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freebsd/sys/kern/uipc_usrreq.c
Gleb Smirnoff 5716d902ae Revert "unix: new implementation of unix/stream & unix/seqpacket" 
The regressions in aio(4) and kernel RPC aren't a 5 minute problem.

This reverts commit d80a97def9.
This reverts commit d1cbb17a87.
This reverts commit fb8a8333b4.
2024-04-09 13:15:47 -07:00

3572 lines
92 KiB
C
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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California. All Rights Reserved.
* Copyright (c) 2004-2009 Robert N. M. Watson All Rights Reserved.
* Copyright (c) 2018 Matthew Macy
* Copyright (c) 2022 Gleb Smirnoff <glebius@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* UNIX Domain (Local) Sockets
*
* This is an implementation of UNIX (local) domain sockets. Each socket has
* an associated struct unpcb (UNIX protocol control block). Stream sockets
* may be connected to 0 or 1 other socket. Datagram sockets may be
* connected to 0, 1, or many other sockets. Sockets may be created and
* connected in pairs (socketpair(2)), or bound/connected to using the file
* system name space. For most purposes, only the receive socket buffer is
* used, as sending on one socket delivers directly to the receive socket
* buffer of a second socket.
*
* The implementation is substantially complicated by the fact that
* "ancillary data", such as file descriptors or credentials, may be passed
* across UNIX domain sockets. The potential for passing UNIX domain sockets
* over other UNIX domain sockets requires the implementation of a simple
* garbage collector to find and tear down cycles of disconnected sockets.
*
* TODO:
* RDM
* rethink name space problems
* need a proper out-of-band
*/
#include <sys/cdefs.h>
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/capsicum.h>
#include <sys/domain.h>
#include <sys/eventhandler.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/queue.h>
#include <sys/resourcevar.h>
#include <sys/rwlock.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/signalvar.h>
#include <sys/stat.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/taskqueue.h>
#include <sys/un.h>
#include <sys/unpcb.h>
#include <sys/vnode.h>
#include <net/vnet.h>
#ifdef DDB
#include <ddb/ddb.h>
#endif
#include <security/mac/mac_framework.h>
#include <vm/uma.h>
MALLOC_DECLARE(M_FILECAPS);
static struct domain localdomain;
static uma_zone_t unp_zone;
static unp_gen_t unp_gencnt; /* (l) */
static u_int unp_count; /* (l) Count of local sockets. */
static ino_t unp_ino; /* Prototype for fake inode numbers. */
static int unp_rights; /* (g) File descriptors in flight. */
static struct unp_head unp_shead; /* (l) List of stream sockets. */
static struct unp_head unp_dhead; /* (l) List of datagram sockets. */
static struct unp_head unp_sphead; /* (l) List of seqpacket sockets. */
struct unp_defer {
SLIST_ENTRY(unp_defer) ud_link;
struct file *ud_fp;
};
static SLIST_HEAD(, unp_defer) unp_defers;
static int unp_defers_count;
static const struct sockaddr sun_noname = {
.sa_len = sizeof(sun_noname),
.sa_family = AF_LOCAL,
};
/*
* Garbage collection of cyclic file descriptor/socket references occurs
* asynchronously in a taskqueue context in order to avoid recursion and
* reentrance in the UNIX domain socket, file descriptor, and socket layer
* code. See unp_gc() for a full description.
*/
static struct timeout_task unp_gc_task;
/*
* The close of unix domain sockets attached as SCM_RIGHTS is
* postponed to the taskqueue, to avoid arbitrary recursion depth.
* The attached sockets might have another sockets attached.
*/
static struct task unp_defer_task;
/*
* Both send and receive buffers are allocated PIPSIZ bytes of buffering for
* stream sockets, although the total for sender and receiver is actually
* only PIPSIZ.
*
* Datagram sockets really use the sendspace as the maximum datagram size,
* and don't really want to reserve the sendspace. Their recvspace should be
* large enough for at least one max-size datagram plus address.
*/
#ifndef PIPSIZ
#define PIPSIZ 8192
#endif
static u_long unpst_sendspace = PIPSIZ;
static u_long unpst_recvspace = PIPSIZ;
static u_long unpdg_maxdgram = 8*1024; /* support 8KB syslog msgs */
static u_long unpdg_recvspace = 16*1024;
static u_long unpsp_sendspace = PIPSIZ; /* really max datagram size */
static u_long unpsp_recvspace = PIPSIZ;
static SYSCTL_NODE(_net, PF_LOCAL, local, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"Local domain");
static SYSCTL_NODE(_net_local, SOCK_STREAM, stream,
CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"SOCK_STREAM");
static SYSCTL_NODE(_net_local, SOCK_DGRAM, dgram,
CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"SOCK_DGRAM");
static SYSCTL_NODE(_net_local, SOCK_SEQPACKET, seqpacket,
CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"SOCK_SEQPACKET");
SYSCTL_ULONG(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW,
&unpst_sendspace, 0, "Default stream send space.");
SYSCTL_ULONG(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW,
&unpst_recvspace, 0, "Default stream receive space.");
SYSCTL_ULONG(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW,
&unpdg_maxdgram, 0, "Maximum datagram size.");
SYSCTL_ULONG(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW,
&unpdg_recvspace, 0, "Default datagram receive space.");
SYSCTL_ULONG(_net_local_seqpacket, OID_AUTO, maxseqpacket, CTLFLAG_RW,
&unpsp_sendspace, 0, "Default seqpacket send space.");
SYSCTL_ULONG(_net_local_seqpacket, OID_AUTO, recvspace, CTLFLAG_RW,
&unpsp_recvspace, 0, "Default seqpacket receive space.");
SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0,
"File descriptors in flight.");
SYSCTL_INT(_net_local, OID_AUTO, deferred, CTLFLAG_RD,
&unp_defers_count, 0,
"File descriptors deferred to taskqueue for close.");
/*
* Locking and synchronization:
*
* Several types of locks exist in the local domain socket implementation:
* - a global linkage lock
* - a global connection list lock
* - the mtxpool lock
* - per-unpcb mutexes
*
* The linkage lock protects the global socket lists, the generation number
* counter and garbage collector state.
*
* The connection list lock protects the list of referring sockets in a datagram
* socket PCB. This lock is also overloaded to protect a global list of
* sockets whose buffers contain socket references in the form of SCM_RIGHTS
* messages. To avoid recursion, such references are released by a dedicated
* thread.
*
* The mtxpool lock protects the vnode from being modified while referenced.
* Lock ordering rules require that it be acquired before any PCB locks.
*
* The unpcb lock (unp_mtx) protects the most commonly referenced fields in the
* unpcb. This includes the unp_conn field, which either links two connected
* PCBs together (for connected socket types) or points at the destination
* socket (for connectionless socket types). The operations of creating or
* destroying a connection therefore involve locking multiple PCBs. To avoid
* lock order reversals, in some cases this involves dropping a PCB lock and
* using a reference counter to maintain liveness.
*
* UNIX domain sockets each have an unpcb hung off of their so_pcb pointer,
* allocated in pr_attach() and freed in pr_detach(). The validity of that
* pointer is an invariant, so no lock is required to dereference the so_pcb
* pointer if a valid socket reference is held by the caller. In practice,
* this is always true during operations performed on a socket. Each unpcb
* has a back-pointer to its socket, unp_socket, which will be stable under
* the same circumstances.
*
* This pointer may only be safely dereferenced as long as a valid reference
* to the unpcb is held. Typically, this reference will be from the socket,
* or from another unpcb when the referring unpcb's lock is held (in order
* that the reference not be invalidated during use). For example, to follow
* unp->unp_conn->unp_socket, you need to hold a lock on unp_conn to guarantee
* that detach is not run clearing unp_socket.
*
* Blocking with UNIX domain sockets is a tricky issue: unlike most network
* protocols, bind() is a non-atomic operation, and connect() requires
* potential sleeping in the protocol, due to potentially waiting on local or
* distributed file systems. We try to separate "lookup" operations, which
* may sleep, and the IPC operations themselves, which typically can occur
* with relative atomicity as locks can be held over the entire operation.
*
* Another tricky issue is simultaneous multi-threaded or multi-process
* access to a single UNIX domain socket. These are handled by the flags
* UNP_CONNECTING and UNP_BINDING, which prevent concurrent connecting or
* binding, both of which involve dropping UNIX domain socket locks in order
* to perform namei() and other file system operations.
*/
static struct rwlock unp_link_rwlock;
static struct mtx unp_defers_lock;
#define UNP_LINK_LOCK_INIT() rw_init(&unp_link_rwlock, \
"unp_link_rwlock")
#define UNP_LINK_LOCK_ASSERT() rw_assert(&unp_link_rwlock, \
RA_LOCKED)
#define UNP_LINK_UNLOCK_ASSERT() rw_assert(&unp_link_rwlock, \
RA_UNLOCKED)
#define UNP_LINK_RLOCK() rw_rlock(&unp_link_rwlock)
#define UNP_LINK_RUNLOCK() rw_runlock(&unp_link_rwlock)
#define UNP_LINK_WLOCK() rw_wlock(&unp_link_rwlock)
#define UNP_LINK_WUNLOCK() rw_wunlock(&unp_link_rwlock)
#define UNP_LINK_WLOCK_ASSERT() rw_assert(&unp_link_rwlock, \
RA_WLOCKED)
#define UNP_LINK_WOWNED() rw_wowned(&unp_link_rwlock)
#define UNP_DEFERRED_LOCK_INIT() mtx_init(&unp_defers_lock, \
"unp_defer", NULL, MTX_DEF)
#define UNP_DEFERRED_LOCK() mtx_lock(&unp_defers_lock)
#define UNP_DEFERRED_UNLOCK() mtx_unlock(&unp_defers_lock)
#define UNP_REF_LIST_LOCK() UNP_DEFERRED_LOCK();
#define UNP_REF_LIST_UNLOCK() UNP_DEFERRED_UNLOCK();
#define UNP_PCB_LOCK_INIT(unp) mtx_init(&(unp)->unp_mtx, \
"unp", "unp", \
MTX_DUPOK|MTX_DEF)
#define UNP_PCB_LOCK_DESTROY(unp) mtx_destroy(&(unp)->unp_mtx)
#define UNP_PCB_LOCKPTR(unp) (&(unp)->unp_mtx)
#define UNP_PCB_LOCK(unp) mtx_lock(&(unp)->unp_mtx)
#define UNP_PCB_TRYLOCK(unp) mtx_trylock(&(unp)->unp_mtx)
#define UNP_PCB_UNLOCK(unp) mtx_unlock(&(unp)->unp_mtx)
#define UNP_PCB_OWNED(unp) mtx_owned(&(unp)->unp_mtx)
#define UNP_PCB_LOCK_ASSERT(unp) mtx_assert(&(unp)->unp_mtx, MA_OWNED)
#define UNP_PCB_UNLOCK_ASSERT(unp) mtx_assert(&(unp)->unp_mtx, MA_NOTOWNED)
static int uipc_connect2(struct socket *, struct socket *);
static int uipc_ctloutput(struct socket *, struct sockopt *);
static int unp_connect(struct socket *, struct sockaddr *,
struct thread *);
static int unp_connectat(int, struct socket *, struct sockaddr *,
struct thread *, bool);
static void unp_connect2(struct socket *so, struct socket *so2);
static void unp_disconnect(struct unpcb *unp, struct unpcb *unp2);
static void unp_dispose(struct socket *so);
static void unp_shutdown(struct unpcb *);
static void unp_drop(struct unpcb *);
static void unp_gc(__unused void *, int);
static void unp_scan(struct mbuf *, void (*)(struct filedescent **, int));
static void unp_discard(struct file *);
static void unp_freerights(struct filedescent **, int);
static int unp_internalize(struct mbuf **, struct thread *,
struct mbuf **, u_int *, u_int *);
static void unp_internalize_fp(struct file *);
static int unp_externalize(struct mbuf *, struct mbuf **, int);
static int unp_externalize_fp(struct file *);
static struct mbuf *unp_addsockcred(struct thread *, struct mbuf *,
int, struct mbuf **, u_int *, u_int *);
static void unp_process_defers(void * __unused, int);
static void
unp_pcb_hold(struct unpcb *unp)
{
u_int old __unused;
old = refcount_acquire(&unp->unp_refcount);
KASSERT(old > 0, ("%s: unpcb %p has no references", __func__, unp));
}
static __result_use_check bool
unp_pcb_rele(struct unpcb *unp)
{
bool ret;
UNP_PCB_LOCK_ASSERT(unp);
if ((ret = refcount_release(&unp->unp_refcount))) {
UNP_PCB_UNLOCK(unp);
UNP_PCB_LOCK_DESTROY(unp);
uma_zfree(unp_zone, unp);
}
return (ret);
}
static void
unp_pcb_rele_notlast(struct unpcb *unp)
{
bool ret __unused;
ret = refcount_release(&unp->unp_refcount);
KASSERT(!ret, ("%s: unpcb %p has no references", __func__, unp));
}
static void
unp_pcb_lock_pair(struct unpcb *unp, struct unpcb *unp2)
{
UNP_PCB_UNLOCK_ASSERT(unp);
UNP_PCB_UNLOCK_ASSERT(unp2);
if (unp == unp2) {
UNP_PCB_LOCK(unp);
} else if ((uintptr_t)unp2 > (uintptr_t)unp) {
UNP_PCB_LOCK(unp);
UNP_PCB_LOCK(unp2);
} else {
UNP_PCB_LOCK(unp2);
UNP_PCB_LOCK(unp);
}
}
static void
unp_pcb_unlock_pair(struct unpcb *unp, struct unpcb *unp2)
{
UNP_PCB_UNLOCK(unp);
if (unp != unp2)
UNP_PCB_UNLOCK(unp2);
}
/*
* Try to lock the connected peer of an already locked socket. In some cases
* this requires that we unlock the current socket. The pairbusy counter is
* used to block concurrent connection attempts while the lock is dropped. The
* caller must be careful to revalidate PCB state.
