sys/rpc/clnt_rc.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2008 Isilon Inc http://www.isilon.com/
   5  * Authors: Doug Rabson <dfr@rabson.org>
   6  * Developed with Red Inc: Alfred Perlstein <alfred@freebsd.org>
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include <sys/cdefs.h>
  31 __FBSDID("$FreeBSD$");
  32
  33 #include <sys/param.h>
  34 #include <sys/systm.h>
  35 #include <sys/kernel.h>
  36 #include <sys/limits.h>
  37 #include <sys/lock.h>
  38 #include <sys/malloc.h>
  39 #include <sys/mbuf.h>
  40 #include <sys/mutex.h>
  41 #include <sys/pcpu.h>
  42 #include <sys/proc.h>
  43 #include <sys/socket.h>
  44 #include <sys/socketvar.h>
  45 #include <sys/time.h>
  46 #include <sys/uio.h>
  47
  48 #include <rpc/rpc.h>
  49 #include <rpc/rpc_com.h>
  50 #include <rpc/krpc.h>
  51
  52 static enum clnt_stat clnt_reconnect_call(CLIENT *, struct rpc_callextra *,
  53     rpcproc_t, struct mbuf *, struct mbuf **, struct timeval);
  54 static void clnt_reconnect_geterr(CLIENT *, struct rpc_err *);
  55 static bool_t clnt_reconnect_freeres(CLIENT *, xdrproc_t, void *);
  56 static void clnt_reconnect_abort(CLIENT *);
  57 static bool_t clnt_reconnect_control(CLIENT *, u_int, void *);
  58 static void clnt_reconnect_close(CLIENT *);
  59 static void clnt_reconnect_destroy(CLIENT *);
  60
  61 static struct clnt_ops clnt_reconnect_ops = {
  62         .cl_call =      clnt_reconnect_call,
  63         .cl_abort =     clnt_reconnect_abort,
  64         .cl_geterr =    clnt_reconnect_geterr,
  65         .cl_freeres =   clnt_reconnect_freeres,
  66         .cl_close =     clnt_reconnect_close,
  67         .cl_destroy =   clnt_reconnect_destroy,
  68         .cl_control =   clnt_reconnect_control
  69 };
  70
  71 static int      fake_wchan;
  72
  73 CLIENT *
  74 clnt_reconnect_create(
  75         struct netconfig *nconf,        /* network type */
  76         struct sockaddr *svcaddr,       /* servers address */
  77         rpcprog_t program,              /* program number */
  78         rpcvers_t version,              /* version number */
  79         size_t sendsz,                  /* buffer recv size */
  80         size_t recvsz)                  /* buffer send size */
  81 {
  82         CLIENT *cl = NULL;              /* client handle */
  83         struct rc_data *rc = NULL;      /* private data */
  84
  85         if (svcaddr == NULL) {
  86                 rpc_createerr.cf_stat = RPC_UNKNOWNADDR;
  87                 return (NULL);
  88         }
  89
  90         cl = mem_alloc(sizeof (CLIENT));
  91         rc = mem_alloc(sizeof (*rc));
  92         mtx_init(&rc->rc_lock, "rc->rc_lock", NULL, MTX_DEF);
  93         (void) memcpy(&rc->rc_addr, svcaddr, (size_t)svcaddr->sa_len);
  94         rc->rc_nconf = nconf;
  95         rc->rc_prog = program;
  96         rc->rc_vers = version;
  97         rc->rc_sendsz = sendsz;
  98         rc->rc_recvsz = recvsz;
  99         rc->rc_timeout.tv_sec = -1;
 100         rc->rc_timeout.tv_usec = -1;
 101         rc->rc_retry.tv_sec = 3;
