Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/uipc_mbuf.c
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1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1988, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #include "opt_param.h" 38 #include "opt_mbuf_stress_test.h" 39 #include "opt_mbuf_profiling.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/kernel.h> 44 #include <sys/limits.h> 45 #include <sys/lock.h> 46 #include <sys/malloc.h> 47 #include <sys/mbuf.h> 48 #include <sys/sysctl.h> 49 #include <sys/domain.h> 50 #include <sys/protosw.h> 51 #include <sys/uio.h> 52 #include <sys/vmmeter.h> 53 #include <sys/sdt.h> 54 #include <vm/vm.h> 55 #include <vm/vm_pageout.h> 56 #include <vm/vm_page.h> 57 58 SDT_PROBE_DEFINE5_XLATE(sdt, , , m__init, 59 "struct mbuf *", "mbufinfo_t *", 60 "uint32_t", "uint32_t", 61 "uint16_t", "uint16_t", 62 "uint32_t", "uint32_t", 63 "uint32_t", "uint32_t"); 64 65 SDT_PROBE_DEFINE3_XLATE(sdt, , , m__gethdr, 66 "uint32_t", "uint32_t", 67 "uint16_t", "uint16_t", 68 "struct mbuf *", "mbufinfo_t *"); 69 70 SDT_PROBE_DEFINE3_XLATE(sdt, , , m__get, 71 "uint32_t", "uint32_t", 72 "uint16_t", "uint16_t", 73 "struct mbuf *", "mbufinfo_t *"); 74 75 SDT_PROBE_DEFINE4_XLATE(sdt, , , m__getcl, 76 "uint32_t", "uint32_t", 77 "uint16_t", "uint16_t", 78 "uint32_t", "uint32_t", 79 "struct mbuf *", "mbufinfo_t *"); 80 81 SDT_PROBE_DEFINE5_XLATE(sdt, , , m__getjcl, 82 "uint32_t", "uint32_t", 83 "uint16_t", "uint16_t", 84 "uint32_t", "uint32_t", 85 "uint32_t", "uint32_t", 86 "struct mbuf *", "mbufinfo_t *"); 87 88 SDT_PROBE_DEFINE3_XLATE(sdt, , , m__clget, 89 "struct mbuf *", "mbufinfo_t *", 90 "uint32_t", "uint32_t", 91 "uint32_t", "uint32_t"); 92 93 SDT_PROBE_DEFINE4_XLATE(sdt, , , m__cljget, 94 "struct mbuf *", "mbufinfo_t *", 95 "uint32_t", "uint32_t", 96 "uint32_t", "uint32_t", 97 "void*", "void*"); 98 99 SDT_PROBE_DEFINE(sdt, , , m__cljset); 100 101 SDT_PROBE_DEFINE1_XLATE(sdt, , , m__free, 102 "struct mbuf *", "mbufinfo_t *"); 103 104 SDT_PROBE_DEFINE1_XLATE(sdt, , , m__freem, 105 "struct mbuf *", "mbufinfo_t *"); 106 107 #include <security/mac/mac_framework.h> 108 109 int max_linkhdr; 110 int max_protohdr; 111 int max_hdr; 112 int max_datalen; 113 #ifdef MBUF_STRESS_TEST 114 int m_defragpackets; 115 int m_defragbytes; 116 int m_defraguseless; 117 int m_defragfailure; 118 int m_defragrandomfailures; 119 #endif 120 121 /* 122 * sysctl(8) exported objects 123 */ 124 SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RD, 125 &max_linkhdr, 0, "Size of largest link layer header"); 126 SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RD, 127 &max_protohdr, 0, "Size of largest protocol layer header"); 128 SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RD, 129 &max_hdr, 0, "Size of largest link plus protocol header"); 130 SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RD, 131 &max_datalen, 0, "Minimum space left in mbuf after max_hdr"); 132 #ifdef MBUF_STRESS_TEST 133 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD, 134 &m_defragpackets, 0, ""); 135 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD, 136 &m_defragbytes, 0, ""); 137 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD, 138 &m_defraguseless, 0, ""); 139 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD, 140 &m_defragfailure, 0, ""); 141 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW, 142 &m_defragrandomfailures, 0, ""); 143 #endif 144 145 /* 146 * Ensure the correct size of various mbuf parameters. It could be off due 147 * to compiler-induced padding and alignment artifacts. 148 */ 149 CTASSERT(MSIZE - offsetof(struct mbuf, m_dat) == MLEN); 150 CTASSERT(MSIZE - offsetof(struct mbuf, m_pktdat) == MHLEN); 151 152 /* 153 * mbuf data storage should be 64-bit aligned regardless of architectural 154 * pointer size; check this is the case with and without a packet header. 155 */ 156 CTASSERT(offsetof(struct mbuf, m_dat) % 8 == 0); 157 CTASSERT(offsetof(struct mbuf, m_pktdat) % 8 == 0); 158 159 /* 160 * While the specific values here don't matter too much (i.e., +/- a few 161 * words), we do want to ensure that changes to these values are carefully 162 * reasoned about and properly documented. This is especially the case as 163 * network-protocol and device-driver modules encode these layouts, and must 164 * be recompiled if the structures change. Check these values at compile time 165 * against the ones documented in comments in mbuf.h. 166 * 167 * NB: Possibly they should be documented there via #define's and not just 168 * comments. 169 */ 170 #if defined(__LP64__) 171 CTASSERT(offsetof(struct mbuf, m_dat) == 32); 172 CTASSERT(sizeof(struct pkthdr) == 56); 173 CTASSERT(sizeof(struct m_ext) == 160); 174 #else 175 CTASSERT(offsetof(struct mbuf, m_dat) == 24); 176 CTASSERT(sizeof(struct pkthdr) == 48); 177 #if defined(__powerpc__) && defined(BOOKE) 178 /* PowerPC booke has 64-bit physical pointers. */ 179 CTASSERT(sizeof(struct m_ext) == 184); 180 #else 181 CTASSERT(sizeof(struct m_ext) == 180); 182 #endif 183 #endif 184 185 /* 186 * Assert that the queue(3) macros produce code of the same size as an old 187 * plain pointer does. 188 */ 189 #ifdef INVARIANTS 190 static struct mbuf __used m_assertbuf; 191 CTASSERT(sizeof(m_assertbuf.m_slist) == sizeof(m_assertbuf.m_next)); 192 CTASSERT(sizeof(m_assertbuf.m_stailq) == sizeof(m_assertbuf.m_next)); 193 CTASSERT(sizeof(m_assertbuf.m_slistpkt) == sizeof(m_assertbuf.m_nextpkt)); 194 CTASSERT(sizeof(m_assertbuf.m_stailqpkt) == sizeof(m_assertbuf.m_nextpkt)); 195 #endif 196 197 /* 198 * Attach the cluster from *m to *n, set up m_ext in *n 199 * and bump the refcount of the cluster. 200 */ 201 void 202 mb_dupcl(struct mbuf *n, struct mbuf *m) 203 { 204 volatile u_int *refcnt; 205 206 KASSERT(m->m_flags & (M_EXT|M_EXTPG), 207 ("%s: M_EXT|M_EXTPG not set on %p", __func__, m)); 208 KASSERT(!(n->m_flags & (M_EXT|M_EXTPG)), 209 ("%s: M_EXT|M_EXTPG set on %p", __func__, n)); 210 211 /* 212 * Cache access optimization. 213 * 214 * o Regular M_EXT storage doesn't need full copy of m_ext, since 215 * the holder of the 'ext_count' is responsible to carry the free 216 * routine and its arguments. 217 * o M_EXTPG data is split between main part of mbuf and m_ext, the 218 * main part is copied in full, the m_ext part is similar to M_EXT. 219 * o EXT_EXTREF, where 'ext_cnt' doesn't point into mbuf at all, is 220 * special - it needs full copy of m_ext into each mbuf, since any 221 * copy could end up as the last to free. 222 */ 223 if (m->m_flags & M_EXTPG) { 224 bcopy(&m->m_epg_startcopy, &n->m_epg_startcopy, 225 __rangeof(struct mbuf, m_epg_startcopy, m_epg_endcopy)); 226 bcopy(&m->m_ext, &n->m_ext, m_epg_ext_copylen); 227 } else if (m->m_ext.ext_type == EXT_EXTREF) 228 bcopy(&m->m_ext, &n->m_ext, sizeof(struct m_ext)); 229 else 230 bcopy(&m->m_ext, &n->m_ext, m_ext_copylen); 231 232 n->m_flags |= m->m_flags & (M_RDONLY | M_EXT | M_EXTPG); 233 234 /* See if this is the mbuf that holds the embedded refcount. */ 235 if (m->m_ext.ext_flags & EXT_FLAG_EMBREF) { 236 refcnt = n->m_ext.ext_cnt = &m->m_ext.ext_count; 237 n->m_ext.ext_flags &= ~EXT_FLAG_EMBREF; 238 } else { 239 KASSERT(m->m_ext.ext_cnt != NULL, 240 ("%s: no refcounting pointer on %p", __func__, m)); 241 refcnt = m->m_ext.ext_cnt; 242 } 243 244 if (*refcnt == 1) 245 *refcnt += 1; 246 else 247 atomic_add_int(refcnt, 1); 248 } 249 250 void 251 m_demote_pkthdr(struct mbuf *m) 252 { 253 254 M_ASSERTPKTHDR(m); 255 256 m_tag_delete_chain(m, NULL); 257 m->m_flags &= ~M_PKTHDR; 258 bzero(&m->m_pkthdr, sizeof(struct pkthdr)); 259 } 260 261 /* 262 * Clean up mbuf (chain) from any tags and packet headers. 