sys/kern/uipc_usrreq.c

   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  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      From: @(#)uipc_usrreq.c 8.3 (Berkeley) 1/4/94
  34  */
  35
  36 /*
  37  * UNIX Domain (Local) Sockets
  38  *
  39  * This is an implementation of UNIX (local) domain sockets.  Each socket has
  40  * an associated struct unpcb (UNIX protocol control block).  Stream sockets
  41  * may be connected to 0 or 1 other socket.  Datagram sockets may be
  42  * connected to 0, 1, or many other sockets.  Sockets may be created and
  43  * connected in pairs (socketpair(2)), or bound/connected to using the file
  44  * system name space.  For most purposes, only the receive socket buffer is
  45  * used, as sending on one socket delivers directly to the receive socket
  46  * buffer of a second socket.
  47  *
  48  * The implementation is substantially complicated by the fact that
  49  * "ancillary data", such as file descriptors or credentials, may be passed
  50  * across UNIX domain sockets.  The potential for passing UNIX domain sockets
  51  * over other UNIX domain sockets requires the implementation of a simple
  52  * garbage collector to find and tear down cycles of disconnected sockets.
  53  *
  54  * TODO:
  55  *      RDM
  56  *      rethink name space problems
  57  *      need a proper out-of-band
  58  */
  59
  60 #include <sys/cdefs.h>
  61 __FBSDID("$FreeBSD$");
  62
  63 #include "opt_ddb.h"
  64
  65 #include <sys/param.h>
  66 #include <sys/capsicum.h>
  67 #include <sys/domain.h>
  68 #include <sys/fcntl.h>
  69 #include <sys/malloc.h>         /* XXX must be before <sys/file.h> */
  70 #include <sys/eventhandler.h>
  71 #include <sys/file.h>
  72 #include <sys/filedesc.h>
  73 #include <sys/kernel.h>
  74 #include <sys/lock.h>
  75 #include <sys/mbuf.h>
  76 #include <sys/mount.h>
  77 #include <sys/mutex.h>
  78 #include <sys/namei.h>
  79 #include <sys/proc.h>
  80 #include <sys/protosw.h>
  81 #include <sys/queue.h>
  82 #include <sys/resourcevar.h>
  83 #include <sys/rwlock.h>
  84 #include <sys/socket.h>
  85 #include <sys/socketvar.h>
  86 #include <sys/signalvar.h>
  87 #include <sys/stat.h>
  88 #include <sys/sx.h>
  89 #include <sys/sysctl.h>
  90 #include <sys/systm.h>
  91 #include <sys/taskqueue.h>
  92 #include <sys/un.h>
  93 #include <sys/unpcb.h>
  94 #include <sys/vnode.h>
  95
  96 #include <net/vnet.h>
  97
  98 #ifdef DDB
  99 #include <ddb/ddb.h>
 100 #endif
 101
 102 #include <security/mac/mac_framework.h>
 103
 104 #include <vm/uma.h>
 105
 106 MALLOC_DECLARE(M_FILECAPS);
 107
 108 /*
 109  * Locking key:
 110  * (l)  Locked using list lock
 111  * (g)  Locked using linkage lock
 112  */
 113
 114 static uma_zone_t       unp_zone;
 115 static unp_gen_t        unp_gencnt;     /* (l) */
 116 static u_int            unp_count;      /* (l) Count of local sockets. */
 117 static ino_t            unp_ino;        /* Prototype for fake inode numbers. */
 118 static int              unp_rights;     /* (g) File descriptors in flight. */
 119 static struct unp_head  unp_shead;      /* (l) List of stream sockets. */
 120 static struct unp_head  unp_dhead;      /* (l) List of datagram sockets. */
 121 static struct unp_head  unp_sphead;     /* (l) List of seqpacket sockets. */
 122
 123 struct unp_defer {
 124         SLIST_ENTRY(unp_defer) ud_link;
 125         struct file *ud_fp;
 126 };
 127 static SLIST_HEAD(, unp_defer) unp_defers;
 128 static int unp_defers_count;
 129
 130 static const struct sockaddr    sun_noname = { sizeof(sun_noname), AF_LOCAL };
 131
 132 /*
 133  * Garbage collection of cyclic file descriptor/socket references occurs
 134  * asynchronously in a taskqueue context in order to avoid recursion and
 135  * reentrance in the UNIX domain socket, file descriptor, and socket layer
 136  * code.  See unp_gc() for a full description.
 137  */
 138 static struct timeout_task unp_gc_task;
 139
 140 /*
 141  * The close of unix domain sockets attached as SCM_RIGHTS is
 142  * postponed to the taskqueue, to avoid arbitrary recursion depth.
 143  * The attached sockets might have another sockets attached.
 144  */
 145 static struct task      unp_defer_task;
 146
 147 /*
 148  * Both send and receive buffers are allocated PIPSIZ bytes of buffering for
 149  * stream sockets, although the total for sender and receiver is actually
 150  * only PIPSIZ.
 151  *
 152  * Datagram sockets really use the sendspace as the maximum datagram size,
 153  * and don't really want to reserve the sendspace.  Their recvspace should be
 154  * large enough for at least one max-size datagram plus address.
 155  */
 156 #ifndef PIPSIZ
 157 #define PIPSIZ  8192
 158 #endif
 159 static u_long   unpst_sendspace = PIPSIZ;
 160 static u_long   unpst_recvspace = PIPSIZ;
 161 static u_long   unpdg_sendspace = 2*1024;       /* really max datagram size */
 162 static u_long   unpdg_recvspace = 4*1024;
 163 static u_long   unpsp_sendspace = PIPSIZ;       /* really max datagram size */
 164 static u_long   unpsp_recvspace = PIPSIZ;
 165
 166 static SYSCTL_NODE(_net, PF_LOCAL, local, CTLFLAG_RW, 0, "Local domain");
 167 static SYSCTL_NODE(_net_local, SOCK_STREAM, stream, CTLFLAG_RW, 0,
 168     "SOCK_STREAM");
 169 static SYSCTL_NODE(_net_local, SOCK_DGRAM, dgram, CTLFLAG_RW, 0, "SOCK_DGRAM");
 170 static SYSCTL_NODE(_net_local, SOCK_SEQPACKET, seqpacket, CTLFLAG_RW, 0,
 171     "SOCK_SEQPACKET");
 172
 173 SYSCTL_ULONG(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW,
 174            &unpst_sendspace, 0, "Default stream send space.");
 175 SYSCTL_ULONG(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW,
 176            &unpst_recvspace, 0, "Default stream receive space.");
 177 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW,
 178            &unpdg_sendspace, 0, "Default datagram send space.");
 179 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW,
 180            &unpdg_recvspace, 0, "Default datagram receive space.");
 181 SYSCTL_ULONG(_net_local_seqpacket, OID_AUTO, maxseqpacket, CTLFLAG_RW,
 182            &unpsp_sendspace, 0, "Default seqpacket send space.");
 183 SYSCTL_ULONG(_net_local_seqpacket, OID_AUTO, recvspace, CTLFLAG_RW,
 184            &unpsp_recvspace, 0, "Default seqpacket receive space.");
 185 SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0,
 186     "File descriptors in flight.");
 187 SYSCTL_INT(_net_local, OID_AUTO, deferred, CTLFLAG_RD,
 188     &unp_defers_count, 0,
 189     "File descriptors deferred to taskqueue for close.");
 190
 191 /*
 192  * Locking and synchronization:
 193  *
 194  * Three types of locks exist in the local domain socket implementation: a
 195  * a global linkage rwlock, the mtxpool lock, and per-unpcb mutexes.
 196  * The linkage lock protects the socket count, global generation number,
 197  * and stream/datagram global lists.
 198  *
 199  * The mtxpool lock protects the vnode from being modified while referenced.
 200  * Lock ordering requires that it be acquired before any unpcb locks.
 201  *
 202  * The unpcb lock (unp_mtx) protects all fields in the unpcb. Of particular
 203  * note is that this includes the unp_conn field. So long as the unpcb lock
 204  * is held the reference to the unpcb pointed to by unp_conn is valid. If we
 205  * require that the unpcb pointed to by unp_conn remain live in cases where
 206  * we need to drop the unp_mtx as when we need to acquire the lock for a
 207  * second unpcb the caller must first acquire an additional reference on the
 208  * second unpcb and then revalidate any state (typically check that unp_conn
 209  * is non-NULL) upon requiring the initial unpcb lock. The lock ordering
 210  * between unpcbs is the conventional ascending address order. Two helper
 211  * routines exist for this:
 212  *
 213  *   - unp_pcb_lock2(unp, unp2) - which just acquires the two locks in the
 214  *     safe ordering.
 215  *
 216  *   - unp_pcb_owned_lock2(unp, unp2, freed) - the lock for unp is held
 217  *     when called. If unp is unlocked and unp2 is subsequently freed
 218  *     freed will be set to 1.
 219  *
 220  * The helper routines for references are:
 221  *
 222  *   - unp_pcb_hold(unp): Can be called any time we currently hold a valid
 223  *     reference to unp.
 224  *
 225  *    - unp_pcb_rele(unp): The caller must hold the unp lock. If we are
 226  *      releasing the last reference, detach must have been called thus
 227  *      unp->unp_socket be NULL.
 228  *
 229  * UNIX domain sockets each have an unpcb hung off of their so_pcb pointer,
 230  * allocated in pru_attach() and freed in pru_detach().  The validity of that
 231  * pointer is an invariant, so no lock is required to dereference the so_pcb
 232  * pointer if a valid socket reference is held by the caller.  In practice,
 233  * this is always true during operations performed on a socket.  Each unpcb
 234  * has a back-pointer to its socket, unp_socket, which will be stable under
 235  * the same circumstances.
 236  *
 237  * This pointer may only be safely dereferenced as long as a valid reference
 238  * to the unpcb is held.  Typically, this reference will be from the socket,
 239  * or from another unpcb when the referring unpcb's lock is held (in order
 240  * that the reference not be invalidated during use).  For example, to follow
 241  * unp->unp_conn->unp_socket, you need to hold a lock on unp_conn to guarantee
 242  * that detach is not run clearing unp_socket.
 243  *
 244  * Blocking with UNIX domain sockets is a tricky issue: unlike most network
 245  * protocols, bind() is a non-atomic operation, and connect() requires
 246  * potential sleeping in the protocol, due to potentially waiting on local or
 247  * distributed file systems.  We try to separate "lookup" operations, which
 248  * may sleep, and the IPC operations themselves, which typically can occur
 249  * with relative atomicity as locks can be held over the entire operation.
 250  *
 251  * Another tricky issue is simultaneous multi-threaded or multi-process
 252  * access to a single UNIX domain socket.  These are handled by the flags
 253  * UNP_CONNECTING and UNP_BINDING, which prevent concurrent connecting or
 254  * binding, both of which involve dropping UNIX domain socket locks in order
 255  * to perform namei() and other file system operations.