*/
static struct unpcb *
unp_pcb_lock_peer(struct unpcb *unp)
{
struct unpcb *unp2;
UNP_PCB_LOCK_ASSERT(unp);
unp2 = unp->unp_conn;
if (unp2 == NULL)
return (NULL);
if (__predict_false(unp == unp2))
return (unp);
UNP_PCB_UNLOCK_ASSERT(unp2);
if (__predict_true(UNP_PCB_TRYLOCK(unp2)))
return (unp2);
if ((uintptr_t)unp2 > (uintptr_t)unp) {
UNP_PCB_LOCK(unp2);
return (unp2);
}
unp->unp_pairbusy++;
unp_pcb_hold(unp2);
UNP_PCB_UNLOCK(unp);
UNP_PCB_LOCK(unp2);
UNP_PCB_LOCK(unp);
KASSERT(unp->unp_conn == unp2 || unp->unp_conn == NULL,
("%s: socket %p was reconnected", __func__, unp));
if (--unp->unp_pairbusy == 0 && (unp->unp_flags & UNP_WAITING) != 0) {
unp->unp_flags &= ~UNP_WAITING;
wakeup(unp);
}
if (unp_pcb_rele(unp2)) {
/* unp2 is unlocked. */
return (NULL);
}
if (unp->unp_conn == NULL) {
UNP_PCB_UNLOCK(unp2);
return (NULL);
}
return (unp2);
}
static void
uipc_abort(struct socket *so)
{
struct unpcb *unp, *unp2;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_abort: unp == NULL"));
UNP_PCB_UNLOCK_ASSERT(unp);
UNP_PCB_LOCK(unp);
unp2 = unp->unp_conn;
if (unp2 != NULL) {
unp_pcb_hold(unp2);
UNP_PCB_UNLOCK(unp);
unp_drop(unp2);
} else
UNP_PCB_UNLOCK(unp);
}
static int
uipc_attach(struct socket *so, int proto, struct thread *td)
{
u_long sendspace, recvspace;
struct unpcb *unp;
int error;
bool locked;
KASSERT(so->so_pcb == NULL, ("uipc_attach: so_pcb != NULL"));
if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
switch (so->so_type) {
case SOCK_STREAM:
sendspace = unpst_sendspace;
recvspace = unpst_recvspace;
break;
case SOCK_DGRAM:
STAILQ_INIT(&so->so_rcv.uxdg_mb);
STAILQ_INIT(&so->so_snd.uxdg_mb);
TAILQ_INIT(&so->so_rcv.uxdg_conns);
/*
* Since send buffer is either bypassed or is a part
* of one-to-many receive buffer, we assign both space
* limits to unpdg_recvspace.
*/
sendspace = recvspace = unpdg_recvspace;
break;
case SOCK_SEQPACKET:
sendspace = unpsp_sendspace;
recvspace = unpsp_recvspace;
break;
default:
panic("uipc_attach");
}
error = soreserve(so, sendspace, recvspace);
if (error)
return (error);
}
unp = uma_zalloc(unp_zone, M_NOWAIT | M_ZERO);
if (unp == NULL)
return (ENOBUFS);
LIST_INIT(&unp->unp_refs);
UNP_PCB_LOCK_INIT(unp);
unp->unp_socket = so;
so->so_pcb = unp;
refcount_init(&unp->unp_refcount, 1);
if ((locked = UNP_LINK_WOWNED()) == false)
UNP_LINK_WLOCK();
unp->unp_gencnt = ++unp_gencnt;
unp->unp_ino = ++unp_ino;
unp_count++;
switch (so->so_type) {
case SOCK_STREAM:
LIST_INSERT_HEAD(&unp_shead, unp, unp_link);
break;
case SOCK_DGRAM:
LIST_INSERT_HEAD(&unp_dhead, unp, unp_link);
break;
case SOCK_SEQPACKET:
LIST_INSERT_HEAD(&unp_sphead, unp, unp_link);
break;
default:
panic("uipc_attach");
}
if (locked == false)
UNP_LINK_WUNLOCK();
return (0);
}
static int
uipc_bindat(int fd, struct socket *so, struct sockaddr *nam, struct thread *td)
{
struct sockaddr_un *soun = (struct sockaddr_un *)nam;
struct vattr vattr;
int error, namelen;
struct nameidata nd;
struct unpcb *unp;
struct vnode *vp;
struct mount *mp;
cap_rights_t rights;
char *buf;
if (nam->sa_family != AF_UNIX)
return (EAFNOSUPPORT);
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_bind: unp == NULL"));
if (soun->sun_len > sizeof(struct sockaddr_un))
return (EINVAL);
namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path);
if (namelen <= 0)
return (EINVAL);
/*
* We don't allow simultaneous bind() calls on a single UNIX domain
* socket, so flag in-progress operations, and return an error if an
* operation is already in progress.
*
* Historically, we have not allowed a socket to be rebound, so this
* also returns an error. Not allowing re-binding simplifies the
* implementation and avoids a great many possible failure modes.
*/
UNP_PCB_LOCK(unp);
if (unp->unp_vnode != NULL) {
UNP_PCB_UNLOCK(unp);
return (EINVAL);
}
if (unp->unp_flags & UNP_BINDING) {
UNP_PCB_UNLOCK(unp);
return (EALREADY);
}
unp->unp_flags |= UNP_BINDING;
UNP_PCB_UNLOCK(unp);
buf = malloc(namelen + 1, M_TEMP, M_WAITOK);
bcopy(soun->sun_path, buf, namelen);
buf[namelen] = 0;
restart:
NDINIT_ATRIGHTS(&nd, CREATE, NOFOLLOW | LOCKPARENT | NOCACHE,
UIO_SYSSPACE, buf, fd, cap_rights_init_one(&rights, CAP_BINDAT));
/* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
error = namei(&nd);
if (error)
goto error;
vp = nd.ni_vp;
if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) {
NDFREE_PNBUF(&nd);
if (nd.ni_dvp == vp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
if (vp != NULL) {
vrele(vp);
error = EADDRINUSE;
goto error;
}
error = vn_start_write(NULL, &mp, V_XSLEEP | V_PCATCH);
if (error)
goto error;
goto restart;
}
VATTR_NULL(&vattr);
vattr.va_type = VSOCK;
vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_pd->pd_cmask);
#ifdef MAC
error = mac_vnode_check_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd,
&vattr);
#endif
if (error == 0) {
/*
* The prior lookup may have left LK_SHARED in cn_lkflags,
* and VOP_CREATE technically only requires the new vnode to
* be locked shared. Most filesystems will return the new vnode
* locked exclusive regardless, but we should explicitly
* specify that here since we require it and assert to that
* effect below.
*/
nd.ni_cnd.cn_lkflags = (nd.ni_cnd.cn_lkflags & ~LK_SHARED) |
LK_EXCLUSIVE;
error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
}
NDFREE_PNBUF(&nd);
if (error) {
VOP_VPUT_PAIR(nd.ni_dvp, NULL, true);
vn_finished_write(mp);
if (error == ERELOOKUP)
goto restart;
goto error;
}
vp = nd.ni_vp;
ASSERT_VOP_ELOCKED(vp, "uipc_bind");
soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK);
UNP_PCB_LOCK(unp);
VOP_UNP_BIND(vp, unp);
unp->unp_vnode = vp;
unp->unp_addr = soun;
unp->unp_flags &= ~UNP_BINDING;
UNP_PCB_UNLOCK(unp);
vref(vp);
VOP_VPUT_PAIR(nd.ni_dvp, &vp, true);
vn_finished_write(mp);
free(buf, M_TEMP);
return (0);
error:
UNP_PCB_LOCK(unp);
unp->unp_flags &= ~UNP_BINDING;
UNP_PCB_UNLOCK(unp);
free(buf, M_TEMP);
return (error);
}
static int
uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
{
return (uipc_bindat(AT_FDCWD, so, nam, td));
}
static int
uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
{
int error;
KASSERT(td == curthread, ("uipc_connect: td != curthread"));
error = unp_connect(so, nam, td);
return (error);
}
static int
uipc_connectat(int fd, struct socket *so, struct sockaddr *nam,
struct thread *td)
{
int error;
KASSERT(td == curthread, ("uipc_connectat: td != curthread"));
error = unp_connectat(fd, so, nam, td, false);
return (error);
}
static void
uipc_close(struct socket *so)
{
struct unpcb *unp, *unp2;
struct vnode *vp = NULL;
struct mtx *vplock;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_close: unp == NULL"));
vplock = NULL;
if ((vp = unp->unp_vnode) != NULL) {
vplock = mtx_pool_find(mtxpool_sleep, vp);
mtx_lock(vplock);
}
UNP_PCB_LOCK(unp);
if (vp && unp->unp_vnode == NULL) {
mtx_unlock(vplock);
vp = NULL;
}
if (vp != NULL) {
VOP_UNP_DETACH(vp);
unp->unp_vnode = NULL;
}
if ((unp2 = unp_pcb_lock_peer(unp)) != NULL)
unp_disconnect(unp, unp2);
else
UNP_PCB_UNLOCK(unp);
if (vp) {
mtx_unlock(vplock);
vrele(vp);
}
}
static int
uipc_connect2(struct socket *so1, struct socket *so2)
{
struct unpcb *unp, *unp2;
if (so1->so_type != so2->so_type)
return (EPROTOTYPE);
unp = so1->so_pcb;
KASSERT(unp != NULL, ("uipc_connect2: unp == NULL"));
unp2 = so2->so_pcb;
KASSERT(unp2 != NULL, ("uipc_connect2: unp2 == NULL"));
unp_pcb_lock_pair(unp, unp2);
unp_connect2(so1, so2);
unp_pcb_unlock_pair(unp, unp2);
return (0);
}
static void
uipc_detach(struct socket *so)
{
struct unpcb *unp, *unp2;
struct mtx *vplock;
struct vnode *vp;
int local_unp_rights;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_detach: unp == NULL"));
vp = NULL;
vplock = NULL;
if (!SOLISTENING(so))
unp_dispose(so);
UNP_LINK_WLOCK();
LIST_REMOVE(unp, unp_link);
if (unp->unp_gcflag & UNPGC_DEAD)
LIST_REMOVE(unp, unp_dead);
unp->unp_gencnt = ++unp_gencnt;
--unp_count;
UNP_LINK_WUNLOCK();
UNP_PCB_UNLOCK_ASSERT(unp);
restart:
if ((vp = unp->unp_vnode) != NULL) {
vplock = mtx_pool_find(mtxpool_sleep, vp);
mtx_lock(vplock);
}
UNP_PCB_LOCK(unp);
if (unp->unp_vnode != vp && unp->unp_vnode != NULL) {
if (vplock)
mtx_unlock(vplock);
UNP_PCB_UNLOCK(unp);
goto restart;
}
if ((vp = unp->unp_vnode) != NULL) {
VOP_UNP_DETACH(vp);
unp->unp_vnode = NULL;
}
if ((unp2 = unp_pcb_lock_peer(unp)) != NULL)
unp_disconnect(unp, unp2);
else
UNP_PCB_UNLOCK(unp);
UNP_REF_LIST_LOCK();
while (!LIST_EMPTY(&unp->unp_refs)) {
struct unpcb *ref = LIST_FIRST(&unp->unp_refs);
unp_pcb_hold(ref);
UNP_REF_LIST_UNLOCK();
MPASS(ref != unp);
UNP_PCB_UNLOCK_ASSERT(ref);
unp_drop(ref);
UNP_REF_LIST_LOCK();
}
UNP_REF_LIST_UNLOCK();
UNP_PCB_LOCK(unp);
local_unp_rights = unp_rights;
unp->unp_socket->so_pcb = NULL;
unp->unp_socket = NULL;
free(unp->unp_addr, M_SONAME);
unp->unp_addr = NULL;
if (!unp_pcb_rele(unp))
UNP_PCB_UNLOCK(unp);
if (vp) {
mtx_unlock(vplock);
vrele(vp);
}
if (local_unp_rights)
taskqueue_enqueue_timeout(taskqueue_thread, &unp_gc_task, -1);
switch (so->so_type) {
case SOCK_DGRAM:
/*
* Everything should have been unlinked/freed by unp_dispose()
* and/or unp_disconnect().
*/
MPASS(so->so_rcv.uxdg_peeked == NULL);
MPASS(STAILQ_EMPTY(&so->so_rcv.uxdg_mb));
MPASS(TAILQ_EMPTY(&so->so_rcv.uxdg_conns));
MPASS(STAILQ_EMPTY(&so->so_snd.uxdg_mb));
}
}
static int
uipc_disconnect(struct socket *so)
{
struct unpcb *unp, *unp2;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_disconnect: unp == NULL"));
UNP_PCB_LOCK(unp);
if ((unp2 = unp_pcb_lock_peer(unp)) != NULL)
unp_disconnect(unp, unp2);
else
UNP_PCB_UNLOCK(unp);
return (0);
}
static int
uipc_listen(struct socket *so, int backlog, struct thread *td)
{
struct unpcb *unp;
int error;
MPASS(so->so_type != SOCK_DGRAM);
/*
* Synchronize with concurrent connection attempts.
*/
error = 0;
unp = sotounpcb(so);
UNP_PCB_LOCK(unp);
if (unp->unp_conn != NULL || (unp->unp_flags & UNP_CONNECTING) != 0)
error = EINVAL;
else if (unp->unp_vnode == NULL)
error = EDESTADDRREQ;
if (error != 0) {
UNP_PCB_UNLOCK(unp);
return (error);
}
SOCK_LOCK(so);
error = solisten_proto_check(so);
if (error == 0) {
cru2xt(td, &unp->unp_peercred);
solisten_proto(so, backlog);
}
SOCK_UNLOCK(so);
UNP_PCB_UNLOCK(unp);
return (error);
}
static int
uipc_peeraddr(struct socket *so, struct sockaddr *ret)
{
struct unpcb *unp, *unp2;
const struct sockaddr *sa;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_peeraddr: unp == NULL"));
UNP_PCB_LOCK(unp);
unp2 = unp_pcb_lock_peer(unp);
if (unp2 != NULL) {
if (unp2->unp_addr != NULL)
sa = (struct sockaddr *)unp2->unp_addr;
else
sa = &sun_noname;
bcopy(sa, ret, sa->sa_len);
unp_pcb_unlock_pair(unp, unp2);
} else {
UNP_PCB_UNLOCK(unp);
sa = &sun_noname;
bcopy(sa, ret, sa->sa_len);
}
return (0);
}
static int
uipc_rcvd(struct socket *so, int flags)
{
struct unpcb *unp, *unp2;
struct socket *so2;
u_int mbcnt, sbcc;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("%s: unp == NULL", __func__));
KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET,
("%s: socktype %d", __func__, so->so_type));
/*
* Adjust backpressure on sender and wakeup any waiting to write.
