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

//

//      src/sys/kern/uipc_mbuf2.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####

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

/*      $KAME: uipc_mbuf2.c,v 1.31 2001/11/28 11:08:53 itojun Exp $     */

/*      $NetBSD: uipc_mbuf.c,v 1.40 1999/04/01 00:23:25 thorpej Exp $   */

/*

 * Copyright (C) 1999 WIDE Project.

 * 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. Neither the name of the project 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 PROJECT 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 PROJECT 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.

 */

/*

 * Copyright (c) 1982, 1986, 1988, 1991, 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_mbuf.c 8.4 (Berkeley) 2/14/95

 */

#include <sys/param.h>

#include <sys/malloc.h>

#include <sys/mbuf.h>

#ifdef __bsdi__

#define M_SHAREDCLUSTER(m) \

        (((m)->m_flags & M_EXT) != 0 && \

         ((m)->m_ext.ext_func || mclrefcnt[mtocl((m)->m_ext.ext_buf)] > 1))

#elif defined(__NetBSD__) || defined(__OpenBSD__)

#define M_SHAREDCLUSTER(m) \

        (((m)->m_flags & M_EXT) != 0 && \

         ((m)->m_ext.ext_free || MCLISREFERENCED((m))))

#else

#define M_SHAREDCLUSTER(m) \

        (((m)->m_flags & M_EXT) != 0 && \

         ((m)->m_ext.ext_free || mclrefcnt[mtocl((m)->m_ext.ext_buf)] > 1))

#endif

#ifndef __NetBSD__

/* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */

static struct mbuf *m_dup1 __P((struct mbuf *, int, int, int));

#endif

/*

 * ensure that [off, off + len) is contiguous on the mbuf chain "m".

 * packet chain before "off" is kept untouched.

 * if offp == NULL, the target will start at <retval, 0> on resulting chain.

 * if offp != NULL, the target will start at <retval, *offp> on resulting chain.

 *

 * on error return (NULL return value), original "m" will be freed.

 *

 * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster)

 */

struct mbuf *

m_pulldown(m, off, len, offp)

        struct mbuf *m;

        int off, len;

        int *offp;

{

        struct mbuf *n, *o;

        int hlen, tlen, olen;

        int sharedcluster;

#ifdef PULLDOWN_STAT

        static struct mbuf *prev = NULL;

        int prevlen = 0, prevmlen = 0;

#endif

        /* check invalid arguments. */

        if (m == NULL)

                panic("m == NULL in m_pulldown()");

        if (len > MCLBYTES) {

                m_freem(m);

                return NULL;    /* impossible */

        }

#ifdef PULLDOWN_STAT

        mbstat.m_pulldowns++;

#endif

#ifdef PULLDOWN_STAT

        /* statistics for m_pullup */

        mbstat.m_pullups++;

        if (off + len > MHLEN)

                mbstat.m_pullup_fail++;

        else {

                int dlen, mlen;

                dlen = (prev == m) ? prevlen : m->m_len;

                mlen = (prev == m) ? prevmlen : m->m_len + M_TRAILINGSPACE(m);

                if (dlen >= off + len)

                        mbstat.m_pullups--; /* call will not be made! */

                else if ((m->m_flags & M_EXT) != 0) {

                        mbstat.m_pullup_alloc++;

                        mbstat.m_pullup_copy++;

                } else {

                        if (mlen >= off + len)

                                mbstat.m_pullup_copy++;

                        else {

                                mbstat.m_pullup_alloc++;

                                mbstat.m_pullup_copy++;

                        }

                }

                prevlen = off + len;

                prevmlen = MHLEN;

        }

        /* statistics for m_pullup2 */

        mbstat.m_pullup2++;

        if (off + len > MCLBYTES)

                mbstat.m_pullup2_fail++;

        else {

                int dlen, mlen;

                dlen = (prev == m) ? prevlen : m->m_len;

                mlen = (prev == m) ? prevmlen : m->m_len + M_TRAILINGSPACE(m);

                prevlen = off + len;

                prevmlen = mlen;

                if (dlen >= off + len)

