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/malloc.h> 45 #include <sys/mbuf.h> 46 #include <sys/sysctl.h> 47 #include <sys/domain.h> 48 #include <sys/protosw.h> 49 #include <sys/uio.h> 50 51 #include <security/mac/mac_framework.h> 52 53 int max_linkhdr; 54 int max_protohdr; 55 int max_hdr; 56 int max_datalen; 57 #ifdef MBUF_STRESS_TEST 58 int m_defragpackets; 59 int m_defragbytes; 60 int m_defraguseless; 61 int m_defragfailure; 62 int m_defragrandomfailures; 63 #endif 64 65 /* 66 * sysctl(8) exported objects 67 */ 68 SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RD, 69 &max_linkhdr, 0, "Size of largest link layer header"); 70 SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RD, 71 &max_protohdr, 0, "Size of largest protocol layer header"); 72 SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RD, 73 &max_hdr, 0, "Size of largest link plus protocol header"); 74 SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RD, 75 &max_datalen, 0, "Minimum space left in mbuf after max_hdr"); 76 #ifdef MBUF_STRESS_TEST 77 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD, 78 &m_defragpackets, 0, ""); 79 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD, 80 &m_defragbytes, 0, ""); 81 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD, 82 &m_defraguseless, 0, ""); 83 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD, 84 &m_defragfailure, 0, ""); 85 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW, 86 &m_defragrandomfailures, 0, ""); 87 #endif 88 89 /* 90 * Allocate a given length worth of mbufs and/or clusters (whatever fits 91 * best) and return a pointer to the top of the allocated chain. If an 92 * existing mbuf chain is provided, then we will append the new chain 93 * to the existing one but still return the top of the newly allocated 94 * chain. 95 */ 96 struct mbuf * 97 m_getm2(struct mbuf *m, int len, int how, short type, int flags) 98 { 99 struct mbuf *mb, *nm = NULL, *mtail = NULL; 100 101 KASSERT(len >= 0, ("%s: len is < 0", __func__)); 102 103 /* Validate flags. */ 104 flags &= (M_PKTHDR | M_EOR); 105 106 /* Packet header mbuf must be first in chain. */ 107 if ((flags & M_PKTHDR) && m != NULL) 108 flags &= ~M_PKTHDR; 109 110 /* Loop and append maximum sized mbufs to the chain tail. */ 111 while (len > 0) { 112 if (len > MCLBYTES) 113 mb = m_getjcl(how, type, (flags & M_PKTHDR), 114 MJUMPAGESIZE); 115 else if (len >= MINCLSIZE) 116 mb = m_getcl(how, type, (flags & M_PKTHDR)); 117 else if (flags & M_PKTHDR) 118 mb = m_gethdr(how, type); 119 else 120 mb = m_get(how, type); 121 122 /* Fail the whole operation if one mbuf can't be allocated. */ 123 if (mb == NULL) { 124 if (nm != NULL) 125 m_freem(nm); 126 return (NULL); 127 } 128 129 /* Book keeping. */ 130 len -= (mb->m_flags & M_EXT) ? mb->m_ext.ext_size : 131 ((mb->m_flags & M_PKTHDR) ? MHLEN : MLEN); 132 if (mtail != NULL) 133 mtail->m_next = mb; 134 else 135 nm = mb; 136 mtail = mb; 137 flags &= ~M_PKTHDR; /* Only valid on the first mbuf. */ 138 } 139 if (flags & M_EOR) 140 mtail->m_flags |= M_EOR; /* Only valid on the last mbuf. */ 141 142 /* If mbuf was supplied, append new chain to the end of it. */ 143 if (m != NULL) { 144 for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next) 145 ; 146 mtail->m_next = nm; 147 mtail->m_flags &= ~M_EOR; 148 } else 149 m = nm; 150 151 return (m); 152 } 153 154 /* 155 * Free an entire chain of mbufs and associated external buffers, if 156 * applicable. 157 */ 158 void 159 m_freem(struct mbuf *mb) 160 { 161 162 while (mb != NULL) 163 mb = m_free(mb); 164 } 165 166 /*- 167 * Configure a provided mbuf to refer to the provided external storage 168 * buffer and setup a reference count for said buffer. If the setting 169 * up of the reference count fails, the M_EXT bit will not be set. If 170 * successfull, the M_EXT bit is set in the mbuf's flags. 171 * 172 * Arguments: 173 * mb The existing mbuf to which to attach the provided buffer. 174 * buf The address of the provided external storage buffer. 175 * size The size of the provided buffer. 176 * freef A pointer to a routine that is responsible for freeing the 177 * provided external storage buffer. 178 * args A pointer to an argument structure (of any type) to be passed 179 * to the provided freef routine (may be NULL). 180 * flags Any other flags to be passed to the provided mbuf. 181 * type The type that the external storage buffer should be 182 * labeled with. 183 * 184 * Returns: 185 * Nothing. 186 */ 187 void 188 m_extadd(struct mbuf *mb, caddr_t buf, u_int size, 189 void (*freef)(void *, void *), void *arg1, void *arg2, int flags, int type) 190 { 191 KASSERT(type != EXT_CLUSTER, ("%s: EXT_CLUSTER not allowed", __func__)); 192 193 if (type != EXT_EXTREF) 194 mb->m_ext.ref_cnt = (u_int *)uma_zalloc(zone_ext_refcnt, M_NOWAIT); 195 if (mb->m_ext.ref_cnt != NULL) { 196 *(mb->m_ext.ref_cnt) = 1; 197 mb->m_flags |= (M_EXT | flags); 198 mb->m_ext.ext_buf = buf; 199 mb->m_data = mb->m_ext.ext_buf; 200 mb->m_ext.ext_size = size; 201 mb->m_ext.ext_free = freef; 202 mb->m_ext.ext_arg1 = arg1; 203 mb->m_ext.ext_arg2 = arg2; 204 mb->m_ext.ext_type = type; 205 } 206 } 207 208 /* 209 * Non-directly-exported function to clean up after mbufs with M_EXT 210 * storage attached to them if the reference count hits 1. 211 */ 212 void 213 mb_free_ext(struct mbuf *m) 214 { 215 int skipmbuf; 216 217 KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__)); 218 KASSERT(m->m_ext.ref_cnt != NULL, ("%s: ref_cnt not set", __func__)); 219 220 221 /* 222 * check if the header is embedded in the cluster 223 */ 224 skipmbuf = (m->m_flags & M_NOFREE); 225 226 /* Free attached storage if this mbuf is the only reference to it. */ 227 if (*(m->m_ext.ref_cnt) == 1 || 228 atomic_fetchadd_int(m->m_ext.ref_cnt, -1) == 1) { 229 switch (m->m_ext.ext_type) { 230 case EXT_PACKET: /* The packet zone is special. */ 231 if (*(m->m_ext.ref_cnt) == 0) 232 *(m->m_ext.ref_cnt) = 1; 233 uma_zfree(zone_pack, m); 234 return; /* Job done. */ 235 case EXT_CLUSTER: 236 uma_zfree(zone_clust, m->m_ext.ext_buf); 237 break; 238 case EXT_JUMBOP: 239 uma_zfree(zone_jumbop, m->m_ext.ext_buf); 240 break; 241 case EXT_JUMBO9: 242 uma_zfree(zone_jumbo9, m->m_ext.ext_buf); 243 break; 244 case EXT_JUMBO16: 245 uma_zfree(zone_jumbo16, m->m_ext.ext_buf); 246 break; 247 case EXT_SFBUF: 248 case EXT_NET_DRV: 249 case EXT_MOD_TYPE: 250 case EXT_DISPOSABLE: 251 *(m->m_ext.ref_cnt) = 0; 252 uma_zfree(zone_ext_refcnt, __DEVOLATILE(u_int *, 253 m->m_ext.ref_cnt)); 254 /* FALLTHROUGH */ 255 case EXT_EXTREF: 256 KASSERT(m->m_ext.ext_free != NULL, 257 ("%s: ext_free not set", __func__)); 258 (*(m->m_ext.ext_free))(m->m_ext.ext_arg1, 259 m->m_ext.ext_arg2); 260 break; 261 default: 262 KASSERT(m->m_ext.ext_type == 0, 263 ("%s: unknown ext_type", __func__)); 264 } 265 } 266 if (skipmbuf) 267 return; 268 269 /* 270 * Free this mbuf back to the mbuf zone with all m_ext 271 * information purged. 