1 /* 2 * Copyright (c) 2004 Jeffrey M. Hsu. All rights reserved. 3 * Copyright (c) 2004 The DragonFly Project. All rights reserved. 4 * 5 * This code is derived from software contributed to The DragonFly Project 6 * by Jeffrey M. Hsu. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of The DragonFly Project nor the names of its 17 * contributors may be used to endorse or promote products derived 18 * from this software without specific, prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 /* 35 * Copyright (c) 2004 Jeffrey M. Hsu. All rights reserved. 36 * 37 * License terms: all terms for the DragonFly license above plus the following: 38 * 39 * 4. All advertising materials mentioning features or use of this software 40 * must display the following acknowledgement: 41 * 42 * This product includes software developed by Jeffrey M. Hsu 43 * for the DragonFly Project. 44 * 45 * This requirement may be waived with permission from Jeffrey Hsu. 46 * This requirement will sunset and may be removed on July 8 2005, 47 * after which the standard DragonFly license (as shown above) will 48 * apply. 49 */ 50 51 /* 52 * Copyright (c) 1982, 1986, 1988, 1991, 1993 53 * The Regents of the University of California. All rights reserved. 54 * 55 * Redistribution and use in source and binary forms, with or without 56 * modification, are permitted provided that the following conditions 57 * are met: 58 * 1. Redistributions of source code must retain the above copyright 59 * notice, this list of conditions and the following disclaimer. 60 * 2. Redistributions in binary form must reproduce the above copyright 61 * notice, this list of conditions and the following disclaimer in the 62 * documentation and/or other materials provided with the distribution. 63 * 3. All advertising materials mentioning features or use of this software 64 * must display the following acknowledgement: 65 * This product includes software developed by the University of 66 * California, Berkeley and its contributors. 67 * 4. Neither the name of the University nor the names of its contributors 68 * may be used to endorse or promote products derived from this software 69 * without specific prior written permission. 70 * 71 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 72 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 73 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 74 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 75 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 76 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 77 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 78 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 79 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 80 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 81 * SUCH DAMAGE. 82 * 83 * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94 84 * $FreeBSD: src/sys/kern/uipc_mbuf.c,v 1.51.2.24 2003/04/15 06:59:29 silby Exp $ 85 * $DragonFly: src/sys/kern/uipc_mbuf.c,v 1.40 2005/05/31 14:11:43 joerg Exp $ 86 */ 87 88 #include "opt_param.h" 89 #include "opt_mbuf_stress_test.h" 90 #include <sys/param.h> 91 #include <sys/systm.h> 92 #include <sys/malloc.h> 93 #include <sys/mbuf.h> 94 #include <sys/kernel.h> 95 #include <sys/sysctl.h> 96 #include <sys/domain.h> 97 #include <sys/protosw.h> 98 #include <sys/uio.h> 99 #include <sys/thread.h> 100 #include <sys/globaldata.h> 101 #include <sys/thread2.h> 102 103 #include <vm/vm.h> 104 #include <vm/vm_kern.h> 105 #include <vm/vm_extern.h> 106 107 #ifdef INVARIANTS 108 #include <machine/cpu.h> 109 #endif 110 111 /* 112 * mbuf cluster meta-data 113 */ 114 typedef struct mbcluster { 115 struct mbcluster *mcl_next; 116 int32_t mcl_magic; 117 int32_t mcl_refs; 118 void *mcl_data; 119 } *mbcluster_t; 120 121 typedef struct mbuf *mbuf_t; 122 123 #define MCL_MAGIC 0x6d62636c 124 125 static void mbinit (void *); 126 SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL) 127 128 static u_long mbtypes[MT_NTYPES]; 129 130 struct mbstat mbstat; 131 int max_linkhdr; 132 int max_protohdr; 133 int max_hdr; 134 int max_datalen; 135 int m_defragpackets; 136 int m_defragbytes; 137 int m_defraguseless; 138 int m_defragfailure; 139 #ifdef MBUF_STRESS_TEST 140 int m_defragrandomfailures; 141 #endif 142 143 int nmbclusters; 144 int nmbufs; 145 u_int m_mballoc_wid = 0; 146 u_int m_clalloc_wid = 0; 147 148 SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW, 149 &max_linkhdr, 0, ""); 150 SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW, 151 &max_protohdr, 0, ""); 152 SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0, ""); 153 SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW, 154 &max_datalen, 0, ""); 155 SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_wait, CTLFLAG_RW, 156 &mbuf_wait, 0, ""); 157 SYSCTL_STRUCT(_kern_ipc, KIPC_MBSTAT, mbstat, CTLFLAG_RW, &mbstat, mbstat, ""); 158 SYSCTL_OPAQUE(_kern_ipc, OID_AUTO, mbtypes, CTLFLAG_RD, mbtypes, 159 sizeof(mbtypes), "LU", ""); 160 SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters, CTLFLAG_RW, 161 &nmbclusters, 0, "Maximum number of mbuf clusters available"); 162 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbufs, CTLFLAG_RW, &nmbufs, 0, 163 "Maximum number of mbufs available"); 164 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD, 165 &m_defragpackets, 0, ""); 166 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD, 167 &m_defragbytes, 0, ""); 168 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD, 169 &m_defraguseless, 0, ""); 170 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD, 171 &m_defragfailure, 0, ""); 172 #ifdef MBUF_STRESS_TEST 173 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW, 174 &m_defragrandomfailures, 0, ""); 175 #endif 176 177 static int mcl_pool_count; 178 static int mcl_pool_max = 20; 179 static int mcl_free_max = 1000; 180 static int mbuf_free_max = 5000; 181 182 SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_pool_max, CTLFLAG_RW, &mcl_pool_max, 