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freebsd/sys/kern/uipc_sockbuf.c
Garrett Wollman ff5c09da20 Make somaxconn (maximum backlog in a listen(2) request) and sb_max
(maximum size of a socket buffer) tunable.

Permit callers of listen(2) to specify a negative backlog, which
is translated into somaxconn.  Previously, a negative backlog was
silently translated into 0.
1995-11-03 18:33:46 +00:00

794 lines
20 KiB
C

/*
* Copyright (c) 1982, 1986, 1988, 1990, 1993
* The Regents of the University of California. 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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_socket2.c 8.1 (Berkeley) 6/10/93
* $Id: uipc_socket2.c,v 1.5 1995/05/30 08:06:22 rgrimes Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/buf.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/signalvar.h>
#include <sys/sysctl.h>
/*
* Primitive routines for operating on sockets and socket buffers
*/
/* strings for sleep message: */
char netio[] = "netio";
char netcon[] = "netcon";
char netcls[] = "netcls";
u_long sb_max = SB_MAX; /* XXX should be static */
SYSCTL_INT(_kern, KERN_MAXSOCKBUF, maxsockbuf, CTLFLAG_RW, &sb_max, 0, "")
/*
* Procedures to manipulate state flags of socket
* and do appropriate wakeups. Normal sequence from the
* active (originating) side is that soisconnecting() is
* called during processing of connect() call,
* resulting in an eventual call to soisconnected() if/when the
* connection is established. When the connection is torn down
* soisdisconnecting() is called during processing of disconnect() call,
* and soisdisconnected() is called when the connection to the peer
* is totally severed. The semantics of these routines are such that
* connectionless protocols can call soisconnected() and soisdisconnected()
* only, bypassing the in-progress calls when setting up a ``connection''
* takes no time.
*
* From the passive side, a socket is created with
* two queues of sockets: so_q0 for connections in progress
* and so_q for connections already made and awaiting user acceptance.
* As a protocol is preparing incoming connections, it creates a socket
* structure queued on so_q0 by calling sonewconn(). When the connection
* is established, soisconnected() is called, and transfers the
* socket structure to so_q, making it available to accept().
*
* If a socket is closed with sockets on either
* so_q0 or so_q, these sockets are dropped.
*
* If higher level protocols are implemented in
* the kernel, the wakeups done here will sometimes
* cause software-interrupt process scheduling.
*/
void
soisconnecting(so)
register struct socket *so;
{
so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING);
so->so_state |= SS_ISCONNECTING;
}
void
soisconnected(so)
register struct socket *so;
{
register struct socket *head = so->so_head;
so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING|SS_ISCONFIRMING);
so->so_state |= SS_ISCONNECTED;
if (head && soqremque(so, 0)) {
soqinsque(head, so, 1);
sorwakeup(head);
wakeup((caddr_t)&head->so_timeo);
} else {
wakeup((caddr_t)&so->so_timeo);
sorwakeup(so);
sowwakeup(so);
}
}
void
soisdisconnecting(so)
register struct socket *so;
{
so->so_state &= ~SS_ISCONNECTING;
so->so_state |= (SS_ISDISCONNECTING|SS_CANTRCVMORE|SS_CANTSENDMORE);
wakeup((caddr_t)&so->so_timeo);
sowwakeup(so);
sorwakeup(so);
}
void
soisdisconnected(so)
register struct socket *so;
{
so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING);
so->so_state |= (SS_CANTRCVMORE|SS_CANTSENDMORE);
wakeup((caddr_t)&so->so_timeo);
sowwakeup(so);
sorwakeup(so);
}
/*
* 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.
*
* Currently, sonewconn() is defined as sonewconn1() in socketvar.h
* to catch calls that are missing the (new) second parameter.
