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;
27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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) 2004 Jeffrey M. Hsu. All rights reserved.
37 * License terms: all terms for the DragonFly license above plus the following:
39 * 4. All advertising materials mentioning features or use of this software
40 * must display the following acknowledgement:
42 * This product includes software developed by Jeffrey M. Hsu
43 * for the DragonFly Project.
45 * This requirement may be waived with permission from Jeffrey Hsu.
46 * This requirement will sunset and may be removed on July 8 2005,
47 * after which the standard DragonFly license (as shown above) will
52 * Copyright (c) 1982, 1986, 1988, 1991, 1993
53 * The Regents of the University of California. All rights reserved.
55 * Redistribution and use in source and binary forms, with or without
56 * modification, are permitted provided that the following conditions
58 * 1. Redistributions of source code must retain the above copyright
59 * notice, this list of conditions and the following disclaimer.
60 * 2. Redistributions in binary form must reproduce the above copyright
61 * notice, this list of conditions and the following disclaimer in the
62 * documentation and/or other materials provided with the distribution.
63 * 3. All advertising materials mentioning features or use of this software
64 * must display the following acknowledgement:
65 * This product includes software developed by the University of
66 * California, Berkeley and its contributors.
67 * 4. Neither the name of the University nor the names of its contributors
68 * may be used to endorse or promote products derived from this software
69 * without specific prior written permission.
71 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
72 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
73 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
74 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
75 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
76 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
77 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
78 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
79 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
80 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
83 * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94
84 * $FreeBSD: src/sys/kern/uipc_mbuf.c,v 1.51.2.24 2003/04/15 06:59:29 silby Exp $
85 * $DragonFly: src/sys/kern/uipc_mbuf.c,v 1.48 2005/06/09 01:55:12 hsu Exp $
88 #include "opt_param.h"
90 #include "opt_mbuf_stress_test.h"
91 #include <sys/param.h>
92 #include <sys/systm.h>
93 #include <sys/malloc.h>
95 #include <sys/kernel.h>
96 #include <sys/sysctl.h>
97 #include <sys/domain.h>
98 #include <sys/objcache.h>
99 #include <sys/protosw.h>
101 #include <sys/thread.h>
102 #include <sys/globaldata.h>
103 #include <sys/thread2.h>
106 #include <vm/vm_kern.h>
107 #include <vm/vm_extern.h>
110 #include <machine/cpu.h>
114 * mbuf cluster meta-data
121 static void mbinit(void *);
122 SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL)
124 static u_long mbtypes[MT_NTYPES];
126 struct mbstat mbstat;
135 #ifdef MBUF_STRESS_TEST
136 int m_defragrandomfailures;
139 struct objcache *mbuf_cache, *mbufphdr_cache;
140 struct objcache *mclmeta_cache;
141 struct objcache *mbufcluster_cache, *mbufphdrcluster_cache;
146 SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW,
147 &max_linkhdr, 0, "");
148 SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW,
149 &max_protohdr, 0, "");
150 SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0, "");
151 SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW,
152 &max_datalen, 0, "");
153 SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_wait, CTLFLAG_RW,
155 SYSCTL_STRUCT(_kern_ipc, KIPC_MBSTAT, mbstat, CTLFLAG_RW, &mbstat, mbstat, "");
156 SYSCTL_OPAQUE(_kern_ipc, OID_AUTO, mbtypes, CTLFLAG_RD, mbtypes,
157 sizeof(mbtypes), "LU", "");
158 SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters, CTLFLAG_RW,
159 &nmbclusters, 0, "Maximum number of mbuf clusters available");
160 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbufs, CTLFLAG_RW, &nmbufs, 0,
161 "Maximum number of mbufs available");
163 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD,
164 &m_defragpackets, 0, "");
165 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD,
166 &m_defragbytes, 0, "");
167 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD,
168 &m_defraguseless, 0, "");
169 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD,
170 &m_defragfailure, 0, "");
171 #ifdef MBUF_STRESS_TEST
172 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW,
173 &m_defragrandomfailures, 0, "");
176 static MALLOC_DEFINE(M_MBUF, "mbuf", "mbuf");
177 static MALLOC_DEFINE(M_MBUFCL, "mbufcl", "mbufcl");
178 static MALLOC_DEFINE(M_MCLMETA, "mclmeta", "mclmeta");
180 static void m_reclaim (void);
181 static void m_mclref(void *arg);
182 static void m_mclfree(void *arg);
185 #define NMBCLUSTERS (512 + maxusers * 16)
188 #define NMBUFS (nmbclusters * 2)
192 * Perform sanity checks of tunables declared above.
