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 #include <rpc/krpc.h>
  49
  50 static enum clnt_stat clnt_reconnect_call(CLIENT *, struct rpc_callextra *,
  51     rpcproc_t, struct mbuf *, struct mbuf **, struct timeval);
  52 static void clnt_reconnect_geterr(CLIENT *, struct rpc_err *);
  53 static bool_t clnt_reconnect_freeres(CLIENT *, xdrproc_t, void *);
  54 static void clnt_reconnect_abort(CLIENT *);
  55 static bool_t clnt_reconnect_control(CLIENT *, u_int, void *);
  56 static void clnt_reconnect_close(CLIENT *);
  57 static void clnt_reconnect_destroy(CLIENT *);
  58
  59 static struct clnt_ops clnt_reconnect_ops = {
  60         .cl_call =      clnt_reconnect_call,
  61         .cl_abort =     clnt_reconnect_abort,
  62         .cl_geterr =    clnt_reconnect_geterr,
  63         .cl_freeres =   clnt_reconnect_freeres,
  64         .cl_close =     clnt_reconnect_close,
  65         .cl_destroy =   clnt_reconnect_destroy,
  66         .cl_control =   clnt_reconnect_control
  67 };
  68
  69 static int      fake_wchan;
  70
  71 CLIENT *
  72 clnt_reconnect_create(
  73         struct netconfig *nconf,        /* network type */
  74         struct sockaddr *svcaddr,       /* servers address */
  75         rpcprog_t program,              /* program number */
  76         rpcvers_t version,              /* version number */
  77         size_t sendsz,                  /* buffer recv size */
  78         size_t recvsz)                  /* buffer send size */
  79 {
  80         CLIENT *cl = NULL;              /* client handle */
  81         struct rc_data *rc = NULL;      /* private data */
  82
  83         if (svcaddr == NULL) {
  84                 rpc_createerr.cf_stat = RPC_UNKNOWNADDR;
  85                 return (NULL);
  86         }
  87
  88         cl = mem_alloc(sizeof (CLIENT));
  89         rc = mem_alloc(sizeof (*rc));
  90         mtx_init(&rc->rc_lock, "rc->rc_lock", NULL, MTX_DEF);
  91         (void) memcpy(&rc->rc_addr, svcaddr, (size_t)svcaddr->sa_len);
  92         rc->rc_nconf = nconf;
  93         rc->rc_prog = program;
  94         rc->rc_vers = version;
  95         rc->rc_sendsz = sendsz;
  96         rc->rc_recvsz = recvsz;
  97         rc->rc_timeout.tv_sec = -1;
  98         rc->rc_timeout.tv_usec = -1;
  99         rc->rc_retry.tv_sec = 3;
 100         rc->rc_retry.tv_usec = 0;
 101         rc->rc_retries = INT_MAX;
 102         rc->rc_privport = FALSE;
 103         rc->rc_waitchan = "rpcrecv";
 104         rc->rc_intr = 0;
 105         rc->rc_connecting = FALSE;
 106         rc->rc_closed = FALSE;
 107         rc->rc_ucred = crdup(curthread->td_ucred);
 108         rc->rc_client = NULL;
 109
 110         cl->cl_refs = 1;
 111         cl->cl_ops = &clnt_reconnect_ops;
 112         cl->cl_private = (caddr_t)(void *)rc;
 113         cl->cl_auth = authnone_create();
 114         cl->cl_tp = NULL;
 115         cl->cl_netid = NULL;
 116         return (cl);
 117 }
 118
 119 static enum clnt_stat
 120 clnt_reconnect_connect(CLIENT *cl)
 121 {
 122         struct thread *td = curthread;
 123         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 124         struct socket *so;
 125         enum clnt_stat stat;
 126         int error;
 127         int one = 1;
 128         struct ucred *oldcred;
 129         CLIENT *newclient = NULL;
 130
 131         mtx_lock(&rc->rc_lock);
 132         while (rc->rc_connecting) {
 133                 error = msleep(rc, &rc->rc_lock,
 134                     rc->rc_intr ? PCATCH : 0, "rpcrecon", 0);
 135                 if (error) {
 136                         mtx_unlock(&rc->rc_lock);
 137                         return (RPC_INTR);
 138                 }
 139         }
 140         if (rc->rc_closed) {
 141                 mtx_unlock(&rc->rc_lock);
 142                 return (RPC_CANTSEND);
 143         }
 144         if (rc->rc_client) {
 145                 mtx_unlock(&rc->rc_lock);
 146                 return (RPC_SUCCESS);
 147         }
 148
 149         /*
 150          * My turn to attempt a connect. The rc_connecting variable
 151          * serializes the following code sequence, so it is guaranteed
 152          * that rc_client will still be NULL after it is re-locked below,
 153          * since that is the only place it is set non-NULL.