272 */ 273 m->m_ext.ext_buf = NULL; 274 m->m_ext.ext_free = NULL; 275 m->m_ext.ext_arg1 = NULL; 276 m->m_ext.ext_arg2 = NULL; 277 m->m_ext.ref_cnt = NULL; 278 m->m_ext.ext_size = 0; 279 m->m_ext.ext_type = 0; 280 m->m_flags &= ~M_EXT; 281 uma_zfree(zone_mbuf, m); 282 } 283 284 /* 285 * Attach the the cluster from *m to *n, set up m_ext in *n 286 * and bump the refcount of the cluster. 287 */ 288 static void 289 mb_dupcl(struct mbuf *n, struct mbuf *m) 290 { 291 KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__)); 292 KASSERT(m->m_ext.ref_cnt != NULL, ("%s: ref_cnt not set", __func__)); 293 KASSERT((n->m_flags & M_EXT) == 0, ("%s: M_EXT set", __func__)); 294 295 if (*(m->m_ext.ref_cnt) == 1) 296 *(m->m_ext.ref_cnt) += 1; 297 else 298 atomic_add_int(m->m_ext.ref_cnt, 1); 299 n->m_ext.ext_buf = m->m_ext.ext_buf; 300 n->m_ext.ext_free = m->m_ext.ext_free; 301 n->m_ext.ext_arg1 = m->m_ext.ext_arg1; 302 n->m_ext.ext_arg2 = m->m_ext.ext_arg2; 303 n->m_ext.ext_size = m->m_ext.ext_size; 304 n->m_ext.ref_cnt = m->m_ext.ref_cnt; 305 n->m_ext.ext_type = m->m_ext.ext_type; 306 n->m_flags |= M_EXT; 307 } 308 309 /* 310 * Clean up mbuf (chain) from any tags and packet headers. 311 * If "all" is set then the first mbuf in the chain will be 312 * cleaned too. 313 */ 314 void 315 m_demote(struct mbuf *m0, int all) 316 { 317 struct mbuf *m; 318 319 for (m = all ? m0 : m0->m_next; m != NULL; m = m->m_next) { 320 if (m->m_flags & M_PKTHDR) { 321 m_tag_delete_chain(m, NULL); 322 m->m_flags &= ~M_PKTHDR; 323 bzero(&m->m_pkthdr, sizeof(struct pkthdr)); 324 } 325 if (m->m_type == MT_HEADER) 326 m->m_type = MT_DATA; 327 if (m != m0 && m->m_nextpkt != NULL) 328 m->m_nextpkt = NULL; 329 m->m_flags = m->m_flags & (M_EXT|M_EOR|M_RDONLY|M_FREELIST); 330 } 331 } 332 333 /* 334 * Sanity checks on mbuf (chain) for use in KASSERT() and general 335 * debugging. 336 * Returns 0 or panics when bad and 1 on all tests passed. 337 * Sanitize, 0 to run M_SANITY_ACTION, 1 to garble things so they 338 * blow up later. 339 */ 340 int 341 m_sanity(struct mbuf *m0, int sanitize) 342 { 343 struct mbuf *m; 344 caddr_t a, b; 345 int pktlen = 0; 346 347 #ifdef INVARIANTS 348 #define M_SANITY_ACTION(s) panic("mbuf %p: " s, m) 349 #else 350 #define M_SANITY_ACTION(s) printf("mbuf %p: " s, m) 351 #endif 352 353 for (m = m0; m != NULL; m = m->m_next) { 354 /* 355 * Basic pointer checks. If any of these fails then some 356 * unrelated kernel memory before or after us is trashed. 357 * No way to recover from that. 358 */ 359 a = ((m->m_flags & M_EXT) ? m->m_ext.ext_buf : 360 ((m->m_flags & M_PKTHDR) ? (caddr_t)(&m->m_pktdat) : 361 (caddr_t)(&m->m_dat)) ); 362 b = (caddr_t)(a + (m->m_flags & M_EXT ? m->m_ext.ext_size : 363 ((m->m_flags & M_PKTHDR) ? MHLEN : MLEN))); 364 if ((caddr_t)m->m_data < a) 365 M_SANITY_ACTION("m_data outside mbuf data range left"); 366 if ((caddr_t)m->m_data > b) 367 M_SANITY_ACTION("m_data outside mbuf data range right"); 368 if ((caddr_t)m->m_data + m->m_len > b) 369 M_SANITY_ACTION("m_data + m_len exeeds mbuf space"); 370 if ((m->m_flags & M_PKTHDR) && m->m_pkthdr.header) { 371 if ((caddr_t)m->m_pkthdr.header < a || 372 (caddr_t)m->m_pkthdr.header > b) 373 M_SANITY_ACTION("m_pkthdr.header outside mbuf data range"); 374 } 375 376 /* m->m_nextpkt may only be set on first mbuf in chain. */ 377 if (m != m0 && m->m_nextpkt != NULL) { 378 if (sanitize) { 379 m_freem(m->m_nextpkt); 380 m->m_nextpkt = (struct mbuf *)0xDEADC0DE; 381 } else 382 M_SANITY_ACTION("m->m_nextpkt on in-chain mbuf"); 383 } 384 385 /* packet length (not mbuf length!) calculation */ 386 if (m0->m_flags & M_PKTHDR) 387 pktlen += m->m_len; 388 389 /* m_tags may only be attached to first mbuf in chain. */ 390 if (m != m0 && m->m_flags & M_PKTHDR && 391 !SLIST_EMPTY(&m->m_pkthdr.tags)) { 392 if (sanitize) { 393 m_tag_delete_chain(m, NULL); 394 /* put in 0xDEADC0DE perhaps? */ 395 } else 396 M_SANITY_ACTION("m_tags on in-chain mbuf"); 397 } 398 399 /* M_PKTHDR may only be set on first mbuf in chain */ 400 if (m != m0 && m->m_flags & M_PKTHDR) { 401 if (sanitize) { 402 bzero(&m->m_pkthdr, sizeof(m->m_pkthdr)); 403 m->m_flags &= ~M_PKTHDR; 404 /* put in 0xDEADCODE and leave hdr flag in */ 405 } else 406 M_SANITY_ACTION("M_PKTHDR on in-chain mbuf"); 407 } 408 } 409 m = m0; 410 if (pktlen && pktlen != m->m_pkthdr.len) { 411 if (sanitize) 412 m->m_pkthdr.len = 0; 413 else 414 M_SANITY_ACTION("m_pkthdr.len != mbuf chain length"); 415 } 416 return 1; 417 418 #undef M_SANITY_ACTION 419 } 420 421 422 /* 423 * "Move" mbuf pkthdr from "from" to "to". 424 * "from" must have M_PKTHDR set, and "to" must be empty. 425 */ 426 void 427 m_move_pkthdr(struct mbuf *to, struct mbuf *from) 428 { 429 430 #if 0 431 /* see below for why these are not enabled */ 432 M_ASSERTPKTHDR(to); 433 /* Note: with MAC, this may not be a good assertion. */ 434 KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), 435 ("m_move_pkthdr: to has tags")); 436 #endif 437 #ifdef MAC 438 /* 439 * XXXMAC: It could be this should also occur for non-MAC? 440 */ 441 if (to->m_flags & M_PKTHDR) 442 m_tag_delete_chain(to, NULL); 443 #endif 444 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT); 445 if ((to->m_flags & M_EXT) == 0) 446 to->m_data = to->m_pktdat; 447 to->m_pkthdr = from->m_pkthdr; /* especially tags */ 448 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */ 449 from->m_flags &= ~M_PKTHDR; 450 } 451 452 /* 453 * Duplicate "from"'s mbuf pkthdr in "to". 454 * "from" must have M_PKTHDR set, and "to" must be empty. 