uipc_mbuf.c revision 1541
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 */ 35 36#include <sys/param.h> 37#include <sys/systm.h> 38#include <sys/proc.h> 39#include <sys/malloc.h> 40#include <sys/map.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 50extern vm_map_t mb_map; 51struct mbuf *mbutl; 52char *mclrefcnt; 53 54mbinit() 55{ 56 int s; 57 58#if CLBYTES < 4096 59#define NCL_INIT (4096/CLBYTES) 60#else 61#define NCL_INIT 1 62#endif 63 s = splimp(); 64 if (m_clalloc(NCL_INIT, M_DONTWAIT) == 0) 65 goto bad; 66 splx(s); 67 return; 68bad: 69 panic("mbinit"); 70} 71 72/* 73 * Allocate some number of mbuf clusters 74 * and place on cluster free list. 75 * Must be called at splimp. 76 */ 77/* ARGSUSED */ 78m_clalloc(ncl, nowait) 79 register int ncl; 80 int nowait; 81{ 82 static int logged; 83 register caddr_t p; 84 register int i; 85 int npg; 86 87 npg = ncl * CLSIZE; 88 p = (caddr_t)kmem_malloc(mb_map, ctob(npg), !nowait); 89 if (p == NULL) { 90 if (logged == 0) { 91 logged++; 92 log(LOG_ERR, "mb_map full\n"); 93 } 94 return (0); 95 } 96 ncl = ncl * CLBYTES / MCLBYTES; 97 for (i = 0; i < ncl; i++) { 98 ((union mcluster *)p)->mcl_next = mclfree; 99 mclfree = (union mcluster *)p; 100 p += MCLBYTES; 101 mbstat.m_clfree++; 102 } 103 mbstat.m_clusters += ncl; 104 return (1); 105} 106 107/* 108 * When MGET failes, ask protocols to free space when short of memory, 109 * then re-attempt to allocate an mbuf. 110 */ 111struct mbuf * 112m_retry(i, t) 113 int i, t; 114{ 115 register struct mbuf *m; 116 117 m_reclaim(); 118#define m_retry(i, t) (struct mbuf *)0 119 MGET(m, i, t); 120#undef m_retry 121 return (m); 122} 123 124/* 125 * As above; retry an MGETHDR. 126 */ 127struct mbuf * 128m_retryhdr(i, t) 129 int i, t; 130{ 131 register struct mbuf *m; 132 133 m_reclaim(); 134#define m_retryhdr(i, t) (struct mbuf *)0 135 MGETHDR(m, i, t); 136#undef m_retryhdr 137 return (m); 138} 139 140m_reclaim() 141{ 142 register struct domain *dp; 143 register struct protosw *pr; 144 int s = splimp(); 145 146 for (dp = domains; dp; dp = dp->dom_next) 147 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) 148 if (pr->pr_drain) 149 (*pr->pr_drain)(); 150 splx(s); 151 mbstat.m_drain++; 152} 153 154/* 155 * Space allocation routines. 156 * These are also available as macros 157 * for critical paths. 158 */ 159struct mbuf * 160m_get(nowait, type) 161 int nowait, type; 162{ 163 register struct mbuf *m; 164 165 MGET(m, nowait, type); 166 return (m); 167} 168 169struct mbuf * 170m_gethdr(nowait, type) 171 int nowait, type; 172{ 173 register struct mbuf *m; 174 175 MGETHDR(m, nowait, type); 176 return (m); 177} 178 179struct mbuf * 180m_getclr(nowait, type) 181 int nowait, type; 182{ 183 register struct mbuf *m; 184 185 MGET(m, nowait, type); 186 if (m == 0) 187 return (0); 188 bzero(mtod(m, caddr_t), MLEN); 189 return (m); 190} 191 192struct mbuf * 193m_free(m) 194 struct mbuf *m; 195{ 196 register struct mbuf *n; 197 198 MFREE(m, n); 199 return (n); 200} 201 202void 203m_freem(m) 204 register struct mbuf *m; 205{ 206 register struct mbuf *n; 207 208 if (m == NULL) 209 return; 210 do { 211 MFREE(m, n); 212 } while (m = n); 213} 214 215/* 216 * Mbuffer utility routines. 217 */ 218 219/* 220 * Lesser-used path for M_PREPEND: 221 * allocate new mbuf to prepend to chain, 222 * copy junk along. 