195 tunable_mbinit(void *dummy)
199 * This has to be done before VM init.
201 nmbclusters = NMBCLUSTERS;
202 TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
204 TUNABLE_INT_FETCH("kern.ipc.nmbufs", &nmbufs);
206 if (nmbufs < nmbclusters * 2)
207 nmbufs = nmbclusters * 2;
211 SYSINIT(tunable_mbinit, SI_SUB_TUNABLES, SI_ORDER_ANY, tunable_mbinit, NULL);
213 /* "number of clusters of pages" */
219 * The mbuf object cache only guarantees that m_next and m_nextpkt are
220 * NULL and that m_data points to the beginning of the data area. In
221 * particular, m_len and m_pkthdr.len are uninitialized. It is the
222 * responsibility of the caller to initialize those fields before use.
225 static boolean_t __inline
226 mbuf_ctor(void *obj, void *private, int ocflags)
228 struct mbuf *m = obj;
232 m->m_data = m->m_dat;
239 * Initialize the mbuf and the packet header fields.
242 mbufphdr_ctor(void *obj, void *private, int ocflags)
244 struct mbuf *m = obj;
248 m->m_data = m->m_pktdat;
249 m->m_flags = M_PKTHDR | M_PHCACHE;
251 m->m_pkthdr.rcvif = NULL; /* eliminate XXX JH */
252 SLIST_INIT(&m->m_pkthdr.tags);
253 m->m_pkthdr.csum_flags = 0; /* eliminate XXX JH */
254 m->m_pkthdr.fw_flags = 0; /* eliminate XXX JH */
260 * A mbcluster object consists of 2K (MCLBYTES) cluster and a refcount.
263 mclmeta_ctor(void *obj, void *private, int ocflags)
265 struct mbcluster *cl = obj;
268 if (ocflags & M_NOWAIT)
269 buf = malloc(MCLBYTES, M_MBUFCL, M_NOWAIT | M_ZERO);
271 buf = malloc(MCLBYTES, M_MBUFCL, M_INTWAIT | M_ZERO);
280 linkcluster(struct mbuf *m, struct mbcluster *cl)
283 * Add the cluster to the mbuf. The caller will detect that the
284 * mbuf now has an attached cluster.
286 m->m_ext.ext_arg = cl;
287 m->m_ext.ext_buf = cl->mcl_data;
288 m->m_ext.ext_ref = m_mclref;
289 m->m_ext.ext_free = m_mclfree;
290 m->m_ext.ext_size = MCLBYTES;
293 m->m_data = m->m_ext.ext_buf;
294 m->m_flags |= M_EXT | M_EXT_CLUSTER;
298 mbufphdrcluster_ctor(void *obj, void *private, int ocflags)
300 struct mbuf *m = obj;
301 struct mbcluster *cl;
303 mbufphdr_ctor(obj, private, ocflags);
304 cl = objcache_get(mclmeta_cache, ocflags);
307 m->m_flags |= M_CLCACHE;
313 mbufcluster_ctor(void *obj, void *private, int ocflags)
315 struct mbuf *m = obj;
316 struct mbcluster *cl;
318 mbuf_ctor(obj, private, ocflags);
319 cl = objcache_get(mclmeta_cache, ocflags);
322 m->m_flags |= M_CLCACHE;
328 mclmeta_dtor(void *obj, void *private)
330 struct mbcluster *mcl = obj;
332 KKASSERT(mcl->mcl_refs == 0);
333 free(mcl->mcl_data, M_MBUFCL);
337 * Used for both the cluster and cluster PHDR caches.
339 * The mbuf may have lost its cluster due to sharing, deal
340 * with the situation by checking M_EXT.