 102         rc->rc_retry.tv_usec = 0;
 103         rc->rc_retries = INT_MAX;
 104         rc->rc_privport = FALSE;
 105         rc->rc_waitchan = "rpcrecv";
 106         rc->rc_intr = 0;
 107         rc->rc_connecting = FALSE;
 108         rc->rc_closed = FALSE;
 109         rc->rc_ucred = crdup(curthread->td_ucred);
 110         rc->rc_client = NULL;
 111
 112         cl->cl_refs = 1;
 113         cl->cl_ops = &clnt_reconnect_ops;
 114         cl->cl_private = (caddr_t)(void *)rc;
 115         cl->cl_auth = authnone_create();
 116         cl->cl_tp = NULL;
 117         cl->cl_netid = NULL;
 118         return (cl);
 119 }
 120
 121 static enum clnt_stat
 122 clnt_reconnect_connect(CLIENT *cl)
 123 {
 124         struct thread *td = curthread;
 125         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 126         struct socket *so;
 127         enum clnt_stat stat;
 128         int error;
 129         int one = 1;
 130         struct ucred *oldcred;
 131         CLIENT *newclient = NULL;
 132
 133         mtx_lock(&rc->rc_lock);
 134         while (rc->rc_connecting) {
 135                 error = msleep(rc, &rc->rc_lock,
 136                     rc->rc_intr ? PCATCH : 0, "rpcrecon", 0);
 137                 if (error) {
 138                         mtx_unlock(&rc->rc_lock);
 139                         return (RPC_INTR);
 140                 }
 141         }
 142         if (rc->rc_closed) {
 143                 mtx_unlock(&rc->rc_lock);
 144                 return (RPC_CANTSEND);
 145         }
 146         if (rc->rc_client) {
 147                 mtx_unlock(&rc->rc_lock);
 148                 return (RPC_SUCCESS);
 149         }
 150
 151         /*
 152          * My turn to attempt a connect. The rc_connecting variable
 153          * serializes the following code sequence, so it is guaranteed
 154          * that rc_client will still be NULL after it is re-locked below,
 155          * since that is the only place it is set non-NULL.
 156          */
 157         rc->rc_connecting = TRUE;
 158         mtx_unlock(&rc->rc_lock);
 159
 160         oldcred = td->td_ucred;
 161         td->td_ucred = rc->rc_ucred;
 162         so = __rpc_nconf2socket(rc->rc_nconf);
 163         if (!so) {
 164                 stat = rpc_createerr.cf_stat = RPC_TLIERROR;
 165                 rpc_createerr.cf_error.re_errno = 0;
 166                 td->td_ucred = oldcred;
 167                 goto out;
 168         }
 169
 170         if (rc->rc_privport)
 171                 bindresvport(so, NULL);
 172
 173         if (rc->rc_nconf->nc_semantics == NC_TPI_CLTS)
 174                 newclient = clnt_dg_create(so,
 175                     (struct sockaddr *) &rc->rc_addr, rc->rc_prog, rc->rc_vers,
 176                     rc->rc_sendsz, rc->rc_recvsz);
 177         else {
 178                 /*
 179                  * I do not believe a timeout of less than 1sec would make
 180                  * sense here since short delays can occur when a server is
 181                  * temporarily overloaded.
