1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1989, 1991, 1993 5 * The Regents of the University of California. All Rights Reserved. 6 * Copyright (c) 2004-2009 Robert N. M. Watson All Rights Reserved. 7 * Copyright (c) 2018 Matthew Macy 8 * Copyright (c) 2022 Gleb Smirnoff <glebius@FreeBSD.org> 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 /* 36 * UNIX Domain (Local) Sockets 37 * 38 * This is an implementation of UNIX (local) domain sockets. Each socket has 39 * an associated struct unpcb (UNIX protocol control block). Stream sockets 40 * may be connected to 0 or 1 other socket. Datagram sockets may be 41 * connected to 0, 1, or many other sockets. Sockets may be created and 42 * connected in pairs (socketpair(2)), or bound/connected to using the file 43 * system name space. For most purposes, only the receive socket buffer is 44 * used, as sending on one socket delivers directly to the receive socket 45 * buffer of a second socket. 46 * 47 * The implementation is substantially complicated by the fact that 48 * "ancillary data", such as file descriptors or credentials, may be passed 49 * across UNIX domain sockets. The potential for passing UNIX domain sockets 50 * over other UNIX domain sockets requires the implementation of a simple 51 * garbage collector to find and tear down cycles of disconnected sockets. 52 * 53 * TODO: 54 * RDM 55 * rethink name space problems 56 * need a proper out-of-band 57 */ 58 59 #include <sys/cdefs.h> 60 #include "opt_ddb.h" 61 62 #include <sys/param.h> 63 #include <sys/capsicum.h> 64 #include <sys/domain.h> 65 #include <sys/eventhandler.h> 66 #include <sys/fcntl.h> 67 #include <sys/file.h> 68 #include <sys/filedesc.h> 69 #include <sys/kernel.h> 70 #include <sys/lock.h> 71 #include <sys/malloc.h> 72 #include <sys/mbuf.h> 73 #include <sys/mount.h> 74 #include <sys/mutex.h> 75 #include <sys/namei.h> 76 #include <sys/proc.h> 77 #include <sys/protosw.h> 78 #include <sys/queue.h> 79 #include <sys/resourcevar.h> 80 #include <sys/rwlock.h> 81 #include <sys/socket.h> 82 #include <sys/socketvar.h> 83 #include <sys/signalvar.h> 84 #include <sys/stat.h> 85 #include <sys/sx.h> 86 #include <sys/sysctl.h> 87 #include <sys/systm.h> 88 #include <sys/taskqueue.h> 89 #include <sys/un.h> 90 #include <sys/unpcb.h> 91 #include <sys/vnode.h> 92 93 #include <net/vnet.h> 94 95 #ifdef DDB 96 #include <ddb/ddb.h> 97 #endif 98 99 #include <security/mac/mac_framework.h> 100 101 #include <vm/uma.h> 102 103 MALLOC_DECLARE(M_FILECAPS); 104 105 static struct domain localdomain; 106 107 static uma_zone_t unp_zone; 108 static unp_gen_t unp_gencnt; /* (l) */ 109 static u_int unp_count; /* (l) Count of local sockets. */ 110 static ino_t unp_ino; /* Prototype for fake inode numbers. */ 111 static int unp_rights; /* (g) File descriptors in flight. */ 112 static struct unp_head unp_shead; /* (l) List of stream sockets. */ 113 static struct unp_head unp_dhead; /* (l) List of datagram sockets. */ 114 static struct unp_head unp_sphead; /* (l) List of seqpacket sockets. */ 115 116 struct unp_defer { 117 SLIST_ENTRY(unp_defer) ud_link; 118 struct file *ud_fp; 119 }; 120 static SLIST_HEAD(, unp_defer) unp_defers; 121 static int unp_defers_count; 122 123 static const struct sockaddr sun_noname = { 124 .sa_len = sizeof(sun_noname), 125 .sa_family = AF_LOCAL, 126 }; 127 128 /* 129 * Garbage collection of cyclic file descriptor/socket references occurs 130 * asynchronously in a taskqueue context in order to avoid recursion and 131 * reentrance in the UNIX domain socket, file descriptor, and socket layer 132 * code. See unp_gc() for a full description. 133 */ 134 static struct timeout_task unp_gc_task; 135 136 /* 137 * The close of unix domain sockets attached as SCM_RIGHTS is 138 * postponed to the taskqueue, to avoid arbitrary recursion depth. 139 * The attached sockets might have another sockets attached. 140 */ 141 static struct task unp_defer_task; 142 143 /* 144 * Both send and receive buffers are allocated PIPSIZ bytes of buffering for 145 * stream sockets, although the total for sender and receiver is actually 146 * only PIPSIZ. 147 * 148 * Datagram sockets really use the sendspace as the maximum datagram size, 149 * and don't really want to reserve the sendspace. Their recvspace should be 150 * large enough for at least one max-size datagram plus address. 151 */ 152 #ifndef PIPSIZ 153 #define PIPSIZ 8192 154 #endif 155 static u_long unpst_sendspace = PIPSIZ; 156 static u_long unpst_recvspace = PIPSIZ; 157 static u_long unpdg_maxdgram = 8*1024; /* support 8KB syslog msgs */ 158 static u_long unpdg_recvspace = 16*1024; 159 static u_long unpsp_sendspace = PIPSIZ; /* really max datagram size */ 160 static u_long unpsp_recvspace = PIPSIZ; 161 162 static SYSCTL_NODE(_net, PF_LOCAL, local, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 163 "Local domain"); 164 static SYSCTL_NODE(_net_local, SOCK_STREAM, stream, 165 CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 166 "SOCK_STREAM"); 167 static SYSCTL_NODE(_net_local, SOCK_DGRAM, dgram, 168 CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 169 "SOCK_DGRAM"); 170 static SYSCTL_NODE(_net_local, SOCK_SEQPACKET, seqpacket, 171 CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 172 "SOCK_SEQPACKET"); 173 174 SYSCTL_ULONG(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW, 175 &unpst_sendspace, 0, "Default stream send space."); 176 SYSCTL_ULONG(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW, 177 &unpst_recvspace, 0, "Default stream receive space."); 178 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW, 179 &unpdg_maxdgram, 0, "Maximum datagram size."); 180 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW, 181 &unpdg_recvspace, 0, "Default datagram receive space."); 182 SYSCTL_ULONG(_net_local_seqpacket, OID_AUTO, maxseqpacket, CTLFLAG_RW, 183 &unpsp_sendspace, 0, "Default seqpacket send space."); 184 SYSCTL_ULONG(_net_local_seqpacket, OID_AUTO, recvspace, CTLFLAG_RW, 185 &unpsp_recvspace, 0, "Default seqpacket receive space."); 186 SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, 187 "File descriptors in flight."); 188 SYSCTL_INT(_net_local, OID_AUTO, deferred, CTLFLAG_RD, 189 &unp_defers_count, 0, 190 "File descriptors deferred to taskqueue for close."); 191 192 /* 193 * Locking and synchronization: 194 * 195 * Several types of locks exist in the local domain socket implementation: 196 * - a global linkage lock 197 * - a global connection list lock 198 * - the mtxpool lock 199 * - per-unpcb mutexes 200 * 201 * The linkage lock protects the global socket lists, the generation number 202 * counter and garbage collector state. 203 * 204 * The connection list lock protects the list of referring sockets in a datagram 205 * socket PCB. This lock is also overloaded to protect a global list of 206 * sockets whose buffers contain socket references in the form of SCM_RIGHTS 207 * messages. To avoid recursion, such references are released by a dedicated 208 * thread. 209 * 210 * The mtxpool lock protects the vnode from being modified while referenced. 211 * Lock ordering rules require that it be acquired before any PCB locks. 212 * 213 * The unpcb lock (unp_mtx) protects the most commonly referenced fields in the 214 * unpcb. This includes the unp_conn field, which either links two connected 215 * PCBs together (for connected socket types) or points at the destination 216 * socket (for connectionless socket types). The operations of creating or 217 * destroying a connection therefore involve locking multiple PCBs. To avoid 218 * lock order reversals, in some cases this involves dropping a PCB lock and 219 * using a reference counter to maintain liveness. 220 * 221 * UNIX domain sockets each have an unpcb hung off of their so_pcb pointer, 222 * allocated in pr_attach() and freed in pr_detach(). The validity of that 223 * pointer is an invariant, so no lock is required to dereference the so_pcb 224 * pointer if a valid socket reference is held by the caller. In practice, 225 * this is always true during operations performed on a socket. Each unpcb 226 * has a back-pointer to its socket, unp_socket, which will be stable under 227 * the same circumstances. 228 * 229 * This pointer may only be safely dereferenced as long as a valid reference 230 * to the unpcb is held. Typically, this reference will be from the socket, 231 * or from another unpcb when the referring unpcb's lock is held (in order 232 * that the reference not be invalidated during use). For example, to follow 233 * unp->unp_conn->unp_socket, you need to hold a lock on unp_conn to guarantee 234 * that detach is not run clearing unp_socket. 235 * 236 * Blocking with UNIX domain sockets is a tricky issue: unlike most network 237 * protocols, bind() is a non-atomic operation, and connect() requires 238 * potential sleeping in the protocol, due to potentially waiting on local or 239 * distributed file systems. We try to separate "lookup" operations, which 240 * may sleep, and the IPC operations themselves, which typically can occur 241 * with relative atomicity as locks can be held over the entire operation. 242 * 243 * Another tricky issue is simultaneous multi-threaded or multi-process 244 * access to a single UNIX domain socket. These are handled by the flags 245 * UNP_CONNECTING and UNP_BINDING, which prevent concurrent connecting or 246 * binding, both of which involve dropping UNIX domain socket locks in order 247 * to perform namei() and other file system operations. 248 */ 249 static struct rwlock unp_link_rwlock; 250 static struct mtx unp_defers_lock; 251 252 #define UNP_LINK_LOCK_INIT() rw_init(&unp_link_rwlock, \ 253 "unp_link_rwlock") 254 255 #define UNP_LINK_LOCK_ASSERT() rw_assert(&unp_link_rwlock, \ 256 RA_LOCKED) 257 #define UNP_LINK_UNLOCK_ASSERT() rw_assert(&unp_link_rwlock, \ 258 RA_UNLOCKED) 259 260 #define UNP_LINK_RLOCK() rw_rlock(&unp_link_rwlock) 261 #define UNP_LINK_RUNLOCK() rw_runlock(&unp_link_rwlock) 262 #define UNP_LINK_WLOCK() rw_wlock(&unp_link_rwlock) 263 #define UNP_LINK_WUNLOCK() rw_wunlock(&unp_link_rwlock) 264 #define UNP_LINK_WLOCK_ASSERT() rw_assert(&unp_link_rwlock, \ 265 RA_WLOCKED) 266 #define UNP_LINK_WOWNED() rw_wowned(&unp_link_rwlock) 267 268 #define UNP_DEFERRED_LOCK_INIT() mtx_init(&unp_defers_lock, \ 269 "unp_defer", NULL, MTX_DEF) 270 #define UNP_DEFERRED_LOCK() mtx_lock(&unp_defers_lock) 271 #define UNP_DEFERRED_UNLOCK() mtx_unlock(&unp_defers_lock) 272 273 #define UNP_REF_LIST_LOCK() UNP_DEFERRED_LOCK(); 274 #define UNP_REF_LIST_UNLOCK() UNP_DEFERRED_UNLOCK(); 275 276 #define UNP_PCB_LOCK_INIT(unp) mtx_init(&(unp)->unp_mtx, \ 277 "unp", "unp", \ 278 MTX_DUPOK|MTX_DEF) 279 #define UNP_PCB_LOCK_DESTROY(unp) mtx_destroy(&(unp)->unp_mtx) 280 #define UNP_PCB_LOCKPTR(unp) (&(unp)->unp_mtx) 281 #define UNP_PCB_LOCK(unp) mtx_lock(&(unp)->unp_mtx) 282 #define UNP_PCB_TRYLOCK(unp) mtx_trylock(&(unp)->unp_mtx) 283 #define UNP_PCB_UNLOCK(unp) mtx_unlock(&(unp)->unp_mtx) 284 #define UNP_PCB_OWNED(unp) mtx_owned(&(unp)->unp_mtx) 285 #define UNP_PCB_LOCK_ASSERT(unp) mtx_assert(&(unp)->unp_mtx, MA_OWNED) 286 #define UNP_PCB_UNLOCK_ASSERT(unp) mtx_assert(&(unp)->unp_mtx, MA_NOTOWNED) 287 288 static int uipc_connect2(struct socket *, struct socket *); 289 static int uipc_ctloutput(struct socket *, struct sockopt *); 290 static int unp_connect(struct socket *, struct sockaddr *, 291 struct thread *); 292 static int unp_connectat(int, struct socket *, struct sockaddr *, 293 struct thread *, bool); 294 static void unp_connect2(struct socket *so, struct socket *so2); 295 static void unp_disconnect(struct unpcb *unp, struct unpcb *unp2); 296 static void unp_dispose(struct socket *so); 297 static void unp_shutdown(struct unpcb *); 298 static void unp_drop(struct unpcb *); 299 static void unp_gc(__unused void *, int); 300 static void unp_scan(struct mbuf *, void (*)(struct filedescent **, int)); 301 static void unp_discard(struct file *); 302 static void unp_freerights(struct filedescent **, int); 303 static int unp_internalize(struct mbuf **, struct thread *, 304 struct mbuf **, u_int *, u_int *); 305 static void unp_internalize_fp(struct file *); 306 static int unp_externalize(struct mbuf *, struct mbuf **, int); 307 static int unp_externalize_fp(struct file *); 308 static struct mbuf *unp_addsockcred(struct thread *, struct mbuf *, 309 int, struct mbuf **, u_int *, u_int *); 310 static void unp_process_defers(void * __unused, int); 311 312 static void 313 unp_pcb_hold(struct unpcb *unp) 314 { 315 u_int old __unused; 316 317 old = refcount_acquire(&unp->unp_refcount); 318 KASSERT(old > 0, ("%s: unpcb %p has no references", __func__, unp)); 319 } 320 321 static __result_use_check bool 322 unp_pcb_rele(struct unpcb *unp) 323 { 324 bool ret; 325 326 UNP_PCB_LOCK_ASSERT(unp); 327 328 if ((ret = refcount_release(&unp->unp_refcount))) { 329 UNP_PCB_UNLOCK(unp); 330 UNP_PCB_LOCK_DESTROY(unp); 331 uma_zfree(unp_zone, unp); 332 } 333 return (ret); 334 } 335 336 static void 337 unp_pcb_rele_notlast(struct unpcb *unp) 338 { 339 bool ret __unused; 340 341 ret = refcount_release(&unp->unp_refcount); 342 KASSERT(!ret, ("%s: unpcb %p has no references", __func__, unp)); 343 } 344 345 static void 346 unp_pcb_lock_pair(struct unpcb *unp, struct unpcb *unp2) 347 { 348 UNP_PCB_UNLOCK_ASSERT(unp); 349 UNP_PCB_UNLOCK_ASSERT(unp2); 350 351 if (unp == unp2) { 352 UNP_PCB_LOCK(unp); 353 } else if ((uintptr_t)unp2 > (uintptr_t)unp) { 354 UNP_PCB_LOCK(unp); 355 UNP_PCB_LOCK(unp2); 356 } else { 357 UNP_PCB_LOCK(unp2); 358 UNP_PCB_LOCK(unp); 359 } 360 } 361 362 static void 363 unp_pcb_unlock_pair(struct unpcb *unp, struct unpcb *unp2) 364 { 365 UNP_PCB_UNLOCK(unp); 366 if (unp != unp2) 367 UNP_PCB_UNLOCK(unp2); 368 } 369 370 /* 371 * Try to lock the connected peer of an already locked socket. In some cases 372 * this requires that we unlock the current socket. The pairbusy counter is 373 * used to block concurrent connection attempts while the lock is dropped. The 374 * caller must be careful to revalidate PCB state. 