Register keyword removal
[dragonfly.git] / sys / kern / uipc_mbuf.c
CommitLineData
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1/*
2 * Copyright (c) 1982, 1986, 1988, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94
34 * $FreeBSD: src/sys/kern/uipc_mbuf.c,v 1.51.2.24 2003/04/15 06:59:29 silby Exp $
f15db79e 35 * $DragonFly: src/sys/kern/uipc_mbuf.c,v 1.9 2003/07/23 02:30:20 dillon Exp $
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36 */
37
38#include "opt_param.h"
39#include "opt_mbuf_stress_test.h"
40#include <sys/param.h>
41#include <sys/systm.h>
42#include <sys/malloc.h>
43#include <sys/mbuf.h>
44#include <sys/kernel.h>
45#include <sys/sysctl.h>
46#include <sys/domain.h>
47#include <sys/protosw.h>
ef0fdad1 48#include <sys/thread.h>
a2a5ad0d 49#include <sys/globaldata.h>
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50
51#include <vm/vm.h>
52#include <vm/vm_kern.h>
53#include <vm/vm_extern.h>
54
55#ifdef INVARIANTS
56#include <machine/cpu.h>
57#endif
58
59static void mbinit __P((void *));
60SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL)
61
62struct mbuf *mbutl;
63char *mclrefcnt;
64struct mbstat mbstat;
65u_long mbtypes[MT_NTYPES];
66struct mbuf *mmbfree;
67union mcluster *mclfree;
68int max_linkhdr;
69int max_protohdr;
70int max_hdr;
71int max_datalen;
72int m_defragpackets;
73int m_defragbytes;
74int m_defraguseless;
75int m_defragfailure;
76#ifdef MBUF_STRESS_TEST
77int m_defragrandomfailures;
78#endif
79
80int nmbclusters;
81int nmbufs;
82u_int m_mballoc_wid = 0;
83u_int m_clalloc_wid = 0;
84
85SYSCTL_DECL(_kern_ipc);
86SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW,
87 &max_linkhdr, 0, "");
88SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW,
89 &max_protohdr, 0, "");
90SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0, "");
91SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW,
92 &max_datalen, 0, "");
93SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_wait, CTLFLAG_RW,
94 &mbuf_wait, 0, "");
95SYSCTL_STRUCT(_kern_ipc, KIPC_MBSTAT, mbstat, CTLFLAG_RW, &mbstat, mbstat, "");
96SYSCTL_OPAQUE(_kern_ipc, OID_AUTO, mbtypes, CTLFLAG_RD, mbtypes,
97 sizeof(mbtypes), "LU", "");
98SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters, CTLFLAG_RD,
99 &nmbclusters, 0, "Maximum number of mbuf clusters available");
100SYSCTL_INT(_kern_ipc, OID_AUTO, nmbufs, CTLFLAG_RD, &nmbufs, 0,
101 "Maximum number of mbufs available");
102SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD,
103 &m_defragpackets, 0, "");
104SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD,
105 &m_defragbytes, 0, "");
106SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD,
107 &m_defraguseless, 0, "");
108SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD,
109 &m_defragfailure, 0, "");
110#ifdef MBUF_STRESS_TEST
111SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW,
112 &m_defragrandomfailures, 0, "");
113#endif
114
115static void m_reclaim __P((void));
116
117#ifndef NMBCLUSTERS
118#define NMBCLUSTERS (512 + maxusers * 16)
119#endif
120#ifndef NMBUFS
121#define NMBUFS (nmbclusters * 4)
122#endif
123
124/*
125 * Perform sanity checks of tunables declared above.
126 */
127static void
128tunable_mbinit(void *dummy)
129{
130
131 /*
132 * This has to be done before VM init.
133 */
134 nmbclusters = NMBCLUSTERS;
135 TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
136 nmbufs = NMBUFS;
137 TUNABLE_INT_FETCH("kern.ipc.nmbufs", &nmbufs);
138 /* Sanity checks */
139 if (nmbufs < nmbclusters * 2)
140 nmbufs = nmbclusters * 2;
141
142 return;
143}
144SYSINIT(tunable_mbinit, SI_SUB_TUNABLES, SI_ORDER_ANY, tunable_mbinit, NULL);
145
146/* "number of clusters of pages" */
147#define NCL_INIT 1
148
149#define NMB_INIT 16
150
151/* ARGSUSED*/
152static void
153mbinit(dummy)
154 void *dummy;
155{
156 int s;
157
158 mmbfree = NULL; mclfree = NULL;
159 mbstat.m_msize = MSIZE;
160 mbstat.m_mclbytes = MCLBYTES;
161 mbstat.m_minclsize = MINCLSIZE;
162 mbstat.m_mlen = MLEN;
163 mbstat.m_mhlen = MHLEN;
164
165 s = splimp();
166 if (m_mballoc(NMB_INIT, M_DONTWAIT) == 0)
167 goto bad;
168#if MCLBYTES <= PAGE_SIZE
169 if (m_clalloc(NCL_INIT, M_DONTWAIT) == 0)
170 goto bad;
171#else
172 /* It's OK to call contigmalloc in this context. */
173 if (m_clalloc(16, M_WAIT) == 0)
174 goto bad;
175#endif
176 splx(s);
177 return;
178bad:
179 panic("mbinit");
180}
181
182/*
183 * Allocate at least nmb mbufs and place on mbuf free list.
184 * Must be called at splimp.
185 */
186/* ARGSUSED */
187int
188m_mballoc(nmb, how)
189 register int nmb;
190 int how;
191{
192 register caddr_t p;
193 register int i;
194 int nbytes;
195
196 /*
197 * If we've hit the mbuf limit, stop allocating from mb_map,
198 * (or trying to) in order to avoid dipping into the section of
199 * mb_map which we've "reserved" for clusters.
200 */
201 if ((nmb + mbstat.m_mbufs) > nmbufs)
202 return (0);
203
204 /*
205 * Once we run out of map space, it will be impossible to get
206 * any more (nothing is ever freed back to the map)
207 * -- however you are not dead as m_reclaim might
208 * still be able to free a substantial amount of space.
209 *
210 * XXX Furthermore, we can also work with "recycled" mbufs (when
211 * we're calling with M_WAIT the sleep procedure will be woken
212 * up when an mbuf is freed. See m_mballoc_wait()).
213 */
214 if (mb_map_full)
215 return (0);
216
217 nbytes = round_page(nmb * MSIZE);
218 p = (caddr_t)kmem_malloc(mb_map, nbytes, M_NOWAIT);
219 if (p == 0 && how == M_WAIT) {
220 mbstat.m_wait++;
221 p = (caddr_t)kmem_malloc(mb_map, nbytes, M_WAITOK);
222 }
223
224 /*
225 * Either the map is now full, or `how' is M_NOWAIT and there
226 * are no pages left.
