm->sm_monitored = 0;
 252
 253                nsm_client_put(host->net);
 254        }
 255}
 256
 257static struct nsm_handle *nsm_lookup_hostname(const char *hostname,
 258                                              const size_t len)
 259{
 260        struct nsm_handle *nsm;
 261
 262        list_for_each_entry(nsm, &nsm_handles, sm_link)
 263                if (strlen(nsm->sm_name) == len &&
 264                    memcmp(nsm->sm_name, hostname, len) == 0)
 265                        return nsm;
 266        return NULL;
 267}
 268
 269static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap)
 270{
 271        struct nsm_handle *nsm;
 272
 273        list_for_each_entry(nsm, &nsm_handles, sm_link)
 274                if (rpc_cmp_addr(nsm_addr(nsm), sap))
 275                        return nsm;
 276        return NULL;
 277}
 278
 279static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv)
 280{
 281        struct nsm_handle *nsm;
 282
 283        list_for_each_entry(nsm, &nsm_handles, sm_link)
 284                if (memcmp(nsm->sm_priv.data, priv->data,
 285                                        sizeof(priv->data)) == 0)
 286                        return nsm;
 287        return NULL;
 288}
 289
 290/*
 291 * Construct a unique cookie to match this nsm_handle to this monitored
 292 * host.  It is passed to the local rpc.statd via NSMPROC_MON, and
 293 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these
 294 * requests.
 295 *
 296 * The NSM protocol requires that these cookies be unique while the
 297 * system is running.  We prefer a stronger requirement of making them
 298 * unique across reboots.  If user space bugs cause a stale cookie to
 299 * be sent to the kernel, it could cause the wrong host to lose its
 300 * lock state if cookies were not unique across reboots.
 301 *
 302 * The cookies are exposed only to local user space via loopback.  They
 303 * do not appear on the physical network.  If we want greater security
 304 * for some reason, nsm_init_private() could perform a one-way hash to
 305 * obscure the contents of the cookie.
 306 */
 307static void nsm_init_private(struct nsm_handle *nsm)
 308{
 309        u64 *p = (u64 *)&nsm->sm_priv.data;
 310        struct timespec ts;
 311        s64 ns;
 312
 313        ktime_get_ts(&ts);
 314        ns = timespec_to_ns(&ts);
 315        put_unaligned(ns, p);
 316        put_unaligned((unsigned long)nsm, p + 1);
 317}
 318
 319static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
 320                                            const size_t salen,
 321                                            const char *hostname,
 322                                            const size_t hostname_len)
 323{
 324        struct nsm_handle *new;
 325
 326        new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL);
 327        if (unlikely(new == NULL))
 328                return NULL;
 329
 330        atomic_set(&new->sm_count, 1);
 331        new->sm_name = (char *)(new + 1);
 332        memcpy(nsm_addr(new), sap, salen);
 333        new->sm_addrlen = salen;
 334        nsm_init_private(new);
 335
 336        if (rpc_ntop(nsm_addr(new), new->sm_addrbuf,
 337                                        sizeof(new->sm_addrbuf)) == 0)
 338                (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf),
 339                                "unsupported address family");
 340        memcpy(new->sm_name, hostname, hostname_len);
 341        new->sm_name[hostname_len] = '\0';
 342
 343        return new;
 344}
 345
 346/**
 347 * nsm_get_handle - Find or create a cached nsm_handle
 348 * @sap: pointer to socket address of handle to find
 349 * @salen: length of socket address
 350 * @hostname: pointer to C string containing hostname to find
 351 * @hostname_len: length of C string
 352 *
 353 * Behavior is modulated by the global nsm_use_hostnames variable.
 354 *
 355 * Returns a cached nsm_handle after bumping its ref count, or
 356 * returns a fresh nsm_handle if a handle that matches @sap and/or
 357 * @hostname cannot be found in the handle cache.  Returns NULL if
 358 * an error occurs.