0, 183 "Maximum number of mbufs+cluster in free list"); 184 SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_pool_count, CTLFLAG_RD, &mcl_pool_count, 0, 185 "Current number of mbufs+cluster in free list"); 186 SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_free_max, CTLFLAG_RW, &mcl_free_max, 0, 187 "Maximum number of clusters on the free list"); 188 SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_free_max, CTLFLAG_RW, &mbuf_free_max, 0, 189 "Maximum number of mbufs on the free list"); 190 191 static MALLOC_DEFINE(M_MBUF, "mbuf", "mbuf"); 192 static MALLOC_DEFINE(M_MBUFCL, "mbufcl", "mbufcl"); 193 194 static mbuf_t mmbfree; 195 static mbcluster_t mclfree; 196 static struct mbuf *mcl_pool; 197 198 static void m_reclaim (void); 199 static int m_mballoc(int nmb, int how); 200 static int m_clalloc(int ncl, int how); 201 static struct mbuf *m_mballoc_wait(int caller, int type); 202 static void m_mclref(void *arg); 203 static void m_mclfree(void *arg); 204 205 #ifndef NMBCLUSTERS 206 #define NMBCLUSTERS (512 + maxusers * 16) 207 #endif 208 #ifndef NMBUFS 209 #define NMBUFS (nmbclusters * 4) 210 #endif 211 212 /* 213 * Perform sanity checks of tunables declared above. 214 */ 215 static void 216 tunable_mbinit(void *dummy) 217 { 218 219 /* 220 * This has to be done before VM init. 221 */ 222 nmbclusters = NMBCLUSTERS; 223 TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters); 224 nmbufs = NMBUFS; 225 TUNABLE_INT_FETCH("kern.ipc.nmbufs", &nmbufs); 226 /* Sanity checks */ 227 if (nmbufs < nmbclusters * 2) 228 nmbufs = nmbclusters * 2; 229 230 return; 231 } 232 SYSINIT(tunable_mbinit, SI_SUB_TUNABLES, SI_ORDER_ANY, tunable_mbinit, NULL); 233 234 /* "number of clusters of pages" */ 235 #define NCL_INIT 1 236 237 #define NMB_INIT 16 238 239 /* ARGSUSED*/ 240 static void 241 mbinit(void *dummy) 242 { 243 mmbfree = NULL; 244 mclfree = NULL; 245 mbstat.m_msize = MSIZE; 246 mbstat.m_mclbytes = MCLBYTES; 247 mbstat.m_minclsize = MINCLSIZE; 248 mbstat.m_mlen = MLEN; 249 mbstat.m_mhlen = MHLEN; 250 251 crit_enter(); 252 if (m_mballoc(NMB_INIT, MB_DONTWAIT) == 0) 253 goto bad; 254 #if MCLBYTES <= PAGE_SIZE 255 if (m_clalloc(NCL_INIT, MB_DONTWAIT) == 0) 256 goto bad; 257 #else 258 /* It's OK to call contigmalloc in this context. */ 259 if (m_clalloc(16, MB_WAIT) == 0) 260 goto bad; 261 #endif 262 crit_exit(); 263 return; 264 bad: 265 crit_exit(); 266 panic("mbinit"); 267 } 268 269 /* 270 * Allocate at least nmb mbufs and place on mbuf free list. 271 * Returns the number of mbufs successfully allocated, 0 if none. 272 * 273 * Must be called while in a critical section. 274 */ 275 static int 276 m_mballoc(int nmb, int how) 277 { 278 int i; 279 struct mbuf *m; 280 281 /* 282 * If we've hit the mbuf limit, stop allocating (or trying to) 283 * in order to avoid exhausting kernel memory entirely. 284 */ 285 if ((nmb + mbstat.m_mbufs) > nmbufs) 286 return (0); 287 288 /* 289 * Attempt to allocate the requested number of mbufs, terminate when 290 * the allocation fails but if blocking is allowed allocate at least 291 * one. 292 */ 293 for (i = 0; i < nmb; ++i) { 294 m = malloc(MSIZE, M_MBUF, M_NOWAIT|M_NULLOK|M_ZERO); 295 if (m == NULL) { 296 if (how == MB_WAIT) { 297 mbstat.m_wait++; 298 m = malloc(MSIZE, M_MBUF, 299 M_WAITOK|M_NULLOK|M_ZERO); 300 } 301 if (m == NULL) 302 break; 303 } 304 m->m_next = mmbfree; 305 mmbfree = m; 306 ++mbstat.m_mbufs; 307 ++mbtypes[MT_FREE]; 308 how = MB_DONTWAIT; 309 } 310 return(i); 311 } 312 313 /* 314 * Once mbuf memory has been exhausted and if the call to the allocation macros 315 * (or, in some cases, functions) is with MB_WAIT, then it is necessary to rely 316 * solely on reclaimed mbufs. Here we wait for an mbuf to be freed for a 317 * designated (mbuf_wait) time. 318 */ 319 static struct mbuf * 320 m_mballoc_wait(int caller, int type) 321 { 322 struct mbuf *m; 323 324 crit_enter(); 325 m_mballoc_wid++; 326 if ((tsleep(&m_mballoc_wid, 0, "mballc", mbuf_wait)) == EWOULDBLOCK) 327 m_mballoc_wid--; 328 crit_exit(); 329 330 /* 331 * Now that we (think) that we've got something, we will redo an 332 * MGET, but avoid getting into another instance of m_mballoc_wait() 333 * XXX: We retry to fetch _even_ if the sleep timed out. This is left 334 * this way, purposely, in the [unlikely] case that an mbuf was 335 * freed but the sleep was not awakened in time. 336 */ 337 m = NULL; 338 switch (caller) { 339 case MGET_C: 340 MGET(m, MB_DONTWAIT, type); 341 break; 342 case MGETHDR_C: 343 MGETHDR(m, MB_DONTWAIT, type); 344 break; 345 default: 346 panic("m_mballoc_wait: invalid caller (%d)", caller); 347 } 348 349 crit_enter(); 350 if (m != NULL) { /* We waited and got something... */ 351 mbstat.m_wait++; 352 /* Wake up another if we have more free. */ 353 if (mmbfree != NULL) 354 MMBWAKEUP(); 355 } 356 crit_exit(); 357 return (m); 358 } 359 360 #if MCLBYTES > PAGE_SIZE 361 static int i_want_my_mcl; 362 363 static void 364 kproc_mclalloc(void) 365 { 366 int status; 367 368 crit_enter(); 369 for (;;) { 370 tsleep(&i_want_my_mcl, 0, "mclalloc", 0); 371 372 while (i_want_my_mcl > 0) { 373 if (m_clalloc(1, MB_WAIT) == 0) 374 printf("m_clalloc failed even in thread context!\n"); 375 --i_want_my_mcl; 376 } 377 } 378 /* not reached */ 379 crit_exit(); 380 } 381 382 static struct thread *mclallocthread; 383 static struct kproc_desc mclalloc_kp = { 384 "mclalloc", 385 kproc_mclalloc, 386 &mclallocthread 387 }; 388 SYSINIT(mclallocthread, SI_SUB_KTHREAD_UPDATE, SI_ORDER_ANY, kproc_start, 389 &mclalloc_kp); 390 #endif 391 392 /* 393 * Allocate at least nmb mbuf clusters and place on mbuf free list. 394 * Returns the number of mbuf clusters successfully allocated, 0 if none. 395 * 396 * Must be called while in a critical section. 397 */ 398 static int 399 m_clalloc(int ncl, int how) 400 { 401 static int last_report; 402 mbcluster_t mcl; 403 void *data; 404 int i; 405 406 /* 407 * If we've hit the mbuf cluster limit, stop allocating (or trying to). 