uipc_mbuf.c revision 54002
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: head/sys/kern/uipc_mbuf.c 54002 1999-12-01 22:31:32Z archie $ 35 */ 36 37#include "opt_param.h" 38#include <sys/param.h> 39#include <sys/systm.h> 40#include <sys/malloc.h> 41#include <sys/mbuf.h> 42#include <sys/kernel.h> 43#include <sys/sysctl.h> 44#include <sys/domain.h> 45#include <sys/protosw.h> 46 47#include <vm/vm.h> 48#include <vm/vm_kern.h> 49#include <vm/vm_extern.h> 50 51static void mbinit __P((void *)); 52SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL) 53 54struct mbuf *mbutl; 55char *mclrefcnt; 56struct mbstat mbstat; 57struct mbuf *mmbfree; 58union mcluster *mclfree; 59int max_linkhdr; 60int max_protohdr; 61int max_hdr; 62int max_datalen; 63int nmbclusters; 64int nmbufs; 65 66SYSCTL_DECL(_kern_ipc); 67SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW, 68 &max_linkhdr, 0, ""); 69SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW, 70 &max_protohdr, 0, ""); 71SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0, ""); 72SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW, 73 &max_datalen, 0, ""); 74SYSCTL_STRUCT(_kern_ipc, KIPC_MBSTAT, mbstat, CTLFLAG_RW, &mbstat, mbstat, ""); 75SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters, CTLFLAG_RD, 76 &nmbclusters, 0, "Maximum number of mbuf clusters avaliable"); 77#ifndef NMBCLUSTERS 78#define NMBCLUSTERS (512 + MAXUSERS * 16) 79#endif 80TUNABLE_INT_DECL("kern.ipc.nmbclusters", NMBCLUSTERS, nmbclusters); 81TUNABLE_INT_DECL("kern.ipc.nmbufs", NMBCLUSTERS * 4, nmbufs); /* XXX fixup? */ 82 83static void m_reclaim __P((void)); 84 85/* "number of clusters of pages" */ 86#define NCL_INIT 1 87 88#define NMB_INIT 16 89 90/* ARGSUSED*/ 91static void 92mbinit(dummy) 93 void *dummy; 94{ 95 int s; 96 97 mmbfree = NULL; mclfree = NULL; 98 mbstat.m_msize = MSIZE; 99 mbstat.m_mclbytes = MCLBYTES; 100 mbstat.m_minclsize = MINCLSIZE; 101 mbstat.m_mlen = MLEN; 102 mbstat.m_mhlen = MHLEN; 103 104 s = splimp(); 105 if (m_mballoc(NMB_INIT, M_DONTWAIT) == 0) 106 goto bad; 107#if MCLBYTES <= PAGE_SIZE 108 if (m_clalloc(NCL_INIT, M_DONTWAIT) == 0) 109 goto bad; 110#else 111 /* It's OK to call contigmalloc in this context. */ 112 if (m_clalloc(16, M_WAIT) == 0) 113 goto bad; 114#endif 115 splx(s); 116 return; 117bad: 118 panic("mbinit"); 119} 120 121/* 122 * Allocate at least nmb mbufs and place on mbuf free list. 123 * Must be called at splimp. 124 */ 125/* ARGSUSED */ 126int 127m_mballoc(nmb, how) 128 register int nmb; 129 int how; 130{ 131 register caddr_t p; 132 register int i; 133 int nbytes; 134 135 /* Once we run out of map space, it will be impossible to get 136 * any more (nothing is ever freed back to the map) (XXX which 137 * is dumb). (however you are not dead as m_reclaim might 138 * still be able to free a substantial amount of space). 