*
* The unp lock is acquired to maintain the validity of the unp_conn
* pointer; no lock on unp2 is required as unp2->unp_socket will be
* static as long as we don't permit unp2 to disconnect from unp,
* which is prevented by the lock on unp. We cache values from
* so_rcv to avoid holding the so_rcv lock over the entire
* transaction on the remote so_snd.
*/
SOCKBUF_LOCK(&so->so_rcv);
mbcnt = so->so_rcv.sb_mbcnt;
sbcc = sbavail(&so->so_rcv);
SOCKBUF_UNLOCK(&so->so_rcv);
/*
* There is a benign race condition at this point. If we're planning to
* clear SB_STOP, but uipc_send is called on the connected socket at
* this instant, it might add data to the sockbuf and set SB_STOP. Then
* we would erroneously clear SB_STOP below, even though the sockbuf is
* full. The race is benign because the only ill effect is to allow the
* sockbuf to exceed its size limit, and the size limits are not
* strictly guaranteed anyway.
*/
UNP_PCB_LOCK(unp);
unp2 = unp->unp_conn;
if (unp2 == NULL) {
UNP_PCB_UNLOCK(unp);
return (0);
}
so2 = unp2->unp_socket;
SOCKBUF_LOCK(&so2->so_snd);
if (sbcc < so2->so_snd.sb_hiwat && mbcnt < so2->so_snd.sb_mbmax)
so2->so_snd.sb_flags &= ~SB_STOP;
sowwakeup_locked(so2);
UNP_PCB_UNLOCK(unp);
return (0);
}
static int
uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
struct mbuf *control, struct thread *td)
{
struct unpcb *unp, *unp2;
struct socket *so2;
u_int mbcnt, sbcc;
int error;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("%s: unp == NULL", __func__));
KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET,
("%s: socktype %d", __func__, so->so_type));
error = 0;
if (flags & PRUS_OOB) {
error = EOPNOTSUPP;
goto release;
}
if (control != NULL &&
(error = unp_internalize(&control, td, NULL, NULL, NULL)))
goto release;
unp2 = NULL;
if ((so->so_state & SS_ISCONNECTED) == 0) {
if (nam != NULL) {
if ((error = unp_connect(so, nam, td)) != 0)
goto out;
} else {
error = ENOTCONN;
goto out;
}
}
UNP_PCB_LOCK(unp);
if ((unp2 = unp_pcb_lock_peer(unp)) == NULL) {
UNP_PCB_UNLOCK(unp);
error = ENOTCONN;
goto out;
} else if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
unp_pcb_unlock_pair(unp, unp2);
error = EPIPE;
goto out;
}
UNP_PCB_UNLOCK(unp);
if ((so2 = unp2->unp_socket) == NULL) {
UNP_PCB_UNLOCK(unp2);
error = ENOTCONN;
goto out;
}
SOCKBUF_LOCK(&so2->so_rcv);
if (unp2->unp_flags & UNP_WANTCRED_MASK) {
/*
* Credentials are passed only once on SOCK_STREAM and
* SOCK_SEQPACKET (LOCAL_CREDS => WANTCRED_ONESHOT), or
* forever (LOCAL_CREDS_PERSISTENT => WANTCRED_ALWAYS).
*/
control = unp_addsockcred(td, control, unp2->unp_flags, NULL,
NULL, NULL);
unp2->unp_flags &= ~UNP_WANTCRED_ONESHOT;
}
/*
* Send to paired receive port and wake up readers. Don't
* check for space available in the receive buffer if we're
* attaching ancillary data; Unix domain sockets only check
* for space in the sending sockbuf, and that check is
* performed one level up the stack. At that level we cannot
* precisely account for the amount of buffer space used
* (e.g., because control messages are not yet internalized).
*/
switch (so->so_type) {
case SOCK_STREAM:
if (control != NULL) {
sbappendcontrol_locked(&so2->so_rcv,
m->m_len > 0 ? m : NULL, control, flags);
control = NULL;
} else
sbappend_locked(&so2->so_rcv, m, flags);
break;
case SOCK_SEQPACKET:
if (sbappendaddr_nospacecheck_locked(&so2->so_rcv,
&sun_noname, m, control))
control = NULL;
break;
}
mbcnt = so2->so_rcv.sb_mbcnt;
sbcc = sbavail(&so2->so_rcv);
if (sbcc)
sorwakeup_locked(so2);
else
SOCKBUF_UNLOCK(&so2->so_rcv);
/*
* The PCB lock on unp2 protects the SB_STOP flag. Without it,
* it would be possible for uipc_rcvd to be called at this
* point, drain the receiving sockbuf, clear SB_STOP, and then
* we would set SB_STOP below. That could lead to an empty
* sockbuf having SB_STOP set
*/
SOCKBUF_LOCK(&so->so_snd);
if (sbcc >= so->so_snd.sb_hiwat || mbcnt >= so->so_snd.sb_mbmax)
so->so_snd.sb_flags |= SB_STOP;
SOCKBUF_UNLOCK(&so->so_snd);
UNP_PCB_UNLOCK(unp2);
m = NULL;
out:
/*
* PRUS_EOF is equivalent to pr_send followed by pr_shutdown.
*/
if (flags & PRUS_EOF) {
UNP_PCB_LOCK(unp);
socantsendmore(so);
unp_shutdown(unp);
UNP_PCB_UNLOCK(unp);
}
if (control != NULL && error != 0)
unp_scan(control, unp_freerights);
release:
if (control != NULL)
m_freem(control);
/*
* In case of PRUS_NOTREADY, uipc_ready() is responsible
* for freeing memory.
*/
if (m != NULL && (flags & PRUS_NOTREADY) == 0)
m_freem(m);
return (error);
}
/* PF_UNIX/SOCK_DGRAM version of sbspace() */
static inline bool
uipc_dgram_sbspace(struct sockbuf *sb, u_int cc, u_int mbcnt)
{
u_int bleft, mleft;
/*
* Negative space may happen if send(2) is followed by
* setsockopt(SO_SNDBUF/SO_RCVBUF) that shrinks maximum.
*/
if (__predict_false(sb->sb_hiwat < sb->uxdg_cc ||
sb->sb_mbmax < sb->uxdg_mbcnt))
return (false);
if (__predict_false(sb->sb_state & SBS_CANTRCVMORE))
return (false);
bleft = sb->sb_hiwat - sb->uxdg_cc;
mleft = sb->sb_mbmax - sb->uxdg_mbcnt;
return (bleft >= cc && mleft >= mbcnt);
}
/*
* PF_UNIX/SOCK_DGRAM send
*
* Allocate a record consisting of 3 mbufs in the sequence of
* from -> control -> data and append it to the socket buffer.
*
* The first mbuf carries sender's name and is a pkthdr that stores
* overall length of datagram, its memory consumption and control length.
*/
#define ctllen PH_loc.thirtytwo[1]
_Static_assert(offsetof(struct pkthdr, memlen) + sizeof(u_int) <=
offsetof(struct pkthdr, ctllen), "unix/dgram can not store ctllen");
static int
uipc_sosend_dgram(struct socket *so, struct sockaddr *addr, struct uio *uio,
struct mbuf *m, struct mbuf *c, int flags, struct thread *td)
{
struct unpcb *unp, *unp2;
const struct sockaddr *from;
struct socket *so2;
struct sockbuf *sb;
struct mbuf *f, *clast;
u_int cc, ctl, mbcnt;
u_int dcc __diagused, dctl __diagused, dmbcnt __diagused;
int error;
MPASS((uio != NULL && m == NULL) || (m != NULL && uio == NULL));
error = 0;
f = NULL;
ctl = 0;
if (__predict_false(flags & MSG_OOB)) {
error = EOPNOTSUPP;
goto out;
}
if (m == NULL) {
if (__predict_false(uio->uio_resid > unpdg_maxdgram)) {
error = EMSGSIZE;
goto out;
}
m = m_uiotombuf(uio, M_WAITOK, 0, max_hdr, M_PKTHDR);
if (__predict_false(m == NULL)) {
error = EFAULT;
goto out;
}
f = m_gethdr(M_WAITOK, MT_SONAME);
cc = m->m_pkthdr.len;
mbcnt = MSIZE + m->m_pkthdr.memlen;
if (c != NULL &&
(error = unp_internalize(&c, td, &clast, &ctl, &mbcnt)))
goto out;
} else {
/* pr_sosend() with mbuf usually is a kernel thread. */
M_ASSERTPKTHDR(m);
if (__predict_false(c != NULL))
panic("%s: control from a kernel thread", __func__);
if (__predict_false(m->m_pkthdr.len > unpdg_maxdgram)) {
error = EMSGSIZE;
goto out;
}
if ((f = m_gethdr(M_NOWAIT, MT_SONAME)) == NULL) {
error = ENOBUFS;
goto out;
}
/* Condition the foreign mbuf to our standards. */
m_clrprotoflags(m);
m_tag_delete_chain(m, NULL);
m->m_pkthdr.rcvif = NULL;
m->m_pkthdr.flowid = 0;
m->m_pkthdr.csum_flags = 0;
m->m_pkthdr.fibnum = 0;
m->m_pkthdr.rsstype = 0;
cc = m->m_pkthdr.len;
mbcnt = MSIZE;
for (struct mbuf *mb = m; mb != NULL; mb = mb->m_next) {
mbcnt += MSIZE;
if (mb->m_flags & M_EXT)
mbcnt += mb->m_ext.ext_size;
}
}
unp = sotounpcb(so);
MPASS(unp);
/*
* XXXGL: would be cool to fully remove so_snd out of the equation
* and avoid this lock, which is not only extraneous, but also being
* released, thus still leaving possibility for a race. We can easily
* handle SBS_CANTSENDMORE/SS_ISCONNECTED complement in unpcb, but it
* is more difficult to invent something to handle so_error.
*/
error = SOCK_IO_SEND_LOCK(so, SBLOCKWAIT(flags));
if (error)
goto out2;
SOCK_SENDBUF_LOCK(so);
if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
SOCK_SENDBUF_UNLOCK(so);
error = EPIPE;
goto out3;
}
if (so->so_error != 0) {
error = so->so_error;
so->so_error = 0;
SOCK_SENDBUF_UNLOCK(so);
goto out3;
}
if (((so->so_state & SS_ISCONNECTED) == 0) && addr == NULL) {
SOCK_SENDBUF_UNLOCK(so);
error = EDESTADDRREQ;
goto out3;
}
SOCK_SENDBUF_UNLOCK(so);
if (addr != NULL) {
if ((error = unp_connectat(AT_FDCWD, so, addr, td, true)))
goto out3;
UNP_PCB_LOCK_ASSERT(unp);
unp2 = unp->unp_conn;
UNP_PCB_LOCK_ASSERT(unp2);
} else {
UNP_PCB_LOCK(unp);
unp2 = unp_pcb_lock_peer(unp);
if (unp2 == NULL) {
UNP_PCB_UNLOCK(unp);
error = ENOTCONN;
goto out3;
}
}
if (unp2->unp_flags & UNP_WANTCRED_MASK)
c = unp_addsockcred(td, c, unp2->unp_flags, &clast, &ctl,
&mbcnt);
if (unp->unp_addr != NULL)
from = (struct sockaddr *)unp->unp_addr;
else
from = &sun_noname;
f->m_len = from->sa_len;
MPASS(from->sa_len <= MLEN);
bcopy(from, mtod(f, void *), from->sa_len);
ctl += f->m_len;
/*
* Concatenate mbufs: from -> control -> data.
* Save overall cc and mbcnt in "from" mbuf.
*/
if (c != NULL) {
#ifdef INVARIANTS
struct mbuf *mc;
for (mc = c; mc->m_next != NULL; mc = mc->m_next);
MPASS(mc == clast);
#endif
f->m_next = c;
clast->m_next = m;
c = NULL;
} else
f->m_next = m;
m = NULL;
#ifdef INVARIANTS
dcc = dctl = dmbcnt = 0;
for (struct mbuf *mb = f; mb != NULL; mb = mb->m_next) {
if (mb->m_type == MT_DATA)
dcc += mb->m_len;
else
dctl += mb->m_len;
dmbcnt += MSIZE;
if (mb->m_flags & M_EXT)
dmbcnt += mb->m_ext.ext_size;
}
MPASS(dcc == cc);
MPASS(dctl == ctl);
MPASS(dmbcnt == mbcnt);
#endif
f->m_pkthdr.len = cc + ctl;
f->m_pkthdr.memlen = mbcnt;
f->m_pkthdr.ctllen = ctl;
/*
* Destination socket buffer selection.
*
* Unconnected sends, when !(so->so_state & SS_ISCONNECTED) and the
* destination address is supplied, create a temporary connection for
* the run time of the function (see call to unp_connectat() above and
* to unp_disconnect() below). We distinguish them by condition of
* (addr != NULL). We intentionally avoid adding 'bool connected' for
* that condition, since, again, through the run time of this code we
* are always connected. For such "unconnected" sends, the destination
* buffer would be the receive buffer of destination socket so2.
*
* For connected sends, data lands on the send buffer of the sender's
* socket "so". Then, if we just added the very first datagram
* on this send buffer, we need to add the send buffer on to the
* receiving socket's buffer list. We put ourselves on top of the
* list. Such logic gives infrequent senders priority over frequent
* senders.
*
* Note on byte count management. As long as event methods kevent(2),
* select(2) are not protocol specific (yet), we need to maintain
* meaningful values on the receive buffer. So, the receive buffer
* would accumulate counters from all connected buffers potentially
* having sb_ccc > sb_hiwat or sb_mbcnt > sb_mbmax.
