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
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17 * documentation and/or other materials provided with the distribution.
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64 * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94
65 * $FreeBSD: src/sys/kern/uipc_mbuf.c,v 1.51.2.24 2003/04/15 06:59:29 silby Exp $
68 #include "opt_param.h"
69 #include "opt_mbuf_stress_test.h"
70 #include <sys/param.h>
71 #include <sys/systm.h>
73 #include <sys/malloc.h>
75 #include <sys/kernel.h>
76 #include <sys/sysctl.h>
77 #include <sys/domain.h>
78 #include <sys/objcache.h>
80 #include <sys/protosw.h>
82 #include <sys/thread.h>
83 #include <sys/globaldata.h>
85 #include <sys/thread2.h>
86 #include <sys/spinlock2.h>
88 #include <machine/atomic.h>
89 #include <machine/limits.h>
92 #include <vm/vm_kern.h>
93 #include <vm/vm_extern.h>
96 #include <machine/cpu.h>
100 * mbuf cluster meta-data
108 * mbuf tracking for debugging purposes
112 static MALLOC_DEFINE(M_MTRACK, "mtrack", "mtrack");
115 RB_HEAD(mbuf_rb_tree, mbtrack);
116 RB_PROTOTYPE2(mbuf_rb_tree, mbtrack, rb_node, mbtrack_cmp, struct mbuf *);
119 RB_ENTRY(mbtrack) rb_node;
125 mbtrack_cmp(struct mbtrack *mb1, struct mbtrack *mb2)
134 RB_GENERATE2(mbuf_rb_tree, mbtrack, rb_node, mbtrack_cmp, struct mbuf *, m);
136 struct mbuf_rb_tree mbuf_track_root;
137 static struct spinlock mbuf_track_spin = SPINLOCK_INITIALIZER(mbuf_track_spin);
140 mbuftrack(struct mbuf *m)
144 mbt = kmalloc(sizeof(*mbt), M_MTRACK, M_INTWAIT|M_ZERO);
145 spin_lock(&mbuf_track_spin);
147 if (mbuf_rb_tree_RB_INSERT(&mbuf_track_root, mbt)) {
148 spin_unlock(&mbuf_track_spin);
149 panic("mbuftrack: mbuf %p already being tracked", m);
151 spin_unlock(&mbuf_track_spin);
155 mbufuntrack(struct mbuf *m)
159 spin_lock(&mbuf_track_spin);
160 mbt = mbuf_rb_tree_RB_LOOKUP(&mbuf_track_root, m);
162 spin_unlock(&mbuf_track_spin);
163 panic("mbufuntrack: mbuf %p was not tracked", m);
165 mbuf_rb_tree_RB_REMOVE(&mbuf_track_root, mbt);
166 spin_unlock(&mbuf_track_spin);
167 kfree(mbt, M_MTRACK);
172 mbuftrackid(struct mbuf *m, int trackid)
177 spin_lock(&mbuf_track_spin);
181 mbt = mbuf_rb_tree_RB_LOOKUP(&mbuf_track_root, m);
183 spin_unlock(&mbuf_track_spin);
184 panic("mbuftrackid: mbuf %p not tracked", m);
186 mbt->trackid = trackid;
191 spin_unlock(&mbuf_track_spin);
195 mbuftrack_callback(struct mbtrack *mbt, void *arg)
197 struct sysctl_req *req = arg;
201 ksnprintf(buf, sizeof(buf), "mbuf %p track %d\n", mbt->m, mbt->trackid);
203 spin_unlock(&mbuf_track_spin);
204 error = SYSCTL_OUT(req, buf, strlen(buf));
205 spin_lock(&mbuf_track_spin);
212 mbuftrack_show(SYSCTL_HANDLER_ARGS)
216 spin_lock(&mbuf_track_spin);
217 error = mbuf_rb_tree_RB_SCAN(&mbuf_track_root, NULL,
218 mbuftrack_callback, req);
219 spin_unlock(&mbuf_track_spin);
222 SYSCTL_PROC(_kern_ipc, OID_AUTO, showmbufs, CTLFLAG_RD|CTLTYPE_STRING,
223 0, 0, mbuftrack_show, "A", "Show all in-use mbufs");
228 #define mbufuntrack(m)
232 static void mbinit(void *);
233 SYSINIT(mbuf, SI_BOOT2_MACHDEP, SI_ORDER_FIRST, mbinit, NULL)
235 static u_long mbtypes[SMP_MAXCPU][MT_NTYPES];
237 static struct mbstat mbstat[SMP_MAXCPU];
246 #ifdef MBUF_STRESS_TEST
247 int m_defragrandomfailures;
250 struct objcache *mbuf_cache, *mbufphdr_cache;
251 struct objcache *mclmeta_cache, *mjclmeta_cache;
252 struct objcache *mbufcluster_cache, *mbufphdrcluster_cache;
253 struct objcache *mbufjcluster_cache, *mbufphdrjcluster_cache;
256 static int nmbjclusters;
259 static int mclph_cachefrac;
260 static int mcl_cachefrac;
262 SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW,
263 &max_linkhdr, 0, "Max size of a link-level header");
264 SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW,
265 &max_protohdr, 0, "Max size of a protocol header");
266 SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0,
267 "Max size of link+protocol headers");
268 SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW,
269 &max_datalen, 0, "Max data payload size without headers");
270 SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_wait, CTLFLAG_RW,
271 &mbuf_wait, 0, "Time in ticks to sleep after failed mbuf allocations");
272 static int do_mbstat(SYSCTL_HANDLER_ARGS);
274 SYSCTL_PROC(_kern_ipc, KIPC_MBSTAT, mbstat, CTLTYPE_STRUCT|CTLFLAG_RD,
275 0, 0, do_mbstat, "S,mbstat", "mbuf usage statistics");
277 static int do_mbtypes(SYSCTL_HANDLER_ARGS);
279 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbtypes, CTLTYPE_ULONG|CTLFLAG_RD,
280 0, 0, do_mbtypes, "LU", "");
283 do_mbstat(SYSCTL_HANDLER_ARGS)
285 struct mbstat mbstat_total;
286 struct mbstat *mbstat_totalp;
289 bzero(&mbstat_total, sizeof(mbstat_total));
290 mbstat_totalp = &mbstat_total;
292 for (i = 0; i < ncpus; i++)
294 mbstat_total.m_mbufs += mbstat[i].m_mbufs;
295 mbstat_total.m_clusters += mbstat[i].m_clusters;
296 mbstat_total.m_spare += mbstat[i].m_spare;
297 mbstat_total.m_clfree += mbstat[i].m_clfree;
298 mbstat_total.m_drops += mbstat[i].m_drops;
299 mbstat_total.m_wait += mbstat[i].m_wait;
300 mbstat_total.m_drain += mbstat[i].m_drain;
301 mbstat_total.m_mcfail += mbstat[i].m_mcfail;
302 mbstat_total.m_mpfail += mbstat[i].m_mpfail;
306 * The following fields are not cumulative fields so just
307 * get their values once.
