2 * Copyright (c) 1982, 1986, 1988, 1990, 1993
3 * The Regents of the University of California. All rights reserved.
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6 * modification, are permitted provided that the following conditions
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13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
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17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
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22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * @(#)uipc_socket2.c 8.1 (Berkeley) 6/10/93
34 * $FreeBSD: src/sys/kern/uipc_socket2.c,v 1.55.2.17 2002/08/31 19:04:55 dwmalone Exp $
35 * $DragonFly: src/sys/kern/uipc_socket2.c,v 1.5 2003/07/26 19:42:11 rob Exp $
38 #include "opt_param.h"
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/domain.h>
42 #include <sys/file.h> /* for maxfiles */
43 #include <sys/kernel.h>
45 #include <sys/malloc.h>
47 #include <sys/protosw.h>
48 #include <sys/resourcevar.h>
50 #include <sys/socket.h>
51 #include <sys/socketvar.h>
52 #include <sys/signalvar.h>
53 #include <sys/sysctl.h>
54 #include <sys/aio.h> /* for aio_swake proto */
55 #include <sys/event.h>
60 * Primitive routines for operating on sockets and socket buffers
63 u_long sb_max = SB_MAX;
65 SB_MAX * MCLBYTES / (MSIZE + MCLBYTES); /* adjusted sb_max */
67 static u_long sb_efficiency = 8; /* parameter for sbreserve() */
70 * Procedures to manipulate state flags of socket
71 * and do appropriate wakeups. Normal sequence from the
72 * active (originating) side is that soisconnecting() is
73 * called during processing of connect() call,
74 * resulting in an eventual call to soisconnected() if/when the
75 * connection is established. When the connection is torn down
76 * soisdisconnecting() is called during processing of disconnect() call,
77 * and soisdisconnected() is called when the connection to the peer
78 * is totally severed. The semantics of these routines are such that
79 * connectionless protocols can call soisconnected() and soisdisconnected()
80 * only, bypassing the in-progress calls when setting up a ``connection''
83 * From the passive side, a socket is created with
84 * two queues of sockets: so_incomp for connections in progress
85 * and so_comp for connections already made and awaiting user acceptance.
86 * As a protocol is preparing incoming connections, it creates a socket
87 * structure queued on so_incomp by calling sonewconn(). When the connection
88 * is established, soisconnected() is called, and transfers the
89 * socket structure to so_comp, making it available to accept().
91 * If a socket is closed with sockets on either
92 * so_incomp or so_comp, these sockets are dropped.
94 * If higher level protocols are implemented in
95 * the kernel, the wakeups done here will sometimes
96 * cause software-interrupt process scheduling.
104 so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING);
105 so->so_state |= SS_ISCONNECTING;
112 struct socket *head = so->so_head;
114 so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING|SS_ISCONFIRMING);
115 so->so_state |= SS_ISCONNECTED;
116 if (head && (so->so_state & SS_INCOMP)) {
117 if ((so->so_options & SO_ACCEPTFILTER) != 0) {
118 so->so_upcall = head->so_accf->so_accept_filter->accf_callback;
119 so->so_upcallarg = head->so_accf->so_accept_filter_arg;
120 so->so_rcv.sb_flags |= SB_UPCALL;
121 so->so_options &= ~SO_ACCEPTFILTER;
122 so->so_upcall(so, so->so_upcallarg, 0);
125 TAILQ_REMOVE(&head->so_incomp, so, so_list);
127 so->so_state &= ~SS_INCOMP;
128 TAILQ_INSERT_TAIL(&head->so_comp, so, so_list);
130 so->so_state |= SS_COMP;
132 wakeup_one(&head->so_timeo);
134 wakeup(&so->so_timeo);
141 soisdisconnecting(so)
145 so->so_state &= ~SS_ISCONNECTING;
146 so->so_state |= (SS_ISDISCONNECTING|SS_CANTRCVMORE|SS_CANTSENDMORE);
147 wakeup((caddr_t)&so->so_timeo);
157 so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING);
158 so->so_state |= (SS_CANTRCVMORE|SS_CANTSENDMORE|SS_ISDISCONNECTED);
159 wakeup((caddr_t)&so->so_timeo);
160 sbdrop(&so->so_snd, so->so_snd.sb_cc);
166 * When an attempt at a new connection is noted on a socket
167 * which accepts connections, sonewconn is called. If the
168 * connection is possible (subject to space constraints, etc.)