 256  */
 257 static struct rwlock    unp_link_rwlock;
 258 static struct mtx       unp_defers_lock;
 259
 260 #define UNP_LINK_LOCK_INIT()            rw_init(&unp_link_rwlock,       \
 261                                             "unp_link_rwlock")
 262
 263 #define UNP_LINK_LOCK_ASSERT()  rw_assert(&unp_link_rwlock,     \
 264                                             RA_LOCKED)
 265 #define UNP_LINK_UNLOCK_ASSERT()        rw_assert(&unp_link_rwlock,     \
 266                                             RA_UNLOCKED)
 267
 268 #define UNP_LINK_RLOCK()                rw_rlock(&unp_link_rwlock)
 269 #define UNP_LINK_RUNLOCK()              rw_runlock(&unp_link_rwlock)
 270 #define UNP_LINK_WLOCK()                rw_wlock(&unp_link_rwlock)
 271 #define UNP_LINK_WUNLOCK()              rw_wunlock(&unp_link_rwlock)
 272 #define UNP_LINK_WLOCK_ASSERT()         rw_assert(&unp_link_rwlock,     \
 273                                             RA_WLOCKED)
 274 #define UNP_LINK_WOWNED()               rw_wowned(&unp_link_rwlock)
 275
 276 #define UNP_DEFERRED_LOCK_INIT()        mtx_init(&unp_defers_lock, \
 277                                             "unp_defer", NULL, MTX_DEF)
 278 #define UNP_DEFERRED_LOCK()             mtx_lock(&unp_defers_lock)
 279 #define UNP_DEFERRED_UNLOCK()           mtx_unlock(&unp_defers_lock)
 280
 281 #define UNP_REF_LIST_LOCK()             UNP_DEFERRED_LOCK();
 282 #define UNP_REF_LIST_UNLOCK()           UNP_DEFERRED_UNLOCK();
 283
 284 #define UNP_PCB_LOCK_INIT(unp)          mtx_init(&(unp)->unp_mtx,       \
 285                                             "unp", "unp",       \
 286                                             MTX_DUPOK|MTX_DEF)
 287 #define UNP_PCB_LOCK_DESTROY(unp)       mtx_destroy(&(unp)->unp_mtx)
 288 #define UNP_PCB_LOCK(unp)               mtx_lock(&(unp)->unp_mtx)
 289 #define UNP_PCB_TRYLOCK(unp)            mtx_trylock(&(unp)->unp_mtx)
 290 #define UNP_PCB_UNLOCK(unp)             mtx_unlock(&(unp)->unp_mtx)
 291 #define UNP_PCB_OWNED(unp)              mtx_owned(&(unp)->unp_mtx)
 292 #define UNP_PCB_LOCK_ASSERT(unp)        mtx_assert(&(unp)->unp_mtx, MA_OWNED)
 293 #define UNP_PCB_UNLOCK_ASSERT(unp)      mtx_assert(&(unp)->unp_mtx, MA_NOTOWNED)
 294
 295 static int      uipc_connect2(struct socket *, struct socket *);
 296 static int      uipc_ctloutput(struct socket *, struct sockopt *);
 297 static int      unp_connect(struct socket *, struct sockaddr *,
 298                     struct thread *);
 299 static int      unp_connectat(int, struct socket *, struct sockaddr *,
 300                     struct thread *);
 301 static int      unp_connect2(struct socket *so, struct socket *so2, int);
 302 static void     unp_disconnect(struct unpcb *unp, struct unpcb *unp2);
 303 static void     unp_dispose(struct socket *so);
 304 static void     unp_dispose_mbuf(struct mbuf *);
 305 static void     unp_shutdown(struct unpcb *);
 306 static void     unp_drop(struct unpcb *);
 307 static void     unp_gc(__unused void *, int);
 308 static void     unp_scan(struct mbuf *, void (*)(struct filedescent **, int));
 309 static void     unp_discard(struct file *);
 310 static void     unp_freerights(struct filedescent **, int);
 311 static void     unp_init(void);
 312 static int      unp_internalize(struct mbuf **, struct thread *);
 313 static void     unp_internalize_fp(struct file *);
 314 static int      unp_externalize(struct mbuf *, struct mbuf **, int);
 315 static int      unp_externalize_fp(struct file *);
 316 static struct mbuf      *unp_addsockcred(struct thread *, struct mbuf *);
 317 static void     unp_process_defers(void * __unused, int);
 318
 319
 320 static void
 321 unp_pcb_hold(struct unpcb *unp)
 322 {
 323         MPASS(unp->unp_refcount);
 324         refcount_acquire(&unp->unp_refcount);
 325 }
 326
 327 static int
 328 unp_pcb_rele(struct unpcb *unp)
 329 {
 330         int freed;
 331
 332         UNP_PCB_LOCK_ASSERT(unp);
 333         MPASS(unp->unp_refcount);
 334         if ((freed = refcount_release(&unp->unp_refcount))) {
 335                 /* we got here with having detached? */
 336                 MPASS(unp->unp_socket == NULL);
 337                 UNP_PCB_UNLOCK(unp);
 338                 UNP_PCB_LOCK_DESTROY(unp);
 339                 uma_zfree(unp_zone, unp);
 340         }
 341         return (freed);
 342 }
 343
 344 static void
 345 unp_pcb_lock2(struct unpcb *unp, struct unpcb *unp2)
 346 {
 347         MPASS(unp != unp2);
 348         UNP_PCB_UNLOCK_ASSERT(unp);
 349         UNP_PCB_UNLOCK_ASSERT(unp2);
 350         if ((uintptr_t)unp2 > (uintptr_t)unp) {
 351                 UNP_PCB_LOCK(unp);
 352                 UNP_PCB_LOCK(unp2);
 353         } else {
 354                 UNP_PCB_LOCK(unp2);
 355                 UNP_PCB_LOCK(unp);
 356         }
 357 }
 358
 359 static __noinline void
 360 unp_pcb_owned_lock2_slowpath(struct unpcb *unp, struct unpcb **unp2p, int *freed)
 361
 362 {
 363         struct unpcb *unp2;
 364
 365         unp2 = *unp2p;
 366         unp_pcb_hold((unp2));
 367         UNP_PCB_UNLOCK((unp));
 368         UNP_PCB_LOCK((unp2));
 369         UNP_PCB_LOCK((unp));
 370         *freed = unp_pcb_rele((unp2));
 371         if (*freed)
 372                 *unp2p = NULL;
 373 }
 374
 375 #define unp_pcb_owned_lock2(unp, unp2, freed) do {                                      \
 376                 freed = 0;                                                                                                      \
 377                 UNP_PCB_LOCK_ASSERT((unp));                                                                     \
 378                 UNP_PCB_UNLOCK_ASSERT((unp2));                                                          \
 379                 MPASS(unp != unp2);                                                                                     \
 380                 if (__predict_true(UNP_PCB_TRYLOCK((unp2))))                            \
 381                         break;                                                                                                  \
 382                 else if ((uintptr_t)(unp2) > (uintptr_t)(unp))                          \
 383                         UNP_PCB_LOCK((unp2));                                                                   \
 384                 else {                                                                                                          \
 385                         unp_pcb_owned_lock2_slowpath((unp), &(unp2), &freed);   \
 386                 }                                                                                                                       \
 387 } while (0)
 388
 389
 390 /*
 391  * Definitions of protocols supported in the LOCAL domain.
 392  */
 393 static struct domain localdomain;
 394 static struct pr_usrreqs uipc_usrreqs_dgram, uipc_usrreqs_stream;
 395 static struct pr_usrreqs uipc_usrreqs_seqpacket;
 396 static struct protosw localsw[] = {
 397 {
 398         .pr_type =              SOCK_STREAM,
 399         .pr_domain =            &localdomain,
 400         .pr_flags =             PR_CONNREQUIRED|PR_WANTRCVD|PR_RIGHTS,
 401         .pr_ctloutput =         &uipc_ctloutput,
 402         .pr_usrreqs =           &uipc_usrreqs_stream
 403 },
 404 {
 405         .pr_type =              SOCK_DGRAM,
 406         .pr_domain =            &localdomain,
 407         .pr_flags =             PR_ATOMIC|PR_ADDR|PR_RIGHTS,
 408         .pr_ctloutput =         &uipc_ctloutput,
 409         .pr_usrreqs =           &uipc_usrreqs_dgram
 410 },
 411 {
 412         .pr_type =              SOCK_SEQPACKET,
 413         .pr_domain =            &localdomain,
 414
 415         /*
 416          * XXXRW: For now, PR_ADDR because soreceive will bump into them
 417          * due to our use of sbappendaddr.  A new sbappend variants is needed
 418          * that supports both atomic record writes and control data.
 419          */
 420         .pr_flags =             PR_ADDR|PR_ATOMIC|PR_CONNREQUIRED|PR_WANTRCVD|
 421                                     PR_RIGHTS,
 422         .pr_ctloutput =         &uipc_ctloutput,
 423         .pr_usrreqs =           &uipc_usrreqs_seqpacket,
 424 },
 425 };
 426
 427 static struct domain localdomain = {
 428         .dom_family =           AF_LOCAL,
 429         .dom_name =             "local",
 430         .dom_init =             unp_init,
 431         .dom_externalize =      unp_externalize,
 432         .dom_dispose =          unp_dispose,
 433         .dom_protosw =          localsw,
 434         .dom_protoswNPROTOSW =  &localsw[nitems(localsw)]
 435 };
 436 DOMAIN_SET(local);
 437
 438 static void
 439 uipc_abort(struct socket *so)
 440 {
 441         struct unpcb *unp, *unp2;
 442
 443         unp = sotounpcb(so);
 444         KASSERT(unp != NULL, ("uipc_abort: unp == NULL"));
 445         UNP_PCB_UNLOCK_ASSERT(unp);
 446
 447         UNP_PCB_LOCK(unp);
 448         unp2 = unp->unp_conn;
 449         if (unp2 != NULL) {
 450                 unp_pcb_hold(unp2);
 451                 UNP_PCB_UNLOCK(unp);
 452                 unp_drop(unp2);
 453         } else
 454                 UNP_PCB_UNLOCK(unp);
 455 }
 456
 457 static int
 458 uipc_accept(struct socket *so, struct sockaddr **nam)
 459 {
 460         struct unpcb *unp, *unp2;
 461         const struct sockaddr *sa;
 462
 463         /*
 464          * Pass back name of connected socket, if it was bound and we are
 465          * still connected (our peer may have closed already!).
 466          */
 467         unp = sotounpcb(so);
 468         KASSERT(unp != NULL, ("uipc_accept: unp == NULL"));
 469
 470         *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
 471         UNP_LINK_RLOCK();
 472         unp2 = unp->unp_conn;
 473         if (unp2 != NULL && unp2->unp_addr != NULL) {
 474                 UNP_PCB_LOCK(unp2);
 475                 sa = (struct sockaddr *) unp2->unp_addr;
 476                 bcopy(sa, *nam, sa->sa_len);
 477                 UNP_PCB_UNLOCK(unp2);
 478         } else {
 479                 sa = &sun_noname;
 480                 bcopy(sa, *nam, sa->sa_len);
 481         }
 482         UNP_LINK_RUNLOCK();
 483         return (0);
 484 }
 485
 486 static int
 487 uipc_attach(struct socket *so, int proto, struct thread *td)
 488 {
 489         u_long sendspace, recvspace;
 490         struct unpcb *unp;
 491         int error;
 492         bool locked;
 493
 494         KASSERT(so->so_pcb == NULL, ("uipc_attach: so_pcb != NULL"));
 495         if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
 496                 switch (so->so_type) {
 497                 case SOCK_STREAM:
 498                         sendspace = unpst_sendspace;
 499                         recvspace = unpst_recvspace;
 500                         break;
 501
 502                 case SOCK_DGRAM:
 503                         sendspace = unpdg_sendspace;
 504                         recvspace = unpdg_recvspace;
 505                         break;
 506
 507                 case SOCK_SEQPACKET:
 508                         sendspace = unpsp_sendspace;
 509                         recvspace = unpsp_recvspace;
 510                         break;
 511
 512                 default:
 513                         panic("uipc_attach");
 514                 }
 515                 error = soreserve(so, sendspace, recvspace);
 516                 if (error)
 517                         return (error);
 518         }
 519         unp = uma_zalloc(unp_zone, M_NOWAIT | M_ZERO);
 520         if (unp == NULL)
 521                 return (ENOBUFS);
 522         LIST_INIT(&unp->unp_refs);
 523         UNP_PCB_LOCK_INIT(unp);
 524         unp->unp_socket = so;
 525         so->so_pcb = unp;
 526         unp->unp_refcount = 1;
 527         if (so->so_listen != NULL)
 528                 unp->unp_flags |= UNP_NASCENT;
 529
 530         if ((locked = UNP_LINK_WOWNED()) == false)
 531                 UNP_LINK_WLOCK();
 532
 533         unp->unp_gencnt = ++unp_gencnt;
 534         unp_count++;
 535         switch (so->so_type) {
 536         case SOCK_STREAM:
 537                 LIST_INSERT_HEAD(&unp_shead, unp, unp_link);
 538                 break;
 539
 540         case SOCK_DGRAM:
 541                 LIST_INSERT_HEAD(&unp_dhead, unp, unp_link);
 542                 break;
 543
 544         case SOCK_SEQPACKET:
 545                 LIST_INSERT_HEAD(&unp_sphead, unp, unp_link);
 546                 break;
 547
 548         default:
 549                 panic("uipc_attach");
 550         }
 551
 552         if (locked == false)
 553                 UNP_LINK_WUNLOCK();
 554
 555         return (0);
 556 }
 557
 558 static int
 559 uipc_bindat(int fd, struct socket *so, struct sockaddr *nam, struct thread *td)
 560 {
 561         struct sockaddr_un *soun = (struct sockaddr_un *)nam;
 562         struct vattr vattr;
 563         int error, namelen;
 564         struct nameidata nd;
 565         struct unpcb *unp;
 566         struct vnode *vp;
 567         struct mount *mp;
 568         cap_rights_t rights;
 569         char *buf;
 570
 571         if (nam->sa_family != AF_UNIX)
 572                 return (EAFNOSUPPORT);
 573
 574         unp = sotounpcb(so);
 575         KASSERT(unp != NULL, ("uipc_bind: unp == NULL"));
 576
 577         if (soun->sun_len > sizeof(struct sockaddr_un))
 578                 return (EINVAL);
 579         namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path);
 580         if (namelen <= 0)
 581                 return (EINVAL);
 582
 583         /*
 584          * We don't allow simultaneous bind() calls on a single UNIX domain
 585          * socket, so flag in-progress operations, and return an error if an
 586          * operation is already in progress.
 587          *
 588          * Historically, we have not allowed a socket to be rebound, so this
 589          * also returns an error.  Not allowing re-binding simplifies the
 590          * implementation and avoids a great many possible failure modes.
