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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_mac.h" 36 #include "opt_param.h" 37 #include "opt_mbuf_stress_test.h" 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/kernel.h> 42 #include <sys/limits.h> 43 #include <sys/lock.h> 44 #include <sys/mac.h> 45 #include <sys/malloc.h> 46 #include <sys/mbuf.h> 47 #include <sys/sysctl.h> 48 #include <sys/domain.h> 49 #include <sys/protosw.h> 50 #include <sys/uio.h> 51 52 int max_linkhdr; 53 int max_protohdr; 54 int max_hdr; 55 int max_datalen; 56 #ifdef MBUF_STRESS_TEST 57 int m_defragpackets; 58 int m_defragbytes; 59 int m_defraguseless; 60 int m_defragfailure; 61 int m_defragrandomfailures; 62 #endif 63 64 /* 65 * sysctl(8) exported objects 66 */ 67 SYSCTL_DECL(_kern_ipc); 68 SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW, 69 &max_linkhdr, 0, ""); 70 SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW, 71 &max_protohdr, 0, ""); 72 SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0, ""); 73 SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW, 74 &max_datalen, 0, ""); 75 #ifdef MBUF_STRESS_TEST 76 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD, 77 &m_defragpackets, 0, ""); 78 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD, 79 &m_defragbytes, 0, ""); 80 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD, 81 &m_defraguseless, 0, ""); 82 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD, 83 &m_defragfailure, 0, ""); 84 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW, 85 &m_defragrandomfailures, 0, ""); 86 #endif 87 88 /* 89 * Malloc-type for external ext_buf ref counts. 90 */ 91 static MALLOC_DEFINE(M_MBUF, "mbextcnt", "mbuf external ref counts"); 92 93 /* 94 * Allocate a given length worth of mbufs and/or clusters (whatever fits 95 * best) and return a pointer to the top of the allocated chain. If an 96 * existing mbuf chain is provided, then we will append the new chain 97 * to the existing one but still return the top of the newly allocated 98 * chain. 99 */ 100 struct mbuf * 101 m_getm(struct mbuf *m, int len, int how, short type) 102 { 103 struct mbuf *mb, *top, *cur, *mtail; 104 int num, rem; 105 int i; 106 107 KASSERT(len >= 0, ("m_getm(): len is < 0")); 108 109 /* If m != NULL, we will append to the end of that chain. */ 110 if (m != NULL) 111 for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next); 112 else 113 mtail = NULL; 114 115 /* 116 * Calculate how many mbufs+clusters ("packets") we need and how much 117 * leftover there is after that and allocate the first mbuf+cluster 118 * if required. 119 */ 120 num = len / MCLBYTES; 121 rem = len % MCLBYTES; 122 top = cur = NULL; 123 if (num > 0) { 124 if ((top = cur = m_getcl(how, type, 0)) == NULL) 125 goto failed; 126 top->m_len = 0; 127 } 128 num--; 129 130 for (i = 0; i < num; i++) { 131 mb = m_getcl(how, type, 0); 132 if (mb == NULL) 133 goto failed; 134 mb->m_len = 0; 135 cur = (cur->m_next = mb); 136 } 137 if (rem > 0) { 138 mb = (rem > MINCLSIZE) ? 139 m_getcl(how, type, 0) : m_get(how, type); 140 if (mb == NULL) 141 goto failed; 142 mb->m_len = 0; 143 if (cur == NULL) 144 top = mb; 145 else 146 cur->m_next = mb; 147 } 148 149 if (mtail != NULL) 150 mtail->m_next = top; 151 return top; 152 failed: 153 if (top != NULL) 154 m_freem(top); 155 return NULL; 156 } 157 158 /* 159 * Free an entire chain of mbufs and associated external buffers, if 160 * applicable. 161 */ 162 void 163 m_freem(struct mbuf *mb) 164 { 165 166 while (mb != NULL) 167 mb = m_free(mb); 168 } 169 170 /*- 171 * Configure a provided mbuf to refer to the provided external storage 172 * buffer and setup a reference count for said buffer. If the setting 173 * up of the reference count fails, the M_EXT bit will not be set. If 174 * successfull, the M_EXT bit is set in the mbuf's flags. 175 * 176 * Arguments: 177 * mb The existing mbuf to which to attach the provided buffer. 178 * buf The address of the provided external storage buffer. 179 * size The size of the provided buffer. 180 * freef A pointer to a routine that is responsible for freeing the 181 * provided external storage buffer. 182 * args A pointer to an argument structure (of any type) to be passed 183 * to the provided freef routine (may be NULL). 184 * flags Any other flags to be passed to the provided mbuf. 185 * type The type that the external storage buffer should be 186 * labeled with. 187 * 188 * Returns: 189 * Nothing. 190 */ 191 void 192 m_extadd(struct mbuf *mb, caddr_t buf, u_int size, 193 void (*freef)(void *, void *), void *args, int flags, int type) 194 { 195 u_int *ref_cnt = NULL; 196 197 /* XXX Shouldn't be adding EXT_CLUSTER with this API */ 198 if (type == EXT_CLUSTER) 199 ref_cnt = (u_int *)uma_find_refcnt(zone_clust, 200 mb->m_ext.ext_buf); 201 else if (type == EXT_EXTREF) 202 ref_cnt = __DEVOLATILE(u_int *, mb->m_ext.ref_cnt); 203 mb->m_ext.ref_cnt = (ref_cnt == NULL) ? 204 malloc(sizeof(u_int), M_MBUF, M_NOWAIT) : (u_int *)ref_cnt; 205 if (mb->m_ext.ref_cnt != NULL) { 206 *(mb->m_ext.ref_cnt) = 1; 207 mb->m_flags |= (M_EXT | flags); 208 mb->m_ext.ext_buf = buf; 209 mb->m_data = mb->m_ext.ext_buf; 210 mb->m_ext.ext_size = size; 211 mb->m_ext.ext_free = freef; 212 mb->m_ext.ext_args = args; 213 mb->m_ext.ext_type = type; 214 } 215 } 216 217 /* 218 * Non-directly-exported function to clean up after mbufs with M_EXT 219 * storage attached to them if the reference count hits 0. 