455 * In particular, this does a deep copy of the packet tags. 456 */ 457 int 458 m_dup_pkthdr(struct mbuf *to, struct mbuf *from, int how) 459 { 460 461 #if 0 462 /* 463 * The mbuf allocator only initializes the pkthdr 464 * when the mbuf is allocated with MGETHDR. Many users 465 * (e.g. m_copy*, m_prepend) use MGET and then 466 * smash the pkthdr as needed causing these 467 * assertions to trip. For now just disable them. 468 */ 469 M_ASSERTPKTHDR(to); 470 /* Note: with MAC, this may not be a good assertion. */ 471 KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_dup_pkthdr: to has tags")); 472 #endif 473 MBUF_CHECKSLEEP(how); 474 #ifdef MAC 475 if (to->m_flags & M_PKTHDR) 476 m_tag_delete_chain(to, NULL); 477 #endif 478 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT); 479 if ((to->m_flags & M_EXT) == 0) 480 to->m_data = to->m_pktdat; 481 to->m_pkthdr = from->m_pkthdr; 482 SLIST_INIT(&to->m_pkthdr.tags); 483 return (m_tag_copy_chain(to, from, MBTOM(how))); 484 } 485 486 /* 487 * Lesser-used path for M_PREPEND: 488 * allocate new mbuf to prepend to chain, 489 * copy junk along. 490 */ 491 struct mbuf * 492 m_prepend(struct mbuf *m, int len, int how) 493 { 494 struct mbuf *mn; 495 496 if (m->m_flags & M_PKTHDR) 497 MGETHDR(mn, how, m->m_type); 498 else 499 MGET(mn, how, m->m_type); 500 if (mn == NULL) { 501 m_freem(m); 502 return (NULL); 503 } 504 if (m->m_flags & M_PKTHDR) 505 M_MOVE_PKTHDR(mn, m); 506 mn->m_next = m; 507 m = mn; 508 if(m->m_flags & M_PKTHDR) { 509 if (len < MHLEN) 510 MH_ALIGN(m, len); 511 } else { 512 if (len < MLEN) 513 M_ALIGN(m, len); 514 } 515 m->m_len = len; 516 return (m); 517 } 518 519 /* 520 * Make a copy of an mbuf chain starting "off0" bytes from the beginning, 521 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf. 522 * The wait parameter is a choice of M_TRYWAIT/M_DONTWAIT from caller. 523 * Note that the copy is read-only, because clusters are not copied, 524 * only their reference counts are incremented. 525 */ 526 struct mbuf * 527 m_copym(struct mbuf *m, int off0, int len, int wait) 528 { 529 struct mbuf *n, **np; 530 int off = off0; 531 struct mbuf *top; 532 int copyhdr = 0; 533 534 KASSERT(off >= 0, ("m_copym, negative off %d", off)); 535 KASSERT(len >= 0, ("m_copym, negative len %d", len)); 536 MBUF_CHECKSLEEP(wait); 537 if (off == 0 && m->m_flags & M_PKTHDR) 538 copyhdr = 1; 539 while (off > 0) { 540 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain")); 541 if (off < m->m_len) 542 break; 543 off -= m->m_len; 544 m = m->m_next; 545 } 546 np = ⊤ 547 top = 0; 548 while (len > 0) { 549 if (m == NULL) { 550 KASSERT(len == M_COPYALL, 551 ("m_copym, length > size of mbuf chain")); 552 break; 553 } 554 if (copyhdr) 555 MGETHDR(n, wait, m->m_type); 556 else 557 MGET(n, wait, m->m_type); 558 *np = n; 559 if (n == NULL) 560 goto nospace; 561 if (copyhdr) { 562 if (!m_dup_pkthdr(n, m, wait)) 563 goto nospace; 564 if (len == M_COPYALL) 565 n->m_pkthdr.len -= off0; 566 else 567 n->m_pkthdr.len = len; 568 copyhdr = 0; 569 } 570 n->m_len = min(len, m->m_len - off); 571 if (m->m_flags & M_EXT) { 572 n->m_data = m->m_data + off; 573 mb_dupcl(n, m); 574 } else 575 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t), 576 (u_int)n->m_len); 577 if (len != M_COPYALL) 578 len -= n->m_len; 579 off = 0; 580 m = m->m_next; 581 np = &n->m_next; 582 } 583 if (top == NULL) 584 mbstat.m_mcfail++; /* XXX: No consistency. */ 585 586 return (top); 587 nospace: 588 m_freem(top); 589 mbstat.m_mcfail++; /* XXX: No consistency. */ 590 return (NULL); 591 } 592 593 /* 594 * Returns mbuf chain with new head for the prepending case. 595 * Copies from mbuf (chain) n from off for len to mbuf (chain) m 596 * either prepending or appending the data. 597 * The resulting mbuf (chain) m is fully writeable. 598 * m is destination (is made writeable) 599 * n is source, off is offset in source, len is len from offset 600 * dir, 0 append, 1 prepend 601 * how, wait or nowait 602 */ 603 604 static int 605 m_bcopyxxx(void *s, void *t, u_int len) 606 { 607 bcopy(s, t, (size_t)len); 608 return 0; 609 } 610 611 struct mbuf * 612 m_copymdata(struct mbuf *m, struct mbuf *n, int off, int len, 613 int prep, int how) 614 { 615 struct mbuf *mm, *x, *z, *prev = NULL; 616 caddr_t p; 617 int i, nlen = 0; 618 caddr_t buf[MLEN]; 619 620 KASSERT(m != NULL && n != NULL, ("m_copymdata, no target or source")); 621 KASSERT(off >= 0, ("m_copymdata, negative off %d", off)); 622 KASSERT(len >= 0, ("m_copymdata, negative len %d", len)); 623 KASSERT(prep == 0 || prep == 1, ("m_copymdata, unknown direction %d", prep)); 624 625 mm = m; 626 if (!prep) { 627 while(mm->m_next) { 628 prev = mm; 629 mm = mm->m_next; 630 } 631 } 632 for (z = n; z != NULL; z = z->m_next) 633 nlen += z->m_len; 634 if (len == M_COPYALL) 635 len = nlen - off; 636 if (off + len > nlen || len < 1) 637 return NULL; 638 639 if (!M_WRITABLE(mm)) { 640 /* XXX: Use proper m_xxx function instead. */ 641 x = m_getcl(how, MT_DATA, mm->m_flags); 642 if (x == NULL) 643 return NULL; 644 bcopy(mm->m_ext.ext_buf, x->m_ext.ext_buf, x->m_ext.ext_size); 645 p = x->m_ext.ext_buf + (mm->m_data - mm->m_ext.ext_buf); 646 x->m_data = p; 647 mm->m_next = NULL; 648 if (mm != m) 649 prev->m_next = x; 650 m_free(mm); 651 mm = x; 652 } 653 654 /* 655 * Append/prepend the data. Allocating mbufs as necessary. 656 */ 657 /* Shortcut if enough free space in first/last mbuf. */ 658 if (!prep && M_TRAILINGSPACE(mm) >= len) { 659 m_apply(n, off, len, m_bcopyxxx, mtod(mm, caddr_t) + 660 mm->m_len); 661 mm->m_len += len; 662 mm->m_pkthdr.len += len; 663 return m; 664 } 665 if (prep && M_LEADINGSPACE(mm) >= len) { 666 mm->m_data = mtod(mm, caddr_t) - len; 667 m_apply(n, off, len, m_bcopyxxx, mtod(mm, caddr_t)); 668 mm->m_len += len; 669 mm->m_pkthdr.len += len; 670 return mm; 671 } 672 673 /* Expand first/last mbuf to cluster if possible. */ 674 if (!prep && !(mm->m_flags & M_EXT) && len > M_TRAILINGSPACE(mm)) { 675 bcopy(mm->m_data, &buf, mm->m_len); 676 m_clget(mm, how); 677 if (!(mm->m_flags & M_EXT)) 678 return NULL; 679 bcopy(&buf, mm->m_ext.ext_buf, mm->m_len); 680 mm->m_data = mm->m_ext.ext_buf; 681 mm->m_pkthdr.header = NULL; 682 } 683 if (prep && !(mm->m_flags & M_EXT) && len > M_LEADINGSPACE(mm)) { 684 bcopy(mm->m_data, &buf, mm->m_len); 685 m_clget(mm, how); 686 if (!(mm->m_flags & M_EXT)) 687 return NULL; 688 bcopy(&buf, (caddr_t *)mm->m_ext.ext_buf + 689 mm->m_ext.ext_size - mm->m_len, mm->m_len); 690 mm->m_data = (caddr_t)mm->m_ext.ext_buf + 691 mm->m_ext.ext_size - mm->m_len; 692 mm->m_pkthdr.header = NULL; 693 } 694 695 /* Append/prepend as many mbuf (clusters) as necessary to fit len. */ 696 if (!prep && len > M_TRAILINGSPACE(mm)) { 697 if (!m_getm(mm, len - M_TRAILINGSPACE(mm), how, MT_DATA)) 698 return NULL; 699 } 700 if (prep && len > M_LEADINGSPACE(mm)) { 701 if (!