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NetBSD/sys/kern/uipc_mbuf.c

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/* $NetBSD: uipc_mbuf.c,v 1.252 2023/11/27 02:50:27 ozaki-r Exp $ */
/*
* Copyright (c) 1999, 2001, 2018 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, and Maxime Villard.
*
* 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.
*
* 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, "$NetBSD: uipc_mbuf.c,v 1.252 2023/11/27 02:50:27 ozaki-r Exp $");
#ifdef _KERNEL_OPT
#include "opt_mbuftrace.h"
#include "opt_nmbclusters.h"
#include "opt_ddb.h"
#include "ether.h"
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/atomic.h>
#include <sys/cpu.h>
#include <sys/proc.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/percpu.h>
#include <sys/pool.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
pool_cache_t mb_cache; /* mbuf cache */
static pool_cache_t mcl_cache; /* mbuf cluster cache */
struct mbstat mbstat;
int max_linkhdr;
int max_protohdr;
int max_hdr;
int max_datalen;
static void mb_drain(void *, int);
static int mb_ctor(void *, void *, int);
static void sysctl_kern_mbuf_setup(void);
static struct sysctllog *mbuf_sysctllog;
static struct mbuf *m_copy_internal(struct mbuf *, int, int, int, bool);
static struct mbuf *m_split_internal(struct mbuf *, int, int, bool);
static int m_copyback_internal(struct mbuf **, int, int, const void *,
int, int);
/* Flags for m_copyback_internal. */
#define CB_COPYBACK 0x0001 /* copyback from cp */
#define CB_PRESERVE 0x0002 /* preserve original data */
#define CB_COW 0x0004 /* do copy-on-write */
#define CB_EXTEND 0x0008 /* extend chain */
static const char mclpool_warnmsg[] =
"WARNING: mclpool limit reached; increase kern.mbuf.nmbclusters";
MALLOC_DEFINE(M_MBUF, "mbuf", "mbuf");
static percpu_t *mbstat_percpu;
#ifdef MBUFTRACE
struct mownerhead mowners = LIST_HEAD_INITIALIZER(mowners);
struct mowner unknown_mowners[] = {
MOWNER_INIT("unknown", "free"),
MOWNER_INIT("unknown", "data"),
MOWNER_INIT("unknown", "header"),
MOWNER_INIT("unknown", "soname"),
MOWNER_INIT("unknown", "soopts"),
MOWNER_INIT("unknown", "ftable"),
MOWNER_INIT("unknown", "control"),
MOWNER_INIT("unknown", "oobdata"),
};
struct mowner revoked_mowner = MOWNER_INIT("revoked", "");
#endif
#define MEXT_ISEMBEDDED(m) ((m)->m_ext_ref == (m))
#define MCLADDREFERENCE(o, n) \
do { \
KASSERT(((o)->m_flags & M_EXT) != 0); \
KASSERT(((n)->m_flags & M_EXT) == 0); \
KASSERT((o)->m_ext.ext_refcnt >= 1); \
(n)->m_flags |= ((o)->m_flags & M_EXTCOPYFLAGS); \
atomic_inc_uint(&(o)->m_ext.ext_refcnt); \
(n)->m_ext_ref = (o)->m_ext_ref; \
mowner_ref((n), (n)->m_flags); \
} while (/* CONSTCOND */ 0)
static int
nmbclusters_limit(void)
{
#if defined(PMAP_MAP_POOLPAGE)
/* direct mapping, doesn't use space in kmem_arena */
vsize_t max_size = physmem / 4;
#else
vsize_t max_size = MIN(physmem / 4, nkmempages / 4);
#endif
max_size = max_size * PAGE_SIZE / MCLBYTES;
#ifdef NMBCLUSTERS_MAX
max_size = MIN(max_size, NMBCLUSTERS_MAX);
#endif
return max_size;
}
/*
* Initialize the mbuf allocator.
*/
void
mbinit(void)
{
CTASSERT(sizeof(struct _m_ext) <= MHLEN);
CTASSERT(sizeof(struct mbuf) == MSIZE);
sysctl_kern_mbuf_setup();
mb_cache = pool_cache_init(msize, 0, 0, 0, "mbpl",
NULL, IPL_VM, mb_ctor, NULL, NULL);
KASSERT(mb_cache != NULL);
mcl_cache = pool_cache_init(mclbytes, COHERENCY_UNIT, 0, 0, "mclpl",
NULL, IPL_VM, NULL, NULL, NULL);
KASSERT(mcl_cache != NULL);
pool_cache_set_drain_hook(mb_cache, mb_drain, NULL);
pool_cache_set_drain_hook(mcl_cache, mb_drain, NULL);
/*
* Set an arbitrary default limit on the number of mbuf clusters.
*/
#ifdef NMBCLUSTERS
nmbclusters = MIN(NMBCLUSTERS, nmbclusters_limit());
#else
nmbclusters = MAX(1024,
(vsize_t)physmem * PAGE_SIZE / MCLBYTES / 16);
nmbclusters = MIN(nmbclusters, nmbclusters_limit());
#endif
/*
* 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_cache_sethardlimit(mcl_cache, nmbclusters, mclpool_warnmsg, 60);
mbstat_percpu = percpu_alloc(sizeof(struct mbstat_cpu));
/*
* 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_cache_setlowat(mb_cache, mblowat);
pool_cache_setlowat(mcl_cache, 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
}
static void
mb_drain(void *arg, int flags)
{
struct domain *dp;
const struct protosw *pr;
struct ifnet *ifp;
int s;
KERNEL_LOCK(1, NULL);
s = splvm();
DOMAIN_FOREACH(dp) {
for (pr = dp->dom_protosw;
pr < dp->dom_protoswNPROTOSW; pr++)
if (pr->pr_drain)
(*pr->pr_drain)();
}
/* XXX we cannot use psref in H/W interrupt */
if (!cpu_intr_p()) {
int bound = curlwp_bind();
IFNET_READER_FOREACH(ifp) {
struct psref psref;
if_acquire(ifp, &psref);
if (ifp->if_drain)
(*ifp->if_drain)(ifp);
if_release(ifp, &psref);
}
curlwp_bindx(bound);
}
splx(s);
mbstat.m_drain++;
KERNEL_UNLOCK_ONE(NULL);
}
/*
* sysctl helper routine for the kern.mbuf subtree.
