OpenBSD-4.6/sys/kern/uipc_mbuf.c
/* $OpenBSD: uipc_mbuf.c,v 1.122 2009/06/22 10:51:06 thib Exp $ */
/* $NetBSD: uipc_mbuf.c,v 1.15.4.1 1996/06/13 17:11:44 cgd Exp $ */
/*
* Copyright (c) 1982, 1986, 1988, 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94
*/
/*
* @(#)COPYRIGHT 1.1 (NRL) 17 January 1995
*
* NRL grants permission for redistribution and use in source and binary
* forms, with or without modification, of the software and documentation
* created at NRL 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 acknowledgements:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* This product includes software developed at the Information
* Technology Division, US Naval Research Laboratory.
* 4. Neither the name of the NRL nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL 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 NRL 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.
*
* The views and conclusions contained in the software and documentation
* are those of the authors and should not be interpreted as representing
* official policies, either expressed or implied, of the US Naval
* Research Laboratory (NRL).
*/
#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/socketvar.h>
#include <net/if.h>
#include <machine/cpu.h>
#include <uvm/uvm_extern.h>
struct mbstat mbstat; /* mbuf stats */
struct pool mbpool; /* mbuf pool */
/* mbuf cluster pools */
u_int mclsizes[] = {
MCLBYTES, /* must be at slot 0 */
4 * 1024,
8 * 1024,
9 * 1024,
12 * 1024,
16 * 1024,
64 * 1024
};
static char mclnames[MCLPOOLS][8];
struct pool mclpools[MCLPOOLS];
int m_clpool(u_int);
int max_linkhdr; /* largest link-level header */
int max_protohdr; /* largest protocol header */
int max_hdr; /* largest link+protocol header */
int max_datalen; /* MHLEN - max_hdr */
void m_extfree(struct mbuf *);
struct mbuf *m_copym0(struct mbuf *, int, int, int, int);
void nmbclust_update(void);
const char *mclpool_warnmsg =
"WARNING: mclpools limit reached; increase kern.maxclusters";
/*
* Initialize the mbuf allocator.
*/
void
mbinit(void)
{
int i;
pool_init(&mbpool, MSIZE, 0, 0, 0, "mbpl", NULL);
pool_setlowat(&mbpool, mblowat);
for (i = 0; i < nitems(mclsizes); i++) {
snprintf(mclnames[i], sizeof(mclnames[0]), "mcl%dk",
mclsizes[i] >> 10);
pool_init(&mclpools[i], mclsizes[i], 0, 0, 0, mclnames[i],
NULL);
pool_setlowat(&mclpools[i], mcllowat);
}
nmbclust_update();
}
void
nmbclust_update(void)
{
int i;
/*
* Set the hard limit on the mclpools to the number of
* mbuf clusters the kernel is to support. Log the limit
* reached message max once a minute.
*/
for (i = 0; i < nitems(mclsizes); i++) {
(void)pool_sethardlimit(&mclpools[i], nmbclust,
mclpool_warnmsg, 60);
}
pool_sethiwat(&mbpool, nmbclust);
}
void
m_reclaim(void *arg, int flags)
{
struct domain *dp;
struct protosw *pr;
int s = splnet();
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++;
splx(s);
}
/*
* Space allocation routines.
*/
struct mbuf *
m_get(int nowait, int type)
{
struct mbuf *m;
int s;
s = splnet();
m = pool_get(&mbpool, nowait == M_WAIT ? PR_WAITOK : 0);
if (m)
mbstat.m_mtypes[type]++;
splx(s);
if (m) {
m->m_type = type;
m->m_next = (struct mbuf *)NULL;
m->m_nextpkt = (struct mbuf *)NULL;
m->m_data = m->m_dat;
m->m_flags = 0;
}
return (m);
}
/*
* ATTN: When changing anything here check m_inithdr() and m_defrag() those
* may need to change as well.
