Move files to match FreeBSD layout

1 files changed, 2123 insertions, 0 deletions

diff --git a/freebsd/sys/kern/uipc_mbuf.c b/freebsd/sys/kern/uipc_mbuf.c
new file mode 100644
index 00000000..8e57835c
--- /dev/null
+++ b/freebsd/sys/kern/uipc_mbuf.c
@@ -0,0 +1,2123 @@
+#include <freebsd/machine/rtems-bsd-config.h>
+
+/*-
+ * 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.
+ * 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
+ */
+
+#include <freebsd/sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <freebsd/local/opt_param.h>
+#include <freebsd/local/opt_mbuf_stress_test.h>
+#include <freebsd/local/opt_mbuf_profiling.h>
+
+#include <freebsd/sys/param.h>
+#include <freebsd/sys/systm.h>
+#include <freebsd/sys/kernel.h>
+#include <freebsd/sys/limits.h>
+#include <freebsd/sys/lock.h>
+#include <freebsd/sys/malloc.h>
+#include <freebsd/sys/mbuf.h>
+#include <freebsd/sys/sysctl.h>
+#include <freebsd/sys/domain.h>
+#include <freebsd/sys/protosw.h>
+#include <freebsd/sys/uio.h>
+
+int	max_linkhdr;
+int	max_protohdr;
+int	max_hdr;
+int	max_datalen;
+#ifdef MBUF_STRESS_TEST
+int	m_defragpackets;
+int	m_defragbytes;
+int	m_defraguseless;
+int	m_defragfailure;
+int	m_defragrandomfailures;
+#endif
+
+/*
+ * sysctl(8) exported objects
+ */
+SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RD,
+	   &max_linkhdr, 0, "Size of largest link layer header");
+SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RD,
+	   &max_protohdr, 0, "Size of largest protocol layer header");
+SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RD,
+	   &max_hdr, 0, "Size of largest link plus protocol header");
+SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RD,
+	   &max_datalen, 0, "Minimum space left in mbuf after max_hdr");
+#ifdef MBUF_STRESS_TEST
+SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD,
+	   &m_defragpackets, 0, "");
+SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD,
+	   &m_defragbytes, 0, "");
+SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD,
+	   &m_defraguseless, 0, "");
+SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD,
+	   &m_defragfailure, 0, "");
+SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW,
+	   &m_defragrandomfailures, 0, "");
+#endif
+
+/*
+ * Allocate a given length worth of mbufs and/or clusters (whatever fits
+ * best) and return a pointer to the top of the allocated chain.  If an
+ * existing mbuf chain is provided, then we will append the new chain
+ * to the existing one but still return the top of the newly allocated
+ * chain.
+ */
+struct mbuf *
+m_getm2(struct mbuf *m, int len, int how, short type, int flags)
+{
+	struct mbuf *mb, *nm = NULL, *mtail = NULL;
+
+	KASSERT(len >= 0, ("%s: len is < 0", __func__));
+
+	/* Validate flags. */
+	flags &= (M_PKTHDR | M_EOR);
+
+	/* Packet header mbuf must be first in chain. */
+	if ((flags & M_PKTHDR) && m != NULL)
+		flags &= ~M_PKTHDR;
+
+	/* Loop and append maximum sized mbufs to the chain tail. */
+	while (len > 0) {
+		if (len > MCLBYTES)
+			mb = m_getjcl(how, type, (flags & M_PKTHDR),
+			    MJUMPAGESIZE);
+		else if (len >= MINCLSIZE)
+			mb = m_getcl(how, type, (flags & M_PKTHDR));
+		else if (flags & M_PKTHDR)
+			mb = m_gethdr(how, type);
+		else
+			mb = m_get(how, type);
+
+		/* Fail the whole operation if one mbuf can't be allocated. */
+		if (mb == NULL) {
+			if (nm != NULL)
+				m_freem(nm);
+			return (NULL);
+		}
+
+		/* Book keeping. */
+		len -= (mb->m_flags & M_EXT) ? mb->m_ext.ext_size :
+			((mb->m_flags & M_PKTHDR) ? MHLEN : MLEN);
+		if (mtail != NULL)
+			mtail->m_next = mb;
+		else
+			nm = mb;
+		mtail = mb;
+		flags &= ~M_PKTHDR;	/* Only valid on the first mbuf. */
+	}
+	if (flags & M_EOR)
+		mtail->m_flags |= M_EOR;  /* Only valid on the last mbuf. */
+
+	/* If mbuf was supplied, append new chain to the end of it. */
+	if (m != NULL) {
+		for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next)
+			;
+		mtail->m_next = nm;
+		mtail->m_flags &= ~M_EOR;
+	} else
+		m = nm;
+
+	return (m);
+}
+
+/*
+ * Free an entire chain of mbufs and associated external buffers, if
+ * applicable.
+ */
+void
+m_freem(struct mbuf *mb)
+{
+
+	while (mb != NULL)
+		mb = m_free(mb);
+}
+
+/*-
+ * Configure a provided mbuf to refer to the provided external storage
+ * buffer and setup a reference count for said buffer.  If the setting
+ * up of the reference count fails, the M_EXT bit will not be set.  If
+ * successfull, the M_EXT bit is set in the mbuf's flags.
+ *
+ * Arguments:
+ *    mb     The existing mbuf to which to attach the provided buffer.
+ *    buf    The address of the provided external storage buffer.
+ *    size   The size of the provided buffer.
+ *    freef  A pointer to a routine that is responsible for freeing the
+ *           provided external storage buffer.
+ *    args   A pointer to an argument structure (of any type) to be passed
+ *           to the provided freef routine (may be NULL).
+ *    flags  Any other flags to be passed to the provided mbuf.
+ *    type   The type that the external storage buffer should be
+ *           labeled with.
+ *
+ * Returns:
+ *    Nothing.
+ */
+void
+m_extadd(struct mbuf *mb, caddr_t buf, u_int size,
+    void (*freef)(void *, void *), void *arg1, void *arg2, int flags, int type)
+{
+	KASSERT(type != EXT_CLUSTER, ("%s: EXT_CLUSTER not allowed", __func__));
+
+	if (type != EXT_EXTREF)
+		mb->m_ext.ref_cnt = (u_int *)uma_zalloc(zone_ext_refcnt, M_NOWAIT);
+	if (mb->m_ext.ref_cnt != NULL) {
+		*(mb->m_ext.ref_cnt) = 1;
+		mb->m_flags |= (M_EXT | flags);
+		mb->m_ext.ext_buf = buf;
+		mb->m_data = mb->m_ext.ext_buf;
+		mb->m_ext.ext_size = size;
+		mb->m_ext.ext_free = freef;
+		mb->m_ext.ext_arg1 = arg1;
+		mb->m_ext.ext_arg2 = arg2;
+		mb->m_ext.ext_type = type;
+        }
+}
+
+/*
+ * Non-directly-exported function to clean up after mbufs with M_EXT
+ * storage attached to them if the reference count hits 1.
+ */
+void
+mb_free_ext(struct mbuf *m)
+{
+	int skipmbuf;
+
+	KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
+	KASSERT(m->m_ext.ref_cnt != NULL, ("%s: ref_cnt not set", __func__));
+
+
+	/*
+	 * check if the header is embedded in the cluster
+	 */
+	skipmbuf = (m->m_flags & M_NOFREE);
+
+	/* Free attached storage if this mbuf is the only reference to it. */
+	if (*(m->m_ext.ref_cnt) == 1 ||
+	    atomic_fetchadd_int(m->m_ext.ref_cnt, -1) == 1) {
+		switch (m->m_ext.ext_type) {
+		case EXT_PACKET:	/* The packet zone is special. */
+			if (*(m->m_ext.ref_cnt) == 0)
+				*(m->m_ext.ref_cnt) = 1;
+			uma_zfree(zone_pack, m);
+			return;		/* Job done. */
+		case EXT_CLUSTER:
+			uma_zfree(zone_clust, m->m_ext.ext_buf);
+			break;
+		case EXT_JUMBOP:
+			uma_zfree(zone_jumbop, m->m_ext.ext_buf);
+			break;
+		case EXT_JUMBO9:
+			uma_zfree(zone_jumbo9, m->m_ext.ext_buf);
+			break;
+		case EXT_JUMBO16:
+			uma_zfree(zone_jumbo16, m->m_ext.ext_buf);
+			break;
+		case EXT_SFBUF:
+		case EXT_NET_DRV:
+		case EXT_MOD_TYPE:
+		case EXT_DISPOSABLE:
+			*(m->m_ext.ref_cnt) = 0;
+			uma_zfree(zone_ext_refcnt, __DEVOLATILE(u_int *,
+				m->m_ext.ref_cnt));
+			/* FALLTHROUGH */
+		case EXT_EXTREF:
+			KASSERT(m->m_ext.ext_free != NULL,
+				("%s: ext_free not set", __func__));
+			(*(m->m_ext.ext_free))(m->m_ext.ext_arg1,
+			    m->m_ext.ext_arg2);
+			break;
+		default:
+			KASSERT(m->m_ext.ext_type == 0,
+				("%s: unknown ext_type", __func__));
+		}
+	}
+	if (skipmbuf)
+		return;
+
+	/*
+	 * Free this mbuf back to the mbuf zone with all m_ext
+	 * information purged.
