4 * Copyright (c) 2004 Jeffrey M. Hsu. All rights reserved.
5 * Copyright (c) 2004 The DragonFly Project. All rights reserved.
7 * This code is derived from software contributed to The DragonFly Project
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of The DragonFly Project nor the names of its
19 * contributors may be used to endorse or promote products derived
20 * from this software without specific, prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
26 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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28 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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30 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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37 * Copyright (c) 1982, 1986, 1988, 1991, 1993
38 * The Regents of the University of California. All rights reserved.
40 * Redistribution and use in source and binary forms, with or without
41 * modification, are permitted provided that the following conditions
43 * 1. Redistributions of source code must retain the above copyright
44 * notice, this list of conditions and the following disclaimer.
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53 * may be used to endorse or promote products derived from this software
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63 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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65 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
68 * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94
69 * $FreeBSD: src/sys/kern/uipc_mbuf.c,v 1.51.2.24 2003/04/15 06:59:29 silby Exp $
70 * $DragonFly: src/sys/kern/uipc_mbuf.c,v 1.70 2008/11/20 14:21:01 sephe Exp $
73 #include "opt_param.h"
74 #include "opt_mbuf_stress_test.h"
75 #include <sys/param.h>
76 #include <sys/systm.h>
78 #include <sys/malloc.h>
80 #include <sys/kernel.h>
81 #include <sys/sysctl.h>
82 #include <sys/domain.h>
83 #include <sys/objcache.h>
85 #include <sys/protosw.h>
87 #include <sys/thread.h>
88 #include <sys/globaldata.h>
90 #include <sys/thread2.h>
91 #include <sys/spinlock2.h>
93 #include <machine/atomic.h>
94 #include <machine/limits.h>
97 #include <vm/vm_kern.h>
98 #include <vm/vm_extern.h>
101 #include <machine/cpu.h>
105 * mbuf cluster meta-data
113 * mbuf tracking for debugging purposes
117 static MALLOC_DEFINE(M_MTRACK, "mtrack", "mtrack");
120 RB_HEAD(mbuf_rb_tree, mbtrack);
121 RB_PROTOTYPE2(mbuf_rb_tree, mbtrack, rb_node, mbtrack_cmp, struct mbuf *);
124 RB_ENTRY(mbtrack) rb_node;
130 mbtrack_cmp(struct mbtrack *mb1, struct mbtrack *mb2)
139 RB_GENERATE2(mbuf_rb_tree, mbtrack, rb_node, mbtrack_cmp, struct mbuf *, m);
141 struct mbuf_rb_tree mbuf_track_root;
142 static struct spinlock mbuf_track_spin = SPINLOCK_INITIALIZER(mbuf_track_spin);
145 mbuftrack(struct mbuf *m)
149 mbt = kmalloc(sizeof(*mbt), M_MTRACK, M_INTWAIT|M_ZERO);
150 spin_lock(&mbuf_track_spin);
152 if (mbuf_rb_tree_RB_INSERT(&mbuf_track_root, mbt)) {
153 spin_unlock(&mbuf_track_spin);
154 panic("mbuftrack: mbuf %p already being tracked\n", m);
156 spin_unlock(&mbuf_track_spin);
160 mbufuntrack(struct mbuf *m)
164 spin_lock(&mbuf_track_spin);
165 mbt = mbuf_rb_tree_RB_LOOKUP(&mbuf_track_root, m);
167 spin_unlock(&mbuf_track_spin);
168 panic("mbufuntrack: mbuf %p was not tracked\n", m);
170 mbuf_rb_tree_RB_REMOVE(&mbuf_track_root, mbt);
171 spin_unlock(&mbuf_track_spin);
172 kfree(mbt, M_MTRACK);
177 mbuftrackid(struct mbuf *m, int trackid)
182 spin_lock(&mbuf_track_spin);
186 mbt = mbuf_rb_tree_RB_LOOKUP(&mbuf_track_root, m);
188 spin_unlock(&mbuf_track_spin);
189 panic("mbuftrackid: mbuf %p not tracked", m);
191 mbt->trackid = trackid;
196 spin_unlock(&mbuf_track_spin);
200 mbuftrack_callback(struct mbtrack *mbt, void *arg)
202 struct sysctl_req *req = arg;
206 ksnprintf(buf, sizeof(buf), "mbuf %p track %d\n", mbt->m, mbt->trackid);
208 spin_unlock(&mbuf_track_spin);
209 error = SYSCTL_OUT(req, buf, strlen(buf));
210 spin_lock(&mbuf_track_spin);
217 mbuftrack_show(SYSCTL_HANDLER_ARGS)
221 spin_lock(&mbuf_track_spin);
222 error = mbuf_rb_tree_RB_SCAN(&mbuf_track_root, NULL,
223 mbuftrack_callback, req);
224 spin_unlock(&mbuf_track_spin);
227 SYSCTL_PROC(_kern_ipc, OID_AUTO, showmbufs, CTLFLAG_RD|CTLTYPE_STRING,
228 0, 0, mbuftrack_show, "A", "Show all in-use mbufs");
233 #define mbufuntrack(m)
237 static void mbinit(void *);
238 SYSINIT(mbuf, SI_BOOT2_MACHDEP, SI_ORDER_FIRST, mbinit, NULL)
240 static u_long mbtypes[SMP_MAXCPU][MT_NTYPES];
242 static struct mbstat mbstat[SMP_MAXCPU];
251 #ifdef MBUF_STRESS_TEST
252 int m_defragrandomfailures;
255 struct objcache *mbuf_cache, *mbufphdr_cache;
256 struct objcache *mclmeta_cache, *mjclmeta_cache;
257 struct objcache *mbufcluster_cache, *mbufphdrcluster_cache;
258 struct objcache *mbufjcluster_cache, *mbufphdrjcluster_cache;
263 SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW,
264 &max_linkhdr, 0, "Max size of a link-level header");
265 SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW,
266 &max_protohdr, 0, "Max size of a protocol header");
267 SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0,
268 "Max size of link+protocol headers");
269 SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW,
270 &max_datalen, 0, "Max data payload size without headers");
271 SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_wait, CTLFLAG_RW,
272 &mbuf_wait, 0, "Time in ticks to sleep after failed mbuf allocations");
273 static int do_mbstat(SYSCTL_HANDLER_ARGS);
275 SYSCTL_PROC(_kern_ipc, KIPC_MBSTAT, mbstat, CTLTYPE_STRUCT|CTLFLAG_RD,
276 0, 0, do_mbstat, "S,mbstat", "mbuf usage statistics");
278 static int do_mbtypes(SYSCTL_HANDLER_ARGS);
280 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbtypes, CTLTYPE_ULONG|CTLFLAG_RD,
281 0, 0, do_mbtypes, "LU", "");
284 do_mbstat(SYSCTL_HANDLER_ARGS)
286 struct mbstat mbstat_total;
287 struct mbstat *mbstat_totalp;
290 bzero(&mbstat_total, sizeof(mbstat_total));
291 mbstat_totalp = &mbstat_total;
293 for (i = 0; i < ncpus; i++)
295 mbstat_total.m_mbufs += mbstat[i].m_mbufs;
296 mbstat_total.m_clusters += mbstat[i].m_clusters;
297 mbstat_total.m_spare += mbstat[i].m_spare;
298 mbstat_total.m_clfree += mbstat[i].m_clfree;
299 mbstat_total.m_drops += mbstat[i].m_drops;
300 mbstat_total.m_wait += mbstat[i].m_wait;
301 mbstat_total.m_drain += mbstat[i].m_drain;
302 mbstat_total.m_mcfail += mbstat[i].m_mcfail;
303 mbstat_total.m_mpfail += mbstat[i].m_mpfail;
307 * The following fields are not cumulative fields so just
308 * get their values once.