375 */ 376 static struct unpcb * 377 unp_pcb_lock_peer(struct unpcb *unp) 378 { 379 struct unpcb *unp2; 380 381 UNP_PCB_LOCK_ASSERT(unp); 382 unp2 = unp->unp_conn; 383 if (unp2 == NULL) 384 return (NULL); 385 if (__predict_false(unp == unp2)) 386 return (unp); 387 388 UNP_PCB_UNLOCK_ASSERT(unp2); 389 390 if (__predict_true(UNP_PCB_TRYLOCK(unp2))) 391 return (unp2); 392 if ((uintptr_t)unp2 > (uintptr_t)unp) { 393 UNP_PCB_LOCK(unp2); 394 return (unp2); 395 } 396 unp->unp_pairbusy++; 397 unp_pcb_hold(unp2); 398 UNP_PCB_UNLOCK(unp); 399 400 UNP_PCB_LOCK(unp2); 401 UNP_PCB_LOCK(unp); 402 KASSERT(unp->unp_conn == unp2 || unp->unp_conn == NULL, 403 ("%s: socket %p was reconnected", __func__, unp)); 404 if (--unp->unp_pairbusy == 0 && (unp->unp_flags & UNP_WAITING) != 0) { 405 unp->unp_flags &= ~UNP_WAITING; 406 wakeup(unp); 407 } 408 if (unp_pcb_rele(unp2)) { 409 /* unp2 is unlocked. */ 410 return (NULL); 411 } 412 if (unp->unp_conn == NULL) { 413 UNP_PCB_UNLOCK(unp2); 414 return (NULL); 415 } 416 return (unp2); 417 } 418 419 static void 420 uipc_abort(struct socket *so) 421 { 422 struct unpcb *unp, *unp2; 423 424 unp = sotounpcb(so); 425 KASSERT(unp != NULL, ("uipc_abort: unp == NULL")); 426 UNP_PCB_UNLOCK_ASSERT(unp); 427 428 UNP_PCB_LOCK(unp); 429 unp2 = unp->unp_conn; 430 if (unp2 != NULL) { 431 unp_pcb_hold(unp2); 432 UNP_PCB_UNLOCK(unp); 433 unp_drop(unp2); 434 } else 435 UNP_PCB_UNLOCK(unp); 436 } 437 438 static int 439 uipc_attach(struct socket *so, int proto, struct thread *td) 440 { 441 u_long sendspace, recvspace; 442 struct unpcb *unp; 443 int error; 444 bool locked; 445 446 KASSERT(so->so_pcb == NULL, ("uipc_attach: so_pcb != NULL")); 447 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 448 switch (so->so_type) { 449 case SOCK_STREAM: 450 sendspace = unpst_sendspace; 451 recvspace = unpst_recvspace; 452 break; 453 454 case SOCK_DGRAM: 455 STAILQ_INIT(&so->so_rcv.uxdg_mb); 456 STAILQ_INIT(&so->so_snd.uxdg_mb); 457 TAILQ_INIT(&so->so_rcv.uxdg_conns); 458 /* 459 * Since send buffer is either bypassed or is a part 460 * of one-to-many receive buffer, we assign both space 461 * limits to unpdg_recvspace. 462 */ 463 sendspace = recvspace = unpdg_recvspace; 464 break; 465 466 case SOCK_SEQPACKET: 467 sendspace = unpsp_sendspace; 468 recvspace = unpsp_recvspace; 469 break; 470 471 default: 472 panic("uipc_attach"); 473 } 474 error = soreserve(so, sendspace, recvspace); 475 if (error) 476 return (error); 477 } 478 unp = uma_zalloc(unp_zone, M_NOWAIT | M_ZERO); 479 if (unp == NULL) 480 return (ENOBUFS); 481 LIST_INIT(&unp->unp_refs); 482 UNP_PCB_LOCK_INIT(unp); 483 unp->unp_socket = so; 484 so->so_pcb = unp; 485 refcount_init(&unp->unp_refcount, 1); 486 487 if ((locked = UNP_LINK_WOWNED()) == false) 488 UNP_LINK_WLOCK(); 489 490 unp->unp_gencnt = ++unp_gencnt; 491 unp->unp_ino = ++unp_ino; 492 unp_count++; 493 switch (so->so_type) { 494 case SOCK_STREAM: 495 LIST_INSERT_HEAD(&unp_shead, unp, unp_link); 496 break; 497 498 case SOCK_DGRAM: 499 LIST_INSERT_HEAD(&unp_dhead, unp, unp_link); 500 break; 501 502 case SOCK_SEQPACKET: 503 LIST_INSERT_HEAD(&unp_sphead, unp, unp_link); 504 break; 505 506 default: 507 panic("uipc_attach"); 508 } 509 510 if (locked == false) 511 UNP_LINK_WUNLOCK(); 512 513 return (0); 514 } 515 516 static int 517 uipc_bindat(int fd, struct socket *so, struct sockaddr *nam, struct thread *td) 518 { 519 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 520 struct vattr vattr; 521 int error, namelen; 522 struct nameidata nd; 523 struct unpcb *unp; 524 struct vnode *vp; 525 struct mount *mp; 526 cap_rights_t rights; 527 char *buf; 528 529 if (nam->sa_family != AF_UNIX) 530 return (EAFNOSUPPORT); 531 532 unp = sotounpcb(so); 533 KASSERT(unp != NULL, ("uipc_bind: unp == NULL")); 534 535 if (soun->sun_len > sizeof(struct sockaddr_un)) 536 return (EINVAL); 537 namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path); 538 if (namelen <= 0) 539 return (EINVAL); 540 541 /* 542 * We don't allow simultaneous bind() calls on a single UNIX domain 543 * socket, so flag in-progress operations, and return an error if an 544 * operation is already in progress. 545 * 546 * Historically, we have not allowed a socket to be rebound, so this 547 * also returns an error. Not allowing re-binding simplifies the 548 * implementation and avoids a great many possible failure modes. 549 */ 550 UNP_PCB_LOCK(unp); 551 if (unp->unp_vnode != NULL) { 552 UNP_PCB_UNLOCK(unp); 553 return (EINVAL); 554 } 555 if (unp->unp_flags & UNP_BINDING) { 556 UNP_PCB_UNLOCK(unp); 557 return (EALREADY); 558 } 559 unp->unp_flags |= UNP_BINDING; 560 UNP_PCB_UNLOCK(unp); 561 562 buf = malloc(namelen + 1, M_TEMP, M_WAITOK); 563 bcopy(soun->sun_path, buf, namelen); 564 buf[namelen] = 0; 565 566 restart: 567 NDINIT_ATRIGHTS(&nd, CREATE, NOFOLLOW | LOCKPARENT | NOCACHE, 568 UIO_SYSSPACE, buf, fd, cap_rights_init_one(&rights, CAP_BINDAT)); 569 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ 570 error = namei(&nd); 571 if (error) 572 goto error; 573 vp = nd.ni_vp; 574 if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) { 575 NDFREE_PNBUF(&nd); 576 if (nd.ni_dvp == vp) 577 vrele(nd.ni_dvp); 578 else 579 vput(nd.ni_dvp); 580 if (vp != NULL) { 581 vrele(vp); 582 error = EADDRINUSE; 583 goto error; 584 } 585 error = vn_start_write(NULL, &mp, V_XSLEEP | V_PCATCH); 586 if (error) 587 goto error; 588 goto restart; 589 } 590 VATTR_NULL(&vattr); 591 vattr.va_type = VSOCK; 592 vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_pd->pd_cmask); 593 #ifdef MAC 594 error = mac_vnode_check_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd, 595 &vattr); 596 #endif 597 if (error == 0) { 598 /* 599 * The prior lookup may have left LK_SHARED in cn_lkflags, 600 * and VOP_CREATE technically only requires the new vnode to 601 * be locked shared. Most filesystems will return the new vnode 602 * locked exclusive regardless, but we should explicitly 603 * specify that here since we require it and assert to that 604 * effect below. 605 */ 606 nd.ni_cnd.cn_lkflags = (nd.ni_cnd.cn_lkflags & ~LK_SHARED) | 607 LK_EXCLUSIVE; 608 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); 609 } 610 NDFREE_PNBUF(&nd); 611 if (error) { 612 VOP_VPUT_PAIR(nd.ni_dvp, NULL, true); 613 vn_finished_write(mp); 614 if (error == ERELOOKUP) 615 goto restart; 616 goto error; 617 } 618 vp = nd.ni_vp; 619 ASSERT_VOP_ELOCKED(vp, "uipc_bind"); 620 soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK); 621 622 UNP_PCB_LOCK(unp); 623 VOP_UNP_BIND(vp, unp); 624 unp->unp_vnode = vp; 625 unp->unp_addr = soun; 626 unp->unp_flags &= ~UNP_BINDING; 627 UNP_PCB_UNLOCK(unp); 628 vref(vp); 629 VOP_VPUT_PAIR(nd.ni_dvp, &vp, true); 630 vn_finished_write(mp); 631 free(buf, M_TEMP); 632 return (0); 633 634 error: 635 UNP_PCB_LOCK(unp); 636 unp->unp_flags &= ~UNP_BINDING; 637 UNP_PCB_UNLOCK(unp); 638 free(buf, M_TEMP); 639 return (error); 640 } 641 642 static int 643 uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 644 { 645 646 return (uipc_bindat(AT_FDCWD, so, nam, td)); 647 } 648 649 static int 650 uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 651 { 652 int error; 653 654 KASSERT(td == curthread, ("uipc_connect: td != curthread")); 655 error = unp_connect(so, nam, td); 656 return (error); 657 } 658 659 static int 660 uipc_connectat(int fd, struct socket *so, struct sockaddr *nam, 661 struct thread *td) 662 { 663 int error; 664 665 KASSERT(td == curthread, ("uipc_connectat: td != curthread")); 666 error = unp_connectat(fd, so, nam, td, false); 667 return (error); 668 } 669 670 static void 671 uipc_close(struct socket *so) 672 { 673 struct unpcb *unp, *unp2; 674 struct vnode *vp = NULL; 675 struct mtx *vplock; 676 677 unp = sotounpcb(so); 678 KASSERT(unp != NULL, ("uipc_close: unp == NULL")); 679 680 vplock = NULL; 681 if ((vp = unp->unp_vnode) != NULL) { 682 vplock = mtx_pool_find(mtxpool_sleep, vp); 683 mtx_lock(vplock); 684 } 685 UNP_PCB_LOCK(unp); 686 if (vp && unp->unp_vnode == NULL) { 687 mtx_unlock(vplock); 688 vp = NULL; 689 } 690 if (vp != NULL) { 691 VOP_UNP_DETACH(vp); 692 unp->unp_vnode = NULL; 693 } 694 if ((unp2 = unp_pcb_lock_peer(unp)) != NULL) 695 unp_disconnect(unp, unp2); 696 else 697 UNP_PCB_UNLOCK(unp); 698 if (vp) { 699 mtx_unlock(vplock); 700 vrele(vp); 701 } 702 } 703 704 static int 705 uipc_connect2(struct socket *so1, struct socket *so2) 706 { 707 struct unpcb *unp, *unp2; 708 709 if (so1->so_type != so2->so_type) 710 return (EPROTOTYPE); 711 712 unp = so1->so_pcb; 713 KASSERT(unp != NULL, ("uipc_connect2: unp == NULL")); 714 unp2 = so2->so_pcb; 715 KASSERT(unp2 != NULL, ("uipc_connect2: unp2 == NULL")); 716 unp_pcb_lock_pair(unp, unp2); 717 unp_connect2(so1, so2); 718 unp_pcb_unlock_pair(unp, unp2); 719 720 return (0); 721 } 722 723 static void 724 uipc_detach(struct socket *so) 725 { 726 struct unpcb *unp, *unp2; 727 struct mtx *vplock; 728 struct vnode *vp; 729 int local_unp_rights; 730 731 unp = sotounpcb(so); 732 KASSERT(unp != NULL, ("uipc_detach: unp == NULL")); 733 734 vp = NULL; 735 vplock = NULL; 736 737 if (!SOLISTENING(so)) 738 unp_dispose(so); 739 740 UNP_LINK_WLOCK(); 741 LIST_REMOVE(unp, unp_link); 742 if (unp->unp_gcflag & UNPGC_DEAD) 743 LIST_REMOVE(unp, unp_dead); 744 unp->unp_gencnt = ++unp_gencnt; 745 --unp_count; 746 UNP_LINK_WUNLOCK(); 747 748 UNP_PCB_UNLOCK_ASSERT(unp); 749 restart: 750 if ((vp = unp->unp_vnode) != NULL) { 751 vplock = mtx_pool_find(mtxpool_sleep, vp); 752 mtx_lock(vplock); 753 } 754 UNP_PCB_LOCK(unp); 755 if (unp->unp_vnode != vp && unp->unp_vnode != NULL) { 756 if (vplock) 757 mtx_unlock(vplock); 758 UNP_PCB_UNLOCK(unp); 759 goto restart; 760 } 761 if ((vp = unp->unp_vnode) != NULL) { 762 VOP_UNP_DETACH(vp); 763 unp->unp_vnode = NULL; 764 } 765 if ((unp2 = unp_pcb_lock_peer(unp)) != NULL) 766 unp_disconnect(unp, unp2); 767 else 768 UNP_PCB_UNLOCK(unp); 769 770 UNP_REF_LIST_LOCK(); 771 while (!LIST_EMPTY(&unp->unp_refs)) { 772 struct unpcb *ref = LIST_FIRST(&unp->unp_refs); 773 774 unp_pcb_hold(ref); 775 UNP_REF_LIST_UNLOCK(); 776 777 MPASS(ref != unp); 778 UNP_PCB_UNLOCK_ASSERT(ref); 779 unp_drop(ref); 780 UNP_REF_LIST_LOCK(); 781 } 782 UNP_REF_LIST_UNLOCK(); 783 784 UNP_PCB_LOCK(unp); 785 local_unp_rights = unp_rights; 786 unp->unp_socket->so_pcb = NULL; 787 unp->unp_socket = NULL; 788 free(unp->unp_addr, M_SONAME); 789 unp->unp_addr = NULL; 790 if (!unp_pcb_rele(unp)) 791 UNP_PCB_UNLOCK(unp); 792 if (vp) { 793 mtx_unlock(vplock); 794 vrele(vp); 795 } 796 if (local_unp_rights) 797 taskqueue_enqueue_timeout(taskqueue_thread, &unp_gc_task, -1); 798 799 switch (so->so_type) { 800 case SOCK_DGRAM: 801 /* 802 * Everything should have been unlinked/freed by unp_dispose() 803 * and/or unp_disconnect(). 804 */ 805 MPASS(so->so_rcv.uxdg_peeked == NULL); 806 MPASS(STAILQ_EMPTY(&so->so_rcv.uxdg_mb)); 807 MPASS(TAILQ_EMPTY(&so->so_rcv.uxdg_conns)); 808 MPASS(STAILQ_EMPTY(&so->so_snd.uxdg_mb)); 809 } 810 } 811 812 static int 813 uipc_disconnect(struct socket *so) 814 { 815 struct unpcb *unp, *unp2; 816 817 unp = sotounpcb(so); 818 KASSERT(unp != NULL, ("uipc_disconnect: unp == NULL")); 819 820 UNP_PCB_LOCK(unp); 821 if ((unp2 = unp_pcb_lock_peer(unp)) != NULL) 822 unp_disconnect(unp, unp2); 823 else 824 UNP_PCB_UNLOCK(unp); 825 return (0); 826 } 827 828 static int 829 uipc_listen(struct socket *so, int backlog, struct thread *td) 830 { 831 struct unpcb *unp; 832 int error; 833 834 MPASS(so->so_type != SOCK_DGRAM); 835 836 /* 837 * Synchronize with concurrent connection attempts. 