 359 */
 360struct nsm_handle *nsm_get_handle(const struct sockaddr *sap,
 361                                  const size_t salen, const char *hostname,
 362                                  const size_t hostname_len)
 363{
 364        struct nsm_handle *cached, *new = NULL;
 365
 366        if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
 367                if (printk_ratelimit()) {
 368                        printk(KERN_WARNING "Invalid hostname \"%.*s\" "
 369                                            "in NFS lock request\n",
 370                                (int)hostname_len, hostname);
 371                }
 372                return NULL;
 373        }
 374
 375retry:
 376        spin_lock(&nsm_lock);
 377
 378        if (nsm_use_hostnames && hostname != NULL)
 379                cached = nsm_lookup_hostname(hostname, hostname_len);
 380        else
 381                cached = nsm_lookup_addr(sap);
 382
 383        if (cached != NULL) {
 384                atomic_inc(&cached->sm_count);
 385                spin_unlock(&nsm_lock);
 386                kfree(new);
 387                dprintk("lockd: found nsm_handle for %s (%s), "
 388                                "cnt %d\n", cached->sm_name,
 389                                cached->sm_addrbuf,
 390                                atomic_read(&cached->sm_count));
 391                return cached;
 392        }
 393
 394        if (new != NULL) {
 395                list_add(&new->sm_link, &nsm_handles);
 396                spin_unlock(&nsm_lock);
 397                dprintk("lockd: created nsm_handle for %s (%s)\n",
 398                                new->sm_name, new->sm_addrbuf);
 399                return new;
 400        }
 401
 402        spin_unlock(&nsm_lock);
 403
 404        new = nsm_create_handle(sap, salen, hostname, hostname_len);
 405        if (unlikely(new == NULL))
 406                return NULL;
 407        goto retry;
 408}
 409
 410/**
 411 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle
 412 * @info: pointer to NLMPROC_SM_NOTIFY arguments
 413 *
 414 * Returns a matching nsm_handle if found in the nsm cache. The returned
 415 * nsm_handle's reference count is bumped. Otherwise returns NULL if some
 416 * error occurred.
 417 */
 418struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info)
 419{
 420        struct nsm_handle *cached;
 421
 422        spin_lock(&nsm_lock);
 423
 424        cached = nsm_lookup_priv(&info->priv);
 425        if (unlikely(cached == NULL)) {
 426                spin_unlock(&nsm_lock);
 427                dprintk("lockd: never saw rebooted peer '%.*s' before\n",
 428                                info->len, info->mon);
 429                return cached;
 430        }
 431
 432        atomic_inc(&cached->sm_count);
 433        spin_unlock(&nsm_lock);
 434
 435        dprintk("lockd: host %s (%s) rebooted, cnt %d\n",
 436                        cached->sm_name, cached->sm_addrbuf,
 437                        atomic_read(&cached->sm_count));
 438        return cached;
 439}
 440
 441/**
 442 * nsm_release - Release an NSM handle
 443 * @nsm: pointer to handle to be released
 444 *
 445 */
 446void nsm_release(struct nsm_handle *nsm)
 447{
 448        if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
 449                list_del(&nsm->sm_link);
 450                spin_unlock(&nsm_lock);
 451                dprintk("lockd: destroyed nsm_handle for %s (%s)\n",
 452                                nsm->sm_name, nsm->sm_addrbuf);
 453                kfree(nsm);
 454        }
 455}
 456
 457/*
 458 * XDR functions for NSM.
 459 *
 460 * See http://www.opengroup.org/ for details on the Network
 461 * Status Monitor wire protocol.
 462 */
 463
 464static void encode_nsm_string(struct xdr_stream *xdr, const char *string)
 465{
 466        const u32 len = strlen(string);
 467        __be32 *p;
 468
 469        BUG_ON(len > SM_MAXSTRLEN);
 470        p = xdr_reserve_space(xdr, 4 + len);
 471        xdr_encode_opaque(p, string, len);
 472}
 473
 474/*
 475 * "mon_name" specifies the host to be monitored.
 476 */
 477static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp)
 478{
 479        encode_nsm_string(xdr, argp->mon_name);
 480}
 481
 482/*
 483 * The "my_id" argument specifies the hostname and RPC procedure
 484 * to be called when the status manager receives notification
 485 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name"
 486 * has changed.
 487 */
 488static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
 489{
 490        __be32 *p;
 491
 492        encode_nsm_string(xdr, argp->nodename);
 493        p = xdr_reserve_space(xdr, 4 + 4 + 4);
 494        *p++ = cpu_to_be32(argp->prog);
 495        *p++ = cpu_to_be32(argp->vers);
 496        *p = cpu_to_be32(argp->proc);
 497}
 498
 499/*
 500 * The "mon_id" argument specifies the non-private arguments
 501 * of an NSMPROC_MON or NSMPROC_UNMON call.