*/
so2 = unp2->unp_socket;
sb = (addr == NULL) ? &so->so_snd : &so2->so_rcv;
SOCK_RECVBUF_LOCK(so2);
if (uipc_dgram_sbspace(sb, cc + ctl, mbcnt)) {
if (addr == NULL && STAILQ_EMPTY(&sb->uxdg_mb))
TAILQ_INSERT_HEAD(&so2->so_rcv.uxdg_conns, &so->so_snd,
uxdg_clist);
STAILQ_INSERT_TAIL(&sb->uxdg_mb, f, m_stailqpkt);
sb->uxdg_cc += cc + ctl;
sb->uxdg_ctl += ctl;
sb->uxdg_mbcnt += mbcnt;
so2->so_rcv.sb_acc += cc + ctl;
so2->so_rcv.sb_ccc += cc + ctl;
so2->so_rcv.sb_ctl += ctl;
so2->so_rcv.sb_mbcnt += mbcnt;
sorwakeup_locked(so2);
f = NULL;
} else {
soroverflow_locked(so2);
error = ENOBUFS;
if (f->m_next->m_type == MT_CONTROL) {
c = f->m_next;
f->m_next = NULL;
}
}
if (addr != NULL)
unp_disconnect(unp, unp2);
else
unp_pcb_unlock_pair(unp, unp2);
td->td_ru.ru_msgsnd++;
out3:
SOCK_IO_SEND_UNLOCK(so);
out2:
if (c)
unp_scan(c, unp_freerights);
out:
if (f)
m_freem(f);
if (c)
m_freem(c);
if (m)
m_freem(m);
return (error);
}
/*
* PF_UNIX/SOCK_DGRAM receive with MSG_PEEK.
* The mbuf has already been unlinked from the uxdg_mb of socket buffer
* and needs to be linked onto uxdg_peeked of receive socket buffer.
*/
static int
uipc_peek_dgram(struct socket *so, struct mbuf *m, struct sockaddr **psa,
struct uio *uio, struct mbuf **controlp, int *flagsp)
{
ssize_t len = 0;
int error;
so->so_rcv.uxdg_peeked = m;
so->so_rcv.uxdg_cc += m->m_pkthdr.len;
so->so_rcv.uxdg_ctl += m->m_pkthdr.ctllen;
so->so_rcv.uxdg_mbcnt += m->m_pkthdr.memlen;
SOCK_RECVBUF_UNLOCK(so);
KASSERT(m->m_type == MT_SONAME, ("m->m_type == %d", m->m_type));
if (psa != NULL)
*psa = sodupsockaddr(mtod(m, struct sockaddr *), M_WAITOK);
m = m->m_next;
KASSERT(m, ("%s: no data or control after soname", __func__));
/*
* With MSG_PEEK the control isn't executed, just copied.
*/
while (m != NULL && m->m_type == MT_CONTROL) {
if (controlp != NULL) {
*controlp = m_copym(m, 0, m->m_len, M_WAITOK);
controlp = &(*controlp)->m_next;
}
m = m->m_next;
}
KASSERT(m == NULL || m->m_type == MT_DATA,
("%s: not MT_DATA mbuf %p", __func__, m));
while (m != NULL && uio->uio_resid > 0) {
len = uio->uio_resid;
if (len > m->m_len)
len = m->m_len;
error = uiomove(mtod(m, char *), (int)len, uio);
if (error) {
SOCK_IO_RECV_UNLOCK(so);
return (error);
}
if (len == m->m_len)
m = m->m_next;
}
SOCK_IO_RECV_UNLOCK(so);
if (flagsp != NULL) {
if (m != NULL) {
if (*flagsp & MSG_TRUNC) {
/* Report real length of the packet */
uio->uio_resid -= m_length(m, NULL) - len;
}
*flagsp |= MSG_TRUNC;
} else
*flagsp &= ~MSG_TRUNC;
}
return (0);
}
/*
* PF_UNIX/SOCK_DGRAM receive
*/
static int
uipc_soreceive_dgram(struct socket *so, struct sockaddr **psa, struct uio *uio,
struct mbuf **mp0, struct mbuf **controlp, int *flagsp)
{
struct sockbuf *sb = NULL;
struct mbuf *m;
int flags, error;
ssize_t len = 0;
bool nonblock;
MPASS(mp0 == NULL);
if (psa != NULL)
*psa = NULL;
if (controlp != NULL)
*controlp = NULL;
flags = flagsp != NULL ? *flagsp : 0;
nonblock = (so->so_state & SS_NBIO) ||
(flags & (MSG_DONTWAIT | MSG_NBIO));
error = SOCK_IO_RECV_LOCK(so, SBLOCKWAIT(flags));
if (__predict_false(error))
return (error);
/*
* Loop blocking while waiting for a datagram. Prioritize connected
* peers over unconnected sends. Set sb to selected socket buffer
* containing an mbuf on exit from the wait loop. A datagram that
* had already been peeked at has top priority.
*/
SOCK_RECVBUF_LOCK(so);
while ((m = so->so_rcv.uxdg_peeked) == NULL &&
(sb = TAILQ_FIRST(&so->so_rcv.uxdg_conns)) == NULL &&
(m = STAILQ_FIRST(&so->so_rcv.uxdg_mb)) == NULL) {
if (so->so_error) {
error = so->so_error;
if (!(flags & MSG_PEEK))
so->so_error = 0;
SOCK_RECVBUF_UNLOCK(so);
SOCK_IO_RECV_UNLOCK(so);
return (error);
}
if (so->so_rcv.sb_state & SBS_CANTRCVMORE ||
uio->uio_resid == 0) {
SOCK_RECVBUF_UNLOCK(so);
SOCK_IO_RECV_UNLOCK(so);
return (0);
}
if (nonblock) {
SOCK_RECVBUF_UNLOCK(so);
SOCK_IO_RECV_UNLOCK(so);
return (EWOULDBLOCK);
}
error = sbwait(so, SO_RCV);
if (error) {
SOCK_RECVBUF_UNLOCK(so);
SOCK_IO_RECV_UNLOCK(so);
return (error);
}
}
if (sb == NULL)
sb = &so->so_rcv;
else if (m == NULL)
m = STAILQ_FIRST(&sb->uxdg_mb);
else
MPASS(m == so->so_rcv.uxdg_peeked);
MPASS(sb->uxdg_cc > 0);
M_ASSERTPKTHDR(m);
KASSERT(m->m_type == MT_SONAME, ("m->m_type == %d", m->m_type));
if (uio->uio_td)
uio->uio_td->td_ru.ru_msgrcv++;
if (__predict_true(m != so->so_rcv.uxdg_peeked)) {
STAILQ_REMOVE_HEAD(&sb->uxdg_mb, m_stailqpkt);
if (STAILQ_EMPTY(&sb->uxdg_mb) && sb != &so->so_rcv)
TAILQ_REMOVE(&so->so_rcv.uxdg_conns, sb, uxdg_clist);
} else
so->so_rcv.uxdg_peeked = NULL;
sb->uxdg_cc -= m->m_pkthdr.len;
sb->uxdg_ctl -= m->m_pkthdr.ctllen;
sb->uxdg_mbcnt -= m->m_pkthdr.memlen;
if (__predict_false(flags & MSG_PEEK))
return (uipc_peek_dgram(so, m, psa, uio, controlp, flagsp));
so->so_rcv.sb_acc -= m->m_pkthdr.len;
so->so_rcv.sb_ccc -= m->m_pkthdr.len;
so->so_rcv.sb_ctl -= m->m_pkthdr.ctllen;
so->so_rcv.sb_mbcnt -= m->m_pkthdr.memlen;
SOCK_RECVBUF_UNLOCK(so);
if (psa != NULL)
*psa = sodupsockaddr(mtod(m, struct sockaddr *), M_WAITOK);
m = m_free(m);
KASSERT(m, ("%s: no data or control after soname", __func__));
/*
* Packet to copyout() is now in 'm' and it is disconnected from the
* queue.
*
* Process one or more MT_CONTROL mbufs present before any data mbufs
* in the first mbuf chain on the socket buffer. We call into the
* unp_externalize() to perform externalization (or freeing if
* controlp == NULL). In some cases there can be only MT_CONTROL mbufs
* without MT_DATA mbufs.
*/
while (m != NULL && m->m_type == MT_CONTROL) {
struct mbuf *cm;
/* XXXGL: unp_externalize() is also dom_externalize() KBI and
* it frees whole chain, so we must disconnect the mbuf.
*/
cm = m; m = m->m_next; cm->m_next = NULL;
error = unp_externalize(cm, controlp, flags);
if (error != 0) {
SOCK_IO_RECV_UNLOCK(so);
unp_scan(m, unp_freerights);
m_freem(m);
return (error);
}
if (controlp != NULL) {
while (*controlp != NULL)
controlp = &(*controlp)->m_next;
}
}
KASSERT(m == NULL || m->m_type == MT_DATA,
("%s: not MT_DATA mbuf %p", __func__, m));
while (m != NULL && uio->uio_resid > 0) {
len = uio->uio_resid;
if (len > m->m_len)
len = m->m_len;
error = uiomove(mtod(m, char *), (int)len, uio);
if (error) {
SOCK_IO_RECV_UNLOCK(so);
m_freem(m);
return (error);
}
if (len == m->m_len)
m = m_free(m);
else {
m->m_data += len;
m->m_len -= len;
}
}
SOCK_IO_RECV_UNLOCK(so);
if (m != NULL) {
if (flagsp != NULL) {
if (flags & MSG_TRUNC) {
/* Report real length of the packet */
uio->uio_resid -= m_length(m, NULL);
}
*flagsp |= MSG_TRUNC;
}
m_freem(m);
} else if (flagsp != NULL)
*flagsp &= ~MSG_TRUNC;
return (0);
}
static bool
uipc_ready_scan(struct socket *so, struct mbuf *m, int count, int *errorp)
{
struct mbuf *mb, *n;
struct sockbuf *sb;
SOCK_LOCK(so);
if (SOLISTENING(so)) {
SOCK_UNLOCK(so);
return (false);
}
mb = NULL;
sb = &so->so_rcv;
SOCKBUF_LOCK(sb);
if (sb->sb_fnrdy != NULL) {
for (mb = sb->sb_mb, n = mb->m_nextpkt; mb != NULL;) {
if (mb == m) {
*errorp = sbready(sb, m, count);
break;
}
mb = mb->m_next;
if (mb == NULL) {
mb = n;
if (mb != NULL)
n = mb->m_nextpkt;
}
}
}
SOCKBUF_UNLOCK(sb);
SOCK_UNLOCK(so);
return (mb != NULL);
}
static int
uipc_ready(struct socket *so, struct mbuf *m, int count)
{
struct unpcb *unp, *unp2;
struct socket *so2;
int error, i;
unp = sotounpcb(so);
KASSERT(so->so_type == SOCK_STREAM,
("%s: unexpected socket type for %p", __func__, so));
UNP_PCB_LOCK(unp);
if ((unp2 = unp_pcb_lock_peer(unp)) != NULL) {
UNP_PCB_UNLOCK(unp);
so2 = unp2->unp_socket;
SOCKBUF_LOCK(&so2->so_rcv);
if ((error = sbready(&so2->so_rcv, m, count)) == 0)
sorwakeup_locked(so2);
else
SOCKBUF_UNLOCK(&so2->so_rcv);
UNP_PCB_UNLOCK(unp2);
return (error);
}
UNP_PCB_UNLOCK(unp);
/*
* The receiving socket has been disconnected, but may still be valid.
* In this case, the now-ready mbufs are still present in its socket
* buffer, so perform an exhaustive search before giving up and freeing
* the mbufs.
*/
UNP_LINK_RLOCK();
LIST_FOREACH(unp, &unp_shead, unp_link) {
if (uipc_ready_scan(unp->unp_socket, m, count, &error))
break;
}
UNP_LINK_RUNLOCK();
if (unp == NULL) {
for (i = 0; i < count; i++)
m = m_free(m);
error = ECONNRESET;
}
return (error);
}
static int
uipc_sense(struct socket *so, struct stat *sb)
{
struct unpcb *unp;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_sense: unp == NULL"));
sb->st_blksize = so->so_snd.sb_hiwat;
sb->st_dev = NODEV;
sb->st_ino = unp->unp_ino;
return (0);
}
static int
uipc_shutdown(struct socket *so, enum shutdown_how how)
{
struct unpcb *unp = sotounpcb(so);
int error;
SOCK_LOCK(so);
if (SOLISTENING(so)) {
if (how != SHUT_WR) {
so->so_error = ECONNABORTED;
solisten_wakeup(so); /* unlocks so */
} else
SOCK_UNLOCK(so);
return (ENOTCONN);
} else if ((so->so_state &
(SS_ISCONNECTED | SS_ISCONNECTING | SS_ISDISCONNECTING)) == 0) {
/*
* POSIX mandates us to just return ENOTCONN when shutdown(2) is
* invoked on a datagram sockets, however historically we would
* actually tear socket down. This is known to be leveraged by
* some applications to unblock process waiting in recv(2) by
* other process that it shares that socket with. Try to meet
* both backward-compatibility and POSIX requirements by forcing
* ENOTCONN but still flushing buffers and performing wakeup(9).
*
* XXXGL: it remains unknown what applications expect this
* behavior and is this isolated to unix/dgram or inet/dgram or
* both. See: D10351, D3039.