838 */ 839 error = 0; 840 unp = sotounpcb(so); 841 UNP_PCB_LOCK(unp); 842 if (unp->unp_conn != NULL || (unp->unp_flags & UNP_CONNECTING) != 0) 843 error = EINVAL; 844 else if (unp->unp_vnode == NULL) 845 error = EDESTADDRREQ; 846 if (error != 0) { 847 UNP_PCB_UNLOCK(unp); 848 return (error); 849 } 850 851 SOCK_LOCK(so); 852 error = solisten_proto_check(so); 853 if (error == 0) { 854 cru2xt(td, &unp->unp_peercred); 855 solisten_proto(so, backlog); 856 } 857 SOCK_UNLOCK(so); 858 UNP_PCB_UNLOCK(unp); 859 return (error); 860 } 861 862 static int 863 uipc_peeraddr(struct socket *so, struct sockaddr *ret) 864 { 865 struct unpcb *unp, *unp2; 866 const struct sockaddr *sa; 867 868 unp = sotounpcb(so); 869 KASSERT(unp != NULL, ("uipc_peeraddr: unp == NULL")); 870 871 UNP_PCB_LOCK(unp); 872 unp2 = unp_pcb_lock_peer(unp); 873 if (unp2 != NULL) { 874 if (unp2->unp_addr != NULL) 875 sa = (struct sockaddr *)unp2->unp_addr; 876 else 877 sa = &sun_noname; 878 bcopy(sa, ret, sa->sa_len); 879 unp_pcb_unlock_pair(unp, unp2); 880 } else { 881 UNP_PCB_UNLOCK(unp); 882 sa = &sun_noname; 883 bcopy(sa, ret, sa->sa_len); 884 } 885 return (0); 886 } 887 888 static int 889 uipc_rcvd(struct socket *so, int flags) 890 { 891 struct unpcb *unp, *unp2; 892 struct socket *so2; 893 u_int mbcnt, sbcc; 894 895 unp = sotounpcb(so); 896 KASSERT(unp != NULL, ("%s: unp == NULL", __func__)); 897 KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET, 898 ("%s: socktype %d", __func__, so->so_type)); 899 900 /* 901 * Adjust backpressure on sender and wakeup any waiting to write. 902 * 903 * The unp lock is acquired to maintain the validity of the unp_conn 904 * pointer; no lock on unp2 is required as unp2->unp_socket will be 905 * static as long as we don't permit unp2 to disconnect from unp, 906 * which is prevented by the lock on unp. We cache values from 907 * so_rcv to avoid holding the so_rcv lock over the entire 908 * transaction on the remote so_snd. 909 */ 910 SOCKBUF_LOCK(&so->so_rcv); 911 mbcnt = so->so_rcv.sb_mbcnt; 912 sbcc = sbavail(&so->so_rcv); 913 SOCKBUF_UNLOCK(&so->so_rcv); 914 /* 915 * There is a benign race condition at this point. If we're planning to 916 * clear SB_STOP, but uipc_send is called on the connected socket at 917 * this instant, it might add data to the sockbuf and set SB_STOP. Then 918 * we would erroneously clear SB_STOP below, even though the sockbuf is 919 * full. The race is benign because the only ill effect is to allow the 920 * sockbuf to exceed its size limit, and the size limits are not 921 * strictly guaranteed anyway. 922 */ 923 UNP_PCB_LOCK(unp); 924 unp2 = unp->unp_conn; 925 if (unp2 == NULL) { 926 UNP_PCB_UNLOCK(unp); 927 return (0); 928 } 929 so2 = unp2->unp_socket; 930 SOCKBUF_LOCK(&so2->so_snd); 931 if (sbcc < so2->so_snd.sb_hiwat && mbcnt < so2->so_snd.sb_mbmax) 932 so2->so_snd.sb_flags &= ~SB_STOP; 933 sowwakeup_locked(so2); 934 UNP_PCB_UNLOCK(unp); 935 return (0); 936 } 937 938 static int 939 uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 940 struct mbuf *control, struct thread *td) 941 { 942 struct unpcb *unp, *unp2; 943 struct socket *so2; 944 u_int mbcnt, sbcc; 945 int error; 946 947 unp = sotounpcb(so); 948 KASSERT(unp != NULL, ("%s: unp == NULL", __func__)); 949 KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET, 950 ("%s: socktype %d", __func__, so->so_type)); 951 952 error = 0; 953 if (flags & PRUS_OOB) { 954 error = EOPNOTSUPP; 955 goto release; 956 } 957 if (control != NULL && 958 (error = unp_internalize(&control, td, NULL, NULL, NULL))) 959 goto release; 960 961 unp2 = NULL; 962 if ((so->so_state & SS_ISCONNECTED) == 0) { 963 if (nam != NULL) { 964 if ((error = unp_connect(so, nam, td)) != 0) 965 goto out; 966 } else { 967 error = ENOTCONN; 968 goto out; 969 } 970 } 971 972 UNP_PCB_LOCK(unp); 973 if ((unp2 = unp_pcb_lock_peer(unp)) == NULL) { 974 UNP_PCB_UNLOCK(unp); 975 error = ENOTCONN; 976 goto out; 977 } else if (so->so_snd.sb_state & SBS_CANTSENDMORE) { 978 unp_pcb_unlock_pair(unp, unp2); 979 error = EPIPE; 980 goto out; 981 } 982 UNP_PCB_UNLOCK(unp); 983 if ((so2 = unp2->unp_socket) == NULL) { 984 UNP_PCB_UNLOCK(unp2); 985 error = ENOTCONN; 986 goto out; 987 } 988 SOCKBUF_LOCK(&so2->so_rcv); 989 if (unp2->unp_flags & UNP_WANTCRED_MASK) { 990 /* 991 * Credentials are passed only once on SOCK_STREAM and 992 * SOCK_SEQPACKET (LOCAL_CREDS => WANTCRED_ONESHOT), or 993 * forever (LOCAL_CREDS_PERSISTENT => WANTCRED_ALWAYS). 994 */ 995 control = unp_addsockcred(td, control, unp2->unp_flags, NULL, 996 NULL, NULL); 997 unp2->unp_flags &= ~UNP_WANTCRED_ONESHOT; 998 } 999 1000 /* 1001 * Send to paired receive port and wake up readers. Don't 1002 * check for space available in the receive buffer if we're 1003 * attaching ancillary data; Unix domain sockets only check 1004 * for space in the sending sockbuf, and that check is 1005 * performed one level up the stack. At that level we cannot 1006 * precisely account for the amount of buffer space used 1007 * (e.g., because control messages are not yet internalized). 1008 */ 1009 switch (so->so_type) { 1010 case SOCK_STREAM: 1011 if (control != NULL) { 1012 sbappendcontrol_locked(&so2->so_rcv, 1013 m->m_len > 0 ? m : NULL, control, flags); 1014 control = NULL; 1015 } else 1016 sbappend_locked(&so2->so_rcv, m, flags); 1017 break; 1018 1019 case SOCK_SEQPACKET: 1020 if (sbappendaddr_nospacecheck_locked(&so2->so_rcv, 1021 &sun_noname, m, control)) 1022 control = NULL; 1023 break; 1024 } 1025 1026 mbcnt = so2->so_rcv.sb_mbcnt; 1027 sbcc = sbavail(&so2->so_rcv); 1028 if (sbcc) 1029 sorwakeup_locked(so2); 1030 else 1031 SOCKBUF_UNLOCK(&so2->so_rcv); 1032 1033 /* 1034 * The PCB lock on unp2 protects the SB_STOP flag. Without it, 1035 * it would be possible for uipc_rcvd to be called at this 1036 * point, drain the receiving sockbuf, clear SB_STOP, and then 1037 * we would set SB_STOP below. That could lead to an empty 1038 * sockbuf having SB_STOP set 1039 */ 1040 SOCKBUF_LOCK(&so->so_snd); 1041 if (sbcc >= so->so_snd.sb_hiwat || mbcnt >= so->so_snd.sb_mbmax) 1042 so->so_snd.sb_flags |= SB_STOP; 1043 SOCKBUF_UNLOCK(&so->so_snd); 1044 UNP_PCB_UNLOCK(unp2); 1045 m = NULL; 1046 out: 1047 /* 1048 * PRUS_EOF is equivalent to pr_send followed by pr_shutdown. 1049 */ 1050 if (flags & PRUS_EOF) { 1051 UNP_PCB_LOCK(unp); 1052 socantsendmore(so); 1053 unp_shutdown(unp); 1054 UNP_PCB_UNLOCK(unp); 1055 } 1056 if (control != NULL && error != 0) 1057 unp_scan(control, unp_freerights); 1058 1059 release: 1060 if (control != NULL) 1061 m_freem(control); 1062 /* 1063 * In case of PRUS_NOTREADY, uipc_ready() is responsible 1064 * for freeing memory. 1065 */ 1066 if (m != NULL && (flags & PRUS_NOTREADY) == 0) 1067 m_freem(m); 1068 return (error); 1069 } 1070 1071 /* PF_UNIX/SOCK_DGRAM version of sbspace() */ 1072 static inline bool 1073 uipc_dgram_sbspace(struct sockbuf *sb, u_int cc, u_int mbcnt) 1074 { 1075 u_int bleft, mleft; 1076 1077 /* 1078 * Negative space may happen if send(2) is followed by 1079 * setsockopt(SO_SNDBUF/SO_RCVBUF) that shrinks maximum. 1080 */ 1081 if (__predict_false(sb->sb_hiwat < sb->uxdg_cc || 1082 sb->sb_mbmax < sb->uxdg_mbcnt)) 1083 return (false); 1084 1085 if (__predict_false(sb->sb_state & SBS_CANTRCVMORE)) 1086 return (false); 1087 1088 bleft = sb->sb_hiwat - sb->uxdg_cc; 1089 mleft = sb->sb_mbmax - sb->uxdg_mbcnt; 1090 1091 return (bleft >= cc && mleft >= mbcnt); 1092 } 1093 1094 /* 1095 * PF_UNIX/SOCK_DGRAM send 1096 * 1097 * Allocate a record consisting of 3 mbufs in the sequence of 1098 * from -> control -> data and append it to the socket buffer. 1099 * 1100 * The first mbuf carries sender's name and is a pkthdr that stores 1101 * overall length of datagram, its memory consumption and control length. 1102 */ 1103 #define ctllen PH_loc.thirtytwo[1] 1104 _Static_assert(offsetof(struct pkthdr, memlen) + sizeof(u_int) <= 1105 offsetof(struct pkthdr, ctllen), "unix/dgram can not store ctllen"); 1106 static int 1107 uipc_sosend_dgram(struct socket *so, struct sockaddr *addr, struct uio *uio, 1108 struct mbuf *m, struct mbuf *c, int flags, struct thread *td) 1109 { 1110 struct unpcb *unp, *unp2; 1111 const struct sockaddr *from; 1112 struct socket *so2; 1113 struct sockbuf *sb; 1114 struct mbuf *f, *clast; 1115 u_int cc, ctl, mbcnt; 1116 u_int dcc __diagused, dctl __diagused, dmbcnt __diagused; 1117 int error; 1118 1119 MPASS((uio != NULL && m == NULL) || (m != NULL && uio == NULL)); 1120 1121 error = 0; 1122 f = NULL; 1123 ctl = 0; 1124 1125 if (__predict_false(flags & MSG_OOB)) { 1126 error = EOPNOTSUPP; 1127 goto out; 1128 } 1129 if (m == NULL) { 1130 if (__predict_false(uio->uio_resid > unpdg_maxdgram)) { 1131 error = EMSGSIZE; 1132 goto out; 1133 } 1134 m = m_uiotombuf(uio, M_WAITOK, 0, max_hdr, M_PKTHDR); 1135 if (__predict_false(m == NULL)) { 1136 error = EFAULT; 1137 goto out; 1138 } 1139 f = m_gethdr(M_WAITOK, MT_SONAME); 1140 cc = m->m_pkthdr.len; 1141 mbcnt = MSIZE + m->m_pkthdr.memlen; 1142 if (c != NULL && 1143 (error = unp_internalize(&c, td, &clast, &ctl, &mbcnt))) 1144 goto out; 1145 } else { 1146 /* pr_sosend() with mbuf usually is a kernel thread. */ 1147 1148 M_ASSERTPKTHDR(m); 1149 if (__predict_false(c != NULL)) 1150 panic("%s: control from a kernel thread", __func__); 1151 1152 if (__predict_false(m->m_pkthdr.len > unpdg_maxdgram)) { 1153 error = EMSGSIZE; 1154 goto out; 1155 } 1156 if ((f = m_gethdr(M_NOWAIT, MT_SONAME)) == NULL) { 1157 error = ENOBUFS; 1158 goto out; 1159 } 1160 /* Condition the foreign mbuf to our standards. */ 1161 m_clrprotoflags(m); 1162 m_tag_delete_chain(m, NULL); 1163 m->m_pkthdr.rcvif = NULL; 1164 m->m_pkthdr.flowid = 0; 1165 m->m_pkthdr.csum_flags = 0; 1166 m->m_pkthdr.fibnum = 0; 1167 m->m_pkthdr.rsstype = 0; 1168 1169 cc = m->m_pkthdr.len; 1170 mbcnt = MSIZE; 1171 for (struct mbuf *mb = m; mb != NULL; mb = mb->m_next) { 1172 mbcnt += MSIZE; 1173 if (mb->m_flags & M_EXT) 1174 mbcnt += mb->m_ext.ext_size; 1175 } 1176 } 1177 1178 unp = sotounpcb(so); 1179 MPASS(unp); 1180 1181 /* 1182 * XXXGL: would be cool to fully remove so_snd out of the equation 1183 * and avoid this lock, which is not only extraneous, but also being 1184 * released, thus still leaving possibility for a race. We can easily 1185 * handle SBS_CANTSENDMORE/SS_ISCONNECTED complement in unpcb, but it 1186 * is more difficult to invent something to handle so_error. 1187 */ 1188 error = SOCK_IO_SEND_LOCK(so, SBLOCKWAIT(flags)); 1189 if (error) 1190 goto out2; 1191 SOCK_SENDBUF_LOCK(so); 1192 if (so->so_snd.sb_state & SBS_CANTSENDMORE) { 1193 SOCK_SENDBUF_UNLOCK(so); 1194 error = EPIPE; 1195 goto out3; 1196 } 1197 if (so->so_error != 0) { 1198 error = so->so_error; 1199 so->so_error = 0; 1200 SOCK_SENDBUF_UNLOCK(so); 1201 goto out3; 1202 } 1203 if (((so->so_state & SS_ISCONNECTED) == 0) && addr == NULL) { 1204 SOCK_SENDBUF_UNLOCK(so); 1205 error = EDESTADDRREQ; 1206 goto out3; 1207 } 1208 SOCK_SENDBUF_UNLOCK(so); 1209 1210 if (addr != NULL) { 1211 if ((error = unp_connectat(AT_FDCWD, so, addr, td, true))) 1212 goto out3; 1213 UNP_PCB_LOCK_ASSERT(unp); 1214 unp2 = unp->unp_conn; 1215 UNP_PCB_LOCK_ASSERT(unp2); 1216 } else { 1217 UNP_PCB_LOCK(unp); 1218 unp2 = unp_pcb_lock_peer(unp); 1219 if (unp2 == NULL) { 1220 UNP_PCB_UNLOCK(unp); 1221 error = ENOTCONN; 1222 goto out3; 1223 } 1224 } 1225 1226 if (unp2->unp_flags & UNP_WANTCRED_MASK) 1227 c = unp_addsockcred(td, c, unp2->unp_flags, &clast, &ctl, 1228 &mbcnt); 1229 if (unp->unp_addr != NULL) 1230 from = (struct sockaddr *)unp->unp_addr; 1231 else 1232 from = &sun_noname; 1233 f->m_len = from->sa_len; 1234 MPASS(from->sa_len <= MLEN); 1235 bcopy(from, mtod(f, void *), from->sa_len); 1236 ctl += f->m_len; 1237 1238 /* 1239 * Concatenate mbufs: from -> control -> data. 1240 * Save overall cc and mbcnt in "from" mbuf. 1241 */ 1242 if (c != NULL) { 1243 #ifdef INVARIANTS 1244 struct mbuf *mc; 1245 1246 for (mc = c; mc->m_next != NULL; mc = mc->m_next); 1247 MPASS(mc == clast); 1248 #endif 1249 f->m_next = c; 1250 clast->m_next = m; 1251 c = NULL; 1252 } else 1253 f->m_next = m; 1254 m = NULL; 1255 #ifdef INVARIANTS 1256 dcc = dctl = dmbcnt = 0; 1257 for (struct mbuf *mb = f; mb != NULL; mb = mb->m_next) { 1258 if (mb->m_type == MT_DATA) 1259 dcc += mb->m_len; 1260 else 1261 dctl += mb->m_len; 1262 dmbcnt += MSIZE; 1263 if (mb->m_flags & M_EXT) 1264 dmbcnt += mb->m_ext.ext_size; 1265 } 1266 MPASS(dcc == cc); 1267 MPASS(dctl == ctl); 1268 MPASS(dmbcnt == mbcnt); 1269 #endif 1270 f->m_pkthdr.len = cc + ctl; 1271 f->m_pkthdr.memlen = mbcnt; 1272 f->m_pkthdr.ctllen = ctl; 1273 1274 /* 1275 * Destination socket buffer selection. 1276 * 1277 * Unconnected sends, when !(so->so_state & SS_ISCONNECTED) and the 1278 * destination address is supplied, create a temporary connection for 1279 * the run time of the function (see call to unp_connectat() above and 1280 * to unp_disconnect() below). We distinguish them by condition of 1281 * (addr != NULL). We intentionally avoid adding 'bool connected' for 1282 * that condition, since, again, through the run time of this code we 1283 * are always connected. For such "unconnected" sends, the destination 1284 * buffer would be the receive buffer of destination socket so2. 