263 * If "all" is set then the first mbuf in the chain will be 264 * cleaned too. 265 */ 266 void 267 m_demote(struct mbuf *m0, int all, int flags) 268 { 269 struct mbuf *m; 270 271 for (m = all ? m0 : m0->m_next; m != NULL; m = m->m_next) { 272 KASSERT(m->m_nextpkt == NULL, ("%s: m_nextpkt in m %p, m0 %p", 273 __func__, m, m0)); 274 if (m->m_flags & M_PKTHDR) 275 m_demote_pkthdr(m); 276 m->m_flags = m->m_flags & (M_EXT | M_RDONLY | M_NOFREE | 277 M_EXTPG | flags); 278 } 279 } 280 281 /* 282 * Sanity checks on mbuf (chain) for use in KASSERT() and general 283 * debugging. 284 * Returns 0 or panics when bad and 1 on all tests passed. 285 * Sanitize, 0 to run M_SANITY_ACTION, 1 to garble things so they 286 * blow up later. 287 */ 288 int 289 m_sanity(struct mbuf *m0, int sanitize) 290 { 291 struct mbuf *m; 292 caddr_t a, b; 293 int pktlen = 0; 294 295 #ifdef INVARIANTS 296 #define M_SANITY_ACTION(s) panic("mbuf %p: " s, m) 297 #else 298 #define M_SANITY_ACTION(s) printf("mbuf %p: " s, m) 299 #endif 300 301 for (m = m0; m != NULL; m = m->m_next) { 302 /* 303 * Basic pointer checks. If any of these fails then some 304 * unrelated kernel memory before or after us is trashed. 305 * No way to recover from that. 306 */ 307 a = M_START(m); 308 b = a + M_SIZE(m); 309 if ((caddr_t)m->m_data < a) 310 M_SANITY_ACTION("m_data outside mbuf data range left"); 311 if ((caddr_t)m->m_data > b) 312 M_SANITY_ACTION("m_data outside mbuf data range right"); 313 if ((caddr_t)m->m_data + m->m_len > b) 314 M_SANITY_ACTION("m_data + m_len exeeds mbuf space"); 315 316 /* m->m_nextpkt may only be set on first mbuf in chain. */ 317 if (m != m0 && m->m_nextpkt != NULL) { 318 if (sanitize) { 319 m_freem(m->m_nextpkt); 320 m->m_nextpkt = (struct mbuf *)0xDEADC0DE; 321 } else 322 M_SANITY_ACTION("m->m_nextpkt on in-chain mbuf"); 323 } 324 325 /* packet length (not mbuf length!) calculation */ 326 if (m0->m_flags & M_PKTHDR) 327 pktlen += m->m_len; 328 329 /* m_tags may only be attached to first mbuf in chain. */ 330 if (m != m0 && m->m_flags & M_PKTHDR && 331 !SLIST_EMPTY(&m->m_pkthdr.tags)) { 332 if (sanitize) { 333 m_tag_delete_chain(m, NULL); 334 /* put in 0xDEADC0DE perhaps? */ 335 } else 336 M_SANITY_ACTION("m_tags on in-chain mbuf"); 337 } 338 339 /* M_PKTHDR may only be set on first mbuf in chain */ 340 if (m != m0 && m->m_flags & M_PKTHDR) { 341 if (sanitize) { 342 bzero(&m->m_pkthdr, sizeof(m->m_pkthdr)); 343 m->m_flags &= ~M_PKTHDR; 344 /* put in 0xDEADCODE and leave hdr flag in */ 345 } else 346 M_SANITY_ACTION("M_PKTHDR on in-chain mbuf"); 347 } 348 } 349 m = m0; 350 if (pktlen && pktlen != m->m_pkthdr.len) { 351 if (sanitize) 352 m->m_pkthdr.len = 0; 353 else 354 M_SANITY_ACTION("m_pkthdr.len != mbuf chain length"); 355 } 356 return 1; 357 358 #undef M_SANITY_ACTION 359 } 360 361 /* 362 * Non-inlined part of m_init(). 363 */ 364 int 365 m_pkthdr_init(struct mbuf *m, int how) 366 { 367 #ifdef MAC 368 int error; 369 #endif 370 m->m_data = m->m_pktdat; 371 bzero(&m->m_pkthdr, sizeof(m->m_pkthdr)); 372 #ifdef NUMA 373 m->m_pkthdr.numa_domain = M_NODOM; 374 #endif 375 #ifdef MAC 376 /* If the label init fails, fail the alloc */ 377 error = mac_mbuf_init(m, how); 378 if (error) 379 return (error); 380 #endif 381 382 return (0); 383 } 384 385 /* 386 * "Move" mbuf pkthdr from "from" to "to". 387 * "from" must have M_PKTHDR set, and "to" must be empty. 388 */ 389 void 390 m_move_pkthdr(struct mbuf *to, struct mbuf *from) 391 { 392 393 #if 0 394 /* see below for why these are not enabled */ 395 M_ASSERTPKTHDR(to); 396 /* Note: with MAC, this may not be a good assertion. */ 397 KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), 398 ("m_move_pkthdr: to has tags")); 399 #endif 400 #ifdef MAC 401 /* 402 * XXXMAC: It could be this should also occur for non-MAC? 403 */ 404 if (to->m_flags & M_PKTHDR) 405 m_tag_delete_chain(to, NULL); 406 #endif 407 to->m_flags = (from->m_flags & M_COPYFLAGS) | 408 (to->m_flags & (M_EXT | M_EXTPG)); 409 if ((to->m_flags & M_EXT) == 0) 410 to->m_data = to->m_pktdat; 411 to->m_pkthdr = from->m_pkthdr; /* especially tags */ 412 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */ 413 from->m_flags &= ~M_PKTHDR; 414 if (from->m_pkthdr.csum_flags & CSUM_SND_TAG) { 415 from->m_pkthdr.csum_flags &= ~CSUM_SND_TAG; 416 from->m_pkthdr.snd_tag = NULL; 417 } 418 } 419 420 /* 421 * Duplicate "from"'s mbuf pkthdr in "to". 422 * "from" must have M_PKTHDR set, and "to" must be empty. 423 * In particular, this does a deep copy of the packet tags. 424 */ 425 int 426 m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how) 427 { 428 429 #if 0 430 /* 431 * The mbuf allocator only initializes the pkthdr 432 * when the mbuf is allocated with m_gethdr(). Many users 433 * (e.g. m_copy*, m_prepend) use m_get() and then 434 * smash the pkthdr as needed causing these 435 * assertions to trip. For now just disable them. 436 */ 437 M_ASSERTPKTHDR(to); 438 /* Note: with MAC, this may not be a good assertion. */ 439 KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_dup_pkthdr: to has tags")); 440 #endif 441 MBUF_CHECKSLEEP(how); 442 #ifdef MAC 443 if (to->m_flags & M_PKTHDR) 444 m_tag_delete_chain(to, NULL); 445 #endif 446 to->m_flags = (from->m_flags & M_COPYFLAGS) | 447 (to->m_flags & (M_EXT | M_EXTPG)); 448 if ((to->m_flags & M_EXT) == 0) 449 to->m_data = to->m_pktdat; 450 to->m_pkthdr = from->m_pkthdr; 451 if (from->m_pkthdr.csum_flags & CSUM_SND_TAG) 452 m_snd_tag_ref(from->m_pkthdr.snd_tag); 453 SLIST_INIT(&to->m_pkthdr.tags); 454 return (m_tag_copy_chain(to, from, how)); 455 } 456 457 /* 458 * Lesser-used path for M_PREPEND: 459 * allocate new mbuf to prepend to chain, 460 * copy junk along. 461 */ 462 struct mbuf * 463 m_prepend(struct mbuf *m, int len, int how) 464 { 465 struct mbuf *mn; 466 467 if (m->m_flags & M_PKTHDR) 468 mn = m_gethdr(how, m->m_type); 469 else 470 mn = m_get(how, m->m_type); 471 if (mn == NULL) { 472 m_freem(m); 473 return (NULL); 474 } 475 if (m->m_flags & M_PKTHDR) 476 m_move_pkthdr(mn, m); 477 mn->m_next = m; 478 m = mn; 479 if (len < M_SIZE(m)) 480 M_ALIGN(m, len); 481 m->m_len = len; 482 return (m); 483 } 484 485 /* 486 * Make a copy of an mbuf chain starting "off0" bytes from the beginning, 487 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf. 488 * The wait parameter is a choice of M_WAITOK/M_NOWAIT from caller. 489 * Note that the copy is read-only, because clusters are not copied, 490 * only their reference counts are incremented. 