*/
struct socket *
sonewconn1(head, connstatus)
register struct socket *head;
int connstatus;
{
register struct socket *so;
int soqueue = connstatus ? 1 : 0;
if (head->so_qlen + head->so_q0len > 3 * head->so_qlimit / 2)
return ((struct socket *)0);
MALLOC(so, struct socket *, sizeof(*so), M_SOCKET, M_DONTWAIT);
if (so == NULL)
return ((struct socket *)0);
bzero((caddr_t)so, sizeof(*so));
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_proto = head->so_proto;
so->so_timeo = head->so_timeo;
so->so_pgid = head->so_pgid;
(void) soreserve(so, head->so_snd.sb_hiwat, head->so_rcv.sb_hiwat);
soqinsque(head, so, soqueue);
if ((*so->so_proto->pr_usrreq)(so, PRU_ATTACH,
(struct mbuf *)0, (struct mbuf *)0, (struct mbuf *)0)) {
(void) soqremque(so, soqueue);
(void) free((caddr_t)so, M_SOCKET);
return ((struct socket *)0);
}
if (connstatus) {
sorwakeup(head);
wakeup((caddr_t)&head->so_timeo);
so->so_state |= connstatus;
}
return (so);
}
void
soqinsque(head, so, q)
register struct socket *head, *so;
int q;
{
register struct socket **prev;
so->so_head = head;
if (q == 0) {
head->so_q0len++;
so->so_q0 = 0;
for (prev = &(head->so_q0); *prev; )
prev = &((*prev)->so_q0);
} else {
head->so_qlen++;
so->so_q = 0;
for (prev = &(head->so_q); *prev; )
prev = &((*prev)->so_q);
}
*prev = so;
}
int
soqremque(so, q)
register struct socket *so;
int q;
{
register struct socket *head, *prev, *next;
head = so->so_head;
prev = head;
for (;;) {
next = q ? prev->so_q : prev->so_q0;
if (next == so)
break;
if (next == 0)
return (0);
prev = next;
}
if (q == 0) {
prev->so_q0 = next->so_q0;
head->so_q0len--;
} else {
prev->so_q = next->so_q;
head->so_qlen--;
}
next->so_q0 = next->so_q = 0;
next->so_head = 0;
return (1);
}
/*
* Socantsendmore indicates that no more data will be sent on the
* socket; it would normally be applied to a socket when the user
* informs the system that no more data is to be sent, by the protocol
* code (in case PRU_SHUTDOWN). Socantrcvmore indicates that no more data
* will be received, and will normally be applied to the socket by a
* protocol when it detects that the peer will send no more data.
* Data queued for reading in the socket may yet be read.
*/
void
socantsendmore(so)
struct socket *so;
{
so->so_state |= SS_CANTSENDMORE;
sowwakeup(so);
}
void
socantrcvmore(so)
struct socket *so;
{
so->so_state |= SS_CANTRCVMORE;
sorwakeup(so);
}
/*
* Wait for data to arrive at/drain from a socket buffer.
*/
int
sbwait(sb)
struct sockbuf *sb;
{
sb->sb_flags |= SB_WAIT;
return (tsleep((caddr_t)&sb->sb_cc,
(sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK | PCATCH, netio,
sb->sb_timeo));
}
/*
* Lock a sockbuf already known to be locked;
* return any error returned from sleep (EINTR).
*/
int
sb_lock(sb)
register struct sockbuf *sb;
{
int error;
while (sb->sb_flags & SB_LOCK) {
sb->sb_flags |= SB_WANT;
error = tsleep((caddr_t)&sb->sb_flags,
(sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK|PCATCH,
netio, 0);
if (error)
return (error);
}
sb->sb_flags |= SB_LOCK;
return (0);
}
/*
* Wakeup processes waiting on a socket buffer.
* Do asynchronous notification via SIGIO
* if the socket has the SS_ASYNC flag set.
*/
void
sowakeup(so, sb)
register struct socket *so;
register struct sockbuf *sb;
{
struct proc *p;
selwakeup(&sb->sb_sel);
sb->sb_flags &= ~SB_SEL;
if (sb->sb_flags & SB_WAIT) {
sb->sb_flags &= ~SB_WAIT;
wakeup((caddr_t)&sb->sb_cc);
}
if (so->so_state & SS_ASYNC) {
if (so->so_pgid < 0)
gsignal(-so->so_pgid, SIGIO);
else if (so->so_pgid > 0 && (p = pfind(so->so_pgid)) != 0)
psignal(p, SIGIO);
}
}
/*
* Socket buffer (struct sockbuf) utility routines.
