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 * Ensure the correct size of various mbuf parameters. It could be off due
89 * to compiler-induced padding and alignment artifacts.
91 CTASSERT(sizeof(struct mbuf) == MSIZE);
92 CTASSERT(MSIZE - offsetof(struct mbuf, m_dat) == MLEN);
93 CTASSERT(MSIZE - offsetof(struct mbuf, m_pktdat) == MHLEN);
96 * m_get2() allocates minimum mbuf that would fit "size" argument.
99 m_get2(int size, int how, short type, int flags)
107 if (size <= MHLEN || (size <= MLEN && (flags & M_PKTHDR) == 0))
108 return (uma_zalloc_arg(zone_mbuf, &args, how));
109 if (size <= MCLBYTES)
110 return (uma_zalloc_arg(zone_pack, &args, how));
112 if (size > MJUMPAGESIZE)
115 m = uma_zalloc_arg(zone_mbuf, &args, how);
119 n = uma_zalloc_arg(zone_jumbop, m, how);
121 uma_zfree(zone_mbuf, m);
129 * m_getjcl() returns an mbuf with a cluster of the specified size attached.
130 * For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
133 m_getjcl(int how, short type, int flags, int size)
139 if (size == MCLBYTES)
140 return m_getcl(how, type, flags);
145 m = uma_zalloc_arg(zone_mbuf, &args, how);
149 zone = m_getzone(size);
150 n = uma_zalloc_arg(zone, m, how);
152 uma_zfree(zone_mbuf, m);
159 * Allocate a given length worth of mbufs and/or clusters (whatever fits
160 * best) and return a pointer to the top of the allocated chain. If an
161 * existing mbuf chain is provided, then we will append the new chain
162 * to the existing one but still return the top of the newly allocated
166 m_getm2(struct mbuf *m, int len, int how, short type, int flags)
168 struct mbuf *mb, *nm = NULL, *mtail = NULL;
170 KASSERT(len >= 0, ("%s: len is < 0", __func__));
172 /* Validate flags. */
173 flags &= (M_PKTHDR | M_EOR);
175 /* Packet header mbuf must be first in chain. */
176 if ((flags & M_PKTHDR) && m != NULL)
179 /* Loop and append maximum sized mbufs to the chain tail. */
182 mb = m_getjcl(how, type, (flags & M_PKTHDR),
184 else if (len >= MINCLSIZE)
185 mb = m_getcl(how, type, (flags & M_PKTHDR));
186 else if (flags & M_PKTHDR)
187 mb = m_gethdr(how, type);
189 mb = m_get(how, type);
191 /* Fail the whole operation if one mbuf can't be allocated. */
199 len -= (mb->m_flags & M_EXT) ? mb->m_ext.ext_size :
200 ((mb->m_flags & M_PKTHDR) ? MHLEN : MLEN);
206 flags &= ~M_PKTHDR; /* Only valid on the first mbuf. */
209 mtail->m_flags |= M_EOR; /* Only valid on the last mbuf. */
211 /* If mbuf was supplied, append new chain to the end of it. */
213 for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next)
216 mtail->m_flags &= ~M_EOR;
224 * Free an entire chain of mbufs and associated external buffers, if
228 m_freem(struct mbuf *mb)
236 * Configure a provided mbuf to refer to the provided external storage
237 * buffer and setup a reference count for said buffer. If the setting
238 * up of the reference count fails, the M_EXT bit will not be set. If
239 * successfull, the M_EXT bit is set in the mbuf's flags.
242 * mb The existing mbuf to which to attach the provided buffer.
243 * buf The address of the provided external storage buffer.
244 * size The size of the provided buffer.
245 * freef A pointer to a routine that is responsible for freeing the
246 * provided external storage buffer.
247 * args A pointer to an argument structure (of any type) to be passed
248 * to the provided freef routine (may be NULL).
249 * flags Any other flags to be passed to the provided mbuf.
250 * type The type that the external storage buffer should be
257 m_extadd(struct mbuf *mb, caddr_t buf, u_int size,
258 void (*freef)(struct mbuf *, void *, void *), void *arg1, void *arg2,
259 int flags, int type, int wait)
261 KASSERT(type != EXT_CLUSTER, ("%s: EXT_CLUSTER not allowed", __func__));
263 if (type != EXT_EXTREF)
264 mb->m_ext.ext_cnt = uma_zalloc(zone_ext_refcnt, wait);
266 if (mb->m_ext.ext_cnt == NULL)
269 *(mb->m_ext.ext_cnt) = 1;
270 mb->m_flags |= (M_EXT | flags);
271 mb->m_ext.ext_buf = buf;
272 mb->m_data = mb->m_ext.ext_buf;
273 mb->m_ext.ext_size = size;
274 mb->m_ext.ext_free = freef;
275 mb->m_ext.ext_arg1 = arg1;
276 mb->m_ext.ext_arg2 = arg2;
277 mb->m_ext.ext_type = type;
278 mb->m_ext.ext_flags = 0;
284 * Non-directly-exported function to clean up after mbufs with M_EXT
285 * storage attached to them if the reference count hits 1.
288 mb_free_ext(struct mbuf *m)
292 KASSERT(m->m_flags & M_EXT, ("%s: M_EXT not set on %p", __func__, m));
295 * Check if the header is embedded in the cluster.