 591          */
 592         UNP_PCB_LOCK(unp);
 593         if (unp->unp_vnode != NULL) {
 594                 UNP_PCB_UNLOCK(unp);
 595                 return (EINVAL);
 596         }
 597         if (unp->unp_flags & UNP_BINDING) {
 598                 UNP_PCB_UNLOCK(unp);
 599                 return (EALREADY);
 600         }
 601         unp->unp_flags |= UNP_BINDING;
 602         UNP_PCB_UNLOCK(unp);
 603
 604         buf = malloc(namelen + 1, M_TEMP, M_WAITOK);
 605         bcopy(soun->sun_path, buf, namelen);
 606         buf[namelen] = 0;
 607
 608 restart:
 609         NDINIT_ATRIGHTS(&nd, CREATE, NOFOLLOW | LOCKPARENT | SAVENAME | NOCACHE,
 610             UIO_SYSSPACE, buf, fd, cap_rights_init(&rights, CAP_BINDAT), td);
 611 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
 612         error = namei(&nd);
 613         if (error)
 614                 goto error;
 615         vp = nd.ni_vp;
 616         if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) {
 617                 NDFREE(&nd, NDF_ONLY_PNBUF);
 618                 if (nd.ni_dvp == vp)
 619                         vrele(nd.ni_dvp);
 620                 else
 621                         vput(nd.ni_dvp);
 622                 if (vp != NULL) {
 623                         vrele(vp);
 624                         error = EADDRINUSE;
 625                         goto error;
 626                 }
 627                 error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH);
 628                 if (error)
 629                         goto error;
 630                 goto restart;
 631         }
 632         VATTR_NULL(&vattr);
 633         vattr.va_type = VSOCK;
 634         vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask);
 635 #ifdef MAC
 636         error = mac_vnode_check_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd,
 637             &vattr);
 638 #endif
 639         if (error == 0)
 640                 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
 641         NDFREE(&nd, NDF_ONLY_PNBUF);
 642         vput(nd.ni_dvp);
 643         if (error) {
 644                 vn_finished_write(mp);
 645                 goto error;
 646         }
 647         vp = nd.ni_vp;
 648         ASSERT_VOP_ELOCKED(vp, "uipc_bind");
 649         soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK);
 650
 651         UNP_PCB_LOCK(unp);
 652         VOP_UNP_BIND(vp, unp);
 653         unp->unp_vnode = vp;
 654         unp->unp_addr = soun;
 655         unp->unp_flags &= ~UNP_BINDING;
 656         UNP_PCB_UNLOCK(unp);
 657         VOP_UNLOCK(vp, 0);
 658         vn_finished_write(mp);
 659         free(buf, M_TEMP);
 660         return (0);
 661
 662 error:
 663         UNP_PCB_LOCK(unp);
 664         unp->unp_flags &= ~UNP_BINDING;
 665         UNP_PCB_UNLOCK(unp);
 666         free(buf, M_TEMP);
 667         return (error);
 668 }
 669
 670 static int
 671 uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
 672 {
 673
 674         return (uipc_bindat(AT_FDCWD, so, nam, td));
 675 }
 676
 677 static int
 678 uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
 679 {
 680         int error;
 681
 682         KASSERT(td == curthread, ("uipc_connect: td != curthread"));
 683         error = unp_connect(so, nam, td);
 684         return (error);
 685 }
 686
 687 static int
 688 uipc_connectat(int fd, struct socket *so, struct sockaddr *nam,
 689     struct thread *td)
 690 {
 691         int error;
 692
 693         KASSERT(td == curthread, ("uipc_connectat: td != curthread"));
 694         error = unp_connectat(fd, so, nam, td);
 695         return (error);
 696 }
 697
 698 static void
 699 uipc_close(struct socket *so)
 700 {
 701         struct unpcb *unp, *unp2;
 702         struct vnode *vp = NULL;
 703         struct mtx *vplock;
 704         int freed;
 705         unp = sotounpcb(so);
 706         KASSERT(unp != NULL, ("uipc_close: unp == NULL"));
 707
 708
 709         vplock = NULL;
 710         if ((vp = unp->unp_vnode) != NULL) {
 711                 vplock = mtx_pool_find(mtxpool_sleep, vp);
 712                 mtx_lock(vplock);
 713         }
 714         UNP_PCB_LOCK(unp);
 715         if (vp && unp->unp_vnode == NULL) {
 716                 mtx_unlock(vplock);
 717                 vp = NULL;
 718         }
 719         if (vp != NULL) {
 720                 VOP_UNP_DETACH(vp);
 721                 unp->unp_vnode = NULL;
 722         }
 723         unp2 = unp->unp_conn;
 724         unp_pcb_hold(unp);
 725         if (__predict_false(unp == unp2)) {
 726                 unp_disconnect(unp, unp2);
 727         } else if (unp2 != NULL) {
 728                 unp_pcb_hold(unp2);
 729                 unp_pcb_owned_lock2(unp, unp2, freed);
 730                 unp_disconnect(unp, unp2);
 731                 if (unp_pcb_rele(unp2) == 0)
 732                         UNP_PCB_UNLOCK(unp2);
 733         }
 734         if (unp_pcb_rele(unp) == 0)
 735                 UNP_PCB_UNLOCK(unp);
 736         if (vp) {
 737                 mtx_unlock(vplock);
 738                 vrele(vp);
 739         }
 740 }
 741
 742 static int
 743 uipc_connect2(struct socket *so1, struct socket *so2)
 744 {
 745         struct unpcb *unp, *unp2;
 746         int error;
 747
 748         unp = so1->so_pcb;
 749         KASSERT(unp != NULL, ("uipc_connect2: unp == NULL"));
 750         unp2 = so2->so_pcb;
 751         KASSERT(unp2 != NULL, ("uipc_connect2: unp2 == NULL"));
 752         if (unp != unp2)
 753                 unp_pcb_lock2(unp, unp2);
 754         else
 755                 UNP_PCB_LOCK(unp);
 756         error = unp_connect2(so1, so2, PRU_CONNECT2);
 757         if (unp != unp2)
 758                 UNP_PCB_UNLOCK(unp2);
 759         UNP_PCB_UNLOCK(unp);
 760         return (error);
 761 }
 762
 763 static void
 764 uipc_detach(struct socket *so)
 765 {
 766         struct unpcb *unp, *unp2;
 767         struct mtx *vplock;
 768         struct sockaddr_un *saved_unp_addr;
 769         struct vnode *vp;
 770         int freeunp, local_unp_rights;
 771
 772         unp = sotounpcb(so);
 773         KASSERT(unp != NULL, ("uipc_detach: unp == NULL"));
 774
 775         vp = NULL;
 776         vplock = NULL;
 777         local_unp_rights = 0;
 778
 779         UNP_LINK_WLOCK();
 780         LIST_REMOVE(unp, unp_link);
 781         unp->unp_gencnt = ++unp_gencnt;
 782         --unp_count;
 783         UNP_LINK_WUNLOCK();
 784
 785         UNP_PCB_UNLOCK_ASSERT(unp);
 786  restart:
 787         if ((vp = unp->unp_vnode) != NULL) {
 788                 vplock = mtx_pool_find(mtxpool_sleep, vp);
 789                 mtx_lock(vplock);
 790         }
 791         UNP_PCB_LOCK(unp);
 792         if (unp->unp_vnode != vp &&
 793                 unp->unp_vnode != NULL) {
 794                 if (vplock)
 795                         mtx_unlock(vplock);
 796                 UNP_PCB_UNLOCK(unp);
 797                 goto restart;
 798         }
 799         if ((unp->unp_flags & UNP_NASCENT) != 0) {
 800                 goto teardown;
 801         }
 802         if ((vp = unp->unp_vnode) != NULL) {
 803                 VOP_UNP_DETACH(vp);
 804                 unp->unp_vnode = NULL;
 805         }
 806         if (__predict_false(unp == unp->unp_conn)) {
 807                 unp_disconnect(unp, unp);
 808                 unp2 = NULL;
 809                 goto connect_self;
 810         }
 811         if ((unp2 = unp->unp_conn) != NULL) {
 812                 unp_pcb_owned_lock2(unp, unp2, freeunp);
 813                 if (freeunp)
 814                         unp2 = NULL;
 815         }
 816         unp_pcb_hold(unp);
 817         if (unp2 != NULL) {
 818                 unp_pcb_hold(unp2);
 819                 unp_disconnect(unp, unp2);
 820                 if (unp_pcb_rele(unp2) == 0)
 821                         UNP_PCB_UNLOCK(unp2);
 822         }
 823  connect_self:
 824         UNP_PCB_UNLOCK(unp);
 825         UNP_REF_LIST_LOCK();
 826         while (!LIST_EMPTY(&unp->unp_refs)) {
 827                 struct unpcb *ref = LIST_FIRST(&unp->unp_refs);
 828
 829                 unp_pcb_hold(ref);
 830                 UNP_REF_LIST_UNLOCK();
 831
 832                 MPASS(ref != unp);
 833                 UNP_PCB_UNLOCK_ASSERT(ref);
 834                 unp_drop(ref);
 835                 UNP_REF_LIST_LOCK();
 836         }
 837
 838         UNP_REF_LIST_UNLOCK();
 839         UNP_PCB_LOCK(unp);
 840         freeunp = unp_pcb_rele(unp);
 841         MPASS(freeunp == 0);
 842         local_unp_rights = unp_rights;
 843 teardown:
 844         unp->unp_socket->so_pcb = NULL;
 845         saved_unp_addr = unp->unp_addr;
 846         unp->unp_addr = NULL;
 847         unp->unp_socket = NULL;
 848         freeunp = unp_pcb_rele(unp);
 849         if (saved_unp_addr != NULL)
 850                 free(saved_unp_addr, M_SONAME);
 851         if (!freeunp)
 852                 UNP_PCB_UNLOCK(unp);
 853         if (vp) {
 854                 mtx_unlock(vplock);
 855                 vrele(vp);
 856         }
 857         if (local_unp_rights)
 858                 taskqueue_enqueue_timeout(taskqueue_thread, &unp_gc_task, -1);
 859 }
 860
 861 static int
 862 uipc_disconnect(struct socket *so)
 863 {
 864         struct unpcb *unp, *unp2;
 865         int freed;
 866
 867         unp = sotounpcb(so);
 868         KASSERT(unp != NULL, ("uipc_disconnect: unp == NULL"));
 869
 870         UNP_PCB_LOCK(unp);
 871         if ((unp2 = unp->unp_conn) == NULL) {
 872                 UNP_PCB_UNLOCK(unp);
 873                 return (0);
 874         }
 875         if (__predict_true(unp != unp2)) {
 876                 unp_pcb_owned_lock2(unp, unp2, freed);
 877                 if (__predict_false(freed)) {
 878                         UNP_PCB_UNLOCK(unp);
 879                         return (0);
 880                 }
 881                 unp_pcb_hold(unp2);
 882         }
 883         unp_pcb_hold(unp);
 884         unp_disconnect(unp, unp2);
 885         if (unp_pcb_rele(unp) == 0)
 886                 UNP_PCB_UNLOCK(unp);
 887         if ((unp != unp2) && unp_pcb_rele(unp2) == 0)
 888                 UNP_PCB_UNLOCK(unp2);
 889         return (0);
 890 }
 891
 892 static int
 893 uipc_listen(struct socket *so, int backlog, struct thread *td)
 894 {
 895         struct unpcb *unp;
 896         int error;
 897
 898         if (so->so_type != SOCK_STREAM && so->so_type != SOCK_SEQPACKET)
 899                 return (EOPNOTSUPP);
 900
 901         unp = sotounpcb(so);
 902         KASSERT(unp != NULL, ("uipc_listen: unp == NULL"));
 903
 904         UNP_PCB_LOCK(unp);
 905         if (unp->unp_vnode == NULL) {
 906                 /* Already connected or not bound to an address. */
 907                 error = unp->unp_conn != NULL ? EINVAL : EDESTADDRREQ;
 908                 UNP_PCB_UNLOCK(unp);
 909                 return (error);
 910         }
 911
 912         SOCK_LOCK(so);
 913         error = solisten_proto_check(so);
 914         if (error == 0) {
 915                 cru2x(td->td_ucred, &unp->unp_peercred);
 916                 solisten_proto(so, backlog);
 917         }
 918         SOCK_UNLOCK(so);
 919         UNP_PCB_UNLOCK(unp);
 920         return (error);
 921 }
 922
 923 static int
 924 uipc_peeraddr(struct socket *so, struct sockaddr **nam)
 925 {
 926         struct unpcb *unp, *unp2;
 927         const struct sockaddr *sa;
 928
 929         unp = sotounpcb(so);
 930         KASSERT(unp != NULL, ("uipc_peeraddr: unp == NULL"));
 931
 932         *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
 933         UNP_LINK_RLOCK();
 934         /*
 935          * XXX: It seems that this test always fails even when connection is
 936          * established.  So, this else clause is added as workaround to
 937          * return PF_LOCAL sockaddr.
 938          */
 939         unp2 = unp->unp_conn;
 940         if (unp2 != NULL) {
 941                 UNP_PCB_LOCK(unp2);
 942                 if (unp2->unp_addr != NULL)
 943                         sa = (struct sockaddr *) unp2->unp_addr;
 944                 else
 945                         sa = &sun_noname;
 946                 bcopy(sa, *nam, sa->sa_len);
 947                 UNP_PCB_UNLOCK(unp2);
 948         } else {
 949                 sa = &sun_noname;
 950                 bcopy(sa, *nam, sa->sa_len);
 951         }
 952         UNP_LINK_RUNLOCK();
 953         return (0);
 954 }
 955
 956 static int
 957 uipc_rcvd(struct socket *so, int flags)
 958 {
 959         struct unpcb *unp, *unp2;
 960         struct socket *so2;
 961         u_int mbcnt, sbcc;
 962
 963         unp = sotounpcb(so);
 964         KASSERT(unp != NULL, ("%s: unp == NULL", __func__));
 965         KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET,
 966             ("%s: socktype %d", __func__, so->so_type));
 967
 968         /*
 969          * Adjust backpressure on sender and wakeup any waiting to write.
 970          *
 971          * The unp lock is acquired to maintain the validity of the unp_conn
 972          * pointer; no lock on unp2 is required as unp2->unp_socket will be
 973          * static as long as we don't permit unp2 to disconnect from unp,
 974          * which is prevented by the lock on unp.  We cache values from
 975          * so_rcv to avoid holding the so_rcv lock over the entire
 976          * transaction on the remote so_snd.
 977          */
 978         SOCKBUF_LOCK(&so->so_rcv);
 979         mbcnt = so->so_rcv.sb_mbcnt;
 980         sbcc = sbavail(&so->so_rcv);
 981         SOCKBUF_UNLOCK(&so->so_rcv);
 982         /*
 983          * There is a benign race condition at this point.  If we're planning to
 984          * clear SB_STOP, but uipc_send is called on the connected socket at
 985          * this instant, it might add data to the sockbuf and set SB_STOP.  Then
 986          * we would erroneously clear SB_STOP below, even though the sockbuf is
 987          * full.  The race is benign because the only ill effect is to allow the
 988          * sockbuf to exceed its size limit, and the size limits are not
 989          * strictly guaranteed anyway.
