Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/rpc/clnt_rc.c
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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: releng/11.2/sys/rpc/clnt_rc.c 317466 2017-04-26 22:04:55Z rmacklem $"); 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 : 0, "rpccon", hz); 251 if (error == EINTR || error == ERESTART) 252 return (RPC_INTR); 253 tries++; 254 if (tries >= rc->rc_retries) 255 return (stat); 256 continue; 257 } 258 if (stat != RPC_SUCCESS) 259 return (stat); 260 mtx_lock(&rc->rc_lock); 261 } 262 263 if (!rc->rc_client) { 264 mtx_unlock(&rc->rc_lock); 265 stat = RPC_FAILED; 266 continue; 267 } 268 CLNT_ACQUIRE(rc->rc_client); 269 client = rc->rc_client; 270 mtx_unlock(&rc->rc_lock); 271 stat = CLNT_CALL_MBUF(client, ext, proc, args, 272 resultsp, utimeout); 273 274 if (stat != RPC_SUCCESS) { 275 if (!ext) 276 CLNT_GETERR(client, &rc->rc_err); 277 } 278 279 if (stat == RPC_TIMEDOUT) { 280 /* 281 * Check for async send misfeature for NLM 282 * protocol. 283 */ 284 if ((rc->rc_timeout.tv_sec == 0 285 && rc->rc_timeout.tv_usec == 0) 286 || (rc->rc_timeout.tv_sec == -1 287 && utimeout.tv_sec == 0 288 && utimeout.tv_usec == 0)) { 289 CLNT_RELEASE(client); 290 break; 291 } 292 } 293 294 if (stat == RPC_TIMEDOUT || stat == RPC_CANTSEND 295 || stat == RPC_CANTRECV) { 296 tries++; 297 if (tries >= rc->rc_retries) { 298 CLNT_RELEASE(client); 299 break; 300 } 301 302 if (ext && ext->rc_feedback) 303 ext->rc_feedback(FEEDBACK_RECONNECT, proc, 304 ext->rc_feedback_arg); 305 306 mtx_lock(&rc->rc_lock); 307 /* 308 * Make sure that someone else hasn't already 309 * reconnected by checking if rc_client has changed. 310 * If not, we are done with the client and must 311 * do CLNT_RELEASE(client) twice to dispose of it, 312 * because there is both an initial refcnt and one 313 * acquired by CLNT_ACQUIRE() above. 314 */ 315 if (rc->rc_client == client) { 316 rc->rc_client = NULL; 317 mtx_unlock(&rc->rc_lock); 318 CLNT_RELEASE(client); 319 } else { 320 mtx_unlock(&rc->rc_lock); 321 } 322 CLNT_RELEASE(client); 323 } else { 324 CLNT_RELEASE(client); 325 break; 326 } 327 } while (stat != RPC_SUCCESS); 328 329 KASSERT(stat != RPC_SUCCESS || *resultsp, 330 ("RPC_SUCCESS without reply")); 331 332 return (stat); 333 } 334 335 static void 336 clnt_reconnect_geterr(CLIENT *cl, struct rpc_err *errp) 337 { 338 struct rc_data *rc = (struct rc_data *)cl->cl_private; 339 340 *errp = rc->rc_err; 341 } 342 343 /* 344 * Since this function requires that rc_client be valid, it can 345 * only be called when that is guaranteed to be the case. 346 */ 347 static bool_t 348 clnt_reconnect_freeres(CLIENT *cl, xdrproc_t xdr_res, void *res_ptr) 349 { 350 struct rc_data *rc = (struct rc_data *)cl->cl_private; 351 352 return (CLNT_FREERES(rc->rc_client, xdr_res, res_ptr)); 353 } 354 355 /*ARGSUSED*/ 356 static void 357 clnt_reconnect_abort(CLIENT *h) 358 { 359 } 360 361 /* 362 * CLNT_CONTROL() on the client returned by clnt_reconnect_create() must 363 * always be called before CLNT_CALL_MBUF() by a single thread only. 364 */ 365 