uipc_mbuf.c revision 15543
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 * $Id: uipc_mbuf.c,v 1.17 1995/12/14 08:32:06 phk Exp $ 35 */ 36 37#include <sys/param.h> 38#include <sys/systm.h> 39#include <sys/proc.h> 40#include <sys/malloc.h> 41#define MBTYPES 42#include <sys/mbuf.h> 43#include <sys/kernel.h> 44#include <sys/syslog.h> 45#include <sys/domain.h> 46#include <sys/protosw.h> 47 48#include <vm/vm.h> 49#include <vm/vm_param.h> 50#include <vm/vm_kern.h> 51#include <vm/vm_extern.h> 52 53static void mbinit __P((void *)); 54SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL) 55 56struct mbuf *mbutl; 57char *mclrefcnt; 58struct mbstat mbstat; 59union mcluster *mclfree; 60int max_linkhdr; 61int max_protohdr; 62int max_hdr; 63int max_datalen; 64 65static void m_reclaim __P((void)); 66 67/* ARGSUSED*/ 68static void 69mbinit(dummy) 70 void *dummy; 71{ 72 int s; 73 74#if PAGE_SIZE < 4096 75#define NCL_INIT (4096/PAGE_SIZE) 76#else 77#define NCL_INIT 1 78#endif 79 s = splimp(); 80 if (m_clalloc(NCL_INIT, M_DONTWAIT) == 0) 81 goto bad; 82 splx(s); 83 return; 84bad: 85 panic("mbinit"); 86} 87 88/* 89 * Allocate some number of mbuf clusters 90 * and place on cluster free list. 91 * Must be called at splimp. 92 */ 93/* ARGSUSED */ 94int 95m_clalloc(ncl, nowait) 96 register int ncl; 97 int nowait; 98{ 99 register caddr_t p; 100 register int i; 101 int npg; 102 103 /* 104 * Once we run out of map space, it will be impossible 105 * to get any more (nothing is ever freed back to the 106 * map). 107 */ 108 if (mb_map_full) 109 return (0); 110 111 npg = ncl; 112 p = (caddr_t)kmem_malloc(mb_map, ctob(npg), 113 nowait ? M_NOWAIT : M_WAITOK); 114 /* 115 * Either the map is now full, or this is nowait and there 116 * are no pages left. 117 */ 118 if (p == NULL) 119 return (0); 120 121 ncl = ncl * PAGE_SIZE / MCLBYTES; 122 for (i = 0; i < ncl; i++) { 123 ((union mcluster *)p)->mcl_next = mclfree; 124 mclfree = (union mcluster *)p; 125 p += MCLBYTES; 126 mbstat.m_clfree++; 127 } 128 mbstat.m_clusters += ncl; 129 return (1); 130} 131 132/* 133 * When MGET failes, ask protocols to free space when short of memory, 134 * then re-attempt to allocate an mbuf. 135 */ 136struct mbuf * 137m_retry(i, t) 138 int i, t; 139{ 140 register struct mbuf *m; 141 142 m_reclaim(); 143#define m_retry(i, t) (struct mbuf *)0 144 MGET(m, i, t); 145#undef m_retry 146 if (m != NULL) 147 mbstat.m_wait++; 148 else 149 mbstat.m_drops++; 150 return (m); 151} 152 153/* 154 * As above; retry an MGETHDR. 155 */ 156struct mbuf * 157m_retryhdr(i, t) 158 int i, t; 159{ 160 register struct mbuf *m; 161 162 m_reclaim(); 163#define m_retryhdr(i, t) (struct mbuf *)0 164 MGETHDR(m, i, t); 165#undef m_retryhdr 166 if (m != NULL) 167 mbstat.m_wait++; 168 else 169 mbstat.m_drops++; 170 return (m); 171} 172 173static void 174m_reclaim() 175{ 176 register struct domain *dp; 177 register struct protosw *pr; 178 int s = splimp(); 179 180 for (dp = domains; dp; dp = dp->dom_next) 181 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) 182 if (pr->pr_drain) 183 (*pr->pr_drain)(); 184 splx(s); 185 mbstat.m_drain++; 186} 187 188/* 189 * Space allocation routines. 