2 * Copyright (c) 1982, 1986, 1988, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
35 #include "opt_param.h"
36 #include "opt_mbuf_stress_test.h"
37 #include "opt_mbuf_profiling.h"
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/kernel.h>
42 #include <sys/limits.h>
44 #include <sys/malloc.h>
46 #include <sys/sysctl.h>
47 #include <sys/domain.h>
48 #include <sys/protosw.h>
55 #ifdef MBUF_STRESS_TEST
60 int m_defragrandomfailures;
64 * sysctl(8) exported objects
66 SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RD,
67 &max_linkhdr, 0, "Size of largest link layer header");
68 SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RD,
69 &max_protohdr, 0, "Size of largest protocol layer header");
70 SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RD,
71 &max_hdr, 0, "Size of largest link plus protocol header");
72 SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RD,
73 &max_datalen, 0, "Minimum space left in mbuf after max_hdr");
74 #ifdef MBUF_STRESS_TEST
75 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD,
76 &m_defragpackets, 0, "");
77 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD,
78 &m_defragbytes, 0, "");
79 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD,
80 &m_defraguseless, 0, "");
81 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD,
82 &m_defragfailure, 0, "");
83 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW,
84 &m_defragrandomfailures, 0, "");
88 * m_get2() allocates minimum mbuf that would fit "size" argument.
91 m_get2(int how, short type, int flags, int size)
100 if (size <= MHLEN || (size <= MLEN && (flags & M_PKTHDR) == 0))
101 return (uma_zalloc_arg(zone_mbuf, &args, how));
102 if (size <= MCLBYTES)
103 return (uma_zalloc_arg(zone_pack, &args, how));
104 if (size > MJUM16BYTES)
107 m = uma_zalloc_arg(zone_mbuf, &args, how);
111 #if MJUMPAGESIZE != MCLBYTES
112 if (size <= MJUMPAGESIZE)
116 if (size <= MJUM9BYTES)
121 n = uma_zalloc_arg(zone, m, how);
123 uma_zfree(zone_mbuf, m);
131 * m_getjcl() returns an mbuf with a cluster of the specified size attached.
132 * For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
135 m_getjcl(int how, short type, int flags, int size)
141 if (size == MCLBYTES)
142 return m_getcl(how, type, flags);
147 m = uma_zalloc_arg(zone_mbuf, &args, how);
151 zone = m_getzone(size);
152 n = uma_zalloc_arg(zone, m, how);
154 uma_zfree(zone_mbuf, m);
161 * Allocate a given length worth of mbufs and/or clusters (whatever fits
162 * best) and return a pointer to the top of the allocated chain. If an
163 * existing mbuf chain is provided, then we will append the new chain
164 * to the existing one but still return the top of the newly allocated
168 m_getm2(struct mbuf *m, int len, int how, short type, int flags)
170 struct mbuf *mb, *nm = NULL, *mtail = NULL;
172 KASSERT(len >= 0, ("%s: len is < 0", __func__));
174 /* Validate flags. */
175 flags &= (M_PKTHDR | M_EOR);
177 /* Packet header mbuf must be first in chain. */
178 if ((flags & M_PKTHDR) && m != NULL)
181 /* Loop and append maximum sized mbufs to the chain tail. */
184 mb = m_getjcl(how, type, (flags & M_PKTHDR),
186 else if (len >= MINCLSIZE)
187 mb = m_getcl(how, type, (flags & M_PKTHDR));
188 else if (flags & M_PKTHDR)
189 mb = m_gethdr(how, type);
191 mb = m_get(how, type);
193 /* Fail the whole operation if one mbuf can't be allocated. */
201 len -= (mb->m_flags & M_EXT) ? mb->m_ext.ext_size :
202 ((mb->m_flags & M_PKTHDR) ? MHLEN : MLEN);
208 flags &= ~M_PKTHDR; /* Only valid on the first mbuf. */
211 mtail->m_flags |= M_EOR; /* Only valid on the last mbuf. */
213 /* If mbuf was supplied, append new chain to the end of it. */
215 for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next)
218 mtail->m_flags &= ~M_EOR;
226 * Free an entire chain of mbufs and associated external buffers, if
230 m_freem(struct mbuf *mb)
238 * Configure a provided mbuf to refer to the provided external storage
239 * buffer and setup a reference count for said buffer. If the setting
240 * up of the reference count fails, the M_EXT bit will not be set. If
241 * successfull, the M_EXT bit is set in the mbuf's flags.
244 * mb The existing mbuf to which to attach the provided buffer.
245 * buf The address of the provided external storage buffer.
246 * size The size of the provided buffer.
247 * freef A pointer to a routine that is responsible for freeing the
248 * provided external storage buffer.
249 * args A pointer to an argument structure (of any type) to be passed
250 * to the provided freef routine (may be NULL).
251 * flags Any other flags to be passed to the provided mbuf.
252 * type The type that the external storage buffer should be
259 m_extadd(struct mbuf *mb, caddr_t buf, u_int size,
260 void (*freef)(void *, void *), void *arg1, void *arg2, int flags, int type)
262 KASSERT(type != EXT_CLUSTER, ("%s: EXT_CLUSTER not allowed", __func__));
264 if (type != EXT_EXTREF)
265 mb->m_ext.ref_cnt = (u_int *)uma_zalloc(zone_ext_refcnt, M_NOWAIT);
266 if (mb->m_ext.ref_cnt != NULL) {
267 *(mb->m_ext.ref_cnt) = 1;
268 mb->m_flags |= (M_EXT | flags);
269 mb->m_ext.ext_buf = buf;
270 mb->m_data = mb->m_ext.ext_buf;
271 mb->m_ext.ext_size = size;
272 mb->m_ext.ext_free = freef;
273 mb->m_ext.ext_arg1 = arg1;
274 mb->m_ext.ext_arg2 = arg2;
275 mb->m_ext.ext_type = type;
280 * Non-directly-exported function to clean up after mbufs with M_EXT
281 * storage attached to them if the reference count hits 1.
