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NetBSD/sys/kern/uipc_mbuf.c
yamt 6b2d8b66a4 merge yamt-km branch. 
- don't use managed mappings/backing objects for wired memory allocations.
  save some resources like pv_entry.  also fix (most of) PR/27030.
- simplify kernel memory management API.
- simplify pmap bootstrap of some ports.
- some related cleanups.
2005-04-01 11:59:21 +00:00

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/* uipc_mbuf.c,v 1.84 2004/07/21 12:06:46 yamt Exp */
/*-
* Copyright (c) 1999, 2001 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center.
*
* 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 NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
* 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 8.4 (Berkeley) 2/14/95
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "uipc_mbuf.c,v 1.84 2004/07/21 12:06:46 yamt Exp");
#include "opt_mbuftrace.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#define MBTYPES
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/pool.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <uvm/uvm.h>
struct pool mbpool; /* mbuf pool */
struct pool mclpool; /* mbuf cluster pool */
struct pool_cache mbpool_cache;
struct pool_cache mclpool_cache;
struct mbstat mbstat;
int max_linkhdr;
int max_protohdr;
int max_hdr;
int max_datalen;
static int mb_ctor(void *, void *, int);
void *mclpool_alloc(struct pool *, int);
void mclpool_release(struct pool *, void *);
struct pool_allocator mclpool_allocator = {
mclpool_alloc, mclpool_release, 0,
};
static struct mbuf *m_copym0(struct mbuf *, int, int, int, int);
static struct mbuf *m_split0(struct mbuf *, int, int, int);
static int m_copyback0(struct mbuf **, int, int, const void *, int, int);
/* flags for m_copyback0 */
#define M_COPYBACK0_COPYBACK 0x0001 /* copyback from cp */
#define M_COPYBACK0_PRESERVE 0x0002 /* preserve original data */
#define M_COPYBACK0_COW 0x0004 /* do copy-on-write */
#define M_COPYBACK0_EXTEND 0x0008 /* extend chain */
const char mclpool_warnmsg[] =
"WARNING: mclpool limit reached; increase NMBCLUSTERS";
MALLOC_DEFINE(M_MBUF, "mbuf", "mbuf");
#ifdef MBUFTRACE
struct mownerhead mowners = LIST_HEAD_INITIALIZER(mowners);
struct mowner unknown_mowners[] = {
{ "unknown", "free" },
{ "unknown", "data" },
{ "unknown", "header" },
{ "unknown", "soname" },
{ "unknown", "soopts" },
{ "unknown", "ftable" },
{ "unknown", "control" },
{ "unknown", "oobdata" },
};
struct mowner revoked_mowner = { "revoked", "" };
#endif
/*
* Initialize the mbuf allocator.
*/
void
mbinit(void)
{
KASSERT(sizeof(struct _m_ext) <= MHLEN);
KASSERT(sizeof(struct mbuf) == MSIZE);
pool_init(&mbpool, msize, 0, 0, 0, "mbpl", NULL);
pool_init(&mclpool, mclbytes, 0, 0, 0, "mclpl", &mclpool_allocator);
pool_set_drain_hook(&mbpool, m_reclaim, NULL);
pool_set_drain_hook(&mclpool, m_reclaim, NULL);
pool_cache_init(&mbpool_cache, &mbpool, mb_ctor, NULL, NULL);
pool_cache_init(&mclpool_cache, &mclpool, NULL, NULL, NULL);
/*
* Set the hard limit on the mclpool to the number of
* mbuf clusters the kernel is to support. Log the limit
* reached message max once a minute.
*/
pool_sethardlimit(&mclpool, nmbclusters, mclpool_warnmsg, 60);
/*
* Set a low water mark for both mbufs and clusters. This should
* help ensure that they can be allocated in a memory starvation
* situation. This is important for e.g. diskless systems which
* must allocate mbufs in order for the pagedaemon to clean pages.
*/
pool_setlowat(&mbpool, mblowat);
pool_setlowat(&mclpool, mcllowat);
#ifdef MBUFTRACE
{
/*
* Attach the unknown mowners.