+	 */
+	m->m_ext.ext_buf = NULL;
+	m->m_ext.ext_free = NULL;
+	m->m_ext.ext_arg1 = NULL;
+	m->m_ext.ext_arg2 = NULL;
+	m->m_ext.ref_cnt = NULL;
+	m->m_ext.ext_size = 0;
+	m->m_ext.ext_type = 0;
+	m->m_flags &= ~M_EXT;
+	uma_zfree(zone_mbuf, m);
+}
+
+/*
+ * Attach the the cluster from *m to *n, set up m_ext in *n
+ * and bump the refcount of the cluster.
+ */
+static void
+mb_dupcl(struct mbuf *n, struct mbuf *m)
+{
+	KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
+	KASSERT(m->m_ext.ref_cnt != NULL, ("%s: ref_cnt not set", __func__));
+	KASSERT((n->m_flags & M_EXT) == 0, ("%s: M_EXT set", __func__));
+
+	if (*(m->m_ext.ref_cnt) == 1)
+		*(m->m_ext.ref_cnt) += 1;
+	else
+		atomic_add_int(m->m_ext.ref_cnt, 1);
+	n->m_ext.ext_buf = m->m_ext.ext_buf;
+	n->m_ext.ext_free = m->m_ext.ext_free;
+	n->m_ext.ext_arg1 = m->m_ext.ext_arg1;
+	n->m_ext.ext_arg2 = m->m_ext.ext_arg2;
+	n->m_ext.ext_size = m->m_ext.ext_size;
+	n->m_ext.ref_cnt = m->m_ext.ref_cnt;
+	n->m_ext.ext_type = m->m_ext.ext_type;
+	n->m_flags |= M_EXT;
+	n->m_flags |= m->m_flags & M_RDONLY;
+}
+
+/*
+ * Clean up mbuf (chain) from any tags and packet headers.
+ * If "all" is set then the first mbuf in the chain will be
+ * cleaned too.
+ */
+void
+m_demote(struct mbuf *m0, int all)
+{
+	struct mbuf *m;
+
+	for (m = all ? m0 : m0->m_next; m != NULL; m = m->m_next) {
+		if (m->m_flags & M_PKTHDR) {
+			m_tag_delete_chain(m, NULL);
+			m->m_flags &= ~M_PKTHDR;
+			bzero(&m->m_pkthdr, sizeof(struct pkthdr));
+		}
+		if (m != m0 && m->m_nextpkt != NULL) {
+			KASSERT(m->m_nextpkt == NULL,
+			    ("%s: m_nextpkt not NULL", __func__));
+			m_freem(m->m_nextpkt);
+			m->m_nextpkt = NULL;
+		}
+		m->m_flags = m->m_flags & (M_EXT|M_RDONLY|M_FREELIST|M_NOFREE);
+	}
+}
+
+/*
+ * Sanity checks on mbuf (chain) for use in KASSERT() and general
+ * debugging.
+ * Returns 0 or panics when bad and 1 on all tests passed.
+ * Sanitize, 0 to run M_SANITY_ACTION, 1 to garble things so they
+ * blow up later.
+ */
+int
+m_sanity(struct mbuf *m0, int sanitize)
+{
+	struct mbuf *m;
+	caddr_t a, b;
+	int pktlen = 0;
+
+#ifdef INVARIANTS
+#define	M_SANITY_ACTION(s)	panic("mbuf %p: " s, m)
+#else
+#define	M_SANITY_ACTION(s)	printf("mbuf %p: " s, m)
+#endif
+
+	for (m = m0; m != NULL; m = m->m_next) {
+		/*
+		 * Basic pointer checks.  If any of these fails then some
+		 * unrelated kernel memory before or after us is trashed.
+		 * No way to recover from that.
+		 */
+		a = ((m->m_flags & M_EXT) ? m->m_ext.ext_buf :
+			((m->m_flags & M_PKTHDR) ? (caddr_t)(&m->m_pktdat) :
+			 (caddr_t)(&m->m_dat)) );
+		b = (caddr_t)(a + (m->m_flags & M_EXT ? m->m_ext.ext_size :
+			((m->m_flags & M_PKTHDR) ? MHLEN : MLEN)));
+		if ((caddr_t)m->m_data < a)
+			M_SANITY_ACTION("m_data outside mbuf data range left");
+		if ((caddr_t)m->m_data > b)
+			M_SANITY_ACTION("m_data outside mbuf data range right");
+		if ((caddr_t)m->m_data + m->m_len > b)
+			M_SANITY_ACTION("m_data + m_len exeeds mbuf space");
+		if ((m->m_flags & M_PKTHDR) && m->m_pkthdr.header) {
+			if ((caddr_t)m->m_pkthdr.header < a ||
+			    (caddr_t)m->m_pkthdr.header > b)
+				M_SANITY_ACTION("m_pkthdr.header outside mbuf data range");
+		}
+
+		/* m->m_nextpkt may only be set on first mbuf in chain. */
+		if (m != m0 && m->m_nextpkt != NULL) {
+			if (sanitize) {
+				m_freem(m->m_nextpkt);
+				m->m_nextpkt = (struct mbuf *)0xDEADC0DE;
+			} else
+				M_SANITY_ACTION("m->m_nextpkt on in-chain mbuf");
+		}
+
+		/* packet length (not mbuf length!) calculation */
+		if (m0->m_flags & M_PKTHDR)
+			pktlen += m->m_len;
+
+		/* m_tags may only be attached to first mbuf in chain. */
+		if (m != m0 && m->m_flags & M_PKTHDR &&
+		    !SLIST_EMPTY(&m->m_pkthdr.tags)) {
+			if (sanitize) {
+				m_tag_delete_chain(m, NULL);
+				/* put in 0xDEADC0DE perhaps? */
+			} else
+				M_SANITY_ACTION("m_tags on in-chain mbuf");
+		}
+
+		/* M_PKTHDR may only be set on first mbuf in chain */
+		if (m != m0 && m->m_flags & M_PKTHDR) {
+			if (sanitize) {
+				bzero(&m->m_pkthdr, sizeof(m->m_pkthdr));
+				m->m_flags &= ~M_PKTHDR;
+				/* put in 0xDEADCODE and leave hdr flag in */
+			} else
+				M_SANITY_ACTION("M_PKTHDR on in-chain mbuf");
+		}
+	}
+	m = m0;
+	if (pktlen && pktlen != m->m_pkthdr.len) {
+		if (sanitize)
+			m->m_pkthdr.len = 0;
+		else
+			M_SANITY_ACTION("m_pkthdr.len != mbuf chain length");
+	}
+	return 1;
+
+#undef	M_SANITY_ACTION
+}
+
+
+/*
+ * "Move" mbuf pkthdr from "from" to "to".
+ * "from" must have M_PKTHDR set, and "to" must be empty.
+ */
+void
+m_move_pkthdr(struct mbuf *to, struct mbuf *from)
+{
+
+#if 0
+	/* see below for why these are not enabled */
+	M_ASSERTPKTHDR(to);
+	/* Note: with MAC, this may not be a good assertion. */
+	KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags),
+	    ("m_move_pkthdr: to has tags"));
+#endif
+#ifdef MAC
+	/*
+	 * XXXMAC: It could be this should also occur for non-MAC?
+	 */
+	if (to->m_flags & M_PKTHDR)
+		m_tag_delete_chain(to, NULL);
+#endif
+	to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
+	if ((to->m_flags & M_EXT) == 0)
+		to->m_data = to->m_pktdat;
+	to->m_pkthdr = from->m_pkthdr;		/* especially tags */
+	SLIST_INIT(&from->m_pkthdr.tags);	/* purge tags from src */
+	from->m_flags &= ~M_PKTHDR;
+}
+
+/*
+ * Duplicate "from"'s mbuf pkthdr in "to".
+ * "from" must have M_PKTHDR set, and "to" must be empty.
+ * In particular, this does a deep copy of the packet tags.
+ */
+int
+m_dup_pkthdr(struct mbuf *to, struct mbuf *from, int how)
+{
+
+#if 0
+	/*
+	 * The mbuf allocator only initializes the pkthdr
+	 * when the mbuf is allocated with MGETHDR. Many users
+	 * (e.g. m_copy*, m_prepend) use MGET and then
+	 * smash the pkthdr as needed causing these
+	 * assertions to trip.  For now just disable them.