1285 * 1286 * For connected sends, data lands on the send buffer of the sender's 1287 * socket "so". Then, if we just added the very first datagram 1288 * on this send buffer, we need to add the send buffer on to the 1289 * receiving socket's buffer list. We put ourselves on top of the 1290 * list. Such logic gives infrequent senders priority over frequent 1291 * senders. 1292 * 1293 * Note on byte count management. As long as event methods kevent(2), 1294 * select(2) are not protocol specific (yet), we need to maintain 1295 * meaningful values on the receive buffer. So, the receive buffer 1296 * would accumulate counters from all connected buffers potentially 1297 * having sb_ccc > sb_hiwat or sb_mbcnt > sb_mbmax. 1298 */ 1299 so2 = unp2->unp_socket; 1300 sb = (addr == NULL) ? &so->so_snd : &so2->so_rcv; 1301 SOCK_RECVBUF_LOCK(so2); 1302 if (uipc_dgram_sbspace(sb, cc + ctl, mbcnt)) { 1303 if (addr == NULL && STAILQ_EMPTY(&sb->uxdg_mb)) 1304 TAILQ_INSERT_HEAD(&so2->so_rcv.uxdg_conns, &so->so_snd, 1305 uxdg_clist); 1306 STAILQ_INSERT_TAIL(&sb->uxdg_mb, f, m_stailqpkt); 1307 sb->uxdg_cc += cc + ctl; 1308 sb->uxdg_ctl += ctl; 1309 sb->uxdg_mbcnt += mbcnt; 1310 so2->so_rcv.sb_acc += cc + ctl; 1311 so2->so_rcv.sb_ccc += cc + ctl; 1312 so2->so_rcv.sb_ctl += ctl; 1313 so2->so_rcv.sb_mbcnt += mbcnt; 1314 sorwakeup_locked(so2); 1315 f = NULL; 1316 } else { 1317 soroverflow_locked(so2); 1318 error = ENOBUFS; 1319 if (f->m_next->m_type == MT_CONTROL) { 1320 c = f->m_next; 1321 f->m_next = NULL; 1322 } 1323 } 1324 1325 if (addr != NULL) 1326 unp_disconnect(unp, unp2); 1327 else 1328 unp_pcb_unlock_pair(unp, unp2); 1329 1330 td->td_ru.ru_msgsnd++; 1331 1332 out3: 1333 SOCK_IO_SEND_UNLOCK(so); 1334 out2: 1335 if (c) 1336 unp_scan(c, unp_freerights); 1337 out: 1338 if (f) 1339 m_freem(f); 1340 if (c) 1341 m_freem(c); 1342 if (m) 1343 m_freem(m); 1344 1345 return (error); 1346 } 1347 1348 /* 1349 * PF_UNIX/SOCK_DGRAM receive with MSG_PEEK. 1350 * The mbuf has already been unlinked from the uxdg_mb of socket buffer 1351 * and needs to be linked onto uxdg_peeked of receive socket buffer. 1352 */ 1353 static int 1354 uipc_peek_dgram(struct socket *so, struct mbuf *m, struct sockaddr **psa, 1355 struct uio *uio, struct mbuf **controlp, int *flagsp) 1356 { 1357 ssize_t len = 0; 1358 int error; 1359 1360 so->so_rcv.uxdg_peeked = m; 1361 so->so_rcv.uxdg_cc += m->m_pkthdr.len; 1362 so->so_rcv.uxdg_ctl += m->m_pkthdr.ctllen; 1363 so->so_rcv.uxdg_mbcnt += m->m_pkthdr.memlen; 1364 SOCK_RECVBUF_UNLOCK(so); 1365 1366 KASSERT(m->m_type == MT_SONAME, ("m->m_type == %d", m->m_type)); 1367 if (psa != NULL) 1368 *psa = sodupsockaddr(mtod(m, struct sockaddr *), M_WAITOK); 1369 1370 m = m->m_next; 1371 KASSERT(m, ("%s: no data or control after soname", __func__)); 1372 1373 /* 1374 * With MSG_PEEK the control isn't executed, just copied. 1375 */ 1376 while (m != NULL && m->m_type == MT_CONTROL) { 1377 if (controlp != NULL) { 1378 *controlp = m_copym(m, 0, m->m_len, M_WAITOK); 1379 controlp = &(*controlp)->m_next; 1380 } 1381 m = m->m_next; 1382 } 1383 KASSERT(m == NULL || m->m_type == MT_DATA, 1384 ("%s: not MT_DATA mbuf %p", __func__, m)); 1385 while (m != NULL && uio->uio_resid > 0) { 1386 len = uio->uio_resid; 1387 if (len > m->m_len) 1388 len = m->m_len; 1389 error = uiomove(mtod(m, char *), (int)len, uio); 1390 if (error) { 1391 SOCK_IO_RECV_UNLOCK(so); 1392 return (error); 1393 } 1394 if (len == m->m_len) 1395 m = m->m_next; 1396 } 1397 SOCK_IO_RECV_UNLOCK(so); 1398 1399 if (flagsp != NULL) { 1400 if (m != NULL) { 1401 if (*flagsp & MSG_TRUNC) { 1402 /* Report real length of the packet */ 1403 uio->uio_resid -= m_length(m, NULL) - len; 1404 } 1405 *flagsp |= MSG_TRUNC; 1406 } else 1407 *flagsp &= ~MSG_TRUNC; 1408 } 1409 1410 return (0); 1411 } 1412 1413 /* 1414 * PF_UNIX/SOCK_DGRAM receive 1415 */ 1416 static int 1417 uipc_soreceive_dgram(struct socket *so, struct sockaddr **psa, struct uio *uio, 1418 struct mbuf **mp0, struct mbuf **controlp, int *flagsp) 1419 { 1420 struct sockbuf *sb = NULL; 1421 struct mbuf *m; 1422 int flags, error; 1423 ssize_t len = 0; 1424 bool nonblock; 1425 1426 MPASS(mp0 == NULL); 1427 1428 if (psa != NULL) 1429 *psa = NULL; 1430 if (controlp != NULL) 1431 *controlp = NULL; 1432 1433 flags = flagsp != NULL ? *flagsp : 0; 1434 nonblock = (so->so_state & SS_NBIO) || 1435 (flags & (MSG_DONTWAIT | MSG_NBIO)); 1436 1437 error = SOCK_IO_RECV_LOCK(so, SBLOCKWAIT(flags)); 1438 if (__predict_false(error)) 1439 return (error); 1440 1441 /* 1442 * Loop blocking while waiting for a datagram. Prioritize connected 1443 * peers over unconnected sends. Set sb to selected socket buffer 1444 * containing an mbuf on exit from the wait loop. A datagram that 1445 * had already been peeked at has top priority. 1446 */ 1447 SOCK_RECVBUF_LOCK(so); 1448 while ((m = so->so_rcv.uxdg_peeked) == NULL && 1449 (sb = TAILQ_FIRST(&so->so_rcv.uxdg_conns)) == NULL && 1450 (m = STAILQ_FIRST(&so->so_rcv.uxdg_mb)) == NULL) { 1451 if (so->so_error) { 1452 error = so->so_error; 1453 if (!(flags & MSG_PEEK)) 1454 so->so_error = 0; 1455 SOCK_RECVBUF_UNLOCK(so); 1456 SOCK_IO_RECV_UNLOCK(so); 1457 return (error); 1458 } 1459 if (so->so_rcv.sb_state & SBS_CANTRCVMORE || 1460 uio->uio_resid == 0) { 1461 SOCK_RECVBUF_UNLOCK(so); 1462 SOCK_IO_RECV_UNLOCK(so); 1463 return (0); 1464 } 1465 if (nonblock) { 1466 SOCK_RECVBUF_UNLOCK(so); 1467 SOCK_IO_RECV_UNLOCK(so); 1468 return (EWOULDBLOCK); 1469 } 1470 error = sbwait(so, SO_RCV); 1471 if (error) { 1472 SOCK_RECVBUF_UNLOCK(so); 1473 SOCK_IO_RECV_UNLOCK(so); 1474 return (error); 1475 } 1476 } 1477 1478 if (sb == NULL) 1479 sb = &so->so_rcv; 1480 else if (m == NULL) 1481 m = STAILQ_FIRST(&sb->uxdg_mb); 1482 else 1483 MPASS(m == so->so_rcv.uxdg_peeked); 1484 1485 MPASS(sb->uxdg_cc > 0); 1486 M_ASSERTPKTHDR(m); 1487 KASSERT(m->m_type == MT_SONAME, ("m->m_type == %d", m->m_type)); 1488 1489 if (uio->uio_td) 1490 uio->uio_td->td_ru.ru_msgrcv++; 1491 1492 if (__predict_true(m != so->so_rcv.uxdg_peeked)) { 1493 STAILQ_REMOVE_HEAD(&sb->uxdg_mb, m_stailqpkt); 1494 if (STAILQ_EMPTY(&sb->uxdg_mb) && sb != &so->so_rcv) 1495 TAILQ_REMOVE(&so->so_rcv.uxdg_conns, sb, uxdg_clist); 1496 } else 1497 so->so_rcv.uxdg_peeked = NULL; 1498 1499 sb->uxdg_cc -= m->m_pkthdr.len; 1500 sb->uxdg_ctl -= m->m_pkthdr.ctllen; 1501 sb->uxdg_mbcnt -= m->m_pkthdr.memlen; 1502 1503 if (__predict_false(flags & MSG_PEEK)) 1504 return (uipc_peek_dgram(so, m, psa, uio, controlp, flagsp)); 1505 1506 so->so_rcv.sb_acc -= m->m_pkthdr.len; 1507 so->so_rcv.sb_ccc -= m->m_pkthdr.len; 1508 so->so_rcv.sb_ctl -= m->m_pkthdr.ctllen; 1509 so->so_rcv.sb_mbcnt -= m->m_pkthdr.memlen; 1510 SOCK_RECVBUF_UNLOCK(so); 1511 1512 if (psa != NULL) 1513 *psa = sodupsockaddr(mtod(m, struct sockaddr *), M_WAITOK); 1514 m = m_free(m); 1515 KASSERT(m, ("%s: no data or control after soname", __func__)); 1516 1517 /* 1518 * Packet to copyout() is now in 'm' and it is disconnected from the 1519 * queue. 1520 * 1521 * Process one or more MT_CONTROL mbufs present before any data mbufs 1522 * in the first mbuf chain on the socket buffer. We call into the 1523 * unp_externalize() to perform externalization (or freeing if 1524 * controlp == NULL). In some cases there can be only MT_CONTROL mbufs 1525 * without MT_DATA mbufs. 1526 */ 1527 while (m != NULL && m->m_type == MT_CONTROL) { 1528 struct mbuf *cm; 1529 1530 /* XXXGL: unp_externalize() is also dom_externalize() KBI and 1531 * it frees whole chain, so we must disconnect the mbuf. 1532 */ 1533 cm = m; m = m->m_next; cm->m_next = NULL; 1534 error = unp_externalize(cm, controlp, flags); 1535 if (error != 0) { 1536 SOCK_IO_RECV_UNLOCK(so); 1537 unp_scan(m, unp_freerights); 1538 m_freem(m); 1539 return (error); 1540 } 1541 if (controlp != NULL) { 1542 while (*controlp != NULL) 1543 controlp = &(*controlp)->m_next; 1544 } 1545 } 1546 KASSERT(m == NULL || m->m_type == MT_DATA, 1547 ("%s: not MT_DATA mbuf %p", __func__, m)); 1548 while (m != NULL && uio->uio_resid > 0) { 1549 len = uio->uio_resid; 1550 if (len > m->m_len) 1551 len = m->m_len; 1552 error = uiomove(mtod(m, char *), (int)len, uio); 1553 if (error) { 1554 SOCK_IO_RECV_UNLOCK(so); 1555 m_freem(m); 1556 return (error); 1557 } 1558 if (len == m->m_len) 1559 m = m_free(m); 1560 else { 1561 m->m_data += len; 1562 m->m_len -= len; 1563 } 1564 } 1565 SOCK_IO_RECV_UNLOCK(so); 1566 1567 if (m != NULL) { 1568 if (flagsp != NULL) { 1569 if (flags & MSG_TRUNC) { 1570 /* Report real length of the packet */ 1571 uio->uio_resid -= m_length(m, NULL); 1572 } 1573 *flagsp |= MSG_TRUNC; 1574 } 1575 m_freem(m); 1576 } else if (flagsp != NULL) 1577 *flagsp &= ~MSG_TRUNC; 1578 1579 return (0); 1580 } 1581 1582 static bool 1583 uipc_ready_scan(struct socket *so, struct mbuf *m, int count, int *errorp) 1584 { 1585 struct mbuf *mb, *n; 1586 struct sockbuf *sb; 1587 1588 SOCK_LOCK(so); 1589 if (SOLISTENING(so)) { 1590 SOCK_UNLOCK(so); 1591 return (false); 1592 } 1593 mb = NULL; 1594 sb = &so->so_rcv; 1595 SOCKBUF_LOCK(sb); 1596 if (sb->sb_fnrdy != NULL) { 1597 for (mb = sb->sb_mb, n = mb->m_nextpkt; mb != NULL;) { 1598 if (mb == m) { 1599 *errorp = sbready(sb, m, count); 1600 break; 1601 } 1602 mb = mb->m_next; 1603 if (mb == NULL) { 1604 mb = n; 1605 if (mb != NULL) 1606 n = mb->m_nextpkt; 1607 } 1608 } 1609 } 1610 SOCKBUF_UNLOCK(sb); 1611 SOCK_UNLOCK(so); 1612 return (mb != NULL); 1613 } 1614 1615 static int 1616 uipc_ready(struct socket *so, struct mbuf *m, int count) 1617 { 1618 struct unpcb *unp, *unp2; 1619 struct socket *so2; 1620 int error, i; 1621 1622 unp = sotounpcb(so); 1623 1624 KASSERT(so->so_type == SOCK_STREAM, 1625 ("%s: unexpected socket type for %p", __func__, so)); 1626 1627 UNP_PCB_LOCK(unp); 1628 if ((unp2 = unp_pcb_lock_peer(unp)) != NULL) { 1629 UNP_PCB_UNLOCK(unp); 1630 so2 = unp2->unp_socket; 1631 SOCKBUF_LOCK(&so2->so_rcv); 1632 if ((error = sbready(&so2->so_rcv, m, count)) == 0) 1633 sorwakeup_locked(so2); 1634 else 1635 SOCKBUF_UNLOCK(&so2->so_rcv); 1636 UNP_PCB_UNLOCK(unp2); 1637 return (error); 1638 } 1639 UNP_PCB_UNLOCK(unp); 1640 1641 /* 1642 * The receiving socket has been disconnected, but may still be valid. 1643 * In this case, the now-ready mbufs are still present in its socket 1644 * buffer, so perform an exhaustive search before giving up and freeing 1645 * the mbufs. 1646 */ 1647 UNP_LINK_RLOCK(); 1648 LIST_FOREACH(unp, &unp_shead, unp_link) { 1649 if (uipc_ready_scan(unp->unp_socket, m, count, &error)) 1650 break; 1651 } 1652 UNP_LINK_RUNLOCK(); 1653 1654 if (unp == NULL) { 1655 for (i = 0; i < count; i++) 1656 m = m_free(m); 1657 error = ECONNRESET; 1658 } 1659 return (error); 1660 } 1661 1662 static int 1663 uipc_sense(struct socket *so, struct stat *sb) 1664 { 1665 struct unpcb *unp; 1666 1667 unp = sotounpcb(so); 1668 KASSERT(unp != NULL, ("uipc_sense: unp == NULL")); 1669 1670 sb->st_blksize = so->so_snd.sb_hiwat; 1671 sb->st_dev = NODEV; 1672 sb->st_ino = unp->unp_ino; 1673 return (0); 1674 } 1675 1676 static int 1677 uipc_shutdown(struct socket *so, enum shutdown_how how) 1678 { 1679 struct unpcb *unp = sotounpcb(so); 1680 int error; 1681 1682 SOCK_LOCK(so); 1683 if (SOLISTENING(so)) { 1684 if (how != SHUT_WR) { 1685 so->so_error = ECONNABORTED; 1686 solisten_wakeup(so); /* unlocks so */ 1687 } else 1688 SOCK_UNLOCK(so); 1689 return (ENOTCONN); 1690 } else if ((so->so_state & 1691 (SS_ISCONNECTED | SS_ISCONNECTING | SS_ISDISCONNECTING)) == 0) { 1692 /* 1693 * POSIX mandates us to just return ENOTCONN when shutdown(2) is 1694 * invoked on a datagram sockets, however historically we would 1695 * actually tear socket down. This is known to be leveraged by 1696 * some applications to unblock process waiting in recv(2) by 1697 * other process that it shares that socket with. Try to meet 1698 * both backward-compatibility and POSIX requirements by forcing 1699 * ENOTCONN but still flushing buffers and performing wakeup(9). 1700 * 1701 * XXXGL: it remains unknown what applications expect this 1702 * behavior and is this isolated to unix/dgram or inet/dgram or 1703 * both. See: D10351, D3039. 