sys/rpc/clnt_rc.c

   1 /*-
   2  * Copyright (c) 2008 Isilon Inc http://www.isilon.com/
   3  * Authors: Doug Rabson <dfr@rabson.org>
   4  * Developed with Red Inc: Alfred Perlstein <alfred@freebsd.org>
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #include <sys/cdefs.h>
  29 __FBSDID("$FreeBSD$");
  30
  31 #include <sys/param.h>
  32 #include <sys/systm.h>
  33 #include <sys/kernel.h>
  34 #include <sys/limits.h>
  35 #include <sys/lock.h>
  36 #include <sys/malloc.h>
  37 #include <sys/mbuf.h>
  38 #include <sys/mutex.h>
  39 #include <sys/pcpu.h>
  40 #include <sys/proc.h>
  41 #include <sys/socket.h>
  42 #include <sys/socketvar.h>
  43 #include <sys/time.h>
  44 #include <sys/uio.h>
  45
  46 #include <rpc/rpc.h>
  47 #include <rpc/rpc_com.h>
  48
  49 static enum clnt_stat clnt_reconnect_call(CLIENT *, struct rpc_callextra *,
  50     rpcproc_t, struct mbuf *, struct mbuf **, struct timeval);
  51 static void clnt_reconnect_geterr(CLIENT *, struct rpc_err *);
  52 static bool_t clnt_reconnect_freeres(CLIENT *, xdrproc_t, void *);
  53 static void clnt_reconnect_abort(CLIENT *);
  54 static bool_t clnt_reconnect_control(CLIENT *, u_int, void *);
  55 static void clnt_reconnect_close(CLIENT *);
  56 static void clnt_reconnect_destroy(CLIENT *);
  57
  58 static struct clnt_ops clnt_reconnect_ops = {
  59         .cl_call =      clnt_reconnect_call,
  60         .cl_abort =     clnt_reconnect_abort,
  61         .cl_geterr =    clnt_reconnect_geterr,
  62         .cl_freeres =   clnt_reconnect_freeres,
  63         .cl_close =     clnt_reconnect_close,
  64         .cl_destroy =   clnt_reconnect_destroy,
  65         .cl_control =   clnt_reconnect_control
  66 };
  67
  68 static int      fake_wchan;
  69
  70 struct rc_data {
  71         struct mtx              rc_lock;
  72         struct sockaddr_storage rc_addr; /* server address */
  73         struct netconfig*       rc_nconf; /* network type */
  74         rpcprog_t               rc_prog;  /* program number */
  75         rpcvers_t               rc_vers;  /* version number */
  76         size_t                  rc_sendsz;
  77         size_t                  rc_recvsz;
  78         struct timeval          rc_timeout;
  79         struct timeval          rc_retry;
  80         int                     rc_retries;
  81         int                     rc_privport;
  82         char                    *rc_waitchan;
  83         int                     rc_intr;
  84         int                     rc_connecting;
  85         int                     rc_closed;
  86         struct ucred            *rc_ucred;
  87         CLIENT*                 rc_client; /* underlying RPC client */
  88         struct rpc_err          rc_err;
  89 };
  90
  91 CLIENT *
  92 clnt_reconnect_create(
  93         struct netconfig *nconf,        /* network type */
  94         struct sockaddr *svcaddr,       /* servers address */
  95         rpcprog_t program,              /* program number */
  96         rpcvers_t version,              /* version number */
  97         size_t sendsz,                  /* buffer recv size */
  98         size_t recvsz)                  /* buffer send size */
  99 {
 100         CLIENT *cl = NULL;              /* client handle */
 101         struct rc_data *rc = NULL;      /* private data */
 102
 103         if (svcaddr == NULL) {
 104                 rpc_createerr.cf_stat = RPC_UNKNOWNADDR;
 105                 return (NULL);
 106         }
 107
 108         cl = mem_alloc(sizeof (CLIENT));
 109         rc = mem_alloc(sizeof (*rc));
 110         mtx_init(&rc->rc_lock, "rc->rc_lock", NULL, MTX_DEF);
 111         (void) memcpy(&rc->rc_addr, svcaddr, (size_t)svcaddr->sa_len);
 112         rc->rc_nconf = nconf;
 113         rc->rc_prog = program;
 114         rc->rc_vers = version;
 115         rc->rc_sendsz = sendsz;
 116         rc->rc_recvsz = recvsz;
 117         rc->rc_timeout.tv_sec = -1;
 118         rc->rc_timeout.tv_usec = -1;
 119         rc->rc_retry.tv_sec = 3;
 120         rc->rc_retry.tv_usec = 0;
 121         rc->rc_retries = INT_MAX;
 122         rc->rc_privport = FALSE;
 123         rc->rc_waitchan = "rpcrecv";
 124         rc->rc_intr = 0;