343 mbufcluster_dtor(void *obj, void *private)
345 struct mbuf *m = obj;
346 struct mbcluster *mcl;
348 if (m->m_flags & M_EXT) {
349 KKASSERT((m->m_flags & M_EXT_CLUSTER) != 0);
350 mcl = m->m_ext.ext_arg;
351 KKASSERT(mcl->mcl_refs == 1);
353 objcache_put(mclmeta_cache, mcl);
357 struct objcache_malloc_args mbuf_malloc_args = { MSIZE, M_MBUF };
358 struct objcache_malloc_args mclmeta_malloc_args =
359 { sizeof(struct mbcluster), M_MCLMETA };
365 mbstat.m_msize = MSIZE;
366 mbstat.m_mclbytes = MCLBYTES;
367 mbstat.m_minclsize = MINCLSIZE;
368 mbstat.m_mlen = MLEN;
369 mbstat.m_mhlen = MHLEN;
371 mbuf_cache = objcache_create("mbuf", nmbufs, 0,
372 mbuf_ctor, null_dtor, NULL,
373 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
374 mbufphdr_cache = objcache_create("mbuf pkt hdr", nmbufs, 64,
375 mbufphdr_ctor, null_dtor, NULL,
376 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
377 mclmeta_cache = objcache_create("cluster mbuf", nmbclusters , 0,
378 mclmeta_ctor, mclmeta_dtor, NULL,
379 objcache_malloc_alloc, objcache_malloc_free, &mclmeta_malloc_args);
380 mbufcluster_cache = objcache_create("mbuf + cluster", nmbclusters, 0,
381 mbufcluster_ctor, mbufcluster_dtor, NULL,
382 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
383 mbufphdrcluster_cache = objcache_create("mbuf pkt hdr + cluster",
384 nmbclusters, 64, mbufphdrcluster_ctor, mbufcluster_dtor, NULL,
385 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
390 * Return the number of references to this mbuf's data. 0 is returned
391 * if the mbuf is not M_EXT, a reference count is returned if it is
392 * M_EXT | M_EXT_CLUSTER, and 99 is returned if it is a special M_EXT.
395 m_sharecount(struct mbuf *m)
397 switch (m->m_flags & (M_EXT | M_EXT_CLUSTER)) {
402 case M_EXT | M_EXT_CLUSTER:
403 return (((struct mbcluster *)m->m_ext.ext_arg)->mcl_refs);
406 return (0); /* to shut up compiler */
410 * change mbuf to new type
413 m_chtype(struct mbuf *m, int type)
417 --mbtypes[m->m_type];
429 SLIST_FOREACH(dp, &domains, dom_next) {
430 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) {
440 updatestats(struct mbuf *m, int type)
454 m_get(int how, int type)
458 int ocf = MBTOM(how);
462 m = objcache_get(mbuf_cache, ocf);
465 if ((how & MB_TRYWAIT) && ntries++ == 0) {
466 struct objcache *reclaimlist[] = {
468 mbufcluster_cache, mbufphdrcluster_cache
470 const int nreclaims = __arysize(reclaimlist);
472 if (!objcache_reclaimlist(reclaimlist, nreclaims, ocf))
479 updatestats(m, type);
484 m_gethdr(int how, int type)
487 int ocf = MBTOM(how);
492 m = objcache_get(mbufphdr_cache, ocf);
495 if ((how & MB_TRYWAIT) && ntries++ == 0) {
496 struct objcache *reclaimlist[] = {
498 mbufcluster_cache, mbufphdrcluster_cache
500 const int nreclaims = __arysize(reclaimlist);
502 if (!objcache_reclaimlist(reclaimlist, nreclaims, ocf))
509 updatestats(m, type);
514 * Get a mbuf (not a mbuf cluster!) and zero it.
518 m_getclr(int how, int type)
522 m = m_get(how, type);
524 bzero(m->m_data, MLEN);
529 * Returns an mbuf with an attached cluster.
530 * Because many network drivers use this kind of buffers a lot, it is
531 * convenient to keep a small pool of free buffers of this kind.
532 * Even a small size such as 10 gives about 10% improvement in the
533 * forwarding rate in a bridge or router.