*/
error = ENOTCONN;
if (so->so_type != SOCK_DGRAM) {
SOCK_UNLOCK(so);
return (error);
}
} else
error = 0;
SOCK_UNLOCK(so);
switch (how) {
case SHUT_RD:
socantrcvmore(so);
unp_dispose(so);
break;
case SHUT_RDWR:
socantrcvmore(so);
unp_dispose(so);
/* FALLTHROUGH */
case SHUT_WR:
UNP_PCB_LOCK(unp);
socantsendmore(so);
unp_shutdown(unp);
UNP_PCB_UNLOCK(unp);
}
wakeup(&so->so_timeo);
return (error);
}
static int
uipc_sockaddr(struct socket *so, struct sockaddr *ret)
{
struct unpcb *unp;
const struct sockaddr *sa;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_sockaddr: unp == NULL"));
UNP_PCB_LOCK(unp);
if (unp->unp_addr != NULL)
sa = (struct sockaddr *) unp->unp_addr;
else
sa = &sun_noname;
bcopy(sa, ret, sa->sa_len);
UNP_PCB_UNLOCK(unp);
return (0);
}
static int
uipc_ctloutput(struct socket *so, struct sockopt *sopt)
{
struct unpcb *unp;
struct xucred xu;
int error, optval;
if (sopt->sopt_level != SOL_LOCAL)
return (EINVAL);
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_ctloutput: unp == NULL"));
error = 0;
switch (sopt->sopt_dir) {
case SOPT_GET:
switch (sopt->sopt_name) {
case LOCAL_PEERCRED:
UNP_PCB_LOCK(unp);
if (unp->unp_flags & UNP_HAVEPC)
xu = unp->unp_peercred;
else {
if (so->so_type == SOCK_STREAM)
error = ENOTCONN;
else
error = EINVAL;
}
UNP_PCB_UNLOCK(unp);
if (error == 0)
error = sooptcopyout(sopt, &xu, sizeof(xu));
break;
case LOCAL_CREDS:
/* Unlocked read. */
optval = unp->unp_flags & UNP_WANTCRED_ONESHOT ? 1 : 0;
error = sooptcopyout(sopt, &optval, sizeof(optval));
break;
case LOCAL_CREDS_PERSISTENT:
/* Unlocked read. */
optval = unp->unp_flags & UNP_WANTCRED_ALWAYS ? 1 : 0;
error = sooptcopyout(sopt, &optval, sizeof(optval));
break;
default:
error = EOPNOTSUPP;
break;
}
break;
case SOPT_SET:
switch (sopt->sopt_name) {
case LOCAL_CREDS:
case LOCAL_CREDS_PERSISTENT:
error = sooptcopyin(sopt, &optval, sizeof(optval),
sizeof(optval));
if (error)
break;
#define OPTSET(bit, exclusive) do { \
UNP_PCB_LOCK(unp); \
if (optval) { \
if ((unp->unp_flags & (exclusive)) != 0) { \
UNP_PCB_UNLOCK(unp); \
error = EINVAL; \
break; \
} \
unp->unp_flags |= (bit); \
} else \
unp->unp_flags &= ~(bit); \
UNP_PCB_UNLOCK(unp); \
} while (0)
switch (sopt->sopt_name) {
case LOCAL_CREDS:
OPTSET(UNP_WANTCRED_ONESHOT, UNP_WANTCRED_ALWAYS);
break;
case LOCAL_CREDS_PERSISTENT:
OPTSET(UNP_WANTCRED_ALWAYS, UNP_WANTCRED_ONESHOT);
break;
default:
break;
}
break;
#undef OPTSET
default:
error = ENOPROTOOPT;
break;
}
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}
static int
unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
{
return (unp_connectat(AT_FDCWD, so, nam, td, false));
}
static int
unp_connectat(int fd, struct socket *so, struct sockaddr *nam,
struct thread *td, bool return_locked)
{
struct mtx *vplock;
struct sockaddr_un *soun;
struct vnode *vp;
struct socket *so2;
struct unpcb *unp, *unp2, *unp3;
struct nameidata nd;
char buf[SOCK_MAXADDRLEN];
struct sockaddr *sa;
cap_rights_t rights;
int error, len;
bool connreq;
if (nam->sa_family != AF_UNIX)
return (EAFNOSUPPORT);
if (nam->sa_len > sizeof(struct sockaddr_un))
return (EINVAL);
len = nam->sa_len - offsetof(struct sockaddr_un, sun_path);
if (len <= 0)
return (EINVAL);
soun = (struct sockaddr_un *)nam;
bcopy(soun->sun_path, buf, len);
buf[len] = 0;
error = 0;
unp = sotounpcb(so);
UNP_PCB_LOCK(unp);
for (;;) {
/*
* Wait for connection state to stabilize. If a connection
* already exists, give up. For datagram sockets, which permit
* multiple consecutive connect(2) calls, upper layers are
* responsible for disconnecting in advance of a subsequent
* connect(2), but this is not synchronized with PCB connection
* state.
*
* Also make sure that no threads are currently attempting to
* lock the peer socket, to ensure that unp_conn cannot
* transition between two valid sockets while locks are dropped.
*/
if (SOLISTENING(so))
error = EOPNOTSUPP;
else if (unp->unp_conn != NULL)
error = EISCONN;
else if ((unp->unp_flags & UNP_CONNECTING) != 0) {
error = EALREADY;
}
if (error != 0) {
UNP_PCB_UNLOCK(unp);
return (error);
}
if (unp->unp_pairbusy > 0) {
unp->unp_flags |= UNP_WAITING;
mtx_sleep(unp, UNP_PCB_LOCKPTR(unp), 0, "unpeer", 0);
continue;
}
break;
}
unp->unp_flags |= UNP_CONNECTING;
UNP_PCB_UNLOCK(unp);
connreq = (so->so_proto->pr_flags & PR_CONNREQUIRED) != 0;
if (connreq)
sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
else
sa = NULL;
NDINIT_ATRIGHTS(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF,
UIO_SYSSPACE, buf, fd, cap_rights_init_one(&rights, CAP_CONNECTAT));
error = namei(&nd);
if (error)
vp = NULL;
else
vp = nd.ni_vp;
ASSERT_VOP_LOCKED(vp, "unp_connect");
if (error)
goto bad;
NDFREE_PNBUF(&nd);
if (vp->v_type != VSOCK) {
error = ENOTSOCK;
goto bad;
}
#ifdef MAC
error = mac_vnode_check_open(td->td_ucred, vp, VWRITE | VREAD);
if (error)
goto bad;
#endif
error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td);
if (error)
goto bad;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
vplock = mtx_pool_find(mtxpool_sleep, vp);
mtx_lock(vplock);
VOP_UNP_CONNECT(vp, &unp2);
if (unp2 == NULL) {
error = ECONNREFUSED;
goto bad2;
}
so2 = unp2->unp_socket;
if (so->so_type != so2->so_type) {
error = EPROTOTYPE;
goto bad2;
}
if (connreq) {
if (SOLISTENING(so2)) {
CURVNET_SET(so2->so_vnet);
so2 = sonewconn(so2, 0);
CURVNET_RESTORE();
} else
so2 = NULL;
if (so2 == NULL) {
error = ECONNREFUSED;
goto bad2;
}
unp3 = sotounpcb(so2);
unp_pcb_lock_pair(unp2, unp3);
if (unp2->unp_addr != NULL) {
bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len);
unp3->unp_addr = (struct sockaddr_un *) sa;
sa = NULL;
}
unp_copy_peercred(td, unp3, unp, unp2);
UNP_PCB_UNLOCK(unp2);
unp2 = unp3;
/*
* It is safe to block on the PCB lock here since unp2 is
* nascent and cannot be connected to any other sockets.
*/
UNP_PCB_LOCK(unp);
#ifdef MAC
mac_socketpeer_set_from_socket(so, so2);
mac_socketpeer_set_from_socket(so2, so);
#endif
} else {
unp_pcb_lock_pair(unp, unp2);
}
KASSERT(unp2 != NULL && so2 != NULL && unp2->unp_socket == so2 &&
sotounpcb(so2) == unp2,
("%s: unp2 %p so2 %p", __func__, unp2, so2));
unp_connect2(so, so2);
KASSERT((unp->unp_flags & UNP_CONNECTING) != 0,
("%s: unp %p has UNP_CONNECTING clear", __func__, unp));
unp->unp_flags &= ~UNP_CONNECTING;
if (!return_locked)
unp_pcb_unlock_pair(unp, unp2);
bad2:
mtx_unlock(vplock);
bad:
if (vp != NULL) {
/*
* If we are returning locked (called via uipc_sosend_dgram()),
* we need to be sure that vput() won't sleep. This is
* guaranteed by VOP_UNP_CONNECT() call above and unp2 lock.
* SOCK_STREAM/SEQPACKET can't request return_locked (yet).
*/
MPASS(!(return_locked && connreq));
vput(vp);
}
free(sa, M_SONAME);
if (__predict_false(error)) {
UNP_PCB_LOCK(unp);
KASSERT((unp->unp_flags & UNP_CONNECTING) != 0,
("%s: unp %p has UNP_CONNECTING clear", __func__, unp));
unp->unp_flags &= ~UNP_CONNECTING;
UNP_PCB_UNLOCK(unp);
}
return (error);
}
/*
* Set socket peer credentials at connection time.
*
* The client's PCB credentials are copied from its process structure. The
* server's PCB credentials are copied from the socket on which it called
* listen(2). uipc_listen cached that process's credentials at the time.
*/
void
unp_copy_peercred(struct thread *td, struct unpcb *client_unp,
struct unpcb *server_unp, struct unpcb *listen_unp)
{
cru2xt(td, &client_unp->unp_peercred);
client_unp->unp_flags |= UNP_HAVEPC;
memcpy(&server_unp->unp_peercred, &listen_unp->unp_peercred,
sizeof(server_unp->unp_peercred));
server_unp->unp_flags |= UNP_HAVEPC;
client_unp->unp_flags |= (listen_unp->unp_flags & UNP_WANTCRED_MASK);
}
static void
unp_connect2(struct socket *so, struct socket *so2)
{
struct unpcb *unp;
struct unpcb *unp2;
MPASS(so2->so_type == so->so_type);
unp = sotounpcb(so);
KASSERT(unp != NULL, ("unp_connect2: unp == NULL"));
unp2 = sotounpcb(so2);
KASSERT(unp2 != NULL, ("unp_connect2: unp2 == NULL"));
UNP_PCB_LOCK_ASSERT(unp);
UNP_PCB_LOCK_ASSERT(unp2);
KASSERT(unp->unp_conn == NULL,
("%s: socket %p is already connected", __func__, unp));
unp->unp_conn = unp2;
unp_pcb_hold(unp2);
unp_pcb_hold(unp);
switch (so->so_type) {
case SOCK_DGRAM:
UNP_REF_LIST_LOCK();
LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink);
UNP_REF_LIST_UNLOCK();
soisconnected(so);
break;
case SOCK_STREAM:
case SOCK_SEQPACKET:
KASSERT(unp2->unp_conn == NULL,
("%s: socket %p is already connected", __func__, unp2));
unp2->unp_conn = unp;
soisconnected(so);
soisconnected(so2);
break;
default:
panic("unp_connect2");
}
}
static void
unp_disconnect(struct unpcb *unp, struct unpcb *unp2)
{
struct socket *so, *so2;
struct mbuf *m = NULL;
#ifdef INVARIANTS
struct unpcb *unptmp;
#endif
UNP_PCB_LOCK_ASSERT(unp);
UNP_PCB_LOCK_ASSERT(unp2);
KASSERT(unp->unp_conn == unp2,
("%s: unpcb %p is not connected to %p", __func__, unp, unp2));
unp->unp_conn = NULL;
so = unp->unp_socket;
so2 = unp2->unp_socket;
switch (unp->unp_socket->so_type) {
case SOCK_DGRAM:
/*
* Remove our send socket buffer from the peer's receive buffer.
* Move the data to the receive buffer only if it is empty.
* This is a protection against a scenario where a peer
* connects, floods and disconnects, effectively blocking
* sendto() from unconnected sockets.
*/
SOCK_RECVBUF_LOCK(so2);
if (!STAILQ_EMPTY(&so->so_snd.uxdg_mb)) {
TAILQ_REMOVE(&so2->so_rcv.uxdg_conns, &so->so_snd,
uxdg_clist);
if (__predict_true((so2->so_rcv.sb_state &
SBS_CANTRCVMORE) == 0) &&
STAILQ_EMPTY(&so2->so_rcv.uxdg_mb)) {
STAILQ_CONCAT(&so2->so_rcv.uxdg_mb,
&so->so_snd.uxdg_mb);
so2->so_rcv.uxdg_cc += so->so_snd.uxdg_cc;
so2->so_rcv.uxdg_ctl += so->so_snd.uxdg_ctl;
so2->so_rcv.uxdg_mbcnt += so->so_snd.uxdg_mbcnt;
} else {
m = STAILQ_FIRST(&so->so_snd.uxdg_mb);
STAILQ_INIT(&so->so_snd.uxdg_mb);
so2->so_rcv.sb_acc -= so->so_snd.uxdg_cc;
so2->so_rcv.sb_ccc -= so->so_snd.uxdg_cc;
so2->so_rcv.sb_ctl -= so->so_snd.uxdg_ctl;
so2->so_rcv.sb_mbcnt -= so->so_snd.uxdg_mbcnt;
}
/* Note: so may reconnect. */
so->so_snd.uxdg_cc = 0;
so->so_snd.uxdg_ctl = 0;
so->so_snd.uxdg_mbcnt = 0;
}
SOCK_RECVBUF_UNLOCK(so2);
UNP_REF_LIST_LOCK();
#ifdef INVARIANTS
LIST_FOREACH(unptmp, &unp2->unp_refs, unp_reflink) {
if (unptmp == unp)
break;
}
KASSERT(unptmp != NULL,
("%s: %p not found in reflist of %p", __func__, unp, unp2));
#endif
LIST_REMOVE(unp, unp_reflink);
UNP_REF_LIST_UNLOCK();
if (so) {
SOCK_LOCK(so);
so->so_state &= ~SS_ISCONNECTED;
SOCK_UNLOCK(so);
}
break;
case SOCK_STREAM:
case SOCK_SEQPACKET:
if (so)
soisdisconnected(so);
MPASS(unp2->unp_conn == unp);
unp2->unp_conn = NULL;
if (so2)
soisdisconnected(so2);
break;
}
if (unp == unp2) {
unp_pcb_rele_notlast(unp);
if (!unp_pcb_rele(unp))
UNP_PCB_UNLOCK(unp);
} else {
if (!unp_pcb_rele(unp))
UNP_PCB_UNLOCK(unp);
if (!unp_pcb_rele(unp2))
UNP_PCB_UNLOCK(unp2);
}
if (m != NULL) {
unp_scan(m, unp_freerights);
m_freem(m);
}
}
/*
* unp_pcblist() walks the global list of struct unpcb's to generate a
* pointer list, bumping the refcount on each unpcb. It then copies them out
* sequentially, validating the generation number on each to see if it has
* been detached. All of this is necessary because copyout() may sleep on
* disk I/O.
*/
static int
unp_pcblist(SYSCTL_HANDLER_ARGS)
{
struct unpcb *unp, **unp_list;
unp_gen_t gencnt;
struct xunpgen *xug;
struct unp_head *head;
struct xunpcb *xu;
u_int i;
int error, n;
switch ((intptr_t)arg1) {
case SOCK_STREAM:
head = &unp_shead;
break;
case SOCK_DGRAM:
head = &unp_dhead;
break;
case SOCK_SEQPACKET:
head = &unp_sphead;
break;
default:
panic("unp_pcblist: arg1 %d", (int)(intptr_t)arg1);
}
/*
* The process of preparing the PCB list is too time-consuming and
* resource-intensive to repeat twice on every request.