 154          */
 155         rc->rc_connecting = TRUE;
 156         mtx_unlock(&rc->rc_lock);
 157
 158         oldcred = td->td_ucred;
 159         td->td_ucred = rc->rc_ucred;
 160         so = __rpc_nconf2socket(rc->rc_nconf);
 161         if (!so) {
 162                 stat = rpc_createerr.cf_stat = RPC_TLIERROR;
 163                 rpc_createerr.cf_error.re_errno = 0;
 164                 td->td_ucred = oldcred;
 165                 goto out;
 166         }
 167
 168         if (rc->rc_privport)
 169                 bindresvport(so, NULL);
 170
 171         if (rc->rc_nconf->nc_semantics == NC_TPI_CLTS)
 172                 newclient = clnt_dg_create(so,
 173                     (struct sockaddr *) &rc->rc_addr, rc->rc_prog, rc->rc_vers,
 174                     rc->rc_sendsz, rc->rc_recvsz);
 175         else
 176                 newclient = clnt_vc_create(so,
 177                     (struct sockaddr *) &rc->rc_addr, rc->rc_prog, rc->rc_vers,
 178                     rc->rc_sendsz, rc->rc_recvsz, rc->rc_intr);
 179         td->td_ucred = oldcred;
 180
 181         if (!newclient) {
 182                 soclose(so);
 183                 rc->rc_err = rpc_createerr.cf_error;
 184                 stat = rpc_createerr.cf_stat;
 185                 goto out;
 186         }
 187
 188         CLNT_CONTROL(newclient, CLSET_FD_CLOSE, 0);
 189         CLNT_CONTROL(newclient, CLSET_CONNECT, &one);
 190         CLNT_CONTROL(newclient, CLSET_TIMEOUT, &rc->rc_timeout);
 191         CLNT_CONTROL(newclient, CLSET_RETRY_TIMEOUT, &rc->rc_retry);
 192         CLNT_CONTROL(newclient, CLSET_WAITCHAN, rc->rc_waitchan);
 193         CLNT_CONTROL(newclient, CLSET_INTERRUPTIBLE, &rc->rc_intr);
 194         if (rc->rc_backchannel != NULL)
 195                 CLNT_CONTROL(newclient, CLSET_BACKCHANNEL, rc->rc_backchannel);
 196         stat = RPC_SUCCESS;
 197
 198 out:
 199         mtx_lock(&rc->rc_lock);
 200         KASSERT(rc->rc_client == NULL, ("rc_client not null"));
 201         if (!rc->rc_closed) {
 202                 rc->rc_client = newclient;
 203                 newclient = NULL;
 204         }
 205         rc->rc_connecting = FALSE;
 206         wakeup(rc);
 207         mtx_unlock(&rc->rc_lock);
 208
 209         if (newclient) {
 210                 /*
 211                  * It has been closed, so discard the new client.
 212                  * nb: clnt_[dg|vc]_close()/clnt_[dg|vc]_destroy() cannot
 213                  * be called with the rc_lock mutex held, since they may
 214                  * msleep() while holding a different mutex.