+	 */
+	M_ASSERTPKTHDR(to);
+	/* Note: with MAC, this may not be a good assertion. */
+	KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_dup_pkthdr: to has tags"));
+#endif
+	MBUF_CHECKSLEEP(how);
+#ifdef MAC
+	if (to->m_flags & M_PKTHDR)
+		m_tag_delete_chain(to, NULL);
+#endif
+	to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
+	if ((to->m_flags & M_EXT) == 0)
+		to->m_data = to->m_pktdat;
+	to->m_pkthdr = from->m_pkthdr;
+	SLIST_INIT(&to->m_pkthdr.tags);
+	return (m_tag_copy_chain(to, from, MBTOM(how)));
+}
+
+/*
+ * Lesser-used path for M_PREPEND:
+ * allocate new mbuf to prepend to chain,
+ * copy junk along.
+ */
+struct mbuf *
+m_prepend(struct mbuf *m, int len, int how)
+{
+	struct mbuf *mn;
+
+	if (m->m_flags & M_PKTHDR)
+		MGETHDR(mn, how, m->m_type);
+	else
+		MGET(mn, how, m->m_type);
+	if (mn == NULL) {
+		m_freem(m);
+		return (NULL);
+	}
+	if (m->m_flags & M_PKTHDR)
+		M_MOVE_PKTHDR(mn, m);
+	mn->m_next = m;
+	m = mn;
+	if(m->m_flags & M_PKTHDR) {
+		if (len < MHLEN)
+			MH_ALIGN(m, len);
+	} else {
+		if (len < MLEN)
+			M_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.
+ * Note that the copy is read-only, because clusters are not copied,
+ * only their reference counts are incremented.
+ */
+struct mbuf *
+m_copym(struct mbuf *m, int off0, int len, int wait)
+{
+	struct mbuf *n, **np;
+	int off = off0;
+	struct mbuf *top;
+	int copyhdr = 0;
+
+	KASSERT(off >= 0, ("m_copym, negative off %d", off));
+	KASSERT(len >= 0, ("m_copym, negative len %d", len));
+	MBUF_CHECKSLEEP(wait);
+	if (off == 0 && m->m_flags & M_PKTHDR)
+		copyhdr = 1;
+	while (off > 0) {
+		KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain"));
+		if (off < m->m_len)
+			break;
+		off -= m->m_len;
+		m = m->m_next;
+	}
+	np = &top;
+	top = 0;
+	while (len > 0) {
+		if (m == NULL) {
+			KASSERT(len == M_COPYALL,
+			    ("m_copym, length > size of mbuf chain"));
+			break;
+		}
+		if (copyhdr)
+			MGETHDR(n, wait, m->m_type);
+		else
+			MGET(n, wait, m->m_type);
+		*np = n;
+		if (n == NULL)
+			goto nospace;
+		if (copyhdr) {
+			if (!m_dup_pkthdr(n, m, wait))
+				goto nospace;
+			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;
+			mb_dupcl(n, m);
+		} else
+			bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
+			    (u_int)n->m_len);
+		if (len != M_COPYALL)
+			len -= n->m_len;
+		off = 0;
+		m = m->m_next;
+		np = &n->m_next;
+	}
+	if (top == NULL)
+		mbstat.m_mcfail++;	/* XXX: No consistency. */
+
+	return (top);
+nospace:
+	m_freem(top);
+	mbstat.m_mcfail++;	/* XXX: No consistency. */
+	return (NULL);
+}
+
+/*
+ * Returns mbuf chain with new head for the prepending case.
+ * Copies from mbuf (chain) n from off for len to mbuf (chain) m
+ * either prepending or appending the data.
+ * The resulting mbuf (chain) m is fully writeable.
+ * m is destination (is made writeable)
+ * n is source, off is offset in source, len is len from offset
+ * dir, 0 append, 1 prepend
+ * how, wait or nowait
+ */
+
+static int
+m_bcopyxxx(void *s, void *t, u_int len)
+{
+	bcopy(s, t, (size_t)len);
+	return 0;
+}
+
+struct mbuf *
+m_copymdata(struct mbuf *m, struct mbuf *n, int off, int len,
+    int prep, int how)
+{
+	struct mbuf *mm, *x, *z, *prev = NULL;
+	caddr_t p;
+	int i, nlen = 0;
+	caddr_t buf[MLEN];
+
+	KASSERT(m != NULL && n != NULL, ("m_copymdata, no target or source"));
+	KASSERT(off >= 0, ("m_copymdata, negative off %d", off));
+	KASSERT(len >= 0, ("m_copymdata, negative len %d", len));
+	KASSERT(prep == 0 || prep == 1, ("m_copymdata, unknown direction %d", prep));
+
+	mm = m;
+	if (!prep) {
+		while(mm->m_next) {
+			prev = mm;
+			mm = mm->m_next;
+		}
+	}
+	for (z = n; z != NULL; z = z->m_next)
+		nlen += z->m_len;
+	if (len == M_COPYALL)
+		len = nlen - off;
+	if (off + len > nlen || len < 1)
+		return NULL;
+
+	if (!M_WRITABLE(mm)) {
+		/* XXX: Use proper m_xxx function instead. */
+		x = m_getcl(how, MT_DATA, mm->m_flags);
+		if (x == NULL)
+			return NULL;
+		bcopy(mm->m_ext.ext_buf, x->m_ext.ext_buf, x->m_ext.ext_size);
+		p = x->m_ext.ext_buf + (mm->m_data - mm->m_ext.ext_buf);
+		x->m_data = p;
+		mm->m_next = NULL;
+		if (mm != m)
+			prev->m_next = x;
+		m_free(mm);
+		mm = x;
+	}
+
+	/*
+	 * Append/prepend the data.  Allocating mbufs as necessary.
+	 */
+	/* Shortcut if enough free space in first/last mbuf. */
+	if (!prep && M_TRAILINGSPACE(mm) >= len) {
+		m_apply(n, off, len, m_bcopyxxx, mtod(mm, caddr_t) +
+			 mm->m_len);
+		mm->m_len += len;
+		mm->m_pkthdr.len += len;
+		return m;
+	}
+	if (prep && M_LEADINGSPACE(mm) >= len) {
+		mm->m_data = mtod(mm, caddr_t) - len;
+		m_apply(n, off, len, m_bcopyxxx, mtod(mm, caddr_t));
+		mm->m_len += len;
+		mm->m_pkthdr.len += len;
+		return mm;
+	}
+
+	/* Expand first/last mbuf to cluster if possible. */
+	if (!prep && !(mm->m_flags & M_EXT) && len > M_TRAILINGSPACE(mm)) {
+		bcopy(mm->m_data, &buf, mm->m_len);
+		m_clget(mm, how);
+		if (!(mm->m_flags & M_EXT))
+			return NULL;
+		bcopy(&buf, mm->m_ext.ext_buf, mm->m_len);
+		mm->m_data = mm->m_ext.ext_buf;
+		mm->m_pkthdr.header = NULL;
+	}
+	if (prep && !(mm->m_flags & M_EXT) && len > M_LEADINGSPACE(mm)) {
+		bcopy(mm->m_data, &buf, mm->m_len);
+		m_clget(mm, how);
+		if (!(mm->m_flags & M_EXT))
+			return NULL;
+		bcopy(&buf, (caddr_t *)mm->m_ext.ext_buf +
+		       mm->m_ext.ext_size - mm->m_len, mm->m_len);
+		mm->m_data = (caddr_t)mm->m_ext.ext_buf +
+			      mm->m_ext.ext_size - mm->m_len;
+		mm->m_pkthdr.header = NULL;
+	}
+
+	/* Append/prepend as many mbuf (clusters) as necessary to fit len. */
+	if (!prep && len > M_TRAILINGSPACE(mm)) {
+		if (!m_getm(mm, len - M_TRAILINGSPACE(mm), how, MT_DATA))
+			return NULL;
+	}
+	if (prep && len > M_LEADINGSPACE(mm)) {
+		if (!(z = m_getm(NULL, len - M_LEADINGSPACE(mm), how, MT_DATA)))
+			return NULL;
+		i = 0;
+		for (x = z; x != NULL; x = x->m_next) {
+			i += x->m_flags & M_EXT ? x->m_ext.ext_size :
+			      (x->m_flags & M_PKTHDR ? MHLEN : MLEN);
+			if (!x->m_next)
+				break;
+		}
+		z->m_data += i - len;
+		m_move_pkthdr(mm, z);
+		x->m_next = mm;
+		mm = z;
+	}
+
+	/* Seek to start position in source mbuf. Optimization for long chains. */
+	while (off > 0) {
+		if (off < n->m_len)
+			break;
+		off -= n->m_len;
+		n = n->m_next;
+	}
+
+	/* Copy data into target mbuf. */
+	z = mm;
+	while (len > 0) {
+		KASSERT(z != NULL, ("m_copymdata, falling off target edge"));
+		i = M_TRAILINGSPACE(z);
+		m_apply(n, off, i, m_bcopyxxx, mtod(z, caddr_t) + z->m_len);
+		z->m_len += i;
+		/* fixup pkthdr.len if necessary */
+		if ((prep ? mm : m)->m_flags & M_PKTHDR)
+			(prep ? mm : m)->m_pkthdr.len += i;
+		off += i;
+		len -= i;
+		z = z->m_next;
+	}
+	return (prep ? mm : m);
+}
+
+/*
+ * Copy an entire packet, including header (which must be present).
+ * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
+ * Note that the copy is read-only, because clusters are not copied,
+ * only their reference counts are incremented.
+ * Preserve alignment of the first mbuf so if the creator has left
+ * some room at the beginning (e.g. for inserting protocol headers)
+ * the copies still have the room available.
+ */
+struct mbuf *
+m_copypacket(struct mbuf *m, int how)
+{
+	struct mbuf *top, *n, *o;
+
+	MBUF_CHECKSLEEP(how);
+	MGET(n, how, m->m_type);
+	top = n;
+	if (n == NULL)
+		goto nospace;
+
+	if (!m_dup_pkthdr(n, m, how))
+		goto nospace;
+	n->m_len = m->m_len;
+	if (m->m_flags & M_EXT) {
+		n->m_data = m->m_data;
+		mb_dupcl(n, m);
+	} else {
+		n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat );
+		bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
+	}
+
+	m = m->m_next;
+	while (m) {
+		MGET(o, how, m->m_type);
+		if (o == NULL)
+			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;
+			mb_dupcl(n, m);
+		} else {
+			bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
+		}
+
+		m = m->m_next;
+	}
+	return top;
+nospace:
+	m_freem(top);
+	mbstat.m_mcfail++;	/* XXX: No consistency. */
+	return (NULL);
+}
+
+/*
+ * Copy data from an mbuf chain starting "off" bytes from the beginning,
+ * continuing for "len" bytes, into the indicated buffer.
+ */
+void
+m_copydata(const struct mbuf *m, int off, int len, caddr_t cp)
+{
+	u_int count;
+
+	KASSERT(off >= 0, ("m_copydata, negative off %d", off));
+	KASSERT(len >= 0, ("m_copydata, negative len %d", len));
+	while (off > 0) {
+		KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain"));
+		if (off < m->m_len)
+			break;
+		off -= m->m_len;
+		m = m->m_next;
+	}
+	while (len > 0) {
+		KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain"));
+		count = min(m->m_len - off, len);
+		bcopy(mtod(m, caddr_t) + off, cp, count);
+		len -= count;
+		cp += count;
+		off = 0;
+		m = m->m_next;
+	}
+}
+
+/*
+ * Copy a packet header mbuf chain into a completely new chain, including
+ * copying any mbuf clusters.  Use this instead of m_copypacket() when
+ * you need a writable copy of an mbuf chain.
+ */
+struct mbuf *
+m_dup(struct mbuf *m, int how)
+{
+	struct mbuf **p, *top = NULL;
+	int remain, moff, nsize;
+
+	MBUF_CHECKSLEEP(how);
+	/* Sanity check */
+	if (m == NULL)
+		return (NULL);
+	M_ASSERTPKTHDR(m);
+
+	/* While there's more data, get a new mbuf, tack it on, and fill it */
+	remain = m->m_pkthdr.len;
+	moff = 0;
+	p = &top;
+	while (remain > 0 || top == NULL) {	/* allow m->m_pkthdr.len == 0 */
+		struct mbuf *n;
+
+		/* Get the next new mbuf */
+		if (remain >= MINCLSIZE) {
+			n = m_getcl(how, m->m_type, 0);
+			nsize = MCLBYTES;
+		} else {
+			n = m_get(how, m->m_type);
+			nsize = MLEN;
+		}
+		if (n == NULL)
+			goto nospace;
+
+		if (top == NULL) {		/* First one, must be PKTHDR */
+			if (!m_dup_pkthdr(n, m, how)) {
+				m_free(n);
+				goto nospace;
+			}
+			if ((n->m_flags & M_EXT) == 0)
+				nsize = MHLEN;
+		}
+		n->m_len = 0;
+
+		/* Link it into the new chain */
+		*p = n;
+		p = &n->m_next;
+
+		/* Copy data from original mbuf(s) into new mbuf */
+		while (n->m_len < nsize && m != NULL) {
+			int chunk = min(nsize - n->m_len, m->m_len - moff);
+
+			bcopy(m->m_data + moff, n->m_data + n->m_len, chunk);
+			moff += chunk;
+			n->m_len += chunk;
+			remain -= chunk;
+			if (moff == m->m_len) {
+				m = m->m_next;
+				moff = 0;
+			}
+		}
+
+		/* Check correct total mbuf length */
+		KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL),
+		    	("%s: bogus m_pkthdr.len", __func__));
+	}
+	return (top);
+
+nospace:
+	m_freem(top);
+	mbstat.m_mcfail++;	/* XXX: No consistency. */
+	return (NULL);
+}
+
+/*
+ * Concatenate mbuf chain n to m.
+ * Both chains must be of the same type (e.g. MT_DATA).
+ * Any m_pkthdr is not updated.
+ */
+void
+m_cat(struct mbuf *m, struct mbuf *n)
+{
+	while (m->m_next)
+		m = m->m_next;
+	while (n) {
+		if (m->m_flags & M_EXT ||
+		    m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) {
+			/* just join the two chains */
+			m->m_next = n;
+			return;
+		}
+		/* splat the data from one into the other */
+		bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
+		    (u_int)n->m_len);
+		m->m_len += n->m_len;
+		n = m_free(n);
+	}
+}
+
+void
+m_adj(struct mbuf *mp, int req_len)
+{
+	int len = req_len;
+	struct mbuf *m;
+	int count;
+
+	if ((m = mp) == NULL)
+		return;
+	if (len >= 0) {
+		/*
+		 * Trim from head.
+		 */
+		while (m != NULL && len > 0) {
+			if (m->m_len <= len) {
+				len -= m->m_len;
+				m->m_len = 0;
+				m = m->m_next;
+			} else {
+				m->m_len -= len;
+				m->m_data += len;
+				len = 0;
+			}
+		}
+		if (mp->m_flags & M_PKTHDR)
+			mp->m_pkthdr.len -= (req_len - len);
+	} else {
+		/*
+		 * Trim from tail.  Scan the mbuf chain,
+		 * calculating its length and finding the last mbuf.
+		 * If the adjustment only affects this mbuf, then just
+		 * adjust and return.  Otherwise, rescan and truncate
+		 * after the remaining size.
+		 */
+		len = -len;
+		count = 0;
+		for (;;) {
+			count += m->m_len;
+			if (m->m_next == (struct mbuf *)0)
+				break;
+			m = m->m_next;
+		}
+		if (m->m_len >= len) {
+			m->m_len -= len;
+			if (mp->m_flags & M_PKTHDR)
+				mp->m_pkthdr.len -= len;
+			return;
+		}
+		count -= len;
+		if (count < 0)
+			count = 0;
+		/*
+		 * Correct length for chain is "count".
+		 * Find the mbuf with last data, adjust its length,
+		 * and toss data from remaining mbufs on chain.
+		 */
+		m = mp;
+		if (m->m_flags & M_PKTHDR)
+			m->m_pkthdr.len = count;
+		for (; m; m = m->m_next) {
+			if (m->m_len >= count) {
+				m->m_len = count;
+				if (m->m_next != NULL) {
+					m_freem(m->m_next);
+					m->m_next = NULL;
+				}
+				break;
+			}
+			count -= m->m_len;
+		}
+	}
+}
+
+/*
+ * Rearange an mbuf chain so that len bytes are contiguous
+ * and in the data area of an mbuf (so that mtod and dtom
+ * will work for a structure of size len).  Returns the resulting
+ * mbuf chain on success, frees it and returns null on failure.
+ * If there is room, it will add up to max_protohdr-len extra bytes to the
+ * contiguous region in an attempt to avoid being called next time.
+ */
+struct mbuf *
+m_pullup(struct mbuf *n, int len)
+{
+	struct mbuf *m;
+	int count;
+	int space;
+
+	/*
+	 * If first mbuf has no cluster, and has room for len bytes
+	 * without shifting current data, pullup into it,
+	 * otherwise allocate a new mbuf to prepend to the chain.
