/sys/kern/uipc_socket.c
C | 3579 lines | 2567 code | 327 blank | 685 comment | 712 complexity | a56d623563f9d08cb916691cee72b1db MD5 | raw file
Possible License(s): MPL-2.0-no-copyleft-exception, 0BSD, BSD-3-Clause
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- /*-
- * Copyright (c) 1982, 1986, 1988, 1990, 1993
- * The Regents of the University of California.
- * Copyright (c) 2004 The FreeBSD Foundation
- * Copyright (c) 2004-2008 Robert N. M. Watson
- * All rights reserved.
- *
- * 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.
- * 4. 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.
- *
- * @(#)uipc_socket.c 8.3 (Berkeley) 4/15/94
- */
- /*
- * Comments on the socket life cycle:
- *
- * soalloc() sets of socket layer state for a socket, called only by
- * socreate() and sonewconn(). Socket layer private.
- *
- * sodealloc() tears down socket layer state for a socket, called only by
- * sofree() and sonewconn(). Socket layer private.
- *
- * pru_attach() associates protocol layer state with an allocated socket;
- * called only once, may fail, aborting socket allocation. This is called
- * from socreate() and sonewconn(). Socket layer private.
- *
- * pru_detach() disassociates protocol layer state from an attached socket,
- * and will be called exactly once for sockets in which pru_attach() has
- * been successfully called. If pru_attach() returned an error,
- * pru_detach() will not be called. Socket layer private.
- *
- * pru_abort() and pru_close() notify the protocol layer that the last
- * consumer of a socket is starting to tear down the socket, and that the
- * protocol should terminate the connection. Historically, pru_abort() also
- * detached protocol state from the socket state, but this is no longer the
- * case.
- *
- * socreate() creates a socket and attaches protocol state. This is a public
- * interface that may be used by socket layer consumers to create new
- * sockets.
- *
- * sonewconn() creates a socket and attaches protocol state. This is a
- * public interface that may be used by protocols to create new sockets when
- * a new connection is received and will be available for accept() on a
- * listen socket.
- *
- * soclose() destroys a socket after possibly waiting for it to disconnect.
- * This is a public interface that socket consumers should use to close and
- * release a socket when done with it.
- *
- * soabort() destroys a socket without waiting for it to disconnect (used
- * only for incoming connections that are already partially or fully
- * connected). This is used internally by the socket layer when clearing
- * listen socket queues (due to overflow or close on the listen socket), but
- * is also a public interface protocols may use to abort connections in
- * their incomplete listen queues should they no longer be required. Sockets
- * placed in completed connection listen queues should not be aborted for
- * reasons described in the comment above the soclose() implementation. This
- * is not a general purpose close routine, and except in the specific
- * circumstances described here, should not be used.
- *
- * sofree() will free a socket and its protocol state if all references on
- * the socket have been released, and is the public interface to attempt to
- * free a socket when a reference is removed. This is a socket layer private
- * interface.
- *
- * NOTE: In addition to socreate() and soclose(), which provide a single
- * socket reference to the consumer to be managed as required, there are two
- * calls to explicitly manage socket references, soref(), and sorele().
- * Currently, these are generally required only when transitioning a socket
- * from a listen queue to a file descriptor, in order to prevent garbage
- * collection of the socket at an untimely moment. For a number of reasons,
- * these interfaces are not preferred, and should be avoided.
- */
- #include <sys/cdefs.h>
- __FBSDID("$FreeBSD: src/sys/kern/uipc_socket.c,v 1.348 2010/05/27 15:27:31 rwatson Exp $");
- #include "opt_inet.h"
- #include "opt_inet6.h"
- #include "opt_zero.h"
- #include "opt_compat.h"
- #include <sys/param.h>
- #include <sys/systm.h>
- #include <sys/fcntl.h>
- #include <sys/limits.h>
- #include <sys/lock.h>
- #include <sys/mac.h>
- #include <sys/malloc.h>
- #include <sys/mbuf.h>
- #include <sys/mutex.h>
- #include <sys/domain.h>
- #include <sys/file.h> /* for struct knote */
- #include <sys/kernel.h>
- #include <sys/event.h>
- #include <sys/eventhandler.h>
- #include <sys/poll.h>
- #include <sys/proc.h>
- #include <sys/protosw.h>
- #include <sys/socket.h>
- #include <sys/socketvar.h>
- #include <sys/resourcevar.h>
- #include <net/route.h>
- #include <sys/signalvar.h>
- #include <sys/stat.h>
- #include <sys/sx.h>
- #include <sys/sysctl.h>
- #include <sys/uio.h>
- #include <sys/jail.h>
- #include <net/vnet.h>
- #include <security/mac/mac_framework.h>
- #include <vm/uma.h>
- #ifdef COMPAT_FREEBSD32
- #include <sys/mount.h>
- #include <sys/sysent.h>
- #include <compat/freebsd32/freebsd32.h>
- #endif
- static int soreceive_rcvoob(struct socket *so, struct uio *uio,
- int flags);
- static void filt_sordetach(struct knote *kn);
- static int filt_soread(struct knote *kn, long hint);
- static void filt_sowdetach(struct knote *kn);
- static int filt_sowrite(struct knote *kn, long hint);
- static int filt_solisten(struct knote *kn, long hint);
- static struct filterops solisten_filtops = {
- .f_isfd = 1,
- .f_detach = filt_sordetach,
- .f_event = filt_solisten,
- };
- static struct filterops soread_filtops = {
- .f_isfd = 1,
- .f_detach = filt_sordetach,
- .f_event = filt_soread,
- };
- static struct filterops sowrite_filtops = {
- .f_isfd = 1,
- .f_detach = filt_sowdetach,
- .f_event = filt_sowrite,
- };
- uma_zone_t socket_zone;
- so_gen_t so_gencnt; /* generation count for sockets */
- int maxsockets;
- MALLOC_DEFINE(M_SONAME, "soname", "socket name");
- MALLOC_DEFINE(M_PCB, "pcb", "protocol control block");
- static int somaxconn = SOMAXCONN;
- static int sysctl_somaxconn(SYSCTL_HANDLER_ARGS);
- /* XXX: we dont have SYSCTL_USHORT */
- SYSCTL_PROC(_kern_ipc, KIPC_SOMAXCONN, somaxconn, CTLTYPE_UINT | CTLFLAG_RW,
- 0, sizeof(int), sysctl_somaxconn, "I", "Maximum pending socket connection "
- "queue size");
- static int numopensockets;
- SYSCTL_INT(_kern_ipc, OID_AUTO, numopensockets, CTLFLAG_RD,
- &numopensockets, 0, "Number of open sockets");
- #ifdef ZERO_COPY_SOCKETS
- /* These aren't static because they're used in other files. */
- int so_zero_copy_send = 1;
- int so_zero_copy_receive = 1;
- SYSCTL_NODE(_kern_ipc, OID_AUTO, zero_copy, CTLFLAG_RD, 0,
- "Zero copy controls");
- SYSCTL_INT(_kern_ipc_zero_copy, OID_AUTO, receive, CTLFLAG_RW,
- &so_zero_copy_receive, 0, "Enable zero copy receive");
- SYSCTL_INT(_kern_ipc_zero_copy, OID_AUTO, send, CTLFLAG_RW,
- &so_zero_copy_send, 0, "Enable zero copy send");
- #endif /* ZERO_COPY_SOCKETS */
- /*
- * accept_mtx locks down per-socket fields relating to accept queues. See
- * socketvar.h for an annotation of the protected fields of struct socket.