static bool_t 366 clnt_reconnect_control(CLIENT *cl, u_int request, void *info) 367 { 368 struct rc_data *rc = (struct rc_data *)cl->cl_private; 369 SVCXPRT *xprt; 370 371 if (info == NULL) { 372 return (FALSE); 373 } 374 switch (request) { 375 case CLSET_TIMEOUT: 376 rc->rc_timeout = *(struct timeval *)info; 377 if (rc->rc_client) 378 CLNT_CONTROL(rc->rc_client, request, info); 379 break; 380 381 case CLGET_TIMEOUT: 382 *(struct timeval *)info = rc->rc_timeout; 383 break; 384 385 case CLSET_RETRY_TIMEOUT: 386 rc->rc_retry = *(struct timeval *)info; 387 if (rc->rc_client) 388 CLNT_CONTROL(rc->rc_client, request, info); 389 break; 390 391 case CLGET_RETRY_TIMEOUT: 392 *(struct timeval *)info = rc->rc_retry; 393 break; 394 395 case CLGET_VERS: 396 *(uint32_t *)info = rc->rc_vers; 397 break; 398 399 case CLSET_VERS: 400 rc->rc_vers = *(uint32_t *) info; 401 if (rc->rc_client) 402 CLNT_CONTROL(rc->rc_client, CLSET_VERS, info); 403 break; 404 405 case CLGET_PROG: 406 *(uint32_t *)info = rc->rc_prog; 407 break; 408 409 case CLSET_PROG: 410 rc->rc_prog = *(uint32_t *) info; 411 if (rc->rc_client) 412 CLNT_CONTROL(rc->rc_client, request, info); 413 break; 414 415 case CLSET_WAITCHAN: 416 rc->rc_waitchan = (char *)info; 417 if (rc->rc_client) 418 CLNT_CONTROL(rc->rc_client, request, info); 419 break; 420 421 case CLGET_WAITCHAN: 422 *(const char **) info = rc->rc_waitchan; 423 break; 424 425 case CLSET_INTERRUPTIBLE: 426 rc->rc_intr = *(int *) info; 427 if (rc->rc_client) 428 CLNT_CONTROL(rc->rc_client, request, info); 429 break; 430 431 case CLGET_INTERRUPTIBLE: 432 *(int *) info = rc->rc_intr; 433 break; 434 435 case CLSET_RETRIES: 436 rc->rc_retries = *(int *) info; 437 break; 438 439 case CLGET_RETRIES: 440 *(int *) info = rc->rc_retries; 441 break; 442 443 case CLSET_PRIVPORT: 444 rc->rc_privport = *(int *) info; 445 break; 446 447 case CLGET_PRIVPORT: 448 *(int *) info = rc->rc_privport; 449 break; 450 451 case CLSET_BACKCHANNEL: 452 xprt = (SVCXPRT *)info; 453 xprt_register(xprt); 454 rc->rc_backchannel = info; 455 break; 456 457 default: 458 return (FALSE); 459 } 460 461 return (TRUE); 462 } 463 464 static void 465 clnt_reconnect_close(CLIENT *cl) 466 { 467 struct rc_data *rc = (struct rc_data *)cl->cl_private; 468 CLIENT *client; 469 470 mtx_lock(&rc->rc_lock); 471 472 if (rc->rc_closed) { 473 mtx_unlock(&rc->rc_lock); 474 return; 475 } 476 477 rc->rc_closed = TRUE; 478 client = rc->rc_client; 479 rc->rc_client = NULL; 480 481 mtx_unlock(&rc->rc_lock); 482 483 if (client) { 484 CLNT_CLOSE(client); 485 CLNT_RELEASE(client); 486 } 487 } 488 489 static void 490 clnt_reconnect_destroy(CLIENT *cl) 491 { 492 struct rc_data *rc = (struct rc_data *)cl->cl_private; 493 SVCXPRT *xprt; 494 495 if (rc->rc_client) 496 CLNT_DESTROY(rc->rc_client); 497 if (rc->rc_backchannel) { 498 xprt = (SVCXPRT *)rc->rc_backchannel; 499 xprt_unregister(xprt); 500 SVC_RELEASE(xprt); 501 } 502 crfree(rc->rc_ucred); 503 mtx_destroy(&rc->rc_lock); 504 mem_free(rc, sizeof(*rc)); 505 mem_free(cl, sizeof (CLIENT)); 506 }
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