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 $ 35 * $DragonFly: src/sys/kern/uipc_mbuf.c,v 1.13 2003/10/15 16:48:03 hmp Exp $ 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> 48 #include <sys/thread.h> 49 #include <sys/globaldata.h> 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 59 static void mbinit (void *); 60 SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL) 61 62 struct mbuf *mbutl; 63 char *mclrefcnt; 64 struct mbstat mbstat; 65 u_long mbtypes[MT_NTYPES]; 66 struct mbuf *mmbfree; 67 union mcluster *mclfree; 68 int max_linkhdr; 69 int max_protohdr; 70 int max_hdr; 71 int max_datalen; 72 int m_defragpackets; 73 int m_defragbytes; 74 int m_defraguseless; 75 int m_defragfailure; 76 #ifdef MBUF_STRESS_TEST 77 int m_defragrandomfailures; 78 #endif 79 80 int nmbclusters; 81 int nmbufs; 82 u_int m_mballoc_wid = 0; 83 u_int m_clalloc_wid = 0; 84 85 SYSCTL_DECL(_kern_ipc); 86 SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW, 87 &max_linkhdr, 0, ""); 88 SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW, 89 &max_protohdr, 0, ""); 90 SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0, ""); 91 SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW, 92 &max_datalen, 0, ""); 93 SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_wait, CTLFLAG_RW, 94 &mbuf_wait, 0, ""); 95 SYSCTL_STRUCT(_kern_ipc, KIPC_MBSTAT, mbstat, CTLFLAG_RW, &mbstat, mbstat, ""); 96 SYSCTL_OPAQUE(_kern_ipc, OID_AUTO, mbtypes, CTLFLAG_RD, mbtypes, 97 sizeof(mbtypes), "LU", ""); 98 SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters, CTLFLAG_RD, 99 &nmbclusters, 0, "Maximum number of mbuf clusters available"); 100 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbufs, CTLFLAG_RD, &nmbufs, 0, 101 "Maximum number of mbufs available"); 102 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD, 103 &m_defragpackets, 0, ""); 104 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD, 105 &m_defragbytes, 0, ""); 106 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD, 107 &m_defraguseless, 0, ""); 108 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD, 109 &m_defragfailure, 0, ""); 110 #ifdef MBUF_STRESS_TEST 111 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW, 112 &m_defragrandomfailures, 0, ""); 113 #endif 114 115 static void m_reclaim (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 */ 127 static void 128 tunable_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 } 144 SYSINIT(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*/ 152 static void 153 mbinit(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; 178 bad: 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 */ 187 int 188 m_mballoc(nmb, how) 189 int nmb; 190 int how; 191 { 192 caddr_t p; 193 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 */ 248 struct mbuf * 249 m_mballoc_wait(int caller, int type) 250 { 251 struct mbuf *p; 252 int s; 253 254 s = splimp(); 255 m_mballoc_wid++; 256 if ((tsleep(&m_mballoc_wid, 0, "mballc", mbuf_wait)) == EWOULDBLOCK) 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 291 static int i_want_my_mcl; 292 293 static void 294 kproc_mclalloc(void) 295 { 296 int status; 297 298 while (1) { 299 tsleep(&i_want_my_mcl, 0, "mclalloc", 0); 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 } 307 308 static struct thread *mclallocthread; 309 static struct kproc_desc mclalloc_kp = { 310 "mclalloc", 311 kproc_mclalloc, 312 &mclallocthread 313 }; 314 SYSINIT(mclallocthread, SI_SUB_KTHREAD_UPDATE, SI_ORDER_ANY, kproc_start, 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 */ 324 int 325 m_clalloc(ncl, how) 326 int ncl; 327 int how; 328 { 329 caddr_t p; 330 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 = contigmalloc_map(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) */ 372 m_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 */ 397 caddr_t 398 m_clalloc_wait(void) 399 { 400 caddr_t p; 401 int s; 402 403 /* If in interrupt context, and INVARIANTS, maintain sanity and die. */ 404 KASSERT(mycpu->gd_intr_nesting_level == 0, ("CLALLOC: CANNOT WAIT IN INTERRUPT")); 405 406 /* Sleep until something's available or until we expire. */ 407 m_clalloc_wid++; 408 if ((tsleep(&m_clalloc_wid, 0, "mclalc", mbuf_wait)) == EWOULDBLOCK) 409 m_clalloc_wid--; 410 411 /* 412 * Now that we (think) that we've got something, we