/*-
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_param.h"
#include "opt_mbuf_stress_test.h"
#include "opt_mbuf_profiling.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/sysctl.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/uio.h>
#include <sys/vmmeter.h>
#include <sys/sdt.h>
#include <vm/vm.h>
#include <vm/vm_pageout.h>
#include <vm/vm_page.h>
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 <security/mac/mac_framework.h>
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);
/*
* 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;
}
}
pg_array[i]->flags &= ~PG_ZERO;
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