*/
struct mbuf *
m_gethdr(int nowait, int type)
{
struct mbuf *m;
int s;
s = splnet();
m = pool_get(&mbpool, nowait == M_WAIT ? PR_WAITOK : 0);
if (m)
mbstat.m_mtypes[type]++;
splx(s);
if (m) {
m->m_type = type;
/* keep in sync with m_inithdr */
m->m_next = (struct mbuf *)NULL;
m->m_nextpkt = (struct mbuf *)NULL;
m->m_data = m->m_pktdat;
m->m_flags = M_PKTHDR;
m->m_pkthdr.rcvif = NULL;
m->m_pkthdr.rdomain = 0;
SLIST_INIT(&m->m_pkthdr.tags);
m->m_pkthdr.csum_flags = 0;
m->m_pkthdr.ether_vtag = 0;
m->m_pkthdr.pf.hdr = NULL;
m->m_pkthdr.pf.statekey = NULL;
m->m_pkthdr.pf.rtableid = 0;
m->m_pkthdr.pf.qid = 0;
m->m_pkthdr.pf.tag = 0;
m->m_pkthdr.pf.flags = 0;
m->m_pkthdr.pf.routed = 0;
}
return (m);
}
struct mbuf *
m_inithdr(struct mbuf *m)
{
/* keep in sync with m_gethdr */
m->m_next = (struct mbuf *)NULL;
m->m_nextpkt = (struct mbuf *)NULL;
m->m_data = m->m_pktdat;
m->m_flags = M_PKTHDR;
m->m_pkthdr.rcvif = NULL;
m->m_pkthdr.rdomain = 0;
SLIST_INIT(&m->m_pkthdr.tags);
m->m_pkthdr.csum_flags = 0;
m->m_pkthdr.ether_vtag = 0;
m->m_pkthdr.pf.hdr = NULL;
m->m_pkthdr.pf.statekey = NULL;
m->m_pkthdr.pf.rtableid = 0;
m->m_pkthdr.pf.qid = 0;
m->m_pkthdr.pf.tag = 0;
m->m_pkthdr.pf.flags = 0;
m->m_pkthdr.pf.routed = 0;
return (m);
}
struct mbuf *
m_getclr(int nowait, int type)
{
struct mbuf *m;
MGET(m, nowait, type);
if (m == NULL)
return (NULL);
memset(mtod(m, caddr_t), 0, MLEN);
return (m);
}
int
m_clpool(u_int pktlen)
{
int pi;
for (pi = 0; pi < MCLPOOLS; pi++) {
if (pktlen <= mclsizes[pi])
return (pi);
}
return (-1);
}
void
m_clinitifp(struct ifnet *ifp)
{
struct mclpool *mclp = ifp->if_data.ifi_mclpool;
int i;
/* Initialize high water marks for use of cluster pools */
for (i = 0; i < MCLPOOLS; i++) {
mclp = &ifp->if_data.ifi_mclpool[i];
if (mclp->mcl_lwm == 0)
mclp->mcl_lwm = 2;
if (mclp->mcl_hwm == 0)
mclp->mcl_hwm = 32768;
mclp->mcl_cwm = MAX(4, mclp->mcl_lwm);
}
}
void
m_clsetwms(struct ifnet *ifp, u_int pktlen, u_int lwm, u_int hwm)
{
int pi;
pi = m_clpool(pktlen);
if (pi == -1)
return;
ifp->if_data.ifi_mclpool[pi].mcl_lwm = lwm;
ifp->if_data.ifi_mclpool[pi].mcl_hwm = hwm;
}
extern int m_clticks;
int m_livelock;
int
m_cldrop(struct ifnet *ifp, int pi)
{
static int liveticks;
struct mclpool *mclp;
extern int ticks;
int i;
if (m_livelock == 0 && ticks - m_clticks > 2) {
struct ifnet *aifp;
/*
* Timeout did not run, so we are in some kind of livelock.
* Decrease the cluster allocation high water marks on all
* interfaces and prevent them from growth for the very near
* future.