- */
- struct mtx accept_mtx;
- MTX_SYSINIT(accept_mtx, &accept_mtx, "accept", MTX_DEF);
- /*
- * so_global_mtx protects so_gencnt, numopensockets, and the per-socket
- * so_gencnt field.
- */
- static struct mtx so_global_mtx;
- MTX_SYSINIT(so_global_mtx, &so_global_mtx, "so_glabel", MTX_DEF);
- /*
- * General IPC sysctl name space, used by sockets and a variety of other IPC
- * types.
- */
- SYSCTL_NODE(_kern, KERN_IPC, ipc, CTLFLAG_RW, 0, "IPC");
- /*
- * Sysctl to get and set the maximum global sockets limit. Notify protocols
- * of the change so that they can update their dependent limits as required.
- */
- static int
- sysctl_maxsockets(SYSCTL_HANDLER_ARGS)
- {
- int error, newmaxsockets;
- newmaxsockets = maxsockets;
- error = sysctl_handle_int(oidp, &newmaxsockets, 0, req);
- if (error == 0 && req->newptr) {
- if (newmaxsockets > maxsockets) {
- maxsockets = newmaxsockets;
- if (maxsockets > ((maxfiles / 4) * 3)) {
- maxfiles = (maxsockets * 5) / 4;
- maxfilesperproc = (maxfiles * 9) / 10;
- }
- EVENTHANDLER_INVOKE(maxsockets_change);
- } else
- error = EINVAL;
- }
- return (error);
- }
- SYSCTL_PROC(_kern_ipc, OID_AUTO, maxsockets, CTLTYPE_INT|CTLFLAG_RW,
- &maxsockets, 0, sysctl_maxsockets, "IU",
- "Maximum number of sockets avaliable");
- /*
- * Initialise maxsockets. This SYSINIT must be run after
- * tunable_mbinit().
- */
- static void
- init_maxsockets(void *ignored)
- {
- TUNABLE_INT_FETCH("kern.ipc.maxsockets", &maxsockets);
- maxsockets = imax(maxsockets, imax(maxfiles, nmbclusters));
- }
- SYSINIT(param, SI_SUB_TUNABLES, SI_ORDER_ANY, init_maxsockets, NULL);
- /*
- * Socket operation routines. These routines are called by the routines in
- * sys_socket.c or from a system process, and implement the semantics of
- * socket operations by switching out to the protocol specific routines.
- */
- /*
- * Get a socket structure from our zone, and initialize it. Note that it
- * would probably be better to allocate socket and PCB at the same time, but
- * I'm not convinced that all the protocols can be easily modified to do
- * this.
- *
- * soalloc() returns a socket with a ref count of 0.
- */
- static struct socket *
- soalloc(struct vnet *vnet)
- {
- struct socket *so;
- so = uma_zalloc(socket_zone, M_NOWAIT | M_ZERO);
- if (so == NULL)
- return (NULL);
- #ifdef MAC
- if (mac_socket_init(so, M_NOWAIT) != 0) {
- uma_zfree(socket_zone, so);
- return (NULL);
- }
- #endif
- SOCKBUF_LOCK_INIT(&so->so_snd, "so_snd");
- SOCKBUF_LOCK_INIT(&so->so_rcv, "so_rcv");
- sx_init(&so->so_snd.sb_sx, "so_snd_sx");
- sx_init(&so->so_rcv.sb_sx, "so_rcv_sx");
- TAILQ_INIT(&so->so_aiojobq);
- mtx_lock(&so_global_mtx);
- so->so_gencnt = ++so_gencnt;
- ++numopensockets;
- #ifdef VIMAGE
- vnet->vnet_sockcnt++;
- so->so_vnet = vnet;
- #endif
- mtx_unlock(&so_global_mtx);
- return (so);
- }
- /*
- * Free the storage associated with a socket at the socket layer, tear down
- * locks, labels, etc. All protocol state is assumed already to have been
- * torn down (and possibly never set up) by the caller.
- */
- static void
- sodealloc(struct socket *so)
- {
- KASSERT(so->so_count == 0, ("sodealloc(): so_count %d", so->so_count));
- KASSERT(so->so_pcb == NULL, ("sodealloc(): so_pcb != NULL"));
- mtx_lock(&so_global_mtx);
- so->so_gencnt = ++so_gencnt;
- --numopensockets; /* Could be below, but faster here. */
- #ifdef VIMAGE
- so->so_vnet->vnet_sockcnt--;
- #endif
- mtx_unlock(&so_global_mtx);
- if (so->so_rcv.sb_hiwat)
- (void)chgsbsize(so->so_cred->cr_uidinfo,
- &so->so_rcv.sb_hiwat, 0, RLIM_INFINITY);
- if (so->so_snd.sb_hiwat)
- (void)chgsbsize(so->so_cred->cr_uidinfo,
- &so->so_snd.sb_hiwat, 0, RLIM_INFINITY);
- #ifdef INET
- /* remove acccept filter if one is present. */
- if (so->so_accf != NULL)
- do_setopt_accept_filter(so, NULL);
- #endif
- #ifdef MAC
- mac_socket_destroy(so);
- #endif
- crfree(so->so_cred);
- sx_destroy(&so->so_snd.sb_sx);
- sx_destroy(&so->so_rcv.sb_sx);
- SOCKBUF_LOCK_DESTROY(&so->so_snd);
- SOCKBUF_LOCK_DESTROY(&so->so_rcv);
- uma_zfree(socket_zone, so);
- }
- /*
- * socreate returns a socket with a ref count of 1. The socket should be
- * closed with soclose().
- */
- int
- socreate(int dom, struct socket **aso, int type, int proto,
- struct ucred *cred, struct thread *td)
- {
- struct protosw *prp;
- struct socket *so;
- int error;
- if (proto)
- prp = pffindproto(dom, proto, type);
- else
- prp = pffindtype(dom, type);
- if (prp == NULL || prp->pr_usrreqs->pru_attach == NULL ||
- prp->pr_usrreqs->pru_attach == pru_attach_notsupp)
- return (EPROTONOSUPPORT);
- if (prison_check_af(cred, prp->pr_domain->dom_family) != 0)
- return (EPROTONOSUPPORT);
- if (prp->pr_type != type)
- return (EPROTOTYPE);
- so = soalloc(CRED_TO_VNET(cred));
- if (so == NULL)
- return (ENOBUFS);
- TAILQ_INIT(&so->so_incomp);
- TAILQ_INIT(&so->so_comp);
- so->so_type = type;
- so->so_cred = crhold(cred);
- if ((prp->pr_domain->dom_family == PF_INET) ||
- (prp->pr_domain->dom_family == PF_ROUTE))
- so->so_fibnum = td->td_proc->p_fibnum;
- else
- so->so_fibnum = 0;
- so->so_proto = prp;
- #ifdef MAC
- mac_socket_create(cred, so);
- #endif
- knlist_init_mtx(&so->so_rcv.sb_sel.si_note, SOCKBUF_MTX(&so->so_rcv));
- knlist_init_mtx(&so->so_snd.sb_sel.si_note, SOCKBUF_MTX(&so->so_snd));
- so->so_count = 1;
- /*
- * Auto-sizing of socket buffers is managed by the protocols and
- * the appropriate flags must be set in the pru_attach function.
- */
- CURVNET_SET(so->so_vnet);
- error = (*prp->pr_usrreqs->pru_attach)(so, proto, td);
- CURVNET_RESTORE();
- if (error) {
- KASSERT(so->so_count == 1, ("socreate: so_count %d",
- so->so_count));
- so->so_count = 0;
- sodealloc(so);
- return (error);
- }
- *aso = so;
- return (0);
- }
- #ifdef REGRESSION
- static int regression_sonewconn_earlytest = 1;
- SYSCTL_INT(_regression, OID_AUTO, sonewconn_earlytest, CTLFLAG_RW,
- ®ression_sonewconn_earlytest, 0, "Perform early sonewconn limit test");
- #endif
- /*
- * When an attempt at a new connection is noted on a socket which accepts
- * connections, sonewconn is called. If the connection is possible (subject
- * to space constraints, etc.) then we allocate a new structure, propoerly
- * linked into the data structure of the original socket, and return this.
