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_param.h" 36 #include "opt_mbuf_stress_test.h" 37 #include "opt_mbuf_profiling.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 * Ensure the correct size of various mbuf parameters. It could be off due 91 * to compiler-induced padding and alignment artifacts. 92 */ 93 CTASSERT(MSIZE - offsetof(struct mbuf, m_dat) == MLEN); 94 CTASSERT(MSIZE - offsetof(struct mbuf, m_pktdat) == MHLEN); 95 96 /* 97 * mbuf data storage should be 64-bit aligned regardless of architectural 98 * pointer size; check this is the case with and without a packet header. 99 */ 100 CTASSERT(offsetof(struct mbuf, m_dat) % 8 == 0); 101 CTASSERT(offsetof(struct mbuf, m_pktdat) % 8 == 0); 102 103 /* 104 * While the specific values here don't matter too much (i.e., +/- a few 105 * words), we do want to ensure that changes to these values are carefully 106 * reasoned about and properly documented. This is especially the case as 107 * network-protocol and device-driver modules encode these layouts, and must 108 * be recompiled if the structures change. Check these values at compile time 109 * against the ones documented in comments in mbuf.h. 110 * 111 * NB: Possibly they should be documented there via #define's and not just 112 * comments. 113 */ 114 #if defined(__LP64__) 115 CTASSERT(offsetof(struct mbuf, m_dat) == 32); 116 CTASSERT(sizeof(struct pkthdr) == 56); 117 CTASSERT(sizeof(struct m_ext) == 48); 118 #else 119 CTASSERT(offsetof(struct mbuf, m_dat) == 24); 120 CTASSERT(sizeof(struct pkthdr) == 48); 121 CTASSERT(sizeof(struct m_ext) == 28); 122 #endif 123 124 /* 125 * Assert that the queue(3) macros produce code of the same size as an old 126 * plain pointer does. 127 */ 128 #ifdef INVARIANTS 129 static struct mbuf m_assertbuf; 130 CTASSERT(sizeof(m_assertbuf.m_slist) == sizeof(m_assertbuf.m_next)); 131 CTASSERT(sizeof(m_assertbuf.m_stailq) == sizeof(m_assertbuf.m_next)); 132 CTASSERT(sizeof(m_assertbuf.m_slistpkt) == sizeof(m_assertbuf.m_nextpkt)); 133 CTASSERT(sizeof(m_assertbuf.m_stailqpkt) == sizeof(m_assertbuf.m_nextpkt)); 134 #endif 135 136 /* 137 * Attach the cluster from *m to *n, set up m_ext in *n 138 * and bump the refcount of the cluster. 139 */ 140 void 141 mb_dupcl(struct mbuf *n, const struct mbuf *m) 142 { 143 144 KASSERT(m->m_flags & M_EXT, ("%s: M_EXT not set on %p", __func__, m)); 145 KASSERT(!(n->m_flags & M_EXT), ("%s: M_EXT set on %p", __func__, n)); 146 147 switch (m->m_ext.ext_type) { 148 case EXT_SFBUF: 149 case EXT_SFBUF_NOCACHE: 150 sf_ext_ref(m->m_ext.ext_arg1, m->m_ext.ext_arg2); 151 break; 152 default: 153 KASSERT(m->m_ext.ext_cnt != NULL, 154 ("%s: no refcounting pointer on %p", __func__, m)); 155 if (*(m->m_ext.ext_cnt) == 1) 156 *(m->m_ext.ext_cnt) += 1; 157 else 158 atomic_add_int(m->m_ext.ext_cnt, 1); 159 } 160 161 n->m_ext = m->m_ext; 162 n->m_flags |= M_EXT; 163 n->m_flags |= m->m_flags & M_RDONLY; 164 } 165 166 void 167 m_demote_pkthdr(struct mbuf *m) 168 { 169 170 M_ASSERTPKTHDR(m); 171 172 m_tag_delete_chain(m, NULL); 173 m->m_flags &= ~M_PKTHDR; 174 bzero(&m->m_pkthdr, sizeof(struct pkthdr)); 175 } 176 177 /* 178 * Clean up mbuf (chain) from any tags and packet headers. 179 * If "all" is set then the first mbuf in the chain will be 180 * cleaned too. 181 */ 182 void 183 m_demote(struct mbuf *m0, int all, int flags) 184 { 185 struct mbuf *m; 186 187 for (m = all ? m0 : m0->m_next; m != NULL; m = m->m_next) { 188 KASSERT(m->m_nextpkt == NULL, ("%s: m_nextpkt in m %p, m0 %p", 189 __func__, m, m0)); 190 if (m->m_flags & M_PKTHDR) 191 m_demote_pkthdr(m); 192 m->m_flags = m->m_flags & (M_EXT | M_RDONLY | M_NOFREE | flags); 193 } 194 } 195 196 /* 197 * Sanity checks on mbuf (chain) for use in KASSERT() and general 198 * debugging. 199 * Returns 0 or panics when bad and 1 on all tests passed. 200 * Sanitize, 0 to run M_SANITY_ACTION, 1 to garble things so they 201 * blow up later. 202 */ 203 int 204 m_sanity(struct mbuf *m0, int sanitize) 205 { 206 struct mbuf *m; 207 caddr_t a, b; 208 int pktlen = 0; 209 210 #ifdef INVARIANTS 211 #define M_SANITY_ACTION(s) panic("mbuf %p: " s, m) 212 #else 213 #define M_SANITY_ACTION(s) printf("mbuf %p: " s, m) 214 #endif 215 216 for (m = m0; m != NULL; m = m->m_next) { 217 /* 218 * Basic pointer checks. If any of these fails then some 219 * unrelated kernel memory before or after us is trashed. 220 * No way to recover from that. 221 */ 222 a = M_START(m); 223 b = a + M_SIZE(m); 224 if ((caddr_t)m->m_data < a) 225 M_SANITY_ACTION("m_data outside mbuf data range left"); 226 if ((caddr_t)m->m_data > b) 227 M_SANITY_ACTION("m_data outside mbuf data range right"); 228 if ((caddr_t)m->m_data + m->m_len > b) 229 M_SANITY_ACTION("m_data + m_len exeeds mbuf space"); 230 231 /* m->m_nextpkt may only be set on first mbuf in chain. */ 232 if (m != m0 && m->m_nextpkt != NULL) { 233 if (sanitize) { 234 m_freem(m->m_nextpkt); 235 m->m_nextpkt = (struct mbuf *)0xDEADC0DE; 236 } else 237 M_SANITY_ACTION("m->m_nextpkt on in-chain mbuf"); 238 } 239 240 /* packet length (not mbuf length!) calculation */ 241 if (m0->m_flags & M_PKTHDR) 242 pktlen += m->m_len; 243 244 /* m_tags may only be attached to first mbuf in chain. */ 245 if (m != m0 && m->m_flags & M_PKTHDR && 246 !SLIST_EMPTY(&m->m_pkthdr.tags)) { 247 if (sanitize) { 248 m_tag_delete_chain(m, NULL); 249 /* put in 0xDEADC0DE perhaps? */ 250 } else 251 M_SANITY_ACTION("m_tags on in-chain mbuf"); 252 } 253 254 /* M_PKTHDR may only be set on first mbuf in chain */ 255 if (m != m0 && m->m_flags & M_PKTHDR) { 256 if (sanitize) { 257 bzero(&m->m_pkthdr, sizeof(m->m_pkthdr)); 258 m->m_flags &= ~M_PKTHDR; 259 /* put in 0xDEADCODE and leave hdr flag in */ 260 } else 261 M_SANITY_ACTION("M_PKTHDR on in-chain mbuf"); 262 } 263 } 264 m = m0; 265 if (pktlen && pktlen != m->m_pkthdr.len) { 266 if (sanitize) 267 m->m_pkthdr.len = 0; 268 else 269 M_SANITY_ACTION("m_pkthdr.len != mbuf chain length"); 270 } 271 return 1; 272 273 #undef M_SANITY_ACTION 274 } 275 276 /* 277 * Non-inlined part of m_init(). 