190 * These are also available as macros 191 * for critical paths. 192 */ 193struct mbuf * 194m_get(nowait, type) 195 int nowait, type; 196{ 197 register struct mbuf *m; 198 199 MGET(m, nowait, type); 200 return (m); 201} 202 203struct mbuf * 204m_gethdr(nowait, type) 205 int nowait, type; 206{ 207 register struct mbuf *m; 208 209 MGETHDR(m, nowait, type); 210 return (m); 211} 212 213struct mbuf * 214m_getclr(nowait, type) 215 int nowait, type; 216{ 217 register struct mbuf *m; 218 219 MGET(m, nowait, type); 220 if (m == 0) 221 return (0); 222 bzero(mtod(m, caddr_t), MLEN); 223 return (m); 224} 225 226struct mbuf * 227m_free(m) 228 struct mbuf *m; 229{ 230 register struct mbuf *n; 231 232 MFREE(m, n); 233 return (n); 234} 235 236void 237m_freem(m) 238 register struct mbuf *m; 239{ 240 register struct mbuf *n; 241 242 if (m == NULL) 243 return; 244 do { 245 MFREE(m, n); 246 m = n; 247 } while (m); 248} 249 250/* 251 * Mbuffer utility routines. 252 */ 253 254/* 255 * Lesser-used path for M_PREPEND: 256 * allocate new mbuf to prepend to chain, 257 * copy junk along. 258 */ 259struct mbuf * 260m_prepend(m, len, how) 261 register struct mbuf *m; 262 int len, how; 263{ 264 struct mbuf *mn; 265 266 MGET(mn, how, m->m_type); 267 if (mn == (struct mbuf *)NULL) { 268 m_freem(m); 269 return ((struct mbuf *)NULL); 270 } 271 if (m->m_flags & M_PKTHDR) { 272 M_COPY_PKTHDR(mn, m); 273 m->m_flags &= ~M_PKTHDR; 274 } 275 mn->m_next = m; 276 m = mn; 277 if (len < MHLEN) 278 MH_ALIGN(m, len); 279 m->m_len = len; 280 return (m); 281} 282 283/* 284 * Make a copy of an mbuf chain starting "off0" bytes from the beginning, 285 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf. 286 * The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller. 287 */ 288static int MCFail; 289 290struct mbuf * 291m_copym(m, off0, len, wait) 292 register struct mbuf *m; 293 int off0, wait; 294 register int len; 295{ 296 register struct mbuf *n, **np; 297 register int off = off0; 298 struct mbuf *top; 299 int copyhdr = 0; 300 301 if (off < 0 || len < 0) 302 panic("m_copym"); 303 if (off == 0 && m->m_flags & M_PKTHDR) 304 copyhdr = 1; 305 while (off > 0) { 306 if (m == 0) 307 panic("m_copym"); 308 if (off < m->m_len) 309 break; 310 off -= m->m_len; 311 m = m->m_next; 312 } 313 np = ⊤ 314 top = 0; 315 while (len > 0) { 316 if (m == 0) { 317 if (len != M_COPYALL) 318 panic("m_copym"); 319 break; 320 } 321 MGET(n, wait, m->m_type); 322 *np = n; 323 if (n == 0) 324 goto nospace; 325 if (copyhdr) { 326 M_COPY_PKTHDR(n, m); 327 if (len == M_COPYALL) 328 n->m_pkthdr.len -= off0; 329 else 330 n->m_pkthdr.len = len; 331 copyhdr = 0; 332 } 333 n->m_len = min(len, m->m_len - off); 334 if (m->m_flags & M_EXT) { 335 n->m_data = m->m_data + off; 336 mclrefcnt[mtocl(m->m_ext.ext_buf)]++; 337 n->m_ext = m->m_ext; 338 n->m_flags |= M_EXT; 339 } else 340 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t), 341 (unsigned)n->m_len); 342 if (len != M_COPYALL) 343 len -= n->m_len; 344 off = 0; 345 m = m->m_next; 346 np = &n->m_next; 347 } 348 if (top == 0) 349 MCFail++; 350 return (top); 351nospace: 352 m_freem(top); 353 MCFail++; 354 return (0); 355} 356 357/* 358 * Copy data from an mbuf chain starting "off" bytes from the beginning, 359 * continuing for "len" bytes, into the indicated buffer. 