(z = m_getm(NULL, len - M_LEADINGSPACE(mm), how, MT_DATA))) 702 return NULL; 703 i = 0; 704 for (x = z; x != NULL; x = x->m_next) { 705 i += x->m_flags & M_EXT ? x->m_ext.ext_size : 706 (x->m_flags & M_PKTHDR ? MHLEN : MLEN); 707 if (!x->m_next) 708 break; 709 } 710 z->m_data += i - len; 711 m_move_pkthdr(mm, z); 712 x->m_next = mm; 713 mm = z; 714 } 715 716 /* Seek to start position in source mbuf. Optimization for long chains. */ 717 while (off > 0) { 718 if (off < n->m_len) 719 break; 720 off -= n->m_len; 721 n = n->m_next; 722 } 723 724 /* Copy data into target mbuf. */ 725 z = mm; 726 while (len > 0) { 727 KASSERT(z != NULL, ("m_copymdata, falling off target edge")); 728 i = M_TRAILINGSPACE(z); 729 m_apply(n, off, i, m_bcopyxxx, mtod(z, caddr_t) + z->m_len); 730 z->m_len += i; 731 /* fixup pkthdr.len if necessary */ 732 if ((prep ? mm : m)->m_flags & M_PKTHDR) 733 (prep ? mm : m)->m_pkthdr.len += i; 734 off += i; 735 len -= i; 736 z = z->m_next; 737 } 738 return (prep ? mm : m); 739 } 740 741 /* 742 * Copy an entire packet, including header (which must be present). 743 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'. 744 * Note that the copy is read-only, because clusters are not copied, 745 * only their reference counts are incremented. 746 * Preserve alignment of the first mbuf so if the creator has left 747 * some room at the beginning (e.g. for inserting protocol headers) 748 * the copies still have the room available. 749 */ 750 struct mbuf * 751 m_copypacket(struct mbuf *m, int how) 752 { 753 struct mbuf *top, *n, *o; 754 755 MBUF_CHECKSLEEP(how); 756 MGET(n, how, m->m_type); 757 top = n; 758 if (n == NULL) 759 goto nospace; 760 761 if (!m_dup_pkthdr(n, m, how)) 762 goto nospace; 763 n->m_len = m->m_len; 764 if (m->m_flags & M_EXT) { 765 n->m_data = m->m_data; 766 mb_dupcl(n, m); 767 } else { 768 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat ); 769 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 770 } 771 772 m = m->m_next; 773 while (m) { 774 MGET(o, how, m->m_type); 775 if (o == NULL) 776 goto nospace; 777 778 n->m_next = o; 779 n = n->m_next; 780 781 n->m_len = m->m_len; 782 if (m->m_flags & M_EXT) { 783 n->m_data = m->m_data; 784 mb_dupcl(n, m); 785 } else { 786 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 787 } 788 789 m = m->m_next; 790 } 791 return top; 792 nospace: 793 m_freem(top); 794 mbstat.m_mcfail++; /* XXX: No consistency. */ 795 return (NULL); 796 } 797 798 /* 799 * Copy data from an mbuf chain starting "off" bytes from the beginning, 800 * continuing for "len" bytes, into the indicated buffer. 801 */ 802 void 803 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp) 804 { 805 u_int count; 806 807 KASSERT(off >= 0, ("m_copydata, negative off %d", off)); 808 KASSERT(len >= 0, ("m_copydata, negative len %d", len)); 809 while (off > 0) { 810 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain")); 811 if (off < m->m_len) 812 break; 813 off -= m->m_len; 814 m = m->m_next; 815 } 816 while (len > 0) { 817 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain")); 818 count = min(m->m_len - off, len); 819 bcopy(mtod(m, caddr_t) + off, cp, count); 820 len -= count; 821 cp += count; 822 off = 0; 823 m = m->m_next; 824 } 825 } 826 827 /* 828 * Copy a packet header mbuf chain into a completely new chain, including 829 * copying any mbuf clusters. Use this instead of m_copypacket() when 830 * you need a writable copy of an mbuf chain. 831 */ 832 struct mbuf * 833 m_dup(struct mbuf *m, int how) 834 { 835 struct mbuf **p, *top = NULL; 836 int remain, moff, nsize; 837 838 MBUF_CHECKSLEEP(how); 839 /* Sanity check */ 840 if (m == NULL) 841 return (NULL); 842 M_ASSERTPKTHDR(m); 843 844 /* While there's more data, get a new mbuf, tack it on, and fill it */ 845 remain = m->m_pkthdr.len; 846 moff = 0; 847 p = ⊤ 848 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */ 849 struct mbuf *n; 850 851 /* Get the next new mbuf */ 852 if (remain >= MINCLSIZE) { 853 n = m_getcl(how, m->m_type, 0); 854 nsize = MCLBYTES; 855 } else { 856 n = m_get(how, m->m_type); 857 nsize = MLEN; 858 } 859 if (n == NULL) 860 goto nospace; 861 862 if (top == NULL) { /* First one, must be PKTHDR */ 863 if (!m_dup_pkthdr(n, m, how)) { 864 m_free(n); 865 goto nospace; 866 } 867 if ((n->m_flags & M_EXT) == 0) 868 nsize = MHLEN; 869 } 870 n->m_len = 0; 871 872 /* Link it into the new chain */ 873 *p = n; 874 p = &n->m_next; 875 876 /* Copy data from original mbuf(s) into new mbuf */ 877 while (n->m_len < nsize && m != NULL) { 878 int chunk = min(nsize - n->m_len, m->m_len - moff); 879 880 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk); 881 moff += chunk; 882 n->m_len += chunk; 883 remain -= chunk; 884 if (moff == m->m_len) { 885 m = m->m_next; 886 moff = 0; 887 } 888 } 889 890 /* Check correct total mbuf length */ 891 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL), 892 ("%s: bogus m_pkthdr.len", __func__)); 893 } 894 return (top); 895 896 nospace: 897 m_freem(top); 898 mbstat.m_mcfail++; /* XXX: No consistency. */ 899 return (NULL); 900 } 901 902 /* 903 * Concatenate mbuf chain n to m. 904 * Both chains must be of the same type (e.g. MT_DATA). 905 * Any m_pkthdr is not updated. 906 */ 907 void 908 m_cat(struct mbuf *m, struct mbuf *n) 909 { 910 while (m->m_next) 911 m = m->m_next; 912 while (n) { 913 if (m->m_flags & M_EXT || 914 m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) { 915 /* just join the two chains */ 916 m->m_next = n; 917 return; 918 } 919 /* splat the data from one into the other */ 920 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 921 (u_int)n->m_len); 922 m->m_len += n->m_len; 923 n = m_free(n); 924 } 925 } 926 927 void 928 m_adj(struct mbuf *mp, int req_len) 929 { 930 int len = req_len; 931 struct mbuf *m; 932 int count; 933 934 if ((m = mp) == NULL) 935 return; 936 if (len >= 0) { 937 /* 938 * Trim from head. 939 */ 940 while (m != NULL && len > 0) { 941 if (m->m_len <= len) { 942 len -= m->m_len; 943 m->m_len = 0; 944 m = m->m_next; 945 } else { 946 m->m_len -= len; 947 m->m_data += len; 948 len = 0; 949 } 950 } 951 m = mp; 952 if (mp->m_flags & M_PKTHDR) 953 m->m_pkthdr.len -= (req_len - len); 954 } else { 955 /* 956 * Trim from tail. Scan the mbuf chain, 957 * calculating its length and finding the last mbuf. 958 * If the adjustment only affects this mbuf, then just 959 * adjust and return. Otherwise, rescan and truncate 960 * after the remaining size. 961 */ 962 len = -len; 963 count = 0; 964 for (;;) { 965 count += m->m_len; 966 if (m->m_next == (struct mbuf *)0) 967 break; 968 m = m->m_next; 969 } 970 if (m->m_len >= len) { 971 m->m_len -= len; 972 if (mp->m_flags & M_PKTHDR) 973 mp->m_pkthdr.len -= len; 974 return; 975 } 976 count -= len; 977 if (count < 0) 978 count = 0; 979 /* 980 * Correct length for chain is "count". 