139 */ 140 if (mb_map_full) 141 return (0); 142 143 nbytes = round_page(nmb * MSIZE); 144 p = (caddr_t)kmem_malloc(mb_map, nbytes, M_NOWAIT); 145 if (p == 0 && how == M_WAIT) { 146 mbstat.m_wait++; 147 p = (caddr_t)kmem_malloc(mb_map, nbytes, M_WAITOK); 148 } 149 150 /* 151 * Either the map is now full, or `how' is M_NOWAIT and there 152 * are no pages left. 153 */ 154 if (p == NULL) 155 return (0); 156 157 nmb = nbytes / MSIZE; 158 for (i = 0; i < nmb; i++) { 159 ((struct mbuf *)p)->m_next = mmbfree; 160 mmbfree = (struct mbuf *)p; 161 p += MSIZE; 162 } 163 mbstat.m_mbufs += nmb; 164 return (1); 165} 166 167#if MCLBYTES > PAGE_SIZE 168static int i_want_my_mcl; 169 170static void 171kproc_mclalloc(void) 172{ 173 int status; 174 175 while (1) { 176 tsleep(&i_want_my_mcl, PVM, "mclalloc", 0); 177 178 for (; i_want_my_mcl; i_want_my_mcl--) { 179 if (m_clalloc(1, M_WAIT) == 0) 180 printf("m_clalloc failed even in process context!\n"); 181 } 182 } 183} 184 185static struct proc *mclallocproc; 186static struct kproc_desc mclalloc_kp = { 187 "mclalloc", 188 kproc_mclalloc, 189 &mclallocproc 190}; 191SYSINIT(mclallocproc, SI_SUB_KTHREAD_UPDATE, SI_ORDER_ANY, kproc_start, 192 &mclalloc_kp); 193#endif 194 195/* 196 * Allocate some number of mbuf clusters 197 * and place on cluster free list. 198 * Must be called at splimp. 199 */ 200/* ARGSUSED */ 201int 202m_clalloc(ncl, how) 203 register int ncl; 204 int how; 205{ 206 register caddr_t p; 207 register int i; 208 int npg; 209 210 /* 211 * Once we run out of map space, it will be impossible 212 * to get any more (nothing is ever freed back to the 213 * map). 214 */ 215 if (mb_map_full) { 216 mbstat.m_drops++; 217 return (0); 218 } 219 220#if MCLBYTES > PAGE_SIZE 221 if (how != M_WAIT) { 222 i_want_my_mcl += ncl; 223 wakeup(&i_want_my_mcl); 224 mbstat.m_wait++; 225 p = 0; 226 } else { 227 p = contigmalloc1(MCLBYTES * ncl, M_DEVBUF, M_WAITOK, 0ul, 228 ~0ul, PAGE_SIZE, 0, mb_map); 229 } 230#else 231 npg = ncl; 232 p = (caddr_t)kmem_malloc(mb_map, ctob(npg), 233 how != M_WAIT ? M_NOWAIT : M_WAITOK); 234 ncl = ncl * PAGE_SIZE / MCLBYTES; 235#endif 236 /* 237 * Either the map is now full, or `how' is M_NOWAIT and there 238 * are no pages left. 239 */ 240 if (p == NULL) { 241 mbstat.m_drops++; 242 return (0); 243 } 244 245 for (i = 0; i < ncl; i++) { 246 ((union mcluster *)p)->mcl_next = mclfree; 247 mclfree = (union mcluster *)p; 248 p += MCLBYTES; 249 mbstat.m_clfree++; 250 } 251 mbstat.m_clusters += ncl; 252 return (1); 253} 254 255/* 256 * When MGET fails, ask protocols to free space when short of memory, 257 * then re-attempt to allocate an mbuf. 258 */ 259struct mbuf * 260m_retry(i, t) 261 int i, t; 262{ 263 register struct mbuf *m; 264 265 /* 266 * Must only do the reclaim if not in an interrupt context. 267 */ 268 if (i == M_WAIT) 269 m_reclaim(); 270#define m_retry(i, t) (struct mbuf *)0 271 MGET(m, i, t); 272#undef m_retry 273 if (m != NULL) { 274 mbstat.m_wait++; 275 } else { 276 if (i == M_DONTWAIT) 277 mbstat.m_drops++; 278 else 279 panic("Out of mbuf clusters"); 280 } 281 return (m); 282} 283 284/* 285 * As above; retry an MGETHDR. 286 */ 287struct mbuf * 288m_retryhdr(i, t) 289 int i, t; 290{ 291 register struct mbuf *m; 292 293 /* 294 * Must only do the reclaim if not in an interrupt context. 295 */ 296 if (i == M_WAIT) 297 m_reclaim(); 298#define m_retryhdr(i, t) (struct mbuf *)0 299 MGETHDR(m, i, t); 300#undef m_retryhdr 301 if (m != NULL) { 302 mbstat.m_wait++; 303 } else { 304 if (i == M_DONTWAIT) 305 mbstat.m_drops++; 306 else 307 panic("Out of mbuf clusters"); 308 } 309 return (m); 310} 311 312static void 313m_reclaim() 314{ 315 register struct domain *dp; 316 register struct protosw *pr; 317 int s = splimp(); 318 319 for (dp = domains; dp; dp = dp->dom_next) 320 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) 321 if (pr->pr_drain) 322 (*pr->pr_drain)(); 323 splx(s); 324 mbstat.m_drain++; 325} 326 327/* 328 * Space allocation routines. 