*
* Each socket contains two socket buffers: one for sending data and
* one for receiving data. Each buffer contains a queue of mbufs,
* information about the number of mbufs and amount of data in the
* queue, and other fields allowing select() statements and notification
* on data availability to be implemented.
*
* Data stored in a socket buffer is maintained as a list of records.
* Each record is a list of mbufs chained together with the m_next
* field. Records are chained together with the m_nextpkt field. The upper
* level routine soreceive() expects the following conventions to be
* observed when placing information in the receive buffer:
*
* 1. If the protocol requires each message be preceded by the sender's
* name, then a record containing that name must be present before
* any associated data (mbuf's must be of type MT_SONAME).
* 2. If the protocol supports the exchange of ``access rights'' (really
* just additional data associated with the message), and there are
* ``rights'' to be received, then a record containing this data
* should be present (mbuf's must be of type MT_RIGHTS).
* 3. If a name or rights record exists, then it must be followed by
* a data record, perhaps of zero length.
*
* Before using a new socket structure it is first necessary to reserve
* buffer space to the socket, by calling sbreserve(). This should commit
* some of the available buffer space in the system buffer pool for the
* socket (currently, it does nothing but enforce limits). The space
* should be released by calling sbrelease() when the socket is destroyed.
*/
int
soreserve(so, sndcc, rcvcc)
register struct socket *so;
u_long sndcc, rcvcc;
{
if (sbreserve(&so->so_snd, sndcc) == 0)
goto bad;
if (sbreserve(&so->so_rcv, rcvcc) == 0)
goto bad2;
if (so->so_rcv.sb_lowat == 0)
so->so_rcv.sb_lowat = 1;
if (so->so_snd.sb_lowat == 0)
so->so_snd.sb_lowat = MCLBYTES;
if (so->so_snd.sb_lowat > so->so_snd.sb_hiwat)
so->so_snd.sb_lowat = so->so_snd.sb_hiwat;
return (0);
bad2:
sbrelease(&so->so_snd);
bad:
return (ENOBUFS);
}
/*
* Allot mbufs to a sockbuf.
* Attempt to scale mbmax so that mbcnt doesn't become limiting
* if buffering efficiency is near the normal case.
*/
int
sbreserve(sb, cc)
struct sockbuf *sb;
u_long cc;
{
if (cc > sb_max * MCLBYTES / (MSIZE + MCLBYTES))
return (0);
sb->sb_hiwat = cc;
sb->sb_mbmax = min(cc * 2, sb_max);
if (sb->sb_lowat > sb->sb_hiwat)
sb->sb_lowat = sb->sb_hiwat;
return (1);
}
/*
* Free mbufs held by a socket, and reserved mbuf space.
*/
void
sbrelease(sb)
struct sockbuf *sb;
{
sbflush(sb);
sb->sb_hiwat = sb->sb_mbmax = 0;
}
/*
* Routines to add and remove
* data from an mbuf queue.
*
* The routines sbappend() or sbappendrecord() are normally called to
* append new mbufs to a socket buffer, after checking that adequate
* space is available, comparing the function sbspace() with the amount
* of data to be added. sbappendrecord() differs from sbappend() in
* that data supplied is treated as the beginning of a new record.
* To place a sender's address, optional access rights, and data in a
* socket receive buffer, sbappendaddr() should be used. To place
* access rights and data in a socket receive buffer, sbappendrights()
* should be used. In either case, the new data begins a new record.
* Note that unlike sbappend() and sbappendrecord(), these routines check
* for the caller that there will be enough space to store the data.
* Each fails if there is not enough space, or if it cannot find mbufs
* to store additional information in.
*
* Reliable protocols may use the socket send buffer to hold data
* awaiting acknowledgement. Data is normally copied from a socket
* send buffer in a protocol with m_copy for output to a peer,
* and then removing the data from the socket buffer with sbdrop()
* or sbdroprecord() when the data is acknowledged by the peer.
*/
/*
* Append mbuf chain m to the last record in the
* socket buffer sb. The additional space associated
* the mbuf chain is recorded in sb. Empty mbufs are
* discarded and mbufs are compacted where possible.