278 */ 279 int 280 m_pkthdr_init(struct mbuf *m, int how) 281 { 282 #ifdef MAC 283 int error; 284 #endif 285 m->m_data = m->m_pktdat; 286 bzero(&m->m_pkthdr, sizeof(m->m_pkthdr)); 287 #ifdef MAC 288 /* If the label init fails, fail the alloc */ 289 error = mac_mbuf_init(m, how); 290 if (error) 291 return (error); 292 #endif 293 294 return (0); 295 } 296 297 /* 298 * "Move" mbuf pkthdr from "from" to "to". 299 * "from" must have M_PKTHDR set, and "to" must be empty. 300 */ 301 void 302 m_move_pkthdr(struct mbuf *to, struct mbuf *from) 303 { 304 305 #if 0 306 /* see below for why these are not enabled */ 307 M_ASSERTPKTHDR(to); 308 /* Note: with MAC, this may not be a good assertion. */ 309 KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), 310 ("m_move_pkthdr: to has tags")); 311 #endif 312 #ifdef MAC 313 /* 314 * XXXMAC: It could be this should also occur for non-MAC? 315 */ 316 if (to->m_flags & M_PKTHDR) 317 m_tag_delete_chain(to, NULL); 318 #endif 319 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT); 320 if ((to->m_flags & M_EXT) == 0) 321 to->m_data = to->m_pktdat; 322 to->m_pkthdr = from->m_pkthdr; /* especially tags */ 323 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */ 324 from->m_flags &= ~M_PKTHDR; 325 } 326 327 /* 328 * Duplicate "from"'s mbuf pkthdr in "to". 329 * "from" must have M_PKTHDR set, and "to" must be empty. 330 * In particular, this does a deep copy of the packet tags. 331 */ 332 int 333 m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how) 334 { 335 336 #if 0 337 /* 338 * The mbuf allocator only initializes the pkthdr 339 * when the mbuf is allocated with m_gethdr(). Many users 340 * (e.g. m_copy*, m_prepend) use m_get() and then 341 * smash the pkthdr as needed causing these 342 * assertions to trip. For now just disable them. 343 */ 344 M_ASSERTPKTHDR(to); 345 /* Note: with MAC, this may not be a good assertion. */ 346 KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_dup_pkthdr: to has tags")); 347 #endif 348 MBUF_CHECKSLEEP(how); 349 #ifdef MAC 350 if (to->m_flags & M_PKTHDR) 351 m_tag_delete_chain(to, NULL); 352 #endif 353 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT); 354 if ((to->m_flags & M_EXT) == 0) 355 to->m_data = to->m_pktdat; 356 to->m_pkthdr = from->m_pkthdr; 357 SLIST_INIT(&to->m_pkthdr.tags); 358 return (m_tag_copy_chain(to, from, how)); 359 } 360 361 /* 362 * Lesser-used path for M_PREPEND: 363 * allocate new mbuf to prepend to chain, 364 * copy junk along. 365 */ 366 struct mbuf * 367 m_prepend(struct mbuf *m, int len, int how) 368 { 369 struct mbuf *mn; 370 371 if (m->m_flags & M_PKTHDR) 372 mn = m_gethdr(how, m->m_type); 373 else 374 mn = m_get(how, m->m_type); 375 if (mn == NULL) { 376 m_freem(m); 377 return (NULL); 378 } 379 if (m->m_flags & M_PKTHDR) 380 m_move_pkthdr(mn, m); 381 mn->m_next = m; 382 m = mn; 383 if (len < M_SIZE(m)) 384 M_ALIGN(m, len); 385 m->m_len = len; 386 return (m); 387 } 388 389 /* 390 * Make a copy of an mbuf chain starting "off0" bytes from the beginning, 391 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf. 392 * The wait parameter is a choice of M_WAITOK/M_NOWAIT from caller. 393 * Note that the copy is read-only, because clusters are not copied, 394 * only their reference counts are incremented. 395 */ 396 struct mbuf * 397 m_copym(const struct mbuf *m, int off0, int len, int wait) 398 { 399 struct mbuf *n, **np; 400 int off = off0; 401 struct mbuf *top; 402 int copyhdr = 0; 403 404 KASSERT(off >= 0, ("m_copym, negative off %d", off)); 405 KASSERT(len >= 0, ("m_copym, negative len %d", len)); 406 MBUF_CHECKSLEEP(wait); 407 if (off == 0 && m->m_flags & M_PKTHDR) 408 copyhdr = 1; 409 while (off > 0) { 410 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain")); 411 if (off < m->m_len) 412 break; 413 off -= m->m_len; 414 m = m->m_next; 415 } 416 np = ⊤ 417 top = 0; 418 while (len > 0) { 419 if (m == NULL) { 420 KASSERT(len == M_COPYALL, 421 ("m_copym, length > size of mbuf chain")); 422 break; 423 } 424 if (copyhdr) 425 n = m_gethdr(wait, m->m_type); 426 else 427 n = m_get(wait, m->m_type); 428 *np = n; 429 if (n == NULL) 430 goto nospace; 431 if (copyhdr) { 432 if (!m_dup_pkthdr(n, m, wait)) 433 goto nospace; 434 if (len == M_COPYALL) 435 n->m_pkthdr.len -= off0; 436 else 437 n->m_pkthdr.len = len; 438 copyhdr = 0; 439 } 440 n->m_len = min(len, m->m_len - off); 441 if (m->m_flags & M_EXT) { 442 n->m_data = m->m_data + off; 443 mb_dupcl(n, m); 444 } else 445 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t), 446 (u_int)n->m_len); 447 if (len != M_COPYALL) 448 len -= n->m_len; 449 off = 0; 450 m = m->m_next; 451 np = &n->m_next; 452 } 453 454 return (top); 455 nospace: 456 m_freem(top); 457 return (NULL); 458 } 459 460 /* 461 * Copy an entire packet, including header (which must be present). 462 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'. 463 * Note that the copy is read-only, because clusters are not copied, 464 * only their reference counts are incremented. 465 * Preserve alignment of the first mbuf so if the creator has left 466 * some room at the beginning (e.g. for inserting protocol headers) 467 * the copies still have the room available. 