284 mb_free_ext(struct mbuf *m)
288 KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
289 KASSERT(m->m_ext.ref_cnt != NULL, ("%s: ref_cnt not set", __func__));
293 * check if the header is embedded in the cluster
295 skipmbuf = (m->m_flags & M_NOFREE);
297 /* Free attached storage if this mbuf is the only reference to it. */
298 if (*(m->m_ext.ref_cnt) == 1 ||
299 atomic_fetchadd_int(m->m_ext.ref_cnt, -1) == 1) {
300 switch (m->m_ext.ext_type) {
301 case EXT_PACKET: /* The packet zone is special. */
302 if (*(m->m_ext.ref_cnt) == 0)
303 *(m->m_ext.ref_cnt) = 1;
304 uma_zfree(zone_pack, m);
305 return; /* Job done. */
307 uma_zfree(zone_clust, m->m_ext.ext_buf);
310 uma_zfree(zone_jumbop, m->m_ext.ext_buf);
313 uma_zfree(zone_jumbo9, m->m_ext.ext_buf);
316 uma_zfree(zone_jumbo16, m->m_ext.ext_buf);
322 *(m->m_ext.ref_cnt) = 0;
323 uma_zfree(zone_ext_refcnt, __DEVOLATILE(u_int *,
327 KASSERT(m->m_ext.ext_free != NULL,
328 ("%s: ext_free not set", __func__));
329 (*(m->m_ext.ext_free))(m->m_ext.ext_arg1,
333 KASSERT(m->m_ext.ext_type == 0,
334 ("%s: unknown ext_type", __func__));
341 * Free this mbuf back to the mbuf zone with all m_ext
342 * information purged.
344 m->m_ext.ext_buf = NULL;
345 m->m_ext.ext_free = NULL;
346 m->m_ext.ext_arg1 = NULL;
347 m->m_ext.ext_arg2 = NULL;
348 m->m_ext.ref_cnt = NULL;
349 m->m_ext.ext_size = 0;
350 m->m_ext.ext_type = 0;
351 m->m_flags &= ~M_EXT;
352 uma_zfree(zone_mbuf, m);
356 * Attach the cluster from *m to *n, set up m_ext in *n
357 * and bump the refcount of the cluster.
360 mb_dupcl(struct mbuf *n, struct mbuf *m)
362 KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
363 KASSERT(m->m_ext.ref_cnt != NULL, ("%s: ref_cnt not set", __func__));
364 KASSERT((n->m_flags & M_EXT) == 0, ("%s: M_EXT set", __func__));
366 if (*(m->m_ext.ref_cnt) == 1)
367 *(m->m_ext.ref_cnt) += 1;
369 atomic_add_int(m->m_ext.ref_cnt, 1);
370 n->m_ext.ext_buf = m->m_ext.ext_buf;
371 n->m_ext.ext_free = m->m_ext.ext_free;
372 n->m_ext.ext_arg1 = m->m_ext.ext_arg1;
373 n->m_ext.ext_arg2 = m->m_ext.ext_arg2;
374 n->m_ext.ext_size = m->m_ext.ext_size;
375 n->m_ext.ref_cnt = m->m_ext.ref_cnt;
376 n->m_ext.ext_type = m->m_ext.ext_type;
378 n->m_flags |= m->m_flags & M_RDONLY;
382 * Clean up mbuf (chain) from any tags and packet headers.
383 * If "all" is set then the first mbuf in the chain will be
387 m_demote(struct mbuf *m0, int all)
391 for (m = all ? m0 : m0->m_next; m != NULL; m = m->m_next) {
392 if (m->m_flags & M_PKTHDR) {
393 m_tag_delete_chain(m, NULL);
394 m->m_flags &= ~M_PKTHDR;
395 bzero(&m->m_pkthdr, sizeof(struct pkthdr));
397 if (m != m0 && m->m_nextpkt != NULL) {
398 KASSERT(m->m_nextpkt == NULL,
399 ("%s: m_nextpkt not NULL", __func__));
400 m_freem(m->m_nextpkt);
403 m->m_flags = m->m_flags & (M_EXT|M_RDONLY|M_FREELIST|M_NOFREE);
408 * Sanity checks on mbuf (chain) for use in KASSERT() and general
410 * Returns 0 or panics when bad and 1 on all tests passed.
411 * Sanitize, 0 to run M_SANITY_ACTION, 1 to garble things so they
415 m_sanity(struct mbuf *m0, int sanitize)
422 #define M_SANITY_ACTION(s) panic("mbuf %p: " s, m)
424 #define M_SANITY_ACTION(s) printf("mbuf %p: " s, m)
427 for (m = m0; m != NULL; m = m->m_next) {
429 * Basic pointer checks. If any of these fails then some
430 * unrelated kernel memory before or after us is trashed.
431 * No way to recover from that.
433 a = ((m->m_flags & M_EXT) ? m->m_ext.ext_buf :
434 ((m->m_flags & M_PKTHDR) ? (caddr_t)(&m->m_pktdat) :
435 (caddr_t)(&m->m_dat)) );
436 b = (caddr_t)(a + (m->m_flags & M_EXT ? m->m_ext.ext_size :
437 ((m->m_flags & M_PKTHDR) ? MHLEN : MLEN)));
438 if ((caddr_t)m->m_data < a)
439 M_SANITY_ACTION("m_data outside mbuf data range left");
440 if ((caddr_t)m->m_data > b)
441 M_SANITY_ACTION("m_data outside mbuf data range right");
442 if ((caddr_t)m->m_data + m->m_len > b)
443 M_SANITY_ACTION("m_data + m_len exeeds mbuf space");
444 if ((m->m_flags & M_PKTHDR) && m->m_pkthdr.header) {
445 if ((caddr_t)m->m_pkthdr.header < a ||
446 (caddr_t)m->m_pkthdr.header > b)
447 M_SANITY_ACTION("m_pkthdr.header outside mbuf data range");
450 /* m->m_nextpkt may only be set on first mbuf in chain. */
451 if (m != m0 && m->m_nextpkt != NULL) {
453 m_freem(m->m_nextpkt);
454 m->m_nextpkt = (struct mbuf *)0xDEADC0DE;
456 M_SANITY_ACTION("m->m_nextpkt on in-chain mbuf");
459 /* packet length (not mbuf length!) calculation */
460 if (m0->m_flags & M_PKTHDR)
463 /* m_tags may only be attached to first mbuf in chain. */
464 if (m != m0 && m->m_flags & M_PKTHDR &&
465 !SLIST_EMPTY(&m->m_pkthdr.tags)) {
467 m_tag_delete_chain(m, NULL);
468 /* put in 0xDEADC0DE perhaps? */
470 M_SANITY_ACTION("m_tags on in-chain mbuf");
473 /* M_PKTHDR may only be set on first mbuf in chain */
474 if (m != m0 && m->m_flags & M_PKTHDR) {
476 bzero(&m->m_pkthdr, sizeof(m->m_pkthdr));
477 m->m_flags &= ~M_PKTHDR;
478 /* put in 0xDEADCODE and leave hdr flag in */
480 M_SANITY_ACTION("M_PKTHDR on in-chain mbuf");
484 if (pktlen && pktlen != m->m_pkthdr.len) {
488 M_SANITY_ACTION("m_pkthdr.len != mbuf chain length");
492 #undef M_SANITY_ACTION
497 * "Move" mbuf pkthdr from "from" to "to".