* nmbclusters, 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:
case MBUF_MBLOWAT:
case MBUF_MCLLOWAT:
newval = *(int*)rnode->sysctl_data;
break;
case MBUF_NMBCLUSTERS_LIMIT:
newval = nmbclusters_limit();
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;
if (newval > nmbclusters_limit())
return EINVAL;
nmbclusters = newval;
pool_cache_sethardlimit(mcl_cache, nmbclusters,
mclpool_warnmsg, 60);
break;
case MBUF_MBLOWAT:
mblowat = newval;
pool_cache_setlowat(mb_cache, mblowat);
break;
case MBUF_MCLLOWAT:
mcllowat = newval;
pool_cache_setlowat(mcl_cache, mcllowat);
break;
}
return 0;
}
#ifdef MBUFTRACE
static void
mowner_convert_to_user_cb(void *v1, void *v2, struct cpu_info *ci)
{
struct mowner_counter *mc = v1;
struct mowner_user *mo_user = v2;
int i;
for (i = 0; i < MOWNER_COUNTER_NCOUNTERS; i++) {
mo_user->mo_counter[i] += mc->mc_counter[i];
}
}
static void
mowner_convert_to_user(struct mowner *mo, struct mowner_user *mo_user)
{
memset(mo_user, 0, sizeof(*mo_user));
CTASSERT(sizeof(mo_user->mo_name) == sizeof(mo->mo_name));
CTASSERT(sizeof(mo_user->mo_descr) == sizeof(mo->mo_descr));
memcpy(mo_user->mo_name, mo->mo_name, sizeof(mo->mo_name));
memcpy(mo_user->mo_descr, mo->mo_descr, sizeof(mo->mo_descr));
percpu_foreach(mo->mo_counters, mowner_convert_to_user_cb, mo_user);
}
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) {
struct mowner_user mo_user;
mowner_convert_to_user(mo, &mo_user);
if (oldp != NULL) {
if (*oldlenp - len < sizeof(mo_user)) {
error = ENOMEM;
break;
}
error = copyout(&mo_user, (char *)oldp + len,
sizeof(mo_user));
if (error)
break;
}
len += sizeof(mo_user);
}
if (error == 0)
*oldlenp = len;
return error;
}
#endif /* MBUFTRACE */
void
mbstat_type_add(int type, int diff)
{
struct mbstat_cpu *mb;
int s;
s = splvm();
mb = percpu_getref(mbstat_percpu);
mb->m_mtypes[type] += diff;
percpu_putref(mbstat_percpu);
splx(s);
}
static void
mbstat_convert_to_user_cb(void *v1, void *v2, struct cpu_info *ci)
{
struct mbstat_cpu *mbsc = v1;
struct mbstat *mbs = v2;
int i;
for (i = 0; i < __arraycount(mbs->m_mtypes); i++) {
mbs->m_mtypes[i] += mbsc->m_mtypes[i];
}
}
static void
mbstat_convert_to_user(struct mbstat *mbs)
{
memset(mbs, 0, sizeof(*mbs));
mbs->m_drain = mbstat.m_drain;
percpu_foreach(mbstat_percpu, mbstat_convert_to_user_cb, mbs);
}
static int
sysctl_kern_mbuf_stats(SYSCTLFN_ARGS)
{
struct sysctlnode node;
struct mbstat mbs;
mbstat_convert_to_user(&mbs);
node = *rnode;
node.sysctl_data = &mbs;
node.sysctl_size = sizeof(mbs);
return sysctl_lookup(SYSCTLFN_CALL(&node));
}
static void
sysctl_kern_mbuf_setup(void)
{
KASSERT(mbuf_sysctllog == NULL);
sysctl_createv(&mbuf_sysctllog, 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(&mbuf_sysctllog, 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(&mbuf_sysctllog, 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(&mbuf_sysctllog, 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(&mbuf_sysctllog, 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(&mbuf_sysctllog, 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(&mbuf_sysctllog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_STRUCT, "stats",
SYSCTL_DESCR("mbuf allocation statistics"),
sysctl_kern_mbuf_stats, 0, NULL, 0,
CTL_KERN, KERN_MBUF, MBUF_STATS, CTL_EOL);
#ifdef MBUFTRACE
sysctl_createv(&mbuf_sysctllog, 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
sysctl_createv(&mbuf_sysctllog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READONLY,
CTLTYPE_INT, "nmbclusters_limit",
SYSCTL_DESCR("Limit of nmbclusters"),
sysctl_kern_mbuf, 0, NULL, 0,
CTL_KERN, KERN_MBUF, MBUF_NMBCLUSTERS_LIMIT, CTL_EOL);
}
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;
}
/*
* Add mbuf to the end of a chain
*/
struct mbuf *
m_add(struct mbuf *c, struct mbuf *m)
{
struct mbuf *n;
if (c == NULL)
return m;
for (n = c; n->m_next != NULL; n = n->m_next)
continue;
n->m_next = m;
return c;
}
struct mbuf *
m_get(int how, int type)
{
struct mbuf *m;
KASSERT(type != MT_FREE);
m = pool_cache_get(mb_cache,
how == M_WAIT ? PR_WAITOK|PR_LIMITFAIL : PR_NOWAIT);
if (m == NULL)
return NULL;
KASSERTMSG(((vaddr_t)m->m_dat & PAGE_MASK) + MLEN <= PAGE_SIZE,
"m=%p m->m_dat=%p"
" MLEN=%u PAGE_MASK=0x%x PAGE_SIZE=%u",
m, m->m_dat,
(unsigned)MLEN, (unsigned)PAGE_MASK, (unsigned)PAGE_SIZE);
mbstat_type_add(type, 1);
mowner_init(m, type);
m->m_ext_ref = m; /* default */
m->m_type = type;
m->m_len = 0;
m->m_next = NULL;
m->m_nextpkt = NULL; /* default */
m->m_data = m->m_dat;
m->m_flags = 0; /* default */
return m;
}
struct mbuf *
m_gethdr(int how, int type)
{
struct mbuf *m;
m = m_get(how, type);
if (m == NULL)
return NULL;
m->m_data = m->m_pktdat;