329 * These are also available as macros 330 * for critical paths. 331 */ 332struct mbuf * 333m_get(how, type) 334 int how, type; 335{ 336 register struct mbuf *m; 337 338 MGET(m, how, type); 339 return (m); 340} 341 342struct mbuf * 343m_gethdr(how, type) 344 int how, type; 345{ 346 register struct mbuf *m; 347 348 MGETHDR(m, how, type); 349 return (m); 350} 351 352struct mbuf * 353m_getclr(how, type) 354 int how, type; 355{ 356 register struct mbuf *m; 357 358 MGET(m, how, type); 359 if (m == 0) 360 return (0); 361 bzero(mtod(m, caddr_t), MLEN); 362 return (m); 363} 364 365struct mbuf * 366m_free(m) 367 struct mbuf *m; 368{ 369 register struct mbuf *n; 370 371 MFREE(m, n); 372 return (n); 373} 374 375void 376m_freem(m) 377 register struct mbuf *m; 378{ 379 register struct mbuf *n; 380 381 if (m == NULL) 382 return; 383 do { 384 MFREE(m, n); 385 m = n; 386 } while (m); 387} 388 389/* 390 * Mbuffer utility routines. 391 */ 392 393/* 394 * Lesser-used path for M_PREPEND: 395 * allocate new mbuf to prepend to chain, 396 * copy junk along. 397 */ 398struct mbuf * 399m_prepend(m, len, how) 400 register struct mbuf *m; 401 int len, how; 402{ 403 struct mbuf *mn; 404 405 MGET(mn, how, m->m_type); 406 if (mn == (struct mbuf *)NULL) { 407 m_freem(m); 408 return ((struct mbuf *)NULL); 409 } 410 if (m->m_flags & M_PKTHDR) { 411 M_COPY_PKTHDR(mn, m); 412 m->m_flags &= ~M_PKTHDR; 413 } 414 mn->m_next = m; 415 m = mn; 416 if (len < MHLEN) 417 MH_ALIGN(m, len); 418 m->m_len = len; 419 return (m); 420} 421 422/* 423 * Make a copy of an mbuf chain starting "off0" bytes from the beginning, 424 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf. 425 * The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller. 426 * Note that the copy is read-only, because clusters are not copied, 427 * only their reference counts are incremented. 428 */ 429#define MCFail (mbstat.m_mcfail) 430 431struct mbuf * 432m_copym(m, off0, len, wait) 433 register struct mbuf *m; 434 int off0, wait; 435 register int len; 436{ 437 register struct mbuf *n, **np; 438 register int off = off0; 439 struct mbuf *top; 440 int copyhdr = 0; 441 442 KASSERT(off >= 0, ("m_copym, negative off %d", off)); 443 KASSERT(len >= 0, ("m_copym, negative len %d", len)); 444 if (off == 0 && m->m_flags & M_PKTHDR) 445 copyhdr = 1; 446 while (off > 0) { 447 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain")); 448 if (off < m->m_len) 449 break; 450 off -= m->m_len; 451 m = m->m_next; 452 } 453 np = ⊤ 454 top = 0; 455 while (len > 0) { 456 if (m == 0) { 457 KASSERT(len == M_COPYALL, 458 ("m_copym, length > size of mbuf chain")); 459 break; 460 } 461 MGET(n, wait, m->m_type); 462 *np = n; 463 if (n == 0) 464 goto nospace; 465 if (copyhdr) { 466 M_COPY_PKTHDR(n, m); 467 if (len == M_COPYALL) 468 n->m_pkthdr.len -= off0; 469 else 470 n->m_pkthdr.len = len; 471 copyhdr = 0; 472 } 473 n->m_len = min(len, m->m_len - off); 474 if (m->m_flags & M_EXT) { 475 n->m_data = m->m_data + off; 476 if(!m->m_ext.ext_ref) 477 mclrefcnt[mtocl(m->m_ext.ext_buf)]++; 478 else 479 (*(m->m_ext.ext_ref))(m->m_ext.ext_buf, 480 m->m_ext.ext_size); 481 n->m_ext = m->m_ext; 482 n->m_flags |= M_EXT; 483 } else 484 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t), 485 (unsigned)n->m_len); 486 if (len != M_COPYALL) 487 len -= n->m_len; 488 off = 0; 489 m = m->m_next; 490 np = &n->m_next; 491 } 492 if (top == 0) 493 MCFail++; 494 return (top); 495nospace: 496 m_freem(top); 497 MCFail++; 498 return (0); 499} 500 501/* 502 * Copy an entire packet, including header (which must be present). 