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3eca04a56b
freebsd-dev/sys/kern/uipc_mbuf.c
Boris Popov 03137ec82e Fix parameter order in the calls to MGET().
2001-02-21 09:24:13 +00:00

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/*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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
* $FreeBSD$
*/
#include "opt_param.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
static void mbinit(void *);
SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL)
struct mbuf *mbutl;
struct mbstat mbstat;
u_long mbtypes[MT_NTYPES];
int max_linkhdr;
int max_protohdr;
int max_hdr;
int max_datalen;
int nmbclusters;
int nmbufs;
int nmbcnt;
u_long m_mballoc_wid = 0;
u_long m_clalloc_wid = 0;
/*
* freelist header structures...
* mbffree_lst, mclfree_lst, mcntfree_lst
*/
struct mbffree_lst mmbfree;
struct mclfree_lst mclfree;
struct mcntfree_lst mcntfree;
/*
* sysctl(8) exported objects
*/
SYSCTL_DECL(_kern_ipc);
SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW,
&max_linkhdr, 0, "");
SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW,
&max_protohdr, 0, "");
SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0, "");
SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW,
&max_datalen, 0, "");
SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_wait, CTLFLAG_RW,
&mbuf_wait, 0, "");
SYSCTL_STRUCT(_kern_ipc, KIPC_MBSTAT, mbstat, CTLFLAG_RD, &mbstat, mbstat, "");
SYSCTL_OPAQUE(_kern_ipc, OID_AUTO, mbtypes, CTLFLAG_RD, mbtypes,
sizeof(mbtypes), "LU", "");
SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters, CTLFLAG_RD,
&nmbclusters, 0, "Maximum number of mbuf clusters available");
SYSCTL_INT(_kern_ipc, OID_AUTO, nmbufs, CTLFLAG_RD, &nmbufs, 0,
"Maximum number of mbufs available");
SYSCTL_INT(_kern_ipc, OID_AUTO, nmbcnt, CTLFLAG_RD, &nmbcnt, 0,
"Maximum number of ext_buf counters available");
#ifndef NMBCLUSTERS
#define NMBCLUSTERS (512 + MAXUSERS * 16)
#endif
TUNABLE_INT_DECL("kern.ipc.nmbclusters", NMBCLUSTERS, nmbclusters);
TUNABLE_INT_DECL("kern.ipc.nmbufs", NMBCLUSTERS * 4, nmbufs);
TUNABLE_INT_DECL("kern.ipc.nmbcnt", EXT_COUNTERS, nmbcnt);
static void m_reclaim(void);
/* Initial allocation numbers */
#define NCL_INIT 2
#define NMB_INIT 16
#define REF_INIT NMBCLUSTERS
/*
* Full mbuf subsystem initialization done here.
*
* XXX: If ever we have system specific map setups to do, then move them to
* machdep.c - for now, there is no reason for this stuff to go there.
*/
static void
mbinit(void *dummy)
{
vm_offset_t maxaddr, mb_map_size;
/*
* Setup the mb_map, allocate requested VM space.
*/
mb_map_size = nmbufs * MSIZE + nmbclusters * MCLBYTES + nmbcnt
* sizeof(union mext_refcnt);
mb_map_size = roundup2(mb_map_size, PAGE_SIZE);
mb_map = kmem_suballoc(kmem_map, (vm_offset_t *)&mbutl, &maxaddr,
mb_map_size);
/* XXX XXX XXX: mb_map->system_map = 1; */
/*
* Initialize the free list headers, and setup locks for lists.
*/
mmbfree.m_head = NULL;
mclfree.m_head = NULL;
mcntfree.m_head = NULL;
mtx_init(&mmbfree.m_mtx, "mbuf free list lock", MTX_DEF);
mtx_init(&mclfree.m_mtx, "mcluster free list lock", MTX_DEF);
mtx_init(&mcntfree.m_mtx, "m_ext counter free list lock", MTX_DEF);
/*
* Initialize mbuf subsystem (sysctl exported) statistics structure.