220 */ 221 void 222 mb_free_ext(struct mbuf *m) 223 { 224 u_int cnt; 225 int dofree; 226 227 /* Account for lazy ref count assign. */ 228 if (m->m_ext.ref_cnt == NULL) 229 dofree = 1; 230 else 231 dofree = 0; 232 233 /* 234 * This is tricky. We need to make sure to decrement the 235 * refcount in a safe way but to also clean up if we're the 236 * last reference. This method seems to do it without race. 237 */ 238 while (dofree == 0) { 239 cnt = *(m->m_ext.ref_cnt); 240 if (atomic_cmpset_int(m->m_ext.ref_cnt, cnt, cnt - 1)) { 241 if (cnt == 1) 242 dofree = 1; 243 break; 244 } 245 } 246 247 if (dofree) { 248 /* 249 * Do the free, should be safe. 250 */ 251 if (m->m_ext.ext_type == EXT_PACKET) { 252 uma_zfree(zone_pack, m); 253 return; 254 } else if (m->m_ext.ext_type == EXT_CLUSTER) { 255 uma_zfree(zone_clust, m->m_ext.ext_buf); 256 m->m_ext.ext_buf = NULL; 257 } else { 258 (*(m->m_ext.ext_free))(m->m_ext.ext_buf, 259 m->m_ext.ext_args); 260 if (m->m_ext.ext_type != EXT_EXTREF) { 261 if (m->m_ext.ref_cnt != NULL) 262 free(__DEVOLATILE(u_int *, 263 m->m_ext.ref_cnt), M_MBUF); 264 m->m_ext.ref_cnt = NULL; 265 } 266 m->m_ext.ext_buf = NULL; 267 } 268 } 269 uma_zfree(zone_mbuf, m); 270 } 271 272 /* 273 * Clean up mbuf (chain) from any tags and packet headers. 274 * If "all" is set then the first mbuf in the chain will be 275 * cleaned too. 276 */ 277 void 278 m_demote(struct mbuf *m0, int all) 279 { 280 struct mbuf *m; 281 282 for (m = all ? m0 : m0->m_next; m != NULL; m = m->m_next) { 283 if (m->m_flags & M_PKTHDR) { 284 m_tag_delete_chain(m, NULL); 285 m->m_flags &= ~M_PKTHDR; 286 bzero(&m->m_pkthdr, sizeof(struct pkthdr)); 287 } 288 if (m->m_type == MT_HEADER) 289 m->m_type = MT_DATA; 290 if (m != m0 && m->m_nextpkt != NULL) 291 m->m_nextpkt = NULL; 292 m->m_flags = m->m_flags & (M_EXT|M_EOR|M_RDONLY|M_FREELIST); 293 } 294 } 295 296 /* 297 * Sanity checks on mbuf (chain) for use in KASSERT() and general 298 * debugging. 299 * Returns 0 or panics when bad and 1 on all tests passed. 300 * Sanitize, 0 to run M_SANITY_ACTION, 1 to garble things so they 301 * blow up later. 302 */ 303 int 304 m_sanity(struct mbuf *m0, int sanitize) 305 { 306 struct mbuf *m; 307 caddr_t a, b; 308 int pktlen = 0; 309 310 #define M_SANITY_ACTION(s) return (0) 311 /* #define M_SANITY_ACTION(s) panic("mbuf %p: " s, m) */ 312 313 for (m = m0; m != NULL; m = m->m_next) { 314 /* 315 * Basic pointer checks. If any of these fails then some 316 * unrelated kernel memory before or after us is trashed. 317 * No way to recover from that. 318 */ 319 a = ((m->m_flags & M_EXT) ? m->m_ext.ext_buf : 320 ((m->m_flags & M_PKTHDR) ? (caddr_t)(&m->m_pktdat) : 321 (caddr_t)(&m->m_dat)) ); 322 b = (caddr_t)(a + (m->m_flags & M_EXT ? m->m_ext.ext_size : 323 ((m->m_flags & M_PKTHDR) ? MHLEN : MLEN))); 324 if ((caddr_t)m->m_data < a) 325 M_SANITY_ACTION("m_data outside mbuf data range left"); 326 if ((caddr_t)m->m_data > b) 327 M_SANITY_ACTION("m_data outside mbuf data range right"); 328 if ((caddr_t)m->m_data + m->m_len > b) 329 M_SANITY_ACTION("m_data + m_len exeeds mbuf space"); 330 if ((m->m_flags & M_PKTHDR) && m->m_pkthdr.header) { 331 if ((caddr_t)m->m_pkthdr.header < a || 332 (caddr_t)m->m_pkthdr.header > b) 333 M_SANITY_ACTION("m_pkthdr.header outside mbuf data range"); 334 } 335 336 /* m->m_nextpkt may only be set on first mbuf in chain. */ 337 if (m != m0 && m->m_nextpkt != NULL) { 338 if (sanitize) { 339 m_freem(m->m_nextpkt); 340 m->m_nextpkt = (struct mbuf *)0xDEADC0DE; 341 } else 342 M_SANITY_ACTION("m->m_nextpkt on in-chain mbuf"); 343 } 344 345 /* correct type correlations. */ 346 if (m->m_type == MT_HEADER && !(m->m_flags & M_PKTHDR)) { 347 if (sanitize) 348 m->m_type = MT_DATA; 349 else 350 M_SANITY_ACTION("MT_HEADER set but not M_PKTHDR"); 351 } 352 353 /* packet length (not mbuf length!) calculation */ 354 if (m0->m_flags & M_PKTHDR) 355 pktlen += m->m_len; 356 357 /* m_tags may only be attached to first mbuf in chain. */ 358 if (m != m0 && m->m_flags & M_PKTHDR && 359 !SLIST_EMPTY(&m->m_pkthdr.tags)) { 360 if (sanitize) { 361 m_tag_delete_chain(m, NULL); 362 /* put in 0xDEADC0DE perhaps? */ 363 } else 364 M_SANITY_ACTION("m_tags on in-chain mbuf"); 365 } 366 367 /* M_PKTHDR may only be set on first mbuf in chain */ 368 if (m != m0 && m->m_flags & M_PKTHDR) { 369 if (sanitize) { 370 bzero(&m->m_pkthdr, sizeof(m->m_pkthdr)); 371 m->m_flags &= ~M_PKTHDR; 372 /* put in 0xDEADCODE and leave hdr flag in */ 373 } else 374 M_SANITY_ACTION("M_PKTHDR on in-chain mbuf"); 375 } 376 } 377 m = m0; 378 if (pktlen && pktlen != m->m_pkthdr.len) { 379 if (sanitize) 380 m->m_pkthdr.len = 0; 381 else 382 M_SANITY_ACTION("m_pkthdr.len != mbuf chain length"); 383 } 384 return 1; 385 386 #undef M_SANITY_ACTION 387 } 388 389 390 /* 391 * "Move" mbuf pkthdr from "from" to "to". 392 * "from" must have M_PKTHDR set, and "to" must be empty. 393 */ 394 void 395 m_move_pkthdr(struct mbuf *to, struct mbuf *from) 396 { 397 398 #if 0 399 /* see below for why these are not enabled */ 400 M_ASSERTPKTHDR(to); 401 /* Note: with MAC, this may not be a good assertion. */ 402 KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), 403 ("m_move_pkthdr: to has tags")); 404 #endif 405 #ifdef MAC 406 /* 407 * XXXMAC: It could be this should also occur for non-MAC? 408 */ 409 if (to->m_flags & M_PKTHDR) 410 m_tag_delete_chain(to, NULL); 411 #endif 412 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT); 413 if ((to->m_flags & M_EXT) == 0) 414 to->m_data = to->m_pktdat; 415 to->m_pkthdr = from->m_pkthdr; /* especially tags */ 416 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */ 417 from->m_flags &= ~M_PKTHDR; 418 } 419 420 /* 421 * Duplicate "from"'s mbuf pkthdr in "to". 