227 */
228 if (p == NULL)
229 return (0);
230
231 nmb = nbytes / MSIZE;
232 for (i = 0; i < nmb; i++) {
233 ((struct mbuf *)p)->m_next = mmbfree;
234 mmbfree = (struct mbuf *)p;
235 p += MSIZE;
236 }
237 mbstat.m_mbufs += nmb;
238 mbtypes[MT_FREE] += nmb;
239 return (1);
240}
241
242/*
243 * Once the mb_map has been exhausted and if the call to the allocation macros
244 * (or, in some cases, functions) is with M_WAIT, then it is necessary to rely
245 * solely on reclaimed mbufs. Here we wait for an mbuf to be freed for a
246 * designated (mbuf_wait) time.
247 */
248struct mbuf *
249m_mballoc_wait(int caller, int type)
250{
251 struct mbuf *p;
252 int s;
253
254 s = splimp();
255 m_mballoc_wid++;
377d4740 256 if ((tsleep(&m_mballoc_wid, 0, "mballc", mbuf_wait)) == EWOULDBLOCK)
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257 m_mballoc_wid--;
258 splx(s);
259
260 /*
261 * Now that we (think) that we've got something, we will redo an
262 * MGET, but avoid getting into another instance of m_mballoc_wait()
263 * XXX: We retry to fetch _even_ if the sleep timed out. This is left
264 * this way, purposely, in the [unlikely] case that an mbuf was
265 * freed but the sleep was not awakened in time.
266 */
267 p = NULL;
268 switch (caller) {
269 case MGET_C:
270 MGET(p, M_DONTWAIT, type);
271 break;
272 case MGETHDR_C:
273 MGETHDR(p, M_DONTWAIT, type);
274 break;
275 default:
276 panic("m_mballoc_wait: invalid caller (%d)", caller);
277 }
278
279 s = splimp();
280 if (p != NULL) { /* We waited and got something... */
281 mbstat.m_wait++;
282 /* Wake up another if we have more free. */
283 if (mmbfree != NULL)
284 MMBWAKEUP();
285 }
286 splx(s);
287 return (p);
288}
289
290#if MCLBYTES > PAGE_SIZE
291static int i_want_my_mcl;
292
293static void
294kproc_mclalloc(void)
295{
296 int status;
297
298 while (1) {
377d4740 299 tsleep(&i_want_my_mcl, 0, "mclalloc", 0);
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300
301 for (; i_want_my_mcl; i_want_my_mcl--) {
302 if (m_clalloc(1, M_WAIT) == 0)
303 printf("m_clalloc failed even in process context!\n");
304 }
305 }
306}
307
bc6dffab 308static struct thread *mclallocthread;
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309static struct kproc_desc mclalloc_kp = {
310 "mclalloc",
311 kproc_mclalloc,
bc6dffab 312 &mclallocthread
984263bc 313};
bc6dffab 314SYSINIT(mclallocthread, SI_SUB_KTHREAD_UPDATE, SI_ORDER_ANY, kproc_start,
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315 &mclalloc_kp);
316#endif
317
318/*
319 * Allocate some number of mbuf clusters
320 * and place on cluster free list.
321 * Must be called at splimp.
322 */
323/* ARGSUSED */
324int
325m_clalloc(ncl, how)
326 register int ncl;
327 int how;
328{
329 register caddr_t p;
330 register int i;
331 int npg;
332
333 /*
334 * If we've hit the mcluster number limit, stop allocating from
335 * mb_map, (or trying to) in order to avoid dipping into the section
336 * of mb_map which we've "reserved" for mbufs.
337 */
338 if ((ncl + mbstat.m_clusters) > nmbclusters)
339 goto m_clalloc_fail;
340
341 /*
342 * Once we run out of map space, it will be impossible
343 * to get any more (nothing is ever freed back to the
344 * map). From this point on, we solely rely on freed
345 * mclusters.
346 */
347 if (mb_map_full)
348 goto m_clalloc_fail;
349
350#if MCLBYTES > PAGE_SIZE
351 if (how != M_WAIT) {
352 i_want_my_mcl += ncl;
353 wakeup(&i_want_my_mcl);
354 mbstat.m_wait++;
355 p = 0;
356 } else {
357 p = contigmalloc1(MCLBYTES * ncl, M_DEVBUF, M_WAITOK, 0ul,
358 ~0ul, PAGE_SIZE, 0, mb_map);
359 }
360#else
361 npg = ncl;
362 p = (caddr_t)kmem_malloc(mb_map, ctob(npg),
363 how != M_WAIT ? M_NOWAIT : M_WAITOK);
364 ncl = ncl * PAGE_SIZE / MCLBYTES;
365#endif
366 /*
367 * Either the map is now full, or `how' is M_NOWAIT and there
368 * are no pages left.
369 */
370 if (p == NULL) {
371 static int last_report ; /* when we did that (in ticks) */
372m_clalloc_fail:
373 mbstat.m_drops++;
374 if (ticks < last_report || (ticks - last_report) >= hz) {
375 last_report = ticks;
376 printf("All mbuf clusters exhausted, please see tuning(7).\n");
377 }
378 return (0);
379 }
380
381 for (i = 0; i < ncl; i++) {
382 ((union mcluster *)p)->mcl_next = mclfree;
383 mclfree = (union mcluster *)p;
384 p += MCLBYTES;
385 mbstat.m_clfree++;
386 }
387 mbstat.m_clusters += ncl;
388 return (1);
389}
390
391/*
392 * Once the mb_map submap has been exhausted and the allocation is called with
393 * M_WAIT, we rely on the mclfree union pointers. If nothing is free, we will
394 * sleep for a designated amount of time (mbuf_wait) or until we're woken up
395 * due to sudden mcluster availability.
396 */
397caddr_t
398m_clalloc_wait(void)
399{
400 caddr_t p;
401 int s;
402
403#ifdef __i386__
404 /* If in interrupt context, and INVARIANTS, maintain sanity and die. */
ef0fdad1 405 KASSERT(mycpu->gd_intr_nesting_level == 0, ("CLALLOC: CANNOT WAIT IN INTERRUPT"));
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406#endif
407
408 /* Sleep until something's available or until we expire. */
409 m_clalloc_wid++;
377d4740 410 if ((tsleep(&m_clalloc_wid, 0, "mclalc", mbuf_wait)) == EWOULDBLOCK)
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411 m_clalloc_wid--;
412
413 /*
414 * Now that we (think) that we've got something, we will redo and
415 * MGET, but avoid getting into another instance of m_clalloc_wait()
416 */
b6650ec0 417 p = m_mclalloc(M_DONTWAIT);
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418
419 s = splimp();
420 if (p != NULL) { /* We waited and got something... */
421 mbstat.m_wait++;
422 /* Wake up another if we have more free. */
423 if (mclfree != NULL)
424 MCLWAKEUP();
425 }
426
427 splx(s);
428 return (p);
429}
430
431/*
432 * When MGET fails, ask protocols to free space when short of memory,
433 * then re-attempt to allocate an mbuf.