 182                  */
 183                 if (rc->rc_timeout.tv_sec > 0 && rc->rc_timeout.tv_usec >= 0) {
 184                         error = so_setsockopt(so, SOL_SOCKET, SO_SNDTIMEO,
 185                             &rc->rc_timeout, sizeof(struct timeval));
 186                         if (error != 0) {
 187                                 stat = rpc_createerr.cf_stat = RPC_CANTSEND;
 188                                 rpc_createerr.cf_error.re_errno = error;
 189                                 td->td_ucred = oldcred;
 190                                 goto out;
 191                         }
 192                 }
 193                 newclient = clnt_vc_create(so,
 194                     (struct sockaddr *) &rc->rc_addr, rc->rc_prog, rc->rc_vers,
 195                     rc->rc_sendsz, rc->rc_recvsz, rc->rc_intr);
 196         }
 197         td->td_ucred = oldcred;
 198
 199         if (!newclient) {
 200                 soclose(so);
 201                 rc->rc_err = rpc_createerr.cf_error;
 202                 stat = rpc_createerr.cf_stat;
 203                 goto out;
 204         }
 205
 206         CLNT_CONTROL(newclient, CLSET_FD_CLOSE, 0);
 207         CLNT_CONTROL(newclient, CLSET_CONNECT, &one);
 208         CLNT_CONTROL(newclient, CLSET_TIMEOUT, &rc->rc_timeout);
 209         CLNT_CONTROL(newclient, CLSET_RETRY_TIMEOUT, &rc->rc_retry);
 210         CLNT_CONTROL(newclient, CLSET_WAITCHAN, rc->rc_waitchan);
 211         CLNT_CONTROL(newclient, CLSET_INTERRUPTIBLE, &rc->rc_intr);
 212         if (rc->rc_backchannel != NULL)
 213                 CLNT_CONTROL(newclient, CLSET_BACKCHANNEL, rc->rc_backchannel);
 214         stat = RPC_SUCCESS;
 215
 216 out:
 217         mtx_lock(&rc->rc_lock);
 218         KASSERT(rc->rc_client == NULL, ("rc_client not null"));
 219         if (!rc->rc_closed) {
 220                 rc->rc_client = newclient;
 221                 newclient = NULL;
 222         }
 223         rc->rc_connecting = FALSE;
 224         wakeup(rc);
 225         mtx_unlock(&rc->rc_lock);
 226
 227         if (newclient) {
 228                 /*
 229                  * It has been closed, so discard the new client.
 230                  * nb: clnt_[dg|vc]_close()/clnt_[dg|vc]_destroy() cannot
 231                  * be called with the rc_lock mutex held, since they may
 232                  * msleep() while holding a different mutex.
 233                  */
 234                 CLNT_CLOSE(newclient);
 235                 CLNT_RELEASE(newclient);
 236         }
 237
 238         return (stat);
 239 }
 240
 241 static enum clnt_stat
 242 clnt_reconnect_call(
 243         CLIENT          *cl,            /* client handle */
 244         struct rpc_callextra *ext,      /* call metadata */
 245         rpcproc_t       proc,           /* procedure number */
 246         struct mbuf     *args,          /* pointer to args */
 247         struct mbuf     **resultsp,     /* pointer to results */
 248         struct timeval  utimeout)
 249 {
 250         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 251         CLIENT *client;
 252         enum clnt_stat stat;
 253         int tries, error;
 254
 255         tries = 0;
 256         do {
 257                 mtx_lock(&rc->rc_lock);
 258                 if (rc->rc_closed) {
 259                         mtx_unlock(&rc->rc_lock);
 260                         return (RPC_CANTSEND);
 261                 }
 262
 263                 if (!rc->rc_client) {
 264                         mtx_unlock(&rc->rc_lock);
 265                         stat = clnt_reconnect_connect(cl);
 266                         if (stat == RPC_SYSTEMERROR) {
 267                                 error = tsleep(&fake_wchan,
 268                                     rc->rc_intr ? PCATCH : 0, "rpccon", 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         SVCXPRT *xprt;
 388
 389         if (info == NULL) {
 390                 return (FALSE);
 391         }
 392         switch (request) {
 393         case CLSET_TIMEOUT:
 394                 rc->rc_timeout = *(struct timeval *)info;