*/
if (req->oldptr == NULL) {
n = unp_count;
req->oldidx = 2 * (sizeof *xug)
+ (n + n/8) * sizeof(struct xunpcb);
return (0);
}
if (req->newptr != NULL)
return (EPERM);
/*
* OK, now we're committed to doing something.
*/
xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK | M_ZERO);
UNP_LINK_RLOCK();
gencnt = unp_gencnt;
n = unp_count;
UNP_LINK_RUNLOCK();
xug->xug_len = sizeof *xug;
xug->xug_count = n;
xug->xug_gen = gencnt;
xug->xug_sogen = so_gencnt;
error = SYSCTL_OUT(req, xug, sizeof *xug);
if (error) {
free(xug, M_TEMP);
return (error);
}
unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK);
UNP_LINK_RLOCK();
for (unp = LIST_FIRST(head), i = 0; unp && i < n;
unp = LIST_NEXT(unp, unp_link)) {
UNP_PCB_LOCK(unp);
if (unp->unp_gencnt <= gencnt) {
if (cr_cansee(req->td->td_ucred,
unp->unp_socket->so_cred)) {
UNP_PCB_UNLOCK(unp);
continue;
}
unp_list[i++] = unp;
unp_pcb_hold(unp);
}
UNP_PCB_UNLOCK(unp);
}
UNP_LINK_RUNLOCK();
n = i; /* In case we lost some during malloc. */
error = 0;
xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK | M_ZERO);
for (i = 0; i < n; i++) {
unp = unp_list[i];
UNP_PCB_LOCK(unp);
if (unp_pcb_rele(unp))
continue;
if (unp->unp_gencnt <= gencnt) {
xu->xu_len = sizeof *xu;
xu->xu_unpp = (uintptr_t)unp;
/*
* XXX - need more locking here to protect against
* connect/disconnect races for SMP.
*/
if (unp->unp_addr != NULL)
bcopy(unp->unp_addr, &xu->xu_addr,
unp->unp_addr->sun_len);
else
bzero(&xu->xu_addr, sizeof(xu->xu_addr));
if (unp->unp_conn != NULL &&
unp->unp_conn->unp_addr != NULL)
bcopy(unp->unp_conn->unp_addr,
&xu->xu_caddr,
unp->unp_conn->unp_addr->sun_len);
else
bzero(&xu->xu_caddr, sizeof(xu->xu_caddr));
xu->unp_vnode = (uintptr_t)unp->unp_vnode;
xu->unp_conn = (uintptr_t)unp->unp_conn;
xu->xu_firstref = (uintptr_t)LIST_FIRST(&unp->unp_refs);
xu->xu_nextref = (uintptr_t)LIST_NEXT(unp, unp_reflink);
xu->unp_gencnt = unp->unp_gencnt;
sotoxsocket(unp->unp_socket, &xu->xu_socket);
UNP_PCB_UNLOCK(unp);
error = SYSCTL_OUT(req, xu, sizeof *xu);
} else {
UNP_PCB_UNLOCK(unp);
}
}
free(xu, M_TEMP);
if (!error) {
/*
* Give the user an updated idea of our state. If the
* generation differs from what we told her before, she knows
* that something happened while we were processing this
* request, and it might be necessary to retry.
*/
xug->xug_gen = unp_gencnt;
xug->xug_sogen = so_gencnt;
xug->xug_count = unp_count;
error = SYSCTL_OUT(req, xug, sizeof *xug);
}
free(unp_list, M_TEMP);
free(xug, M_TEMP);
return (error);
}
SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist,
CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE,
(void *)(intptr_t)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb",
"List of active local datagram sockets");
SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist,
CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE,
(void *)(intptr_t)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb",
"List of active local stream sockets");
SYSCTL_PROC(_net_local_seqpacket, OID_AUTO, pcblist,
CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE,
(void *)(intptr_t)SOCK_SEQPACKET, 0, unp_pcblist, "S,xunpcb",
"List of active local seqpacket sockets");
static void
unp_shutdown(struct unpcb *unp)
{
struct unpcb *unp2;
struct socket *so;
UNP_PCB_LOCK_ASSERT(unp);
unp2 = unp->unp_conn;
if ((unp->unp_socket->so_type == SOCK_STREAM ||
(unp->unp_socket->so_type == SOCK_SEQPACKET)) && unp2 != NULL) {
so = unp2->unp_socket;
if (so != NULL)
socantrcvmore(so);
}
}
static void
unp_drop(struct unpcb *unp)
{
struct socket *so;
struct unpcb *unp2;
/*
* Regardless of whether the socket's peer dropped the connection
* with this socket by aborting or disconnecting, POSIX requires
* that ECONNRESET is returned.
*/
UNP_PCB_LOCK(unp);
so = unp->unp_socket;
if (so)
so->so_error = ECONNRESET;
if ((unp2 = unp_pcb_lock_peer(unp)) != NULL) {
/* Last reference dropped in unp_disconnect(). */
unp_pcb_rele_notlast(unp);
unp_disconnect(unp, unp2);
} else if (!unp_pcb_rele(unp)) {
UNP_PCB_UNLOCK(unp);
}
}
static void
unp_freerights(struct filedescent **fdep, int fdcount)
{
struct file *fp;
int i;
KASSERT(fdcount > 0, ("%s: fdcount %d", __func__, fdcount));
for (i = 0; i < fdcount; i++) {
fp = fdep[i]->fde_file;
filecaps_free(&fdep[i]->fde_caps);
unp_discard(fp);
}
free(fdep[0], M_FILECAPS);
}
static int
unp_externalize(struct mbuf *control, struct mbuf **controlp, int flags)
{
struct thread *td = curthread; /* XXX */
struct cmsghdr *cm = mtod(control, struct cmsghdr *);
int i;
int *fdp;
struct filedesc *fdesc = td->td_proc->p_fd;
struct filedescent **fdep;
void *data;
socklen_t clen = control->m_len, datalen;
int error, newfds;
u_int newlen;
UNP_LINK_UNLOCK_ASSERT();
error = 0;
if (controlp != NULL) /* controlp == NULL => free control messages */
*controlp = NULL;
while (cm != NULL) {
MPASS(clen >= sizeof(*cm) && clen >= cm->cmsg_len);
data = CMSG_DATA(cm);
datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
if (cm->cmsg_level == SOL_SOCKET
&& cm->cmsg_type == SCM_RIGHTS) {
newfds = datalen / sizeof(*fdep);
if (newfds == 0)
goto next;
fdep = data;
/* If we're not outputting the descriptors free them. */
if (error || controlp == NULL) {
unp_freerights(fdep, newfds);
goto next;
}
FILEDESC_XLOCK(fdesc);
/*
* Now change each pointer to an fd in the global
* table to an integer that is the index to the local
* fd table entry that we set up to point to the
* global one we are transferring.
*/
newlen = newfds * sizeof(int);
*controlp = sbcreatecontrol(NULL, newlen,
SCM_RIGHTS, SOL_SOCKET, M_WAITOK);
fdp = (int *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
if ((error = fdallocn(td, 0, fdp, newfds))) {
FILEDESC_XUNLOCK(fdesc);
unp_freerights(fdep, newfds);
m_freem(*controlp);
*controlp = NULL;
goto next;
}
for (i = 0; i < newfds; i++, fdp++) {
_finstall(fdesc, fdep[i]->fde_file, *fdp,
(flags & MSG_CMSG_CLOEXEC) != 0 ? O_CLOEXEC : 0,
&fdep[i]->fde_caps);
unp_externalize_fp(fdep[i]->fde_file);
}
/*
* The new type indicates that the mbuf data refers to
* kernel resources that may need to be released before
* the mbuf is freed.
*/
m_chtype(*controlp, MT_EXTCONTROL);
FILEDESC_XUNLOCK(fdesc);
free(fdep[0], M_FILECAPS);
} else {
/* We can just copy anything else across. */
if (error || controlp == NULL)
goto next;
*controlp = sbcreatecontrol(NULL, datalen,
cm->cmsg_type, cm->cmsg_level, M_WAITOK);
bcopy(data,
CMSG_DATA(mtod(*controlp, struct cmsghdr *)),
datalen);
}
controlp = &(*controlp)->m_next;
next:
if (CMSG_SPACE(datalen) < clen) {
clen -= CMSG_SPACE(datalen);
cm = (struct cmsghdr *)
((caddr_t)cm + CMSG_SPACE(datalen));
} else {
clen = 0;
cm = NULL;
}
}
m_freem(control);
return (error);
}
static void
unp_zone_change(void *tag)
{
uma_zone_set_max(unp_zone, maxsockets);
}
#ifdef INVARIANTS
static void
unp_zdtor(void *mem, int size __unused, void *arg __unused)
{
struct unpcb *unp;
unp = mem;
KASSERT(LIST_EMPTY(&unp->unp_refs),
("%s: unpcb %p has lingering refs", __func__, unp));
KASSERT(unp->unp_socket == NULL,
("%s: unpcb %p has socket backpointer", __func__, unp));
KASSERT(unp->unp_vnode == NULL,
("%s: unpcb %p has vnode references", __func__, unp));
KASSERT(unp->unp_conn == NULL,
("%s: unpcb %p is still connected", __func__, unp));
KASSERT(unp->unp_addr == NULL,
("%s: unpcb %p has leaked addr", __func__, unp));
}
#endif
static void
unp_init(void *arg __unused)
{
uma_dtor dtor;
#ifdef INVARIANTS
dtor = unp_zdtor;
#else
dtor = NULL;
#endif
unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, dtor,
NULL, NULL, UMA_ALIGN_CACHE, 0);
uma_zone_set_max(unp_zone, maxsockets);
uma_zone_set_warning(unp_zone, "kern.ipc.maxsockets limit reached");
EVENTHANDLER_REGISTER(maxsockets_change, unp_zone_change,
NULL, EVENTHANDLER_PRI_ANY);
LIST_INIT(&unp_dhead);
LIST_INIT(&unp_shead);
LIST_INIT(&unp_sphead);
SLIST_INIT(&unp_defers);
TIMEOUT_TASK_INIT(taskqueue_thread, &unp_gc_task, 0, unp_gc, NULL);
TASK_INIT(&unp_defer_task, 0, unp_process_defers, NULL);
UNP_LINK_LOCK_INIT();
UNP_DEFERRED_LOCK_INIT();
}
SYSINIT(unp_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_SECOND, unp_init, NULL);
static void
unp_internalize_cleanup_rights(struct mbuf *control)
{
struct cmsghdr *cp;
struct mbuf *m;
void *data;
socklen_t datalen;
for (m = control; m != NULL; m = m->m_next) {
cp = mtod(m, struct cmsghdr *);
if (cp->cmsg_level != SOL_SOCKET ||
cp->cmsg_type != SCM_RIGHTS)
continue;
data = CMSG_DATA(cp);
datalen = (caddr_t)cp + cp->cmsg_len - (caddr_t)data;
unp_freerights(data, datalen / sizeof(struct filedesc *));
}
}
static int
unp_internalize(struct mbuf **controlp, struct thread *td,
struct mbuf **clast, u_int *space, u_int *mbcnt)
{
struct mbuf *control, **initial_controlp;
struct proc *p;
struct filedesc *fdesc;
struct bintime *bt;
struct cmsghdr *cm;
struct cmsgcred *cmcred;
struct filedescent *fde, **fdep, *fdev;
struct file *fp;
struct timeval *tv;
struct timespec *ts;
void *data;
socklen_t clen, datalen;
int i, j, error, *fdp, oldfds;
u_int newlen;
MPASS((*controlp)->m_next == NULL); /* COMPAT_OLDSOCK may violate */
UNP_LINK_UNLOCK_ASSERT();
p = td->td_proc;
fdesc = p->p_fd;
error = 0;
control = *controlp;
*controlp = NULL;
initial_controlp = controlp;
for (clen = control->m_len, cm = mtod(control, struct cmsghdr *),
data = CMSG_DATA(cm);
clen >= sizeof(*cm) && cm->cmsg_level == SOL_SOCKET &&
clen >= cm->cmsg_len && cm->cmsg_len >= sizeof(*cm) &&
(char *)cm + cm->cmsg_len >= (char *)data;
clen -= min(CMSG_SPACE(datalen), clen),
cm = (struct cmsghdr *) ((char *)cm + CMSG_SPACE(datalen)),
data = CMSG_DATA(cm)) {
datalen = (char *)cm + cm->cmsg_len - (char *)data;
switch (cm->cmsg_type) {
case SCM_CREDS:
*controlp = sbcreatecontrol(NULL, sizeof(*cmcred),
SCM_CREDS, SOL_SOCKET, M_WAITOK);
cmcred = (struct cmsgcred *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
cmcred->cmcred_pid = p->p_pid;
cmcred->cmcred_uid = td->td_ucred->cr_ruid;
cmcred->cmcred_gid = td->td_ucred->cr_rgid;
cmcred->cmcred_euid = td->td_ucred->cr_uid;
cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups,
CMGROUP_MAX);
for (i = 0; i < cmcred->cmcred_ngroups; i++)
cmcred->cmcred_groups[i] =
td->td_ucred->cr_groups[i];
break;
case SCM_RIGHTS:
oldfds = datalen / sizeof (int);
if (oldfds == 0)
continue;
/* On some machines sizeof pointer is bigger than
* sizeof int, so we need to check if data fits into
* single mbuf. We could allocate several mbufs, and
* unp_externalize() should even properly handle that.
* But it is not worth to complicate the code for an
* insane scenario of passing over 200 file descriptors
* at once.
*/
newlen = oldfds * sizeof(fdep[0]);
if (CMSG_SPACE(newlen) > MCLBYTES) {
error = EMSGSIZE;
goto out;
}
/*
* Check that all the FDs passed in refer to legal
* files. If not, reject the entire operation.
*/
fdp = data;
FILEDESC_SLOCK(fdesc);
for (i = 0; i < oldfds; i++, fdp++) {
fp = fget_noref(fdesc, *fdp);
if (fp == NULL) {
FILEDESC_SUNLOCK(fdesc);
error = EBADF;
goto out;
}
if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) {
FILEDESC_SUNLOCK(fdesc);
error = EOPNOTSUPP;
goto out;
}
}
/*
* Now replace the integer FDs with pointers to the
* file structure and capability rights.