- * Connstatus may be 0, or SO_ISCONFIRMING, or SO_ISCONNECTED.
- *
- * Note: the ref count on the socket is 0 on return.
- */
- struct socket *
- sonewconn(struct socket *head, int connstatus)
- {
- struct socket *so;
- int over;
- ACCEPT_LOCK();
- over = (head->so_qlen > 3 * head->so_qlimit / 2);
- ACCEPT_UNLOCK();
- #ifdef REGRESSION
- if (regression_sonewconn_earlytest && over)
- #else
- if (over)
- #endif
- return (NULL);
- VNET_ASSERT(head->so_vnet);
- so = soalloc(head->so_vnet);
- if (so == NULL)
- return (NULL);
- if ((head->so_options & SO_ACCEPTFILTER) != 0)
- connstatus = 0;
- so->so_head = head;
- so->so_type = head->so_type;
- so->so_options = head->so_options &~ SO_ACCEPTCONN;
- so->so_linger = head->so_linger;
- so->so_state = head->so_state | SS_NOFDREF;
- so->so_fibnum = head->so_fibnum;
- so->so_proto = head->so_proto;
- so->so_cred = crhold(head->so_cred);
- #ifdef MAC
- mac_socket_newconn(head, so);
- #endif
- knlist_init_mtx(&so->so_rcv.sb_sel.si_note, SOCKBUF_MTX(&so->so_rcv));
- knlist_init_mtx(&so->so_snd.sb_sel.si_note, SOCKBUF_MTX(&so->so_snd));
- if (soreserve(so, head->so_snd.sb_hiwat, head->so_rcv.sb_hiwat) ||
- (*so->so_proto->pr_usrreqs->pru_attach)(so, 0, NULL)) {
- sodealloc(so);
- return (NULL);
- }
- so->so_rcv.sb_lowat = head->so_rcv.sb_lowat;
- so->so_snd.sb_lowat = head->so_snd.sb_lowat;
- so->so_rcv.sb_timeo = head->so_rcv.sb_timeo;
- so->so_snd.sb_timeo = head->so_snd.sb_timeo;
- so->so_rcv.sb_flags |= head->so_rcv.sb_flags & SB_AUTOSIZE;
- so->so_snd.sb_flags |= head->so_snd.sb_flags & SB_AUTOSIZE;
- so->so_state |= connstatus;
- ACCEPT_LOCK();
- if (connstatus) {
- TAILQ_INSERT_TAIL(&head->so_comp, so, so_list);
- so->so_qstate |= SQ_COMP;
- head->so_qlen++;
- } else {
- /*
- * Keep removing sockets from the head until there's room for
- * us to insert on the tail. In pre-locking revisions, this
- * was a simple if(), but as we could be racing with other
- * threads and soabort() requires dropping locks, we must
- * loop waiting for the condition to be true.
- */
- while (head->so_incqlen > head->so_qlimit) {
- struct socket *sp;
- sp = TAILQ_FIRST(&head->so_incomp);
- TAILQ_REMOVE(&head->so_incomp, sp, so_list);
- head->so_incqlen--;
- sp->so_qstate &= ~SQ_INCOMP;
- sp->so_head = NULL;
- ACCEPT_UNLOCK();
- soabort(sp);
- ACCEPT_LOCK();
- }
- TAILQ_INSERT_TAIL(&head->so_incomp, so, so_list);
- so->so_qstate |= SQ_INCOMP;
- head->so_incqlen++;
- }
- ACCEPT_UNLOCK();
- if (connstatus) {
- sorwakeup(head);
- wakeup_one(&head->so_timeo);
- }
- return (so);
- }
- int
- sobind(struct socket *so, struct sockaddr *nam, struct thread *td)
- {
- int error;
- CURVNET_SET(so->so_vnet);
- error = (*so->so_proto->pr_usrreqs->pru_bind)(so, nam, td);
- CURVNET_RESTORE();
- return error;
- }
- /*
- * solisten() transitions a socket from a non-listening state to a listening
- * state, but can also be used to update the listen queue depth on an
- * existing listen socket. The protocol will call back into the sockets
- * layer using solisten_proto_check() and solisten_proto() to check and set
- * socket-layer listen state. Call backs are used so that the protocol can
- * acquire both protocol and socket layer locks in whatever order is required
- * by the protocol.
- *
- * Protocol implementors are advised to hold the socket lock across the
- * socket-layer test and set to avoid races at the socket layer.
- */
- int
- solisten(struct socket *so, int backlog, struct thread *td)
- {
- return ((*so->so_proto->pr_usrreqs->pru_listen)(so, backlog, td));
- }
- int
- solisten_proto_check(struct socket *so)
- {
- SOCK_LOCK_ASSERT(so);
- if (so->so_state & (SS_ISCONNECTED | SS_ISCONNECTING |
- SS_ISDISCONNECTING))
- return (EINVAL);
- return (0);
- }
- void
- solisten_proto(struct socket *so, int backlog)
- {
- SOCK_LOCK_ASSERT(so);
- if (backlog < 0 || backlog > somaxconn)
- backlog = somaxconn;
- so->so_qlimit = backlog;
- so->so_options |= SO_ACCEPTCONN;
- }
- /*
- * Attempt to free a socket. This should really be sotryfree().
- *
- * sofree() will succeed if:
- *
- * - There are no outstanding file descriptor references or related consumers
- * (so_count == 0).
- *
- * - The socket has been closed by user space, if ever open (SS_NOFDREF).
- *
- * - The protocol does not have an outstanding strong reference on the socket
- * (SS_PROTOREF).
- *
- * - The socket is not in a completed connection queue, so a process has been
- * notified that it is present. If it is removed, the user process may
- * block in accept() despite select() saying the socket was ready.
- *
- * Otherwise, it will quietly abort so that a future call to sofree(), when
- * conditions are right, can succeed.
- */
- void
- sofree(struct socket *so)
- {
- struct protosw *pr = so->so_proto;
- struct socket *head;
- ACCEPT_LOCK_ASSERT();
- SOCK_LOCK_ASSERT(so);
- if ((so->so_state & SS_NOFDREF) == 0 || so->so_count != 0 ||
- (so->so_state & SS_PROTOREF) || (so->so_qstate & SQ_COMP)) {
- SOCK_UNLOCK(so);
- ACCEPT_UNLOCK();
- return;
- }
- head = so->so_head;
- if (head != NULL) {
- KASSERT((so->so_qstate & SQ_COMP) != 0 ||
- (so->so_qstate & SQ_INCOMP) != 0,
- ("sofree: so_head != NULL, but neither SQ_COMP nor "
- "SQ_INCOMP"));
- KASSERT((so->so_qstate & SQ_COMP) == 0 ||
- (so->so_qstate & SQ_INCOMP) == 0,
- ("sofree: so->so_qstate is SQ_COMP and also SQ_INCOMP"));
- TAILQ_REMOVE(&head->so_incomp, so, so_list);
- head->so_incqlen--;
- so->so_qstate &= ~SQ_INCOMP;
- so->so_head = NULL;
- }
- KASSERT((so->so_qstate & SQ_COMP) == 0 &&
- (so->so_qstate & SQ_INCOMP) == 0,
- ("sofree: so_head == NULL, but still SQ_COMP(%d) or SQ_INCOMP(%d)",
- so->so_qstate & SQ_COMP, so->so_qstate & SQ_INCOMP));
- if (so->so_options & SO_ACCEPTCONN) {
- KASSERT((TAILQ_EMPTY(&so->so_comp)), ("sofree: so_comp populated"));
- KASSERT((TAILQ_EMPTY(&so->so_incomp)), ("sofree: so_comp populated"));
- }
- SOCK_UNLOCK(so);
- ACCEPT_UNLOCK();
- if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose != NULL)
- (*pr->pr_domain->dom_dispose)(so->so_rcv.sb_mb);
- if (pr->pr_usrreqs->pru_detach != NULL)
- (*pr->pr_usrreqs->pru_detach)(so);
- /*
- * From this point on, we assume that no other references to this
- * socket exist anywhere else in the stack. Therefore, no locks need
- * to be acquired or held.
