2 * Copyright (c) 2004 Jeffrey M. Hsu. All rights reserved.
3 * Copyright (c) 2004 The DragonFly Project. All rights reserved.
5 * This code is derived from software contributed to The DragonFly Project
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of The DragonFly Project nor the names of its
17 * contributors may be used to endorse or promote products derived
18 * from this software without specific, prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * Copyright (c) 1982, 1986, 1988, 1991, 1993
36 * The Regents of the University of California. All rights reserved.
38 * Redistribution and use in source and binary forms, with or without
39 * modification, are permitted provided that the following conditions
41 * 1. Redistributions of source code must retain the above copyright
42 * notice, this list of conditions and the following disclaimer.
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48 * This product includes software developed by the University of
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50 * 4. Neither the name of the University nor the names of its contributors
51 * may be used to endorse or promote products derived from this software
52 * without specific prior written permission.
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59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
66 * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94
67 * $FreeBSD: src/sys/kern/uipc_mbuf.c,v 1.51.2.24 2003/04/15 06:59:29 silby Exp $
68 * $DragonFly: src/sys/kern/uipc_mbuf.c,v 1.61 2007/04/30 07:18:54 dillon Exp $
71 #include "opt_param.h"
73 #include "opt_mbuf_stress_test.h"
74 #include <sys/param.h>
75 #include <sys/systm.h>
76 #include <sys/malloc.h>
78 #include <sys/kernel.h>
79 #include <sys/sysctl.h>
80 #include <sys/domain.h>
81 #include <sys/objcache.h>
82 #include <sys/protosw.h>
84 #include <sys/thread.h>
85 #include <sys/globaldata.h>
86 #include <sys/serialize.h>
87 #include <sys/thread2.h>
90 #include <vm/vm_kern.h>
91 #include <vm/vm_extern.h>
94 #include <machine/cpu.h>
98 * mbuf cluster meta-data
103 struct lwkt_serialize mcl_serializer
;
106 static void mbinit(void *);
107 SYSINIT(mbuf
, SI_BOOT2_MACHDEP
, SI_ORDER_FIRST
, mbinit
, NULL
)
109 static u_long mbtypes
[MT_NTYPES
];
111 struct mbstat mbstat
;
120 #ifdef MBUF_STRESS_TEST
121 int m_defragrandomfailures
;
124 struct objcache
*mbuf_cache
, *mbufphdr_cache
;
125 struct objcache
*mclmeta_cache
;
126 struct objcache
*mbufcluster_cache
, *mbufphdrcluster_cache
;
131 SYSCTL_INT(_kern_ipc
, KIPC_MAX_LINKHDR
, max_linkhdr
, CTLFLAG_RW
,
132 &max_linkhdr
, 0, "");
133 SYSCTL_INT(_kern_ipc
, KIPC_MAX_PROTOHDR
, max_protohdr
, CTLFLAG_RW
,
134 &max_protohdr
, 0, "");
135 SYSCTL_INT(_kern_ipc
, KIPC_MAX_HDR
, max_hdr
, CTLFLAG_RW
, &max_hdr
, 0, "");
136 SYSCTL_INT(_kern_ipc
, KIPC_MAX_DATALEN
, max_datalen
, CTLFLAG_RW
,
137 &max_datalen
, 0, "");
138 SYSCTL_INT(_kern_ipc
, OID_AUTO
, mbuf_wait
, CTLFLAG_RW
,
140 SYSCTL_STRUCT(_kern_ipc
, KIPC_MBSTAT
, mbstat
, CTLFLAG_RW
, &mbstat
, mbstat
, "");
141 SYSCTL_OPAQUE(_kern_ipc
, OID_AUTO
, mbtypes
, CTLFLAG_RD
, mbtypes
,
142 sizeof(mbtypes
), "LU", "");
143 SYSCTL_INT(_kern_ipc
, KIPC_NMBCLUSTERS
, nmbclusters
, CTLFLAG_RW
,
144 &nmbclusters
, 0, "Maximum number of mbuf clusters available");
145 SYSCTL_INT(_kern_ipc
, OID_AUTO
, nmbufs
, CTLFLAG_RW
, &nmbufs
, 0,
146 "Maximum number of mbufs available");
148 SYSCTL_INT(_kern_ipc
, OID_AUTO
, m_defragpackets
, CTLFLAG_RD
,
149 &m_defragpackets
, 0, "");
150 SYSCTL_INT(_kern_ipc
, OID_AUTO
, m_defragbytes
, CTLFLAG_RD
,
151 &m_defragbytes
, 0, "");
152 SYSCTL_INT(_kern_ipc
, OID_AUTO
, m_defraguseless
, CTLFLAG_RD
,
153 &m_defraguseless
, 0, "");
154 SYSCTL_INT(_kern_ipc
, OID_AUTO
, m_defragfailure
, CTLFLAG_RD
,
155 &m_defragfailure
, 0, "");
156 #ifdef MBUF_STRESS_TEST
157 SYSCTL_INT(_kern_ipc
, OID_AUTO
, m_defragrandomfailures
, CTLFLAG_RW
,
158 &m_defragrandomfailures
, 0, "");
161 static MALLOC_DEFINE(M_MBUF
, "mbuf", "mbuf");
162 static MALLOC_DEFINE(M_MBUFCL
, "mbufcl", "mbufcl");
163 static MALLOC_DEFINE(M_MCLMETA
, "mclmeta", "mclmeta");
165 static void m_reclaim (void);
166 static void m_mclref(void *arg
);
167 static void m_mclfree(void *arg
);
170 #define NMBCLUSTERS (512 + maxusers * 16)
173 #define NMBUFS (nmbclusters * 2)
177 * Perform sanity checks of tunables declared above.
