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//==========================================================================

//

//      src/sys/kern/uipc_socket2.c

//

//==========================================================================

//####BSDCOPYRIGHTBEGIN####

//

// -------------------------------------------

//

// Portions of this software may have been derived from OpenBSD, 

// FreeBSD or other sources, and are covered by the appropriate

// copyright disclaimers included herein.

//

// Portions created by Red Hat are

// Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.

//

// -------------------------------------------

//

//####BSDCOPYRIGHTEND####

//==========================================================================

/*

 * 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

 * $FreeBSD: src/sys/kern/uipc_socket2.c,v 1.55.2.9 2001/07/26 18:53:02 peter Exp $

 */

#include <sys/param.h>

#include <sys/domain.h>

#include <sys/malloc.h>

#include <sys/mbuf.h>

#include <sys/protosw.h>

#include <sys/socket.h>

#include <sys/socketvar.h>

#include <cyg/io/file.h>

int     maxsockets = CYGPKG_NET_MAXSOCKETS;

/*

 * Primitive routines for operating on sockets and socket buffers

 */

u_long  sb_max = SB_MAX;                /* XXX should be static */

static  u_long sb_efficiency = 8;       /* parameter for sbreserve() */

/*

 * 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_incomp for connections in progress

 * and so_comp for connections already made and awaiting user acceptance.

 * As a protocol is preparing incoming connections, it creates a socket

 * structure queued on so_incomp by calling sonewconn().  When the connection

 * is established, soisconnected() is called, and transfers the

 * socket structure to so_comp, making it available to accept().

 *

 * If a socket is closed with sockets on either

 * so_incomp or so_comp, 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)

        struct socket *so;

{

        struct socket *head = so->so_head;

        so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING|SS_ISCONFIRMING);

        so->so_state |= SS_ISCONNECTED;

        if (head && (so->so_state & SS_INCOMP)) {

                if ((so->so_options & SO_ACCEPTFILTER) != 0) {

                        so->so_upcall = head->so_accf->so_accept_filter->accf_callback;

                        so->so_upcallarg = head->so_accf->so_accept_filter_arg;

                        so->so_rcv.sb_flags |= SB_UPCALL;

                        so->so_options &= ~SO_ACCEPTFILTER;

                        so->so_upcall(so, so->so_upcallarg, 0);

                        return;

                }

                TAILQ_REMOVE(&head->so_incomp, so, so_list);

                head->so_incqlen--;

                so->so_state &= ~SS_INCOMP;

                TAILQ_INSERT_TAIL(&head->so_comp, so, so_list);

                so->so_state |= SS_COMP;

                sorwakeup(head);

                wakeup_one(&head->so_timeo);

        } else {

                wakeup(&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|SS_ISDISCONNECTED);

        wakeup((caddr_t)&so->so_timeo);

        sowwakeup(so);

        sorwakeup(so);

}

/*

 * Return a random connection that hasn't been serviced yet and

 * is eligible for discard.  There is a one in qlen chance that

 * we will return a null, saying that there are no dropable

 * requests.  In this case, the protocol specific code should drop

 * the new request.  This insures fairness.

 *

 * This may be used in conjunction with protocol specific queue

 * congestion routines.

 */

struct socket *

sodropablereq(head)

        register struct socket *head;

{

        register struct socket *so;

        unsigned int i, j, qlen;

        static int rnd;

        static struct timeval old_runtime;

        static unsigned int cur_cnt, old_cnt;

        struct timeval tv;

        getmicrouptime(&tv);

        if ((i = (tv.tv_sec - old_runtime.tv_sec)) != 0) {

                old_runtime = tv;

                old_cnt = cur_cnt / i;

                cur_cnt = 0;

        }

        so = TAILQ_FIRST(&head->so_incomp);

        if (!so)

                return (so);

        qlen = head->so_incqlen;

        if (++cur_cnt > qlen || old_cnt > qlen) {

                rnd = (314159 * rnd + 66329) & 0xffff;

                j = ((qlen + 1) * rnd) >> 16;

                while (j-- && so)

                    so = TAILQ_NEXT(so, so_list);

        }

        return (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.

 */

struct socket *

sonewconn(head, connstatus)

        register struct socket *head;

        int connstatus;

{

        return (sonewconn3(head, connstatus, NULL));

}

struct socket *

sonewconn3(head, connstatus, p)

        register struct socket *head;

        int connstatus;

        struct proc *p;

{

        register struct socket *so;

        if (head->so_qlen > 3 * head->so_qlimit / 2)

                return ((struct socket *)0);

        so = soalloc(0);

        if (so == NULL)

                return ((struct socket *)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_proto = head->so_proto;

        so->so_timeo = head->so_timeo;

        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 ((struct socket *)0);

        }

        if (connstatus) {

                TAILQ_INSERT_TAIL(&head->so_comp, so, so_list);

                so->so_state |= SS_COMP;

        } else {

                TAILQ_INSERT_TAIL(&head->so_incomp, so, so_list);

                so->so_state |= SS_INCOMP;

                head->so_incqlen++;

        }

        head->so_qlen++;

        if (connstatus) {

                sorwakeup(head);

                wakeup((caddr_t)&head->so_timeo);

                so->so_state |= connstatus;

        }

        return (so);

}

/*

 * 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, "sbwait",

            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,

                    "sblock", 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;

{

        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 (sb->sb_flags & SB_UPCALL)

                (*so->so_upcall)(so, so->so_upcallarg, M_DONTWAIT);

}

/*

 * 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;

{

        struct proc *p = curproc;

        if (sbreserve(&so->so_snd, sndcc, so, p) == 0)

                goto bad;

        if (sbreserve(&so->so_rcv, rcvcc, so, p) == 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, so);

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, so, p)

        struct sockbuf *sb;

        u_long cc;

        struct socket *so;

        struct proc *p;

{

        /*

         * p will only be NULL when we're in an interrupt

         * (e.g. in tcp_input())

         */

        if ((u_quad_t)cc > (u_quad_t)sb_max * MCLBYTES / (MSIZE + MCLBYTES))

                return (0);

        sb->sb_hiwat = cc;

        sb->sb_mbmax = min(cc * sb_efficiency, 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, so)

        struct sockbuf *sb;

        struct socket *so;

{

        sbflush(sb);

        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 struct mbuf *n = 0;

        register u_long len = 0, mbcnt = 0;

        for (m = sb->sb_mb; m; m = n) {

            n = m->m_nextpkt;

            for (; m; m = m->m_next) {

                len += m->m_len;

                mbcnt += MSIZE;

                if (m->m_flags & M_EXT) /*XXX*/ /* pretty sure this is bogus */

                        mbcnt += m->m_ext.ext_size;

            }

        }

        if (len != sb->sb_cc || mbcnt != sb->sb_mbcnt) {

                printf("cc %ld != %ld || mbcnt %ld != %ld\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;