422 * "from" must have M_PKTHDR set, and "to" must be empty. 423 * In particular, this does a deep copy of the packet tags. 424 */ 425 int 426 m_dup_pkthdr(struct mbuf *to, struct mbuf *from, int how) 427 { 428 429 #if 0 430 /* 431 * The mbuf allocator only initializes the pkthdr 432 * when the mbuf is allocated with MGETHDR. Many users 433 * (e.g. m_copy*, m_prepend) use MGET and then 434 * smash the pkthdr as needed causing these 435 * assertions to trip. For now just disable them. 436 */ 437 M_ASSERTPKTHDR(to); 438 /* Note: with MAC, this may not be a good assertion. */ 439 KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_dup_pkthdr: to has tags")); 440 #endif 441 MBUF_CHECKSLEEP(how); 442 #ifdef MAC 443 if (to->m_flags & M_PKTHDR) 444 m_tag_delete_chain(to, NULL); 445 #endif 446 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT); 447 if ((to->m_flags & M_EXT) == 0) 448 to->m_data = to->m_pktdat; 449 to->m_pkthdr = from->m_pkthdr; 450 SLIST_INIT(&to->m_pkthdr.tags); 451 return (m_tag_copy_chain(to, from, MBTOM(how))); 452 } 453 454 /* 455 * Lesser-used path for M_PREPEND: 456 * allocate new mbuf to prepend to chain, 457 * copy junk along. 458 */ 459 struct mbuf * 460 m_prepend(struct mbuf *m, int len, int how) 461 { 462 struct mbuf *mn; 463 464 if (m->m_flags & M_PKTHDR) 465 MGETHDR(mn, how, m->m_type); 466 else 467 MGET(mn, how, m->m_type); 468 if (mn == NULL) { 469 m_freem(m); 470 return (NULL); 471 } 472 if (m->m_flags & M_PKTHDR) 473 M_MOVE_PKTHDR(mn, m); 474 mn->m_next = m; 475 m = mn; 476 if (len < MHLEN) 477 MH_ALIGN(m, len); 478 m->m_len = len; 479 return (m); 480 } 481 482 /* 483 * Make a copy of an mbuf chain starting "off0" bytes from the beginning, 484 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf. 485 * The wait parameter is a choice of M_TRYWAIT/M_DONTWAIT from caller. 486 * Note that the copy is read-only, because clusters are not copied, 487 * only their reference counts are incremented. 488 */ 489 struct mbuf * 490 m_copym(struct mbuf *m, int off0, int len, int wait) 491 { 492 struct mbuf *n, **np; 493 int off = off0; 494 struct mbuf *top; 495 int copyhdr = 0; 496 497 KASSERT(off >= 0, ("m_copym, negative off %d", off)); 498 KASSERT(len >= 0, ("m_copym, negative len %d", len)); 499 MBUF_CHECKSLEEP(wait); 500 if (off == 0 && m->m_flags & M_PKTHDR) 501 copyhdr = 1; 502 while (off > 0) { 503 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain")); 504 if (off < m->m_len) 505 break; 506 off -= m->m_len; 507 m = m->m_next; 508 } 509 np = ⊤ 510 top = 0; 511 while (len > 0) { 512 if (m == NULL) { 513 KASSERT(len == M_COPYALL, 514 ("m_copym, length > size of mbuf chain")); 515 break; 516 } 517 if (copyhdr) 518 MGETHDR(n, wait, m->m_type); 519 else 520 MGET(n, wait, m->m_type); 521 *np = n; 522 if (n == NULL) 523 goto nospace; 524 if (copyhdr) { 525 if (!m_dup_pkthdr(n, m, wait)) 526 goto nospace; 527 if (len == M_COPYALL) 528 n->m_pkthdr.len -= off0; 529 else 530 n->m_pkthdr.len = len; 531 copyhdr = 0; 532 } 533 n->m_len = min(len, m->m_len - off); 534 if (m->m_flags & M_EXT) { 535 n->m_data = m->m_data + off; 536 n->m_ext = m->m_ext; 537 n->m_flags |= M_EXT; 538 MEXT_ADD_REF(m); 539 n->m_ext.ref_cnt = m->m_ext.ref_cnt; 540 } else 541 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t), 542 (u_int)n->m_len); 543 if (len != M_COPYALL) 544 len -= n->m_len; 545 off = 0; 546 m = m->m_next; 547 np = &n->m_next; 548 } 549 if (top == NULL) 550 mbstat.m_mcfail++; /* XXX: No consistency. */ 551 552 return (top); 553 nospace: 554 m_freem(top); 555 mbstat.m_mcfail++; /* XXX: No consistency. */ 556 return (NULL); 557 } 558 559 /* 560 * Returns mbuf chain with new head for the prepending case. 561 * Copies from mbuf (chain) n from off for len to mbuf (chain) m 562 * either prepending or appending the data. 563 * The resulting mbuf (chain) m is fully writeable. 564 * m is destination (is made writeable) 565 * n is source, off is offset in source, len is len from offset 566 * dir, 0 append, 1 prepend 567 * how, wait or nowait 568 */ 569 570 static int 571 m_bcopyxxx(void *s, void *t, u_int len) 572 { 573 bcopy(s, t, (size_t)len); 574 return 0; 575 } 576 577 struct mbuf * 578 m_copymdata(struct mbuf *m, struct mbuf *n, int off, int len, 579 int prep, int how) 580 { 581 struct mbuf *mm, *x, *z; 582 caddr_t p; 583 int i, mlen, nlen = 0; 584 caddr_t buf[MLEN]; 585 586 KASSERT(m != NULL && n != NULL, ("m_copymdata, no target or source")); 587 KASSERT(off >= 0, ("m_copymdata, negative off %d", off)); 588 KASSERT(len >= 0, ("m_copymdata, negative len %d", len)); 589 KASSERT(prep == 0 || prep == 1, ("m_copymdata, unknown direction %d", prep)); 590 591 /* Make sure environment is sane. */ 592 for (z = m; z != NULL; z = z->m_next) { 593 mlen += z->m_len; 594 if (!M_WRITABLE(z)) { 595 /* Make clusters writeable. */ 596 if (z->m_flags & M_RDONLY) 597 return NULL; /* Can't handle ext ref. */ 598 x = m_getcl(how, MT_DATA, 0); 599 if (!x) 600 return NULL; 601 bcopy(z->m_ext.ext_buf, x->m_ext.ext_buf, x->m_ext.ext_size); 602 p = x->m_ext.ext_buf + (z->m_data - z->m_ext.ext_buf); 603 MEXT_REM_REF(z); /* XXX */ 604 z->m_data = p; 605 x->m_flags &= ~M_EXT; 606 (void)m_free(x); 607 } 608 } 609 mm = prep ? m : z; 610 for (z = n; z != NULL; z = z->m_next) 611 nlen += z->m_len; 612 if (len == M_COPYALL) 613 len = nlen - off; 614 if (off + len > nlen || len < 1) 615 return NULL; 616 617 /* 618 * Append/prepend the data. Allocating mbufs as necessary. 