 990          */
 991         UNP_PCB_LOCK(unp);
 992         unp2 = unp->unp_conn;
 993         if (unp2 == NULL) {
 994                 UNP_PCB_UNLOCK(unp);
 995                 return (0);
 996         }
 997         so2 = unp2->unp_socket;
 998         SOCKBUF_LOCK(&so2->so_snd);
 999         if (sbcc < so2->so_snd.sb_hiwat && mbcnt < so2->so_snd.sb_mbmax)
1000                 so2->so_snd.sb_flags &= ~SB_STOP;
1001         sowwakeup_locked(so2);
1002         UNP_PCB_UNLOCK(unp);
1003         return (0);
1004 }
1005
1006 static int
1007 connect_internal(struct socket *so, struct sockaddr *nam, struct thread *td)
1008 {
1009         int error;
1010         struct unpcb *unp;
1011
1012         unp = so->so_pcb;
1013         if (unp->unp_conn != NULL)
1014                 return (EISCONN);
1015         error = unp_connect(so, nam, td);
1016         if (error)
1017                 return (error);
1018         UNP_PCB_LOCK(unp);
1019         if (unp->unp_conn == NULL) {
1020                 UNP_PCB_UNLOCK(unp);
1021                 if (error == 0)
1022                         error = ENOTCONN;
1023         }
1024         return (error);
1025 }
1026
1027
1028 static int
1029 uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
1030     struct mbuf *control, struct thread *td)
1031 {
1032         struct unpcb *unp, *unp2;
1033         struct socket *so2;
1034         u_int mbcnt, sbcc;
1035         int freed, error;
1036
1037         unp = sotounpcb(so);
1038         KASSERT(unp != NULL, ("%s: unp == NULL", __func__));
1039         KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_DGRAM ||
1040             so->so_type == SOCK_SEQPACKET,
1041             ("%s: socktype %d", __func__, so->so_type));
1042
1043         freed = error = 0;
1044         if (flags & PRUS_OOB) {
1045                 error = EOPNOTSUPP;
1046                 goto release;
1047         }
1048         if (control != NULL && (error = unp_internalize(&control, td)))
1049                 goto release;
1050
1051         unp2 = NULL;
1052         switch (so->so_type) {
1053         case SOCK_DGRAM:
1054         {
1055                 const struct sockaddr *from;
1056
1057                 if (nam != NULL) {
1058                         /*
1059                          * We return with UNP_PCB_LOCK_HELD so we know that
1060                          * the reference is live if the pointer is valid.
1061                          */
1062                         if ((error = connect_internal(so, nam, td)))
1063                                 break;
1064                         MPASS(unp->unp_conn != NULL);
1065                         unp2 = unp->unp_conn;
1066                 } else  {
1067                         UNP_PCB_LOCK(unp);
1068
1069                         /*
1070                          * Because connect() and send() are non-atomic in a sendto()
1071                          * with a target address, it's possible that the socket will
1072                          * have disconnected before the send() can run.  In that case
1073                          * return the slightly counter-intuitive but otherwise
1074                          * correct error that the socket is not connected.
1075                          */
1076                         if ((unp2 = unp->unp_conn)  == NULL) {
1077                                 UNP_PCB_UNLOCK(unp);
1078                                 error = ENOTCONN;
1079                                 break;
1080                         }
1081                 }
1082                 if (__predict_false(unp == unp2)) {
1083                         if (unp->unp_socket == NULL) {
1084                                 error = ENOTCONN;
1085                                 break;
1086                         }
1087                         goto connect_self;
1088                 }
1089                 unp_pcb_owned_lock2(unp, unp2, freed);
1090                 if (__predict_false(freed)) {
1091                         UNP_PCB_UNLOCK(unp);
1092                         error = ENOTCONN;
1093                         break;
1094                 }
1095                 /*
1096                  * The socket referencing unp2 may have been closed
1097                  * or unp may have been disconnected if the unp lock
1098                  * was dropped to acquire unp2.
1099                  */
1100                 if (__predict_false(unp->unp_conn == NULL) ||
1101                         unp2->unp_socket == NULL) {
1102                         UNP_PCB_UNLOCK(unp);
1103                         if (unp_pcb_rele(unp2) == 0)
1104                                 UNP_PCB_UNLOCK(unp2);
1105                         error = ENOTCONN;
1106                         break;
1107                 }
1108         connect_self:
1109                 if (unp2->unp_flags & UNP_WANTCRED)
1110                         control = unp_addsockcred(td, control);
1111                 if (unp->unp_addr != NULL)
1112                         from = (struct sockaddr *)unp->unp_addr;
1113                 else
1114                         from = &sun_noname;
1115                 so2 = unp2->unp_socket;
1116                 SOCKBUF_LOCK(&so2->so_rcv);
1117                 if (sbappendaddr_locked(&so2->so_rcv, from, m,
1118                     control)) {
1119                         sorwakeup_locked(so2);
1120                         m = NULL;
1121                         control = NULL;
1122                 } else {
1123                         SOCKBUF_UNLOCK(&so2->so_rcv);
1124                         error = ENOBUFS;
1125                 }
1126                 if (nam != NULL)
1127                         unp_disconnect(unp, unp2);
1128                 if (__predict_true(unp != unp2))
1129                         UNP_PCB_UNLOCK(unp2);
1130                 UNP_PCB_UNLOCK(unp);
1131                 break;
1132         }
1133
1134         case SOCK_SEQPACKET:
1135         case SOCK_STREAM:
1136                 if ((so->so_state & SS_ISCONNECTED) == 0) {
1137                         if (nam != NULL) {
1138                                 if ((error = connect_internal(so, nam, td)))
1139                                         break;
1140                         } else  {
1141                                 error = ENOTCONN;
1142                                 break;
1143                         }
1144                 } else if ((unp2 = unp->unp_conn) == NULL) {
1145                         error = ENOTCONN;
1146                         break;
1147                 } else if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
1148                         error = EPIPE;
1149                         break;
1150                 } else {
1151                         UNP_PCB_LOCK(unp);
1152                         if ((unp2 = unp->unp_conn) == NULL) {
1153                                 UNP_PCB_UNLOCK(unp);
1154                                 error = ENOTCONN;
1155                                 break;
1156                         }
1157                 }
1158                 unp_pcb_owned_lock2(unp, unp2, freed);
1159                 UNP_PCB_UNLOCK(unp);
1160                 if (__predict_false(freed)) {
1161                         error = ENOTCONN;
1162                         break;
1163                 }
1164                 if ((so2 = unp2->unp_socket) == NULL) {
1165                         UNP_PCB_UNLOCK(unp2);
1166                         error = ENOTCONN;
1167                         break;
1168                 }
1169                 SOCKBUF_LOCK(&so2->so_rcv);
1170                 if (unp2->unp_flags & UNP_WANTCRED) {
1171                         /*
1172                          * Credentials are passed only once on SOCK_STREAM
1173                          * and SOCK_SEQPACKET.
1174                          */
1175                         unp2->unp_flags &= ~UNP_WANTCRED;
1176                         control = unp_addsockcred(td, control);
1177                 }
1178                 /*
1179                  * Send to paired receive port, and then reduce send buffer
1180                  * hiwater marks to maintain backpressure.  Wake up readers.
1181                  */
1182                 switch (so->so_type) {
1183                 case SOCK_STREAM:
1184                         if (control != NULL) {
1185                                 if (sbappendcontrol_locked(&so2->so_rcv, m,
1186                                     control))
1187                                         control = NULL;
1188                         } else
1189                                 sbappend_locked(&so2->so_rcv, m, flags);
1190                         break;
1191
1192                 case SOCK_SEQPACKET: {
1193                         const struct sockaddr *from;
1194
1195                         from = &sun_noname;
1196                         /*
1197                          * Don't check for space available in so2->so_rcv.
1198                          * Unix domain sockets only check for space in the
1199                          * sending sockbuf, and that check is performed one
1200                          * level up the stack.
1201                          */
1202                         if (sbappendaddr_nospacecheck_locked(&so2->so_rcv,
1203                                 from, m, control))
1204                                 control = NULL;
1205                         break;
1206                         }
1207                 }
1208
1209                 mbcnt = so2->so_rcv.sb_mbcnt;
1210                 sbcc = sbavail(&so2->so_rcv);
1211                 if (sbcc)
1212                         sorwakeup_locked(so2);
1213                 else
1214                         SOCKBUF_UNLOCK(&so2->so_rcv);
1215
1216                 /*
1217                  * The PCB lock on unp2 protects the SB_STOP flag.  Without it,
1218                  * it would be possible for uipc_rcvd to be called at this
1219                  * point, drain the receiving sockbuf, clear SB_STOP, and then
1220                  * we would set SB_STOP below.  That could lead to an empty
1221                  * sockbuf having SB_STOP set
1222                  */
1223                 SOCKBUF_LOCK(&so->so_snd);
1224                 if (sbcc >= so->so_snd.sb_hiwat || mbcnt >= so->so_snd.sb_mbmax)
1225                         so->so_snd.sb_flags |= SB_STOP;
1226                 SOCKBUF_UNLOCK(&so->so_snd);
1227                 UNP_PCB_UNLOCK(unp2);
1228                 m = NULL;
1229                 break;
1230         }
1231
1232         /*
1233          * PRUS_EOF is equivalent to pru_send followed by pru_shutdown.
1234          */
1235         if (flags & PRUS_EOF) {
1236                 UNP_PCB_LOCK(unp);
1237                 socantsendmore(so);
1238                 unp_shutdown(unp);
1239                 UNP_PCB_UNLOCK(unp);
1240         }
1241         if (control != NULL && error != 0)
1242                 unp_dispose_mbuf(control);
1243
1244 release:
1245         if (control != NULL)
1246                 m_freem(control);
1247         /*
1248          * In case of PRUS_NOTREADY, uipc_ready() is responsible
1249          * for freeing memory.
1250          */
1251         if (m != NULL && (flags & PRUS_NOTREADY) == 0)
1252                 m_freem(m);
1253         return (error);
1254 }
1255
1256 static int
1257 uipc_ready(struct socket *so, struct mbuf *m, int count)
1258 {
1259         struct unpcb *unp, *unp2;
1260         struct socket *so2;
1261         int error;
1262
1263         unp = sotounpcb(so);
1264
1265         UNP_PCB_LOCK(unp);
1266         if ((unp2 = unp->unp_conn) == NULL) {
1267                 UNP_PCB_UNLOCK(unp);
1268                 goto error;
1269         }
1270         if (unp != unp2) {
1271                 if (UNP_PCB_TRYLOCK(unp2) == 0) {
1272                         unp_pcb_hold(unp2);
1273                         UNP_PCB_UNLOCK(unp);
1274                         UNP_PCB_LOCK(unp2);
1275                         if (unp_pcb_rele(unp2))
1276                                 goto error;
1277                 } else
1278                         UNP_PCB_UNLOCK(unp);
1279         }
1280         so2 = unp2->unp_socket;
1281
1282         SOCKBUF_LOCK(&so2->so_rcv);
1283         if ((error = sbready(&so2->so_rcv, m, count)) == 0)
1284                 sorwakeup_locked(so2);
1285         else
1286                 SOCKBUF_UNLOCK(&so2->so_rcv);
1287
1288         UNP_PCB_UNLOCK(unp2);
1289
1290         return (error);
1291  error:
1292         for (int i = 0; i < count; i++)
1293                 m = m_free(m);
1294         return (ECONNRESET);
1295 }
1296
1297 static int
1298 uipc_sense(struct socket *so, struct stat *sb)
1299 {
1300         struct unpcb *unp;
1301
1302         unp = sotounpcb(so);
1303         KASSERT(unp != NULL, ("uipc_sense: unp == NULL"));
1304
1305         sb->st_blksize = so->so_snd.sb_hiwat;
1306         UNP_PCB_LOCK(unp);
1307         sb->st_dev = NODEV;
1308         if (unp->unp_ino == 0)
1309                 unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino;
1310         sb->st_ino = unp->unp_ino;
1311         UNP_PCB_UNLOCK(unp);
1312         return (0);
1313 }
1314
1315 static int
1316 uipc_shutdown(struct socket *so)
1317 {
1318         struct unpcb *unp;
1319
1320         unp = sotounpcb(so);
1321         KASSERT(unp != NULL, ("uipc_shutdown: unp == NULL"));
1322
1323         UNP_PCB_LOCK(unp);
1324         socantsendmore(so);
1325         unp_shutdown(unp);
1326         UNP_PCB_UNLOCK(unp);
1327         return (0);
1328 }
1329
1330 static int
1331 uipc_sockaddr(struct socket *so, struct sockaddr **nam)
1332 {
1333         struct unpcb *unp;
1334         const struct sockaddr *sa;
1335
1336         unp = sotounpcb(so);
1337         KASSERT(unp != NULL, ("uipc_sockaddr: unp == NULL"));
1338
1339         *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
1340         UNP_PCB_LOCK(unp);
1341         if (unp->unp_addr != NULL)
1342                 sa = (struct sockaddr *) unp->unp_addr;
1343         else
1344                 sa = &sun_noname;
1345         bcopy(sa, *nam, sa->sa_len);
1346         UNP_PCB_UNLOCK(unp);
1347         return (0);
1348 }
1349
1350 static struct pr_usrreqs uipc_usrreqs_dgram = {
1351         .pru_abort =            uipc_abort,
1352         .pru_accept =           uipc_accept,
1353         .pru_attach =           uipc_attach,
1354         .pru_bind =             uipc_bind,
1355         .pru_bindat =           uipc_bindat,
1356         .pru_connect =          uipc_connect,
1357         .pru_connectat =        uipc_connectat,
1358         .pru_connect2 =         uipc_connect2,
1359         .pru_detach =           uipc_detach,
1360         .pru_disconnect =       uipc_disconnect,
1361         .pru_listen =           uipc_listen,
1362         .pru_peeraddr =         uipc_peeraddr,
1363         .pru_rcvd =             uipc_rcvd,
1364         .pru_send =             uipc_send,
1365         .pru_sense =            uipc_sense,
1366         .pru_shutdown =         uipc_shutdown,
1367         .pru_sockaddr =         uipc_sockaddr,
1368         .pru_soreceive =        soreceive_dgram,
1369         .pru_close =            uipc_close,
1370 };
1371
1372 static struct pr_usrreqs uipc_usrreqs_seqpacket = {
1373         .pru_abort =            uipc_abort,
