/*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1982, 1986, 1988, 1991, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94 */ #include __FBSDID("$FreeBSD$"); #include "opt_param.h" #include "opt_mbuf_stress_test.h" #include "opt_mbuf_profiling.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include SDT_PROBE_DEFINE5_XLATE(sdt, , , m__init, "struct mbuf *", "mbufinfo_t *", "uint32_t", "uint32_t", "uint16_t", "uint16_t", "uint32_t", "uint32_t", "uint32_t", "uint32_t"); SDT_PROBE_DEFINE3_XLATE(sdt, , , m__gethdr, "uint32_t", "uint32_t", "uint16_t", "uint16_t", "struct mbuf *", "mbufinfo_t *"); SDT_PROBE_DEFINE3_XLATE(sdt, , , m__get, "uint32_t", "uint32_t", "uint16_t", "uint16_t", "struct mbuf *", "mbufinfo_t *"); SDT_PROBE_DEFINE4_XLATE(sdt, , , m__getcl, "uint32_t", "uint32_t", "uint16_t", "uint16_t", "uint32_t", "uint32_t", "struct mbuf *", "mbufinfo_t *"); SDT_PROBE_DEFINE5_XLATE(sdt, , , m__getjcl, "uint32_t", "uint32_t", "uint16_t", "uint16_t", "uint32_t", "uint32_t", "uint32_t", "uint32_t", "struct mbuf *", "mbufinfo_t *"); SDT_PROBE_DEFINE3_XLATE(sdt, , , m__clget, "struct mbuf *", "mbufinfo_t *", "uint32_t", "uint32_t", "uint32_t", "uint32_t"); SDT_PROBE_DEFINE4_XLATE(sdt, , , m__cljget, "struct mbuf *", "mbufinfo_t *", "uint32_t", "uint32_t", "uint32_t", "uint32_t", "void*", "void*"); SDT_PROBE_DEFINE(sdt, , , m__cljset); SDT_PROBE_DEFINE1_XLATE(sdt, , , m__free, "struct mbuf *", "mbufinfo_t *"); SDT_PROBE_DEFINE1_XLATE(sdt, , , m__freem, "struct mbuf *", "mbufinfo_t *"); #include int max_linkhdr; int max_protohdr; int max_hdr; int max_datalen; #ifdef MBUF_STRESS_TEST int m_defragpackets; int m_defragbytes; int m_defraguseless; int m_defragfailure; int m_defragrandomfailures; #endif /* * sysctl(8) exported objects */ SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RD, &max_linkhdr, 0, "Size of largest link layer header"); SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RD, &max_protohdr, 0, "Size of largest protocol layer header"); SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RD, &max_hdr, 0, "Size of largest link plus protocol header"); SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RD, &max_datalen, 0, "Minimum space left in mbuf after max_hdr"); #ifdef MBUF_STRESS_TEST SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD, &m_defragpackets, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD, &m_defragbytes, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD, &m_defraguseless, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD, &m_defragfailure, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW, &m_defragrandomfailures, 0, ""); #endif /* * Ensure the correct size of various mbuf parameters. It could be off due * to compiler-induced padding and alignment artifacts. */ CTASSERT(MSIZE - offsetof(struct mbuf, m_dat) == MLEN); CTASSERT(MSIZE - offsetof(struct mbuf, m_pktdat) == MHLEN); /* * mbuf data storage should be 64-bit aligned regardless of architectural * pointer size; check this is the case with and without a packet header. */ CTASSERT(offsetof(struct mbuf, m_dat) % 8 == 0); CTASSERT(offsetof(struct mbuf, m_pktdat) % 8 == 0); /* * While the specific values here don't matter too much (i.e., +/- a few * words), we do want to ensure that changes to these values are carefully * reasoned about and properly documented. This is especially the case as * network-protocol and device-driver modules encode these layouts, and must * be recompiled if the structures change. Check these values at compile time * against the ones documented in comments in mbuf.h. * * NB: Possibly they should be documented there via #define's and not just * comments. */ #if defined(__LP64__) CTASSERT(offsetof(struct mbuf, m_dat) == 32); CTASSERT(sizeof(struct pkthdr) == 56); CTASSERT(sizeof(struct m_ext) == 160); #else CTASSERT(offsetof(struct mbuf, m_dat) == 24); CTASSERT(sizeof(struct pkthdr) == 48); #if defined(__powerpc__) && defined(BOOKE) /* PowerPC booke has 64-bit physical pointers. */ CTASSERT(sizeof(struct m_ext) == 184); #else CTASSERT(sizeof(struct m_ext) == 180); #endif #endif /* * Assert that the queue(3) macros produce code of the same size as an old * plain pointer does. */ #ifdef INVARIANTS static struct mbuf __used m_assertbuf; CTASSERT(sizeof(m_assertbuf.m_slist) == sizeof(m_assertbuf.m_next)); CTASSERT(sizeof(m_assertbuf.m_stailq) == sizeof(m_assertbuf.m_next)); CTASSERT(sizeof(m_assertbuf.m_slistpkt) == sizeof(m_assertbuf.m_nextpkt)); CTASSERT(sizeof(m_assertbuf.m_stailqpkt) == sizeof(m_assertbuf.m_nextpkt)); #endif /* * Attach the cluster from *m to *n, set up m_ext in *n * and bump the refcount of the cluster. */ void mb_dupcl(struct mbuf *n, struct mbuf *m) { volatile u_int *refcnt; KASSERT(m->m_flags & (M_EXT|M_EXTPG), ("%s: M_EXT|M_EXTPG not set on %p", __func__, m)); KASSERT(!(n->m_flags & (M_EXT|M_EXTPG)), ("%s: M_EXT|M_EXTPG set on %p", __func__, n)); /* * Cache access optimization. * * o Regular M_EXT storage doesn't need full copy of m_ext, since * the holder of the 'ext_count' is responsible to carry the free * routine and its arguments. * o M_EXTPG data is split between main part of mbuf and m_ext, the * main part is copied in full, the m_ext part is similar to M_EXT. * o EXT_EXTREF, where 'ext_cnt' doesn't point into mbuf at all, is * special - it needs full copy of m_ext into each mbuf, since any * copy could end up as the last to free. */ if (m->m_flags & M_EXTPG) { bcopy(&m->m_epg_startcopy, &n->m_epg_startcopy, __rangeof(struct mbuf, m_epg_startcopy, m_epg_endcopy)); bcopy(&m->m_ext, &n->m_ext, m_epg_ext_copylen); } else if (m->m_ext.ext_type == EXT_EXTREF) bcopy(&m->m_ext, &n->m_ext, sizeof(struct m_ext)); else bcopy(&m->m_ext, &n->m_ext, m_ext_copylen); n->m_flags |= m->m_flags & (M_RDONLY | M_EXT | M_EXTPG); /* See if this is the mbuf that holds the embedded refcount. */ if (m->m_ext.ext_flags & EXT_FLAG_EMBREF) { refcnt = n->m_ext.ext_cnt = &m->m_ext.ext_count; n->m_ext.ext_flags &= ~EXT_FLAG_EMBREF; } else { KASSERT(m->m_ext.ext_cnt != NULL, ("%s: no refcounting pointer on %p", __func__, m)); refcnt = m->m_ext.ext_cnt; } if (*refcnt == 1) *refcnt += 1; else atomic_add_int(refcnt, 1); } void m_demote_pkthdr(struct mbuf *m) { M_ASSERTPKTHDR(m); m_tag_delete_chain(m, NULL); m->m_flags &= ~M_PKTHDR; bzero(&m->m_pkthdr, sizeof(struct pkthdr)); } /* * Clean up mbuf (chain) from any tags and packet headers. * If "all" is set then the first mbuf in the chain will be * cleaned too. */ void m_demote(struct mbuf *m0, int all, int flags) { struct mbuf *m; for (m = all ? m0 : m0->m_next; m != NULL; m = m->m_next) { KASSERT(m->m_nextpkt == NULL, ("%s: m_nextpkt in m %p, m0 %p", __func__, m, m0)); if (m->m_flags & M_PKTHDR) m_demote_pkthdr(m); m->m_flags = m->m_flags & (M_EXT | M_RDONLY | M_NOFREE | M_EXTPG | flags); } } /* * Sanity checks on mbuf (chain) for use in KASSERT() and general * debugging. * Returns 0 or panics when bad and 1 on all tests passed. * Sanitize, 0 to run M_SANITY_ACTION, 1 to garble things so they * blow up later. */ int m_sanity(struct mbuf *m0, int sanitize) { struct mbuf *m; caddr_t a, b; int pktlen = 0; #ifdef INVARIANTS #define M_SANITY_ACTION(s) panic("mbuf %p: " s, m) #else #define M_SANITY_ACTION(s) printf("mbuf %p: " s, m) #endif for (m = m0; m != NULL; m = m->m_next) { /* * Basic pointer checks. If any of these fails then some * unrelated kernel memory before or after us is trashed. * No way to recover from that. */ a = M_START(m); b = a + M_SIZE(m); if ((caddr_t)m->m_data < a) M_SANITY_ACTION("m_data outside mbuf data range left"); if ((caddr_t)m->m_data > b) M_SANITY_ACTION("m_data outside mbuf data range right"); if ((caddr_t)m->m_data + m->m_len > b) M_SANITY_ACTION("m_data + m_len exeeds mbuf space"); /* m->m_nextpkt may only be set on first mbuf in chain. */ if (m != m0 && m->m_nextpkt != NULL) { if (sanitize) { m_freem(m->m_nextpkt); m->m_nextpkt = (struct mbuf *)0xDEADC0DE; } else M_SANITY_ACTION("m->m_nextpkt on in-chain mbuf"); } /* packet length (not mbuf length!) calculation */ if (m0->m_flags & M_PKTHDR) pktlen += m->m_len; /* m_tags may only be attached to first mbuf in chain. */ if (m != m0 && m->m_flags & M_PKTHDR && !SLIST_EMPTY(&m->m_pkthdr.tags)) { if (sanitize) { m_tag_delete_chain(m, NULL); /* put in 0xDEADC0DE perhaps? */ } else M_SANITY_ACTION("m_tags on in-chain mbuf"); } /* M_PKTHDR may only be set on first mbuf in chain */ if (m != m0 && m->m_flags & M_PKTHDR) { if (sanitize) { bzero(&m->m_pkthdr, sizeof(m->m_pkthdr)); m->m_flags &= ~M_PKTHDR; /* put in 0xDEADCODE and leave hdr flag in */ } else M_SANITY_ACTION("M_PKTHDR on in-chain mbuf"); } } m = m0; if (pktlen && pktlen != m->m_pkthdr.len) { if (sanitize) m->m_pkthdr.len = 0; else M_SANITY_ACTION("m_pkthdr.len != mbuf chain length"); } return 1; #undef M_SANITY_ACTION } /* * Non-inlined part of m_init(). */ int m_pkthdr_init(struct mbuf *m, int how) { #ifdef MAC int error; #endif m->m_data = m->m_pktdat; bzero(&m->m_pkthdr, sizeof(m->m_pkthdr)); #ifdef NUMA m->m_pkthdr.numa_domain = M_NODOM; #endif #ifdef MAC /* If the label init fails, fail the alloc */ error = mac_mbuf_init(m, how); if (error) return (error); #endif return (0); } /* * "Move" mbuf pkthdr from "from" to "to". * "from" must have M_PKTHDR set, and "to" must be empty. */ void m_move_pkthdr(struct mbuf *to, struct mbuf *from) { #if 0 /* see below for why these are not enabled */ M_ASSERTPKTHDR(to); /* Note: with MAC, this may not be a good assertion. */ KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_move_pkthdr: to has tags")); #endif #ifdef MAC /* * XXXMAC: It could be this should also occur for non-MAC? */ if (to->m_flags & M_PKTHDR) m_tag_delete_chain(to, NULL); #endif to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & (M_EXT | M_EXTPG)); if ((to->m_flags & M_EXT) == 0) to->m_data = to->m_pktdat; to->m_pkthdr = from->m_pkthdr; /* especially tags */ SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */ from->m_flags &= ~M_PKTHDR; if (from->m_pkthdr.csum_flags & CSUM_SND_TAG) { from->m_pkthdr.csum_flags &= ~CSUM_SND_TAG; from->m_pkthdr.snd_tag = NULL; } } /* * Duplicate "from"'s mbuf pkthdr in "to". * "from" must have M_PKTHDR set, and "to" must be empty. * In particular, this does a deep copy of the packet tags. */ int m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how) { #if 0 /* * The mbuf allocator only initializes the pkthdr * when the mbuf is allocated with m_gethdr(). Many users * (e.g. m_copy*, m_prepend) use m_get() and then * smash the pkthdr as needed causing these * assertions to trip. For now just disable them. */ M_ASSERTPKTHDR(to); /* Note: with MAC, this may not be a good assertion. */ KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_dup_pkthdr: to has tags")); #endif MBUF_CHECKSLEEP(how); #ifdef MAC if (to->m_flags & M_PKTHDR) m_tag_delete_chain(to, NULL); #endif to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & (M_EXT | M_EXTPG)); if ((to->m_flags & M_EXT) == 0) to->m_data = to->m_pktdat; to->m_pkthdr = from->m_pkthdr; if (from->m_pkthdr.csum_flags & CSUM_SND_TAG) m_snd_tag_ref(from->m_pkthdr.snd_tag); SLIST_INIT(&to->m_pkthdr.tags); return (m_tag_copy_chain(to, from, how)); } /* * Lesser-used path for M_PREPEND: * allocate new mbuf to prepend to chain, * copy junk along. */ struct mbuf * m_prepend(struct mbuf *m, int len, int how) { struct mbuf *mn; if (m->m_flags & M_PKTHDR) mn = m_gethdr(how, m->m_type); else mn = m_get(how, m->m_type); if (mn == NULL) { m_freem(m); return (NULL); } if (m->m_flags & M_PKTHDR) m_move_pkthdr(mn, m); mn->m_next = m; m = mn; if (len < M_SIZE(m)) M_ALIGN(m, len); m->m_len = len; return (m); } /* * Make a copy of an mbuf chain starting "off0" bytes from the beginning, * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf. * The wait parameter is a choice of M_WAITOK/M_NOWAIT from caller. * Note that the copy is read-only, because clusters are not copied, * only their reference counts are incremented. */ struct mbuf * m_copym(struct mbuf *m, int off0, int len, int wait) { struct mbuf *n, **np; int off = off0; struct mbuf *top; int copyhdr = 0; KASSERT(off >= 0, ("m_copym, negative off %d", off)); KASSERT(len >= 0, ("m_copym, negative len %d", len)); MBUF_CHECKSLEEP(wait); if (off == 0 && m->m_flags & M_PKTHDR) copyhdr = 1; while (off > 0) { KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain")); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } np = ⊤ top = NULL; while (len > 0) { if (m == NULL) { KASSERT(len == M_COPYALL, ("m_copym, length > size of mbuf chain")); break; } if (copyhdr) n = m_gethdr(wait, m->m_type); else n = m_get(wait, m->m_type); *np = n; if (n == NULL) goto nospace; if (copyhdr) { if (!m_dup_pkthdr(n, m, wait)) goto nospace; if (len == M_COPYALL) n->m_pkthdr.len -= off0; else n->m_pkthdr.len = len; copyhdr = 0; } n->m_len = min(len, m->m_len - off); if (m->m_flags & (M_EXT|M_EXTPG)) { n->m_data = m->m_data + off; mb_dupcl(n, m); } else bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t), (u_int)n->m_len); if (len != M_COPYALL) len -= n->m_len; off = 0; m = m->m_next; np = &n->m_next; } return (top); nospace: m_freem(top); return (NULL); } /* * Copy an entire packet, including header (which must be present). * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'. * Note that the copy is read-only, because clusters are not copied, * only their reference counts are incremented. * Preserve alignment of the first mbuf so if the creator has left * some room at the beginning (e.g. for inserting protocol headers) * the copies still have the room available. */ struct mbuf * m_copypacket(struct mbuf *m, int how) { struct mbuf *top, *n, *o; MBUF_CHECKSLEEP(how); n = m_get(how, m->m_type); top = n; if (n == NULL) goto nospace; if (!m_dup_pkthdr(n, m, how)) goto nospace; n->m_len = m->m_len; if (m->m_flags & (M_EXT|M_EXTPG)) { n->m_data = m->m_data; mb_dupcl(n, m); } else { n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat ); bcopy(mtod(m, char *), mtod(n, char *), n->m_len); } m = m->m_next; while (m) { o = m_get(how, m->m_type); if (o == NULL) goto nospace; n->m_next = o; n = n->m_next; n->m_len = m->m_len; if (m->m_flags & (M_EXT|M_EXTPG)) { n->m_data = m->m_data; mb_dupcl(n, m); } else { bcopy(mtod(m, char *), mtod(n, char *), n->m_len); } m = m->m_next; } return top; nospace: m_freem(top); return (NULL); } static void m_copyfromunmapped(const struct mbuf *m, int off, int len, caddr_t cp) { struct iovec iov; struct uio uio; int error; KASSERT(off >= 0, ("m_copyfromunmapped: negative off %d", off)); KASSERT(len >= 0, ("m_copyfromunmapped: negative len %d", len)); KASSERT(off < m->m_len, ("m_copyfromunmapped: len exceeds mbuf length")); iov.iov_base = cp; iov.iov_len = len; uio.uio_resid = len; uio.uio_iov = &iov; uio.uio_segflg = UIO_SYSSPACE; uio.uio_iovcnt = 1; uio.uio_offset = 0; uio.uio_rw = UIO_READ; error = m_unmappedtouio(m, off, &uio, len); KASSERT(error == 0, ("m_unmappedtouio failed: off %d, len %d", off, len)); } /* * Copy data from an mbuf chain starting "off" bytes from the beginning, * continuing for "len" bytes, into the indicated buffer. */ void m_copydata(const struct mbuf *m, int off, int len, caddr_t cp) { u_int count; KASSERT(off >= 0, ("m_copydata, negative off %d", off)); KASSERT(len >= 0, ("m_copydata, negative len %d", len)); while (off > 0) { KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain")); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } while (len > 0) { KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain")); count = min(m->m_len - off, len); if ((m->m_flags & M_EXTPG) != 0) m_copyfromunmapped(m, off, count, cp); else bcopy(mtod(m, caddr_t) + off, cp, count); len -= count; cp += count; off = 0; m = m->m_next; } } /* * Copy a packet header mbuf chain into a completely new chain, including * copying any mbuf clusters. Use this instead of m_copypacket() when * you need a writable copy of an mbuf chain. */ struct mbuf * m_dup(const struct mbuf *m, int how) { struct mbuf **p, *top = NULL; int remain, moff, nsize; MBUF_CHECKSLEEP(how); /* Sanity check */ if (m == NULL) return (NULL); M_ASSERTPKTHDR(m); /* While there's more data, get a new mbuf, tack it on, and fill it */ remain = m->m_pkthdr.len; moff = 0; p = ⊤ while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */ struct mbuf *n; /* Get the next new mbuf */ if (remain >= MINCLSIZE) { n = m_getcl(how, m->m_type, 0); nsize = MCLBYTES; } else { n = m_get(how, m->m_type); nsize = MLEN; } if (n == NULL) goto nospace; if (top == NULL) { /* First one, must be PKTHDR */ if (!m_dup_pkthdr(n, m, how)) { m_free(n); goto nospace; } if ((n->m_flags & M_EXT) == 0) nsize = MHLEN; n->m_flags &= ~M_RDONLY; } n->m_len = 0; /* Link it into the new chain */ *p = n; p = &n->m_next; /* Copy data from original mbuf(s) into new mbuf */ while (n->m_len < nsize && m != NULL) { int chunk = min(nsize - n->m_len, m->m_len - moff); bcopy(m->m_data + moff, n->m_data + n->m_len, chunk); moff += chunk; n->m_len += chunk; remain -= chunk; if (moff == m->m_len) { m = m->m_next; moff = 0; } } /* Check correct total mbuf length */ KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL), ("%s: bogus m_pkthdr.len", __func__)); } return (top); nospace: m_freem(top); return (NULL); } /* * Concatenate mbuf chain n to m. * Both chains must be of the same type (e.g. MT_DATA). * Any m_pkthdr is not updated. */ void m_cat(struct mbuf *m, struct mbuf *n) { while (m->m_next) m = m->m_next; while (n) { if (!M_WRITABLE(m) || (n->m_flags & M_EXTPG) != 0 || M_TRAILINGSPACE(m) < n->m_len) { /* just join the two chains */ m->m_next = n; return; } /* splat the data from one into the other */ bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, (u_int)n->m_len); m->m_len += n->m_len; n = m_free(n); } } /* * Concatenate two pkthdr mbuf chains. */ void m_catpkt(struct mbuf *m, struct mbuf *n) { M_ASSERTPKTHDR(m); M_ASSERTPKTHDR(n); m->m_pkthdr.len += n->m_pkthdr.len; m_demote(n, 1, 