1704 */ 1705 error = ENOTCONN; 1706 if (so->so_type != SOCK_DGRAM) { 1707 SOCK_UNLOCK(so); 1708 return (error); 1709 } 1710 } else 1711 error = 0; 1712 SOCK_UNLOCK(so); 1713 1714 switch (how) { 1715 case SHUT_RD: 1716 socantrcvmore(so); 1717 unp_dispose(so); 1718 break; 1719 case SHUT_RDWR: 1720 socantrcvmore(so); 1721 unp_dispose(so); 1722 /* FALLTHROUGH */ 1723 case SHUT_WR: 1724 UNP_PCB_LOCK(unp); 1725 socantsendmore(so); 1726 unp_shutdown(unp); 1727 UNP_PCB_UNLOCK(unp); 1728 } 1729 wakeup(&so->so_timeo); 1730 1731 return (error); 1732 } 1733 1734 static int 1735 uipc_sockaddr(struct socket *so, struct sockaddr *ret) 1736 { 1737 struct unpcb *unp; 1738 const struct sockaddr *sa; 1739 1740 unp = sotounpcb(so); 1741 KASSERT(unp != NULL, ("uipc_sockaddr: unp == NULL")); 1742 1743 UNP_PCB_LOCK(unp); 1744 if (unp->unp_addr != NULL) 1745 sa = (struct sockaddr *) unp->unp_addr; 1746 else 1747 sa = &sun_noname; 1748 bcopy(sa, ret, sa->sa_len); 1749 UNP_PCB_UNLOCK(unp); 1750 return (0); 1751 } 1752 1753 static int 1754 uipc_ctloutput(struct socket *so, struct sockopt *sopt) 1755 { 1756 struct unpcb *unp; 1757 struct xucred xu; 1758 int error, optval; 1759 1760 if (sopt->sopt_level != SOL_LOCAL) 1761 return (EINVAL); 1762 1763 unp = sotounpcb(so); 1764 KASSERT(unp != NULL, ("uipc_ctloutput: unp == NULL")); 1765 error = 0; 1766 switch (sopt->sopt_dir) { 1767 case SOPT_GET: 1768 switch (sopt->sopt_name) { 1769 case LOCAL_PEERCRED: 1770 UNP_PCB_LOCK(unp); 1771 if (unp->unp_flags & UNP_HAVEPC) 1772 xu = unp->unp_peercred; 1773 else { 1774 if (so->so_type == SOCK_STREAM) 1775 error = ENOTCONN; 1776 else 1777 error = EINVAL; 1778 } 1779 UNP_PCB_UNLOCK(unp); 1780 if (error == 0) 1781 error = sooptcopyout(sopt, &xu, sizeof(xu)); 1782 break; 1783 1784 case LOCAL_CREDS: 1785 /* Unlocked read. */ 1786 optval = unp->unp_flags & UNP_WANTCRED_ONESHOT ? 1 : 0; 1787 error = sooptcopyout(sopt, &optval, sizeof(optval)); 1788 break; 1789 1790 case LOCAL_CREDS_PERSISTENT: 1791 /* Unlocked read. */ 1792 optval = unp->unp_flags & UNP_WANTCRED_ALWAYS ? 1 : 0; 1793 error = sooptcopyout(sopt, &optval, sizeof(optval)); 1794 break; 1795 1796 default: 1797 error = EOPNOTSUPP; 1798 break; 1799 } 1800 break; 1801 1802 case SOPT_SET: 1803 switch (sopt->sopt_name) { 1804 case LOCAL_CREDS: 1805 case LOCAL_CREDS_PERSISTENT: 1806 error = sooptcopyin(sopt, &optval, sizeof(optval), 1807 sizeof(optval)); 1808 if (error) 1809 break; 1810 1811 #define OPTSET(bit, exclusive) do { \ 1812 UNP_PCB_LOCK(unp); \ 1813 if (optval) { \ 1814 if ((unp->unp_flags & (exclusive)) != 0) { \ 1815 UNP_PCB_UNLOCK(unp); \ 1816 error = EINVAL; \ 1817 break; \ 1818 } \ 1819 unp->unp_flags |= (bit); \ 1820 } else \ 1821 unp->unp_flags &= ~(bit); \ 1822 UNP_PCB_UNLOCK(unp); \ 1823 } while (0) 1824 1825 switch (sopt->sopt_name) { 1826 case LOCAL_CREDS: 1827 OPTSET(UNP_WANTCRED_ONESHOT, UNP_WANTCRED_ALWAYS); 1828 break; 1829 1830 case LOCAL_CREDS_PERSISTENT: 1831 OPTSET(UNP_WANTCRED_ALWAYS, UNP_WANTCRED_ONESHOT); 1832 break; 1833 1834 default: 1835 break; 1836 } 1837 break; 1838 #undef OPTSET 1839 default: 1840 error = ENOPROTOOPT; 1841 break; 1842 } 1843 break; 1844 1845 default: 1846 error = EOPNOTSUPP; 1847 break; 1848 } 1849 return (error); 1850 } 1851 1852 static int 1853 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 1854 { 1855 1856 return (unp_connectat(AT_FDCWD, so, nam, td, false)); 1857 } 1858 1859 static int 1860 unp_connectat(int fd, struct socket *so, struct sockaddr *nam, 1861 struct thread *td, bool return_locked) 1862 { 1863 struct mtx *vplock; 1864 struct sockaddr_un *soun; 1865 struct vnode *vp; 1866 struct socket *so2; 1867 struct unpcb *unp, *unp2, *unp3; 1868 struct nameidata nd; 1869 char buf[SOCK_MAXADDRLEN]; 1870 struct sockaddr *sa; 1871 cap_rights_t rights; 1872 int error, len; 1873 bool connreq; 1874 1875 if (nam->sa_family != AF_UNIX) 1876 return (EAFNOSUPPORT); 1877 if (nam->sa_len > sizeof(struct sockaddr_un)) 1878 return (EINVAL); 1879 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); 1880 if (len <= 0) 1881 return (EINVAL); 1882 soun = (struct sockaddr_un *)nam; 1883 bcopy(soun->sun_path, buf, len); 1884 buf[len] = 0; 1885 1886 error = 0; 1887 unp = sotounpcb(so); 1888 UNP_PCB_LOCK(unp); 1889 for (;;) { 1890 /* 1891 * Wait for connection state to stabilize. If a connection 1892 * already exists, give up. For datagram sockets, which permit 1893 * multiple consecutive connect(2) calls, upper layers are 1894 * responsible for disconnecting in advance of a subsequent 1895 * connect(2), but this is not synchronized with PCB connection 1896 * state. 1897 * 1898 * Also make sure that no threads are currently attempting to 1899 * lock the peer socket, to ensure that unp_conn cannot 1900 * transition between two valid sockets while locks are dropped. 1901 */ 1902 if (SOLISTENING(so)) 1903 error = EOPNOTSUPP; 1904 else if (unp->unp_conn != NULL) 1905 error = EISCONN; 1906 else if ((unp->unp_flags & UNP_CONNECTING) != 0) { 1907 error = EALREADY; 1908 } 1909 if (error != 0) { 1910 UNP_PCB_UNLOCK(unp); 1911 return (error); 1912 } 1913 if (unp->unp_pairbusy > 0) { 1914 unp->unp_flags |= UNP_WAITING; 1915 mtx_sleep(unp, UNP_PCB_LOCKPTR(unp), 0, "unpeer", 0); 1916 continue; 1917 } 1918 break; 1919 } 1920 unp->unp_flags |= UNP_CONNECTING; 1921 UNP_PCB_UNLOCK(unp); 1922 1923 connreq = (so->so_proto->pr_flags & PR_CONNREQUIRED) != 0; 1924 if (connreq) 1925 sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 1926 else 1927 sa = NULL; 1928 NDINIT_ATRIGHTS(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF, 1929 UIO_SYSSPACE, buf, fd, cap_rights_init_one(&rights, CAP_CONNECTAT)); 1930 error = namei(&nd); 1931 if (error) 1932 vp = NULL; 1933 else 1934 vp = nd.ni_vp; 1935 ASSERT_VOP_LOCKED(vp, "unp_connect"); 1936 if (error) 1937 goto bad; 1938 NDFREE_PNBUF(&nd); 1939 1940 if (vp->v_type != VSOCK) { 1941 error = ENOTSOCK; 1942 goto bad; 1943 } 1944 #ifdef MAC 1945 error = mac_vnode_check_open(td->td_ucred, vp, VWRITE | VREAD); 1946 if (error) 1947 goto bad; 1948 #endif 1949 error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td); 1950 if (error) 1951 goto bad; 1952 1953 unp = sotounpcb(so); 1954 KASSERT(unp != NULL, ("unp_connect: unp == NULL")); 1955 1956 vplock = mtx_pool_find(mtxpool_sleep, vp); 1957 mtx_lock(vplock); 1958 VOP_UNP_CONNECT(vp, &unp2); 1959 if (unp2 == NULL) { 1960 error = ECONNREFUSED; 1961 goto bad2; 1962 } 1963 so2 = unp2->unp_socket; 1964 if (so->so_type != so2->so_type) { 1965 error = EPROTOTYPE; 1966 goto bad2; 1967 } 1968 if (connreq) { 1969 if (SOLISTENING(so2)) { 1970 CURVNET_SET(so2->so_vnet); 1971 so2 = sonewconn(so2, 0); 1972 CURVNET_RESTORE(); 1973 } else 1974 so2 = NULL; 1975 if (so2 == NULL) { 1976 error = ECONNREFUSED; 1977 goto bad2; 1978 } 1979 unp3 = sotounpcb(so2); 1980 unp_pcb_lock_pair(unp2, unp3); 1981 if (unp2->unp_addr != NULL) { 1982 bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len); 1983 unp3->unp_addr = (struct sockaddr_un *) sa; 1984 sa = NULL; 1985 } 1986 1987 unp_copy_peercred(td, unp3, unp, unp2); 1988 1989 UNP_PCB_UNLOCK(unp2); 1990 unp2 = unp3; 1991 1992 /* 1993 * It is safe to block on the PCB lock here since unp2 is 1994 * nascent and cannot be connected to any other sockets. 1995 */ 1996 UNP_PCB_LOCK(unp); 1997 #ifdef MAC 1998 mac_socketpeer_set_from_socket(so, so2); 1999 mac_socketpeer_set_from_socket(so2, so); 2000 #endif 2001 } else { 2002 unp_pcb_lock_pair(unp, unp2); 2003 } 2004 KASSERT(unp2 != NULL && so2 != NULL && unp2->unp_socket == so2 && 2005 sotounpcb(so2) == unp2, 2006 ("%s: unp2 %p so2 %p", __func__, unp2, so2)); 2007 unp_connect2(so, so2); 2008 KASSERT((unp->unp_flags & UNP_CONNECTING) != 0, 2009 ("%s: unp %p has UNP_CONNECTING clear", __func__, unp)); 2010 unp->unp_flags &= ~UNP_CONNECTING; 2011 if (!return_locked) 2012 unp_pcb_unlock_pair(unp, unp2); 2013 bad2: 2014 mtx_unlock(vplock); 2015 bad: 2016 if (vp != NULL) { 2017 /* 2018 * If we are returning locked (called via uipc_sosend_dgram()), 2019 * we need to be sure that vput() won't sleep. This is 2020 * guaranteed by VOP_UNP_CONNECT() call above and unp2 lock. 2021 * SOCK_STREAM/SEQPACKET can't request return_locked (yet). 2022 */ 2023 MPASS(!(return_locked && connreq)); 2024 vput(vp); 2025 } 2026 free(sa, M_SONAME); 2027 if (__predict_false(error)) { 2028 UNP_PCB_LOCK(unp); 2029 KASSERT((unp->unp_flags & UNP_CONNECTING) != 0, 2030 ("%s: unp %p has UNP_CONNECTING clear", __func__, unp)); 2031 unp->unp_flags &= ~UNP_CONNECTING; 2032 UNP_PCB_UNLOCK(unp); 2033 } 2034 return (error); 2035 } 2036 2037 /* 2038 * Set socket peer credentials at connection time. 2039 * 2040 * The client's PCB credentials are copied from its process structure. The 2041 * server's PCB credentials are copied from the socket on which it called 2042 * listen(2). uipc_listen cached that process's credentials at the time. 2043 */ 2044 void 2045 unp_copy_peercred(struct thread *td, struct unpcb *client_unp, 2046 struct unpcb *server_unp, struct unpcb *listen_unp) 2047 { 2048 cru2xt(td, &client_unp->unp_peercred); 2049 client_unp->unp_flags |= UNP_HAVEPC; 2050 2051 memcpy(&server_unp->unp_peercred, &listen_unp->unp_peercred, 2052 sizeof(server_unp->unp_peercred)); 2053 server_unp->unp_flags |= UNP_HAVEPC; 2054 client_unp->unp_flags |= (listen_unp->unp_flags & UNP_WANTCRED_MASK); 2055 } 2056 2057 static void 2058 unp_connect2(struct socket *so, struct socket *so2) 2059 { 2060 struct unpcb *unp; 2061 struct unpcb *unp2; 2062 2063 MPASS(so2->so_type == so->so_type); 2064 unp = sotounpcb(so); 2065 KASSERT(unp != NULL, ("unp_connect2: unp == NULL")); 2066 unp2 = sotounpcb(so2); 2067 KASSERT(unp2 != NULL, ("unp_connect2: unp2 == NULL")); 2068 2069 UNP_PCB_LOCK_ASSERT(unp); 2070 UNP_PCB_LOCK_ASSERT(unp2); 2071 KASSERT(unp->unp_conn == NULL, 2072 ("%s: socket %p is already connected", __func__, unp)); 2073 2074 unp->unp_conn = unp2; 2075 unp_pcb_hold(unp2); 2076 unp_pcb_hold(unp); 2077 switch (so->so_type) { 2078 case SOCK_DGRAM: 2079 UNP_REF_LIST_LOCK(); 2080 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); 2081 UNP_REF_LIST_UNLOCK(); 2082 soisconnected(so); 2083 break; 2084 2085 case SOCK_STREAM: 2086 case SOCK_SEQPACKET: 2087 KASSERT(unp2->unp_conn == NULL, 2088 ("%s: socket %p is already connected", __func__, unp2)); 2089 unp2->unp_conn = unp; 2090 soisconnected(so); 2091 soisconnected(so2); 2092 break; 2093 2094 default: 2095 panic("unp_connect2"); 2096 } 2097 } 2098 2099 static void 2100 unp_disconnect(struct unpcb *unp, struct unpcb *unp2) 2101 { 2102 struct socket *so, *so2; 2103 struct mbuf *m = NULL; 2104 #ifdef INVARIANTS 2105 struct unpcb *unptmp; 2106 #endif 2107 2108 UNP_PCB_LOCK_ASSERT(unp); 2109 UNP_PCB_LOCK_ASSERT(unp2); 2110 KASSERT(unp->unp_conn == unp2, 2111 ("%s: unpcb %p is not connected to %p", __func__, unp, unp2)); 2112 2113 unp->unp_conn = NULL; 2114 so = unp->unp_socket; 2115 so2 = unp2->unp_socket; 2116 switch (unp->unp_socket->so_type) { 2117 case SOCK_DGRAM: 2118 /* 2119 * Remove our send socket buffer from the peer's receive buffer. 2120 * Move the data to the receive buffer only if it is empty. 2121 * This is a protection against a scenario where a peer 2122 * connects, floods and disconnects, effectively blocking 2123 * sendto() from unconnected sockets. 2124 */ 2125 SOCK_RECVBUF_LOCK(so2); 2126 if (!STAILQ_EMPTY(&so->so_snd.uxdg_mb)) { 2127 TAILQ_REMOVE(&so2->so_rcv.uxdg_conns, &so->so_snd, 2128 uxdg_clist); 2129 if (__predict_true((so2->so_rcv.sb_state & 2130 SBS_CANTRCVMORE) == 0) && 2131 STAILQ_EMPTY(&so2->so_rcv.uxdg_mb)) { 2132 STAILQ_CONCAT(&so2->so_rcv.uxdg_mb, 2133 &so->so_snd.uxdg_mb); 2134 so2->so_rcv.uxdg_cc += so->so_snd.uxdg_cc; 2135 so2->so_rcv.uxdg_ctl += so->so_snd.uxdg_ctl; 2136 so2->so_rcv.uxdg_mbcnt += so->so_snd.uxdg_mbcnt; 2137 } else { 2138 m = STAILQ_FIRST(&so->so_snd.uxdg_mb); 2139 STAILQ_INIT(&so->so_snd.uxdg_mb); 2140 so2->so_rcv.sb_acc -= so->so_snd.uxdg_cc; 2141 so2->so_rcv.sb_ccc -= so->so_snd.uxdg_cc; 2142 so2->so_rcv.sb_ctl -= so->so_snd.uxdg_ctl; 2143 so2->so_rcv.sb_mbcnt -= so->so_snd.uxdg_mbcnt; 2144 } 2145 /* Note: so may reconnect. */ 2146 so->so_snd.uxdg_cc = 0; 2147 so->so_snd.uxdg_ctl = 0; 2148 so->so_snd.uxdg_mbcnt = 0; 2149 } 2150 SOCK_RECVBUF_UNLOCK(so2); 2151 UNP_REF_LIST_LOCK(); 2152 #ifdef INVARIANTS 2153 LIST_FOREACH(unptmp, &unp2->unp_refs, unp_reflink) { 2154 if (unptmp == unp) 2155 break; 2156 } 2157 KASSERT(unptmp != NULL, 2158 ("%s: %p not found in reflist of %p", __func__, unp, unp2)); 2159 #endif 2160 LIST_REMOVE(unp, unp_reflink); 2161 UNP_REF_LIST_UNLOCK(); 2162 if (so) { 2163 SOCK_LOCK(so); 2164 so->so_state &= ~SS_ISCONNECTED; 2165 SOCK_UNLOCK(so); 2166 } 2167 break; 2168 2169 case SOCK_STREAM: 2170 case SOCK_SEQPACKET: 2171 if (so) 2172 soisdisconnected(so); 2173 MPASS(unp2->unp_conn == unp); 2174 unp2->unp_conn = NULL; 2175 if (so2) 2176 soisdisconnected(so2); 2177 break; 2178 } 2179 2180 if (unp == unp2) { 2181 unp_pcb_rele_notlast(unp); 2182 if (!unp_pcb_rele(unp)) 2183 UNP_PCB_UNLOCK(unp); 2184 } else { 2185 if (!unp_pcb_rele(unp)) 2186 UNP_PCB_UNLOCK(unp); 2187 if (!unp_pcb_rele(unp2)) 2188 UNP_PCB_UNLOCK(unp2); 2189 } 2190 2191 if (m != NULL) { 2192 unp_scan(m, unp_freerights); 2193 m_freem(m); 2194 } 2195 } 2196 2197 /* 2198 * unp_pcblist() walks the global list of struct unpcb's to generate a 2199 * pointer list, bumping the refcount on each unpcb. It then copies them out 2200 * sequentially, validating the generation number on each to see if it has 2201 * been detached. All of this is necessary because copyout() may sleep on 2202 * disk I/O. 2203 */ 2204 static int 2205 unp_pcblist(SYSCTL_HANDLER_ARGS) 2206 { 2207 struct unpcb *unp, **unp_list; 2208 unp_gen_t gencnt; 2209 struct xunpgen *xug; 2210 struct unp_head *head; 2211 struct xunpcb *xu; 2212 u_int i; 2213 int error, n; 2214 2215 switch ((intptr_t)arg1) { 2216 case SOCK_STREAM: 2217 head = &unp_shead; 2218 break; 2219 2220 case SOCK_DGRAM: 2221 head = &unp_dhead; 2222 break; 2223 2224 case SOCK_SEQPACKET: 2225 head = &unp_sphead; 2226 break; 2227 2228 default: 2229 panic("unp_pcblist: arg1 %d", (int)(intptr_t)arg1); 2230 } 2231 2232 /* 2233 * The process of preparing the PCB list is too time-consuming and 2234 * resource-intensive to repeat twice on every request. 