m->m_flags = M_PKTHDR;
m_reset_rcvif(m);
m->m_pkthdr.len = 0;
m->m_pkthdr.csum_flags = 0;
m->m_pkthdr.csum_data = 0;
m->m_pkthdr.segsz = 0;
m->m_pkthdr.ether_vtag = 0;
m->m_pkthdr.pkthdr_flags = 0;
SLIST_INIT(&m->m_pkthdr.tags);
m->m_pkthdr.pattr_class = NULL;
m->m_pkthdr.pattr_af = AF_UNSPEC;
m->m_pkthdr.pattr_hdr = NULL;
return m;
}
struct mbuf *
m_get_n(int how, int type, size_t alignbytes, size_t nbytes)
{
struct mbuf *m;
if (alignbytes > MCLBYTES || nbytes > MCLBYTES - alignbytes)
return NULL;
if ((m = m_get(how, type)) == NULL)
return NULL;
if (nbytes + alignbytes > MLEN) {
m_clget(m, how);
if ((m->m_flags & M_EXT) == 0) {
m_free(m);
return NULL;
}
}
m->m_len = alignbytes + nbytes;
m_adj(m, alignbytes);
return m;
}
struct mbuf *
m_gethdr_n(int how, int type, size_t alignbytes, size_t nbytes)
{
struct mbuf *m;
if (nbytes > MCLBYTES || nbytes > MCLBYTES - alignbytes)
return NULL;
if ((m = m_gethdr(how, type)) == NULL)
return NULL;
if (alignbytes + nbytes > MHLEN) {
m_clget(m, how);
if ((m->m_flags & M_EXT) == 0) {
m_free(m);
return NULL;
}
}
m->m_len = m->m_pkthdr.len = alignbytes + nbytes;
m_adj(m, alignbytes);
return m;
}
void
m_clget(struct mbuf *m, int how)
{
m->m_ext_storage.ext_buf = (char *)pool_cache_get_paddr(mcl_cache,
how == M_WAIT ? (PR_WAITOK|PR_LIMITFAIL) : PR_NOWAIT,
&m->m_ext_storage.ext_paddr);
if (m->m_ext_storage.ext_buf == NULL)
return;
KASSERTMSG((((vaddr_t)m->m_ext_storage.ext_buf & PAGE_MASK) + mclbytes
<= PAGE_SIZE),
"m=%p m->m_ext_storage.ext_buf=%p"
" mclbytes=%u PAGE_MASK=0x%x PAGE_SIZE=%u",
m, m->m_dat,
(unsigned)mclbytes, (unsigned)PAGE_MASK, (unsigned)PAGE_SIZE);
MCLINITREFERENCE(m);
m->m_data = m->m_ext.ext_buf;
m->m_flags = (m->m_flags & ~M_EXTCOPYFLAGS) |
M_EXT|M_EXT_CLUSTER|M_EXT_RW;
m->m_ext.ext_size = MCLBYTES;
m->m_ext.ext_free = NULL;
m->m_ext.ext_arg = NULL;
/* ext_paddr initialized above */
mowner_ref(m, M_EXT|M_EXT_CLUSTER);
}
struct mbuf *
m_getcl(int how, int type, int flags)
{
struct mbuf *mp;
if ((flags & M_PKTHDR) != 0)
mp = m_gethdr(how, type);
else
mp = m_get(how, type);
if (mp == NULL)
return NULL;
MCLGET(mp, how);
if ((mp->m_flags & M_EXT) != 0)
return mp;
m_free(mp);
return NULL;
}
/*
* Utility function for M_PREPEND. Do *NOT* use it directly.
*/
struct mbuf *
m_prepend(struct mbuf *m, int len, int how)
{
struct mbuf *mn;
if (__predict_false(len > MHLEN)) {
panic("%s: len > MHLEN", __func__);
}
KASSERT(len != M_COPYALL);
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);
} else {
MCLAIM(mn, m->m_owner);
}
mn->m_next = m;
m = mn;
if (m->m_flags & M_PKTHDR) {
if (len < MHLEN)
m_align(m, len);
} else {
if (len < MLEN)
m_align(m, len);
}
m->m_len = len;
return m;
}
struct mbuf *
m_copym(struct mbuf *m, int off, int len, int wait)
{
/* Shallow copy on M_EXT. */
return m_copy_internal(m, off, len, wait, false);
}
struct mbuf *
m_dup(struct mbuf *m, int off, int len, int wait)
{
/* Deep copy. */
return m_copy_internal(m, off, len, wait, true);
}
static inline int
m_copylen(int len, int copylen)
{
return (len == M_COPYALL) ? copylen : uimin(len, copylen);
}
static struct mbuf *
m_copy_internal(struct mbuf *m, int off0, int len, int wait, bool deep)
{
struct mbuf *m0 __diagused = m;
int len0 __diagused = len;
struct mbuf *n, **np;
int off = off0;
struct mbuf *top;
int copyhdr = 0;
if (off < 0 || (len != M_COPYALL && len < 0))
panic("%s: off %d, len %d", __func__, off, len);
if (off == 0 && m->m_flags & M_PKTHDR)
copyhdr = 1;
while (off > 0) {
if (m == NULL)
panic("%s: m == NULL, off %d", __func__, off);
if (off < m->m_len)
break;
off -= m->m_len;
m = m->m_next;
}
np = &top;
top = NULL;
while (len == M_COPYALL || len > 0) {
if (m == NULL) {
if (len != M_COPYALL)
panic("%s: m == NULL, len %d [!COPYALL]",
__func__, len);
break;
}
n = m_get(wait, m->m_type);
*np = n;
if (n == NULL)
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 = m_copylen(len, m->m_len - off);
if (m->m_flags & M_EXT) {
if (!deep) {
n->m_data = m->m_data + off;
MCLADDREFERENCE(m, n);
} else {
/*
* We don't care if MCLGET fails. n->m_len is
* recomputed and handles that.
*/
MCLGET(n, wait);
n->m_len = 0;
n->m_len = M_TRAILINGSPACE(n);
n->m_len = m_copylen(len, n->m_len);
n->m_len = uimin(n->m_len, m->m_len - off);
memcpy(mtod(n, void *), mtod(m, char *) + off,
(unsigned)n->m_len);
}
} else {
memcpy(mtod(n, void *), mtod(m, char *) + off,
(unsigned)n->m_len);
}
if (len != M_COPYALL)
len -= n->m_len;
off += n->m_len;
KASSERTMSG(off <= m->m_len,
"m=%p m->m_len=%d off=%d len=%d m0=%p off0=%d len0=%d",
m, m->m_len, off, len, m0, off0, len0);
if (off == m->m_len) {
m = m->m_next;
off = 0;
}
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)'.