491 */ 492 struct mbuf * 493 m_copym(struct mbuf *m, int off0, int len, int wait) 494 { 495 struct mbuf *n, **np; 496 int off = off0; 497 struct mbuf *top; 498 int copyhdr = 0; 499 500 KASSERT(off >= 0, ("m_copym, negative off %d", off)); 501 KASSERT(len >= 0, ("m_copym, negative len %d", len)); 502 MBUF_CHECKSLEEP(wait); 503 if (off == 0 && m->m_flags & M_PKTHDR) 504 copyhdr = 1; 505 while (off > 0) { 506 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain")); 507 if (off < m->m_len) 508 break; 509 off -= m->m_len; 510 m = m->m_next; 511 } 512 np = ⊤ 513 top = NULL; 514 while (len > 0) { 515 if (m == NULL) { 516 KASSERT(len == M_COPYALL, 517 ("m_copym, length > size of mbuf chain")); 518 break; 519 } 520 if (copyhdr) 521 n = m_gethdr(wait, m->m_type); 522 else 523 n = m_get(wait, m->m_type); 524 *np = n; 525 if (n == NULL) 526 goto nospace; 527 if (copyhdr) { 528 if (!m_dup_pkthdr(n, m, wait)) 529 goto nospace; 530 if (len == M_COPYALL) 531 n->m_pkthdr.len -= off0; 532 else 533 n->m_pkthdr.len = len; 534 copyhdr = 0; 535 } 536 n->m_len = min(len, m->m_len - off); 537 if (m->m_flags & (M_EXT|M_EXTPG)) { 538 n->m_data = m->m_data + off; 539 mb_dupcl(n, m); 540 } else 541 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t), 542 (u_int)n->m_len); 543 if (len != M_COPYALL) 544 len -= n->m_len; 545 off = 0; 546 m = m->m_next; 547 np = &n->m_next; 548 } 549 550 return (top); 551 nospace: 552 m_freem(top); 553 return (NULL); 554 } 555 556 /* 557 * Copy an entire packet, including header (which must be present). 558 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'. 559 * Note that the copy is read-only, because clusters are not copied, 560 * only their reference counts are incremented. 561 * Preserve alignment of the first mbuf so if the creator has left 562 * some room at the beginning (e.g. for inserting protocol headers) 563 * the copies still have the room available. 564 */ 565 struct mbuf * 566 m_copypacket(struct mbuf *m, int how) 567 { 568 struct mbuf *top, *n, *o; 569 570 MBUF_CHECKSLEEP(how); 571 n = m_get(how, m->m_type); 572 top = n; 573 if (n == NULL) 574 goto nospace; 575 576 if (!m_dup_pkthdr(n, m, how)) 577 goto nospace; 578 n->m_len = m->m_len; 579 if (m->m_flags & (M_EXT|M_EXTPG)) { 580 n->m_data = m->m_data; 581 mb_dupcl(n, m); 582 } else { 583 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat ); 584 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 585 } 586 587 m = m->m_next; 588 while (m) { 589 o = m_get(how, m->m_type); 590 if (o == NULL) 591 goto nospace; 592 593 n->m_next = o; 594 n = n->m_next; 595 596 n->m_len = m->m_len; 597 if (m->m_flags & (M_EXT|M_EXTPG)) { 598 n->m_data = m->m_data; 599 mb_dupcl(n, m); 600 } else { 601 bcopy(mtod(m, char *), mtod(n, char *), n->m_len); 602 } 603 604 m = m->m_next; 605 } 606 return top; 607 nospace: 608 m_freem(top); 609 return (NULL); 610 } 611 612 static void 613 m_copyfromunmapped(const struct mbuf *m, int off, int len, caddr_t cp) 614 { 615 struct iovec iov; 616 struct uio uio; 617 int error; 618 619 KASSERT(off >= 0, ("m_copyfromunmapped: negative off %d", off)); 620 KASSERT(len >= 0, ("m_copyfromunmapped: negative len %d", len)); 621 KASSERT(off < m->m_len, 622 ("m_copyfromunmapped: len exceeds mbuf length")); 623 iov.iov_base = cp; 624 iov.iov_len = len; 625 uio.uio_resid = len; 626 uio.uio_iov = &iov; 627 uio.uio_segflg = UIO_SYSSPACE; 628 uio.uio_iovcnt = 1; 629 uio.uio_offset = 0; 630 uio.uio_rw = UIO_READ; 631 error = m_unmappedtouio(m, off, &uio, len); 632 KASSERT(error == 0, ("m_unmappedtouio failed: off %d, len %d", off, 633 len)); 634 } 635 636 /* 637 * Copy data from an mbuf chain starting "off" bytes from the beginning, 638 * continuing for "len" bytes, into the indicated buffer. 639 */ 640 void 641 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp) 642 { 643 u_int count; 644 645 KASSERT(off >= 0, ("m_copydata, negative off %d", off)); 646 KASSERT(len >= 0, ("m_copydata, negative len %d", len)); 647 while (off > 0) { 648 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain")); 649 if (off < m->m_len) 650 break; 651 off -= m->m_len; 652 m = m->m_next; 653 } 654 while (len > 0) { 655 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain")); 656 count = min(m->m_len - off, len); 657 if ((m->m_flags & M_EXTPG) != 0) 658 m_copyfromunmapped(m, off, count, cp); 659 else 660 bcopy(mtod(m, caddr_t) + off, cp, count); 661 len -= count; 662 cp += count; 663 off = 0; 664 m = m->m_next; 665 } 666 } 667 668 /* 669 * Copy a packet header mbuf chain into a completely new chain, including 670 * copying any mbuf clusters. Use this instead of m_copypacket() when 671 * you need a writable copy of an mbuf chain. 672 */ 673 struct mbuf * 674 m_dup(const struct mbuf *m, int how) 675 { 676 struct mbuf **p, *top = NULL; 677 int remain, moff, nsize; 678 679 MBUF_CHECKSLEEP(how); 680 /* Sanity check */ 681 if (m == NULL) 682 return (NULL); 683 M_ASSERTPKTHDR(m); 684 685 /* While there's more data, get a new mbuf, tack it on, and fill it */ 686 remain = m->m_pkthdr.len; 687 moff = 0; 688 p = ⊤ 689 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */ 690 struct mbuf *n; 691 692 /* Get the next new mbuf */ 693 if (remain >= MINCLSIZE) { 694 n = m_getcl(how, m->m_type, 0); 695 nsize = MCLBYTES; 696 } else { 697 n = m_get(how, m->m_type); 698 nsize = MLEN; 699 } 700 if (n == NULL) 701 goto nospace; 702 703 if (top == NULL) { /* First one, must be PKTHDR */ 704 if (!m_dup_pkthdr(n, m, how)) { 705 m_free(n); 706 goto nospace; 707 } 708 if ((n->m_flags & M_EXT) == 0) 709 nsize = MHLEN; 710 n->m_flags &= ~M_RDONLY; 711 } 712 n->m_len = 0; 713 714 /* Link it into the new chain */ 715 *p = n; 716 p = &n->m_next; 717 718 /* Copy data from original mbuf(s) into new mbuf */ 719 while (n->m_len < nsize && m != NULL) { 720 int chunk = min(nsize - n->m_len, m->m_len - moff); 721 722 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk); 723 moff += chunk; 724 n->m_len += chunk; 725 remain -= chunk; 726 if (moff == m->m_len) { 727 m = m->m_next; 728 moff = 0; 729 } 730 } 731 732 /* Check correct total mbuf length */ 733 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL), 734 ("%s: bogus m_pkthdr.len", __func__)); 735 } 736 return (top); 737 738 nospace: 739 m_freem(top); 740 return (NULL); 741 } 742 743 /* 744 * Concatenate mbuf chain n to m. 745 * Both chains must be of the same type (e.g. MT_DATA). 746 * Any m_pkthdr is not updated. 747 */ 748 void 749 m_cat(struct mbuf *m, struct mbuf *n) 750 { 751 while (m->m_next) 752 m = m->m_next; 753 while (n) { 754 if (!M_WRITABLE(m) || 755 (n->m_flags & M_EXTPG) != 0 || 756 M_TRAILINGSPACE(m) < n->m_len) { 757 /* just join the two chains */ 758 m->m_next = n; 759 return; 760 } 761 /* splat the data from one into the other */ 762 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 763 (u_int)n->m_len); 764 m->m_len += n->m_len; 765 n = m_free(n); 766 } 767 } 768 769 /* 770 * Concatenate two pkthdr mbuf chains. 771 */ 772 void 773 m_catpkt(struct mbuf *m, struct mbuf *n) 774 { 775 776 M_ASSERTPKTHDR(m); 777 M_ASSERTPKTHDR(n); 778 779 m->m_pkthdr.len += n->m_pkthdr.len; 780 m_demote(n, 1, 0); 781 782 m_cat(m, n); 783 } 784 785 void 786 m_adj(struct mbuf *mp, int req_len) 787 { 788 int len = req_len; 789 struct mbuf *m; 790 int count; 791 792 if ((m = mp) == NULL) 793 return; 794 if (len >= 0) { 795 /* 796 * Trim from head. 797 */ 798 while (m != NULL && len > 0) { 799 if (m->m_len <= len) { 800 len -= m->m_len; 801 m->m_len = 0; 802 m = m->m_next; 803 } else { 804 m->m_len -= len; 805 m->m_data += len; 806 len = 0; 807 } 808 } 809 if (mp->m_flags & M_PKTHDR) 810 mp->m_pkthdr.len -= (req_len - len); 811 } else { 812 /* 813 * Trim from tail. Scan the mbuf chain, 814 * calculating its length and finding the last mbuf. 815 * If the adjustment only affects this mbuf, then just 816 * adjust and return. Otherwise, rescan and truncate 817 * after the remaining size. 818 */ 819 len = -len; 820 count = 0; 821 for (;;) { 822 count += m->m_len; 823 if (m->m_next == (struct mbuf *)0) 824 break; 825 m = m->m_next; 826 } 827 if (m->m_len >= len) { 828 m->m_len -= len; 829 if (mp->m_flags & M_PKTHDR) 830 mp->m_pkthdr.len -= len; 831 return; 832 } 833 count -= len; 834 if (count < 0) 835 count = 0; 836 /* 837 * Correct length for chain is "count". 