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[unix-history] / usr / src / sys / kern / uipc_mbuf.c
/*
* Copyright (c) 1982, 1986, 1988, 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* %sccs.include.redist.c%
*
* @(#)uipc_mbuf.c 8.4 (Berkeley) %G%
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/map.h>
#define MBTYPES
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <vm/vm.h>
extern vm_map_t mb_map;
struct mbuf *mbutl;
char *mclrefcnt;
void
mbinit()
{
int s;
s = splimp();
if (m_clalloc(max(4096/CLBYTES, 1), M_DONTWAIT) == 0)
goto bad;
splx(s);
return;
bad:
panic("mbinit");
}
/*
* Allocate some number of mbuf clusters
* and place on cluster free list.
* Must be called at splimp.
*/
/* ARGSUSED */
int
m_clalloc(ncl, nowait)
register int ncl;
int nowait;
{
static int logged;
register caddr_t p;
register int i;
int npg;
npg = ncl * CLSIZE;
p = (caddr_t)kmem_malloc(mb_map, ctob(npg), !nowait);
if (p == NULL) {
if (logged == 0) {
logged++;
log(LOG_ERR, "mb_map full\n");
}
return (0);
}
ncl = ncl * CLBYTES / MCLBYTES;
for (i = 0; i < ncl; i++) {
((union mcluster *)p)->mcl_next = mclfree;
mclfree = (union mcluster *)p;
p += MCLBYTES;
mbstat.m_clfree++;
}
mbstat.m_clusters += ncl;
return (1);
}
/*
* When MGET failes, ask protocols to free space when short of memory,
* then re-attempt to allocate an mbuf.
*/
struct mbuf *
m_retry(i, t)
int i, t;
{
register struct mbuf *m;
m_reclaim();
#define m_retry(i, t) (struct mbuf *)0
MGET(m, i, t);
#undef m_retry
return (m);
}
/*
* As above; retry an MGETHDR.
*/
struct mbuf *
m_retryhdr(i, t)
int i, t;
{
register struct mbuf *m;
m_reclaim();
#define m_retryhdr(i, t) (struct mbuf *)0
MGETHDR(m, i, t);
#undef m_retryhdr
return (m);
}
void
m_reclaim()
{
register struct domain *dp;
register struct protosw *pr;
int s = splimp();
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)();
splx(s);
mbstat.m_drain++;
}
/*
* Space allocation routines.
* These are also available as macros
* for critical paths.
*/
struct mbuf *
m_get(nowait, type)
int nowait, type;
{
register struct mbuf *m;
MGET(m, nowait, type);
return (m);
}
struct mbuf *
m_gethdr(nowait, type)
int nowait, type;
{
register struct mbuf *m;
MGETHDR(m, nowait, type);
return (m);
}
struct mbuf *
m_getclr(nowait, type)
int nowait, type;
{
register struct mbuf *m;
MGET(m, nowait, type);
if (m == 0)
return (0);
bzero(mtod(m, caddr_t), MLEN);
return (m);
}
struct mbuf *
m_free(m)
struct mbuf *m;
{
register struct mbuf *n;
MFREE(m, n);
return (n);
}
void
m_freem(m)
register struct mbuf *m;
{
register struct mbuf *n;
if (m == NULL)
return;
do {
MFREE(m, n);
} while (m = n);
}
/*
* Mbuffer utility routines.
*/
/*
* Lesser-used path for M_PREPEND:
* allocate new mbuf to prepend to chain,
* copy junk along.
*/
struct mbuf *
m_prepend(m, len, how)
register struct mbuf *m;
int len, 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->m_flags &= ~M_PKTHDR;
}
mn->m_next = m;
m = mn;
if (len < MHLEN)
MH_ALIGN(m, len);
m->m_len = len;
return (m);
}
/*
* Make a copy of an mbuf chain starting "off0" bytes from the beginning,
* continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf.
* The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller.
*/
int MCFail;
struct mbuf *
m_copym(m, off0, len, wait)
register struct mbuf *m;
int off0, wait;
register int len;
{
register struct mbuf *n, **np;
register int off = off0;
struct mbuf *top;
int copyhdr = 0;
if (off < 0 || len < 0)
panic("m_copym");
if (off == 0 && m->m_flags & M_PKTHDR)
copyhdr = 1;
while (off > 0) {
if (m == 0)
panic("m_copym");
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");
break;
}
MGET(n, wait, m->m_type);
*np = n;
if (n == 0)
goto nospace;
if (copyhdr) {
M_COPY_PKTHDR(n, m);
if (len == M_COPYALL)
n->m_pkthdr.len -= off0;
else
n->m_pkthdr.len = len;
copyhdr = 0;
}
n->m_len = min(len, m->m_len - off);
if (m->m_flags & M_EXT) {
n->m_data = m->m_data + off;
mclrefcnt[mtocl(m->m_ext.ext_buf)]++;
n->m_ext = m->m_ext;
n->m_flags |= M_EXT;
} else
bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
(unsigned)n->m_len);
if (len != M_COPYALL)
len -= n->m_len;
off = 0;
m = m->m_next;
np = &n->m_next;
}
if (top == 0)
MCFail++;
return (top);
nospace:
m_freem(top);
MCFail++;
return (0);
}
/*
* Copy data from an mbuf chain starting "off" bytes from the beginning,
* continuing for "len" bytes, into the indicated buffer.