1374         .pru_accept =           uipc_accept,
1375         .pru_attach =           uipc_attach,
1376         .pru_bind =             uipc_bind,
1377         .pru_bindat =           uipc_bindat,
1378         .pru_connect =          uipc_connect,
1379         .pru_connectat =        uipc_connectat,
1380         .pru_connect2 =         uipc_connect2,
1381         .pru_detach =           uipc_detach,
1382         .pru_disconnect =       uipc_disconnect,
1383         .pru_listen =           uipc_listen,
1384         .pru_peeraddr =         uipc_peeraddr,
1385         .pru_rcvd =             uipc_rcvd,
1386         .pru_send =             uipc_send,
1387         .pru_sense =            uipc_sense,
1388         .pru_shutdown =         uipc_shutdown,
1389         .pru_sockaddr =         uipc_sockaddr,
1390         .pru_soreceive =        soreceive_generic,      /* XXX: or...? */
1391         .pru_close =            uipc_close,
1392 };
1393
1394 static struct pr_usrreqs uipc_usrreqs_stream = {
1395         .pru_abort =            uipc_abort,
1396         .pru_accept =           uipc_accept,
1397         .pru_attach =           uipc_attach,
1398         .pru_bind =             uipc_bind,
1399         .pru_bindat =           uipc_bindat,
1400         .pru_connect =          uipc_connect,
1401         .pru_connectat =        uipc_connectat,
1402         .pru_connect2 =         uipc_connect2,
1403         .pru_detach =           uipc_detach,
1404         .pru_disconnect =       uipc_disconnect,
1405         .pru_listen =           uipc_listen,
1406         .pru_peeraddr =         uipc_peeraddr,
1407         .pru_rcvd =             uipc_rcvd,
1408         .pru_send =             uipc_send,
1409         .pru_ready =            uipc_ready,
1410         .pru_sense =            uipc_sense,
1411         .pru_shutdown =         uipc_shutdown,
1412         .pru_sockaddr =         uipc_sockaddr,
1413         .pru_soreceive =        soreceive_generic,
1414         .pru_close =            uipc_close,
1415 };
1416
1417 static int
1418 uipc_ctloutput(struct socket *so, struct sockopt *sopt)
1419 {
1420         struct unpcb *unp;
1421         struct xucred xu;
1422         int error, optval;
1423
1424         if (sopt->sopt_level != 0)
1425                 return (EINVAL);
1426
1427         unp = sotounpcb(so);
1428         KASSERT(unp != NULL, ("uipc_ctloutput: unp == NULL"));
1429         error = 0;
1430         switch (sopt->sopt_dir) {
1431         case SOPT_GET:
1432                 switch (sopt->sopt_name) {
1433                 case LOCAL_PEERCRED:
1434                         UNP_PCB_LOCK(unp);
1435                         if (unp->unp_flags & UNP_HAVEPC)
1436                                 xu = unp->unp_peercred;
1437                         else {
1438                                 if (so->so_type == SOCK_STREAM)
1439                                         error = ENOTCONN;
1440                                 else
1441                                         error = EINVAL;
1442                         }
1443                         UNP_PCB_UNLOCK(unp);
1444                         if (error == 0)
1445                                 error = sooptcopyout(sopt, &xu, sizeof(xu));
1446                         break;
1447
1448                 case LOCAL_CREDS:
1449                         /* Unlocked read. */
1450                         optval = unp->unp_flags & UNP_WANTCRED ? 1 : 0;
1451                         error = sooptcopyout(sopt, &optval, sizeof(optval));
1452                         break;
1453
1454                 case LOCAL_CONNWAIT:
1455                         /* Unlocked read. */
1456                         optval = unp->unp_flags & UNP_CONNWAIT ? 1 : 0;
1457                         error = sooptcopyout(sopt, &optval, sizeof(optval));
1458                         break;
1459
1460                 default:
1461                         error = EOPNOTSUPP;
1462                         break;
1463                 }
1464                 break;
1465
1466         case SOPT_SET:
1467                 switch (sopt->sopt_name) {
1468                 case LOCAL_CREDS:
1469                 case LOCAL_CONNWAIT:
1470                         error = sooptcopyin(sopt, &optval, sizeof(optval),
1471                                             sizeof(optval));
1472                         if (error)
1473                                 break;
1474
1475 #define OPTSET(bit) do {                                                \
1476         UNP_PCB_LOCK(unp);                                              \
1477         if (optval)                                                     \
1478                 unp->unp_flags |= bit;                                  \
1479         else                                                            \
1480                 unp->unp_flags &= ~bit;                                 \
1481         UNP_PCB_UNLOCK(unp);                                            \
1482 } while (0)
1483
1484                         switch (sopt->sopt_name) {
1485                         case LOCAL_CREDS:
1486                                 OPTSET(UNP_WANTCRED);
1487                                 break;
1488
1489                         case LOCAL_CONNWAIT:
1490                                 OPTSET(UNP_CONNWAIT);
1491                                 break;
1492
1493                         default:
1494                                 break;
1495                         }
1496                         break;
1497 #undef  OPTSET
1498                 default:
1499                         error = ENOPROTOOPT;
1500                         break;
1501                 }
1502                 break;
1503
1504         default:
1505                 error = EOPNOTSUPP;
1506                 break;
1507         }
1508         return (error);
1509 }
1510
1511 static int
1512 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
1513 {
1514
1515         return (unp_connectat(AT_FDCWD, so, nam, td));
1516 }
1517
1518 static int
1519 unp_connectat(int fd, struct socket *so, struct sockaddr *nam,
1520     struct thread *td)
1521 {
1522         struct sockaddr_un *soun = (struct sockaddr_un *)nam;
1523         struct vnode *vp;
1524         struct socket *so2;
1525         struct unpcb *unp, *unp2, *unp3;
1526         struct nameidata nd;
1527         char buf[SOCK_MAXADDRLEN];
1528         struct sockaddr *sa;
1529         cap_rights_t rights;
1530         int error, len, freed;
1531         struct mtx *vplock;
1532
1533         if (nam->sa_family != AF_UNIX)
1534                 return (EAFNOSUPPORT);
1535         if (nam->sa_len > sizeof(struct sockaddr_un))
1536                 return (EINVAL);
1537         len = nam->sa_len - offsetof(struct sockaddr_un, sun_path);
1538         if (len <= 0)
1539                 return (EINVAL);
1540         bcopy(soun->sun_path, buf, len);
1541         buf[len] = 0;
1542
1543         unp = sotounpcb(so);
1544         UNP_PCB_LOCK(unp);
1545         if (unp->unp_flags & UNP_CONNECTING) {
1546                 UNP_PCB_UNLOCK(unp);
1547                 return (EALREADY);
1548         }
1549         unp->unp_flags |= UNP_CONNECTING;
1550         UNP_PCB_UNLOCK(unp);
1551
1552         sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
1553         NDINIT_ATRIGHTS(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF,
1554             UIO_SYSSPACE, buf, fd, cap_rights_init(&rights, CAP_CONNECTAT), td);
1555         error = namei(&nd);
1556         if (error)
1557                 vp = NULL;
1558         else
1559                 vp = nd.ni_vp;
1560         ASSERT_VOP_LOCKED(vp, "unp_connect");
1561         NDFREE(&nd, NDF_ONLY_PNBUF);
1562         if (error)
1563                 goto bad;
1564
1565         if (vp->v_type != VSOCK) {
1566                 error = ENOTSOCK;
1567                 goto bad;
1568         }
1569 #ifdef MAC
1570         error = mac_vnode_check_open(td->td_ucred, vp, VWRITE | VREAD);
1571         if (error)
1572                 goto bad;
1573 #endif
1574         error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td);
1575         if (error)
1576                 goto bad;
1577
1578         unp = sotounpcb(so);
1579         KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
1580
1581         vplock = mtx_pool_find(mtxpool_sleep, vp);
1582         mtx_lock(vplock);
1583         VOP_UNP_CONNECT(vp, &unp2);
1584         if (unp2 == NULL) {
1585                 error = ECONNREFUSED;
1586                 goto bad2;
1587         }
1588         so2 = unp2->unp_socket;
1589         if (so->so_type != so2->so_type) {
1590                 error = EPROTOTYPE;
1591                 goto bad2;
1592         }
1593         if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
1594                 if (so2->so_options & SO_ACCEPTCONN) {
1595                         CURVNET_SET(so2->so_vnet);
1596                         so2 = sonewconn(so2, 0);
1597                         CURVNET_RESTORE();
1598                 } else
1599                         so2 = NULL;
1600                 if (so2 == NULL) {
1601                         error = ECONNREFUSED;
1602                         goto bad2;
1603                 }
1604                 unp3 = sotounpcb(so2);
1605                 unp_pcb_lock2(unp2, unp3);
1606                 if (unp2->unp_addr != NULL) {
1607                         bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len);
1608                         unp3->unp_addr = (struct sockaddr_un *) sa;
1609                         sa = NULL;
1610                 }
1611
1612                 unp_copy_peercred(td, unp3, unp, unp2);
1613
1614                 UNP_PCB_UNLOCK(unp2);
1615                 unp2 = unp3;
1616                 unp_pcb_owned_lock2(unp2, unp, freed);
1617                 if (__predict_false(freed)) {
1618                         UNP_PCB_UNLOCK(unp2);
1619                         error = ECONNREFUSED;
1620                         goto bad2;
1621                 }
1622 #ifdef MAC
1623                 mac_socketpeer_set_from_socket(so, so2);
1624                 mac_socketpeer_set_from_socket(so2, so);
1625 #endif
1626         } else {
1627                 if (unp == unp2)
1628                         UNP_PCB_LOCK(unp);
1629                 else
1630                         unp_pcb_lock2(unp, unp2);
1631         }
1632         KASSERT(unp2 != NULL && so2 != NULL && unp2->unp_socket == so2 &&
1633             sotounpcb(so2) == unp2,
1634             ("%s: unp2 %p so2 %p", __func__, unp2, so2));
1635         error = unp_connect2(so, so2, PRU_CONNECT);
1636         if (unp != unp2)
1637                 UNP_PCB_UNLOCK(unp2);
1638         UNP_PCB_UNLOCK(unp);
1639 bad2:
1640         mtx_unlock(vplock);
1641 bad:
1642         if (vp != NULL) {
1643                 vput(vp);
1644         }
1645         free(sa, M_SONAME);
1646         UNP_PCB_LOCK(unp);
1647         unp->unp_flags &= ~UNP_CONNECTING;
1648         UNP_PCB_UNLOCK(unp);
1649         return (error);
1650 }
1651
1652 /*
1653  * Set socket peer credentials at connection time.
1654  *
1655  * The client's PCB credentials are copied from its process structure.  The
1656  * server's PCB credentials are copied from the socket on which it called
1657  * listen(2).  uipc_listen cached that process's credentials at the time.
1658  */
1659 void
1660 unp_copy_peercred(struct thread *td, struct unpcb *client_unp,
1661     struct unpcb *server_unp, struct unpcb *listen_unp)
1662 {
1663         cru2x(td->td_ucred, &client_unp->unp_peercred);
1664         client_unp->unp_flags |= UNP_HAVEPC;
1665
1666         memcpy(&server_unp->unp_peercred, &listen_unp->unp_peercred,
1667             sizeof(server_unp->unp_peercred));
1668         server_unp->unp_flags |= UNP_HAVEPC;
1669         if (listen_unp->unp_flags & UNP_WANTCRED)
1670                 client_unp->unp_flags |= UNP_WANTCRED;
1671 }
1672
1673 static int
1674 unp_connect2(struct socket *so, struct socket *so2, int req)
1675 {
1676         struct unpcb *unp;
1677         struct unpcb *unp2;
1678
1679         unp = sotounpcb(so);
1680         KASSERT(unp != NULL, ("unp_connect2: unp == NULL"));
1681         unp2 = sotounpcb(so2);
1682         KASSERT(unp2 != NULL, ("unp_connect2: unp2 == NULL"));
1683
1684         UNP_PCB_LOCK_ASSERT(unp);
1685         UNP_PCB_LOCK_ASSERT(unp2);
1686
1687         if (so2->so_type != so->so_type)
1688                 return (EPROTOTYPE);
1689         unp2->unp_flags &= ~UNP_NASCENT;
1690         unp->unp_conn = unp2;
1691         unp_pcb_hold(unp2);
1692         unp_pcb_hold(unp);
1693         switch (so->so_type) {
1694         case SOCK_DGRAM:
1695                 UNP_REF_LIST_LOCK();
1696                 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink);
1697                 UNP_REF_LIST_UNLOCK();
1698                 soisconnected(so);
1699                 break;
1700
1701         case SOCK_STREAM:
1702         case SOCK_SEQPACKET:
1703                 unp2->unp_conn = unp;
1704                 if (req == PRU_CONNECT &&
1705                     ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT))
1706                         soisconnecting(so);
1707                 else
1708                         soisconnected(so);
1709                 soisconnected(so2);
1710                 break;
1711
1712         default:
1713                 panic("unp_connect2");
1714         }
1715         return (0);
1716 }
1717
1718 static void
1719 unp_disconnect(struct unpcb *unp, struct unpcb *unp2)
1720 {
1721         struct socket *so, *so2;
1722         int freed __unused;
1723
1724         KASSERT(unp2 != NULL, ("unp_disconnect: unp2 == NULL"));
1725
1726         UNP_PCB_LOCK_ASSERT(unp);
1727         UNP_PCB_LOCK_ASSERT(unp2);
1728
1729         if (unp->unp_conn == NULL && unp2->unp_conn == NULL)
1730                 return;
1731
1732         MPASS(unp->unp_conn == unp2);
1733         unp->unp_conn = NULL;
1734         so = unp->unp_socket;
1735         so2 = unp2->unp_socket;
1736         switch (unp->unp_socket->so_type) {
1737         case SOCK_DGRAM:
1738                 UNP_REF_LIST_LOCK();
1739                 LIST_REMOVE(unp, unp_reflink);
1740                 UNP_REF_LIST_UNLOCK();
1741                 if (so) {
1742                         SOCK_LOCK(so);
1743                         so->so_state &= ~SS_ISCONNECTED;
1744                         SOCK_UNLOCK(so);
1745                 }
1746                 break;
1747
1748         case SOCK_STREAM:
1749         case SOCK_SEQPACKET:
1750                 if (so)
1751                         soisdisconnected(so);
1752                 MPASS(unp2->unp_conn == unp);
1753                 unp2->unp_conn = NULL;
1754                 if (so2)
1755                         soisdisconnected(so2);
1756                 break;
1757         }
1758         freed = unp_pcb_rele(unp);
1759         MPASS(freed == 0);
1760         freed = unp_pcb_rele(unp2);
1761         MPASS(freed == 0);
1762 }
1763
1764 /*
1765  * unp_pcblist() walks the global list of struct unpcb's to generate a
1766  * pointer list, bumping the refcount on each unpcb.  It then copies them out
1767  * sequentially, validating the generation number on each to see if it has
1768  * been detached.  All of this is necessary because copyout() may sleep on
1769  * disk I/O.