will redo and 413 * MGET, but avoid getting into another instance of m_clalloc_wait() 414 */ 415 p = m_mclalloc(M_DONTWAIT); 416 417 s = splimp(); 418 if (p != NULL) { /* We waited and got something... */ 419 mbstat.m_wait++; 420 /* Wake up another if we have more free. */ 421 if (mclfree != NULL) 422 MCLWAKEUP(); 423 } 424 425 splx(s); 426 return (p); 427 } 428 429 /* 430 * When MGET fails, ask protocols to free space when short of memory, 431 * then re-attempt to allocate an mbuf. 432 */ 433 struct mbuf * 434 m_retry(i, t) 435 int i, t; 436 { 437 struct mbuf *m; 438 int ms; 439 440 /* 441 * Must only do the reclaim if not in an interrupt context. 442 */ 443 if (i == M_WAIT) { 444 KASSERT(mycpu->gd_intr_nesting_level == 0, 445 ("MBALLOC: CANNOT WAIT IN INTERRUPT")); 446 m_reclaim(); 447 } 448 449 ms = splimp(); 450 if (mmbfree == NULL) 451 (void)m_mballoc(1, i); 452 m = mmbfree; 453 if (m != NULL) { 454 mmbfree = m->m_next; 455 mbtypes[MT_FREE]--; 456 m->m_type = t; 457 mbtypes[t]++; 458 m->m_next = NULL; 459 m->m_nextpkt = NULL; 460 m->m_data = m->m_dat; 461 m->m_flags = 0; 462 splx(ms); 463 mbstat.m_wait++; 464 } else { 465 static int last_report ; /* when we did that (in ticks) */ 466 467 splx(ms); 468 mbstat.m_drops++; 469 if (ticks < last_report || (ticks - last_report) >= hz) { 470 last_report = ticks; 471 printf("All mbufs exhausted, please see tuning(7).\n"); 472 } 473 } 474 475 return (m); 476 } 477 478 /* 479 * As above; retry an MGETHDR. 480 */ 481 struct mbuf * 482 m_retryhdr(i, t) 483 int i, t; 484 { 485 struct mbuf *m; 486 int ms; 487 488 /* 489 * Must only do the reclaim if not in an interrupt context. 490 */ 491 if (i == M_WAIT) { 492 KASSERT(mycpu->gd_intr_nesting_level == 0, 493 ("MBALLOC: CANNOT WAIT IN INTERRUPT")); 494 m_reclaim(); 495 } 496 497 ms = splimp(); 498 if (mmbfree == NULL) 499 (void)m_mballoc(1, i); 500 m = mmbfree; 501 if (m != NULL) { 502 mmbfree = m->m_next; 503 mbtypes[MT_FREE]--; 504 m->m_type = t; 505 mbtypes[t]++; 506 m->m_next = NULL; 507 m->m_nextpkt = NULL; 508 m->m_data = m->m_pktdat; 509 m->m_flags = M_PKTHDR; 510 m->m_pkthdr.rcvif = NULL; 511 SLIST_INIT(&m->m_pkthdr.tags); 512 m->m_pkthdr.csum_flags = 0; 513 splx(ms); 514 mbstat.m_wait++; 515 } else { 516 static int last_report ; /* when we did that (in ticks) */ 517 518 splx(ms); 519 mbstat.m_drops++; 520 if (ticks < last_report || (ticks - last_report) >= hz) { 521 last_report = ticks; 522 printf("All mbufs exhausted, please see tuning(7).\n"); 523 } 524 } 525 526 return (m); 527 } 528 529 static void 530 m_reclaim() 531 { 532 struct domain *dp; 533 struct protosw *pr; 534 int s = splimp(); 535 536 for (dp = domains; dp; dp = dp->dom_next) 537 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) 538 if (pr->pr_drain) 539 (*pr->pr_drain)(); 540 splx(s); 541 mbstat.m_drain++; 542 } 543 544 /* 545 * Space allocation routines. 546 * These are also available as macros 547 * for critical paths. 548 */ 549 struct mbuf * 550 m_get(how, type) 551 int how, type; 552 { 553 struct mbuf *m; 554 int ms; 555 556 ms = splimp(); 557 if (mmbfree == NULL) 558 (void)m_mballoc(1, how); 559 m = mmbfree; 560 if (m != NULL) { 561 mmbfree = m->m_next; 562 mbtypes[MT_FREE]--; 563 m->m_type = type; 564 mbtypes[type]++; 565 m->m_next = NULL; 566 m->m_nextpkt = NULL; 567 m->m_data = m->m_dat; 568 m->m_flags = 0; 569 splx(ms); 570 } else { 571 splx(ms); 572 m = m_retry(how, type); 573 if (m == NULL && how == M_WAIT) 574 m = m_mballoc_wait(MGET_C, type); 575 } 576 return (m); 577 } 578 579 struct mbuf * 580 m_gethdr(how, type) 581 int how, type; 582 { 583 struct mbuf *m; 584 int ms; 585 586 ms = splimp(); 587 if (mmbfree == NULL) 588 (void)m_mballoc(1, how); 589 m = mmbfree; 590 if (m != NULL) { 591 mmbfree = m->m_next; 592 mbtypes[MT_FREE]--; 593 m->m_type = type; 594 mbtypes[type]++; 595 m->m_next = NULL; 596 m->m_nextpkt = NULL; 597 m->m_data = m->m_pktdat; 598 m->m_flags = M_PKTHDR; 599 m->m_pkthdr.rcvif = NULL; 600 SLIST_INIT(&m->m_pkthdr.tags); 601 m->m_pkthdr.csum_flags = 0; 602 splx(ms); 603 } else { 604 splx(ms); 605 m = m_retryhdr(how, type); 606 if (m == NULL && how == M_WAIT) 607 m = m_mballoc_wait(MGETHDR_C, type); 608 } 609 return (m); 610 } 611 612 struct mbuf * 613 m_getclr(how, type) 614 int how, type; 615 { 616 struct mbuf *m; 617 618 MGET(m, how, type); 619 if (m == 0) 620 return (0); 621 bzero(mtod(m, caddr_t), MLEN); 622 return (m); 623 } 624 625 /* 626 * m_getcl() returns an mbuf with an attached cluster. 