503 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'. 504 * Note that the copy is read-only, because clusters are not copied, 505 * only their reference counts are incremented. 506 */ 507struct mbuf * 508m_copypacket(m, how) 509 struct mbuf *m; 510 int how; 511{ 512 struct mbuf *top, *n, *o; 513 514 MGET(n, how, m->m_type); 515 top = n; 516 if (!n) 517 goto nospace; 518 519 M_COPY_PKTHDR(n, m); 520 n->m_len = m->m_len; 521 if (m->m_flags & M_EXT) { 522 n->m_data = m->m_data; 523 if(!m->m_ext.ext_ref) 524 mclrefcnt[mtocl(m->m_ext.ext_buf)]++; 525 else 526 (*(m->m_ext.ext_ref))(m->m_ext.ext_buf, 527 m->m_ext.ext_size); 528 n->m_ext = m->m_ext; 529 n->m_flags |= M_EXT; 530 } else { 531 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 532 } 533 534 m = m->m_next; 535 while (m) { 536 MGET(o, how, m->m_type); 537 if (!o) 538 goto nospace; 539 540 n->m_next = o; 541 n = n->m_next; 542 543 n->m_len = m->m_len; 544 if (m->m_flags & M_EXT) { 545 n->m_data = m->m_data; 546 if(!m->m_ext.ext_ref) 547 mclrefcnt[mtocl(m->m_ext.ext_buf)]++; 548 else 549 (*(m->m_ext.ext_ref))(m->m_ext.ext_buf, 550 m->m_ext.ext_size); 551 n->m_ext = m->m_ext; 552 n->m_flags |= M_EXT; 553 } else { 554 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 555 } 556 557 m = m->m_next; 558 } 559 return top; 560nospace: 561 m_freem(top); 562 MCFail++; 563 return 0; 564} 565 566/* 567 * Copy data from an mbuf chain starting "off" bytes from the beginning, 568 * continuing for "len" bytes, into the indicated buffer. 569 */ 570void 571m_copydata(m, off, len, cp) 572 register struct mbuf *m; 573 register int off; 574 register int len; 575 caddr_t cp; 576{ 577 register unsigned count; 578 579 KASSERT(off >= 0, ("m_copydata, negative off %d", off)); 580 KASSERT(len >= 0, ("m_copydata, negative len %d", len)); 581 while (off > 0) { 582 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain")); 583 if (off < m->m_len) 584 break; 585 off -= m->m_len; 586 m = m->m_next; 587 } 588 while (len > 0) { 589 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain")); 590 count = min(m->m_len - off, len); 591 bcopy(mtod(m, caddr_t) + off, cp, count); 592 len -= count; 593 cp += count; 594 off = 0; 595 m = m->m_next; 596 } 597} 598 599/* 600 * Copy a packet header mbuf chain into a completely new chain, including 601 * copying any mbuf clusters. Use this instead of m_copypacket() when 602 * you need a writable copy of an mbuf chain. 