- *
- * We used to do a lot of socket buffer and socket locking here, as
- * well as invoke sorflush() and perform wakeups. The direct call to
- * dom_dispose() and sbrelease_internal() are an inlining of what was
- * necessary from sorflush().
- *
- * Notice that the socket buffer and kqueue state are torn down
- * before calling pru_detach. This means that protocols shold not
- * assume they can perform socket wakeups, etc, in their detach code.
- */
- sbdestroy(&so->so_snd, so);
- sbdestroy(&so->so_rcv, so);
- knlist_destroy(&so->so_rcv.sb_sel.si_note);
- knlist_destroy(&so->so_snd.sb_sel.si_note);
- sodealloc(so);
- }
- /*
- * Close a socket on last file table reference removal. Initiate disconnect
- * if connected. Free socket when disconnect complete.
- *
- * This function will sorele() the socket. Note that soclose() may be called
- * prior to the ref count reaching zero. The actual socket structure will
- * not be freed until the ref count reaches zero.
- */
- int
- soclose(struct socket *so)
- {
- int error = 0;
- KASSERT(!(so->so_state & SS_NOFDREF), ("soclose: SS_NOFDREF on enter"));
- CURVNET_SET(so->so_vnet);
- funsetown(&so->so_sigio);
- if (so->so_state & SS_ISCONNECTED) {
- if ((so->so_state & SS_ISDISCONNECTING) == 0) {
- error = sodisconnect(so);
- if (error) {
- if (error == ENOTCONN)
- error = 0;
- goto drop;
- }
- }
- if (so->so_options & SO_LINGER) {
- if ((so->so_state & SS_ISDISCONNECTING) &&
- (so->so_state & SS_NBIO))
- goto drop;
- while (so->so_state & SS_ISCONNECTED) {
- error = tsleep(&so->so_timeo,
- PSOCK | PCATCH, "soclos", so->so_linger * hz);
- if (error)
- break;
- }
- }
- }
- drop:
- if (so->so_proto->pr_usrreqs->pru_close != NULL)
- (*so->so_proto->pr_usrreqs->pru_close)(so);
- if (so->so_options & SO_ACCEPTCONN) {
- struct socket *sp;
- ACCEPT_LOCK();
- while ((sp = TAILQ_FIRST(&so->so_incomp)) != NULL) {
- TAILQ_REMOVE(&so->so_incomp, sp, so_list);
- so->so_incqlen--;
- sp->so_qstate &= ~SQ_INCOMP;
- sp->so_head = NULL;
- ACCEPT_UNLOCK();
- soabort(sp);
- ACCEPT_LOCK();
- }
- while ((sp = TAILQ_FIRST(&so->so_comp)) != NULL) {
- TAILQ_REMOVE(&so->so_comp, sp, so_list);
- so->so_qlen--;
- sp->so_qstate &= ~SQ_COMP;
- sp->so_head = NULL;
- ACCEPT_UNLOCK();
- soabort(sp);
- ACCEPT_LOCK();
- }
- ACCEPT_UNLOCK();
- }
- ACCEPT_LOCK();
- SOCK_LOCK(so);
- KASSERT((so->so_state & SS_NOFDREF) == 0, ("soclose: NOFDREF"));
- so->so_state |= SS_NOFDREF;
- sorele(so);
- CURVNET_RESTORE();
- return (error);
- }
- /*
- * soabort() is used to abruptly tear down a connection, such as when a
- * resource limit is reached (listen queue depth exceeded), or if a listen
- * socket is closed while there are sockets waiting to be accepted.
- *
- * This interface is tricky, because it is called on an unreferenced socket,
- * and must be called only by a thread that has actually removed the socket
- * from the listen queue it was on, or races with other threads are risked.
- *
- * This interface will call into the protocol code, so must not be called
- * with any socket locks held. Protocols do call it while holding their own
- * recursible protocol mutexes, but this is something that should be subject
- * to review in the future.
- */
- void
- soabort(struct socket *so)
- {
- /*
- * In as much as is possible, assert that no references to this
- * socket are held. This is not quite the same as asserting that the
- * current thread is responsible for arranging for no references, but
- * is as close as we can get for now.
- */
- KASSERT(so->so_count == 0, ("soabort: so_count"));
- KASSERT((so->so_state & SS_PROTOREF) == 0, ("soabort: SS_PROTOREF"));
- KASSERT(so->so_state & SS_NOFDREF, ("soabort: !SS_NOFDREF"));
- KASSERT((so->so_state & SQ_COMP) == 0, ("soabort: SQ_COMP"));
- KASSERT((so->so_state & SQ_INCOMP) == 0, ("soabort: SQ_INCOMP"));
- if (so->so_proto->pr_usrreqs->pru_abort != NULL)
- (*so->so_proto->pr_usrreqs->pru_abort)(so);
- ACCEPT_LOCK();
- SOCK_LOCK(so);
- sofree(so);
- }
- int
- soaccept(struct socket *so, struct sockaddr **nam)
- {
- int error;
- SOCK_LOCK(so);
- KASSERT((so->so_state & SS_NOFDREF) != 0, ("soaccept: !NOFDREF"));
- so->so_state &= ~SS_NOFDREF;
- SOCK_UNLOCK(so);
- error = (*so->so_proto->pr_usrreqs->pru_accept)(so, nam);
- return (error);
- }
- int
- soconnect(struct socket *so, struct sockaddr *nam, struct thread *td)
- {
- int error;
- if (so->so_options & SO_ACCEPTCONN)
- return (EOPNOTSUPP);
- CURVNET_SET(so->so_vnet);
- /*
- * If protocol is connection-based, can only connect once.
- * Otherwise, if connected, try to disconnect first. This allows
- * user to disconnect by connecting to, e.g., a null address.
- */
- if (so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING) &&
- ((so->so_proto->pr_flags & PR_CONNREQUIRED) ||
- (error = sodisconnect(so)))) {
- error = EISCONN;
- } else {
- /*
- * Prevent accumulated error from previous connection from
- * biting us.
- */
- so->so_error = 0;
- error = (*so->so_proto->pr_usrreqs->pru_connect)(so, nam, td);
- }
- CURVNET_RESTORE();
- return (error);
- }
- int
- soconnect2(struct socket *so1, struct socket *so2)
- {
- return ((*so1->so_proto->pr_usrreqs->pru_connect2)(so1, so2));
- }
- int
- sodisconnect(struct socket *so)
- {
- int error;
- if ((so->so_state & SS_ISCONNECTED) == 0)
- return (ENOTCONN);
- if (so->so_state & SS_ISDISCONNECTING)
- return (EALREADY);
- error = (*so->so_proto->pr_usrreqs->pru_disconnect)(so);
- return (error);
- }
- #ifdef ZERO_COPY_SOCKETS
- struct so_zerocopy_stats{
- int size_ok;
- int align_ok;
- int found_ifp;
- };
- struct so_zerocopy_stats so_zerocp_stats = {0,0,0};
- #include <netinet/in.h>
- #include <net/route.h>
- #include <netinet/in_pcb.h>
- #include <vm/vm.h>
- #include <vm/vm_page.h>
- #include <vm/vm_object.h>
- /*
- * sosend_copyin() is only used if zero copy sockets are enabled. Otherwise
- * sosend_dgram() and sosend_generic() use m_uiotombuf().