468 */ 469 struct mbuf * 470 m_copypacket(struct mbuf *m, int how) 471 { 472 struct mbuf *top, *n, *o; 473 474 MBUF_CHECKSLEEP(how); 475 n = m_get(how, m->m_type); 476 top = n; 477 if (n == NULL) 478 goto nospace; 479 480 if (!m_dup_pkthdr(n, m, how)) 481 goto nospace; 482 n->m_len = m->m_len; 483 if (m->m_flags & M_EXT) { 484 n->m_data = m->m_data; 485 mb_dupcl(n, m); 486 } else { 487 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat ); 488 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 489 } 490 491 m = m->m_next; 492 while (m) { 493 o = m_get(how, m->m_type); 494 if (o == NULL) 495 goto nospace; 496 497 n->m_next = o; 498 n = n->m_next; 499 500 n->m_len = m->m_len; 501 if (m->m_flags & M_EXT) { 502 n->m_data = m->m_data; 503 mb_dupcl(n, m); 504 } else { 505 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 506 } 507 508 m = m->m_next; 509 } 510 return top; 511 nospace: 512 m_freem(top); 513 return (NULL); 514 } 515 516 /* 517 * Copy data from an mbuf chain starting "off" bytes from the beginning, 518 * continuing for "len" bytes, into the indicated buffer. 519 */ 520 void 521 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp) 522 { 523 u_int count; 524 525 KASSERT(off >= 0, ("m_copydata, negative off %d", off)); 526 KASSERT(len >= 0, ("m_copydata, negative len %d", len)); 527 while (off > 0) { 528 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain")); 529 if (off < m->m_len) 530 break; 531 off -= m->m_len; 532 m = m->m_next; 533 } 534 while (len > 0) { 535 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain")); 536 count = min(m->m_len - off, len); 537 bcopy(mtod(m, caddr_t) + off, cp, count); 538 len -= count; 539 cp += count; 540 off = 0; 541 m = m->m_next; 542 } 543 } 544 545 /* 546 * Copy a packet header mbuf chain into a completely new chain, including 547 * copying any mbuf clusters. Use this instead of m_copypacket() when 548 * you need a writable copy of an mbuf chain. 549 */ 550 struct mbuf * 551 m_dup(const struct mbuf *m, int how) 552 { 553 struct mbuf **p, *top = NULL; 554 int remain, moff, nsize; 555 556 MBUF_CHECKSLEEP(how); 557 /* Sanity check */ 558 if (m == NULL) 559 return (NULL); 560 M_ASSERTPKTHDR(m); 561 562 /* While there's more data, get a new mbuf, tack it on, and fill it */ 563 remain = m->m_pkthdr.len; 564 moff = 0; 565 p = ⊤ 566 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */ 567 struct mbuf *n; 568 569 /* Get the next new mbuf */ 570 if (remain >= MINCLSIZE) { 571 n = m_getcl(how, m->m_type, 0); 572 nsize = MCLBYTES; 573 } else { 574 n = m_get(how, m->m_type); 575 nsize = MLEN; 576 } 577 if (n == NULL) 578 goto nospace; 579 580 if (top == NULL) { /* First one, must be PKTHDR */ 581 if (!m_dup_pkthdr(n, m, how)) { 582 m_free(n); 583 goto nospace; 584 } 585 if ((n->m_flags & M_EXT) == 0) 586 nsize = MHLEN; 587 n->m_flags &= ~M_RDONLY; 588 } 589 n->m_len = 0; 590 591 /* Link it into the new chain */ 592 *p = n; 593 p = &n->m_next; 594 595 /* Copy data from original mbuf(s) into new mbuf */ 596 while (n->m_len < nsize && m != NULL) { 597 int chunk = min(nsize - n->m_len, m->m_len - moff); 598 599 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk); 600 moff += chunk; 601 n->m_len += chunk; 602 remain -= chunk; 603 if (moff == m->m_len) { 604 m = m->m_next; 605 moff = 0; 606 } 607 } 608 609 /* Check correct total mbuf length */ 610 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL), 611 ("%s: bogus m_pkthdr.len", __func__)); 612 } 613 return (top); 614 615 nospace: 616 m_freem(top); 617 return (NULL); 618 } 619 620 /* 621 * Concatenate mbuf chain n to m. 622 * Both chains must be of the same type (e.g. MT_DATA). 623 * Any m_pkthdr is not updated. 624 */ 625 void 626 m_cat(struct mbuf *m, struct mbuf *n) 627 { 628 while (m->m_next) 629 m = m->m_next; 630 while (n) { 631 if (!M_WRITABLE(m) || 632 M_TRAILINGSPACE(m) < n->m_len) { 633 /* just join the two chains */ 634 m->m_next = n; 635 return; 636 } 637 /* splat the data from one into the other */ 638 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 639 (u_int)n->m_len); 640 m->m_len += n->m_len; 641 n = m_free(n); 642 } 643 } 644 645 /* 646 * Concatenate two pkthdr mbuf chains. 647 */ 648 void 649 m_catpkt(struct mbuf *m, struct mbuf *n) 650 { 651 652 M_ASSERTPKTHDR(m); 653 M_ASSERTPKTHDR(n); 654 655 m->m_pkthdr.len += n->m_pkthdr.len; 656 m_demote(n, 1, 0); 657 658 m_cat(m, n); 659 } 660 661 void 662 m_adj(struct mbuf *mp, int req_len) 663 { 664 int len = req_len; 665 struct mbuf *m; 666 int count; 667 668 if ((m = mp) == NULL) 669 return; 670 if (len >= 0) { 671 /* 672 * Trim from head. 673 */ 674 while (m != NULL && len > 0) { 675 if (m->m_len <= len) { 676 len -= m->m_len; 677 m->m_len = 0; 678 m = m->m_next; 679 } else { 680 m->m_len -= len; 681 m->m_data += len; 682 len = 0; 683 } 684 } 685 if (mp->m_flags & M_PKTHDR) 686 mp->m_pkthdr.len -= (req_len - len); 687 } else { 688 /* 689 * Trim from tail. Scan the mbuf chain, 690 * calculating its length and finding the last mbuf. 691 * If the adjustment only affects this mbuf, then just 692 * adjust and return. Otherwise, rescan and truncate 693 * after the remaining size. 694 */ 695 len = -len; 696 count = 0; 697 for (;;) { 698 count += m->m_len; 699 if (m->m_next == (struct mbuf *)0) 700 break; 701 m = m->m_next; 702 } 703 if (m->m_len >= len) { 704 m->m_len -= len; 705 if (mp->m_flags & M_PKTHDR) 706 mp->m_pkthdr.len -= len; 707 return; 708 } 709 count -= len; 710 if (count < 0) 711 count = 0; 712 /* 713 * Correct length for chain is "count". 714 * Find the mbuf with last data, adjust its length, 715 * and toss data from remaining mbufs on chain. 716 */ 717 m = mp; 718 if (m->m_flags & M_PKTHDR) 719 m->m_pkthdr.len = count; 720 for (; m; m = m->m_next) { 721 if (m->m_len >= count) { 722 m->m_len = count; 723 if (m->m_next != NULL) { 724 m_freem(m->m_next); 725 m->m_next = NULL; 726 } 727 break; 728 } 729 count -= m->m_len; 730 } 731 } 732 } 733 734 /* 735 * Rearange an mbuf chain so that len bytes are contiguous 736 * and in the data area of an mbuf (so that mtod will work 737 * for a structure of size len). Returns the resulting 738 * mbuf chain on success, frees it and returns null on failure. 