360 */ 361void 362m_copydata(m, off, len, cp) 363 register struct mbuf *m; 364 register int off; 365 register int len; 366 caddr_t cp; 367{ 368 register unsigned count; 369 370 if (off < 0 || len < 0) 371 panic("m_copydata"); 372 while (off > 0) { 373 if (m == 0) 374 panic("m_copydata"); 375 if (off < m->m_len) 376 break; 377 off -= m->m_len; 378 m = m->m_next; 379 } 380 while (len > 0) { 381 if (m == 0) 382 panic("m_copydata"); 383 count = min(m->m_len - off, len); 384 bcopy(mtod(m, caddr_t) + off, cp, count); 385 len -= count; 386 cp += count; 387 off = 0; 388 m = m->m_next; 389 } 390} 391 392/* 393 * Concatenate mbuf chain n to m. 394 * Both chains must be of the same type (e.g. MT_DATA). 395 * Any m_pkthdr is not updated. 396 */ 397void 398m_cat(m, n) 399 register struct mbuf *m, *n; 400{ 401 while (m->m_next) 402 m = m->m_next; 403 while (n) { 404 if (m->m_flags & M_EXT || 405 m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) { 406 /* just join the two chains */ 407 m->m_next = n; 408 return; 409 } 410 /* splat the data from one into the other */ 411 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 412 (u_int)n->m_len); 413 m->m_len += n->m_len; 414 n = m_free(n); 415 } 416} 417 418void 419m_adj(mp, req_len) 420 struct mbuf *mp; 421 int req_len; 422{ 423 register int len = req_len; 424 register struct mbuf *m; 425 register count; 426 427 if ((m = mp) == NULL) 428 return; 429 if (len >= 0) { 430 /* 431 * Trim from head. 432 */ 433 while (m != NULL && len > 0) { 434 if (m->m_len <= len) { 435 len -= m->m_len; 436 m->m_len = 0; 437 m = m->m_next; 438 } else { 439 m->m_len -= len; 440 m->m_data += len; 441 len = 0; 442 } 443 } 444 m = mp; 445 if (mp->m_flags & M_PKTHDR) 446 m->m_pkthdr.len -= (req_len - len); 447 } else { 448 /* 449 * Trim from tail. Scan the mbuf chain, 450 * calculating its length and finding the last mbuf. 451 * If the adjustment only affects this mbuf, then just 452 * adjust and return. Otherwise, rescan and truncate 453 * after the remaining size. 454 */ 455 len = -len; 456 count = 0; 457 for (;;) { 458 count += m->m_len; 459 if (m->m_next == (struct mbuf *)0) 460 break; 461 m = m->m_next; 462 } 463 if (m->m_len >= len) { 464 m->m_len -= len; 465 if (mp->m_flags & M_PKTHDR) 466 mp->m_pkthdr.len -= len; 467 return; 468 } 469 count -= len; 470 if (count < 0) 471 count = 0; 472 /* 473 * Correct length for chain is "count". 474 * Find the mbuf with last data, adjust its length, 475 * and toss data from remaining mbufs on chain. 