838 * Find the mbuf with last data, adjust its length, 839 * and toss data from remaining mbufs on chain. 840 */ 841 m = mp; 842 if (m->m_flags & M_PKTHDR) 843 m->m_pkthdr.len = count; 844 for (; m; m = m->m_next) { 845 if (m->m_len >= count) { 846 m->m_len = count; 847 if (m->m_next != NULL) { 848 m_freem(m->m_next); 849 m->m_next = NULL; 850 } 851 break; 852 } 853 count -= m->m_len; 854 } 855 } 856 } 857 858 /* 859 * Rearange an mbuf chain so that len bytes are contiguous 860 * and in the data area of an mbuf (so that mtod will work 861 * for a structure of size len). Returns the resulting 862 * mbuf chain on success, frees it and returns null on failure. 863 * If there is room, it will add up to max_protohdr-len extra bytes to the 864 * contiguous region in an attempt to avoid being called next time. 865 */ 866 struct mbuf * 867 m_pullup(struct mbuf *n, int len) 868 { 869 struct mbuf *m; 870 int count; 871 int space; 872 873 KASSERT((n->m_flags & M_EXTPG) == 0, 874 ("%s: unmapped mbuf %p", __func__, n)); 875 876 /* 877 * If first mbuf has no cluster, and has room for len bytes 878 * without shifting current data, pullup into it, 879 * otherwise allocate a new mbuf to prepend to the chain. 880 */ 881 if ((n->m_flags & M_EXT) == 0 && 882 n->m_data + len < &n->m_dat[MLEN] && n->m_next) { 883 if (n->m_len >= len) 884 return (n); 885 m = n; 886 n = n->m_next; 887 len -= m->m_len; 888 } else { 889 if (len > MHLEN) 890 goto bad; 891 m = m_get(M_NOWAIT, n->m_type); 892 if (m == NULL) 893 goto bad; 894 if (n->m_flags & M_PKTHDR) 895 m_move_pkthdr(m, n); 896 } 897 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 898 do { 899 count = min(min(max(len, max_protohdr), space), n->m_len); 900 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, 901 (u_int)count); 902 len -= count; 903 m->m_len += count; 904 n->m_len -= count; 905 space -= count; 906 if (n->m_len) 907 n->m_data += count; 908 else 909 n = m_free(n); 910 } while (len > 0 && n); 911 if (len > 0) { 912 (void) m_free(m); 913 goto bad; 914 } 915 m->m_next = n; 916 return (m); 917 bad: 918 m_freem(n); 919 return (NULL); 920 } 921 922 /* 923 * Like m_pullup(), except a new mbuf is always allocated, and we allow 924 * the amount of empty space before the data in the new mbuf to be specified 925 * (in the event that the caller expects to prepend later). 926 */ 927 struct mbuf * 928 m_copyup(struct mbuf *n, int len, int dstoff) 929 { 930 struct mbuf *m; 931 int count, space; 932 933 if (len > (MHLEN - dstoff)) 934 goto bad; 935 m = m_get(M_NOWAIT, n->m_type); 936 if (m == NULL) 937 goto bad; 938 if (n->m_flags & M_PKTHDR) 939 m_move_pkthdr(m, n); 940 m->m_data += dstoff; 941 space = &m->m_dat[MLEN] - (m->m_data + m->m_len); 942 do { 943 count = min(min(max(len, max_protohdr), space), n->m_len); 944 memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t), 945 (unsigned)count); 946 len -= count; 947 m->m_len += count; 948 n->m_len -= count; 949 space -= count; 950 if (n->m_len) 951 n->m_data += count; 952 else 953 n = m_free(n); 954 } while (len > 0 && n); 955 if (len > 0) { 956 (void) m_free(m); 957 goto bad; 958 } 959 m->m_next = n; 960 return (m); 961 bad: 962 m_freem(n); 963 return (NULL); 964 } 965 966 /* 967 * Partition an mbuf chain in two pieces, returning the tail -- 968 * all but the first len0 bytes. In case of failure, it returns NULL and 969 * attempts to restore the chain to its original state. 970 * 971 * Note that the resulting mbufs might be read-only, because the new 972 * mbuf can end up sharing an mbuf cluster with the original mbuf if 973 * the "breaking point" happens to lie within a cluster mbuf. Use the 974 * M_WRITABLE() macro to check for this case. 975 */ 976 struct mbuf * 977 m_split(struct mbuf *m0, int len0, int wait) 978 { 979 struct mbuf *m, *n; 980 u_int len = len0, remain; 981 982 MBUF_CHECKSLEEP(wait); 983 for (m = m0; m && len > m->m_len; m = m->m_next) 984 len -= m->m_len; 985 if (m == NULL) 986 return (NULL); 987 remain = m->m_len - len; 988 if (m0->m_flags & M_PKTHDR && remain == 0) { 989 n = m_gethdr(wait, m0->m_type); 990 if (n == NULL) 991 return (NULL); 992 n->m_next = m->m_next; 993 m->m_next = NULL; 994 if (m0->m_pkthdr.csum_flags & CSUM_SND_TAG) { 995 n->m_pkthdr.snd_tag = 996 m_snd_tag_ref(m0->m_pkthdr.snd_tag); 997 n->m_pkthdr.csum_flags |= CSUM_SND_TAG; 998 } else 999 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; 1000 n->m_pkthdr.len = m0->m_pkthdr.len - len0; 1001 m0->m_pkthdr.len = len0; 1002 return (n); 1003 } else if (m0->m_flags & M_PKTHDR) { 1004 n = m_gethdr(wait, m0->m_type); 1005 if (n == NULL) 1006 return (NULL); 1007 if (m0->m_pkthdr.csum_flags & CSUM_SND_TAG) { 1008 n->m_pkthdr.snd_tag = 1009 m_snd_tag_ref(m0->m_pkthdr.snd_tag); 1010 n->m_pkthdr.csum_flags |= CSUM_SND_TAG; 1011 } else 1012 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; 1013 n->m_pkthdr.len = m0->m_pkthdr.len - len0; 1014 m0->m_pkthdr.len = len0; 1015 if (m->m_flags & (M_EXT|M_EXTPG)) 1016 goto extpacket; 1017 if (remain > MHLEN) { 1018 /* m can't be the lead packet */ 1019 M_ALIGN(n, 0); 1020 n->m_next = m_split(m, len, wait); 1021 if (n->m_next == NULL) { 1022 (void) m_free(n); 1023 return (NULL); 1024 } else { 1025 n->m_len = 0; 1026 return (n); 1027 } 1028 } else 1029 M_ALIGN(n, remain); 1030 } else if (remain == 0) { 1031 n = m->m_next; 1032 m->m_next = NULL; 1033 return (n); 1034 } else { 1035 n = m_get(wait, m->m_type); 1036 if (n == NULL) 1037 return (NULL); 1038 M_ALIGN(n, remain); 1039 } 1040 extpacket: 1041 if (m->m_flags & (M_EXT|M_EXTPG)) { 1042 n->m_data = m->m_data + len; 1043 mb_dupcl(n, m); 1044 } else { 1045 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain); 1046 } 1047 n->m_len = remain; 1048 m->m_len = len; 1049 n->m_next = m->m_next; 1050 m->m_next = NULL; 1051 return (n); 1052 } 1053 /* 1054 * Routine to copy from device local memory into mbufs. 