*/
mbstat.m_msize = MSIZE;
mbstat.m_mclbytes = MCLBYTES;
mbstat.m_minclsize = MINCLSIZE;
mbstat.m_mlen = MLEN;
mbstat.m_mhlen = MHLEN;
/*
* Perform some initial allocations.
*/
mtx_lock(&mcntfree.m_mtx);
if (m_alloc_ref(REF_INIT, M_DONTWAIT) == 0)
goto bad;
mtx_unlock(&mcntfree.m_mtx);
mtx_lock(&mmbfree.m_mtx);
if (m_mballoc(NMB_INIT, M_DONTWAIT) == 0)
goto bad;
mtx_unlock(&mmbfree.m_mtx);
mtx_lock(&mclfree.m_mtx);
if (m_clalloc(NCL_INIT, M_DONTWAIT) == 0)
goto bad;
mtx_unlock(&mclfree.m_mtx);
return;
bad:
panic("mbinit: failed to initialize mbuf subsystem!");
}
/*
* Allocate at least nmb reference count structs and place them
* on the ref cnt free list.
*
* Must be called with the mcntfree lock held.
*/
int
m_alloc_ref(u_int nmb, int how)
{
caddr_t p;
u_int nbytes;
int i;
/*
* We don't cap the amount of memory that can be used
* by the reference counters, like we do for mbufs and
* mbuf clusters. In fact, we're absolutely sure that we
* won't ever be going over our allocated space. We keep enough
* space in mb_map to accomodate maximum values of allocatable
* external buffers including, but not limited to, clusters.
* (That's also why we won't have to have wait routines for
* counters).
*
* If we're in here, we're absolutely certain to be returning
* succesfully, as long as there is physical memory to accomodate
* us. And if there isn't, but we're willing to wait, then
* kmem_malloc() will do the only waiting needed.
*/
nbytes = round_page(nmb * sizeof(union mext_refcnt));
mtx_unlock(&mcntfree.m_mtx);
if ((p = (caddr_t)kmem_malloc(mb_map, nbytes, how == M_TRYWAIT ?
M_WAITOK : M_NOWAIT)) == NULL) {
mtx_lock(&mcntfree.m_mtx);
return (0);
}
nmb = nbytes / sizeof(union mext_refcnt);
/*
* We don't let go of the mutex in order to avoid a race.
* It is up to the caller to let go of the mutex.
*/
mtx_lock(&mcntfree.m_mtx);
for (i = 0; i < nmb; i++) {
((union mext_refcnt *)p)->next_ref = mcntfree.m_head;
mcntfree.m_head = (union mext_refcnt *)p;
p += sizeof(union mext_refcnt);
mbstat.m_refree++;
}
mbstat.m_refcnt += nmb;
return (1);
}
/*
* Allocate at least nmb mbufs and place on mbuf free list.
*
* Must be called with the mmbfree lock held.
*/
int
m_mballoc(int nmb, int how)
{
caddr_t p;
int i;
int nbytes;
/*
* If we've hit the mbuf limit, stop allocating from mb_map.
* Also, once we run out of map space, it will be impossible to
* get any more (nothing is ever freed back to the map).
*/
if (mb_map_full || ((nmb + mbstat.m_mbufs) > nmbufs)) {
/*
* Needs to be atomic as we may be incrementing it
* while holding another mutex, like mclfree. In other
* words, m_drops is not reserved solely for mbufs,
* but is also available for clusters.
*/
atomic_add_long(&mbstat.m_drops, 1);
return (0);
}
nbytes = round_page(nmb * MSIZE);
mtx_unlock(&mmbfree.m_mtx);
p = (caddr_t)kmem_malloc(mb_map, nbytes, M_NOWAIT);
if (p == NULL && how == M_TRYWAIT) {
atomic_add_long(&mbstat.m_wait, 1);
p = (caddr_t)kmem_malloc(mb_map, nbytes, M_WAITOK);
}
mtx_lock(&mmbfree.m_mtx);
/*
* Either the map is now full, or `how' is M_DONTWAIT and there
* are no pages left.
*/
if (p == NULL)
return (0);
nmb = nbytes / MSIZE;
/*
* We don't let go of the mutex in order to avoid a race.