- *
- * sosend_copyin() accepts a uio and prepares an mbuf chain holding part or
- * all of the data referenced by the uio. If desired, it uses zero-copy.
- * *space will be updated to reflect data copied in.
- *
- * NB: If atomic I/O is requested, the caller must already have checked that
- * space can hold resid bytes.
- *
- * NB: In the event of an error, the caller may need to free the partial
- * chain pointed to by *mpp. The contents of both *uio and *space may be
- * modified even in the case of an error.
- */
- static int
- sosend_copyin(struct uio *uio, struct mbuf **retmp, int atomic, long *space,
- int flags)
- {
- struct mbuf *m, **mp, *top;
- long len, resid;
- int error;
- #ifdef ZERO_COPY_SOCKETS
- int cow_send;
- #endif
- *retmp = top = NULL;
- mp = ⊤
- len = 0;
- resid = uio->uio_resid;
- error = 0;
- do {
- #ifdef ZERO_COPY_SOCKETS
- cow_send = 0;
- #endif /* ZERO_COPY_SOCKETS */
- if (resid >= MINCLSIZE) {
- #ifdef ZERO_COPY_SOCKETS
- if (top == NULL) {
- m = m_gethdr(M_WAITOK, MT_DATA);
- m->m_pkthdr.len = 0;
- m->m_pkthdr.rcvif = NULL;
- } else
- m = m_get(M_WAITOK, MT_DATA);
- if (so_zero_copy_send &&
- resid>=PAGE_SIZE &&
- *space>=PAGE_SIZE &&
- uio->uio_iov->iov_len>=PAGE_SIZE) {
- so_zerocp_stats.size_ok++;
- so_zerocp_stats.align_ok++;
- cow_send = socow_setup(m, uio);
- len = cow_send;
- }
- if (!cow_send) {
- m_clget(m, M_WAITOK);
- len = min(min(MCLBYTES, resid), *space);
- }
- #else /* ZERO_COPY_SOCKETS */
- if (top == NULL) {
- m = m_getcl(M_WAIT, MT_DATA, M_PKTHDR);
- m->m_pkthdr.len = 0;
- m->m_pkthdr.rcvif = NULL;
- } else
- m = m_getcl(M_WAIT, MT_DATA, 0);
- len = min(min(MCLBYTES, resid), *space);
- #endif /* ZERO_COPY_SOCKETS */
- } else {
- if (top == NULL) {
- m = m_gethdr(M_WAIT, MT_DATA);
- m->m_pkthdr.len = 0;
- m->m_pkthdr.rcvif = NULL;
- len = min(min(MHLEN, resid), *space);
- /*
- * For datagram protocols, leave room
- * for protocol headers in first mbuf.
- */
- if (atomic && m && len < MHLEN)
- MH_ALIGN(m, len);
- } else {
- m = m_get(M_WAIT, MT_DATA);
- len = min(min(MLEN, resid), *space);
- }
- }
- if (m == NULL) {
- error = ENOBUFS;
- goto out;
- }
- *space -= len;
- #ifdef ZERO_COPY_SOCKETS
- if (cow_send)
- error = 0;
- else
- #endif /* ZERO_COPY_SOCKETS */
- error = uiomove(mtod(m, void *), (int)len, uio);
- resid = uio->uio_resid;
- m->m_len = len;
- *mp = m;
- top->m_pkthdr.len += len;
- if (error)
- goto out;
- mp = &m->m_next;
- if (resid <= 0) {
- if (flags & MSG_EOR)
- top->m_flags |= M_EOR;
- break;
- }
- } while (*space > 0 && atomic);
- out:
- *retmp = top;
- return (error);
- }
- #endif /*ZERO_COPY_SOCKETS*/
- #define SBLOCKWAIT(f) (((f) & MSG_DONTWAIT) ? 0 : SBL_WAIT)
- int
- sosend_dgram(struct socket *so, struct sockaddr *addr, struct uio *uio,
- struct mbuf *top, struct mbuf *control, int flags, struct thread *td)
- {
- long space, resid;
- int clen = 0, error, dontroute;
- #ifdef ZERO_COPY_SOCKETS
- int atomic = sosendallatonce(so) || top;
- #endif
- KASSERT(so->so_type == SOCK_DGRAM, ("sodgram_send: !SOCK_DGRAM"));
- KASSERT(so->so_proto->pr_flags & PR_ATOMIC,
- ("sodgram_send: !PR_ATOMIC"));
- if (uio != NULL)
- resid = uio->uio_resid;
- else
- resid = top->m_pkthdr.len;
- /*
- * In theory resid should be unsigned. However, space must be
- * signed, as it might be less than 0 if we over-committed, and we
- * must use a signed comparison of space and resid. On the other
- * hand, a negative resid causes us to loop sending 0-length
- * segments to the protocol.
- */
- if (resid < 0) {
- error = EINVAL;
- goto out;
- }
- dontroute =
- (flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0;
- if (td != NULL)
- td->td_ru.ru_msgsnd++;
- if (control != NULL)
- clen = control->m_len;
- SOCKBUF_LOCK(&so->so_snd);
- if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
- SOCKBUF_UNLOCK(&so->so_snd);
- error = EPIPE;
- goto out;
- }
- if (so->so_error) {
- error = so->so_error;
- so->so_error = 0;
- SOCKBUF_UNLOCK(&so->so_snd);
- goto out;
- }
- if ((so->so_state & SS_ISCONNECTED) == 0) {
- /*
- * `sendto' and `sendmsg' is allowed on a connection-based
- * socket if it supports implied connect. Return ENOTCONN if
- * not connected and no address is supplied.
- */
- if ((so->so_proto->pr_flags & PR_CONNREQUIRED) &&
- (so->so_proto->pr_flags & PR_IMPLOPCL) == 0) {
- if ((so->so_state & SS_ISCONFIRMING) == 0 &&
- !(resid == 0 && clen != 0)) {
- SOCKBUF_UNLOCK(&so->so_snd);
- error = ENOTCONN;
- goto out;
- }
- } else if (addr == NULL) {
- if (so->so_proto->pr_flags & PR_CONNREQUIRED)
- error = ENOTCONN;
- else
- error = EDESTADDRREQ;
- SOCKBUF_UNLOCK(&so->so_snd);
- goto out;
- }
- }
- /*
- * Do we need MSG_OOB support in SOCK_DGRAM? Signs here may be a
- * problem and need fixing.
- */
- space = sbspace(&so->so_snd);
- if (flags & MSG_OOB)
- space += 1024;
- space -= clen;
- SOCKBUF_UNLOCK(&so->so_snd);
- if (resid > space) {
- error = EMSGSIZE;
- goto out;
- }
- if (uio == NULL) {
- resid = 0;
- if (flags & MSG_EOR)
- top->m_flags |= M_EOR;
- } else {
- #ifdef ZERO_COPY_SOCKETS
- error = sosend_copyin(uio, &top, atomic, &space, flags);
- if (error)
- goto out;
- #else
- /*
- * Copy the data from userland into a mbuf chain.
- * If no data is to be copied in, a single empty mbuf
- * is returned.