536 m_getcl(int how, short type, int flags)
539 int ocflags = MBTOM(how);
544 if (flags & M_PKTHDR)
545 m = objcache_get(mbufphdrcluster_cache, ocflags);
547 m = objcache_get(mbufcluster_cache, ocflags);
550 if ((how & MB_TRYWAIT) && ntries++ == 0) {
551 struct objcache *reclaimlist[1];
553 if (flags & M_PKTHDR)
554 reclaimlist[0] = mbufcluster_cache;
556 reclaimlist[0] = mbufphdrcluster_cache;
557 if (!objcache_reclaimlist(reclaimlist, 1, ocflags))
574 * Allocate chain of requested length.
577 m_getc(int len, int how, int type)
579 struct mbuf *n, *nfirst = NULL, **ntail = &nfirst;
583 n = m_getl(len, how, type, 0, &nsize);
599 * Allocate len-worth of mbufs and/or mbuf clusters (whatever fits best)
600 * and return a pointer to the head of the allocated chain. If m0 is
601 * non-null, then we assume that it is a single mbuf or an mbuf chain to
602 * which we want len bytes worth of mbufs and/or clusters attached, and so
603 * if we succeed in allocating it, we will just return a pointer to m0.
605 * If we happen to fail at any point during the allocation, we will free
606 * up everything we have already allocated and return NULL.
608 * Deprecated. Use m_getc() and m_cat() instead.
611 m_getm(struct mbuf *m0, int len, int how, int type)
615 nfirst = m_getc(len, how, type);
618 m_last(m0)->m_next = nfirst;
626 * Adds a cluster to a normal mbuf, M_EXT is set on success.
627 * Deprecated. Use m_getcl() instead.
630 m_mclget(struct mbuf *m, int how)
632 struct mbcluster *mcl;
634 KKASSERT((m->m_flags & M_EXT) == 0);
635 mcl = objcache_get(mclmeta_cache, MBTOM(how));
649 struct mbcluster *mcl = arg;
651 atomic_add_int(&mcl->mcl_refs, 1);
657 struct mbcluster *mcl = arg;
659 /* XXX interrupt race. Currently called from a critical section */
660 if (mcl->mcl_refs > 1) {
661 atomic_subtract_int(&mcl->mcl_refs, 1);
663 KKASSERT(mcl->mcl_refs == 1);
665 objcache_put(mclmeta_cache, mcl);
669 extern void db_print_backtrace(void);
672 * Free a single mbuf and any associated external storage. The successor,
673 * if any, is returned.
675 * We do need to check non-first mbuf for m_aux, since some of existing
676 * code does not call M_PREPEND properly.
677 * (example: call to bpf_mtap from drivers)
680 m_free(struct mbuf *m)
684 KASSERT(m->m_type != MT_FREE, ("freeing free mbuf %p", m));
685 --mbtypes[m->m_type];
690 * Make sure the mbuf is in constructed state before returning it
695 KKASSERT(m->m_nextpkt == NULL);
697 if (m->m_nextpkt != NULL) {
699 static int afewtimes = 10;
701 if (afewtimes-- > 0) {
702 printf("mfree: m->m_nextpkt != NULL\n");
703 db_print_backtrace();
709 if (m->m_flags & M_PKTHDR) {
710 m_tag_delete_chain(m); /* eliminate XXX JH */
713 m->m_flags &= (M_EXT | M_EXT_CLUSTER | M_CLCACHE | M_PHCACHE);
716 * Clean the M_PKTHDR state so we can return the mbuf to its original
717 * cache. This is based on the PHCACHE flag which tells us whether
718 * the mbuf was originally allocated out of a packet-header cache
719 * or a non-packet-header cache.
721 if (m->m_flags & M_PHCACHE) {
722 m->m_flags |= M_PKTHDR;
723 m->m_pkthdr.rcvif = NULL; /* eliminate XXX JH */
724 m->m_pkthdr.csum_flags = 0; /* eliminate XXX JH */
725 m->m_pkthdr.fw_flags = 0; /* eliminate XXX JH */
729 * Handle remaining flags combinations. M_CLCACHE tells us whether
730 * the mbuf was originally allocated from a cluster cache or not,
731 * and is totally separate from whether the mbuf is currently
732 * associated with a cluster.