* It is up to the caller to let go of the mutex when done
* with grabbing the mbuf from the free list.
*/
for (i = 0; i < nmb; i++) {
((struct mbuf *)p)->m_next = mmbfree.m_head;
mmbfree.m_head = (struct mbuf *)p;
p += MSIZE;
}
mbstat.m_mbufs += nmb;
mbtypes[MT_FREE] += nmb;
return (1);
}
/*
* Once the mb_map has been exhausted and if the call to the allocation macros
* (or, in some cases, functions) is with M_TRYWAIT, then it is necessary to
* rely solely on reclaimed mbufs.
*
* Here we request for the protocols to free up some resources and, if we
* still cannot get anything, then we wait for an mbuf to be freed for a
* designated (mbuf_wait) time.
*
* Must be called with the mmbfree mutex held.
*/
struct mbuf *
m_mballoc_wait(void)
{
struct mbuf *p = NULL;
/*
* See if we can drain some resources out of the protocols.
* We drop the mmbfree mutex to avoid recursing into it in some of
* the drain routines. Clearly, we're faced with a race here because
* once something is freed during the drain, it may be grabbed right
* from under us by some other thread. But we accept this possibility
* in order to avoid a potentially large lock recursion and, more
* importantly, to avoid a potential lock order reversal which may
* result in deadlock (See comment above m_reclaim()).
*/
mtx_unlock(&mmbfree.m_mtx);
m_reclaim();
mtx_lock(&mmbfree.m_mtx);
_MGET(p, M_DONTWAIT);
if (p == NULL) {
m_mballoc_wid++;
msleep(&m_mballoc_wid, &mmbfree.m_mtx, PVM, "mballc",
mbuf_wait);
m_mballoc_wid--;
/*
* Try again (one last time).
*
* We retry to fetch _even_ if the sleep timed out. This
* is left this way, purposely, in the [unlikely] case
* that an mbuf was freed but the sleep was not awoken
* in time.
*
* If the sleep didn't time out (i.e. we got woken up) then
* we have the lock so we just grab an mbuf, hopefully.
*/
_MGET(p, M_DONTWAIT);
}
/* If we waited and got something... */
if (p != NULL) {
atomic_add_long(&mbstat.m_wait, 1);
if (mmbfree.m_head != NULL)
MBWAKEUP(m_mballoc_wid);
} else
atomic_add_long(&mbstat.m_drops, 1);
return (p);
}
/*
* Allocate some number of mbuf clusters
* and place on cluster free list.
*
* Must be called with the mclfree lock held.
*/
int
m_clalloc(int ncl, int how)
{
caddr_t p;
int i;
int npg;
/*
* If the map is now full (nothing will ever be freed to it).
* If we've hit the mcluster number limit, stop allocating from
* mb_map.
*/
if (mb_map_full || ((ncl + mbstat.m_clusters) > nmbclusters)) {
atomic_add_long(&mbstat.m_drops, 1);
return (0);
}
npg = ncl;
mtx_unlock(&mclfree.m_mtx);
p = (caddr_t)kmem_malloc(mb_map, ctob(npg),
how == M_TRYWAIT ? M_WAITOK : M_NOWAIT);
ncl = ncl * PAGE_SIZE / MCLBYTES;
mtx_lock(&mclfree.m_mtx);
/*
* Either the map is now full, or `how' is M_DONTWAIT and there
* are no pages left.
*/
if (p == NULL) {
atomic_add_long(&mbstat.m_drops, 1);
return (0);
}
/*
* We don't let go of the mutex in order to avoid a race.
*/
for (i = 0; i < ncl; i++) {
((union mcluster *)p)->mcl_next = mclfree.m_head;
mclfree.m_head = (union mcluster *)p;
p += MCLBYTES;
mbstat.m_clfree++;
}
mbstat.m_clusters += ncl;
return (1);
}
/*
* Once the mb_map submap has been exhausted and the allocation is called with
* M_TRYWAIT, we rely on the mclfree list. If nothing is free, we will
* sleep for a designated amount of time (mbuf_wait) or until we're woken up
* due to sudden mcluster availability.