169 * then we allocate a new structure, propoerly linked into the
170 * data structure of the original socket, and return this.
171 * Connstatus may be 0, or SO_ISCONFIRMING, or SO_ISCONNECTED.
174 sonewconn(struct socket *head, int connstatus)
178 if (head->so_qlen > 3 * head->so_qlimit / 2)
179 return ((struct socket *)0);
182 return ((struct socket *)0);
183 if ((head->so_options & SO_ACCEPTFILTER) != 0)
186 so->so_type = head->so_type;
187 so->so_options = head->so_options &~ SO_ACCEPTCONN;
188 so->so_linger = head->so_linger;
189 so->so_state = head->so_state | SS_NOFDREF;
190 so->so_proto = head->so_proto;
191 so->so_timeo = head->so_timeo;
192 so->so_cred = crhold(head->so_cred);
193 if (soreserve(so, head->so_snd.sb_hiwat, head->so_rcv.sb_hiwat) ||
194 (*so->so_proto->pr_usrreqs->pru_attach)(so, 0, NULL)) {
196 return ((struct socket *)0);
200 TAILQ_INSERT_TAIL(&head->so_comp, so, so_list);
201 so->so_state |= SS_COMP;
204 if (head->so_incqlen > head->so_qlimit) {
206 sp = TAILQ_FIRST(&head->so_incomp);
209 TAILQ_INSERT_TAIL(&head->so_incomp, so, so_list);
210 so->so_state |= SS_INCOMP;
215 wakeup((caddr_t)&head->so_timeo);
216 so->so_state |= connstatus;
222 * Socantsendmore indicates that no more data will be sent on the
223 * socket; it would normally be applied to a socket when the user
224 * informs the system that no more data is to be sent, by the protocol
225 * code (in case PRU_SHUTDOWN). Socantrcvmore indicates that no more data
226 * will be received, and will normally be applied to the socket by a
227 * protocol when it detects that the peer will send no more data.
228 * Data queued for reading in the socket may yet be read.
236 so->so_state |= SS_CANTSENDMORE;
245 so->so_state |= SS_CANTRCVMORE;
250 * Wait for data to arrive at/drain from a socket buffer.
257 sb->sb_flags |= SB_WAIT;
258 return (tsleep((caddr_t)&sb->sb_cc,
259 ((sb->sb_flags & SB_NOINTR) ? 0 : PCATCH),
265 * Lock a sockbuf already known to be locked;
266 * return any error returned from sleep (EINTR).
274 while (sb->sb_flags & SB_LOCK) {
275 sb->sb_flags |= SB_WANT;
276 error = tsleep((caddr_t)&sb->sb_flags,
277 ((sb->sb_flags & SB_NOINTR) ? 0 : PCATCH),
282 sb->sb_flags |= SB_LOCK;
287 * Wakeup processes waiting on a socket buffer.
288 * Do asynchronous notification via SIGIO
289 * if the socket has the SS_ASYNC flag set.
296 selwakeup(&sb->sb_sel);
297 sb->sb_flags &= ~SB_SEL;
298 if (sb->sb_flags & SB_WAIT) {
299 sb->sb_flags &= ~SB_WAIT;
300 wakeup((caddr_t)&sb->sb_cc);
302 if ((so->so_state & SS_ASYNC) && so->so_sigio != NULL)
303 pgsigio(so->so_sigio, SIGIO, 0);
304 if (sb->sb_flags & SB_UPCALL)
305 (*so->so_upcall)(so, so->so_upcallarg, M_DONTWAIT);
306 if (sb->sb_flags & SB_AIO)
308 KNOTE(&sb->sb_sel.si_note, 0);
312 * Socket buffer (struct sockbuf) utility routines.