 125         rc->rc_connecting = FALSE;
 126         rc->rc_closed = FALSE;
 127         rc->rc_ucred = crdup(curthread->td_ucred);
 128         rc->rc_client = NULL;
 129
 130         cl->cl_refs = 1;
 131         cl->cl_ops = &clnt_reconnect_ops;
 132         cl->cl_private = (caddr_t)(void *)rc;
 133         cl->cl_auth = authnone_create();
 134         cl->cl_tp = NULL;
 135         cl->cl_netid = NULL;
 136         return (cl);
 137 }
 138
 139 static enum clnt_stat
 140 clnt_reconnect_connect(CLIENT *cl)
 141 {
 142         struct thread *td = curthread;
 143         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 144         struct socket *so;
 145         enum clnt_stat stat;
 146         int error;
 147         int one = 1;
 148         struct ucred *oldcred;
 149         CLIENT *newclient = NULL;
 150
 151         mtx_lock(&rc->rc_lock);
 152         while (rc->rc_connecting) {
 153                 error = msleep(rc, &rc->rc_lock,
 154                     rc->rc_intr ? PCATCH : 0, "rpcrecon", 0);
 155                 if (error) {
 156                         mtx_unlock(&rc->rc_lock);
 157                         return (RPC_INTR);
 158                 }
 159         }
 160         if (rc->rc_closed) {
 161                 mtx_unlock(&rc->rc_lock);
 162                 return (RPC_CANTSEND);
 163         }
 164         if (rc->rc_client) {
 165                 mtx_unlock(&rc->rc_lock);
 166                 return (RPC_SUCCESS);
 167         }
 168
 169         /*
 170          * My turn to attempt a connect. The rc_connecting variable
 171          * serializes the following code sequence, so it is guaranteed
 172          * that rc_client will still be NULL after it is re-locked below,
 173          * since that is the only place it is set non-NULL.
 174          */
 175         rc->rc_connecting = TRUE;
 176         mtx_unlock(&rc->rc_lock);
 177
 178         so = __rpc_nconf2socket(rc->rc_nconf);
 179         if (!so) {
 180                 stat = rpc_createerr.cf_stat = RPC_TLIERROR;
 181                 rpc_createerr.cf_error.re_errno = 0;
 182                 goto out;
 183         }
 184
 185         oldcred = td->td_ucred;
 186         td->td_ucred = rc->rc_ucred;
 187         if (rc->rc_privport)
 188                 bindresvport(so, NULL);
 189
 190         if (rc->rc_nconf->nc_semantics == NC_TPI_CLTS)
 191                 newclient = clnt_dg_create(so,
 192                     (struct sockaddr *) &rc->rc_addr, rc->rc_prog, rc->rc_vers,
 193                     rc->rc_sendsz, rc->rc_recvsz);
 194         else
 195                 newclient = clnt_vc_create(so,
 196                     (struct sockaddr *) &rc->rc_addr, rc->rc_prog, rc->rc_vers,
 197                     rc->rc_sendsz, rc->rc_recvsz);
 198         td->td_ucred = oldcred;
 199
 200         if (!newclient) {
 201                 soclose(so);
 202                 rc->rc_err = rpc_createerr.cf_error;
 203                 stat = rpc_createerr.cf_stat;
 204                 goto out;
 205         }
 206
 207         CLNT_CONTROL(newclient, CLSET_FD_CLOSE, 0);
 208         CLNT_CONTROL(newclient, CLSET_CONNECT, &one);
 209         CLNT_CONTROL(newclient, CLSET_TIMEOUT, &rc->rc_timeout);
 210         CLNT_CONTROL(newclient, CLSET_RETRY_TIMEOUT, &rc->rc_retry);
 211         CLNT_CONTROL(newclient, CLSET_WAITCHAN, rc->rc_waitchan);
 212         CLNT_CONTROL(newclient, CLSET_INTERRUPTIBLE, &rc->rc_intr);
 213         stat = RPC_SUCCESS;
 214
 215 out:
 216         mtx_lock(&rc->rc_lock);
 217         KASSERT(rc->rc_client == NULL, ("rc_client not null"));
 218         if (!rc->rc_closed) {
 219                 rc->rc_client = newclient;
 220                 newclient = NULL;
 221         }
 222         rc->rc_connecting = FALSE;
 223         wakeup(rc);
 224         mtx_unlock(&rc->rc_lock);
 225
 226         if (newclient) {
 227                 /*
 228                  * It has been closed, so discard the new client.
 229                  * nb: clnt_[dg|vc]_close()/clnt_[dg|vc]_destroy() cannot
 230                  * be called with the rc_lock mutex held, since they may
 231                  * msleep() while holding a different mutex.