408 */ 409 if ((ncl + mbstat.m_clusters) > nmbclusters) 410 ncl = 0; 411 412 /* 413 * Attempt to allocate the requested number of mbuf clusters, 414 * terminate when the allocation fails but if blocking is allowed 415 * allocate at least one. 416 * 417 * We need to allocate two structures for each cluster... a 418 * ref counting / governing structure and the actual data. MCLBYTES 419 * should be a power of 2 which means that the slab allocator will 420 * return a buffer that does not cross a page boundary. 421 */ 422 for (i = 0; i < ncl; ++i) { 423 /* 424 * Meta structure 425 */ 426 mcl = malloc(sizeof(*mcl), M_MBUFCL, M_NOWAIT|M_NULLOK|M_ZERO); 427 if (mcl == NULL) { 428 if (how == MB_WAIT) { 429 mbstat.m_wait++; 430 mcl = malloc(sizeof(*mcl), 431 M_MBUFCL, M_WAITOK|M_NULLOK|M_ZERO); 432 } 433 if (mcl == NULL) 434 break; 435 } 436 437 /* 438 * Physically contiguous data buffer. 439 */ 440 #if MCLBYTES > PAGE_SIZE 441 if (how != MB_WAIT) { 442 i_want_my_mcl += ncl - i; 443 wakeup(&i_want_my_mcl); 444 mbstat.m_wait++; 445 data = NULL; 446 } else { 447 data = contigmalloc_map(MCLBYTES, M_MBUFCL, 448 M_WAITOK, 0ul, ~0ul, PAGE_SIZE, 0, kernel_map); 449 } 450 #else 451 data = malloc(MCLBYTES, M_MBUFCL, M_NOWAIT|M_NULLOK); 452 if (data == NULL) { 453 if (how == MB_WAIT) { 454 mbstat.m_wait++; 455 data = malloc(MCLBYTES, M_MBUFCL, 456 M_WAITOK|M_NULLOK); 457 } 458 } 459 #endif 460 if (data == NULL) { 461 free(mcl, M_MBUFCL); 462 break; 463 } 464 mcl->mcl_next = mclfree; 465 mcl->mcl_data = data; 466 mcl->mcl_magic = MCL_MAGIC; 467 mcl->mcl_refs = 0; 468 mclfree = mcl; 469 ++mbstat.m_clfree; 470 ++mbstat.m_clusters; 471 how = MB_DONTWAIT; 472 } 473 474 /* 475 * If we could not allocate any report failure no more often then 476 * once a second. 477 */ 478 if (i == 0) { 479 mbstat.m_drops++; 480 if (ticks < last_report || (ticks - last_report) >= hz) { 481 last_report = ticks; 482 printf("All mbuf clusters exhausted, please see tuning(7).\n"); 483 } 484 } 485 return (i); 486 } 487 488 /* 489 * Once cluster memory has been exhausted and the allocation is called with 490 * MB_WAIT, we rely on the mclfree pointers. If nothing is free, we will 491 * sleep for a designated amount of time (mbuf_wait) or until we're woken up 492 * due to sudden mcluster availability. 493 * 494 * Must be called while in a critical section. 495 */ 496 static void 497 m_clalloc_wait(void) 498 { 499 /* If in interrupt context, and INVARIANTS, maintain sanity and die. */ 500 KASSERT(mycpu->gd_intr_nesting_level == 0, 501 ("CLALLOC: CANNOT WAIT IN INTERRUPT")); 502 503 /* 504 * Sleep until something's available or until we expire. 505 */ 506 m_clalloc_wid++; 507 if ((tsleep(&m_clalloc_wid, 0, "mclalc", mbuf_wait)) == EWOULDBLOCK) 508 m_clalloc_wid--; 509 510 /* 511 * Try the allocation once more, and if we see mor then two 512 * free entries wake up others as well. 513 */ 514 m_clalloc(1, MB_WAIT); 515 if (mclfree && mclfree->mcl_next) { 516 MCLWAKEUP(); 517 } 518 } 519 520 /* 521 * Return the number of references to this mbuf's data. 0 is returned 522 * if the mbuf is not M_EXT, a reference count is returned if it is 523 * M_EXT|M_EXT_CLUSTER, and 99 is returned if it is a special M_EXT. 524 */ 525 int 526 m_sharecount(struct mbuf *m) 527 { 528 int count; 529 530 switch(m->m_flags & (M_EXT|M_EXT_CLUSTER)) { 531 case 0: 532 count = 0; 533 break; 534 case M_EXT: 535 count = 99; 536 break; 537 case M_EXT|M_EXT_CLUSTER: 538 count = ((mbcluster_t)m->m_ext.ext_arg)->mcl_refs; 539 break; 540 default: 541 panic("bad mbuf flags: %p", m); 542 count = 0; 543 } 544 return(count); 545 } 546 547 /* 548 * change mbuf to new type 549 */ 550 void 551 m_chtype(struct mbuf *m, int type) 552 { 553 crit_enter(); 554 --mbtypes[m->m_type]; 555 ++mbtypes[type]; 556 m->m_type = type; 557 crit_exit(); 558 } 559 560 /* 561 * When MGET fails, ask protocols to free space when short of memory, 562 * then re-attempt to allocate an mbuf. 563 */ 564 struct mbuf * 565 m_retry(int how, int t) 566 { 567 struct mbuf *m; 568 569 /* 570 * Must only do the reclaim if not in an interrupt context. 571 */ 572 if (how == MB_WAIT) { 573 KASSERT(mycpu->gd_intr_nesting_level == 0, 574 ("MBALLOC: CANNOT WAIT IN INTERRUPT")); 575 m_reclaim(); 576 } 577 578 /* 579 * Try to pull a new mbuf out of the cache, if the cache is empty 580 * try to allocate a new one and if that doesn't work we give up. 581 */ 582 crit_enter(); 583 if ((m = mmbfree) == NULL) { 584 m_mballoc(1, how); 585 if ((m = mmbfree) == NULL) { 586 static int last_report; 587 588 mbstat.m_drops++; 589 crit_exit(); 590 if (ticks < last_report || 591 (ticks - last_report) >= hz) { 592 last_report = ticks; 593 printf("All mbufs exhausted, please see tuning(7).\n"); 594 } 595 return (NULL); 596 } 597 } 598 599 /* 600 * Cache case, adjust globals before leaving the critical section 601 */ 602 mmbfree = m->m_next; 603 mbtypes[MT_FREE]--; 604 mbtypes[t]++; 605 mbstat.m_wait++; 606 crit_exit(); 607 608 m->m_type = t; 609 m->m_next = NULL; 610 m->m_nextpkt = NULL; 611 m->m_data = m->m_dat; 612 m->m_flags = 0; 613 return (m); 614 } 615 616 /* 617 * As above; retry an MGETHDR. 618 */ 619 struct mbuf * 620 m_retryhdr(int how, int t) 621 { 622 struct mbuf *m; 623 624 /* 625 * Must only do the reclaim if not in an interrupt context. 626 */ 627 if (how == MB_WAIT) { 628 KASSERT(mycpu->gd_intr_nesting_level == 0, 629 ("MBALLOC: CANNOT WAIT IN INTERRUPT")); 630 m_reclaim(); 631 } 632 633 /* 634 * Try to pull a new mbuf out of the cache, if the cache is empty 635 * try to allocate a new one and if that doesn't work we give up. 636 */ 637 crit_enter(); 638 if ((m = mmbfree) == NULL) { 639 m_mballoc(1, how); 640 if ((m = mmbfree) == NULL) { 641 static int last_report; 642 643 mbstat.m_drops++; 644 crit_exit(); 645 if (ticks < last_report || 646 (ticks - last_report) >= hz) { 647 last_report = ticks; 648 printf("All mbufs exhausted, please see tuning(7).