314 * Each socket contains two socket buffers: one for sending data and
315 * one for receiving data. Each buffer contains a queue of mbufs,
316 * information about the number of mbufs and amount of data in the
317 * queue, and other fields allowing select() statements and notification
318 * on data availability to be implemented.
320 * Data stored in a socket buffer is maintained as a list of records.
321 * Each record is a list of mbufs chained together with the m_next
322 * field. Records are chained together with the m_nextpkt field. The upper
323 * level routine soreceive() expects the following conventions to be
324 * observed when placing information in the receive buffer:
326 * 1. If the protocol requires each message be preceded by the sender's
327 * name, then a record containing that name must be present before
328 * any associated data (mbuf's must be of type MT_SONAME).
329 * 2. If the protocol supports the exchange of ``access rights'' (really
330 * just additional data associated with the message), and there are
331 * ``rights'' to be received, then a record containing this data
332 * should be present (mbuf's must be of type MT_RIGHTS).
333 * 3. If a name or rights record exists, then it must be followed by
334 * a data record, perhaps of zero length.
336 * Before using a new socket structure it is first necessary to reserve
337 * buffer space to the socket, by calling sbreserve(). This should commit
338 * some of the available buffer space in the system buffer pool for the
339 * socket (currently, it does nothing but enforce limits). The space
340 * should be released by calling sbrelease() when the socket is destroyed.
344 soreserve(so, sndcc, rcvcc)
348 struct proc *p = curproc;
350 if (sbreserve(&so->so_snd, sndcc, so, p) == 0)
352 if (sbreserve(&so->so_rcv, rcvcc, so, p) == 0)
354 if (so->so_rcv.sb_lowat == 0)
355 so->so_rcv.sb_lowat = 1;
356 if (so->so_snd.sb_lowat == 0)
357 so->so_snd.sb_lowat = MCLBYTES;
358 if (so->so_snd.sb_lowat > so->so_snd.sb_hiwat)
359 so->so_snd.sb_lowat = so->so_snd.sb_hiwat;
362 sbrelease(&so->so_snd, so);
368 sysctl_handle_sb_max(SYSCTL_HANDLER_ARGS)
371 u_long old_sb_max = sb_max;
373 error = SYSCTL_OUT(req, arg1, sizeof(int));
374 if (error || !req->newptr)
376 error = SYSCTL_IN(req, arg1, sizeof(int));
379 if (sb_max < MSIZE + MCLBYTES) {
383 sb_max_adj = (u_quad_t)sb_max * MCLBYTES / (MSIZE + MCLBYTES);
388 * Allot mbufs to a sockbuf.
389 * Attempt to scale mbmax so that mbcnt doesn't become limiting
390 * if buffering efficiency is near the normal case.
393 sbreserve(sb, cc, so, p)
401 * p will only be NULL when we're in an interrupt
402 * (e.g. in tcp_input())
406 if (!chgsbsize(so->so_cred->cr_uidinfo, &sb->sb_hiwat, cc,
407 p ? p->p_rlimit[RLIMIT_SBSIZE].rlim_cur : RLIM_INFINITY)) {
410 sb->sb_mbmax = min(cc * sb_efficiency, sb_max);
411 if (sb->sb_lowat > sb->sb_hiwat)
412 sb->sb_lowat = sb->sb_hiwat;
417 * Free mbufs held by a socket, and reserved mbuf space.
426 (void)chgsbsize(so->so_cred->cr_uidinfo, &sb->sb_hiwat, 0,
432 * Routines to add and remove
433 * data from an mbuf queue.
435 * The routines sbappend() or sbappendrecord() are normally called to
436 * append new mbufs to a socket buffer, after checking that adequate
437 * space is available, comparing the function sbspace() with the amount
438 * of data to be added. sbappendrecord() differs from sbappend() in
439 * that data supplied is treated as the beginning of a new record.