180 tunable_mbinit(void *dummy
)
183 * This has to be done before VM init.
185 nmbclusters
= NMBCLUSTERS
;
186 TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters
);
188 TUNABLE_INT_FETCH("kern.ipc.nmbufs", &nmbufs
);
190 if (nmbufs
< nmbclusters
* 2)
191 nmbufs
= nmbclusters
* 2;
193 SYSINIT(tunable_mbinit
, SI_BOOT1_TUNABLES
, SI_ORDER_ANY
,
194 tunable_mbinit
, NULL
);
196 /* "number of clusters of pages" */
202 * The mbuf object cache only guarantees that m_next and m_nextpkt are
203 * NULL and that m_data points to the beginning of the data area. In
204 * particular, m_len and m_pkthdr.len are uninitialized. It is the
205 * responsibility of the caller to initialize those fields before use.
208 static boolean_t __inline
209 mbuf_ctor(void *obj
, void *private, int ocflags
)
211 struct mbuf
*m
= obj
;
215 m
->m_data
= m
->m_dat
;
222 * Initialize the mbuf and the packet header fields.
225 mbufphdr_ctor(void *obj
, void *private, int ocflags
)
227 struct mbuf
*m
= obj
;
231 m
->m_data
= m
->m_pktdat
;
232 m
->m_flags
= M_PKTHDR
| M_PHCACHE
;
234 m
->m_pkthdr
.rcvif
= NULL
; /* eliminate XXX JH */
235 SLIST_INIT(&m
->m_pkthdr
.tags
);
236 m
->m_pkthdr
.csum_flags
= 0; /* eliminate XXX JH */
237 m
->m_pkthdr
.fw_flags
= 0; /* eliminate XXX JH */
243 * A mbcluster object consists of 2K (MCLBYTES) cluster and a refcount.
246 mclmeta_ctor(void *obj
, void *private, int ocflags
)
248 struct mbcluster
*cl
= obj
;
251 if (ocflags
& M_NOWAIT
)
252 buf
= kmalloc(MCLBYTES
, M_MBUFCL
, M_NOWAIT
| M_ZERO
);
254 buf
= kmalloc(MCLBYTES
, M_MBUFCL
, M_INTWAIT
| M_ZERO
);
259 lwkt_serialize_init(&cl
->mcl_serializer
);
264 mclmeta_dtor(void *obj
, void *private)
266 struct mbcluster
*mcl
= obj
;
268 KKASSERT(mcl
->mcl_refs
== 0);
269 kfree(mcl
->mcl_data
, M_MBUFCL
);
273 linkcluster(struct mbuf
*m
, struct mbcluster
*cl
)
276 * Add the cluster to the mbuf. The caller will detect that the
277 * mbuf now has an attached cluster.
279 m
->m_ext
.ext_arg
= cl
;
280 m
->m_ext
.ext_buf
= cl
->mcl_data
;
281 m
->m_ext
.ext_ref
= m_mclref
;
282 m
->m_ext
.ext_free
= m_mclfree
;
283 m
->m_ext
.ext_size
= MCLBYTES
;
284 atomic_add_int(&cl
->mcl_refs
, 1);
286 m
->m_data
= m
->m_ext
.ext_buf
;
287 m
->m_flags
|= M_EXT
| M_EXT_CLUSTER
;
291 mbufphdrcluster_ctor(void *obj
, void *private, int ocflags
)
293 struct mbuf
*m
= obj
;
294 struct mbcluster
*cl
;
296 mbufphdr_ctor(obj
, private, ocflags
);
297 cl
= objcache_get(mclmeta_cache
, ocflags
);
300 m
->m_flags
|= M_CLCACHE
;
306 mbufcluster_ctor(void *obj
, void *private, int ocflags
)
308 struct mbuf
*m
= obj
;
309 struct mbcluster
*cl
;
311 mbuf_ctor(obj
, private, ocflags
);
312 cl
= objcache_get(mclmeta_cache
, ocflags
);
315 m
->m_flags
|= M_CLCACHE
;
321 * Used for both the cluster and cluster PHDR caches.
323 * The mbuf may have lost its cluster due to sharing, deal
324 * with the situation by checking M_EXT.