1770  */
1771 static int
1772 unp_pcblist(SYSCTL_HANDLER_ARGS)
1773 {
1774         struct unpcb *unp, **unp_list;
1775         unp_gen_t gencnt;
1776         struct xunpgen *xug;
1777         struct unp_head *head;
1778         struct xunpcb *xu;
1779         u_int i;
1780         int error, freeunp, n;
1781
1782         switch ((intptr_t)arg1) {
1783         case SOCK_STREAM:
1784                 head = &unp_shead;
1785                 break;
1786
1787         case SOCK_DGRAM:
1788                 head = &unp_dhead;
1789                 break;
1790
1791         case SOCK_SEQPACKET:
1792                 head = &unp_sphead;
1793                 break;
1794
1795         default:
1796                 panic("unp_pcblist: arg1 %d", (int)(intptr_t)arg1);
1797         }
1798
1799         /*
1800          * The process of preparing the PCB list is too time-consuming and
1801          * resource-intensive to repeat twice on every request.
1802          */
1803         if (req->oldptr == NULL) {
1804                 n = unp_count;
1805                 req->oldidx = 2 * (sizeof *xug)
1806                         + (n + n/8) * sizeof(struct xunpcb);
1807                 return (0);
1808         }
1809
1810         if (req->newptr != NULL)
1811                 return (EPERM);
1812
1813         /*
1814          * OK, now we're committed to doing something.
1815          */
1816         xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK);
1817         UNP_LINK_RLOCK();
1818         gencnt = unp_gencnt;
1819         n = unp_count;
1820         UNP_LINK_RUNLOCK();
1821
1822         xug->xug_len = sizeof *xug;
1823         xug->xug_count = n;
1824         xug->xug_gen = gencnt;
1825         xug->xug_sogen = so_gencnt;
1826         error = SYSCTL_OUT(req, xug, sizeof *xug);
1827         if (error) {
1828                 free(xug, M_TEMP);
1829                 return (error);
1830         }
1831
1832         unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK);
1833
1834         UNP_LINK_RLOCK();
1835         for (unp = LIST_FIRST(head), i = 0; unp && i < n;
1836              unp = LIST_NEXT(unp, unp_link)) {
1837                 UNP_PCB_LOCK(unp);
1838                 if (unp->unp_gencnt <= gencnt) {
1839                         if (cr_cansee(req->td->td_ucred,
1840                             unp->unp_socket->so_cred)) {
1841                                 UNP_PCB_UNLOCK(unp);
1842                                 continue;
1843                         }
1844                         unp_list[i++] = unp;
1845                         unp_pcb_hold(unp);
1846                 }
1847                 UNP_PCB_UNLOCK(unp);
1848         }
1849         UNP_LINK_RUNLOCK();
1850         n = i;                  /* In case we lost some during malloc. */
1851
1852         error = 0;
1853         xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK | M_ZERO);
1854         for (i = 0; i < n; i++) {
1855                 unp = unp_list[i];
1856                 UNP_PCB_LOCK(unp);
1857                 freeunp = unp_pcb_rele(unp);
1858
1859                 if (freeunp == 0 && unp->unp_gencnt <= gencnt) {
1860                         xu->xu_len = sizeof *xu;
1861                         xu->xu_unpp = (uintptr_t)unp;
1862                         /*
1863                          * XXX - need more locking here to protect against
1864                          * connect/disconnect races for SMP.
1865                          */
1866                         if (unp->unp_addr != NULL)
1867                                 bcopy(unp->unp_addr, &xu->xu_addr,
1868                                       unp->unp_addr->sun_len);
1869                         else
1870                                 bzero(&xu->xu_addr, sizeof(xu->xu_addr));
1871                         if (unp->unp_conn != NULL &&
1872                             unp->unp_conn->unp_addr != NULL)
1873                                 bcopy(unp->unp_conn->unp_addr,
1874                                       &xu->xu_caddr,
1875                                       unp->unp_conn->unp_addr->sun_len);
1876                         else
1877                                 bzero(&xu->xu_caddr, sizeof(xu->xu_caddr));
1878                         xu->unp_vnode = (uintptr_t)unp->unp_vnode;
1879                         xu->unp_conn = (uintptr_t)unp->unp_conn;
1880                         xu->xu_firstref = (uintptr_t)LIST_FIRST(&unp->unp_refs);
1881                         xu->xu_nextref = (uintptr_t)LIST_NEXT(unp, unp_reflink);
1882                         xu->unp_gencnt = unp->unp_gencnt;
1883                         sotoxsocket(unp->unp_socket, &xu->xu_socket);
1884                         UNP_PCB_UNLOCK(unp);
1885                         error = SYSCTL_OUT(req, xu, sizeof *xu);
1886                 } else  if (freeunp == 0)
1887                         UNP_PCB_UNLOCK(unp);
1888         }
1889         free(xu, M_TEMP);
1890         if (!error) {
1891                 /*
1892                  * Give the user an updated idea of our state.  If the
1893                  * generation differs from what we told her before, she knows
1894                  * that something happened while we were processing this
1895                  * request, and it might be necessary to retry.
1896                  */
1897                 xug->xug_gen = unp_gencnt;
1898                 xug->xug_sogen = so_gencnt;
1899                 xug->xug_count = unp_count;
1900                 error = SYSCTL_OUT(req, xug, sizeof *xug);
1901         }
1902         free(unp_list, M_TEMP);
1903         free(xug, M_TEMP);
1904         return (error);
1905 }
1906
1907 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLTYPE_OPAQUE | CTLFLAG_RD,
1908     (void *)(intptr_t)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb",
1909     "List of active local datagram sockets");
1910 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLTYPE_OPAQUE | CTLFLAG_RD,
1911     (void *)(intptr_t)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb",
1912     "List of active local stream sockets");
1913 SYSCTL_PROC(_net_local_seqpacket, OID_AUTO, pcblist,
1914     CTLTYPE_OPAQUE | CTLFLAG_RD,
1915     (void *)(intptr_t)SOCK_SEQPACKET, 0, unp_pcblist, "S,xunpcb",
1916     "List of active local seqpacket sockets");
1917
1918 static void
1919 unp_shutdown(struct unpcb *unp)
1920 {
1921         struct unpcb *unp2;
1922         struct socket *so;
1923
1924         UNP_PCB_LOCK_ASSERT(unp);
1925
1926         unp2 = unp->unp_conn;
1927         if ((unp->unp_socket->so_type == SOCK_STREAM ||
1928             (unp->unp_socket->so_type == SOCK_SEQPACKET)) && unp2 != NULL) {
1929                 so = unp2->unp_socket;
1930                 if (so != NULL)
1931                         socantrcvmore(so);
1932         }
1933 }
1934
1935 static void
1936 unp_drop(struct unpcb *unp)
1937 {
1938         struct socket *so = unp->unp_socket;
1939         struct unpcb *unp2;
1940         int freed;
1941
1942         /*
1943          * Regardless of whether the socket's peer dropped the connection
1944          * with this socket by aborting or disconnecting, POSIX requires
1945          * that ECONNRESET is returned.
1946          */
1947         /* acquire a reference so that unp isn't freed from underneath us */
1948
1949         UNP_PCB_LOCK(unp);
1950         if (so)
1951                 so->so_error = ECONNRESET;
1952         unp2 = unp->unp_conn;
1953         if (unp2 == unp) {
1954                 unp_disconnect(unp, unp2);
1955         } else if (unp2 != NULL) {
1956                 unp_pcb_hold(unp2);
1957                 unp_pcb_owned_lock2(unp, unp2, freed);
1958                 unp_disconnect(unp, unp2);
1959                 if (unp_pcb_rele(unp2) == 0)
1960                         UNP_PCB_UNLOCK(unp2);
1961         }
1962         if (unp_pcb_rele(unp) == 0)
1963                 UNP_PCB_UNLOCK(unp);
1964 }
1965
1966 static void
1967 unp_freerights(struct filedescent **fdep, int fdcount)
1968 {
1969         struct file *fp;
1970         int i;
1971
1972         KASSERT(fdcount > 0, ("%s: fdcount %d", __func__, fdcount));
1973
1974         for (i = 0; i < fdcount; i++) {
1975                 fp = fdep[i]->fde_file;
1976                 filecaps_free(&fdep[i]->fde_caps);
1977                 unp_discard(fp);
1978         }
1979         free(fdep[0], M_FILECAPS);
1980 }
1981
1982 static int
1983 unp_externalize(struct mbuf *control, struct mbuf **controlp, int flags)
1984 {
1985         struct thread *td = curthread;          /* XXX */
1986         struct cmsghdr *cm = mtod(control, struct cmsghdr *);
1987         int i;
1988         int *fdp;
1989         struct filedesc *fdesc = td->td_proc->p_fd;
1990         struct filedescent **fdep;
1991         void *data;
1992         socklen_t clen = control->m_len, datalen;
1993         int error, newfds;
1994         u_int newlen;
1995
1996         UNP_LINK_UNLOCK_ASSERT();
1997
1998         error = 0;
1999         if (controlp != NULL) /* controlp == NULL => free control messages */
2000                 *controlp = NULL;
2001         while (cm != NULL) {
2002                 if (sizeof(*cm) > clen || cm->cmsg_len > clen) {
2003                         error = EINVAL;
2004                         break;
2005                 }
2006                 data = CMSG_DATA(cm);
2007                 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
2008                 if (cm->cmsg_level == SOL_SOCKET
2009                     && cm->cmsg_type == SCM_RIGHTS) {
2010                         newfds = datalen / sizeof(*fdep);
2011                         if (newfds == 0)
2012                                 goto next;
2013                         fdep = data;
2014
2015                         /* If we're not outputting the descriptors free them. */
2016                         if (error || controlp == NULL) {
2017                                 unp_freerights(fdep, newfds);
2018                                 goto next;
2019                         }
2020                         FILEDESC_XLOCK(fdesc);
2021
2022                         /*
2023                          * Now change each pointer to an fd in the global
2024                          * table to an integer that is the index to the local
2025                          * fd table entry that we set up to point to the
2026                          * global one we are transferring.