309 mbstat_total.m_msize = mbstat[0].m_msize;
310 mbstat_total.m_mclbytes = mbstat[0].m_mclbytes;
311 mbstat_total.m_minclsize = mbstat[0].m_minclsize;
312 mbstat_total.m_mlen = mbstat[0].m_mlen;
313 mbstat_total.m_mhlen = mbstat[0].m_mhlen;
315 return(sysctl_handle_opaque(oidp, mbstat_totalp, sizeof(mbstat_total), req));
319 do_mbtypes(SYSCTL_HANDLER_ARGS)
321 u_long totals[MT_NTYPES];
324 for (i = 0; i < MT_NTYPES; i++)
327 for (i = 0; i < ncpus; i++)
329 for (j = 0; j < MT_NTYPES; j++)
330 totals[j] += mbtypes[i][j];
333 return(sysctl_handle_opaque(oidp, totals, sizeof(totals), req));
337 * These are read-only because we do not currently have any code
338 * to adjust the objcache limits after the fact. The variables
339 * may only be set as boot-time tunables.
341 SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters, CTLFLAG_RD,
342 &nmbclusters, 0, "Maximum number of mbuf clusters available");
343 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbufs, CTLFLAG_RD, &nmbufs, 0,
344 "Maximum number of mbufs available");
345 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbjclusters, CTLFLAG_RD, &nmbjclusters, 0,
346 "Maximum number of mbuf jclusters available");
347 SYSCTL_INT(_kern_ipc, OID_AUTO, mclph_cachefrac, CTLFLAG_RD,
349 "Fraction of cacheable mbuf clusters w/ pkthdr");
350 SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_cachefrac, CTLFLAG_RD,
351 &mcl_cachefrac, 0, "Fraction of cacheable mbuf clusters");
353 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD,
354 &m_defragpackets, 0, "Number of defragment packets");
355 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD,
356 &m_defragbytes, 0, "Number of defragment bytes");
357 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD,
358 &m_defraguseless, 0, "Number of useless defragment mbuf chain operations");
359 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD,
360 &m_defragfailure, 0, "Number of failed defragment mbuf chain operations");
361 #ifdef MBUF_STRESS_TEST
362 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW,
363 &m_defragrandomfailures, 0, "");
366 static MALLOC_DEFINE(M_MBUF, "mbuf", "mbuf");
367 static MALLOC_DEFINE(M_MBUFCL, "mbufcl", "mbufcl");
368 static MALLOC_DEFINE(M_MCLMETA, "mclmeta", "mclmeta");
370 static void m_reclaim (void);
371 static void m_mclref(void *arg);
372 static void m_mclfree(void *arg);
375 * NOTE: Default NMBUFS must take into account a possible DOS attack
376 * using fd passing on unix domain sockets.
379 #define NMBCLUSTERS (512 + maxusers * 16)
381 #ifndef MCLPH_CACHEFRAC
382 #define MCLPH_CACHEFRAC 16
384 #ifndef MCL_CACHEFRAC
385 #define MCL_CACHEFRAC 4
388 #define NMBJCLUSTERS 2048
391 #define NMBUFS (nmbclusters * 2 + maxfiles)
395 * Perform sanity checks of tunables declared above.
398 tunable_mbinit(void *dummy)
401 * This has to be done before VM init.
403 nmbclusters = NMBCLUSTERS;
404 TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
405 mclph_cachefrac = MCLPH_CACHEFRAC;
406 TUNABLE_INT_FETCH("kern.ipc.mclph_cachefrac", &mclph_cachefrac);
407 mcl_cachefrac = MCL_CACHEFRAC;
408 TUNABLE_INT_FETCH("kern.ipc.mcl_cachefrac", &mcl_cachefrac);
410 nmbjclusters = NMBJCLUSTERS;
411 TUNABLE_INT_FETCH("kern.ipc.nmbjclusters", &nmbjclusters);
414 TUNABLE_INT_FETCH("kern.ipc.nmbufs", &nmbufs);
417 if (nmbufs < nmbclusters * 2)
418 nmbufs = nmbclusters * 2;
420 SYSINIT(tunable_mbinit, SI_BOOT1_TUNABLES, SI_ORDER_ANY,
421 tunable_mbinit, NULL);
423 /* "number of clusters of pages" */
429 * The mbuf object cache only guarantees that m_next and m_nextpkt are
430 * NULL and that m_data points to the beginning of the data area. In
431 * particular, m_len and m_pkthdr.len are uninitialized. It is the
432 * responsibility of the caller to initialize those fields before use.
435 static __inline boolean_t
436 mbuf_ctor(void *obj, void *private, int ocflags)
438 struct mbuf *m = obj;
442 m->m_data = m->m_dat;
449 * Initialize the mbuf and the packet header fields.
452 mbufphdr_ctor(void *obj, void *private, int ocflags)
454 struct mbuf *m = obj;
458 m->m_data = m->m_pktdat;
459 m->m_flags = M_PKTHDR | M_PHCACHE;
461 m->m_pkthdr.rcvif = NULL; /* eliminate XXX JH */
462 SLIST_INIT(&m->m_pkthdr.tags);
463 m->m_pkthdr.csum_flags = 0; /* eliminate XXX JH */
464 m->m_pkthdr.fw_flags = 0; /* eliminate XXX JH */
470 * A mbcluster object consists of 2K (MCLBYTES) cluster and a refcount.
473 mclmeta_ctor(void *obj, void *private, int ocflags)
475 struct mbcluster *cl = obj;
478 if (ocflags & M_NOWAIT)
479 buf = kmalloc(MCLBYTES, M_MBUFCL, M_NOWAIT | M_ZERO);
481 buf = kmalloc(MCLBYTES, M_MBUFCL, M_INTWAIT | M_ZERO);
490 mjclmeta_ctor(void *obj, void *private, int ocflags)
492 struct mbcluster *cl = obj;
495 if (ocflags & M_NOWAIT)
496 buf = kmalloc(MJUMPAGESIZE, M_MBUFCL, M_NOWAIT | M_ZERO);
498 buf = kmalloc(MJUMPAGESIZE, M_MBUFCL, M_INTWAIT | M_ZERO);
507 mclmeta_dtor(void *obj, void *private)
509 struct mbcluster *mcl = obj;
511 KKASSERT(mcl->mcl_refs == 0);
512 kfree(mcl->mcl_data, M_MBUFCL);
516 linkjcluster(struct mbuf *m, struct mbcluster *cl, uint size)
519 * Add the cluster to the mbuf. The caller will detect that the
520 * mbuf now has an attached cluster.
