[apple/xnu.git] / bsd / kern / uipc_mbuf2.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code 
 * as defined in and that are subject to the Apple Public Source License 
 * Version 2.0 (the 'License'). You may not use this file except in 
 * compliance with the License.  The rights granted to you under the 
 * License may not be used to create, or enable the creation or 
 * redistribution of, unlawful or unlicensed copies of an Apple operating 
 * system, or to circumvent, violate, or enable the circumvention or 
 * violation of, any terms of an Apple operating system software license 
 * agreement.
 *
 * Please obtain a copy of the License at 
 * http://www.opensource.apple.com/apsl/ and read it before using this 
 * file.
 *
 * The Original Code and all software distributed under the License are 
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
 * Please see the License for the specific language governing rights and 
 * limitations under the License.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
 */
/*      $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
 */


/*#define PULLDOWN_DEBUG*/

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc_internal.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#if defined(PULLDOWN_STAT) && defined(INET6)
#include <netinet/in.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#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;
#if defined(PULLDOWN_STAT) && defined(INET6)
        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 */
        }

#if defined(PULLDOWN_STAT) && defined(INET6)
        ip6stat.ip6s_pulldown++;
#endif

#if defined(PULLDOWN_STAT) && defined(INET6)
        /* statistics for m_pullup */
        ip6stat.ip6s_pullup++;
        if (off + len > MHLEN)
                ip6stat.ip6s_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)
                        ip6stat.ip6s_pullup--; /* call will not be made! */
                else if ((m->m_flags & M_EXT) != 0) {
                        ip6stat.ip6s_pullup_alloc++;
                        ip6stat.ip6s_pullup_copy++;
                } else {
                        if (mlen >= off + len)
                                ip6stat.ip6s_pullup_copy++;
                        else {
                                ip6stat.ip6s_pullup_alloc++;
                                ip6stat.ip6s_pullup_copy++;
                        }
                }

                prevlen = off + len;
                prevmlen = MHLEN;
        }

        /* statistics for m_pullup2 */
        ip6stat.ip6s_pullup2++;
        if (off + len > MCLBYTES)
                ip6stat.ip6s_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)
                        ip6stat.ip6s_pullup2--; /* call will not be made! */
                else if ((m->m_flags & M_EXT) != 0) {
                        ip6stat.ip6s_pullup2_alloc++;
                        ip6stat.ip6s_pullup2_copy++;
                        prevmlen = (off + len > MHLEN) ? MCLBYTES : MHLEN;
                } else {
                        if (mlen >= off + len)
                                ip6stat.ip6s_pullup2_copy++;
                        else {
                                ip6stat.ip6s_pullup2_alloc++;
                                ip6stat.ip6s_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 */
        }

        /*
         * 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)
                goto ok;

#if defined(PULLDOWN_STAT) && defined(INET6)
        ip6stat.ip6s_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) {
                o = m_copym(n, off, n->m_len - off, M_DONTWAIT);
                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 ((n->m_flags & M_EXT) == 0)
                sharedcluster = 0;
        else {
                if (n->m_ext.ext_free)
                        sharedcluster = 1;
                else if (m_mclhasreference(n))
                        sharedcluster = 1;
                else
                        sharedcluster = 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.
         */
#if defined(PULLDOWN_STAT) && defined(INET6)
        ip6stat.ip6s_pulldown_alloc++;
#endif
        MGET(o, M_DONTWAIT, m->m_type);
        if (o == NULL) {
                m_freem(m);
                return NULL;    /* ENOBUFS */
        }
        if (len > MHLEN) {      /* use MHLEN just for safety */
                MCLGET(o, M_DONTWAIT);
                if ((o->m_flags & M_EXT) == 0) {
                        m_freem(m);
                        m_free(o);
                        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;
}

