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 1.10 2003/07/26 19:42:11 rob 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 __P((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 __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 */ 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 = 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) */ 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 #ifdef __i386__ 404 /* If in interrupt context, and INVARIANTS, maintain sanity and die. */ 405 KASSERT(mycpu->gd_intr_nesting_level == 0, ("CLALLOC: CANNOT WAIT IN INTERRUPT")); 406 #endif 407 408 /* Sleep until something's available or until we expire. */ 409 m_clalloc_wid++; 410 if ((tsleep(&m_clalloc_wid, 0, "mclalc", mbuf_wait)) == EWOULDBLOCK) 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 */ 417 p = m_mclalloc(M_DONTWAIT); 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 */ 435 struct mbuf * 436 m_retry(i, t) 437 int i, t; 438 { 439 struct mbuf *m; 440 int ms; 441 442 /* 443 * Must only do the reclaim if not in an interrupt context. 444 */ 445 if (i == M_WAIT) { 446 #ifdef __i386__ 447 KASSERT(mycpu->gd_intr_nesting_level == 0, 448 ("MBALLOC: CANNOT WAIT IN INTERRUPT")); 449 #endif 450 m_reclaim(); 451 } 452 453 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); 467 mbstat.m_wait++; 468 } else { 469 static int last_report ; /* when we did that (in ticks) */ 470 471 splx(ms); 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 */ 485 struct mbuf * 486 m_retryhdr(i, t) 487 int i, t; 488 { 489 struct mbuf *m; 490 int ms; 491 492 /* 493 * Must only do the reclaim if not in an interrupt context. 494 */ 495 if (i == M_WAIT) { 496 #ifdef __i386__ 497 KASSERT(mycpu->gd_intr_nesting_level == 0, 498 ("MBALLOC: CANNOT WAIT IN INTERRUPT")); 499 #endif 500 m_reclaim(); 501 } 502 503 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); 520 mbstat.m_wait++; 521 } else { 522 static int last_report ; /* when we did that (in ticks) */ 523 524 splx(ms); 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 } 534 535 static void 536 m_reclaim() 537 { 538 struct domain *dp; 539 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 */ 555 struct mbuf * 556 m_get(how, type) 557 int how, type; 558 { 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 } 582 return (m); 583 } 584 585 struct mbuf * 586 m_gethdr(how, type) 587 int how, type; 588 { 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 } 615 return (m); 616 } 617 618 struct mbuf * 619 m_getclr(how, type) 620 int how, type; 621 { 622 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 */ 641 static struct mbuf *mcl_pool; 642 static int mcl_pool_now; 643 static int mcl_pool_max = 0; 644 645 SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_pool_max, CTLFLAG_RW, &mcl_pool_max, 0, 646 "Maximum number of mbufs+cluster in free list"); 647 SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_pool_now, CTLFLAG_RD, &mcl_pool_now, 0, 648 "Current number of mbufs+cluster in free list"); 649 650 struct mbuf * 651 m_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 */ 697 struct mbuf * 698 m_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); 743 744 failed: 745 m_freem(top); 746 return (NULL); 747 } 748 749 /* 750 * m_mclalloc() - Allocates an mbuf cluster. 751 */ 752 caddr_t 753 m_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 */ 779 void 780 m_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 } 791 792 static __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 } 805 806 void 807 m_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. 819 * 820 * We do need to check non-first mbuf for m_aux, since some of existing 821 * code does not call M_PREPEND properly. 822 * (example: call to bpf_mtap from drivers) 823 */ 824 struct mbuf * 825 m_free(struct mbuf *m) 826 { 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); 849 850 return (n); 851 } 852 853 void 854 m_freem(struct mbuf *m) 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 */ 891 struct mbuf * 892 m_prepend(m, len, how) 893 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) 921 922 struct mbuf * 923 m_copym(m, off0, len, wait) 924 const struct mbuf *m; 925 int off0, wait; 926 int len; 927 { 928 struct mbuf *n, **np; 929 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 = ⊤ 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); 992 nospace: 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 */ 1007 struct mbuf * 1008 m_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; 1071 nospace: 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 */ 1081 void 1082 m_copydata(m, off, len, cp) 1083 const struct mbuf *m; 1084 int off; 1085 int len; 1086 caddr_t cp; 1087 { 1088 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 */ 1115 struct mbuf * 1116 m_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 = ⊤ 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 1179 nospace: 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 */ 1190 void 1191 m_cat(m, n) 1192 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 1211 void 1212 m_adj(mp, req_len) 1213 struct mbuf *mp; 1214 int req_len; 1215 { 1216 int len = req_len; 1217 struct mbuf *m; 1218 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 1295 struct mbuf * 1296 m_pullup(n, len) 1297 struct mbuf *n; 1298 int len; 1299 { 1300 struct mbuf *m; 1301 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); 1346 bad: 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 */ 1362 struct mbuf * 1363 m_split(m0, len0, wait) 1364 struct mbuf *m0; 1365 int len0, wait; 1366 { 1367 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 } 1407 extpacket: 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 */ 1433 struct mbuf * 1434 m_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 struct mbuf *m; 1441 struct mbuf *top = 0, **mp = ⊤ 1442 int off = off0, len; 1443 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 */ 1505 void 1506 m_copyback(m0, off, len, cp) 1507 struct mbuf *m0; 1508 int off; 1509 int len; 1510 caddr_t cp; 1511 { 1512 int mlen; 1513 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 } 1549 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) 1550 m->m_pkthdr.len = totlen; 1551 } 1552 1553 void 1554 m_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 */ 1573 void 1574 m_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 */ 1590 int 1591 m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how) 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 */ 1612 struct mbuf * 1613 m_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); 1670 nospace: 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 } 1678