297 freembuf = (m->m_flags & M_NOFREE) ? 0 : 1;
299 switch (m->m_ext.ext_type) {
301 sf_ext_free(m->m_ext.ext_arg1, m->m_ext.ext_arg2);
304 KASSERT(m->m_ext.ext_cnt != NULL,
305 ("%s: no refcounting pointer on %p", __func__, m));
307 * Free attached storage if this mbuf is the only
310 if (*(m->m_ext.ext_cnt) != 1) {
311 if (atomic_fetchadd_int(m->m_ext.ext_cnt, -1) != 1)
315 switch (m->m_ext.ext_type) {
316 case EXT_PACKET: /* The packet zone is special. */
317 if (*(m->m_ext.ext_cnt) == 0)
318 *(m->m_ext.ext_cnt) = 1;
319 uma_zfree(zone_pack, m);
320 return; /* Job done. */
322 uma_zfree(zone_clust, m->m_ext.ext_buf);
325 uma_zfree(zone_jumbop, m->m_ext.ext_buf);
328 uma_zfree(zone_jumbo9, m->m_ext.ext_buf);
331 uma_zfree(zone_jumbo16, m->m_ext.ext_buf);
336 *(m->m_ext.ext_cnt) = 0;
337 uma_zfree(zone_ext_refcnt, __DEVOLATILE(u_int *,
341 KASSERT(m->m_ext.ext_free != NULL,
342 ("%s: ext_free not set", __func__));
343 (*(m->m_ext.ext_free))(m, m->m_ext.ext_arg1,
347 KASSERT(m->m_ext.ext_type == 0,
348 ("%s: unknown ext_type", __func__));
353 uma_zfree(zone_mbuf, m);
357 * Attach the cluster from *m to *n, set up m_ext in *n
358 * and bump the refcount of the cluster.
361 mb_dupcl(struct mbuf *n, struct mbuf *m)
364 KASSERT(m->m_flags & M_EXT, ("%s: M_EXT not set on %p", __func__, m));
365 KASSERT(!(n->m_flags & M_EXT), ("%s: M_EXT set on %p", __func__, n));
367 switch (m->m_ext.ext_type) {
369 sf_ext_ref(m->m_ext.ext_arg1, m->m_ext.ext_arg2);
372 KASSERT(m->m_ext.ext_cnt != NULL,
373 ("%s: no refcounting pointer on %p", __func__, m));
374 if (*(m->m_ext.ext_cnt) == 1)
375 *(m->m_ext.ext_cnt) += 1;
377 atomic_add_int(m->m_ext.ext_cnt, 1);
382 n->m_flags |= m->m_flags & M_RDONLY;
386 * Clean up mbuf (chain) from any tags and packet headers.
387 * If "all" is set then the first mbuf in the chain will be
391 m_demote(struct mbuf *m0, int all, int flags)
395 for (m = all ? m0 : m0->m_next; m != NULL; m = m->m_next) {
396 KASSERT(m->m_nextpkt == NULL, ("%s: m_nextpkt in m %p, m0 %p",
398 if (m->m_flags & M_PKTHDR) {
399 m_tag_delete_chain(m, NULL);
400 m->m_flags &= ~M_PKTHDR;
401 bzero(&m->m_pkthdr, sizeof(struct pkthdr));
403 m->m_flags = m->m_flags & (M_EXT | M_RDONLY | M_NOFREE | flags);
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");
445 /* m->m_nextpkt may only be set on first mbuf in chain. */
446 if (m != m0 && m->m_nextpkt != NULL) {
448 m_freem(m->m_nextpkt);
449 m->m_nextpkt = (struct mbuf *)0xDEADC0DE;
451 M_SANITY_ACTION("m->m_nextpkt on in-chain mbuf");
454 /* packet length (not mbuf length!) calculation */
455 if (m0->m_flags & M_PKTHDR)
458 /* m_tags may only be attached to first mbuf in chain. */
459 if (m != m0 && m->m_flags & M_PKTHDR &&
460 !SLIST_EMPTY(&m->m_pkthdr.tags)) {
462 m_tag_delete_chain(m, NULL);
463 /* put in 0xDEADC0DE perhaps? */
465 M_SANITY_ACTION("m_tags on in-chain mbuf");
468 /* M_PKTHDR may only be set on first mbuf in chain */
469 if (m != m0 && m->m_flags & M_PKTHDR) {
471 bzero(&m->m_pkthdr, sizeof(m->m_pkthdr));
472 m->m_flags &= ~M_PKTHDR;
473 /* put in 0xDEADCODE and leave hdr flag in */
475 M_SANITY_ACTION("M_PKTHDR on in-chain mbuf");
479 if (pktlen && pktlen != m->m_pkthdr.len) {
483 M_SANITY_ACTION("m_pkthdr.len != mbuf chain length");
487 #undef M_SANITY_ACTION
492 * "Move" mbuf pkthdr from "from" to "to".
493 * "from" must have M_PKTHDR set, and "to" must be empty.
496 m_move_pkthdr(struct mbuf *to, struct mbuf *from)
500 /* see below for why these are not enabled */
502 /* Note: with MAC, this may not be a good assertion. */
503 KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags),
504 ("m_move_pkthdr: to has tags"));
508 * XXXMAC: It could be this should also occur for non-MAC?
510 if (to->m_flags & M_PKTHDR)
511 m_tag_delete_chain(to, NULL);
513 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
514 if ((to->m_flags & M_EXT) == 0)
515 to->m_data = to->m_pktdat;
516 to->m_pkthdr = from->m_pkthdr; /* especially tags */
517 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */
518 from->m_flags &= ~M_PKTHDR;
522 * Duplicate "from"'s mbuf pkthdr in "to".
523 * "from" must have M_PKTHDR set, and "to" must be empty.
524 * In particular, this does a deep copy of the packet tags.
527 m_dup_pkthdr(struct mbuf *to, struct mbuf *from, int how)
532 * The mbuf allocator only initializes the pkthdr
533 * when the mbuf is allocated with m_gethdr(). Many users
534 * (e.g. m_copy*, m_prepend) use m_get() and then
535 * smash the pkthdr as needed causing these
536 * assertions to trip. For now just disable them.