327 mbufcluster_dtor(void *obj
, void *private)
329 struct mbuf
*m
= obj
;
330 struct mbcluster
*mcl
;
332 if (m
->m_flags
& M_EXT
) {
333 KKASSERT((m
->m_flags
& M_EXT_CLUSTER
) != 0);
334 mcl
= m
->m_ext
.ext_arg
;
335 KKASSERT(mcl
->mcl_refs
== 1);
337 objcache_put(mclmeta_cache
, mcl
);
341 struct objcache_malloc_args mbuf_malloc_args
= { MSIZE
, M_MBUF
};
342 struct objcache_malloc_args mclmeta_malloc_args
=
343 { sizeof(struct mbcluster
), M_MCLMETA
};
349 mbstat
.m_msize
= MSIZE
;
350 mbstat
.m_mclbytes
= MCLBYTES
;
351 mbstat
.m_minclsize
= MINCLSIZE
;
352 mbstat
.m_mlen
= MLEN
;
353 mbstat
.m_mhlen
= MHLEN
;
355 mbuf_cache
= objcache_create("mbuf", nmbufs
, 0,
356 mbuf_ctor
, NULL
, NULL
,
357 objcache_malloc_alloc
, objcache_malloc_free
, &mbuf_malloc_args
);
358 mbufphdr_cache
= objcache_create("mbuf pkt hdr", nmbufs
, 64,
359 mbufphdr_ctor
, NULL
, NULL
,
360 objcache_malloc_alloc
, objcache_malloc_free
, &mbuf_malloc_args
);
361 mclmeta_cache
= objcache_create("cluster mbuf", nmbclusters
, 0,
362 mclmeta_ctor
, mclmeta_dtor
, NULL
,
363 objcache_malloc_alloc
, objcache_malloc_free
, &mclmeta_malloc_args
);
364 mbufcluster_cache
= objcache_create("mbuf + cluster", nmbclusters
, 0,
365 mbufcluster_ctor
, mbufcluster_dtor
, NULL
,
366 objcache_malloc_alloc
, objcache_malloc_free
, &mbuf_malloc_args
);
367 mbufphdrcluster_cache
= objcache_create("mbuf pkt hdr + cluster",
368 nmbclusters
, 64, mbufphdrcluster_ctor
, mbufcluster_dtor
, NULL
,
369 objcache_malloc_alloc
, objcache_malloc_free
, &mbuf_malloc_args
);
374 * Return the number of references to this mbuf's data. 0 is returned
375 * if the mbuf is not M_EXT, a reference count is returned if it is
376 * M_EXT | M_EXT_CLUSTER, and 99 is returned if it is a special M_EXT.
379 m_sharecount(struct mbuf
*m
)
381 switch (m
->m_flags
& (M_EXT
| M_EXT_CLUSTER
)) {
386 case M_EXT
| M_EXT_CLUSTER
:
387 return (((struct mbcluster
*)m
->m_ext
.ext_arg
)->mcl_refs
);
390 return (0); /* to shut up compiler */
394 * change mbuf to new type
397 m_chtype(struct mbuf
*m
, int type
)
401 --mbtypes
[m
->m_type
];
413 SLIST_FOREACH(dp
, &domains
, dom_next
) {
414 for (pr
= dp
->dom_protosw
; pr
< dp
->dom_protoswNPROTOSW
; pr
++) {
424 updatestats(struct mbuf
*m
, int type
)
438 m_get(int how
, int type
)
442 int ocf
= MBTOM(how
);
446 m
= objcache_get(mbuf_cache
, ocf
);
449 if ((how
& MB_TRYWAIT
) && ntries
++ == 0) {
450 struct objcache
*reclaimlist
[] = {
452 mbufcluster_cache
, mbufphdrcluster_cache
454 const int nreclaims
= __arysize(reclaimlist
);
456 if (!objcache_reclaimlist(reclaimlist
, nreclaims
, ocf
))
463 updatestats(m
, type
);
468 m_gethdr(int how
, int type
)
471 int ocf
= MBTOM(how
);
476 m
= objcache_get(mbufphdr_cache
, ocf
);
479 if ((how
& MB_TRYWAIT
) && ntries
++ == 0) {
480 struct objcache
*reclaimlist
[] = {
482 mbufcluster_cache
, mbufphdrcluster_cache
484 const int nreclaims
= __arysize(reclaimlist
);
486 if (!objcache_reclaimlist(reclaimlist
, nreclaims
, ocf
))
493 updatestats(m
, type
);
498 * Get a mbuf (not a mbuf cluster!) and zero it.
502 m_getclr(int how
, int type
)
506 m
= m_get(how
, type
);
508 bzero(m
->m_data
, MLEN
);
513 * Returns an mbuf with an attached cluster.
514 * Because many network drivers use this kind of buffers a lot, it is
515 * convenient to keep a small pool of free buffers of this kind.
516 * Even a small size such as 10 gives about 10% improvement in the
517 * forwarding rate in a bridge or router.
520 m_getcl(int how
, short type
, int flags
)
523 int ocflags
= MBTOM(how
);
528 if (flags
& M_PKTHDR
)
529 m
= objcache_get(mbufphdrcluster_cache
, ocflags
);
531 m
= objcache_get(mbufcluster_cache
, ocflags
);
534 if ((how
& MB_TRYWAIT
) && ntries
++ == 0) {
535 struct objcache
*reclaimlist
[1];
537 if (flags
& M_PKTHDR
)
538 reclaimlist
[0] = mbufcluster_cache
;
540 reclaimlist
[0] = mbufphdrcluster_cache
;
541 if (!objcache_reclaimlist(reclaimlist
, 1, ocflags
))
558 * Allocate chain of requested length.