223 */ 224struct mbuf * 225m_prepend(m, len, how) 226 register struct mbuf *m; 227 int len, how; 228{ 229 struct mbuf *mn; 230 231 MGET(mn, how, m->m_type); 232 if (mn == (struct mbuf *)NULL) { 233 m_freem(m); 234 return ((struct mbuf *)NULL); 235 } 236 if (m->m_flags & M_PKTHDR) { 237 M_COPY_PKTHDR(mn, m); 238 m->m_flags &= ~M_PKTHDR; 239 } 240 mn->m_next = m; 241 m = mn; 242 if (len < MHLEN) 243 MH_ALIGN(m, len); 244 m->m_len = len; 245 return (m); 246} 247 248/* 249 * Make a copy of an mbuf chain starting "off0" bytes from the beginning, 250 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf. 251 * The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller. 252 */ 253int MCFail; 254 255struct mbuf * 256m_copym(m, off0, len, wait) 257 register struct mbuf *m; 258 int off0, wait; 259 register int len; 260{ 261 register struct mbuf *n, **np; 262 register int off = off0; 263 struct mbuf *top; 264 int copyhdr = 0; 265 266 if (off < 0 || len < 0) 267 panic("m_copym"); 268 if (off == 0 && m->m_flags & M_PKTHDR) 269 copyhdr = 1; 270 while (off > 0) { 271 if (m == 0) 272 panic("m_copym"); 273 if (off < m->m_len) 274 break; 275 off -= m->m_len; 276 m = m->m_next; 277 } 278 np = ⊤ 279 top = 0; 280 while (len > 0) { 281 if (m == 0) { 282 if (len != M_COPYALL) 283 panic("m_copym"); 284 break; 285 } 286 MGET(n, wait, m->m_type); 287 *np = n; 288 if (n == 0) 289 goto nospace; 290 if (copyhdr) { 291 M_COPY_PKTHDR(n, m); 292 if (len == M_COPYALL) 293 n->m_pkthdr.len -= off0; 294 else 295 n->m_pkthdr.len = len; 296 copyhdr = 0; 297 } 298 n->m_len = min(len, m->m_len - off); 299 if (m->m_flags & M_EXT) { 300 n->m_data = m->m_data + off; 301 mclrefcnt[mtocl(m->m_ext.ext_buf)]++; 302 n->m_ext = m->m_ext; 303 n->m_flags |= M_EXT; 304 } else 305 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t), 306 (unsigned)n->m_len); 307 if (len != M_COPYALL) 308 len -= n->m_len; 309 off = 0; 310 m = m->m_next; 311 np = &n->m_next; 312 } 313 if (top == 0) 314 MCFail++; 315 return (top); 316nospace: 317 m_freem(top); 318 MCFail++; 319 return (0); 320} 321 322/* 323 * Copy data from an mbuf chain starting "off" bytes from the beginning, 324 * continuing for "len" bytes, into the indicated buffer. 325 */ 326m_copydata(m, off, len, cp) 327 register struct mbuf *m; 328 register int off; 329 register int len; 330 caddr_t cp; 331{ 332 register unsigned count; 333 334 if (off < 0 || len < 0) 335 panic("m_copydata"); 336 while (off > 0) { 337 if (m == 0) 338 panic("m_copydata"); 339 if (off < m->m_len) 340 break; 341 off -= m->m_len; 342 m = m->m_next; 343 } 344 while (len > 0) { 345 if (m == 0) 346 panic("m_copydata"); 347 count = min(m->m_len - off, len); 348 bcopy(mtod(m, caddr_t) + off, cp, count); 349 len -= count; 350 cp += count; 351 off = 0; 352 m = m->m_next; 353 } 354} 355 356/* 357 * Concatenate mbuf chain n to m. 358 * Both chains must be of the same type (e.g. MT_DATA). 359 * Any m_pkthdr is not updated. 