*/
int i;
MOWNER_ATTACH(&revoked_mowner);
for (i = sizeof(unknown_mowners)/sizeof(unknown_mowners[0]);
i-- > 0; )
MOWNER_ATTACH(&unknown_mowners[i]);
}
#endif
}
/*
* sysctl helper routine for the kern.mbuf subtree. nmbclusters may
* or may not be writable, and mblowat and mcllowat need range
* checking and pool tweaking after being reset.
*/
static int
sysctl_kern_mbuf(SYSCTLFN_ARGS)
{
int error, newval;
struct sysctlnode node;
node = *rnode;
node.sysctl_data = &newval;
switch (rnode->sysctl_num) {
case MBUF_NMBCLUSTERS:
if (mb_map != NULL) {
node.sysctl_flags &= ~CTLFLAG_READWRITE;
node.sysctl_flags |= CTLFLAG_READONLY;
}
/* FALLTHROUGH */
case MBUF_MBLOWAT:
case MBUF_MCLLOWAT:
newval = *(int*)rnode->sysctl_data;
break;
default:
return (EOPNOTSUPP);
}
error = sysctl_lookup(SYSCTLFN_CALL(&node));
if (error || newp == NULL)
return (error);
if (newval < 0)
return (EINVAL);
switch (node.sysctl_num) {
case MBUF_NMBCLUSTERS:
if (newval < nmbclusters)
return (EINVAL);
nmbclusters = newval;
pool_sethardlimit(&mclpool, nmbclusters, mclpool_warnmsg, 60);
break;
case MBUF_MBLOWAT:
mblowat = newval;
pool_setlowat(&mbpool, mblowat);
break;
case MBUF_MCLLOWAT:
mcllowat = newval;
pool_setlowat(&mclpool, mcllowat);
break;
}
return (0);
}
#ifdef MBUFTRACE
static int
sysctl_kern_mbuf_mowners(SYSCTLFN_ARGS)
{
struct mowner *mo;
size_t len = 0;
int error = 0;
if (namelen != 0)
return (EINVAL);
if (newp != NULL)
return (EPERM);
LIST_FOREACH(mo, &mowners, mo_link) {
if (oldp != NULL) {
if (*oldlenp - len < sizeof(*mo)) {
error = ENOMEM;
break;
}
error = copyout(mo, (caddr_t) oldp + len,
sizeof(*mo));
if (error)
break;
}
len += sizeof(*mo);
}
if (error == 0)
*oldlenp = len;
return (error);
}
#endif /* MBUFTRACE */
SYSCTL_SETUP(sysctl_kern_mbuf_setup, "sysctl kern.mbuf subtree setup")
{
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "kern", NULL,
NULL, 0, NULL, 0,
CTL_KERN, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "mbuf",
SYSCTL_DESCR("mbuf control variables"),
NULL, 0, NULL, 0,
CTL_KERN, KERN_MBUF, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_IMMEDIATE,
CTLTYPE_INT, "msize",
SYSCTL_DESCR("mbuf base size"),
NULL, msize, NULL, 0,
CTL_KERN, KERN_MBUF, MBUF_MSIZE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_IMMEDIATE,
CTLTYPE_INT, "mclbytes",
SYSCTL_DESCR("mbuf cluster size"),
NULL, mclbytes, NULL, 0,
CTL_KERN, KERN_MBUF, MBUF_MCLBYTES, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "nmbclusters",
SYSCTL_DESCR("Limit on the number of mbuf clusters"),
sysctl_kern_mbuf, 0, &nmbclusters, 0,
CTL_KERN, KERN_MBUF, MBUF_NMBCLUSTERS, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "mblowat",
SYSCTL_DESCR("mbuf low water mark"),
sysctl_kern_mbuf, 0, &mblowat, 0,
CTL_KERN, KERN_MBUF, MBUF_MBLOWAT, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "mcllowat",
SYSCTL_DESCR("mbuf cluster low water mark"),
sysctl_kern_mbuf, 0, &mcllowat, 0,
CTL_KERN, KERN_MBUF, MBUF_MCLLOWAT, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_STRUCT, "stats",
SYSCTL_DESCR("mbuf allocation statistics"),
NULL, 0, &mbstat, sizeof(mbstat),
CTL_KERN, KERN_MBUF, MBUF_STATS, CTL_EOL);
#ifdef MBUFTRACE
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_STRUCT, "mowners",
SYSCTL_DESCR("Information about mbuf owners"),
sysctl_kern_mbuf_mowners, 0, NULL, 0,