*/
*controlp = sbcreatecontrol(NULL, newlen,
SCM_RIGHTS, SOL_SOCKET, M_WAITOK);
fdp = data;
for (i = 0; i < oldfds; i++, fdp++) {
if (!fhold(fdesc->fd_ofiles[*fdp].fde_file)) {
fdp = data;
for (j = 0; j < i; j++, fdp++) {
fdrop(fdesc->fd_ofiles[*fdp].
fde_file, td);
}
FILEDESC_SUNLOCK(fdesc);
error = EBADF;
goto out;
}
}
fdp = data;
fdep = (struct filedescent **)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
fdev = malloc(sizeof(*fdev) * oldfds, M_FILECAPS,
M_WAITOK);
for (i = 0; i < oldfds; i++, fdev++, fdp++) {
fde = &fdesc->fd_ofiles[*fdp];
fdep[i] = fdev;
fdep[i]->fde_file = fde->fde_file;
filecaps_copy(&fde->fde_caps,
&fdep[i]->fde_caps, true);
unp_internalize_fp(fdep[i]->fde_file);
}
FILEDESC_SUNLOCK(fdesc);
break;
case SCM_TIMESTAMP:
*controlp = sbcreatecontrol(NULL, sizeof(*tv),
SCM_TIMESTAMP, SOL_SOCKET, M_WAITOK);
tv = (struct timeval *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
microtime(tv);
break;
case SCM_BINTIME:
*controlp = sbcreatecontrol(NULL, sizeof(*bt),
SCM_BINTIME, SOL_SOCKET, M_WAITOK);
bt = (struct bintime *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
bintime(bt);
break;
case SCM_REALTIME:
*controlp = sbcreatecontrol(NULL, sizeof(*ts),
SCM_REALTIME, SOL_SOCKET, M_WAITOK);
ts = (struct timespec *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
nanotime(ts);
break;
case SCM_MONOTONIC:
*controlp = sbcreatecontrol(NULL, sizeof(*ts),
SCM_MONOTONIC, SOL_SOCKET, M_WAITOK);
ts = (struct timespec *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
nanouptime(ts);
break;
default:
error = EINVAL;
goto out;
}
if (space != NULL) {
*space += (*controlp)->m_len;
*mbcnt += MSIZE;
if ((*controlp)->m_flags & M_EXT)
*mbcnt += (*controlp)->m_ext.ext_size;
*clast = *controlp;
}
controlp = &(*controlp)->m_next;
}
if (clen > 0)
error = EINVAL;
out:
if (error != 0 && initial_controlp != NULL)
unp_internalize_cleanup_rights(*initial_controlp);
m_freem(control);
return (error);
}
static struct mbuf *
unp_addsockcred(struct thread *td, struct mbuf *control, int mode,
struct mbuf **clast, u_int *space, u_int *mbcnt)
{
struct mbuf *m, *n, *n_prev;
const struct cmsghdr *cm;
int ngroups, i, cmsgtype;
size_t ctrlsz;
ngroups = MIN(td->td_ucred->cr_ngroups, CMGROUP_MAX);
if (mode & UNP_WANTCRED_ALWAYS) {
ctrlsz = SOCKCRED2SIZE(ngroups);
cmsgtype = SCM_CREDS2;
} else {
ctrlsz = SOCKCREDSIZE(ngroups);
cmsgtype = SCM_CREDS;
}
m = sbcreatecontrol(NULL, ctrlsz, cmsgtype, SOL_SOCKET, M_NOWAIT);
if (m == NULL)
return (control);
MPASS((m->m_flags & M_EXT) == 0 && m->m_next == NULL);
if (mode & UNP_WANTCRED_ALWAYS) {
struct sockcred2 *sc;
sc = (void *)CMSG_DATA(mtod(m, struct cmsghdr *));
sc->sc_version = 0;
sc->sc_pid = td->td_proc->p_pid;
sc->sc_uid = td->td_ucred->cr_ruid;
sc->sc_euid = td->td_ucred->cr_uid;
sc->sc_gid = td->td_ucred->cr_rgid;
sc->sc_egid = td->td_ucred->cr_gid;
sc->sc_ngroups = ngroups;
for (i = 0; i < sc->sc_ngroups; i++)
sc->sc_groups[i] = td->td_ucred->cr_groups[i];
} else {
struct sockcred *sc;
sc = (void *)CMSG_DATA(mtod(m, struct cmsghdr *));
sc->sc_uid = td->td_ucred->cr_ruid;
sc->sc_euid = td->td_ucred->cr_uid;
sc->sc_gid = td->td_ucred->cr_rgid;
sc->sc_egid = td->td_ucred->cr_gid;
sc->sc_ngroups = ngroups;
for (i = 0; i < sc->sc_ngroups; i++)
sc->sc_groups[i] = td->td_ucred->cr_groups[i];
}
/*
* Unlink SCM_CREDS control messages (struct cmsgcred), since just
* created SCM_CREDS control message (struct sockcred) has another
* format.
*/
if (control != NULL && cmsgtype == SCM_CREDS)
for (n = control, n_prev = NULL; n != NULL;) {
cm = mtod(n, struct cmsghdr *);
if (cm->cmsg_level == SOL_SOCKET &&
cm->cmsg_type == SCM_CREDS) {
if (n_prev == NULL)
control = n->m_next;
else
n_prev->m_next = n->m_next;
if (space != NULL) {
MPASS(*space >= n->m_len);
*space -= n->m_len;
MPASS(*mbcnt >= MSIZE);
*mbcnt -= MSIZE;
if (n->m_flags & M_EXT) {
MPASS(*mbcnt >=
n->m_ext.ext_size);
*mbcnt -= n->m_ext.ext_size;
}
MPASS(clast);
if (*clast == n) {
MPASS(n->m_next == NULL);
if (n_prev == NULL)
*clast = m;
else
*clast = n_prev;
}
}
n = m_free(n);
} else {
n_prev = n;
n = n->m_next;
}
}
/* Prepend it to the head. */
m->m_next = control;
if (space != NULL) {
*space += m->m_len;
*mbcnt += MSIZE;
if (control == NULL)
*clast = m;
}
return (m);
}
static struct unpcb *
fptounp(struct file *fp)
{
struct socket *so;
if (fp->f_type != DTYPE_SOCKET)
return (NULL);
if ((so = fp->f_data) == NULL)
return (NULL);
if (so->so_proto->pr_domain != &localdomain)
return (NULL);
return sotounpcb(so);
}
static void
unp_discard(struct file *fp)
{
struct unp_defer *dr;
if (unp_externalize_fp(fp)) {
dr = malloc(sizeof(*dr), M_TEMP, M_WAITOK);
dr->ud_fp = fp;
UNP_DEFERRED_LOCK();
SLIST_INSERT_HEAD(&unp_defers, dr, ud_link);
UNP_DEFERRED_UNLOCK();
atomic_add_int(&unp_defers_count, 1);
taskqueue_enqueue(taskqueue_thread, &unp_defer_task);
} else
closef_nothread(fp);
}
static void
unp_process_defers(void *arg __unused, int pending)
{
struct unp_defer *dr;
SLIST_HEAD(, unp_defer) drl;
int count;
SLIST_INIT(&drl);
for (;;) {
UNP_DEFERRED_LOCK();
if (SLIST_FIRST(&unp_defers) == NULL) {
UNP_DEFERRED_UNLOCK();
break;
}
SLIST_SWAP(&unp_defers, &drl, unp_defer);
UNP_DEFERRED_UNLOCK();
count = 0;
while ((dr = SLIST_FIRST(&drl)) != NULL) {
SLIST_REMOVE_HEAD(&drl, ud_link);
closef_nothread(dr->ud_fp);
free(dr, M_TEMP);
count++;
}
atomic_add_int(&unp_defers_count, -count);
}
}
static void
unp_internalize_fp(struct file *fp)
{
struct unpcb *unp;
UNP_LINK_WLOCK();
if ((unp = fptounp(fp)) != NULL) {
unp->unp_file = fp;
unp->unp_msgcount++;
}
unp_rights++;
UNP_LINK_WUNLOCK();
}
static int
unp_externalize_fp(struct file *fp)
{
struct unpcb *unp;
int ret;
UNP_LINK_WLOCK();
if ((unp = fptounp(fp)) != NULL) {
unp->unp_msgcount--;
ret = 1;
} else
ret = 0;
unp_rights--;
UNP_LINK_WUNLOCK();
return (ret);
}
/*
* unp_defer indicates whether additional work has been defered for a future
* pass through unp_gc(). It is thread local and does not require explicit
* synchronization.
*/
static int unp_marked;
static void
unp_remove_dead_ref(struct filedescent **fdep, int fdcount)
{
struct unpcb *unp;
struct file *fp;
int i;
/*
* This function can only be called from the gc task.
*/
KASSERT(taskqueue_member(taskqueue_thread, curthread) != 0,
("%s: not on gc callout", __func__));
UNP_LINK_LOCK_ASSERT();
for (i = 0; i < fdcount; i++) {
fp = fdep[i]->fde_file;
if ((unp = fptounp(fp)) == NULL)
continue;
if ((unp->unp_gcflag & UNPGC_DEAD) == 0)
continue;
unp->unp_gcrefs--;
}
}
static void
unp_restore_undead_ref(struct filedescent **fdep, int fdcount)
{
struct unpcb *unp;
struct file *fp;
int i;
/*
* This function can only be called from the gc task.
*/
KASSERT(taskqueue_member(taskqueue_thread, curthread) != 0,
("%s: not on gc callout", __func__));
UNP_LINK_LOCK_ASSERT();
for (i = 0; i < fdcount; i++) {
fp = fdep[i]->fde_file;
if ((unp = fptounp(fp)) == NULL)
continue;
if ((unp->unp_gcflag & UNPGC_DEAD) == 0)
continue;
unp->unp_gcrefs++;
unp_marked++;
}
}
static void
unp_scan_socket(struct socket *so, void (*op)(struct filedescent **, int))
{
struct sockbuf *sb;
SOCK_LOCK_ASSERT(so);
if (sotounpcb(so)->unp_gcflag & UNPGC_IGNORE_RIGHTS)
return;
SOCK_RECVBUF_LOCK(so);
switch (so->so_type) {
case SOCK_DGRAM:
unp_scan(STAILQ_FIRST(&so->so_rcv.uxdg_mb), op);
unp_scan(so->so_rcv.uxdg_peeked, op);
TAILQ_FOREACH(sb, &so->so_rcv.uxdg_conns, uxdg_clist)
unp_scan(STAILQ_FIRST(&sb->uxdg_mb), op);
break;
case SOCK_STREAM:
case SOCK_SEQPACKET:
unp_scan(so->so_rcv.sb_mb, op);
break;
}
SOCK_RECVBUF_UNLOCK(so);
}
static void
unp_gc_scan(struct unpcb *unp, void (*op)(struct filedescent **, int))
{
struct socket *so, *soa;
so = unp->unp_socket;
SOCK_LOCK(so);
if (SOLISTENING(so)) {
/*
* Mark all sockets in our accept queue.
*/
TAILQ_FOREACH(soa, &so->sol_comp, so_list)
unp_scan_socket(soa, op);
} else {
/*
* Mark all sockets we reference with RIGHTS.
*/
unp_scan_socket(so, op);
}
SOCK_UNLOCK(so);
}
static int unp_recycled;
SYSCTL_INT(_net_local, OID_AUTO, recycled, CTLFLAG_RD, &unp_recycled, 0,
"Number of unreachable sockets claimed by the garbage collector.");
static int unp_taskcount;
SYSCTL_INT(_net_local, OID_AUTO, taskcount, CTLFLAG_RD, &unp_taskcount, 0,
"Number of times the garbage collector has run.");
SYSCTL_UINT(_net_local, OID_AUTO, sockcount, CTLFLAG_RD, &unp_count, 0,
"Number of active local sockets.");
static void
unp_gc(__unused void *arg, int pending)
{
struct unp_head *heads[] = { &unp_dhead, &unp_shead, &unp_sphead,
NULL };
struct unp_head **head;
struct unp_head unp_deadhead; /* List of potentially-dead sockets. */
struct file *f, **unref;
struct unpcb *unp, *unptmp;
int i, total, unp_unreachable;
LIST_INIT(&unp_deadhead);
unp_taskcount++;
UNP_LINK_RLOCK();
/*
* First determine which sockets may be in cycles.
*/
unp_unreachable = 0;
for (head = heads; *head != NULL; head++)
LIST_FOREACH(unp, *head, unp_link) {
KASSERT((unp->unp_gcflag & ~UNPGC_IGNORE_RIGHTS) == 0,
("%s: unp %p has unexpected gc flags 0x%x",
__func__, unp, (unsigned int)unp->unp_gcflag));
f = unp->unp_file;
/*
* Check for an unreachable socket potentially in a
* cycle. It must be in a queue as indicated by
* msgcount, and this must equal the file reference
* count. Note that when msgcount is 0 the file is
* NULL.
*/
if (f != NULL && unp->unp_msgcount != 0 &&
refcount_load(&f->f_count) == unp->unp_msgcount) {
LIST_INSERT_HEAD(&unp_deadhead, unp, unp_dead);
unp->unp_gcflag |= UNPGC_DEAD;
unp->unp_gcrefs = unp->unp_msgcount;
unp_unreachable++;
}
}
/*
* Scan all sockets previously marked as potentially being in a cycle
* and remove the references each socket holds on any UNPGC_DEAD
* sockets in its queue. After this step, all remaining references on
* sockets marked UNPGC_DEAD should not be part of any cycle.
*/
LIST_FOREACH(unp, &unp_deadhead, unp_dead)
unp_gc_scan(unp, unp_remove_dead_ref);
/*
* If a socket still has a non-negative refcount, it cannot be in a
* cycle. In this case increment refcount of all children iteratively.
* Stop the scan once we do a complete loop without discovering
* a new reachable socket.