434 */
435struct mbuf *
436m_retry(i, t)
437 int i, t;
438{
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439 struct mbuf *m;
440 int ms;
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441
442 /*
443 * Must only do the reclaim if not in an interrupt context.
444 */
445 if (i == M_WAIT) {
446#ifdef __i386__
ef0fdad1 447 KASSERT(mycpu->gd_intr_nesting_level == 0,
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448 ("MBALLOC: CANNOT WAIT IN INTERRUPT"));
449#endif
450 m_reclaim();
451 }
452
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453 ms = splimp();
454 if (mmbfree == NULL)
455 (void)m_mballoc(1, i);
456 m = mmbfree;
457 if (m != NULL) {
458 mmbfree = m->m_next;
459 mbtypes[MT_FREE]--;
460 m->m_type = t;
461 mbtypes[t]++;
462 m->m_next = NULL;
463 m->m_nextpkt = NULL;
464 m->m_data = m->m_dat;
465 m->m_flags = 0;
466 splx(ms);
984263bc 467 mbstat.m_wait++;
12496bdf 468 } else {
984263bc 469 static int last_report ; /* when we did that (in ticks) */
377d4740 470
12496bdf 471 splx(ms);
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472 mbstat.m_drops++;
473 if (ticks < last_report || (ticks - last_report) >= hz) {
474 last_report = ticks;
475 printf("All mbufs exhausted, please see tuning(7).\n");
476 }
477 }
478
479 return (m);
480}
481
482/*
483 * As above; retry an MGETHDR.
484 */
485struct mbuf *
486m_retryhdr(i, t)
487 int i, t;
488{
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489 struct mbuf *m;
490 int ms;
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491
492 /*
493 * Must only do the reclaim if not in an interrupt context.
494 */
495 if (i == M_WAIT) {
496#ifdef __i386__
ef0fdad1 497 KASSERT(mycpu->gd_intr_nesting_level == 0,
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498 ("MBALLOC: CANNOT WAIT IN INTERRUPT"));
499#endif
500 m_reclaim();
501 }
502
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503 ms = splimp();
504 if (mmbfree == NULL)
505 (void)m_mballoc(1, i);
506 m = mmbfree;
507 if (m != NULL) {
508 mmbfree = m->m_next;
509 mbtypes[MT_FREE]--;
510 m->m_type = t;
511 mbtypes[t]++;
512 m->m_next = NULL;
513 m->m_nextpkt = NULL;
514 m->m_data = m->m_pktdat;
515 m->m_flags = M_PKTHDR;
516 m->m_pkthdr.rcvif = NULL;
517 SLIST_INIT(&m->m_pkthdr.tags);
518 m->m_pkthdr.csum_flags = 0;
519 splx(ms);
984263bc 520 mbstat.m_wait++;
12496bdf 521 } else {
984263bc 522 static int last_report ; /* when we did that (in ticks) */
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523
524 splx(ms);
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525 mbstat.m_drops++;
526 if (ticks < last_report || (ticks - last_report) >= hz) {
527 last_report = ticks;
528 printf("All mbufs exhausted, please see tuning(7).\n");
529 }
530 }
531
532 return (m);
533}
534
535static void
536m_reclaim()
537{
538 register struct domain *dp;
539 register struct protosw *pr;
540 int s = splimp();
541
542 for (dp = domains; dp; dp = dp->dom_next)
543 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
544 if (pr->pr_drain)
545 (*pr->pr_drain)();
546 splx(s);
547 mbstat.m_drain++;
548}
549
550/*
551 * Space allocation routines.
552 * These are also available as macros
553 * for critical paths.
554 */
555struct mbuf *
556m_get(how, type)
557 int how, type;
558{
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559 struct mbuf *m;
560 int ms;
561
562 ms = splimp();
563 if (mmbfree == NULL)
564 (void)m_mballoc(1, how);
565 m = mmbfree;
566 if (m != NULL) {
567 mmbfree = m->m_next;
568 mbtypes[MT_FREE]--;
569 m->m_type = type;
570 mbtypes[type]++;
571 m->m_next = NULL;
572 m->m_nextpkt = NULL;
573 m->m_data = m->m_dat;
574 m->m_flags = 0;
575 splx(ms);
576 } else {
577 splx(ms);
578 m = m_retry(how, type);
579 if (m == NULL && how == M_WAIT)
580 m = m_mballoc_wait(MGET_C, type);
581 }
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582 return (m);
583}
584
585struct mbuf *
586m_gethdr(how, type)
587 int how, type;
588{
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589 struct mbuf *m;
590 int ms;
591
592 ms = splimp();
593 if (mmbfree == NULL)
594 (void)m_mballoc(1, how);
595 m = mmbfree;
596 if (m != NULL) {
597 mmbfree = m->m_next;
598 mbtypes[MT_FREE]--;
599 m->m_type = type;
600 mbtypes[type]++;
601 m->m_next = NULL;
602 m->m_nextpkt = NULL;
603 m->m_data = m->m_pktdat;
604 m->m_flags = M_PKTHDR;
605 m->m_pkthdr.rcvif = NULL;
606 SLIST_INIT(&m->m_pkthdr.tags);
607 m->m_pkthdr.csum_flags = 0;
608 splx(ms);
609 } else {
610 splx(ms);
611 m = m_retryhdr(how, type);
612 if (m == NULL && how == M_WAIT)
613 m = m_mballoc_wait(MGETHDR_C, type);
614 }
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615 return (m);
616}
617
618struct mbuf *
619m_getclr(how, type)
620 int how, type;
621{
622 register struct mbuf *m;
623
624 MGET(m, how, type);
625 if (m == 0)
626 return (0);
627 bzero(mtod(m, caddr_t), MLEN);
628 return (m);
629}
630
631/*
632 * m_getcl() returns an mbuf with an attached cluster.
633 * Because many network drivers use this kind of buffers a lot, it is
634 * convenient to keep a small pool of free buffers of this kind.
635 * Even a small size such as 10 gives about 10% improvement in the
636 * forwarding rate in a bridge or router.