981 * Find the mbuf with last data, adjust its length, 982 * and toss data from remaining mbufs on chain. 983 */ 984 m = mp; 985 if (m->m_flags & M_PKTHDR) 986 m->m_pkthdr.len = count; 987 for (; m; m = m->m_next) { 988 if (m->m_len >= count) { 989 m->m_len = count; 990 if (m->m_next != NULL) { 991 m_freem(m->m_next); 992 m->m_next = NULL; 993 } 994 break; 995 } 996 count -= m->m_len; 997 } 998 } 999 } 1000 1001 /* 1002 * Rearange an mbuf chain so that len bytes are contiguous 1003 * and in the data area of an mbuf (so that mtod and dtom 1004 * will work for a structure of size len). Returns the resulting 1005 * mbuf chain on success, frees it and returns null on failure. 1006 * If there is room, it will add up to max_protohdr-len extra bytes to the 1007 * contiguous region in an attempt to avoid being called next time. 1008 */ 1009 struct mbuf * 1010 m_pullup(struct mbuf *n, int len) 1011 { 1012 struct mbuf *m; 1013 int count; 1014 int space; 1015 1016 /* 1017 * If first mbuf has no cluster, and has room for len bytes 1018 * without shifting current data, pullup into it, 1019 * otherwise allocate a new mbuf to prepend to the chain. 1020 */ 1021 if ((n->m_flags & M_EXT) == 0 && 1022 n->m_data + len < &n->m_dat[MLEN] && n->m_next) { 1023 if (n->m_len >= len) 1024 return (n); 1025 m = n; 1026 n = n->m_next; 1027 len -= m->m_len; 1028 } else { 1029 if (len > MHLEN) 1030 goto bad; 1031 MGET(m, M_DONTWAIT, n->m_type); 1032 if (m == NULL) 1033 goto bad; 1034 m->m_len = 0; 1035 if (n->m_flags & M_PKTHDR) 1036 M_MOVE_PKTHDR(m, n); 1037 } 1038 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 1039 do { 1040 count = min(min(max(len, max_protohdr), space), n->m_len); 1041 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 1042 (u_int)count); 1043 len -= count; 1044 m->m_len += count; 1045 n->m_len -= count; 1046 space -= count; 1047 if (n->m_len) 1048 n->m_data += count; 1049 else 1050 n = m_free(n); 1051 } while (len > 0 && n); 1052 if (len > 0) { 1053 (void) m_free(m); 1054 goto bad; 1055 } 1056 m->m_next = n; 1057 return (m); 1058 bad: 1059 m_freem(n); 1060 mbstat.m_mpfail++; /* XXX: No consistency. */ 1061 return (NULL); 1062 } 1063 1064 /* 1065 * Like m_pullup(), except a new mbuf is always allocated, and we allow 1066 * the amount of empty space before the data in the new mbuf to be specified 1067 * (in the event that the caller expects to prepend later). 1068 */ 1069 int MSFail; 1070 1071 struct mbuf * 1072 m_copyup(struct mbuf *n, int len, int dstoff) 1073 { 1074 struct mbuf *m; 1075 int count, space; 1076 1077 if (len > (MHLEN - dstoff)) 1078 goto bad; 1079 MGET(m, M_DONTWAIT, n->m_type); 1080 if (m == NULL) 1081 goto bad; 1082 m->m_len = 0; 1083 if (n->m_flags & M_PKTHDR) 1084 M_MOVE_PKTHDR(m, n); 1085 m->m_data += dstoff; 1086 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 1087 do { 1088 count = min(min(max(len, max_protohdr), space), n->m_len); 1089 memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t), 1090 (unsigned)count); 1091 len -= count; 1092 m->m_len += count; 1093 n->m_len -= count; 1094 space -= count; 1095 if (n->m_len) 1096 n->m_data += count; 1097 else 1098 n = m_free(n); 1099 } while (len > 0 && n); 1100 if (len > 0) { 1101 (void) m_free(m); 1102 goto bad; 1103 } 1104 m->m_next = n; 1105 return (m); 1106 bad: 1107 m_freem(n); 1108 MSFail++; 1109 return (NULL); 1110 } 1111 1112 /* 1113 * Partition an mbuf chain in two pieces, returning the tail -- 1114 * all but the first len0 bytes. In case of failure, it returns NULL and 1115 * attempts to restore the chain to its original state. 1116 * 1117 * Note that the resulting mbufs might be read-only, because the new 1118 * mbuf can end up sharing an mbuf cluster with the original mbuf if 1119 * the "breaking point" happens to lie within a cluster mbuf. Use the 1120 * M_WRITABLE() macro to check for this case. 1121 */ 1122 struct mbuf * 1123 m_split(struct mbuf *m0, int len0, int wait) 1124 { 1125 struct mbuf *m, *n; 1126 u_int len = len0, remain; 1127 1128 MBUF_CHECKSLEEP(wait); 1129 for (m = m0; m && len > m->m_len; m = m->m_next) 1130 len -= m->m_len; 1131 if (m == NULL) 1132 return (NULL); 1133 remain = m->m_len - len; 1134 if (m0->m_flags & M_PKTHDR) { 1135 MGETHDR(n, wait, m0->m_type); 1136 if (n == NULL) 1137 return (NULL); 1138 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; 1139 n->m_pkthdr.len = m0->m_pkthdr.len - len0; 1140 m0->m_pkthdr.len = len0; 1141 if (m->m_flags & M_EXT) 1142 goto extpacket; 1143 if (remain > MHLEN) { 1144 /* m can't be the lead packet */ 1145 MH_ALIGN(n, 0); 1146 n->m_next = m_split(m, len, wait); 1147 if (n->m_next == NULL) { 1148 (void) m_free(n); 1149 return (NULL); 1150 } else { 1151 n->m_len = 0; 1152 return (n); 1153 } 1154 } else 1155 MH_ALIGN(n, remain); 1156 } else if (remain == 0) { 1157 n = m->m_next; 1158 m->m_next = NULL; 1159 return (n); 1160 } else { 1161 MGET(n, wait, m->m_type); 1162 if (n == NULL) 1163 return (NULL); 1164 M_ALIGN(n, remain); 1165 } 1166 extpacket: 1167 if (m->m_flags & M_EXT) { 1168 n->m_data = m->m_data + len; 1169 mb_dupcl(n, m); 1170 } else { 1171 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain); 1172 } 1173 n->m_len = remain; 1174 m->m_len = len; 1175 n->m_next = m->m_next; 1176 m->m_next = NULL; 1177 return (n); 1178 } 1179 /* 1180 * Routine to copy from device local memory into mbufs. 