561 m_getc(int len
, int how
, int type
)
563 struct mbuf
*n
, *nfirst
= NULL
, **ntail
= &nfirst
;
567 n
= m_getl(len
, how
, type
, 0, &nsize
);
583 * Allocate len-worth of mbufs and/or mbuf clusters (whatever fits best)
584 * and return a pointer to the head of the allocated chain. If m0 is
585 * non-null, then we assume that it is a single mbuf or an mbuf chain to
586 * which we want len bytes worth of mbufs and/or clusters attached, and so
587 * if we succeed in allocating it, we will just return a pointer to m0.
589 * If we happen to fail at any point during the allocation, we will free
590 * up everything we have already allocated and return NULL.
592 * Deprecated. Use m_getc() and m_cat() instead.
595 m_getm(struct mbuf
*m0
, int len
, int type
, int how
)
599 nfirst
= m_getc(len
, how
, type
);
602 m_last(m0
)->m_next
= nfirst
;
610 * Adds a cluster to a normal mbuf, M_EXT is set on success.
611 * Deprecated. Use m_getcl() instead.
614 m_mclget(struct mbuf
*m
, int how
)
616 struct mbcluster
*mcl
;
618 KKASSERT((m
->m_flags
& M_EXT
) == 0);
619 mcl
= objcache_get(mclmeta_cache
, MBTOM(how
));
624 /* leave the m_mbufs count intact for original mbuf */
630 * Updates to mbcluster must be MPSAFE. Only an entity which already has
631 * a reference to the cluster can ref it, so we are in no danger of
632 * racing an add with a subtract. But the operation must still be atomic
633 * since multiple entities may have a reference on the cluster.
635 * m_mclfree() is almost the same but it must contend with two entities
636 * freeing the cluster at the same time. If there is only one reference
637 * count we are the only entity referencing the cluster and no further
638 * locking is required. Otherwise we must protect against a race to 0
639 * with the serializer.
644 struct mbcluster
*mcl
= arg
;
646 atomic_add_int(&mcl
->mcl_refs
, 1);
652 struct mbcluster
*mcl
= arg
;
654 if (mcl
->mcl_refs
== 1) {
656 objcache_put(mclmeta_cache
, mcl
);
658 lwkt_serialize_enter(&mcl
->mcl_serializer
);
659 if (mcl
->mcl_refs
> 1) {
660 atomic_subtract_int(&mcl
->mcl_refs
, 1);
661 lwkt_serialize_exit(&mcl
->mcl_serializer
);
663 lwkt_serialize_exit(&mcl
->mcl_serializer
);
664 KKASSERT(mcl
->mcl_refs
== 1);
666 objcache_put(mclmeta_cache
, mcl
);
671 extern void db_print_backtrace(void);
674 * Free a single mbuf and any associated external storage. The successor,
675 * if any, is returned.
677 * We do need to check non-first mbuf for m_aux, since some of existing
678 * code does not call M_PREPEND properly.
679 * (example: call to bpf_mtap from drivers)
682 m_free(struct mbuf
*m
)
686 KASSERT(m
->m_type
!= MT_FREE
, ("freeing free mbuf %p", m
));
687 --mbtypes
[m
->m_type
];
692 * Make sure the mbuf is in constructed state before returning it
697 KKASSERT(m
->m_nextpkt
== NULL
);
699 if (m
->m_nextpkt
!= NULL
) {
701 static int afewtimes
= 10;
703 if (afewtimes
-- > 0) {
704 kprintf("mfree: m->m_nextpkt != NULL\n");
705 db_print_backtrace();
711 if (m
->m_flags
& M_PKTHDR
) {
712 m_tag_delete_chain(m
); /* eliminate XXX JH */
715 m
->m_flags
&= (M_EXT
| M_EXT_CLUSTER
| M_CLCACHE
| M_PHCACHE
);
718 * Clean the M_PKTHDR state so we can return the mbuf to its original
719 * cache. This is based on the PHCACHE flag which tells us whether
720 * the mbuf was originally allocated out of a packet-header cache
721 * or a non-packet-header cache.
723 if (m
->m_flags
& M_PHCACHE
) {
724 m
->m_flags
|= M_PKTHDR
;
725 m
->m_pkthdr
.rcvif
= NULL
; /* eliminate XXX JH */
726 m
->m_pkthdr
.csum_flags
= 0; /* eliminate XXX JH */
727 m
->m_pkthdr
.fw_flags
= 0; /* eliminate XXX JH */
728 SLIST_INIT(&m
->m_pkthdr
.tags
);
732 * Handle remaining flags combinations. M_CLCACHE tells us whether
733 * the mbuf was originally allocated from a cluster cache or not,
734 * and is totally separate from whether the mbuf is currently
735 * associated with a cluster.
738 switch(m
->m_flags
& (M_CLCACHE
| M_EXT
| M_EXT_CLUSTER
)) {
739 case M_CLCACHE
| M_EXT
| M_EXT_CLUSTER
:
741 * mbuf+cluster cache case. The mbuf was allocated from the
742 * combined mbuf_cluster cache and can be returned to the
743 * cache if the cluster hasn't been shared.
745 if (m_sharecount(m
) == 1) {
747 * The cluster has not been shared, we can just
748 * reset the data pointer and return the mbuf
749 * to the cluster cache. Note that the reference
750 * count is left intact (it is still associated with
753 m
->m_data
= m
->m_ext
.ext_buf
;
754 if (m
->m_flags
& M_PHCACHE
)
755 objcache_put(mbufphdrcluster_cache
, m
);
757 objcache_put(mbufcluster_cache
, m
);
761 * Hell. Someone else has a ref on this cluster,
762 * we have to disconnect it which means we can't
763 * put it back into the mbufcluster_cache, we
764 * have to destroy the mbuf.