539 /* Note: with MAC, this may not be a good assertion. */
540 KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_dup_pkthdr: to has tags"));
542 MBUF_CHECKSLEEP(how);
544 if (to->m_flags & M_PKTHDR)
545 m_tag_delete_chain(to, NULL);
547 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
548 if ((to->m_flags & M_EXT) == 0)
549 to->m_data = to->m_pktdat;
550 to->m_pkthdr = from->m_pkthdr;
551 SLIST_INIT(&to->m_pkthdr.tags);
552 return (m_tag_copy_chain(to, from, how));
556 * Lesser-used path for M_PREPEND:
557 * allocate new mbuf to prepend to chain,
561 m_prepend(struct mbuf *m, int len, int how)
565 if (m->m_flags & M_PKTHDR)
566 mn = m_gethdr(how, m->m_type);
568 mn = m_get(how, m->m_type);
573 if (m->m_flags & M_PKTHDR)
574 m_move_pkthdr(mn, m);
577 if(m->m_flags & M_PKTHDR) {
589 * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
590 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf.
591 * The wait parameter is a choice of M_WAITOK/M_NOWAIT from caller.
592 * Note that the copy is read-only, because clusters are not copied,
593 * only their reference counts are incremented.
596 m_copym(struct mbuf *m, int off0, int len, int wait)
598 struct mbuf *n, **np;
603 KASSERT(off >= 0, ("m_copym, negative off %d", off));
604 KASSERT(len >= 0, ("m_copym, negative len %d", len));
605 MBUF_CHECKSLEEP(wait);
606 if (off == 0 && m->m_flags & M_PKTHDR)
609 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain"));
619 KASSERT(len == M_COPYALL,
620 ("m_copym, length > size of mbuf chain"));
624 n = m_gethdr(wait, m->m_type);
626 n = m_get(wait, m->m_type);
631 if (!m_dup_pkthdr(n, m, wait))
633 if (len == M_COPYALL)
634 n->m_pkthdr.len -= off0;
636 n->m_pkthdr.len = len;
639 n->m_len = min(len, m->m_len - off);
640 if (m->m_flags & M_EXT) {
641 n->m_data = m->m_data + off;
644 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
646 if (len != M_COPYALL)
660 * Returns mbuf chain with new head for the prepending case.
661 * Copies from mbuf (chain) n from off for len to mbuf (chain) m
662 * either prepending or appending the data.
663 * The resulting mbuf (chain) m is fully writeable.
664 * m is destination (is made writeable)
665 * n is source, off is offset in source, len is len from offset
666 * dir, 0 append, 1 prepend
667 * how, wait or nowait
671 m_bcopyxxx(void *s, void *t, u_int len)
673 bcopy(s, t, (size_t)len);
678 m_copymdata(struct mbuf *m, struct mbuf *n, int off, int len,
681 struct mbuf *mm, *x, *z, *prev = NULL;
686 KASSERT(m != NULL && n != NULL, ("m_copymdata, no target or source"));
687 KASSERT(off >= 0, ("m_copymdata, negative off %d", off));
688 KASSERT(len >= 0, ("m_copymdata, negative len %d", len));
689 KASSERT(prep == 0 || prep == 1, ("m_copymdata, unknown direction %d", prep));
698 for (z = n; z != NULL; z = z->m_next)
700 if (len == M_COPYALL)
702 if (off + len > nlen || len < 1)
705 if (!M_WRITABLE(mm)) {
706 /* XXX: Use proper m_xxx function instead. */
707 x = m_getcl(how, MT_DATA, mm->m_flags);
710 bcopy(mm->m_ext.ext_buf, x->m_ext.ext_buf, x->m_ext.ext_size);
711 p = x->m_ext.ext_buf + (mm->m_data - mm->m_ext.ext_buf);
721 * Append/prepend the data. Allocating mbufs as necessary.
723 /* Shortcut if enough free space in first/last mbuf. */
724 if (!prep && M_TRAILINGSPACE(mm) >= len) {
725 m_apply(n, off, len, m_bcopyxxx, mtod(mm, caddr_t) +
728 mm->m_pkthdr.len += len;
731 if (prep && M_LEADINGSPACE(mm) >= len) {
732 mm->m_data = mtod(mm, caddr_t) - len;
733 m_apply(n, off, len, m_bcopyxxx, mtod(mm, caddr_t));
735 mm->m_pkthdr.len += len;
739 /* Expand first/last mbuf to cluster if possible. */
740 if (!prep && !(mm->m_flags & M_EXT) && len > M_TRAILINGSPACE(mm)) {
741 bcopy(mm->m_data, &buf, mm->m_len);
743 if (!(mm->m_flags & M_EXT))
745 bcopy(&buf, mm->m_ext.ext_buf, mm->m_len);
746 mm->m_data = mm->m_ext.ext_buf;
748 if (prep && !(mm->m_flags & M_EXT) && len > M_LEADINGSPACE(mm)) {
749 bcopy(mm->m_data, &buf, mm->m_len);
751 if (!(mm->m_flags & M_EXT))
753 bcopy(&buf, (caddr_t *)mm->m_ext.ext_buf +
754 mm->m_ext.ext_size - mm->m_len, mm->m_len);
755 mm->m_data = (caddr_t)mm->m_ext.ext_buf +
756 mm->m_ext.ext_size - mm->m_len;
759 /* Append/prepend as many mbuf (clusters) as necessary to fit len. */
760 if (!prep && len > M_TRAILINGSPACE(mm)) {
761 if (!m_getm(mm, len - M_TRAILINGSPACE(mm), how, MT_DATA))
764 if (prep && len > M_LEADINGSPACE(mm)) {
765 if (!(z = m_getm(NULL, len - M_LEADINGSPACE(mm), how, MT_DATA)))
768 for (x = z; x != NULL; x = x->m_next) {
769 i += x->m_flags & M_EXT ? x->m_ext.ext_size :
770 (x->m_flags & M_PKTHDR ? MHLEN : MLEN);
774 z->m_data += i - len;
775 m_move_pkthdr(mm, z);
780 /* Seek to start position in source mbuf. Optimization for long chains. */
788 /* Copy data into target mbuf. */
791 KASSERT(z != NULL, ("m_copymdata, falling off target edge"));
792 i = M_TRAILINGSPACE(z);
793 m_apply(n, off, i, m_bcopyxxx, mtod(z, caddr_t) + z->m_len);
795 /* fixup pkthdr.len if necessary */
796 if ((prep ? mm : m)->m_flags & M_PKTHDR)
797 (prep ? mm : m)->m_pkthdr.len += i;
802 return (prep ? mm : m);
806 * Copy an entire packet, including header (which must be present).