1055 * Note that `off' argument is offset into first mbuf of target chain from 1056 * which to begin copying the data to. 1057 */ 1058 struct mbuf * 1059 m_devget(char *buf, int totlen, int off, struct ifnet *ifp, 1060 void (*copy)(char *from, caddr_t to, u_int len)) 1061 { 1062 struct mbuf *m; 1063 struct mbuf *top = NULL, **mp = ⊤ 1064 int len; 1065 1066 if (off < 0 || off > MHLEN) 1067 return (NULL); 1068 1069 while (totlen > 0) { 1070 if (top == NULL) { /* First one, must be PKTHDR */ 1071 if (totlen + off >= MINCLSIZE) { 1072 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR); 1073 len = MCLBYTES; 1074 } else { 1075 m = m_gethdr(M_NOWAIT, MT_DATA); 1076 len = MHLEN; 1077 1078 /* Place initial small packet/header at end of mbuf */ 1079 if (m && totlen + off + max_linkhdr <= MHLEN) { 1080 m->m_data += max_linkhdr; 1081 len -= max_linkhdr; 1082 } 1083 } 1084 if (m == NULL) 1085 return NULL; 1086 m->m_pkthdr.rcvif = ifp; 1087 m->m_pkthdr.len = totlen; 1088 } else { 1089 if (totlen + off >= MINCLSIZE) { 1090 m = m_getcl(M_NOWAIT, MT_DATA, 0); 1091 len = MCLBYTES; 1092 } else { 1093 m = m_get(M_NOWAIT, MT_DATA); 1094 len = MLEN; 1095 } 1096 if (m == NULL) { 1097 m_freem(top); 1098 return NULL; 1099 } 1100 } 1101 if (off) { 1102 m->m_data += off; 1103 len -= off; 1104 off = 0; 1105 } 1106 m->m_len = len = min(totlen, len); 1107 if (copy) 1108 copy(buf, mtod(m, caddr_t), (u_int)len); 1109 else 1110 bcopy(buf, mtod(m, caddr_t), (u_int)len); 1111 buf += len; 1112 *mp = m; 1113 mp = &m->m_next; 1114 totlen -= len; 1115 } 1116 return (top); 1117 } 1118 1119 /* 1120 * Copy data from a buffer back into the indicated mbuf chain, 1121 * starting "off" bytes from the beginning, extending the mbuf 1122 * chain if necessary. 1123 */ 1124 void 1125 m_copyback(struct mbuf *m0, int off, int len, c_caddr_t cp) 1126 { 1127 int mlen; 1128 struct mbuf *m = m0, *n; 1129 int totlen = 0; 1130 1131 if (m0 == NULL) 1132 return; 1133 while (off > (mlen = m->m_len)) { 1134 off -= mlen; 1135 totlen += mlen; 1136 if (m->m_next == NULL) { 1137 n = m_get(M_NOWAIT, m->m_type); 1138 if (n == NULL) 1139 goto out; 1140 bzero(mtod(n, caddr_t), MLEN); 1141 n->m_len = min(MLEN, len + off); 1142 m->m_next = n; 1143 } 1144 m = m->m_next; 1145 } 1146 while (len > 0) { 1147 if (m->m_next == NULL && (len > m->m_len - off)) { 1148 m->m_len += min(len - (m->m_len - off), 1149 M_TRAILINGSPACE(m)); 1150 } 1151 mlen = min (m->m_len - off, len); 1152 bcopy(cp, off + mtod(m, caddr_t), (u_int)mlen); 1153 cp += mlen; 1154 len -= mlen; 1155 mlen += off; 1156 off = 0; 1157 totlen += mlen; 1158 if (len == 0) 1159 break; 1160 if (m->m_next == NULL) { 1161 n = m_get(M_NOWAIT, m->m_type); 1162 if (n == NULL) 1163 break; 1164 n->m_len = min(MLEN, len); 1165 m->m_next = n; 1166 } 1167 m = m->m_next; 1168 } 1169 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) 1170 m->m_pkthdr.len = totlen; 1171 } 1172 1173 /* 1174 * Append the specified data to the indicated mbuf chain, 1175 * Extend the mbuf chain if the new data does not fit in 1176 * existing space. 1177 * 1178 * Return 1 if able to complete the job; otherwise 0. 1179 */ 1180 int 1181 m_append(struct mbuf *m0, int len, c_caddr_t cp) 1182 { 1183 struct mbuf *m, *n; 1184 int remainder, space; 1185 1186 for (m = m0; m->m_next != NULL; m = m->m_next) 1187 ; 1188 remainder = len; 1189 space = M_TRAILINGSPACE(m); 1190 if (space > 0) { 1191 /* 1192 * Copy into available space. 1193 */ 1194 if (space > remainder) 1195 space = remainder; 1196 bcopy(cp, mtod(m, caddr_t) + m->m_len, space); 1197 m->m_len += space; 1198 cp += space, remainder -= space; 1199 } 1200 while (remainder > 0) { 1201 /* 1202 * Allocate a new mbuf; could check space 1203 * and allocate a cluster instead. 1204 */ 1205 n = m_get(M_NOWAIT, m->m_type); 1206 if (n == NULL) 1207 break; 1208 n->m_len = min(MLEN, remainder); 1209 bcopy(cp, mtod(n, caddr_t), n->m_len); 1210 cp += n->m_len, remainder -= n->m_len; 1211 m->m_next = n; 1212 m = n; 1213 } 1214 if (m0->m_flags & M_PKTHDR) 1215 m0->m_pkthdr.len += len - remainder; 1216 return (remainder == 0); 1217 } 1218 1219 /* 1220 * Apply function f to the data in an mbuf chain starting "off" bytes from 1221 * the beginning, continuing for "len" bytes. 1222 */ 1223 int 1224 m_apply(struct mbuf *m, int off, int len, 1225 int (*f)(void *, void *, u_int), void *arg) 1226 { 1227 u_int count; 1228 int rval; 1229 1230 KASSERT(off >= 0, ("m_apply, negative off %d", off)); 1231 KASSERT(len >= 0, ("m_apply, negative len %d", len)); 1232 while (off > 0) { 1233 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain")); 1234 if (off < m->m_len) 1235 break; 1236 off -= m->m_len; 1237 m = m->m_next; 1238 } 1239 while (len > 0) { 1240 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain")); 1241 count = min(m->m_len - off, len); 1242 rval = (*f)(arg, mtod(m, caddr_t) + off, count); 1243 if (rval) 1244 return (rval); 1245 len -= count; 1246 off = 0; 1247 m = m->m_next; 1248 } 1249 return (0); 1250 } 1251 1252 /* 1253 * Return a pointer to mbuf/offset of location in mbuf chain. 1254 */ 1255 struct mbuf * 1256 m_getptr(struct mbuf *m, int loc, int *off) 1257 { 1258 1259 while (loc >= 0) { 1260 /* Normal end of search. */ 1261 if (m->m_len > loc) { 1262 *off = loc; 1263 return (m); 1264 } else { 1265 loc -= m->m_len; 1266 if (m->m_next == NULL) { 1267 if (loc == 0) { 1268 /* Point at the end of valid data. */ 1269 *off = m->m_len; 1270 return (m); 1271 } 1272 return (NULL); 1273 } 1274 m = m->m_next; 1275 } 1276 } 1277 return (NULL); 1278 } 1279 1280 void 1281 m_print(const struct mbuf *m, int maxlen) 1282 { 1283 int len; 1284 int pdata; 1285 const struct mbuf *m2; 1286 1287 if (m == NULL) { 1288 printf("mbuf: %p\n", m); 1289 return; 1290 } 1291 1292 if (m->m_flags & M_PKTHDR) 1293 len = m->m_pkthdr.len; 1294 else 1295 len = -1; 1296 m2 = m; 1297 while (m2 != NULL && (len == -1 || len)) { 1298 pdata = m2->m_len; 1299 if (maxlen != -1 && pdata > maxlen) 1300 pdata = maxlen; 1301 printf("mbuf: %p len: %d, next: %p, %b%s", m2, m2->m_len, 1302 m2->m_next, m2->m_flags, "\2\20freelist\17skipfw" 1303 "\11proto5\10proto4\7proto3\6proto2\5proto1\4rdonly" 1304 "\3eor\2pkthdr\1ext", pdata ? "" : "\n"); 1305 if (pdata) 1306 printf(", %*D\n", pdata, (u_char *)m2->m_data, "-"); 1307 if (len != -1) 1308 len -= m2->m_len; 1309 m2 = m2->m_next; 1310 } 1311 if (len > 0) 1312 printf("%d bytes unaccounted for.\n", len); 1313 return; 1314 } 1315 1316 u_int 1317 m_fixhdr(struct mbuf *m0) 1318 { 1319 u_int len; 1320 1321 len = m_length(m0, NULL); 1322 m0->m_pkthdr.len = len; 1323 return (len); 1324 } 1325 1326 u_int 1327 m_length(struct mbuf *m0, struct mbuf **last) 1328 { 1329 struct mbuf *m; 1330 u_int len; 1331 1332 len = 0; 1333 for (m = m0; m != NULL; m = m->m_next) { 1334 len += m->m_len; 1335 if (m->m_next == NULL) 1336 break; 1337 } 1338 if (last != NULL) 1339 *last = m; 1340 return (len); 1341 } 1342 1343 /* 1344 * Defragment a mbuf chain, returning the shortest possible 1345 * chain of mbufs and clusters. If allocation fails and 1346 * this cannot be completed, NULL will be returned, but 1347 * the passed in chain will be unchanged. Upon success, 1348 * the original chain will be freed, and the new chain 1349 * will be returned. 1350 * 1351 * If a non-packet header is passed in, the original 1352 * mbuf (chain?) will be returned unharmed. 1353 */ 1354 struct mbuf * 1355 m_defrag(struct mbuf *m0, int how) 1356 { 1357 struct mbuf *m_new = NULL, *m_final = NULL; 1358 int progress = 0, length; 1359 1360 MBUF_CHECKSLEEP(how); 1361 if (!