440 * To place a sender's address, optional access rights, and data in a
441 * socket receive buffer, sbappendaddr() should be used. To place
442 * access rights and data in a socket receive buffer, sbappendrights()
443 * should be used. In either case, the new data begins a new record.
444 * Note that unlike sbappend() and sbappendrecord(), these routines check
445 * for the caller that there will be enough space to store the data.
446 * Each fails if there is not enough space, or if it cannot find mbufs
447 * to store additional information in.
449 * Reliable protocols may use the socket send buffer to hold data
450 * awaiting acknowledgement. Data is normally copied from a socket
451 * send buffer in a protocol with m_copy for output to a peer,
452 * and then removing the data from the socket buffer with sbdrop()
453 * or sbdroprecord() when the data is acknowledged by the peer.
457 * Append mbuf chain m to the last record in the
458 * socket buffer sb. The additional space associated
459 * the mbuf chain is recorded in sb. Empty mbufs are
460 * discarded and mbufs are compacted where possible.
476 if (n->m_flags & M_EOR) {
477 sbappendrecord(sb, m); /* XXXXXX!!!! */
480 } while (n->m_next && (n = n->m_next));
482 sbcompress(sb, m, n);
492 u_long len = 0, mbcnt = 0;
494 for (m = sb->sb_mb; m; m = n) {
496 for (; m; m = m->m_next) {
499 if (m->m_flags & M_EXT) /*XXX*/ /* pretty sure this is bogus */
500 mbcnt += m->m_ext.ext_size;
503 if (len != sb->sb_cc || mbcnt != sb->sb_mbcnt) {
504 printf("cc %ld != %ld || mbcnt %ld != %ld\n", len, sb->sb_cc,
505 mbcnt, sb->sb_mbcnt);
512 * As above, except the mbuf chain
513 * begins a new record.
516 sbappendrecord(sb, m0)
529 * Put the first mbuf on the queue.
530 * Note this permits zero length records.
539 if (m && (m0->m_flags & M_EOR)) {
540 m0->m_flags &= ~M_EOR;
543 sbcompress(sb, m, m0);
547 * As above except that OOB data
548 * is inserted at the beginning of the sockbuf,
549 * but after any other OOB data.
561 for (mp = &sb->sb_mb; *mp ; mp = &((*mp)->m_nextpkt)) {
567 continue; /* WANT next train */
572 goto again; /* inspect THIS train further */
577 * Put the first mbuf on the queue.
578 * Note this permits zero length records.
585 if (m && (m0->m_flags & M_EOR)) {
586 m0->m_flags &= ~M_EOR;
589 sbcompress(sb, m, m0);
593 * Append address and data, and optionally, control (ancillary) data
594 * to the receive queue of a socket. If present,
595 * m0 must include a packet header with total length.
596 * Returns 0 if no space in sockbuf or insufficient mbufs.
599 sbappendaddr(sb, asa, m0, control)
601 struct sockaddr *asa;
602 struct mbuf *m0, *control;
605 int space = asa->sa_len;
607 if (m0 && (m0->m_flags & M_PKTHDR) == 0)
608 panic("sbappendaddr");
610 space += m0->m_pkthdr.len;
611 for (n = control; n; n = n->m_next) {
613 if (n->m_next == 0) /* keep pointer to last control buf */
616 if (space > sbspace(sb))
618 if (asa->sa_len > MLEN)
620 MGET(m, M_DONTWAIT, MT_SONAME);
623 m->m_len = asa->sa_len;
624 bcopy((caddr_t)asa, mtod(m, caddr_t), asa->sa_len);
626 n->m_next = m0; /* concatenate data to control */
630 for (n = m; n; n = n->m_next)
643 sbappendcontrol(sb, m0, control)
645 struct mbuf *control, *m0;
651 panic("sbappendcontrol");
652 for (m = control; ; m = m->m_next) {
657 n = m; /* save pointer to last control buffer */
658 for (m = m0; m; m = m->m_next)
660 if (space > sbspace(sb))
662 n->m_next = m0; /* concatenate data to control */
663 for (m = control; m; m = m->m_next)
669 n->m_nextpkt = control;
676 * Compress mbuf chain m into the socket
677 * buffer sb following mbuf n. If n
678 * is null, the buffer is presumed empty.