498 * "from" must have M_PKTHDR set, and "to" must be empty.
501 m_move_pkthdr(struct mbuf *to, struct mbuf *from)
505 /* see below for why these are not enabled */
507 /* Note: with MAC, this may not be a good assertion. */
508 KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags),
509 ("m_move_pkthdr: to has tags"));
513 * XXXMAC: It could be this should also occur for non-MAC?
515 if (to->m_flags & M_PKTHDR)
516 m_tag_delete_chain(to, NULL);
518 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
519 if ((to->m_flags & M_EXT) == 0)
520 to->m_data = to->m_pktdat;
521 to->m_pkthdr = from->m_pkthdr; /* especially tags */
522 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */
523 from->m_flags &= ~M_PKTHDR;
527 * Duplicate "from"'s mbuf pkthdr in "to".
528 * "from" must have M_PKTHDR set, and "to" must be empty.
529 * In particular, this does a deep copy of the packet tags.
532 m_dup_pkthdr(struct mbuf *to, struct mbuf *from, int how)
537 * The mbuf allocator only initializes the pkthdr
538 * when the mbuf is allocated with MGETHDR. Many users
539 * (e.g. m_copy*, m_prepend) use MGET and then
540 * smash the pkthdr as needed causing these
541 * assertions to trip. For now just disable them.
544 /* Note: with MAC, this may not be a good assertion. */
545 KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_dup_pkthdr: to has tags"));
547 MBUF_CHECKSLEEP(how);
549 if (to->m_flags & M_PKTHDR)
550 m_tag_delete_chain(to, NULL);
552 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
553 if ((to->m_flags & M_EXT) == 0)
554 to->m_data = to->m_pktdat;
555 to->m_pkthdr = from->m_pkthdr;
556 SLIST_INIT(&to->m_pkthdr.tags);
557 return (m_tag_copy_chain(to, from, MBTOM(how)));
561 * Lesser-used path for M_PREPEND:
562 * allocate new mbuf to prepend to chain,
566 m_prepend(struct mbuf *m, int len, int how)
570 if (m->m_flags & M_PKTHDR)
571 MGETHDR(mn, how, m->m_type);
573 MGET(mn, how, m->m_type);
578 if (m->m_flags & M_PKTHDR)
579 M_MOVE_PKTHDR(mn, m);
582 if(m->m_flags & M_PKTHDR) {
594 * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
595 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf.
596 * The wait parameter is a choice of M_WAITOK/M_NOWAIT from caller.
597 * Note that the copy is read-only, because clusters are not copied,
598 * only their reference counts are incremented.
601 m_copym(struct mbuf *m, int off0, int len, int wait)
603 struct mbuf *n, **np;
608 KASSERT(off >= 0, ("m_copym, negative off %d", off));
609 KASSERT(len >= 0, ("m_copym, negative len %d", len));
610 MBUF_CHECKSLEEP(wait);
611 if (off == 0 && m->m_flags & M_PKTHDR)
614 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain"));
624 KASSERT(len == M_COPYALL,
625 ("m_copym, length > size of mbuf chain"));
629 MGETHDR(n, wait, m->m_type);
631 MGET(n, wait, m->m_type);
636 if (!m_dup_pkthdr(n, m, wait))
638 if (len == M_COPYALL)
639 n->m_pkthdr.len -= off0;
641 n->m_pkthdr.len = len;
644 n->m_len = min(len, m->m_len - off);
645 if (m->m_flags & M_EXT) {
646 n->m_data = m->m_data + off;
649 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
651 if (len != M_COPYALL)
658 mbstat.m_mcfail++; /* XXX: No consistency. */
663 mbstat.m_mcfail++; /* XXX: No consistency. */
668 * Returns mbuf chain with new head for the prepending case.
669 * Copies from mbuf (chain) n from off for len to mbuf (chain) m
670 * either prepending or appending the data.
671 * The resulting mbuf (chain) m is fully writeable.
672 * m is destination (is made writeable)
673 * n is source, off is offset in source, len is len from offset
674 * dir, 0 append, 1 prepend
675 * how, wait or nowait
679 m_bcopyxxx(void *s, void *t, u_int len)
681 bcopy(s, t, (size_t)len);
686 m_copymdata(struct mbuf *m, struct mbuf *n, int off, int len,
689 struct mbuf *mm, *x, *z, *prev = NULL;
694 KASSERT(m != NULL && n != NULL, ("m_copymdata, no target or source"));
695 KASSERT(off >= 0, ("m_copymdata, negative off %d", off));
696 KASSERT(len >= 0, ("m_copymdata, negative len %d", len));
697 KASSERT(prep == 0 || prep == 1, ("m_copymdata, unknown direction %d", prep));
706 for (z = n; z != NULL; z = z->m_next)
708 if (len == M_COPYALL)
710 if (off + len > nlen || len < 1)
713 if (!M_WRITABLE(mm)) {
714 /* XXX: Use proper m_xxx function instead. */
715 x = m_getcl(how, MT_DATA, mm->m_flags);
718 bcopy(mm->m_ext.ext_buf, x->m_ext.ext_buf, x->m_ext.ext_size);
719 p = x->m_ext.ext_buf + (mm->m_data - mm->m_ext.ext_buf);
729 * Append/prepend the data. Allocating mbufs as necessary.
