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 * 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: releng/12.0/sys/rpc/clnt_rc.c 336542 2018-07-20 12:03:16Z rmacklem $"); 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 }
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