766 * Other mbuf references to the cluster will typically
767 * be M_EXT | M_EXT_CLUSTER but without M_CLCACHE.
769 * XXX we could try to connect another cluster to
772 m
->m_ext
.ext_free(m
->m_ext
.ext_arg
);
773 m
->m_flags
&= ~(M_EXT
| M_EXT_CLUSTER
);
774 if (m
->m_flags
& M_PHCACHE
)
775 objcache_dtor(mbufphdrcluster_cache
, m
);
777 objcache_dtor(mbufcluster_cache
, m
);
780 case M_EXT
| M_EXT_CLUSTER
:
782 * Normal cluster associated with an mbuf that was allocated
783 * from the normal mbuf pool rather then the cluster pool.
784 * The cluster has to be independantly disassociated from the
787 if (m_sharecount(m
) == 1)
792 * Normal cluster association case, disconnect the cluster from
793 * the mbuf. The cluster may or may not be custom.
795 m
->m_ext
.ext_free(m
->m_ext
.ext_arg
);
796 m
->m_flags
&= ~(M_EXT
| M_EXT_CLUSTER
);
800 * return the mbuf to the mbuf cache.
802 if (m
->m_flags
& M_PHCACHE
) {
803 m
->m_data
= m
->m_pktdat
;
804 objcache_put(mbufphdr_cache
, m
);
806 m
->m_data
= m
->m_dat
;
807 objcache_put(mbuf_cache
, m
);
813 panic("bad mbuf flags %p %08x\n", m
, m
->m_flags
);
821 m_freem(struct mbuf
*m
)
830 * mbuf utility routines
834 * Lesser-used path for M_PREPEND: allocate new mbuf to prepend to chain and
838 m_prepend(struct mbuf
*m
, int len
, int how
)
842 if (m
->m_flags
& M_PKTHDR
)
843 mn
= m_gethdr(how
, m
->m_type
);
845 mn
= m_get(how
, m
->m_type
);
850 if (m
->m_flags
& M_PKTHDR
)
851 M_MOVE_PKTHDR(mn
, m
);
861 * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
862 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf.
863 * The wait parameter is a choice of MB_WAIT/MB_DONTWAIT from caller.
864 * Note that the copy is read-only, because clusters are not copied,
865 * only their reference counts are incremented.
868 m_copym(const struct mbuf
*m
, int off0
, int len
, int wait
)
870 struct mbuf
*n
, **np
;
875 KASSERT(off
>= 0, ("m_copym, negative off %d", off
));
876 KASSERT(len
>= 0, ("m_copym, negative len %d", len
));
877 if (off
== 0 && m
->m_flags
& M_PKTHDR
)
880 KASSERT(m
!= NULL
, ("m_copym, offset > size of mbuf chain"));
890 KASSERT(len
== M_COPYALL
,
891 ("m_copym, length > size of mbuf chain"));
895 * Because we are sharing any cluster attachment below,
896 * be sure to get an mbuf that does not have a cluster
897 * associated with it.
900 n
= m_gethdr(wait
, m
->m_type
);
902 n
= m_get(wait
, m
->m_type
);
907 if (!m_dup_pkthdr(n
, m
, wait
))
909 if (len
== M_COPYALL
)
910 n
->m_pkthdr
.len
-= off0
;
912 n
->m_pkthdr
.len
= len
;
915 n
->m_len
= min(len
, m
->m_len
- off
);
916 if (m
->m_flags
& M_EXT
) {
917 KKASSERT((n
->m_flags
& M_EXT
) == 0);
918 n
->m_data
= m
->m_data
+ off
;
919 m
->m_ext
.ext_ref(m
->m_ext
.ext_arg
);
921 n
->m_flags
|= m
->m_flags
& (M_EXT
| M_EXT_CLUSTER
);
923 bcopy(mtod(m
, caddr_t
)+off
, mtod(n
, caddr_t
),
926 if (len
!= M_COPYALL
)
942 * Copy an entire packet, including header (which must be present).
943 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
944 * Note that the copy is read-only, because clusters are not copied,
945 * only their reference counts are incremented.
946 * Preserve alignment of the first mbuf so if the creator has left
947 * some room at the beginning (e.g. for inserting protocol headers)
948 * the copies also have the room available.
951 m_copypacket(struct mbuf
*m
, int how
)
953 struct mbuf
*top
, *n
, *o
;
955 n
= m_gethdr(how
, m
->m_type
);
960 if (!m_dup_pkthdr(n
, m
, how
))
963 if (m
->m_flags
& M_EXT
) {
964 KKASSERT((n
->m_flags
& M_EXT
) == 0);
965 n
->m_data
= m
->m_data
;
966 m
->m_ext
.ext_ref(m
->m_ext
.ext_arg
);
968 n
->m_flags
|= m
->m_flags
& (M_EXT
| M_EXT_CLUSTER
);
970 n
->m_data
= n
->m_pktdat
+ (m
->m_data
- m
->m_pktdat
);
971 bcopy(mtod(m
, char *), mtod(n
, char *), n
->m_len
);
976 o
= m_get(how
, m
->m_type
);
984 if (m
->m_flags
& M_EXT
) {
985 KKASSERT((n
->m_flags
& M_EXT
) == 0);
986 n
->m_data
= m
->m_data
;
987 m
->m_ext
.ext_ref(m
->m_ext
.ext_arg
);
989 n
->m_flags
|= m
->m_flags
& (M_EXT
| M_EXT_CLUSTER
);
991 bcopy(mtod(m
, char *), mtod(n
, char *), n
->m_len
);
1004 * Copy data from an mbuf chain starting "off" bytes from the beginning,
1005 * continuing for "len" bytes, into the indicated buffer.