 215                  */
 216                 CLNT_CLOSE(newclient);
 217                 CLNT_RELEASE(newclient);
 218         }
 219
 220         return (stat);
 221 }
 222
 223 static enum clnt_stat
 224 clnt_reconnect_call(
 225         CLIENT          *cl,            /* client handle */
 226         struct rpc_callextra *ext,      /* call metadata */
 227         rpcproc_t       proc,           /* procedure number */
 228         struct mbuf     *args,          /* pointer to args */
 229         struct mbuf     **resultsp,     /* pointer to results */
 230         struct timeval  utimeout)
 231 {
 232         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 233         CLIENT *client;
 234         enum clnt_stat stat;
 235         int tries, error;
 236
 237         tries = 0;
 238         do {
 239                 mtx_lock(&rc->rc_lock);
 240                 if (rc->rc_closed) {
 241                         mtx_unlock(&rc->rc_lock);
 242                         return (RPC_CANTSEND);
 243                 }
 244
 245                 if (!rc->rc_client) {
 246                         mtx_unlock(&rc->rc_lock);
 247                         stat = clnt_reconnect_connect(cl);
 248                         if (stat == RPC_SYSTEMERROR) {
 249                                 error = tsleep(&fake_wchan,
 250                                     rc->rc_intr ? PCATCH | PBDRY : 0, "rpccon",
 251                                     hz);
 252                                 if (error == EINTR || error == ERESTART)
 253                                         return (RPC_INTR);
 254                                 tries++;
 255                                 if (tries >= rc->rc_retries)
 256                                         return (stat);
 257                                 continue;
 258                         }
 259                         if (stat != RPC_SUCCESS)
 260                                 return (stat);
 261                         mtx_lock(&rc->rc_lock);
 262                 }
 263
 264                 if (!rc->rc_client) {
 265                         mtx_unlock(&rc->rc_lock);
 266                         stat = RPC_FAILED;
 267                         continue;
 268                 }
 269                 CLNT_ACQUIRE(rc->rc_client);
 270                 client = rc->rc_client;
 271                 mtx_unlock(&rc->rc_lock);
 272                 stat = CLNT_CALL_MBUF(client, ext, proc, args,
 273                     resultsp, utimeout);
 274
 275                 if (stat != RPC_SUCCESS) {
 276                         if (!ext)
 277                                 CLNT_GETERR(client, &rc->rc_err);
 278                 }
 279
 280                 if (stat == RPC_TIMEDOUT) {
 281                         /*
 282                          * Check for async send misfeature for NLM
 283                          * protocol.
 284                          */
 285                         if ((rc->rc_timeout.tv_sec == 0
 286                                 && rc->rc_timeout.tv_usec == 0)
 287                             || (rc->rc_timeout.tv_sec == -1
 288                                 && utimeout.tv_sec == 0
 289                                 && utimeout.tv_usec == 0)) {
 290                                 CLNT_RELEASE(client);
 291                                 break;
 292                         }
 293                 }
 294
 295                 if (stat == RPC_TIMEDOUT || stat == RPC_CANTSEND
 296                     || stat == RPC_CANTRECV) {
 297                         tries++;
 298                         if (tries >= rc->rc_retries) {
 299                                 CLNT_RELEASE(client);
 300                                 break;
 301                         }
 302
 303                         if (ext && ext->rc_feedback)
 304                                 ext->rc_feedback(FEEDBACK_RECONNECT, proc,
 305                                     ext->rc_feedback_arg);
 306
 307                         mtx_lock(&rc->rc_lock);
 308                         /*
 309                          * Make sure that someone else hasn't already
 310                          * reconnected by checking if rc_client has changed.
 311                          * If not, we are done with the client and must
 312                          * do CLNT_RELEASE(client) twice to dispose of it,
 313                          * because there is both an initial refcnt and one
 314                          * acquired by CLNT_ACQUIRE() above.
 315                          */
 316                         if (rc->rc_client == client) {
 317                                 rc->rc_client = NULL;
 318                                 mtx_unlock(&rc->rc_lock);
 319                                 CLNT_RELEASE(client);
 320                         } else {
 321                                 mtx_unlock(&rc->rc_lock);
 322                         }
 323                         CLNT_RELEASE(client);
 324                 } else {
 325                         CLNT_RELEASE(client);
 326                         break;
 327                 }
 328         } while (stat != RPC_SUCCESS);
 329
 330         KASSERT(stat != RPC_SUCCESS || *resultsp,
 331             ("RPC_SUCCESS without reply"));
 332
 333         return (stat);
 334 }
 335
 336 static void
 337 clnt_reconnect_geterr(CLIENT *cl, struct rpc_err *errp)
 338 {
 339         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 340
 341         *errp = rc->rc_err;
 342 }
 343
 344 /*
 345  * Since this function requires that rc_client be valid, it can
 346  * only be called when that is guaranteed to be the case.