0); m_cat(m, n); } void m_adj(struct mbuf *mp, int req_len) { int len = req_len; struct mbuf *m; int count; if ((m = mp) == NULL) return; if (len >= 0) { /* * Trim from head. */ while (m != NULL && len > 0) { if (m->m_len <= len) { len -= m->m_len; m->m_len = 0; m = m->m_next; } else { m->m_len -= len; m->m_data += len; len = 0; } } if (mp->m_flags & M_PKTHDR) mp->m_pkthdr.len -= (req_len - len); } else { /* * Trim from tail. Scan the mbuf chain, * calculating its length and finding the last mbuf. * If the adjustment only affects this mbuf, then just * adjust and return. Otherwise, rescan and truncate * after the remaining size. */ len = -len; count = 0; for (;;) { count += m->m_len; if (m->m_next == (struct mbuf *)0) break; m = m->m_next; } if (m->m_len >= len) { m->m_len -= len; if (mp->m_flags & M_PKTHDR) mp->m_pkthdr.len -= len; return; } count -= len; if (count < 0) count = 0; /* * Correct length for chain is "count". * Find the mbuf with last data, adjust its length, * and toss data from remaining mbufs on chain. */ m = mp; if (m->m_flags & M_PKTHDR) m->m_pkthdr.len = count; for (; m; m = m->m_next) { if (m->m_len >= count) { m->m_len = count; if (m->m_next != NULL) { m_freem(m->m_next); m->m_next = NULL; } break; } count -= m->m_len; } } } /* * Rearange an mbuf chain so that len bytes are contiguous * and in the data area of an mbuf (so that mtod will work * for a structure of size len). Returns the resulting * mbuf chain on success, frees it and returns null on failure. * If there is room, it will add up to max_protohdr-len extra bytes to the * contiguous region in an attempt to avoid being called next time. */ struct mbuf * m_pullup(struct mbuf *n, int len) { struct mbuf *m; int count; int space; KASSERT((n->m_flags & M_EXTPG) == 0, ("%s: unmapped mbuf %p", __func__, n)); /* * If first mbuf has no cluster, and has room for len bytes * without shifting current data, pullup into it, * otherwise allocate a new mbuf to prepend to the chain. */ if ((n->m_flags & M_EXT) == 0 && n->m_data + len < &n->m_dat[MLEN] && n->m_next) { if (n->m_len >= len) return (n); m = n; n = n->m_next; len -= m->m_len; } else { if (len > MHLEN) goto bad; m = m_get(M_NOWAIT, n->m_type); if (m == NULL) goto bad; if (n->m_flags & M_PKTHDR) m_move_pkthdr(m, n); } space = &m->m_dat[MLEN] - (m->m_data + m->m_len); do { count = min(min(max(len, max_protohdr), space), n->m_len); bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, (u_int)count); len -= count; m->m_len += count; n->m_len -= count; space -= count; if (n->m_len) n->m_data += count; else n = m_free(n); } while (len > 0 && n); if (len > 0) { (void) m_free(m); goto bad; } m->m_next = n; return (m); bad: m_freem(n); return (NULL); } /* * Like m_pullup(), except a new mbuf is always allocated, and we allow * the amount of empty space before the data in the new mbuf to be specified * (in the event that the caller expects to prepend later). */ struct mbuf * m_copyup(struct mbuf *n, int len, int dstoff) { struct mbuf *m; int count, space; if (len > (MHLEN - dstoff)) goto bad; m = m_get(M_NOWAIT, n->m_type); if (m == NULL) goto bad; if (n->m_flags & M_PKTHDR) m_move_pkthdr(m, n); m->m_data += dstoff; space = &m->m_dat[MLEN] - (m->m_data + m->m_len); do { count = min(min(max(len, max_protohdr), space), n->m_len); memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t), (unsigned)count); len -= count; m->m_len += count; n->m_len -= count; space -= count; if (n->m_len) n->m_data += count; else n = m_free(n); } while (len > 0 && n); if (len > 0) { (void) m_free(m); goto bad; } m->m_next = n; return (m); bad: m_freem(n); return (NULL); } /* * Partition an mbuf chain in two pieces, returning the tail -- * all but the first len0 bytes. In case of failure, it returns NULL and * attempts to restore the chain to its original state. * * Note that the resulting mbufs might be read-only, because the new * mbuf can end up sharing an mbuf cluster with the original mbuf if * the "breaking point" happens to lie within a cluster mbuf. Use the * M_WRITABLE() macro to check for this case. */ struct mbuf * m_split(struct mbuf *m0, int len0, int wait) { struct mbuf *m, *n; u_int len = len0, remain; MBUF_CHECKSLEEP(wait); for (m = m0; m && len > m->m_len; m = m->m_next) len -= m->m_len; if (m == NULL) return (NULL); remain = m->m_len - len; if (m0->m_flags & M_PKTHDR && remain == 0) { n = m_gethdr(wait, m0->m_type); if (n == NULL) return (NULL); n->m_next = m->m_next; m->m_next = NULL; if (m0->m_pkthdr.csum_flags & CSUM_SND_TAG) { n->m_pkthdr.snd_tag = m_snd_tag_ref(m0->m_pkthdr.snd_tag); n->m_pkthdr.csum_flags |= CSUM_SND_TAG; } else n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; n->m_pkthdr.len = m0->m_pkthdr.len - len0; m0->m_pkthdr.len = len0; return (n); } else if (m0->m_flags & M_PKTHDR) { n = m_gethdr(wait, m0->m_type); if (n == NULL) return (NULL); if (m0->m_pkthdr.csum_flags & CSUM_SND_TAG) { n->m_pkthdr.snd_tag = m_snd_tag_ref(m0->m_pkthdr.snd_tag); n->m_pkthdr.csum_flags |= CSUM_SND_TAG; } else n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; n->m_pkthdr.len = m0->m_pkthdr.len - len0; m0->m_pkthdr.len = len0; if (m->m_flags & (M_EXT|M_EXTPG)) goto extpacket; if (remain > MHLEN) { /* m can't be the lead packet */ M_ALIGN(n, 0); n->m_next = m_split(m, len, wait); if (n->m_next == NULL) { (void) m_free(n); return (NULL); } else { n->m_len = 0; return (n); } } else M_ALIGN(n, remain); } else if (remain == 0) { n = m->m_next; m->m_next = NULL; return (n); } else { n = m_get(wait, m->m_type); if (n == NULL) return (NULL); M_ALIGN(n, remain); } extpacket: if (m->m_flags & (M_EXT|M_EXTPG)) { n->m_data = m->m_data + len; mb_dupcl(n, m); } else { bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain); } n->m_len = remain; m->m_len = len; n->m_next = m->m_next; m->m_next = NULL; return (n); } /* * Routine to copy from device local memory into mbufs. * Note that `off' argument is offset into first mbuf of target chain from * which to begin