807 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
808 * Note that the copy is read-only, because clusters are not copied,
809 * only their reference counts are incremented.
810 * Preserve alignment of the first mbuf so if the creator has left
811 * some room at the beginning (e.g. for inserting protocol headers)
812 * the copies still have the room available.
815 m_copypacket(struct mbuf *m, int how)
817 struct mbuf *top, *n, *o;
819 MBUF_CHECKSLEEP(how);
820 n = m_get(how, m->m_type);
825 if (!m_dup_pkthdr(n, m, how))
828 if (m->m_flags & M_EXT) {
829 n->m_data = m->m_data;
832 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat );
833 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
838 o = m_get(how, m->m_type);
846 if (m->m_flags & M_EXT) {
847 n->m_data = m->m_data;
850 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
862 * Copy data from an mbuf chain starting "off" bytes from the beginning,
863 * continuing for "len" bytes, into the indicated buffer.
866 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp)
870 KASSERT(off >= 0, ("m_copydata, negative off %d", off));
871 KASSERT(len >= 0, ("m_copydata, negative len %d", len));
873 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain"));
880 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain"));
881 count = min(m->m_len - off, len);
882 bcopy(mtod(m, caddr_t) + off, cp, count);
891 * Copy a packet header mbuf chain into a completely new chain, including
892 * copying any mbuf clusters. Use this instead of m_copypacket() when
893 * you need a writable copy of an mbuf chain.
896 m_dup(struct mbuf *m, int how)
898 struct mbuf **p, *top = NULL;
899 int remain, moff, nsize;
901 MBUF_CHECKSLEEP(how);
907 /* While there's more data, get a new mbuf, tack it on, and fill it */
908 remain = m->m_pkthdr.len;
911 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */
914 /* Get the next new mbuf */
915 if (remain >= MINCLSIZE) {
916 n = m_getcl(how, m->m_type, 0);
919 n = m_get(how, m->m_type);
925 if (top == NULL) { /* First one, must be PKTHDR */
926 if (!m_dup_pkthdr(n, m, how)) {
930 if ((n->m_flags & M_EXT) == 0)
935 /* Link it into the new chain */
939 /* Copy data from original mbuf(s) into new mbuf */
940 while (n->m_len < nsize && m != NULL) {
941 int chunk = min(nsize - n->m_len, m->m_len - moff);
943 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk);
947 if (moff == m->m_len) {
953 /* Check correct total mbuf length */
954 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL),
955 ("%s: bogus m_pkthdr.len", __func__));
965 * Concatenate mbuf chain n to m.
966 * Both chains must be of the same type (e.g. MT_DATA).
967 * Any m_pkthdr is not updated.
970 m_cat(struct mbuf *m, struct mbuf *n)
975 if (!M_WRITABLE(m) ||
976 M_TRAILINGSPACE(m) < n->m_len) {
977 /* just join the two chains */
981 /* splat the data from one into the other */
982 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
984 m->m_len += n->m_len;
990 * Concatenate two pkthdr mbuf chains.
993 m_catpkt(struct mbuf *m, struct mbuf *n)
999 m->m_pkthdr.len += n->m_pkthdr.len;
1006 m_adj(struct mbuf *mp, int req_len)
1012 if ((m = mp) == NULL)
1018 while (m != NULL && len > 0) {
1019 if (m->m_len <= len) {
1029 if (mp->m_flags & M_PKTHDR)
1030 mp->m_pkthdr.len -= (req_len - len);
1033 * Trim from tail. Scan the mbuf chain,
1034 * calculating its length and finding the last mbuf.
1035 * If the adjustment only affects this mbuf, then just
1036 * adjust and return. Otherwise, rescan and truncate
1037 * after the remaining size.
1043 if (m->m_next == (struct mbuf *)0)
1047 if (m->m_len >= len) {
1049 if (mp->m_flags & M_PKTHDR)
1050 mp->m_pkthdr.len -= len;
1057 * Correct length for chain is "count".
1058 * Find the mbuf with last data, adjust its length,
1059 * and toss data from remaining mbufs on chain.
1062 if (m->m_flags & M_PKTHDR)
1063 m->m_pkthdr.len = count;
1064 for (; m; m = m->m_next) {
1065 if (m->m_len >= count) {
1067 if (m->m_next != NULL) {
1079 * Rearange an mbuf chain so that len bytes are contiguous
1080 * and in the data area of an mbuf (so that mtod will work
1081 * for a structure of size len). Returns the resulting
1082 * mbuf chain on success, frees it and returns null on failure.
1083 * If there is room, it will add up to max_protohdr-len extra bytes to the
1084 * contiguous region in an attempt to avoid being called next time.
1087 m_pullup(struct mbuf *n, int len)
1094 * If first mbuf has no cluster, and has room for len bytes
1095 * without shifting current data, pullup into it,
1096 * otherwise allocate a new mbuf to prepend to the chain.
1098 if ((n->m_flags & M_EXT) == 0 &&
1099 n->m_data + len < &n->m_dat[MLEN] && n->m_next) {
1100 if (n->m_len >= len)
1108 m = m_get(M_NOWAIT, n->m_type);
1111 if (n->m_flags & M_PKTHDR)
1112 m_move_pkthdr(m, n);
1114 space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
1116 count = min(min(max(len, max_protohdr), space), n->m_len);
1117 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1127 } while (len > 0 && n);
1140 * Like m_pullup(), except a new mbuf is always allocated, and we allow
1141 * the amount of empty space before the data in the new mbuf to be specified
1142 * (in the event that the caller expects to prepend later).