*/
struct mbuf *
m_copypacket(struct mbuf *m, int how)
{
struct mbuf *top, *n, *o;
if (__predict_false((m->m_flags & M_PKTHDR) == 0)) {
panic("%s: no header (m = %p)", __func__, m);
}
n = m_get(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;
MCLADDREFERENCE(m, n);
} else {
memcpy(mtod(n, char *), mtod(m, char *), n->m_len);
}
m = m->m_next;
while (m) {
o = m_get(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;
MCLADDREFERENCE(m, n);
} else {
memcpy(mtod(n, char *), mtod(m, char *), n->m_len);
}
m = m->m_next;
}
return top;
nospace:
m_freem(top);
return NULL;
}
void
m_copydata(struct mbuf *m, int off, int len, void *cp)
{
unsigned int count;
struct mbuf *m0 = m;
int len0 = len;
int off0 = off;
void *cp0 = cp;
KASSERT(len != M_COPYALL);
if (off < 0 || len < 0)
panic("m_copydata: off %d, len %d", off, len);
while (off > 0) {
if (m == NULL)
panic("m_copydata(%p,%d,%d,%p): m=NULL, off=%d (%d)",
m0, len0, off0, cp0, off, off0 - off);
if (off < m->m_len)
break;
off -= m->m_len;
m = m->m_next;
}
while (len > 0) {
if (m == NULL)
panic("m_copydata(%p,%d,%d,%p): "
"m=NULL, off=%d (%d), len=%d (%d)",
m0, len0, off0, cp0,
off, off0 - off, len, len0 - len);
count = uimin(m->m_len - off, len);
memcpy(cp, mtod(m, char *) + off, count);
len -= count;
cp = (char *)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, char *) + m->m_len, mtod(n, void *),
(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;
}
}
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 == NULL)
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;
}
if (m) {
while (m->m_next)
(m = m->m_next)->m_len = 0;
}
}
}
/*
* m_ensure_contig: rearrange an mbuf chain that given length of bytes
* would be contiguous and in the data area of an mbuf (therefore, mtod()
* would work for a structure of given length).
*
* => On success, returns true and the resulting mbuf chain; false otherwise.
* => The mbuf chain may change, but is always preserved valid.
*/
bool
m_ensure_contig(struct mbuf **m0, int len)
{
struct mbuf *n = *m0, *m;
size_t count, space;
KASSERT(len != M_COPYALL);
/*
* 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 true;
}
m = n;
n = n->m_next;
len -= m->m_len;
} else {
if (len > MHLEN) {
return false;
}
m = m_get(M_DONTWAIT, n->m_type);
if (m == NULL) {
return false;
}
MCLAIM(m, n->m_owner);
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);
memcpy(mtod(m, char *) + m->m_len, mtod(n, void *),
(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);
m->m_next = n;
*m0 = m;
return len <= 0;
}
/*
* m_pullup: same as m_ensure_contig(), but destroys mbuf chain on error.
*/
struct mbuf *
m_pullup(struct mbuf *n, int len)
{
struct mbuf *m = n;
KASSERT(len != M_COPYALL);
if (!m_ensure_contig(&m, len)) {
KASSERT(m != NULL);
m_freem(m);
m = NULL;
}
return m;
}
/*
* ensure that [off, off + len) is contiguous on the mbuf chain "m".
* packet chain before "off" is kept untouched.
* if offp == NULL, the target will start at <retval, 0> on resulting chain.
* if offp != NULL, the target will start at <retval, *offp> on resulting chain.
*
* on error return (NULL return value), original "m" will be freed.
*
* XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster)
*/
struct mbuf *
m_pulldown(struct mbuf *m, int off, int len, int *offp)
{
struct mbuf *n, *o;
int hlen, tlen, olen;
int sharedcluster;
/* Check invalid arguments. */
if (m == NULL)
panic("%s: m == NULL", __func__);
if (len > MCLBYTES) {
m_freem(m);
return NULL;
}
n = m;
while (n != NULL && off > 0) {
if (n->m_len > off)
break;
off -= n->m_len;
n = n->m_next;
}
/* Be sure to point non-empty mbuf. */
while (n != NULL && n->m_len == 0)
n = n->m_next;
if (!n) {
m_freem(m);
return NULL; /* mbuf chain too short */
}
sharedcluster = M_READONLY(n);
/*
* The target data is on <n, off>. If we got enough data on the mbuf
* "n", we're done.
*/
#ifdef __NO_STRICT_ALIGNMENT
if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster)
#else
if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster &&
ALIGNED_POINTER((mtod(n, char *) + off), uint32_t))
#endif
goto ok;
/*
* When (len <= n->m_len - off) and (off != 0), it is a special case.
* Len bytes from <n, off> sit in single mbuf, but the caller does
* not like the starting position (off).
*
* Chop the current mbuf into two pieces, set off to 0.
*/
if (len <= n->m_len - off) {
struct mbuf *mlast;
o = m_dup(n, off, n->m_len - off, M_DONTWAIT);
if (o == NULL) {
m_freem(m);
return NULL; /* ENOBUFS */
}
KASSERTMSG(o->m_len >= len, "o=%p o->m_len=%d len=%d",
o, o->m_len, len);
for (mlast = o; mlast->m_next != NULL; mlast = mlast->m_next)
;
n->m_len = off;
mlast->m_next = n->m_next;
n->m_next = o;
n = o;
off = 0;
goto ok;
}
/*
* We need to take hlen from <n, off> and tlen from <n->m_next, 0>,
* and construct contiguous mbuf with m_len == len.
*
* Note that hlen + tlen == len, and tlen > 0.
*/
hlen = n->m_len - off;
tlen = len - hlen;
/*
* Ensure that we have enough trailing data on mbuf chain. If not,
* we can do nothing about the chain.
*/
olen = 0;
for (o = n->m_next; o != NULL; o = o->m_next)
olen += o->m_len;
if (hlen + olen < len) {
m_freem(m);
return NULL; /* mbuf chain too short */
}
/*
* Easy cases first. We need to use m_copydata() to get data from
* <n->m_next, 0>.
*/
if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen &&
!sharedcluster) {
m_copydata(n->m_next, 0, tlen, mtod(n, char *) + n->m_len);
n->m_len += tlen;
m_adj(n->m_next, tlen);
goto ok;
}
if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen &&
#ifndef __NO_STRICT_ALIGNMENT
ALIGNED_POINTER((n->m_next->m_data - hlen), uint32_t) &&
#endif
!sharedcluster && n->m_next->m_len >= tlen) {
n->m_next->m_data -= hlen;
n->m_next->m_len += hlen;
memcpy(mtod(n->m_next, void *), mtod(n, char *) + off, hlen);
n->m_len -= hlen;
n = n->m_next;
off = 0;
goto ok;
}
/*
* Now, we need to do the hard way. Don't copy as there's no room
* on both ends.