637 * The size of this free list is controlled by the sysctl variable
638 * mcl_pool_max. The list is populated on m_freem(), and used in
639 * m_getcl() if elements are available.
640 */
641static struct mbuf *mcl_pool;
642static int mcl_pool_now;
643static int mcl_pool_max = 0;
644
645SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_pool_max, CTLFLAG_RW, &mcl_pool_max, 0,
646 "Maximum number of mbufs+cluster in free list");
647SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_pool_now, CTLFLAG_RD, &mcl_pool_now, 0,
648 "Current number of mbufs+cluster in free list");
649
650struct mbuf *
651m_getcl(int how, short type, int flags)
652{
653 int s = splimp();
654 struct mbuf *mp;
655
656 if (flags & M_PKTHDR) {
657 if (type == MT_DATA && mcl_pool) {
658 mp = mcl_pool;
659 mcl_pool = mp->m_nextpkt;
660 mcl_pool_now--;
661 splx(s);
662 mp->m_nextpkt = NULL;
663 mp->m_data = mp->m_ext.ext_buf;
664 mp->m_flags = M_PKTHDR|M_EXT;
665 mp->m_pkthdr.rcvif = NULL;
666 mp->m_pkthdr.csum_flags = 0;
667 return mp;
668 } else
669 MGETHDR(mp, how, type);
670 } else
671 MGET(mp, how, type);
672 if (mp) {
673 MCLGET(mp, how);
674 if ( (mp->m_flags & M_EXT) == 0) {
675 m_free(mp);
676 mp = NULL;
677 }
678 }
679 splx(s);
680 return mp;
681}
682
683/*
684 * struct mbuf *
685 * m_getm(m, len, how, type)
686 *
687 * This will allocate len-worth of mbufs and/or mbuf clusters (whatever fits
688 * best) and return a pointer to the top of the allocated chain. If m is
689 * non-null, then we assume that it is a single mbuf or an mbuf chain to
690 * which we want len bytes worth of mbufs and/or clusters attached, and so
691 * if we succeed in allocating it, we will just return a pointer to m.
692 *
693 * If we happen to fail at any point during the allocation, we will free
694 * up everything we have already allocated and return NULL.
695 *
696 */
697struct mbuf *
698m_getm(struct mbuf *m, int len, int how, int type)
699{
700 struct mbuf *top, *tail, *mp, *mtail = NULL;
701
702 KASSERT(len >= 0, ("len is < 0 in m_getm"));
703
704 MGET(mp, how, type);
705 if (mp == NULL)
706 return (NULL);
707 else if (len > MINCLSIZE) {
708 MCLGET(mp, how);
709 if ((mp->m_flags & M_EXT) == 0) {
710 m_free(mp);
711 return (NULL);
712 }
713 }
714 mp->m_len = 0;
715 len -= M_TRAILINGSPACE(mp);
716
717 if (m != NULL)
718 for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next);
719 else
720 m = mp;
721
722 top = tail = mp;
723 while (len > 0) {
724 MGET(mp, how, type);
725 if (mp == NULL)
726 goto failed;
727
728 tail->m_next = mp;
729 tail = mp;
730 if (len > MINCLSIZE) {
731 MCLGET(mp, how);
732 if ((mp->m_flags & M_EXT) == 0)
733 goto failed;
734 }
735
736 mp->m_len = 0;
737 len -= M_TRAILINGSPACE(mp);
738 }
739
740 if (mtail != NULL)
741 mtail->m_next = top;
742 return (m);
743
744failed:
745 m_freem(top);
746 return (NULL);
747}
748
749/*
b6650ec0
MD
750 * m_mclalloc() - Allocates an mbuf cluster.
751 */
752caddr_t
753m_mclalloc(int how)
754{
755 caddr_t mp;
756 int s;
757
758 s = splimp();
759
760 if (mclfree == NULL)
761 m_clalloc(1, how);
762 mp = (caddr_t)mclfree;
763 if (mp != NULL) {
764 mclrefcnt[mtocl(mp)]++;
765 mbstat.m_clfree--;
766 mclfree = ((union mcluster *)mp)->mcl_next;
767 splx(s);
768 return(mp);
769 }
770 splx(s);
771 if (how == M_WAIT)
772 return(m_clalloc_wait());
773 return(NULL);
774}
775
776/*
777 * m_mclget() - Adds a cluster to a normal mbuf, M_EXT is set on success.
778 */
779void
780m_mclget(struct mbuf *m, int how)
781{
782 m->m_ext.ext_buf = m_mclalloc(how);
783 if (m->m_ext.ext_buf != NULL) {
784 m->m_data = m->m_ext.ext_buf;
785 m->m_flags |= M_EXT;
786 m->m_ext.ext_free = NULL;
787 m->m_ext.ext_ref = NULL;
788 m->m_ext.ext_size = MCLBYTES;
789 }
790}
791
792static __inline void
793_m_mclfree(caddr_t data)
794{
795 union mcluster *mp = (union mcluster *)data;
796
797 KASSERT(mclrefcnt[mtocl(mp)] > 0, ("freeing free cluster"));
798 if (--mclrefcnt[mtocl(mp)] == 0) {
799 mp->mcl_next = mclfree;
800 mclfree = mp;
801 mbstat.m_clfree++;
802 MCLWAKEUP();
803 }
804}
805
806void
807m_mclfree(caddr_t mp)
808{
809 int s = splimp();
810 _m_mclfree(mp);
811 splx(s);
812}
813
814/*
815 * m_free()
816 *
817 * Free a single mbuf and any associated external storage. The successor,
818 * if any, is returned.
984263bc 819 *
b6650ec0 820 * We do need to check non-first mbuf for m_aux, since some of existing
984263bc
MD
821 * code does not call M_PREPEND properly.
822 * (example: call to bpf_mtap from drivers)
823 */
984263bc 824struct mbuf *
b6650ec0 825m_free(struct mbuf *m)
984263bc 826{
b6650ec0
MD
827 int s;
828 struct mbuf *n;
829
830 s = splimp();
831 KASSERT(m->m_type != MT_FREE, ("freeing free mbuf"));
832 mbtypes[m->m_type]--;
833 if ((m->m_flags & M_PKTHDR) != 0)
834 m_tag_delete_chain(m, NULL);
835 if (m->m_flags & M_EXT) {
836 if (m->m_ext.ext_free != NULL) {
837 m->m_ext.ext_free(m->m_ext.ext_buf, m->m_ext.ext_size);
838 } else {
839 _m_mclfree(m->m_ext.ext_buf); /* inlined */
840 }
841 }
842 n = m->m_next;
843 m->m_type = MT_FREE;
844 mbtypes[MT_FREE]++;
845 m->m_next = mmbfree;
846 mmbfree = m;
847 MMBWAKEUP();
848 splx(s);
984263bc 849
984263bc
MD
850 return (n);
851}
852
853void
b6650ec0 854m_freem(struct mbuf *m)
984263bc
MD
855{
856 int s = splimp();
857
858 /*
859 * Try to keep a small pool of mbuf+cluster for quick use in
860 * device drivers. A good candidate is a M_PKTHDR buffer with
861 * only one cluster attached. Other mbufs, or those exceeding
862 * the pool size, are just m_free'd in the usual way.