1147 m_copyup(struct mbuf *n, int len, int dstoff)
1152 if (len > (MHLEN - dstoff))
1154 m = m_get(M_NOWAIT, n->m_type);
1157 if (n->m_flags & M_PKTHDR)
1158 m_move_pkthdr(m, n);
1159 m->m_data += dstoff;
1160 space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
1162 count = min(min(max(len, max_protohdr), space), n->m_len);
1163 memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t),
1173 } while (len > 0 && n);
1187 * Partition an mbuf chain in two pieces, returning the tail --
1188 * all but the first len0 bytes. In case of failure, it returns NULL and
1189 * attempts to restore the chain to its original state.
1191 * Note that the resulting mbufs might be read-only, because the new
1192 * mbuf can end up sharing an mbuf cluster with the original mbuf if
1193 * the "breaking point" happens to lie within a cluster mbuf. Use the
1194 * M_WRITABLE() macro to check for this case.
1197 m_split(struct mbuf *m0, int len0, int wait)
1200 u_int len = len0, remain;
1202 MBUF_CHECKSLEEP(wait);
1203 for (m = m0; m && len > m->m_len; m = m->m_next)
1207 remain = m->m_len - len;
1208 if (m0->m_flags & M_PKTHDR && remain == 0) {
1209 n = m_gethdr(wait, m0->m_type);
1212 n->m_next = m->m_next;
1214 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
1215 n->m_pkthdr.len = m0->m_pkthdr.len - len0;
1216 m0->m_pkthdr.len = len0;
1218 } else if (m0->m_flags & M_PKTHDR) {
1219 n = m_gethdr(wait, m0->m_type);
1222 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
1223 n->m_pkthdr.len = m0->m_pkthdr.len - len0;
1224 m0->m_pkthdr.len = len0;
1225 if (m->m_flags & M_EXT)
1227 if (remain > MHLEN) {
1228 /* m can't be the lead packet */
1230 n->m_next = m_split(m, len, wait);
1231 if (n->m_next == NULL) {
1239 MH_ALIGN(n, remain);
1240 } else if (remain == 0) {
1245 n = m_get(wait, m->m_type);
1251 if (m->m_flags & M_EXT) {
1252 n->m_data = m->m_data + len;
1255 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain);
1259 n->m_next = m->m_next;
1264 * Routine to copy from device local memory into mbufs.
1265 * Note that `off' argument is offset into first mbuf of target chain from
1266 * which to begin copying the data to.
1269 m_devget(char *buf, int totlen, int off, struct ifnet *ifp,
1270 void (*copy)(char *from, caddr_t to, u_int len))
1273 struct mbuf *top = NULL, **mp = ⊤
1276 if (off < 0 || off > MHLEN)
1279 while (totlen > 0) {
1280 if (top == NULL) { /* First one, must be PKTHDR */
1281 if (totlen + off >= MINCLSIZE) {
1282 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
1285 m = m_gethdr(M_NOWAIT, MT_DATA);
1288 /* Place initial small packet/header at end of mbuf */
1289 if (m && totlen + off + max_linkhdr <= MLEN) {
1290 m->m_data += max_linkhdr;
1296 m->m_pkthdr.rcvif = ifp;
1297 m->m_pkthdr.len = totlen;
1299 if (totlen + off >= MINCLSIZE) {
1300 m = m_getcl(M_NOWAIT, MT_DATA, 0);
1303 m = m_get(M_NOWAIT, MT_DATA);
1316 m->m_len = len = min(totlen, len);
1318 copy(buf, mtod(m, caddr_t), (u_int)len);
1320 bcopy(buf, mtod(m, caddr_t), (u_int)len);
1330 * Copy data from a buffer back into the indicated mbuf chain,
1331 * starting "off" bytes from the beginning, extending the mbuf
1332 * chain if necessary.
1335 m_copyback(struct mbuf *m0, int off, int len, c_caddr_t cp)
1338 struct mbuf *m = m0, *n;
1343 while (off > (mlen = m->m_len)) {
1346 if (m->m_next == NULL) {
1347 n = m_get(M_NOWAIT, m->m_type);
1350 bzero(mtod(n, caddr_t), MLEN);
1351 n->m_len = min(MLEN, len + off);
1357 if (m->m_next == NULL && (len > m->m_len - off)) {
1358 m->m_len += min(len - (m->m_len - off),
1359 M_TRAILINGSPACE(m));
1361 mlen = min (m->m_len - off, len);
1362 bcopy(cp, off + mtod(m, caddr_t), (u_int)mlen);
1370 if (m->m_next == NULL) {
1371 n = m_get(M_NOWAIT, m->m_type);
1374 n->m_len = min(MLEN, len);
1379 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
1380 m->m_pkthdr.len = totlen;
1384 * Append the specified data to the indicated mbuf chain,
1385 * Extend the mbuf chain if the new data does not fit in
1388 * Return 1 if able to complete the job; otherwise 0.
1391 m_append(struct mbuf *m0, int len, c_caddr_t cp)
1394 int remainder, space;
1396 for (m = m0; m->m_next != NULL; m = m->m_next)
1399 space = M_TRAILINGSPACE(m);
1402 * Copy into available space.
1404 if (space > remainder)
1406 bcopy(cp, mtod(m, caddr_t) + m->m_len, space);
1408 cp += space, remainder -= space;
1410 while (remainder > 0) {
1412 * Allocate a new mbuf; could check space
1413 * and allocate a cluster instead.
1415 n = m_get(M_NOWAIT, m->m_type);
1418 n->m_len = min(MLEN, remainder);
1419 bcopy(cp, mtod(n, caddr_t), n->m_len);
1420 cp += n->m_len, remainder -= n->m_len;
1424 if (m0->m_flags & M_PKTHDR)
1425 m0->m_pkthdr.len += len - remainder;
1426 return (remainder == 0);
1430 * Apply function f to the data in an mbuf chain starting "off" bytes from
1431 * the beginning, continuing for "len" bytes.