CTL_KERN, KERN_MBUF, MBUF_MOWNERS, CTL_EOL);
#endif /* MBUFTRACE */
}
void *
mclpool_alloc(struct pool *pp, int flags)
{
boolean_t waitok = (flags & PR_WAITOK) ? TRUE : FALSE;
return ((void *)uvm_km_alloc_poolpage(mb_map, waitok));
}
void
mclpool_release(struct pool *pp, void *v)
{
uvm_km_free_poolpage(mb_map, (vaddr_t)v);
}
/*ARGSUSED*/
static int
mb_ctor(void *arg, void *object, int flags)
{
struct mbuf *m = object;
#ifdef POOL_VTOPHYS
m->m_paddr = POOL_VTOPHYS(m);
#else
m->m_paddr = M_PADDR_INVALID;
#endif
return (0);
}
void
m_reclaim(void *arg, int flags)
{
struct domain *dp;
const struct protosw *pr;
struct ifnet *ifp;
int s = splvm();
DOMAIN_FOREACH(dp) {
for (pr = dp->dom_protosw;
pr < dp->dom_protoswNPROTOSW; pr++)
if (pr->pr_drain)
(*pr->pr_drain)();
}
IFNET_FOREACH(ifp) {
if (ifp->if_drain)
(*ifp->if_drain)(ifp);
}
splx(s);
mbstat.m_drain++;
}
/*
* Space allocation routines.
* These are also available as macros
* for critical paths.
*/
struct mbuf *
m_get(int nowait, int type)
{
struct mbuf *m;
MGET(m, nowait, type);
return (m);
}
struct mbuf *
m_gethdr(int nowait, int type)
{
struct mbuf *m;
MGETHDR(m, nowait, type);
return (m);
}
struct mbuf *
m_getclr(int nowait, int type)
{
struct mbuf *m;
MGET(m, nowait, type);
if (m == 0)
return (NULL);
memset(mtod(m, caddr_t), 0, MLEN);
return (m);
}
void
m_clget(struct mbuf *m, int nowait)
{
MCLGET(m, nowait);
}
struct mbuf *
m_free(struct mbuf *m)
{
struct mbuf *n;
MFREE(m, n);
return (n);
}
void
m_freem(struct mbuf *m)
{
struct mbuf *n;
if (m == NULL)
return;
do {
MFREE(m, n);
m = n;
} while (m);
}
#ifdef MBUFTRACE
/*
* Walk a chain of mbufs, claiming ownership of each mbuf in the chain.
*/
void
m_claimm(struct mbuf *m, struct mowner *mo)
{
for (; m != NULL; m = m->m_next)
MCLAIM(m, mo);
}
#endif
/*
* Mbuffer utility routines.
*/
/*
* 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 == (struct mbuf *)NULL) {
m_freem(m);
return ((struct mbuf *)NULL);
}
if (m->m_flags & M_PKTHDR) {
M_COPY_PKTHDR(mn, m);
m_tag_delete_chain(m, NULL);
m->m_flags &= ~M_PKTHDR;
} else {
MCLAIM(mn, m->m_owner);
}
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_WAIT/M_DONTWAIT from caller.
*/
int MCFail;
struct mbuf *
m_copym(struct mbuf *m, int off0, int len, int wait)
{
return m_copym0(m, off0, len, wait, 0); /* shallow copy on M_EXT */
}
struct mbuf *
m_dup(struct mbuf *m, int off0, int len, int wait)
{
return m_copym0(m, off0, len, wait, 1); /* deep copy */
}
static struct mbuf *
m_copym0(struct mbuf *m, int off0, int len, int wait, int deep)
{
struct mbuf *n, **np;
int off = off0;
struct mbuf *top;
int copyhdr = 0;
if (off < 0 || len < 0)
panic("m_copym: off %d, len %d", off, len);
if (off == 0 && m->m_flags & M_PKTHDR)
copyhdr = 1;
while (off > 0) {
if (m == 0)
panic("m_copym: m == 0, off %d", off);
if (off < m->m_len)
break;
off -= m->m_len;
m = m->m_next;
}
np = &top;
top = 0;
while (len > 0) {
if (m == 0) {
if (len != M_COPYALL)
panic("m_copym: m == 0, len %d [!COPYALL]",
len);
break;
}
MGET(n, wait, m->m_type);
*np = n;
if (n == 0)
goto nospace;
MCLAIM(n, m->m_owner);
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) {
if (!deep) {
n->m_data = m->m_data + off;
n->m_ext = m->m_ext;
MCLADDREFERENCE(m, n);
} else {
/*
* we are unsure about the way m was allocated.