+	 */
+	if ((n->m_flags & M_EXT) == 0 &&
+	    n->m_data + len < &n->m_dat[MLEN] && n->m_next) {
+		if (n->m_len >= len)
+			return (n);
+		m = n;
+		n = n->m_next;
+		len -= m->m_len;
+	} else {
+		if (len > MHLEN)
+			goto bad;
+		MGET(m, M_DONTWAIT, n->m_type);
+		if (m == NULL)
+			goto bad;
+		m->m_len = 0;
+		if (n->m_flags & M_PKTHDR)
+			M_MOVE_PKTHDR(m, n);
+	}
+	space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
+	do {
+		count = min(min(max(len, max_protohdr), space), n->m_len);
+		bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
+		  (u_int)count);
+		len -= count;
+		m->m_len += count;
+		n->m_len -= count;
+		space -= count;
+		if (n->m_len)
+			n->m_data += count;
+		else
+			n = m_free(n);
+	} while (len > 0 && n);
+	if (len > 0) {
+		(void) m_free(m);
+		goto bad;
+	}
+	m->m_next = n;
+	return (m);
+bad:
+	m_freem(n);
+	mbstat.m_mpfail++;	/* XXX: No consistency. */
+	return (NULL);
+}
+
+/*
+ * Like m_pullup(), except a new mbuf is always allocated, and we allow
+ * the amount of empty space before the data in the new mbuf to be specified
+ * (in the event that the caller expects to prepend later).
+ */
+int MSFail;
+
+struct mbuf *
+m_copyup(struct mbuf *n, int len, int dstoff)
+{
+	struct mbuf *m;
+	int count, space;
+
+	if (len > (MHLEN - dstoff))
+		goto bad;
+	MGET(m, M_DONTWAIT, n->m_type);
+	if (m == NULL)
+		goto bad;
+	m->m_len = 0;
+	if (n->m_flags & M_PKTHDR)
+		M_MOVE_PKTHDR(m, n);
+	m->m_data += dstoff;
+	space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
+	do {
+		count = min(min(max(len, max_protohdr), space), n->m_len);
+		memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t),
+		    (unsigned)count);
+		len -= count;
+		m->m_len += count;
+		n->m_len -= count;
+		space -= count;
+		if (n->m_len)
+			n->m_data += count;
+		else
+			n = m_free(n);
+	} while (len > 0 && n);
+	if (len > 0) {
+		(void) m_free(m);
+		goto bad;
+	}
+	m->m_next = n;
+	return (m);
+ bad:
+	m_freem(n);
+	MSFail++;
+	return (NULL);
+}
+
+/*
+ * Partition an mbuf chain in two pieces, returning the tail --
+ * all but the first len0 bytes.  In case of failure, it returns NULL and
+ * attempts to restore the chain to its original state.
+ *
+ * Note that the resulting mbufs might be read-only, because the new
+ * mbuf can end up sharing an mbuf cluster with the original mbuf if
+ * the "breaking point" happens to lie within a cluster mbuf. Use the
+ * M_WRITABLE() macro to check for this case.
+ */
+struct mbuf *
+m_split(struct mbuf *m0, int len0, int wait)
+{
+	struct mbuf *m, *n;
+	u_int len = len0, remain;
+
+	MBUF_CHECKSLEEP(wait);
+	for (m = m0; m && len > m->m_len; m = m->m_next)
+		len -= m->m_len;
+	if (m == NULL)
+		return (NULL);
+	remain = m->m_len - len;
+	if (m0->m_flags & M_PKTHDR) {
+		MGETHDR(n, wait, m0->m_type);
+		if (n == NULL)
+			return (NULL);
+		n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
+		n->m_pkthdr.len = m0->m_pkthdr.len - len0;
+		m0->m_pkthdr.len = len0;
+		if (m->m_flags & M_EXT)
+			goto extpacket;
+		if (remain > MHLEN) {
+			/* m can't be the lead packet */
+			MH_ALIGN(n, 0);
+			n->m_next = m_split(m, len, wait);
+			if (n->m_next == NULL) {
+				(void) m_free(n);
+				return (NULL);
+			} else {
+				n->m_len = 0;
+				return (n);
+			}
+		} else
+			MH_ALIGN(n, remain);
+	} else if (remain == 0) {
+		n = m->m_next;
+		m->m_next = NULL;
+		return (n);
+	} else {
+		MGET(n, wait, m->m_type);
+		if (n == NULL)
+			return (NULL);
+		M_ALIGN(n, remain);
+	}
+extpacket:
+	if (m->m_flags & M_EXT) {
+		n->m_data = m->m_data + len;
+		mb_dupcl(n, m);
+	} else {
+		bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain);
+	}
+	n->m_len = remain;
+	m->m_len = len;
+	n->m_next = m->m_next;
+	m->m_next = NULL;
+	return (n);
+}
+/*
+ * Routine to copy from device local memory into mbufs.
+ * Note that `off' argument is offset into first mbuf of target chain from
+ * which to begin copying the data to.
+ */
+struct mbuf *
+m_devget(char *buf, int totlen, int off, struct ifnet *ifp,
+    void (*copy)(char *from, caddr_t to, u_int len))
+{
+	struct mbuf *m;
+	struct mbuf *top = NULL, **mp = &top;
+	int len;
+
+	if (off < 0 || off > MHLEN)
+		return (NULL);
+
+	while (totlen > 0) {
+		if (top == NULL) {	/* First one, must be PKTHDR */
+			if (totlen + off >= MINCLSIZE) {
+				m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
+				len = MCLBYTES;
+			} else {
+				m = m_gethdr(M_DONTWAIT, MT_DATA);
+				len = MHLEN;
+
+				/* Place initial small packet/header at end of mbuf */
+				if (m && totlen + off + max_linkhdr <= MLEN) {
+					m->m_data += max_linkhdr;
+					len -= max_linkhdr;
+				}
+			}
+			if (m == NULL)
+				return NULL;
+			m->m_pkthdr.rcvif = ifp;
+			m->m_pkthdr.len = totlen;
+		} else {
+			if (totlen + off >= MINCLSIZE) {
+				m = m_getcl(M_DONTWAIT, MT_DATA, 0);
+				len = MCLBYTES;
+			} else {
+				m = m_get(M_DONTWAIT, MT_DATA);
+				len = MLEN;
+			}
+			if (m == NULL) {
+				m_freem(top);
+				return NULL;
+			}
+		}
+		if (off) {
+			m->m_data += off;
+			len -= off;
+			off = 0;
+		}
+		m->m_len = len = min(totlen, len);
+		if (copy)
+			copy(buf, mtod(m, caddr_t), (u_int)len);
+		else
+			bcopy(buf, mtod(m, caddr_t), (u_int)len);
+		buf += len;
+		*mp = m;
+		mp = &m->m_next;
+		totlen -= len;
+	}
+	return (top);
+}
+
+/*
+ * Copy data from a buffer back into the indicated mbuf chain,
+ * starting "off" bytes from the beginning, extending the mbuf
+ * chain if necessary.
+ */
+void
+m_copyback(struct mbuf *m0, int off, int len, c_caddr_t cp)
+{
+	int mlen;
+	struct mbuf *m = m0, *n;
+	int totlen = 0;
+
+	if (m0 == NULL)
+		return;
+	while (off > (mlen = m->m_len)) {
+		off -= mlen;
+		totlen += mlen;
+		if (m->m_next == NULL) {
+			n = m_get(M_DONTWAIT, m->m_type);
+			if (n == NULL)
+				goto out;
+			bzero(mtod(n, caddr_t), MLEN);
+			n->m_len = min(MLEN, len + off);
+			m->m_next = n;
+		}
+		m = m->m_next;
+	}
+	while (len > 0) {
+		if (m->m_next == NULL && (len > m->m_len - off)) {
+			m->m_len += min(len - (m->m_len - off),
+			    M_TRAILINGSPACE(m));
+		}
+		mlen = min (m->m_len - off, len);
+		bcopy(cp, off + mtod(m, caddr_t), (u_int)mlen);
+		cp += mlen;
+		len -= mlen;
+		mlen += off;
+		off = 0;
+		totlen += mlen;
+		if (len == 0)
+			break;
+		if (m->m_next == NULL) {
+			n = m_get(M_DONTWAIT, m->m_type);
+			if (n == NULL)
+				break;
+			n->m_len = min(MLEN, len);
+			m->m_next = n;
+		}
+		m = m->m_next;
+	}
+out:	if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
+		m->m_pkthdr.len = totlen;
+}
+
+/*
+ * Append the specified data to the indicated mbuf chain,
+ * Extend the mbuf chain if the new data does not fit in
+ * existing space.
+ *
+ * Return 1 if able to complete the job; otherwise 0.