603 */ 604struct mbuf * 605m_dup(m, how) 606 struct mbuf *m; 607 int how; 608{ 609 struct mbuf **p, *top = NULL; 610 int remain, moff, nsize; 611 612 /* Sanity check */ 613 if (m == NULL) 614 return (0); 615 KASSERT((m->m_flags & M_PKTHDR) != 0, ("%s: !PKTHDR", __FUNCTION__)); 616 617 /* While there's more data, get a new mbuf, tack it on, and fill it */ 618 remain = m->m_pkthdr.len; 619 moff = 0; 620 p = ⊤ 621 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */ 622 struct mbuf *n; 623 624 /* Get the next new mbuf */ 625 MGET(n, how, m->m_type); 626 if (n == NULL) 627 goto nospace; 628 if (top == NULL) { /* first one, must be PKTHDR */ 629 M_COPY_PKTHDR(n, m); 630 nsize = MHLEN; 631 } else /* not the first one */ 632 nsize = MLEN; 633 if (remain >= MINCLSIZE) { 634 MCLGET(n, how); 635 if ((n->m_flags & M_EXT) == 0) { 636 (void)m_free(n); 637 goto nospace; 638 } 639 nsize = MCLBYTES; 640 } 641 n->m_len = 0; 642 643 /* Link it into the new chain */ 644 *p = n; 645 p = &n->m_next; 646 647 /* Copy data from original mbuf(s) into new mbuf */ 648 while (n->m_len < nsize && m != NULL) { 649 int chunk = min(nsize - n->m_len, m->m_len - moff); 650 651 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk); 652 moff += chunk; 653 n->m_len += chunk; 654 remain -= chunk; 655 if (moff == m->m_len) { 656 m = m->m_next; 657 moff = 0; 658 } 659 } 660 661 /* Check correct total mbuf length */ 662 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL), 663 ("%s: bogus m_pkthdr.len", __FUNCTION__)); 664 } 665 return (top); 666 667nospace: 668 m_freem(top); 669 MCFail++; 670 return (0); 671} 672 673/* 674 * Concatenate mbuf chain n to m. 675 * Both chains must be of the same type (e.g. MT_DATA). 676 * Any m_pkthdr is not updated. 677 */ 678void 679m_cat(m, n) 680 register struct mbuf *m, *n; 681{ 682 while (m->m_next) 683 m = m->m_next; 684 while (n) { 685 if (m->m_flags & M_EXT || 686 m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) { 687 /* just join the two chains */ 688 m->m_next = n; 689 return; 690 } 691 /* splat the data from one into the other */ 692 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 693 (u_int)n->m_len); 694 m->m_len += n->m_len; 695 n = m_free(n); 696 } 697} 698 699void 700m_adj(mp, req_len) 701 struct mbuf *mp; 702 int req_len; 703{ 704 register int len = req_len; 705 register struct mbuf *m; 706 register int count; 707 708 if ((m = mp) == NULL) 709 return; 710 if (len >= 0) { 711 /* 712 * Trim from head. 713 */ 714 while (m != NULL && len > 0) { 715 if (m->m_len <= len) { 716 len -= m->m_len; 717 m->m_len = 0; 718 m = m->m_next; 719 } else { 720 m->m_len -= len; 721 m->m_data += len; 722 len = 0; 723 } 724 } 725 m = mp; 726 if (mp->m_flags & M_PKTHDR) 727 m->m_pkthdr.len -= (req_len - len); 728 } else { 729 /* 730 * Trim from tail. Scan the mbuf chain, 731 * calculating its length and finding the last mbuf. 732 * If the adjustment only affects this mbuf, then just 733 * adjust and return. Otherwise, rescan and truncate 734 * after the remaining size. 735 */ 736 len = -len; 737 count = 0; 738 for (;;) { 739 count += m->m_len; 740 if (m->m_next == (struct mbuf *)0) 741 break; 742 m = m->m_next; 743 } 744 if (m->m_len >= len) { 745 m->m_len -= len; 746 if (mp->m_flags & M_PKTHDR) 747 mp->m_pkthdr.len -= len; 748 return; 749 } 750 count -= len; 751 if (count < 0) 752 count = 0; 753 /* 754 * Correct length for chain is "count". 755 * Find the mbuf with last data, adjust its length, 756 * and toss data from remaining mbufs on chain. 