731 /* Shortcut if enough free space in first/last mbuf. */
732 if (!prep && M_TRAILINGSPACE(mm) >= len) {
733 m_apply(n, off, len, m_bcopyxxx, mtod(mm, caddr_t) +
736 mm->m_pkthdr.len += len;
739 if (prep && M_LEADINGSPACE(mm) >= len) {
740 mm->m_data = mtod(mm, caddr_t) - len;
741 m_apply(n, off, len, m_bcopyxxx, mtod(mm, caddr_t));
743 mm->m_pkthdr.len += len;
747 /* Expand first/last mbuf to cluster if possible. */
748 if (!prep && !(mm->m_flags & M_EXT) && len > M_TRAILINGSPACE(mm)) {
749 bcopy(mm->m_data, &buf, mm->m_len);
751 if (!(mm->m_flags & M_EXT))
753 bcopy(&buf, mm->m_ext.ext_buf, mm->m_len);
754 mm->m_data = mm->m_ext.ext_buf;
755 mm->m_pkthdr.header = NULL;
757 if (prep && !(mm->m_flags & M_EXT) && len > M_LEADINGSPACE(mm)) {
758 bcopy(mm->m_data, &buf, mm->m_len);
760 if (!(mm->m_flags & M_EXT))
762 bcopy(&buf, (caddr_t *)mm->m_ext.ext_buf +
763 mm->m_ext.ext_size - mm->m_len, mm->m_len);
764 mm->m_data = (caddr_t)mm->m_ext.ext_buf +
765 mm->m_ext.ext_size - mm->m_len;
766 mm->m_pkthdr.header = NULL;
769 /* Append/prepend as many mbuf (clusters) as necessary to fit len. */
770 if (!prep && len > M_TRAILINGSPACE(mm)) {
771 if (!m_getm(mm, len - M_TRAILINGSPACE(mm), how, MT_DATA))
774 if (prep && len > M_LEADINGSPACE(mm)) {
775 if (!(z = m_getm(NULL, len - M_LEADINGSPACE(mm), how, MT_DATA)))
778 for (x = z; x != NULL; x = x->m_next) {
779 i += x->m_flags & M_EXT ? x->m_ext.ext_size :
780 (x->m_flags & M_PKTHDR ? MHLEN : MLEN);
784 z->m_data += i - len;
785 m_move_pkthdr(mm, z);
790 /* Seek to start position in source mbuf. Optimization for long chains. */
798 /* Copy data into target mbuf. */
801 KASSERT(z != NULL, ("m_copymdata, falling off target edge"));
802 i = M_TRAILINGSPACE(z);
803 m_apply(n, off, i, m_bcopyxxx, mtod(z, caddr_t) + z->m_len);
805 /* fixup pkthdr.len if necessary */
806 if ((prep ? mm : m)->m_flags & M_PKTHDR)
807 (prep ? mm : m)->m_pkthdr.len += i;
812 return (prep ? mm : m);
816 * Copy an entire packet, including header (which must be present).
817 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
818 * Note that the copy is read-only, because clusters are not copied,
819 * only their reference counts are incremented.
820 * Preserve alignment of the first mbuf so if the creator has left
821 * some room at the beginning (e.g. for inserting protocol headers)
822 * the copies still have the room available.
825 m_copypacket(struct mbuf *m, int how)
827 struct mbuf *top, *n, *o;
829 MBUF_CHECKSLEEP(how);
830 MGET(n, how, m->m_type);
835 if (!m_dup_pkthdr(n, m, how))
838 if (m->m_flags & M_EXT) {
839 n->m_data = m->m_data;
842 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat );
843 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
848 MGET(o, how, m->m_type);
856 if (m->m_flags & M_EXT) {
857 n->m_data = m->m_data;
860 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
868 mbstat.m_mcfail++; /* XXX: No consistency. */
873 * Copy data from an mbuf chain starting "off" bytes from the beginning,
874 * continuing for "len" bytes, into the indicated buffer.
877 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp)
881 KASSERT(off >= 0, ("m_copydata, negative off %d", off));
882 KASSERT(len >= 0, ("m_copydata, negative len %d", len));
884 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain"));
891 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain"));
892 count = min(m->m_len - off, len);
893 bcopy(mtod(m, caddr_t) + off, cp, count);
902 * Copy a packet header mbuf chain into a completely new chain, including
903 * copying any mbuf clusters. Use this instead of m_copypacket() when
904 * you need a writable copy of an mbuf chain.
907 m_dup(struct mbuf *m, int how)
909 struct mbuf **p, *top = NULL;
910 int remain, moff, nsize;
912 MBUF_CHECKSLEEP(how);
918 /* While there's more data, get a new mbuf, tack it on, and fill it */
919 remain = m->m_pkthdr.len;
922 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */
925 /* Get the next new mbuf */
926 if (remain >= MINCLSIZE) {
927 n = m_getcl(how, m->m_type, 0);
930 n = m_get(how, m->m_type);
936 if (top == NULL) { /* First one, must be PKTHDR */
937 if (!m_dup_pkthdr(n, m, how)) {
941 if ((n->m_flags & M_EXT) == 0)
946 /* Link it into the new chain */
950 /* Copy data from original mbuf(s) into new mbuf */
951 while (n->m_len < nsize && m != NULL) {
952 int chunk = min(nsize - n->m_len, m->m_len - moff);
954 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk);
958 if (moff == m->m_len) {
964 /* Check correct total mbuf length */
965 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL),
966 ("%s: bogus m_pkthdr.len", __func__));
972 mbstat.m_mcfail++; /* XXX: No consistency. */
977 * Concatenate mbuf chain n to m.
978 * Both chains must be of the same type (e.g. MT_DATA).
979 * Any m_pkthdr is not updated.
982 m_cat(struct mbuf *m, struct mbuf *n)
987 if (!M_WRITABLE(m) ||
988 M_TRAILINGSPACE(m) < n->m_len) {
989 /* just join the two chains */
993 /* splat the data from one into the other */
994 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
996 m->m_len += n->m_len;
1002 m_adj(struct mbuf *mp, int req_len)
1008 if ((m = mp) == NULL)
1014 while (m != NULL && len > 0) {
1015 if (m->m_len <= len) {
1025 if (mp->m_flags & M_PKTHDR)
1026 mp->m_pkthdr.len -= (req_len - len);
1029 * Trim from tail. Scan the mbuf chain,
1030 * calculating its length and finding the last mbuf.
1031 * If the adjustment only affects this mbuf, then just
1032 * adjust and return. Otherwise, rescan and truncate
1033 * after the remaining size.
1039 if (m->m_next == (struct mbuf *)0)
1043 if (m->m_len >= len) {
1045 if (mp->m_flags & M_PKTHDR)
1046 mp->m_pkthdr.len -= len;
1053 * Correct length for chain is "count".