 347  */
 348 static bool_t
 349 clnt_reconnect_freeres(CLIENT *cl, xdrproc_t xdr_res, void *res_ptr)
 350 {
 351         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 352
 353         return (CLNT_FREERES(rc->rc_client, xdr_res, res_ptr));
 354 }
 355
 356 /*ARGSUSED*/
 357 static void
 358 clnt_reconnect_abort(CLIENT *h)
 359 {
 360 }
 361
 362 /*
 363  * CLNT_CONTROL() on the client returned by clnt_reconnect_create() must
 364  * always be called before CLNT_CALL_MBUF() by a single thread only.
 365  */
 366 static bool_t
 367 clnt_reconnect_control(CLIENT *cl, u_int request, void *info)
 368 {
 369         struct rc_data *rc = (struct rc_data *)cl->cl_private;
 370         SVCXPRT *xprt;
 371
 372         if (info == NULL) {
 373                 return (FALSE);
 374         }
 375         switch (request) {
 376         case CLSET_TIMEOUT:
 377                 rc->rc_timeout = *(struct timeval *)info;
 378                 if (rc->rc_client)
 379                         CLNT_CONTROL(rc->rc_client, request, info);
 380                 break;
 381
 382         case CLGET_TIMEOUT:
 383                 *(struct timeval *)info = rc->rc_timeout;
 384                 break;
 385
 386         case CLSET_RETRY_TIMEOUT:
 387                 rc->rc_retry = *(struct timeval *)info;
 388                 if (rc->rc_client)
 389                         CLNT_CONTROL(rc->rc_client, request, info);
 390                 break;
 391
 392         case CLGET_RETRY_TIMEOUT:
 393                 *(struct timeval *)info = rc->rc_retry;
 394                 break;
 395
 396         case CLGET_VERS:
 397                 *(uint32_t *)info = rc->rc_vers;
 398                 break;
 399
 400         case CLSET_VERS:
 401                 rc->rc_vers = *(uint32_t *) info;
 402                 if (rc->rc_client)
 403                         CLNT_CONTROL(rc->rc_client, CLSET_VERS, info);
 404                 break;
 405
 406         case CLGET_PROG:
 407                 *(uint32_t *)info = rc->rc_prog;
 408                 break;
 409
 410         case CLSET_PROG:
 411                 rc->rc_prog = *(uint32_t *) info;
 412                 if (rc->rc_client)
 413                         CLNT_CONTROL(rc->rc_client, request, info);
 414                 break;
 415
 416         case CLSET_WAITCHAN:
 417                 rc->rc_waitchan = (char *)info;
 418                 if (rc->rc_client)
 419                         CLNT_CONTROL(rc->rc_client, request, info);
 420                 break;
 421
 422         case CLGET_WAITCHAN:
 423                 *(const char **) info = rc->rc_waitchan;
 424                 break;
 425
 426         case CLSET_INTERRUPTIBLE:
 427                 rc->rc_intr = *(int *) info;
 428                 if (rc->rc_client)
 429                         CLNT_CONTROL(rc->rc_client, request, info);
 430                 break;
 431
 432         case CLGET_INTERRUPTIBLE:
 433                 *(int *) info = rc->rc_intr;
 434                 break;
 435
 436         case CLSET_RETRIES:
 437                 rc->rc_retries = *(int *) info;
 438                 break;
 439
 440         case CLGET_RETRIES:
 441                 *(int *) info = rc->rc_retries;
 442                 break;
 443
 444         case CLSET_PRIVPORT:
 445                 rc->rc_privport = *(int *) info;
 446                 break;
 447
 448         case CLGET_PRIVPORT:
 449                 *(int *) info = rc->rc_privport;
 450                 break;
 451
 452         case CLSET_BACKCHANNEL:
 453                 xprt = (SVCXPRT *)info;
 454                 SVC_ACQUIRE(xprt);
 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 }