619 */ 620 /* Shortcut if enough free space in first/last mbuf. */ 621 if (!prep && M_TRAILINGSPACE(mm) >= len) { 622 m_apply(n, off, len, m_bcopyxxx, mtod(mm, caddr_t) + 623 mm->m_len); 624 mm->m_len += len; 625 mm->m_pkthdr.len += len; 626 return m; 627 } 628 if (prep && M_LEADINGSPACE(mm) >= len) { 629 mm->m_data = mtod(mm, caddr_t) - len; 630 m_apply(n, off, len, m_bcopyxxx, mtod(mm, caddr_t)); 631 mm->m_len += len; 632 mm->m_pkthdr.len += len; 633 return mm; 634 } 635 636 /* Expand first/last mbuf to cluster if possible. */ 637 if (!prep && !(mm->m_flags & M_EXT) && len > M_TRAILINGSPACE(mm)) { 638 bcopy(mm->m_data, &buf, mm->m_len); 639 m_clget(mm, how); 640 if (!(mm->m_flags & M_EXT)) 641 return NULL; 642 bcopy(&buf, mm->m_ext.ext_buf, mm->m_len); 643 mm->m_data = mm->m_ext.ext_buf; 644 mm->m_pkthdr.header = NULL; 645 } 646 if (prep && !(mm->m_flags & M_EXT) && len > M_LEADINGSPACE(mm)) { 647 bcopy(mm->m_data, &buf, mm->m_len); 648 m_clget(mm, how); 649 if (!(mm->m_flags & M_EXT)) 650 return NULL; 651 bcopy(&buf, (caddr_t *)mm->m_ext.ext_buf + 652 mm->m_ext.ext_size - mm->m_len, mm->m_len); 653 mm->m_data = (caddr_t)mm->m_ext.ext_buf + 654 mm->m_ext.ext_size - mm->m_len; 655 mm->m_pkthdr.header = NULL; 656 } 657 658 /* Append/prepend as many mbuf (clusters) as necessary to fit len. */ 659 if (!prep && len > M_TRAILINGSPACE(mm)) { 660 if (!m_getm(mm, len - M_TRAILINGSPACE(mm), how, MT_DATA)) 661 return NULL; 662 } 663 if (prep && len > M_LEADINGSPACE(mm)) { 664 if (!(z = m_getm(NULL, len - M_LEADINGSPACE(mm), how, MT_DATA))) 665 return NULL; 666 i = 0; 667 for (x = z; x != NULL; x = x->m_next) { 668 i += x->m_flags & M_EXT ? x->m_ext.ext_size : 669 (x->m_flags & M_PKTHDR ? MHLEN : MLEN); 670 if (!x->m_next) 671 break; 672 } 673 z->m_data += i - len; 674 m_move_pkthdr(mm, z); 675 x->m_next = mm; 676 mm = z; 677 } 678 679 /* Seek to start position in source mbuf. Optimization for long chains. */ 680 while (off > 0) { 681 if (off < n->m_len) 682 break; 683 off -= n->m_len; 684 n = n->m_next; 685 } 686 687 /* Copy data into target mbuf. */ 688 z = mm; 689 while (len > 0) { 690 KASSERT(z != NULL, ("m_copymdata, falling off target edge")); 691 i = M_TRAILINGSPACE(z); 692 m_apply(n, off, i, m_bcopyxxx, mtod(z, caddr_t) + z->m_len); 693 z->m_len += i; 694 /* fixup pkthdr.len if necessary */ 695 if ((prep ? mm : m)->m_flags & M_PKTHDR) 696 (prep ? mm : m)->m_pkthdr.len += i; 697 off += i; 698 len -= i; 699 z = z->m_next; 700 } 701 return (prep ? mm : m); 702 } 703 704 /* 705 * Copy an entire packet, including header (which must be present). 706 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'. 707 * Note that the copy is read-only, because clusters are not copied, 708 * only their reference counts are incremented. 709 * Preserve alignment of the first mbuf so if the creator has left 710 * some room at the beginning (e.g. for inserting protocol headers) 711 * the copies still have the room available. 712 */ 713 struct mbuf * 714 m_copypacket(struct mbuf *m, int how) 715 { 716 struct mbuf *top, *n, *o; 717 718 MBUF_CHECKSLEEP(how); 719 MGET(n, how, m->m_type); 720 top = n; 721 if (n == NULL) 722 goto nospace; 723 724 if (!m_dup_pkthdr(n, m, how)) 725 goto nospace; 726 n->m_len = m->m_len; 727 if (m->m_flags & M_EXT) { 728 n->m_data = m->m_data; 729 n->m_ext = m->m_ext; 730 n->m_flags |= M_EXT; 731 MEXT_ADD_REF(m); 732 n->m_ext.ref_cnt = m->m_ext.ref_cnt; 733 } else { 734 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat ); 735 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 736 } 737 738 m = m->m_next; 739 while (m) { 740 MGET(o, how, m->m_type); 741 if (o == NULL) 742 goto nospace; 743 744 n->m_next = o; 745 n = n->m_next; 746 747 n->m_len = m->m_len; 748 if (m->m_flags & M_EXT) { 749 n->m_data = m->m_data; 750 n->m_ext = m->m_ext; 751 n->m_flags |= M_EXT; 752 MEXT_ADD_REF(m); 753 n->m_ext.ref_cnt = m->m_ext.ref_cnt; 754 } else { 755 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 756 } 757 758 m = m->m_next; 759 } 760 return top; 761 nospace: 762 m_freem(top); 763 mbstat.m_mcfail++; /* XXX: No consistency. */ 764 return (NULL); 765 } 766 767 /* 768 * Copy data from an mbuf chain starting "off" bytes from the beginning, 769 * continuing for "len" bytes, into the indicated buffer. 770 */ 771 void 772 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp) 773 { 774 u_int count; 775 776 KASSERT(off >= 0, ("m_copydata, negative off %d", off)); 777 KASSERT(len >= 0, ("m_copydata, negative len %d", len)); 778 while (off > 0) { 779 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain")); 780 if (off < m->m_len) 781 break; 782 off -= m->m_len; 783 m = m->m_next; 784 } 785 while (len > 0) { 786 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain")); 787 count = min(m->m_len - off, len); 788 bcopy(mtod(m, caddr_t) + off, cp, count); 789 len -= count; 790 cp += count; 791 off = 0; 792 m = m->m_next; 793 } 794 } 795 796 /* 797 * Copy a packet header mbuf chain into a completely new chain, including 798 * copying any mbuf clusters. Use this instead of m_copypacket() when 799 * you need a writable copy of an mbuf chain. 