1434 m_apply(struct mbuf *m, int off, int len,
1435 int (*f)(void *, void *, u_int), void *arg)
1440 KASSERT(off >= 0, ("m_apply, negative off %d", off));
1441 KASSERT(len >= 0, ("m_apply, negative len %d", len));
1443 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
1450 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
1451 count = min(m->m_len - off, len);
1452 rval = (*f)(arg, mtod(m, caddr_t) + off, count);
1463 * Return a pointer to mbuf/offset of location in mbuf chain.
1466 m_getptr(struct mbuf *m, int loc, int *off)
1470 /* Normal end of search. */
1471 if (m->m_len > loc) {
1476 if (m->m_next == NULL) {
1478 /* Point at the end of valid data. */
1491 m_print(const struct mbuf *m, int maxlen)
1495 const struct mbuf *m2;
1498 printf("mbuf: %p\n", m);
1502 if (m->m_flags & M_PKTHDR)
1503 len = m->m_pkthdr.len;
1507 while (m2 != NULL && (len == -1 || len)) {
1509 if (maxlen != -1 && pdata > maxlen)
1511 printf("mbuf: %p len: %d, next: %p, %b%s", m2, m2->m_len,
1512 m2->m_next, m2->m_flags, "\20\20freelist\17skipfw"
1513 "\11proto5\10proto4\7proto3\6proto2\5proto1\4rdonly"
1514 "\3eor\2pkthdr\1ext", pdata ? "" : "\n");
1516 printf(", %*D\n", pdata, (u_char *)m2->m_data, "-");
1522 printf("%d bytes unaccounted for.\n", len);
1527 m_fixhdr(struct mbuf *m0)
1531 len = m_length(m0, NULL);
1532 m0->m_pkthdr.len = len;
1537 m_length(struct mbuf *m0, struct mbuf **last)
1543 for (m = m0; m != NULL; m = m->m_next) {
1545 if (m->m_next == NULL)
1554 * Defragment a mbuf chain, returning the shortest possible
1555 * chain of mbufs and clusters. If allocation fails and
1556 * this cannot be completed, NULL will be returned, but
1557 * the passed in chain will be unchanged. Upon success,
1558 * the original chain will be freed, and the new chain
1561 * If a non-packet header is passed in, the original
1562 * mbuf (chain?) will be returned unharmed.
1565 m_defrag(struct mbuf *m0, int how)
1567 struct mbuf *m_new = NULL, *m_final = NULL;
1568 int progress = 0, length;
1570 MBUF_CHECKSLEEP(how);
1571 if (!(m0->m_flags & M_PKTHDR))
1574 m_fixhdr(m0); /* Needed sanity check */
1576 #ifdef MBUF_STRESS_TEST
1577 if (m_defragrandomfailures) {
1578 int temp = arc4random() & 0xff;
1584 if (m0->m_pkthdr.len > MHLEN)
1585 m_final = m_getcl(how, MT_DATA, M_PKTHDR);
1587 m_final = m_gethdr(how, MT_DATA);
1589 if (m_final == NULL)
1592 if (m_dup_pkthdr(m_final, m0, how) == 0)
1597 while (progress < m0->m_pkthdr.len) {
1598 length = m0->m_pkthdr.len - progress;
1599 if (length > MCLBYTES)
1602 if (m_new == NULL) {
1604 m_new = m_getcl(how, MT_DATA, 0);
1606 m_new = m_get(how, MT_DATA);
1611 m_copydata(m0, progress, length, mtod(m_new, caddr_t));
1613 m_new->m_len = length;
1614 if (m_new != m_final)
1615 m_cat(m_final, m_new);
1618 #ifdef MBUF_STRESS_TEST
1619 if (m0->m_next == NULL)
1624 #ifdef MBUF_STRESS_TEST
1626 m_defragbytes += m0->m_pkthdr.len;
1630 #ifdef MBUF_STRESS_TEST
1639 * Defragment an mbuf chain, returning at most maxfrags separate
1640 * mbufs+clusters. If this is not possible NULL is returned and
1641 * the original mbuf chain is left in it's present (potentially
1642 * modified) state. We use two techniques: collapsing consecutive
1643 * mbufs and replacing consecutive mbufs by a cluster.
1645 * NB: this should really be named m_defrag but that name is taken
1648 m_collapse(struct mbuf *m0, int how, int maxfrags)
1650 struct mbuf *m, *n, *n2, **prev;
1654 * Calculate the current number of frags.
1657 for (m = m0; m != NULL; m = m->m_next)
1660 * First, try to collapse mbufs. Note that we always collapse
1661 * towards the front so we don't need to deal with moving the
1662 * pkthdr. This may be suboptimal if the first mbuf has much
1663 * less data than the following.
1671 if (M_WRITABLE(m) &&
1672 n->m_len < M_TRAILINGSPACE(m)) {
1673 bcopy(mtod(n, void *), mtod(m, char *) + m->m_len,
1675 m->m_len += n->m_len;
1676 m->m_next = n->m_next;
1678 if (--curfrags <= maxfrags)
1683 KASSERT(maxfrags > 1,
1684 ("maxfrags %u, but normal collapse failed", maxfrags));
1686 * Collapse consecutive mbufs to a cluster.
1688 prev = &m0->m_next; /* NB: not the first mbuf */
1689 while ((n = *prev) != NULL) {
1690 if ((n2 = n->m_next) != NULL &&
1691 n->m_len + n2->m_len < MCLBYTES) {
1692 m = m_getcl(how, MT_DATA, 0);
1695 bcopy(mtod(n, void *), mtod(m, void *), n->m_len);
1696 bcopy(mtod(n2, void *), mtod(m, char *) + n->m_len,
1698 m->m_len = n->m_len + n2->m_len;
1699 m->m_next = n2->m_next;
1703 if (--curfrags <= maxfrags) /* +1 cl -2 mbufs */
1706 * Still not there, try the normal collapse
1707 * again before we allocate another cluster.
1714 * No place where we can collapse to a cluster; punt.