copying the data to. */ struct mbuf * m_devget(char *buf, int totlen, int off, struct ifnet *ifp, void (*copy)(char *from, caddr_t to, u_int len)) { struct mbuf *m; struct mbuf *top = NULL, **mp = ⊤ int len; if (off < 0 || off > MHLEN) return (NULL); while (totlen > 0) { if (top == NULL) { /* First one, must be PKTHDR */ if (totlen + off >= MINCLSIZE) { m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR); len = MCLBYTES; } else { m = m_gethdr(M_NOWAIT, MT_DATA); len = MHLEN; /* Place initial small packet/header at end of mbuf */ if (m && totlen + off + max_linkhdr <= MHLEN) { m->m_data += max_linkhdr; len -= max_linkhdr; } } if (m == NULL) return NULL; m->m_pkthdr.rcvif = ifp; m->m_pkthdr.len = totlen; } else { if (totlen + off >= MINCLSIZE) { m = m_getcl(M_NOWAIT, MT_DATA, 0); len = MCLBYTES; } else { m = m_get(M_NOWAIT, MT_DATA); len = MLEN; } if (m == NULL) { m_freem(top); return NULL; } } if (off) { m->m_data += off; len -= off; off = 0; } m->m_len = len = min(totlen, len); if (copy) copy(buf, mtod(m, caddr_t), (u_int)len); else bcopy(buf, mtod(m, caddr_t), (u_int)len); buf += len; *mp = m; mp = &m->m_next; totlen -= len; } return (top); } /* * Copy data from a buffer back into the indicated mbuf chain, * starting "off" bytes from the beginning, extending the mbuf * chain if necessary. */ void m_copyback(struct mbuf *m0, int off, int len, c_caddr_t cp) { int mlen; struct mbuf *m = m0, *n; int totlen = 0; if (m0 == NULL) return; while (off > (mlen = m->m_len)) { off -= mlen; totlen += mlen; if (m->m_next == NULL) { n = m_get(M_NOWAIT, m->m_type); if (n == NULL) goto out; bzero(mtod(n, caddr_t), MLEN); n->m_len = min(MLEN, len + off); m->m_next = n; } m = m->m_next; } while (len > 0) { if (m->m_next == NULL && (len > m->m_len - off)) { m->m_len += min(len - (m->m_len - off), M_TRAILINGSPACE(m)); } mlen = min (m->m_len - off, len); bcopy(cp, off + mtod(m, caddr_t), (u_int)mlen); cp += mlen; len -= mlen; mlen += off; off = 0; totlen += mlen; if (len == 0) break; if (m->m_next == NULL) { n = m_get(M_NOWAIT, m->m_type); if (n == NULL) break; n->m_len = min(MLEN, len); m->m_next = n; } m = m->m_next; } out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) m->m_pkthdr.len = totlen; } /* * Append the specified data to the indicated mbuf chain, * Extend the mbuf chain if the new data does not fit in * existing space. * * Return 1 if able to complete the job; otherwise 0. */ int m_append(struct mbuf *m0, int len, c_caddr_t cp) { struct mbuf *m, *n; int remainder, space; for (m = m0; m->m_next != NULL; m = m->m_next) ; remainder = len; space = M_TRAILINGSPACE(m); if (space > 0) { /* * Copy into available space. */ if (space > remainder) space = remainder; bcopy(cp, mtod(m, caddr_t) + m->m_len, space); m->m_len += space; cp += space, remainder -= space; } while (remainder > 0) { /* * Allocate a new mbuf; could check space * and allocate a cluster instead. */ n = m_get(M_NOWAIT, m->m_type); if (n == NULL) break; n->m_len = min(MLEN, remainder); bcopy(cp, mtod(n, caddr_t), n->m_len); cp += n->m_len, remainder -= n->m_len; m->m_next = n; m = n; } if (m0->m_flags & M_PKTHDR) m0->m_pkthdr.len += len - remainder; return (remainder == 0); } /* * Apply function f to the data in an mbuf chain starting "off" bytes from * the beginning, continuing for "len" bytes. */ int m_apply(struct mbuf *m, int off, int len, int (*f)(void *, void *, u_int), void *arg) { u_int count; int rval; KASSERT(off >= 0, ("m_apply, negative off %d", off)); KASSERT(len >= 0, ("m_apply, negative len %d", len)); while (off > 0) { KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain")); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } while (len > 0) { KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain")); count = min(m->m_len - off, len); rval = (*f)(arg, mtod(m, caddr_t) + off, count); if (rval) return (rval); len -= count; off = 0; m = m->m_next; } return (0); } /* * Return a pointer to mbuf/offset of location in mbuf chain. */ struct mbuf * m_getptr(struct mbuf *m, int loc, int *off) { while (loc >= 0) { /* Normal end of search. */ if (m->m_len > loc) { *off = loc; return (m); } else { loc -= m->m_len; if (m->m_next == NULL) { if (loc == 0) { /* Point at the end of valid data. */ *off = m->m_len; return (m); } return (NULL); } m = m->m_next; } } return (NULL); } void m_print(const struct mbuf *m, int maxlen) { int len; int pdata; const struct mbuf *m2; if (m == NULL) { printf("mbuf: %p\n", m); return; } if (m->m_flags & M_PKTHDR) len = m->m_pkthdr.len; else len = -1; m2 = m; while (m2 != NULL && (len == -1 || len)) { pdata = m2->m_len; if (maxlen != -1 && pdata > maxlen) pdata = maxlen; printf("mbuf: %p len: %d, next: %p, %b%s", m2, m2->m_len, m2->m_next, m2->m_flags, "\20\20freelist\17skipfw" "\11proto5\10proto4\7proto3\6proto2\5proto1\4rdonly" "\3eor\2pkthdr\1ext", pdata ? "" : "\n"); if (pdata) printf(", %*D\n", pdata, (u_char *)m2->m_data, "-"); if (len != -1) len -= m2->m_len; m2 = m2->m_next; } if (len > 0) printf("%d bytes unaccounted for.\n", len); return; } u_int m_fixhdr(struct mbuf *m0) { u_int len; len = m_length(m0, NULL); m0->m_pkthdr.len = len; return (len); } u_int m_length(struct mbuf *m0, struct mbuf **last) { struct mbuf *m; u_int len; len = 0; for (m = m0; m != NULL; m = m->m_next) { len += m->m_len; if (m->m_next == NULL) break; } if (last != NULL) *last = m; return (len); } /* * Defragment a mbuf chain, returning the shortest possible * chain of mbufs and clusters. If allocation fails and * this cannot be completed, NULL will be returned, but * the passed in chain will be unchanged. Upon success, * the original chain will be freed, and the new chain * will be returned. * * If a non-packet header is passed in, the original * mbuf (chain?) will be returned unharmed. */ struct mbuf * m_defrag(struct mbuf *m0, int how) { struct mbuf *m_new = NULL, *m_final = NULL; int progress = 0, length; MBUF_CHECKSLEEP(how); if (!