800 */ 801 struct mbuf * 802 m_dup(struct mbuf *m, int how) 803 { 804 struct mbuf **p, *top = NULL; 805 int remain, moff, nsize; 806 807 MBUF_CHECKSLEEP(how); 808 /* Sanity check */ 809 if (m == NULL) 810 return (NULL); 811 M_ASSERTPKTHDR(m); 812 813 /* While there's more data, get a new mbuf, tack it on, and fill it */ 814 remain = m->m_pkthdr.len; 815 moff = 0; 816 p = ⊤ 817 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */ 818 struct mbuf *n; 819 820 /* Get the next new mbuf */ 821 if (remain >= MINCLSIZE) { 822 n = m_getcl(how, m->m_type, 0); 823 nsize = MCLBYTES; 824 } else { 825 n = m_get(how, m->m_type); 826 nsize = MLEN; 827 } 828 if (n == NULL) 829 goto nospace; 830 831 if (top == NULL) { /* First one, must be PKTHDR */ 832 if (!m_dup_pkthdr(n, m, how)) { 833 m_free(n); 834 goto nospace; 835 } 836 nsize = MHLEN; 837 } 838 n->m_len = 0; 839 840 /* Link it into the new chain */ 841 *p = n; 842 p = &n->m_next; 843 844 /* Copy data from original mbuf(s) into new mbuf */ 845 while (n->m_len < nsize && m != NULL) { 846 int chunk = min(nsize - n->m_len, m->m_len - moff); 847 848 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk); 849 moff += chunk; 850 n->m_len += chunk; 851 remain -= chunk; 852 if (moff == m->m_len) { 853 m = m->m_next; 854 moff = 0; 855 } 856 } 857 858 /* Check correct total mbuf length */ 859 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL), 860 ("%s: bogus m_pkthdr.len", __func__)); 861 } 862 return (top); 863 864 nospace: 865 m_freem(top); 866 mbstat.m_mcfail++; /* XXX: No consistency. */ 867 return (NULL); 868 } 869 870 /* 871 * Concatenate mbuf chain n to m. 872 * Both chains must be of the same type (e.g. MT_DATA). 873 * Any m_pkthdr is not updated. 874 */ 875 void 876 m_cat(struct mbuf *m, struct mbuf *n) 877 { 878 while (m->m_next) 879 m = m->m_next; 880 while (n) { 881 if (m->m_flags & M_EXT || 882 m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) { 883 /* just join the two chains */ 884 m->m_next = n; 885 return; 886 } 887 /* splat the data from one into the other */ 888 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 889 (u_int)n->m_len); 890 m->m_len += n->m_len; 891 n = m_free(n); 892 } 893 } 894 895 void 896 m_adj(struct mbuf *mp, int req_len) 897 { 898 int len = req_len; 899 struct mbuf *m; 900 int count; 901 902 if ((m = mp) == NULL) 903 return; 904 if (len >= 0) { 905 /* 906 * Trim from head. 907 */ 908 while (m != NULL && len > 0) { 909 if (m->m_len <= len) { 910 len -= m->m_len; 911 m->m_len = 0; 912 m = m->m_next; 913 } else { 914 m->m_len -= len; 915 m->m_data += len; 916 len = 0; 917 } 918 } 919 m = mp; 920 if (mp->m_flags & M_PKTHDR) 921 m->m_pkthdr.len -= (req_len - len); 922 } else { 923 /* 924 * Trim from tail. Scan the mbuf chain, 925 * calculating its length and finding the last mbuf. 926 * If the adjustment only affects this mbuf, then just 927 * adjust and return. Otherwise, rescan and truncate 928 * after the remaining size. 929 */ 930 len = -len; 931 count = 0; 932 for (;;) { 933 count += m->m_len; 934 if (m->m_next == (struct mbuf *)0) 935 break; 936 m = m->m_next; 937 } 938 if (m->m_len >= len) { 939 m->m_len -= len; 940 if (mp->m_flags & M_PKTHDR) 941 mp->m_pkthdr.len -= len; 942 return; 943 } 944 count -= len; 945 if (count < 0) 946 count = 0; 947 /* 948 * Correct length for chain is "count". 949 * Find the mbuf with last data, adjust its length, 950 * and toss data from remaining mbufs on chain. 951 */ 952 m = mp; 953 if (m->m_flags & M_PKTHDR) 954 m->m_pkthdr.len = count; 955 for (; m; m = m->m_next) { 956 if (m->m_len >= count) { 957 m->m_len = count; 958 if (m->m_next != NULL) { 959 m_freem(m->m_next); 960 m->m_next = NULL; 961 } 962 break; 963 } 964 count -= m->m_len; 965 } 966 } 967 } 968 969 /* 970 * Rearange an mbuf chain so that len bytes are contiguous 971 * and in the data area of an mbuf (so that mtod and dtom 972 * will work for a structure of size len). Returns the resulting 973 * mbuf chain on success, frees it and returns null on failure. 974 * If there is room, it will add up to max_protohdr-len extra bytes to the 975 * contiguous region in an attempt to avoid being called next time. 976 */ 977 struct mbuf * 978 m_pullup(struct mbuf *n, int len) 979 { 980 struct mbuf *m; 981 int count; 982 int space; 983 984 /* 985 * If first mbuf has no cluster, and has room for len bytes 986 * without shifting current data, pullup into it, 987 * otherwise allocate a new mbuf to prepend to the chain. 988 */ 989 if ((n->m_flags & M_EXT) == 0 && 990 n->m_data + len < &n->m_dat[MLEN] && n->m_next) { 991 if (n->m_len >= len) 992 return (n); 993 m = n; 994 n = n->m_next; 995 len -= m->m_len; 996 } else { 997 if (len > MHLEN) 998 goto bad; 999 MGET(m, M_DONTWAIT, n->m_type); 1000 if (m == NULL) 1001 goto bad; 1002 m->m_len = 0; 1003 if (n->m_flags & M_PKTHDR) 1004 M_MOVE_PKTHDR(m, n); 1005 } 1006 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 1007 do { 1008 count = min(min(max(len, max_protohdr), space), n->m_len); 1009 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 1010 (u_int)count); 1011 len -= count; 1012 m->m_len += count; 1013 n->m_len -= count; 1014 space -= count; 1015 if (n->m_len) 1016 n->m_data += count; 1017 else 1018 n = m_free(n); 1019 } while (len > 0 && n); 1020 if (len > 0) { 1021 (void) m_free(m); 1022 goto bad; 1023 } 1024 m->m_next = n; 1025 return (m); 1026 bad: 1027 m_freem(n); 1028 mbstat.m_mpfail++; /* XXX: No consistency. */ 1029 return (NULL); 1030 } 1031 1032 /* 1033 * Like m_pullup(), except a new mbuf is always allocated, and we allow 1034 * the amount of empty space before the data in the new mbuf to be specified 1035 * (in the event that the caller expects to prepend later). 