735 switch(m->m_flags & (M_CLCACHE | M_EXT | M_EXT_CLUSTER)) {
736 case M_CLCACHE | M_EXT | M_EXT_CLUSTER:
738 * mbuf+cluster cache case. The mbuf was allocated from the
739 * combined mbuf_cluster cache and can be returned to the
740 * cache if the cluster hasn't been shared.
742 if (m_sharecount(m) == 1) {
744 * The cluster has not been shared, we can just
745 * reset the data pointer and return the mbuf
746 * to the cluster cache. Note that the reference
747 * count is left intact (it is still associated with
750 m->m_data = m->m_ext.ext_buf;
751 if (m->m_flags & M_PHCACHE)
752 objcache_put(mbufphdrcluster_cache, m);
754 objcache_put(mbufcluster_cache, m);
757 * Hell. Someone else has a ref on this cluster,
758 * we have to disconnect it which means we can't
759 * put it back into the mbufcluster_cache, we
760 * have to destroy the mbuf.
762 * XXX we could try to connect another cluster to
765 m->m_ext.ext_free(m->m_ext.ext_arg);
766 m->m_flags &= ~(M_EXT | M_EXT_CLUSTER);
767 if (m->m_flags & M_PHCACHE)
768 objcache_dtor(mbufphdrcluster_cache, m);
770 objcache_dtor(mbufcluster_cache, m);
774 case M_EXT | M_EXT_CLUSTER:
776 * Normal cluster associated with an mbuf that was allocated
777 * from the normal mbuf pool rather then the cluster pool.
778 * The cluster has to be independantly disassociated from the
785 * Normal cluster association case, disconnect the cluster from
786 * the mbuf. The cluster may or may not be custom.
788 m->m_ext.ext_free(m->m_ext.ext_arg);
789 m->m_flags &= ~(M_EXT | M_EXT_CLUSTER);
793 * return the mbuf to the mbuf cache.
795 if (m->m_flags & M_PHCACHE) {
796 m->m_data = m->m_pktdat;
797 objcache_put(mbufphdr_cache, m);
799 m->m_data = m->m_dat;
800 objcache_put(mbuf_cache, m);
806 panic("bad mbuf flags %p %08x\n", m, m->m_flags);
814 m_freem(struct mbuf *m)
823 * mbuf utility routines
827 * Lesser-used path for M_PREPEND: allocate new mbuf to prepend to chain and
831 m_prepend(struct mbuf *m, int len, int how)
835 mn = m_getl(MLEN, how, m->m_type, m->m_flags & M_PKTHDR, NULL);
840 if (m->m_flags & M_PKTHDR)
841 M_MOVE_PKTHDR(mn, m);
851 * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
852 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf.
853 * The wait parameter is a choice of MB_WAIT/MB_DONTWAIT from caller.
854 * Note that the copy is read-only, because clusters are not copied,
855 * only their reference counts are incremented.
858 m_copym(const struct mbuf *m, int off0, int len, int wait)
860 struct mbuf *n, **np;
865 KASSERT(off >= 0, ("m_copym, negative off %d", off));
866 KASSERT(len >= 0, ("m_copym, negative len %d", len));
867 if (off == 0 && m->m_flags & M_PKTHDR)
870 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain"));
880 KASSERT(len == M_COPYALL,
881 ("m_copym, length > size of mbuf chain"));
884 n = m_getl(MLEN, wait, m->m_type, copyhdr ? M_PKTHDR : 0, NULL);
889 if (!m_dup_pkthdr(n, m, wait))
891 if (len == M_COPYALL)
892 n->m_pkthdr.len -= off0;
894 n->m_pkthdr.len = len;
897 n->m_len = min(len, m->m_len - off);
898 if (m->m_flags & M_EXT) {
899 n->m_data = m->m_data + off;
900 m->m_ext.ext_ref(m->m_ext.ext_arg);
902 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER);
904 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
907 if (len != M_COPYALL)
923 * Copy an entire packet, including header (which must be present).
924 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
925 * Note that the copy is read-only, because clusters are not copied,
926 * only their reference counts are incremented.
927 * Preserve alignment of the first mbuf so if the creator has left
928 * some room at the beginning (e.g. for inserting protocol headers)
929 * the copies also have the room available.