310 mbstat_total.m_msize = mbstat[0].m_msize;
311 mbstat_total.m_mclbytes = mbstat[0].m_mclbytes;
312 mbstat_total.m_minclsize = mbstat[0].m_minclsize;
313 mbstat_total.m_mlen = mbstat[0].m_mlen;
314 mbstat_total.m_mhlen = mbstat[0].m_mhlen;
316 return(sysctl_handle_opaque(oidp, mbstat_totalp, sizeof(mbstat_total), req));
320 do_mbtypes(SYSCTL_HANDLER_ARGS)
322 u_long totals[MT_NTYPES];
325 for (i = 0; i < MT_NTYPES; i++)
328 for (i = 0; i < ncpus; i++)
330 for (j = 0; j < MT_NTYPES; j++)
331 totals[j] += mbtypes[i][j];
334 return(sysctl_handle_opaque(oidp, totals, sizeof(totals), req));
338 * These are read-only because we do not currently have any code
339 * to adjust the objcache limits after the fact. The variables
340 * may only be set as boot-time tunables.
342 SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters, CTLFLAG_RD,
343 &nmbclusters, 0, "Maximum number of mbuf clusters available");
344 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbufs, CTLFLAG_RD, &nmbufs, 0,
345 "Maximum number of mbufs available");
347 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD,
348 &m_defragpackets, 0, "Number of defragment packets");
349 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD,
350 &m_defragbytes, 0, "Number of defragment bytes");
351 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD,
352 &m_defraguseless, 0, "Number of useless defragment mbuf chain operations");
353 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD,
354 &m_defragfailure, 0, "Number of failed defragment mbuf chain operations");
355 #ifdef MBUF_STRESS_TEST
356 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW,
357 &m_defragrandomfailures, 0, "");
360 static MALLOC_DEFINE(M_MBUF, "mbuf", "mbuf");
361 static MALLOC_DEFINE(M_MBUFCL, "mbufcl", "mbufcl");
362 static MALLOC_DEFINE(M_MJBUFCL, "mbufcl", "mbufcl");
363 static MALLOC_DEFINE(M_MCLMETA, "mclmeta", "mclmeta");
364 static MALLOC_DEFINE(M_MJCLMETA, "mjclmeta", "mjclmeta");
366 static void m_reclaim (void);
367 static void m_mclref(void *arg);
368 static void m_mclfree(void *arg);
371 * NOTE: Default NMBUFS must take into account a possible DOS attack
372 * using fd passing on unix domain sockets.
375 #define NMBCLUSTERS (512 + maxusers * 16)
378 #define NMBUFS (nmbclusters * 2 + maxfiles)
382 * Perform sanity checks of tunables declared above.
385 tunable_mbinit(void *dummy)
388 * This has to be done before VM init.
390 nmbclusters = NMBCLUSTERS;
391 TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
393 TUNABLE_INT_FETCH("kern.ipc.nmbufs", &nmbufs);
395 if (nmbufs < nmbclusters * 2)
396 nmbufs = nmbclusters * 2;
398 SYSINIT(tunable_mbinit, SI_BOOT1_TUNABLES, SI_ORDER_ANY,
399 tunable_mbinit, NULL);
401 /* "number of clusters of pages" */
407 * The mbuf object cache only guarantees that m_next and m_nextpkt are
408 * NULL and that m_data points to the beginning of the data area. In
409 * particular, m_len and m_pkthdr.len are uninitialized. It is the
410 * responsibility of the caller to initialize those fields before use.
413 static boolean_t __inline
414 mbuf_ctor(void *obj, void *private, int ocflags)
416 struct mbuf *m = obj;
420 m->m_data = m->m_dat;
427 * Initialize the mbuf and the packet header fields.
430 mbufphdr_ctor(void *obj, void *private, int ocflags)
432 struct mbuf *m = obj;
436 m->m_data = m->m_pktdat;
437 m->m_flags = M_PKTHDR | M_PHCACHE;
439 m->m_pkthdr.rcvif = NULL; /* eliminate XXX JH */
440 SLIST_INIT(&m->m_pkthdr.tags);
441 m->m_pkthdr.csum_flags = 0; /* eliminate XXX JH */
442 m->m_pkthdr.fw_flags = 0; /* eliminate XXX JH */
448 * A mbcluster object consists of 2K (MCLBYTES) cluster and a refcount.
451 mclmeta_ctor(void *obj, void *private, int ocflags)
453 struct mbcluster *cl = obj;
456 if (ocflags & M_NOWAIT)
457 buf = kmalloc(MCLBYTES, M_MBUFCL, M_NOWAIT | M_ZERO);
459 buf = kmalloc(MCLBYTES, M_MBUFCL, M_INTWAIT | M_ZERO);
468 mjclmeta_ctor(void *obj, void *private, int ocflags)
470 struct mbcluster *cl = obj;
473 if (ocflags & M_NOWAIT)
474 buf = kmalloc(MJUMPAGESIZE, M_MBUFCL, M_NOWAIT | M_ZERO);
476 buf = kmalloc(MJUMPAGESIZE, M_MBUFCL, M_INTWAIT | M_ZERO);
485 mclmeta_dtor(void *obj, void *private)
487 struct mbcluster *mcl = obj;
489 KKASSERT(mcl->mcl_refs == 0);
490 kfree(mcl->mcl_data, M_MBUFCL);
494 linkjcluster(struct mbuf *m, struct mbcluster *cl, uint size)
497 * Add the cluster to the mbuf. The caller will detect that the
498 * mbuf now has an attached cluster.