2027                          */
2028                         newlen = newfds * sizeof(int);
2029                         *controlp = sbcreatecontrol(NULL, newlen,
2030                             SCM_RIGHTS, SOL_SOCKET);
2031                         if (*controlp == NULL) {
2032                                 FILEDESC_XUNLOCK(fdesc);
2033                                 error = E2BIG;
2034                                 unp_freerights(fdep, newfds);
2035                                 goto next;
2036                         }
2037
2038                         fdp = (int *)
2039                             CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2040                         if (fdallocn(td, 0, fdp, newfds) != 0) {
2041                                 FILEDESC_XUNLOCK(fdesc);
2042                                 error = EMSGSIZE;
2043                                 unp_freerights(fdep, newfds);
2044                                 m_freem(*controlp);
2045                                 *controlp = NULL;
2046                                 goto next;
2047                         }
2048                         for (i = 0; i < newfds; i++, fdp++) {
2049                                 _finstall(fdesc, fdep[i]->fde_file, *fdp,
2050                                     (flags & MSG_CMSG_CLOEXEC) != 0 ? UF_EXCLOSE : 0,
2051                                     &fdep[i]->fde_caps);
2052                                 unp_externalize_fp(fdep[i]->fde_file);
2053                         }
2054                         FILEDESC_XUNLOCK(fdesc);
2055                         free(fdep[0], M_FILECAPS);
2056                 } else {
2057                         /* We can just copy anything else across. */
2058                         if (error || controlp == NULL)
2059                                 goto next;
2060                         *controlp = sbcreatecontrol(NULL, datalen,
2061                             cm->cmsg_type, cm->cmsg_level);
2062                         if (*controlp == NULL) {
2063                                 error = ENOBUFS;
2064                                 goto next;
2065                         }
2066                         bcopy(data,
2067                             CMSG_DATA(mtod(*controlp, struct cmsghdr *)),
2068                             datalen);
2069                 }
2070                 controlp = &(*controlp)->m_next;
2071
2072 next:
2073                 if (CMSG_SPACE(datalen) < clen) {
2074                         clen -= CMSG_SPACE(datalen);
2075                         cm = (struct cmsghdr *)
2076                             ((caddr_t)cm + CMSG_SPACE(datalen));
2077                 } else {
2078                         clen = 0;
2079                         cm = NULL;
2080                 }
2081         }
2082
2083         m_freem(control);
2084         return (error);
2085 }
2086
2087 static void
2088 unp_zone_change(void *tag)
2089 {
2090
2091         uma_zone_set_max(unp_zone, maxsockets);
2092 }
2093
2094 static void
2095 unp_init(void)
2096 {
2097
2098 #ifdef VIMAGE
2099         if (!IS_DEFAULT_VNET(curvnet))
2100                 return;
2101 #endif
2102         unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL,
2103             NULL, NULL, UMA_ALIGN_CACHE, 0);
2104         if (unp_zone == NULL)
2105                 panic("unp_init");
2106         uma_zone_set_max(unp_zone, maxsockets);
2107         uma_zone_set_warning(unp_zone, "kern.ipc.maxsockets limit reached");
2108         EVENTHANDLER_REGISTER(maxsockets_change, unp_zone_change,
2109             NULL, EVENTHANDLER_PRI_ANY);
2110         LIST_INIT(&unp_dhead);
2111         LIST_INIT(&unp_shead);
2112         LIST_INIT(&unp_sphead);
2113         SLIST_INIT(&unp_defers);
2114         TIMEOUT_TASK_INIT(taskqueue_thread, &unp_gc_task, 0, unp_gc, NULL);
2115         TASK_INIT(&unp_defer_task, 0, unp_process_defers, NULL);
2116         UNP_LINK_LOCK_INIT();
2117         UNP_DEFERRED_LOCK_INIT();
2118 }
2119
2120 static int
2121 unp_internalize(struct mbuf **controlp, struct thread *td)
2122 {
2123         struct mbuf *control = *controlp;
2124         struct proc *p = td->td_proc;
2125         struct filedesc *fdesc = p->p_fd;
2126         struct bintime *bt;
2127         struct cmsghdr *cm = mtod(control, struct cmsghdr *);
2128         struct cmsgcred *cmcred;
2129         struct filedescent *fde, **fdep, *fdev;
2130         struct file *fp;
2131         struct timeval *tv;
2132         struct timespec *ts;
2133         int i, *fdp;
2134         void *data;
2135         socklen_t clen = control->m_len, datalen;
2136         int error, oldfds;
2137         u_int newlen;
2138
2139         UNP_LINK_UNLOCK_ASSERT();
2140
2141         error = 0;
2142         *controlp = NULL;
2143         while (cm != NULL) {
2144                 if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET
2145                     || cm->cmsg_len > clen || cm->cmsg_len < sizeof(*cm)) {
2146                         error = EINVAL;
2147                         goto out;
2148                 }
2149                 data = CMSG_DATA(cm);
2150                 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
2151
2152                 switch (cm->cmsg_type) {
2153                 /*
2154                  * Fill in credential information.
2155                  */
2156                 case SCM_CREDS:
2157                         *controlp = sbcreatecontrol(NULL, sizeof(*cmcred),
2158                             SCM_CREDS, SOL_SOCKET);
2159                         if (*controlp == NULL) {
2160                                 error = ENOBUFS;
2161                                 goto out;
2162                         }
2163                         cmcred = (struct cmsgcred *)
2164                             CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2165                         cmcred->cmcred_pid = p->p_pid;
2166                         cmcred->cmcred_uid = td->td_ucred->cr_ruid;
2167                         cmcred->cmcred_gid = td->td_ucred->cr_rgid;
2168                         cmcred->cmcred_euid = td->td_ucred->cr_uid;
2169                         cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups,
2170                             CMGROUP_MAX);
2171                         for (i = 0; i < cmcred->cmcred_ngroups; i++)
2172                                 cmcred->cmcred_groups[i] =
2173                                     td->td_ucred->cr_groups[i];
2174                         break;
2175
2176                 case SCM_RIGHTS:
2177                         oldfds = datalen / sizeof (int);
2178                         if (oldfds == 0)
2179                                 break;
2180                         /*
2181                          * Check that all the FDs passed in refer to legal
2182                          * files.  If not, reject the entire operation.
2183                          */
2184                         fdp = data;
2185                         FILEDESC_SLOCK(fdesc);
2186                         for (i = 0; i < oldfds; i++, fdp++) {
2187                                 fp = fget_locked(fdesc, *fdp);
2188                                 if (fp == NULL) {
2189                                         FILEDESC_SUNLOCK(fdesc);
2190                                         error = EBADF;
2191                                         goto out;
2192                                 }
2193                                 if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) {
2194                                         FILEDESC_SUNLOCK(fdesc);
2195                                         error = EOPNOTSUPP;
2196                                         goto out;
2197                                 }
2198
2199                         }
2200
2201                         /*
2202                          * Now replace the integer FDs with pointers to the
2203                          * file structure and capability rights.
2204                          */
2205                         newlen = oldfds * sizeof(fdep[0]);
2206                         *controlp = sbcreatecontrol(NULL, newlen,
2207                             SCM_RIGHTS, SOL_SOCKET);
2208                         if (*controlp == NULL) {
2209                                 FILEDESC_SUNLOCK(fdesc);
2210                                 error = E2BIG;
2211                                 goto out;
2212                         }
2213                         fdp = data;
2214                         fdep = (struct filedescent **)
2215                             CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2216                         fdev = malloc(sizeof(*fdev) * oldfds, M_FILECAPS,
2217                             M_WAITOK);
2218                         for (i = 0; i < oldfds; i++, fdev++, fdp++) {
2219                                 fde = &fdesc->fd_ofiles[*fdp];
2220                                 fdep[i] = fdev;
2221                                 fdep[i]->fde_file = fde->fde_file;
2222                                 filecaps_copy(&fde->fde_caps,
2223                                     &fdep[i]->fde_caps, true);
2224                                 unp_internalize_fp(fdep[i]->fde_file);
2225                         }
2226                         FILEDESC_SUNLOCK(fdesc);
2227                         break;
2228
2229                 case SCM_TIMESTAMP:
2230                         *controlp = sbcreatecontrol(NULL, sizeof(*tv),
2231                             SCM_TIMESTAMP, SOL_SOCKET);
2232                         if (*controlp == NULL) {
2233                                 error = ENOBUFS;
2234                                 goto out;
2235                         }
2236                         tv = (struct timeval *)
2237                             CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2238                         microtime(tv);
2239                         break;
2240
2241                 case SCM_BINTIME:
2242                         *controlp = sbcreatecontrol(NULL, sizeof(*bt),
2243                             SCM_BINTIME, SOL_SOCKET);
2244                         if (*controlp == NULL) {
2245                                 error = ENOBUFS;
2246                                 goto out;
2247                         }
2248                         bt = (struct bintime *)
2249                             CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2250                         bintime(bt);
2251                         break;
2252
2253                 case SCM_REALTIME:
2254                         *controlp = sbcreatecontrol(NULL, sizeof(*ts),
2255                             SCM_REALTIME, SOL_SOCKET);
2256                         if (*controlp == NULL) {
2257                                 error = ENOBUFS;
2258                                 goto out;
2259                         }
2260                         ts = (struct timespec *)
2261                             CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2262                         nanotime(ts);
2263                         break;
2264
2265                 case SCM_MONOTONIC:
2266                         *controlp = sbcreatecontrol(NULL, sizeof(*ts),
2267                             SCM_MONOTONIC, SOL_SOCKET);
2268                         if (*controlp == NULL) {
2269                                 error = ENOBUFS;
2270                                 goto out;
2271                         }
2272                         ts = (struct timespec *)
2273                             CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2274                         nanouptime(ts);
2275                         break;
2276
2277                 default:
2278                         error = EINVAL;
2279                         goto out;
2280                 }
2281
2282                 controlp = &(*controlp)->m_next;
2283                 if (CMSG_SPACE(datalen) < clen) {
2284                         clen -= CMSG_SPACE(datalen);
2285                         cm = (struct cmsghdr *)
2286                             ((caddr_t)cm + CMSG_SPACE(datalen));
2287                 } else {
2288                         clen = 0;
2289                         cm = NULL;
2290                 }
2291         }
2292
2293 out:
2294         m_freem(control);
2295         return (error);
2296 }
2297
2298 static struct mbuf *
2299 unp_addsockcred(struct thread *td, struct mbuf *control)
2300 {
2301         struct mbuf *m, *n, *n_prev;
2302         struct sockcred *sc;
2303         const struct cmsghdr *cm;
2304         int ngroups;
2305         int i;
2306
2307         ngroups = MIN(td->td_ucred->cr_ngroups, CMGROUP_MAX);
2308         m = sbcreatecontrol(NULL, SOCKCREDSIZE(ngroups), SCM_CREDS, SOL_SOCKET);
2309         if (m == NULL)
2310                 return (control);
2311
2312         sc = (struct sockcred *) CMSG_DATA(mtod(m, struct cmsghdr *));
2313         sc->sc_uid = td->td_ucred->cr_ruid;
2314         sc->sc_euid = td->td_ucred->cr_uid;
2315         sc->sc_gid = td->td_ucred->cr_rgid;
2316         sc->sc_egid = td->td_ucred->cr_gid;
2317         sc->sc_ngroups = ngroups;
2318         for (i = 0; i < sc->sc_ngroups; i++)
2319                 sc->sc_groups[i] = td->td_ucred->cr_groups[i];
2320
2321         /*
2322          * Unlink SCM_CREDS control messages (struct cmsgcred), since just
2323          * created SCM_CREDS control message (struct sockcred) has another
2324          * format.
2325          */
2326         if (control != NULL)
2327                 for (n = control, n_prev = NULL; n != NULL;) {
2328                         cm = mtod(n, struct cmsghdr *);
2329                         if (cm->cmsg_level == SOL_SOCKET &&
2330                             cm->cmsg_type == SCM_CREDS) {
2331                                 if (n_prev == NULL)
2332                                         control = n->m_next;
2333                                 else
2334                                         n_prev->m_next = n->m_next;
2335                                 n = m_free(n);
2336                         } else {
2337                                 n_prev = n;
2338                                 n = n->m_next;
2339                         }
2340                 }
2341
2342         /* Prepend it to the head. */
2343         m->m_next = control;
2344         return (m);
2345 }
2346
2347 static struct unpcb *
2348 fptounp(struct file *fp)
2349 {
2350         struct socket *so;
2351
2352         if (fp->f_type != DTYPE_SOCKET)
2353                 return (NULL);
2354         if ((so = fp->f_data) == NULL)
2355                 return (NULL);
2356         if (so->so_proto->pr_domain != &localdomain)
2357                 return (NULL);
2358         return sotounpcb(so);
2359 }
2360
2361 static void
2362 unp_discard(struct file *fp)
2363 {
2364         struct unp_defer *dr;
2365
2366         if (unp_externalize_fp(fp)) {
2367                 dr = malloc(sizeof(*dr), M_TEMP, M_WAITOK);
2368                 dr->ud_fp = fp;
2369                 UNP_DEFERRED_LOCK();
2370                 SLIST_INSERT_HEAD(&unp_defers, dr, ud_link);
2371                 UNP_DEFERRED_UNLOCK();
2372                 atomic_add_int(&unp_defers_count, 1);
2373                 taskqueue_enqueue(taskqueue_thread, &unp_defer_task);
2374         } else
2375                 (void) closef(fp, (struct thread *)NULL);
2376 }
2377
2378 static void
2379 unp_process_defers(void *arg __unused, int pending)
2380 {
2381         struct unp_defer *dr;
2382         SLIST_HEAD(, unp_defer) drl;
2383         int count;
2384
2385         SLIST_INIT(&drl);
2386         for (;;) {
2387                 UNP_DEFERRED_LOCK();
2388                 if (SLIST_FIRST(&unp_defers) == NULL) {
2389                         UNP_DEFERRED_UNLOCK();
2390                         break;
2391                 }
2392                 SLIST_SWAP(&unp_defers, &drl, unp_defer);
2393                 UNP_DEFERRED_UNLOCK();
2394                 count = 0;
2395                 while ((dr = SLIST_FIRST(&drl)) != NULL) {
2396                         SLIST_REMOVE_HEAD(&drl, ud_link);
2397                         closef(dr->ud_fp, NULL);
2398                         free(dr, M_TEMP);
2399                         count++;
2400                 }
2401                 atomic_add_int(&unp_defers_count, -count);
2402         }
2403 }
2404
2405 static void
2406 unp_internalize_fp(struct file *fp)
2407 {
2408         struct unpcb *unp;
2409
2410         UNP_LINK_WLOCK();
2411         if ((unp = fptounp(fp)) != NULL) {
2412                 unp->unp_file = fp;
2413                 unp->unp_msgcount++;
2414         }
2415         fhold(fp);
2416         unp_rights++;
2417         UNP_LINK_WUNLOCK();
2418 }
2419
2420 static int
2421 unp_externalize_fp(struct file *fp)
2422 {
2423         struct unpcb *unp;
2424         int ret;
2425
2426         UNP_LINK_WLOCK();
2427         if ((unp = fptounp(fp)) != NULL) {
2428                 unp->unp_msgcount--;
2429                 ret = 1;
2430         } else
2431                 ret = 0;
2432         unp_rights--;
2433         UNP_LINK_WUNLOCK();
2434         return (ret);
2435 }
2436
2437 /*
2438  * unp_defer indicates whether additional work has been defered for a future
2439  * pass through unp_gc().  It is thread local and does not require explicit
2440  * synchronization.