2235 */ 2236 if (req->oldptr == NULL) { 2237 n = unp_count; 2238 req->oldidx = 2 * (sizeof *xug) 2239 + (n + n/8) * sizeof(struct xunpcb); 2240 return (0); 2241 } 2242 2243 if (req->newptr != NULL) 2244 return (EPERM); 2245 2246 /* 2247 * OK, now we're committed to doing something. 2248 */ 2249 xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK | M_ZERO); 2250 UNP_LINK_RLOCK(); 2251 gencnt = unp_gencnt; 2252 n = unp_count; 2253 UNP_LINK_RUNLOCK(); 2254 2255 xug->xug_len = sizeof *xug; 2256 xug->xug_count = n; 2257 xug->xug_gen = gencnt; 2258 xug->xug_sogen = so_gencnt; 2259 error = SYSCTL_OUT(req, xug, sizeof *xug); 2260 if (error) { 2261 free(xug, M_TEMP); 2262 return (error); 2263 } 2264 2265 unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK); 2266 2267 UNP_LINK_RLOCK(); 2268 for (unp = LIST_FIRST(head), i = 0; unp && i < n; 2269 unp = LIST_NEXT(unp, unp_link)) { 2270 UNP_PCB_LOCK(unp); 2271 if (unp->unp_gencnt <= gencnt) { 2272 if (cr_cansee(req->td->td_ucred, 2273 unp->unp_socket->so_cred)) { 2274 UNP_PCB_UNLOCK(unp); 2275 continue; 2276 } 2277 unp_list[i++] = unp; 2278 unp_pcb_hold(unp); 2279 } 2280 UNP_PCB_UNLOCK(unp); 2281 } 2282 UNP_LINK_RUNLOCK(); 2283 n = i; /* In case we lost some during malloc. */ 2284 2285 error = 0; 2286 xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK | M_ZERO); 2287 for (i = 0; i < n; i++) { 2288 unp = unp_list[i]; 2289 UNP_PCB_LOCK(unp); 2290 if (unp_pcb_rele(unp)) 2291 continue; 2292 2293 if (unp->unp_gencnt <= gencnt) { 2294 xu->xu_len = sizeof *xu; 2295 xu->xu_unpp = (uintptr_t)unp; 2296 /* 2297 * XXX - need more locking here to protect against 2298 * connect/disconnect races for SMP. 2299 */ 2300 if (unp->unp_addr != NULL) 2301 bcopy(unp->unp_addr, &xu->xu_addr, 2302 unp->unp_addr->sun_len); 2303 else 2304 bzero(&xu->xu_addr, sizeof(xu->xu_addr)); 2305 if (unp->unp_conn != NULL && 2306 unp->unp_conn->unp_addr != NULL) 2307 bcopy(unp->unp_conn->unp_addr, 2308 &xu->xu_caddr, 2309 unp->unp_conn->unp_addr->sun_len); 2310 else 2311 bzero(&xu->xu_caddr, sizeof(xu->xu_caddr)); 2312 xu->unp_vnode = (uintptr_t)unp->unp_vnode; 2313 xu->unp_conn = (uintptr_t)unp->unp_conn; 2314 xu->xu_firstref = (uintptr_t)LIST_FIRST(&unp->unp_refs); 2315 xu->xu_nextref = (uintptr_t)LIST_NEXT(unp, unp_reflink); 2316 xu->unp_gencnt = unp->unp_gencnt; 2317 sotoxsocket(unp->unp_socket, &xu->xu_socket); 2318 UNP_PCB_UNLOCK(unp); 2319 error = SYSCTL_OUT(req, xu, sizeof *xu); 2320 } else { 2321 UNP_PCB_UNLOCK(unp); 2322 } 2323 } 2324 free(xu, M_TEMP); 2325 if (!error) { 2326 /* 2327 * Give the user an updated idea of our state. If the 2328 * generation differs from what we told her before, she knows 2329 * that something happened while we were processing this 2330 * request, and it might be necessary to retry. 2331 */ 2332 xug->xug_gen = unp_gencnt; 2333 xug->xug_sogen = so_gencnt; 2334 xug->xug_count = unp_count; 2335 error = SYSCTL_OUT(req, xug, sizeof *xug); 2336 } 2337 free(unp_list, M_TEMP); 2338 free(xug, M_TEMP); 2339 return (error); 2340 } 2341 2342 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, 2343 CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, 2344 (void *)(intptr_t)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb", 2345 "List of active local datagram sockets"); 2346 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, 2347 CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, 2348 (void *)(intptr_t)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb", 2349 "List of active local stream sockets"); 2350 SYSCTL_PROC(_net_local_seqpacket, OID_AUTO, pcblist, 2351 CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, 2352 (void *)(intptr_t)SOCK_SEQPACKET, 0, unp_pcblist, "S,xunpcb", 2353 "List of active local seqpacket sockets"); 2354 2355 static void 2356 unp_shutdown(struct unpcb *unp) 2357 { 2358 struct unpcb *unp2; 2359 struct socket *so; 2360 2361 UNP_PCB_LOCK_ASSERT(unp); 2362 2363 unp2 = unp->unp_conn; 2364 if ((unp->unp_socket->so_type == SOCK_STREAM || 2365 (unp->unp_socket->so_type == SOCK_SEQPACKET)) && unp2 != NULL) { 2366 so = unp2->unp_socket; 2367 if (so != NULL) 2368 socantrcvmore(so); 2369 } 2370 } 2371 2372 static void 2373 unp_drop(struct unpcb *unp) 2374 { 2375 struct socket *so; 2376 struct unpcb *unp2; 2377 2378 /* 2379 * Regardless of whether the socket's peer dropped the connection 2380 * with this socket by aborting or disconnecting, POSIX requires 2381 * that ECONNRESET is returned. 2382 */ 2383 2384 UNP_PCB_LOCK(unp); 2385 so = unp->unp_socket; 2386 if (so) 2387 so->so_error = ECONNRESET; 2388 if ((unp2 = unp_pcb_lock_peer(unp)) != NULL) { 2389 /* Last reference dropped in unp_disconnect(). */ 2390 unp_pcb_rele_notlast(unp); 2391 unp_disconnect(unp, unp2); 2392 } else if (!unp_pcb_rele(unp)) { 2393 UNP_PCB_UNLOCK(unp); 2394 } 2395 } 2396 2397 static void 2398 unp_freerights(struct filedescent **fdep, int fdcount) 2399 { 2400 struct file *fp; 2401 int i; 2402 2403 KASSERT(fdcount > 0, ("%s: fdcount %d", __func__, fdcount)); 2404 2405 for (i = 0; i < fdcount; i++) { 2406 fp = fdep[i]->fde_file; 2407 filecaps_free(&fdep[i]->fde_caps); 2408 unp_discard(fp); 2409 } 2410 free(fdep[0], M_FILECAPS); 2411 } 2412 2413 static int 2414 unp_externalize(struct mbuf *control, struct mbuf **controlp, int flags) 2415 { 2416 struct thread *td = curthread; /* XXX */ 2417 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 2418 int i; 2419 int *fdp; 2420 struct filedesc *fdesc = td->td_proc->p_fd; 2421 struct filedescent **fdep; 2422 void *data; 2423 socklen_t clen = control->m_len, datalen; 2424 int error, newfds; 2425 u_int newlen; 2426 2427 UNP_LINK_UNLOCK_ASSERT(); 2428 2429 error = 0; 2430 if (controlp != NULL) /* controlp == NULL => free control messages */ 2431 *controlp = NULL; 2432 while (cm != NULL) { 2433 MPASS(clen >= sizeof(*cm) && clen >= cm->cmsg_len); 2434 2435 data = CMSG_DATA(cm); 2436 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 2437 if (cm->cmsg_level == SOL_SOCKET 2438 && cm->cmsg_type == SCM_RIGHTS) { 2439 newfds = datalen / sizeof(*fdep); 2440 if (newfds == 0) 2441 goto next; 2442 fdep = data; 2443 2444 /* If we're not outputting the descriptors free them. */ 2445 if (error || controlp == NULL) { 2446 unp_freerights(fdep, newfds); 2447 goto next; 2448 } 2449 FILEDESC_XLOCK(fdesc); 2450 2451 /* 2452 * Now change each pointer to an fd in the global 2453 * table to an integer that is the index to the local 2454 * fd table entry that we set up to point to the 2455 * global one we are transferring. 2456 */ 2457 newlen = newfds * sizeof(int); 2458 *controlp = sbcreatecontrol(NULL, newlen, 2459 SCM_RIGHTS, SOL_SOCKET, M_WAITOK); 2460 2461 fdp = (int *) 2462 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 2463 if ((error = fdallocn(td, 0, fdp, newfds))) { 2464 FILEDESC_XUNLOCK(fdesc); 2465 unp_freerights(fdep, newfds); 2466 m_freem(*controlp); 2467 *controlp = NULL; 2468 goto next; 2469 } 2470 for (i = 0; i < newfds; i++, fdp++) { 2471 _finstall(fdesc, fdep[i]->fde_file, *fdp, 2472 (flags & MSG_CMSG_CLOEXEC) != 0 ? O_CLOEXEC : 0, 2473 &fdep[i]->fde_caps); 2474 unp_externalize_fp(fdep[i]->fde_file); 2475 } 2476 2477 /* 2478 * The new type indicates that the mbuf data refers to 2479 * kernel resources that may need to be released before 2480 * the mbuf is freed. 2481 */ 2482 m_chtype(*controlp, MT_EXTCONTROL); 2483 FILEDESC_XUNLOCK(fdesc); 2484 free(fdep[0], M_FILECAPS); 2485 } else { 2486 /* We can just copy anything else across. */ 2487 if (error || controlp == NULL) 2488 goto next; 2489 *controlp = sbcreatecontrol(NULL, datalen, 2490 cm->cmsg_type, cm->cmsg_level, M_WAITOK); 2491 bcopy(data, 2492 CMSG_DATA(mtod(*controlp, struct cmsghdr *)), 2493 datalen); 2494 } 2495 controlp = &(*controlp)->m_next; 2496 2497 next: 2498 if (CMSG_SPACE(datalen) < clen) { 2499 clen -= CMSG_SPACE(datalen); 2500 cm = (struct cmsghdr *) 2501 ((caddr_t)cm + CMSG_SPACE(datalen)); 2502 } else { 2503 clen = 0; 2504 cm = NULL; 2505 } 2506 } 2507 2508 m_freem(control); 2509 return (error); 2510 } 2511 2512 static void 2513 unp_zone_change(void *tag) 2514 { 2515 2516 uma_zone_set_max(unp_zone, maxsockets); 2517 } 2518 2519 #ifdef INVARIANTS 2520 static void 2521 unp_zdtor(void *mem, int size __unused, void *arg __unused) 2522 { 2523 struct unpcb *unp; 2524 2525 unp = mem; 2526 2527 KASSERT(LIST_EMPTY(&unp->unp_refs), 2528 ("%s: unpcb %p has lingering refs", __func__, unp)); 2529 KASSERT(unp->unp_socket == NULL, 2530 ("%s: unpcb %p has socket backpointer", __func__, unp)); 2531 KASSERT(unp->unp_vnode == NULL, 2532 ("%s: unpcb %p has vnode references", __func__, unp)); 2533 KASSERT(unp->unp_conn == NULL, 2534 ("%s: unpcb %p is still connected", __func__, unp)); 2535 KASSERT(unp->unp_addr == NULL, 2536 ("%s: unpcb %p has leaked addr", __func__, unp)); 2537 } 2538 #endif 2539 2540 static void 2541 unp_init(void *arg __unused) 2542 { 2543 uma_dtor dtor; 2544 2545 #ifdef INVARIANTS 2546 dtor = unp_zdtor; 2547 #else 2548 dtor = NULL; 2549 #endif 2550 unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, dtor, 2551 NULL, NULL, UMA_ALIGN_CACHE, 0); 2552 uma_zone_set_max(unp_zone, maxsockets); 2553 uma_zone_set_warning(unp_zone, "kern.ipc.maxsockets limit reached"); 2554 EVENTHANDLER_REGISTER(maxsockets_change, unp_zone_change, 2555 NULL, EVENTHANDLER_PRI_ANY); 2556 LIST_INIT(&unp_dhead); 2557 LIST_INIT(&unp_shead); 2558 LIST_INIT(&unp_sphead); 2559 SLIST_INIT(&unp_defers); 2560 TIMEOUT_TASK_INIT(taskqueue_thread, &unp_gc_task, 0, unp_gc, NULL); 2561 TASK_INIT(&unp_defer_task, 0, unp_process_defers, NULL); 2562 UNP_LINK_LOCK_INIT(); 2563 UNP_DEFERRED_LOCK_INIT(); 2564 } 2565 SYSINIT(unp_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_SECOND, unp_init, NULL); 2566 2567 static void 2568 unp_internalize_cleanup_rights(struct mbuf *control) 2569 { 2570 struct cmsghdr *cp; 2571 struct mbuf *m; 2572 void *data; 2573 socklen_t datalen; 2574 2575 for (m = control; m != NULL; m = m->m_next) { 2576 cp = mtod(m, struct cmsghdr *); 2577 if (cp->cmsg_level != SOL_SOCKET || 2578 cp->cmsg_type != SCM_RIGHTS) 2579 continue; 2580 data = CMSG_DATA(cp); 2581 datalen = (caddr_t)cp + cp->cmsg_len - (caddr_t)data; 2582 unp_freerights(data, datalen / sizeof(struct filedesc *)); 2583 } 2584 } 2585 2586 static int 2587 unp_internalize(struct mbuf **controlp, struct thread *td, 2588 struct mbuf **clast, u_int *space, u_int *mbcnt) 2589 { 2590 struct mbuf *control, **initial_controlp; 2591 struct proc *p; 2592 struct filedesc *fdesc; 2593 struct bintime *bt; 2594 struct cmsghdr *cm; 2595 struct cmsgcred *cmcred; 2596 struct filedescent *fde, **fdep, *fdev; 2597 struct file *fp; 2598 struct timeval *tv; 2599 struct timespec *ts; 2600 void *data; 2601 socklen_t clen, datalen; 2602 int i, j, error, *fdp, oldfds; 2603 u_int newlen; 2604 2605 MPASS((*controlp)->m_next == NULL); /* COMPAT_OLDSOCK may violate */ 2606 UNP_LINK_UNLOCK_ASSERT(); 2607 2608 p = td->td_proc; 2609 fdesc = p->p_fd; 2610 error = 0; 2611 control = *controlp; 2612 *controlp = NULL; 2613 initial_controlp = controlp; 2614 for (clen = control->m_len, cm = mtod(control, struct cmsghdr *), 2615 data = CMSG_DATA(cm); 2616 2617 clen >= sizeof(*cm) && cm->cmsg_level == SOL_SOCKET && 2618 clen >= cm->cmsg_len && cm->cmsg_len >= sizeof(*cm) && 2619 (char *)cm + cm->cmsg_len >= (char *)data; 2620 2621 clen -= min(CMSG_SPACE(datalen), clen), 2622 cm = (struct cmsghdr *) ((char *)cm + CMSG_SPACE(datalen)), 2623 data = CMSG_DATA(cm)) { 2624 datalen = (char *)cm + cm->cmsg_len - (char *)data; 2625 switch (cm->cmsg_type) { 2626 case SCM_CREDS: 2627 *controlp = sbcreatecontrol(NULL, sizeof(*cmcred), 2628 SCM_CREDS, SOL_SOCKET, M_WAITOK); 2629 cmcred = (struct cmsgcred *) 2630 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 2631 cmcred->cmcred_pid = p->p_pid; 2632 cmcred->cmcred_uid = td->td_ucred->cr_ruid; 2633 cmcred->cmcred_gid = td->td_ucred->cr_rgid; 2634 cmcred->cmcred_euid = td->td_ucred->cr_uid; 2635 cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups, 2636 CMGROUP_MAX); 2637 for (i = 0; i < cmcred->cmcred_ngroups; i++) 2638 cmcred->cmcred_groups[i] = 2639 td->td_ucred->cr_groups[i]; 2640 break; 2641 2642 case SCM_RIGHTS: 2643 oldfds = datalen / sizeof (int); 2644 if (oldfds == 0) 2645 continue; 2646 /* On some machines sizeof pointer is bigger than 2647 * sizeof int, so we need to check if data fits into 2648 * single mbuf. We could allocate several mbufs, and 2649 * unp_externalize() should even properly handle that. 2650 * But it is not worth to complicate the code for an 2651 * insane scenario of passing over 200 file descriptors 2652 * at once. 2653 */ 2654 newlen = oldfds * sizeof(fdep[0]); 2655 if (CMSG_SPACE(newlen) > MCLBYTES) { 2656 error = EMSGSIZE; 2657 goto out; 2658 } 2659 /* 2660 * Check that all the FDs passed in refer to legal 2661 * files. If not, reject the entire operation. 