1054 * Find the mbuf with last data, adjust its length,
1055 * and toss data from remaining mbufs on chain.
1058 if (m->m_flags & M_PKTHDR)
1059 m->m_pkthdr.len = count;
1060 for (; m; m = m->m_next) {
1061 if (m->m_len >= count) {
1063 if (m->m_next != NULL) {
1075 * Rearange an mbuf chain so that len bytes are contiguous
1076 * and in the data area of an mbuf (so that mtod will work
1077 * for a structure of size len). Returns the resulting
1078 * mbuf chain on success, frees it and returns null on failure.
1079 * If there is room, it will add up to max_protohdr-len extra bytes to the
1080 * contiguous region in an attempt to avoid being called next time.
1083 m_pullup(struct mbuf *n, int len)
1090 * If first mbuf has no cluster, and has room for len bytes
1091 * without shifting current data, pullup into it,
1092 * otherwise allocate a new mbuf to prepend to the chain.
1094 if ((n->m_flags & M_EXT) == 0 &&
1095 n->m_data + len < &n->m_dat[MLEN] && n->m_next) {
1096 if (n->m_len >= len)
1104 MGET(m, M_NOWAIT, n->m_type);
1108 if (n->m_flags & M_PKTHDR)
1109 M_MOVE_PKTHDR(m, n);
1111 space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
1113 count = min(min(max(len, max_protohdr), space), n->m_len);
1114 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1124 } while (len > 0 && n);
1133 mbstat.m_mpfail++; /* XXX: No consistency. */
1138 * Like m_pullup(), except a new mbuf is always allocated, and we allow
1139 * the amount of empty space before the data in the new mbuf to be specified
1140 * (in the event that the caller expects to prepend later).
1145 m_copyup(struct mbuf *n, int len, int dstoff)
1150 if (len > (MHLEN - dstoff))
1152 MGET(m, M_NOWAIT, n->m_type);
1156 if (n->m_flags & M_PKTHDR)
1157 M_MOVE_PKTHDR(m, n);
1158 m->m_data += dstoff;
1159 space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
1161 count = min(min(max(len, max_protohdr), space), n->m_len);
1162 memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t),
1172 } while (len > 0 && n);
1186 * Partition an mbuf chain in two pieces, returning the tail --
1187 * all but the first len0 bytes. In case of failure, it returns NULL and
1188 * attempts to restore the chain to its original state.
1190 * Note that the resulting mbufs might be read-only, because the new
1191 * mbuf can end up sharing an mbuf cluster with the original mbuf if
1192 * the "breaking point" happens to lie within a cluster mbuf. Use the
1193 * M_WRITABLE() macro to check for this case.
1196 m_split(struct mbuf *m0, int len0, int wait)
1199 u_int len = len0, remain;
1201 MBUF_CHECKSLEEP(wait);
1202 for (m = m0; m && len > m->m_len; m = m->m_next)
1206 remain = m->m_len - len;
1207 if (m0->m_flags & M_PKTHDR) {
1208 MGETHDR(n, wait, m0->m_type);
1211 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
1212 n->m_pkthdr.len = m0->m_pkthdr.len - len0;
1213 m0->m_pkthdr.len = len0;
1214 if (m->m_flags & M_EXT)
1216 if (remain > MHLEN) {
1217 /* m can't be the lead packet */
1219 n->m_next = m_split(m, len, wait);
1220 if (n->m_next == NULL) {
1228 MH_ALIGN(n, remain);
1229 } else if (remain == 0) {
1234 MGET(n, wait, m->m_type);
1240 if (m->m_flags & M_EXT) {
1241 n->m_data = m->m_data + len;
1244 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain);
1248 n->m_next = m->m_next;
1253 * Routine to copy from device local memory into mbufs.
1254 * Note that `off' argument is offset into first mbuf of target chain from
1255 * which to begin copying the data to.
1258 m_devget(char *buf, int totlen, int off, struct ifnet *ifp,
1259 void (*copy)(char *from, caddr_t to, u_int len))
1262 struct mbuf *top = NULL, **mp = ⊤
1265 if (off < 0 || off > MHLEN)
1268 while (totlen > 0) {
1269 if (top == NULL) { /* First one, must be PKTHDR */
1270 if (totlen + off >= MINCLSIZE) {
1271 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
1274 m = m_gethdr(M_NOWAIT, MT_DATA);
1277 /* Place initial small packet/header at end of mbuf */
1278 if (m && totlen + off + max_linkhdr <= MLEN) {
1279 m->m_data += max_linkhdr;
1285 m->m_pkthdr.rcvif = ifp;
1286 m->m_pkthdr.len = totlen;
1288 if (totlen + off >= MINCLSIZE) {
1289 m = m_getcl(M_NOWAIT, MT_DATA, 0);
1292 m = m_get(M_NOWAIT, MT_DATA);
1305 m->m_len = len = min(totlen, len);
1307 copy(buf, mtod(m, caddr_t), (u_int)len);
1309 bcopy(buf, mtod(m, caddr_t), (u_int)len);
1319 * Copy data from a buffer back into the indicated mbuf chain,
1320 * starting "off" bytes from the beginning, extending the mbuf
1321 * chain if necessary.
1324 m_copyback(struct mbuf *m0, int off, int len, c_caddr_t cp)
1327 struct mbuf *m = m0, *n;
1332 while (off > (mlen = m->m_len)) {
1335 if (m->m_next == NULL) {
1336 n = m_get(M_NOWAIT, m->m_type);
1339 bzero(mtod(n, caddr_t), MLEN);
1340 n->m_len = min(MLEN, len + off);
1346 if (m->m_next == NULL && (len > m->m_len - off)) {
1347 m->m_len += min(len - (m->m_len - off),
1348 M_TRAILINGSPACE(m));
1350 mlen = min (m->m_len - off, len);
1351 bcopy(cp, off + mtod(m, caddr_t), (u_int)mlen);
1359 if (m->m_next == NULL) {
1360 n = m_get(M_NOWAIT, m->m_type);
1363 n->m_len = min(MLEN, len);
1368 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
1369 m->m_pkthdr.len = totlen;
1373 * Append the specified data to the indicated mbuf chain,
1374 * Extend the mbuf chain if the new data does not fit in
1377 * Return 1 if able to complete the job; otherwise 0.
