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                 newclient = clnt_vc_create(so,
 179                     (struct sockaddr *) &rc->rc_addr, rc->rc_prog, rc->rc_vers,
 180                     rc->rc_sendsz, rc->rc_recvsz, rc->rc_intr);
 181         td->td_ucred = oldcred;
 182
 183         if (!newclient) {
 184                 soclose(so);
 185                 rc->rc_err = rpc_createerr.cf_error;
 186                 stat = rpc_createerr.cf_stat;
 187                 goto out;
 188         }
 189
 190         CLNT_CONTROL(newclient, CLSET_FD_CLOSE, 0);
 191         CLNT_CONTROL(newclient, CLSET_CONNECT, &one);
 192         CLNT_CONTROL(newclient, CLSET_TIMEOUT, &rc->rc_timeout);
 193         CLNT_CONTROL(newclient, CLSET_RETRY_TIMEOUT, &rc->rc_retry);
 194         CLNT_CONTROL(newclient, CLSET_WAITCHAN, rc->rc_waitchan);
 195         CLNT_CONTROL(newclient, CLSET_INTERRUPTIBLE, &rc->rc_intr);
 196         if (rc->rc_backchannel != NULL)
 197                 CLNT_CONTROL(newclient, CLSET_BACKCHANNEL, rc->rc_backchannel);
 198         stat = RPC_SUCCESS;
 199
 200 out:
 201         mtx_lock(&rc->rc_lock);
 202         KASSERT(rc->rc_client == NULL, ("rc_client not null"));
 203         if (!rc->rc_closed) {
 204                 rc->rc_client = newclient;
 205                 newclient = NULL;
 206         }
 207         rc->rc_connecting = FALSE;
 208         wakeup(rc);
 209         mtx_unlock(&rc->rc_lock);
 210
 211         if (newclient) {
 212                 /*
 213                  * It has been closed, so discard the new client.
 214                  * nb: clnt_[dg|vc]_close()/clnt_[dg|vc]_destroy() cannot
 215                  * be called with the rc_lock mutex held, since they may
 216                  * msleep() while holding a different mutex.
 217                  */
 218                 CLNT_CLOSE(newclient);
 219                 CLNT_RELEASE(newclient);
 220         }
 221
 222         return (stat);
 223 }
 224
 225 static enum clnt_stat
 226 clnt_reconnect_call(
 227         CLIENT          *cl,            /* client handle */
 228         struct rpc_callextra *ext,      /* call metadata */
 229         rpcproc_t       proc,           /* procedure number */
 230         struct mbuf     *args,          /* pointer to args */
 231         struct mbuf     **resultsp,     /* pointer to results */
 232         struct timeval  utimeout)
 233 {
 234         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 235         CLIENT *client;
 236         enum clnt_stat stat;
 237         int tries, error;
 238
 239         tries = 0;
 240         do {
 241                 mtx_lock(&rc->rc_lock);
 242                 if (rc->rc_closed) {
 243                         mtx_unlock(&rc->rc_lock);
 244                         return (RPC_CANTSEND);
 245                 }
 246
 247                 if (!rc->rc_client) {
 248                         mtx_unlock(&rc->rc_lock);
 249                         stat = clnt_reconnect_connect(cl);
 250                         if (stat == RPC_SYSTEMERROR) {
 251                                 error = tsleep(&fake_wchan,
 252                                     rc->rc_intr ? PCATCH : 0, "rpccon", hz);
 253                                 if (error == EINTR || error == ERESTART)
 254                                         return (RPC_INTR);
 255                                 tries++;
 256                                 if (tries >= rc->rc_retries)
 257                                         return (stat);
 258                                 continue;
 259                         }
 260                         if (stat != RPC_SUCCESS)
 261                                 return (stat);
 262                         mtx_lock(&rc->rc_lock);
 263                 }
 264
 265                 if (!rc->rc_client) {
 266                         mtx_unlock(&rc->rc_lock);
 267                         stat = RPC_FAILED;
 268                         continue;
 269                 }
 270                 CLNT_ACQUIRE(rc->rc_client);
 271                 client = rc->rc_client;
 272                 mtx_unlock(&rc->rc_lock);
 273                 stat = CLNT_CALL_MBUF(client, ext, proc, args,
 274                     resultsp, utimeout);
 275
 276                 if (stat != RPC_SUCCESS) {
 277                         if (!ext)
 278                                 CLNT_GETERR(client, &rc->rc_err);
 279                 }
 280
 281                 if (stat == RPC_TIMEDOUT) {
 282                         /*
 283                          * Check for async send misfeature for NLM
 284                          * protocol.