739 * If there is room, it will add up to max_protohdr-len extra bytes to the 740 * contiguous region in an attempt to avoid being called next time. 741 */ 742 struct mbuf * 743 m_pullup(struct mbuf *n, int len) 744 { 745 struct mbuf *m; 746 int count; 747 int space; 748 749 /* 750 * If first mbuf has no cluster, and has room for len bytes 751 * without shifting current data, pullup into it, 752 * otherwise allocate a new mbuf to prepend to the chain. 753 */ 754 if ((n->m_flags & M_EXT) == 0 && 755 n->m_data + len < &n->m_dat[MLEN] && n->m_next) { 756 if (n->m_len >= len) 757 return (n); 758 m = n; 759 n = n->m_next; 760 len -= m->m_len; 761 } else { 762 if (len > MHLEN) 763 goto bad; 764 m = m_get(M_NOWAIT, n->m_type); 765 if (m == NULL) 766 goto bad; 767 if (n->m_flags & M_PKTHDR) 768 m_move_pkthdr(m, n); 769 } 770 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 771 do { 772 count = min(min(max(len, max_protohdr), space), n->m_len); 773 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 774 (u_int)count); 775 len -= count; 776 m->m_len += count; 777 n->m_len -= count; 778 space -= count; 779 if (n->m_len) 780 n->m_data += count; 781 else 782 n = m_free(n); 783 } while (len > 0 && n); 784 if (len > 0) { 785 (void) m_free(m); 786 goto bad; 787 } 788 m->m_next = n; 789 return (m); 790 bad: 791 m_freem(n); 792 return (NULL); 793 } 794 795 /* 796 * Like m_pullup(), except a new mbuf is always allocated, and we allow 797 * the amount of empty space before the data in the new mbuf to be specified 798 * (in the event that the caller expects to prepend later). 799 */ 800 struct mbuf * 801 m_copyup(struct mbuf *n, int len, int dstoff) 802 { 803 struct mbuf *m; 804 int count, space; 805 806 if (len > (MHLEN - dstoff)) 807 goto bad; 808 m = m_get(M_NOWAIT, n->m_type); 809 if (m == NULL) 810 goto bad; 811 if (n->m_flags & M_PKTHDR) 812 m_move_pkthdr(m, n); 813 m->m_data += dstoff; 814 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 815 do { 816 count = min(min(max(len, max_protohdr), space), n->m_len); 817 memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t), 818 (unsigned)count); 819 len -= count; 820 m->m_len += count; 821 n->m_len -= count; 822 space -= count; 823 if (n->m_len) 824 n->m_data += count; 825 else 826 n = m_free(n); 827 } while (len > 0 && n); 828 if (len > 0) { 829 (void) m_free(m); 830 goto bad; 831 } 832 m->m_next = n; 833 return (m); 834 bad: 835 m_freem(n); 836 return (NULL); 837 } 838 839 /* 840 * Partition an mbuf chain in two pieces, returning the tail -- 841 * all but the first len0 bytes. In case of failure, it returns NULL and 842 * attempts to restore the chain to its original state. 843 * 844 * Note that the resulting mbufs might be read-only, because the new 845 * mbuf can end up sharing an mbuf cluster with the original mbuf if 846 * the "breaking point" happens to lie within a cluster mbuf. Use the 847 * M_WRITABLE() macro to check for this case. 848 */ 849 struct mbuf * 850 m_split(struct mbuf *m0, int len0, int wait) 851 { 852 struct mbuf *m, *n; 853 u_int len = len0, remain; 854 855 MBUF_CHECKSLEEP(wait); 856 for (m = m0; m && len > m->m_len; m = m->m_next) 857 len -= m->m_len; 858 if (m == NULL) 859 return (NULL); 860 remain = m->m_len - len; 861 if (m0->m_flags & M_PKTHDR && remain == 0) { 862 n = m_gethdr(wait, m0->m_type); 863 if (n == NULL) 864 return (NULL); 865 n->m_next = m->m_next; 866 m->m_next = NULL; 867 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; 868 n->m_pkthdr.len = m0->m_pkthdr.len - len0; 869 m0->m_pkthdr.len = len0; 870 return (n); 871 } else if (m0->m_flags & M_PKTHDR) { 872 n = m_gethdr(wait, m0->m_type); 873 if (n == NULL) 874 return (NULL); 875 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; 876 n->m_pkthdr.len = m0->m_pkthdr.len - len0; 877 m0->m_pkthdr.len = len0; 878 if (m->m_flags & M_EXT) 879 goto extpacket; 880 if (remain > MHLEN) { 881 /* m can't be the lead packet */ 882 M_ALIGN(n, 0); 883 n->m_next = m_split(m, len, wait); 884 if (n->m_next == NULL) { 885 (void) m_free(n); 886 return (NULL); 887 } else { 888 n->m_len = 0; 889 return (n); 890 } 891 } else 892 M_ALIGN(n, remain); 893 } else if (remain == 0) { 894 n = m->m_next; 895 m->m_next = NULL; 896 return (n); 897 } else { 898 n = m_get(wait, m->m_type); 899 if (n == NULL) 900 return (NULL); 901 M_ALIGN(n, remain); 902 } 903 extpacket: 904 if (m->m_flags & M_EXT) { 905 n->m_data = m->m_data + len; 906 mb_dupcl(n, m); 907 } else { 908 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain); 909 } 910 n->m_len = remain; 911 m->m_len = len; 912 n->m_next = m->m_next; 913 m->m_next = NULL; 914 return (n); 915 } 916 /* 917 * Routine to copy from device local memory into mbufs. 918 * Note that `off' argument is offset into first mbuf of target chain from 919 * which to begin copying the data to. 920 */ 921 struct mbuf * 922 m_devget(char *buf, int totlen, int off, struct ifnet *ifp, 923 void (*copy)(char *from, caddr_t to, u_int len)) 924 { 925 struct mbuf *m; 926 struct mbuf *top = NULL, **mp = ⊤ 927 int len; 928 929 if (off < 0 || off > MHLEN) 930 return (NULL); 931 932 while (totlen > 0) { 933 if (top == NULL) { /* First one, must be PKTHDR */ 934 if (totlen + off >= MINCLSIZE) { 935 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR); 936 len = MCLBYTES; 937 } else { 938 m = m_gethdr(M_NOWAIT, MT_DATA); 939 len = MHLEN; 940 941 /* Place initial small packet/header at end of mbuf */ 942 if (m && totlen + off + max_linkhdr <= MLEN) { 943 m->m_data += max_linkhdr; 944 len -= max_linkhdr; 945 } 946 } 947 if (m == NULL) 948 return NULL; 949 m->m_pkthdr.rcvif = ifp; 950 m->m_pkthdr.len = totlen; 951 } else { 952 if (totlen + off >= MINCLSIZE) { 953 m = m_getcl(M_NOWAIT, MT_DATA, 0); 954 len = MCLBYTES; 955 } else { 956 m = m_get(M_NOWAIT, MT_DATA); 957 len = MLEN; 958 } 959 if (m == NULL) { 960 m_freem(top); 961 return NULL; 962 } 963 } 964 if (off) { 965 m->m_data += off; 966 len -= off; 967 off = 0; 968 } 969 m->m_len = len = min(totlen, len); 970 if (copy) 971 copy(buf, mtod(m, caddr_t), (u_int)len); 972 else 973 bcopy(buf, mtod(m, caddr_t), (u_int)len); 974 buf += len; 975 *mp = m; 976 mp = &m->m_next; 977 totlen -= len; 978 } 979 return (top); 980 } 981 982 /* 983 * Copy data from a buffer back into the indicated mbuf chain, 984 * starting "off" bytes from the beginning, extending the mbuf 985 * chain if necessary. 