*/
m_livelock = 1;
ifp->if_data.ifi_livelocks++;
liveticks = ticks;
TAILQ_FOREACH(aifp, &ifnet, if_list) {
mclp = aifp->if_data.ifi_mclpool;
for (i = 0; i < MCLPOOLS; i++) {
mclp[i].mcl_cwm =
max(mclp[i].mcl_cwm / 2, mclp[i].mcl_lwm);
}
}
} else if (m_livelock && ticks - liveticks > 5)
m_livelock = 0; /* Let the high water marks grow again */
mclp = &ifp->if_data.ifi_mclpool[pi];
if (m_livelock == 0 && ISSET(ifp->if_flags, IFF_RUNNING) &&
mclp->mcl_alive <= 2 && mclp->mcl_cwm < mclp->mcl_hwm) {
/* About to run out, so increase the current watermark */
mclp->mcl_cwm++;
} else if (mclp->mcl_alive >= mclp->mcl_cwm)
return (1); /* No more packets given */
return (0);
}
void
m_clcount(struct ifnet *ifp, int pi)
{
ifp->if_data.ifi_mclpool[pi].mcl_alive++;
}
void
m_cluncount(struct mbuf *m, int all)
{
struct mbuf_ext *me;
do {
me = &m->m_ext;
if (((m->m_flags & (M_EXT|M_CLUSTER)) != (M_EXT|M_CLUSTER)) ||
(me->ext_ifp == NULL))
continue;
me->ext_ifp->if_data.ifi_mclpool[me->ext_backend].mcl_alive--;
me->ext_ifp = NULL;
} while (all && (m = m->m_next));
}
void
m_clget(struct mbuf *m, int how, struct ifnet *ifp, u_int pktlen)
{
int pi;
int s;
pi = m_clpool(pktlen);
#ifdef DIAGNOSTIC
if (pi == -1)
panic("m_clget: request for %u byte cluster", pktlen);
#endif
if (ifp != NULL && m_cldrop(ifp, pi))
return;
s = splnet();
m->m_ext.ext_buf = pool_get(&mclpools[pi],
how == M_WAIT ? PR_WAITOK : 0);
splx(s);
if (m->m_ext.ext_buf != NULL) {
m->m_data = m->m_ext.ext_buf;
m->m_flags |= M_EXT|M_CLUSTER;
m->m_ext.ext_size = mclpools[pi].pr_size;
m->m_ext.ext_free = NULL;
m->m_ext.ext_arg = NULL;
m->m_ext.ext_backend = pi;
m->m_ext.ext_ifp = ifp;
if (ifp != NULL)
m_clcount(ifp, pi);
MCLINITREFERENCE(m);
}
}
struct mbuf *
m_free(struct mbuf *m)
{
struct mbuf *n;
int s;
s = splnet();
mbstat.m_mtypes[m->m_type]--;
if (m->m_flags & M_PKTHDR)
m_tag_delete_chain(m);
if (m->m_flags & M_EXT)
m_extfree(m);
m->m_flags = 0;
n = m->m_next;
pool_put(&mbpool, m);
splx(s);
return (n);
}
void
m_extfree(struct mbuf *m)
{
if (MCLISREFERENCED(m)) {
m->m_ext.ext_nextref->m_ext.ext_prevref =
m->m_ext.ext_prevref;
m->m_ext.ext_prevref->m_ext.ext_nextref =
m->m_ext.ext_nextref;
} else if (m->m_flags & M_CLUSTER) {
m_cluncount(m, 0);
pool_put(&mclpools[m->m_ext.ext_backend],
m->m_ext.ext_buf);
} else if (m->m_ext.ext_free)
(*(m->m_ext.ext_free))(m->m_ext.ext_buf,
m->m_ext.ext_size, m->m_ext.ext_arg);
else
panic("unknown type of extension buffer");
m->m_ext.ext_size = 0;
m->m_flags &= ~(M_EXT|M_CLUSTER);
}
void
m_freem(struct mbuf *m)
{
struct mbuf *n;
if (m == NULL)
return;
do {
MFREE(m, n);
} while ((m = n) != NULL);
}
/*
* mbuf chain defragmenter. This function uses some evil tricks to defragment
* an mbuf chain into a single buffer without changing the mbuf pointer.
* This needs to know a lot of the mbuf internals to make this work.
*/
int
m_defrag(struct mbuf *m, int how)
{
struct mbuf *m0;
if (m->m_next == NULL)
return 0;
#ifdef DIAGNOSTIC
if (!(m->m_flags & M_PKTHDR))
panic("m_defrag: no packet hdr or not a chain");
#endif
if ((m0 = m_gethdr(how, m->m_type)) == NULL)
return -1;
if (m->m_pkthdr.len > MHLEN) {
MCLGETI(m0, how, NULL, m->m_pkthdr.len);
if (!(m0->m_flags & M_EXT)) {
m_free(m0);
return -1;
}
}
m_copydata(m, 0, m->m_pkthdr.len, mtod(m0, caddr_t));
m0->m_pkthdr.len = m0->m_len = m->m_pkthdr.len;
/* free chain behind and possible ext buf on the first mbuf */
m_freem(m->m_next);
m->m_next = NULL;
if (m->m_flags & M_EXT) {
int s = splnet();
m_extfree(m);
splx(s);
}
/*
* Bounce copy mbuf over to the original mbuf and set everything up.