360 */ 361m_cat(m, n) 362 register struct mbuf *m, *n; 363{ 364 while (m->m_next) 365 m = m->m_next; 366 while (n) { 367 if (m->m_flags & M_EXT || 368 m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) { 369 /* just join the two chains */ 370 m->m_next = n; 371 return; 372 } 373 /* splat the data from one into the other */ 374 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 375 (u_int)n->m_len); 376 m->m_len += n->m_len; 377 n = m_free(n); 378 } 379} 380 381m_adj(mp, req_len) 382 struct mbuf *mp; 383 int req_len; 384{ 385 register int len = req_len; 386 register struct mbuf *m; 387 register count; 388 389 if ((m = mp) == NULL) 390 return; 391 if (len >= 0) { 392 /* 393 * Trim from head. 394 */ 395 while (m != NULL && len > 0) { 396 if (m->m_len <= len) { 397 len -= m->m_len; 398 m->m_len = 0; 399 m = m->m_next; 400 } else { 401 m->m_len -= len; 402 m->m_data += len; 403 len = 0; 404 } 405 } 406 m = mp; 407 if (mp->m_flags & M_PKTHDR) 408 m->m_pkthdr.len -= (req_len - len); 409 } else { 410 /* 411 * Trim from tail. Scan the mbuf chain, 412 * calculating its length and finding the last mbuf. 413 * If the adjustment only affects this mbuf, then just 414 * adjust and return. Otherwise, rescan and truncate 415 * after the remaining size. 416 */ 417 len = -len; 418 count = 0; 419 for (;;) { 420 count += m->m_len; 421 if (m->m_next == (struct mbuf *)0) 422 break; 423 m = m->m_next; 424 } 425 if (m->m_len >= len) { 426 m->m_len -= len; 427 if (mp->m_flags & M_PKTHDR) 428 mp->m_pkthdr.len -= len; 429 return; 430 } 431 count -= len; 432 if (count < 0) 433 count = 0; 434 /* 435 * Correct length for chain is "count". 436 * Find the mbuf with last data, adjust its length, 437 * and toss data from remaining mbufs on chain. 438 */ 439 m = mp; 440 if (m->m_flags & M_PKTHDR) 441 m->m_pkthdr.len = count; 442 for (; m; m = m->m_next) { 443 if (m->m_len >= count) { 444 m->m_len = count; 445 break; 446 } 447 count -= m->m_len; 448 } 449 while (m = m->m_next) 450 m->m_len = 0; 451 } 452} 453 454/* 455 * Rearange an mbuf chain so that len bytes are contiguous 456 * and in the data area of an mbuf (so that mtod and dtom 457 * will work for a structure of size len). Returns the resulting 458 * mbuf chain on success, frees it and returns null on failure. 459 * If there is room, it will add up to max_protohdr-len extra bytes to the 460 * contiguous region in an attempt to avoid being called next time. 461 */ 462int MPFail; 463 464struct mbuf * 465m_pullup(n, len) 466 register struct mbuf *n; 467 int len; 468{ 469 register struct mbuf *m; 470 register int count; 471 int space; 472 473 /* 474 * If first mbuf has no cluster, and has room for len bytes 475 * without shifting current data, pullup into it, 476 * otherwise allocate a new mbuf to prepend to the chain. 477 */ 478 if ((n->m_flags & M_EXT) == 0 && 479 n->m_data + len < &n->m_dat[MLEN] && n->m_next) { 480 if (n->m_len >= len) 481 return (n); 482 m = n; 483 n = n->m_next; 484 len -= m->m_len; 485 } else { 486 if (len > MHLEN) 487 goto bad; 488 MGET(m, M_DONTWAIT, n->m_type); 489 if (m == 0) 490 goto bad; 491 m->m_len = 0; 492 if (n->m_flags & M_PKTHDR) { 493 M_COPY_PKTHDR(m, n); 494 n->m_flags &= ~M_PKTHDR; 495 } 496 } 497 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 498 do { 499 count = min(min(max(len, max_protohdr), space), n->m_len); 500 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 501 (unsigned)count); 502 len -= count; 503 m->m_len += count; 504 n->m_len -= count; 505 space -= count; 506 if (n->m_len) 507 n->m_data += count; 508 else 509 n = m_free(n); 510 } while (len > 0 && n); 511 if (len > 0) { 512 (void) m_free(m); 513 goto bad; 514 } 515 m->m_next = n; 516 return (m); 517bad: 518 m_freem(n); 519 MPFail++; 520 return (0); 521} 522 523/* 524 * Partition an mbuf chain in two pieces, returning the tail -- 525 * all but the first len0 bytes. In case of failure, it returns NULL and 526 * attempts to restore the chain to its original state. 