\n"); 649 } 650 return (NULL); 651 } 652 } 653 654 /* 655 * Cache case, adjust globals before leaving the critical section 656 */ 657 mmbfree = m->m_next; 658 mbtypes[MT_FREE]--; 659 mbtypes[t]++; 660 mbstat.m_wait++; 661 crit_exit(); 662 663 m->m_type = t; 664 m->m_next = NULL; 665 m->m_nextpkt = NULL; 666 m->m_data = m->m_pktdat; 667 m->m_flags = M_PKTHDR; 668 m->m_pkthdr.rcvif = NULL; 669 SLIST_INIT(&m->m_pkthdr.tags); 670 m->m_pkthdr.csum_flags = 0; 671 return (m); 672 } 673 674 static void 675 m_reclaim(void) 676 { 677 struct domain *dp; 678 struct protosw *pr; 679 680 crit_enter(); 681 SLIST_FOREACH(dp, &domains, dom_next) { 682 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) { 683 if (pr->pr_drain) 684 (*pr->pr_drain)(); 685 } 686 } 687 crit_exit(); 688 mbstat.m_drain++; 689 } 690 691 /* 692 * Allocate an mbuf. If no mbufs are immediately available try to 693 * bring a bunch more into our cache (mmbfree list). A critical 694 * section is required to protect the mmbfree list and counters 695 * against interrupts. 696 */ 697 struct mbuf * 698 m_get(int how, int type) 699 { 700 struct mbuf *m; 701 702 /* 703 * Try to pull a new mbuf out of the cache, if the cache is empty 704 * try to allocate a new one and if that doesn't work try even harder 705 * by calling m_retryhdr(). 706 */ 707 crit_enter(); 708 if ((m = mmbfree) == NULL) { 709 m_mballoc(1, how); 710 if ((m = mmbfree) == NULL) { 711 crit_exit(); 712 m = m_retry(how, type); 713 if (m == NULL && how == MB_WAIT) 714 m = m_mballoc_wait(MGET_C, type); 715 return (m); 716 } 717 } 718 719 /* 720 * Cache case, adjust globals before leaving the critical section 721 */ 722 mmbfree = m->m_next; 723 mbtypes[MT_FREE]--; 724 mbtypes[type]++; 725 crit_exit(); 726 727 m->m_type = type; 728 m->m_next = NULL; 729 m->m_nextpkt = NULL; 730 m->m_data = m->m_dat; 731 m->m_flags = 0; 732 return (m); 733 } 734 735 struct mbuf * 736 m_gethdr(int how, int type) 737 { 738 struct mbuf *m; 739 740 /* 741 * Try to pull a new mbuf out of the cache, if the cache is empty 742 * try to allocate a new one and if that doesn't work try even harder 743 * by calling m_retryhdr(). 744 */ 745 crit_enter(); 746 if ((m = mmbfree) == NULL) { 747 m_mballoc(1, how); 748 if ((m = mmbfree) == NULL) { 749 crit_exit(); 750 m = m_retryhdr(how, type); 751 if (m == NULL && how == MB_WAIT) 752 m = m_mballoc_wait(MGETHDR_C, type); 753 return(m); 754 } 755 } 756 757 /* 758 * Cache case, adjust globals before leaving the critical section 759 */ 760 mmbfree = m->m_next; 761 mbtypes[MT_FREE]--; 762 mbtypes[type]++; 763 crit_exit(); 764 765 m->m_type = type; 766 m->m_next = NULL; 767 m->m_nextpkt = NULL; 768 m->m_data = m->m_pktdat; 769 m->m_flags = M_PKTHDR; 770 m->m_pkthdr.rcvif = NULL; 771 SLIST_INIT(&m->m_pkthdr.tags); 772 m->m_pkthdr.csum_flags = 0; 773 m->m_pkthdr.fw_flags = 0; 774 return (m); 775 } 776 777 struct mbuf * 778 m_getclr(int how, int type) 779 { 780 struct mbuf *m; 781 782 if ((m = m_get(how, type)) != NULL) { 783 bzero(mtod(m, caddr_t), MLEN); 784 } 785 return (m); 786 } 787 788 /* 789 * m_getcl() returns an mbuf with an attached cluster. 790 * Because many network drivers use this kind of buffers a lot, it is 791 * convenient to keep a small pool of free buffers of this kind. 792 * Even a small size such as 10 gives about 10% improvement in the 793 * forwarding rate in a bridge or router. 794 * The size of this free list is controlled by the sysctl variable 795 * mcl_pool_max. The list is populated on m_freem(), and used in 796 * m_getcl() if elements are available. 797 */ 798 struct mbuf * 799 m_getcl(int how, short type, int flags) 800 { 801 struct mbuf *mp; 802 803 crit_enter(); 804 if (flags & M_PKTHDR) { 805 if (type == MT_DATA && mcl_pool) { 806 mp = mcl_pool; 807 mcl_pool = mp->m_nextpkt; 808 --mcl_pool_count; 809 crit_exit(); 810 mp->m_nextpkt = NULL; 811 mp->m_data = mp->m_ext.ext_buf; 812 mp->m_flags = M_PKTHDR|M_EXT|M_EXT_CLUSTER; 813 mp->m_pkthdr.rcvif = NULL; 814 mp->m_pkthdr.csum_flags = 0; 815 return mp; 816 } 817 MGETHDR(mp, how, type); 818 } else { 819 MGET(mp, how, type); 820 } 821 if (mp) { 822 m_mclget(mp, how); 823 if ((mp->m_flags & M_EXT) == 0) { 824 m_free(mp); 825 mp = NULL; 826 } 827 } 828 crit_exit(); 829 return (mp); 830 } 831 832 /* 833 * Allocate chain of requested length. 834 */ 835 struct mbuf * 836 m_getc(int len, int how, int type) 837 { 838 struct mbuf *n, *nfirst = NULL, **ntail = &nfirst; 839 int nsize; 840 841 while (len > 0) { 842 n = m_getl(len, how, type, 0, &nsize); 843 if (n == NULL) 844 goto failed; 845 n->m_len = 0; 846 *ntail = n; 847 ntail = &n->m_next; 848 len -= nsize; 849 } 850 return (nfirst); 851 852 failed: 853 m_freem(nfirst); 854 return (NULL); 855 } 856 857 /* 858 * Allocate len-worth of mbufs and/or mbuf clusters (whatever fits best) 859 * and return a pointer to the head of the allocated chain. If m0 is 860 * non-null, then we assume that it is a single mbuf or an mbuf chain to 861 * which we want len bytes worth of mbufs and/or clusters attached, and so 862 * if we succeed in allocating it, we will just return a pointer to m0. 863 * 864 * If we happen to fail at any point during the allocation, we will free 865 * up everything we have already allocated and return NULL. 866 * 867 * Deprecated. Use m_getc() and m_cat() instead. 868 */ 869 struct mbuf * 870 m_getm(struct mbuf *m0, int len, int how, int type) 871 { 872 struct mbuf *nfirst; 873 874 nfirst = m_getc(len, how, type); 875 876 if (m0 != NULL) { 877 m_last(m0)->m_next = nfirst; 878 return (m0); 879 } 880 881 return (nfirst); 882 } 883 884 /* 885 * m_mclget() - Adds a cluster to a normal mbuf, M_EXT is set on success. 886 */ 887 void 888 m_mclget(struct mbuf *m, int how) 889 { 890 mbcluster_t mcl; 891 892 /* 893 * Allocate a cluster, return if we can't get one. 894 */ 895 crit_enter(); 896 if ((mcl = mclfree) == NULL) { 897 m_clalloc(1, how); 898 if ((mcl = mclfree) == NULL) { 899 if (how == MB_WAIT) { 900 m_clalloc_wait(); 901 mcl = mclfree; 902 } 903 if (mcl == NULL) { 904 crit_exit(); 905 return; 906 } 907 } 908 } 909 910 /* 911 * We have a cluster, unlink it from the free list and set the ref 912 * count. 