                        mbstat.m_pullup2--; /* call will not be made! */

                else if ((m->m_flags & M_EXT) != 0) {

                        mbstat.m_pullup2_alloc++;

                        mbstat.m_pullup2_copy++;

                        prevmlen = (off + len > MHLEN) ? MCLBYTES : MHLEN;

                } else {

                        if (mlen >= off + len)

                                mbstat.m_pullup2_copy++;

                        else {

                                mbstat.m_pullup2_alloc++;

                                mbstat.m_pullup2_copy++;

                                prevmlen = (off + len > MHLEN) ? MCLBYTES

                                                               : MHLEN;

                        }

                }

        }

        prev = m;

#endif

#ifdef PULLDOWN_DEBUG

    {

        struct mbuf *t;

        printf("before:");

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

                printf(" %d", t->m_len);

        printf("\n");

    }

#endif

        n = m;

        while (n != NULL && off > 0) {

                if (n->m_len > off)

                        break;

                off -= n->m_len;

                n = n->m_next;

        }

        /* be sure to point non-empty mbuf */

        while (n != NULL && n->m_len == 0)

                n = n->m_next;

        if (!n) {

                m_freem(m);

                return NULL;    /* mbuf chain too short */

        }

        sharedcluster = M_SHAREDCLUSTER(n);

        /*

         * the target data is on <n, off>.

         * if we got enough data on the mbuf "n", we're done.

         */

        if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster)

                goto ok;

#ifdef PULLDOWN_STAT

        mbstat.m_pulldown_copy++;

#endif

        /*

         * when len <= n->m_len - off and off != 0, it is a special case.

         * len bytes from <n, off> sits in single mbuf, but the caller does

         * not like the starting position (off).

         * chop the current mbuf into two pieces, set off to 0.

         */

        if (len <= n->m_len - off) {

#ifdef __NetBSD__

                o = m_dup(n, off, n->m_len - off, M_DONTWAIT);

#else

                o = m_dup1(n, off, n->m_len - off, M_DONTWAIT);

#endif

                if (o == NULL) {

                        m_freem(m);

                        return NULL;    /* ENOBUFS */

                }

                n->m_len = off;

                o->m_next = n->m_next;

                n->m_next = o;

                n = n->m_next;

                off = 0;

                goto ok;

        }

        /*

         * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,

         * and construct contiguous mbuf with m_len == len.

         * note that hlen + tlen == len, and tlen > 0.

         */

        hlen = n->m_len - off;

        tlen = len - hlen;

        /*

         * ensure that we have enough trailing data on mbuf chain.

         * if not, we can do nothing about the chain.

         */

        olen = 0;

        for (o = n->m_next; o != NULL; o = o->m_next)

                olen += o->m_len;

        if (hlen + olen < len) {

                m_freem(m);

                return NULL;    /* mbuf chain too short */

        }

        /*

         * easy cases first.

         * we need to use m_copydata() to get data from <n->m_next, 0>.

         */

        if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen &&

            !sharedcluster) {

                m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);

                n->m_len += tlen;

                m_adj(n->m_next, tlen);

                goto ok;

        }

        if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen &&

            !sharedcluster) {

                n->m_next->m_data -= hlen;

                n->m_next->m_len += hlen;

                bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);

                n->m_len -= hlen;

                n = n->m_next;

                off = 0;

                goto ok;

        }

        /*

         * now, we need to do the hard way.  don't m_copy as there's no room

         * on both end.

         */

#ifdef PULLDOWN_STAT

        mbstat.m_pulldown_alloc++;

#endif

        MGET(o, M_DONTWAIT, m->m_type);

        if (o && len > MLEN) {

                MCLGET(o, M_DONTWAIT);

                if ((o->m_flags & M_EXT) == 0) {

                        m_free(o);

                        o = NULL;

                }

        }

        if (!o) {

                m_freem(m);

                return NULL;    /* ENOBUFS */

        }

        /* get hlen from <n, off> into <o, 0> */

        o->m_len = hlen;

        bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen);

        n->m_len -= hlen;