*/
o = m_get(M_DONTWAIT, m->m_type);
if (o && len > MLEN) {
MCLGET(o, M_DONTWAIT);
if ((o->m_flags & M_EXT) == 0) {
m_free(o);
o = NULL;
}
}
if (!o) {
m_freem(m);
return NULL; /* ENOBUFS */
}
/* get hlen from <n, off> into <o, 0> */
o->m_len = hlen;
memcpy(mtod(o, void *), mtod(n, char *) + off, hlen);
n->m_len -= hlen;
/* get tlen from <n->m_next, 0> into <o, hlen> */
m_copydata(n->m_next, 0, tlen, mtod(o, char *) + o->m_len);
o->m_len += tlen;
m_adj(n->m_next, tlen);
o->m_next = n->m_next;
n->m_next = o;
n = o;
off = 0;
ok:
if (offp)
*offp = off;
return n;
}
/*
* 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;
KASSERT(len != M_COPYALL);
if (len > ((int)MHLEN - dstoff))
goto bad;
m = m_get(M_DONTWAIT, n->m_type);
if (m == NULL)
goto bad;
MCLAIM(m, n->m_owner);
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 = uimin(uimin(uimax(len, max_protohdr), space), n->m_len);
memcpy(mtod(m, char *) + m->m_len, mtod(n, void *),
(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;
}
struct mbuf *
m_split(struct mbuf *m0, int len, int wait)
{
return m_split_internal(m0, len, wait, true);
}
static struct mbuf *
m_split_internal(struct mbuf *m0, int len0, int wait, bool copyhdr)
{
struct mbuf *m, *n;
unsigned len = len0, remain, len_save;
KASSERT(len0 != M_COPYALL);
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 (copyhdr && (m0->m_flags & M_PKTHDR)) {
n = m_gethdr(wait, m0->m_type);
if (n == NULL)
return NULL;
MCLAIM(n, m0->m_owner);
m_copy_rcvif(n, m0);
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) == 0 && remain > MHLEN) {
/* m can't be the lead packet */
m_align(n, 0);
n->m_len = 0;
n->m_next = m_split(m, len, wait);
if (n->m_next == NULL) {
(void)m_free(n);
m0->m_pkthdr.len = len_save;
return NULL;
}
return n;
}
} 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;
MCLAIM(n, m->m_owner);
}
if (m->m_flags & M_EXT) {
n->m_data = m->m_data + len;
MCLADDREFERENCE(m, n);
} else {
m_align(n, remain);
memcpy(mtod(n, void *), mtod(m, char *) + len, 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 off, struct ifnet *ifp)
{
struct mbuf *m;
struct mbuf *top = NULL, **mp = &top;
char *cp, *epkt;
int len;
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(uint16_t);
totlen -= 2 * sizeof(uint16_t);
}
m = m_gethdr(M_DONTWAIT, MT_DATA);
if (m == NULL)
return NULL;
m_set_rcvif(m, ifp);
m->m_pkthdr.len = totlen;
m->m_len = MHLEN;
while (totlen > 0) {
if (top) {
m = m_get(M_DONTWAIT, MT_DATA);
if (m == NULL) {
m_freem(top);
return NULL;
}
m->m_len = MLEN;
}
len = uimin(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 = uimin(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;
}
memcpy(mtod(m, void *), 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
if (m0 == NULL)
return;
#if defined(DEBUG)
error =
#endif
m_copyback_internal(&m0, off, len, cp, CB_COPYBACK|CB_EXTEND,
M_DONTWAIT);
#if defined(DEBUG)
if (error != 0 || (m0 != NULL && origm != m0))
panic("m_copyback");
#endif
}
struct mbuf *
m_copyback_cow(struct mbuf *m0, int off, int len, const void *cp, int how)
{
int error;
/* don't support chain expansion */
KASSERT(len != M_COPYALL);
KDASSERT(off + len <= m_length(m0));
error = m_copyback_internal(&m0, off, len, cp, CB_COPYBACK|CB_COW,
how);
if (error) {
/*
* no way to recover from partial success.
* just free the chain.
*/
m_freem(m0);
return NULL;
}
return m0;
}
int
m_makewritable(struct mbuf **mp, int off, int len, int how)
{
int error;
#if defined(DEBUG)
int origlen = m_length(*mp);
#endif
error = m_copyback_internal(mp, off, len, NULL, CB_PRESERVE|CB_COW,
how);
if (error)
return error;
#if defined(DEBUG)
int reslen = 0;
for (struct mbuf *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
return 0;
}
static int
m_copyback_internal(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 & CB_PRESERVE) == 0 || cp == NULL);
KASSERT((flags & CB_COPYBACK) == 0 || cp != NULL);
if (len == M_COPYALL)
len = m_length(*mp0) - off;
/*
* we don't bother to update "totlen" in the case of CB_COW,
* assuming that CB_EXTEND and CB_COW are exclusive.
*/
KASSERT((~flags & (CB_EXTEND|CB_COW)) != 0);
mp = mp0;
m = *mp;
while (off > (mlen = m->m_len)) {
off -= mlen;
totlen += mlen;
if (m->m_next == NULL) {
int tspace;
extend:
if ((flags & CB_EXTEND) == 0)
goto out;
/*
* try to make some space at the end of "m".
*/
mlen = m->m_len;
if (off + len >= MINCLSIZE &&
(m->m_flags & M_EXT) == 0 && m->m_len == 0) {
MCLGET(m, how);
}
tspace = M_TRAILINGSPACE(m);
if (tspace > 0) {
tspace = uimin(tspace, off + len);
KASSERT(tspace > 0);
memset(mtod(m, char *) + m->m_len, 0,
uimin(off, tspace));
m->m_len += tspace;
off += mlen;
totlen -= mlen;
continue;
}
/*
* need to allocate an mbuf.
*/
if (off + len >= MINCLSIZE) {
n = m_getcl(how, m->m_type, 0);
} else {
n = m_get(how, m->m_type);
}
if (n == NULL) {
goto out;
}
n->m_len = uimin(M_TRAILINGSPACE(n), off + len);
memset(mtod(n, char *), 0, uimin(n->m_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)) {
/*
* This mbuf is read-only. Allocate a new writable
* mbuf and try again.
*/
char *datap;
int eatlen;
KASSERT((flags & CB_COW) != 0);
/*
* if we're going to write into the middle of
* a mbuf, split it first.
*/
if (off > 0) {
n = m_split_internal(m, off, how, false);
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.
*/
n = m_get(how, m->m_type);
if (n == NULL)
goto enobufs;
MCLAIM(n, m->m_owner);
if (off == 0 && (m->m_flags & M_PKTHDR) != 0) {
m_move_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 & CB_PRESERVE)
datap = mtod(n, char *);
else
datap = NULL;
eatlen = n->m_len;
while (m != NULL && M_READONLY(m) &&
n->m_type == m->m_type && eatlen > 0) {
mlen = uimin(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 = uimin(mlen, len);
if (flags & CB_COPYBACK) {
memcpy(mtod(m, char *) + off, cp, (unsigned)mlen);
cp += mlen;
}
len -= mlen;
mlen += off;
off = 0;
totlen += mlen;
if (len == 0)
break;
if (m->m_next == NULL) {
goto extend;
}
mp = &m->m_next;
m = m->m_next;
}
out:
if (((m = *mp0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) {
KASSERT((flags & CB_EXTEND) != 0);
m->m_pkthdr.len = totlen;
}
return 0;
enobufs:
return ENOBUFS;
}
/*
* Compress the mbuf chain. Return the new mbuf chain on success, NULL on
* failure. The first mbuf is preserved, and on success the pointer returned
* is the same as the one passed.