863 * The following code makes sure that m_next, m_type,
864 * m_pkthdr.aux and m_ext.* are properly initialized.
865 * Other fields in the mbuf are initialized in m_getcl()
866 * upon allocation.
867 */
868 if (mcl_pool_now < mcl_pool_max && m && m->m_next == NULL &&
869 (m->m_flags & (M_PKTHDR|M_EXT)) == (M_PKTHDR|M_EXT) &&
870 m->m_type == MT_DATA && M_EXT_WRITABLE(m) ) {
871 m_tag_delete_chain(m, NULL);
872 m->m_nextpkt = mcl_pool;
873 mcl_pool = m;
874 mcl_pool_now++;
875 } else {
876 while (m)
877 m = m_free(m);
878 }
879 splx(s);
880}
881
882/*
883 * Mbuffer utility routines.
884 */
885
886/*
887 * Lesser-used path for M_PREPEND:
888 * allocate new mbuf to prepend to chain,
889 * copy junk along.
890 */
891struct mbuf *
892m_prepend(m, len, how)
893 register struct mbuf *m;
894 int len, how;
895{
896 struct mbuf *mn;
897
898 MGET(mn, how, m->m_type);
899 if (mn == (struct mbuf *)NULL) {
900 m_freem(m);
901 return ((struct mbuf *)NULL);
902 }
903 if (m->m_flags & M_PKTHDR)
904 M_MOVE_PKTHDR(mn, m);
905 mn->m_next = m;
906 m = mn;
907 if (len < MHLEN)
908 MH_ALIGN(m, len);
909 m->m_len = len;
910 return (m);
911}
912
913/*
914 * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
915 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf.
916 * The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller.
917 * Note that the copy is read-only, because clusters are not copied,
918 * only their reference counts are incremented.
919 */
920#define MCFail (mbstat.m_mcfail)
921
922struct mbuf *
923m_copym(m, off0, len, wait)
f15db79e 924 const struct mbuf *m;
984263bc
MD
925 int off0, wait;
926 register int len;
927{
928 register struct mbuf *n, **np;
929 register int off = off0;
930 struct mbuf *top;
931 int copyhdr = 0;
932
933 KASSERT(off >= 0, ("m_copym, negative off %d", off));
934 KASSERT(len >= 0, ("m_copym, negative len %d", len));
935 if (off == 0 && m->m_flags & M_PKTHDR)
936 copyhdr = 1;
937 while (off > 0) {
938 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain"));
939 if (off < m->m_len)
940 break;
941 off -= m->m_len;
942 m = m->m_next;
943 }
944 np = &top;
945 top = 0;
946 while (len > 0) {
947 if (m == 0) {
948 KASSERT(len == M_COPYALL,
949 ("m_copym, length > size of mbuf chain"));
950 break;
951 }
952 MGET(n, wait, m->m_type);
953 *np = n;
954 if (n == 0)
955 goto nospace;
956 if (copyhdr) {
957 if (!m_dup_pkthdr(n, m, wait))
958 goto nospace;
959 if (len == M_COPYALL)
960 n->m_pkthdr.len -= off0;
961 else
962 n->m_pkthdr.len = len;
963 copyhdr = 0;
964 }
965 n->m_len = min(len, m->m_len - off);
966 if (m->m_flags & M_EXT) {
967 n->m_data = m->m_data + off;
968 if (m->m_ext.ext_ref == NULL) {
969 atomic_add_char(
970 &mclrefcnt[mtocl(m->m_ext.ext_buf)], 1);
971 } else {
972 int s = splimp();
973
974 (*m->m_ext.ext_ref)(m->m_ext.ext_buf,
975 m->m_ext.ext_size);
976 splx(s);
977 }
978 n->m_ext = m->m_ext;
979 n->m_flags |= M_EXT;
980 } else
981 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
982 (unsigned)n->m_len);
983 if (len != M_COPYALL)
984 len -= n->m_len;
985 off = 0;
986 m = m->m_next;
987 np = &n->m_next;
988 }
989 if (top == 0)
990 MCFail++;
991 return (top);
992nospace:
993 m_freem(top);
994 MCFail++;
995 return (0);
996}
997
998/*
999 * Copy an entire packet, including header (which must be present).
1000 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
1001 * Note that the copy is read-only, because clusters are not copied,
1002 * only their reference counts are incremented.
1003 * Preserve alignment of the first mbuf so if the creator has left
1004 * some room at the beginning (e.g. for inserting protocol headers)
1005 * the copies also have the room available.
1006 */
1007struct mbuf *
1008m_copypacket(m, how)
1009 struct mbuf *m;
1010 int how;
1011{
1012 struct mbuf *top, *n, *o;
1013
1014 MGET(n, how, m->m_type);
1015 top = n;
1016 if (!n)
1017 goto nospace;
1018
1019 if (!m_dup_pkthdr(n, m, how))
1020 goto nospace;
1021 n->m_len = m->m_len;
1022 if (m->m_flags & M_EXT) {
1023 n->m_data = m->m_data;
1024 if (m->m_ext.ext_ref == NULL)
1025 atomic_add_char(&mclrefcnt[mtocl(m->m_ext.ext_buf)], 1);
1026 else {
1027 int s = splimp();
1028
1029 (*m->m_ext.ext_ref)(m->m_ext.ext_buf,
1030 m->m_ext.ext_size);
1031 splx(s);
1032 }
1033 n->m_ext = m->m_ext;
1034 n->m_flags |= M_EXT;
1035 } else {
1036 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat );
1037 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
1038 }
1039
1040 m = m->m_next;
1041 while (m) {
1042 MGET(o, how, m->m_type);
1043 if (!o)
1044 goto nospace;
1045
1046 n->m_next = o;
1047 n = n->m_next;
1048
1049 n->m_len = m->m_len;
1050 if (m->m_flags & M_EXT) {
1051 n->m_data = m->m_data;
1052 if (m->m_ext.ext_ref == NULL) {
1053 atomic_add_char(
1054 &mclrefcnt[mtocl(m->m_ext.ext_buf)], 1);
1055 } else {
1056 int s = splimp();
1057
1058 (*m->m_ext.ext_ref)(m->m_ext.ext_buf,
1059 m->m_ext.ext_size);
1060 splx(s);
1061 }
1062 n->m_ext = m->m_ext;
1063 n->m_flags |= M_EXT;
1064 } else {
1065 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
1066 }
1067
1068 m = m->m_next;
1069 }
1070 return top;
1071nospace:
1072 m_freem(top);
1073 MCFail++;
1074 return 0;
1075}
1076
1077/*
1078 * Copy data from an mbuf chain starting "off" bytes from the beginning,
1079 * continuing for "len" bytes, into the indicated buffer.