+ */
+int
+m_append(struct mbuf *m0, int len, c_caddr_t cp)
+{
+	struct mbuf *m, *n;
+	int remainder, space;
+
+	for (m = m0; m->m_next != NULL; m = m->m_next)
+		;
+	remainder = len;
+	space = M_TRAILINGSPACE(m);
+	if (space > 0) {
+		/*
+		 * Copy into available space.
+		 */
+		if (space > remainder)
+			space = remainder;
+		bcopy(cp, mtod(m, caddr_t) + m->m_len, space);
+		m->m_len += space;
+		cp += space, remainder -= space;
+	}
+	while (remainder > 0) {
+		/*
+		 * Allocate a new mbuf; could check space
+		 * and allocate a cluster instead.
+		 */
+		n = m_get(M_DONTWAIT, m->m_type);
+		if (n == NULL)
+			break;
+		n->m_len = min(MLEN, remainder);
+		bcopy(cp, mtod(n, caddr_t), n->m_len);
+		cp += n->m_len, remainder -= n->m_len;
+		m->m_next = n;
+		m = n;
+	}
+	if (m0->m_flags & M_PKTHDR)
+		m0->m_pkthdr.len += len - remainder;
+	return (remainder == 0);
+}
+
+/*
+ * Apply function f to the data in an mbuf chain starting "off" bytes from
+ * the beginning, continuing for "len" bytes.
+ */
+int
+m_apply(struct mbuf *m, int off, int len,
+    int (*f)(void *, void *, u_int), void *arg)
+{
+	u_int count;
+	int rval;
+
+	KASSERT(off >= 0, ("m_apply, negative off %d", off));
+	KASSERT(len >= 0, ("m_apply, negative len %d", len));
+	while (off > 0) {
+		KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
+		if (off < m->m_len)
+			break;
+		off -= m->m_len;
+		m = m->m_next;
+	}
+	while (len > 0) {
+		KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
+		count = min(m->m_len - off, len);
+		rval = (*f)(arg, mtod(m, caddr_t) + off, count);
+		if (rval)
+			return (rval);
+		len -= count;
+		off = 0;
+		m = m->m_next;
+	}
+	return (0);
+}
+
+/*
+ * Return a pointer to mbuf/offset of location in mbuf chain.
+ */
+struct mbuf *
+m_getptr(struct mbuf *m, int loc, int *off)
+{
+
+	while (loc >= 0) {
+		/* Normal end of search. */
+		if (m->m_len > loc) {
+			*off = loc;
+			return (m);
+		} else {
+			loc -= m->m_len;
+			if (m->m_next == NULL) {
+				if (loc == 0) {
+					/* Point at the end of valid data. */
+					*off = m->m_len;
+					return (m);
+				}
+				return (NULL);
+			}
+			m = m->m_next;
+		}
+	}
+	return (NULL);
+}
+
+void
+m_print(const struct mbuf *m, int maxlen)
+{
+	int len;
+	int pdata;
+	const struct mbuf *m2;
+
+	if (m->m_flags & M_PKTHDR)
+		len = m->m_pkthdr.len;
+	else
+		len = -1;
+	m2 = m;
+	while (m2 != NULL && (len == -1 || len)) {
+		pdata = m2->m_len;
+		if (maxlen != -1 && pdata > maxlen)
+			pdata = maxlen;
+		printf("mbuf: %p len: %d, next: %p, %b%s", m2, m2->m_len,
+		    m2->m_next, m2->m_flags, "\20\20freelist\17skipfw"
+		    "\11proto5\10proto4\7proto3\6proto2\5proto1\4rdonly"
+		    "\3eor\2pkthdr\1ext", pdata ? "" : "\n");
+		if (pdata)
+			printf(", %*D\n", pdata, (u_char *)m2->m_data, "-");
+		if (len != -1)
+			len -= m2->m_len;
+		m2 = m2->m_next;
+	}
+	if (len > 0)
+		printf("%d bytes unaccounted for.\n", len);
+	return;
+}
+
+u_int
+m_fixhdr(struct mbuf *m0)
+{
+	u_int len;
+
+	len = m_length(m0, NULL);
+	m0->m_pkthdr.len = len;
+	return (len);
+}
+
+u_int
+m_length(struct mbuf *m0, struct mbuf **last)
+{
+	struct mbuf *m;
+	u_int len;
+
+	len = 0;
+	for (m = m0; m != NULL; m = m->m_next) {
+		len += m->m_len;
+		if (m->m_next == NULL)
+			break;
+	}
+	if (last != NULL)
+		*last = m;
+	return (len);
+}
+
+/*
+ * Defragment a mbuf chain, returning the shortest possible
+ * chain of mbufs and clusters.  If allocation fails and
+ * this cannot be completed, NULL will be returned, but
+ * the passed in chain will be unchanged.  Upon success,
+ * the original chain will be freed, and the new chain
+ * will be returned.
+ *
+ * If a non-packet header is passed in, the original
+ * mbuf (chain?) will be returned unharmed.
+ */
+struct mbuf *
+m_defrag(struct mbuf *m0, int how)
+{
+	struct mbuf *m_new = NULL, *m_final = NULL;
+	int progress = 0, length;
+
+	MBUF_CHECKSLEEP(how);
+	if (!(m0->m_flags & M_PKTHDR))
+		return (m0);
+
+	m_fixhdr(m0); /* Needed sanity check */
+
+#ifdef MBUF_STRESS_TEST
+	if (m_defragrandomfailures) {
+		int temp = arc4random() & 0xff;
+		if (temp == 0xba)
+			goto nospace;
+	}
+#endif
+
+	if (m0->m_pkthdr.len > MHLEN)
+		m_final = m_getcl(how, MT_DATA, M_PKTHDR);
+	else
+		m_final = m_gethdr(how, MT_DATA);
+
+	if (m_final == NULL)
+		goto nospace;
+
+	if (m_dup_pkthdr(m_final, m0, how) == 0)
+		goto nospace;
+
+	m_new = m_final;
+
+	while (progress < m0->m_pkthdr.len) {
+		length = m0->m_pkthdr.len - progress;
+		if (length > MCLBYTES)
+			length = MCLBYTES;
+
+		if (m_new == NULL) {
+			if (length > MLEN)
+				m_new = m_getcl(how, MT_DATA, 0);
+			else
+				m_new = m_get(how, MT_DATA);
+			if (m_new == NULL)
+				goto nospace;
+		}
+
+		m_copydata(m0, progress, length, mtod(m_new, caddr_t));
+		progress += length;
+		m_new->m_len = length;
+		if (m_new != m_final)
+			m_cat(m_final, m_new);
+		m_new = NULL;
+	}
+#ifdef MBUF_STRESS_TEST
+	if (m0->m_next == NULL)
+		m_defraguseless++;
+#endif
+	m_freem(m0);
+	m0 = m_final;
+#ifdef MBUF_STRESS_TEST
+	m_defragpackets++;
+	m_defragbytes += m0->m_pkthdr.len;
+#endif
+	return (m0);
+nospace:
+#ifdef MBUF_STRESS_TEST
+	m_defragfailure++;
+#endif
+	if (m_final)
+		m_freem(m_final);
+	return (NULL);
+}
+
+/*
+ * Defragment an mbuf chain, returning at most maxfrags separate
+ * mbufs+clusters.  If this is not possible NULL is returned and
+ * the original mbuf chain is left in it's present (potentially
+ * modified) state.  We use two techniques: collapsing consecutive
+ * mbufs and replacing consecutive mbufs by a cluster.
+ *
+ * NB: this should really be named m_defrag but that name is taken
+ */
+struct mbuf *
+m_collapse(struct mbuf *m0, int how, int maxfrags)
+{
+	struct mbuf *m, *n, *n2, **prev;
+	u_int curfrags;
+
+	/*
+	 * Calculate the current number of frags.
+	 */
+	curfrags = 0;
+	for (m = m0; m != NULL; m = m->m_next)
+		curfrags++;
+	/*
+	 * First, try to collapse mbufs.  Note that we always collapse
+	 * towards the front so we don't need to deal with moving the
+	 * pkthdr.  This may be suboptimal if the first mbuf has much
+	 * less data than the following.
+	 */
+	m = m0;
+again:
+	for (;;) {
+		n = m->m_next;
+		if (n == NULL)
+			break;
+		if ((m->m_flags & M_RDONLY) == 0 &&
+		    n->m_len < M_TRAILINGSPACE(m)) {
+			bcopy(mtod(n, void *), mtod(m, char *) + m->m_len,
+				n->m_len);
+			m->m_len += n->m_len;
+			m->m_next = n->m_next;
+			m_free(n);
+			if (--curfrags <= maxfrags)
+				return m0;
+		} else
+			m = n;
+	}
+	KASSERT(maxfrags > 1,
+		("maxfrags %u, but normal collapse failed", maxfrags));
+	/*
+	 * Collapse consecutive mbufs to a cluster.