476 */ 477 m = mp; 478 if (m->m_flags & M_PKTHDR) 479 m->m_pkthdr.len = count; 480 for (; m; m = m->m_next) { 481 if (m->m_len >= count) { 482 m->m_len = count; 483 break; 484 } 485 count -= m->m_len; 486 } 487 while (m->m_next) 488 (m = m->m_next) ->m_len = 0; 489 } 490} 491 492/* 493 * Rearange an mbuf chain so that len bytes are contiguous 494 * and in the data area of an mbuf (so that mtod and dtom 495 * will work for a structure of size len). Returns the resulting 496 * mbuf chain on success, frees it and returns null on failure. 497 * If there is room, it will add up to max_protohdr-len extra bytes to the 498 * contiguous region in an attempt to avoid being called next time. 499 */ 500static int MPFail; 501 502struct mbuf * 503m_pullup(n, len) 504 register struct mbuf *n; 505 int len; 506{ 507 register struct mbuf *m; 508 register int count; 509 int space; 510 511 /* 512 * If first mbuf has no cluster, and has room for len bytes 513 * without shifting current data, pullup into it, 514 * otherwise allocate a new mbuf to prepend to the chain. 515 */ 516 if ((n->m_flags & M_EXT) == 0 && 517 n->m_data + len < &n->m_dat[MLEN] && n->m_next) { 518 if (n->m_len >= len) 519 return (n); 520 m = n; 521 n = n->m_next; 522 len -= m->m_len; 523 } else { 524 if (len > MHLEN) 525 goto bad; 526 MGET(m, M_DONTWAIT, n->m_type); 527 if (m == 0) 528 goto bad; 529 m->m_len = 0; 530 if (n->m_flags & M_PKTHDR) { 531 M_COPY_PKTHDR(m, n); 532 n->m_flags &= ~M_PKTHDR; 533 } 534 } 535 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 536 do { 537 count = min(min(max(len, max_protohdr), space), n->m_len); 538 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 539 (unsigned)count); 540 len -= count; 541 m->m_len += count; 542 n->m_len -= count; 543 space -= count; 544 if (n->m_len) 545 n->m_data += count; 546 else 547 n = m_free(n); 548 } while (len > 0 && n); 549 if (len > 0) { 550 (void) m_free(m); 551 goto bad; 552 } 553 m->m_next = n; 554 return (m); 555bad: 556 m_freem(n); 557 MPFail++; 558 return (0); 559} 560 561/* 562 * Partition an mbuf chain in two pieces, returning the tail -- 563 * all but the first len0 bytes. In case of failure, it returns NULL and 564 * attempts to restore the chain to its original state. 565 */ 566struct mbuf * 567m_split(m0, len0, wait) 568 register struct mbuf *m0; 569 int len0, wait; 570{ 571 register struct mbuf *m, *n; 572 unsigned len = len0, remain; 573 574 for (m = m0; m && len > m->m_len; m = m->m_next) 575 len -= m->m_len; 576 if (m == 0) 577 return (0); 578 remain = m->m_len - len; 579 if (m0->m_flags & M_PKTHDR) { 580 MGETHDR(n, wait, m0->m_type); 581 if (n == 0) 582 return (0); 583 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; 584 n->m_pkthdr.len = m0->m_pkthdr.len - len0; 585 m0->m_pkthdr.len = len0; 586 if (m->m_flags & M_EXT) 587 goto extpacket; 588 if (remain > MHLEN) { 589 /* m can't be the lead packet */ 590 MH_ALIGN(n, 0); 591 n->m_next = m_split(m, len, wait); 592 if (n->m_next == 0) { 593 (void) m_free(n); 594 return (0); 595 } else 596 return (n); 597 } else 598 MH_ALIGN(n, remain); 599 } else if (remain == 0) { 600 n = m->m_next; 601 m->m_next = 0; 602 return (n); 603 } else { 604 MGET(n, wait, m->m_type); 605 if (n == 0) 606 return (0); 607 M_ALIGN(n, remain); 608 } 609extpacket: 610 if (m->m_flags & M_EXT) { 611 n->m_flags |= M_EXT; 612 n->m_ext = m->m_ext; 613 mclrefcnt[mtocl(m->m_ext.ext_buf)]++; 614 m->m_ext.ext_size = 0; /* For Accounting XXXXXX danger */ 615 n->m_data = m->m_data + len; 616 } else { 617 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain); 618 } 619 n->m_len = remain; 620 m->m_len = len; 621 n->m_next = m->m_next; 622 m->m_next = 0; 623 return (n); 624} 625/* 626 * Routine to copy from device local memory into mbufs. 