* This needs to reset or clear all pointers that may go into the
* original mbuf chain.
*/
if (m0->m_flags & M_EXT) {
bcopy(&m0->m_ext, &m->m_ext, sizeof(struct mbuf_ext));
MCLINITREFERENCE(m);
m->m_flags |= M_EXT|M_CLUSTER;
m->m_data = m->m_ext.ext_buf;
} else {
m->m_data = m->m_pktdat;
bcopy(m0->m_data, m->m_data, m0->m_len);
}
m->m_pkthdr.len = m->m_len = m0->m_len;
m->m_pkthdr.pf.hdr = NULL; /* altq will cope */
m0->m_flags &= ~(M_EXT|M_CLUSTER); /* cluster is gone */
m_free(m0);
return 0;
}
/*
* Mbuffer utility routines.
*/
/*
* Ensure len bytes of contiguous space at the beginning of the mbuf chain
*/
struct mbuf *
m_prepend(struct mbuf *m, int len, int how)
{
struct mbuf *mn;
if (len > MHLEN)
panic("mbuf prepend length too big");
if (M_LEADINGSPACE(m) >= len) {
m->m_data -= len;
m->m_len += len;
} else {
MGET(mn, how, m->m_type);
if (mn == NULL) {
m_freem(m);
return (NULL);
}
if (m->m_flags & M_PKTHDR)
M_MOVE_PKTHDR(mn, m);
mn->m_next = m;
m = mn;
MH_ALIGN(m, len);
m->m_len = len;
}
if (m->m_flags & M_PKTHDR)
m->m_pkthdr.len += len;
return (m);
}
/*
* Make a copy of an mbuf chain starting "off" 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 off, int len, int wait)
{
return m_copym0(m, off, len, wait, 0); /* shallow copy on M_EXT */
}
/*
* m_copym2() is like m_copym(), except it COPIES cluster mbufs, instead
* of merely bumping the reference count.
*/
struct mbuf *
m_copym2(struct mbuf *m, int off, int len, int wait)
{
return m_copym0(m, off, len, wait, 1); /* deep copy */
}
struct mbuf *
m_copym0(struct mbuf *m, int off, int len, int wait, int deep)
{
struct mbuf *n, **np;
struct mbuf *top;
int copyhdr = 0;
if (off < 0 || len < 0)
panic("m_copym0: off %d, len %d", off, len);
if (off == 0 && m->m_flags & M_PKTHDR)
copyhdr = 1;
while (off > 0) {
if (m == NULL)
panic("m_copym0: null mbuf");
if (off < m->m_len)
break;
off -= m->m_len;
m = m->m_next;
}
np = ⊤
top = NULL;
while (len > 0) {
if (m == NULL) {
if (len != M_COPYALL)
panic("m_copym0: m == NULL and not COPYALL");
break;
}
MGET(n, wait, m->m_type);
*np = n;
if (n == NULL)
goto nospace;
if (copyhdr) {
M_DUP_PKTHDR(n, m);
if (len != M_COPYALL)
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 == NULL)
MCFail++;
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, caddr_t cp)
{
unsigned count;
if (off < 0)
panic("m_copydata: off %d < 0", off);
if (len < 0)
panic("m_copydata: len %d < 0", len);
while (off > 0) {
if (m == NULL)
panic("m_copydata: null mbuf in skip");
if (off < m->m_len)
break;
off -= m->m_len;
m = m->m_next;
}
while (len > 0) {
if (m == NULL)
panic("m_copydata: null mbuf");
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 data from a buffer back into the indicated mbuf chain,
* starting "off" bytes from the beginning, extending the mbuf
* chain if necessary. The mbuf needs to be properly initialized
* including the setting of m_len.