* copy into multiple MCLBYTES cluster mbufs.
*/
MCLGET(n, wait);
n->m_len = 0;
n->m_len = M_TRAILINGSPACE(n);
n->m_len = min(n->m_len, len);
n->m_len = min(n->m_len, m->m_len - off);
memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off,
(unsigned)n->m_len);
}
} else
memcpy(mtod(n, caddr_t), mtod(m, caddr_t)+off,
(unsigned)n->m_len);
if (len != M_COPYALL)
len -= n->m_len;
off += n->m_len;
#ifdef DIAGNOSTIC
if (off > m->m_len)
panic("m_copym0 overrun");
#endif
if (off == m->m_len) {
m = m->m_next;
off = 0;
}
np = &n->m_next;
}
if (top == 0)
MCFail++;
return (top);
nospace:
m_freem(top);
MCFail++;
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)'.
*/
struct mbuf *
m_copypacket(struct mbuf *m, int how)
{
struct mbuf *top, *n, *o;
MGET(n, how, m->m_type);
top = n;
if (!n)
goto nospace;
MCLAIM(n, m->m_owner);
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;
MCLADDREFERENCE(m, n);
} else {
memcpy(mtod(n, char *), mtod(m, char *), n->m_len);
}
m = m->m_next;
while (m) {
MGET(o, how, m->m_type);
if (!o)
goto nospace;
MCLAIM(o, m->m_owner);
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;
MCLADDREFERENCE(m, n);
} else {
memcpy(mtod(n, char *), mtod(m, char *), n->m_len);
}
m = m->m_next;
}
return top;
nospace:
m_freem(top);
MCFail++;
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, void *vp)
{
unsigned count;
char *cp = vp;
if (off < 0 || len < 0)
panic("m_copydata: off %d, len %d", off, len);
while (off > 0) {
if (m == 0)
panic("m_copydata: m == 0, off %d", off);
if (off < m->m_len)
break;
off -= m->m_len;
m = m->m_next;
}
while (len > 0) {
if (m == 0)
panic("m_copydata: m == 0, len %d", len);
count = min(m->m_len - off, len);
memcpy(cp, mtod(m, caddr_t) + off, count);
len -= count;
cp += count;
off = 0;
m = m->m_next;
}
}
/*
* Concatenate mbuf chain n to m.
* n might be copied into m (when n->m_len is small), therefore data portion of
* n could be copied into an mbuf of different mbuf type.
* 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_READONLY(m) || n->m_len > M_TRAILINGSPACE(m)) {
/* just join the two chains */
m->m_next = n;
return;
}
/* splat the data from one into the other */
memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t),
(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.
*/
int 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 == 0)
goto bad;
MCLAIM(m, n->m_owner);
m->m_len = 0;
if (n->m_flags & M_PKTHDR) {
M_COPY_PKTHDR(m, n);
m_tag_delete_chain(n, NULL);
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);
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);
MPFail++;
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).