*/
do {
unp_marked = 0;
LIST_FOREACH_SAFE(unp, &unp_deadhead, unp_dead, unptmp)
if (unp->unp_gcrefs > 0) {
unp->unp_gcflag &= ~UNPGC_DEAD;
LIST_REMOVE(unp, unp_dead);
KASSERT(unp_unreachable > 0,
("%s: unp_unreachable underflow.",
__func__));
unp_unreachable--;
unp_gc_scan(unp, unp_restore_undead_ref);
}
} while (unp_marked);
UNP_LINK_RUNLOCK();
if (unp_unreachable == 0)
return;
/*
* Allocate space for a local array of dead unpcbs.
* TODO: can this path be simplified by instead using the local
* dead list at unp_deadhead, after taking out references
* on the file object and/or unpcb and dropping the link lock?
*/
unref = malloc(unp_unreachable * sizeof(struct file *),
M_TEMP, M_WAITOK);
/*
* Iterate looking for sockets which have been specifically marked
* as unreachable and store them locally.
*/
UNP_LINK_RLOCK();
total = 0;
LIST_FOREACH(unp, &unp_deadhead, unp_dead) {
KASSERT((unp->unp_gcflag & UNPGC_DEAD) != 0,
("%s: unp %p not marked UNPGC_DEAD", __func__, unp));
unp->unp_gcflag &= ~UNPGC_DEAD;
f = unp->unp_file;
if (unp->unp_msgcount == 0 || f == NULL ||
refcount_load(&f->f_count) != unp->unp_msgcount ||
!fhold(f))
continue;
unref[total++] = f;
KASSERT(total <= unp_unreachable,
("%s: incorrect unreachable count.", __func__));
}
UNP_LINK_RUNLOCK();
/*
* Now flush all sockets, free'ing rights. This will free the
* struct files associated with these sockets but leave each socket
* with one remaining ref.
*/
for (i = 0; i < total; i++) {
struct socket *so;
so = unref[i]->f_data;
CURVNET_SET(so->so_vnet);
socantrcvmore(so);
unp_dispose(so);
CURVNET_RESTORE();
}
/*
* And finally release the sockets so they can be reclaimed.
*/
for (i = 0; i < total; i++)
fdrop(unref[i], NULL);
unp_recycled += total;
free(unref, M_TEMP);
}
/*
* Synchronize against unp_gc, which can trip over data as we are freeing it.
*/
static void
unp_dispose(struct socket *so)
{
struct sockbuf *sb;
struct unpcb *unp;
struct mbuf *m;
int error __diagused;
MPASS(!SOLISTENING(so));
unp = sotounpcb(so);
UNP_LINK_WLOCK();
unp->unp_gcflag |= UNPGC_IGNORE_RIGHTS;
UNP_LINK_WUNLOCK();
/*
* Grab our special mbufs before calling sbrelease().
*/
error = SOCK_IO_RECV_LOCK(so, SBL_WAIT | SBL_NOINTR);
MPASS(!error);
SOCK_RECVBUF_LOCK(so);
switch (so->so_type) {
case SOCK_DGRAM:
while ((sb = TAILQ_FIRST(&so->so_rcv.uxdg_conns)) != NULL) {
STAILQ_CONCAT(&so->so_rcv.uxdg_mb, &sb->uxdg_mb);
TAILQ_REMOVE(&so->so_rcv.uxdg_conns, sb, uxdg_clist);
/* Note: socket of sb may reconnect. */
sb->uxdg_cc = sb->uxdg_ctl = sb->uxdg_mbcnt = 0;
}
sb = &so->so_rcv;
if (sb->uxdg_peeked != NULL) {
STAILQ_INSERT_HEAD(&sb->uxdg_mb, sb->uxdg_peeked,
m_stailqpkt);
sb->uxdg_peeked = NULL;
}
m = STAILQ_FIRST(&sb->uxdg_mb);
STAILQ_INIT(&sb->uxdg_mb);
/* XXX: our shortened sbrelease() */
(void)chgsbsize(so->so_cred->cr_uidinfo, &sb->sb_hiwat, 0,
RLIM_INFINITY);
/*
* XXXGL Mark sb with SBS_CANTRCVMORE. This is needed to
* prevent uipc_sosend_dgram() or unp_disconnect() adding more
* data to the socket.
* We came here either through shutdown(2) or from the final
* sofree(). The sofree() case is simple as it guarantees
* that no more sends will happen, however we can race with
* unp_disconnect() from our peer. The shutdown(2) case is
* more exotic. It would call into unp_dispose() only if
* socket is SS_ISCONNECTED. This is possible if we did
* connect(2) on this socket and we also had it bound with
* bind(2) and receive connections from other sockets.
* Because uipc_shutdown() violates POSIX (see comment
* there) we will end up here shutting down our receive side.
* Of course this will have affect not only on the peer we
* connect(2)ed to, but also on all of the peers who had
* connect(2)ed to us. Their sends would end up with ENOBUFS.
*/
sb->sb_state |= SBS_CANTRCVMORE;
break;
case SOCK_STREAM:
case SOCK_SEQPACKET:
sb = &so->so_rcv;
m = sbcut_locked(sb, sb->sb_ccc);
KASSERT(sb->sb_ccc == 0 && sb->sb_mb == 0 && sb->sb_mbcnt == 0,
("%s: ccc %u mb %p mbcnt %u", __func__,
sb->sb_ccc, (void *)sb->sb_mb, sb->sb_mbcnt));
sbrelease_locked(so, SO_RCV);
break;
}
SOCK_RECVBUF_UNLOCK(so);
SOCK_IO_RECV_UNLOCK(so);
if (m != NULL) {
unp_scan(m, unp_freerights);
m_freem(m);
}
}
static void
unp_scan(struct mbuf *m0, void (*op)(struct filedescent **, int))
{
struct mbuf *m;
struct cmsghdr *cm;
void *data;
socklen_t clen, datalen;
while (m0 != NULL) {
for (m = m0; m; m = m->m_next) {
if (m->m_type != MT_CONTROL)
continue;
cm = mtod(m, struct cmsghdr *);
clen = m->m_len;
while (cm != NULL) {
if (sizeof(*cm) > clen || cm->cmsg_len > clen)
break;
data = CMSG_DATA(cm);
datalen = (caddr_t)cm + cm->cmsg_len
- (caddr_t)data;
if (cm->cmsg_level == SOL_SOCKET &&
cm->cmsg_type == SCM_RIGHTS) {
(*op)(data, datalen /
sizeof(struct filedescent *));
}
if (CMSG_SPACE(datalen) < clen) {
clen -= CMSG_SPACE(datalen);
cm = (struct cmsghdr *)
((caddr_t)cm + CMSG_SPACE(datalen));
} else {
clen = 0;
cm = NULL;
}
}
}
m0 = m0->m_nextpkt;
}
}
/*
* Definitions of protocols supported in the LOCAL domain.
*/
static struct protosw streamproto = {
.pr_type = SOCK_STREAM,
.pr_flags = PR_CONNREQUIRED | PR_WANTRCVD | PR_CAPATTACH,
.pr_ctloutput = &uipc_ctloutput,
.pr_abort = uipc_abort,
.pr_accept = uipc_peeraddr,
.pr_attach = uipc_attach,
.pr_bind = uipc_bind,
.pr_bindat = uipc_bindat,
.pr_connect = uipc_connect,
.pr_connectat = uipc_connectat,
.pr_connect2 = uipc_connect2,
.pr_detach = uipc_detach,
.pr_disconnect = uipc_disconnect,
.pr_listen = uipc_listen,
.pr_peeraddr = uipc_peeraddr,
.pr_rcvd = uipc_rcvd,
.pr_send = uipc_send,
.pr_ready = uipc_ready,
.pr_sense = uipc_sense,
.pr_shutdown = uipc_shutdown,
.pr_sockaddr = uipc_sockaddr,
.pr_soreceive = soreceive_generic,
.pr_close = uipc_close,
};
static struct protosw dgramproto = {
.pr_type = SOCK_DGRAM,
.pr_flags = PR_ATOMIC | PR_ADDR | PR_CAPATTACH | PR_SOCKBUF,
.pr_ctloutput = &uipc_ctloutput,
.pr_abort = uipc_abort,
.pr_accept = uipc_peeraddr,
.pr_attach = uipc_attach,
.pr_bind = uipc_bind,
.pr_bindat = uipc_bindat,
.pr_connect = uipc_connect,
.pr_connectat = uipc_connectat,
.pr_connect2 = uipc_connect2,
.pr_detach = uipc_detach,
.pr_disconnect = uipc_disconnect,
.pr_peeraddr = uipc_peeraddr,
.pr_sosend = uipc_sosend_dgram,
.pr_sense = uipc_sense,
.pr_shutdown = uipc_shutdown,
.pr_sockaddr = uipc_sockaddr,
.pr_soreceive = uipc_soreceive_dgram,
.pr_close = uipc_close,
};
static struct protosw seqpacketproto = {
.pr_type = SOCK_SEQPACKET,
/*
* XXXRW: For now, PR_ADDR because soreceive will bump into them
* due to our use of sbappendaddr. A new sbappend variants is needed
* that supports both atomic record writes and control data.
*/
.pr_flags = PR_ADDR | PR_ATOMIC | PR_CONNREQUIRED |
PR_WANTRCVD | PR_CAPATTACH,
.pr_ctloutput = &uipc_ctloutput,
.pr_abort = uipc_abort,
.pr_accept = uipc_peeraddr,
.pr_attach = uipc_attach,
.pr_bind = uipc_bind,
.pr_bindat = uipc_bindat,
.pr_connect = uipc_connect,
.pr_connectat = uipc_connectat,
.pr_connect2 = uipc_connect2,
.pr_detach = uipc_detach,
.pr_disconnect = uipc_disconnect,
.pr_listen = uipc_listen,
.pr_peeraddr = uipc_peeraddr,
.pr_rcvd = uipc_rcvd,
.pr_send = uipc_send,
.pr_sense = uipc_sense,
.pr_shutdown = uipc_shutdown,
.pr_sockaddr = uipc_sockaddr,
.pr_soreceive = soreceive_generic, /* XXX: or...? */
.pr_close = uipc_close,
};
static struct domain localdomain = {
.dom_family = AF_LOCAL,
.dom_name = "local",
.dom_externalize = unp_externalize,
.dom_nprotosw = 3,
.dom_protosw = {
&streamproto,
&dgramproto,
&seqpacketproto,
}
};
DOMAIN_SET(local);
/*
* A helper function called by VFS before socket-type vnode reclamation.
* For an active vnode it clears unp_vnode pointer and decrements unp_vnode
* use count.
*/
void
vfs_unp_reclaim(struct vnode *vp)
{
struct unpcb *unp;
int active;
struct mtx *vplock;
ASSERT_VOP_ELOCKED(vp, "vfs_unp_reclaim");
KASSERT(vp->v_type == VSOCK,
("vfs_unp_reclaim: vp->v_type != VSOCK"));
active = 0;
vplock = mtx_pool_find(mtxpool_sleep, vp);
mtx_lock(vplock);
VOP_UNP_CONNECT(vp, &unp);
if (unp == NULL)
goto done;
UNP_PCB_LOCK(unp);
if (unp->unp_vnode == vp) {
VOP_UNP_DETACH(vp);
unp->unp_vnode = NULL;
active = 1;
}
UNP_PCB_UNLOCK(unp);
done:
mtx_unlock(vplock);
if (active)
vunref(vp);
}
#ifdef DDB
static void
db_print_indent(int indent)
{
int i;
for (i = 0; i < indent; i++)
db_printf(" ");
}
static void
db_print_unpflags(int unp_flags)
{
int comma;
comma = 0;
if (unp_flags & UNP_HAVEPC) {
db_printf("%sUNP_HAVEPC", comma ? ", " : "");
comma = 1;
}
if (unp_flags & UNP_WANTCRED_ALWAYS) {
db_printf("%sUNP_WANTCRED_ALWAYS", comma ? ", " : "");
comma = 1;
}
if (unp_flags & UNP_WANTCRED_ONESHOT) {
db_printf("%sUNP_WANTCRED_ONESHOT", comma ? ", " : "");
comma = 1;
}
if (unp_flags & UNP_CONNECTING) {
db_printf("%sUNP_CONNECTING", comma ? ", " : "");
comma = 1;
}
if (unp_flags & UNP_BINDING) {
db_printf("%sUNP_BINDING", comma ? ", " : "");
comma = 1;
}
}
static void
db_print_xucred(int indent, struct xucred *xu)
{
int comma, i;
db_print_indent(indent);
db_printf("cr_version: %u cr_uid: %u cr_pid: %d cr_ngroups: %d\n",
xu->cr_version, xu->cr_uid, xu->cr_pid, xu->cr_ngroups);
db_print_indent(indent);
db_printf("cr_groups: ");
comma = 0;
for (i = 0; i < xu->cr_ngroups; i++) {
db_printf("%s%u", comma ? ", " : "", xu->cr_groups[i]);
comma = 1;
}
db_printf("\n");
}
static void
db_print_unprefs(int indent, struct unp_head *uh)
{
struct unpcb *unp;
int counter;
counter = 0;
LIST_FOREACH(unp, uh, unp_reflink) {
if (counter % 4 == 0)
db_print_indent(indent);
db_printf("%p ", unp);
if (counter % 4 == 3)
db_printf("\n");
counter++;
}
if (counter != 0 && counter % 4 != 0)
db_printf("\n");
}
DB_SHOW_COMMAND(unpcb, db_show_unpcb)
{
struct unpcb *unp;
if (!have_addr) {
db_printf("usage: show unpcb <addr>\n");
return;
}
unp = (struct unpcb *)addr;
db_printf("unp_socket: %p unp_vnode: %p\n", unp->unp_socket,
unp->unp_vnode);
db_printf("unp_ino: %ju unp_conn: %p\n", (uintmax_t)unp->unp_ino,
unp->unp_conn);
db_printf("unp_refs:\n");
db_print_unprefs(2, &unp->unp_refs);
/* XXXRW: Would be nice to print the full address, if any. */
db_printf("unp_addr: %p\n", unp->unp_addr);
db_printf("unp_gencnt: %llu\n",
(unsigned long long)unp->unp_gencnt);
db_printf("unp_flags: %x (", unp->unp_flags);
db_print_unpflags(unp->unp_flags);
db_printf(")\n");
db_printf("unp_peercred:\n");
db_print_xucred(2, &unp->unp_peercred);
db_printf("unp_refcount: %u\n", unp->unp_refcount);
}
#endif
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