1380 m_append(struct mbuf *m0, int len, c_caddr_t cp)
1383 int remainder, space;
1385 for (m = m0; m->m_next != NULL; m = m->m_next)
1388 space = M_TRAILINGSPACE(m);
1391 * Copy into available space.
1393 if (space > remainder)
1395 bcopy(cp, mtod(m, caddr_t) + m->m_len, space);
1397 cp += space, remainder -= space;
1399 while (remainder > 0) {
1401 * Allocate a new mbuf; could check space
1402 * and allocate a cluster instead.
1404 n = m_get(M_NOWAIT, m->m_type);
1407 n->m_len = min(MLEN, remainder);
1408 bcopy(cp, mtod(n, caddr_t), n->m_len);
1409 cp += n->m_len, remainder -= n->m_len;
1413 if (m0->m_flags & M_PKTHDR)
1414 m0->m_pkthdr.len += len - remainder;
1415 return (remainder == 0);
1419 * Apply function f to the data in an mbuf chain starting "off" bytes from
1420 * the beginning, continuing for "len" bytes.
1423 m_apply(struct mbuf *m, int off, int len,
1424 int (*f)(void *, void *, u_int), void *arg)
1429 KASSERT(off >= 0, ("m_apply, negative off %d", off));
1430 KASSERT(len >= 0, ("m_apply, negative len %d", len));
1432 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
1439 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
1440 count = min(m->m_len - off, len);
1441 rval = (*f)(arg, mtod(m, caddr_t) + off, count);
1452 * Return a pointer to mbuf/offset of location in mbuf chain.
1455 m_getptr(struct mbuf *m, int loc, int *off)
1459 /* Normal end of search. */
1460 if (m->m_len > loc) {
1465 if (m->m_next == NULL) {
1467 /* Point at the end of valid data. */
1480 m_print(const struct mbuf *m, int maxlen)
1484 const struct mbuf *m2;
1487 printf("mbuf: %p\n", m);
1491 if (m->m_flags & M_PKTHDR)
1492 len = m->m_pkthdr.len;
1496 while (m2 != NULL && (len == -1 || len)) {
1498 if (maxlen != -1 && pdata > maxlen)
1500 printf("mbuf: %p len: %d, next: %p, %b%s", m2, m2->m_len,
1501 m2->m_next, m2->m_flags, "\20\20freelist\17skipfw"
1502 "\11proto5\10proto4\7proto3\6proto2\5proto1\4rdonly"
1503 "\3eor\2pkthdr\1ext", pdata ? "" : "\n");
1505 printf(", %*D\n", pdata, (u_char *)m2->m_data, "-");
1511 printf("%d bytes unaccounted for.\n", len);
1516 m_fixhdr(struct mbuf *m0)
1520 len = m_length(m0, NULL);
1521 m0->m_pkthdr.len = len;
1526 m_length(struct mbuf *m0, struct mbuf **last)
1532 for (m = m0; m != NULL; m = m->m_next) {
1534 if (m->m_next == NULL)
1543 * Defragment a mbuf chain, returning the shortest possible
1544 * chain of mbufs and clusters. If allocation fails and
1545 * this cannot be completed, NULL will be returned, but
1546 * the passed in chain will be unchanged. Upon success,
1547 * the original chain will be freed, and the new chain
1550 * If a non-packet header is passed in, the original
1551 * mbuf (chain?) will be returned unharmed.
1554 m_defrag(struct mbuf *m0, int how)
1556 struct mbuf *m_new = NULL, *m_final = NULL;
1557 int progress = 0, length;
1559 MBUF_CHECKSLEEP(how);
1560 if (!(m0->m_flags & M_PKTHDR))
1563 m_fixhdr(m0); /* Needed sanity check */
1565 #ifdef MBUF_STRESS_TEST
1566 if (m_defragrandomfailures) {
1567 int temp = arc4random() & 0xff;
1573 if (m0->m_pkthdr.len > MHLEN)
1574 m_final = m_getcl(how, MT_DATA, M_PKTHDR);
1576 m_final = m_gethdr(how, MT_DATA);
1578 if (m_final == NULL)
1581 if (m_dup_pkthdr(m_final, m0, how) == 0)
1586 while (progress < m0->m_pkthdr.len) {
1587 length = m0->m_pkthdr.len - progress;
1588 if (length > MCLBYTES)
1591 if (m_new == NULL) {
1593 m_new = m_getcl(how, MT_DATA, 0);
1595 m_new = m_get(how, MT_DATA);
1600 m_copydata(m0, progress, length, mtod(m_new, caddr_t));
1602 m_new->m_len = length;
1603 if (m_new != m_final)
1604 m_cat(m_final, m_new);
1607 #ifdef MBUF_STRESS_TEST
1608 if (m0->m_next == NULL)
1613 #ifdef MBUF_STRESS_TEST
1615 m_defragbytes += m0->m_pkthdr.len;
1619 #ifdef MBUF_STRESS_TEST
1628 * Defragment an mbuf chain, returning at most maxfrags separate
1629 * mbufs+clusters. If this is not possible NULL is returned and
1630 * the original mbuf chain is left in it's present (potentially
1631 * modified) state. We use two techniques: collapsing consecutive
1632 * mbufs and replacing consecutive mbufs by a cluster.
1634 * NB: this should really be named m_defrag but that name is taken
1637 m_collapse(struct mbuf *m0, int how, int maxfrags)
1639 struct mbuf *m, *n, *n2, **prev;
1643 * Calculate the current number of frags.
1646 for (m = m0; m != NULL; m = m->m_next)
1649 * First, try to collapse mbufs. Note that we always collapse
1650 * towards the front so we don't need to deal with moving the
1651 * pkthdr. This may be suboptimal if the first mbuf has much
1652 * less data than the following.
1660 if (M_WRITABLE(m) &&
1661 n->m_len < M_TRAILINGSPACE(m)) {
1662 bcopy(mtod(n, void *), mtod(m, char *) + m->m_len,
1664 m->m_len += n->m_len;
1665 m->m_next = n->m_next;
1667 if (--curfrags <= maxfrags)
1672 KASSERT(maxfrags > 1,
1673 ("maxfrags %u, but normal collapse failed", maxfrags));
1675 * Collapse consecutive mbufs to a cluster.