 232                  */
 233                 CLNT_CLOSE(newclient);
 234                 CLNT_RELEASE(newclient);
 235         }
 236
 237         return (stat);
 238 }
 239
 240 static enum clnt_stat
 241 clnt_reconnect_call(
 242         CLIENT          *cl,            /* client handle */
 243         struct rpc_callextra *ext,      /* call metadata */
 244         rpcproc_t       proc,           /* procedure number */
 245         struct mbuf     *args,          /* pointer to args */
 246         struct mbuf     **resultsp,     /* pointer to results */
 247         struct timeval  utimeout)
 248 {
 249         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 250         CLIENT *client;
 251         enum clnt_stat stat;
 252         int tries, error;
 253
 254         tries = 0;
 255         do {
 256                 mtx_lock(&rc->rc_lock);
 257                 if (rc->rc_closed) {
 258                         mtx_unlock(&rc->rc_lock);
 259                         return (RPC_CANTSEND);
 260                 }
 261
 262                 if (!rc->rc_client) {
 263                         mtx_unlock(&rc->rc_lock);
 264                         stat = clnt_reconnect_connect(cl);
 265                         if (stat == RPC_SYSTEMERROR) {
 266                                 error = tsleep(&fake_wchan,
 267                                     rc->rc_intr ? PCATCH | PBDRY : 0, "rpccon",
 268                                     hz);
 269                                 if (error == EINTR || error == ERESTART)
 270                                         return (RPC_INTR);
 271                                 tries++;
 272                                 if (tries >= rc->rc_retries)
 273                                         return (stat);
 274                                 continue;
 275                         }
 276                         if (stat != RPC_SUCCESS)
 277                                 return (stat);
 278                         mtx_lock(&rc->rc_lock);
 279                 }
 280
 281                 if (!rc->rc_client) {
 282                         mtx_unlock(&rc->rc_lock);
 283                         stat = RPC_FAILED;
 284                         continue;
 285                 }
 286                 CLNT_ACQUIRE(rc->rc_client);
 287                 client = rc->rc_client;
 288                 mtx_unlock(&rc->rc_lock);
 289                 stat = CLNT_CALL_MBUF(client, ext, proc, args,
 290                     resultsp, utimeout);
 291
 292                 if (stat != RPC_SUCCESS) {
 293                         if (!ext)
 294                                 CLNT_GETERR(client, &rc->rc_err);
 295                 }
 296
 297                 if (stat == RPC_TIMEDOUT) {
 298                         /*
 299                          * Check for async send misfeature for NLM
 300                          * protocol.
 301                          */
 302                         if ((rc->rc_timeout.tv_sec == 0
 303                                 && rc->rc_timeout.tv_usec == 0)
 304                             || (rc->rc_timeout.tv_sec == -1
 305                                 && utimeout.tv_sec == 0
 306                                 && utimeout.tv_usec == 0)) {
 307                                 CLNT_RELEASE(client);
 308                                 break;
 309                         }
 310                 }
 311
 312                 if (stat == RPC_TIMEDOUT || stat == RPC_CANTSEND
 313                     || stat == RPC_CANTRECV) {
 314                         tries++;
 315                         if (tries >= rc->rc_retries) {
 316                                 CLNT_RELEASE(client);
 317                                 break;
 318                         }
 319
 320                         if (ext && ext->rc_feedback)
 321                                 ext->rc_feedback(FEEDBACK_RECONNECT, proc,
 322                                     ext->rc_feedback_arg);
 323
 324                         mtx_lock(&rc->rc_lock);
 325                         /*
 326                          * Make sure that someone else hasn't already
 327                          * reconnected by checking if rc_client has changed.
 328                          * If not, we are done with the client and must
 329                          * do CLNT_RELEASE(client) twice to dispose of it,
 330                          * because there is both an initial refcnt and one
 331                          * acquired by CLNT_ACQUIRE() above.
 332                          */
 333                         if (rc->rc_client == client) {
 334                                 rc->rc_client = NULL;
 335                                 mtx_unlock(&rc->rc_lock);
 336                                 CLNT_RELEASE(client);
 337                         } else {
 338                                 mtx_unlock(&rc->rc_lock);
 339                         }
 340                         CLNT_RELEASE(client);
 341                 } else {
 342                         CLNT_RELEASE(client);
 343                         break;
 344                 }
 345         } while (stat != RPC_SUCCESS);
 346
 347         KASSERT(stat != RPC_SUCCESS || *resultsp,
 348             ("RPC_SUCCESS without reply"));
 349
 350         return (stat);
 351 }
 352
 353 static void
 354 clnt_reconnect_geterr(CLIENT *cl, struct rpc_err *errp)
 355 {
 356         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 357
 358         *errp = rc->rc_err;
 359 }
 360
 361 /*
 362  * Since this function requires that rc_client be valid, it can
 363  * only be called when that is guaranteed to be the case.