1036 */ 1037 int MSFail; 1038 1039 struct mbuf * 1040 m_copyup(struct mbuf *n, int len, int dstoff) 1041 { 1042 struct mbuf *m; 1043 int count, space; 1044 1045 if (len > (MHLEN - dstoff)) 1046 goto bad; 1047 MGET(m, M_DONTWAIT, n->m_type); 1048 if (m == NULL) 1049 goto bad; 1050 m->m_len = 0; 1051 if (n->m_flags & M_PKTHDR) 1052 M_MOVE_PKTHDR(m, n); 1053 m->m_data += dstoff; 1054 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 1055 do { 1056 count = min(min(max(len, max_protohdr), space), n->m_len); 1057 memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t), 1058 (unsigned)count); 1059 len -= count; 1060 m->m_len += count; 1061 n->m_len -= count; 1062 space -= count; 1063 if (n->m_len) 1064 n->m_data += count; 1065 else 1066 n = m_free(n); 1067 } while (len > 0 && n); 1068 if (len > 0) { 1069 (void) m_free(m); 1070 goto bad; 1071 } 1072 m->m_next = n; 1073 return (m); 1074 bad: 1075 m_freem(n); 1076 MSFail++; 1077 return (NULL); 1078 } 1079 1080 /* 1081 * Partition an mbuf chain in two pieces, returning the tail -- 1082 * all but the first len0 bytes. In case of failure, it returns NULL and 1083 * attempts to restore the chain to its original state. 1084 * 1085 * Note that the resulting mbufs might be read-only, because the new 1086 * mbuf can end up sharing an mbuf cluster with the original mbuf if 1087 * the "breaking point" happens to lie within a cluster mbuf. Use the 1088 * M_WRITABLE() macro to check for this case. 1089 */ 1090 struct mbuf * 1091 m_split(struct mbuf *m0, int len0, int wait) 1092 { 1093 struct mbuf *m, *n; 1094 u_int len = len0, remain; 1095 1096 MBUF_CHECKSLEEP(wait); 1097 for (m = m0; m && len > m->m_len; m = m->m_next) 1098 len -= m->m_len; 1099 if (m == NULL) 1100 return (NULL); 1101 remain = m->m_len - len; 1102 if (m0->m_flags & M_PKTHDR) { 1103 MGETHDR(n, wait, m0->m_type); 1104 if (n == NULL) 1105 return (NULL); 1106 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; 1107 n->m_pkthdr.len = m0->m_pkthdr.len - len0; 1108 m0->m_pkthdr.len = len0; 1109 if (m->m_flags & M_EXT) 1110 goto extpacket; 1111 if (remain > MHLEN) { 1112 /* m can't be the lead packet */ 1113 MH_ALIGN(n, 0); 1114 n->m_next = m_split(m, len, wait); 1115 if (n->m_next == NULL) { 1116 (void) m_free(n); 1117 return (NULL); 1118 } else { 1119 n->m_len = 0; 1120 return (n); 1121 } 1122 } else 1123 MH_ALIGN(n, remain); 1124 } else if (remain == 0) { 1125 n = m->m_next; 1126 m->m_next = NULL; 1127 return (n); 1128 } else { 1129 MGET(n, wait, m->m_type); 1130 if (n == NULL) 1131 return (NULL); 1132 M_ALIGN(n, remain); 1133 } 1134 extpacket: 1135 if (m->m_flags & M_EXT) { 1136 n->m_flags |= M_EXT; 1137 n->m_ext = m->m_ext; 1138 MEXT_ADD_REF(m); 1139 n->m_ext.ref_cnt = m->m_ext.ref_cnt; 1140 n->m_data = m->m_data + len; 1141 } else { 1142 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain); 1143 } 1144 n->m_len = remain; 1145 m->m_len = len; 1146 n->m_next = m->m_next; 1147 m->m_next = NULL; 1148 return (n); 1149 } 1150 /* 1151 * Routine to copy from device local memory into mbufs. 1152 * Note that `off' argument is offset into first mbuf of target chain from 1153 * which to begin copying the data to. 1154 */ 1155 struct mbuf * 1156 m_devget(char *buf, int totlen, int off, struct ifnet *ifp, 1157 void (*copy)(char *from, caddr_t to, u_int len)) 1158 { 1159 struct mbuf *m; 1160 struct mbuf *top = NULL, **mp = ⊤ 1161 int len; 1162 1163 if (off < 0 || off > MHLEN) 1164 return (NULL); 1165 1166 while (totlen > 0) { 1167 if (top == NULL) { /* First one, must be PKTHDR */ 1168 if (totlen + off >= MINCLSIZE) { 1169 m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR); 1170 len = MCLBYTES; 1171 } else { 1172 m = m_gethdr(M_DONTWAIT, MT_DATA); 1173 len = MHLEN; 1174 1175 /* Place initial small packet/header at end of mbuf */ 1176 if (m && totlen + off + max_linkhdr <= MLEN) { 1177 m->m_data += max_linkhdr; 1178 len -= max_linkhdr; 1179 } 1180 } 1181 if (m == NULL) 1182 return NULL; 1183 m->m_pkthdr.rcvif = ifp; 1184 m->m_pkthdr.len = totlen; 1185 } else { 1186 if (totlen + off >= MINCLSIZE) { 1187 m = m_getcl(M_DONTWAIT, MT_DATA, 0); 1188 len = MCLBYTES; 1189 } else { 1190 m = m_get(M_DONTWAIT, MT_DATA); 1191 len = MLEN; 1192 } 1193 if (m == NULL) { 1194 m_freem(top); 1195 return NULL; 1196 } 1197 } 1198 if (off) { 1199 m->m_data += off; 1200 len -= off; 1201 off = 0; 1202 } 1203 m->m_len = len = min(totlen, len); 1204 if (copy) 1205 copy(buf, mtod(m, caddr_t), (u_int)len); 1206 else 1207 bcopy(buf, mtod(m, caddr_t), (u_int)len); 1208 buf += len; 1209 *mp = m; 1210 mp = &m->m_next; 1211 totlen -= len; 1212 } 1213 return (top); 1214 } 1215 1216 /* 1217 * Copy data from a buffer back into the indicated mbuf chain, 1218 * starting "off" bytes from the beginning, extending the mbuf 1219 * chain if necessary. 