1008 m_copydata(const struct mbuf
*m
, int off
, int len
, caddr_t cp
)
1012 KASSERT(off
>= 0, ("m_copydata, negative off %d", off
));
1013 KASSERT(len
>= 0, ("m_copydata, negative len %d", len
));
1015 KASSERT(m
!= NULL
, ("m_copydata, offset > size of mbuf chain"));
1022 KASSERT(m
!= NULL
, ("m_copydata, length > size of mbuf chain"));
1023 count
= min(m
->m_len
- off
, len
);
1024 bcopy(mtod(m
, caddr_t
) + off
, cp
, count
);
1033 * Copy a packet header mbuf chain into a completely new chain, including
1034 * copying any mbuf clusters. Use this instead of m_copypacket() when
1035 * you need a writable copy of an mbuf chain.
1038 m_dup(struct mbuf
*m
, int how
)
1040 struct mbuf
**p
, *top
= NULL
;
1041 int remain
, moff
, nsize
;
1046 KASSERT((m
->m_flags
& M_PKTHDR
) != 0, ("%s: !PKTHDR", __func__
));
1048 /* While there's more data, get a new mbuf, tack it on, and fill it */
1049 remain
= m
->m_pkthdr
.len
;
1052 while (remain
> 0 || top
== NULL
) { /* allow m->m_pkthdr.len == 0 */
1055 /* Get the next new mbuf */
1056 n
= m_getl(remain
, how
, m
->m_type
, top
== NULL
? M_PKTHDR
: 0,
1061 if (!m_dup_pkthdr(n
, m
, how
))
1064 /* Link it into the new chain */
1068 /* Copy data from original mbuf(s) into new mbuf */
1070 while (n
->m_len
< nsize
&& m
!= NULL
) {
1071 int chunk
= min(nsize
- n
->m_len
, m
->m_len
- moff
);
1073 bcopy(m
->m_data
+ moff
, n
->m_data
+ n
->m_len
, chunk
);
1077 if (moff
== m
->m_len
) {
1083 /* Check correct total mbuf length */
1084 KASSERT((remain
> 0 && m
!= NULL
) || (remain
== 0 && m
== NULL
),
1085 ("%s: bogus m_pkthdr.len", __func__
));
1097 * Concatenate mbuf chain n to m.
1098 * Both chains must be of the same type (e.g. MT_DATA).
1099 * Any m_pkthdr is not updated.
1102 m_cat(struct mbuf
*m
, struct mbuf
*n
)
1106 if (m
->m_flags
& M_EXT
||
1107 m
->m_data
+ m
->m_len
+ n
->m_len
>= &m
->m_dat
[MLEN
]) {
1108 /* just join the two chains */
1112 /* splat the data from one into the other */
1113 bcopy(mtod(n
, caddr_t
), mtod(m
, caddr_t
) + m
->m_len
,
1115 m
->m_len
+= n
->m_len
;
1121 m_adj(struct mbuf
*mp
, int req_len
)
1127 if ((m
= mp
) == NULL
)
1133 while (m
!= NULL
&& len
> 0) {
1134 if (m
->m_len
<= len
) {
1145 if (mp
->m_flags
& M_PKTHDR
)
1146 m
->m_pkthdr
.len
-= (req_len
- len
);
1149 * Trim from tail. Scan the mbuf chain,
1150 * calculating its length and finding the last mbuf.
1151 * If the adjustment only affects this mbuf, then just
1152 * adjust and return. Otherwise, rescan and truncate
1153 * after the remaining size.
1159 if (m
->m_next
== (struct mbuf
*)0)
1163 if (m
->m_len
>= len
) {
1165 if (mp
->m_flags
& M_PKTHDR
)
1166 mp
->m_pkthdr
.len
-= len
;
1173 * Correct length for chain is "count".
1174 * Find the mbuf with last data, adjust its length,
1175 * and toss data from remaining mbufs on chain.
1178 if (m
->m_flags
& M_PKTHDR
)
1179 m
->m_pkthdr
.len
= count
;
1180 for (; m
; m
= m
->m_next
) {
1181 if (m
->m_len
>= count
) {
1188 (m
= m
->m_next
) ->m_len
= 0;
1193 * Rearrange an mbuf chain so that len bytes are contiguous
1194 * and in the data area of an mbuf (so that mtod will work for a structure
1195 * of size len). Returns the resulting mbuf chain on success, frees it and
1196 * returns null on failure. If there is room, it will add up to
1197 * max_protohdr-len extra bytes to the contiguous region in an attempt to
1198 * avoid being called next time.