- */
- top = m_uiotombuf(uio, M_WAITOK, space, max_hdr,
- (M_PKTHDR | ((flags & MSG_EOR) ? M_EOR : 0)));
- if (top == NULL) {
- error = EFAULT; /* only possible error */
- goto out;
- }
- space -= resid - uio->uio_resid;
- #endif
- resid = uio->uio_resid;
- }
- KASSERT(resid == 0, ("sosend_dgram: resid != 0"));
- /*
- * XXXRW: Frobbing SO_DONTROUTE here is even worse without sblock
- * than with.
- */
- if (dontroute) {
- SOCK_LOCK(so);
- so->so_options |= SO_DONTROUTE;
- SOCK_UNLOCK(so);
- }
- /*
- * XXX all the SBS_CANTSENDMORE checks previously done could be out
- * of date. We could have recieved a reset packet in an interrupt or
- * maybe we slept while doing page faults in uiomove() etc. We could
- * probably recheck again inside the locking protection here, but
- * there are probably other places that this also happens. We must
- * rethink this.
- */
- error = (*so->so_proto->pr_usrreqs->pru_send)(so,
- (flags & MSG_OOB) ? PRUS_OOB :
- /*
- * If the user set MSG_EOF, the protocol understands this flag and
- * nothing left to send then use PRU_SEND_EOF instead of PRU_SEND.
- */
- ((flags & MSG_EOF) &&
- (so->so_proto->pr_flags & PR_IMPLOPCL) &&
- (resid <= 0)) ?
- PRUS_EOF :
- /* If there is more to send set PRUS_MORETOCOME */
- (resid > 0 && space > 0) ? PRUS_MORETOCOME : 0,
- top, addr, control, td);
- if (dontroute) {
- SOCK_LOCK(so);
- so->so_options &= ~SO_DONTROUTE;
- SOCK_UNLOCK(so);
- }
- clen = 0;
- control = NULL;
- top = NULL;
- out:
- if (top != NULL)
- m_freem(top);
- if (control != NULL)
- m_freem(control);
- return (error);
- }
- /*
- * Send on a socket. If send must go all at once and message is larger than
- * send buffering, then hard error. Lock against other senders. If must go
- * all at once and not enough room now, then inform user that this would
- * block and do nothing. Otherwise, if nonblocking, send as much as
- * possible. The data to be sent is described by "uio" if nonzero, otherwise
- * by the mbuf chain "top" (which must be null if uio is not). Data provided
- * in mbuf chain must be small enough to send all at once.
- *
- * Returns nonzero on error, timeout or signal; callers must check for short
- * counts if EINTR/ERESTART are returned. Data and control buffers are freed
- * on return.
- */
- int
- sosend_generic(struct socket *so, struct sockaddr *addr, struct uio *uio,
- struct mbuf *top, struct mbuf *control, int flags, struct thread *td)
- {
- long space, resid;
- int clen = 0, error, dontroute;
- int atomic = sosendallatonce(so) || top;
- if (uio != NULL)
- resid = uio->uio_resid;
- else
- resid = top->m_pkthdr.len;
- /*
- * In theory resid should be unsigned. However, space must be
- * signed, as it might be less than 0 if we over-committed, and we
- * must use a signed comparison of space and resid. On the other
- * hand, a negative resid causes us to loop sending 0-length
- * segments to the protocol.
- *
- * Also check to make sure that MSG_EOR isn't used on SOCK_STREAM
- * type sockets since that's an error.
- */
- if (resid < 0 || (so->so_type == SOCK_STREAM && (flags & MSG_EOR))) {
- error = EINVAL;
- goto out;
- }
- dontroute =
- (flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0 &&
- (so->so_proto->pr_flags & PR_ATOMIC);
- if (td != NULL)
- td->td_ru.ru_msgsnd++;
- if (control != NULL)
- clen = control->m_len;
- error = sblock(&so->so_snd, SBLOCKWAIT(flags));
- if (error)
- goto out;
- restart:
- do {
- SOCKBUF_LOCK(&so->so_snd);
- if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
- SOCKBUF_UNLOCK(&so->so_snd);
- error = EPIPE;
- goto release;
- }
- if (so->so_error) {
- error = so->so_error;
- so->so_error = 0;
- SOCKBUF_UNLOCK(&so->so_snd);
- goto release;
- }
- if ((so->so_state & SS_ISCONNECTED) == 0) {
- /*
- * `sendto' and `sendmsg' is allowed on a connection-
- * based socket if it supports implied connect.
- * Return ENOTCONN if not connected and no address is
- * supplied.
- */
- if ((so->so_proto->pr_flags & PR_CONNREQUIRED) &&
- (so->so_proto->pr_flags & PR_IMPLOPCL) == 0) {
- if ((so->so_state & SS_ISCONFIRMING) == 0 &&
- !(resid == 0 && clen != 0)) {
- SOCKBUF_UNLOCK(&so->so_snd);
- error = ENOTCONN;
- goto release;
- }
- } else if (addr == NULL) {
- SOCKBUF_UNLOCK(&so->so_snd);
- if (so->so_proto->pr_flags & PR_CONNREQUIRED)
- error = ENOTCONN;
- else
- error = EDESTADDRREQ;
- goto release;
- }
- }
- space = sbspace(&so->so_snd);
- if (flags & MSG_OOB)
- space += 1024;
- if ((atomic && resid > so->so_snd.sb_hiwat) ||
- clen > so->so_snd.sb_hiwat) {
- SOCKBUF_UNLOCK(&so->so_snd);
- error = EMSGSIZE;
- goto release;
- }
- if (space < resid + clen &&
- (atomic || space < so->so_snd.sb_lowat || space < clen)) {
- if ((so->so_state & SS_NBIO) || (flags & MSG_NBIO)) {
- SOCKBUF_UNLOCK(&so->so_snd);
- error = EWOULDBLOCK;
- goto release;
- }
- error = sbwait(&so->so_snd);
- SOCKBUF_UNLOCK(&so->so_snd);
- if (error)
- goto release;
- goto restart;
- }
- SOCKBUF_UNLOCK(&so->so_snd);
- space -= clen;
- do {
- if (uio == NULL) {
- resid = 0;
- if (flags & MSG_EOR)
- top->m_flags |= M_EOR;
- } else {
- #ifdef ZERO_COPY_SOCKETS
- error = sosend_copyin(uio, &top, atomic,
- &space, flags);
- if (error != 0)
- goto release;
- #else
- /*
- * Copy the data from userland into a mbuf
- * chain. If no data is to be copied in,
- * a single empty mbuf is returned.
- */
- top = m_uiotombuf(uio, M_WAITOK, space,
- (atomic ? max_hdr : 0),
- (atomic ? M_PKTHDR : 0) |
- ((flags & MSG_EOR) ? M_EOR : 0));
- if (top == NULL) {
- error = EFAULT; /* only possible error */
- goto release;
- }
- space -= resid - uio->uio_resid;
- #endif
- resid = uio->uio_resid;
- }
- if (dontroute) {
- SOCK_LOCK(so);
- so->so_options |= SO_DONTROUTE;
- SOCK_UNLOCK(so);
- }
- /*
- * XXX all the SBS_CANTSENDMORE checks previously
- * done could be out of date. We could have recieved
- * a reset packet in an interrupt or maybe we slept
- * while doing page faults in uiomove() etc. We
- * could probably recheck again inside the locking
- * protection here, but there are probably other
- * places that this also happens. We must rethink
- * this.
- */
- error = (*so->so_proto->pr_usrreqs->pru_send)(so,
- (flags & MSG_OOB) ? PRUS_OOB :
- /*
- * If the user set MSG_EOF, the protocol understands
- * this flag and nothing left to send then use
- * PRU_SEND_EOF instead of PRU_SEND.