1080 */
1081void
1082m_copydata(m, off, len, cp)
f15db79e 1083 const struct mbuf *m;
984263bc
MD
1084 register int off;
1085 register int len;
1086 caddr_t cp;
1087{
1088 register unsigned count;
1089
1090 KASSERT(off >= 0, ("m_copydata, negative off %d", off));
1091 KASSERT(len >= 0, ("m_copydata, negative len %d", len));
1092 while (off > 0) {
1093 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain"));
1094 if (off < m->m_len)
1095 break;
1096 off -= m->m_len;
1097 m = m->m_next;
1098 }
1099 while (len > 0) {
1100 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain"));
1101 count = min(m->m_len - off, len);
1102 bcopy(mtod(m, caddr_t) + off, cp, count);
1103 len -= count;
1104 cp += count;
1105 off = 0;
1106 m = m->m_next;
1107 }
1108}
1109
1110/*
1111 * Copy a packet header mbuf chain into a completely new chain, including
1112 * copying any mbuf clusters. Use this instead of m_copypacket() when
1113 * you need a writable copy of an mbuf chain.
1114 */
1115struct mbuf *
1116m_dup(m, how)
1117 struct mbuf *m;
1118 int how;
1119{
1120 struct mbuf **p, *top = NULL;
1121 int remain, moff, nsize;
1122
1123 /* Sanity check */
1124 if (m == NULL)
1125 return (0);
1126 KASSERT((m->m_flags & M_PKTHDR) != 0, ("%s: !PKTHDR", __FUNCTION__));
1127
1128 /* While there's more data, get a new mbuf, tack it on, and fill it */
1129 remain = m->m_pkthdr.len;
1130 moff = 0;
1131 p = &top;
1132 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */
1133 struct mbuf *n;
1134
1135 /* Get the next new mbuf */
1136 MGET(n, how, m->m_type);
1137 if (n == NULL)
1138 goto nospace;
1139 if (top == NULL) { /* first one, must be PKTHDR */
1140 if (!m_dup_pkthdr(n, m, how))
1141 goto nospace;
1142 nsize = MHLEN;
1143 } else /* not the first one */
1144 nsize = MLEN;
1145 if (remain >= MINCLSIZE) {
1146 MCLGET(n, how);
1147 if ((n->m_flags & M_EXT) == 0) {
1148 (void)m_free(n);
1149 goto nospace;
1150 }
1151 nsize = MCLBYTES;
1152 }
1153 n->m_len = 0;
1154
1155 /* Link it into the new chain */
1156 *p = n;
1157 p = &n->m_next;
1158
1159 /* Copy data from original mbuf(s) into new mbuf */
1160 while (n->m_len < nsize && m != NULL) {
1161 int chunk = min(nsize - n->m_len, m->m_len - moff);
1162
1163 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk);
1164 moff += chunk;
1165 n->m_len += chunk;
1166 remain -= chunk;
1167 if (moff == m->m_len) {
1168 m = m->m_next;
1169 moff = 0;
1170 }
1171 }
1172
1173 /* Check correct total mbuf length */
1174 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL),
1175 ("%s: bogus m_pkthdr.len", __FUNCTION__));
1176 }
1177 return (top);
1178
1179nospace:
1180 m_freem(top);
1181 MCFail++;
1182 return (0);
1183}
1184
1185/*
1186 * Concatenate mbuf chain n to m.
1187 * Both chains must be of the same type (e.g. MT_DATA).
1188 * Any m_pkthdr is not updated.
1189 */
1190void
1191m_cat(m, n)
1192 register struct mbuf *m, *n;
1193{
1194 while (m->m_next)
1195 m = m->m_next;
1196 while (n) {
1197 if (m->m_flags & M_EXT ||
1198 m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) {
1199 /* just join the two chains */
1200 m->m_next = n;
1201 return;
1202 }
1203 /* splat the data from one into the other */
1204 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1205 (u_int)n->m_len);
1206 m->m_len += n->m_len;
1207 n = m_free(n);
1208 }
1209}
1210
1211void
1212m_adj(mp, req_len)
1213 struct mbuf *mp;
1214 int req_len;
1215{
1216 register int len = req_len;
1217 register struct mbuf *m;
1218 register int count;
1219
1220 if ((m = mp) == NULL)
1221 return;
1222 if (len >= 0) {
1223 /*
1224 * Trim from head.
1225 */
1226 while (m != NULL && len > 0) {
1227 if (m->m_len <= len) {
1228 len -= m->m_len;
1229 m->m_len = 0;
1230 m = m->m_next;
1231 } else {
1232 m->m_len -= len;
1233 m->m_data += len;
1234 len = 0;
1235 }
1236 }
1237 m = mp;
1238 if (mp->m_flags & M_PKTHDR)
1239 m->m_pkthdr.len -= (req_len - len);
1240 } else {
1241 /*
1242 * Trim from tail. Scan the mbuf chain,
1243 * calculating its length and finding the last mbuf.
1244 * If the adjustment only affects this mbuf, then just
1245 * adjust and return. Otherwise, rescan and truncate
1246 * after the remaining size.
1247 */
1248 len = -len;
1249 count = 0;
1250 for (;;) {
1251 count += m->m_len;
1252 if (m->m_next == (struct mbuf *)0)
1253 break;
1254 m = m->m_next;
1255 }
1256 if (m->m_len >= len) {
1257 m->m_len -= len;
1258 if (mp->m_flags & M_PKTHDR)
1259 mp->m_pkthdr.len -= len;
1260 return;
1261 }
1262 count -= len;
1263 if (count < 0)
1264 count = 0;
1265 /*
1266 * Correct length for chain is "count".
1267 * Find the mbuf with last data, adjust its length,
1268 * and toss data from remaining mbufs on chain.