(m0->m_flags & M_PKTHDR)) return (m0); m_fixhdr(m0); /* Needed sanity check */ #ifdef MBUF_STRESS_TEST if (m_defragrandomfailures) { int temp = arc4random() & 0xff; if (temp == 0xba) goto nospace; } #endif if (m0->m_pkthdr.len > MHLEN) m_final = m_getcl(how, MT_DATA, M_PKTHDR); else m_final = m_gethdr(how, MT_DATA); if (m_final == NULL) goto nospace; if (m_dup_pkthdr(m_final, m0, how) == 0) goto nospace; m_new = m_final; while (progress < m0->m_pkthdr.len) { length = m0->m_pkthdr.len - progress; if (length > MCLBYTES) length = MCLBYTES; if (m_new == NULL) { if (length > MLEN) m_new = m_getcl(how, MT_DATA, 0); else m_new = m_get(how, MT_DATA); if (m_new == NULL) goto nospace; } m_copydata(m0, progress, length, mtod(m_new, caddr_t)); progress += length; m_new->m_len = length; if (m_new != m_final) m_cat(m_final, m_new); m_new = NULL; } #ifdef MBUF_STRESS_TEST if (m0->m_next == NULL) m_defraguseless++; #endif m_freem(m0); m0 = m_final; #ifdef MBUF_STRESS_TEST m_defragpackets++; m_defragbytes += m0->m_pkthdr.len; #endif return (m0); nospace: #ifdef MBUF_STRESS_TEST m_defragfailure++; #endif if (m_final) m_freem(m_final); return (NULL); } /* * Return the number of fragments an mbuf will use. This is usually * used as a proxy for the number of scatter/gather elements needed by * a DMA engine to access an mbuf. In general mapped mbufs are * assumed to be backed by physically contiguous buffers that only * need a single fragment. Unmapped mbufs, on the other hand, can * span disjoint physical pages. */ static int frags_per_mbuf(struct mbuf *m) { int frags; if ((m->m_flags & M_EXTPG) == 0) return (1); /* * The header and trailer are counted as a single fragment * each when present. * * XXX: This overestimates the number of fragments by assuming * all the backing physical pages are disjoint. */ frags = 0; if (m->m_epg_hdrlen != 0) frags++; frags += m->m_epg_npgs; if (m->m_epg_trllen != 0) frags++; return (frags); } /* * Defragment an mbuf chain, returning at most maxfrags separate * mbufs+clusters. If this is not possible NULL is returned and * the original mbuf chain is left in its present (potentially * modified) state. We use two techniques: collapsing consecutive * mbufs and replacing consecutive mbufs by a cluster. * * NB: this should really be named m_defrag but that name is taken */ struct mbuf * m_collapse(struct mbuf *m0, int how, int maxfrags) { struct mbuf *m, *n, *n2, **prev; u_int curfrags; /* * Calculate the current number of frags. */ curfrags = 0; for (m = m0; m != NULL; m = m->m_next) curfrags += frags_per_mbuf(m); /* * First, try to collapse mbufs. Note that we always collapse * towards the front so we don't need to deal with moving the * pkthdr. This may be suboptimal if the first mbuf has much * less data than the following. */ m = m0; again: for (;;) { n = m->m_next; if (n == NULL) break; if (M_WRITABLE(m) && n->m_len < M_TRAILINGSPACE(m)) { m_copydata(n, 0, n->m_len, mtod(m, char *) + m->m_len); m->m_len += n->m_len; m->m_next = n->m_next; curfrags -= frags_per_mbuf(n); m_free(n); if (curfrags <= maxfrags) return m0; } else m = n; } KASSERT(maxfrags > 1, ("maxfrags %u, but normal collapse failed", maxfrags)); /* * Collapse consecutive mbufs to a cluster. */ prev = &m0->m_next; /* NB: not the first mbuf */ while ((n = *prev) != NULL) { if ((n2 = n->m_next) != NULL && n->m_len + n2->m_len < MCLBYTES) { m = m_getcl(how, MT_DATA, 0); if (m == NULL) goto bad; m_copydata(n, 0, n->m_len, mtod(m, char *)); m_copydata(n2, 0, n2->m_len, mtod(m, char *) + n->m_len); m->m_len = n->m_len + n2->m_len; m->m_next = n2->m_next; *prev = m; curfrags += 1; /* For the new cluster */ curfrags -= frags_per_mbuf(n); curfrags -= frags_per_mbuf(n2); m_free(n); m_free(n2); if (curfrags <= maxfrags) return m0; /* * Still not there, try the normal collapse * again before we allocate another cluster. */ goto again; } prev = &n->m_next; } /* * No place where we can collapse to a cluster; punt. * This can occur if, for example, you request 2 frags * but the packet requires that both be clusters (we * never reallocate the first mbuf to avoid moving the * packet header). */ bad: return NULL; } #ifdef MBUF_STRESS_TEST /* * Fragment an mbuf chain. There's no reason you'd ever want to do * this in normal usage, but it's great for stress testing various * mbuf consumers. * * If fragmentation is not possible, the original chain will be * returned. * * Possible length values: * 0 no fragmentation will occur * > 0 each fragment will be of the specified length * -1 each fragment will be the same random value in length * -2 each fragment's length will be entirely random * (Random values range from 1 to 256) */ struct mbuf * m_fragment(struct mbuf *m0, int how, int length) { struct mbuf *m_first, *m_last; int divisor = 255, progress = 0, fraglen; if (!(m0->m_flags & M_PKTHDR)) return (m0); if (length == 0 || length < -2) return (m0); if (length > MCLBYTES) length = MCLBYTES; if (length < 0 && divisor > MCLBYTES) divisor = MCLBYTES; if (length == -1) length = 1 + (arc4random() % divisor); if (length > 0) fraglen = length; m_fixhdr(m0); /* Needed sanity check */ m_first = m_getcl(how, MT_DATA, M_PKTHDR); if (m_first == NULL) goto nospace; if (m_dup_pkthdr(m_first, m0, how) == 0) goto nospace; m_last = m_first; while (progress < m0->m_pkthdr.len) { if (length == -2) fraglen = 1 + (arc4random() % divisor); if (fraglen > m0->m_pkthdr.len - progress) fraglen = m0->m_pkthdr.len - progress; if (progress != 0) { struct mbuf *m_new = m_getcl(how, MT_DATA, 0); if (m_new == NULL) goto nospace; m_last->m_next = m_new; m_last = m_new; } m_copydata(m0, progress, fraglen, mtod(m_last, caddr_t)); progress += fraglen; m_last->m_len = fraglen; } m_freem(m0); m0 = m_first; return (m0); nospace: if (m_first) m_freem(m_first); /* Return the original chain on failure */ return (m0); } #endif /* * Free pages from mbuf_ext_pgs, assuming they were allocated via * vm_page_alloc() and aren't associated with any object. Complement * to allocator from m_uiotombuf_nomap(). */ void mb_free_mext_pgs(struct mbuf *m) { vm_page_t pg; M_ASSERTEXTPG(m); for (int i = 0; i < m->m_epg_npgs; i++) { pg = PHYS_TO_VM_PAGE(m->m_epg_pa[i]); vm_page_unwire_noq(pg); vm_page_free(pg); } } static struct mbuf * m_uiotombuf_nomap(struct uio *uio, int how, int len, int maxseg, int flags) { struct mbuf *m, *mb, *prev; vm_page_t pg_array[MBUF_PEXT_MAX_PGS]; int error, length, i, needed; ssize_t total; int pflags = malloc2vm_flags(how) | VM_ALLOC_NOOBJ | VM_ALLOC_NODUMP | VM_ALLOC_WIRED; MPASS((flags & M_PKTHDR) == 0); MPASS((how & M_ZERO) == 0); /* * len can be zero or an arbitrary large value bound by * the total data supplied by the uio. */ if (len > 0) total = MIN(uio->uio_resid, len); else total = uio->uio_resid; if (maxseg == 0) maxseg = MBUF_PEXT_MAX_PGS * PAGE_SIZE; /* * If total is zero, return an empty mbuf. This can occur * for TLS 1.0 connections which send empty fragments as * a countermeasure against the known-IV weakness in CBC * ciphersuites. */ if (__predict_false(total == 0)) { mb = mb_alloc_ext_pgs(how, mb_free_mext_pgs); if (mb == NULL) return (NULL); mb->m_epg_flags = EPG_FLAG_ANON; return (mb); } /* * Allocate the pages */ m = NULL; while (total > 0) { mb = mb_alloc_ext_pgs(how, mb_free_mext_pgs); if (mb == NULL) goto failed; if (m == NULL) m = mb; else prev->m_next = mb; prev = mb; mb->m_epg_flags = EPG_FLAG_ANON; needed = length = MIN(maxseg, total); for (i = 0; needed > 0; i++, needed -= PAGE_SIZE) { retry_page: pg_array[i] = vm_page_alloc(NULL, 0, pflags); if (pg_array[i] == NULL) { if (how & M_NOWAIT) { goto failed; } else { vm_wait(NULL); goto retry_page; } } mb->m_epg_pa[i] = VM_PAGE_TO_PHYS(pg_array[i]); mb->m_epg_npgs++; } mb->m_epg_last_len = length - PAGE_SIZE * (mb->m_epg_npgs - 1); MBUF_EXT_PGS_ASSERT_SANITY(mb); total -= length; error = uiomove_fromphys(pg_array, 0, length, uio); if (error != 0) goto failed; mb->m_len = length; mb->m_ext.ext_size += PAGE_SIZE * mb->m_epg_npgs; if (flags & M_PKTHDR) m->m_pkthdr.len += length; } return (m); failed: m_freem(m); return (NULL); } /* * Copy the contents of uio into a properly sized mbuf chain. */ struct mbuf * m_uiotombuf(struct uio *uio, int how, int len, int align, int flags) { struct mbuf *m, *mb; int error, length; ssize_t total; int progress = 0; if (flags & M_EXTPG) return (m_uiotombuf_nomap(uio, how, len, align, flags)); /* * len can be zero or an arbitrary large value bound by * the total data supplied by the uio. */ if (len > 0) total = (uio->uio_resid < len) ? uio->uio_resid : len; else total = uio->uio_resid; /* * The smallest unit returned by m_getm2() is a single mbuf * with pkthdr. We can't align past it. */ if (align >= MHLEN) return (NULL); /* * Give us the full allocation or nothing. * If len is zero return the smallest empty mbuf. */ m = m_getm2(NULL, max(total + align, 1), how, MT_DATA, flags); if (m == NULL) return (NULL); m->m_data += align; /* Fill all mbufs with uio data and update header information. */ for (mb = m; mb != NULL; mb = mb->m_next) { length = min(M_TRAILINGSPACE(mb), total - progress); error = uiomove(mtod(mb, void *), length, uio); if (error) { m_freem(m); return (NULL); } mb->m_len = length; progress += length; if (flags & M_PKTHDR) m->m_pkthdr.len += length; } KASSERT(progress == total, ("%s: progress != total", __func__)); return (m); } /* * Copy data from an unmapped mbuf into a uio limited by len if set. */ int m_unmappedtouio(const struct mbuf *m, int m_off, struct uio *uio, int len) { vm_page_t pg; int error, i, off, pglen, pgoff, seglen, segoff; M_ASSERTEXTPG(m); error = 0; /* Skip over any data removed from the front. */ off = mtod(m, vm_offset_t); off += m_off; if (m->m_epg_hdrlen != 0) { if (off >= m->m_epg_hdrlen) { off -= m->m_epg_hdrlen; } else { seglen = m->m_epg_hdrlen - off; segoff = off; seglen = min(seglen, len); off = 0; len -= seglen; error = uiomove(__DECONST(void *, &m->m_epg_hdr[segoff]), seglen, uio); } } pgoff = m->m_epg_1st_off; for (i = 0; i < m->m_epg_npgs && error == 0 && len > 0; i++) { pglen = m_epg_pagelen(m, i, pgoff); if (off >= pglen) { off -= pglen; pgoff = 0; continue; } seglen = pglen - off; segoff = pgoff + off; off = 0; seglen = min(seglen, len); len -= seglen; pg = PHYS_TO_VM_PAGE(m->m_epg_pa[i]); error = uiomove_fromphys(&pg, segoff, seglen, uio); pgoff = 0; }; if (len != 0 && error == 0) { KASSERT((off + len) <= m->m_epg_trllen, ("off + len > trail (%d + %d > %d, m_off = %d)", off, len, m->m_epg_trllen, m_off)); error = uiomove(__DECONST(void *, &m->m_epg_trail[off]), len, uio); } return (error); } /* * Copy an mbuf chain into a uio limited by len if set. */ int m_mbuftouio(struct uio *uio, const struct mbuf *m, int len) { int error, length, total; int progress = 0; if (len > 0) total = min(uio->uio_resid, len); else total = uio->uio_resid; /* Fill the uio with data from the mbufs. */ for (; m != NULL; m = m->m_next) { length = min(m->m_len, total - progress); if ((m->m_flags & M_EXTPG) != 0) error = m_unmappedtouio(m, 0, uio, length); else error = uiomove(mtod(m, void *), length, uio); if (error) return (error); progress += length; } return (0); } /* * Create a writable copy of the mbuf chain. While doing this * we compact the chain with a goal of producing a chain with * at most two mbufs. The second mbuf in this chain is likely * to be a cluster. The primary purpose of this work is to create * a writable packet for encryption, compression, etc. The * secondary goal is to linearize the data so the data can be * passed to crypto hardware in the most efficient manner possible. */ struct mbuf * m_unshare(struct mbuf *m0, int how) { struct mbuf *m, *mprev; struct mbuf *n, *mfirst, *mlast; int len, off; mprev = NULL; for (m = m0; m != NULL; m = mprev->m_next) { /* * Regular mbufs are ignored unless there's a cluster * in front of it that we can use to coalesce. We do * the latter mainly so later clusters can be coalesced * also w/o having to handle them specially (i.e. convert * mbuf+cluster -> cluster). This