932 m_copypacket(struct mbuf *m, int how)
934 struct mbuf *top, *n, *o;
936 n = m_gethdr(how, m->m_type);
941 if (!m_dup_pkthdr(n, m, how))
944 if (m->m_flags & M_EXT) {
945 n->m_data = m->m_data;
946 m->m_ext.ext_ref(m->m_ext.ext_arg);
948 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER);
950 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat );
951 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
956 o = m_get(how, m->m_type);
964 if (m->m_flags & M_EXT) {
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 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
983 * Copy data from an mbuf chain starting "off" bytes from the beginning,
984 * continuing for "len" bytes, into the indicated buffer.
987 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp)
991 KASSERT(off >= 0, ("m_copydata, negative off %d", off));
992 KASSERT(len >= 0, ("m_copydata, negative len %d", len));
994 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain"));
1001 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain"));
1002 count = min(m->m_len - off, len);
1003 bcopy(mtod(m, caddr_t) + off, cp, count);
1012 * Copy a packet header mbuf chain into a completely new chain, including
1013 * copying any mbuf clusters. Use this instead of m_copypacket() when
1014 * you need a writable copy of an mbuf chain.
1017 m_dup(struct mbuf *m, int how)
1019 struct mbuf **p, *top = NULL;
1020 int remain, moff, nsize;
1025 KASSERT((m->m_flags & M_PKTHDR) != 0, ("%s: !PKTHDR", __func__));
1027 /* While there's more data, get a new mbuf, tack it on, and fill it */
1028 remain = m->m_pkthdr.len;
1031 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */
1034 /* Get the next new mbuf */
1035 n = m_getl(remain, how, m->m_type, top == NULL ? M_PKTHDR : 0,
1040 if (!m_dup_pkthdr(n, m, how))
1043 /* Link it into the new chain */
1047 /* Copy data from original mbuf(s) into new mbuf */
1049 while (n->m_len < nsize && m != NULL) {
1050 int chunk = min(nsize - n->m_len, m->m_len - moff);
1052 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk);
1056 if (moff == m->m_len) {
1062 /* Check correct total mbuf length */
1063 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL),
1064 ("%s: bogus m_pkthdr.len", __func__));
1076 * Concatenate mbuf chain n to m.
1077 * Both chains must be of the same type (e.g. MT_DATA).
1078 * Any m_pkthdr is not updated.
1081 m_cat(struct mbuf *m, struct mbuf *n)
1085 if (m->m_flags & M_EXT ||
1086 m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) {
1087 /* just join the two chains */
1091 /* splat the data from one into the other */
1092 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1094 m->m_len += n->m_len;
1100 m_adj(struct mbuf *mp, int req_len)
1106 if ((m = mp) == NULL)
1112 while (m != NULL && len > 0) {
1113 if (m->m_len <= len) {
1124 if (mp->m_flags & M_PKTHDR)
1125 m->m_pkthdr.len -= (req_len - len);
1128 * Trim from tail. Scan the mbuf chain,
1129 * calculating its length and finding the last mbuf.
1130 * If the adjustment only affects this mbuf, then just
1131 * adjust and return. Otherwise, rescan and truncate
1132 * after the remaining size.
1138 if (m->m_next == (struct mbuf *)0)
1142 if (m->m_len >= len) {
1144 if (mp->m_flags & M_PKTHDR)
1145 mp->m_pkthdr.len -= len;
1152 * Correct length for chain is "count".
1153 * Find the mbuf with last data, adjust its length,
1154 * and toss data from remaining mbufs on chain.
1157 if (m->m_flags & M_PKTHDR)
1158 m->m_pkthdr.len = count;
1159 for (; m; m = m->m_next) {
1160 if (m->m_len >= count) {
1167 (m = m->m_next) ->m_len = 0;
1172 * Rearrange an mbuf chain so that len bytes are contiguous
1173 * and in the data area of an mbuf (so that mtod will work for a structure
1174 * of size len). Returns the resulting mbuf chain on success, frees it and
1175 * returns null on failure. If there is room, it will add up to
1176 * max_protohdr-len extra bytes to the contiguous region in an attempt to
1177 * avoid being called next time.
1180 m_pullup(struct mbuf *n, int len)
1187 * If first mbuf has no cluster, and has room for len bytes
1188 * without shifting current data, pullup into it,
1189 * otherwise allocate a new mbuf to prepend to the chain.