 395                 if (rc->rc_client)
 396                         CLNT_CONTROL(rc->rc_client, request, info);
 397                 break;
 398
 399         case CLGET_TIMEOUT:
 400                 *(struct timeval *)info = rc->rc_timeout;
 401                 break;
 402
 403         case CLSET_RETRY_TIMEOUT:
 404                 rc->rc_retry = *(struct timeval *)info;
 405                 if (rc->rc_client)
 406                         CLNT_CONTROL(rc->rc_client, request, info);
 407                 break;
 408
 409         case CLGET_RETRY_TIMEOUT:
 410                 *(struct timeval *)info = rc->rc_retry;
 411                 break;
 412
 413         case CLGET_VERS:
 414                 *(uint32_t *)info = rc->rc_vers;
 415                 break;
 416
 417         case CLSET_VERS:
 418                 rc->rc_vers = *(uint32_t *) info;
 419                 if (rc->rc_client)
 420                         CLNT_CONTROL(rc->rc_client, CLSET_VERS, info);
 421                 break;
 422
 423         case CLGET_PROG:
 424                 *(uint32_t *)info = rc->rc_prog;
 425                 break;
 426
 427         case CLSET_PROG:
 428                 rc->rc_prog = *(uint32_t *) info;
 429                 if (rc->rc_client)
 430                         CLNT_CONTROL(rc->rc_client, request, info);
 431                 break;
 432
 433         case CLSET_WAITCHAN:
 434                 rc->rc_waitchan = (char *)info;
 435                 if (rc->rc_client)
 436                         CLNT_CONTROL(rc->rc_client, request, info);
 437                 break;
 438
 439         case CLGET_WAITCHAN:
 440                 *(const char **) info = rc->rc_waitchan;
 441                 break;
 442
 443         case CLSET_INTERRUPTIBLE:
 444                 rc->rc_intr = *(int *) info;
 445                 if (rc->rc_client)
 446                         CLNT_CONTROL(rc->rc_client, request, info);
 447                 break;
 448
 449         case CLGET_INTERRUPTIBLE:
 450                 *(int *) info = rc->rc_intr;
 451                 break;
 452
 453         case CLSET_RETRIES:
 454                 rc->rc_retries = *(int *) info;
 455                 break;
 456
 457         case CLGET_RETRIES:
 458                 *(int *) info = rc->rc_retries;
 459                 break;
 460
 461         case CLSET_PRIVPORT:
 462                 rc->rc_privport = *(int *) info;
 463                 break;
 464
 465         case CLGET_PRIVPORT:
 466                 *(int *) info = rc->rc_privport;
 467                 break;
 468
 469         case CLSET_BACKCHANNEL:
 470                 xprt = (SVCXPRT *)info;
 471                 xprt_register(xprt);
 472                 rc->rc_backchannel = info;
 473                 break;
 474
 475         default:
 476                 return (FALSE);
 477         }
 478
 479         return (TRUE);
 480 }
 481
 482 static void
 483 clnt_reconnect_close(CLIENT *cl)
 484 {
 485         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 486         CLIENT *client;
 487
 488         mtx_lock(&rc->rc_lock);
 489
 490         if (rc->rc_closed) {
 491                 mtx_unlock(&rc->rc_lock);
 492                 return;
 493         }
 494
 495         rc->rc_closed = TRUE;
 496         client = rc->rc_client;
 497         rc->rc_client = NULL;
 498
 499         mtx_unlock(&rc->rc_lock);
 500
 501         if (client) {
 502                 CLNT_CLOSE(client);
 503                 CLNT_RELEASE(client);
 504         }
 505 }
 506
 507 static void
 508 clnt_reconnect_destroy(CLIENT *cl)
 509 {
 510         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 511         SVCXPRT *xprt;
 512
 513         if (rc->rc_client)
 514                 CLNT_DESTROY(rc->rc_client);
 515         if (rc->rc_backchannel) {
 516                 xprt = (SVCXPRT *)rc->rc_backchannel;
 517                 xprt_unregister(xprt);
 518                 SVC_RELEASE(xprt);
 519         }
 520         crfree(rc->rc_ucred);
 521         mtx_destroy(&rc->rc_lock);
 522         mem_free(rc, sizeof(*rc));
 523         mem_free(cl, sizeof (CLIENT));
 524 }