uipc_mbuf.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

/*
 * 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	8.2 (Berkeley) 1/4/94
 * $Id: uipc_mbuf.c,v 1.7 2003/02/06 17:14:29 joel Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#define MBTYPES
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/domain.h>
#include <sys/protosw.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>

#if !defined(__rtems__)
static void mbinit __P((void *))  __attribute__ ((unused));
SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL)
#endif

struct mbuf *mbutl;
char	*mclrefcnt;
struct mbstat mbstat;
struct mbuf *mmbfree;
union mcluster *mclfree;
int	max_linkhdr;
int	max_protohdr;
int	max_hdr;
int	max_datalen;

/* "number of clusters of pages" */
#define NCL_INIT	1

#define NMB_INIT	16

/*
 * When MGET failes, ask protocols to free space when short of memory,
 * then re-attempt to allocate an mbuf.
 */
struct mbuf *
m_retry(i, t)
	int i, t;
{
	register struct mbuf *m;

	m_reclaim();
#define m_retry(i, t)	(struct mbuf *)0
	MGET(m, i, t);
#undef m_retry
	if (m != NULL)
		mbstat.m_wait++;
	else
		mbstat.m_drops++;
	return (m);
}

/*
 * As above; retry an MGETHDR.
 */
struct mbuf *
m_retryhdr(i, t)
	int i, t;
{
	register struct mbuf *m;

	m_reclaim();
#define m_retryhdr(i, t) (struct mbuf *)0
	MGETHDR(m, i, t);
#undef m_retryhdr
	if (m != NULL)
		mbstat.m_wait++;
	else
		mbstat.m_drops++;
	return (m);
}

void
m_reclaim(void)
{
	register struct domain *dp;
	register struct protosw *pr;
	int s = splimp();

	for (dp = domains; dp; dp = dp->dom_next)
		for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
			if (pr->pr_drain)
				(*pr->pr_drain)();
	splx(s);
	mbstat.m_drain++;
}

/*
 * Space allocation routines.
 * These are also available as macros
 * for critical paths.
 */
struct mbuf *
m_get(nowait, type)
	int nowait, type;
{
	register struct mbuf *m;

	MGET(m, nowait, type);
	return (m);
}

struct mbuf *
m_gethdr(nowait, type)
	int nowait, type;
{
	register struct mbuf *m;

	MGETHDR(m, nowait, type);
	return (m);
}

struct mbuf *
m_getclr(nowait, type)
	int nowait, type;
{
	register struct mbuf *m;

	MGET(m, nowait, type);
	if (m == 0)
		return (0);
	bzero(mtod(m, caddr_t), MLEN);
	return (m);
}

struct mbuf *
m_free(m)
	struct mbuf *m;
{
	register struct mbuf *n;

	MFREE(m, n);
	return (n);
}

void
m_freem(m)
	register struct mbuf *m;
{
	register struct mbuf *n;

	if (m == NULL)
		return;
	do {
		MFREE(m, n);
		m = n;
	} while (m);
}

/*
 * Mbuffer utility routines.
 */

/*
 * Lesser-used path for M_PREPEND:
 * allocate new mbuf to prepend to chain,
 * copy junk along.
 */
struct mbuf *
m_prepend(m, len, how)
	register struct mbuf *m;
	int len, how;
{
	struct mbuf *mn;

	MGET(mn, how, m->m_type);
	if (mn == (struct mbuf *)NULL) {
		m_freem(m);
		return ((struct mbuf *)NULL);
	}
	if (m->m_flags & M_PKTHDR) {
		M_COPY_PKTHDR(mn, m);
		m->m_flags &= ~M_PKTHDR;
	}
	mn->m_next = m;
	m = mn;
	if (len < MHLEN)
		MH_ALIGN(m, len);
	m->m_len = len;
	return (m);
}