913 */ 914 KKASSERT(mcl->mcl_refs == 0); 915 mclfree = mcl->mcl_next; 916 mcl->mcl_refs = 1; 917 --mbstat.m_clfree; 918 crit_exit(); 919 920 /* 921 * Add the cluster to the mbuf. The caller will detect that the 922 * mbuf now has an attached cluster. 923 */ 924 m->m_ext.ext_arg = mcl; 925 m->m_ext.ext_buf = mcl->mcl_data; 926 m->m_ext.ext_ref = m_mclref; 927 m->m_ext.ext_free = m_mclfree; 928 m->m_ext.ext_size = MCLBYTES; 929 930 m->m_data = m->m_ext.ext_buf; 931 m->m_flags |= M_EXT | M_EXT_CLUSTER; 932 } 933 934 static void 935 m_mclfree(void *arg) 936 { 937 mbcluster_t mcl = arg; 938 939 KKASSERT(mcl->mcl_magic == MCL_MAGIC); 940 KKASSERT(mcl->mcl_refs > 0); 941 crit_enter(); 942 if (--mcl->mcl_refs == 0) { 943 if (mbstat.m_clfree < mcl_free_max) { 944 mcl->mcl_next = mclfree; 945 mclfree = mcl; 946 ++mbstat.m_clfree; 947 MCLWAKEUP(); 948 } else { 949 mcl->mcl_magic = -1; 950 free(mcl->mcl_data, M_MBUFCL); 951 free(mcl, M_MBUFCL); 952 --mbstat.m_clusters; 953 } 954 } 955 crit_exit(); 956 } 957 958 static void 959 m_mclref(void *arg) 960 { 961 mbcluster_t mcl = arg; 962 963 KKASSERT(mcl->mcl_magic == MCL_MAGIC); 964 crit_enter(); 965 ++mcl->mcl_refs; 966 crit_exit(); 967 } 968 969 /* 970 * Helper routines for M_EXT reference/free 971 */ 972 static __inline void 973 m_extref(const struct mbuf *m) 974 { 975 KKASSERT(m->m_ext.ext_free != NULL); 976 crit_enter(); 977 m->m_ext.ext_ref(m->m_ext.ext_arg); 978 crit_exit(); 979 } 980 981 /* 982 * m_free() 983 * 984 * Free a single mbuf and any associated external storage. The successor, 985 * if any, is returned. 986 * 987 * We do need to check non-first mbuf for m_aux, since some of existing 988 * code does not call M_PREPEND properly. 989 * (example: call to bpf_mtap from drivers) 990 */ 991 struct mbuf * 992 m_free(struct mbuf *m) 993 { 994 struct mbuf *n; 995 996 crit_enter(); 997 KASSERT(m->m_type != MT_FREE, ("freeing free mbuf %p", m)); 998 999 /* 1000 * Adjust our type count and delete any attached chains if the 1001 * mbuf is a packet header. 1002 */ 1003 if ((m->m_flags & M_PKTHDR) != 0) 1004 m_tag_delete_chain(m, NULL); 1005 1006 /* 1007 * Place the mbuf on the appropriate free list. Try to maintain a 1008 * small cache of mbuf+cluster pairs. 1009 */ 1010 n = m->m_next; 1011 m->m_next = NULL; 1012 if (m->m_flags & M_EXT) { 1013 KKASSERT(m->m_ext.ext_free != NULL); 1014 if (mcl_pool_count < mcl_pool_max && m && m->m_next == NULL && 1015 (m->m_flags & (M_PKTHDR|M_EXT_CLUSTER)) == (M_PKTHDR|M_EXT_CLUSTER) && 1016 m->m_type == MT_DATA && M_EXT_WRITABLE(m) ) { 1017 KKASSERT(((mbcluster_t)m->m_ext.ext_arg)->mcl_magic == MCL_MAGIC); 1018 m->m_nextpkt = mcl_pool; 1019 mcl_pool = m; 1020 ++mcl_pool_count; 1021 m = NULL; 1022 } else { 1023 m->m_ext.ext_free(m->m_ext.ext_arg); 1024 m->m_flags = 0; 1025 m->m_ext.ext_arg = NULL; 1026 m->m_ext.ext_ref = NULL; 1027 m->m_ext.ext_free = NULL; 1028 } 1029 } 1030 if (m) { 1031 --mbtypes[m->m_type]; 1032 if (mbtypes[MT_FREE] < mbuf_free_max) { 1033 m->m_type = MT_FREE; 1034 mbtypes[MT_FREE]++; 1035 m->m_next = mmbfree; 1036 mmbfree = m; 1037 MMBWAKEUP(); 1038 } else { 1039 free(m, M_MBUF); 1040 --mbstat.m_mbufs; 1041 } 1042 } 1043 crit_exit(); 1044 return (n); 1045 } 1046 1047 void 1048 m_freem(struct mbuf *m) 1049 { 1050 crit_enter(); 1051 while (m) 1052 m = m_free(m); 1053 crit_exit(); 1054 } 1055 1056 /* 1057 * mbuf utility routines 1058 */ 1059 1060 /* 1061 * Lesser-used path for M_PREPEND: 1062 * allocate new mbuf to prepend to chain, 1063 * copy junk along. 1064 */ 1065 struct mbuf * 1066 m_prepend(struct mbuf *m, int len, int how) 1067 { 1068 struct mbuf *mn; 1069 1070 MGET(mn, how, m->m_type); 1071 if (mn == (struct mbuf *)NULL) { 1072 m_freem(m); 1073 return ((struct mbuf *)NULL); 1074 } 1075 if (m->m_flags & M_PKTHDR) 1076 M_MOVE_PKTHDR(mn, m); 1077 mn->m_next = m; 1078 m = mn; 1079 if (len < MHLEN) 1080 MH_ALIGN(m, len); 1081 m->m_len = len; 1082 return (m); 1083 } 1084 1085 /* 1086 * Make a copy of an mbuf chain starting "off0" bytes from the beginning, 1087 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf. 1088 * The wait parameter is a choice of MB_WAIT/MB_DONTWAIT from caller. 1089 * Note that the copy is read-only, because clusters are not copied, 1090 * only their reference counts are incremented. 1091 */ 1092 #define MCFail (mbstat.m_mcfail) 1093 1094 struct mbuf * 1095 m_copym(const struct mbuf *m, int off0, int len, int wait) 1096 { 1097 struct mbuf *n, **np; 1098 int off = off0; 1099 struct mbuf *top; 1100 int copyhdr = 0; 1101 1102 KASSERT(off >= 0, ("m_copym, negative off %d", off)); 1103 KASSERT(len >= 0, ("m_copym, negative len %d", len)); 1104 if (off == 0 && m->m_flags & M_PKTHDR) 1105 copyhdr = 1; 1106 while (off > 0) { 1107 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain")); 1108 if (off < m->m_len) 1109 break; 1110 off -= m->m_len; 1111 m = m->m_next; 1112 } 1113 np = ⊤ 1114 top = 0; 1115 while (len > 0) { 1116 if (m == 0) { 1117 KASSERT(len == M_COPYALL, 1118 ("m_copym, length > size of mbuf chain")); 1119 break; 1120 } 1121 MGET(n, wait, m->m_type); 1122 *np = n; 1123 if (n == 0) 1124 goto nospace; 1125 if (copyhdr) { 1126 if (!m_dup_pkthdr(n, m, wait)) 1127 goto nospace; 1128 if (len == M_COPYALL) 1129 n->m_pkthdr.len -= off0; 1130 else 1131 n->m_pkthdr.len = len; 1132 copyhdr = 0; 1133 } 1134 n->m_len = min(len, m->m_len - off); 1135 if (m->m_flags & M_EXT) { 1136 n->m_data = m->m_data + off; 1137 m_extref(m); 1138 n->m_ext = m->m_ext; 1139 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER); 1140 } else { 1141 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t), 1142 (unsigned)n->m_len); 1143 } 1144 if (len != M_COPYALL) 1145 len -= n->m_len; 1146 off = 0; 1147 m = m->m_next; 1148 np = &n->m_next; 1149 } 1150 if (top == 0) 1151 MCFail++; 1152 return (top); 1153 nospace: 1154 m_freem(top); 1155 MCFail++; 1156 return (0); 1157 } 1158 1159 /* 1160 * Copy an entire packet, including header (which must be present). 