627 * Because many network drivers use this kind of buffers a lot, it is 628 * convenient to keep a small pool of free buffers of this kind. 629 * Even a small size such as 10 gives about 10% improvement in the 630 * forwarding rate in a bridge or router. 631 * The size of this free list is controlled by the sysctl variable 632 * mcl_pool_max. The list is populated on m_freem(), and used in 633 * m_getcl() if elements are available. 634 */ 635 static struct mbuf *mcl_pool; 636 static int mcl_pool_now; 637 static int mcl_pool_max = 0; 638 639 SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_pool_max, CTLFLAG_RW, &mcl_pool_max, 0, 640 "Maximum number of mbufs+cluster in free list"); 641 SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_pool_now, CTLFLAG_RD, &mcl_pool_now, 0, 642 "Current number of mbufs+cluster in free list"); 643 644 struct mbuf * 645 m_getcl(int how, short type, int flags) 646 { 647 int s = splimp(); 648 struct mbuf *mp; 649 650 if (flags & M_PKTHDR) { 651 if (type == MT_DATA && mcl_pool) { 652 mp = mcl_pool; 653 mcl_pool = mp->m_nextpkt; 654 mcl_pool_now--; 655 splx(s); 656 mp->m_nextpkt = NULL; 657 mp->m_data = mp->m_ext.ext_buf; 658 mp->m_flags = M_PKTHDR|M_EXT; 659 mp->m_pkthdr.rcvif = NULL; 660 mp->m_pkthdr.csum_flags = 0; 661 return mp; 662 } else 663 MGETHDR(mp, how, type); 664 } else 665 MGET(mp, how, type); 666 if (mp) { 667 MCLGET(mp, how); 668 if ( (mp->m_flags & M_EXT) == 0) { 669 m_free(mp); 670 mp = NULL; 671 } 672 } 673 splx(s); 674 return mp; 675 } 676 677 /* 678 * struct mbuf * 679 * m_getm(m, len, how, type) 680 * 681 * This will allocate len-worth of mbufs and/or mbuf clusters (whatever fits 682 * best) and return a pointer to the top of the allocated chain. If m is 683 * non-null, then we assume that it is a single mbuf or an mbuf chain to 684 * which we want len bytes worth of mbufs and/or clusters attached, and so 685 * if we succeed in allocating it, we will just return a pointer to m. 686 * 687 * If we happen to fail at any point during the allocation, we will free 688 * up everything we have already allocated and return NULL. 689 * 690 */ 691 struct mbuf * 692 m_getm(struct mbuf *m, int len, int how, int type) 693 { 694 struct mbuf *top, *tail, *mp, *mtail = NULL; 695 696 KASSERT(len >= 0, ("len is < 0 in m_getm")); 697 698 MGET(mp, how, type); 699 if (mp == NULL) 700 return (NULL); 701 else if (len > MINCLSIZE) { 702 MCLGET(mp, how); 703 if ((mp->m_flags & M_EXT) == 0) { 704 m_free(mp); 705 return (NULL); 706 } 707 } 708 mp->m_len = 0; 709 len -= M_TRAILINGSPACE(mp); 710 711 if (m != NULL) 712 for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next); 713 else 714 m = mp; 715 716 top = tail = mp; 717 while (len > 0) { 718 MGET(mp, how, type); 719 if (mp == NULL) 720 goto failed; 721 722 tail->m_next = mp; 723 tail = mp; 724 if (len > MINCLSIZE) { 725 MCLGET(mp, how); 726 if ((mp->m_flags & M_EXT) == 0) 727 goto failed; 728 } 729 730 mp->m_len = 0; 731 len -= M_TRAILINGSPACE(mp); 732 } 733 734 if (mtail != NULL) 735 mtail->m_next = top; 736 return (m); 737 738 failed: 739 m_freem(top); 740 return (NULL); 741 } 742 743 /* 744 * m_mclalloc() - Allocates an mbuf cluster. 745 */ 746 caddr_t 747 m_mclalloc(int how) 748 { 749 caddr_t mp; 750 int s; 751 752 s = splimp(); 753 754 if (mclfree == NULL) 755 m_clalloc(1, how); 756 mp = (caddr_t)mclfree; 757 if (mp != NULL) { 758 mclrefcnt[mtocl(mp)]++; 759 mbstat.m_clfree--; 760 mclfree = ((union mcluster *)mp)->mcl_next; 761 splx(s); 762 return(mp); 763 } 764 splx(s); 765 if (how == M_WAIT) 766 return(m_clalloc_wait()); 767 return(NULL); 768 } 769 770 /* 771 * m_mclget() - Adds a cluster to a normal mbuf, M_EXT is set on success. 772 */ 773 void 774 m_mclget(struct mbuf *m, int how) 775 { 776 m->m_ext.ext_buf = m_mclalloc(how); 777 if (m->m_ext.ext_buf != NULL) { 778 m->m_data = m->m_ext.ext_buf; 779 m->m_flags |= M_EXT; 780 m->m_ext.ext_free = NULL; 781 m->m_ext.ext_ref = NULL; 782 m->m_ext.ext_size = MCLBYTES; 783 } 784 } 785 786 static __inline void 787 _m_mclfree(caddr_t data) 788 { 789 union mcluster *mp = (union mcluster *)data; 790 791 KASSERT(mclrefcnt[mtocl(mp)] > 0, ("freeing free cluster")); 792 if (--mclrefcnt[mtocl(mp)] == 0) { 793 mp->mcl_next = mclfree; 794 mclfree = mp; 795 mbstat.m_clfree++; 796 MCLWAKEUP(); 797 } 798 } 799 800 void 801 m_mclfree(caddr_t mp) 802 { 803 int s = splimp(); 804 _m_mclfree(mp); 805 splx(s); 806 } 807 808 /* 809 * m_free() 810 * 811 * Free a single mbuf and any associated external storage. The successor, 812 * if any, is returned. 