/*
 * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
 * continuing for "len" bytes.  If len is M_COPYALL, copy to end of mbuf.
 * The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller.
 */
static int MCFail;

struct mbuf *
m_copym(m, off0, len, wait)
	register struct mbuf *m;
	int off0, wait;
	register int len;
{
	register struct mbuf *n, **np;
	register int off = off0;
	struct mbuf *top;
	int copyhdr = 0;

	if (off < 0 || len < 0)
		panic("m_copym");
	if (off == 0 && m->m_flags & M_PKTHDR)
		copyhdr = 1;
	while (off > 0) {
		if (m == 0)
			panic("m_copym");
		if (off < m->m_len)
			break;
		off -= m->m_len;
		m = m->m_next;
	}
	np = &top;
	top = 0;
	while (len > 0) {
		if (m == 0) {
			if (len != M_COPYALL)
				panic("m_copym");
			break;
		}
		MGET(n, wait, m->m_type);
		*np = n;
		if (n == 0)
			goto nospace;
		if (copyhdr) {
			M_COPY_PKTHDR(n, m);
			if (len == M_COPYALL)
				n->m_pkthdr.len -= off0;
			else
				n->m_pkthdr.len = len;
			copyhdr = 0;
		}
		n->m_len = min(len, m->m_len - off);
		if (m->m_flags & M_EXT) {
			n->m_data = m->m_data + off;
			if(!m->m_ext.ext_ref)
				mclrefcnt[mtocl(m->m_ext.ext_buf)]++;
			else
				(*(m->m_ext.ext_ref))(m->m_ext.ext_buf,
							m->m_ext.ext_size);
			n->m_ext = m->m_ext;
			n->m_flags |= M_EXT;
		} else
			bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
			    (unsigned)n->m_len);
		if (len != M_COPYALL)
			len -= n->m_len;
		off = 0;
		m = m->m_next;
		np = &n->m_next;
	}
	if (top == 0)
		MCFail++;
	return (top);
nospace:
	m_freem(top);
	MCFail++;
	return (0);
}

/*
 * Copy an entire packet, including header (which must be present).
 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
 */
struct mbuf *
m_copypacket(m, how)
	struct mbuf *m;
	int how;
{
	struct mbuf *top, *n, *o;

	MGET(n, how, m->m_type);
	top = n;
	if (!n)
		goto nospace;

	M_COPY_PKTHDR(n, m);
	n->m_len = m->m_len;
	if (m->m_flags & M_EXT) {
		n->m_data = m->m_data;
		mclrefcnt[mtocl(m->m_ext.ext_buf)]++;
		n->m_ext = m->m_ext;
		n->m_flags |= M_EXT;
	} else {
		bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
	}

	m = m->m_next;
	while (m) {
		MGET(o, how, m->m_type);
		if (!o)
			goto nospace;

		n->m_next = o;
		n = n->m_next;

		n->m_len = m->m_len;
		if (m->m_flags & M_EXT) {
			n->m_data = m->m_data;
			mclrefcnt[mtocl(m->m_ext.ext_buf)]++;
			n->m_ext = m->m_ext;
			n->m_flags |= M_EXT;
		} else {
			bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
		}

		m = m->m_next;
	}
	return top;
nospace:
	m_freem(top);
	MCFail++;
	return 0;
}

/*
 * Copy data from an mbuf chain starting "off" bytes from the beginning,
 * continuing for "len" bytes, into the indicated buffer. Return -1 if requested
 * size is bigger than available
 */
int
m_copydata(m, off, len, cp)
	register struct mbuf *m;
	register int off;
	register int len;
	caddr_t cp;
{
	register unsigned count;
/*	struct mbuf *m0 = m; */

	if (off < 0 || len < 0)
		panic("m_copydata");
	while (off > 0) {
		if (m == 0) {
			/*printf("m_copydata: offset > mbuf length (");
			while(m0) {
			    printf("[%d] ",m0->m_len);
			    m0 = m0->m_next;
			}
			printf(")\n");*/
			return -1;
		}
		if (off < m->m_len)
			break;
		off -= m->m_len;
		m = m->m_next;
	}
	while (len > 0) {