*
* Must be called with the mclfree lock held.
*/
caddr_t
m_clalloc_wait(void)
{
caddr_t p = NULL;
m_clalloc_wid++;
msleep(&m_clalloc_wid, &mclfree.m_mtx, PVM, "mclalc", mbuf_wait);
m_clalloc_wid--;
/*
* Now that we (think) that we've got something, try again.
*/
_MCLALLOC(p, M_DONTWAIT);
/* If we waited and got something ... */
if (p != NULL) {
atomic_add_long(&mbstat.m_wait, 1);
if (mclfree.m_head != NULL)
MBWAKEUP(m_clalloc_wid);
} else
atomic_add_long(&mbstat.m_drops, 1);
return (p);
}
/*
* m_reclaim: drain protocols in hopes to free up some resources...
*
* XXX: No locks should be held going in here. The drain routines have
* to presently acquire some locks which raises the possibility of lock
* order violation if we're holding any mutex if that mutex is acquired in
* reverse order relative to one of the locks in the drain routines.
*/
static void
m_reclaim(void)
{
struct domain *dp;
struct protosw *pr;
#ifdef WITNESS
KASSERT(witness_list(CURPROC) == 0,
("m_reclaim called with locks held"));
#endif
for (dp = domains; dp; dp = dp->dom_next)
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
if (pr->pr_drain)
(*pr->pr_drain)();
mbstat.m_drain++;
}
/*
* Space allocation routines.
* Some of these are also available as macros
* for critical paths.
*/
struct mbuf *
m_get(int how, int type)
{
struct mbuf *m;
MGET(m, how, type);
return (m);
}
struct mbuf *
m_gethdr(int how, int type)
{
struct mbuf *m;
MGETHDR(m, how, type);
return (m);
}
struct mbuf *
m_getclr(int how, int type)
{
struct mbuf *m;
MGET(m, how, type);
if (m == NULL)
return (NULL);
bzero(mtod(m, caddr_t), MLEN);
return (m);
}
struct mbuf *
m_free(struct mbuf *m)
{
struct mbuf *n;
MFREE(m, n);
return (n);
}
/*
* struct mbuf *
* m_getm(m, len, how, type)
*
* This will allocate len-worth of mbufs and/or mbuf clusters (whatever fits
* best) and return a pointer to the top of the allocated chain. If m is
* non-null, then we assume that it is a single mbuf or an mbuf chain to
* which we want len bytes worth of mbufs and/or clusters attached, and so
* if we succeed in allocating it, we will just return a pointer to m.
*
* If we happen to fail at any point during the allocation, we will free
* up everything we have already allocated and return NULL.
*
*/
struct mbuf *
m_getm(struct mbuf *m, int len, int how, int type)
{
struct mbuf *top, *tail, *mp, *mtail = NULL;
KASSERT(len >= 0, ("len is < 0 in m_getm"));
MGET(mp, how, type);
if (mp == NULL)
return (NULL);
else if (len > MINCLSIZE) {
MCLGET(mp, how);
if ((mp->m_flags & M_EXT) == 0) {
m_free(mp);
return (NULL);
}
}
mp->m_len = 0;
len -= M_TRAILINGSPACE(mp);
if (m != NULL)
for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next);
else
m = mp;
top = tail = mp;
while (len > 0) {
MGET(mp, how, type);
if (mp == NULL)
goto failed;
tail->m_next = mp;
tail = mp;
if (len > MINCLSIZE) {
MCLGET(mp, how);
if ((mp->m_flags & M_EXT) == 0)
goto failed;
}
mp->m_len = 0;
len -= M_TRAILINGSPACE(mp);
}
if (mtail != NULL)
mtail->m_next = top;
return (m);
failed:
m_freem(top);
return (NULL);
}
void
m_freem(struct mbuf *m)
{
struct mbuf *n;
if (m == NULL)
return;
do {
/*
* we do need to check non-first mbuf, since some of existing
* code does not call M_PREPEND properly.