+	 */
+	prev = &m0->m_next;		/* NB: not the first mbuf */
+	while ((n = *prev) != NULL) {
+		if ((n2 = n->m_next) != NULL &&
+		    n->m_len + n2->m_len < MCLBYTES) {
+			m = m_getcl(how, MT_DATA, 0);
+			if (m == NULL)
+				goto bad;
+			bcopy(mtod(n, void *), mtod(m, void *), n->m_len);
+			bcopy(mtod(n2, void *), mtod(m, char *) + n->m_len,
+				n2->m_len);
+			m->m_len = n->m_len + n2->m_len;
+			m->m_next = n2->m_next;
+			*prev = m;
+			m_free(n);
+			m_free(n2);
+			if (--curfrags <= maxfrags)	/* +1 cl -2 mbufs */
+				return m0;
+			/*
+			 * Still not there, try the normal collapse
+			 * again before we allocate another cluster.
+			 */
+			goto again;
+		}
+		prev = &n->m_next;
+	}
+	/*
+	 * No place where we can collapse to a cluster; punt.
+	 * This can occur if, for example, you request 2 frags
+	 * but the packet requires that both be clusters (we
+	 * never reallocate the first mbuf to avoid moving the
+	 * packet header).
+	 */
+bad:
+	return NULL;
+}
+
+#ifdef MBUF_STRESS_TEST
+
+/*
+ * Fragment an mbuf chain.  There's no reason you'd ever want to do
+ * this in normal usage, but it's great for stress testing various
+ * mbuf consumers.
+ *
+ * If fragmentation is not possible, the original chain will be
+ * returned.
+ *
+ * Possible length values:
+ * 0	 no fragmentation will occur
+ * > 0	each fragment will be of the specified length
+ * -1	each fragment will be the same random value in length
+ * -2	each fragment's length will be entirely random
+ * (Random values range from 1 to 256)
+ */
+struct mbuf *
+m_fragment(struct mbuf *m0, int how, int length)
+{
+	struct mbuf *m_new = NULL, *m_final = NULL;
+	int progress = 0;
+
+	if (!(m0->m_flags & M_PKTHDR))
+		return (m0);
+
+	if ((length == 0) || (length < -2))
+		return (m0);
+
+	m_fixhdr(m0); /* Needed sanity check */
+
+	m_final = m_getcl(how, MT_DATA, M_PKTHDR);
+
+	if (m_final == NULL)
+		goto nospace;
+
+	if (m_dup_pkthdr(m_final, m0, how) == 0)
+		goto nospace;
+
+	m_new = m_final;
+
+	if (length == -1)
+		length = 1 + (arc4random() & 255);
+
+	while (progress < m0->m_pkthdr.len) {
+		int fraglen;
+
+		if (length > 0)
+			fraglen = length;
+		else
+			fraglen = 1 + (arc4random() & 255);
+		if (fraglen > m0->m_pkthdr.len - progress)
+			fraglen = m0->m_pkthdr.len - progress;
+
+		if (fraglen > MCLBYTES)
+			fraglen = MCLBYTES;
+
+		if (m_new == NULL) {
+			m_new = m_getcl(how, MT_DATA, 0);
+			if (m_new == NULL)
+				goto nospace;
+		}
+
+		m_copydata(m0, progress, fraglen, mtod(m_new, caddr_t));
+		progress += fraglen;
+		m_new->m_len = fraglen;
+		if (m_new != m_final)
+			m_cat(m_final, m_new);
+		m_new = NULL;
+	}
+	m_freem(m0);
+	m0 = m_final;
+	return (m0);
+nospace:
+	if (m_final)
+		m_freem(m_final);
+	/* Return the original chain on failure */
+	return (m0);
+}
+
+#endif
+
+/*
+ * Copy the contents of uio into a properly sized mbuf chain.
+ */
+struct mbuf *
+m_uiotombuf(struct uio *uio, int how, int len, int align, int flags)
+{
+	struct mbuf *m, *mb;
+	int error, length, total;
+	int progress = 0;
+
+	/*
+	 * len can be zero or an arbitrary large value bound by
+	 * the total data supplied by the uio.
+	 */
+	if (len > 0)
+		total = min(uio->uio_resid, len);
+	else
+		total = uio->uio_resid;
+
+	/*
+	 * The smallest unit returned by m_getm2() is a single mbuf
+	 * with pkthdr.  We can't align past it.
+	 */
+	if (align >= MHLEN)
+		return (NULL);
+
+	/*
+	 * Give us the full allocation or nothing.
+	 * If len is zero return the smallest empty mbuf.
+	 */
+	m = m_getm2(NULL, max(total + align, 1), how, MT_DATA, flags);
+	if (m == NULL)
+		return (NULL);
+	m->m_data += align;
+
+	/* Fill all mbufs with uio data and update header information. */
+	for (mb = m; mb != NULL; mb = mb->m_next) {
+		length = min(M_TRAILINGSPACE(mb), total - progress);
+
+		error = uiomove(mtod(mb, void *), length, uio);
+		if (error) {
+			m_freem(m);
+			return (NULL);
+		}
+
+		mb->m_len = length;
+		progress += length;
+		if (flags & M_PKTHDR)
+			m->m_pkthdr.len += length;
+	}
+	KASSERT(progress == total, ("%s: progress != total", __func__));
+
+	return (m);
+}
+
+/*
+ * Copy an mbuf chain into a uio limited by len if set.
+ */
+int
+m_mbuftouio(struct uio *uio, struct mbuf *m, int len)
+{
+	int error, length, total;
+	int progress = 0;
+
+	if (len > 0)
+		total = min(uio->uio_resid, len);
+	else
+		total = uio->uio_resid;
+
+	/* Fill the uio with data from the mbufs. */
+	for (; m != NULL; m = m->m_next) {
+		length = min(m->m_len, total - progress);
+
+		error = uiomove(mtod(m, void *), length, uio);
+		if (error)
+			return (error);
+
+		progress += length;
+	}
+
+	return (0);
+}
+
+/*
+ * Set the m_data pointer of a newly-allocated mbuf
+ * to place an object of the specified size at the
+ * end of the mbuf, longword aligned.
+ */
+void
+m_align(struct mbuf *m, int len)
+{
+	int adjust;
+
+	if (m->m_flags & M_EXT)
+		adjust = m->m_ext.ext_size - len;
+	else if (m->m_flags & M_PKTHDR)
+		adjust = MHLEN - len;
+	else
+		adjust = MLEN - len;
+	m->m_data += adjust &~ (sizeof(long)-1);
+}
+
+/*
+ * Create a writable copy of the mbuf chain.  While doing this
+ * we compact the chain with a goal of producing a chain with
+ * at most two mbufs.  The second mbuf in this chain is likely
+ * to be a cluster.  The primary purpose of this work is to create
+ * a writable packet for encryption, compression, etc.  The
+ * secondary goal is to linearize the data so the data can be
+ * passed to crypto hardware in the most efficient manner possible.
+ */
+struct mbuf *
+m_unshare(struct mbuf *m0, int how)
+{
+	struct mbuf *m, *mprev;
+	struct mbuf *n, *mfirst, *mlast;
+	int len, off;
+
+	mprev = NULL;
+	for (m = m0; m != NULL; m = mprev->m_next) {
+		/*
+		 * Regular mbufs are ignored unless there's a cluster
+		 * in front of it that we can use to coalesce.  We do
+		 * the latter mainly so later clusters can be coalesced
+		 * also w/o having to handle them specially (i.e. convert
+		 * mbuf+cluster -> cluster).  This optimization is heavily
+		 * influenced by the assumption that we're running over
+		 * Ethernet where MCLBYTES is large enough that the max
+		 * packet size will permit lots of coalescing into a
+		 * single cluster.  This in turn permits efficient
+		 * crypto operations, especially when using hardware.
+		 */
+		if ((m->m_flags & M_EXT) == 0) {
+			if (mprev && (mprev->m_flags & M_EXT) &&
+			    m->m_len <= M_TRAILINGSPACE(mprev)) {
+				/* XXX: this ignores mbuf types */
+				memcpy(mtod(mprev, caddr_t) + mprev->m_len,
+				       mtod(m, caddr_t), m->m_len);
+				mprev->m_len += m->m_len;
+				mprev->m_next = m->m_next;	/* unlink from chain */
+				m_free(m);			/* reclaim mbuf */
+#if 0
+				newipsecstat.ips_mbcoalesced++;
+#endif
+			} else {
+				mprev = m;
+			}
+			continue;
+		}
+		/*
+		 * Writable mbufs are left alone (for now).