*/
struct mbuf *
m_defrag(struct mbuf *m, int how)
{
struct mbuf *m0, *mn, *n;
int sz;
KASSERT((m->m_flags & M_PKTHDR) != 0);
if (m->m_next == NULL)
return m;
/* Defrag to single mbuf if at all possible */
if ((m->m_flags & M_EXT) == 0 && m->m_pkthdr.len <= MCLBYTES) {
if (m->m_pkthdr.len <= MHLEN) {
if (M_TRAILINGSPACE(m) < (m->m_pkthdr.len - m->m_len)) {
KASSERTMSG(M_LEADINGSPACE(m) +
M_TRAILINGSPACE(m) >=
(m->m_pkthdr.len - m->m_len),
"too small leading %d trailing %d ro? %d"
" pkthdr.len %d mlen %d",
(int)M_LEADINGSPACE(m),
(int)M_TRAILINGSPACE(m),
M_READONLY(m),
m->m_pkthdr.len, m->m_len);
memmove(m->m_pktdat, m->m_data, m->m_len);
m->m_data = m->m_pktdat;
KASSERT(M_TRAILINGSPACE(m) >=
(m->m_pkthdr.len - m->m_len));
}
} else {
/* Must copy data before adding cluster */
m0 = m_get(how, MT_DATA);
if (m0 == NULL)
return NULL;
KASSERTMSG(m->m_len <= MHLEN,
"m=%p m->m_len=%d MHLEN=%u",
m, m->m_len, (unsigned)MHLEN);
m_copydata(m, 0, m->m_len, mtod(m0, void *));
MCLGET(m, how);
if ((m->m_flags & M_EXT) == 0) {
m_free(m0);
return NULL;
}
memcpy(m->m_data, mtod(m0, void *), m->m_len);
m_free(m0);
}
KASSERTMSG(M_TRAILINGSPACE(m) >= (m->m_pkthdr.len - m->m_len),
"m=%p M_TRAILINGSPACE(m)=%zd m->m_pkthdr.len=%d"
" m->m_len=%d",
m, M_TRAILINGSPACE(m), m->m_pkthdr.len, m->m_len);
m_copydata(m->m_next, 0, m->m_pkthdr.len - m->m_len,
mtod(m, char *) + m->m_len);
m->m_len = m->m_pkthdr.len;
m_freem(m->m_next);
m->m_next = NULL;
return m;
}
m0 = m_get(how, MT_DATA);
if (m0 == NULL)
return NULL;
mn = m0;
sz = m->m_pkthdr.len - m->m_len;
KASSERT(sz >= 0);
do {
if (sz > MLEN) {
MCLGET(mn, how);
if ((mn->m_flags & M_EXT) == 0) {
m_freem(m0);
return NULL;
}
}
mn->m_len = MIN(sz, MCLBYTES);
m_copydata(m, m->m_pkthdr.len - sz, mn->m_len,
mtod(mn, void *));
sz -= mn->m_len;
if (sz > 0) {
/* need more mbufs */
n = m_get(how, MT_DATA);
if (n == NULL) {
m_freem(m0);
return NULL;
}
mn->m_next = n;
mn = n;
}
} while (sz > 0);
m_freem(m->m_next);
m->m_next = m0;
return m;
}
void
m_remove_pkthdr(struct mbuf *m)
{
KASSERT(m->m_flags & M_PKTHDR);
m_tag_delete_chain(m);
m->m_flags &= ~M_PKTHDR;
memset(&m->m_pkthdr, 0, sizeof(m->m_pkthdr));
}
void
m_copy_pkthdr(struct mbuf *to, struct mbuf *from)
{
KASSERT((to->m_flags & M_EXT) == 0);
KASSERT((to->m_flags & M_PKTHDR) == 0 ||
SLIST_FIRST(&to->m_pkthdr.tags) == NULL);
KASSERT((from->m_flags & M_PKTHDR) != 0);
to->m_pkthdr = from->m_pkthdr;
to->m_flags = from->m_flags & M_COPYFLAGS;
to->m_data = to->m_pktdat;
SLIST_INIT(&to->m_pkthdr.tags);
m_tag_copy_chain(to, from);
}
void
m_move_pkthdr(struct mbuf *to, struct mbuf *from)
{
KASSERT((to->m_flags & M_EXT) == 0);
KASSERT((to->m_flags & M_PKTHDR) == 0 ||
SLIST_FIRST(&to->m_pkthdr.tags) == NULL);
KASSERT((from->m_flags & M_PKTHDR) != 0);
to->m_pkthdr = from->m_pkthdr;
to->m_flags = from->m_flags & M_COPYFLAGS;
to->m_data = to->m_pktdat;
from->m_flags &= ~M_PKTHDR;
}
/*
* Set the m_data pointer of a newly-allocated mbuf to place an object of the
* specified size at the end of the mbuf, longword aligned.
*/
void
m_align(struct mbuf *m, int len)
{
int buflen, adjust;
KASSERT(len != M_COPYALL);
KASSERTMSG(M_LEADINGSPACE(m) == 0, "m=%p M_LEADINGSPACE(m)=%zd",
m, M_LEADINGSPACE(m));
buflen = M_BUFSIZE(m);
KASSERTMSG(len <= buflen, "m=%p len=%d buflen=%d", m, len, buflen);
adjust = buflen - len;
m->m_data += adjust &~ (sizeof(long)-1);
}
/*
* 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 *, unsigned int), void *arg)
{
unsigned int count;
int rval;
KASSERT(len != M_COPYALL);
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 = uimin(m->m_len - off, len);
rval = (*f)(arg, mtod(m, char *) + 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;
}
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;
} else {
m = m->m_next;
}
}
return NULL;
}
/*
* Release a reference to the mbuf external storage.
*
* => free the mbuf m itself as well.
*/
static void
m_ext_free(struct mbuf *m)
{
const bool embedded = MEXT_ISEMBEDDED(m);
bool dofree = true;
u_int refcnt;
KASSERT((m->m_flags & M_EXT) != 0);
KASSERT(MEXT_ISEMBEDDED(m->m_ext_ref));
KASSERT((m->m_ext_ref->m_flags & M_EXT) != 0);
KASSERT((m->m_flags & M_EXT_CLUSTER) ==
(m->m_ext_ref->m_flags & M_EXT_CLUSTER));
if (__predict_false(m->m_type == MT_FREE)) {
panic("mbuf %p already freed", m);
}
if (__predict_true(m->m_ext.ext_refcnt == 1)) {
refcnt = m->m_ext.ext_refcnt = 0;
} else {
membar_release();
refcnt = atomic_dec_uint_nv(&m->m_ext.ext_refcnt);
}
if (refcnt > 0) {
if (embedded) {
/*
* other mbuf's m_ext_ref still points to us.
