4.3BSD-UWisc/src/sys/sys/uipc_mbuf.c
/*
* Copyright (c) 1982, 1986 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*
* @(#)uipc_mbuf.c 7.1 (Berkeley) 6/5/86
*/
#ifndef lint
static char rcs_id[] = {"$Header: uipc_mbuf.c,v 3.1 86/10/22 13:44:58 tadl Exp $"};
#endif not lint
/*
* RCS Info
* $Locker: $
*/
#include "../machine/pte.h"
#include "param.h"
#include "systm.h"
#include "user.h"
#include "proc.h"
#include "cmap.h"
#include "map.h"
#include "mbuf.h"
#include "vm.h"
#include "kernel.h"
#include "socketvar.h"
mbinit()
{
int s;
s = splimp();
if (m_clalloc(4096/CLBYTES, MPG_MBUFS, M_DONTWAIT) == 0)
goto bad;
if (m_clalloc(4096/CLBYTES, MPG_CLUSTERS, M_DONTWAIT) == 0)
goto bad;
splx(s);
return;
bad:
panic("mbinit");
}
/*
* Must be called at splimp.
*/
caddr_t
m_clalloc(ncl, how, canwait)
register int ncl;
int how;
{
int npg, mbx;
register struct mbuf *m;
register int i;
npg = ncl * CLSIZE;
mbx = rmalloc(mbmap, (long)npg);
if (mbx == 0) {
if (canwait == M_WAIT)
panic("out of mbufs: map full");
return (0);
}
m = cltom(mbx / CLSIZE);
if (memall(&Mbmap[mbx], npg, proc, CSYS) == 0) {
rmfree(mbmap, (long)npg, (long)mbx);
return (0);
}
vmaccess(&Mbmap[mbx], (caddr_t)m, npg);
switch (how) {
case MPG_CLUSTERS:
for (i = 0; i < ncl; i++) {
m->m_off = 0;
m->m_next = mclfree;
mclfree = m;
m += CLBYTES / sizeof (*m);
mbstat.m_clfree++;
}
mbstat.m_clusters += ncl;
break;
case MPG_MBUFS:
for (i = ncl * CLBYTES / sizeof (*m); i > 0; i--) {
m->m_off = 0;
m->m_type = MT_DATA;
mbstat.m_mtypes[MT_DATA]++;
mbstat.m_mbufs++;
(void) m_free(m);
m++;
}
break;
}
return ((caddr_t)m);
}
m_pgfree(addr, n)
caddr_t addr;
int n;
{
#ifdef lint
addr = addr; n = n;
#endif
}
/*
* Must be called at splimp.
*/
m_expand(canwait)
int canwait;
{
if (m_clalloc(1, MPG_MBUFS, canwait) == 0)
goto steal;
return (1);
steal:
/* should ask protocols to free code */
return (0);
}
/* NEED SOME WAY TO RELEASE SPACE */
/*
* Space allocation routines.
* These are also available as macros
* for critical paths.
*/
struct mbuf *
m_get(canwait, type)
int canwait, type;
{
register struct mbuf *m;
MGET(m, canwait, type);
return (m);
}
struct mbuf *
m_getclr(canwait, type)
int canwait, type;
{
register struct mbuf *m;
MGET(m, canwait, 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);
}
/*
* Get more mbufs; called from MGET macro if mfree list is empty.
* Must be called at splimp.
*/
/*ARGSUSED*/
struct mbuf *
m_more(canwait, type)
int canwait, type;
{
register struct mbuf *m;
while (m_expand(canwait) == 0) {
if (canwait == M_WAIT) {
m_want++;
sleep((caddr_t)&mfree, PZERO - 1);
} else {
mbstat.m_drops++;
return (NULL);
}
}
#define m_more(x,y) (panic("m_more"), (struct mbuf *)0)
MGET(m, canwait, type);
#undef m_more
return (m);
}
m_freem(m)
register struct mbuf *m;
{
register struct mbuf *n;
register int s;
if (m == NULL)
return;
s = splimp();
do {
MFREE(m, n);
} while (m = n);
splx(s);
}
/*
* Mbuffer utility routines.
*/
/*
* 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.
* Should get M_WAIT/M_DONTWAIT from caller.
*/
struct mbuf *
m_copy(m, off, len)
register struct mbuf *m;
int off;
register int len;
{
register struct mbuf *n, **np;
struct mbuf *top;
if (len == 0)
return (0);
if (off < 0 || len < 0)
panic("m_copy");
while (off > 0) {
if (m == 0)
panic("m_copy");
if (off < m->m_len)
break;
off -= m->m_len;
m = m->m_next;
}
np = ⊤
top = 0;
while (len > 0) {
if (m == 0) {
if (len != M_COPYALL)
panic("m_copy");
break;
}
MGET(n, M_DONTWAIT, m->m_type);
*np = n;
if (n == 0)
goto nospace;
n->m_len = MIN(len, m->m_len - off);
if (m->m_off > MMAXOFF && n->m_len > MLEN) {
mcldup(m, n, off);
n->m_off += off;
} 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;
}
return (top);
nospace:
m_freem(top);
return (0);
}
m_cat(m, n)
register struct mbuf *m, *n;
{
while (m->m_next)
m = m->m_next;
while (n) {
if (m->m_off >= MMAXOFF ||
m->m_off + m->m_len + n->m_len > MMAXOFF) {
/* 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);
}
}
m_adj(mp, len)
struct mbuf *mp;
register int len;
{
register struct mbuf *m;
register count;
if ((m = mp) == NULL)
return;
if (len >= 0) {
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_off += len;
break;
}
}
} 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;
return;
}
count -= len;
/*
* Correct length for chain is "count".