500 m->m_ext.ext_arg = cl;
501 m->m_ext.ext_buf = cl->mcl_data;
502 m->m_ext.ext_ref = m_mclref;
503 m->m_ext.ext_free = m_mclfree;
504 m->m_ext.ext_size = size;
505 atomic_add_int(&cl->mcl_refs, 1);
507 m->m_data = m->m_ext.ext_buf;
508 m->m_flags |= M_EXT | M_EXT_CLUSTER;
512 linkcluster(struct mbuf *m, struct mbcluster *cl)
514 linkjcluster(m, cl, MCLBYTES);
518 mbufphdrcluster_ctor(void *obj, void *private, int ocflags)
520 struct mbuf *m = obj;
521 struct mbcluster *cl;
523 mbufphdr_ctor(obj, private, ocflags);
524 cl = objcache_get(mclmeta_cache, ocflags);
526 ++mbstat[mycpu->gd_cpuid].m_drops;
529 m->m_flags |= M_CLCACHE;
535 mbufphdrjcluster_ctor(void *obj, void *private, int ocflags)
537 struct mbuf *m = obj;
538 struct mbcluster *cl;
540 mbufphdr_ctor(obj, private, ocflags);
541 cl = objcache_get(mjclmeta_cache, ocflags);
543 ++mbstat[mycpu->gd_cpuid].m_drops;
546 m->m_flags |= M_CLCACHE;
547 linkjcluster(m, cl, MJUMPAGESIZE);
552 mbufcluster_ctor(void *obj, void *private, int ocflags)
554 struct mbuf *m = obj;
555 struct mbcluster *cl;
557 mbuf_ctor(obj, private, ocflags);
558 cl = objcache_get(mclmeta_cache, ocflags);
560 ++mbstat[mycpu->gd_cpuid].m_drops;
563 m->m_flags |= M_CLCACHE;
569 mbufjcluster_ctor(void *obj, void *private, int ocflags)
571 struct mbuf *m = obj;
572 struct mbcluster *cl;
574 mbuf_ctor(obj, private, ocflags);
575 cl = objcache_get(mjclmeta_cache, ocflags);
577 ++mbstat[mycpu->gd_cpuid].m_drops;
580 m->m_flags |= M_CLCACHE;
581 linkjcluster(m, cl, MJUMPAGESIZE);
586 * Used for both the cluster and cluster PHDR caches.
588 * The mbuf may have lost its cluster due to sharing, deal
589 * with the situation by checking M_EXT.
592 mbufcluster_dtor(void *obj, void *private)
594 struct mbuf *m = obj;
595 struct mbcluster *mcl;
597 if (m->m_flags & M_EXT) {
598 KKASSERT((m->m_flags & M_EXT_CLUSTER) != 0);
599 mcl = m->m_ext.ext_arg;
600 KKASSERT(mcl->mcl_refs == 1);
602 if (m->m_flags & M_EXT && m->m_ext.ext_size != MCLBYTES)
603 objcache_put(mjclmeta_cache, mcl);
605 objcache_put(mclmeta_cache, mcl);
609 struct objcache_malloc_args mbuf_malloc_args = { MSIZE, M_MBUF };
610 struct objcache_malloc_args mclmeta_malloc_args =
611 { sizeof(struct mbcluster), M_MCLMETA };
617 int mb_limit, cl_limit;
622 * Initialize statistics
624 for (i = 0; i < ncpus; i++) {
625 atomic_set_long_nonlocked(&mbstat[i].m_msize, MSIZE);
626 atomic_set_long_nonlocked(&mbstat[i].m_mclbytes, MCLBYTES);
627 atomic_set_long_nonlocked(&mbstat[i].m_mjumpagesize, MJUMPAGESIZE);
628 atomic_set_long_nonlocked(&mbstat[i].m_minclsize, MINCLSIZE);
629 atomic_set_long_nonlocked(&mbstat[i].m_mlen, MLEN);
630 atomic_set_long_nonlocked(&mbstat[i].m_mhlen, MHLEN);
634 * Create objtect caches and save cluster limits, which will
635 * be used to adjust backing kmalloc pools' limit later.
638 mb_limit = cl_limit = 0;
641 mbuf_cache = objcache_create("mbuf",
643 mbuf_ctor, NULL, NULL,
644 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
648 mbufphdr_cache = objcache_create("mbuf pkt hdr",
650 mbufphdr_ctor, NULL, NULL,
651 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
654 cl_limit = nmbclusters;
655 mclmeta_cache = objcache_create("cluster mbuf",
657 mclmeta_ctor, mclmeta_dtor, NULL,
658 objcache_malloc_alloc, objcache_malloc_free, &mclmeta_malloc_args);
660 cl_limit = nmbclusters;
661 mjclmeta_cache = objcache_create("jcluster mbuf",
663 mjclmeta_ctor, mclmeta_dtor, NULL,
664 objcache_malloc_alloc, objcache_malloc_free, &mclmeta_malloc_args);
667 mbufcluster_cache = objcache_create("mbuf + cluster",
669 mbufcluster_ctor, mbufcluster_dtor, NULL,
670 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
674 mbufphdrcluster_cache = objcache_create("mbuf pkt hdr + cluster",
675 &limit, nmbclusters / 16,
676 mbufphdrcluster_ctor, mbufcluster_dtor, NULL,
677 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
681 mbufjcluster_cache = objcache_create("mbuf + jcluster",
683 mbufjcluster_ctor, mbufcluster_dtor, NULL,
684 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
688 mbufphdrjcluster_cache = objcache_create("mbuf pkt hdr + jcluster",
689 &limit, nmbclusters / 16,
690 mbufphdrjcluster_ctor, mbufcluster_dtor, NULL,
691 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
695 * Adjust backing kmalloc pools' limit
697 * NOTE: We raise the limit by another 1/8 to take the effect
698 * of loosememuse into account.
700 cl_limit += cl_limit / 8;
701 kmalloc_raise_limit(mclmeta_malloc_args.mtype,
702 mclmeta_malloc_args.objsize * cl_limit);
703 kmalloc_raise_limit(M_MBUFCL, MCLBYTES * cl_limit * 3/4 + MJUMPAGESIZE * cl_limit / 4);
704 /*kmalloc_raise_limit(M_MBUFCL, MCLBYTES * cl_limit);*/
706 mb_limit += mb_limit / 8;
707 kmalloc_raise_limit(mbuf_malloc_args.mtype,
708 mbuf_malloc_args.objsize * mb_limit);
712 * Return the number of references to this mbuf's data. 0 is returned
713 * if the mbuf is not M_EXT, a reference count is returned if it is
714 * M_EXT | M_EXT_CLUSTER, and 99 is returned if it is a special M_EXT.