* (example: call to bpf_mtap from drivers)
*/
if ((m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.aux) {
m_freem(m->m_pkthdr.aux);
m->m_pkthdr.aux = NULL;
}
MFREE(m, n);
m = n;
} while (m);
}
/*
* 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;
MGET(mn, how, m->m_type);
if (mn == NULL) {
m_freem(m);
return (NULL);
}
if (m->m_flags & M_PKTHDR) {
M_COPY_PKTHDR(mn, m);
m->m_flags &= ~M_PKTHDR;
}
mn->m_next = m;
m = mn;
if (len < MHLEN)
MH_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_TRYWAIT/M_DONTWAIT from caller.
* Note that the copy is read-only, because clusters are not copied,
* only their reference counts are incremented.
*/
#define MCFail (mbstat.m_mcfail)
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));
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;
top = 0;
while (len > 0) {
if (m == NULL) {
KASSERT(len == M_COPYALL,
("m_copym, length > size of mbuf chain"));
break;
}
MGET(n, wait, m->m_type);
*np = n;
if (n == NULL)
goto nospace;
if (copyhdr) {
M_COPY_PKTHDR(n, m);
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) {
n->m_data = m->m_data + off;
n->m_ext = m->m_ext;
n->m_flags |= M_EXT;
MEXT_ADD_REF(m);
} else
bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
(unsigned)n->m_len);
if (len != M_COPYALL)
len -= n->m_len;
off = 0;
m = m->m_next;
np = &n->m_next;
}
if (top == NULL)
atomic_add_long(&MCFail, 1);
return (top);
nospace:
m_freem(top);
atomic_add_long(&MCFail, 1);
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;
MGET(n, how, m->m_type);
top = n;
if (n == NULL)
goto nospace;
M_COPY_PKTHDR(n, m);
n->m_len = m->m_len;
if (m->m_flags & M_EXT) {
n->m_data = m->m_data;
n->m_ext = m->m_ext;
n->m_flags |= M_EXT;
MEXT_ADD_REF(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) {
MGET(o, 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) {
n->m_data = m->m_data;
n->m_ext = m->m_ext;
n->m_flags |= M_EXT;
MEXT_ADD_REF(m);
} else {
bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
}
m = m->m_next;
}
return top;
nospace:
m_freem(top);
atomic_add_long(&MCFail, 1);
return (NULL);
}
/*
* Copy data from an mbuf chain starting "off" bytes from the beginning,
* continuing for "len" bytes, into the indicated buffer.
*/
void
m_copydata(struct mbuf *m, int off, int len, caddr_t cp)
{
unsigned 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);
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(struct mbuf *m, int how)
{
struct mbuf **p, *top = NULL;
int remain, moff, nsize;
/* Sanity check */
if (m == NULL)
return (NULL);
KASSERT((m->m_flags & M_PKTHDR) != 0, ("%s: !PKTHDR", __FUNCTION__));
/* While there's more data, get a new mbuf, tack it on, and fill it */
remain = m->m_pkthdr.len;
moff = 0;
p = &top;
while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */
struct mbuf *n;
/* Get the next new mbuf */
MGET(n, how, m->m_type);
if (n == NULL)
goto nospace;
if (top == NULL) { /* first one, must be PKTHDR */
M_COPY_PKTHDR(n, m);
nsize = MHLEN;
} else /* not the first one */
nsize = MLEN;
if (remain >= MINCLSIZE) {
MCLGET(n, how);
if ((n->m_flags & M_EXT) == 0) {
(void)m_free(n);
goto nospace;
}
nsize = MCLBYTES;
}
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", __FUNCTION__));
}
return (top);
nospace:
m_freem(top);
atomic_add_long(&MCFail, 1);
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->m_flags & M_EXT ||
m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) {
/* 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);
}
}
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;
}
}
m = mp;
if (mp->m_flags & M_PKTHDR)
m->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;
break;
}
count -= m->m_len;
}
while (m->m_next)
(m = m->m_next) ->m_len = 0;
}
}
/*
* Rearange an mbuf chain so that len bytes are contiguous
* and in the data area of an mbuf (so that mtod and dtom
* 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.