986 */ 987 void 988 m_copyback(struct mbuf *m0, int off, int len, c_caddr_t cp) 989 { 990 int mlen; 991 struct mbuf *m = m0, *n; 992 int totlen = 0; 993 994 if (m0 == NULL) 995 return; 996 while (off > (mlen = m->m_len)) { 997 off -= mlen; 998 totlen += mlen; 999 if (m->m_next == NULL) { 1000 n = m_get(M_NOWAIT, m->m_type); 1001 if (n == NULL) 1002 goto out; 1003 bzero(mtod(n, caddr_t), MLEN); 1004 n->m_len = min(MLEN, len + off); 1005 m->m_next = n; 1006 } 1007 m = m->m_next; 1008 } 1009 while (len > 0) { 1010 if (m->m_next == NULL && (len > m->m_len - off)) { 1011 m->m_len += min(len - (m->m_len - off), 1012 M_TRAILINGSPACE(m)); 1013 } 1014 mlen = min (m->m_len - off, len); 1015 bcopy(cp, off + mtod(m, caddr_t), (u_int)mlen); 1016 cp += mlen; 1017 len -= mlen; 1018 mlen += off; 1019 off = 0; 1020 totlen += mlen; 1021 if (len == 0) 1022 break; 1023 if (m->m_next == NULL) { 1024 n = m_get(M_NOWAIT, m->m_type); 1025 if (n == NULL) 1026 break; 1027 n->m_len = min(MLEN, len); 1028 m->m_next = n; 1029 } 1030 m = m->m_next; 1031 } 1032 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) 1033 m->m_pkthdr.len = totlen; 1034 } 1035 1036 /* 1037 * Append the specified data to the indicated mbuf chain, 1038 * Extend the mbuf chain if the new data does not fit in 1039 * existing space. 1040 * 1041 * Return 1 if able to complete the job; otherwise 0. 1042 */ 1043 int 1044 m_append(struct mbuf *m0, int len, c_caddr_t cp) 1045 { 1046 struct mbuf *m, *n; 1047 int remainder, space; 1048 1049 for (m = m0; m->m_next != NULL; m = m->m_next) 1050 ; 1051 remainder = len; 1052 space = M_TRAILINGSPACE(m); 1053 if (space > 0) { 1054 /* 1055 * Copy into available space. 1056 */ 1057 if (space > remainder) 1058 space = remainder; 1059 bcopy(cp, mtod(m, caddr_t) + m->m_len, space); 1060 m->m_len += space; 1061 cp += space, remainder -= space; 1062 } 1063 while (remainder > 0) { 1064 /* 1065 * Allocate a new mbuf; could check space 1066 * and allocate a cluster instead. 1067 */ 1068 n = m_get(M_NOWAIT, m->m_type); 1069 if (n == NULL) 1070 break; 1071 n->m_len = min(MLEN, remainder); 1072 bcopy(cp, mtod(n, caddr_t), n->m_len); 1073 cp += n->m_len, remainder -= n->m_len; 1074 m->m_next = n; 1075 m = n; 1076 } 1077 if (m0->m_flags & M_PKTHDR) 1078 m0->m_pkthdr.len += len - remainder; 1079 return (remainder == 0); 1080 } 1081 1082 /* 1083 * Apply function f to the data in an mbuf chain starting "off" bytes from 1084 * the beginning, continuing for "len" bytes. 1085 */ 1086 int 1087 m_apply(struct mbuf *m, int off, int len, 1088 int (*f)(void *, void *, u_int), void *arg) 1089 { 1090 u_int count; 1091 int rval; 1092 1093 KASSERT(off >= 0, ("m_apply, negative off %d", off)); 1094 KASSERT(len >= 0, ("m_apply, negative len %d", len)); 1095 while (off > 0) { 1096 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain")); 1097 if (off < m->m_len) 1098 break; 1099 off -= m->m_len; 1100 m = m->m_next; 1101 } 1102 while (len > 0) { 1103 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain")); 1104 count = min(m->m_len - off, len); 1105 rval = (*f)(arg, mtod(m, caddr_t) + off, count); 1106 if (rval) 1107 return (rval); 1108 len -= count; 1109 off = 0; 1110 m = m->m_next; 1111 } 1112 return (0); 1113 } 1114 1115 /* 1116 * Return a pointer to mbuf/offset of location in mbuf chain. 1117 */ 1118 struct mbuf * 1119 m_getptr(struct mbuf *m, int loc, int *off) 1120 { 1121 1122 while (loc >= 0) { 1123 /* Normal end of search. */ 1124 if (m->m_len > loc) { 1125 *off = loc; 1126 return (m); 1127 } else { 1128 loc -= m->m_len; 1129 if (m->m_next == NULL) { 1130 if (loc == 0) { 1131 /* Point at the end of valid data. */ 1132 *off = m->m_len; 1133 return (m); 1134 } 1135 return (NULL); 1136 } 1137 m = m->m_next; 1138 } 1139 } 1140 return (NULL); 1141 } 1142 1143 void 1144 m_print(const struct mbuf *m, int maxlen) 1145 { 1146 int len; 1147 int pdata; 1148 const struct mbuf *m2; 1149 1150 if (m == NULL) { 1151 printf("mbuf: %p\n", m); 1152 return; 1153 } 1154 1155 if (m->m_flags & M_PKTHDR) 1156 len = m->m_pkthdr.len; 1157 else 1158 len = -1; 1159 m2 = m; 1160 while (m2 != NULL && (len == -1 || len)) { 1161 pdata = m2->m_len; 1162 if (maxlen != -1 && pdata > maxlen) 1163 pdata = maxlen; 1164 printf("mbuf: %p len: %d, next: %p, %b%s", m2, m2->m_len, 1165 m2->m_next, m2->m_flags, "\20\20freelist\17skipfw" 1166 "\11proto5\10proto4\7proto3\6proto2\5proto1\4rdonly" 1167 "\3eor\2pkthdr\1ext", pdata ? "" : "\n"); 1168 if (pdata) 1169 printf(", %*D\n", pdata, (u_char *)m2->m_data, "-"); 1170 if (len != -1) 1171 len -= m2->m_len; 1172 m2 = m2->m_next; 1173 } 1174 if (len > 0) 1175 printf("%d bytes unaccounted for.\n", len); 1176 return; 1177 } 1178 1179 u_int 1180 m_fixhdr(struct mbuf *m0) 1181 { 1182 u_int len; 1183 1184 len = m_length(m0, NULL); 1185 m0->m_pkthdr.len = len; 1186 return (len); 1187 } 1188 1189 u_int 1190 m_length(struct mbuf *m0, struct mbuf **last) 1191 { 1192 struct mbuf *m; 1193 u_int len; 1194 1195 len = 0; 1196 for (m = m0; m != NULL; m = m->m_next) { 1197 len += m->m_len; 1198 if (m->m_next == NULL) 1199 break; 1200 } 1201 if (last != NULL) 1202 *last = m; 1203 return (len); 1204 } 1205 1206 /* 1207 * Defragment a mbuf chain, returning the shortest possible 1208 * chain of mbufs and clusters. If allocation fails and 1209 * this cannot be completed, NULL will be returned, but 1210 * the passed in chain will be unchanged. Upon success, 1211 * the original chain will be freed, and the new chain 1212 * will be returned. 