optimization is heavily * influenced by the assumption that we're running over * Ethernet where MCLBYTES is large enough that the max * packet size will permit lots of coalescing into a * single cluster. This in turn permits efficient * crypto operations, especially when using hardware. */ if ((m->m_flags & M_EXT) == 0) { if (mprev && (mprev->m_flags & M_EXT) && m->m_len <= M_TRAILINGSPACE(mprev)) { /* XXX: this ignores mbuf types */ memcpy(mtod(mprev, caddr_t) + mprev->m_len, mtod(m, caddr_t), m->m_len); mprev->m_len += m->m_len; mprev->m_next = m->m_next; /* unlink from chain */ m_free(m); /* reclaim mbuf */ } else { mprev = m; } continue; } /* * Writable mbufs are left alone (for now). */ if (M_WRITABLE(m)) { mprev = m; continue; } /* * Not writable, replace with a copy or coalesce with * the previous mbuf if possible (since we have to copy * it anyway, we try to reduce the number of mbufs and * clusters so that future work is easier). */ KASSERT(m->m_flags & M_EXT, ("m_flags 0x%x", m->m_flags)); /* NB: we only coalesce into a cluster or larger */ if (mprev != NULL && (mprev->m_flags & M_EXT) && m->m_len <= M_TRAILINGSPACE(mprev)) { /* XXX: this ignores mbuf types */ memcpy(mtod(mprev, caddr_t) + mprev->m_len, mtod(m, caddr_t), m->m_len); mprev->m_len += m->m_len; mprev->m_next = m->m_next; /* unlink from chain */ m_free(m); /* reclaim mbuf */ continue; } /* * Allocate new space to hold the copy and copy the data. * We deal with jumbo mbufs (i.e. m_len > MCLBYTES) by * splitting them into clusters. We could just malloc a * buffer and make it external but too many device drivers * don't know how to break up the non-contiguous memory when * doing DMA. */ n = m_getcl(how, m->m_type, m->m_flags & M_COPYFLAGS); if (n == NULL) { m_freem(m0); return (NULL); } if (m->m_flags & M_PKTHDR) { KASSERT(mprev == NULL, ("%s: m0 %p, m %p has M_PKTHDR", __func__, m0, m)); m_move_pkthdr(n, m); } len = m->m_len; off = 0; mfirst = n; mlast = NULL; for (;;) { int cc = min(len, MCLBYTES); memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, cc); n->m_len = cc; if (mlast != NULL) mlast->m_next = n; mlast = n; #if 0 newipsecstat.ips_clcopied++; #endif len -= cc; if (len <= 0) break; off += cc; n = m_getcl(how, m->m_type, m->m_flags & M_COPYFLAGS); if (n == NULL) { m_freem(mfirst); m_freem(m0); return (NULL); } } n->m_next = m->m_next; if (mprev == NULL) m0 = mfirst; /* new head of chain */ else mprev->m_next = mfirst; /* replace old mbuf */ m_free(m); /* release old mbuf */ mprev = mfirst; } return (m0); } #ifdef MBUF_PROFILING #define MP_BUCKETS 32 /* don't just change this as things may overflow.*/ struct mbufprofile { uintmax_t wasted[MP_BUCKETS]; uintmax_t used[MP_BUCKETS]; uintmax_t segments[MP_BUCKETS]; } mbprof; #define MP_MAXDIGITS 21 /* strlen("16,000,000,000,000,000,000") == 21 */ #define MP_NUMLINES 6 #define MP_NUMSPERLINE 16 #define MP_EXTRABYTES 64 /* > strlen("used:\nwasted:\nsegments:\n") */ /* work out max space needed and add a bit of spare space too */ #define MP_MAXLINE ((MP_MAXDIGITS+1) * MP_NUMSPERLINE) #define MP_BUFSIZE ((MP_MAXLINE * MP_NUMLINES) + 1 + MP_EXTRABYTES) char mbprofbuf[MP_BUFSIZE]; void m_profile(struct mbuf *m) { int segments = 0; int used = 0; int wasted = 0; while (m) { segments++; used += m->m_len; if (m->m_flags & M_EXT) { wasted += MHLEN - sizeof(m->m_ext) + m->m_ext.ext_size - m->m_len; } else { if (m->m_flags & M_PKTHDR) wasted += MHLEN - m->m_len; else wasted += MLEN - m->m_len; } m = m->m_next; } /* be paranoid.. it helps */ if (segments > MP_BUCKETS - 1) segments = MP_BUCKETS - 1; if (used > 100000) used = 100000; if (wasted > 100000) wasted = 100000; /* store in the appropriate bucket */ /* don't bother locking. if it's slightly off, so what? */ mbprof.segments[segments]++; mbprof.used[fls(used)]++; mbprof.wasted[fls(wasted)]++; } static void mbprof_textify(void) { int offset; char *c; uint64_t *p; p = &mbprof.wasted[0]; c = mbprofbuf; offset = snprintf(c, MP_MAXLINE + 10, "wasted:\n" "%ju %ju %ju %ju %ju %ju %ju %ju " "%ju %ju %ju %ju %ju %ju %ju %ju\n", p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); #ifdef BIG_ARRAY p = &mbprof.wasted[16]; c += offset; offset = snprintf(c, MP_MAXLINE, "%ju %ju %ju %ju %ju %ju %ju %ju " "%ju %ju %ju %ju %ju %ju %ju %ju\n", p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); #endif p = &mbprof.used[0]; c += offset; offset = snprintf(c, MP_MAXLINE + 10, "used:\n" "%ju %ju %ju %ju %ju %ju %ju %ju " "%ju %ju %ju %ju %ju %ju %ju %ju\n", p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); #ifdef BIG_ARRAY p = &mbprof.used[16]; c += offset; offset = snprintf(c, MP_MAXLINE, "%ju %ju %ju %ju %ju %ju %ju %ju " "%ju %ju %ju %ju %ju %ju %ju %ju\n", p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); #endif p = &mbprof.segments[0]; c += offset; offset = snprintf(c, MP_MAXLINE + 10, "segments:\n" "%ju %ju %ju %ju %ju %ju %ju %ju " "%ju %ju %ju %ju %ju %ju %ju %ju\n", p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); #ifdef BIG_ARRAY p = &mbprof.segments[16]; c += offset; offset = snprintf(c, MP_MAXLINE, "%ju %ju %ju %ju %ju %ju %ju %ju " "%ju %ju %ju %ju %ju %ju %ju %jju", p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]); #endif } static int mbprof_handler(SYSCTL_HANDLER_ARGS) { int error; mbprof_textify(); error = SYSCTL_OUT(req, mbprofbuf, strlen(mbprofbuf) + 1); return (error); } static int mbprof_clr_handler(SYSCTL_HANDLER_ARGS) { int clear, error; clear = 0; error = sysctl_handle_int(oidp, &clear, 0, req); if (error || !req->newptr) return (error); if (clear) { bzero(&mbprof, sizeof(mbprof)); } return (error); } SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofile, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT, NULL, 0, mbprof_handler, "A", "mbuf profiling statistics"); SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofileclr, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0, mbprof_clr_handler, "I", "clear mbuf profiling statistics"); #endif