2441  */
2442 static int      unp_marked;
2443 static int      unp_unreachable;
2444
2445 static void
2446 unp_accessable(struct filedescent **fdep, int fdcount)
2447 {
2448         struct unpcb *unp;
2449         struct file *fp;
2450         int i;
2451
2452         for (i = 0; i < fdcount; i++) {
2453                 fp = fdep[i]->fde_file;
2454                 if ((unp = fptounp(fp)) == NULL)
2455                         continue;
2456                 if (unp->unp_gcflag & UNPGC_REF)
2457                         continue;
2458                 unp->unp_gcflag &= ~UNPGC_DEAD;
2459                 unp->unp_gcflag |= UNPGC_REF;
2460                 unp_marked++;
2461         }
2462 }
2463
2464 static void
2465 unp_gc_process(struct unpcb *unp)
2466 {
2467         struct socket *so, *soa;
2468         struct file *fp;
2469
2470         /* Already processed. */
2471         if (unp->unp_gcflag & UNPGC_SCANNED)
2472                 return;
2473         fp = unp->unp_file;
2474
2475         /*
2476          * Check for a socket potentially in a cycle.  It must be in a
2477          * queue as indicated by msgcount, and this must equal the file
2478          * reference count.  Note that when msgcount is 0 the file is NULL.
2479          */
2480         if ((unp->unp_gcflag & UNPGC_REF) == 0 && fp &&
2481             unp->unp_msgcount != 0 && fp->f_count == unp->unp_msgcount) {
2482                 unp->unp_gcflag |= UNPGC_DEAD;
2483                 unp_unreachable++;
2484                 return;
2485         }
2486
2487         so = unp->unp_socket;
2488         SOCK_LOCK(so);
2489         if (SOLISTENING(so)) {
2490                 /*
2491                  * Mark all sockets in our accept queue.
2492                  */
2493                 TAILQ_FOREACH(soa, &so->sol_comp, so_list) {
2494                         if (sotounpcb(soa)->unp_gcflag & UNPGC_IGNORE_RIGHTS)
2495                                 continue;
2496                         SOCKBUF_LOCK(&soa->so_rcv);
2497                         unp_scan(soa->so_rcv.sb_mb, unp_accessable);
2498                         SOCKBUF_UNLOCK(&soa->so_rcv);
2499                 }
2500         } else {
2501                 /*
2502                  * Mark all sockets we reference with RIGHTS.
2503                  */
2504                 if ((unp->unp_gcflag & UNPGC_IGNORE_RIGHTS) == 0) {
2505                         SOCKBUF_LOCK(&so->so_rcv);
2506                         unp_scan(so->so_rcv.sb_mb, unp_accessable);
2507                         SOCKBUF_UNLOCK(&so->so_rcv);
2508                 }
2509         }
2510         SOCK_UNLOCK(so);
2511         unp->unp_gcflag |= UNPGC_SCANNED;
2512 }
2513
2514 static int unp_recycled;
2515 SYSCTL_INT(_net_local, OID_AUTO, recycled, CTLFLAG_RD, &unp_recycled, 0,
2516     "Number of unreachable sockets claimed by the garbage collector.");
2517
2518 static int unp_taskcount;
2519 SYSCTL_INT(_net_local, OID_AUTO, taskcount, CTLFLAG_RD, &unp_taskcount, 0,
2520     "Number of times the garbage collector has run.");
2521
2522 static void
2523 unp_gc(__unused void *arg, int pending)
2524 {
2525         struct unp_head *heads[] = { &unp_dhead, &unp_shead, &unp_sphead,
2526                                     NULL };
2527         struct unp_head **head;
2528         struct file *f, **unref;
2529         struct unpcb *unp;
2530         int i, total;
2531
2532         unp_taskcount++;
2533         UNP_LINK_RLOCK();
2534         /*
2535          * First clear all gc flags from previous runs, apart from
2536          * UNPGC_IGNORE_RIGHTS.
2537          */
2538         for (head = heads; *head != NULL; head++)
2539                 LIST_FOREACH(unp, *head, unp_link)
2540                         unp->unp_gcflag =
2541                             (unp->unp_gcflag & UNPGC_IGNORE_RIGHTS);
2542
2543         /*
2544          * Scan marking all reachable sockets with UNPGC_REF.  Once a socket
2545          * is reachable all of the sockets it references are reachable.
2546          * Stop the scan once we do a complete loop without discovering
2547          * a new reachable socket.
2548          */
2549         do {
2550                 unp_unreachable = 0;
2551                 unp_marked = 0;
2552                 for (head = heads; *head != NULL; head++)
2553                         LIST_FOREACH(unp, *head, unp_link)
2554                                 unp_gc_process(unp);
2555         } while (unp_marked);
2556         UNP_LINK_RUNLOCK();
2557         if (unp_unreachable == 0)
2558                 return;
2559
2560         /*
2561          * Allocate space for a local list of dead unpcbs.
2562          */
2563         unref = malloc(unp_unreachable * sizeof(struct file *),
2564             M_TEMP, M_WAITOK);
2565
2566         /*
2567          * Iterate looking for sockets which have been specifically marked
2568          * as as unreachable and store them locally.
2569          */
2570         UNP_LINK_RLOCK();
2571         for (total = 0, head = heads; *head != NULL; head++)
2572                 LIST_FOREACH(unp, *head, unp_link)
2573                         if ((unp->unp_gcflag & UNPGC_DEAD) != 0) {
2574                                 f = unp->unp_file;
2575                                 if (unp->unp_msgcount == 0 || f == NULL ||
2576                                     f->f_count != unp->unp_msgcount)
2577                                         continue;
2578                                 unref[total++] = f;
2579                                 fhold(f);
2580                                 KASSERT(total <= unp_unreachable,
2581                                     ("unp_gc: incorrect unreachable count."));
2582                         }
2583         UNP_LINK_RUNLOCK();
2584
2585         /*
2586          * Now flush all sockets, free'ing rights.  This will free the
2587          * struct files associated with these sockets but leave each socket
2588          * with one remaining ref.
2589          */
2590         for (i = 0; i < total; i++) {
2591                 struct socket *so;
2592
2593                 so = unref[i]->f_data;
2594                 CURVNET_SET(so->so_vnet);
2595                 sorflush(so);
2596                 CURVNET_RESTORE();
2597         }
2598
2599         /*
2600          * And finally release the sockets so they can be reclaimed.
2601          */
2602         for (i = 0; i < total; i++)
2603                 fdrop(unref[i], NULL);
2604         unp_recycled += total;
2605         free(unref, M_TEMP);
2606 }
2607
2608 static void
2609 unp_dispose_mbuf(struct mbuf *m)
2610 {
2611
2612         if (m)
2613                 unp_scan(m, unp_freerights);
2614 }
2615
2616 /*
2617  * Synchronize against unp_gc, which can trip over data as we are freeing it.
2618  */
2619 static void
2620 unp_dispose(struct socket *so)
2621 {
2622         struct unpcb *unp;
2623
2624         unp = sotounpcb(so);
2625         UNP_LINK_WLOCK();
2626         unp->unp_gcflag |= UNPGC_IGNORE_RIGHTS;
2627         UNP_LINK_WUNLOCK();
2628         if (!SOLISTENING(so))
2629                 unp_dispose_mbuf(so->so_rcv.sb_mb);
2630 }
2631
2632 static void
2633 unp_scan(struct mbuf *m0, void (*op)(struct filedescent **, int))
2634 {
2635         struct mbuf *m;
2636         struct cmsghdr *cm;
2637         void *data;
2638         socklen_t clen, datalen;
2639
2640         while (m0 != NULL) {
2641                 for (m = m0; m; m = m->m_next) {
2642                         if (m->m_type != MT_CONTROL)
2643                                 continue;
2644
2645                         cm = mtod(m, struct cmsghdr *);
2646                         clen = m->m_len;
2647
2648                         while (cm != NULL) {
2649                                 if (sizeof(*cm) > clen || cm->cmsg_len > clen)
2650                                         break;
2651
2652                                 data = CMSG_DATA(cm);
2653                                 datalen = (caddr_t)cm + cm->cmsg_len
2654                                     - (caddr_t)data;
2655
2656                                 if (cm->cmsg_level == SOL_SOCKET &&
2657                                     cm->cmsg_type == SCM_RIGHTS) {
2658                                         (*op)(data, datalen /
2659                                             sizeof(struct filedescent *));
2660                                 }
2661
2662                                 if (CMSG_SPACE(datalen) < clen) {
2663                                         clen -= CMSG_SPACE(datalen);
2664                                         cm = (struct cmsghdr *)
2665                                             ((caddr_t)cm + CMSG_SPACE(datalen));
2666                                 } else {
2667                                         clen = 0;
2668                                         cm = NULL;
2669                                 }
2670                         }
2671                 }
2672                 m0 = m0->m_nextpkt;
2673         }
2674 }
2675
2676 /*
2677  * A helper function called by VFS before socket-type vnode reclamation.
2678  * For an active vnode it clears unp_vnode pointer and decrements unp_vnode
2679  * use count.
2680  */
2681 void
2682 vfs_unp_reclaim(struct vnode *vp)
2683 {
2684         struct unpcb *unp;
2685         int active;
2686         struct mtx *vplock;
2687
2688         ASSERT_VOP_ELOCKED(vp, "vfs_unp_reclaim");
2689         KASSERT(vp->v_type == VSOCK,
2690             ("vfs_unp_reclaim: vp->v_type != VSOCK"));
2691
2692         active = 0;
2693         vplock = mtx_pool_find(mtxpool_sleep, vp);
2694         mtx_lock(vplock);
2695         VOP_UNP_CONNECT(vp, &unp);
2696         if (unp == NULL)
2697                 goto done;
2698         UNP_PCB_LOCK(unp);
2699         if (unp->unp_vnode == vp) {
2700                 VOP_UNP_DETACH(vp);
2701                 unp->unp_vnode = NULL;
2702                 active = 1;
2703         }
2704         UNP_PCB_UNLOCK(unp);
2705  done:
2706         mtx_unlock(vplock);
2707         if (active)
2708                 vunref(vp);
2709 }
2710
2711 #ifdef DDB
2712 static void
2713 db_print_indent(int indent)
2714 {
2715         int i;
2716
2717         for (i = 0; i < indent; i++)
2718                 db_printf(" ");
2719 }
2720
2721 static void
2722 db_print_unpflags(int unp_flags)
2723 {
2724         int comma;
2725
2726         comma = 0;
2727         if (unp_flags & UNP_HAVEPC) {
2728                 db_printf("%sUNP_HAVEPC", comma ? ", " : "");
2729                 comma = 1;
2730         }
2731         if (unp_flags & UNP_WANTCRED) {
2732                 db_printf("%sUNP_WANTCRED", comma ? ", " : "");
2733                 comma = 1;
2734         }
2735         if (unp_flags & UNP_CONNWAIT) {
2736                 db_printf("%sUNP_CONNWAIT", comma ? ", " : "");
2737                 comma = 1;
2738         }
2739         if (unp_flags & UNP_CONNECTING) {
2740                 db_printf("%sUNP_CONNECTING", comma ? ", " : "");
2741                 comma = 1;
2742         }
2743         if (unp_flags & UNP_BINDING) {
2744                 db_printf("%sUNP_BINDING", comma ? ", " : "");
2745                 comma = 1;
2746         }
2747 }
2748
2749 static void
2750 db_print_xucred(int indent, struct xucred *xu)
2751 {
2752         int comma, i;
2753
2754         db_print_indent(indent);
2755         db_printf("cr_version: %u   cr_uid: %u   cr_ngroups: %d\n",
2756             xu->cr_version, xu->cr_uid, xu->cr_ngroups);
2757         db_print_indent(indent);
2758         db_printf("cr_groups: ");
2759         comma = 0;
2760         for (i = 0; i < xu->cr_ngroups; i++) {
2761                 db_printf("%s%u", comma ? ", " : "", xu->cr_groups[i]);
2762                 comma = 1;
2763         }
2764         db_printf("\n");
2765 }
2766
2767 static void
2768 db_print_unprefs(int indent, struct unp_head *uh)
2769 {
2770         struct unpcb *unp;
2771         int counter;
2772
2773         counter = 0;
2774         LIST_FOREACH(unp, uh, unp_reflink) {
2775                 if (counter % 4 == 0)
2776                         db_print_indent(indent);
2777                 db_printf("%p  ", unp);
2778                 if (counter % 4 == 3)
2779                         db_printf("\n");
2780                 counter++;
2781         }
2782         if (counter != 0 && counter % 4 != 0)
2783                 db_printf("\n");
2784 }
2785
2786 DB_SHOW_COMMAND(unpcb, db_show_unpcb)
2787 {
2788         struct unpcb *unp;
2789
2790         if (!have_addr) {
2791                 db_printf("usage: show unpcb <addr>\n");
2792                 return;
2793         }
2794         unp = (struct unpcb *)addr;
2795
2796         db_printf("unp_socket: %p   unp_vnode: %p\n", unp->unp_socket,
2797             unp->unp_vnode);
2798
2799         db_printf("unp_ino: %ju   unp_conn: %p\n", (uintmax_t)unp->unp_ino,
2800             unp->unp_conn);
2801
2802         db_printf("unp_refs:\n");
2803         db_print_unprefs(2, &unp->unp_refs);
2804
2805         /* XXXRW: Would be nice to print the full address, if any. */
2806         db_printf("unp_addr: %p\n", unp->unp_addr);
2807
2808         db_printf("unp_gencnt: %llu\n",
2809             (unsigned long long)unp->unp_gencnt);
2810
2811         db_printf("unp_flags: %x (", unp->unp_flags);
2812         db_print_unpflags(unp->unp_flags);
2813         db_printf(")\n");
2814
2815         db_printf("unp_peercred:\n");
2816         db_print_xucred(2, &unp->unp_peercred);
2817
2818         db_printf("unp_refcount: %u\n", unp->unp_refcount);
2819 }
2820 #endif