1213 * 1214 * If a non-packet header is passed in, the original 1215 * mbuf (chain?) will be returned unharmed. 1216 */ 1217 struct mbuf * 1218 m_defrag(struct mbuf *m0, int how) 1219 { 1220 struct mbuf *m_new = NULL, *m_final = NULL; 1221 int progress = 0, length; 1222 1223 MBUF_CHECKSLEEP(how); 1224 if (!(m0->m_flags & M_PKTHDR)) 1225 return (m0); 1226 1227 m_fixhdr(m0); /* Needed sanity check */ 1228 1229 #ifdef MBUF_STRESS_TEST 1230 if (m_defragrandomfailures) { 1231 int temp = arc4random() & 0xff; 1232 if (temp == 0xba) 1233 goto nospace; 1234 } 1235 #endif 1236 1237 if (m0->m_pkthdr.len > MHLEN) 1238 m_final = m_getcl(how, MT_DATA, M_PKTHDR); 1239 else 1240 m_final = m_gethdr(how, MT_DATA); 1241 1242 if (m_final == NULL) 1243 goto nospace; 1244 1245 if (m_dup_pkthdr(m_final, m0, how) == 0) 1246 goto nospace; 1247 1248 m_new = m_final; 1249 1250 while (progress < m0->m_pkthdr.len) { 1251 length = m0->m_pkthdr.len - progress; 1252 if (length > MCLBYTES) 1253 length = MCLBYTES; 1254 1255 if (m_new == NULL) { 1256 if (length > MLEN) 1257 m_new = m_getcl(how, MT_DATA, 0); 1258 else 1259 m_new = m_get(how, MT_DATA); 1260 if (m_new == NULL) 1261 goto nospace; 1262 } 1263 1264 m_copydata(m0, progress, length, mtod(m_new, caddr_t)); 1265 progress += length; 1266 m_new->m_len = length; 1267 if (m_new != m_final) 1268 m_cat(m_final, m_new); 1269 m_new = NULL; 1270 } 1271 #ifdef MBUF_STRESS_TEST 1272 if (m0->m_next == NULL) 1273 m_defraguseless++; 1274 #endif 1275 m_freem(m0); 1276 m0 = m_final; 1277 #ifdef MBUF_STRESS_TEST 1278 m_defragpackets++; 1279 m_defragbytes += m0->m_pkthdr.len; 1280 #endif 1281 return (m0); 1282 nospace: 1283 #ifdef MBUF_STRESS_TEST 1284 m_defragfailure++; 1285 #endif 1286 if (m_final) 1287 m_freem(m_final); 1288 return (NULL); 1289 } 1290 1291 /* 1292 * Defragment an mbuf chain, returning at most maxfrags separate 1293 * mbufs+clusters. If this is not possible NULL is returned and 1294 * the original mbuf chain is left in it's present (potentially 1295 * modified) state. We use two techniques: collapsing consecutive 1296 * mbufs and replacing consecutive mbufs by a cluster. 1297 * 1298 * NB: this should really be named m_defrag but that name is taken 1299 */ 1300 struct mbuf * 1301 m_collapse(struct mbuf *m0, int how, int maxfrags) 1302 { 1303 struct mbuf *m, *n, *n2, **prev; 1304 u_int curfrags; 1305 1306 /* 1307 * Calculate the current number of frags. 1308 */ 1309 curfrags = 0; 1310 for (m = m0; m != NULL; m = m->m_next) 1311 curfrags++; 1312 /* 1313 * First, try to collapse mbufs. Note that we always collapse 1314 * towards the front so we don't need to deal with moving the 1315 * pkthdr. This may be suboptimal if the first mbuf has much 1316 * less data than the following. 1317 */ 1318 m = m0; 1319 again: 1320 for (;;) { 1321 n = m->m_next; 1322 if (n == NULL) 1323 break; 1324 if (M_WRITABLE(m) && 1325 n->m_len < M_TRAILINGSPACE(m)) { 1326 bcopy(mtod(n, void *), mtod(m, char *) + m->m_len, 1327 n->m_len); 1328 m->m_len += n->m_len; 1329 m->m_next = n->m_next; 1330 m_free(n); 1331 if (--curfrags <= maxfrags) 1332 return m0; 1333 } else 1334 m = n; 1335 } 1336 KASSERT(maxfrags > 1, 1337 ("maxfrags %u, but normal collapse failed", maxfrags)); 1338 /* 1339 * Collapse consecutive mbufs to a cluster. 1340 */ 1341 prev = &m0->m_next; /* NB: not the first mbuf */ 1342 while ((n = *prev) != NULL) { 1343 if ((n2 = n->m_next) != NULL && 1344 n->m_len + n2->m_len < MCLBYTES) { 1345 m = m_getcl(how, MT_DATA, 0); 1346 if (m == NULL) 1347 goto bad; 1348 bcopy(mtod(n, void *), mtod(m, void *), n->m_len); 1349 bcopy(mtod(n2, void *), mtod(m, char *) + n->m_len, 1350 n2->m_len); 1351 m->m_len = n->m_len + n2->m_len; 1352 m->m_next = n2->m_next; 1353 *prev = m; 1354 m_free(n); 1355 m_free(n2); 1356 if (--curfrags <= maxfrags) /* +1 cl -2 mbufs */ 1357 return m0; 1358 /* 1359 * Still not there, try the normal collapse 1360 * again before we allocate another cluster. 1361 */ 1362 goto again; 1363 } 1364 prev = &n->m_next; 1365 } 1366 /* 1367 * No place where we can collapse to a cluster; punt. 1368 * This can occur if, for example, you request 2 frags 1369 * but the packet requires that both be clusters (we 1370 * never reallocate the first mbuf to avoid moving the 1371 * packet header). 1372 */ 1373 bad: 1374 return NULL; 1375 } 1376 1377 #ifdef MBUF_STRESS_TEST 1378 1379 /* 1380 * Fragment an mbuf chain. There's no reason you'd ever want to do 1381 * this in normal usage, but it's great for stress testing various 1382 * mbuf consumers. 1383 * 1384 * If fragmentation is not possible, the original chain will be 1385 * returned. 1386 * 1387 * Possible length values: 1388 * 0 no fragmentation will occur 1389 * > 0 each fragment will be of the specified length 1390 * -1 each fragment will be the same random value in length 1391 * -2 each fragment's length will be entirely random 1392 * (Random values range from 1 to 256) 1393 */ 1394 struct mbuf * 1395 m_fragment(struct mbuf *m0, int how, int length) 1396 { 1397 struct mbuf *m_new = NULL, *m_final = NULL; 1398 int progress = 0; 1399 1400 if (!