(m0->m_flags & M_PKTHDR)) 1362 return (m0); 1363 1364 m_fixhdr(m0); /* Needed sanity check */ 1365 1366 #ifdef MBUF_STRESS_TEST 1367 if (m_defragrandomfailures) { 1368 int temp = arc4random() & 0xff; 1369 if (temp == 0xba) 1370 goto nospace; 1371 } 1372 #endif 1373 1374 if (m0->m_pkthdr.len > MHLEN) 1375 m_final = m_getcl(how, MT_DATA, M_PKTHDR); 1376 else 1377 m_final = m_gethdr(how, MT_DATA); 1378 1379 if (m_final == NULL) 1380 goto nospace; 1381 1382 if (m_dup_pkthdr(m_final, m0, how) == 0) 1383 goto nospace; 1384 1385 m_new = m_final; 1386 1387 while (progress < m0->m_pkthdr.len) { 1388 length = m0->m_pkthdr.len - progress; 1389 if (length > MCLBYTES) 1390 length = MCLBYTES; 1391 1392 if (m_new == NULL) { 1393 if (length > MLEN) 1394 m_new = m_getcl(how, MT_DATA, 0); 1395 else 1396 m_new = m_get(how, MT_DATA); 1397 if (m_new == NULL) 1398 goto nospace; 1399 } 1400 1401 m_copydata(m0, progress, length, mtod(m_new, caddr_t)); 1402 progress += length; 1403 m_new->m_len = length; 1404 if (m_new != m_final) 1405 m_cat(m_final, m_new); 1406 m_new = NULL; 1407 } 1408 #ifdef MBUF_STRESS_TEST 1409 if (m0->m_next == NULL) 1410 m_defraguseless++; 1411 #endif 1412 m_freem(m0); 1413 m0 = m_final; 1414 #ifdef MBUF_STRESS_TEST 1415 m_defragpackets++; 1416 m_defragbytes += m0->m_pkthdr.len; 1417 #endif 1418 return (m0); 1419 nospace: 1420 #ifdef MBUF_STRESS_TEST 1421 m_defragfailure++; 1422 #endif 1423 if (m_final) 1424 m_freem(m_final); 1425 return (NULL); 1426 } 1427 1428 /* 1429 * Return the number of fragments an mbuf will use. This is usually 1430 * used as a proxy for the number of scatter/gather elements needed by 1431 * a DMA engine to access an mbuf. In general mapped mbufs are 1432 * assumed to be backed by physically contiguous buffers that only 1433 * need a single fragment. Unmapped mbufs, on the other hand, can 1434 * span disjoint physical pages. 1435 */ 1436 static int 1437 frags_per_mbuf(struct mbuf *m) 1438 { 1439 int frags; 1440 1441 if ((m->m_flags & M_EXTPG) == 0) 1442 return (1); 1443 1444 /* 1445 * The header and trailer are counted as a single fragment 1446 * each when present. 1447 * 1448 * XXX: This overestimates the number of fragments by assuming 1449 * all the backing physical pages are disjoint. 1450 */ 1451 frags = 0; 1452 if (m->m_epg_hdrlen != 0) 1453 frags++; 1454 frags += m->m_epg_npgs; 1455 if (m->m_epg_trllen != 0) 1456 frags++; 1457 1458 return (frags); 1459 } 1460 1461 /* 1462 * Defragment an mbuf chain, returning at most maxfrags separate 1463 * mbufs+clusters. If this is not possible NULL is returned and 1464 * the original mbuf chain is left in its present (potentially 1465 * modified) state. We use two techniques: collapsing consecutive 1466 * mbufs and replacing consecutive mbufs by a cluster. 1467 * 1468 * NB: this should really be named m_defrag but that name is taken 1469 */ 1470 struct mbuf * 1471 m_collapse(struct mbuf *m0, int how, int maxfrags) 1472 { 1473 struct mbuf *m, *n, *n2, **prev; 1474 u_int curfrags; 1475 1476 /* 1477 * Calculate the current number of frags. 1478 */ 1479 curfrags = 0; 1480 for (m = m0; m != NULL; m = m->m_next) 1481 curfrags += frags_per_mbuf(m); 1482 /* 1483 * First, try to collapse mbufs. Note that we always collapse 1484 * towards the front so we don't need to deal with moving the 1485 * pkthdr. This may be suboptimal if the first mbuf has much 1486 * less data than the following. 1487 */ 1488 m = m0; 1489 again: 1490 for (;;) { 1491 n = m->m_next; 1492 if (n == NULL) 1493 break; 1494 if (M_WRITABLE(m) && 1495 n->m_len < M_TRAILINGSPACE(m)) { 1496 m_copydata(n, 0, n->m_len, 1497 mtod(m, char *) + m->m_len); 1498 m->m_len += n->m_len; 1499 m->m_next = n->m_next; 1500 curfrags -= frags_per_mbuf(n); 1501 m_free(n); 1502 if (curfrags <= maxfrags) 1503 return m0; 1504 } else 1505 m = n; 1506 } 1507 KASSERT(maxfrags > 1, 1508 ("maxfrags %u, but normal collapse failed", maxfrags)); 1509 /* 1510 * Collapse consecutive mbufs to a cluster. 1511 */ 1512 prev = &m0->m_next; /* NB: not the first mbuf */ 1513 while ((n = *prev) != NULL) { 1514 if ((n2 = n->m_next) != NULL && 1515 n->m_len + n2->m_len < MCLBYTES) { 1516 m = m_getcl(how, MT_DATA, 0); 1517 if (m == NULL) 1518 goto bad; 1519 m_copydata(n, 0, n->m_len, mtod(m, char *)); 1520 m_copydata(n2, 0, n2->m_len, 1521 mtod(m, char *) + n->m_len); 1522 m->m_len = n->m_len + n2->m_len; 1523 m->m_next = n2->m_next; 1524 *prev = m; 1525 curfrags += 1; /* For the new cluster */ 1526 curfrags -= frags_per_mbuf(n); 1527 curfrags -= frags_per_mbuf(n2); 1528 m_free(n); 1529 m_free(n2); 1530 if (curfrags <= maxfrags) 1531 return m0; 1532 /* 1533 * Still not there, try the normal collapse 1534 * again before we allocate another cluster. 1535 */ 1536 goto again; 1537 } 1538 prev = &n->m_next; 1539 } 1540 /* 1541 * No place where we can collapse to a cluster; punt. 1542 * This can occur if, for example, you request 2 frags 1543 * but the packet requires that both be clusters (we 1544 * never reallocate the first mbuf to avoid moving the 1545 * packet header). 1546 */ 1547 bad: 1548 return NULL; 1549 } 1550 1551 #ifdef MBUF_STRESS_TEST 1552 1553 /* 1554 * Fragment an mbuf chain. There's no reason you'd ever want to do 1555 * this in normal usage, but it's great for stress testing various 1556 * mbuf consumers. 1557 * 1558 * If fragmentation is not possible, the original chain will be 1559 * returned. 1560 * 1561 * Possible length values: 1562 * 0 no fragmentation will occur 1563 * > 0 each fragment will be of the specified length 1564 * -1 each fragment will be the same random value in length 1565 * -2 each fragment's length will be entirely random 1566 * (Random values range from 1 to 256) 1567 */ 1568 struct mbuf * 1569 m_fragment(struct mbuf *m0, int how, int length) 1570 { 1571 struct mbuf *m_first, *m_last; 1572 int divisor = 255, progress = 0, fraglen; 1573 1574 if (!(m0->m_flags & M_PKTHDR)) 1575 return (m0); 1576 1577 if (length == 0 || length < -2) 1578 return (m0); 1579 if (length > MCLBYTES) 1580 length = MCLBYTES; 1581 if (length < 0 && divisor > MCLBYTES) 1582 divisor = MCLBYTES; 1583 if (length == -1) 1584 length = 1 + (arc4random() % divisor); 1585 if (length > 0) 1586 fraglen = length; 1587 1588 m_fixhdr(m0); /* Needed sanity check */ 1589 1590 m_first = m_getcl(how, MT_DATA, M_PKTHDR); 1591 if (m_first == NULL) 1592 goto nospace; 1593 1594 if (m_dup_pkthdr(m_first, m0, how) == 0) 1595 goto nospace; 1596 1597 m_last = m_first; 1598 1599 while (progress < m0->m_pkthdr.len) { 1600 if (length == -2) 1601 fraglen = 1 + (arc4random() % divisor); 1602 if (fraglen > m0->m_pkthdr.len - progress) 1603 fraglen = m0->m_pkthdr.len - progress; 1604 1605 if (progress != 0) { 1606 struct mbuf *m_new = m_getcl(how, MT_DATA, 0); 1607 if (m_new == NULL) 1608 goto nospace; 1609 1610 m_last->m_next = m_new; 1611 m_last = m_new; 1612 } 1613 1614 m_copydata(m0, progress, fraglen, mtod(m_last, caddr_t)); 1615 progress += fraglen; 1616 m_last->m_len = fraglen; 1617 } 1618 m_freem(m0); 1619 m0 = m_first; 1620 return (m0); 1621 nospace: 1622 if (m_first) 1623 m_freem(m_first); 1624 /* Return the original chain on failure */ 1625 return (m0); 1626 } 1627 1628 #endif 1629 1630 /* 1631 * Free pages from mbuf_ext_pgs, assuming they were allocated via 1632 * vm_page_alloc() and aren't associated with any object. Complement 1633 * to allocator from m_uiotombuf_nomap(). 