522 m->m_ext.ext_arg = cl;
523 m->m_ext.ext_buf = cl->mcl_data;
524 m->m_ext.ext_ref = m_mclref;
525 m->m_ext.ext_free = m_mclfree;
526 m->m_ext.ext_size = size;
527 atomic_add_int(&cl->mcl_refs, 1);
529 m->m_data = m->m_ext.ext_buf;
530 m->m_flags |= M_EXT | M_EXT_CLUSTER;
534 linkcluster(struct mbuf *m, struct mbcluster *cl)
536 linkjcluster(m, cl, MCLBYTES);
540 mbufphdrcluster_ctor(void *obj, void *private, int ocflags)
542 struct mbuf *m = obj;
543 struct mbcluster *cl;
545 mbufphdr_ctor(obj, private, ocflags);
546 cl = objcache_get(mclmeta_cache, ocflags);
548 ++mbstat[mycpu->gd_cpuid].m_drops;
551 m->m_flags |= M_CLCACHE;
557 mbufphdrjcluster_ctor(void *obj, void *private, int ocflags)
559 struct mbuf *m = obj;
560 struct mbcluster *cl;
562 mbufphdr_ctor(obj, private, ocflags);
563 cl = objcache_get(mjclmeta_cache, ocflags);
565 ++mbstat[mycpu->gd_cpuid].m_drops;
568 m->m_flags |= M_CLCACHE;
569 linkjcluster(m, cl, MJUMPAGESIZE);
574 mbufcluster_ctor(void *obj, void *private, int ocflags)
576 struct mbuf *m = obj;
577 struct mbcluster *cl;
579 mbuf_ctor(obj, private, ocflags);
580 cl = objcache_get(mclmeta_cache, ocflags);
582 ++mbstat[mycpu->gd_cpuid].m_drops;
585 m->m_flags |= M_CLCACHE;
591 mbufjcluster_ctor(void *obj, void *private, int ocflags)
593 struct mbuf *m = obj;
594 struct mbcluster *cl;
596 mbuf_ctor(obj, private, ocflags);
597 cl = objcache_get(mjclmeta_cache, ocflags);
599 ++mbstat[mycpu->gd_cpuid].m_drops;
602 m->m_flags |= M_CLCACHE;
603 linkjcluster(m, cl, MJUMPAGESIZE);
608 * Used for both the cluster and cluster PHDR caches.
610 * The mbuf may have lost its cluster due to sharing, deal
611 * with the situation by checking M_EXT.
614 mbufcluster_dtor(void *obj, void *private)
616 struct mbuf *m = obj;
617 struct mbcluster *mcl;
619 if (m->m_flags & M_EXT) {
620 KKASSERT((m->m_flags & M_EXT_CLUSTER) != 0);
621 mcl = m->m_ext.ext_arg;
622 KKASSERT(mcl->mcl_refs == 1);
624 if (m->m_flags & M_EXT && m->m_ext.ext_size != MCLBYTES)
625 objcache_put(mjclmeta_cache, mcl);
627 objcache_put(mclmeta_cache, mcl);
631 struct objcache_malloc_args mbuf_malloc_args = { MSIZE, M_MBUF };
632 struct objcache_malloc_args mclmeta_malloc_args =
633 { sizeof(struct mbcluster), M_MCLMETA };
639 int mb_limit, cl_limit, ncl_limit, jcl_limit;
644 * Initialize statistics
646 for (i = 0; i < ncpus; i++) {
647 mbstat[i].m_msize = MSIZE;
648 mbstat[i].m_mclbytes = MCLBYTES;
649 mbstat[i].m_mjumpagesize = MJUMPAGESIZE;
650 mbstat[i].m_minclsize = MINCLSIZE;
651 mbstat[i].m_mlen = MLEN;
652 mbstat[i].m_mhlen = MHLEN;
656 * Create objtect caches and save cluster limits, which will
657 * be used to adjust backing kmalloc pools' limit later.
660 mb_limit = cl_limit = 0;
663 mbuf_cache = objcache_create("mbuf",
665 mbuf_ctor, NULL, NULL,
666 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
670 mbufphdr_cache = objcache_create("mbuf pkt hdr",
672 mbufphdr_ctor, NULL, NULL,
673 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
676 ncl_limit = nmbclusters;
677 mclmeta_cache = objcache_create("cluster mbuf",
679 mclmeta_ctor, mclmeta_dtor, NULL,
680 objcache_malloc_alloc, objcache_malloc_free, &mclmeta_malloc_args);
681 cl_limit += ncl_limit;
683 jcl_limit = nmbjclusters;
684 mjclmeta_cache = objcache_create("jcluster mbuf",
686 mjclmeta_ctor, mclmeta_dtor, NULL,
687 objcache_malloc_alloc, objcache_malloc_free, &mclmeta_malloc_args);
688 cl_limit += jcl_limit;
691 mbufcluster_cache = objcache_create("mbuf + cluster",
692 limit, nmbclusters / mcl_cachefrac,
693 mbufcluster_ctor, mbufcluster_dtor, NULL,
694 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
698 mbufphdrcluster_cache = objcache_create("mbuf pkt hdr + cluster",
699 limit, nmbclusters / mclph_cachefrac,
700 mbufphdrcluster_ctor, mbufcluster_dtor, NULL,
701 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
704 limit = nmbjclusters / 4; /* XXX really rarely used */
705 mbufjcluster_cache = objcache_create("mbuf + jcluster",
707 mbufjcluster_ctor, mbufcluster_dtor, NULL,
708 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
711 limit = nmbjclusters;
712 mbufphdrjcluster_cache = objcache_create("mbuf pkt hdr + jcluster",
713 limit, nmbjclusters / 16,
714 mbufphdrjcluster_ctor, mbufcluster_dtor, NULL,
715 objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args);
719 * Adjust backing kmalloc pools' limit
721 * NOTE: We raise the limit by another 1/8 to take the effect
722 * of loosememuse into account.
724 cl_limit += cl_limit / 8;
725 kmalloc_raise_limit(mclmeta_malloc_args.mtype,
726 mclmeta_malloc_args.objsize * (size_t)cl_limit);
727 kmalloc_raise_limit(M_MBUFCL,
728 (MCLBYTES * (size_t)ncl_limit) +
729 (MJUMPAGESIZE * (size_t)jcl_limit));
731 mb_limit += mb_limit / 8;
732 kmalloc_raise_limit(mbuf_malloc_args.mtype,
733 mbuf_malloc_args.objsize * (size_t)mb_limit);
737 * Return the number of references to this mbuf's data. 0 is returned
738 * if the mbuf is not M_EXT, a reference count is returned if it is
739 * M_EXT | M_EXT_CLUSTER, and 99 is returned if it is a special M_EXT.
742 m_sharecount(struct mbuf *m)
744 switch (m->m_flags & (M_EXT | M_EXT_CLUSTER)) {
749 case M_EXT | M_EXT_CLUSTER:
750 return (((struct mbcluster *)m->m_ext.ext_arg)->mcl_refs);
753 return (0); /* to shut up compiler */
757 * change mbuf to new type
760 m_chtype(struct mbuf *m, int type)
762 struct globaldata *gd = mycpu;
764 ++mbtypes[gd->gd_cpuid][type];
765 --mbtypes[gd->gd_cpuid][m->m_type];
775 kprintf("Debug: m_reclaim() called\n");
777 SLIST_FOREACH(dp, &domains, dom_next) {
778 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) {
783 ++mbstat[mycpu->gd_cpuid].m_drain;
787 updatestats(struct mbuf *m, int type)
789 struct globaldata *gd = mycpu;
794 KASSERT(m->m_next == NULL, ("mbuf %p: bad m_next in get", m));
795 KASSERT(m->m_nextpkt == NULL, ("mbuf %p: bad m_nextpkt in get", m));
798 ++mbtypes[gd->gd_cpuid][type];
799 ++mbstat[gd->gd_cpuid].m_mbufs;
807 m_get(int how, int type)
811 int ocf = MBTOM(how);
815 m = objcache_get(mbuf_cache, ocf);
818 if ((how & MB_TRYWAIT) && ntries++ == 0) {
819 struct objcache *reclaimlist[] = {
822 mbufphdrcluster_cache,
824 mbufphdrjcluster_cache
826 const int nreclaims = NELEM(reclaimlist);
828 if (!objcache_reclaimlist(reclaimlist, nreclaims, ocf))
832 ++mbstat[mycpu->gd_cpuid].m_drops;
836 KASSERT(m->m_data == m->m_dat, ("mbuf %p: bad m_data in get", m));
840 updatestats(m, type);
845 m_gethdr(int how, int type)
848 int ocf = MBTOM(how);
853 m = objcache_get(mbufphdr_cache, ocf);
856 if ((how & MB_TRYWAIT) && ntries++ == 0) {
857 struct objcache *reclaimlist[] = {
859 mbufcluster_cache, mbufphdrcluster_cache,
860 mbufjcluster_cache, mbufphdrjcluster_cache
862 const int nreclaims = NELEM(reclaimlist);
864 if (!objcache_reclaimlist(reclaimlist, nreclaims, ocf))
868 ++mbstat[mycpu->gd_cpuid].m_drops;
872 KASSERT(m->m_data == m->m_pktdat, ("mbuf %p: bad m_data in get", m));
877 updatestats(m, type);
882 * Get a mbuf (not a mbuf cluster!) and zero it.