1161 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'. 1162 * Note that the copy is read-only, because clusters are not copied, 1163 * only their reference counts are incremented. 1164 * Preserve alignment of the first mbuf so if the creator has left 1165 * some room at the beginning (e.g. for inserting protocol headers) 1166 * the copies also have the room available. 1167 */ 1168 struct mbuf * 1169 m_copypacket(struct mbuf *m, int how) 1170 { 1171 struct mbuf *top, *n, *o; 1172 1173 MGET(n, how, m->m_type); 1174 top = n; 1175 if (!n) 1176 goto nospace; 1177 1178 if (!m_dup_pkthdr(n, m, how)) 1179 goto nospace; 1180 n->m_len = m->m_len; 1181 if (m->m_flags & M_EXT) { 1182 n->m_data = m->m_data; 1183 m_extref(m); 1184 n->m_ext = m->m_ext; 1185 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER); 1186 } else { 1187 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat ); 1188 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 1189 } 1190 1191 m = m->m_next; 1192 while (m) { 1193 MGET(o, how, m->m_type); 1194 if (!o) 1195 goto nospace; 1196 1197 n->m_next = o; 1198 n = n->m_next; 1199 1200 n->m_len = m->m_len; 1201 if (m->m_flags & M_EXT) { 1202 n->m_data = m->m_data; 1203 m_extref(m); 1204 n->m_ext = m->m_ext; 1205 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER); 1206 } else { 1207 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 1208 } 1209 1210 m = m->m_next; 1211 } 1212 return top; 1213 nospace: 1214 m_freem(top); 1215 MCFail++; 1216 return 0; 1217 } 1218 1219 /* 1220 * Copy data from an mbuf chain starting "off" bytes from the beginning, 1221 * continuing for "len" bytes, into the indicated buffer. 1222 */ 1223 void 1224 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp) 1225 { 1226 unsigned count; 1227 1228 KASSERT(off >= 0, ("m_copydata, negative off %d", off)); 1229 KASSERT(len >= 0, ("m_copydata, negative len %d", len)); 1230 while (off > 0) { 1231 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain")); 1232 if (off < m->m_len) 1233 break; 1234 off -= m->m_len; 1235 m = m->m_next; 1236 } 1237 while (len > 0) { 1238 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain")); 1239 count = min(m->m_len - off, len); 1240 bcopy(mtod(m, caddr_t) + off, cp, count); 1241 len -= count; 1242 cp += count; 1243 off = 0; 1244 m = m->m_next; 1245 } 1246 } 1247 1248 /* 1249 * Copy a packet header mbuf chain into a completely new chain, including 1250 * copying any mbuf clusters. Use this instead of m_copypacket() when 1251 * you need a writable copy of an mbuf chain. 1252 */ 1253 struct mbuf * 1254 m_dup(struct mbuf *m, int how) 1255 { 1256 struct mbuf **p, *top = NULL; 1257 int remain, moff, nsize; 1258 1259 /* Sanity check */ 1260 if (m == NULL) 1261 return (NULL); 1262 KASSERT((m->m_flags & M_PKTHDR) != 0, ("%s: !PKTHDR", __func__)); 1263 1264 /* While there's more data, get a new mbuf, tack it on, and fill it */ 1265 remain = m->m_pkthdr.len; 1266 moff = 0; 1267 p = ⊤ 1268 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */ 1269 struct mbuf *n; 1270 1271 /* Get the next new mbuf */ 1272 n = m_getl(remain, how, m->m_type, top == NULL ? M_PKTHDR : 0, 1273 &nsize); 1274 if (n == NULL) 1275 goto nospace; 1276 if (top == NULL) 1277 if (!m_dup_pkthdr(n, m, how)) 1278 goto nospace0; 1279 1280 /* Link it into the new chain */ 1281 *p = n; 1282 p = &n->m_next; 1283 1284 /* Copy data from original mbuf(s) into new mbuf */ 1285 n->m_len = 0; 1286 while (n->m_len < nsize && m != NULL) { 1287 int chunk = min(nsize - n->m_len, m->m_len - moff); 1288 1289 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk); 1290 moff += chunk; 1291 n->m_len += chunk; 1292 remain -= chunk; 1293 if (moff == m->m_len) { 1294 m = m->m_next; 1295 moff = 0; 1296 } 1297 } 1298 1299 /* Check correct total mbuf length */ 1300 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL), 1301 ("%s: bogus m_pkthdr.len", __func__)); 1302 } 1303 return (top); 1304 1305 nospace: 1306 m_freem(top); 1307 nospace0: 1308 mbstat.m_mcfail++; 1309 return (NULL); 1310 } 1311 1312 /* 1313 * Concatenate mbuf chain n to m. 1314 * Both chains must be of the same type (e.g. MT_DATA). 1315 * Any m_pkthdr is not updated. 1316 */ 1317 void 1318 m_cat(struct mbuf *m, struct mbuf *n) 1319 { 1320 m = m_last(m); 1321 while (n) { 1322 if (m->m_flags & M_EXT || 1323 m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) { 1324 /* just join the two chains */ 1325 m->m_next = n; 1326 return; 1327 } 1328 /* splat the data from one into the other */ 1329 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 1330 (u_int)n->m_len); 1331 m->m_len += n->m_len; 1332 n = m_free(n); 1333 } 1334 } 1335 1336 void 1337 m_adj(struct mbuf *mp, int req_len) 1338 { 1339 int len = req_len; 1340 struct mbuf *m; 1341 int count; 1342 1343 if ((m = mp) == NULL) 1344 return; 1345 if (len >= 0) { 1346 /* 1347 * Trim from head. 1348 */ 1349 while (m != NULL && len > 0) { 1350 if (m->m_len <= len) { 1351 len -= m->m_len; 1352 m->m_len = 0; 1353 m = m->m_next; 1354 } else { 1355 m->m_len -= len; 1356 m->m_data += len; 1357 len = 0; 1358 } 1359 } 1360 m = mp; 1361 if (mp->m_flags & M_PKTHDR) 1362 m->m_pkthdr.len -= (req_len - len); 1363 } else { 1364 /* 1365 * Trim from tail. Scan the mbuf chain, 1366 * calculating its length and finding the last mbuf. 1367 * If the adjustment only affects this mbuf, then just 1368 * adjust and return. Otherwise, rescan and truncate 1369 * after the remaining size. 1370 */ 1371 len = -len; 1372 count = 0; 1373 for (;;) { 1374 count += m->m_len; 1375 if (m->m_next == (struct mbuf *)0) 1376 break; 1377 m = m->m_next; 1378 } 1379 if (m->m_len >= len) { 1380 m->m_len -= len; 1381 if (mp->m_flags & M_PKTHDR) 1382 mp->m_pkthdr.len -= len; 1383 return; 1384 } 1385 count -= len; 1386 if (count < 0) 1387 count = 0; 1388 /* 1389 * Correct length for chain is "count". 