813 * 814 * We do need to check non-first mbuf for m_aux, since some of existing 815 * code does not call M_PREPEND properly. 816 * (example: call to bpf_mtap from drivers) 817 */ 818 struct mbuf * 819 m_free(struct mbuf *m) 820 { 821 int s; 822 struct mbuf *n; 823 824 s = splimp(); 825 KASSERT(m->m_type != MT_FREE, ("freeing free mbuf")); 826 mbtypes[m->m_type]--; 827 if ((m->m_flags & M_PKTHDR) != 0) 828 m_tag_delete_chain(m, NULL); 829 if (m->m_flags & M_EXT) { 830 if (m->m_ext.ext_free != NULL) { 831 m->m_ext.ext_free(m->m_ext.ext_buf, m->m_ext.ext_size); 832 } else { 833 _m_mclfree(m->m_ext.ext_buf); /* inlined */ 834 } 835 } 836 n = m->m_next; 837 m->m_type = MT_FREE; 838 mbtypes[MT_FREE]++; 839 m->m_next = mmbfree; 840 mmbfree = m; 841 MMBWAKEUP(); 842 splx(s); 843 844 return (n); 845 } 846 847 void 848 m_freem(struct mbuf *m) 849 { 850 int s = splimp(); 851 852 /* 853 * Try to keep a small pool of mbuf+cluster for quick use in 854 * device drivers. A good candidate is a M_PKTHDR buffer with 855 * only one cluster attached. Other mbufs, or those exceeding 856 * the pool size, are just m_free'd in the usual way. 857 * The following code makes sure that m_next, m_type, 858 * m_pkthdr.aux and m_ext.* are properly initialized. 859 * Other fields in the mbuf are initialized in m_getcl() 860 * upon allocation. 861 */ 862 if (mcl_pool_now < mcl_pool_max && m && m->m_next == NULL && 863 (m->m_flags & (M_PKTHDR|M_EXT)) == (M_PKTHDR|M_EXT) && 864 m->m_type == MT_DATA && M_EXT_WRITABLE(m) ) { 865 m_tag_delete_chain(m, NULL); 866 m->m_nextpkt = mcl_pool; 867 mcl_pool = m; 868 mcl_pool_now++; 869 } else { 870 while (m) 871 m = m_free(m); 872 } 873 splx(s); 874 } 875 876 /* 877 * Mbuffer utility routines. 878 */ 879 880 /* 881 * Lesser-used path for M_PREPEND: 882 * allocate new mbuf to prepend to chain, 883 * copy junk along. 884 */ 885 struct mbuf * 886 m_prepend(m, len, how) 887 struct mbuf *m; 888 int len, how; 889 { 890 struct mbuf *mn; 891 892 MGET(mn, how, m->m_type); 893 if (mn == (struct mbuf *)NULL) { 894 m_freem(m); 895 return ((struct mbuf *)NULL); 896 } 897 if (m->m_flags & M_PKTHDR) 898 M_MOVE_PKTHDR(mn, m); 899 mn->m_next = m; 900 m = mn; 901 if (len < MHLEN) 902 MH_ALIGN(m, len); 903 m->m_len = len; 904 return (m); 905 } 906 907 /* 908 * Make a copy of an mbuf chain starting "off0" bytes from the beginning, 909 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf. 910 * The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller. 911 * Note that the copy is read-only, because clusters are not copied, 912 * only their reference counts are incremented. 913 */ 914 #define MCFail (mbstat.m_mcfail) 915 916 struct mbuf * 917 m_copym(m, off0, len, wait) 918 const struct mbuf *m; 919 int off0, wait; 920 int len; 921 { 922 struct mbuf *n, **np; 923 int off = off0; 924 struct mbuf *top; 925 int copyhdr = 0; 926 927 KASSERT(off >= 0, ("m_copym, negative off %d", off)); 928 KASSERT(len >= 0, ("m_copym, negative len %d", len)); 929 if (off == 0 && m->m_flags & M_PKTHDR) 930 copyhdr = 1; 931 while (off > 0) { 932 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain")); 933 if (off < m->m_len) 934 break; 935 off -= m->m_len; 936 m = m->m_next; 937 } 938 np = ⊤ 939 top = 0; 940 while (len > 0) { 941 if (m == 0) { 942 KASSERT(len == M_COPYALL, 943 ("m_copym, length > size of mbuf chain")); 944 break; 945 } 946 MGET(n, wait, m->m_type); 947 *np = n; 948 if (n == 0) 949 goto nospace; 950 if (copyhdr) { 951 if (!m_dup_pkthdr(n, m, wait)) 952 goto nospace; 953 if (len == M_COPYALL) 954 n->m_pkthdr.len -= off0; 955 else 956 n->m_pkthdr.len = len; 957 copyhdr = 0; 958 } 959 n->m_len = min(len, m->m_len - off); 960 if (m->m_flags & M_EXT) { 961 n->m_data = m->m_data + off; 962 if (m->m_ext.ext_ref == NULL) { 963 atomic_add_char( 964 &mclrefcnt[mtocl(m->m_ext.ext_buf)], 1); 965 } else { 966 int s = splimp(); 967 968 (*m->m_ext.ext_ref)(m->m_ext.ext_buf, 969 m->m_ext.ext_size); 970 splx(s); 971 } 972 n->m_ext = m->m_ext; 973 n->m_flags |= M_EXT; 974 } else 975 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t), 976 (unsigned)n->m_len); 977 if (len != M_COPYALL) 978 len -= n->m_len; 979 off = 0; 980 m = m->m_next; 981 np = &n->m_next; 982 } 983 if (top == 0) 984 MCFail++; 985 return (top); 986 nospace: 987 m_freem(top); 988 MCFail++; 989 return (0); 990 } 991 992 /* 993 * Copy an entire packet, including header (which must be present). 