1634 */ 1635 void 1636 mb_free_mext_pgs(struct mbuf *m) 1637 { 1638 vm_page_t pg; 1639 1640 M_ASSERTEXTPG(m); 1641 for (int i = 0; i < m->m_epg_npgs; i++) { 1642 pg = PHYS_TO_VM_PAGE(m->m_epg_pa[i]); 1643 vm_page_unwire_noq(pg); 1644 vm_page_free(pg); 1645 } 1646 } 1647 1648 static struct mbuf * 1649 m_uiotombuf_nomap(struct uio *uio, int how, int len, int maxseg, int flags) 1650 { 1651 struct mbuf *m, *mb, *prev; 1652 vm_page_t pg_array[MBUF_PEXT_MAX_PGS]; 1653 int error, length, i, needed; 1654 ssize_t total; 1655 int pflags = malloc2vm_flags(how) | VM_ALLOC_NOOBJ | VM_ALLOC_NODUMP | 1656 VM_ALLOC_WIRED; 1657 1658 MPASS((flags & M_PKTHDR) == 0); 1659 1660 /* 1661 * len can be zero or an arbitrary large value bound by 1662 * the total data supplied by the uio. 1663 */ 1664 if (len > 0) 1665 total = MIN(uio->uio_resid, len); 1666 else 1667 total = uio->uio_resid; 1668 1669 if (maxseg == 0) 1670 maxseg = MBUF_PEXT_MAX_PGS * PAGE_SIZE; 1671 1672 /* 1673 * If total is zero, return an empty mbuf. This can occur 1674 * for TLS 1.0 connections which send empty fragments as 1675 * a countermeasure against the known-IV weakness in CBC 1676 * ciphersuites. 1677 */ 1678 if (__predict_false(total == 0)) { 1679 mb = mb_alloc_ext_pgs(how, mb_free_mext_pgs); 1680 if (mb == NULL) 1681 return (NULL); 1682 mb->m_epg_flags = EPG_FLAG_ANON; 1683 return (mb); 1684 } 1685 1686 /* 1687 * Allocate the pages 1688 */ 1689 m = NULL; 1690 while (total > 0) { 1691 mb = mb_alloc_ext_pgs(how, mb_free_mext_pgs); 1692 if (mb == NULL) 1693 goto failed; 1694 if (m == NULL) 1695 m = mb; 1696 else 1697 prev->m_next = mb; 1698 prev = mb; 1699 mb->m_epg_flags = EPG_FLAG_ANON; 1700 needed = length = MIN(maxseg, total); 1701 for (i = 0; needed > 0; i++, needed -= PAGE_SIZE) { 1702 retry_page: 1703 pg_array[i] = vm_page_alloc(NULL, 0, pflags); 1704 if (pg_array[i] == NULL) { 1705 if (how & M_NOWAIT) { 1706 goto failed; 1707 } else { 1708 vm_wait(NULL); 1709 goto retry_page; 1710 } 1711 } 1712 pg_array[i]->flags &= ~PG_ZERO; 1713 mb->m_epg_pa[i] = VM_PAGE_TO_PHYS(pg_array[i]); 1714 mb->m_epg_npgs++; 1715 } 1716 mb->m_epg_last_len = length - PAGE_SIZE * (mb->m_epg_npgs - 1); 1717 MBUF_EXT_PGS_ASSERT_SANITY(mb); 1718 total -= length; 1719 error = uiomove_fromphys(pg_array, 0, length, uio); 1720 if (error != 0) 1721 goto failed; 1722 mb->m_len = length; 1723 mb->m_ext.ext_size += PAGE_SIZE * mb->m_epg_npgs; 1724 if (flags & M_PKTHDR) 1725 m->m_pkthdr.len += length; 1726 } 1727 return (m); 1728 1729 failed: 1730 m_freem(m); 1731 return (NULL); 1732 } 1733 1734 /* 1735 * Copy the contents of uio into a properly sized mbuf chain. 1736 */ 1737 struct mbuf * 1738 m_uiotombuf(struct uio *uio, int how, int len, int align, int flags) 1739 { 1740 struct mbuf *m, *mb; 1741 int error, length; 1742 ssize_t total; 1743 int progress = 0; 1744 1745 if (flags & M_EXTPG) 1746 return (m_uiotombuf_nomap(uio, how, len, align, flags)); 1747 1748 /* 1749 * len can be zero or an arbitrary large value bound by 1750 * the total data supplied by the uio. 1751 */ 1752 if (len > 0) 1753 total = (uio->uio_resid < len) ? uio->uio_resid : len; 1754 else 1755 total = uio->uio_resid; 1756 1757 /* 1758 * The smallest unit returned by m_getm2() is a single mbuf 1759 * with pkthdr. We can't align past it. 1760 */ 1761 if (align >= MHLEN) 1762 return (NULL); 1763 1764 /* 1765 * Give us the full allocation or nothing. 1766 * If len is zero return the smallest empty mbuf. 1767 */ 1768 m = m_getm2(NULL, max(total + align, 1), how, MT_DATA, flags); 1769 if (m == NULL) 1770 return (NULL); 1771 m->m_data += align; 1772 1773 /* Fill all mbufs with uio data and update header information. */ 1774 for (mb = m; mb != NULL; mb = mb->m_next) { 1775 length = min(M_TRAILINGSPACE(mb), total - progress); 1776 1777 error = uiomove(mtod(mb, void *), length, uio); 1778 if (error) { 1779 m_freem(m); 1780 return (NULL); 1781 } 1782 1783 mb->m_len = length; 1784 progress += length; 1785 if (flags & M_PKTHDR) 1786 m->m_pkthdr.len += length; 1787 } 1788 KASSERT(progress == total, ("%s: progress != total", __func__)); 1789 1790 return (m); 1791 } 1792 1793 /* 1794 * Copy data from an unmapped mbuf into a uio limited by len if set. 1795 */ 1796 int 1797 m_unmappedtouio(const struct mbuf *m, int m_off, struct uio *uio, int len) 1798 { 1799 vm_page_t pg; 1800 int error, i, off, pglen, pgoff, seglen, segoff; 1801 1802 M_ASSERTEXTPG(m); 1803 error = 0; 1804 1805 /* Skip over any data removed from the front. */ 1806 off = mtod(m, vm_offset_t); 1807 1808 off += m_off; 1809 if (m->m_epg_hdrlen != 0) { 1810 if (off >= m->m_epg_hdrlen) { 1811 off -= m->m_epg_hdrlen; 1812 } else { 1813 seglen = m->m_epg_hdrlen - off; 1814 segoff = off; 1815 seglen = min(seglen, len); 1816 off = 0; 1817 len -= seglen; 1818 error = uiomove(__DECONST(void *, 1819 &m->m_epg_hdr[segoff]), seglen, uio); 1820 } 1821 } 1822 pgoff = m->m_epg_1st_off; 1823 for (i = 0; i < m->m_epg_npgs && error == 0 && len > 0; i++) { 1824 pglen = m_epg_pagelen(m, i, pgoff); 1825 if (off >= pglen) { 1826 off -= pglen; 1827 pgoff = 0; 1828 continue; 1829 } 1830 seglen = pglen - off; 1831 segoff = pgoff + off; 1832 off = 0; 1833 seglen = min(seglen, len); 1834 len -= seglen; 1835 pg = PHYS_TO_VM_PAGE(m->m_epg_pa[i]); 1836 error = uiomove_fromphys(&pg, segoff, seglen, uio); 1837 pgoff = 0; 1838 }; 1839 if (len != 0 && error == 0) { 1840 KASSERT((off + len) <= m->m_epg_trllen, 1841 ("off + len > trail (%d + %d > %d, m_off = %d)", off, len, 1842 m->m_epg_trllen, m_off)); 1843 error = uiomove(__DECONST(void *, &m->m_epg_trail[off]), 1844 len, uio); 1845 } 1846 return (error); 1847 } 1848 1849 /* 1850 * Copy an mbuf chain into a uio limited by len if set. 1851 */ 1852 int 1853 m_mbuftouio(struct uio *uio, const struct mbuf *m, int len) 1854 { 1855 int error, length, total; 1856 int progress = 0; 1857 1858 if (len > 0) 1859 total = min(uio->uio_resid, len); 1860 else 1861 total = uio->uio_resid; 1862 1863 /* Fill the uio with data from the mbufs. */ 1864 for (; m != NULL; m = m->m_next) { 1865 length = min(m->m_len, total - progress); 1866 1867 if ((m->m_flags & M_EXTPG) != 0) 1868 error = m_unmappedtouio(m, 0, uio, length); 1869 else 1870 error = uiomove(mtod(m, void *), length, uio); 1871 if (error) 1872 return (error); 1873 1874 progress += length; 1875 } 1876 1877 return (0); 1878 } 1879 1880 /* 1881 * Create a writable copy of the mbuf chain. While doing this 1882 * we compact the chain with a goal of producing a chain with 1883 * at most two mbufs. The second mbuf in this chain is likely 1884 * to be a cluster. The primary purpose of this work is to create 1885 * a writable packet for encryption, compression, etc. The 1886 * secondary goal is to linearize the data so the data can be 1887 * passed to crypto hardware in the most efficient manner possible. 1888 */ 1889 struct mbuf * 1890 m_unshare(struct mbuf *m0, int how) 1891 { 1892 struct mbuf *m, *mprev; 1893 struct mbuf *n, *mfirst, *mlast; 1894 int len, off; 1895 1896 mprev = NULL; 1897 for (m = m0; m != NULL; m = mprev->m_next) { 1898 /* 1899 * Regular mbufs are ignored unless there's a cluster 1900 * in front of it that we can use to coalesce. We do 1901 * the latter mainly so later clusters can be coalesced 1902 * also w/o having to handle them specially (i.e. convert 1903 * mbuf+cluster -> cluster). This optimization is heavily 1904 * influenced by the assumption that we're running over 1905 * Ethernet where MCLBYTES is large enough that the max 1906 * packet size will permit lots of coalescing into a 1907 * single cluster. This in turn permits efficient 1908 * crypto operations, especially when using hardware. 