717 m_sharecount(struct mbuf *m)
719 switch (m->m_flags & (M_EXT | M_EXT_CLUSTER)) {
724 case M_EXT | M_EXT_CLUSTER:
725 return (((struct mbcluster *)m->m_ext.ext_arg)->mcl_refs);
728 return (0); /* to shut up compiler */
732 * change mbuf to new type
735 m_chtype(struct mbuf *m, int type)
737 struct globaldata *gd = mycpu;
739 atomic_add_long_nonlocked(&mbtypes[gd->gd_cpuid][type], 1);
740 atomic_subtract_long_nonlocked(&mbtypes[gd->gd_cpuid][m->m_type], 1);
741 atomic_set_short_nonlocked(&m->m_type, type);
750 kprintf("Debug: m_reclaim() called\n");
752 SLIST_FOREACH(dp, &domains, dom_next) {
753 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) {
758 atomic_add_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_drain, 1);
762 updatestats(struct mbuf *m, int type)
764 struct globaldata *gd = mycpu;
769 KASSERT(m->m_next == NULL, ("mbuf %p: bad m_next in get", m));
770 KASSERT(m->m_nextpkt == NULL, ("mbuf %p: bad m_nextpkt in get", m));
773 atomic_add_long_nonlocked(&mbtypes[gd->gd_cpuid][type], 1);
774 atomic_add_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_mbufs, 1);
782 m_get(int how, int type)
786 int ocf = MBTOM(how);
790 m = objcache_get(mbuf_cache, ocf);
793 if ((how & MB_TRYWAIT) && ntries++ == 0) {
794 struct objcache *reclaimlist[] = {
797 mbufphdrcluster_cache,
799 mbufphdrjcluster_cache
801 const int nreclaims = NELEM(reclaimlist);
803 if (!objcache_reclaimlist(reclaimlist, nreclaims, ocf))
807 ++mbstat[mycpu->gd_cpuid].m_drops;
811 KASSERT(m->m_data == m->m_dat, ("mbuf %p: bad m_data in get", m));
815 updatestats(m, type);
820 m_gethdr(int how, int type)
823 int ocf = MBTOM(how);
828 m = objcache_get(mbufphdr_cache, ocf);
831 if ((how & MB_TRYWAIT) && ntries++ == 0) {
832 struct objcache *reclaimlist[] = {
834 mbufcluster_cache, mbufphdrcluster_cache,
835 mbufjcluster_cache, mbufphdrjcluster_cache
837 const int nreclaims = NELEM(reclaimlist);
839 if (!objcache_reclaimlist(reclaimlist, nreclaims, ocf))
843 ++mbstat[mycpu->gd_cpuid].m_drops;
847 KASSERT(m->m_data == m->m_pktdat, ("mbuf %p: bad m_data in get", m));
852 updatestats(m, type);
857 * Get a mbuf (not a mbuf cluster!) and zero it.
861 m_getclr(int how, int type)
865 m = m_get(how, type);
867 bzero(m->m_data, MLEN);
872 m_getjcl(int how, short type, int flags, size_t size)
874 struct mbuf *m = NULL;
875 struct objcache *mbclc, *mbphclc;
876 int ocflags = MBTOM(how);
881 mbclc = mbufcluster_cache;
882 mbphclc = mbufphdrcluster_cache;
885 mbclc = mbufjcluster_cache;
886 mbphclc = mbufphdrjcluster_cache;
892 if (flags & M_PKTHDR)
893 m = objcache_get(mbphclc, ocflags);
895 m = objcache_get(mbclc, ocflags);
898 if ((how & MB_TRYWAIT) && ntries++ == 0) {
899 struct objcache *reclaimlist[1];
901 if (flags & M_PKTHDR)
902 reclaimlist[0] = mbclc;
904 reclaimlist[0] = mbphclc;
905 if (!objcache_reclaimlist(reclaimlist, 1, ocflags))
909 ++mbstat[mycpu->gd_cpuid].m_drops;
914 KASSERT(m->m_data == m->m_ext.ext_buf,
915 ("mbuf %p: bad m_data in get", m));
919 m->m_pkthdr.len = 0; /* just do it unconditonally */
923 atomic_add_long_nonlocked(&mbtypes[mycpu->gd_cpuid][type], 1);
924 atomic_add_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_clusters, 1);
929 * Returns an mbuf with an attached cluster.
930 * Because many network drivers use this kind of buffers a lot, it is
931 * convenient to keep a small pool of free buffers of this kind.
932 * Even a small size such as 10 gives about 10% improvement in the
933 * forwarding rate in a bridge or router.
936 m_getcl(int how, short type, int flags)
938 return (m_getjcl(how, type, flags, MCLBYTES));
942 * Allocate chain of requested length.
945 m_getc(int len, int how, int type)
947 struct mbuf *n, *nfirst = NULL, **ntail = &nfirst;
951 n = m_getl(len, how, type, 0, &nsize);
967 * Allocate len-worth of mbufs and/or mbuf clusters (whatever fits best)
968 * and return a pointer to the head of the allocated chain. If m0 is
969 * non-null, then we assume that it is a single mbuf or an mbuf chain to
970 * which we want len bytes worth of mbufs and/or clusters attached, and so
971 * if we succeed in allocating it, we will just return a pointer to m0.
973 * If we happen to fail at any point during the allocation, we will free
974 * up everything we have already allocated and return NULL.
976 * Deprecated. Use m_getc() and m_cat() instead.
979 m_getm(struct mbuf *m0, int len, int type, int how)
983 nfirst = m_getc(len, how, type);
986 m_last(m0)->m_next = nfirst;
994 * Adds a cluster to a normal mbuf, M_EXT is set on success.
995 * Deprecated. Use m_getcl() instead.
998 m_mclget(struct mbuf *m, int how)
1000 struct mbcluster *mcl;
1002 KKASSERT((m->m_flags & M_EXT) == 0);
1003 mcl = objcache_get(mclmeta_cache, MBTOM(how));
1005 linkcluster(m, mcl);
1006 atomic_add_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_clusters,
1009 ++mbstat[mycpu->gd_cpuid].m_drops;
1014 * Updates to mbcluster must be MPSAFE. Only an entity which already has
1015 * a reference to the cluster can ref it, so we are in no danger of
1016 * racing an add with a subtract. But the operation must still be atomic
1017 * since multiple entities may have a reference on the cluster.
1019 * m_mclfree() is almost the same but it must contend with two entities
1020 * freeing the cluster at the same time.
1025 struct mbcluster *mcl = arg;
1027 atomic_add_int(&mcl->mcl_refs, 1);
1031 * When dereferencing a cluster we have to deal with a N->0 race, where
1032 * N entities free their references simultaniously. To do this we use
1033 * atomic_fetchadd_int().