627 */ 628struct mbuf * 629m_devget(buf, totlen, off0, ifp, copy) 630 char *buf; 631 int totlen, off0; 632 struct ifnet *ifp; 633 void (*copy) __P((char *from, caddr_t to, u_int len)); 634{ 635 register struct mbuf *m; 636 struct mbuf *top = 0, **mp = ⊤ 637 register int off = off0, len; 638 register char *cp; 639 char *epkt; 640 641 cp = buf; 642 epkt = cp + totlen; 643 if (off) { 644 cp += off + 2 * sizeof(u_short); 645 totlen -= 2 * sizeof(u_short); 646 } 647 MGETHDR(m, M_DONTWAIT, MT_DATA); 648 if (m == 0) 649 return (0); 650 m->m_pkthdr.rcvif = ifp; 651 m->m_pkthdr.len = totlen; 652 m->m_len = MHLEN; 653 654 while (totlen > 0) { 655 if (top) { 656 MGET(m, M_DONTWAIT, MT_DATA); 657 if (m == 0) { 658 m_freem(top); 659 return (0); 660 } 661 m->m_len = MLEN; 662 } 663 len = min(totlen, epkt - cp); 664 if (len >= MINCLSIZE) { 665 MCLGET(m, M_DONTWAIT); 666 if (m->m_flags & M_EXT) 667 m->m_len = len = min(len, MCLBYTES); 668 else 669 len = m->m_len; 670 } else { 671 /* 672 * Place initial small packet/header at end of mbuf. 673 */ 674 if (len < m->m_len) { 675 if (top == 0 && len + max_linkhdr <= m->m_len) 676 m->m_data += max_linkhdr; 677 m->m_len = len; 678 } else 679 len = m->m_len; 680 } 681 if (copy) 682 copy(cp, mtod(m, caddr_t), (unsigned)len); 683 else 684 bcopy(cp, mtod(m, caddr_t), (unsigned)len); 685 cp += len; 686 *mp = m; 687 mp = &m->m_next; 688 totlen -= len; 689 if (cp == epkt) 690 cp = buf; 691 } 692 return (top); 693} 694 695/* 696 * Copy data from a buffer back into the indicated mbuf chain, 697 * starting "off" bytes from the beginning, extending the mbuf 698 * chain if necessary. 699 */ 700void 701m_copyback(m0, off, len, cp) 702 struct mbuf *m0; 703 register int off; 704 register int len; 705 caddr_t cp; 706{ 707 register int mlen; 708 register struct mbuf *m = m0, *n; 709 int totlen = 0; 710 711 if (m0 == 0) 712 return; 713 while (off > (mlen = m->m_len)) { 714 off -= mlen; 715 totlen += mlen; 716 if (m->m_next == 0) { 717 n = m_getclr(M_DONTWAIT, m->m_type); 718 if (n == 0) 719 goto out; 720 n->m_len = min(MLEN, len + off); 721 m->m_next = n; 722 } 723 m = m->m_next; 724 } 725 while (len > 0) { 726 mlen = min (m->m_len - off, len); 727 bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen); 728 cp += mlen; 729 len -= mlen; 730 mlen += off; 731 off = 0; 732 totlen += mlen; 733 if (len == 0) 734 break; 735 if (m->m_next == 0) { 736 n = m_get(M_DONTWAIT, m->m_type); 737 if (n == 0) 738 break; 739 n->m_len = min(MLEN, len); 740 m->m_next = n; 741 } 742 m = m->m_next; 743 } 744out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) 745 m->m_pkthdr.len = totlen; 746} 747