- */
- ((flags & MSG_EOF) &&
- (so->so_proto->pr_flags & PR_IMPLOPCL) &&
- (resid <= 0)) ?
- PRUS_EOF :
- /* If there is more to send set PRUS_MORETOCOME. */
- (resid > 0 && space > 0) ? PRUS_MORETOCOME : 0,
- top, addr, control, td);
- if (dontroute) {
- SOCK_LOCK(so);
- so->so_options &= ~SO_DONTROUTE;
- SOCK_UNLOCK(so);
- }
- clen = 0;
- control = NULL;
- top = NULL;
- if (error)
- goto release;
- } while (resid && space > 0);
- } while (resid);
- release:
- sbunlock(&so->so_snd);
- out:
- if (top != NULL)
- m_freem(top);
- if (control != NULL)
- m_freem(control);
- return (error);
- }
- int
- sosend(struct socket *so, struct sockaddr *addr, struct uio *uio,
- struct mbuf *top, struct mbuf *control, int flags, struct thread *td)
- {
- int error;
- CURVNET_SET(so->so_vnet);
- error = so->so_proto->pr_usrreqs->pru_sosend(so, addr, uio, top,
- control, flags, td);
- CURVNET_RESTORE();
- return (error);
- }
- /*
- * The part of soreceive() that implements reading non-inline out-of-band
- * data from a socket. For more complete comments, see soreceive(), from
- * which this code originated.
- *
- * Note that soreceive_rcvoob(), unlike the remainder of soreceive(), is
- * unable to return an mbuf chain to the caller.
- */
- static int
- soreceive_rcvoob(struct socket *so, struct uio *uio, int flags)
- {
- struct protosw *pr = so->so_proto;
- struct mbuf *m;
- int error;
- KASSERT(flags & MSG_OOB, ("soreceive_rcvoob: (flags & MSG_OOB) == 0"));
- m = m_get(M_WAIT, MT_DATA);
- error = (*pr->pr_usrreqs->pru_rcvoob)(so, m, flags & MSG_PEEK);
- if (error)
- goto bad;
- do {
- #ifdef ZERO_COPY_SOCKETS
- if (so_zero_copy_receive) {
- int disposable;
- if ((m->m_flags & M_EXT)
- && (m->m_ext.ext_type == EXT_DISPOSABLE))
- disposable = 1;
- else
- disposable = 0;
- error = uiomoveco(mtod(m, void *),
- min(uio->uio_resid, m->m_len),
- uio, disposable);
- } else
- #endif /* ZERO_COPY_SOCKETS */
- error = uiomove(mtod(m, void *),
- (int) min(uio->uio_resid, m->m_len), uio);
- m = m_free(m);
- } while (uio->uio_resid && error == 0 && m);
- bad:
- if (m != NULL)
- m_freem(m);
- return (error);
- }
- /*
- * Following replacement or removal of the first mbuf on the first mbuf chain
- * of a socket buffer, push necessary state changes back into the socket
- * buffer so that other consumers see the values consistently. 'nextrecord'
- * is the callers locally stored value of the original value of
- * sb->sb_mb->m_nextpkt which must be restored when the lead mbuf changes.
- * NOTE: 'nextrecord' may be NULL.
- */
- static __inline void
- sockbuf_pushsync(struct sockbuf *sb, struct mbuf *nextrecord)
- {
- SOCKBUF_LOCK_ASSERT(sb);
- /*
- * First, update for the new value of nextrecord. If necessary, make
- * it the first record.
- */
- if (sb->sb_mb != NULL)
- sb->sb_mb->m_nextpkt = nextrecord;
- else
- sb->sb_mb = nextrecord;
- /*
- * Now update any dependent socket buffer fields to reflect the new
- * state. This is an expanded inline of SB_EMPTY_FIXUP(), with the
- * addition of a second clause that takes care of the case where
- * sb_mb has been updated, but remains the last record.
- */
- if (sb->sb_mb == NULL) {
- sb->sb_mbtail = NULL;
- sb->sb_lastrecord = NULL;
- } else if (sb->sb_mb->m_nextpkt == NULL)
- sb->sb_lastrecord = sb->sb_mb;
- }
- /*
- * Implement receive operations on a socket. We depend on the way that
- * records are added to the sockbuf by sbappend. In particular, each record
- * (mbufs linked through m_next) must begin with an address if the protocol
- * so specifies, followed by an optional mbuf or mbufs containing ancillary
- * data, and then zero or more mbufs of data. In order to allow parallelism
- * between network receive and copying to user space, as well as avoid
- * sleeping with a mutex held, we release the socket buffer mutex during the
- * user space copy. Although the sockbuf is locked, new data may still be
- * appended, and thus we must maintain consistency of the sockbuf during that
- * time.
- *
- * The caller may receive the data as a single mbuf chain by supplying an
- * mbuf **mp0 for use in returning the chain. The uio is then used only for
- * the count in uio_resid.
- */
- int
- soreceive_generic(struct socket *so, struct sockaddr **psa, struct uio *uio,
- struct mbuf **mp0, struct mbuf **controlp, int *flagsp)
- {
- struct mbuf *m, **mp;
- int flags, len, error, offset;
- struct protosw *pr = so->so_proto;
- struct mbuf *nextrecord;
- int moff, type = 0;
- int orig_resid = uio->uio_resid;
- mp = mp0;
- if (psa != NULL)
- *psa = NULL;
- if (controlp != NULL)
- *controlp = NULL;
- if (flagsp != NULL)
- flags = *flagsp &~ MSG_EOR;
- else
- flags = 0;
- if (flags & MSG_OOB)
- return (soreceive_rcvoob(so, uio, flags));
- if (mp != NULL)
- *mp = NULL;
- if ((pr->pr_flags & PR_WANTRCVD) && (so->so_state & SS_ISCONFIRMING)
- && uio->uio_resid)
- (*pr->pr_usrreqs->pru_rcvd)(so, 0);
- error = sblock(&so->so_rcv, SBLOCKWAIT(flags));
- if (error)
- return (error);
- restart:
- SOCKBUF_LOCK(&so->so_rcv);
- m = so->so_rcv.sb_mb;
- /*
- * If we have less data than requested, block awaiting more (subject
- * to any timeout) if:
- * 1. the current count is less than the low water mark, or
- * 2. MSG_WAITALL is set, and it is possible to do the entire
- * receive operation at once if we block (resid <= hiwat).
- * 3. MSG_DONTWAIT is not set
- * If MSG_WAITALL is set but resid is larger than the receive buffer,
- * we have to do the receive in sections, and thus risk returning a
- * short count if a timeout or signal occurs after we start.