757 */ 758 m = mp; 759 if (m->m_flags & M_PKTHDR) 760 m->m_pkthdr.len = count; 761 for (; m; m = m->m_next) { 762 if (m->m_len >= count) { 763 m->m_len = count; 764 break; 765 } 766 count -= m->m_len; 767 } 768 while (m->m_next) 769 (m = m->m_next) ->m_len = 0; 770 } 771} 772 773/* 774 * Rearange an mbuf chain so that len bytes are contiguous 775 * and in the data area of an mbuf (so that mtod and dtom 776 * will work for a structure of size len). Returns the resulting 777 * mbuf chain on success, frees it and returns null on failure. 778 * If there is room, it will add up to max_protohdr-len extra bytes to the 779 * contiguous region in an attempt to avoid being called next time. 780 */ 781#define MPFail (mbstat.m_mpfail) 782 783struct mbuf * 784m_pullup(n, len) 785 register struct mbuf *n; 786 int len; 787{ 788 register struct mbuf *m; 789 register int count; 790 int space; 791 792 /* 793 * If first mbuf has no cluster, and has room for len bytes 794 * without shifting current data, pullup into it, 795 * otherwise allocate a new mbuf to prepend to the chain. 796 */ 797 if ((n->m_flags & M_EXT) == 0 && 798 n->m_data + len < &n->m_dat[MLEN] && n->m_next) { 799 if (n->m_len >= len) 800 return (n); 801 m = n; 802 n = n->m_next; 803 len -= m->m_len; 804 } else { 805 if (len > MHLEN) 806 goto bad; 807 MGET(m, M_DONTWAIT, n->m_type); 808 if (m == 0) 809 goto bad; 810 m->m_len = 0; 811 if (n->m_flags & M_PKTHDR) { 812 M_COPY_PKTHDR(m, n); 813 n->m_flags &= ~M_PKTHDR; 814 } 815 } 816 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 817 do { 818 count = min(min(max(len, max_protohdr), space), n->m_len); 819 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 820 (unsigned)count); 821 len -= count; 822 m->m_len += count; 823 n->m_len -= count; 824 space -= count; 825 if (n->m_len) 826 n->m_data += count; 827 else 828 n = m_free(n); 829 } while (len > 0 && n); 830 if (len > 0) { 831 (void) m_free(m); 832 goto bad; 833 } 834 m->m_next = n; 835 return (m); 836bad: 837 m_freem(n); 838 MPFail++; 839 return (0); 840} 841 842/* 843 * Partition an mbuf chain in two pieces, returning the tail -- 844 * all but the first len0 bytes. In case of failure, it returns NULL and 845 * attempts to restore the chain to its original state. 846 */ 847struct mbuf * 848m_split(m0, len0, wait) 849 register struct mbuf *m0; 850 int len0, wait; 851{ 852 register struct mbuf *m, *n; 853 unsigned len = len0, remain; 854 855 for (m = m0; m && len > m->m_len; m = m->m_next) 856 len -= m->m_len; 857 if (m == 0) 858 return (0); 859 remain = m->m_len - len; 860 if (m0->m_flags & M_PKTHDR) { 861 MGETHDR(n, wait, m0->m_type); 862 if (n == 0) 863 return (0); 864 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; 865 n->m_pkthdr.len = m0->m_pkthdr.len - len0; 866 m0->m_pkthdr.len = len0; 867 if (m->m_flags & M_EXT) 868 goto extpacket; 869 if (remain > MHLEN) { 870 /* m can't be the lead packet */ 871 MH_ALIGN(n, 0); 872 n->m_next = m_split(m, len, wait); 873 if (n->m_next == 0) { 874 (void) m_free(n); 875 return (0); 876 } else 877 return (n); 878 } else 879 MH_ALIGN(n, remain); 880 } else if (remain == 0) { 881 n = m->m_next; 882 m->m_next = 0; 883 return (n); 884 } else { 885 MGET(n, wait, m->m_type); 886 if (n == 0) 887 return (0); 888 M_ALIGN(n, remain); 889 } 890extpacket: 891 if (m->m_flags & M_EXT) { 892 n->m_flags |= M_EXT; 893 n->m_ext = m->m_ext; 894 if(!m->m_ext.ext_ref) 895 mclrefcnt[mtocl(m->m_ext.ext_buf)]++; 896 else 897 (*(m->m_ext.ext_ref))(m->m_ext.ext_buf, 898 m->m_ext.ext_size); 899 m->m_ext.ext_size = 0; /* For Accounting XXXXXX danger */ 900 n->m_data = m->m_data + len; 901 } else { 902 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain); 903 } 904 n->m_len = remain; 905 m->m_len = len; 906 n->m_next = m->m_next; 907 m->m_next = 0; 908 return (n); 909} 910/* 911 * Routine to copy from device local memory into mbufs. 