        /* get tlen from <n->m_next, 0> into <o, hlen> */

        m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len);

        o->m_len += tlen;

        m_adj(n->m_next, tlen);

        o->m_next = n->m_next;

        n->m_next = o;

        n = o;

        off = 0;

ok:

#ifdef PULLDOWN_DEBUG

    {

        struct mbuf *t;

        printf("after:");

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

                printf("%c%d", t == n ? '*' : ' ', t->m_len);

        printf(" (off=%d)\n", off);

    }

#endif

        if (offp)

                *offp = off;

        return n;

}

#ifndef __NetBSD__

static struct mbuf *

m_dup1(m, off, len, wait)

        struct mbuf *m;

        int off;

        int len;

        int wait;

{

        struct mbuf *n;

        int l;

        int copyhdr;

        if (len > MCLBYTES)

                return NULL;

        if (off == 0 && (m->m_flags & M_PKTHDR) != 0) {

                copyhdr = 1;

                MGETHDR(n, wait, m->m_type);

                l = MHLEN;

        } else {

                copyhdr = 0;

                MGET(n, wait, m->m_type);

                l = MLEN;

        }

        if (n && len > l) {

                MCLGET(n, wait);

                if ((n->m_flags & M_EXT) == 0) {

                        m_free(n);

                        n = NULL;

                }

        }

        if (!n)

                return NULL;

        if (copyhdr) {

#ifdef __OpenBSD__

                M_MOVE_PKTHDR(n, m);

#else

                M_COPY_PKTHDR(n, m);

#endif

        }

        m_copydata(m, off, len, mtod(n, caddr_t));

        n->m_len = len;

        return n;

}

#endif

/*

 * pkthdr.aux chain manipulation.

 * we don't allow clusters at this moment.

 */

struct mbuf *

m_aux_add2(m, af, type, p)

        struct mbuf *m;

        int af, type;

        void *p;

{

        struct mbuf *n;

        struct mauxtag *t;

        if ((m->m_flags & M_PKTHDR) == 0)

                return NULL;

        n = m_aux_find(m, af, type);

        if (n)

                return n;

        MGET(n, M_DONTWAIT, m->m_type);

        if (n == NULL)

                return NULL;

        t = mtod(n, struct mauxtag *);

        bzero(t, sizeof(*t));

        t->af = af;

        t->type = type;

        t->p = p;

        n->m_data += sizeof(struct mauxtag);

        n->m_len = 0;

        n->m_next = m->m_pkthdr.aux;

        m->m_pkthdr.aux = n;

        return n;

}

struct mbuf *

m_aux_find2(m, af, type, p)

        struct mbuf *m;

        int af, type;

        void *p;

{

        struct mbuf *n;

        struct mauxtag *t;

        if ((m->m_flags & M_PKTHDR) == 0)

                return NULL;

        for (n = m->m_pkthdr.aux; n; n = n->m_next) {

                t = (struct mauxtag *)n->m_dat;

                if (n->m_data != ((caddr_t)t) + sizeof(struct mauxtag)) {

                        printf("m_aux_find: invalid m_data for mbuf=%p (%p %p)\n", n, t, n->m_data);

                        continue;

                }

                if (t->af == af && t->type == type && t->p == p)

                        return n;

        }

        return NULL;

}

struct mbuf *

m_aux_find(m, af, type)

        struct mbuf *m;

        int af, type;

{

        return m_aux_find2(m, af, type, NULL);

}

struct mbuf *

m_aux_add(m, af, type)

        struct mbuf *m;

        int af, type;

{

        return m_aux_add2(m, af, type, NULL);

}

void

m_aux_delete(m, victim)

        struct mbuf *m;

        struct mbuf *victim;

{

        struct mbuf *n, *prev, *next;

        struct mauxtag *t;

        if ((m->m_flags & M_PKTHDR) == 0)

                return;

        prev = NULL;

        n = m->m_pkthdr.aux;

        while (n) {

                t = (struct mauxtag *)n->m_dat;

                next = n->m_next;

                if (n->m_data != ((caddr_t)t) + sizeof(struct mauxtag)) {

                        printf("m_aux_delete: invalid m_data for mbuf=%p (%p %p)\n", n, t, n->m_data);

                        prev = n;

                        n = next;