1909 */ 1910 if ((m->m_flags & M_EXT) == 0) { 1911 if (mprev && (mprev->m_flags & M_EXT) && 1912 m->m_len <= M_TRAILINGSPACE(mprev)) { 1913 /* XXX: this ignores mbuf types */ 1914 memcpy(mtod(mprev, caddr_t) + mprev->m_len, 1915 mtod(m, caddr_t), m->m_len); 1916 mprev->m_len += m->m_len; 1917 mprev->m_next = m->m_next; /* unlink from chain */ 1918 m_free(m); /* reclaim mbuf */ 1919 } else { 1920 mprev = m; 1921 } 1922 continue; 1923 } 1924 /* 1925 * Writable mbufs are left alone (for now). 1926 */ 1927 if (M_WRITABLE(m)) { 1928 mprev = m; 1929 continue; 1930 } 1931 1932 /* 1933 * Not writable, replace with a copy or coalesce with 1934 * the previous mbuf if possible (since we have to copy 1935 * it anyway, we try to reduce the number of mbufs and 1936 * clusters so that future work is easier). 1937 */ 1938 KASSERT(m->m_flags & M_EXT, ("m_flags 0x%x", m->m_flags)); 1939 /* NB: we only coalesce into a cluster or larger */ 1940 if (mprev != NULL && (mprev->m_flags & M_EXT) && 1941 m->m_len <= M_TRAILINGSPACE(mprev)) { 1942 /* XXX: this ignores mbuf types */ 1943 memcpy(mtod(mprev, caddr_t) + mprev->m_len, 1944 mtod(m, caddr_t), m->m_len); 1945 mprev->m_len += m->m_len; 1946 mprev->m_next = m->m_next; /* unlink from chain */ 1947 m_free(m); /* reclaim mbuf */ 1948 continue; 1949 } 1950 1951 /* 1952 * Allocate new space to hold the copy and copy the data. 1953 * We deal with jumbo mbufs (i.e. m_len > MCLBYTES) by 1954 * splitting them into clusters. We could just malloc a 1955 * buffer and make it external but too many device drivers 1956 * don't know how to break up the non-contiguous memory when 1957 * doing DMA. 1958 */ 1959 n = m_getcl(how, m->m_type, m->m_flags & M_COPYFLAGS); 1960 if (n == NULL) { 1961 m_freem(m0); 1962 return (NULL); 1963 } 1964 if (m->m_flags & M_PKTHDR) { 1965 KASSERT(mprev == NULL, ("%s: m0 %p, m %p has M_PKTHDR", 1966 __func__, m0, m)); 1967 m_move_pkthdr(n, m); 1968 } 1969 len = m->m_len; 1970 off = 0; 1971 mfirst = n; 1972 mlast = NULL; 1973 for (;;) { 1974 int cc = min(len, MCLBYTES); 1975 memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, cc); 1976 n->m_len = cc; 1977 if (mlast != NULL) 1978 mlast->m_next = n; 1979 mlast = n; 1980 #if 0 1981 newipsecstat.ips_clcopied++; 1982 #endif 1983 1984 len -= cc; 1985 if (len <= 0) 1986 break; 1987 off += cc; 1988 1989 n = m_getcl(how, m->m_type, m->m_flags & M_COPYFLAGS); 1990 if (n == NULL) { 1991 m_freem(mfirst); 1992 m_freem(m0); 1993 return (NULL); 1994 } 1995 } 1996 n->m_next = m->m_next; 1997 if (mprev == NULL) 1998 m0 = mfirst; /* new head of chain */ 1999 else 2000 mprev->m_next = mfirst; /* replace old mbuf */ 2001 m_free(m); /* release old mbuf */ 2002 mprev = mfirst; 2003 } 2004 return (m0); 2005 } 2006 2007 #ifdef MBUF_PROFILING 2008 2009 #define MP_BUCKETS 32 /* don't just change this as things may overflow.*/ 2010 struct mbufprofile { 2011 uintmax_t wasted[MP_BUCKETS]; 2012 uintmax_t used[MP_BUCKETS]; 2013 uintmax_t segments[MP_BUCKETS]; 2014 } mbprof; 2015 2016 #define MP_MAXDIGITS 21 /* strlen("16,000,000,000,000,000,000") == 21 */ 2017 #define MP_NUMLINES 6 2018 #define MP_NUMSPERLINE 16 2019 #define MP_EXTRABYTES 64 /* > strlen("used:\nwasted:\nsegments:\n") */ 2020 /* work out max space needed and add a bit of spare space too */ 2021 #define MP_MAXLINE ((MP_MAXDIGITS+1) * MP_NUMSPERLINE) 2022 #define MP_BUFSIZE ((MP_MAXLINE * MP_NUMLINES) + 1 + MP_EXTRABYTES) 2023 2024 char mbprofbuf[MP_BUFSIZE]; 2025 2026 void 2027 m_profile(struct mbuf *m) 2028 { 2029 int segments = 0; 2030 int used = 0; 2031 int wasted = 0; 2032 2033 while (m) { 2034 segments++; 2035 used += m->m_len; 2036 if (m->m_flags & M_EXT) { 2037 wasted += MHLEN - sizeof(m->m_ext) + 2038 m->m_ext.ext_size - m->m_len; 2039 } else { 2040 if (m->m_flags & M_PKTHDR) 2041 wasted += MHLEN - m->m_len; 2042 else 2043 wasted += MLEN - m->m_len; 2044 } 2045 m = m->m_next; 2046 } 2047 /* be paranoid.. it helps */ 2048 if (segments > MP_BUCKETS - 1) 2049 segments = MP_BUCKETS - 1; 2050 if (used > 100000) 2051 used = 100000; 2052 if (wasted > 100000) 2053 wasted = 100000; 2054 /* store in the appropriate bucket */ 2055 /* don't bother locking. if it's slightly off, so what? */ 2056 mbprof.segments[segments]++; 2057 mbprof.used[fls(used)]++; 2058 mbprof.wasted[fls(wasted)]++; 2059 } 2060 2061 static void 2062 mbprof_textify(void) 2063 { 2064 int offset; 2065 char *c; 2066 uint64_t *p; 2067 2068 p = &mbprof.wasted[0]; 2069 c = mbprofbuf; 2070 offset = snprintf(c, MP_MAXLINE + 10, 2071 "wasted:\n" 2072 "%ju %ju %ju %ju %ju %ju %ju %ju " 2073 "%ju %ju %ju %ju %ju %ju %ju %ju\n", 2074 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], 2075 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); 2076 #ifdef BIG_ARRAY 2077 p = &mbprof.wasted[16]; 2078 c += offset; 2079 offset = snprintf(c, MP_MAXLINE, 2080 "%ju %ju %ju %ju %ju %ju %ju %ju " 2081 "%ju %ju %ju %ju %ju %ju %ju %ju\n", 2082 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], 2083 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); 2084 #endif 2085 p = &mbprof.used[0]; 2086 c += offset; 2087 offset = snprintf(c, MP_MAXLINE + 10, 2088 "used:\n" 2089 "%ju %ju %ju %ju %ju %ju %ju %ju " 2090 "%ju %ju %ju %ju %ju %ju %ju %ju\n", 2091 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], 2092 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); 2093 #ifdef BIG_ARRAY 2094 p = &mbprof.used[16]; 2095 c += offset; 2096 offset = snprintf(c, MP_MAXLINE, 2097 "%ju %ju %ju %ju %ju %ju %ju %ju " 2098 "%ju %ju %ju %ju %ju %ju %ju %ju\n", 2099 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], 2100 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); 2101 #endif 2102 p = &mbprof.segments[0]; 2103 c += offset; 2104 offset = snprintf(c, MP_MAXLINE + 10, 2105 "segments:\n" 2106 "%ju %ju %ju %ju %ju %ju %ju %ju " 2107 "%ju %ju %ju %ju %ju %ju %ju %ju\n", 2108 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], 2109 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); 2110 #ifdef BIG_ARRAY 2111 p = &mbprof.segments[16]; 2112 c += offset; 2113 offset = snprintf(c, MP_MAXLINE, 2114 "%ju %ju %ju %ju %ju %ju %ju %ju " 2115 "%ju %ju %ju %ju %ju %ju %ju %jju", 2116 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], 2117 p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); 2118 #endif 2119 } 2120 2121 static int 2122 mbprof_handler(SYSCTL_HANDLER_ARGS) 2123 { 2124 int error; 2125 2126 mbprof_textify(); 2127 error = SYSCTL_OUT(req, mbprofbuf, strlen(mbprofbuf) + 1); 2128 return (error); 2129 } 2130 2131 static int 2132 mbprof_clr_handler(SYSCTL_HANDLER_ARGS) 2133 { 2134 int clear, error; 2135 2136 clear = 0; 2137 error = sysctl_handle_int(oidp, &clear, 0, req); 2138 if (error || !req->newptr) 2139 return (error); 2140 2141 if (clear) { 2142 bzero(&mbprof, sizeof(mbprof)); 2143 } 2144 2145 return (error); 2146 } 2147 2148 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofile, 2149 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT, NULL, 0, 2150 mbprof_handler, "A", 2151 "mbuf profiling statistics"); 2152 2153 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofileclr, 2154 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0, 2155 mbprof_clr_handler, "I", 2156 "clear mbuf profiling statistics"); 2157 #endif
Cache object: c9c9d880f9dc4e27dcf987e4e86250eb
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