886 m_getclr(int how, int type)
890 m = m_get(how, type);
892 bzero(m->m_data, MLEN);
897 m_getcl_cache(int how, short type, int flags, struct objcache *mbclc,
898 struct objcache *mbphclc)
900 struct mbuf *m = NULL;
901 int ocflags = MBTOM(how);
906 if (flags & M_PKTHDR)
907 m = objcache_get(mbphclc, ocflags);
909 m = objcache_get(mbclc, ocflags);
912 if ((how & MB_TRYWAIT) && ntries++ == 0) {
913 struct objcache *reclaimlist[1];
915 if (flags & M_PKTHDR)
916 reclaimlist[0] = mbclc;
918 reclaimlist[0] = mbphclc;
919 if (!objcache_reclaimlist(reclaimlist, 1, ocflags))
923 ++mbstat[mycpu->gd_cpuid].m_drops;
928 KASSERT(m->m_data == m->m_ext.ext_buf,
929 ("mbuf %p: bad m_data in get", m));
933 m->m_pkthdr.len = 0; /* just do it unconditonally */
937 ++mbtypes[mycpu->gd_cpuid][type];
938 ++mbstat[mycpu->gd_cpuid].m_clusters;
943 m_getjcl(int how, short type, int flags, size_t size)
945 struct objcache *mbclc, *mbphclc;
949 mbclc = mbufcluster_cache;
950 mbphclc = mbufphdrcluster_cache;
954 mbclc = mbufjcluster_cache;
955 mbphclc = mbufphdrjcluster_cache;
958 return m_getcl_cache(how, type, flags, mbclc, mbphclc);
962 * Returns an mbuf with an attached cluster.
963 * Because many network drivers use this kind of buffers a lot, it is
964 * convenient to keep a small pool of free buffers of this kind.
965 * Even a small size such as 10 gives about 10% improvement in the
966 * forwarding rate in a bridge or router.
969 m_getcl(int how, short type, int flags)
971 return m_getcl_cache(how, type, flags,
972 mbufcluster_cache, mbufphdrcluster_cache);
976 * Allocate chain of requested length.
979 m_getc(int len, int how, int type)
981 struct mbuf *n, *nfirst = NULL, **ntail = &nfirst;
985 n = m_getl(len, how, type, 0, &nsize);
1001 * Allocate len-worth of mbufs and/or mbuf clusters (whatever fits best)
1002 * and return a pointer to the head of the allocated chain. If m0 is
1003 * non-null, then we assume that it is a single mbuf or an mbuf chain to
1004 * which we want len bytes worth of mbufs and/or clusters attached, and so
1005 * if we succeed in allocating it, we will just return a pointer to m0.
1007 * If we happen to fail at any point during the allocation, we will free
1008 * up everything we have already allocated and return NULL.
1010 * Deprecated. Use m_getc() and m_cat() instead.
1013 m_getm(struct mbuf *m0, int len, int type, int how)
1015 struct mbuf *nfirst;
1017 nfirst = m_getc(len, how, type);
1020 m_last(m0)->m_next = nfirst;
1028 * Adds a cluster to a normal mbuf, M_EXT is set on success.
1029 * Deprecated. Use m_getcl() instead.
1032 m_mclget(struct mbuf *m, int how)
1034 struct mbcluster *mcl;
1036 KKASSERT((m->m_flags & M_EXT) == 0);
1037 mcl = objcache_get(mclmeta_cache, MBTOM(how));
1039 linkcluster(m, mcl);
1040 ++mbstat[mycpu->gd_cpuid].m_clusters;
1042 ++mbstat[mycpu->gd_cpuid].m_drops;
1047 * Updates to mbcluster must be MPSAFE. Only an entity which already has
1048 * a reference to the cluster can ref it, so we are in no danger of
1049 * racing an add with a subtract. But the operation must still be atomic
1050 * since multiple entities may have a reference on the cluster.
1052 * m_mclfree() is almost the same but it must contend with two entities
1053 * freeing the cluster at the same time.
1058 struct mbcluster *mcl = arg;
1060 atomic_add_int(&mcl->mcl_refs, 1);
1064 * When dereferencing a cluster we have to deal with a N->0 race, where
1065 * N entities free their references simultaniously. To do this we use
1066 * atomic_fetchadd_int().
1069 m_mclfree(void *arg)
1071 struct mbcluster *mcl = arg;
1073 if (atomic_fetchadd_int(&mcl->mcl_refs, -1) == 1) {
1074 --mbstat[mycpu->gd_cpuid].m_clusters;
1075 objcache_put(mclmeta_cache, mcl);
1080 * Free a single mbuf and any associated external storage. The successor,
1081 * if any, is returned.
1083 * We do need to check non-first mbuf for m_aux, since some of existing
1084 * code does not call M_PREPEND properly.
1085 * (example: call to bpf_mtap from drivers)
1091 _m_free(struct mbuf *m, const char *func)
1096 m_free(struct mbuf *m)
1101 struct globaldata *gd = mycpu;
1103 KASSERT(m->m_type != MT_FREE, ("freeing free mbuf %p", m));
1104 KASSERT(M_TRAILINGSPACE(m) >= 0, ("overflowed mbuf %p", m));
1105 --mbtypes[gd->gd_cpuid][m->m_type];
1110 * Make sure the mbuf is in constructed state before returning it
1116 m->m_hdr.mh_lastfunc = func;
1119 KKASSERT(m->m_nextpkt == NULL);
1121 if (m->m_nextpkt != NULL) {
1122 static int afewtimes = 10;
1124 if (afewtimes-- > 0) {
1125 kprintf("mfree: m->m_nextpkt != NULL\n");
1126 print_backtrace(-1);
1128 m->m_nextpkt = NULL;
1131 if (m->m_flags & M_PKTHDR) {
1132 m_tag_delete_chain(m); /* eliminate XXX JH */
1135 m->m_flags &= (M_EXT | M_EXT_CLUSTER | M_CLCACHE | M_PHCACHE);
1138 * Clean the M_PKTHDR state so we can return the mbuf to its original
1139 * cache. This is based on the PHCACHE flag which tells us whether
1140 * the mbuf was originally allocated out of a packet-header cache
1141 * or a non-packet-header cache.