*/
void
sbappend(sb, m)
struct sockbuf *sb;
struct mbuf *m;
{
register struct mbuf *n;
if (m == 0)
return;
n = sb->sb_mb;
if (n) {
while (n->m_nextpkt)
n = n->m_nextpkt;
do {
if (n->m_flags & M_EOR) {
sbappendrecord(sb, m); /* XXXXXX!!!! */
return;
}
} while (n->m_next && (n = n->m_next));
}
sbcompress(sb, m, n);
}
#ifdef SOCKBUF_DEBUG
void
sbcheck(sb)
register struct sockbuf *sb;
{
register struct mbuf *m;
register int len = 0, mbcnt = 0;
for (m = sb->sb_mb; m; m = m->m_next) {
len += m->m_len;
mbcnt += MSIZE;
if (m->m_flags & M_EXT)
mbcnt += m->m_ext.ext_size;
if (m->m_nextpkt)
panic("sbcheck nextpkt");
}
if (len != sb->sb_cc || mbcnt != sb->sb_mbcnt) {
printf("cc %d != %d || mbcnt %d != %d\n", len, sb->sb_cc,
mbcnt, sb->sb_mbcnt);
panic("sbcheck");
}
}
#endif
/*
* As above, except the mbuf chain
* begins a new record.
*/
void
sbappendrecord(sb, m0)
register struct sockbuf *sb;
register struct mbuf *m0;
{
register struct mbuf *m;
if (m0 == 0)
return;
m = sb->sb_mb;
if (m)
while (m->m_nextpkt)
m = m->m_nextpkt;
/*
* Put the first mbuf on the queue.
* Note this permits zero length records.
*/
sballoc(sb, m0);
if (m)
m->m_nextpkt = m0;
else
sb->sb_mb = m0;
m = m0->m_next;
m0->m_next = 0;
if (m && (m0->m_flags & M_EOR)) {
m0->m_flags &= ~M_EOR;
m->m_flags |= M_EOR;
}
sbcompress(sb, m, m0);
}
/*
* As above except that OOB data
* is inserted at the beginning of the sockbuf,
* but after any other OOB data.
*/
void
sbinsertoob(sb, m0)
register struct sockbuf *sb;
register struct mbuf *m0;
{
register struct mbuf *m;
register struct mbuf **mp;
if (m0 == 0)
return;
for (mp = &sb->sb_mb; *mp ; mp = &((*mp)->m_nextpkt)) {
m = *mp;
again:
switch (m->m_type) {
case MT_OOBDATA:
continue; /* WANT next train */
case MT_CONTROL:
m = m->m_next;
if (m)
goto again; /* inspect THIS train further */
}
break;
}
/*
* Put the first mbuf on the queue.
* Note this permits zero length records.
*/
sballoc(sb, m0);
m0->m_nextpkt = *mp;
*mp = m0;
m = m0->m_next;
m0->m_next = 0;
if (m && (m0->m_flags & M_EOR)) {
m0->m_flags &= ~M_EOR;
m->m_flags |= M_EOR;
}
sbcompress(sb, m, m0);
}
/*
* Append address and data, and optionally, control (ancillary) data
* to the receive queue of a socket. If present,
* m0 must include a packet header with total length.
* Returns 0 if no space in sockbuf or insufficient mbufs.