1269 */
1270 m = mp;
1271 if (m->m_flags & M_PKTHDR)
1272 m->m_pkthdr.len = count;
1273 for (; m; m = m->m_next) {
1274 if (m->m_len >= count) {
1275 m->m_len = count;
1276 break;
1277 }
1278 count -= m->m_len;
1279 }
1280 while (m->m_next)
1281 (m = m->m_next) ->m_len = 0;
1282 }
1283}
1284
1285/*
1286 * Rearange an mbuf chain so that len bytes are contiguous
1287 * and in the data area of an mbuf (so that mtod and dtom
1288 * will work for a structure of size len). Returns the resulting
1289 * mbuf chain on success, frees it and returns null on failure.
1290 * If there is room, it will add up to max_protohdr-len extra bytes to the
1291 * contiguous region in an attempt to avoid being called next time.
1292 */
1293#define MPFail (mbstat.m_mpfail)
1294
1295struct mbuf *
1296m_pullup(n, len)
1297 register struct mbuf *n;
1298 int len;
1299{
1300 register struct mbuf *m;
1301 register int count;
1302 int space;
1303
1304 /*
1305 * If first mbuf has no cluster, and has room for len bytes
1306 * without shifting current data, pullup into it,
1307 * otherwise allocate a new mbuf to prepend to the chain.
1308 */
1309 if ((n->m_flags & M_EXT) == 0 &&
1310 n->m_data + len < &n->m_dat[MLEN] && n->m_next) {
1311 if (n->m_len >= len)
1312 return (n);
1313 m = n;
1314 n = n->m_next;
1315 len -= m->m_len;
1316 } else {
1317 if (len > MHLEN)
1318 goto bad;
1319 MGET(m, M_DONTWAIT, n->m_type);
1320 if (m == 0)
1321 goto bad;
1322 m->m_len = 0;
1323 if (n->m_flags & M_PKTHDR)
1324 M_MOVE_PKTHDR(m, n);
1325 }
1326 space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
1327 do {
1328 count = min(min(max(len, max_protohdr), space), n->m_len);
1329 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1330 (unsigned)count);
1331 len -= count;
1332 m->m_len += count;
1333 n->m_len -= count;
1334 space -= count;
1335 if (n->m_len)
1336 n->m_data += count;
1337 else
1338 n = m_free(n);
1339 } while (len > 0 && n);
1340 if (len > 0) {
1341 (void) m_free(m);
1342 goto bad;
1343 }
1344 m->m_next = n;
1345 return (m);
1346bad:
1347 m_freem(n);
1348 MPFail++;
1349 return (0);
1350}
1351
1352/*
1353 * Partition an mbuf chain in two pieces, returning the tail --
1354 * all but the first len0 bytes. In case of failure, it returns NULL and
1355 * attempts to restore the chain to its original state.
1356 *
1357 * Note that the resulting mbufs might be read-only, because the new
1358 * mbuf can end up sharing an mbuf cluster with the original mbuf if
1359 * the "breaking point" happens to lie within a cluster mbuf. Use the
1360 * M_WRITABLE() macro to check for this case.
1361 */
1362struct mbuf *
1363m_split(m0, len0, wait)
1364 register struct mbuf *m0;
1365 int len0, wait;
1366{
1367 register struct mbuf *m, *n;
1368 unsigned len = len0, remain;
1369
1370 for (m = m0; m && len > m->m_len; m = m->m_next)
1371 len -= m->m_len;
1372 if (m == 0)
1373 return (0);
1374 remain = m->m_len - len;
1375 if (m0->m_flags & M_PKTHDR) {
1376 MGETHDR(n, wait, m0->m_type);
1377 if (n == 0)
1378 return (0);
1379 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
1380 n->m_pkthdr.len = m0->m_pkthdr.len - len0;
1381 m0->m_pkthdr.len = len0;
1382 if (m->m_flags & M_EXT)
1383 goto extpacket;
1384 if (remain > MHLEN) {
1385 /* m can't be the lead packet */
1386 MH_ALIGN(n, 0);
1387 n->m_next = m_split(m, len, wait);
1388 if (n->m_next == 0) {
1389 (void) m_free(n);
1390 return (0);
1391 } else {
1392 n->m_len = 0;
1393 return (n);
1394 }
1395 } else
1396 MH_ALIGN(n, remain);
1397 } else if (remain == 0) {
1398 n = m->m_next;
1399 m->m_next = 0;
1400 return (n);
1401 } else {
1402 MGET(n, wait, m->m_type);
1403 if (n == 0)
1404 return (0);
1405 M_ALIGN(n, remain);
1406 }
1407extpacket:
1408 if (m->m_flags & M_EXT) {
1409 n->m_flags |= M_EXT;
1410 n->m_ext = m->m_ext;
1411 if (m->m_ext.ext_ref == NULL)
1412 atomic_add_char(&mclrefcnt[mtocl(m->m_ext.ext_buf)], 1);
1413 else {
1414 int s = splimp();
1415
1416 (*m->m_ext.ext_ref)(m->m_ext.ext_buf,
1417 m->m_ext.ext_size);
1418 splx(s);
1419 }
1420 n->m_data = m->m_data + len;
1421 } else {
1422 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain);
1423 }
1424 n->m_len = remain;
1425 m->m_len = len;
1426 n->m_next = m->m_next;
1427 m->m_next = 0;
1428 return (n);
1429}
1430/*
1431 * Routine to copy from device local memory into mbufs.
1432 */
1433struct mbuf *
1434m_devget(buf, totlen, off0, ifp, copy)
1435 char *buf;
1436 int totlen, off0;
1437 struct ifnet *ifp;
1438 void (*copy) __P((char *from, caddr_t to, u_int len));
1439{
1440 register struct mbuf *m;
1441 struct mbuf *top = 0, **mp = &top;
1442 register int off = off0, len;
1443 register char *cp;
1444 char *epkt;
1445
1446 cp = buf;
1447 epkt = cp + totlen;
1448 if (off) {
1449 cp += off + 2 * sizeof(u_short);
1450 totlen -= 2 * sizeof(u_short);
1451 }
1452 MGETHDR(m, M_DONTWAIT, MT_DATA);
1453 if (m == 0)
1454 return (0);
1455 m->m_pkthdr.rcvif = ifp;
1456 m->m_pkthdr.len = totlen;
1457 m->m_len = MHLEN;
1458
1459 while (totlen > 0) {
1460 if (top) {
1461 MGET(m, M_DONTWAIT, MT_DATA);
1462 if (m == 0) {
1463 m_freem(top);
1464 return (0);
1465 }
1466 m->m_len = MLEN;
1467 }
1468 len = min(totlen, epkt - cp);
1469 if (len >= MINCLSIZE) {
1470 MCLGET(m, M_DONTWAIT);
1471 if (m->m_flags & M_EXT)
1472 m->m_len = len = min(len, MCLBYTES);
1473 else
1474 len = m->m_len;
1475 } else {
1476 /*
1477 * Place initial small packet/header at end of mbuf.