(m0->m_flags & M_PKTHDR)) 1401 return (m0); 1402 1403 if ((length == 0) || (length < -2)) 1404 return (m0); 1405 1406 m_fixhdr(m0); /* Needed sanity check */ 1407 1408 m_final = m_getcl(how, MT_DATA, M_PKTHDR); 1409 1410 if (m_final == NULL) 1411 goto nospace; 1412 1413 if (m_dup_pkthdr(m_final, m0, how) == 0) 1414 goto nospace; 1415 1416 m_new = m_final; 1417 1418 if (length == -1) 1419 length = 1 + (arc4random() & 255); 1420 1421 while (progress < m0->m_pkthdr.len) { 1422 int fraglen; 1423 1424 if (length > 0) 1425 fraglen = length; 1426 else 1427 fraglen = 1 + (arc4random() & 255); 1428 if (fraglen > m0->m_pkthdr.len - progress) 1429 fraglen = m0->m_pkthdr.len - progress; 1430 1431 if (fraglen > MCLBYTES) 1432 fraglen = MCLBYTES; 1433 1434 if (m_new == NULL) { 1435 m_new = m_getcl(how, MT_DATA, 0); 1436 if (m_new == NULL) 1437 goto nospace; 1438 } 1439 1440 m_copydata(m0, progress, fraglen, mtod(m_new, caddr_t)); 1441 progress += fraglen; 1442 m_new->m_len = fraglen; 1443 if (m_new != m_final) 1444 m_cat(m_final, m_new); 1445 m_new = NULL; 1446 } 1447 m_freem(m0); 1448 m0 = m_final; 1449 return (m0); 1450 nospace: 1451 if (m_final) 1452 m_freem(m_final); 1453 /* Return the original chain on failure */ 1454 return (m0); 1455 } 1456 1457 #endif 1458 1459 /* 1460 * Copy the contents of uio into a properly sized mbuf chain. 1461 */ 1462 struct mbuf * 1463 m_uiotombuf(struct uio *uio, int how, int len, int align, int flags) 1464 { 1465 struct mbuf *m, *mb; 1466 int error, length; 1467 ssize_t total; 1468 int progress = 0; 1469 1470 /* 1471 * len can be zero or an arbitrary large value bound by 1472 * the total data supplied by the uio. 1473 */ 1474 if (len > 0) 1475 total = min(uio->uio_resid, len); 1476 else 1477 total = uio->uio_resid; 1478 1479 /* 1480 * The smallest unit returned by m_getm2() is a single mbuf 1481 * with pkthdr. We can't align past it. 1482 */ 1483 if (align >= MHLEN) 1484 return (NULL); 1485 1486 /* 1487 * Give us the full allocation or nothing. 1488 * If len is zero return the smallest empty mbuf. 1489 */ 1490 m = m_getm2(NULL, max(total + align, 1), how, MT_DATA, flags); 1491 if (m == NULL) 1492 return (NULL); 1493 m->m_data += align; 1494 1495 /* Fill all mbufs with uio data and update header information. */ 1496 for (mb = m; mb != NULL; mb = mb->m_next) { 1497 length = min(M_TRAILINGSPACE(mb), total - progress); 1498 1499 error = uiomove(mtod(mb, void *), length, uio); 1500 if (error) { 1501 m_freem(m); 1502 return (NULL); 1503 } 1504 1505 mb->m_len = length; 1506 progress += length; 1507 if (flags & M_PKTHDR) 1508 m->m_pkthdr.len += length; 1509 } 1510 KASSERT(progress == total, ("%s: progress != total", __func__)); 1511 1512 return (m); 1513 } 1514 1515 /* 1516 * Copy an mbuf chain into a uio limited by len if set. 1517 */ 1518 int 1519 m_mbuftouio(struct uio *uio, struct mbuf *m, int len) 1520 { 1521 int error, length, total; 1522 int progress = 0; 1523 1524 if (len > 0) 1525 total = min(uio->uio_resid, len); 1526 else 1527 total = uio->uio_resid; 1528 1529 /* Fill the uio with data from the mbufs. */ 1530 for (; m != NULL; m = m->m_next) { 1531 length = min(m->m_len, total - progress); 1532 1533 error = uiomove(mtod(m, void *), length, uio); 1534 if (error) 1535 return (error); 1536 1537 progress += length; 1538 } 1539 1540 return (0); 1541 } 1542 1543 /* 1544 * Create a writable copy of the mbuf chain. While doing this 1545 * we compact the chain with a goal of producing a chain with 1546 * at most two mbufs. The second mbuf in this chain is likely 1547 * to be a cluster. The primary purpose of this work is to create 1548 * a writable packet for encryption, compression, etc. The 1549 * secondary goal is to linearize the data so the data can be 1550 * passed to crypto hardware in the most efficient manner possible. 1551 */ 1552 struct mbuf * 1553 m_unshare(struct mbuf *m0, int how) 1554 { 1555 struct mbuf *m, *mprev; 1556 struct mbuf *n, *mfirst, *mlast; 1557 int len, off; 1558 1559 mprev = NULL; 1560 for (m = m0; m != NULL; m = mprev->m_next) { 1561 /* 1562 * Regular mbufs are ignored unless there's a cluster 1563 * in front of it that we can use to coalesce. We do 1564 * the latter mainly so later clusters can be coalesced 1565 * also w/o having to handle them specially (i.e. convert 1566 * mbuf+cluster -> cluster). This optimization is heavily 1567 * influenced by the assumption that we're running over 1568 * Ethernet where MCLBYTES is large enough that the max 1569 * packet size will permit lots of coalescing into a 1570 * single cluster. This in turn permits efficient 1571 * crypto operations, especially when using hardware. 1572 */ 1573 if ((m->m_flags & M_EXT) == 0) { 1574 if (mprev && (mprev->m_flags & M_EXT) && 1575 m->m_len <= M_TRAILINGSPACE(mprev)) { 1576 /* XXX: this ignores mbuf types */ 1577 memcpy(mtod(mprev, caddr_t) + mprev->m_len, 1578 mtod(m, caddr_t), m->m_len); 1579 mprev->m_len += m->m_len; 1580 mprev->m_next = m->m_next; /* unlink from chain */ 1581 m_free(m); /* reclaim mbuf */ 1582 #if 0 1583 newipsecstat.ips_mbcoalesced++; 1584 #endif 1585 } else { 1586 mprev = m; 1587 } 1588 continue; 1589 } 1590 /* 1591 * Writable mbufs are left alone (for now). 1592 */ 1593 if (M_WRITABLE(m)) { 1594 mprev = m; 1595 continue; 1596 } 1597 1598 /* 1599 * Not writable, replace with a copy or coalesce with 1600 * the previous mbuf if possible (since we have to copy 1601 * it anyway, we try to reduce the number of mbufs and 1602 * clusters so that future work is easier). 