912 */ 913struct mbuf * 914m_devget(buf, totlen, off0, ifp, copy) 915 char *buf; 916 int totlen, off0; 917 struct ifnet *ifp; 918 void (*copy) __P((char *from, caddr_t to, u_int len)); 919{ 920 register struct mbuf *m; 921 struct mbuf *top = 0, **mp = ⊤ 922 register int off = off0, len; 923 register char *cp; 924 char *epkt; 925 926 cp = buf; 927 epkt = cp + totlen; 928 if (off) { 929 cp += off + 2 * sizeof(u_short); 930 totlen -= 2 * sizeof(u_short); 931 } 932 MGETHDR(m, M_DONTWAIT, MT_DATA); 933 if (m == 0) 934 return (0); 935 m->m_pkthdr.rcvif = ifp; 936 m->m_pkthdr.len = totlen; 937 m->m_len = MHLEN; 938 939 while (totlen > 0) { 940 if (top) { 941 MGET(m, M_DONTWAIT, MT_DATA); 942 if (m == 0) { 943 m_freem(top); 944 return (0); 945 } 946 m->m_len = MLEN; 947 } 948 len = min(totlen, epkt - cp); 949 if (len >= MINCLSIZE) { 950 MCLGET(m, M_DONTWAIT); 951 if (m->m_flags & M_EXT) 952 m->m_len = len = min(len, MCLBYTES); 953 else 954 len = m->m_len; 955 } else { 956 /* 957 * Place initial small packet/header at end of mbuf. 958 */ 959 if (len < m->m_len) { 960 if (top == 0 && len + max_linkhdr <= m->m_len) 961 m->m_data += max_linkhdr; 962 m->m_len = len; 963 } else 964 len = m->m_len; 965 } 966 if (copy) 967 copy(cp, mtod(m, caddr_t), (unsigned)len); 968 else 969 bcopy(cp, mtod(m, caddr_t), (unsigned)len); 970 cp += len; 971 *mp = m; 972 mp = &m->m_next; 973 totlen -= len; 974 if (cp == epkt) 975 cp = buf; 976 } 977 return (top); 978} 979 980/* 981 * Copy data from a buffer back into the indicated mbuf chain, 982 * starting "off" bytes from the beginning, extending the mbuf 983 * chain if necessary. 984 */ 985void 986m_copyback(m0, off, len, cp) 987 struct mbuf *m0; 988 register int off; 989 register int len; 990 caddr_t cp; 991{ 992 register int mlen; 993 register struct mbuf *m = m0, *n; 994 int totlen = 0; 995 996 if (m0 == 0) 997 return; 998 while (off > (mlen = m->m_len)) { 999 off -= mlen; 1000 totlen += mlen; 1001 if (m->m_next == 0) { 1002 n = m_getclr(M_DONTWAIT, m->m_type); 1003 if (n == 0) 1004 goto out; 1005 n->m_len = min(MLEN, len + off); 1006 m->m_next = n; 1007 } 1008 m = m->m_next; 1009 } 1010 while (len > 0) { 1011 mlen = min (m->m_len - off, len); 1012 bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen); 1013 cp += mlen; 1014 len -= mlen; 1015 mlen += off; 1016 off = 0; 1017 totlen += mlen; 1018 if (len == 0) 1019 break; 1020 if (m->m_next == 0) { 1021 n = m_get(M_DONTWAIT, m->m_type); 1022 if (n == 0) 1023 break; 1024 n->m_len = min(MLEN, len); 1025 m->m_next = n; 1026 } 1027 m = m->m_next; 1028 } 1029out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) 1030 m->m_pkthdr.len = totlen; 1031} 1032 1033void 1034m_print(const struct mbuf *m) 1035{ 1036 int len; 1037 const struct mbuf *m2; 1038 1039 len = m->m_pkthdr.len; 1040 m2 = m; 1041 while (len) { 1042 printf("%p %*D\n", m2, m2->m_len, (u_char *)m2->m_data, "-"); 1043 len -= m2->m_len; 1044 m2 = m2->m_next; 1045 } 1046 return; 1047} 1048