+		 */
+		if (M_WRITABLE(m)) {
+			mprev = m;
+			continue;
+		}
+
+		/*
+		 * Not writable, replace with a copy or coalesce with
+		 * the previous mbuf if possible (since we have to copy
+		 * it anyway, we try to reduce the number of mbufs and
+		 * clusters so that future work is easier).
+		 */
+		KASSERT(m->m_flags & M_EXT, ("m_flags 0x%x", m->m_flags));
+		/* NB: we only coalesce into a cluster or larger */
+		if (mprev != NULL && (mprev->m_flags & M_EXT) &&
+		    m->m_len <= M_TRAILINGSPACE(mprev)) {
+			/* XXX: this ignores mbuf types */
+			memcpy(mtod(mprev, caddr_t) + mprev->m_len,
+			       mtod(m, caddr_t), m->m_len);
+			mprev->m_len += m->m_len;
+			mprev->m_next = m->m_next;	/* unlink from chain */
+			m_free(m);			/* reclaim mbuf */
+#if 0
+			newipsecstat.ips_clcoalesced++;
+#endif
+			continue;
+		}
+
+		/*
+		 * Allocate new space to hold the copy...
+		 */
+		/* XXX why can M_PKTHDR be set past the first mbuf? */
+		if (mprev == NULL && (m->m_flags & M_PKTHDR)) {
+			/*
+			 * NB: if a packet header is present we must
+			 * allocate the mbuf separately from any cluster
+			 * because M_MOVE_PKTHDR will smash the data
+			 * pointer and drop the M_EXT marker.
+			 */
+			MGETHDR(n, how, m->m_type);
+			if (n == NULL) {
+				m_freem(m0);
+				return (NULL);
+			}
+			M_MOVE_PKTHDR(n, m);
+			MCLGET(n, how);
+			if ((n->m_flags & M_EXT) == 0) {
+				m_free(n);
+				m_freem(m0);
+				return (NULL);
+			}
+		} else {
+			n = m_getcl(how, m->m_type, m->m_flags);
+			if (n == NULL) {
+				m_freem(m0);
+				return (NULL);
+			}
+		}
+		/*
+		 * ... and copy the data.  We deal with jumbo mbufs
+		 * (i.e. m_len > MCLBYTES) by splitting them into
+		 * clusters.  We could just malloc a buffer and make
+		 * it external but too many device drivers don't know
+		 * how to break up the non-contiguous memory when
+		 * doing DMA.
+		 */
+		len = m->m_len;
+		off = 0;
+		mfirst = n;
+		mlast = NULL;
+		for (;;) {
+			int cc = min(len, MCLBYTES);
+			memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, cc);
+			n->m_len = cc;
+			if (mlast != NULL)
+				mlast->m_next = n;
+			mlast = n;
+#if 0
+			newipsecstat.ips_clcopied++;
+#endif
+
+			len -= cc;
+			if (len <= 0)
+				break;
+			off += cc;
+
+			n = m_getcl(how, m->m_type, m->m_flags);
+			if (n == NULL) {
+				m_freem(mfirst);
+				m_freem(m0);
+				return (NULL);
+			}
+		}
+		n->m_next = m->m_next;
+		if (mprev == NULL)
+			m0 = mfirst;		/* new head of chain */
+		else
+			mprev->m_next = mfirst;	/* replace old mbuf */
+		m_free(m);			/* release old mbuf */
+		mprev = mfirst;
+	}
+	return (m0);
+}
+
+#ifdef MBUF_PROFILING
+
+#define MP_BUCKETS 32 /* don't just change this as things may overflow.*/
+struct mbufprofile {
+	uintmax_t wasted[MP_BUCKETS];
+	uintmax_t used[MP_BUCKETS];
+	uintmax_t segments[MP_BUCKETS];
+} mbprof;
+
+#define MP_MAXDIGITS 21	/* strlen("16,000,000,000,000,000,000") == 21 */
+#define MP_NUMLINES 6
+#define MP_NUMSPERLINE 16
+#define MP_EXTRABYTES 64	/* > strlen("used:\nwasted:\nsegments:\n") */
+/* work out max space needed and add a bit of spare space too */
+#define MP_MAXLINE ((MP_MAXDIGITS+1) * MP_NUMSPERLINE)
+#define MP_BUFSIZE ((MP_MAXLINE * MP_NUMLINES) + 1 + MP_EXTRABYTES)
+
+char mbprofbuf[MP_BUFSIZE];
+
+void
+m_profile(struct mbuf *m)
+{
+	int segments = 0;
+	int used = 0;
+	int wasted = 0;
+
+	while (m) {
+		segments++;
+		used += m->m_len;
+		if (m->m_flags & M_EXT) {
+			wasted += MHLEN - sizeof(m->m_ext) +
+			    m->m_ext.ext_size - m->m_len;
+		} else {
+			if (m->m_flags & M_PKTHDR)
+				wasted += MHLEN - m->m_len;
+			else
+				wasted += MLEN - m->m_len;
+		}
+		m = m->m_next;
+	}
+	/* be paranoid.. it helps */
+	if (segments > MP_BUCKETS - 1)
+		segments = MP_BUCKETS - 1;
+	if (used > 100000)
+		used = 100000;
+	if (wasted > 100000)
+		wasted = 100000;
+	/* store in the appropriate bucket */
+	/* don't bother locking. if it's slightly off, so what? */
+	mbprof.segments[segments]++;
+	mbprof.used[fls(used)]++;
+	mbprof.wasted[fls(wasted)]++;
+}
+
+static void
+mbprof_textify(void)
+{
+	int offset;
+	char *c;
+	u_int64_t *p;
+
+
+	p = &mbprof.wasted[0];
+	c = mbprofbuf;
+	offset = snprintf(c, MP_MAXLINE + 10,
+	    "wasted:\n"
+	    "%ju %ju %ju %ju %ju %ju %ju %ju "
+	    "%ju %ju %ju %ju %ju %ju %ju %ju\n",
+	    p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
+	    p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
+#ifdef BIG_ARRAY
+	p = &mbprof.wasted[16];
+	c += offset;
+	offset = snprintf(c, MP_MAXLINE,
+	    "%ju %ju %ju %ju %ju %ju %ju %ju "
+	    "%ju %ju %ju %ju %ju %ju %ju %ju\n",
+	    p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
+	    p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
+#endif
+	p = &mbprof.used[0];
+	c += offset;
+	offset = snprintf(c, MP_MAXLINE + 10,
+	    "used:\n"
+	    "%ju %ju %ju %ju %ju %ju %ju %ju "
+	    "%ju %ju %ju %ju %ju %ju %ju %ju\n",
+	    p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
+	    p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
+#ifdef BIG_ARRAY
+	p = &mbprof.used[16];
+	c += offset;
+	offset = snprintf(c, MP_MAXLINE,
+	    "%ju %ju %ju %ju %ju %ju %ju %ju "
+	    "%ju %ju %ju %ju %ju %ju %ju %ju\n",
+	    p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
+	    p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
+#endif
+	p = &mbprof.segments[0];
+	c += offset;
+	offset = snprintf(c, MP_MAXLINE + 10,
+	    "segments:\n"
+	    "%ju %ju %ju %ju %ju %ju %ju %ju "
+	    "%ju %ju %ju %ju %ju %ju %ju %ju\n",
+	    p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
+	    p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
+#ifdef BIG_ARRAY
+	p = &mbprof.segments[16];
+	c += offset;
+	offset = snprintf(c, MP_MAXLINE,
+	    "%ju %ju %ju %ju %ju %ju %ju %ju "
+	    "%ju %ju %ju %ju %ju %ju %ju %jju",
+	    p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
+	    p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
+#endif
+}
+
+static int
+mbprof_handler(SYSCTL_HANDLER_ARGS)
+{
+	int error;
+
+	mbprof_textify();
+	error = SYSCTL_OUT(req, mbprofbuf, strlen(mbprofbuf) + 1);
+	return (error);
+}
+
+static int
+mbprof_clr_handler(SYSCTL_HANDLER_ARGS)
+{
+	int clear, error;
+
+	clear = 0;
+	error = sysctl_handle_int(oidp, &clear, 0, req);
+	if (error || !req->newptr)
+		return (error);
+
+	if (clear) {
+		bzero(&mbprof, sizeof(mbprof));
+	}
+
+	return (error);
+}
+
+
+SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofile, CTLTYPE_STRING|CTLFLAG_RD,
+	    NULL, 0, mbprof_handler, "A", "mbuf profiling statistics");
+
+SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofileclr, CTLTYPE_INT|CTLFLAG_RW,
+	    NULL, 0, mbprof_clr_handler, "I", "clear mbuf profiling statistics");
+#endif
+