1478 */
1479 if (len < m->m_len) {
1480 if (top == 0 && len + max_linkhdr <= m->m_len)
1481 m->m_data += max_linkhdr;
1482 m->m_len = len;
1483 } else
1484 len = m->m_len;
1485 }
1486 if (copy)
1487 copy(cp, mtod(m, caddr_t), (unsigned)len);
1488 else
1489 bcopy(cp, mtod(m, caddr_t), (unsigned)len);
1490 cp += len;
1491 *mp = m;
1492 mp = &m->m_next;
1493 totlen -= len;
1494 if (cp == epkt)
1495 cp = buf;
1496 }
1497 return (top);
1498}
1499
1500/*
1501 * Copy data from a buffer back into the indicated mbuf chain,
1502 * starting "off" bytes from the beginning, extending the mbuf
1503 * chain if necessary.
1504 */
1505void
1506m_copyback(m0, off, len, cp)
1507 struct mbuf *m0;
1508 register int off;
1509 register int len;
1510 caddr_t cp;
1511{
1512 register int mlen;
1513 register struct mbuf *m = m0, *n;
1514 int totlen = 0;
1515
1516 if (m0 == 0)
1517 return;
1518 while (off > (mlen = m->m_len)) {
1519 off -= mlen;
1520 totlen += mlen;
1521 if (m->m_next == 0) {
1522 n = m_getclr(M_DONTWAIT, m->m_type);
1523 if (n == 0)
1524 goto out;
1525 n->m_len = min(MLEN, len + off);
1526 m->m_next = n;
1527 }
1528 m = m->m_next;
1529 }
1530 while (len > 0) {
1531 mlen = min (m->m_len - off, len);
1532 bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen);
1533 cp += mlen;
1534 len -= mlen;
1535 mlen += off;
1536 off = 0;
1537 totlen += mlen;
1538 if (len == 0)
1539 break;
1540 if (m->m_next == 0) {
1541 n = m_get(M_DONTWAIT, m->m_type);
1542 if (n == 0)
1543 break;
1544 n->m_len = min(MLEN, len);
1545 m->m_next = n;
1546 }
1547 m = m->m_next;
1548 }
1549out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
1550 m->m_pkthdr.len = totlen;
1551}
1552
1553void
1554m_print(const struct mbuf *m)
1555{
1556 int len;
1557 const struct mbuf *m2;
1558
1559 len = m->m_pkthdr.len;
1560 m2 = m;
1561 while (len) {
1562 printf("%p %*D\n", m2, m2->m_len, (u_char *)m2->m_data, "-");
1563 len -= m2->m_len;
1564 m2 = m2->m_next;
1565 }
1566 return;
1567}
1568
1569/*
1570 * "Move" mbuf pkthdr from "from" to "to".
1571 * "from" must have M_PKTHDR set, and "to" must be empty.
1572 */
1573void
1574m_move_pkthdr(struct mbuf *to, struct mbuf *from)
1575{
1576 KASSERT((to->m_flags & M_EXT) == 0, ("m_move_pkthdr: to has cluster"));
1577
1578 to->m_flags = from->m_flags & M_COPYFLAGS;
1579 to->m_data = to->m_pktdat;
1580 to->m_pkthdr = from->m_pkthdr; /* especially tags */
1581 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */
1582 from->m_flags &= ~M_PKTHDR;
1583}
1584
1585/*
1586 * Duplicate "from"'s mbuf pkthdr in "to".
1587 * "from" must have M_PKTHDR set, and "to" must be empty.
1588 * In particular, this does a deep copy of the packet tags.
1589 */
1590int
f15db79e 1591m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how)
984263bc
MD
1592{
1593 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
1594 if ((to->m_flags & M_EXT) == 0)
1595 to->m_data = to->m_pktdat;
1596 to->m_pkthdr = from->m_pkthdr;
1597 SLIST_INIT(&to->m_pkthdr.tags);
1598 return (m_tag_copy_chain(to, from, how));
1599}
1600
1601/*
1602 * Defragment a mbuf chain, returning the shortest possible
1603 * chain of mbufs and clusters. If allocation fails and
1604 * this cannot be completed, NULL will be returned, but
1605 * the passed in chain will be unchanged. Upon success,
1606 * the original chain will be freed, and the new chain
1607 * will be returned.
1608 *
1609 * If a non-packet header is passed in, the original
1610 * mbuf (chain?) will be returned unharmed.
1611 */
1612struct mbuf *
1613m_defrag(struct mbuf *m0, int how)
1614{
1615 struct mbuf *m_new = NULL, *m_final = NULL;
1616 int progress = 0, length;
1617
1618 if (!(m0->m_flags & M_PKTHDR))
1619 return (m0);
1620
1621#ifdef MBUF_STRESS_TEST
1622 if (m_defragrandomfailures) {
1623 int temp = arc4random() & 0xff;
1624 if (temp == 0xba)
1625 goto nospace;
1626 }
1627#endif
1628
1629 if (m0->m_pkthdr.len > MHLEN)
1630 m_final = m_getcl(how, MT_DATA, M_PKTHDR);
1631 else
1632 m_final = m_gethdr(how, MT_DATA);
1633
1634 if (m_final == NULL)
1635 goto nospace;
1636
1637 if (m_dup_pkthdr(m_final, m0, how) == NULL)
1638 goto nospace;
1639
1640 m_new = m_final;
1641
1642 while (progress < m0->m_pkthdr.len) {
1643 length = m0->m_pkthdr.len - progress;
1644 if (length > MCLBYTES)
1645 length = MCLBYTES;
1646
1647 if (m_new == NULL) {
1648 if (length > MLEN)
1649 m_new = m_getcl(how, MT_DATA, 0);
1650 else
1651 m_new = m_get(how, MT_DATA);
1652 if (m_new == NULL)
1653 goto nospace;
1654 }
1655
1656 m_copydata(m0, progress, length, mtod(m_new, caddr_t));
1657 progress += length;
1658 m_new->m_len = length;
1659 if (m_new != m_final)
1660 m_cat(m_final, m_new);
1661 m_new = NULL;
1662 }
1663 if (m0->m_next == NULL)
1664 m_defraguseless++;
1665 m_freem(m0);
1666 m0 = m_final;
1667 m_defragpackets++;
1668 m_defragbytes += m0->m_pkthdr.len;
1669 return (m0);
1670nospace:
1671 m_defragfailure++;
1672 if (m_new)
1673 m_free(m_new);
1674 if (m_final)
1675 m_freem(m_final);
1676 return (NULL);
1677}