994 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'. 995 * Note that the copy is read-only, because clusters are not copied, 996 * only their reference counts are incremented. 997 * Preserve alignment of the first mbuf so if the creator has left 998 * some room at the beginning (e.g. for inserting protocol headers) 999 * the copies also have the room available. 1000 */ 1001 struct mbuf * 1002 m_copypacket(m, how) 1003 struct mbuf *m; 1004 int how; 1005 { 1006 struct mbuf *top, *n, *o; 1007 1008 MGET(n, how, m->m_type); 1009 top = n; 1010 if (!n) 1011 goto nospace; 1012 1013 if (!m_dup_pkthdr(n, m, how)) 1014 goto nospace; 1015 n->m_len = m->m_len; 1016 if (m->m_flags & M_EXT) { 1017 n->m_data = m->m_data; 1018 if (m->m_ext.ext_ref == NULL) 1019 atomic_add_char(&mclrefcnt[mtocl(m->m_ext.ext_buf)], 1); 1020 else { 1021 int s = splimp(); 1022 1023 (*m->m_ext.ext_ref)(m->m_ext.ext_buf, 1024 m->m_ext.ext_size); 1025 splx(s); 1026 } 1027 n->m_ext = m->m_ext; 1028 n->m_flags |= M_EXT; 1029 } else { 1030 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat ); 1031 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 1032 } 1033 1034 m = m->m_next; 1035 while (m) { 1036 MGET(o, how, m->m_type); 1037 if (!o) 1038 goto nospace; 1039 1040 n->m_next = o; 1041 n = n->m_next; 1042 1043 n->m_len = m->m_len; 1044 if (m->m_flags & M_EXT) { 1045 n->m_data = m->m_data; 1046 if (m->m_ext.ext_ref == NULL) { 1047 atomic_add_char( 1048 &mclrefcnt[mtocl(m->m_ext.ext_buf)], 1); 1049 } else { 1050 int s = splimp(); 1051 1052 (*m->m_ext.ext_ref)(m->m_ext.ext_buf, 1053 m->m_ext.ext_size); 1054 splx(s); 1055 } 1056 n->m_ext = m->m_ext; 1057 n->m_flags |= M_EXT; 1058 } else { 1059 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 1060 } 1061 1062 m = m->m_next; 1063 } 1064 return top; 1065 nospace: 1066 m_freem(top); 1067 MCFail++; 1068 return 0; 1069 } 1070 1071 /* 1072 * Copy data from an mbuf chain starting "off" bytes from the beginning, 1073 * continuing for "len" bytes, into the indicated buffer. 1074 */ 1075 void 1076 m_copydata(m, off, len, cp) 1077 const struct mbuf *m; 1078 int off; 1079 int len; 1080 caddr_t cp; 1081 { 1082 unsigned count; 1083 1084 KASSERT(off >= 0, ("m_copydata, negative off %d", off)); 1085 KASSERT(len >= 0, ("m_copydata, negative len %d", len)); 1086 while (off > 0) { 1087 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain")); 1088 if (off < m->m_len) 1089 break; 1090 off -= m->m_len; 1091 m = m->m_next; 1092 } 1093 while (len > 0) { 1094 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain")); 1095 count = min(m->m_len - off, len); 1096 bcopy(mtod(m, caddr_t) + off, cp, count); 1097 len -= count; 1098 cp += count; 1099 off = 0; 1100 m = m->m_next; 1101 } 1102 } 1103 1104 /* 1105 * Copy a packet header mbuf chain into a completely new chain, including 1106 * copying any mbuf clusters. Use this instead of m_copypacket() when 1107 * you need a writable copy of an mbuf chain. 1108 */ 1109 struct mbuf * 1110 m_dup(m, how) 1111 struct mbuf *m; 1112 int how; 1113 { 1114 struct mbuf **p, *top = NULL; 1115 int remain, moff, nsize; 1116 1117 /* Sanity check */ 1118 if (m == NULL) 1119 return (0); 1120 KASSERT((m->m_flags & M_PKTHDR) != 0, ("%s: !PKTHDR", __FUNCTION__)); 1121 1122 /* While there's more data, get a new mbuf, tack it on, and fill it */ 1123 remain = m->m_pkthdr.len; 1124 moff = 0; 1125 p = ⊤ 1126 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */ 1127 struct mbuf *n; 1128 1129 /* Get the next new mbuf */ 1130 MGET(n, how, m->m_type); 1131 if (n == NULL) 1132 goto nospace; 1133 if (top == NULL) { /* first one, must be PKTHDR */ 1134 if (!m_dup_pkthdr(n, m, how)) 1135 goto nospace; 1136 nsize = MHLEN; 1137 } else /* not the first one */ 1138 nsize = MLEN; 1139 if (remain >= MINCLSIZE) { 1140 MCLGET(n, how); 1141 if ((n->m_flags & M_EXT) == 0) { 1142 (void)m_free(n); 1143 goto nospace; 1144 } 1145 nsize = MCLBYTES; 1146 } 1147 n->m_len = 0; 1148 1149 /* Link it into the new chain */ 1150 *p = n; 1151 p = &n->m_next; 1152 1153 /* Copy data from original mbuf(s) into new mbuf */ 1154 while (n->m_len < nsize && m != NULL) { 1155 int chunk = min(nsize - n->m_len, m->m_len - moff); 1156 1157 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk); 1158 moff += chunk; 1159 n->m_len += chunk; 1160 remain -= chunk; 1161 if (moff == m->m_len) { 1162 m = m->m_next; 1163 moff = 0; 1164 } 1165 } 1166 1167 /* Check correct total mbuf length */ 1168 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL), 1169 ("%s: bogus m_pkthdr.len", __FUNCTION__)); 1170 } 1171 return (top); 1172 1173 nospace: 1174 m_freem(top); 1175 MCFail++; 1176 return (0); 1177 } 1178 1179 /* 1180 * Concatenate mbuf chain n to m. 1181 * Both chains must be of the same type (e.g. MT_DATA). 1182 * Any m_pkthdr is not updated. 1183 */ 1184 void 1185 m_cat(m, n) 1186 struct mbuf *m, *n; 1187 { 1188 while (m->m_next) 1189 m = m->m_next; 1190 while (n) { 1191 if (m->m_flags & M_EXT || 1192 m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) { 1193 /* just join the two chains */ 1194 m->m_next = n; 1195 return; 1196 } 1197 /* splat the data from one into the other */ 1198 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 1199 (u_int)n->m_len); 1200 m->m_len += n->m_len; 1201 n = m_free(n); 1202 } 1203 } 1204 1205 void 1206 m_adj(mp, req_len) 1207 struct mbuf *mp; 1208 int req_len; 1209 { 1210 int len = req_len; 1211 struct mbuf *m; 1212 int count; 1213 1214 if ((m = mp) == NULL) 1215 return; 1216 if (len >= 0) { 1217 /* 1218 * Trim from head. 1219 */ 1220 while (m != NULL && len > 0) { 1221 if (m->m_len <= len) { 1222 len -= m->m_len; 1223 m->m_len = 0; 1224 m = m->m_next; 1225 } else { 1226 m->m_len -= len; 1227 m->m_data += len; 1228 len = 0; 1229 } 1230 } 1231 m = mp; 1232 if (mp->m_flags & M_PKTHDR) 1233 m->m_pkthdr.len -= (req_len - len); 1234 } else { 1235 /* 1236 * Trim from tail. Scan the mbuf chain, 1237 * calculating its length and finding the last mbuf. 1238 * If the adjustment only affects this mbuf, then just 1239 * adjust and return. Otherwise, rescan and truncate 1240 * after the remaining size. 1241 */ 1242 len = -len; 1243 count = 0; 1244 for (;;) { 1245 count += m->m_len; 1246 if (m->m_next == (struct mbuf *)0) 1247 break; 1248 m = m->m_next; 1249 } 1250 if (m->m_len >= len) { 1251 m->m_len -= len; 1252 if (mp->m_flags & M_PKTHDR) 1253 mp->m_pkthdr.len -= len; 1254 return; 1255 } 1256 count -= len; 1257 if (count < 0) 1258 count = 0; 1259 /* 1260 * Correct length for chain is "count". 1261 * Find the mbuf with last data, adjust its length, 1262 * and toss data from remaining mbufs on chain. 1263 */ 1264 m = mp; 1265 if (m->m_flags & M_PKTHDR) 1266 m->m_pkthdr.len = count; 1267 for (; m; m = m->m_next) { 1268 if (m->m_len >= count) { 1269 m->m_len = count; 1270 break; 1271 } 1272 count -= m->m_len; 1273 } 1274 while (m->m_next) 1275 (m = m->m_next) ->m_len = 0; 1276 } 1277 } 1278 1279 /* 1280 * Rearange an mbuf chain so that len bytes are contiguous 1281 * and in the data area of an mbuf (so that mtod and dtom 1282 * will work for a structure of size len). Returns the resulting 1283 * mbuf chain on success, frees it and returns null on failure. 1284 * If there is room, it will add up to max_protohdr-len extra bytes to the 1285 * contiguous region in an attempt to avoid being called next time. 1286 */ 1287 #define MPFail (mbstat.m_mpfail) 1288 1289 struct mbuf * 1290 m_pullup(n, len) 1291 struct mbuf *n; 1292 int len; 1293 { 1294 struct mbuf *m; 1295 int count; 1296 int space; 1297 1298 /* 1299 * If first mbuf has no cluster, and has room for len bytes 1300 * without shifting current data, pullup into it, 1301 * otherwise allocate a new mbuf to prepend to the chain. 