1143 if (m->m_flags & M_PHCACHE) {
1144 m->m_flags |= M_PKTHDR;
1145 m->m_pkthdr.rcvif = NULL; /* eliminate XXX JH */
1146 m->m_pkthdr.csum_flags = 0; /* eliminate XXX JH */
1147 m->m_pkthdr.fw_flags = 0; /* eliminate XXX JH */
1148 SLIST_INIT(&m->m_pkthdr.tags);
1152 * Handle remaining flags combinations. M_CLCACHE tells us whether
1153 * the mbuf was originally allocated from a cluster cache or not,
1154 * and is totally separate from whether the mbuf is currently
1155 * associated with a cluster.
1157 switch(m->m_flags & (M_CLCACHE | M_EXT | M_EXT_CLUSTER)) {
1158 case M_CLCACHE | M_EXT | M_EXT_CLUSTER:
1160 * mbuf+cluster cache case. The mbuf was allocated from the
1161 * combined mbuf_cluster cache and can be returned to the
1162 * cache if the cluster hasn't been shared.
1164 if (m_sharecount(m) == 1) {
1166 * The cluster has not been shared, we can just
1167 * reset the data pointer and return the mbuf
1168 * to the cluster cache. Note that the reference
1169 * count is left intact (it is still associated with
1172 m->m_data = m->m_ext.ext_buf;
1173 if (m->m_flags & M_EXT && m->m_ext.ext_size != MCLBYTES) {
1174 if (m->m_flags & M_PHCACHE)
1175 objcache_put(mbufphdrjcluster_cache, m);
1177 objcache_put(mbufjcluster_cache, m);
1179 if (m->m_flags & M_PHCACHE)
1180 objcache_put(mbufphdrcluster_cache, m);
1182 objcache_put(mbufcluster_cache, m);
1184 --mbstat[mycpu->gd_cpuid].m_clusters;
1187 * Hell. Someone else has a ref on this cluster,
1188 * we have to disconnect it which means we can't
1189 * put it back into the mbufcluster_cache, we
1190 * have to destroy the mbuf.
1192 * Other mbuf references to the cluster will typically
1193 * be M_EXT | M_EXT_CLUSTER but without M_CLCACHE.
1195 * XXX we could try to connect another cluster to
1198 m->m_ext.ext_free(m->m_ext.ext_arg);
1199 m->m_flags &= ~(M_EXT | M_EXT_CLUSTER);
1200 if (m->m_ext.ext_size == MCLBYTES) {
1201 if (m->m_flags & M_PHCACHE)
1202 objcache_dtor(mbufphdrcluster_cache, m);
1204 objcache_dtor(mbufcluster_cache, m);
1206 if (m->m_flags & M_PHCACHE)
1207 objcache_dtor(mbufphdrjcluster_cache, m);
1209 objcache_dtor(mbufjcluster_cache, m);
1213 case M_EXT | M_EXT_CLUSTER:
1216 * Normal cluster association case, disconnect the cluster from
1217 * the mbuf. The cluster may or may not be custom.
1219 m->m_ext.ext_free(m->m_ext.ext_arg);
1220 m->m_flags &= ~(M_EXT | M_EXT_CLUSTER);
1224 * return the mbuf to the mbuf cache.
1226 if (m->m_flags & M_PHCACHE) {
1227 m->m_data = m->m_pktdat;
1228 objcache_put(mbufphdr_cache, m);
1230 m->m_data = m->m_dat;
1231 objcache_put(mbuf_cache, m);
1233 --mbstat[mycpu->gd_cpuid].m_mbufs;
1237 panic("bad mbuf flags %p %08x", m, m->m_flags);
1246 _m_freem(struct mbuf *m, const char *func)
1249 m = _m_free(m, func);
1255 m_freem(struct mbuf *m)
1264 m_extadd(struct mbuf *m, caddr_t buf, u_int size, void (*reff)(void *),
1265 void (*freef)(void *), void *arg)
1267 m->m_ext.ext_arg = arg;
1268 m->m_ext.ext_buf = buf;
1269 m->m_ext.ext_ref = reff;
1270 m->m_ext.ext_free = freef;
1271 m->m_ext.ext_size = size;
1274 m->m_flags |= M_EXT;
1278 * mbuf utility routines
1282 * Lesser-used path for M_PREPEND: allocate new mbuf to prepend to chain and
1286 m_prepend(struct mbuf *m, int len, int how)
1290 if (m->m_flags & M_PKTHDR)
1291 mn = m_gethdr(how, m->m_type);
1293 mn = m_get(how, m->m_type);
1298 if (m->m_flags & M_PKTHDR)
1299 M_MOVE_PKTHDR(mn, m);
1309 * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
1310 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf.
1311 * The wait parameter is a choice of MB_WAIT/MB_DONTWAIT from caller.
1312 * Note that the copy is read-only, because clusters are not copied,
1313 * only their reference counts are incremented.
1316 m_copym(const struct mbuf *m, int off0, int len, int wait)
1318 struct mbuf *n, **np;
1323 KASSERT(off >= 0, ("m_copym, negative off %d", off));
1324 KASSERT(len >= 0, ("m_copym, negative len %d", len));
1325 if (off == 0 && (m->m_flags & M_PKTHDR))
1328 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain"));
1338 KASSERT(len == M_COPYALL,
1339 ("m_copym, length > size of mbuf chain"));
1343 * Because we are sharing any cluster attachment below,
1344 * be sure to get an mbuf that does not have a cluster
1345 * associated with it.
1348 n = m_gethdr(wait, m->m_type);
1350 n = m_get(wait, m->m_type);
1355 if (!m_dup_pkthdr(n, m, wait))
1357 if (len == M_COPYALL)
1358 n->m_pkthdr.len -= off0;
1360 n->m_pkthdr.len = len;
1363 n->m_len = min(len, m->m_len - off);
1364 if (m->m_flags & M_EXT) {
1365 KKASSERT((n->m_flags & M_EXT) == 0);
1366 n->m_data = m->m_data + off;
1367 m->m_ext.ext_ref(m->m_ext.ext_arg);
1368 n->m_ext = m->m_ext;
1369 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER);
1371 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
1372 (unsigned)n->m_len);
1374 if (len != M_COPYALL)
1381 ++mbstat[mycpu->gd_cpuid].m_mcfail;
1385 ++mbstat[mycpu->gd_cpuid].m_mcfail;
1390 * Copy an entire packet, including header (which must be present).
1391 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
1392 * Note that the copy is read-only, because clusters are not copied,
1393 * only their reference counts are incremented.
1394 * Preserve alignment of the first mbuf so if the creator has left
1395 * some room at the beginning (e.g. for inserting protocol headers)
1396 * the copies also have the room available.
1399 m_copypacket(struct mbuf *m, int how)
1401 struct mbuf *top, *n, *o;
1403 n = m_gethdr(how, m->m_type);
1408 if (!m_dup_pkthdr(n, m, how))
1410 n->m_len = m->m_len;
1411 if (m->m_flags & M_EXT) {
1412 KKASSERT((n->m_flags & M_EXT) == 0);
1413 n->m_data = m->m_data;
1414 m->m_ext.ext_ref(m->m_ext.ext_arg);
1415 n->m_ext = m->m_ext;
1416 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER);
1418 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat );
1419 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
1424 o = m_get(how, m->m_type);
1431 n->m_len = m->m_len;
1432 if (m->m_flags & M_EXT) {
1433 KKASSERT((n->m_flags & M_EXT) == 0);
1434 n->m_data = m->m_data;
1435 m->m_ext.ext_ref(m->m_ext.ext_arg);
1436 n->m_ext = m->m_ext;
1437 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER);
1439 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
1447 ++mbstat[mycpu->gd_cpuid].m_mcfail;
1452 * Copy data from an mbuf chain starting "off" bytes from the beginning,
1453 * continuing for "len" bytes, into the indicated buffer.