 364  */
 365 static bool_t
 366 clnt_reconnect_freeres(CLIENT *cl, xdrproc_t xdr_res, void *res_ptr)
 367 {
 368         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 369
 370         return (CLNT_FREERES(rc->rc_client, xdr_res, res_ptr));
 371 }
 372
 373 /*ARGSUSED*/
 374 static void
 375 clnt_reconnect_abort(CLIENT *h)
 376 {
 377 }
 378
 379 /*
 380  * CLNT_CONTROL() on the client returned by clnt_reconnect_create() must
 381  * always be called before CLNT_CALL_MBUF() by a single thread only.
 382  */
 383 static bool_t
 384 clnt_reconnect_control(CLIENT *cl, u_int request, void *info)
 385 {
 386         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 387
 388         if (info == NULL) {
 389                 return (FALSE);
 390         }
 391         switch (request) {
 392         case CLSET_TIMEOUT:
 393                 rc->rc_timeout = *(struct timeval *)info;
 394                 if (rc->rc_client)
 395                         CLNT_CONTROL(rc->rc_client, request, info);
 396                 break;
 397
 398         case CLGET_TIMEOUT:
 399                 *(struct timeval *)info = rc->rc_timeout;
 400                 break;
 401
 402         case CLSET_RETRY_TIMEOUT:
 403                 rc->rc_retry = *(struct timeval *)info;
 404                 if (rc->rc_client)
 405                         CLNT_CONTROL(rc->rc_client, request, info);
 406                 break;
 407
 408         case CLGET_RETRY_TIMEOUT:
 409                 *(struct timeval *)info = rc->rc_retry;
 410                 break;
 411
 412         case CLGET_VERS:
 413                 *(uint32_t *)info = rc->rc_vers;
 414                 break;
 415
 416         case CLSET_VERS:
 417                 rc->rc_vers = *(uint32_t *) info;
 418                 if (rc->rc_client)
 419                         CLNT_CONTROL(rc->rc_client, CLSET_VERS, info);
 420                 break;
 421
 422         case CLGET_PROG:
 423                 *(uint32_t *)info = rc->rc_prog;
 424                 break;
 425
 426         case CLSET_PROG:
 427                 rc->rc_prog = *(uint32_t *) info;
 428                 if (rc->rc_client)
 429                         CLNT_CONTROL(rc->rc_client, request, info);
 430                 break;
 431
 432         case CLSET_WAITCHAN:
 433                 rc->rc_waitchan = (char *)info;
 434                 if (rc->rc_client)
 435                         CLNT_CONTROL(rc->rc_client, request, info);
 436                 break;
 437
 438         case CLGET_WAITCHAN:
 439                 *(const char **) info = rc->rc_waitchan;
 440                 break;
 441
 442         case CLSET_INTERRUPTIBLE:
 443                 rc->rc_intr = *(int *) info;
 444                 if (rc->rc_client)
 445                         CLNT_CONTROL(rc->rc_client, request, info);
 446                 break;
 447
 448         case CLGET_INTERRUPTIBLE:
 449                 *(int *) info = rc->rc_intr;
 450                 break;
 451
 452         case CLSET_RETRIES:
 453                 rc->rc_retries = *(int *) info;
 454                 break;
 455
 456         case CLGET_RETRIES:
 457                 *(int *) info = rc->rc_retries;
 458                 break;
 459
 460         case CLSET_PRIVPORT:
 461                 rc->rc_privport = *(int *) info;
 462                 break;
 463
 464         case CLGET_PRIVPORT:
 465                 *(int *) info = rc->rc_privport;
 466                 break;
 467
 468         default:
 469                 return (FALSE);
 470         }
 471
 472         return (TRUE);
 473 }
 474
 475 static void
 476 clnt_reconnect_close(CLIENT *cl)
 477 {
 478         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 479         CLIENT *client;
 480
 481         mtx_lock(&rc->rc_lock);
 482
 483         if (rc->rc_closed) {
 484                 mtx_unlock(&rc->rc_lock);
 485                 return;
 486         }
 487
 488         rc->rc_closed = TRUE;
 489         client = rc->rc_client;
 490         rc->rc_client = NULL;
 491
 492         mtx_unlock(&rc->rc_lock);
 493
 494         if (client) {
 495                 CLNT_CLOSE(client);
 496                 CLNT_RELEASE(client);
 497         }
 498 }
 499
 500 static void
 501 clnt_reconnect_destroy(CLIENT *cl)
 502 {
 503         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 504
 505         if (rc->rc_client)
 506                 CLNT_DESTROY(rc->rc_client);
 507         crfree(rc->rc_ucred);
 508         mtx_destroy(&rc->rc_lock);
 509         mem_free(rc, sizeof(*rc));
 510         mem_free(cl, sizeof (CLIENT));
 511 }