1181 * Note that `off' argument is offset into first mbuf of target chain from 1182 * which to begin copying the data to. 1183 */ 1184 struct mbuf * 1185 m_devget(char *buf, int totlen, int off, struct ifnet *ifp, 1186 void (*copy)(char *from, caddr_t to, u_int len)) 1187 { 1188 struct mbuf *m; 1189 struct mbuf *top = NULL, **mp = ⊤ 1190 int len; 1191 1192 if (off < 0 || off > MHLEN) 1193 return (NULL); 1194 1195 while (totlen > 0) { 1196 if (top == NULL) { /* First one, must be PKTHDR */ 1197 if (totlen + off >= MINCLSIZE) { 1198 m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR); 1199 len = MCLBYTES; 1200 } else { 1201 m = m_gethdr(M_DONTWAIT, MT_DATA); 1202 len = MHLEN; 1203 1204 /* Place initial small packet/header at end of mbuf */ 1205 if (m && totlen + off + max_linkhdr <= MLEN) { 1206 m->m_data += max_linkhdr; 1207 len -= max_linkhdr; 1208 } 1209 } 1210 if (m == NULL) 1211 return NULL; 1212 m->m_pkthdr.rcvif = ifp; 1213 m->m_pkthdr.len = totlen; 1214 } else { 1215 if (totlen + off >= MINCLSIZE) { 1216 m = m_getcl(M_DONTWAIT, MT_DATA, 0); 1217 len = MCLBYTES; 1218 } else { 1219 m = m_get(M_DONTWAIT, MT_DATA); 1220 len = MLEN; 1221 } 1222 if (m == NULL) { 1223 m_freem(top); 1224 return NULL; 1225 } 1226 } 1227 if (off) { 1228 m->m_data += off; 1229 len -= off; 1230 off = 0; 1231 } 1232 m->m_len = len = min(totlen, len); 1233 if (copy) 1234 copy(buf, mtod(m, caddr_t), (u_int)len); 1235 else 1236 bcopy(buf, mtod(m, caddr_t), (u_int)len); 1237 buf += len; 1238 *mp = m; 1239 mp = &m->m_next; 1240 totlen -= len; 1241 } 1242 return (top); 1243 } 1244 1245 /* 1246 * Copy data from a buffer back into the indicated mbuf chain, 1247 * starting "off" bytes from the beginning, extending the mbuf 1248 * chain if necessary. 1249 */ 1250 void 1251 m_copyback(struct mbuf *m0, int off, int len, c_caddr_t cp) 1252 { 1253 int mlen; 1254 struct mbuf *m = m0, *n; 1255 int totlen = 0; 1256 1257 if (m0 == NULL) 1258 return; 1259 while (off > (mlen = m->m_len)) { 1260 off -= mlen; 1261 totlen += mlen; 1262 if (m->m_next == NULL) { 1263 n = m_get(M_DONTWAIT, m->m_type); 1264 if (n == NULL) 1265 goto out; 1266 bzero(mtod(n, caddr_t), MLEN); 1267 n->m_len = min(MLEN, len + off); 1268 m->m_next = n; 1269 } 1270 m = m->m_next; 1271 } 1272 while (len > 0) { 1273 mlen = min (m->m_len - off, len); 1274 bcopy(cp, off + mtod(m, caddr_t), (u_int)mlen); 1275 cp += mlen; 1276 len -= mlen; 1277 mlen += off; 1278 off = 0; 1279 totlen += mlen; 1280 if (len == 0) 1281 break; 1282 if (m->m_next == NULL) { 1283 n = m_get(M_DONTWAIT, m->m_type); 1284 if (n == NULL) 1285 break; 1286 n->m_len = min(MLEN, len); 1287 m->m_next = n; 1288 } 1289 m = m->m_next; 1290 } 1291 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) 1292 m->m_pkthdr.len = totlen; 1293 } 1294 1295 /* 1296 * Append the specified data to the indicated mbuf chain, 1297 * Extend the mbuf chain if the new data does not fit in 1298 * existing space. 1299 * 1300 * Return 1 if able to complete the job; otherwise 0. 1301 */ 1302 int 1303 m_append(struct mbuf *m0, int len, c_caddr_t cp) 1304 { 1305 struct mbuf *m, *n; 1306 int remainder, space; 1307 1308 for (m = m0; m->m_next != NULL; m = m->m_next) 1309 ; 1310 remainder = len; 1311 space = M_TRAILINGSPACE(m); 1312 if (space > 0) { 1313 /* 1314 * Copy into available space. 1315 */ 1316 if (space > remainder) 1317 space = remainder; 1318 bcopy(cp, mtod(m, caddr_t) + m->m_len, space); 1319 m->m_len += space; 1320 cp += space, remainder -= space; 1321 } 1322 while (remainder > 0) { 1323 /* 1324 * Allocate a new mbuf; could check space 1325 * and allocate a cluster instead. 1326 */ 1327 n = m_get(M_DONTWAIT, m->m_type); 1328 if (n == NULL) 1329 break; 1330 n->m_len = min(MLEN, remainder); 1331 bcopy(cp, mtod(n, caddr_t), n->m_len); 1332 cp += n->m_len, remainder -= n->m_len; 1333 m->m_next = n; 1334 m = n; 1335 } 1336 if (m0->m_flags & M_PKTHDR) 1337 m0->m_pkthdr.len += len - remainder; 1338 return (remainder == 0); 1339 } 1340 1341 /* 1342 * Apply function f to the data in an mbuf chain starting "off" bytes from 1343 * the beginning, continuing for "len" bytes. 1344 */ 1345 int 1346 m_apply(struct mbuf *m, int off, int len, 1347 int (*f)(void *, void *, u_int), void *arg) 1348 { 1349 u_int count; 1350 int rval; 1351 1352 KASSERT(off >= 0, ("m_apply, negative off %d", off)); 1353 KASSERT(len >= 0, ("m_apply, negative len %d", len)); 1354 while (off > 0) { 1355 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain")); 1356 if (off < m->m_len) 1357 break; 1358 off -= m->m_len; 1359 m = m->m_next; 1360 } 1361 while (len > 0) { 1362 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain")); 1363 count = min(m->m_len - off, len); 1364 rval = (*f)(arg, mtod(m, caddr_t) + off, count); 1365 if (rval) 1366 return (rval); 1367 len -= count; 1368 off = 0; 1369 m = m->m_next; 1370 } 1371 return (0); 1372 } 1373 1374 /* 1375 * Return a pointer to mbuf/offset of location in mbuf chain. 1376 */ 1377 struct mbuf * 1378 m_getptr(struct mbuf *m, int loc, int *off) 1379 { 1380 1381 while (loc >= 0) { 1382 /* Normal end of search. */ 1383 if (m->m_len > loc) { 1384 *off = loc; 1385 return (m); 1386 } else { 1387 loc -= m->m_len; 1388 if (m->m_next == NULL) { 1389 if (loc == 0) { 1390 /* Point at the end of valid data. */ 1391 *off = m->m_len; 1392 return (m); 1393 } 1394 return (NULL); 1395 } 1396 m = m->m_next; 1397 } 1398 } 1399 return (NULL); 1400 } 1401 1402 void 1403 m_print(const struct mbuf *m, int maxlen) 1404 { 1405 int len; 1406 int pdata; 1407 const struct mbuf *m2; 1408 1409 if (m->m_flags & M_PKTHDR) 1410 len = m->m_pkthdr.len; 1411 else 1412 len = -1; 1413 m2 = m; 1414 while (m2 != NULL && (len == -1 || len)) { 1415 pdata = m2->m_len; 1416 if (maxlen != -1 && pdata > maxlen) 1417 pdata = maxlen; 1418 printf("mbuf: %p len: %d, next: %p, %b%s", m2, m2->m_len, 1419 m2->m_next, m2->m_flags, "\20\20freelist\17skipfw" 1420 "\11proto5\10proto4\7proto3\6proto2\5proto1\4rdonly" 1421 "\3eor\2pkthdr\1ext", pdata ? "" : "\n"); 1422 if (pdata) 1423 printf(", %*D\n", pdata, (u_char *)m2->m_data, "-"); 1424 if (len != -1) 1425 len -= m2->m_len; 1426 m2 = m2->m_next; 1427 } 1428 if (len > 0) 1429 printf("%d bytes unaccounted for.\n", len); 1430 return; 1431 } 1432 1433 u_int 1434 m_fixhdr(struct mbuf *m0) 1435 { 1436 u_int len; 1437 1438 len = m_length(m0, NULL); 1439 m0->m_pkthdr.len = len; 1440 return (len); 1441 } 1442 1443 u_int 1444 m_length(struct mbuf *m0, struct mbuf **last) 1445 { 1446 struct mbuf *m; 1447 u_int len; 1448 1449 len = 0; 1450 for (m = m0; m != NULL; m = m->m_next) { 1451 len += m->m_len; 1452 if (m->m_next == NULL) 1453 break; 1454 } 1455 if (last != NULL) 1456 *last = m; 1457 return (len); 1458 } 1459 1460 /* 1461 * Defragment a mbuf chain, returning the shortest possible 1462 * chain of mbufs and clusters. If allocation fails and 1463 * this cannot be completed, NULL will be returned, but 1464 * the passed in chain will be unchanged. Upon success, 1465 * the original chain will be freed, and the new chain 1466 * will be returned. 1467 * 1468 * If a non-packet header is passed in, the original 1469 * mbuf (chain?) will be returned unharmed. 