1677 prev = &m0->m_next; /* NB: not the first mbuf */
1678 while ((n = *prev) != NULL) {
1679 if ((n2 = n->m_next) != NULL &&
1680 n->m_len + n2->m_len < MCLBYTES) {
1681 m = m_getcl(how, MT_DATA, 0);
1684 bcopy(mtod(n, void *), mtod(m, void *), n->m_len);
1685 bcopy(mtod(n2, void *), mtod(m, char *) + n->m_len,
1687 m->m_len = n->m_len + n2->m_len;
1688 m->m_next = n2->m_next;
1692 if (--curfrags <= maxfrags) /* +1 cl -2 mbufs */
1695 * Still not there, try the normal collapse
1696 * again before we allocate another cluster.
1703 * No place where we can collapse to a cluster; punt.
1704 * This can occur if, for example, you request 2 frags
1705 * but the packet requires that both be clusters (we
1706 * never reallocate the first mbuf to avoid moving the
1713 #ifdef MBUF_STRESS_TEST
1716 * Fragment an mbuf chain. There's no reason you'd ever want to do
1717 * this in normal usage, but it's great for stress testing various
1720 * If fragmentation is not possible, the original chain will be
1723 * Possible length values:
1724 * 0 no fragmentation will occur
1725 * > 0 each fragment will be of the specified length
1726 * -1 each fragment will be the same random value in length
1727 * -2 each fragment's length will be entirely random
1728 * (Random values range from 1 to 256)
1731 m_fragment(struct mbuf *m0, int how, int length)
1733 struct mbuf *m_new = NULL, *m_final = NULL;
1736 if (!(m0->m_flags & M_PKTHDR))
1739 if ((length == 0) || (length < -2))
1742 m_fixhdr(m0); /* Needed sanity check */
1744 m_final = m_getcl(how, MT_DATA, M_PKTHDR);
1746 if (m_final == NULL)
1749 if (m_dup_pkthdr(m_final, m0, how) == 0)
1755 length = 1 + (arc4random() & 255);
1757 while (progress < m0->m_pkthdr.len) {
1763 fraglen = 1 + (arc4random() & 255);
1764 if (fraglen > m0->m_pkthdr.len - progress)
1765 fraglen = m0->m_pkthdr.len - progress;
1767 if (fraglen > MCLBYTES)
1770 if (m_new == NULL) {
1771 m_new = m_getcl(how, MT_DATA, 0);
1776 m_copydata(m0, progress, fraglen, mtod(m_new, caddr_t));
1777 progress += fraglen;
1778 m_new->m_len = fraglen;
1779 if (m_new != m_final)
1780 m_cat(m_final, m_new);
1789 /* Return the original chain on failure */
1796 * Copy the contents of uio into a properly sized mbuf chain.
1799 m_uiotombuf(struct uio *uio, int how, int len, int align, int flags)
1801 struct mbuf *m, *mb;
1807 * len can be zero or an arbitrary large value bound by
1808 * the total data supplied by the uio.
1811 total = min(uio->uio_resid, len);
1813 total = uio->uio_resid;
1816 * The smallest unit returned by m_getm2() is a single mbuf
1817 * with pkthdr. We can't align past it.
1823 * Give us the full allocation or nothing.
1824 * If len is zero return the smallest empty mbuf.
1826 m = m_getm2(NULL, max(total + align, 1), how, MT_DATA, flags);
1831 /* Fill all mbufs with uio data and update header information. */
1832 for (mb = m; mb != NULL; mb = mb->m_next) {
1833 length = min(M_TRAILINGSPACE(mb), total - progress);
1835 error = uiomove(mtod(mb, void *), length, uio);
1843 if (flags & M_PKTHDR)
1844 m->m_pkthdr.len += length;
1846 KASSERT(progress == total, ("%s: progress != total", __func__));
1852 * Copy an mbuf chain into a uio limited by len if set.
1855 m_mbuftouio(struct uio *uio, struct mbuf *m, int len)
1857 int error, length, total;
1861 total = min(uio->uio_resid, len);
1863 total = uio->uio_resid;
1865 /* Fill the uio with data from the mbufs. */
1866 for (; m != NULL; m = m->m_next) {
1867 length = min(m->m_len, total - progress);
1869 error = uiomove(mtod(m, void *), length, uio);
1880 * Set the m_data pointer of a newly-allocated mbuf
1881 * to place an object of the specified size at the
1882 * end of the mbuf, longword aligned.
1885 m_align(struct mbuf *m, int len)
1889 if (m->m_flags & M_EXT)
1890 adjust = m->m_ext.ext_size - len;
1891 else if (m->m_flags & M_PKTHDR)
1892 adjust = MHLEN - len;
1894 adjust = MLEN - len;
1895 m->m_data += adjust &~ (sizeof(long)-1);
1899 * Create a writable copy of the mbuf chain. While doing this
1900 * we compact the chain with a goal of producing a chain with
1901 * at most two mbufs. The second mbuf in this chain is likely
1902 * to be a cluster. The primary purpose of this work is to create
1903 * a writable packet for encryption, compression, etc. The
1904 * secondary goal is to linearize the data so the data can be
1905 * passed to crypto hardware in the most efficient manner possible.
1908 m_unshare(struct mbuf *m0, int how)
1910 struct mbuf *m, *mprev;
1911 struct mbuf *n, *mfirst, *mlast;
1915 for (m = m0; m != NULL; m = mprev->m_next) {
1917 * Regular mbufs are ignored unless there's a cluster
1918 * in front of it that we can use to coalesce. We do
1919 * the latter mainly so later clusters can be coalesced
1920 * also w/o having to handle them specially (i.e. convert
1921 * mbuf+cluster -> cluster). This optimization is heavily
1922 * influenced by the assumption that we're running over
1923 * Ethernet where MCLBYTES is large enough that the max
1924 * packet size will permit lots of coalescing into a
1925 * single cluster. This in turn permits efficient
1926 * crypto operations, especially when using hardware.
1928 if ((m->m_flags & M_EXT) == 0) {
1929 if (mprev && (mprev->m_flags & M_EXT) &&
1930 m->m_len <= M_TRAILINGSPACE(mprev)) {
1931 /* XXX: this ignores mbuf types */
1932 memcpy(mtod(mprev, caddr_t) + mprev->m_len,
1933 mtod(m, caddr_t), m->m_len);
1934 mprev->m_len += m->m_len;
1935 mprev->m_next = m->m_next; /* unlink from chain */
1936 m_free(m); /* reclaim mbuf */
1938 newipsecstat.ips_mbcoalesced++;
1946 * Writable mbufs are left alone (for now).