1715 * This can occur if, for example, you request 2 frags
1716 * but the packet requires that both be clusters (we
1717 * never reallocate the first mbuf to avoid moving the
1724 #ifdef MBUF_STRESS_TEST
1727 * Fragment an mbuf chain. There's no reason you'd ever want to do
1728 * this in normal usage, but it's great for stress testing various
1731 * If fragmentation is not possible, the original chain will be
1734 * Possible length values:
1735 * 0 no fragmentation will occur
1736 * > 0 each fragment will be of the specified length
1737 * -1 each fragment will be the same random value in length
1738 * -2 each fragment's length will be entirely random
1739 * (Random values range from 1 to 256)
1742 m_fragment(struct mbuf *m0, int how, int length)
1744 struct mbuf *m_new = NULL, *m_final = NULL;
1747 if (!(m0->m_flags & M_PKTHDR))
1750 if ((length == 0) || (length < -2))
1753 m_fixhdr(m0); /* Needed sanity check */
1755 m_final = m_getcl(how, MT_DATA, M_PKTHDR);
1757 if (m_final == NULL)
1760 if (m_dup_pkthdr(m_final, m0, how) == 0)
1766 length = 1 + (arc4random() & 255);
1768 while (progress < m0->m_pkthdr.len) {
1774 fraglen = 1 + (arc4random() & 255);
1775 if (fraglen > m0->m_pkthdr.len - progress)
1776 fraglen = m0->m_pkthdr.len - progress;
1778 if (fraglen > MCLBYTES)
1781 if (m_new == NULL) {
1782 m_new = m_getcl(how, MT_DATA, 0);
1787 m_copydata(m0, progress, fraglen, mtod(m_new, caddr_t));
1788 progress += fraglen;
1789 m_new->m_len = fraglen;
1790 if (m_new != m_final)
1791 m_cat(m_final, m_new);
1800 /* Return the original chain on failure */
1807 * Copy the contents of uio into a properly sized mbuf chain.
1810 m_uiotombuf(struct uio *uio, int how, int len, int align, int flags)
1812 struct mbuf *m, *mb;
1818 * len can be zero or an arbitrary large value bound by
1819 * the total data supplied by the uio.
1822 total = min(uio->uio_resid, len);
1824 total = uio->uio_resid;
1827 * The smallest unit returned by m_getm2() is a single mbuf
1828 * with pkthdr. We can't align past it.
1834 * Give us the full allocation or nothing.
1835 * If len is zero return the smallest empty mbuf.
1837 m = m_getm2(NULL, max(total + align, 1), how, MT_DATA, flags);
1842 /* Fill all mbufs with uio data and update header information. */
1843 for (mb = m; mb != NULL; mb = mb->m_next) {
1844 length = min(M_TRAILINGSPACE(mb), total - progress);
1846 error = uiomove(mtod(mb, void *), length, uio);
1854 if (flags & M_PKTHDR)
1855 m->m_pkthdr.len += length;
1857 KASSERT(progress == total, ("%s: progress != total", __func__));
1863 * Copy an mbuf chain into a uio limited by len if set.
1866 m_mbuftouio(struct uio *uio, struct mbuf *m, int len)
1868 int error, length, total;
1872 total = min(uio->uio_resid, len);
1874 total = uio->uio_resid;
1876 /* Fill the uio with data from the mbufs. */
1877 for (; m != NULL; m = m->m_next) {
1878 length = min(m->m_len, total - progress);
1880 error = uiomove(mtod(m, void *), length, uio);
1891 * Set the m_data pointer of a newly-allocated mbuf
1892 * to place an object of the specified size at the
1893 * end of the mbuf, longword aligned.
1896 m_align(struct mbuf *m, int len)
1899 const char *msg = "%s: not a virgin mbuf";
1903 if (m->m_flags & M_EXT) {
1904 KASSERT(m->m_data == m->m_ext.ext_buf, (msg, __func__));
1905 adjust = m->m_ext.ext_size - len;
1906 } else if (m->m_flags & M_PKTHDR) {
1907 KASSERT(m->m_data == m->m_pktdat, (msg, __func__));
1908 adjust = MHLEN - len;
1910 KASSERT(m->m_data == m->m_dat, (msg, __func__));
1911 adjust = MLEN - len;
1914 m->m_data += adjust &~ (sizeof(long)-1);
1918 * Create a writable copy of the mbuf chain. While doing this
1919 * we compact the chain with a goal of producing a chain with
1920 * at most two mbufs. The second mbuf in this chain is likely
1921 * to be a cluster. The primary purpose of this work is to create
1922 * a writable packet for encryption, compression, etc. The
1923 * secondary goal is to linearize the data so the data can be
1924 * passed to crypto hardware in the most efficient manner possible.
1927 m_unshare(struct mbuf *m0, int how)
1929 struct mbuf *m, *mprev;
1930 struct mbuf *n, *mfirst, *mlast;
1934 for (m = m0; m != NULL; m = mprev->m_next) {
1936 * Regular mbufs are ignored unless there's a cluster
1937 * in front of it that we can use to coalesce. We do
1938 * the latter mainly so later clusters can be coalesced
1939 * also w/o having to handle them specially (i.e. convert
1940 * mbuf+cluster -> cluster). This optimization is heavily
1941 * influenced by the assumption that we're running over
1942 * Ethernet where MCLBYTES is large enough that the max
1943 * packet size will permit lots of coalescing into a
1944 * single cluster. This in turn permits efficient
1945 * crypto operations, especially when using hardware.
1947 if ((m->m_flags & M_EXT) == 0) {
1948 if (mprev && (mprev->m_flags & M_EXT) &&
1949 m->m_len <= M_TRAILINGSPACE(mprev)) {
1950 /* XXX: this ignores mbuf types */
1951 memcpy(mtod(mprev, caddr_t) + mprev->m_len,
1952 mtod(m, caddr_t), m->m_len);
1953 mprev->m_len += m->m_len;
1954 mprev->m_next = m->m_next; /* unlink from chain */
1955 m_free(m); /* reclaim mbuf */
1957 newipsecstat.ips_mbcoalesced++;
1965 * Writable mbufs are left alone (for now).