*/
void
m_copydata(m, off, len, cp)
register struct mbuf *m;
register int off;
register int len;
caddr_t cp;
{
register unsigned count;
if (off < 0 || len < 0)
panic("m_copydata");
while (off > 0) {
if (m == 0)
panic("m_copydata");
if (off < m->m_len)
break;
off -= m->m_len;
m = m->m_next;
}
while (len > 0) {
if (m == 0)
panic("m_copydata");
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;
}
}
/*
* Concatenate mbuf chain n to m.
* Both chains must be of the same type (e.g. MT_DATA).
* Any m_pkthdr is not updated.
*/
void
m_cat(m, n)
register struct mbuf *m, *n;
{
while (m->m_next)
m = m->m_next;
while (n) {
if (m->m_flags & M_EXT ||
m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) {
/* just join the two chains */
m->m_next = n;
return;
}
/* splat the data from one into the other */
bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
(u_int)n->m_len);
m->m_len += n->m_len;
n = m_free(n);
}
}
void
m_adj(mp, req_len)
struct mbuf *mp;
int req_len;
{
register int len = req_len;
register struct mbuf *m;
register 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->m_next)
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(n, len)
register struct mbuf *n;
int len;
{
register struct mbuf *m;
register 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;
m->m_len = 0;
if (n->m_flags & M_PKTHDR) {
M_COPY_PKTHDR(m, n);
n->m_flags &= ~M_PKTHDR;
}
}
space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
do {
count = min(min(max(len, max_protohdr), space), n->m_len);
bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
(unsigned)count);
len -= count;
m->m_len += count;
n->m_len -= count;
space -= count;
if (n->m_len)
n->m_data += count;
else
n = m_free(n);
} while (len > 0 && n);
if (len > 0) {
(void) m_free(m);
goto bad;
}
m->m_next = n;
return (m);
bad:
m_freem(n);
MPFail++;
return (0);
}
/*
* 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(m0, len0, wait)
register struct mbuf *m0;
int len0, wait;
{
register struct mbuf *m, *n;
unsigned len = len0, remain;
for (m = m0; m && len > m->m_len; m = m->m_next)
len -= m->m_len;
if (m == 0)
return (0);
remain = m->m_len - len;
if (m0->m_flags & M_PKTHDR) {
MGETHDR(n, wait, m0->m_type);
if (n == 0)
return (0);
n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
n->m_pkthdr.len = m0->m_pkthdr.len - len0;
m0->m_pkthdr.len = len0;
if (m->m_flags & M_EXT)
goto extpacket;
if (remain > MHLEN) {
/* m can't be the lead packet */
MH_ALIGN(n, 0);
n->m_next = m_split(m, len, wait);
if (n->m_next == 0) {
(void) m_free(n);
return (0);
} 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 (0);
M_ALIGN(n, remain);
}
extpacket:
if (m->m_flags & M_EXT) {
n->m_flags |= M_EXT;
n->m_ext = m->m_ext;
mclrefcnt[mtocl(m->m_ext.ext_buf)]++;
m->m_ext.ext_size = 0; /* For Accounting XXXXXX danger */
n->m_data = m->m_data + len;
} else {
bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain);
}
n->m_len = remain;
m->m_len = len;
n->m_next = m->m_next;
m->m_next = 0;
return (n);
}
/*
* Routine to copy from device local memory into mbufs.
*/
struct mbuf *
m_devget(buf, totlen, off0, ifp, copy)
char *buf;
int totlen, off0;
struct ifnet *ifp;
void (*copy)();
{
register struct mbuf *m;
struct mbuf *top = 0, **mp = &top;
register int off = off0, len;
register 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 (0);
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 (0);
}
m->m_len = MLEN;
}
len = min(totlen, epkt - cp);
if (len >= MINCLSIZE) {
MCLGET(m, M_DONTWAIT);
if (m->m_flags & M_EXT)
m->m_len = len = min(len, MCLBYTES);
else
len = m->m_len;
} else {
/*
* Place initial small packet/header at end of mbuf.
*/
if (len < m->m_len) {
if (top == 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), (unsigned)len);
else
bcopy(cp, mtod(m, caddr_t), (unsigned)len);
cp += len;
*mp = m;
mp = &m->m_next;
totlen -= len;
if (cp == epkt)
cp = buf;
}
return (top);
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.