*/
int MSFail;
struct mbuf *
m_copyup(struct mbuf *n, int len, int dstoff)
{
struct mbuf *m;
int count, space;
if (len > (MHLEN - dstoff))
goto bad;
MGET(m, M_DONTWAIT, n->m_type);
if (m == NULL)
goto bad;
MCLAIM(m, n->m_owner);
m->m_len = 0;
if (n->m_flags & M_PKTHDR) {
M_COPY_PKTHDR(m, n);
m_tag_delete_chain(n, NULL);
n->m_flags &= ~M_PKTHDR;
}
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);
MSFail++;
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)
{
return m_split0(m0, len0, wait, 1);
}
static struct mbuf *
m_split0(struct mbuf *m0, int len0, int wait, int copyhdr)
{
struct mbuf *m, *n;
unsigned len = len0, remain, len_save;
for (m = m0; m && len > m->m_len; m = m->m_next)
len -= m->m_len;
if (m == 0)
return (NULL);
remain = m->m_len - len;
if (copyhdr && (m0->m_flags & M_PKTHDR)) {
MGETHDR(n, wait, m0->m_type);
if (n == 0)
return (NULL);
MCLAIM(m, m0->m_owner);
n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
n->m_pkthdr.len = m0->m_pkthdr.len - len0;
len_save = m0->m_pkthdr.len;
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 == 0) {
(void) m_free(n);
m0->m_pkthdr.len = len_save;
return (NULL);
} else
return (n);
} else
MH_ALIGN(n, remain);
} else if (remain == 0) {
n = m->m_next;
m->m_next = 0;
return (n);
} else {
MGET(n, wait, m->m_type);
if (n == 0)
return (NULL);
MCLAIM(n, m->m_owner);
M_ALIGN(n, remain);
}
extpacket:
if (m->m_flags & M_EXT) {
n->m_ext = m->m_ext;
MCLADDREFERENCE(m, n);
n->m_data = m->m_data + len;
} else {
memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + len, remain);
}
n->m_len = remain;
m->m_len = len;
n->m_next = m->m_next;
m->m_next = 0;
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)(const void *from, void *to, size_t 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) {
/*
* If 'off' is non-zero, packet is trailer-encapsulated,
* so we have to skip the type and length fields.
*/
cp += off + 2 * sizeof(u_int16_t);
totlen -= 2 * sizeof(u_int16_t);
}
MGETHDR(m, M_DONTWAIT, MT_DATA);
if (m == 0)
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 == 0) {
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) == 0) {
m_free(m);
m_freem(top);
return (NULL);
}
m->m_len = len = min(len, MCLBYTES);
} else {
/*
* Place initial small packet/header at end of mbuf.
*/
if (len < m->m_len) {
if (top == 0 && 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), (size_t)len);
else
memcpy(mtod(m, caddr_t), cp, (size_t)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, const void *cp)
{
#if defined(DEBUG)
struct mbuf *origm = m0;
int error;
#endif /* defined(DEBUG) */
if (m0 == NULL)
return;
#if defined(DEBUG)
error =
#endif /* defined(DEBUG) */
m_copyback0(&m0, off, len, cp,
M_COPYBACK0_COPYBACK|M_COPYBACK0_EXTEND, M_DONTWAIT);
#if defined(DEBUG)
if (error != 0 || (m0 != NULL && origm != m0))
panic("m_copyback");
#endif /* defined(DEBUG) */
}
struct mbuf *
m_copyback_cow(struct mbuf *m0, int off, int len, const void *cp, int how)
{
int error;
/* don't support chain expansion */
KDASSERT(off + len <= m_length(m0));
error = m_copyback0(&m0, off, len, cp,
M_COPYBACK0_COPYBACK|M_COPYBACK0_COW, how);
if (error) {
/*
* no way to recover from partial success.
* just free the chain.
*/
m_freem(m0);
return NULL;
}
return m0;
}
/*
* m_makewritable: ensure the specified range writable.
*/
int
m_makewritable(struct mbuf **mp, int off, int len, int how)
{
int error;
#if defined(DEBUG)
struct mbuf *n;
int origlen, reslen;
origlen = m_length(*mp);
#endif /* defined(DEBUG) */
#if 0 /* M_COPYALL is large enough */
if (len == M_COPYALL)
len = m_length(*mp) - off; /* XXX */
#endif
error = m_copyback0(mp, off, len, NULL,
M_COPYBACK0_PRESERVE|M_COPYBACK0_COW, how);
#if defined(DEBUG)
reslen = 0;
for (n = *mp; n; n = n->m_next)
reslen += n->m_len;
if (origlen != reslen)
panic("m_makewritable: length changed");
if (((*mp)->m_flags & M_PKTHDR) != 0 && reslen != (*mp)->m_pkthdr.len)
panic("m_makewritable: inconsist");
#endif /* defined(DEBUG) */
return error;
}
int
m_copyback0(struct mbuf **mp0, int off, int len, const void *vp, int flags,
int how)
{
int mlen;
struct mbuf *m, *n;
struct mbuf **mp;
int totlen = 0;
const char *cp = vp;
KASSERT(mp0 != NULL);
KASSERT(*mp0 != NULL);
KASSERT((flags & M_COPYBACK0_PRESERVE) == 0 || cp == NULL);
KASSERT((flags & M_COPYBACK0_COPYBACK) == 0 || cp != NULL);
mp = mp0;
m = *mp;
while (off > (mlen = m->m_len)) {
off -= mlen;
totlen += mlen;
if (m->m_next == 0) {
if ((flags & M_COPYBACK0_EXTEND) == 0)
goto out;
n = m_getclr(how, m->m_type);
if (n == 0)
goto out;
n->m_len = min(MLEN, len + off);
m->m_next = n;
}
mp = &m->m_next;
m = m->m_next;
}
while (len > 0) {
mlen = m->m_len - off;
if (mlen != 0 && M_READONLY(m)) {
char *datap;
int eatlen;
/*
* this mbuf is read-only.