- */
- if (m == NULL || (((flags & MSG_DONTWAIT) == 0 &&
- so->so_rcv.sb_cc < uio->uio_resid) &&
- (so->so_rcv.sb_cc < so->so_rcv.sb_lowat ||
- ((flags & MSG_WAITALL) && uio->uio_resid <= so->so_rcv.sb_hiwat)) &&
- m->m_nextpkt == NULL && (pr->pr_flags & PR_ATOMIC) == 0)) {
- KASSERT(m != NULL || !so->so_rcv.sb_cc,
- ("receive: m == %p so->so_rcv.sb_cc == %u",
- m, so->so_rcv.sb_cc));
- if (so->so_error) {
- if (m != NULL)
- goto dontblock;
- error = so->so_error;
- if ((flags & MSG_PEEK) == 0)
- so->so_error = 0;
- SOCKBUF_UNLOCK(&so->so_rcv);
- goto release;
- }
- SOCKBUF_LOCK_ASSERT(&so->so_rcv);
- if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
- if (m == NULL) {
- SOCKBUF_UNLOCK(&so->so_rcv);
- goto release;
- } else
- goto dontblock;
- }
- for (; m != NULL; m = m->m_next)
- if (m->m_type == MT_OOBDATA || (m->m_flags & M_EOR)) {
- m = so->so_rcv.sb_mb;
- goto dontblock;
- }
- if ((so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING)) == 0 &&
- (so->so_proto->pr_flags & PR_CONNREQUIRED)) {
- SOCKBUF_UNLOCK(&so->so_rcv);
- error = ENOTCONN;
- goto release;
- }
- if (uio->uio_resid == 0) {
- SOCKBUF_UNLOCK(&so->so_rcv);
- goto release;
- }
- if ((so->so_state & SS_NBIO) ||
- (flags & (MSG_DONTWAIT|MSG_NBIO))) {
- SOCKBUF_UNLOCK(&so->so_rcv);
- error = EWOULDBLOCK;
- goto release;
- }
- SBLASTRECORDCHK(&so->so_rcv);
- SBLASTMBUFCHK(&so->so_rcv);
- error = sbwait(&so->so_rcv);
- SOCKBUF_UNLOCK(&so->so_rcv);
- if (error)
- goto release;
- goto restart;
- }
- dontblock:
- /*
- * From this point onward, we maintain 'nextrecord' as a cache of the
- * pointer to the next record in the socket buffer. We must keep the
- * various socket buffer pointers and local stack versions of the
- * pointers in sync, pushing out modifications before dropping the
- * socket buffer mutex, and re-reading them when picking it up.
- *
- * Otherwise, we will race with the network stack appending new data
- * or records onto the socket buffer by using inconsistent/stale
- * versions of the field, possibly resulting in socket buffer
- * corruption.
- *
- * By holding the high-level sblock(), we prevent simultaneous
- * readers from pulling off the front of the socket buffer.
- */
- SOCKBUF_LOCK_ASSERT(&so->so_rcv);
- if (uio->uio_td)
- uio->uio_td->td_ru.ru_msgrcv++;
- KASSERT(m == so->so_rcv.sb_mb, ("soreceive: m != so->so_rcv.sb_mb"));
- SBLASTRECORDCHK(&so->so_rcv);
- SBLASTMBUFCHK(&so->so_rcv);
- nextrecord = m->m_nextpkt;
- if (pr->pr_flags & PR_ADDR) {
- KASSERT(m->m_type == MT_SONAME,
- ("m->m_type == %d", m->m_type));
- orig_resid = 0;
- if (psa != NULL)
- *psa = sodupsockaddr(mtod(m, struct sockaddr *),
- M_NOWAIT);
- if (flags & MSG_PEEK) {
- m = m->m_next;
- } else {
- sbfree(&so->so_rcv, m);
- so->so_rcv.sb_mb = m_free(m);
- m = so->so_rcv.sb_mb;
- sockbuf_pushsync(&so->so_rcv, nextrecord);
- }
- }
- /*
- * Process one or more MT_CONTROL mbufs present before any data mbufs
- * in the first mbuf chain on the socket buffer. If MSG_PEEK, we
- * just copy the data; if !MSG_PEEK, we call into the protocol to
- * perform externalization (or freeing if controlp == NULL).
- */
- if (m != NULL && m->m_type == MT_CONTROL) {
- struct mbuf *cm = NULL, *cmn;
- struct mbuf **cme = &cm;
- do {
- if (flags & MSG_PEEK) {
- if (controlp != NULL) {
- *controlp = m_copy(m, 0, m->m_len);
- controlp = &(*controlp)->m_next;
- }
- m = m->m_next;
- } else {
- sbfree(&so->so_rcv, m);
- so->so_rcv.sb_mb = m->m_next;
- m->m_next = NULL;
- *cme = m;
- cme = &(*cme)->m_next;
- m = so->so_rcv.sb_mb;
- }
- } while (m != NULL && m->m_type == MT_CONTROL);
- if ((flags & MSG_PEEK) == 0)
- sockbuf_pushsync(&so->so_rcv, nextrecord);
- while (cm != NULL) {
- cmn = cm->m_next;
- cm->m_next = NULL;
- if (pr->pr_domain->dom_externalize != NULL) {
- SOCKBUF_UNLOCK(&so->so_rcv);
- error = (*pr->pr_domain->dom_externalize)
- (cm, controlp);
- SOCKBUF_LOCK(&so->so_rcv);
- } else if (controlp != NULL)
- *controlp = cm;
- else
- m_freem(cm);
- if (controlp != NULL) {
- orig_resid = 0;
- while (*controlp != NULL)
- controlp = &(*controlp)->m_next;
- }
- cm = cmn;
- }
- if (m != NULL)
- nextrecord = so->so_rcv.sb_mb->m_nextpkt;
- else
- nextrecord = so->so_rcv.sb_mb;
- orig_resid = 0;
- }
- if (m != NULL) {
- if ((flags & MSG_PEEK) == 0) {
- KASSERT(m->m_nextpkt == nextrecord,
- ("soreceive: post-control, nextrecord !sync"));
- if (nextrecord == NULL) {
- KASSERT(so->so_rcv.sb_mb == m,
- ("soreceive: post-control, sb_mb!=m"));
- KASSERT(so->so_rcv.sb_lastrecord == m,
- ("soreceive: post-control, lastrecord!=m"));
- }
- }
- type = m->m_type;
- if (type == MT_OOBDATA)
- flags |= MSG_OOB;
- } else {
- if ((flags & MSG_PEEK) == 0) {
- KASSERT(so->so_rcv.sb_mb == nextrecord,
- ("soreceive: sb_mb != nextrecord"));
- if (so->so_rcv.sb_mb == NULL) {
- KASSERT(so->so_rcv.sb_lastrecord == NULL,
- ("soreceive: sb_lastercord != NULL"));
- }
- }
- }
- SOCKBUF_LOCK_ASSERT(&so->so_rcv);
- SBLASTRECORDCHK(&so->so_rcv);
- SBLASTMBUFCHK(&so->so_rcv);
- /*
- * Now continue to read any data mbufs off of the head of the socket
- * buffer until the read request is satisfied. Note that 'type' is
- * used to store the type of any mbuf reads that have happened so far
- * such that soreceive() can stop reading if the type changes, which
- * causes soreceive() to return only one of regular data and inline
- * out-of-band data in a single socket receive operation.
- */
- moff = 0;
- offset = 0;
- while (m != NULL && uio->uio_resid > 0 && error == 0) {
- /*
- * If the type of mbuf has changed since the last mbuf
- * examined ('type'), end the receive operation.
- */
- SOCKBUF_LOCK_ASSERT(&so->so_rcv);
- if (m->m_type == MT_OOBDATA) {
- if (type != MT_OOBDATA)
- break;
- } else if (type == MT_OOBDATA)
- break;
- else
- KASSERT(m->m_type == MT_DATA,
- ("m->m_type == %d", m->m_type));
- so->so_rcv.sb_state &= ~SBS_RCVATMARK;
- len = uio->uio_resid;
- if (so->so_oobmark && len > so->so_oobmark - offset)
- len = so->so_oobmark - offset;
- if (len > m->m_len - moff)
- len = m->m_len - moff;
- /*
- * If mp is set, just pass back the mbufs. Otherwise copy
- * them out via the uio, then free. Sockbuf must be
- * consistent here (points to current mbuf, it points to next
- * record) when we drop priority; we must note any additions
- * to the sockbuf when we block interrupts again.
- */
- i…
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