1470 */ 1471 struct mbuf * 1472 m_defrag(struct mbuf *m0, int how) 1473 { 1474 struct mbuf *m_new = NULL, *m_final = NULL; 1475 int progress = 0, length; 1476 1477 MBUF_CHECKSLEEP(how); 1478 if (!(m0->m_flags & M_PKTHDR)) 1479 return (m0); 1480 1481 m_fixhdr(m0); /* Needed sanity check */ 1482 1483 #ifdef MBUF_STRESS_TEST 1484 if (m_defragrandomfailures) { 1485 int temp = arc4random() & 0xff; 1486 if (temp == 0xba) 1487 goto nospace; 1488 } 1489 #endif 1490 1491 if (m0->m_pkthdr.len > MHLEN) 1492 m_final = m_getcl(how, MT_DATA, M_PKTHDR); 1493 else 1494 m_final = m_gethdr(how, MT_DATA); 1495 1496 if (m_final == NULL) 1497 goto nospace; 1498 1499 if (m_dup_pkthdr(m_final, m0, how) == 0) 1500 goto nospace; 1501 1502 m_new = m_final; 1503 1504 while (progress < m0->m_pkthdr.len) { 1505 length = m0->m_pkthdr.len - progress; 1506 if (length > MCLBYTES) 1507 length = MCLBYTES; 1508 1509 if (m_new == NULL) { 1510 if (length > MLEN) 1511 m_new = m_getcl(how, MT_DATA, 0); 1512 else 1513 m_new = m_get(how, MT_DATA); 1514 if (m_new == NULL) 1515 goto nospace; 1516 } 1517 1518 m_copydata(m0, progress, length, mtod(m_new, caddr_t)); 1519 progress += length; 1520 m_new->m_len = length; 1521 if (m_new != m_final) 1522 m_cat(m_final, m_new); 1523 m_new = NULL; 1524 } 1525 #ifdef MBUF_STRESS_TEST 1526 if (m0->m_next == NULL) 1527 m_defraguseless++; 1528 #endif 1529 m_freem(m0); 1530 m0 = m_final; 1531 #ifdef MBUF_STRESS_TEST 1532 m_defragpackets++; 1533 m_defragbytes += m0->m_pkthdr.len; 1534 #endif 1535 return (m0); 1536 nospace: 1537 #ifdef MBUF_STRESS_TEST 1538 m_defragfailure++; 1539 #endif 1540 if (m_final) 1541 m_freem(m_final); 1542 return (NULL); 1543 } 1544 1545 /* 1546 * Defragment an mbuf chain, returning at most maxfrags separate 1547 * mbufs+clusters. If this is not possible NULL is returned and 1548 * the original mbuf chain is left in it's present (potentially 1549 * modified) state. We use two techniques: collapsing consecutive 1550 * mbufs and replacing consecutive mbufs by a cluster. 1551 * 1552 * NB: this should really be named m_defrag but that name is taken 1553 */ 1554 struct mbuf * 1555 m_collapse(struct mbuf *m0, int how, int maxfrags) 1556 { 1557 struct mbuf *m, *n, *n2, **prev; 1558 u_int curfrags; 1559 1560 /* 1561 * Calculate the current number of frags. 1562 */ 1563 curfrags = 0; 1564 for (m = m0; m != NULL; m = m->m_next) 1565 curfrags++; 1566 /* 1567 * First, try to collapse mbufs. Note that we always collapse 1568 * towards the front so we don't need to deal with moving the 1569 * pkthdr. This may be suboptimal if the first mbuf has much 1570 * less data than the following. 1571 */ 1572 m = m0; 1573 again: 1574 for (;;) { 1575 n = m->m_next; 1576 if (n == NULL) 1577 break; 1578 if ((m->m_flags & M_RDONLY) == 0 && 1579 n->m_len < M_TRAILINGSPACE(m)) { 1580 bcopy(mtod(n, void *), mtod(m, char *) + m->m_len, 1581 n->m_len); 1582 m->m_len += n->m_len; 1583 m->m_next = n->m_next; 1584 m_free(n); 1585 if (--curfrags <= maxfrags) 1586 return m0; 1587 } else 1588 m = n; 1589 } 1590 KASSERT(maxfrags > 1, 1591 ("maxfrags %u, but normal collapse failed", maxfrags)); 1592 /* 1593 * Collapse consecutive mbufs to a cluster. 1594 */ 1595 prev = &m0->m_next; /* NB: not the first mbuf */ 1596 while ((n = *prev) != NULL) { 1597 if ((n2 = n->m_next) != NULL && 1598 n->m_len + n2->m_len < MCLBYTES) { 1599 m = m_getcl(how, MT_DATA, 0); 1600 if (m == NULL) 1601 goto bad; 1602 bcopy(mtod(n, void *), mtod(m, void *), n->m_len); 1603 bcopy(mtod(n2, void *), mtod(m, char *) + n->m_len, 1604 n2->m_len); 1605 m->m_len = n->m_len + n2->m_len; 1606 m->m_next = n2->m_next; 1607 *prev = m; 1608 m_free(n); 1609 m_free(n2); 1610 if (--curfrags <= maxfrags) /* +1 cl -2 mbufs */ 1611 return m0; 1612 /* 1613 * Still not there, try the normal collapse 1614 * again before we allocate another cluster. 1615 */ 1616 goto again; 1617 } 1618 prev = &n->m_next; 1619 } 1620 /* 1621 * No place where we can collapse to a cluster; punt. 1622 * This can occur if, for example, you request 2 frags 1623 * but the packet requires that both be clusters (we 1624 * never reallocate the first mbuf to avoid moving the 1625 * packet header). 1626 */ 1627 bad: 1628 return NULL; 1629 } 1630 1631 #ifdef MBUF_STRESS_TEST 1632 1633 /* 1634 * Fragment an mbuf chain. There's no reason you'd ever want to do 1635 * this in normal usage, but it's great for stress testing various 1636 * mbuf consumers. 1637 * 1638 * If fragmentation is not possible, the original chain will be 1639 * returned. 1640 * 1641 * Possible length values: 1642 * 0 no fragmentation will occur 1643 * > 0 each fragment will be of the specified length 1644 * -1 each fragment will be the same random value in length 1645 * -2 each fragment's length will be entirely random 1646 * (Random values range from 1 to 256) 1647 */ 1648 struct mbuf * 1649 m_fragment(struct mbuf *m0, int how, int length) 1650 { 1651 struct mbuf *m_new = NULL, *m_final = NULL; 1652 int progress = 0; 1653 1654 if (!(m0->m_flags & M_PKTHDR)) 1655 return (m0); 1656 1657 if ((length == 0) || (length < -2)) 1658 return (m0); 1659 1660 m_fixhdr(m0); /* Needed sanity check */ 1661 1662 m_final = m_getcl(how, MT_DATA, M_PKTHDR); 1663 1664 if (m_final == NULL) 1665 goto nospace; 1666 1667 if (m_dup_pkthdr(m_final, m0, how) == 0) 1668 goto nospace; 1669 1670 m_new = m_final; 1671 1672 if (length == -1) 1673 length = 1 + (arc4random() & 255); 1674 1675 while (progress < m0->m_pkthdr.len) { 1676 int fraglen; 1677 1678 if (length > 0) 1679 fraglen = length; 1680 else 1681 fraglen = 1 + (arc4random() & 255); 1682 if (fraglen > m0->m_pkthdr.len - progress) 1683 fraglen = m0->m_pkthdr.len - progress; 1684 1685 if (fraglen > MCLBYTES) 1686 fraglen = MCLBYTES; 1687 1688 if (m_new == NULL) { 1689 m_new = m_getcl(how, MT_DATA, 0); 1690 if (m_new == NULL) 1691 goto nospace; 1692 } 1693 1694 m_copydata(m0, progress, fraglen, mtod(m_new, caddr_t)); 1695 progress += fraglen; 1696 m_new->m_len = fraglen; 1697 if (m_new != m_final) 1698 m_cat(m_final, m_new); 1699 m_new = NULL; 1700 } 1701 m_freem(m0); 1702 m0 = m_final; 1703 return (m0); 1704 nospace: 1705 if (m_final) 1706 m_freem(m_final); 1707 /* Return the original chain on failure */ 1708 return (m0); 1709 } 1710 1711 #endif 1712 1713 /* 1714 * Copy the contents of uio into a properly sized mbuf chain. 