1456 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp)
1460 KASSERT(off >= 0, ("m_copydata, negative off %d", off));
1461 KASSERT(len >= 0, ("m_copydata, negative len %d", len));
1463 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain"));
1470 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain"));
1471 count = min(m->m_len - off, len);
1472 bcopy(mtod(m, caddr_t) + off, cp, count);
1481 * Copy a packet header mbuf chain into a completely new chain, including
1482 * copying any mbuf clusters. Use this instead of m_copypacket() when
1483 * you need a writable copy of an mbuf chain.
1486 m_dup(struct mbuf *m, int how)
1488 struct mbuf **p, *top = NULL;
1489 int remain, moff, nsize;
1494 KASSERT((m->m_flags & M_PKTHDR) != 0, ("%s: !PKTHDR", __func__));
1496 /* While there's more data, get a new mbuf, tack it on, and fill it */
1497 remain = m->m_pkthdr.len;
1500 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */
1503 /* Get the next new mbuf */
1504 n = m_getl(remain, how, m->m_type, top == NULL ? M_PKTHDR : 0,
1509 if (!m_dup_pkthdr(n, m, how))
1512 /* Link it into the new chain */
1516 /* Copy data from original mbuf(s) into new mbuf */
1518 while (n->m_len < nsize && m != NULL) {
1519 int chunk = min(nsize - n->m_len, m->m_len - moff);
1521 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk);
1525 if (moff == m->m_len) {
1531 /* Check correct total mbuf length */
1532 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL),
1533 ("%s: bogus m_pkthdr.len", __func__));
1540 ++mbstat[mycpu->gd_cpuid].m_mcfail;
1545 * Copy the non-packet mbuf data chain into a new set of mbufs, including
1546 * copying any mbuf clusters. This is typically used to realign a data
1547 * chain by nfs_realign().
1549 * The original chain is left intact. how should be MB_WAIT or MB_DONTWAIT
1550 * and NULL can be returned if MB_DONTWAIT is passed.
1552 * Be careful to use cluster mbufs, a large mbuf chain converted to non
1553 * cluster mbufs can exhaust our supply of mbufs.
1556 m_dup_data(struct mbuf *m, int how)
1558 struct mbuf **p, *n, *top = NULL;
1559 int mlen, moff, chunk, gsize, nsize;
1568 * Optimize the mbuf allocation but do not get too carried away.
1570 if (m->m_next || m->m_len > MLEN)
1571 if (m->m_flags & M_EXT && m->m_ext.ext_size == MCLBYTES)
1574 gsize = MJUMPAGESIZE;
1584 * Scan the mbuf chain until nothing is left, the new mbuf chain
1585 * will be allocated on the fly as needed.
1592 KKASSERT(m->m_type == MT_DATA);
1594 n = m_getl(gsize, how, MT_DATA, 0, &nsize);
1601 chunk = imin(mlen, nsize);
1602 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk);
1617 ++mbstat[mycpu->gd_cpuid].m_mcfail;
1622 * Concatenate mbuf chain n to m.
1623 * Both chains must be of the same type (e.g. MT_DATA).
1624 * Any m_pkthdr is not updated.
1627 m_cat(struct mbuf *m, struct mbuf *n)
1631 if (m->m_flags & M_EXT ||
1632 m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) {
1633 /* just join the two chains */
1637 /* splat the data from one into the other */
1638 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1640 m->m_len += n->m_len;
1646 m_adj(struct mbuf *mp, int req_len)
1652 if ((m = mp) == NULL)
1658 while (m != NULL && len > 0) {
1659 if (m->m_len <= len) {
1670 if (mp->m_flags & M_PKTHDR)
1671 m->m_pkthdr.len -= (req_len - len);
1674 * Trim from tail. Scan the mbuf chain,
1675 * calculating its length and finding the last mbuf.
1676 * If the adjustment only affects this mbuf, then just
1677 * adjust and return. Otherwise, rescan and truncate
1678 * after the remaining size.
1684 if (m->m_next == NULL)
1688 if (m->m_len >= len) {
1690 if (mp->m_flags & M_PKTHDR)
1691 mp->m_pkthdr.len -= len;
1698 * Correct length for chain is "count".
1699 * Find the mbuf with last data, adjust its length,
1700 * and toss data from remaining mbufs on chain.
1703 if (m->m_flags & M_PKTHDR)
1704 m->m_pkthdr.len = count;
1705 for (; m; m = m->m_next) {
1706 if (m->m_len >= count) {
1713 (m = m->m_next) ->m_len = 0;
1718 * Set the m_data pointer of a newly-allocated mbuf
1719 * to place an object of the specified size at the
1720 * end of the mbuf, longword aligned.
1723 m_align(struct mbuf *m, int len)
1727 if (m->m_flags & M_EXT)
1728 adjust = m->m_ext.ext_size - len;
1729 else if (m->m_flags & M_PKTHDR)
1730 adjust = MHLEN - len;
1732 adjust = MLEN - len;
1733 m->m_data += adjust &~ (sizeof(long)-1);
1737 * Create a writable copy of the mbuf chain. While doing this
1738 * we compact the chain with a goal of producing a chain with
1739 * at most two mbufs. The second mbuf in this chain is likely
1740 * to be a cluster. The primary purpose of this work is to create
1741 * a writable packet for encryption, compression, etc. The
1742 * secondary goal is to linearize the data so the data can be
1743 * passed to crypto hardware in the most efficient manner possible.
1746 m_unshare(struct mbuf *m0, int how)
1748 struct mbuf *m, *mprev;
1749 struct mbuf *n, *mfirst, *mlast;
1753 for (m = m0; m != NULL; m = mprev->m_next) {
1755 * Regular mbufs are ignored unless there's a cluster
1756 * in front of it that we can use to coalesce. We do
1757 * the latter mainly so later clusters can be coalesced
1758 * also w/o having to handle them specially (i.e. convert
1759 * mbuf+cluster -> cluster). This optimization is heavily
1760 * influenced by the assumption that we're running over
1761 * Ethernet where MCLBYTES is large enough that the max
1762 * packet size will permit lots of coalescing into a
1763 * single cluster. This in turn permits efficient
1764 * crypto operations, especially when using hardware.
1766 if ((m->m_flags & M_EXT) == 0) {
1767 if (mprev && (mprev->m_flags & M_EXT) &&
1768 m->m_len <= M_TRAILINGSPACE(mprev)) {
1769 /* XXX: this ignores mbuf types */
1770 memcpy(mtod(mprev, caddr_t) + mprev->m_len,
1771 mtod(m, caddr_t), m->m_len);
1772 mprev->m_len += m->m_len;
1773 mprev->m_next = m->m_next; /* unlink from chain */
1774 m_free(m); /* reclaim mbuf */
1781 * Writable mbufs are left alone (for now).
1783 if (M_WRITABLE(m)) {
1789 * Not writable, replace with a copy or coalesce with
1790 * the previous mbuf if possible (since we have to copy
1791 * it anyway, we try to reduce the number of mbufs and
1792 * clusters so that future work is easier).