1036 m_mclfree(void *arg)
1038 struct mbcluster *mcl = arg;
1040 if (atomic_fetchadd_int(&mcl->mcl_refs, -1) == 1)
1041 objcache_put(mclmeta_cache, mcl);
1045 * Free a single mbuf and any associated external storage. The successor,
1046 * if any, is returned.
1048 * We do need to check non-first mbuf for m_aux, since some of existing
1049 * code does not call M_PREPEND properly.
1050 * (example: call to bpf_mtap from drivers)
1056 _m_free(struct mbuf *m, const char *func)
1061 m_free(struct mbuf *m)
1066 struct globaldata *gd = mycpu;
1068 KASSERT(m->m_type != MT_FREE, ("freeing free mbuf %p", m));
1069 KASSERT(M_TRAILINGSPACE(m) >= 0, ("overflowed mbuf %p", m));
1070 atomic_subtract_long_nonlocked(&mbtypes[gd->gd_cpuid][m->m_type], 1);
1075 * Make sure the mbuf is in constructed state before returning it
1081 m->m_hdr.mh_lastfunc = func;
1084 KKASSERT(m->m_nextpkt == NULL);
1086 if (m->m_nextpkt != NULL) {
1087 static int afewtimes = 10;
1089 if (afewtimes-- > 0) {
1090 kprintf("mfree: m->m_nextpkt != NULL\n");
1091 print_backtrace(-1);
1093 m->m_nextpkt = NULL;
1096 if (m->m_flags & M_PKTHDR) {
1097 m_tag_delete_chain(m); /* eliminate XXX JH */
1100 m->m_flags &= (M_EXT | M_EXT_CLUSTER | M_CLCACHE | M_PHCACHE);
1103 * Clean the M_PKTHDR state so we can return the mbuf to its original
1104 * cache. This is based on the PHCACHE flag which tells us whether
1105 * the mbuf was originally allocated out of a packet-header cache
1106 * or a non-packet-header cache.
1108 if (m->m_flags & M_PHCACHE) {
1109 m->m_flags |= M_PKTHDR;
1110 m->m_pkthdr.rcvif = NULL; /* eliminate XXX JH */
1111 m->m_pkthdr.csum_flags = 0; /* eliminate XXX JH */
1112 m->m_pkthdr.fw_flags = 0; /* eliminate XXX JH */
1113 SLIST_INIT(&m->m_pkthdr.tags);
1117 * Handle remaining flags combinations. M_CLCACHE tells us whether
1118 * the mbuf was originally allocated from a cluster cache or not,
1119 * and is totally separate from whether the mbuf is currently
1120 * associated with a cluster.
1122 switch(m->m_flags & (M_CLCACHE | M_EXT | M_EXT_CLUSTER)) {
1123 case M_CLCACHE | M_EXT | M_EXT_CLUSTER:
1125 * mbuf+cluster cache case. The mbuf was allocated from the
1126 * combined mbuf_cluster cache and can be returned to the
1127 * cache if the cluster hasn't been shared.
1129 if (m_sharecount(m) == 1) {
1131 * The cluster has not been shared, we can just
1132 * reset the data pointer and return the mbuf
1133 * to the cluster cache. Note that the reference
1134 * count is left intact (it is still associated with
1137 m->m_data = m->m_ext.ext_buf;
1138 if (m->m_flags & M_EXT && m->m_ext.ext_size != MCLBYTES) {
1139 if (m->m_flags & M_PHCACHE)
1140 objcache_put(mbufphdrjcluster_cache, m);
1142 objcache_put(mbufjcluster_cache, m);
1144 if (m->m_flags & M_PHCACHE)
1145 objcache_put(mbufphdrcluster_cache, m);
1147 objcache_put(mbufcluster_cache, m);
1149 atomic_subtract_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_clusters, 1);
1152 * Hell. Someone else has a ref on this cluster,
1153 * we have to disconnect it which means we can't
1154 * put it back into the mbufcluster_cache, we
1155 * have to destroy the mbuf.
1157 * Other mbuf references to the cluster will typically
1158 * be M_EXT | M_EXT_CLUSTER but without M_CLCACHE.
1160 * XXX we could try to connect another cluster to
1164 m->m_ext.ext_free(m->m_ext.ext_arg);
1165 m->m_flags &= ~(M_EXT | M_EXT_CLUSTER);
1166 if (m->m_ext.ext_size == MCLBYTES) {
1167 if (m->m_flags & M_PHCACHE)
1168 objcache_dtor(mbufphdrcluster_cache, m);
1170 objcache_dtor(mbufcluster_cache, m);
1172 if (m->m_flags & M_PHCACHE)
1173 objcache_dtor(mbufphdrjcluster_cache, m);
1175 objcache_dtor(mbufjcluster_cache, m);
1179 case M_EXT | M_EXT_CLUSTER:
1181 * Normal cluster associated with an mbuf that was allocated
1182 * from the normal mbuf pool rather then the cluster pool.
1183 * The cluster has to be independantly disassociated from the
1186 if (m_sharecount(m) == 1)
1187 atomic_subtract_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_clusters, 1);
1191 * Normal cluster association case, disconnect the cluster from
1192 * the mbuf. The cluster may or may not be custom.
1194 m->m_ext.ext_free(m->m_ext.ext_arg);
1195 m->m_flags &= ~(M_EXT | M_EXT_CLUSTER);
1199 * return the mbuf to the mbuf cache.
1201 if (m->m_flags & M_PHCACHE) {
1202 m->m_data = m->m_pktdat;
1203 objcache_put(mbufphdr_cache, m);
1205 m->m_data = m->m_dat;
1206 objcache_put(mbuf_cache, m);
1208 atomic_subtract_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_mbufs, 1);
1212 panic("bad mbuf flags %p %08x\n", m, m->m_flags);
1221 _m_freem(struct mbuf *m, const char *func)
1224 m = _m_free(m, func);
1230 m_freem(struct mbuf *m)
1239 * mbuf utility routines
1243 * Lesser-used path for M_PREPEND: allocate new mbuf to prepend to chain and
1247 m_prepend(struct mbuf *m, int len, int how)
1251 if (m->m_flags & M_PKTHDR)
1252 mn = m_gethdr(how, m->m_type);
1254 mn = m_get(how, m->m_type);
1259 if (m->m_flags & M_PKTHDR)
1260 M_MOVE_PKTHDR(mn, m);
1270 * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
1271 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf.
1272 * The wait parameter is a choice of MB_WAIT/MB_DONTWAIT from caller.
1273 * Note that the copy is read-only, because clusters are not copied,
1274 * only their reference counts are incremented.