 285                          */
 286                         if ((rc->rc_timeout.tv_sec == 0
 287                                 && rc->rc_timeout.tv_usec == 0)
 288                             || (rc->rc_timeout.tv_sec == -1
 289                                 && utimeout.tv_sec == 0
 290                                 && utimeout.tv_usec == 0)) {
 291                                 CLNT_RELEASE(client);
 292                                 break;
 293                         }
 294                 }
 295
 296                 if (stat == RPC_TIMEDOUT || stat == RPC_CANTSEND
 297                     || stat == RPC_CANTRECV) {
 298                         tries++;
 299                         if (tries >= rc->rc_retries) {
 300                                 CLNT_RELEASE(client);
 301                                 break;
 302                         }
 303
 304                         if (ext && ext->rc_feedback)
 305                                 ext->rc_feedback(FEEDBACK_RECONNECT, proc,
 306                                     ext->rc_feedback_arg);
 307
 308                         mtx_lock(&rc->rc_lock);
 309                         /*
 310                          * Make sure that someone else hasn't already
 311                          * reconnected by checking if rc_client has changed.
 312                          * If not, we are done with the client and must
 313                          * do CLNT_RELEASE(client) twice to dispose of it,
 314                          * because there is both an initial refcnt and one
 315                          * acquired by CLNT_ACQUIRE() above.
 316                          */
 317                         if (rc->rc_client == client) {
 318                                 rc->rc_client = NULL;
 319                                 mtx_unlock(&rc->rc_lock);
 320                                 CLNT_RELEASE(client);
 321                         } else {
 322                                 mtx_unlock(&rc->rc_lock);
 323                         }
 324                         CLNT_RELEASE(client);
 325                 } else {
 326                         CLNT_RELEASE(client);
 327                         break;
 328                 }
 329         } while (stat != RPC_SUCCESS);
 330
 331         KASSERT(stat != RPC_SUCCESS || *resultsp,
 332             ("RPC_SUCCESS without reply"));
 333
 334         return (stat);
 335 }
 336
 337 static void
 338 clnt_reconnect_geterr(CLIENT *cl, struct rpc_err *errp)
 339 {
 340         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 341
 342         *errp = rc->rc_err;
 343 }
 344
 345 /*
 346  * Since this function requires that rc_client be valid, it can
 347  * only be called when that is guaranteed to be the case.
 348  */
 349 static bool_t
 350 clnt_reconnect_freeres(CLIENT *cl, xdrproc_t xdr_res, void *res_ptr)
 351 {
 352         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 353
 354         return (CLNT_FREERES(rc->rc_client, xdr_res, res_ptr));
 355 }
 356
 357 /*ARGSUSED*/
 358 static void
 359 clnt_reconnect_abort(CLIENT *h)
 360 {
 361 }
 362
 363 /*
 364  * CLNT_CONTROL() on the client returned by clnt_reconnect_create() must
 365  * always be called before CLNT_CALL_MBUF() by a single thread only.