1390 * Find the mbuf with last data, adjust its length, 1391 * and toss data from remaining mbufs on chain. 1392 */ 1393 m = mp; 1394 if (m->m_flags & M_PKTHDR) 1395 m->m_pkthdr.len = count; 1396 for (; m; m = m->m_next) { 1397 if (m->m_len >= count) { 1398 m->m_len = count; 1399 break; 1400 } 1401 count -= m->m_len; 1402 } 1403 while (m->m_next) 1404 (m = m->m_next) ->m_len = 0; 1405 } 1406 } 1407 1408 /* 1409 * Rearange an mbuf chain so that len bytes are contiguous 1410 * and in the data area of an mbuf (so that mtod will work for a structure 1411 * of size len). Returns the resulting mbuf chain on success, frees it and 1412 * returns null on failure. If there is room, it will add up to 1413 * max_protohdr-len extra bytes to the contiguous region in an attempt to 1414 * avoid being called next time. 1415 */ 1416 #define MPFail (mbstat.m_mpfail) 1417 1418 struct mbuf * 1419 m_pullup(struct mbuf *n, int len) 1420 { 1421 struct mbuf *m; 1422 int count; 1423 int space; 1424 1425 /* 1426 * If first mbuf has no cluster, and has room for len bytes 1427 * without shifting current data, pullup into it, 1428 * otherwise allocate a new mbuf to prepend to the chain. 1429 */ 1430 if ((n->m_flags & M_EXT) == 0 && 1431 n->m_data + len < &n->m_dat[MLEN] && n->m_next) { 1432 if (n->m_len >= len) 1433 return (n); 1434 m = n; 1435 n = n->m_next; 1436 len -= m->m_len; 1437 } else { 1438 if (len > MHLEN) 1439 goto bad; 1440 MGET(m, MB_DONTWAIT, n->m_type); 1441 if (m == 0) 1442 goto bad; 1443 m->m_len = 0; 1444 if (n->m_flags & M_PKTHDR) 1445 M_MOVE_PKTHDR(m, n); 1446 } 1447 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 1448 do { 1449 count = min(min(max(len, max_protohdr), space), n->m_len); 1450 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 1451 (unsigned)count); 1452 len -= count; 1453 m->m_len += count; 1454 n->m_len -= count; 1455 space -= count; 1456 if (n->m_len) 1457 n->m_data += count; 1458 else 1459 n = m_free(n); 1460 } while (len > 0 && n); 1461 if (len > 0) { 1462 (void) m_free(m); 1463 goto bad; 1464 } 1465 m->m_next = n; 1466 return (m); 1467 bad: 1468 m_freem(n); 1469 MPFail++; 1470 return (0); 1471 } 1472 1473 /* 1474 * Partition an mbuf chain in two pieces, returning the tail -- 1475 * all but the first len0 bytes. In case of failure, it returns NULL and 1476 * attempts to restore the chain to its original state. 1477 * 1478 * Note that the resulting mbufs might be read-only, because the new 1479 * mbuf can end up sharing an mbuf cluster with the original mbuf if 1480 * the "breaking point" happens to lie within a cluster mbuf. Use the 1481 * M_WRITABLE() macro to check for this case. 1482 */ 1483 struct mbuf * 1484 m_split(struct mbuf *m0, int len0, int wait) 1485 { 1486 struct mbuf *m, *n; 1487 unsigned len = len0, remain; 1488 1489 for (m = m0; m && len > m->m_len; m = m->m_next) 1490 len -= m->m_len; 1491 if (m == 0) 1492 return (0); 1493 remain = m->m_len - len; 1494 if (m0->m_flags & M_PKTHDR) { 1495 MGETHDR(n, wait, m0->m_type); 1496 if (n == 0) 1497 return (0); 1498 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; 1499 n->m_pkthdr.len = m0->m_pkthdr.len - len0; 1500 m0->m_pkthdr.len = len0; 1501 if (m->m_flags & M_EXT) 1502 goto extpacket; 1503 if (remain > MHLEN) { 1504 /* m can't be the lead packet */ 1505 MH_ALIGN(n, 0); 1506 n->m_next = m_split(m, len, wait); 1507 if (n->m_next == 0) { 1508 (void) m_free(n); 1509 return (0); 1510 } else { 1511 n->m_len = 0; 1512 return (n); 1513 } 1514 } else 1515 MH_ALIGN(n, remain); 1516 } else if (remain == 0) { 1517 n = m->m_next; 1518 m->m_next = 0; 1519 return (n); 1520 } else { 1521 MGET(n, wait, m->m_type); 1522 if (n == 0) 1523 return (0); 1524 M_ALIGN(n, remain); 1525 } 1526 extpacket: 1527 if (m->m_flags & M_EXT) { 1528 n->m_data = m->m_data + len; 1529 m_extref(m); 1530 n->m_ext = m->m_ext; 1531 n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER); 1532 } else { 1533 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain); 1534 } 1535 n->m_len = remain; 1536 m->m_len = len; 1537 n->m_next = m->m_next; 1538 m->m_next = 0; 1539 return (n); 1540 } 1541 1542 /* 1543 * Routine to copy from device local memory into mbufs. 1544 * Note: "offset" is ill-defined and always called as 0, so ignore it. 1545 */ 1546 struct mbuf * 1547 m_devget(char *buf, int len, int offset, struct ifnet *ifp, 1548 void (*copy)(volatile const void *from, volatile void *to, size_t length)) 1549 { 1550 struct mbuf *m, *mfirst = NULL, **mtail; 1551 int nsize, flags; 1552 1553 if (copy == NULL) 1554 copy = bcopy; 1555 mtail = &mfirst; 1556 flags = M_PKTHDR; 1557 1558 while (len > 0) { 1559 m = m_getl(len, MB_DONTWAIT, MT_DATA, flags, &nsize); 1560 if (m == NULL) { 1561 m_freem(mfirst); 1562 return (NULL); 1563 } 1564 m->m_len = min(len, nsize); 1565 1566 if (flags & M_PKTHDR) { 1567 if (len + max_linkhdr <= nsize) 1568 m->m_data += max_linkhdr; 1569 m->m_pkthdr.rcvif = ifp; 1570 m->m_pkthdr.len = len; 1571 flags = 0; 1572 } 1573 1574 copy(buf, m->m_data, (unsigned)m->m_len); 1575 buf += m->m_len; 1576 len -= m->m_len; 1577 *mtail = m; 1578 mtail = &m->m_next; 1579 } 1580 1581 return (mfirst); 1582 } 1583 1584 /* 1585 * Copy data from a buffer back into the indicated mbuf chain, 1586 * starting "off" bytes from the beginning, extending the mbuf 1587 * chain if necessary. 