1220 */ 1221 void 1222 m_copyback(struct mbuf *m0, int off, int len, c_caddr_t cp) 1223 { 1224 int mlen; 1225 struct mbuf *m = m0, *n; 1226 int totlen = 0; 1227 1228 if (m0 == NULL) 1229 return; 1230 while (off > (mlen = m->m_len)) { 1231 off -= mlen; 1232 totlen += mlen; 1233 if (m->m_next == NULL) { 1234 n = m_get(M_DONTWAIT, m->m_type); 1235 if (n == NULL) 1236 goto out; 1237 bzero(mtod(n, caddr_t), MLEN); 1238 n->m_len = min(MLEN, len + off); 1239 m->m_next = n; 1240 } 1241 m = m->m_next; 1242 } 1243 while (len > 0) { 1244 mlen = min (m->m_len - off, len); 1245 bcopy(cp, off + mtod(m, caddr_t), (u_int)mlen); 1246 cp += mlen; 1247 len -= mlen; 1248 mlen += off; 1249 off = 0; 1250 totlen += mlen; 1251 if (len == 0) 1252 break; 1253 if (m->m_next == NULL) { 1254 n = m_get(M_DONTWAIT, m->m_type); 1255 if (n == NULL) 1256 break; 1257 n->m_len = min(MLEN, len); 1258 m->m_next = n; 1259 } 1260 m = m->m_next; 1261 } 1262 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) 1263 m->m_pkthdr.len = totlen; 1264 } 1265 1266 /* 1267 * Append the specified data to the indicated mbuf chain, 1268 * Extend the mbuf chain if the new data does not fit in 1269 * existing space. 1270 * 1271 * Return 1 if able to complete the job; otherwise 0. 1272 */ 1273 int 1274 m_append(struct mbuf *m0, int len, c_caddr_t cp) 1275 { 1276 struct mbuf *m, *n; 1277 int remainder, space; 1278 1279 for (m = m0; m->m_next != NULL; m = m->m_next) 1280 ; 1281 remainder = len; 1282 space = M_TRAILINGSPACE(m); 1283 if (space > 0) { 1284 /* 1285 * Copy into available space. 1286 */ 1287 if (space > remainder) 1288 space = remainder; 1289 bcopy(cp, mtod(m, caddr_t) + m->m_len, space); 1290 m->m_len += space; 1291 cp += space, remainder -= space; 1292 } 1293 while (remainder > 0) { 1294 /* 1295 * Allocate a new mbuf; could check space 1296 * and allocate a cluster instead. 1297 */ 1298 n = m_get(M_DONTWAIT, m->m_type); 1299 if (n == NULL) 1300 break; 1301 n->m_len = min(MLEN, remainder); 1302 bcopy(cp, mtod(n, caddr_t), n->m_len); 1303 cp += n->m_len, remainder -= n->m_len; 1304 m->m_next = n; 1305 m = n; 1306 } 1307 if (m0->m_flags & M_PKTHDR) 1308 m0->m_pkthdr.len += len - remainder; 1309 return (remainder == 0); 1310 } 1311 1312 /* 1313 * Apply function f to the data in an mbuf chain starting "off" bytes from 1314 * the beginning, continuing for "len" bytes. 1315 */ 1316 int 1317 m_apply(struct mbuf *m, int off, int len, 1318 int (*f)(void *, void *, u_int), void *arg) 1319 { 1320 u_int count; 1321 int rval; 1322 1323 KASSERT(off >= 0, ("m_apply, negative off %d", off)); 1324 KASSERT(len >= 0, ("m_apply, negative len %d", len)); 1325 while (off > 0) { 1326 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain")); 1327 if (off < m->m_len) 1328 break; 1329 off -= m->m_len; 1330 m = m->m_next; 1331 } 1332 while (len > 0) { 1333 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain")); 1334 count = min(m->m_len - off, len); 1335 rval = (*f)(arg, mtod(m, caddr_t) + off, count); 1336 if (rval) 1337 return (rval); 1338 len -= count; 1339 off = 0; 1340 m = m->m_next; 1341 } 1342 return (0); 1343 } 1344 1345 /* 1346 * Return a pointer to mbuf/offset of location in mbuf chain. 1347 */ 1348 struct mbuf * 1349 m_getptr(struct mbuf *m, int loc, int *off) 1350 { 1351 1352 while (loc >= 0) { 1353 /* Normal end of search. */ 1354 if (m->m_len > loc) { 1355 *off = loc; 1356 return (m); 1357 } else { 1358 loc -= m->m_len; 1359 if (m->m_next == NULL) { 1360 if (loc == 0) { 1361 /* Point at the end of valid data. */ 1362 *off = m->m_len; 1363 return (m); 1364 } 1365 return (NULL); 1366 } 1367 m = m->m_next; 1368 } 1369 } 1370 return (NULL); 1371 } 1372 1373 void 1374 m_print(const struct mbuf *m, int maxlen) 1375 { 1376 int len; 1377 int pdata; 1378 const struct mbuf *m2; 1379 1380 if (m->m_flags & M_PKTHDR) 1381 len = m->m_pkthdr.len; 1382 else 1383 len = -1; 1384 m2 = m; 1385 while (m2 != NULL && (len == -1 || len)) { 1386 pdata = m2->m_len; 1387 if (maxlen != -1 && pdata > maxlen) 1388 pdata = maxlen; 1389 printf("mbuf: %p len: %d, next: %p, %b%s", m2, m2->m_len, 1390 m2->m_next, m2->m_flags, "\20\20freelist\17skipfw" 1391 "\11proto5\10proto4\7proto3\6proto2\5proto1\4rdonly" 1392 "\3eor\2pkthdr\1ext", pdata ? "" : "\n"); 1393 if (pdata) 1394 printf(", %*D\n", m2->m_len, (u_char *)m2->m_data, "-"); 1395 if (len != -1) 1396 len -= m2->m_len; 1397 m2 = m2->m_next; 1398 } 1399 if (len > 0) 1400 printf("%d bytes unaccounted for.\n", len); 1401 return; 1402 } 1403 1404 u_int 1405 m_fixhdr(struct mbuf *m0) 1406 { 1407 u_int len; 1408 1409 len = m_length(m0, NULL); 1410 m0->m_pkthdr.len = len; 1411 return (len); 1412 } 1413 1414 u_int 1415 m_length(struct mbuf *m0, struct mbuf **last) 1416 { 1417 struct mbuf *m; 1418 u_int len; 1419 1420 len = 0; 1421 for (m = m0; m != NULL; m = m->m_next) { 1422 len += m->m_len; 1423 if (m->m_next == NULL) 1424 break; 1425 } 1426 if (last != NULL) 1427 *last = m; 1428 return (len); 1429 } 1430 1431 /* 1432 * Defragment a mbuf chain, returning the shortest possible 1433 * chain of mbufs and clusters. If allocation fails and 1434 * this cannot be completed, NULL will be returned, but 1435 * the passed in chain will be unchanged. Upon success, 1436 * the original chain will be freed, and the new chain 1437 * will be returned. 1438 * 1439 * If a non-packet header is passed in, the original 1440 * mbuf (chain?) will be returned unharmed. 