1277 m_copym(const struct mbuf *m, int off0, int len, int wait)
1279 struct mbuf *n, **np;
1284 KASSERT(off >= 0, ("m_copym, negative off %d", off));
1285 KASSERT(len >= 0, ("m_copym, negative len %d", len));
1286 if (off == 0 && (m->m_flags & M_PKTHDR))
1289 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain"));
1299 KASSERT(len == M_COPYALL,
1300 ("m_copym, length > size of mbuf chain"));
1304 * Because we are sharing any cluster attachment below,
1305 * be sure to get an mbuf that does not have a cluster
1306 * associated with it.
1309 n = m_gethdr(wait, m->m_type);
1311 n = m_get(wait, m->m_type);
1316 if (!m_dup_pkthdr(n, m, wait))
1318 if (len == M_COPYALL)
1319 n->m_pkthdr.len -= off0;
1321 n->m_pkthdr.len = len;
1324 n->m_len = min(len, m->m_len - off);
1325 if (m->m_flags & M_EXT) {
1326 KKASSERT((n->m_flags & M_EXT) == 0);
1327 n->m_data = m->m_data + off;
1328 m->m_ext.ext_ref(m->m_ext.ext_arg);
1329 n->m_ext = m->m_ext;
1330 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER);
1332 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
1333 (unsigned)n->m_len);
1335 if (len != M_COPYALL)
1342 atomic_add_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_mcfail, 1);
1346 atomic_add_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_mcfail, 1);
1351 * Copy an entire packet, including header (which must be present).
1352 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
1353 * Note that the copy is read-only, because clusters are not copied,
1354 * only their reference counts are incremented.
1355 * Preserve alignment of the first mbuf so if the creator has left
1356 * some room at the beginning (e.g. for inserting protocol headers)
1357 * the copies also have the room available.
1360 m_copypacket(struct mbuf *m, int how)
1362 struct mbuf *top, *n, *o;
1364 n = m_gethdr(how, m->m_type);
1369 if (!m_dup_pkthdr(n, m, how))
1371 n->m_len = m->m_len;
1372 if (m->m_flags & M_EXT) {
1373 KKASSERT((n->m_flags & M_EXT) == 0);
1374 n->m_data = m->m_data;
1375 m->m_ext.ext_ref(m->m_ext.ext_arg);
1376 n->m_ext = m->m_ext;
1377 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER);
1379 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat );
1380 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
1385 o = m_get(how, m->m_type);
1392 n->m_len = m->m_len;
1393 if (m->m_flags & M_EXT) {
1394 KKASSERT((n->m_flags & M_EXT) == 0);
1395 n->m_data = m->m_data;
1396 m->m_ext.ext_ref(m->m_ext.ext_arg);
1397 n->m_ext = m->m_ext;
1398 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER);
1400 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
1408 atomic_add_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_mcfail, 1);
1413 * Copy data from an mbuf chain starting "off" bytes from the beginning,
1414 * continuing for "len" bytes, into the indicated buffer.
1417 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp)
1421 KASSERT(off >= 0, ("m_copydata, negative off %d", off));
1422 KASSERT(len >= 0, ("m_copydata, negative len %d", len));
1424 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain"));
1431 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain"));
1432 count = min(m->m_len - off, len);
1433 bcopy(mtod(m, caddr_t) + off, cp, count);
1442 * Copy a packet header mbuf chain into a completely new chain, including
1443 * copying any mbuf clusters. Use this instead of m_copypacket() when
1444 * you need a writable copy of an mbuf chain.
1447 m_dup(struct mbuf *m, int how)
1449 struct mbuf **p, *top = NULL;
1450 int remain, moff, nsize;
1455 KASSERT((m->m_flags & M_PKTHDR) != 0, ("%s: !PKTHDR", __func__));
1457 /* While there's more data, get a new mbuf, tack it on, and fill it */
1458 remain = m->m_pkthdr.len;
1461 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */
1464 /* Get the next new mbuf */
1465 n = m_getl(remain, how, m->m_type, top == NULL ? M_PKTHDR : 0,
1470 if (!m_dup_pkthdr(n, m, how))
1473 /* Link it into the new chain */
1477 /* Copy data from original mbuf(s) into new mbuf */
1479 while (n->m_len < nsize && m != NULL) {
1480 int chunk = min(nsize - n->m_len, m->m_len - moff);
1482 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk);
1486 if (moff == m->m_len) {
1492 /* Check correct total mbuf length */
1493 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL),
1494 ("%s: bogus m_pkthdr.len", __func__));
1501 atomic_add_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_mcfail, 1);
1506 * Copy the non-packet mbuf data chain into a new set of mbufs, including
1507 * copying any mbuf clusters. This is typically used to realign a data
1508 * chain by nfs_realign().
1510 * The original chain is left intact. how should be MB_WAIT or MB_DONTWAIT
1511 * and NULL can be returned if MB_DONTWAIT is passed.
1513 * Be careful to use cluster mbufs, a large mbuf chain converted to non
1514 * cluster mbufs can exhaust our supply of mbufs.
1517 m_dup_data(struct mbuf *m, int how)
1519 struct mbuf **p, *n, *top = NULL;
1520 int mlen, moff, chunk, gsize, nsize;
1529 * Optimize the mbuf allocation but do not get too carried away.
1531 if (m->m_next || m->m_len > MLEN)
1532 if (m->m_flags & M_EXT && m->m_ext.ext_size == MCLBYTES)
1535 gsize = MJUMPAGESIZE;
1545 * Scan the mbuf chain until nothing is left, the new mbuf chain
1546 * will be allocated on the fly as needed.
1553 KKASSERT(m->m_type == MT_DATA);
1555 n = m_getl(gsize, how, MT_DATA, 0, &nsize);
1562 chunk = imin(mlen, nsize);
1563 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk);
1578 atomic_add_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_mcfail, 1);
1583 * Concatenate mbuf chain n to m.
1584 * Both chains must be of the same type (e.g. MT_DATA).
1585 * Any m_pkthdr is not updated.
1588 m_cat(struct mbuf *m, struct mbuf *n)
1592 if (m->m_flags & M_EXT ||
1593 m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) {
1594 /* just join the two chains */
1598 /* splat the data from one into the other */
1599 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1601 m->m_len += n->m_len;
1607 m_adj(struct mbuf *mp, int req_len)
1613 if ((m = mp) == NULL)
1619 while (m != NULL && len > 0) {
1620 if (m->m_len <= len) {
1631 if (mp->m_flags & M_PKTHDR)
1632 m->m_pkthdr.len -= (req_len - len);
1635 * Trim from tail. Scan the mbuf chain,
1636 * calculating its length and finding the last mbuf.
1637 * If the adjustment only affects this mbuf, then just
1638 * adjust and return. Otherwise, rescan and truncate
1639 * after the remaining size.