1603 */ 1604 KASSERT(m->m_flags & M_EXT, ("m_flags 0x%x", m->m_flags)); 1605 /* NB: we only coalesce into a cluster or larger */ 1606 if (mprev != NULL && (mprev->m_flags & M_EXT) && 1607 m->m_len <= M_TRAILINGSPACE(mprev)) { 1608 /* XXX: this ignores mbuf types */ 1609 memcpy(mtod(mprev, caddr_t) + mprev->m_len, 1610 mtod(m, caddr_t), m->m_len); 1611 mprev->m_len += m->m_len; 1612 mprev->m_next = m->m_next; /* unlink from chain */ 1613 m_free(m); /* reclaim mbuf */ 1614 #if 0 1615 newipsecstat.ips_clcoalesced++; 1616 #endif 1617 continue; 1618 } 1619 1620 /* 1621 * Allocate new space to hold the copy and copy the data. 1622 * We deal with jumbo mbufs (i.e. m_len > MCLBYTES) by 1623 * splitting them into clusters. We could just malloc a 1624 * buffer and make it external but too many device drivers 1625 * don't know how to break up the non-contiguous memory when 1626 * doing DMA. 1627 */ 1628 n = m_getcl(how, m->m_type, m->m_flags); 1629 if (n == NULL) { 1630 m_freem(m0); 1631 return (NULL); 1632 } 1633 if (m->m_flags & M_PKTHDR) { 1634 KASSERT(mprev == NULL, ("%s: m0 %p, m %p has M_PKTHDR", 1635 __func__, m0, m)); 1636 m_move_pkthdr(n, m); 1637 } 1638 len = m->m_len; 1639 off = 0; 1640 mfirst = n; 1641 mlast = NULL; 1642 for (;;) { 1643 int cc = min(len, MCLBYTES); 1644 memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, cc); 1645 n->m_len = cc; 1646 if (mlast != NULL) 1647 mlast->m_next = n; 1648 mlast = n; 1649 #if 0 1650 newipsecstat.ips_clcopied++; 1651 #endif 1652 1653 len -= cc; 1654 if (len <= 0) 1655 break; 1656 off += cc; 1657 1658 n = m_getcl(how, m->m_type, m->m_flags); 1659 if (n == NULL) { 1660 m_freem(mfirst); 1661 m_freem(m0); 1662 return (NULL); 1663 } 1664 } 1665 n->m_next = m->m_next; 1666 if (mprev == NULL) 1667 m0 = mfirst; /* new head of chain */ 1668 else 1669 mprev->m_next = mfirst; /* replace old mbuf */ 1670 m_free(m); /* release old mbuf */ 1671 mprev = mfirst; 1672 } 1673 return (m0); 1674 } 1675 1676 #ifdef MBUF_PROFILING 1677 1678 #define MP_BUCKETS 32 /* don't just change this as things may overflow.*/ 1679 struct mbufprofile { 1680 uintmax_t wasted[MP_BUCKETS]; 1681 uintmax_t used[MP_BUCKETS]; 1682 uintmax_t segments[MP_BUCKETS]; 1683 } mbprof; 1684 1685 #define MP_MAXDIGITS 21 /* strlen("16,000,000,000,000,000,000") == 21 */ 1686 #define MP_NUMLINES 6 1687 #define MP_NUMSPERLINE 16 1688 #define MP_EXTRABYTES 64 /* > strlen("used:\nwasted:\nsegments:\n") */ 1689 /* work out max space needed and add a bit of spare space too */ 1690 #define MP_MAXLINE ((MP_MAXDIGITS+1) * MP_NUMSPERLINE) 1691 #define MP_BUFSIZE ((MP_MAXLINE * MP_NUMLINES) + 1 + MP_EXTRABYTES) 1692 1693 char mbprofbuf[MP_BUFSIZE]; 1694 1695 void 1696 m_profile(struct mbuf *m) 1697 { 1698 int segments = 0; 1699 int used = 0; 1700 int wasted = 0; 1701 1702 while (m) { 1703 segments++; 1704 used += m->m_len; 1705 if (m->m_flags & M_EXT) { 1706 wasted += MHLEN - sizeof(m->m_ext) + 1707 m->m_ext.ext_size - m->m_len; 1708 } else { 1709 if (m->m_flags & M_PKTHDR) 1710 wasted += MHLEN - m->m_len; 1711 else 1712 wasted += MLEN - m->m_len; 1713 } 1714 m = m->m_next; 1715 } 1716 /* be paranoid.. it helps */ 1717 if (segments > MP_BUCKETS - 1) 1718 segments = MP_BUCKETS - 1; 1719 if (used > 100000) 1720 used = 100000; 1721 if (wasted > 100000) 1722 wasted = 100000; 1723 /* store in the appropriate bucket */ 1724 /* don't bother locking. if it's slightly off, so what? */ 1725 mbprof.segments[segments]++; 1726 mbprof.used[fls(used)]++; 1727 mbprof.wasted[fls(wasted)]++; 1728 } 1729 1730 static void 1731 mbprof_textify(void) 1732 { 1733 int offset; 1734 char *c; 1735 uint64_t *p; 1736 1737 p = &mbprof.wasted[0]; 1738 c = mbprofbuf; 1739 offset = snprintf(c, MP_MAXLINE + 10, 1740 "wasted:\n" 1741 "%ju %ju %ju %ju %ju %ju %ju %ju " 1742 "%ju %ju %ju %ju %ju %ju %ju %ju\n", 1743 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], 1744 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); 1745 #ifdef BIG_ARRAY 1746 p = &mbprof.wasted[16]; 1747 c += offset; 1748 offset = snprintf(c, MP_MAXLINE, 1749 "%ju %ju %ju %ju %ju %ju %ju %ju " 1750 "%ju %ju %ju %ju %ju %ju %ju %ju\n", 1751 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], 1752 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); 1753 #endif 1754 p = &mbprof.used[0]; 1755 c += offset; 1756 offset = snprintf(c, MP_MAXLINE + 10, 1757 "used:\n" 1758 "%ju %ju %ju %ju %ju %ju %ju %ju " 1759 "%ju %ju %ju %ju %ju %ju %ju %ju\n", 1760 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], 1761 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); 1762 #ifdef BIG_ARRAY 1763 p = &mbprof.used[16]; 1764 c += offset; 1765 offset = snprintf(c, MP_MAXLINE, 1766 "%ju %ju %ju %ju %ju %ju %ju %ju " 1767 "%ju %ju %ju %ju %ju %ju %ju %ju\n", 1768 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], 1769 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); 1770 #endif 1771 p = &mbprof.segments[0]; 1772 c += offset; 1773 offset = snprintf(c, MP_MAXLINE + 10, 1774 "segments:\n" 1775 "%ju %ju %ju %ju %ju %ju %ju %ju " 1776 "%ju %ju %ju %ju %ju %ju %ju %ju\n", 1777 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], 1778 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); 1779 #ifdef BIG_ARRAY 1780 p = &mbprof.segments[16]; 1781 c += offset; 1782 offset = snprintf(c, MP_MAXLINE, 1783 "%ju %ju %ju %ju %ju %ju %ju %ju " 1784 "%ju %ju %ju %ju %ju %ju %ju %jju", 1785 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], 1786 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); 1787 #endif 1788 } 1789 1790 static int 1791 mbprof_handler(SYSCTL_HANDLER_ARGS) 1792 { 1793 int error; 1794 1795 mbprof_textify(); 1796 error = SYSCTL_OUT(req, mbprofbuf, strlen(mbprofbuf) + 1); 1797 return (error); 1798 } 1799 1800 static int 1801 mbprof_clr_handler(SYSCTL_HANDLER_ARGS) 1802 { 1803 int clear, error; 1804 1805 clear = 0; 1806 error = sysctl_handle_int(oidp, &clear, 0, req); 1807 if (error || !req->newptr) 1808 return (error); 1809 1810 if (clear) { 1811 bzero(&mbprof, sizeof(mbprof)); 1812 } 1813 1814 return (error); 1815 } 1816 1817 1818 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofile, CTLTYPE_STRING|CTLFLAG_RD, 1819 NULL, 0, mbprof_handler, "A", "mbuf profiling statistics"); 1820 1821 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofileclr, CTLTYPE_INT|CTLFLAG_RW, 1822 NULL, 0, mbprof_clr_handler, "I", "clear mbuf profiling statistics"); 1823 #endif 1824 1825