1191 if (!(n->m_flags & M_EXT) &&
1192 n->m_data + len < &n->m_dat[MLEN] &&
1194 if (n->m_len >= len)
1202 m = m_getl(MLEN, MB_DONTWAIT, n->m_type, n->m_flags & M_PKTHDR,
1207 if (n->m_flags & M_PKTHDR)
1208 M_MOVE_PKTHDR(m, n);
1210 space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
1212 count = min(min(max(len, max_protohdr), space), n->m_len);
1213 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1223 } while (len > 0 && n);
1237 * Partition an mbuf chain in two pieces, returning the tail --
1238 * all but the first len0 bytes. In case of failure, it returns NULL and
1239 * attempts to restore the chain to its original state.
1241 * Note that the resulting mbufs might be read-only, because the new
1242 * mbuf can end up sharing an mbuf cluster with the original mbuf if
1243 * the "breaking point" happens to lie within a cluster mbuf. Use the
1244 * M_WRITABLE() macro to check for this case.
1247 m_split(struct mbuf *m0, int len0, int wait)
1250 unsigned len = len0, remain;
1252 for (m = m0; m && len > m->m_len; m = m->m_next)
1256 remain = m->m_len - len;
1257 if (m0->m_flags & M_PKTHDR) {
1258 n = m_gethdr(wait, m0->m_type);
1261 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
1262 n->m_pkthdr.len = m0->m_pkthdr.len - len0;
1263 m0->m_pkthdr.len = len0;
1264 if (m->m_flags & M_EXT)
1266 if (remain > MHLEN) {
1267 /* m can't be the lead packet */
1269 n->m_next = m_split(m, len, wait);
1270 if (n->m_next == NULL) {
1278 MH_ALIGN(n, remain);
1279 } else if (remain == 0) {
1284 n = m_get(wait, m->m_type);
1290 if (m->m_flags & M_EXT) {
1291 n->m_data = m->m_data + len;
1292 m->m_ext.ext_ref(m->m_ext.ext_arg);
1293 n->m_ext = m->m_ext;
1294 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER);
1296 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain);
1300 n->m_next = m->m_next;
1306 * Routine to copy from device local memory into mbufs.
1307 * Note: "offset" is ill-defined and always called as 0, so ignore it.
1310 m_devget(char *buf, int len, int offset, struct ifnet *ifp,
1311 void (*copy)(volatile const void *from, volatile void *to, size_t length))
1313 struct mbuf *m, *mfirst = NULL, **mtail;
1322 m = m_getl(len, MB_DONTWAIT, MT_DATA, flags, &nsize);
1327 m->m_len = min(len, nsize);
1329 if (flags & M_PKTHDR) {
1330 if (len + max_linkhdr <= nsize)
1331 m->m_data += max_linkhdr;
1332 m->m_pkthdr.rcvif = ifp;
1333 m->m_pkthdr.len = len;
1337 copy(buf, m->m_data, (unsigned)m->m_len);
1348 * Copy data from a buffer back into the indicated mbuf chain,
1349 * starting "off" bytes from the beginning, extending the mbuf
1350 * chain if necessary.
1353 m_copyback(struct mbuf *m0, int off, int len, caddr_t cp)
1356 struct mbuf *m = m0, *n;
1361 while (off > (mlen = m->m_len)) {
1364 if (m->m_next == NULL) {
1365 n = m_getclr(MB_DONTWAIT, m->m_type);
1368 n->m_len = min(MLEN, len + off);
1374 mlen = min (m->m_len - off, len);
1375 bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen);
1383 if (m->m_next == NULL) {
1384 n = m_get(MB_DONTWAIT, m->m_type);
1387 n->m_len = min(MLEN, len);
1392 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
1393 m->m_pkthdr.len = totlen;
1397 m_print(const struct mbuf *m)
1400 const struct mbuf *m2;
1402 len = m->m_pkthdr.len;
1405 printf("%p %*D\n", m2, m2->m_len, (u_char *)m2->m_data, "-");
1413 * "Move" mbuf pkthdr from "from" to "to".
1414 * "from" must have M_PKTHDR set, and "to" must be empty.