*/
int
sbappendaddr(sb, asa, m0, control)
register struct sockbuf *sb;
struct sockaddr *asa;
struct mbuf *m0, *control;
{
register struct mbuf *m, *n;
int space = asa->sa_len;
if (m0 && (m0->m_flags & M_PKTHDR) == 0)
panic("sbappendaddr");
if (m0)
space += m0->m_pkthdr.len;
for (n = control; n; n = n->m_next) {
space += n->m_len;
if (n->m_next == 0) /* keep pointer to last control buf */
break;
}
if (space > sbspace(sb))
return (0);
if (asa->sa_len > MLEN)
return (0);
MGET(m, M_DONTWAIT, MT_SONAME);
if (m == 0)
return (0);
m->m_len = asa->sa_len;
bcopy((caddr_t)asa, mtod(m, caddr_t), asa->sa_len);
if (n)
n->m_next = m0; /* concatenate data to control */
else
control = m0;
m->m_next = control;
for (n = m; n; n = n->m_next)
sballoc(sb, n);
n = sb->sb_mb;
if (n) {
while (n->m_nextpkt)
n = n->m_nextpkt;
n->m_nextpkt = m;
} else
sb->sb_mb = m;
return (1);
}
int
sbappendcontrol(sb, m0, control)
struct sockbuf *sb;
struct mbuf *control, *m0;
{
register struct mbuf *m, *n;
int space = 0;
if (control == 0)
panic("sbappendcontrol");
for (m = control; ; m = m->m_next) {
space += m->m_len;
if (m->m_next == 0)
break;
}
n = m; /* save pointer to last control buffer */
for (m = m0; m; m = m->m_next)
space += m->m_len;
if (space > sbspace(sb))
return (0);
n->m_next = m0; /* concatenate data to control */
for (m = control; m; m = m->m_next)
sballoc(sb, m);
n = sb->sb_mb;
if (n) {
while (n->m_nextpkt)
n = n->m_nextpkt;
n->m_nextpkt = control;
} else
sb->sb_mb = control;
return (1);
}
/*
* Compress mbuf chain m into the socket
* buffer sb following mbuf n. If n
* is null, the buffer is presumed empty.
*/
void
sbcompress(sb, m, n)
register struct sockbuf *sb;
register struct mbuf *m, *n;
{
register int eor = 0;
register struct mbuf *o;
while (m) {
eor |= m->m_flags & M_EOR;
if (m->m_len == 0 &&
(eor == 0 ||
(((o = m->m_next) || (o = n)) &&
o->m_type == m->m_type))) {
m = m_free(m);
continue;
}
if (n && (n->m_flags & (M_EXT | M_EOR)) == 0 &&
(n->m_data + n->m_len + m->m_len) < &n->m_dat[MLEN] &&
n->m_type == m->m_type) {
bcopy(mtod(m, caddr_t), mtod(n, caddr_t) + n->m_len,
(unsigned)m->m_len);
n->m_len += m->m_len;
sb->sb_cc += m->m_len;
m = m_free(m);
continue;
}
if (n)
n->m_next = m;
else
sb->sb_mb = m;
sballoc(sb, m);
n = m;
m->m_flags &= ~M_EOR;
m = m->m_next;
n->m_next = 0;
}
if (eor) {
if (n)
n->m_flags |= eor;
else
printf("semi-panic: sbcompress\n");
}
}
/*
* Free all mbufs in a sockbuf.
* Check that all resources are reclaimed.
*/
void
sbflush(sb)
register struct sockbuf *sb;
{
if (sb->sb_flags & SB_LOCK)
panic("sbflush");
while (sb->sb_mbcnt)
sbdrop(sb, (int)sb->sb_cc);
if (sb->sb_cc || sb->sb_mb)
panic("sbflush 2");
}
/*
* Drop data from (the front of) a sockbuf.
*/
void
sbdrop(sb, len)
register struct sockbuf *sb;
register int len;
{
register struct mbuf *m, *mn;
struct mbuf *next;
next = (m = sb->sb_mb) ? m->m_nextpkt : 0;
while (len > 0) {
if (m == 0) {
if (next == 0)
panic("sbdrop");
m = next;
next = m->m_nextpkt;
continue;
}
if (m->m_len > len) {
m->m_len -= len;
m->m_data += len;
sb->sb_cc -= len;
break;
}
len -= m->m_len;
sbfree(sb, m);
MFREE(m, mn);
m = mn;
}
while (m && m->m_len == 0) {
sbfree(sb, m);
MFREE(m, mn);
m = mn;
}
if (m) {
sb->sb_mb = m;
m->m_nextpkt = next;
} else
sb->sb_mb = next;
}
/*
* Drop a record off the front of a sockbuf
* and move the next record to the front.
*/
void
sbdroprecord(sb)
register struct sockbuf *sb;
{
register struct mbuf *m, *mn;
m = sb->sb_mb;
if (m) {
sb->sb_mb = m->m_nextpkt;
do {
sbfree(sb, m);
MFREE(m, mn);
m = mn;
} while (m);
}
}