1645 if (m->m_next == NULL)
1649 if (m->m_len >= len) {
1651 if (mp->m_flags & M_PKTHDR)
1652 mp->m_pkthdr.len -= len;
1659 * Correct length for chain is "count".
1660 * Find the mbuf with last data, adjust its length,
1661 * and toss data from remaining mbufs on chain.
1664 if (m->m_flags & M_PKTHDR)
1665 m->m_pkthdr.len = count;
1666 for (; m; m = m->m_next) {
1667 if (m->m_len >= count) {
1674 (m = m->m_next) ->m_len = 0;
1679 * Set the m_data pointer of a newly-allocated mbuf
1680 * to place an object of the specified size at the
1681 * end of the mbuf, longword aligned.
1684 m_align(struct mbuf *m, int len)
1688 if (m->m_flags & M_EXT)
1689 adjust = m->m_ext.ext_size - len;
1690 else if (m->m_flags & M_PKTHDR)
1691 adjust = MHLEN - len;
1693 adjust = MLEN - len;
1694 m->m_data += adjust &~ (sizeof(long)-1);
1698 * Rearrange an mbuf chain so that len bytes are contiguous
1699 * and in the data area of an mbuf (so that mtod will work for a structure
1700 * of size len). Returns the resulting mbuf chain on success, frees it and
1701 * returns null on failure. If there is room, it will add up to
1702 * max_protohdr-len extra bytes to the contiguous region in an attempt to
1703 * avoid being called next time.
1706 m_pullup(struct mbuf *n, int len)
1713 * If first mbuf has no cluster, and has room for len bytes
1714 * without shifting current data, pullup into it,
1715 * otherwise allocate a new mbuf to prepend to the chain.
1717 if (!(n->m_flags & M_EXT) &&
1718 n->m_data + len < &n->m_dat[MLEN] &&
1720 if (n->m_len >= len)
1728 if (n->m_flags & M_PKTHDR)
1729 m = m_gethdr(MB_DONTWAIT, n->m_type);
1731 m = m_get(MB_DONTWAIT, n->m_type);
1735 if (n->m_flags & M_PKTHDR)
1736 M_MOVE_PKTHDR(m, n);
1738 space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
1740 count = min(min(max(len, max_protohdr), space), n->m_len);
1741 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1751 } while (len > 0 && n);
1760 atomic_add_long_nonlocked(&mbstat[mycpu->gd_cpuid].m_mcfail, 1);
1765 * Partition an mbuf chain in two pieces, returning the tail --
1766 * all but the first len0 bytes. In case of failure, it returns NULL and
1767 * attempts to restore the chain to its original state.
1769 * Note that the resulting mbufs might be read-only, because the new
1770 * mbuf can end up sharing an mbuf cluster with the original mbuf if
1771 * the "breaking point" happens to lie within a cluster mbuf. Use the
1772 * M_WRITABLE() macro to check for this case.
1775 m_split(struct mbuf *m0, int len0, int wait)
1778 unsigned len = len0, remain;
1780 for (m = m0; m && len > m->m_len; m = m->m_next)
1784 remain = m->m_len - len;
1785 if (m0->m_flags & M_PKTHDR) {
1786 n = m_gethdr(wait, m0->m_type);
1789 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
1790 n->m_pkthdr.len = m0->m_pkthdr.len - len0;
1791 m0->m_pkthdr.len = len0;
1792 if (m->m_flags & M_EXT)
1794 if (remain > MHLEN) {
1795 /* m can't be the lead packet */
1797 n->m_next = m_split(m, len, wait);
1798 if (n->m_next == NULL) {
1806 MH_ALIGN(n, remain);
1807 } else if (remain == 0) {
1812 n = m_get(wait, m->m_type);
1818 if (m->m_flags & M_EXT) {
1819 KKASSERT((n->m_flags & M_EXT) == 0);
1820 n->m_data = m->m_data + len;
1821 m->m_ext.ext_ref(m->m_ext.ext_arg);
1822 n->m_ext = m->m_ext;
1823 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER);
1825 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain);
1829 n->m_next = m->m_next;
1835 * Routine to copy from device local memory into mbufs.
1836 * Note: "offset" is ill-defined and always called as 0, so ignore it.
1839 m_devget(char *buf, int len, int offset, struct ifnet *ifp,
1840 void (*copy)(volatile const void *from, volatile void *to, size_t length))
1842 struct mbuf *m, *mfirst = NULL, **mtail;
1851 m = m_getl(len, MB_DONTWAIT, MT_DATA, flags, &nsize);
1856 m->m_len = min(len, nsize);
1858 if (flags & M_PKTHDR) {
1859 if (len + max_linkhdr <= nsize)
1860 m->m_data += max_linkhdr;
1861 m->m_pkthdr.rcvif = ifp;
1862 m->m_pkthdr.len = len;
1866 copy(buf, m->m_data, (unsigned)m->m_len);
1877 * Routine to pad mbuf to the specified length 'padto'.
1880 m_devpad(struct mbuf *m, int padto)
1882 struct mbuf *last = NULL;
1885 if (padto <= m->m_pkthdr.len)
1888 padlen = padto - m->m_pkthdr.len;
1890 /* if there's only the packet-header and we can pad there, use it. */
1891 if (m->m_pkthdr.len == m->m_len && M_TRAILINGSPACE(m) >= padlen) {
1895 * Walk packet chain to find last mbuf. We will either
1896 * pad there, or append a new mbuf and pad it
1898 for (last = m; last->m_next != NULL; last = last->m_next)
1901 /* `last' now points to last in chain. */
1902 if (M_TRAILINGSPACE(last) < padlen) {
1905 /* Allocate new empty mbuf, pad it. Compact later. */
1906 MGET(n, MB_DONTWAIT, MT_DATA);
1914 KKASSERT(M_TRAILINGSPACE(last) >= padlen);
1915 KKASSERT(M_WRITABLE(last));
1917 /* Now zero the pad area */
1918 bzero(mtod(last, char *) + last->m_len, padlen);
1919 last->m_len += padlen;
1920 m->m_pkthdr.len += padlen;
1925 * Copy data from a buffer back into the indicated mbuf chain,
1926 * starting "off" bytes from the beginning, extending the mbuf
1927 * chain if necessary.
1930 m_copyback(struct mbuf *m0, int off, int len, caddr_t cp)
1933 struct mbuf *m = m0, *n;
1938 while (off > (mlen = m->m_len)) {
1941 if (m->m_next == NULL) {
1942 n = m_getclr(MB_DONTWAIT, m->m_type);
1945 n->m_len = min(MLEN, len + off);
1951 mlen = min (m->m_len - off, len);
1952 bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen);
1960 if (m->m_next == NULL) {
1961 n = m_get(MB_DONTWAIT, m->m_type);
1964 n->m_len = min(MLEN, len);
1969 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
1970 m->m_pkthdr.len = totlen;
1974 * Append the specified data to the indicated mbuf chain,
1975 * Extend the mbuf chain if the new data does not fit in
1978 * Return 1 if able to complete the job; otherwise 0.