 366  */
 367 static bool_t
 368 clnt_reconnect_control(CLIENT *cl, u_int request, void *info)
 369 {
 370         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 371         SVCXPRT *xprt;
 372
 373         if (info == NULL) {
 374                 return (FALSE);
 375         }
 376         switch (request) {
 377         case CLSET_TIMEOUT:
 378                 rc->rc_timeout = *(struct timeval *)info;
 379                 if (rc->rc_client)
 380                         CLNT_CONTROL(rc->rc_client, request, info);
 381                 break;
 382
 383         case CLGET_TIMEOUT:
 384                 *(struct timeval *)info = rc->rc_timeout;
 385                 break;
 386
 387         case CLSET_RETRY_TIMEOUT:
 388                 rc->rc_retry = *(struct timeval *)info;
 389                 if (rc->rc_client)
 390                         CLNT_CONTROL(rc->rc_client, request, info);
 391                 break;
 392
 393         case CLGET_RETRY_TIMEOUT:
 394                 *(struct timeval *)info = rc->rc_retry;
 395                 break;
 396
 397         case CLGET_VERS:
 398                 *(uint32_t *)info = rc->rc_vers;
 399                 break;
 400
 401         case CLSET_VERS:
 402                 rc->rc_vers = *(uint32_t *) info;
 403                 if (rc->rc_client)
 404                         CLNT_CONTROL(rc->rc_client, CLSET_VERS, info);
 405                 break;
 406
 407         case CLGET_PROG:
 408                 *(uint32_t *)info = rc->rc_prog;
 409                 break;
 410
 411         case CLSET_PROG:
 412                 rc->rc_prog = *(uint32_t *) info;
 413                 if (rc->rc_client)
 414                         CLNT_CONTROL(rc->rc_client, request, info);
 415                 break;
 416
 417         case CLSET_WAITCHAN:
 418                 rc->rc_waitchan = (char *)info;
 419                 if (rc->rc_client)
 420                         CLNT_CONTROL(rc->rc_client, request, info);
 421                 break;
 422
 423         case CLGET_WAITCHAN:
 424                 *(const char **) info = rc->rc_waitchan;
 425                 break;
 426
 427         case CLSET_INTERRUPTIBLE:
 428                 rc->rc_intr = *(int *) info;
 429                 if (rc->rc_client)
 430                         CLNT_CONTROL(rc->rc_client, request, info);
 431                 break;
 432
 433         case CLGET_INTERRUPTIBLE:
 434                 *(int *) info = rc->rc_intr;
 435                 break;
 436
 437         case CLSET_RETRIES:
 438                 rc->rc_retries = *(int *) info;
 439                 break;
 440
 441         case CLGET_RETRIES:
 442                 *(int *) info = rc->rc_retries;
 443                 break;
 444
 445         case CLSET_PRIVPORT:
 446                 rc->rc_privport = *(int *) info;
 447                 break;
 448
 449         case CLGET_PRIVPORT:
 450                 *(int *) info = rc->rc_privport;
 451                 break;
 452
 453         case CLSET_BACKCHANNEL:
 454                 xprt = (SVCXPRT *)info;
 455                 xprt_register(xprt);
 456                 rc->rc_backchannel = info;
 457                 break;
 458
 459         default:
 460                 return (FALSE);
 461         }
 462
 463         return (TRUE);
 464 }
 465
 466 static void
 467 clnt_reconnect_close(CLIENT *cl)
 468 {
 469         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 470         CLIENT *client;
 471
 472         mtx_lock(&rc->rc_lock);
 473
 474         if (rc->rc_closed) {
 475                 mtx_unlock(&rc->rc_lock);
 476                 return;
 477         }
 478
 479         rc->rc_closed = TRUE;
 480         client = rc->rc_client;
 481         rc->rc_client = NULL;
 482
 483         mtx_unlock(&rc->rc_lock);
 484
 485         if (client) {
 486                 CLNT_CLOSE(client);
 487                 CLNT_RELEASE(client);
 488         }
 489 }
 490
 491 static void
 492 clnt_reconnect_destroy(CLIENT *cl)
 493 {
 494         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 495         SVCXPRT *xprt;
 496
 497         if (rc->rc_client)
 498                 CLNT_DESTROY(rc->rc_client);
 499         if (rc->rc_backchannel) {
 500                 xprt = (SVCXPRT *)rc->rc_backchannel;
 501                 xprt_unregister(xprt);
 502                 SVC_RELEASE(xprt);
 503         }
 504         crfree(rc->rc_ucred);
 505         mtx_destroy(&rc->rc_lock);
 506         mem_free(rc, sizeof(*rc));
 507         mem_free(cl, sizeof (CLIENT));
 508 }