1201 m_pullup(struct mbuf
*n
, int len
)
1208 * If first mbuf has no cluster, and has room for len bytes
1209 * without shifting current data, pullup into it,
1210 * otherwise allocate a new mbuf to prepend to the chain.
1212 if (!(n
->m_flags
& M_EXT
) &&
1213 n
->m_data
+ len
< &n
->m_dat
[MLEN
] &&
1215 if (n
->m_len
>= len
)
1223 if (n
->m_flags
& M_PKTHDR
)
1224 m
= m_gethdr(MB_DONTWAIT
, n
->m_type
);
1226 m
= m_get(MB_DONTWAIT
, n
->m_type
);
1230 if (n
->m_flags
& M_PKTHDR
)
1231 M_MOVE_PKTHDR(m
, n
);
1233 space
= &m
->m_dat
[MLEN
] - (m
->m_data
+ m
->m_len
);
1235 count
= min(min(max(len
, max_protohdr
), space
), n
->m_len
);
1236 bcopy(mtod(n
, caddr_t
), mtod(m
, caddr_t
) + m
->m_len
,
1246 } while (len
> 0 && n
);
1260 * Partition an mbuf chain in two pieces, returning the tail --
1261 * all but the first len0 bytes. In case of failure, it returns NULL and
1262 * attempts to restore the chain to its original state.
1264 * Note that the resulting mbufs might be read-only, because the new
1265 * mbuf can end up sharing an mbuf cluster with the original mbuf if
1266 * the "breaking point" happens to lie within a cluster mbuf. Use the
1267 * M_WRITABLE() macro to check for this case.
1270 m_split(struct mbuf
*m0
, int len0
, int wait
)
1273 unsigned len
= len0
, remain
;
1275 for (m
= m0
; m
&& len
> m
->m_len
; m
= m
->m_next
)
1279 remain
= m
->m_len
- len
;
1280 if (m0
->m_flags
& M_PKTHDR
) {
1281 n
= m_gethdr(wait
, m0
->m_type
);
1284 n
->m_pkthdr
.rcvif
= m0
->m_pkthdr
.rcvif
;
1285 n
->m_pkthdr
.len
= m0
->m_pkthdr
.len
- len0
;
1286 m0
->m_pkthdr
.len
= len0
;
1287 if (m
->m_flags
& M_EXT
)
1289 if (remain
> MHLEN
) {
1290 /* m can't be the lead packet */
1292 n
->m_next
= m_split(m
, len
, wait
);
1293 if (n
->m_next
== NULL
) {
1301 MH_ALIGN(n
, remain
);
1302 } else if (remain
== 0) {
1307 n
= m_get(wait
, m
->m_type
);
1313 if (m
->m_flags
& M_EXT
) {
1314 KKASSERT((n
->m_flags
& M_EXT
) == 0);
1315 n
->m_data
= m
->m_data
+ len
;
1316 m
->m_ext
.ext_ref(m
->m_ext
.ext_arg
);
1317 n
->m_ext
= m
->m_ext
;
1318 n
->m_flags
|= m
->m_flags
& (M_EXT
| M_EXT_CLUSTER
);
1320 bcopy(mtod(m
, caddr_t
) + len
, mtod(n
, caddr_t
), remain
);
1324 n
->m_next
= m
->m_next
;
1330 * Routine to copy from device local memory into mbufs.
1331 * Note: "offset" is ill-defined and always called as 0, so ignore it.
1334 m_devget(char *buf
, int len
, int offset
, struct ifnet
*ifp
,
1335 void (*copy
)(volatile const void *from
, volatile void *to
, size_t length
))
1337 struct mbuf
*m
, *mfirst
= NULL
, **mtail
;
1346 m
= m_getl(len
, MB_DONTWAIT
, MT_DATA
, flags
, &nsize
);
1351 m
->m_len
= min(len
, nsize
);
1353 if (flags
& M_PKTHDR
) {
1354 if (len
+ max_linkhdr
<= nsize
)
1355 m
->m_data
+= max_linkhdr
;
1356 m
->m_pkthdr
.rcvif
= ifp
;
1357 m
->m_pkthdr
.len
= len
;
1361 copy(buf
, m
->m_data
, (unsigned)m
->m_len
);
1372 * Copy data from a buffer back into the indicated mbuf chain,
1373 * starting "off" bytes from the beginning, extending the mbuf
1374 * chain if necessary.
1377 m_copyback(struct mbuf
*m0
, int off
, int len
, caddr_t cp
)
1380 struct mbuf
*m
= m0
, *n
;
1385 while (off
> (mlen
= m
->m_len
)) {
1388 if (m
->m_next
== NULL
) {
1389 n
= m_getclr(MB_DONTWAIT
, m
->m_type
);
1392 n
->m_len
= min(MLEN
, len
+ off
);
1398 mlen
= min (m
->m_len
- off
, len
);
1399 bcopy(cp
, off
+ mtod(m
, caddr_t
), (unsigned)mlen
);
1407 if (m
->m_next
== NULL
) {
1408 n
= m_get(MB_DONTWAIT
, m
->m_type
);
1411 n
->m_len
= min(MLEN
, len
);
1416 out
: if (((m
= m0
)->m_flags
& M_PKTHDR
) && (m
->m_pkthdr
.len
< totlen
))
1417 m
->m_pkthdr
.len
= totlen
;
1421 m_print(const struct mbuf
*m
)
1424 const struct mbuf
*m2
;
1426 len
= m
->m_pkthdr
.len
;
1429 kprintf("%p %*D\n", m2
, m2
->m_len
, (u_char
*)m2
->m_data
, "-");
1437 * "Move" mbuf pkthdr from "from" to "to".