527 */ 528struct mbuf * 529m_split(m0, len0, wait) 530 register struct mbuf *m0; 531 int len0, wait; 532{ 533 register struct mbuf *m, *n; 534 unsigned len = len0, remain; 535 536 for (m = m0; m && len > m->m_len; m = m->m_next) 537 len -= m->m_len; 538 if (m == 0) 539 return (0); 540 remain = m->m_len - len; 541 if (m0->m_flags & M_PKTHDR) { 542 MGETHDR(n, wait, m0->m_type); 543 if (n == 0) 544 return (0); 545 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; 546 n->m_pkthdr.len = m0->m_pkthdr.len - len0; 547 m0->m_pkthdr.len = len0; 548 if (m->m_flags & M_EXT) 549 goto extpacket; 550 if (remain > MHLEN) { 551 /* m can't be the lead packet */ 552 MH_ALIGN(n, 0); 553 n->m_next = m_split(m, len, wait); 554 if (n->m_next == 0) { 555 (void) m_free(n); 556 return (0); 557 } else 558 return (n); 559 } else 560 MH_ALIGN(n, remain); 561 } else if (remain == 0) { 562 n = m->m_next; 563 m->m_next = 0; 564 return (n); 565 } else { 566 MGET(n, wait, m->m_type); 567 if (n == 0) 568 return (0); 569 M_ALIGN(n, remain); 570 } 571extpacket: 572 if (m->m_flags & M_EXT) { 573 n->m_flags |= M_EXT; 574 n->m_ext = m->m_ext; 575 mclrefcnt[mtocl(m->m_ext.ext_buf)]++; 576 m->m_ext.ext_size = 0; /* For Accounting XXXXXX danger */ 577 n->m_data = m->m_data + len; 578 } else { 579 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain); 580 } 581 n->m_len = remain; 582 m->m_len = len; 583 n->m_next = m->m_next; 584 m->m_next = 0; 585 return (n); 586} 587/* 588 * Routine to copy from device local memory into mbufs. 589 */ 590struct mbuf * 591m_devget(buf, totlen, off0, ifp, copy) 592 char *buf; 593 int totlen, off0; 594 struct ifnet *ifp; 595 void (*copy)(); 596{ 597 register struct mbuf *m; 598 struct mbuf *top = 0, **mp = ⊤ 599 register int off = off0, len; 600 register char *cp; 601 char *epkt; 602 603 cp = buf; 604 epkt = cp + totlen; 605 if (off) { 606 cp += off + 2 * sizeof(u_short); 607 totlen -= 2 * sizeof(u_short); 608 } 609 MGETHDR(m, M_DONTWAIT, MT_DATA); 610 if (m == 0) 611 return (0); 612 m->m_pkthdr.rcvif = ifp; 613 m->m_pkthdr.len = totlen; 614 m->m_len = MHLEN; 615 616 while (totlen > 0) { 617 if (top) { 618 MGET(m, M_DONTWAIT, MT_DATA); 619 if (m == 0) { 620 m_freem(top); 621 return (0); 622 } 623 m->m_len = MLEN; 624 } 625 len = min(totlen, epkt - cp); 626 if (len >= MINCLSIZE) { 627 MCLGET(m, M_DONTWAIT); 628 if (m->m_flags & M_EXT) 629 m->m_len = len = min(len, MCLBYTES); 630 else 631 len = m->m_len; 632 } else { 633 /* 634 * Place initial small packet/header at end of mbuf. 635 */ 636 if (len < m->m_len) { 637 if (top == 0 && len + max_linkhdr <= m->m_len) 638 m->m_data += max_linkhdr; 639 m->m_len = len; 640 } else 641 len = m->m_len; 642 } 643 if (copy) 644 copy(cp, mtod(m, caddr_t), (unsigned)len); 645 else 646 bcopy(cp, mtod(m, caddr_t), (unsigned)len); 647 cp += len; 648 *mp = m; 649 mp = &m->m_next; 650 totlen -= len; 651 if (cp == epkt) 652 cp = buf; 653 } 654 return (top); 655} 656