*/
dofree = false;
} else {
m->m_ext_ref = m;
}
} else {
/*
* dropping the last reference
*/
membar_acquire();
if (!embedded) {
m->m_ext.ext_refcnt++; /* XXX */
m_ext_free(m->m_ext_ref);
m->m_ext_ref = m;
} else if ((m->m_flags & M_EXT_CLUSTER) != 0) {
pool_cache_put_paddr(mcl_cache,
m->m_ext.ext_buf, m->m_ext.ext_paddr);
} else if (m->m_ext.ext_free) {
(*m->m_ext.ext_free)(m,
m->m_ext.ext_buf, m->m_ext.ext_size,
m->m_ext.ext_arg);
/*
* 'm' is already freed by the ext_free callback.
*/
dofree = false;
} else {
free(m->m_ext.ext_buf, 0);
}
}
if (dofree) {
m->m_type = MT_FREE;
m->m_data = NULL;
pool_cache_put(mb_cache, m);
}
}
/*
* Free a single mbuf and associated external storage. Return the
* successor, if any.
*/
struct mbuf *
m_free(struct mbuf *m)
{
struct mbuf *n;
mowner_revoke(m, 1, m->m_flags);
mbstat_type_add(m->m_type, -1);
if (m->m_flags & M_PKTHDR)
m_tag_delete_chain(m);
n = m->m_next;
if (m->m_flags & M_EXT) {
m_ext_free(m);
} else {
if (__predict_false(m->m_type == MT_FREE)) {
panic("mbuf %p already freed", m);
}
m->m_type = MT_FREE;
m->m_data = NULL;
pool_cache_put(mb_cache, m);
}
return n;
}
void
m_freem(struct mbuf *m)
{
if (m == NULL)
return;
do {
m = m_free(m);
} while (m);
}
#if defined(DDB)
void
m_print(const struct mbuf *m, const char *modif, void (*pr)(const char *, ...))
{
char ch;
bool opt_c = false;
bool opt_d = false;
#if NETHER > 0
bool opt_v = false;
const struct mbuf *m0 = NULL;
#endif
int no = 0;
char buf[512];
while ((ch = *(modif++)) != '\0') {
switch (ch) {
case 'c':
opt_c = true;
break;
case 'd':
opt_d = true;
break;
#if NETHER > 0
case 'v':
opt_v = true;
m0 = m;
break;
#endif
default:
break;
}
}
nextchain:
(*pr)("MBUF(%d) %p\n", no, m);
snprintb(buf, sizeof(buf), M_FLAGS_BITS, (u_int)m->m_flags);
(*pr)(" data=%p, len=%d, type=%d, flags=%s\n",
m->m_data, m->m_len, m->m_type, buf);
if (opt_d) {
int i;
unsigned char *p = m->m_data;
(*pr)(" data:");
for (i = 0; i < m->m_len; i++) {
if (i % 16 == 0)
(*pr)("\n");
(*pr)(" %02x", p[i]);
}
(*pr)("\n");
}
(*pr)(" owner=%p, next=%p, nextpkt=%p\n", m->m_owner, m->m_next,
m->m_nextpkt);
(*pr)(" leadingspace=%u, trailingspace=%u, readonly=%u\n",
(int)M_LEADINGSPACE(m), (int)M_TRAILINGSPACE(m),
(int)M_READONLY(m));
if ((m->m_flags & M_PKTHDR) != 0) {
snprintb(buf, sizeof(buf), M_CSUM_BITS, m->m_pkthdr.csum_flags);
(*pr)(" pktlen=%d, rcvif=%p, csum_flags=%s, csum_data=0x%"
PRIx32 ", segsz=%u\n",
m->m_pkthdr.len, m_get_rcvif_NOMPSAFE(m),
buf, m->m_pkthdr.csum_data, m->m_pkthdr.segsz);
}
if ((m->m_flags & M_EXT)) {
(*pr)(" ext_refcnt=%u, ext_buf=%p, ext_size=%zd, "
"ext_free=%p, ext_arg=%p\n",
m->m_ext.ext_refcnt,
m->m_ext.ext_buf, m->m_ext.ext_size,
m->m_ext.ext_free, m->m_ext.ext_arg);
}
if ((~m->m_flags & (M_EXT|M_EXT_PAGES)) == 0) {
vaddr_t sva = (vaddr_t)m->m_ext.ext_buf;
vaddr_t eva = sva + m->m_ext.ext_size;
int n = (round_page(eva) - trunc_page(sva)) >> PAGE_SHIFT;
int i;
(*pr)(" pages:");
for (i = 0; i < n; i ++) {
(*pr)(" %p", m->m_ext.ext_pgs[i]);
}
(*pr)("\n");
}
if (opt_c) {
m = m->m_next;
if (m != NULL) {
no++;
goto nextchain;
}
}
#if NETHER > 0
if (opt_v && m0)
m_examine(m0, AF_ETHER, modif, pr);
#endif
}
#endif /* defined(DDB) */
#if defined(MBUFTRACE)
void
mowner_init_owner(struct mowner *mo, const char *name, const char *descr)
{
memset(mo, 0, sizeof(*mo));
strlcpy(mo->mo_name, name, sizeof(mo->mo_name));
strlcpy(mo->mo_descr, descr, sizeof(mo->mo_descr));
}
void
mowner_attach(struct mowner *mo)
{
KASSERT(mo->mo_counters == NULL);
mo->mo_counters = percpu_alloc(sizeof(struct mowner_counter));
/* XXX lock */
LIST_INSERT_HEAD(&mowners, mo, mo_link);
}
void
mowner_detach(struct mowner *mo)
{
KASSERT(mo->mo_counters != NULL);
/* XXX lock */
LIST_REMOVE(mo, mo_link);
percpu_free(mo->mo_counters, sizeof(struct mowner_counter));
mo->mo_counters = NULL;
}
void
mowner_init(struct mbuf *m, int type)
{
struct mowner_counter *mc;
struct mowner *mo;
int s;
m->m_owner = mo = &unknown_mowners[type];
s = splvm();
mc = percpu_getref(mo->mo_counters);
mc->mc_counter[MOWNER_COUNTER_CLAIMS]++;
percpu_putref(mo->mo_counters);
splx(s);
}
void
mowner_ref(struct mbuf *m, int flags)
{
struct mowner *mo = m->m_owner;
struct mowner_counter *mc;
int s;
s = splvm();
mc = percpu_getref(mo->mo_counters);
if ((flags & M_EXT) != 0)
mc->mc_counter[MOWNER_COUNTER_EXT_CLAIMS]++;
if ((flags & M_EXT_CLUSTER) != 0)
mc->mc_counter[MOWNER_COUNTER_CLUSTER_CLAIMS]++;
percpu_putref(mo->mo_counters);
splx(s);
}
void
mowner_revoke(struct mbuf *m, bool all, int flags)
{
struct mowner *mo = m->m_owner;