1981 m_append(struct mbuf *m0, int len, c_caddr_t cp)
1984 int remainder, space;
1986 for (m = m0; m->m_next != NULL; m = m->m_next)
1989 space = M_TRAILINGSPACE(m);
1992 * Copy into available space.
1994 if (space > remainder)
1996 bcopy(cp, mtod(m, caddr_t) + m->m_len, space);
1998 cp += space, remainder -= space;
2000 while (remainder > 0) {
2002 * Allocate a new mbuf; could check space
2003 * and allocate a cluster instead.
2005 n = m_get(MB_DONTWAIT, m->m_type);
2008 n->m_len = min(MLEN, remainder);
2009 bcopy(cp, mtod(n, caddr_t), n->m_len);
2010 cp += n->m_len, remainder -= n->m_len;
2014 if (m0->m_flags & M_PKTHDR)
2015 m0->m_pkthdr.len += len - remainder;
2016 return (remainder == 0);
2020 * Apply function f to the data in an mbuf chain starting "off" bytes from
2021 * the beginning, continuing for "len" bytes.
2024 m_apply(struct mbuf *m, int off, int len,
2025 int (*f)(void *, void *, u_int), void *arg)
2030 KASSERT(off >= 0, ("m_apply, negative off %d", off));
2031 KASSERT(len >= 0, ("m_apply, negative len %d", len));
2033 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
2040 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
2041 count = min(m->m_len - off, len);
2042 rval = (*f)(arg, mtod(m, caddr_t) + off, count);
2053 * Return a pointer to mbuf/offset of location in mbuf chain.
2056 m_getptr(struct mbuf *m, int loc, int *off)
2060 /* Normal end of search. */
2061 if (m->m_len > loc) {
2066 if (m->m_next == NULL) {
2068 /* Point at the end of valid data. */
2081 m_print(const struct mbuf *m)
2084 const struct mbuf *m2;
2086 len = m->m_pkthdr.len;
2089 kprintf("%p %*D\n", m2, m2->m_len, (u_char *)m2->m_data, "-");
2097 * "Move" mbuf pkthdr from "from" to "to".
2098 * "from" must have M_PKTHDR set, and "to" must be empty.
2101 m_move_pkthdr(struct mbuf *to, struct mbuf *from)
2103 KASSERT((to->m_flags & M_PKTHDR), ("m_move_pkthdr: not packet header"));
2105 to->m_flags |= from->m_flags & M_COPYFLAGS;
2106 to->m_pkthdr = from->m_pkthdr; /* especially tags */
2107 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */
2111 * Duplicate "from"'s mbuf pkthdr in "to".
2112 * "from" must have M_PKTHDR set, and "to" must be empty.
2113 * In particular, this does a deep copy of the packet tags.
2116 m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how)
2118 KASSERT((to->m_flags & M_PKTHDR), ("m_dup_pkthdr: not packet header"));
2120 to->m_flags = (from->m_flags & M_COPYFLAGS) |
2121 (to->m_flags & ~M_COPYFLAGS);
2122 to->m_pkthdr = from->m_pkthdr;
2123 SLIST_INIT(&to->m_pkthdr.tags);
2124 return (m_tag_copy_chain(to, from, how));
2128 * Defragment a mbuf chain, returning the shortest possible
2129 * chain of mbufs and clusters. If allocation fails and
2130 * this cannot be completed, NULL will be returned, but
2131 * the passed in chain will be unchanged. Upon success,
2132 * the original chain will be freed, and the new chain
2135 * If a non-packet header is passed in, the original
2136 * mbuf (chain?) will be returned unharmed.
2138 * m_defrag_nofree doesn't free the passed in mbuf.
2141 m_defrag(struct mbuf *m0, int how)
2145 if ((m_new = m_defrag_nofree(m0, how)) == NULL)
2153 m_defrag_nofree(struct mbuf *m0, int how)
2155 struct mbuf *m_new = NULL, *m_final = NULL;
2156 int progress = 0, length, nsize;
2158 if (!(m0->m_flags & M_PKTHDR))
2161 #ifdef MBUF_STRESS_TEST
2162 if (m_defragrandomfailures) {
2163 int temp = karc4random() & 0xff;
2169 m_final = m_getl(m0->m_pkthdr.len, how, MT_DATA, M_PKTHDR, &nsize);
2170 if (m_final == NULL)
2172 m_final->m_len = 0; /* in case m0->m_pkthdr.len is zero */
2174 if (m_dup_pkthdr(m_final, m0, how) == 0)
2179 while (progress < m0->m_pkthdr.len) {
2180 length = m0->m_pkthdr.len - progress;
2181 if (length > MCLBYTES)
2184 if (m_new == NULL) {
2185 m_new = m_getl(length, how, MT_DATA, 0, &nsize);
2190 m_copydata(m0, progress, length, mtod(m_new, caddr_t));
2192 m_new->m_len = length;
2193 if (m_new != m_final)
2194 m_cat(m_final, m_new);
2197 if (m0->m_next == NULL)
2200 m_defragbytes += m_final->m_pkthdr.len;
2211 * Move data from uio into mbufs.
2214 m_uiomove(struct uio *uio)
2216 struct mbuf *m; /* current working mbuf */
2217 struct mbuf *head = NULL; /* result mbuf chain */
2218 struct mbuf **mp = &head;
2219 int flags = M_PKTHDR;
2225 if (uio->uio_resid > INT_MAX)
2228 resid = (int)uio->uio_resid;
2229 m = m_getl(resid, MB_WAIT, MT_DATA, flags, &nsize);
2231 m->m_pkthdr.len = 0;
2232 /* Leave room for protocol headers. */
2237 m->m_len = imin(nsize, resid);
2238 error = uiomove(mtod(m, caddr_t), m->m_len, uio);
2245 head->m_pkthdr.len += m->m_len;
2246 } while (uio->uio_resid > 0);
2256 m_last(struct mbuf *m)
2264 * Return the number of bytes in an mbuf chain.
2265 * If lastm is not NULL, also return the last mbuf.
2268 m_lengthm(struct mbuf *m, struct mbuf **lastm)
2271 struct mbuf *prev = m;
2284 * Like m_lengthm(), except also keep track of mbuf usage.
2287 m_countm(struct mbuf *m, struct mbuf **lastm, u_int *pmbcnt)
2289 u_int len = 0, mbcnt = 0;
2290 struct mbuf *prev = m;
2295 if (m->m_flags & M_EXT)
2296 mbcnt += m->m_ext.ext_size;