                        continue;

                }

                if (n == victim) {

                        if (prev)

                                prev->m_next = n->m_next;

                        else

                                m->m_pkthdr.aux = n->m_next;

                        n->m_next = NULL;

                        m_free(n);

                } else

                        prev = n;

                n = next;

        }

}

#ifdef __OpenBSD__

/* Get a packet tag structure along with specified data following. */

struct m_tag *

m_tag_get(type, len, wait)

        int type;

        int len;

        int wait;

{

        struct m_tag *t;

        if (len < 0)

                return (NULL);

        MALLOC(t, struct m_tag *, len + sizeof(struct m_tag), M_PACKET_TAGS,

            wait);

        if (t == NULL)

                return (NULL);

        t->m_tag_id = type;

        t->m_tag_len = len;

        return (t);

}

/* Free a packet tag. */

void

m_tag_free(t)

        struct m_tag *t;

{

        FREE(t, M_PACKET_TAGS);

}

/* Prepend a packet tag. */

void

m_tag_prepend(m, t)

        struct mbuf *m;

        struct m_tag *t;

{

        SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);

}

/* Unlink a packet tag. */

void

m_tag_unlink(m, t)

        struct mbuf *m;

        struct m_tag *t;

{

        SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);

}

/* Unlink and free a packet tag. */

void

m_tag_delete(m, t)

        struct mbuf *m;

        struct m_tag *t;

{

        m_tag_unlink(m, t);

        m_tag_free(t);

}

/* Unlink and free a packet tag chain, starting from given tag. */

void

m_tag_delete_chain(m, t)

        struct mbuf *m;

        struct m_tag *t;

{

        struct m_tag *p, *q;

        if (t != NULL)

                p = t;

        else

                p = SLIST_FIRST(&m->m_pkthdr.tags);

        if (p == NULL)

                return;

        while ((q = SLIST_NEXT(p, m_tag_link)) != NULL)

                m_tag_delete(m, q);

        m_tag_delete(m, p);

}

/* Find a tag, starting from a given position. */

struct m_tag *

m_tag_find(m, type, t)

        struct mbuf *m;

        int type;

        struct m_tag *t;

{

        struct m_tag *p;

        if (t == NULL)

                p = SLIST_FIRST(&m->m_pkthdr.tags);

        else

                p = SLIST_NEXT(t, m_tag_link);

        while (p != NULL) {

                if (p->m_tag_id == type)

                        return (p);

                p = SLIST_NEXT(p, m_tag_link);

        }

        return (NULL);

}

/* Copy a single tag. */

struct m_tag *

m_tag_copy(t)

        struct m_tag *t;

{

        struct m_tag *p;

        p = m_tag_get(t->m_tag_id, t->m_tag_len, M_NOWAIT);

        if (p == NULL)

                return (NULL);

        bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */

        return (p);

}

/*

 * Copy two tag chains. The destination mbuf (to) loses any attached

 * tags even if the operation fails. This should not be a problem, as

 * m_tag_copy_chain() is typically called with a newly-allocated

 * destination mbuf.

 */

int

m_tag_copy_chain(to, from)

        struct mbuf *to;

        struct mbuf *from;

{

        struct m_tag *p, *t, *tprev = NULL;

        m_tag_delete_chain(to, NULL);

        SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) {

                t = m_tag_copy(p);

                if (t == NULL) {

                        m_tag_delete_chain(to, NULL);

                        return (0);

                }

                if (tprev == NULL)

                        SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link);

                else {

                        SLIST_INSERT_AFTER(tprev, t, m_tag_link);

                        tprev = t;

                }

        }

        return (1);

}

/* Initialize tags on an mbuf. */

void

m_tag_init(m)

        struct mbuf *m;

{

        SLIST_INIT(&m->m_pkthdr.tags);

}

/* Get first tag in chain. */

struct m_tag *

m_tag_first(m)

        struct mbuf *m;

{

        return (SLIST_FIRST(&m->m_pkthdr.tags));

}

/* Get next tag in chain. */

struct m_tag *

m_tag_next(m, t)

        struct mbuf *m;

        struct m_tag *t;

{