689 eor |= m->m_flags & M_EOR;
692 (((o = m->m_next) || (o = n)) &&
693 o->m_type == m->m_type))) {
697 if (n && (n->m_flags & M_EOR) == 0 &&
699 m->m_len <= MCLBYTES / 4 && /* XXX: Don't copy too much */
700 m->m_len <= M_TRAILINGSPACE(n) &&
701 n->m_type == m->m_type) {
702 bcopy(mtod(m, caddr_t), mtod(n, caddr_t) + n->m_len,
704 n->m_len += m->m_len;
705 sb->sb_cc += m->m_len;
715 m->m_flags &= ~M_EOR;
723 printf("semi-panic: sbcompress\n");
728 * Free all mbufs in a sockbuf.
729 * Check that all resources are reclaimed.
736 if (sb->sb_flags & SB_LOCK)
737 panic("sbflush: locked");
738 while (sb->sb_mbcnt) {
740 * Don't call sbdrop(sb, 0) if the leading mbuf is non-empty:
741 * we would loop forever. Panic instead.
743 if (!sb->sb_cc && (sb->sb_mb == NULL || sb->sb_mb->m_len))
745 sbdrop(sb, (int)sb->sb_cc);
747 if (sb->sb_cc || sb->sb_mb || sb->sb_mbcnt)
748 panic("sbflush: cc %ld || mb %p || mbcnt %ld", sb->sb_cc, (void *)sb->sb_mb, sb->sb_mbcnt);
752 * Drop data from (the front of) a sockbuf.
762 next = (m = sb->sb_mb) ? m->m_nextpkt : 0;
771 if (m->m_len > len) {
781 while (m && m->m_len == 0) {
793 * Drop a record off the front of a sockbuf
794 * and move the next record to the front.
804 sb->sb_mb = m->m_nextpkt;
813 * Create a "control" mbuf containing the specified data
814 * with the specified type for presentation on a socket buffer.
817 sbcreatecontrol(p, size, type, level)
825 if (CMSG_SPACE((u_int)size) > MCLBYTES)
826 return ((struct mbuf *) NULL);
827 if ((m = m_get(M_DONTWAIT, MT_CONTROL)) == NULL)
828 return ((struct mbuf *) NULL);
829 if (CMSG_SPACE((u_int)size) > MLEN) {
830 MCLGET(m, M_DONTWAIT);
831 if ((m->m_flags & M_EXT) == 0) {
833 return ((struct mbuf *) NULL);
836 cp = mtod(m, struct cmsghdr *);
838 KASSERT(CMSG_SPACE((u_int)size) <= M_TRAILINGSPACE(m),
839 ("sbcreatecontrol: short mbuf"));
841 (void)memcpy(CMSG_DATA(cp), p, size);
842 m->m_len = CMSG_SPACE(size);
843 cp->cmsg_len = CMSG_LEN(size);
844 cp->cmsg_level = level;
845 cp->cmsg_type = type;
850 * Some routines that return EOPNOTSUPP for entry points that are not
851 * supported by a protocol. Fill in as needed.
854 pru_accept_notsupp(struct socket *so, struct sockaddr **nam)
860 pru_connect_notsupp(struct socket *so, struct sockaddr *nam, struct thread *td)
866 pru_connect2_notsupp(struct socket *so1, struct socket *so2)
872 pru_control_notsupp(struct socket *so, u_long cmd, caddr_t data,
873 struct ifnet *ifp, struct thread *td)
879 pru_listen_notsupp(struct socket *so, struct thread *td)
885 pru_rcvd_notsupp(struct socket *so, int flags)
891 pru_rcvoob_notsupp(struct socket *so, struct mbuf *m, int flags)
897 * This isn't really a ``null'' operation, but it's the default one
898 * and doesn't do anything destructive.