2662 */ 2663 fdp = data; 2664 FILEDESC_SLOCK(fdesc); 2665 for (i = 0; i < oldfds; i++, fdp++) { 2666 fp = fget_noref(fdesc, *fdp); 2667 if (fp == NULL) { 2668 FILEDESC_SUNLOCK(fdesc); 2669 error = EBADF; 2670 goto out; 2671 } 2672 if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) { 2673 FILEDESC_SUNLOCK(fdesc); 2674 error = EOPNOTSUPP; 2675 goto out; 2676 } 2677 } 2678 2679 /* 2680 * Now replace the integer FDs with pointers to the 2681 * file structure and capability rights. 2682 */ 2683 *controlp = sbcreatecontrol(NULL, newlen, 2684 SCM_RIGHTS, SOL_SOCKET, M_WAITOK); 2685 fdp = data; 2686 for (i = 0; i < oldfds; i++, fdp++) { 2687 if (!fhold(fdesc->fd_ofiles[*fdp].fde_file)) { 2688 fdp = data; 2689 for (j = 0; j < i; j++, fdp++) { 2690 fdrop(fdesc->fd_ofiles[*fdp]. 2691 fde_file, td); 2692 } 2693 FILEDESC_SUNLOCK(fdesc); 2694 error = EBADF; 2695 goto out; 2696 } 2697 } 2698 fdp = data; 2699 fdep = (struct filedescent **) 2700 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 2701 fdev = malloc(sizeof(*fdev) * oldfds, M_FILECAPS, 2702 M_WAITOK); 2703 for (i = 0; i < oldfds; i++, fdev++, fdp++) { 2704 fde = &fdesc->fd_ofiles[*fdp]; 2705 fdep[i] = fdev; 2706 fdep[i]->fde_file = fde->fde_file; 2707 filecaps_copy(&fde->fde_caps, 2708 &fdep[i]->fde_caps, true); 2709 unp_internalize_fp(fdep[i]->fde_file); 2710 } 2711 FILEDESC_SUNLOCK(fdesc); 2712 break; 2713 2714 case SCM_TIMESTAMP: 2715 *controlp = sbcreatecontrol(NULL, sizeof(*tv), 2716 SCM_TIMESTAMP, SOL_SOCKET, M_WAITOK); 2717 tv = (struct timeval *) 2718 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 2719 microtime(tv); 2720 break; 2721 2722 case SCM_BINTIME: 2723 *controlp = sbcreatecontrol(NULL, sizeof(*bt), 2724 SCM_BINTIME, SOL_SOCKET, M_WAITOK); 2725 bt = (struct bintime *) 2726 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 2727 bintime(bt); 2728 break; 2729 2730 case SCM_REALTIME: 2731 *controlp = sbcreatecontrol(NULL, sizeof(*ts), 2732 SCM_REALTIME, SOL_SOCKET, M_WAITOK); 2733 ts = (struct timespec *) 2734 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 2735 nanotime(ts); 2736 break; 2737 2738 case SCM_MONOTONIC: 2739 *controlp = sbcreatecontrol(NULL, sizeof(*ts), 2740 SCM_MONOTONIC, SOL_SOCKET, M_WAITOK); 2741 ts = (struct timespec *) 2742 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 2743 nanouptime(ts); 2744 break; 2745 2746 default: 2747 error = EINVAL; 2748 goto out; 2749 } 2750 2751 if (space != NULL) { 2752 *space += (*controlp)->m_len; 2753 *mbcnt += MSIZE; 2754 if ((*controlp)->m_flags & M_EXT) 2755 *mbcnt += (*controlp)->m_ext.ext_size; 2756 *clast = *controlp; 2757 } 2758 controlp = &(*controlp)->m_next; 2759 } 2760 if (clen > 0) 2761 error = EINVAL; 2762 2763 out: 2764 if (error != 0 && initial_controlp != NULL) 2765 unp_internalize_cleanup_rights(*initial_controlp); 2766 m_freem(control); 2767 return (error); 2768 } 2769 2770 static struct mbuf * 2771 unp_addsockcred(struct thread *td, struct mbuf *control, int mode, 2772 struct mbuf **clast, u_int *space, u_int *mbcnt) 2773 { 2774 struct mbuf *m, *n, *n_prev; 2775 const struct cmsghdr *cm; 2776 int ngroups, i, cmsgtype; 2777 size_t ctrlsz; 2778 2779 ngroups = MIN(td->td_ucred->cr_ngroups, CMGROUP_MAX); 2780 if (mode & UNP_WANTCRED_ALWAYS) { 2781 ctrlsz = SOCKCRED2SIZE(ngroups); 2782 cmsgtype = SCM_CREDS2; 2783 } else { 2784 ctrlsz = SOCKCREDSIZE(ngroups); 2785 cmsgtype = SCM_CREDS; 2786 } 2787 2788 m = sbcreatecontrol(NULL, ctrlsz, cmsgtype, SOL_SOCKET, M_NOWAIT); 2789 if (m == NULL) 2790 return (control); 2791 MPASS((m->m_flags & M_EXT) == 0 && m->m_next == NULL); 2792 2793 if (mode & UNP_WANTCRED_ALWAYS) { 2794 struct sockcred2 *sc; 2795 2796 sc = (void *)CMSG_DATA(mtod(m, struct cmsghdr *)); 2797 sc->sc_version = 0; 2798 sc->sc_pid = td->td_proc->p_pid; 2799 sc->sc_uid = td->td_ucred->cr_ruid; 2800 sc->sc_euid = td->td_ucred->cr_uid; 2801 sc->sc_gid = td->td_ucred->cr_rgid; 2802 sc->sc_egid = td->td_ucred->cr_gid; 2803 sc->sc_ngroups = ngroups; 2804 for (i = 0; i < sc->sc_ngroups; i++) 2805 sc->sc_groups[i] = td->td_ucred->cr_groups[i]; 2806 } else { 2807 struct sockcred *sc; 2808 2809 sc = (void *)CMSG_DATA(mtod(m, struct cmsghdr *)); 2810 sc->sc_uid = td->td_ucred->cr_ruid; 2811 sc->sc_euid = td->td_ucred->cr_uid; 2812 sc->sc_gid = td->td_ucred->cr_rgid; 2813 sc->sc_egid = td->td_ucred->cr_gid; 2814 sc->sc_ngroups = ngroups; 2815 for (i = 0; i < sc->sc_ngroups; i++) 2816 sc->sc_groups[i] = td->td_ucred->cr_groups[i]; 2817 } 2818 2819 /* 2820 * Unlink SCM_CREDS control messages (struct cmsgcred), since just 2821 * created SCM_CREDS control message (struct sockcred) has another 2822 * format. 2823 */ 2824 if (control != NULL && cmsgtype == SCM_CREDS) 2825 for (n = control, n_prev = NULL; n != NULL;) { 2826 cm = mtod(n, struct cmsghdr *); 2827 if (cm->cmsg_level == SOL_SOCKET && 2828 cm->cmsg_type == SCM_CREDS) { 2829 if (n_prev == NULL) 2830 control = n->m_next; 2831 else 2832 n_prev->m_next = n->m_next; 2833 if (space != NULL) { 2834 MPASS(*space >= n->m_len); 2835 *space -= n->m_len; 2836 MPASS(*mbcnt >= MSIZE); 2837 *mbcnt -= MSIZE; 2838 if (n->m_flags & M_EXT) { 2839 MPASS(*mbcnt >= 2840 n->m_ext.ext_size); 2841 *mbcnt -= n->m_ext.ext_size; 2842 } 2843 MPASS(clast); 2844 if (*clast == n) { 2845 MPASS(n->m_next == NULL); 2846 if (n_prev == NULL) 2847 *clast = m; 2848 else 2849 *clast = n_prev; 2850 } 2851 } 2852 n = m_free(n); 2853 } else { 2854 n_prev = n; 2855 n = n->m_next; 2856 } 2857 } 2858 2859 /* Prepend it to the head. */ 2860 m->m_next = control; 2861 if (space != NULL) { 2862 *space += m->m_len; 2863 *mbcnt += MSIZE; 2864 if (control == NULL) 2865 *clast = m; 2866 } 2867 return (m); 2868 } 2869 2870 static struct unpcb * 2871 fptounp(struct file *fp) 2872 { 2873 struct socket *so; 2874 2875 if (fp->f_type != DTYPE_SOCKET) 2876 return (NULL); 2877 if ((so = fp->f_data) == NULL) 2878 return (NULL); 2879 if (so->so_proto->pr_domain != &localdomain) 2880 return (NULL); 2881 return sotounpcb(so); 2882 } 2883 2884 static void 2885 unp_discard(struct file *fp) 2886 { 2887 struct unp_defer *dr; 2888 2889 if (unp_externalize_fp(fp)) { 2890 dr = malloc(sizeof(*dr), M_TEMP, M_WAITOK); 2891 dr->ud_fp = fp; 2892 UNP_DEFERRED_LOCK(); 2893 SLIST_INSERT_HEAD(&unp_defers, dr, ud_link); 2894 UNP_DEFERRED_UNLOCK(); 2895 atomic_add_int(&unp_defers_count, 1); 2896 taskqueue_enqueue(taskqueue_thread, &unp_defer_task); 2897 } else 2898 closef_nothread(fp); 2899 } 2900 2901 static void 2902 unp_process_defers(void *arg __unused, int pending) 2903 { 2904 struct unp_defer *dr; 2905 SLIST_HEAD(, unp_defer) drl; 2906 int count; 2907 2908 SLIST_INIT(&drl); 2909 for (;;) { 2910 UNP_DEFERRED_LOCK(); 2911 if (SLIST_FIRST(&unp_defers) == NULL) { 2912 UNP_DEFERRED_UNLOCK(); 2913 break; 2914 } 2915 SLIST_SWAP(&unp_defers, &drl, unp_defer); 2916 UNP_DEFERRED_UNLOCK(); 2917 count = 0; 2918 while ((dr = SLIST_FIRST(&drl)) != NULL) { 2919 SLIST_REMOVE_HEAD(&drl, ud_link); 2920 closef_nothread(dr->ud_fp); 2921 free(dr, M_TEMP); 2922 count++; 2923 } 2924 atomic_add_int(&unp_defers_count, -count); 2925 } 2926 } 2927 2928 static void 2929 unp_internalize_fp(struct file *fp) 2930 { 2931 struct unpcb *unp; 2932 2933 UNP_LINK_WLOCK(); 2934 if ((unp = fptounp(fp)) != NULL) { 2935 unp->unp_file = fp; 2936 unp->unp_msgcount++; 2937 } 2938 unp_rights++; 2939 UNP_LINK_WUNLOCK(); 2940 } 2941 2942 static int 2943 unp_externalize_fp(struct file *fp) 2944 { 2945 struct unpcb *unp; 2946 int ret; 2947 2948 UNP_LINK_WLOCK(); 2949 if ((unp = fptounp(fp)) != NULL) { 2950 unp->unp_msgcount--; 2951 ret = 1; 2952 } else 2953 ret = 0; 2954 unp_rights--; 2955 UNP_LINK_WUNLOCK(); 2956 return (ret); 2957 } 2958 2959 /* 2960 * unp_defer indicates whether additional work has been defered for a future 2961 * pass through unp_gc(). It is thread local and does not require explicit 2962 * synchronization. 2963 */ 2964 static int unp_marked; 2965 2966 static void 2967 unp_remove_dead_ref(struct filedescent **fdep, int fdcount) 2968 { 2969 struct unpcb *unp; 2970 struct file *fp; 2971 int i; 2972 2973 /* 2974 * This function can only be called from the gc task. 2975 */ 2976 KASSERT(taskqueue_member(taskqueue_thread, curthread) != 0, 2977 ("%s: not on gc callout", __func__)); 2978 UNP_LINK_LOCK_ASSERT(); 2979 2980 for (i = 0; i < fdcount; i++) { 2981 fp = fdep[i]->fde_file; 2982 if ((unp = fptounp(fp)) == NULL) 2983 continue; 2984 if ((unp->unp_gcflag & UNPGC_DEAD) == 0) 2985 continue; 2986 unp->unp_gcrefs--; 2987 } 2988 } 2989 2990 static void 2991 unp_restore_undead_ref(struct filedescent **fdep, int fdcount) 2992 { 2993 struct unpcb *unp; 2994 struct file *fp; 2995 int i; 2996 2997 /* 2998 * This function can only be called from the gc task. 2999 */ 3000 KASSERT(taskqueue_member(taskqueue_thread, curthread) != 0, 3001 ("%s: not on gc callout", __func__)); 3002 UNP_LINK_LOCK_ASSERT(); 3003 3004 for (i = 0; i < fdcount; i++) { 3005 fp = fdep[i]->fde_file; 3006 if ((unp = fptounp(fp)) == NULL) 3007 continue; 3008 if ((unp->unp_gcflag & UNPGC_DEAD) == 0) 3009 continue; 3010 unp->unp_gcrefs++; 3011 unp_marked++; 3012 } 3013 } 3014 3015 static void 3016 unp_scan_socket(struct socket *so, void (*op)(struct filedescent **, int)) 3017 { 3018 struct sockbuf *sb; 3019 3020 SOCK_LOCK_ASSERT(so); 3021 3022 if (sotounpcb(so)->unp_gcflag & UNPGC_IGNORE_RIGHTS) 3023 return; 3024 3025 SOCK_RECVBUF_LOCK(so); 3026 switch (so->so_type) { 3027 case SOCK_DGRAM: 3028 unp_scan(STAILQ_FIRST(&so->so_rcv.uxdg_mb), op); 3029 unp_scan(so->so_rcv.uxdg_peeked, op); 3030 TAILQ_FOREACH(sb, &so->so_rcv.uxdg_conns, uxdg_clist) 3031 unp_scan(STAILQ_FIRST(&sb->uxdg_mb), op); 3032 break; 3033 case SOCK_STREAM: 3034 case SOCK_SEQPACKET: 3035 unp_scan(so->so_rcv.sb_mb, op); 3036 break; 3037 } 3038 SOCK_RECVBUF_UNLOCK(so); 3039 } 3040 3041 static void 3042 unp_gc_scan(struct unpcb *unp, void (*op)(struct filedescent **, int)) 3043 { 3044 struct socket *so, *soa; 3045 3046 so = unp->unp_socket; 3047 SOCK_LOCK(so); 3048 if (SOLISTENING(so)) { 3049 /* 3050 * Mark all sockets in our accept queue. 3051 */ 3052 TAILQ_FOREACH(soa, &so->sol_comp, so_list) 3053 unp_scan_socket(soa, op); 3054 } else { 3055 /* 3056 * Mark all sockets we reference with RIGHTS. 3057 */ 3058 unp_scan_socket(so, op); 3059 } 3060 SOCK_UNLOCK(so); 3061 } 3062 3063 static int unp_recycled; 3064 SYSCTL_INT(_net_local, OID_AUTO, recycled, CTLFLAG_RD, &unp_recycled, 0, 3065 "Number of unreachable sockets claimed by the garbage collector."); 3066 3067 static int unp_taskcount; 3068 SYSCTL_INT(_net_local, OID_AUTO, taskcount, CTLFLAG_RD, &unp_taskcount, 0, 3069 "Number of times the garbage collector has run."); 3070 3071 SYSCTL_UINT(_net_local, OID_AUTO, sockcount, CTLFLAG_RD, &unp_count, 0, 3072 "Number of active local sockets."); 3073 3074 static void 3075 unp_gc(__unused void *arg, int pending) 3076 { 3077 struct unp_head *heads[] = { &unp_dhead, &unp_shead, &unp_sphead, 3078 NULL }; 3079 struct unp_head **head; 3080 struct unp_head unp_deadhead; /* List of potentially-dead sockets. */ 3081 struct file *f, **unref; 3082 struct unpcb *unp, *unptmp; 3083 int i, total, unp_unreachable; 3084 3085 LIST_INIT(&unp_deadhead); 3086 unp_taskcount++; 3087 UNP_LINK_RLOCK(); 3088 /* 3089 * First determine which sockets may be in cycles. 3090 */ 3091 unp_unreachable = 0; 3092 3093 for (head = heads; *head != NULL; head++) 3094 LIST_FOREACH(unp, *head, unp_link) { 3095 KASSERT((unp->unp_gcflag & ~UNPGC_IGNORE_RIGHTS) == 0, 3096 ("%s: unp %p has unexpected gc flags 0x%x", 3097 __func__, unp, (unsigned int)unp->unp_gcflag)); 3098 3099 f = unp->unp_file; 3100 3101 /* 3102 * Check for an unreachable socket potentially in a 3103 * cycle. It must be in a queue as indicated by 3104 * msgcount, and this must equal the file reference 3105 * count. Note that when msgcount is 0 the file is 3106 * NULL. 3107 */ 3108 if (f != NULL && unp->unp_msgcount != 0 && 3109 refcount_load(&f->f_count) == unp->unp_msgcount) { 3110 LIST_INSERT_HEAD(&unp_deadhead, unp, unp_dead); 3111 unp->unp_gcflag |= UNPGC_DEAD; 3112 unp->unp_gcrefs = unp->unp_msgcount; 3113 unp_unreachable++; 3114 } 3115 } 3116 3117 /* 3118 * Scan all sockets previously marked as potentially being in a cycle 3119 * and remove the references each socket holds on any UNPGC_DEAD 3120 * sockets in its queue. After this step, all remaining references on 3121 * sockets marked UNPGC_DEAD should not be part of any cycle. 