*/
void
m_copyback(struct mbuf *m0, int off, int len, const void *_cp)
{
int mlen, totlen = 0;
struct mbuf *m = m0, *n;
caddr_t cp = (caddr_t)_cp;
if (m0 == NULL)
return;
while (off > (mlen = m->m_len)) {
off -= mlen;
totlen += mlen;
if (m->m_next == NULL) {
if ((n = m_get(M_DONTWAIT, m->m_type)) == NULL)
goto out;
if (off + len > MLEN) {
MCLGETI(n, M_DONTWAIT, NULL, off + len);
if (!(n->m_flags & M_EXT)) {
m_free(n);
goto out;
}
}
bzero(mtod(n, caddr_t), off);
n->m_len = len + off;
m->m_next = n;
}
m = m->m_next;
}
while (len > 0) {
/* extend last packet to be filled fully */
if (m->m_next == NULL && (len > m->m_len - off))
m->m_len += min(len - (m->m_len - off),
M_TRAILINGSPACE(m));
mlen = min(m->m_len - off, len);
bcopy(cp, mtod(m, caddr_t) + off, (size_t)mlen);
cp += mlen;
len -= mlen;
totlen += mlen + off;
if (len == 0)
break;
off = 0;
if (m->m_next == NULL) {
if ((n = m_get(M_DONTWAIT, m->m_type)) == NULL)
goto out;
if (len > MLEN) {
MCLGETI(n, M_DONTWAIT, NULL, len);
if (!(n->m_flags & M_EXT)) {
m_free(n);
goto out;
}
}
n->m_len = 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;
}
/*
* 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.
* Therefore both chains should 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_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 */
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 == 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;
}
while ((m = m->m_next) != NULL)
m->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 == NULL)
goto bad;
m->m_len = 0;
if (n->m_flags & M_PKTHDR)
M_MOVE_PKTHDR(m, n);
}
space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
do {
count = min(min(max(len, max_protohdr), space), n->m_len);
bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
(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);
}
/*
* m_pullup2() works like m_pullup, save that len can be <= MCLBYTES.
* m_pullup2() only works on values of len such that MHLEN < len <= MCLBYTES,
* it calls m_pullup() for values <= MHLEN. It also only coagulates the
* reqested number of bytes. (For those of us who expect unwieldly option
* headers.
*
* KEBE SAYS: Remember that dtom() calls with data in clusters does not work!
*/
struct mbuf *
m_pullup2(struct mbuf *n, int len)
{
struct mbuf *m;
int count;
if (len <= MHLEN)
return m_pullup(n, len);
if ((n->m_flags & M_EXT) != 0 &&
n->m_data + len < &n->m_data[MCLBYTES] && n->m_next) {
if (n->m_len >= len)
return (n);
m = n;
n = n->m_next;
len -= m->m_len;
} else {
if (len > MCLBYTES)
goto bad;
MGET(m, M_DONTWAIT, n->m_type);
if (m == NULL)
goto bad;
MCLGET(m, M_DONTWAIT);
if ((m->m_flags & M_EXT) == 0) {
m_free(m);
goto bad;
}
m->m_len = 0;
if (n->m_flags & M_PKTHDR) {
/* Too many adverse side effects. */
/* M_MOVE_PKTHDR(m, n); */
m->m_flags = (n->m_flags & M_COPYFLAGS) |
M_EXT | M_CLUSTER;
M_MOVE_HDR(m, n);
/* n->m_data is cool. */
}
}
do {
count = min(len, 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;
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);
}
/*
* 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);
}
/*
* Inject a new mbuf chain of length siz in mbuf chain m0 at
* position len0. Returns a pointer to the first injected mbuf, or
* NULL on failure (m0 is left undisturbed). Note that if there is
* enough space for an object of size siz in the appropriate position,
* no memory will be allocated. Also, there will be no data movement in
* the first len0 bytes (pointers to that will remain valid).
*
* XXX It is assumed that siz is less than the size of an mbuf at the moment.