* allocate a new writable mbuf and try again.
*/
#if defined(DIAGNOSTIC)
if ((flags & M_COPYBACK0_COW) == 0)
panic("m_copyback0: read-only");
#endif /* defined(DIAGNOSTIC) */
/*
* if we're going to write into the middle of
* a mbuf, split it first.
*/
if (off > 0 && len < mlen) {
n = m_split0(m, off, how, 0);
if (n == NULL)
goto enobufs;
m->m_next = n;
mp = &m->m_next;
m = n;
off = 0;
continue;
}
/*
* XXX TODO coalesce into the trailingspace of
* the previous mbuf when possible.
*/
/*
* allocate a new mbuf. copy packet header if needed.
*/
MGET(n, how, m->m_type);
if (n == NULL)
goto enobufs;
MCLAIM(n, m->m_owner);
if (off == 0 && (m->m_flags & M_PKTHDR) != 0) {
/* XXX M_MOVE_PKTHDR */
M_COPY_PKTHDR(n, m);
n->m_len = MHLEN;
} else {
if (len >= MINCLSIZE)
MCLGET(n, M_DONTWAIT);
n->m_len =
(n->m_flags & M_EXT) ? MCLBYTES : MLEN;
}
if (n->m_len > len)
n->m_len = len;
/*
* free the region which has been overwritten.
* copying data from old mbufs if requested.
*/
if (flags & M_COPYBACK0_PRESERVE)
datap = mtod(n, char *);
else
datap = NULL;
eatlen = n->m_len;
KDASSERT(off == 0 || eatlen >= mlen);
if (off > 0) {
KDASSERT(len >= mlen);
m->m_len = off;
m->m_next = n;
if (datap) {
m_copydata(m, off, mlen, datap);
datap += mlen;
}
eatlen -= mlen;
mp = &m->m_next;
m = m->m_next;
}
while (m != NULL && M_READONLY(m) &&
n->m_type == m->m_type && eatlen > 0) {
mlen = min(eatlen, m->m_len);
if (datap) {
m_copydata(m, 0, mlen, datap);
datap += mlen;
}
m->m_data += mlen;
m->m_len -= mlen;
eatlen -= mlen;
if (m->m_len == 0)
*mp = m = m_free(m);
}
if (eatlen > 0)
n->m_len -= eatlen;
n->m_next = m;
*mp = m = n;
continue;
}
mlen = min(mlen, len);
if (flags & M_COPYBACK0_COPYBACK) {
memcpy(mtod(m, caddr_t) + off, cp, (unsigned)mlen);
cp += mlen;
}
len -= mlen;
mlen += off;
off = 0;
totlen += mlen;
if (len == 0)
break;
if (m->m_next == 0) {
if ((flags & M_COPYBACK0_EXTEND) == 0)
goto out;
n = m_get(how, m->m_type);
if (n == 0)
break;
n->m_len = min(MLEN, len);
m->m_next = n;
}
mp = &m->m_next;
m = m->m_next;
}
out: if (((m = *mp0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
m->m_pkthdr.len = totlen;
return 0;
enobufs:
return ENOBUFS;
}
/*
* 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 *, caddr_t, unsigned int), void *arg)
{
unsigned int count;
int rval;
KASSERT(len >= 0);
KASSERT(off >= 0);
while (off > 0) {
KASSERT(m != NULL);
if (off < m->m_len)
break;
off -= m->m_len;
m = m->m_next;
}
while (len > 0) {
KASSERT(m != NULL);
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);
} else
return (NULL);
} else
m = m->m_next;
}
}
return (NULL);
}
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