1302 */ 1303 if ((n->m_flags & M_EXT) == 0 && 1304 n->m_data + len < &n->m_dat[MLEN] && n->m_next) { 1305 if (n->m_len >= len) 1306 return (n); 1307 m = n; 1308 n = n->m_next; 1309 len -= m->m_len; 1310 } else { 1311 if (len > MHLEN) 1312 goto bad; 1313 MGET(m, M_DONTWAIT, n->m_type); 1314 if (m == 0) 1315 goto bad; 1316 m->m_len = 0; 1317 if (n->m_flags & M_PKTHDR) 1318 M_MOVE_PKTHDR(m, n); 1319 } 1320 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 1321 do { 1322 count = min(min(max(len, max_protohdr), space), n->m_len); 1323 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 1324 (unsigned)count); 1325 len -= count; 1326 m->m_len += count; 1327 n->m_len -= count; 1328 space -= count; 1329 if (n->m_len) 1330 n->m_data += count; 1331 else 1332 n = m_free(n); 1333 } while (len > 0 && n); 1334 if (len > 0) { 1335 (void) m_free(m); 1336 goto bad; 1337 } 1338 m->m_next = n; 1339 return (m); 1340 bad: 1341 m_freem(n); 1342 MPFail++; 1343 return (0); 1344 } 1345 1346 /* 1347 * Partition an mbuf chain in two pieces, returning the tail -- 1348 * all but the first len0 bytes. In case of failure, it returns NULL and 1349 * attempts to restore the chain to its original state. 1350 * 1351 * Note that the resulting mbufs might be read-only, because the new 1352 * mbuf can end up sharing an mbuf cluster with the original mbuf if 1353 * the "breaking point" happens to lie within a cluster mbuf. Use the 1354 * M_WRITABLE() macro to check for this case. 1355 */ 1356 struct mbuf * 1357 m_split(m0, len0, wait) 1358 struct mbuf *m0; 1359 int len0, wait; 1360 { 1361 struct mbuf *m, *n; 1362 unsigned len = len0, remain; 1363 1364 for (m = m0; m && len > m->m_len; m = m->m_next) 1365 len -= m->m_len; 1366 if (m == 0) 1367 return (0); 1368 remain = m->m_len - len; 1369 if (m0->m_flags & M_PKTHDR) { 1370 MGETHDR(n, wait, m0->m_type); 1371 if (n == 0) 1372 return (0); 1373 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; 1374 n->m_pkthdr.len = m0->m_pkthdr.len - len0; 1375 m0->m_pkthdr.len = len0; 1376 if (m->m_flags & M_EXT) 1377 goto extpacket; 1378 if (remain > MHLEN) { 1379 /* m can't be the lead packet */ 1380 MH_ALIGN(n, 0); 1381 n->m_next = m_split(m, len, wait); 1382 if (n->m_next == 0) { 1383 (void) m_free(n); 1384 return (0); 1385 } else { 1386 n->m_len = 0; 1387 return (n); 1388 } 1389 } else 1390 MH_ALIGN(n, remain); 1391 } else if (remain == 0) { 1392 n = m->m_next; 1393 m->m_next = 0; 1394 return (n); 1395 } else { 1396 MGET(n, wait, m->m_type); 1397 if (n == 0) 1398 return (0); 1399 M_ALIGN(n, remain); 1400 } 1401 extpacket: 1402 if (m->m_flags & M_EXT) { 1403 n->m_flags |= M_EXT; 1404 n->m_ext = m->m_ext; 1405 if (m->m_ext.ext_ref == NULL) 1406 atomic_add_char(&mclrefcnt[mtocl(m->m_ext.ext_buf)], 1); 1407 else { 1408 int s = splimp(); 1409 1410 (*m->m_ext.ext_ref)(m->m_ext.ext_buf, 1411 m->m_ext.ext_size); 1412 splx(s); 1413 } 1414 n->m_data = m->m_data + len; 1415 } else { 1416 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain); 1417 } 1418 n->m_len = remain; 1419 m->m_len = len; 1420 n->m_next = m->m_next; 1421 m->m_next = 0; 1422 return (n); 1423 } 1424 /* 1425 * Routine to copy from device local memory into mbufs. 1426 */ 1427 struct mbuf * 1428 m_devget(buf, totlen, off0, ifp, copy) 1429 char *buf; 1430 int totlen, off0; 1431 struct ifnet *ifp; 1432 void (*copy) (char *from, caddr_t to, u_int len); 1433 { 1434 struct mbuf *m; 1435 struct mbuf *top = 0, **mp = ⊤ 1436 int off = off0, len; 1437 char *cp; 1438 char *epkt; 1439 1440 cp = buf; 1441 epkt = cp + totlen; 1442 if (off) { 1443 cp += off + 2 * sizeof(u_short); 1444 totlen -= 2 * sizeof(u_short); 1445 } 1446 MGETHDR(m, M_DONTWAIT, MT_DATA); 1447 if (m == 0) 1448 return (0); 1449 m->m_pkthdr.rcvif = ifp; 1450 m->m_pkthdr.len = totlen; 1451 m->m_len = MHLEN; 1452 1453 while (totlen > 0) { 1454 if (top) { 1455 MGET(m, M_DONTWAIT, MT_DATA); 1456 if (m == 0) { 1457 m_freem(top); 1458 return (0); 1459 } 1460 m->m_len = MLEN; 1461 } 1462 len = min(totlen, epkt - cp); 1463 if (len >= MINCLSIZE) { 1464 MCLGET(m, M_DONTWAIT); 1465 if (m->m_flags & M_EXT) 1466 m->m_len = len = min(len, MCLBYTES); 1467 else 1468 len = m->m_len; 1469 } else { 1470 /* 1471 * Place initial small packet/header at end of mbuf. 1472 */ 1473 if (len < m->m_len) { 1474 if (top == 0 && len + max_linkhdr <= m->m_len) 1475 m->m_data += max_linkhdr; 1476 m->m_len = len; 1477 } else 1478 len = m->m_len; 1479 } 1480 if (copy) 1481 copy(cp, mtod(m, caddr_t), (unsigned)len); 1482 else 1483 bcopy(cp, mtod(m, caddr_t), (unsigned)len); 1484 cp += len; 1485 *mp = m; 1486 mp = &m->m_next; 1487 totlen -= len; 1488 if (cp == epkt) 1489 cp = buf; 1490 } 1491 return (top); 1492 } 1493 1494 /* 1495 * Copy data from a buffer back into the indicated mbuf chain, 1496 * starting "off" bytes from the beginning, extending the mbuf 1497 * chain if necessary. 