1441 */ 1442 struct mbuf * 1443 m_defrag(struct mbuf *m0, int how) 1444 { 1445 struct mbuf *m_new = NULL, *m_final = NULL; 1446 int progress = 0, length; 1447 1448 MBUF_CHECKSLEEP(how); 1449 if (!(m0->m_flags & M_PKTHDR)) 1450 return (m0); 1451 1452 m_fixhdr(m0); /* Needed sanity check */ 1453 1454 #ifdef MBUF_STRESS_TEST 1455 if (m_defragrandomfailures) { 1456 int temp = arc4random() & 0xff; 1457 if (temp == 0xba) 1458 goto nospace; 1459 } 1460 #endif 1461 1462 if (m0->m_pkthdr.len > MHLEN) 1463 m_final = m_getcl(how, MT_DATA, M_PKTHDR); 1464 else 1465 m_final = m_gethdr(how, MT_DATA); 1466 1467 if (m_final == NULL) 1468 goto nospace; 1469 1470 if (m_dup_pkthdr(m_final, m0, how) == 0) 1471 goto nospace; 1472 1473 m_new = m_final; 1474 1475 while (progress < m0->m_pkthdr.len) { 1476 length = m0->m_pkthdr.len - progress; 1477 if (length > MCLBYTES) 1478 length = MCLBYTES; 1479 1480 if (m_new == NULL) { 1481 if (length > MLEN) 1482 m_new = m_getcl(how, MT_DATA, 0); 1483 else 1484 m_new = m_get(how, MT_DATA); 1485 if (m_new == NULL) 1486 goto nospace; 1487 } 1488 1489 m_copydata(m0, progress, length, mtod(m_new, caddr_t)); 1490 progress += length; 1491 m_new->m_len = length; 1492 if (m_new != m_final) 1493 m_cat(m_final, m_new); 1494 m_new = NULL; 1495 } 1496 #ifdef MBUF_STRESS_TEST 1497 if (m0->m_next == NULL) 1498 m_defraguseless++; 1499 #endif 1500 m_freem(m0); 1501 m0 = m_final; 1502 #ifdef MBUF_STRESS_TEST 1503 m_defragpackets++; 1504 m_defragbytes += m0->m_pkthdr.len; 1505 #endif 1506 return (m0); 1507 nospace: 1508 #ifdef MBUF_STRESS_TEST 1509 m_defragfailure++; 1510 #endif 1511 if (m_final) 1512 m_freem(m_final); 1513 return (NULL); 1514 } 1515 1516 #ifdef MBUF_STRESS_TEST 1517 1518 /* 1519 * Fragment an mbuf chain. There's no reason you'd ever want to do 1520 * this in normal usage, but it's great for stress testing various 1521 * mbuf consumers. 1522 * 1523 * If fragmentation is not possible, the original chain will be 1524 * returned. 1525 * 1526 * Possible length values: 1527 * 0 no fragmentation will occur 1528 * > 0 each fragment will be of the specified length 1529 * -1 each fragment will be the same random value in length 1530 * -2 each fragment's length will be entirely random 1531 * (Random values range from 1 to 256) 1532 */ 1533 struct mbuf * 1534 m_fragment(struct mbuf *m0, int how, int length) 1535 { 1536 struct mbuf *m_new = NULL, *m_final = NULL; 1537 int progress = 0; 1538 1539 if (!(m0->m_flags & M_PKTHDR)) 1540 return (m0); 1541 1542 if ((length == 0) || (length < -2)) 1543 return (m0); 1544 1545 m_fixhdr(m0); /* Needed sanity check */ 1546 1547 m_final = m_getcl(how, MT_DATA, M_PKTHDR); 1548 1549 if (m_final == NULL) 1550 goto nospace; 1551 1552 if (m_dup_pkthdr(m_final, m0, how) == 0) 1553 goto nospace; 1554 1555 m_new = m_final; 1556 1557 if (length == -1) 1558 length = 1 + (arc4random() & 255); 1559 1560 while (progress < m0->m_pkthdr.len) { 1561 int fraglen; 1562 1563 if (length > 0) 1564 fraglen = length; 1565 else 1566 fraglen = 1 + (arc4random() & 255); 1567 if (fraglen > m0->m_pkthdr.len - progress) 1568 fraglen = m0->m_pkthdr.len - progress; 1569 1570 if (fraglen > MCLBYTES) 1571 fraglen = MCLBYTES; 1572 1573 if (m_new == NULL) { 1574 m_new = m_getcl(how, MT_DATA, 0); 1575 if (m_new == NULL) 1576 goto nospace; 1577 } 1578 1579 m_copydata(m0, progress, fraglen, mtod(m_new, caddr_t)); 1580 progress += fraglen; 1581 m_new->m_len = fraglen; 1582 if (m_new != m_final) 1583 m_cat(m_final, m_new); 1584 m_new = NULL; 1585 } 1586 m_freem(m0); 1587 m0 = m_final; 1588 return (m0); 1589 nospace: 1590 if (m_final) 1591 m_freem(m_final); 1592 /* Return the original chain on failure */ 1593 return (m0); 1594 } 1595 1596 #endif 1597 1598 struct mbuf * 1599 m_uiotombuf(struct uio *uio, int how, int len, int align) 1600 { 1601 struct mbuf *m_new = NULL, *m_final = NULL; 1602 int progress = 0, error = 0, length, total; 1603 1604 if (len > 0) 1605 total = min(uio->uio_resid, len); 1606 else 1607 total = uio->uio_resid; 1608 if (align >= MHLEN) 1609 goto nospace; 1610 if (total + align > MHLEN) 1611 m_final = m_getcl(how, MT_DATA, M_PKTHDR); 1612 else 1613 m_final = m_gethdr(how, MT_DATA); 1614 if (m_final == NULL) 1615 goto nospace; 1616 m_final->m_data += align; 1617 m_new = m_final; 1618 while (progress < total) { 1619 length = total - progress; 1620 if (length > MCLBYTES) 1621 length = MCLBYTES; 1622 if (m_new == NULL) { 1623 if (length > MLEN) 1624 m_new = m_getcl(how, MT_DATA, 0); 1625 else 1626 m_new = m_get(how, MT_DATA); 1627 if (m_new == NULL) 1628 goto nospace; 1629 } 1630 error = uiomove(mtod(m_new, void *), length, uio); 1631 if (error) 1632 goto nospace; 1633 progress += length; 1634 m_new->m_len = length; 1635 if (m_new != m_final) 1636 m_cat(m_final, m_new); 1637 m_new = NULL; 1638 } 1639 m_fixhdr(m_final); 1640 return (m_final); 1641 nospace: 1642 if (m_new) 1643 m_free(m_new); 1644 if (m_final) 1645 m_freem(m_final); 1646 return (NULL); 1647 } 1648 1649 /* 1650 * Set the m_data pointer of a newly-allocated mbuf 1651 * to place an object of the specified size at the 1652 * end of the mbuf, longword aligned. 1653 */ 1654 void 1655 m_align(struct mbuf *m, int len) 1656 { 1657 int adjust; 1658 1659 if (m->m_flags & M_EXT) 1660 adjust = m->m_ext.ext_size - len; 1661 else if (m->m_flags & M_PKTHDR) 1662 adjust = MHLEN - len; 1663 else 1664 adjust = MLEN - len; 1665 m->m_data += adjust &~ (sizeof(long)-1); 1666 } 1667