3122 */ 3123 LIST_FOREACH(unp, &unp_deadhead, unp_dead) 3124 unp_gc_scan(unp, unp_remove_dead_ref); 3125 3126 /* 3127 * If a socket still has a non-negative refcount, it cannot be in a 3128 * cycle. In this case increment refcount of all children iteratively. 3129 * Stop the scan once we do a complete loop without discovering 3130 * a new reachable socket. 3131 */ 3132 do { 3133 unp_marked = 0; 3134 LIST_FOREACH_SAFE(unp, &unp_deadhead, unp_dead, unptmp) 3135 if (unp->unp_gcrefs > 0) { 3136 unp->unp_gcflag &= ~UNPGC_DEAD; 3137 LIST_REMOVE(unp, unp_dead); 3138 KASSERT(unp_unreachable > 0, 3139 ("%s: unp_unreachable underflow.", 3140 __func__)); 3141 unp_unreachable--; 3142 unp_gc_scan(unp, unp_restore_undead_ref); 3143 } 3144 } while (unp_marked); 3145 3146 UNP_LINK_RUNLOCK(); 3147 3148 if (unp_unreachable == 0) 3149 return; 3150 3151 /* 3152 * Allocate space for a local array of dead unpcbs. 3153 * TODO: can this path be simplified by instead using the local 3154 * dead list at unp_deadhead, after taking out references 3155 * on the file object and/or unpcb and dropping the link lock? 3156 */ 3157 unref = malloc(unp_unreachable * sizeof(struct file *), 3158 M_TEMP, M_WAITOK); 3159 3160 /* 3161 * Iterate looking for sockets which have been specifically marked 3162 * as unreachable and store them locally. 3163 */ 3164 UNP_LINK_RLOCK(); 3165 total = 0; 3166 LIST_FOREACH(unp, &unp_deadhead, unp_dead) { 3167 KASSERT((unp->unp_gcflag & UNPGC_DEAD) != 0, 3168 ("%s: unp %p not marked UNPGC_DEAD", __func__, unp)); 3169 unp->unp_gcflag &= ~UNPGC_DEAD; 3170 f = unp->unp_file; 3171 if (unp->unp_msgcount == 0 || f == NULL || 3172 refcount_load(&f->f_count) != unp->unp_msgcount || 3173 !fhold(f)) 3174 continue; 3175 unref[total++] = f; 3176 KASSERT(total <= unp_unreachable, 3177 ("%s: incorrect unreachable count.", __func__)); 3178 } 3179 UNP_LINK_RUNLOCK(); 3180 3181 /* 3182 * Now flush all sockets, free'ing rights. This will free the 3183 * struct files associated with these sockets but leave each socket 3184 * with one remaining ref. 3185 */ 3186 for (i = 0; i < total; i++) { 3187 struct socket *so; 3188 3189 so = unref[i]->f_data; 3190 CURVNET_SET(so->so_vnet); 3191 socantrcvmore(so); 3192 unp_dispose(so); 3193 CURVNET_RESTORE(); 3194 } 3195 3196 /* 3197 * And finally release the sockets so they can be reclaimed. 3198 */ 3199 for (i = 0; i < total; i++) 3200 fdrop(unref[i], NULL); 3201 unp_recycled += total; 3202 free(unref, M_TEMP); 3203 } 3204 3205 /* 3206 * Synchronize against unp_gc, which can trip over data as we are freeing it. 3207 */ 3208 static void 3209 unp_dispose(struct socket *so) 3210 { 3211 struct sockbuf *sb; 3212 struct unpcb *unp; 3213 struct mbuf *m; 3214 int error __diagused; 3215 3216 MPASS(!SOLISTENING(so)); 3217 3218 unp = sotounpcb(so); 3219 UNP_LINK_WLOCK(); 3220 unp->unp_gcflag |= UNPGC_IGNORE_RIGHTS; 3221 UNP_LINK_WUNLOCK(); 3222 3223 /* 3224 * Grab our special mbufs before calling sbrelease(). 3225 */ 3226 error = SOCK_IO_RECV_LOCK(so, SBL_WAIT | SBL_NOINTR); 3227 MPASS(!error); 3228 SOCK_RECVBUF_LOCK(so); 3229 switch (so->so_type) { 3230 case SOCK_DGRAM: 3231 while ((sb = TAILQ_FIRST(&so->so_rcv.uxdg_conns)) != NULL) { 3232 STAILQ_CONCAT(&so->so_rcv.uxdg_mb, &sb->uxdg_mb); 3233 TAILQ_REMOVE(&so->so_rcv.uxdg_conns, sb, uxdg_clist); 3234 /* Note: socket of sb may reconnect. */ 3235 sb->uxdg_cc = sb->uxdg_ctl = sb->uxdg_mbcnt = 0; 3236 } 3237 sb = &so->so_rcv; 3238 if (sb->uxdg_peeked != NULL) { 3239 STAILQ_INSERT_HEAD(&sb->uxdg_mb, sb->uxdg_peeked, 3240 m_stailqpkt); 3241 sb->uxdg_peeked = NULL; 3242 } 3243 m = STAILQ_FIRST(&sb->uxdg_mb); 3244 STAILQ_INIT(&sb->uxdg_mb); 3245 /* XXX: our shortened sbrelease() */ 3246 (void)chgsbsize(so->so_cred->cr_uidinfo, &sb->sb_hiwat, 0, 3247 RLIM_INFINITY); 3248 /* 3249 * XXXGL Mark sb with SBS_CANTRCVMORE. This is needed to 3250 * prevent uipc_sosend_dgram() or unp_disconnect() adding more 3251 * data to the socket. 3252 * We came here either through shutdown(2) or from the final 3253 * sofree(). The sofree() case is simple as it guarantees 3254 * that no more sends will happen, however we can race with 3255 * unp_disconnect() from our peer. The shutdown(2) case is 3256 * more exotic. It would call into unp_dispose() only if 3257 * socket is SS_ISCONNECTED. This is possible if we did 3258 * connect(2) on this socket and we also had it bound with 3259 * bind(2) and receive connections from other sockets. 3260 * Because uipc_shutdown() violates POSIX (see comment 3261 * there) we will end up here shutting down our receive side. 3262 * Of course this will have affect not only on the peer we 3263 * connect(2)ed to, but also on all of the peers who had 3264 * connect(2)ed to us. Their sends would end up with ENOBUFS. 3265 */ 3266 sb->sb_state |= SBS_CANTRCVMORE; 3267 break; 3268 case SOCK_STREAM: 3269 case SOCK_SEQPACKET: 3270 sb = &so->so_rcv; 3271 m = sbcut_locked(sb, sb->sb_ccc); 3272 KASSERT(sb->sb_ccc == 0 && sb->sb_mb == 0 && sb->sb_mbcnt == 0, 3273 ("%s: ccc %u mb %p mbcnt %u", __func__, 3274 sb->sb_ccc, (void *)sb->sb_mb, sb->sb_mbcnt)); 3275 sbrelease_locked(so, SO_RCV); 3276 break; 3277 } 3278 SOCK_RECVBUF_UNLOCK(so); 3279 SOCK_IO_RECV_UNLOCK(so); 3280 3281 if (m != NULL) { 3282 unp_scan(m, unp_freerights); 3283 m_freem(m); 3284 } 3285 } 3286 3287 static void 3288 unp_scan(struct mbuf *m0, void (*op)(struct filedescent **, int)) 3289 { 3290 struct mbuf *m; 3291 struct cmsghdr *cm; 3292 void *data; 3293 socklen_t clen, datalen; 3294 3295 while (m0 != NULL) { 3296 for (m = m0; m; m = m->m_next) { 3297 if (m->m_type != MT_CONTROL) 3298 continue; 3299 3300 cm = mtod(m, struct cmsghdr *); 3301 clen = m->m_len; 3302 3303 while (cm != NULL) { 3304 if (sizeof(*cm) > clen || cm->cmsg_len > clen) 3305 break; 3306 3307 data = CMSG_DATA(cm); 3308 datalen = (caddr_t)cm + cm->cmsg_len 3309 - (caddr_t)data; 3310 3311 if (cm->cmsg_level == SOL_SOCKET && 3312 cm->cmsg_type == SCM_RIGHTS) { 3313 (*op)(data, datalen / 3314 sizeof(struct filedescent *)); 3315 } 3316 3317 if (CMSG_SPACE(datalen) < clen) { 3318 clen -= CMSG_SPACE(datalen); 3319 cm = (struct cmsghdr *) 3320 ((caddr_t)cm + CMSG_SPACE(datalen)); 3321 } else { 3322 clen = 0; 3323 cm = NULL; 3324 } 3325 } 3326 } 3327 m0 = m0->m_nextpkt; 3328 } 3329 } 3330 3331 /* 3332 * Definitions of protocols supported in the LOCAL domain. 3333 */ 3334 static struct protosw streamproto = { 3335 .pr_type = SOCK_STREAM, 3336 .pr_flags = PR_CONNREQUIRED | PR_WANTRCVD | PR_CAPATTACH, 3337 .pr_ctloutput = &uipc_ctloutput, 3338 .pr_abort = uipc_abort, 3339 .pr_accept = uipc_peeraddr, 3340 .pr_attach = uipc_attach, 3341 .pr_bind = uipc_bind, 3342 .pr_bindat = uipc_bindat, 3343 .pr_connect = uipc_connect, 3344 .pr_connectat = uipc_connectat, 3345 .pr_connect2 = uipc_connect2, 3346 .pr_detach = uipc_detach, 3347 .pr_disconnect = uipc_disconnect, 3348 .pr_listen = uipc_listen, 3349 .pr_peeraddr = uipc_peeraddr, 3350 .pr_rcvd = uipc_rcvd, 3351 .pr_send = uipc_send, 3352 .pr_ready = uipc_ready, 3353 .pr_sense = uipc_sense, 3354 .pr_shutdown = uipc_shutdown, 3355 .pr_sockaddr = uipc_sockaddr, 3356 .pr_soreceive = soreceive_generic, 3357 .pr_close = uipc_close, 3358 }; 3359 3360 static struct protosw dgramproto = { 3361 .pr_type = SOCK_DGRAM, 3362 .pr_flags = PR_ATOMIC | PR_ADDR | PR_CAPATTACH | PR_SOCKBUF, 3363 .pr_ctloutput = &uipc_ctloutput, 3364 .pr_abort = uipc_abort, 3365 .pr_accept = uipc_peeraddr, 3366 .pr_attach = uipc_attach, 3367 .pr_bind = uipc_bind, 3368 .pr_bindat = uipc_bindat, 3369 .pr_connect = uipc_connect, 3370 .pr_connectat = uipc_connectat, 3371 .pr_connect2 = uipc_connect2, 3372 .pr_detach = uipc_detach, 3373 .pr_disconnect = uipc_disconnect, 3374 .pr_peeraddr = uipc_peeraddr, 3375 .pr_sosend = uipc_sosend_dgram, 3376 .pr_sense = uipc_sense, 3377 .pr_shutdown = uipc_shutdown, 3378 .pr_sockaddr = uipc_sockaddr, 3379 .pr_soreceive = uipc_soreceive_dgram, 3380 .pr_close = uipc_close, 3381 }; 3382 3383 static struct protosw seqpacketproto = { 3384 .pr_type = SOCK_SEQPACKET, 3385 /* 3386 * XXXRW: For now, PR_ADDR because soreceive will bump into them 3387 * due to our use of sbappendaddr. A new sbappend variants is needed 3388 * that supports both atomic record writes and control data. 3389 */ 3390 .pr_flags = PR_ADDR | PR_ATOMIC | PR_CONNREQUIRED | 3391 PR_WANTRCVD | PR_CAPATTACH, 3392 .pr_ctloutput = &uipc_ctloutput, 3393 .pr_abort = uipc_abort, 3394 .pr_accept = uipc_peeraddr, 3395 .pr_attach = uipc_attach, 3396 .pr_bind = uipc_bind, 3397 .pr_bindat = uipc_bindat, 3398 .pr_connect = uipc_connect, 3399 .pr_connectat = uipc_connectat, 3400 .pr_connect2 = uipc_connect2, 3401 .pr_detach = uipc_detach, 3402 .pr_disconnect = uipc_disconnect, 3403 .pr_listen = uipc_listen, 3404 .pr_peeraddr = uipc_peeraddr, 3405 .pr_rcvd = uipc_rcvd, 3406 .pr_send = uipc_send, 3407 .pr_sense = uipc_sense, 3408 .pr_shutdown = uipc_shutdown, 3409 .pr_sockaddr = uipc_sockaddr, 3410 .pr_soreceive = soreceive_generic, /* XXX: or...? */ 3411 .pr_close = uipc_close, 3412 }; 3413 3414 static struct domain localdomain = { 3415 .dom_family = AF_LOCAL, 3416 .dom_name = "local", 3417 .dom_externalize = unp_externalize, 3418 .dom_nprotosw = 3, 3419 .dom_protosw = { 3420 &streamproto, 3421 &dgramproto, 3422 &seqpacketproto, 3423 } 3424 }; 3425 DOMAIN_SET(local); 3426 3427 /* 3428 * A helper function called by VFS before socket-type vnode reclamation. 3429 * For an active vnode it clears unp_vnode pointer and decrements unp_vnode 3430 * use count. 3431 */ 3432 void 3433 vfs_unp_reclaim(struct vnode *vp) 3434 { 3435 struct unpcb *unp; 3436 int active; 3437 struct mtx *vplock; 3438 3439 ASSERT_VOP_ELOCKED(vp, "vfs_unp_reclaim"); 3440 KASSERT(vp->v_type == VSOCK, 3441 ("vfs_unp_reclaim: vp->v_type != VSOCK")); 3442 3443 active = 0; 3444 vplock = mtx_pool_find(mtxpool_sleep, vp); 3445 mtx_lock(vplock); 3446 VOP_UNP_CONNECT(vp, &unp); 3447 if (unp == NULL) 3448 goto done; 3449 UNP_PCB_LOCK(unp); 3450 if (unp->unp_vnode == vp) { 3451 VOP_UNP_DETACH(vp); 3452 unp->unp_vnode = NULL; 3453 active = 1; 3454 } 3455 UNP_PCB_UNLOCK(unp); 3456 done: 3457 mtx_unlock(vplock); 3458 if (active) 3459 vunref(vp); 3460 } 3461 3462 #ifdef DDB 3463 static void 3464 db_print_indent(int indent) 3465 { 3466 int i; 3467 3468 for (i = 0; i < indent; i++) 3469 db_printf(" "); 3470 } 3471 3472 static void 3473 db_print_unpflags(int unp_flags) 3474 { 3475 int comma; 3476 3477 comma = 0; 3478 if (unp_flags & UNP_HAVEPC) { 3479 db_printf("%sUNP_HAVEPC", comma ? ", " : ""); 3480 comma = 1; 3481 } 3482 if (unp_flags & UNP_WANTCRED_ALWAYS) { 3483 db_printf("%sUNP_WANTCRED_ALWAYS", comma ? ", " : ""); 3484 comma = 1; 3485 } 3486 if (unp_flags & UNP_WANTCRED_ONESHOT) { 3487 db_printf("%sUNP_WANTCRED_ONESHOT", comma ? ", " : ""); 3488 comma = 1; 3489 } 3490 if (unp_flags & UNP_CONNECTING) { 3491 db_printf("%sUNP_CONNECTING", comma ? ", " : ""); 3492 comma = 1; 3493 } 3494 if (unp_flags & UNP_BINDING) { 3495 db_printf("%sUNP_BINDING", comma ? ", " : ""); 3496 comma = 1; 3497 } 3498 } 3499 3500 static void 3501 db_print_xucred(int indent, struct xucred *xu) 3502 { 3503 int comma, i; 3504 3505 db_print_indent(indent); 3506 db_printf("cr_version: %u cr_uid: %u cr_pid: %d cr_ngroups: %d\n", 3507 xu->cr_version, xu->cr_uid, xu->cr_pid, xu->cr_ngroups); 3508 db_print_indent(indent); 3509 db_printf("cr_groups: "); 3510 comma = 0; 3511 for (i = 0; i < xu->cr_ngroups; i++) { 3512 db_printf("%s%u", comma ? ", " : "", xu->cr_groups[i]); 3513 comma = 1; 3514 } 3515 db_printf("\n"); 3516 } 3517 3518 static void 3519 db_print_unprefs(int indent, struct unp_head *uh) 3520 { 3521 struct unpcb *unp; 3522 int counter; 3523 3524 counter = 0; 3525 LIST_FOREACH(unp, uh, unp_reflink) { 3526 if (counter % 4 == 0) 3527 db_print_indent(indent); 3528 db_printf("%p ", unp); 3529 if (counter % 4 == 3) 3530 db_printf("\n"); 3531 counter++; 3532 } 3533 if (counter != 0 && counter % 4 != 0) 3534 db_printf("\n"); 3535 } 3536 3537 DB_SHOW_COMMAND(unpcb, db_show_unpcb) 3538 { 3539 struct unpcb *unp; 3540 3541 if (!have_addr) { 3542 db_printf("usage: show unpcb <addr>\n"); 3543 return; 3544 } 3545 unp = (struct unpcb *)addr; 3546 3547 db_printf("unp_socket: %p unp_vnode: %p\n", unp->unp_socket, 3548 unp->unp_vnode); 3549 3550 db_printf("unp_ino: %ju unp_conn: %p\n", (uintmax_t)unp->unp_ino, 3551 unp->unp_conn); 3552 3553 db_printf("unp_refs:\n"); 3554 db_print_unprefs(2, &unp->unp_refs); 3555 3556 /* XXXRW: Would be nice to print the full address, if any. */ 3557 db_printf("unp_addr: %p\n", unp->unp_addr); 3558 3559 db_printf("unp_gencnt: %llu\n", 3560 (unsigned long long)unp->unp_gencnt); 3561 3562 db_printf("unp_flags: %x (", unp->unp_flags); 3563 db_print_unpflags(unp->unp_flags); 3564 db_printf(")\n"); 3565 3566 db_printf("unp_peercred:\n"); 3567 db_print_xucred(2, &unp->unp_peercred); 3568 3569 db_printf("unp_refcount: %u\n", unp->unp_refcount); 3570 } 3571 #endif 3572