1794 KASSERT(m->m_flags & M_EXT, ("m_flags 0x%x", m->m_flags));
1795 /* NB: we only coalesce into a cluster or larger */
1796 if (mprev != NULL && (mprev->m_flags & M_EXT) &&
1797 m->m_len <= M_TRAILINGSPACE(mprev)) {
1798 /* XXX: this ignores mbuf types */
1799 memcpy(mtod(mprev, caddr_t) + mprev->m_len,
1800 mtod(m, caddr_t), m->m_len);
1801 mprev->m_len += m->m_len;
1802 mprev->m_next = m->m_next; /* unlink from chain */
1803 m_free(m); /* reclaim mbuf */
1808 * Allocate new space to hold the copy...
1810 /* XXX why can M_PKTHDR be set past the first mbuf? */
1811 if (mprev == NULL && (m->m_flags & M_PKTHDR)) {
1813 * NB: if a packet header is present we must
1814 * allocate the mbuf separately from any cluster
1815 * because M_MOVE_PKTHDR will smash the data
1816 * pointer and drop the M_EXT marker.
1818 MGETHDR(n, how, m->m_type);
1823 M_MOVE_PKTHDR(n, m);
1825 if ((n->m_flags & M_EXT) == 0) {
1831 n = m_getcl(how, m->m_type, m->m_flags);
1838 * ... and copy the data. We deal with jumbo mbufs
1839 * (i.e. m_len > MCLBYTES) by splitting them into
1840 * clusters. We could just malloc a buffer and make
1841 * it external but too many device drivers don't know
1842 * how to break up the non-contiguous memory when
1850 int cc = min(len, MCLBYTES);
1851 memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, cc);
1862 n = m_getcl(how, m->m_type, m->m_flags);
1869 n->m_next = m->m_next;
1871 m0 = mfirst; /* new head of chain */
1873 mprev->m_next = mfirst; /* replace old mbuf */
1874 m_free(m); /* release old mbuf */
1881 * Rearrange an mbuf chain so that len bytes are contiguous
1882 * and in the data area of an mbuf (so that mtod will work for a structure
1883 * of size len). Returns the resulting mbuf chain on success, frees it and
1884 * returns null on failure. If there is room, it will add up to
1885 * max_protohdr-len extra bytes to the contiguous region in an attempt to
1886 * avoid being called next time.
1889 m_pullup(struct mbuf *n, int len)
1896 * If first mbuf has no cluster, and has room for len bytes
1897 * without shifting current data, pullup into it,
1898 * otherwise allocate a new mbuf to prepend to the chain.
1900 if (!(n->m_flags & M_EXT) &&
1901 n->m_data + len < &n->m_dat[MLEN] &&
1903 if (n->m_len >= len)
1911 if (n->m_flags & M_PKTHDR)
1912 m = m_gethdr(MB_DONTWAIT, n->m_type);
1914 m = m_get(MB_DONTWAIT, n->m_type);
1918 if (n->m_flags & M_PKTHDR)
1919 M_MOVE_PKTHDR(m, n);
1921 space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
1923 count = min(min(max(len, max_protohdr), space), n->m_len);
1924 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1934 } while (len > 0 && n);
1943 ++mbstat[mycpu->gd_cpuid].m_mcfail;
1948 * Partition an mbuf chain in two pieces, returning the tail --
1949 * all but the first len0 bytes. In case of failure, it returns NULL and
1950 * attempts to restore the chain to its original state.
1952 * Note that the resulting mbufs might be read-only, because the new
1953 * mbuf can end up sharing an mbuf cluster with the original mbuf if
1954 * the "breaking point" happens to lie within a cluster mbuf. Use the
1955 * M_WRITABLE() macro to check for this case.
1958 m_split(struct mbuf *m0, int len0, int wait)
1961 unsigned len = len0, remain;
1963 for (m = m0; m && len > m->m_len; m = m->m_next)
1967 remain = m->m_len - len;
1968 if (m0->m_flags & M_PKTHDR) {
1969 n = m_gethdr(wait, m0->m_type);
1972 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
1973 n->m_pkthdr.len = m0->m_pkthdr.len - len0;
1974 m0->m_pkthdr.len = len0;
1975 if (m->m_flags & M_EXT)
1977 if (remain > MHLEN) {
1978 /* m can't be the lead packet */
1980 n->m_next = m_split(m, len, wait);
1981 if (n->m_next == NULL) {
1989 MH_ALIGN(n, remain);
1990 } else if (remain == 0) {
1995 n = m_get(wait, m->m_type);
2001 if (m->m_flags & M_EXT) {
2002 KKASSERT((n->m_flags & M_EXT) == 0);
2003 n->m_data = m->m_data + len;
2004 m->m_ext.ext_ref(m->m_ext.ext_arg);
2005 n->m_ext = m->m_ext;
2006 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER);
2008 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain);
2012 n->m_next = m->m_next;
2018 * Routine to copy from device local memory into mbufs.
2019 * Note: "offset" is ill-defined and always called as 0, so ignore it.
2022 m_devget(char *buf, int len, int offset, struct ifnet *ifp,
2023 void (*copy)(volatile const void *from, volatile void *to, size_t length))
2025 struct mbuf *m, *mfirst = NULL, **mtail;
2034 m = m_getl(len, MB_DONTWAIT, MT_DATA, flags, &nsize);
2039 m->m_len = min(len, nsize);
2041 if (flags & M_PKTHDR) {
2042 if (len + max_linkhdr <= nsize)
2043 m->m_data += max_linkhdr;
2044 m->m_pkthdr.rcvif = ifp;
2045 m->m_pkthdr.len = len;
2049 copy(buf, m->m_data, (unsigned)m->m_len);
2060 * Routine to pad mbuf to the specified length 'padto'.
2063 m_devpad(struct mbuf *m, int padto)
2065 struct mbuf *last = NULL;
2068 if (padto <= m->m_pkthdr.len)
2071 padlen = padto - m->m_pkthdr.len;
2073 /* if there's only the packet-header and we can pad there, use it. */
2074 if (m->m_pkthdr.len == m->m_len && M_TRAILINGSPACE(m) >= padlen) {
2078 * Walk packet chain to find last mbuf. We will either
2079 * pad there, or append a new mbuf and pad it
2081 for (last = m; last->m_next != NULL; last = last->m_next)
2084 /* `last' now points to last in chain. */
2085 if (M_TRAILINGSPACE(last) < padlen) {
2088 /* Allocate new empty mbuf, pad it. Compact later. */
2089 MGET(n, MB_DONTWAIT, MT_DATA);
2097 KKASSERT(M_TRAILINGSPACE(last) >= padlen);
2098 KKASSERT(M_WRITABLE(last));
2100 /* Now zero the pad area */
2101 bzero(mtod(last, char *) + last->m_len, padlen);
2102 last->m_len += padlen;
2103 m->m_pkthdr.len += padlen;
2108 * Copy data from a buffer back into the indicated mbuf chain,
2109 * starting "off" bytes from the beginning, extending the mbuf
2110 * chain if necessary.