struct mowner_counter *mc;
int s;
s = splvm();
mc = percpu_getref(mo->mo_counters);
if ((flags & M_EXT) != 0)
mc->mc_counter[MOWNER_COUNTER_EXT_RELEASES]++;
if ((flags & M_EXT_CLUSTER) != 0)
mc->mc_counter[MOWNER_COUNTER_CLUSTER_RELEASES]++;
if (all)
mc->mc_counter[MOWNER_COUNTER_RELEASES]++;
percpu_putref(mo->mo_counters);
splx(s);
if (all)
m->m_owner = &revoked_mowner;
}
static void
mowner_claim(struct mbuf *m, struct mowner *mo)
{
struct mowner_counter *mc;
int flags = m->m_flags;
int s;
s = splvm();
mc = percpu_getref(mo->mo_counters);
mc->mc_counter[MOWNER_COUNTER_CLAIMS]++;
if ((flags & M_EXT) != 0)
mc->mc_counter[MOWNER_COUNTER_EXT_CLAIMS]++;
if ((flags & M_EXT_CLUSTER) != 0)
mc->mc_counter[MOWNER_COUNTER_CLUSTER_CLAIMS]++;
percpu_putref(mo->mo_counters);
splx(s);
m->m_owner = mo;
}
void
m_claim(struct mbuf *m, struct mowner *mo)
{
if (m->m_owner == mo || mo == NULL)
return;
mowner_revoke(m, true, m->m_flags);
mowner_claim(m, mo);
}
void
m_claimm(struct mbuf *m, struct mowner *mo)
{
for (; m != NULL; m = m->m_next)
m_claim(m, mo);
}
#endif /* defined(MBUFTRACE) */
#ifdef DIAGNOSTIC
/*
* Verify that the mbuf chain is not malformed. Used only for diagnostic.
* Panics on error.
*/
void
m_verify_packet(struct mbuf *m)
{
struct mbuf *n = m;
char *low, *high, *dat;
int totlen = 0, len;
if (__predict_false((m->m_flags & M_PKTHDR) == 0)) {
panic("%s: mbuf doesn't have M_PKTHDR", __func__);
}
while (n != NULL) {
if (__predict_false(n->m_type == MT_FREE)) {
panic("%s: mbuf already freed (n = %p)", __func__, n);
}
#if 0
/*
* This ought to be a rule of the mbuf API. Unfortunately,
* many places don't respect that rule.
*/
if (__predict_false((n != m) && (n->m_flags & M_PKTHDR) != 0)) {
panic("%s: M_PKTHDR set on secondary mbuf", __func__);
}
#endif
if (__predict_false(n->m_nextpkt != NULL)) {
panic("%s: m_nextpkt not null (m_nextpkt = %p)",
__func__, n->m_nextpkt);
}
dat = n->m_data;
len = n->m_len;
if (__predict_false(len < 0)) {
panic("%s: incorrect length (len = %d)", __func__, len);
}
low = M_BUFADDR(n);
high = low + M_BUFSIZE(n);
if (__predict_false((dat < low) || (dat + len > high))) {
panic("%s: m_data not in packet"
"(dat = %p, len = %d, low = %p, high = %p)",
__func__, dat, len, low, high);
}
totlen += len;
n = n->m_next;
}
if (__predict_false(totlen != m->m_pkthdr.len)) {
panic("%s: inconsistent mbuf length (%d != %d)", __func__,
totlen, m->m_pkthdr.len);
}
}
#endif
struct m_tag *
m_tag_get(int type, int len, int wait)
{
struct m_tag *t;
if (len < 0)
return NULL;
t = malloc(len + sizeof(struct m_tag), M_PACKET_TAGS, wait);
if (t == NULL)
return NULL;
t->m_tag_id = type;
t->m_tag_len = len;
return t;
}
void
m_tag_free(struct m_tag *t)
{
free(t, M_PACKET_TAGS);
}
void
m_tag_prepend(struct mbuf *m, struct m_tag *t)
{
KASSERT((m->m_flags & M_PKTHDR) != 0);
SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
}
void
m_tag_unlink(struct mbuf *m, struct m_tag *t)
{
KASSERT((m->m_flags & M_PKTHDR) != 0);
SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
}
void
m_tag_delete(struct mbuf *m, struct m_tag *t)
{
m_tag_unlink(m, t);
m_tag_free(t);
}
void
m_tag_delete_chain(struct mbuf *m)
{
struct m_tag *p, *q;
KASSERT((m->m_flags & M_PKTHDR) != 0);
p = SLIST_FIRST(&m->m_pkthdr.tags);
if (p == NULL)
return;
while ((q = SLIST_NEXT(p, m_tag_link)) != NULL)
m_tag_delete(m, q);
m_tag_delete(m, p);
}
struct m_tag *
m_tag_find(const struct mbuf *m, int type)
{
struct m_tag *p;
KASSERT((m->m_flags & M_PKTHDR) != 0);
p = SLIST_FIRST(&m->m_pkthdr.tags);
while (p != NULL) {
if (p->m_tag_id == type)
return p;
p = SLIST_NEXT(p, m_tag_link);
}
return NULL;
}
struct m_tag *
m_tag_copy(struct m_tag *t)
{
struct m_tag *p;
p = m_tag_get(t->m_tag_id, t->m_tag_len, M_NOWAIT);
if (p == NULL)
return NULL;
memcpy(p + 1, t + 1, t->m_tag_len);
return p;
}
/*
* Copy two tag chains. The destination mbuf (to) loses any attached
* tags even if the operation fails. This should not be a problem, as
* m_tag_copy_chain() is typically called with a newly-allocated
* destination mbuf.
*/
int
m_tag_copy_chain(struct mbuf *to, struct mbuf *from)
{
struct m_tag *p, *t, *tprev = NULL;
KASSERT((from->m_flags & M_PKTHDR) != 0);
m_tag_delete_chain(to);
SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) {
t = m_tag_copy(p);
if (t == NULL) {
m_tag_delete_chain(to);
return 0;
}
if (tprev == NULL)
SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link);
else
SLIST_INSERT_AFTER(tprev, t, m_tag_link);
tprev = t;
}
return 1;
}
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