901 pru_sense_null(struct socket *so, struct stat *sb)
903 sb->st_blksize = so->so_snd.sb_hiwat;
908 * Make a copy of a sockaddr in a malloced buffer of type M_SONAME.
911 dup_sockaddr(sa, canwait)
915 struct sockaddr *sa2;
917 MALLOC(sa2, struct sockaddr *, sa->sa_len, M_SONAME,
918 canwait ? M_WAITOK : M_NOWAIT);
920 bcopy(sa, sa2, sa->sa_len);
925 * Create an external-format (``xsocket'') structure using the information
926 * in the kernel-format socket structure pointed to by so. This is done
927 * to reduce the spew of irrelevant information over this interface,
928 * to isolate user code from changes in the kernel structure, and
929 * potentially to provide information-hiding if we decide that
930 * some of this information should be hidden from users.
933 sotoxsocket(struct socket *so, struct xsocket *xso)
935 xso->xso_len = sizeof *xso;
937 xso->so_type = so->so_type;
938 xso->so_options = so->so_options;
939 xso->so_linger = so->so_linger;
940 xso->so_state = so->so_state;
941 xso->so_pcb = so->so_pcb;
942 xso->xso_protocol = so->so_proto->pr_protocol;
943 xso->xso_family = so->so_proto->pr_domain->dom_family;
944 xso->so_qlen = so->so_qlen;
945 xso->so_incqlen = so->so_incqlen;
946 xso->so_qlimit = so->so_qlimit;
947 xso->so_timeo = so->so_timeo;
948 xso->so_error = so->so_error;
949 xso->so_pgid = so->so_sigio ? so->so_sigio->sio_pgid : 0;
950 xso->so_oobmark = so->so_oobmark;
951 sbtoxsockbuf(&so->so_snd, &xso->so_snd);
952 sbtoxsockbuf(&so->so_rcv, &xso->so_rcv);
953 xso->so_uid = so->so_cred->cr_uid;
957 * This does the same for sockbufs. Note that the xsockbuf structure,
958 * since it is always embedded in a socket, does not include a self
959 * pointer nor a length. We make this entry point public in case
960 * some other mechanism needs it.
963 sbtoxsockbuf(struct sockbuf *sb, struct xsockbuf *xsb)
965 xsb->sb_cc = sb->sb_cc;
966 xsb->sb_hiwat = sb->sb_hiwat;
967 xsb->sb_mbcnt = sb->sb_mbcnt;
968 xsb->sb_mbmax = sb->sb_mbmax;
969 xsb->sb_lowat = sb->sb_lowat;
970 xsb->sb_flags = sb->sb_flags;
971 xsb->sb_timeo = sb->sb_timeo;
975 * Here is the definition of some of the basic objects in the kern.ipc
978 SYSCTL_NODE(_kern, KERN_IPC, ipc, CTLFLAG_RW, 0, "IPC");
980 /* This takes the place of kern.maxsockbuf, which moved to kern.ipc. */
982 SYSCTL_INT(_kern, KERN_DUMMY, dummy, CTLFLAG_RW, &dummy, 0, "");
983 SYSCTL_OID(_kern_ipc, KIPC_MAXSOCKBUF, maxsockbuf, CTLTYPE_INT|CTLFLAG_RW,
984 &sb_max, 0, sysctl_handle_sb_max, "I", "Maximum socket buffer size");
985 SYSCTL_INT(_kern_ipc, OID_AUTO, maxsockets, CTLFLAG_RD,
986 &maxsockets, 0, "Maximum number of sockets avaliable");
987 SYSCTL_INT(_kern_ipc, KIPC_SOCKBUF_WASTE, sockbuf_waste_factor, CTLFLAG_RW,
988 &sb_efficiency, 0, "");
991 * Initialise maxsockets
993 static void init_maxsockets(void *ignored)
995 TUNABLE_INT_FETCH("kern.ipc.maxsockets", &maxsockets);
996 maxsockets = imax(maxsockets, imax(maxfiles, nmbclusters));
998 SYSINIT(param, SI_SUB_TUNABLES, SI_ORDER_ANY, init_maxsockets, NULL);