1715 */ 1716 struct mbuf * 1717 m_uiotombuf(struct uio *uio, int how, int len, int align, int flags) 1718 { 1719 struct mbuf *m, *mb; 1720 int error, length, total; 1721 int progress = 0; 1722 1723 /* 1724 * len can be zero or an arbitrary large value bound by 1725 * the total data supplied by the uio. 1726 */ 1727 if (len > 0) 1728 total = min(uio->uio_resid, len); 1729 else 1730 total = uio->uio_resid; 1731 1732 /* 1733 * The smallest unit returned by m_getm2() is a single mbuf 1734 * with pkthdr. We can't align past it. Align align itself. 1735 */ 1736 if (align) 1737 align &= ~(sizeof(long) - 1); 1738 if (align >= MHLEN) 1739 return (NULL); 1740 1741 /* 1742 * Give us the full allocation or nothing. 1743 * If len is zero return the smallest empty mbuf. 1744 */ 1745 m = m_getm2(NULL, max(total + align, 1), how, MT_DATA, flags); 1746 if (m == NULL) 1747 return (NULL); 1748 m->m_data += align; 1749 1750 /* Fill all mbufs with uio data and update header information. */ 1751 for (mb = m; mb != NULL; mb = mb->m_next) { 1752 length = min(M_TRAILINGSPACE(mb), total - progress); 1753 1754 error = uiomove(mtod(mb, void *), length, uio); 1755 if (error) { 1756 m_freem(m); 1757 return (NULL); 1758 } 1759 1760 mb->m_len = length; 1761 progress += length; 1762 if (flags & M_PKTHDR) 1763 m->m_pkthdr.len += length; 1764 } 1765 KASSERT(progress == total, ("%s: progress != total", __func__)); 1766 1767 return (m); 1768 } 1769 1770 /* 1771 * Set the m_data pointer of a newly-allocated mbuf 1772 * to place an object of the specified size at the 1773 * end of the mbuf, longword aligned. 1774 */ 1775 void 1776 m_align(struct mbuf *m, int len) 1777 { 1778 int adjust; 1779 1780 if (m->m_flags & M_EXT) 1781 adjust = m->m_ext.ext_size - len; 1782 else if (m->m_flags & M_PKTHDR) 1783 adjust = MHLEN - len; 1784 else 1785 adjust = MLEN - len; 1786 m->m_data += adjust &~ (sizeof(long)-1); 1787 } 1788 1789 /* 1790 * Create a writable copy of the mbuf chain. While doing this 1791 * we compact the chain with a goal of producing a chain with 1792 * at most two mbufs. The second mbuf in this chain is likely 1793 * to be a cluster. The primary purpose of this work is to create 1794 * a writable packet for encryption, compression, etc. The 1795 * secondary goal is to linearize the data so the data can be 1796 * passed to crypto hardware in the most efficient manner possible. 1797 */ 1798 struct mbuf * 1799 m_unshare(struct mbuf *m0, int how) 1800 { 1801 struct mbuf *m, *mprev; 1802 struct mbuf *n, *mfirst, *mlast; 1803 int len, off; 1804 1805 mprev = NULL; 1806 for (m = m0; m != NULL; m = mprev->m_next) { 1807 /* 1808 * Regular mbufs are ignored unless there's a cluster 1809 * in front of it that we can use to coalesce. We do 1810 * the latter mainly so later clusters can be coalesced 1811 * also w/o having to handle them specially (i.e. convert 1812 * mbuf+cluster -> cluster). This optimization is heavily 1813 * influenced by the assumption that we're running over 1814 * Ethernet where MCLBYTES is large enough that the max 1815 * packet size will permit lots of coalescing into a 1816 * single cluster. This in turn permits efficient 1817 * crypto operations, especially when using hardware. 1818 */ 1819 if ((m->m_flags & M_EXT) == 0) { 1820 if (mprev && (mprev->m_flags & M_EXT) && 1821 m->m_len <= M_TRAILINGSPACE(mprev)) { 1822 /* XXX: this ignores mbuf types */ 1823 memcpy(mtod(mprev, caddr_t) + mprev->m_len, 1824 mtod(m, caddr_t), m->m_len); 1825 mprev->m_len += m->m_len; 1826 mprev->m_next = m->m_next; /* unlink from chain */ 1827 m_free(m); /* reclaim mbuf */ 1828 #if 0 1829 newipsecstat.ips_mbcoalesced++; 1830 #endif 1831 } else { 1832 mprev = m; 1833 } 1834 continue; 1835 } 1836 /* 1837 * Writable mbufs are left alone (for now). 1838 */ 1839 if (M_WRITABLE(m)) { 1840 mprev = m; 1841 continue; 1842 } 1843 1844 /* 1845 * Not writable, replace with a copy or coalesce with 1846 * the previous mbuf if possible (since we have to copy 1847 * it anyway, we try to reduce the number of mbufs and 1848 * clusters so that future work is easier). 1849 */ 1850 KASSERT(m->m_flags & M_EXT, ("m_flags 0x%x", m->m_flags)); 1851 /* NB: we only coalesce into a cluster or larger */ 1852 if (mprev != NULL && (mprev->m_flags & M_EXT) && 1853 m->m_len <= M_TRAILINGSPACE(mprev)) { 1854 /* XXX: this ignores mbuf types */ 1855 memcpy(mtod(mprev, caddr_t) + mprev->m_len, 1856 mtod(m, caddr_t), m->m_len); 1857 mprev->m_len += m->m_len; 1858 mprev->m_next = m->m_next; /* unlink from chain */ 1859 m_free(m); /* reclaim mbuf */ 1860 #if 0 1861 newipsecstat.ips_clcoalesced++; 1862 #endif 1863 continue; 1864 } 1865 1866 /* 1867 * Allocate new space to hold the copy... 1868 */ 1869 /* XXX why can M_PKTHDR be set past the first mbuf? */ 1870 if (mprev == NULL && (m->m_flags & M_PKTHDR)) { 1871 /* 1872 * NB: if a packet header is present we must 1873 * allocate the mbuf separately from any cluster 1874 * because M_MOVE_PKTHDR will smash the data 1875 * pointer and drop the M_EXT marker. 1876 */ 1877 MGETHDR(n, how, m->m_type); 1878 if (n == NULL) { 1879 m_freem(m0); 1880 return (NULL); 1881 } 1882 M_MOVE_PKTHDR(n, m); 1883 MCLGET(n, how); 1884 if ((n->m_flags & M_EXT) == 0) { 1885 m_free(n); 1886 m_freem(m0); 1887 return (NULL); 1888 } 1889 } else { 1890 n = m_getcl(how, m->m_type, m->m_flags); 1891 if (n == NULL) { 1892 m_freem(m0); 1893 return (NULL); 1894 } 1895 } 1896 /* 1897 * ... and copy the data. We deal with jumbo mbufs 1898 * (i.e. m_len > MCLBYTES) by splitting them into 1899 * clusters. We could just malloc a buffer and make 1900 * it external but too many device drivers don't know 1901 * how to break up the non-contiguous memory when 1902 * doing DMA. 1903 */ 1904 len = m->m_len; 1905 off = 0; 1906 mfirst = n; 1907 mlast = NULL; 1908 for (;;) { 1909 int cc = min(len, MCLBYTES); 1910 memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, cc); 1911 n->m_len = cc; 1912 if (mlast != NULL) 1913 mlast->m_next = n; 1914 mlast = n; 1915 #if 0 1916 newipsecstat.ips_clcopied++; 1917 #endif 1918 1919 len -= cc; 1920 if (len <= 0) 1921 break; 1922 off += cc; 1923 1924 n = m_getcl(how, m->m_type, m->m_flags); 1925 if (n == NULL) { 1926 m_freem(mfirst); 1927 m_freem(m0); 1928 return (NULL); 1929 } 1930 } 1931 n->m_next = m->m_next; 1932 if (mprev == NULL) 1933 m0 = mfirst; /* new head of chain */ 1934 else 1935 mprev->m_next = mfirst; /* replace old mbuf */ 1936 m_free(m); /* release old mbuf */ 1937 mprev = mfirst; 1938 } 1939 return (m0); 1940 } 1941