*/
#define MPFail (mbstat.m_mpfail)
struct mbuf *
m_pullup(struct mbuf *n, int len)
{
struct mbuf *m;
int count;
int space;
/*
* 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;
MGET(m, M_DONTWAIT, n->m_type);
if (m == NULL)
goto bad;
m->m_len = 0;
if (n->m_flags & M_PKTHDR) {
M_COPY_PKTHDR(m, n);
n->m_flags &= ~M_PKTHDR;
}
}
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,
(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);
atomic_add_long(&MPFail, 1);
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.
*/
struct mbuf *
m_split(struct mbuf *m0, int len0, int wait)
{
struct mbuf *m, *n;
unsigned len = len0, remain;
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) {
MGETHDR(n, wait, m0->m_type);
if (n == NULL)
return (NULL);
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)
goto extpacket;
if (remain > MHLEN) {
/* m can't be the lead packet */
MH_ALIGN(n, 0);
n->m_next = m_split(m, len, wait);
if (n->m_next == NULL) {
(void) m_free(n);
return (NULL);
} else
return (n);
} else
MH_ALIGN(n, remain);
} else if (remain == 0) {
n = m->m_next;
m->m_next = NULL;
return (n);
} else {
MGET(n, wait, m->m_type);
if (n == NULL)
return (NULL);
M_ALIGN(n, remain);
}
extpacket:
if (m->m_flags & M_EXT) {
n->m_flags |= M_EXT;
n->m_ext = m->m_ext;
MEXT_ADD_REF(m);
m->m_ext.ext_size = 0; /* For Accounting XXXXXX danger */
n->m_data = m->m_data + len;
} 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.
*/
struct mbuf *
m_devget(char *buf, int totlen, int off0, struct ifnet *ifp,
void (*copy)(char *from, caddr_t to, u_int len))
{
struct mbuf *m;
struct mbuf *top = 0, **mp = &top;
int off = off0, len;
char *cp;
char *epkt;
cp = buf;
epkt = cp + totlen;
if (off) {
cp += off + 2 * sizeof(u_short);
totlen -= 2 * sizeof(u_short);
}
MGETHDR(m, M_DONTWAIT, MT_DATA);
if (m == NULL)
return (NULL);
m->m_pkthdr.rcvif = ifp;
m->m_pkthdr.len = totlen;
m->m_len = MHLEN;
while (totlen > 0) {
if (top) {
MGET(m, M_DONTWAIT, MT_DATA);
if (m == NULL) {
m_freem(top);
return (NULL);
}
m->m_len = MLEN;
}
len = min(totlen, epkt - cp);
if (len >= MINCLSIZE) {
MCLGET(m, M_DONTWAIT);
if (m->m_flags & M_EXT)
m->m_len = len = min(len, MCLBYTES);
else
len = m->m_len;
} else {
/*
* Place initial small packet/header at end of mbuf.
*/
if (len < m->m_len) {
if (top == NULL && len +
max_linkhdr <= m->m_len)
m->m_data += max_linkhdr;
m->m_len = len;
} else
len = m->m_len;
}
if (copy)
copy(cp, mtod(m, caddr_t), (unsigned)len);
else
bcopy(cp, mtod(m, caddr_t), (unsigned)len);
cp += len;
*mp = m;
mp = &m->m_next;
totlen -= len;
if (cp == epkt)
cp = buf;
}
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, 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_getclr(M_DONTWAIT, m->m_type);
if (n == NULL)
goto out;
n->m_len = min(MLEN, len + off);
m->m_next = n;
}
m = m->m_next;
}
while (len > 0) {
mlen = min (m->m_len - off, len);
bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen);
cp += mlen;
len -= mlen;
mlen += off;
off = 0;
totlen += mlen;
if (len == 0)
break;
if (m->m_next == NULL) {
n = m_get(M_DONTWAIT, 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;
}
void
m_print(const struct mbuf *m)
{
int len;
const struct mbuf *m2;
len = m->m_pkthdr.len;
m2 = m;
while (len) {
printf("%p %*D\n", m2, m2->m_len, (u_char *)m2->m_data, "-");
len -= m2->m_len;
m2 = m2->m_next;
}
return;
}
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