*/
struct mbuf *
m_inject(struct mbuf *m0, int len0, int siz, int wait)
{
struct mbuf *m, *n, *n2 = NULL, *n3;
unsigned len = len0, remain;
if ((siz >= MHLEN) || (len0 <= 0))
return (NULL);
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 (remain == 0) {
if ((m->m_next) && (M_LEADINGSPACE(m->m_next) >= siz)) {
m->m_next->m_len += siz;
if (m0->m_flags & M_PKTHDR)
m0->m_pkthdr.len += siz;
m->m_next->m_data -= siz;
return m->m_next;
}
} else {
n2 = m_copym2(m, len, remain, wait);
if (n2 == NULL)
return (NULL);
}
MGET(n, wait, MT_DATA);
if (n == NULL) {
if (n2)
m_freem(n2);
return (NULL);
}
n->m_len = siz;
if (m0->m_flags & M_PKTHDR)
m0->m_pkthdr.len += siz;
m->m_len -= remain; /* Trim */
if (n2) {
for (n3 = n; n3->m_next != NULL; n3 = n3->m_next)
;
n3->m_next = n2;
} else
n3 = n;
for (; n3->m_next != NULL; n3 = n3->m_next)
;
n3->m_next = m->m_next;
m->m_next = n;
return n;
}
/*
* 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, olen;
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);
M_DUP_PKTHDR(n, m0);
n->m_pkthdr.len -= len0;
olen = 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 == NULL) {
(void) m_free(n);
m0->m_pkthdr.len = olen;
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_ext = m->m_ext;
MCLADDREFERENCE(m, n);
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 off, struct ifnet *ifp,
void (*copy)(const void *, void *, size_t))
{
struct mbuf *m;
struct mbuf *top, **mp;
int len;
top = NULL;
mp = ⊤
if (off < 0 || off > MHLEN)
return (NULL);
MGETHDR(m, M_DONTWAIT, MT_DATA);
if (m == NULL)
return (NULL);
m->m_pkthdr.rcvif = ifp;
m->m_pkthdr.len = totlen;
len = MHLEN;
while (totlen > 0) {
if (top != NULL) {
MGET(m, M_DONTWAIT, MT_DATA);
if (m == NULL) {
m_freem(top);
return (NULL);
}
len = MLEN;
}
if (totlen + off >= MINCLSIZE) {
MCLGET(m, M_DONTWAIT);
if (m->m_flags & M_EXT)
len = MCLBYTES;
} else {
/* Place initial small packet/header at end of mbuf. */
if (top == NULL && totlen + off + max_linkhdr <= len) {
m->m_data += max_linkhdr;
len -= max_linkhdr;
}
}
if (off) {
m->m_data += off;
len -= off;
off = 0;
}
m->m_len = len = min(totlen, len);
if (copy)
copy(buf, mtod(m, caddr_t), (size_t)len);
else
bcopy(buf, mtod(m, caddr_t), (size_t)len);
buf += len;
*mp = m;
mp = &m->m_next;
totlen -= len;
}
return (top);
}
void
m_zero(struct mbuf *m)
{
while (m) {
#ifdef DIAGNOSTIC
if (M_READONLY(m))
panic("m_zero: M_READONLY");
#endif /* DIAGNOSTIC */
if (m->m_flags & M_EXT)
memset(m->m_ext.ext_buf, 0, m->m_ext.ext_size);
else {
if (m->m_flags & M_PKTHDR)
memset(m->m_pktdat, 0, MHLEN);
else
memset(m->m_dat, 0, MLEN);
}
m = m->m_next;
}
}
/*
* 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)(caddr_t, caddr_t, unsigned int), caddr_t fstate)
{
int rval;
unsigned int count;
if (len < 0)
panic("m_apply: len %d < 0", len);
if (off < 0)
panic("m_apply: off %d < 0", off);
while (off > 0) {
if (m == NULL)
panic("m_apply: null mbuf in skip");
if (off < m->m_len)
break;
off -= m->m_len;
m = m->m_next;
}
while (len > 0) {
if (m == NULL)
panic("m_apply: null mbuf");
count = min(m->m_len - off, len);
rval = f(fstate, mtod(m, caddr_t) + off, count);
if (rval)
return (rval);
len -= count;
off = 0;
m = m->m_next;
}
return (0);
}
int
m_leadingspace(struct mbuf *m)
{
if (M_READONLY(m))
return 0;
return (m->m_flags & M_EXT ? m->m_data - m->m_ext.ext_buf :
m->m_flags & M_PKTHDR ? m->m_data - m->m_pktdat :
m->m_data - m->m_dat);
}
int
m_trailingspace(struct mbuf *m)
{
if (M_READONLY(m))
return 0;
return (m->m_flags & M_EXT ? m->m_ext.ext_buf +
m->m_ext.ext_size - (m->m_data + m->m_len) :
&m->m_dat[MLEN] - (m->m_data + m->m_len));
}