1417 m_move_pkthdr(struct mbuf *to, struct mbuf *from)
1419 KASSERT((to->m_flags & M_PKTHDR), ("m_move_pkthdr: not packet header"));
1421 to->m_flags |= from->m_flags & M_COPYFLAGS;
1422 to->m_pkthdr = from->m_pkthdr; /* especially tags */
1423 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */
1427 * Duplicate "from"'s mbuf pkthdr in "to".
1428 * "from" must have M_PKTHDR set, and "to" must be empty.
1429 * In particular, this does a deep copy of the packet tags.
1432 m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how)
1434 KASSERT((to->m_flags & M_PKTHDR), ("m_dup_pkthdr: not packet header"));
1436 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
1437 to->m_pkthdr = from->m_pkthdr;
1438 SLIST_INIT(&to->m_pkthdr.tags);
1439 return (m_tag_copy_chain(to, from, how));
1443 * Defragment a mbuf chain, returning the shortest possible
1444 * chain of mbufs and clusters. If allocation fails and
1445 * this cannot be completed, NULL will be returned, but
1446 * the passed in chain will be unchanged. Upon success,
1447 * the original chain will be freed, and the new chain
1450 * If a non-packet header is passed in, the original
1451 * mbuf (chain?) will be returned unharmed.
1453 * m_defrag_nofree doesn't free the passed in mbuf.
1456 m_defrag(struct mbuf *m0, int how)
1460 if ((m_new = m_defrag_nofree(m0, how)) == NULL)
1468 m_defrag_nofree(struct mbuf *m0, int how)
1470 struct mbuf *m_new = NULL, *m_final = NULL;
1471 int progress = 0, length, nsize;
1473 if (!(m0->m_flags & M_PKTHDR))
1476 #ifdef MBUF_STRESS_TEST
1477 if (m_defragrandomfailures) {
1478 int temp = arc4random() & 0xff;
1484 m_final = m_getl(m0->m_pkthdr.len, how, MT_DATA, M_PKTHDR, &nsize);
1485 if (m_final == NULL)
1487 m_final->m_len = 0; /* in case m0->m_pkthdr.len is zero */
1489 if (m_dup_pkthdr(m_final, m0, how) == NULL)
1494 while (progress < m0->m_pkthdr.len) {
1495 length = m0->m_pkthdr.len - progress;
1496 if (length > MCLBYTES)
1499 if (m_new == NULL) {
1500 m_new = m_getl(length, how, MT_DATA, 0, &nsize);
1505 m_copydata(m0, progress, length, mtod(m_new, caddr_t));
1507 m_new->m_len = length;
1508 if (m_new != m_final)
1509 m_cat(m_final, m_new);
1512 if (m0->m_next == NULL)
1515 m_defragbytes += m_final->m_pkthdr.len;
1526 * Move data from uio into mbufs.
1529 m_uiomove(struct uio *uio)
1531 struct mbuf *m; /* current working mbuf */
1532 struct mbuf *head = NULL; /* result mbuf chain */
1533 struct mbuf **mp = &head;
1534 int resid = uio->uio_resid, nsize, flags = M_PKTHDR, error;
1537 m = m_getl(resid, MB_WAIT, MT_DATA, flags, &nsize);
1539 m->m_pkthdr.len = 0;
1540 /* Leave room for protocol headers. */
1545 m->m_len = min(nsize, resid);
1546 error = uiomove(mtod(m, caddr_t), m->m_len, uio);
1553 head->m_pkthdr.len += m->m_len;
1555 } while (resid > 0);
1565 m_last(struct mbuf *m)
1573 * Return the number of bytes in an mbuf chain.
1574 * If lastm is not NULL, also return the last mbuf.
1577 m_lengthm(struct mbuf *m, struct mbuf **lastm)
1580 struct mbuf *prev = m;
1593 * Like m_lengthm(), except also keep track of mbuf usage.
1596 m_countm(struct mbuf *m, struct mbuf **lastm, u_int *pmbcnt)
1598 u_int len = 0, mbcnt = 0;
1599 struct mbuf *prev = m;
1604 if (m->m_flags & M_EXT)
1605 mbcnt += m->m_ext.ext_size;