1948 if (M_WRITABLE(m)) {
1954 * Not writable, replace with a copy or coalesce with
1955 * the previous mbuf if possible (since we have to copy
1956 * it anyway, we try to reduce the number of mbufs and
1957 * clusters so that future work is easier).
1959 KASSERT(m->m_flags & M_EXT, ("m_flags 0x%x", m->m_flags));
1960 /* NB: we only coalesce into a cluster or larger */
1961 if (mprev != NULL && (mprev->m_flags & M_EXT) &&
1962 m->m_len <= M_TRAILINGSPACE(mprev)) {
1963 /* XXX: this ignores mbuf types */
1964 memcpy(mtod(mprev, caddr_t) + mprev->m_len,
1965 mtod(m, caddr_t), m->m_len);
1966 mprev->m_len += m->m_len;
1967 mprev->m_next = m->m_next; /* unlink from chain */
1968 m_free(m); /* reclaim mbuf */
1970 newipsecstat.ips_clcoalesced++;
1976 * Allocate new space to hold the copy...
1978 /* XXX why can M_PKTHDR be set past the first mbuf? */
1979 if (mprev == NULL && (m->m_flags & M_PKTHDR)) {
1981 * NB: if a packet header is present we must
1982 * allocate the mbuf separately from any cluster
1983 * because M_MOVE_PKTHDR will smash the data
1984 * pointer and drop the M_EXT marker.
1986 MGETHDR(n, how, m->m_type);
1991 M_MOVE_PKTHDR(n, m);
1993 if ((n->m_flags & M_EXT) == 0) {
1999 n = m_getcl(how, m->m_type, m->m_flags);
2006 * ... and copy the data. We deal with jumbo mbufs
2007 * (i.e. m_len > MCLBYTES) by splitting them into
2008 * clusters. We could just malloc a buffer and make
2009 * it external but too many device drivers don't know
2010 * how to break up the non-contiguous memory when
2018 int cc = min(len, MCLBYTES);
2019 memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, cc);
2025 newipsecstat.ips_clcopied++;
2033 n = m_getcl(how, m->m_type, m->m_flags);
2040 n->m_next = m->m_next;
2042 m0 = mfirst; /* new head of chain */
2044 mprev->m_next = mfirst; /* replace old mbuf */
2045 m_free(m); /* release old mbuf */
2051 #ifdef MBUF_PROFILING
2053 #define MP_BUCKETS 32 /* don't just change this as things may overflow.*/
2054 struct mbufprofile {
2055 uintmax_t wasted[MP_BUCKETS];
2056 uintmax_t used[MP_BUCKETS];
2057 uintmax_t segments[MP_BUCKETS];
2060 #define MP_MAXDIGITS 21 /* strlen("16,000,000,000,000,000,000") == 21 */
2061 #define MP_NUMLINES 6
2062 #define MP_NUMSPERLINE 16
2063 #define MP_EXTRABYTES 64 /* > strlen("used:\nwasted:\nsegments:\n") */
2064 /* work out max space needed and add a bit of spare space too */
2065 #define MP_MAXLINE ((MP_MAXDIGITS+1) * MP_NUMSPERLINE)
2066 #define MP_BUFSIZE ((MP_MAXLINE * MP_NUMLINES) + 1 + MP_EXTRABYTES)
2068 char mbprofbuf[MP_BUFSIZE];
2071 m_profile(struct mbuf *m)
2080 if (m->m_flags & M_EXT) {
2081 wasted += MHLEN - sizeof(m->m_ext) +
2082 m->m_ext.ext_size - m->m_len;
2084 if (m->m_flags & M_PKTHDR)
2085 wasted += MHLEN - m->m_len;
2087 wasted += MLEN - m->m_len;
2091 /* be paranoid.. it helps */
2092 if (segments > MP_BUCKETS - 1)
2093 segments = MP_BUCKETS - 1;
2096 if (wasted > 100000)
2098 /* store in the appropriate bucket */
2099 /* don't bother locking. if it's slightly off, so what? */
2100 mbprof.segments[segments]++;
2101 mbprof.used[fls(used)]++;
2102 mbprof.wasted[fls(wasted)]++;
2106 mbprof_textify(void)
2113 p = &mbprof.wasted[0];
2115 offset = snprintf(c, MP_MAXLINE + 10,
2117 "%ju %ju %ju %ju %ju %ju %ju %ju "
2118 "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2119 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2120 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2122 p = &mbprof.wasted[16];
2124 offset = snprintf(c, MP_MAXLINE,
2125 "%ju %ju %ju %ju %ju %ju %ju %ju "
2126 "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2127 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2128 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2130 p = &mbprof.used[0];
2132 offset = snprintf(c, MP_MAXLINE + 10,
2134 "%ju %ju %ju %ju %ju %ju %ju %ju "
2135 "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2136 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2137 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2139 p = &mbprof.used[16];
2141 offset = snprintf(c, MP_MAXLINE,
2142 "%ju %ju %ju %ju %ju %ju %ju %ju "
2143 "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2144 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2145 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2147 p = &mbprof.segments[0];
2149 offset = snprintf(c, MP_MAXLINE + 10,
2151 "%ju %ju %ju %ju %ju %ju %ju %ju "
2152 "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2153 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2154 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2156 p = &mbprof.segments[16];
2158 offset = snprintf(c, MP_MAXLINE,
2159 "%ju %ju %ju %ju %ju %ju %ju %ju "
2160 "%ju %ju %ju %ju %ju %ju %ju %jju",
2161 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2162 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2167 mbprof_handler(SYSCTL_HANDLER_ARGS)
2172 error = SYSCTL_OUT(req, mbprofbuf, strlen(mbprofbuf) + 1);
2177 mbprof_clr_handler(SYSCTL_HANDLER_ARGS)
2182 error = sysctl_handle_int(oidp, &clear, 0, req);
2183 if (error || !req->newptr)
2187 bzero(&mbprof, sizeof(mbprof));
2194 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofile, CTLTYPE_STRING|CTLFLAG_RD,
2195 NULL, 0, mbprof_handler, "A", "mbuf profiling statistics");
2197 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofileclr, CTLTYPE_INT|CTLFLAG_RW,
2198 NULL, 0, mbprof_clr_handler, "I", "clear mbuf profiling statistics");