 502 */
 503static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp)
 504{
 505        encode_mon_name(xdr, argp);
 506        encode_my_id(xdr, argp);
 507}
 508
 509/*
 510 * The "priv" argument may contain private information required
 511 * by the NSMPROC_MON call. This information will be supplied in the
 512 * NLMPROC_SM_NOTIFY call.
 513 */
 514static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp)
 515{
 516        __be32 *p;
 517
 518        p = xdr_reserve_space(xdr, SM_PRIV_SIZE);
 519        xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE);
 520}
 521
 522static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr,
 523                            const struct nsm_args *argp)
 524{
 525        encode_mon_id(xdr, argp);
 526        encode_priv(xdr, argp);
 527}
 528
 529static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr,
 530                              const struct nsm_args *argp)
 531{
 532        encode_mon_id(xdr, argp);
 533}
 534
 535static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp,
 536                                struct xdr_stream *xdr,
 537                                struct nsm_res *resp)
 538{
 539        __be32 *p;
 540
 541        p = xdr_inline_decode(xdr, 4 + 4);
 542        if (unlikely(p == NULL))
 543                return -EIO;
 544        resp->status = be32_to_cpup(p++);
 545        resp->state = be32_to_cpup(p);
 546
 547        dprintk("lockd: %s status %d state %d\n",
 548                __func__, resp->status, resp->state);
 549        return 0;
 550}
 551
 552static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp,
 553                            struct xdr_stream *xdr,
 554                            struct nsm_res *resp)
 555{
 556        __be32 *p;
 557
 558        p = xdr_inline_decode(xdr, 4);
 559        if (unlikely(p == NULL))
 560                return -EIO;
 561        resp->state = be32_to_cpup(p);
 562
 563        dprintk("lockd: %s state %d\n", __func__, resp->state);
 564        return 0;
 565}
 566
 567#define SM_my_name_sz   (1+XDR_QUADLEN(SM_MAXSTRLEN))
 568#define SM_my_id_sz     (SM_my_name_sz+3)
 569#define SM_mon_name_sz  (1+XDR_QUADLEN(SM_MAXSTRLEN))
 570#define SM_mon_id_sz    (SM_mon_name_sz+SM_my_id_sz)
 571#define SM_priv_sz      (XDR_QUADLEN(SM_PRIV_SIZE))
 572#define SM_mon_sz       (SM_mon_id_sz+SM_priv_sz)
 573#define SM_monres_sz    2
 574#define SM_unmonres_sz  1
 575
 576static struct rpc_procinfo      nsm_procedures[] = {
 577[NSMPROC_MON] = {
 578                .p_proc         = NSMPROC_MON,
 579                .p_encode       = (kxdreproc_t)nsm_xdr_enc_mon,
 580                .p_decode       = (kxdrdproc_t)nsm_xdr_dec_stat_res,
 581                .p_arglen       = SM_mon_sz,
 582                .p_replen       = SM_monres_sz,
 583                .p_statidx      = NSMPROC_MON,
 584                .p_name         = "MONITOR",
 585        },
 586[NSMPROC_UNMON] = {
 587                .p_proc         = NSMPROC_UNMON,
 588                .p_encode       = (kxdreproc_t)nsm_xdr_enc_unmon,
 589                .p_decode       = (kxdrdproc_t)nsm_xdr_dec_stat,
 590                .p_arglen       = SM_mon_id_sz,
 591                .p_replen       = SM_unmonres_sz,
 592                .p_statidx      = NSMPROC_UNMON,
 593                .p_name         = "UNMONITOR",
 594        },
 595};
 596
 597static const struct rpc_version nsm_version1 = {
 598                .number         = 1,
 599                .nrprocs        = ARRAY_SIZE(nsm_procedures),
 600                .procs          = nsm_procedures
 601};
 602
 603static const struct rpc_version *nsm_version[] = {
 604        [1] = &nsm_version1,
 605};
 606
 607static struct rpc_stat          nsm_stats;
 608
 609static const struct rpc_program nsm_program = {
 610                .name           = "statd",
 611                .number         = NSM_PROGRAM,
 612                .nrvers         = ARRAY_SIZE(nsm_version),
 613                .version        = nsm_version,
 614                .stats          = &nsm_stats
 615};
 616
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