1438 * "from" must have M_PKTHDR set, and "to" must be empty.
1441 m_move_pkthdr(struct mbuf
*to
, struct mbuf
*from
)
1443 KASSERT((to
->m_flags
& M_PKTHDR
), ("m_move_pkthdr: not packet header"));
1445 to
->m_flags
|= from
->m_flags
& M_COPYFLAGS
;
1446 to
->m_pkthdr
= from
->m_pkthdr
; /* especially tags */
1447 SLIST_INIT(&from
->m_pkthdr
.tags
); /* purge tags from src */
1451 * Duplicate "from"'s mbuf pkthdr in "to".
1452 * "from" must have M_PKTHDR set, and "to" must be empty.
1453 * In particular, this does a deep copy of the packet tags.
1456 m_dup_pkthdr(struct mbuf
*to
, const struct mbuf
*from
, int how
)
1458 KASSERT((to
->m_flags
& M_PKTHDR
), ("m_dup_pkthdr: not packet header"));
1460 to
->m_flags
= (from
->m_flags
& M_COPYFLAGS
) |
1461 (to
->m_flags
& ~M_COPYFLAGS
);
1462 to
->m_pkthdr
= from
->m_pkthdr
;
1463 SLIST_INIT(&to
->m_pkthdr
.tags
);
1464 return (m_tag_copy_chain(to
, from
, how
));
1468 * Defragment a mbuf chain, returning the shortest possible
1469 * chain of mbufs and clusters. If allocation fails and
1470 * this cannot be completed, NULL will be returned, but
1471 * the passed in chain will be unchanged. Upon success,
1472 * the original chain will be freed, and the new chain
1475 * If a non-packet header is passed in, the original
1476 * mbuf (chain?) will be returned unharmed.
1478 * m_defrag_nofree doesn't free the passed in mbuf.
1481 m_defrag(struct mbuf
*m0
, int how
)
1485 if ((m_new
= m_defrag_nofree(m0
, how
)) == NULL
)
1493 m_defrag_nofree(struct mbuf
*m0
, int how
)
1495 struct mbuf
*m_new
= NULL
, *m_final
= NULL
;
1496 int progress
= 0, length
, nsize
;
1498 if (!(m0
->m_flags
& M_PKTHDR
))
1501 #ifdef MBUF_STRESS_TEST
1502 if (m_defragrandomfailures
) {
1503 int temp
= karc4random() & 0xff;
1509 m_final
= m_getl(m0
->m_pkthdr
.len
, how
, MT_DATA
, M_PKTHDR
, &nsize
);
1510 if (m_final
== NULL
)
1512 m_final
->m_len
= 0; /* in case m0->m_pkthdr.len is zero */
1514 if (m_dup_pkthdr(m_final
, m0
, how
) == NULL
)
1519 while (progress
< m0
->m_pkthdr
.len
) {
1520 length
= m0
->m_pkthdr
.len
- progress
;
1521 if (length
> MCLBYTES
)
1524 if (m_new
== NULL
) {
1525 m_new
= m_getl(length
, how
, MT_DATA
, 0, &nsize
);
1530 m_copydata(m0
, progress
, length
, mtod(m_new
, caddr_t
));
1532 m_new
->m_len
= length
;
1533 if (m_new
!= m_final
)
1534 m_cat(m_final
, m_new
);
1537 if (m0
->m_next
== NULL
)
1540 m_defragbytes
+= m_final
->m_pkthdr
.len
;
1551 * Move data from uio into mbufs.
1554 m_uiomove(struct uio
*uio
)
1556 struct mbuf
*m
; /* current working mbuf */
1557 struct mbuf
*head
= NULL
; /* result mbuf chain */
1558 struct mbuf
**mp
= &head
;
1559 int resid
= uio
->uio_resid
, nsize
, flags
= M_PKTHDR
, error
;
1562 m
= m_getl(resid
, MB_WAIT
, MT_DATA
, flags
, &nsize
);
1564 m
->m_pkthdr
.len
= 0;
1565 /* Leave room for protocol headers. */
1570 m
->m_len
= min(nsize
, resid
);
1571 error
= uiomove(mtod(m
, caddr_t
), m
->m_len
, uio
);
1578 head
->m_pkthdr
.len
+= m
->m_len
;
1580 } while (resid
> 0);
1590 m_last(struct mbuf
*m
)
1598 * Return the number of bytes in an mbuf chain.
1599 * If lastm is not NULL, also return the last mbuf.
1602 m_lengthm(struct mbuf
*m
, struct mbuf
**lastm
)
1605 struct mbuf
*prev
= m
;
1618 * Like m_lengthm(), except also keep track of mbuf usage.
1621 m_countm(struct mbuf
*m
, struct mbuf
**lastm
, u_int
*pmbcnt
)
1623 u_int len
= 0, mbcnt
= 0;
1624 struct mbuf
*prev
= m
;
1629 if (m
->m_flags
& M_EXT
)
1630 mbcnt
+= m
->m_ext
.ext_size
;