1588 */ 1589 void 1590 m_copyback(struct mbuf *m0, int off, int len, caddr_t cp) 1591 { 1592 int mlen; 1593 struct mbuf *m = m0, *n; 1594 int totlen = 0; 1595 1596 if (m0 == 0) 1597 return; 1598 while (off > (mlen = m->m_len)) { 1599 off -= mlen; 1600 totlen += mlen; 1601 if (m->m_next == 0) { 1602 n = m_getclr(MB_DONTWAIT, m->m_type); 1603 if (n == 0) 1604 goto out; 1605 n->m_len = min(MLEN, len + off); 1606 m->m_next = n; 1607 } 1608 m = m->m_next; 1609 } 1610 while (len > 0) { 1611 mlen = min (m->m_len - off, len); 1612 bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen); 1613 cp += mlen; 1614 len -= mlen; 1615 mlen += off; 1616 off = 0; 1617 totlen += mlen; 1618 if (len == 0) 1619 break; 1620 if (m->m_next == 0) { 1621 n = m_get(MB_DONTWAIT, m->m_type); 1622 if (n == 0) 1623 break; 1624 n->m_len = min(MLEN, len); 1625 m->m_next = n; 1626 } 1627 m = m->m_next; 1628 } 1629 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) 1630 m->m_pkthdr.len = totlen; 1631 } 1632 1633 void 1634 m_print(const struct mbuf *m) 1635 { 1636 int len; 1637 const struct mbuf *m2; 1638 1639 len = m->m_pkthdr.len; 1640 m2 = m; 1641 while (len) { 1642 printf("%p %*D\n", m2, m2->m_len, (u_char *)m2->m_data, "-"); 1643 len -= m2->m_len; 1644 m2 = m2->m_next; 1645 } 1646 return; 1647 } 1648 1649 /* 1650 * "Move" mbuf pkthdr from "from" to "to". 1651 * "from" must have M_PKTHDR set, and "to" must be empty. 1652 */ 1653 void 1654 m_move_pkthdr(struct mbuf *to, struct mbuf *from) 1655 { 1656 KASSERT((to->m_flags & M_EXT) == 0, ("m_move_pkthdr: to has cluster")); 1657 1658 to->m_flags = from->m_flags & M_COPYFLAGS; 1659 to->m_data = to->m_pktdat; 1660 to->m_pkthdr = from->m_pkthdr; /* especially tags */ 1661 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */ 1662 from->m_flags &= ~M_PKTHDR; 1663 } 1664 1665 /* 1666 * Duplicate "from"'s mbuf pkthdr in "to". 1667 * "from" must have M_PKTHDR set, and "to" must be empty. 1668 * In particular, this does a deep copy of the packet tags. 1669 */ 1670 int 1671 m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how) 1672 { 1673 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT); 1674 if ((to->m_flags & M_EXT) == 0) 1675 to->m_data = to->m_pktdat; 1676 to->m_pkthdr = from->m_pkthdr; 1677 SLIST_INIT(&to->m_pkthdr.tags); 1678 return (m_tag_copy_chain(to, from, how)); 1679 } 1680 1681 /* 1682 * Defragment a mbuf chain, returning the shortest possible 1683 * chain of mbufs and clusters. If allocation fails and 1684 * this cannot be completed, NULL will be returned, but 1685 * the passed in chain will be unchanged. Upon success, 1686 * the original chain will be freed, and the new chain 1687 * will be returned. 1688 * 1689 * If a non-packet header is passed in, the original 1690 * mbuf (chain?) will be returned unharmed. 1691 * 1692 * m_defrag_nofree doesn't free the passed in mbuf. 1693 */ 1694 struct mbuf * 1695 m_defrag(struct mbuf *m0, int how) 1696 { 1697 struct mbuf *m_new; 1698 1699 if ((m_new = m_defrag_nofree(m0, how)) == NULL) 1700 return (NULL); 1701 if (m_new != m0) 1702 m_freem(m0); 1703 return (m_new); 1704 } 1705 1706 struct mbuf * 1707 m_defrag_nofree(struct mbuf *m0, int how) 1708 { 1709 struct mbuf *m_new = NULL, *m_final = NULL; 1710 int progress = 0, length, nsize; 1711 1712 if (!(m0->m_flags & M_PKTHDR)) 1713 return (m0); 1714 1715 #ifdef MBUF_STRESS_TEST 1716 if (m_defragrandomfailures) { 1717 int temp = arc4random() & 0xff; 1718 if (temp == 0xba) 1719 goto nospace; 1720 } 1721 #endif 1722 1723 m_final = m_getl(m0->m_pkthdr.len, how, MT_DATA, M_PKTHDR, &nsize); 1724 if (m_final == NULL) 1725 goto nospace; 1726 m_final->m_len = 0; /* in case m0->m_pkthdr.len is zero */ 1727 1728 if (m_dup_pkthdr(m_final, m0, how) == NULL) 1729 goto nospace; 1730 1731 m_new = m_final; 1732 1733 while (progress < m0->m_pkthdr.len) { 1734 length = m0->m_pkthdr.len - progress; 1735 if (length > MCLBYTES) 1736 length = MCLBYTES; 1737 1738 if (m_new == NULL) { 1739 m_new = m_getl(length, how, MT_DATA, 0, &nsize); 1740 if (m_new == NULL) 1741 goto nospace; 1742 } 1743 1744 m_copydata(m0, progress, length, mtod(m_new, caddr_t)); 1745 progress += length; 1746 m_new->m_len = length; 1747 if (m_new != m_final) 1748 m_cat(m_final, m_new); 1749 m_new = NULL; 1750 } 1751 if (m0->m_next == NULL) 1752 m_defraguseless++; 1753 m_defragpackets++; 1754 m_defragbytes += m_final->m_pkthdr.len; 1755 return (m_final); 1756 nospace: 1757 m_defragfailure++; 1758 if (m_new) 1759 m_free(m_new); 1760 m_freem(m_final); 1761 return (NULL); 1762 } 1763 1764 /* 1765 * Move data from uio into mbufs. 1766 */ 1767 struct mbuf * 1768 m_uiomove(struct uio *uio) 1769 { 1770 struct mbuf *m; /* current working mbuf */ 1771 struct mbuf *head = NULL; /* result mbuf chain */ 1772 struct mbuf **mp = &head; 1773 int resid = uio->uio_resid, nsize, flags = M_PKTHDR, error; 1774 1775 do { 1776 m = m_getl(resid, MB_WAIT, MT_DATA, flags, &nsize); 1777 if (flags) { 1778 m->m_pkthdr.len = 0; 1779 /* Leave room for protocol headers. */ 1780 if (resid < MHLEN) 1781 MH_ALIGN(m, resid); 1782 flags = 0; 1783 } 1784 m->m_len = min(nsize, resid); 1785 error = uiomove(mtod(m, caddr_t), m->m_len, uio); 1786 if (error) { 1787 m_free(m); 1788 goto failed; 1789 } 1790 *mp = m; 1791 mp = &m->m_next; 1792 head->m_pkthdr.len += m->m_len; 1793 resid -= m->m_len; 1794 } while (resid > 0); 1795 1796 return (head); 1797 1798 failed: 1799 m_freem(head); 1800 return (NULL); 1801 } 1802 1803 struct mbuf * 1804 m_last(struct mbuf *m) 1805 { 1806 while (m->m_next) 1807 m = m->m_next; 1808 return (m); 1809 } 1810 1811 /* 1812 * Return the number of bytes in an mbuf chain. 1813 * If lastm is not NULL, also return the last mbuf. 1814 */ 1815 u_int 1816 m_lengthm(struct mbuf *m, struct mbuf **lastm) 1817 { 1818 u_int len = 0; 1819 struct mbuf *prev = m; 1820 1821 while (m) { 1822 len += m->m_len; 1823 prev = m; 1824 m = m->m_next; 1825 } 1826 if (lastm != NULL) 1827 *lastm = prev; 1828 return (len); 1829 } 1830 1831 /* 1832 * Like m_lengthm(), except also keep track of mbuf usage. 1833 */ 1834 u_int 1835 m_countm(struct mbuf *m, struct mbuf **lastm, u_int *pmbcnt) 1836 { 1837 u_int len = 0, mbcnt = 0; 1838 struct mbuf *prev = m; 1839 1840 while (m) { 1841 len += m->m_len; 1842 mbcnt += MSIZE; 1843 if (m->m_flags & M_EXT) 1844 mbcnt += m->m_ext.ext_size; 1845 prev = m; 1846 m = m->m_next; 1847 } 1848 if (lastm != NULL) 1849 *lastm = prev; 1850 *pmbcnt = mbcnt; 1851 return (len); 1852 } 1853