1967 if (M_WRITABLE(m)) {
1973 * Not writable, replace with a copy or coalesce with
1974 * the previous mbuf if possible (since we have to copy
1975 * it anyway, we try to reduce the number of mbufs and
1976 * clusters so that future work is easier).
1978 KASSERT(m->m_flags & M_EXT, ("m_flags 0x%x", m->m_flags));
1979 /* NB: we only coalesce into a cluster or larger */
1980 if (mprev != NULL && (mprev->m_flags & M_EXT) &&
1981 m->m_len <= M_TRAILINGSPACE(mprev)) {
1982 /* XXX: this ignores mbuf types */
1983 memcpy(mtod(mprev, caddr_t) + mprev->m_len,
1984 mtod(m, caddr_t), m->m_len);
1985 mprev->m_len += m->m_len;
1986 mprev->m_next = m->m_next; /* unlink from chain */
1987 m_free(m); /* reclaim mbuf */
1989 newipsecstat.ips_clcoalesced++;
1995 * Allocate new space to hold the copy and copy the data.
1996 * We deal with jumbo mbufs (i.e. m_len > MCLBYTES) by
1997 * splitting them into clusters. We could just malloc a
1998 * buffer and make it external but too many device drivers
1999 * don't know how to break up the non-contiguous memory when
2002 n = m_getcl(how, m->m_type, m->m_flags);
2012 int cc = min(len, MCLBYTES);
2013 memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, cc);
2019 newipsecstat.ips_clcopied++;
2027 n = m_getcl(how, m->m_type, m->m_flags);
2034 n->m_next = m->m_next;
2036 m0 = mfirst; /* new head of chain */
2038 mprev->m_next = mfirst; /* replace old mbuf */
2039 m_free(m); /* release old mbuf */
2045 #ifdef MBUF_PROFILING
2047 #define MP_BUCKETS 32 /* don't just change this as things may overflow.*/
2048 struct mbufprofile {
2049 uintmax_t wasted[MP_BUCKETS];
2050 uintmax_t used[MP_BUCKETS];
2051 uintmax_t segments[MP_BUCKETS];
2054 #define MP_MAXDIGITS 21 /* strlen("16,000,000,000,000,000,000") == 21 */
2055 #define MP_NUMLINES 6
2056 #define MP_NUMSPERLINE 16
2057 #define MP_EXTRABYTES 64 /* > strlen("used:\nwasted:\nsegments:\n") */
2058 /* work out max space needed and add a bit of spare space too */
2059 #define MP_MAXLINE ((MP_MAXDIGITS+1) * MP_NUMSPERLINE)
2060 #define MP_BUFSIZE ((MP_MAXLINE * MP_NUMLINES) + 1 + MP_EXTRABYTES)
2062 char mbprofbuf[MP_BUFSIZE];
2065 m_profile(struct mbuf *m)
2074 if (m->m_flags & M_EXT) {
2075 wasted += MHLEN - sizeof(m->m_ext) +
2076 m->m_ext.ext_size - m->m_len;
2078 if (m->m_flags & M_PKTHDR)
2079 wasted += MHLEN - m->m_len;
2081 wasted += MLEN - m->m_len;
2085 /* be paranoid.. it helps */
2086 if (segments > MP_BUCKETS - 1)
2087 segments = MP_BUCKETS - 1;
2090 if (wasted > 100000)
2092 /* store in the appropriate bucket */
2093 /* don't bother locking. if it's slightly off, so what? */
2094 mbprof.segments[segments]++;
2095 mbprof.used[fls(used)]++;
2096 mbprof.wasted[fls(wasted)]++;
2100 mbprof_textify(void)
2106 p = &mbprof.wasted[0];
2108 offset = snprintf(c, MP_MAXLINE + 10,
2110 "%ju %ju %ju %ju %ju %ju %ju %ju "
2111 "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2112 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2113 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2115 p = &mbprof.wasted[16];
2117 offset = snprintf(c, MP_MAXLINE,
2118 "%ju %ju %ju %ju %ju %ju %ju %ju "
2119 "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2120 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2121 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2123 p = &mbprof.used[0];
2125 offset = snprintf(c, MP_MAXLINE + 10,
2127 "%ju %ju %ju %ju %ju %ju %ju %ju "
2128 "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2129 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2130 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2132 p = &mbprof.used[16];
2134 offset = snprintf(c, MP_MAXLINE,
2135 "%ju %ju %ju %ju %ju %ju %ju %ju "
2136 "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2137 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2138 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2140 p = &mbprof.segments[0];
2142 offset = snprintf(c, MP_MAXLINE + 10,
2144 "%ju %ju %ju %ju %ju %ju %ju %ju "
2145 "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2146 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2147 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2149 p = &mbprof.segments[16];
2151 offset = snprintf(c, MP_MAXLINE,
2152 "%ju %ju %ju %ju %ju %ju %ju %ju "
2153 "%ju %ju %ju %ju %ju %ju %ju %jju",
2154 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2155 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2160 mbprof_handler(SYSCTL_HANDLER_ARGS)
2165 error = SYSCTL_OUT(req, mbprofbuf, strlen(mbprofbuf) + 1);
2170 mbprof_clr_handler(SYSCTL_HANDLER_ARGS)
2175 error = sysctl_handle_int(oidp, &clear, 0, req);
2176 if (error || !req->newptr)
2180 bzero(&mbprof, sizeof(mbprof));
2187 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofile, CTLTYPE_STRING|CTLFLAG_RD,
2188 NULL, 0, mbprof_handler, "A", "mbuf profiling statistics");
2190 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofileclr, CTLTYPE_INT|CTLFLAG_RW,
2191 NULL, 0, mbprof_clr_handler, "I", "clear mbuf profiling statistics");