1498 */ 1499 void 1500 m_copyback(m0, off, len, cp) 1501 struct mbuf *m0; 1502 int off; 1503 int len; 1504 caddr_t cp; 1505 { 1506 int mlen; 1507 struct mbuf *m = m0, *n; 1508 int totlen = 0; 1509 1510 if (m0 == 0) 1511 return; 1512 while (off > (mlen = m->m_len)) { 1513 off -= mlen; 1514 totlen += mlen; 1515 if (m->m_next == 0) { 1516 n = m_getclr(M_DONTWAIT, m->m_type); 1517 if (n == 0) 1518 goto out; 1519 n->m_len = min(MLEN, len + off); 1520 m->m_next = n; 1521 } 1522 m = m->m_next; 1523 } 1524 while (len > 0) { 1525 mlen = min (m->m_len - off, len); 1526 bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen); 1527 cp += mlen; 1528 len -= mlen; 1529 mlen += off; 1530 off = 0; 1531 totlen += mlen; 1532 if (len == 0) 1533 break; 1534 if (m->m_next == 0) { 1535 n = m_get(M_DONTWAIT, m->m_type); 1536 if (n == 0) 1537 break; 1538 n->m_len = min(MLEN, len); 1539 m->m_next = n; 1540 } 1541 m = m->m_next; 1542 } 1543 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) 1544 m->m_pkthdr.len = totlen; 1545 } 1546 1547 void 1548 m_print(const struct mbuf *m) 1549 { 1550 int len; 1551 const struct mbuf *m2; 1552 1553 len = m->m_pkthdr.len; 1554 m2 = m; 1555 while (len) { 1556 printf("%p %*D\n", m2, m2->m_len, (u_char *)m2->m_data, "-"); 1557 len -= m2->m_len; 1558 m2 = m2->m_next; 1559 } 1560 return; 1561 } 1562 1563 /* 1564 * "Move" mbuf pkthdr from "from" to "to". 1565 * "from" must have M_PKTHDR set, and "to" must be empty. 1566 */ 1567 void 1568 m_move_pkthdr(struct mbuf *to, struct mbuf *from) 1569 { 1570 KASSERT((to->m_flags & M_EXT) == 0, ("m_move_pkthdr: to has cluster")); 1571 1572 to->m_flags = from->m_flags & M_COPYFLAGS; 1573 to->m_data = to->m_pktdat; 1574 to->m_pkthdr = from->m_pkthdr; /* especially tags */ 1575 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */ 1576 from->m_flags &= ~M_PKTHDR; 1577 } 1578 1579 /* 1580 * Duplicate "from"'s mbuf pkthdr in "to". 1581 * "from" must have M_PKTHDR set, and "to" must be empty. 1582 * In particular, this does a deep copy of the packet tags. 1583 */ 1584 int 1585 m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how) 1586 { 1587 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT); 1588 if ((to->m_flags & M_EXT) == 0) 1589 to->m_data = to->m_pktdat; 1590 to->m_pkthdr = from->m_pkthdr; 1591 SLIST_INIT(&to->m_pkthdr.tags); 1592 return (m_tag_copy_chain(to, from, how)); 1593 } 1594 1595 /* 1596 * Defragment a mbuf chain, returning the shortest possible 1597 * chain of mbufs and clusters. If allocation fails and 1598 * this cannot be completed, NULL will be returned, but 1599 * the passed in chain will be unchanged. Upon success, 1600 * the original chain will be freed, and the new chain 1601 * will be returned. 1602 * 1603 * If a non-packet header is passed in, the original 1604 * mbuf (chain?) will be returned unharmed. 1605 */ 1606 struct mbuf * 1607 m_defrag(struct mbuf *m0, int how) 1608 { 1609 struct mbuf *m_new = NULL, *m_final = NULL; 1610 int progress = 0, length; 1611 1612 if (!(m0->m_flags & M_PKTHDR)) 1613 return (m0); 1614 1615 #ifdef MBUF_STRESS_TEST 1616 if (m_defragrandomfailures) { 1617 int temp = arc4random() & 0xff; 1618 if (temp == 0xba) 1619 goto nospace; 1620 } 1621 #endif 1622 1623 if (m0->m_pkthdr.len > MHLEN) 1624 m_final = m_getcl(how, MT_DATA, M_PKTHDR); 1625 else 1626 m_final = m_gethdr(how, MT_DATA); 1627 1628 if (m_final == NULL) 1629 goto nospace; 1630 1631 if (m_dup_pkthdr(m_final, m0, how) == NULL) 1632 goto nospace; 1633 1634 m_new = m_final; 1635 1636 while (progress < m0->m_pkthdr.len) { 1637 length = m0->m_pkthdr.len - progress; 1638 if (length > MCLBYTES) 1639 length = MCLBYTES; 1640 1641 if (m_new == NULL) { 1642 if (length > MLEN) 1643 m_new = m_getcl(how, MT_DATA, 0); 1644 else 1645 m_new = m_get(how, MT_DATA); 1646 if (m_new == NULL) 1647 goto nospace; 1648 } 1649 1650 m_copydata(m0, progress, length, mtod(m_new, caddr_t)); 1651 progress += length; 1652 m_new->m_len = length; 1653 if (m_new != m_final) 1654 m_cat(m_final, m_new); 1655 m_new = NULL; 1656 } 1657 if (m0->m_next == NULL) 1658 m_defraguseless++; 1659 m_freem(m0); 1660 m0 = m_final; 1661 m_defragpackets++; 1662 m_defragbytes += m0->m_pkthdr.len; 1663 return (m0); 1664 nospace: 1665 m_defragfailure++; 1666 if (m_new) 1667 m_free(m_new); 1668 if (m_final) 1669 m_freem(m_final); 1670 return (NULL); 1671 } 1672