/*
 * pkthdr.aux chain manipulation.
 * we don't allow clusters at this moment. 
 */
struct mbuf *
m_aux_add(m, af, type)
        struct mbuf *m;
        int af, type;
{
        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 *);
        t->af = af;
        t->type = type;
        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_find(m, af, type)
        struct mbuf *m;
        int af, type;
{
        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 (t->af == af && t->type == type)
                        return n;
        }
        return 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 == 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;
        }
}

/* Get a packet tag structure along with specified data following. */
struct m_tag *
m_tag_alloc(u_int32_t id, u_int16_t type, int len, int wait)
{
        struct m_tag *t;

        if (len < 0)
                return NULL;
#ifndef __APPLE__
        t = malloc(len + sizeof(struct m_tag), M_PACKET_TAGS, wait);
#else
        /*MALLOC(t, struct m_tag *, len + sizeof(struct m_tag), M_TEMP, M_WAITOK);*/
        if (len + sizeof(struct m_tag) <= MLEN) {
                struct mbuf *m = m_get(wait, MT_TAG);
                if (m == NULL)
                        return NULL;
                t = (struct m_tag *) m->m_dat;
        } else if (len + sizeof(struct m_tag) <= MCLBYTES) {
                MCLALLOC((caddr_t)t, wait);
        } else
                t = NULL;
#endif
        if (t == NULL)
                return NULL;
        t->m_tag_type = type;
        t->m_tag_len = len;
        t->m_tag_id = id;
        return t;
}


/* Free a packet tag. */
void
m_tag_free(struct m_tag *t)
{
#ifndef __APPLE__
        free(t, M_PACKET_TAGS);
#else
        /* FREE(t, M_TEMP); */
        if (t == NULL)
                return;
        if (t->m_tag_len <= MLEN) {
                struct mbuf * m = m_dtom(t);
                m_free(m);
        } else {
                MCLFREE((caddr_t)t);
        }
#endif
}

/* Prepend a packet tag. */
void
m_tag_prepend(struct mbuf *m, struct m_tag *t)
{
        KASSERT(m && t, ("m_tag_prepend: null argument, m %p t %p", m, t));
        SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
}

/* Unlink a packet tag. */
void
m_tag_unlink(struct mbuf *m, struct m_tag *t)
{
        KASSERT(m && t, ("m_tag_unlink: null argument, m %p t %p", m, t));
        SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
}

/* Unlink and free a packet tag. */
void
m_tag_delete(struct mbuf *m, struct m_tag *t)
{
        KASSERT(m && t, ("m_tag_delete: null argument, m %p t %p", m, 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(struct mbuf *m, struct m_tag *t)
{
        struct m_tag *p, *q;

        KASSERT(m, ("m_tag_delete_chain: null mbuf"));
        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_locate(struct mbuf *m, u_int32_t id, u_int16_t type, struct m_tag *t)
{
        struct m_tag *p;

        KASSERT(m, ("m_tag_find: null mbuf"));
        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 == id && p->m_tag_type == type)
                        return p;
                p = SLIST_NEXT(p, m_tag_link);
        }
        return NULL;
}

/* Copy a single tag. */
struct m_tag *
m_tag_copy(struct m_tag *t, int how)
{
        struct m_tag *p;

        KASSERT(t, ("m_tag_copy: null tag"));
        p = m_tag_alloc(t->m_tag_id, t->m_tag_type, t->m_tag_len, how);
        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(struct mbuf *to, struct mbuf *from, int how)
{
        struct m_tag *p, *t, *tprev = NULL;

        KASSERT(to && from,
                ("m_tag_copy: null argument, to %p from %p", to, from));
        m_tag_delete_chain(to, NULL);
        SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) {
                t = m_tag_copy(p, how);
                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(struct mbuf *m)
{
        SLIST_INIT(&m->m_pkthdr.tags);
}

/* Get first tag in chain. */
struct m_tag *
m_tag_first(struct mbuf *m)
{
        return SLIST_FIRST(&m->m_pkthdr.tags);
}

/* Get next tag in chain. */
struct m_tag *
m_tag_next(__unused struct mbuf *m, struct m_tag *t)
{
        return SLIST_NEXT(t, m_tag_link);
}