2113 m_copyback(struct mbuf *m0, int off, int len, caddr_t cp)
2116 struct mbuf *m = m0, *n;
2121 while (off > (mlen = m->m_len)) {
2124 if (m->m_next == NULL) {
2125 n = m_getclr(MB_DONTWAIT, m->m_type);
2128 n->m_len = min(MLEN, len + off);
2134 mlen = min (m->m_len - off, len);
2135 bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen);
2143 if (m->m_next == NULL) {
2144 n = m_get(MB_DONTWAIT, m->m_type);
2147 n->m_len = min(MLEN, len);
2152 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
2153 m->m_pkthdr.len = totlen;
2157 * Append the specified data to the indicated mbuf chain,
2158 * Extend the mbuf chain if the new data does not fit in
2161 * Return 1 if able to complete the job; otherwise 0.
2164 m_append(struct mbuf *m0, int len, c_caddr_t cp)
2167 int remainder, space;
2169 for (m = m0; m->m_next != NULL; m = m->m_next)
2172 space = M_TRAILINGSPACE(m);
2175 * Copy into available space.
2177 if (space > remainder)
2179 bcopy(cp, mtod(m, caddr_t) + m->m_len, space);
2181 cp += space, remainder -= space;
2183 while (remainder > 0) {
2185 * Allocate a new mbuf; could check space
2186 * and allocate a cluster instead.
2188 n = m_get(MB_DONTWAIT, m->m_type);
2191 n->m_len = min(MLEN, remainder);
2192 bcopy(cp, mtod(n, caddr_t), n->m_len);
2193 cp += n->m_len, remainder -= n->m_len;
2197 if (m0->m_flags & M_PKTHDR)
2198 m0->m_pkthdr.len += len - remainder;
2199 return (remainder == 0);
2203 * Apply function f to the data in an mbuf chain starting "off" bytes from
2204 * the beginning, continuing for "len" bytes.
2207 m_apply(struct mbuf *m, int off, int len,
2208 int (*f)(void *, void *, u_int), void *arg)
2213 KASSERT(off >= 0, ("m_apply, negative off %d", off));
2214 KASSERT(len >= 0, ("m_apply, negative len %d", len));
2216 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
2223 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
2224 count = min(m->m_len - off, len);
2225 rval = (*f)(arg, mtod(m, caddr_t) + off, count);
2236 * Return a pointer to mbuf/offset of location in mbuf chain.
2239 m_getptr(struct mbuf *m, int loc, int *off)
2243 /* Normal end of search. */
2244 if (m->m_len > loc) {
2249 if (m->m_next == NULL) {
2251 /* Point at the end of valid data. */
2264 m_print(const struct mbuf *m)
2267 const struct mbuf *m2;
2270 len = m->m_pkthdr.len;
2272 hexstr = kmalloc(HEX_NCPYLEN(len), M_TEMP, M_ZERO | M_WAITOK);
2274 kprintf("%p %s\n", m2, hexncpy(m2->m_data, m2->m_len, hexstr,
2275 HEX_NCPYLEN(m2->m_len), "-"));
2279 kfree(hexstr, M_TEMP);
2284 * "Move" mbuf pkthdr from "from" to "to".
2285 * "from" must have M_PKTHDR set, and "to" must be empty.
2288 m_move_pkthdr(struct mbuf *to, struct mbuf *from)
2290 KASSERT((to->m_flags & M_PKTHDR), ("m_move_pkthdr: not packet header"));
2292 to->m_flags |= from->m_flags & M_COPYFLAGS;
2293 to->m_pkthdr = from->m_pkthdr; /* especially tags */
2294 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */
2298 * Duplicate "from"'s mbuf pkthdr in "to".
2299 * "from" must have M_PKTHDR set, and "to" must be empty.
2300 * In particular, this does a deep copy of the packet tags.
2303 m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how)
2305 KASSERT((to->m_flags & M_PKTHDR), ("m_dup_pkthdr: not packet header"));
2307 to->m_flags = (from->m_flags & M_COPYFLAGS) |
2308 (to->m_flags & ~M_COPYFLAGS);
2309 to->m_pkthdr = from->m_pkthdr;
2310 SLIST_INIT(&to->m_pkthdr.tags);
2311 return (m_tag_copy_chain(to, from, how));
2315 * Defragment a mbuf chain, returning the shortest possible
2316 * chain of mbufs and clusters. If allocation fails and
2317 * this cannot be completed, NULL will be returned, but
2318 * the passed in chain will be unchanged. Upon success,
2319 * the original chain will be freed, and the new chain
2322 * If a non-packet header is passed in, the original
2323 * mbuf (chain?) will be returned unharmed.
2325 * m_defrag_nofree doesn't free the passed in mbuf.
2328 m_defrag(struct mbuf *m0, int how)
2332 if ((m_new = m_defrag_nofree(m0, how)) == NULL)
2340 m_defrag_nofree(struct mbuf *m0, int how)
2342 struct mbuf *m_new = NULL, *m_final = NULL;
2343 int progress = 0, length, nsize;
2345 if (!(m0->m_flags & M_PKTHDR))
2348 #ifdef MBUF_STRESS_TEST
2349 if (m_defragrandomfailures) {
2350 int temp = karc4random() & 0xff;
2356 m_final = m_getl(m0->m_pkthdr.len, how, MT_DATA, M_PKTHDR, &nsize);
2357 if (m_final == NULL)
2359 m_final->m_len = 0; /* in case m0->m_pkthdr.len is zero */
2361 if (m_dup_pkthdr(m_final, m0, how) == 0)
2366 while (progress < m0->m_pkthdr.len) {
2367 length = m0->m_pkthdr.len - progress;
2368 if (length > MCLBYTES)
2371 if (m_new == NULL) {
2372 m_new = m_getl(length, how, MT_DATA, 0, &nsize);
2377 m_copydata(m0, progress, length, mtod(m_new, caddr_t));
2379 m_new->m_len = length;
2380 if (m_new != m_final)
2381 m_cat(m_final, m_new);
2384 if (m0->m_next == NULL)
2387 m_defragbytes += m_final->m_pkthdr.len;
2398 * Move data from uio into mbufs.
2401 m_uiomove(struct uio *uio)
2403 struct mbuf *m; /* current working mbuf */
2404 struct mbuf *head = NULL; /* result mbuf chain */
2405 struct mbuf **mp = &head;
2406 int flags = M_PKTHDR;
2412 if (uio->uio_resid > INT_MAX)
2415 resid = (int)uio->uio_resid;
2416 m = m_getl(resid, MB_WAIT, MT_DATA, flags, &nsize);
2418 m->m_pkthdr.len = 0;
2419 /* Leave room for protocol headers. */
2424 m->m_len = imin(nsize, resid);
2425 error = uiomove(mtod(m, caddr_t), m->m_len, uio);
2432 head->m_pkthdr.len += m->m_len;
2433 } while (uio->uio_resid > 0);
2443 m_last(struct mbuf *m)
2451 * Return the number of bytes in an mbuf chain.
2452 * If lastm is not NULL, also return the last mbuf.
2455 m_lengthm(struct mbuf *m, struct mbuf **lastm)
2458 struct mbuf *prev = m;
2471 * Like m_lengthm(), except also keep track of mbuf usage.
2474 m_countm(struct mbuf *m, struct mbuf **lastm, u_int *pmbcnt)
2476 u_int len = 0, mbcnt = 0;
2477 struct mbuf *prev = m;
2482 if (m->m_flags & M_EXT)
2483 mbcnt += m->m_ext.ext_size;