* Find the mbuf with last data, adjust its length,
* and toss data from remaining mbufs on chain.
*/
for (m = mp; 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 MPULL_EXTRA bytes to the
* contiguous region in an attempt to avoid being called next time.
*/
struct mbuf *
m_pullup(n, len)
register struct mbuf *n;
int len;
{
register struct mbuf *m;
register int count;
int space;
if (n->m_off + len <= MMAXOFF && n->m_next) {
m = n;
n = n->m_next;
len -= m->m_len;
} else {
if (len > MLEN)
goto bad;
MGET(m, M_DONTWAIT, n->m_type);
if (m == 0)
goto bad;
m->m_len = 0;
}
space = MMAXOFF - m->m_off;
do {
count = MIN(MIN(space - m->m_len, len + MPULL_EXTRA), 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_off += 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 (0);
}
/*
* Copy an mbuf to the contiguous area pointed to by cp.
* Skip <off> bytes and copy <len> bytes.
* Returns the number of bytes not transferred.
* The mbuf is NOT changed.
*/
int
m_cpytoc(m, off, len, cp)
register struct mbuf *m;
register int off, len;
register caddr_t cp;
{
register int ml;
if (m == NULL || off < 0 || len < 0 || cp == NULL)
panic("m_cpytoc");
while (off && m)
if (m->m_len <= off) {
off -= m->m_len;
m = m->m_next;
continue;
} else
break;
if (m == NULL)
return (len);
ml = imin(len, m->m_len - off);
bcopy(mtod(m, caddr_t)+off, cp, (u_int)ml);
cp += ml;
len -= ml;
m = m->m_next;
while (len && m) {
ml = m->m_len;
bcopy(mtod(m, caddr_t), cp, (u_int)ml);
cp += ml;
len -= ml;
m = m->m_next;
}
return (len);
}
/*
* Append a contiguous hunk of memory to a particular mbuf;
* that is, it does not follow the mbuf chain.
* XXX It should return 1 if it won't fit. Maybe someday.
*/
int
m_cappend(cp, len, m)
char *cp;
register int len;
register struct mbuf *m;
{
bcopy(cp, mtod(m, char *) + m->m_len, (u_int)len);
m->m_len += len;
return (0);
}
/*
* Tally the bytes used in an mbuf chain.
* op: -1 == subtract; 0 == assign; 1 == add;
*/
m_tally(m, op, cc, mbcnt)
register struct mbuf *m;
int op, *cc, *mbcnt;
{
struct sockbuf sockbuf;
register struct sockbuf *sb = &sockbuf;
bzero((caddr_t)sb, sizeof(*sb));
while (m) {
sballoc(sb, m);
m = m->m_next;
}
if (cc)
switch (op) {
case -1:
*cc -= sb->sb_cc;
break;
case 0:
*cc = sb->sb_cc;
break;
case 1:
*cc += sb->sb_cc;
break;
}
if (mbcnt)
switch (op) {
case -1:
*mbcnt -= sb->sb_mbcnt;
break;
case 0:
*mbcnt = sb->sb_mbcnt;
break;
case 1:
*mbcnt += sb->sb_mbcnt;
break;
}
}
#ifdef notdef
/*
* Given an mbuf, allocate and attach a cluster mbuf to it.
* Return 1 if successful, 0 otherwise.
* NOTE: m->m_len is set to CLBYTES!
*/
mclget(m)
register struct mbuf *m;
{
int ms;
register struct mbuf *p;
ms = splimp();
if (mclfree == 0)
/* XXX need a way to reclaim */
(void) m_clalloc(1, MPG_CLUSTERS);
if (p = mclfree) {
++mclrefcnt[mtocl(p)];
mbstat.m_clfree--;
mclfree = p->m_next;
m->m_len = CLBYTES;
m->m_off = (int)p - (int)m;
m->m_cltype = 1;
}
(void) splx(ms);
return (p ? 1 : 0);
}
#endif notdef
/* Allocate a "funny" mbuf, that is, one whose data is owned by someone else */
struct mbuf *
mclgetx(fun, arg, addr, len, wait)
int (*fun)(), arg, len, wait;
caddr_t addr;
{
register struct mbuf *m;
MGET(m, wait, MT_DATA);
if (m == 0)
return (0);
m->m_off = (int)addr - (int)m;
m->m_len = len;
m->m_cltype = 2;
m->m_clfun = fun;
m->m_clarg = arg;
m->m_clswp = NULL;
return (m);
}
/* Generic cluster mbuf unallocator -- invoked from within MFREE */
mclput(m)
register struct mbuf *m;
{
switch (m->m_cltype) {
case 1:
m = (struct mbuf *)(mtod(m, int) & ~(CLBYTES - 1));
if (--mclrefcnt[mtocl(m)] == 0) {
m->m_next = mclfree;
mclfree = m;
mbstat.m_clfree++;
}
break;
case 2:
(*m->m_clfun)(m->m_clarg);
break;
default:
panic("mclput");
}
}
/* Internal routine used for mcldup on funny mbufs */
static
buffree(arg)
int arg;
{
extern int kmem_free_intr();
kmem_free_intr((caddr_t)arg, *(u_int *)arg);
}
/*
* Generic cluster mbuf duplicator
* which duplicates <m> into <n>.
* If <m> is a regular cluster mbuf, mcldup simply
* bumps the reference count and ignores <off>.
* If <m> is a funny mbuf, mcldup allocates a chunck
* kernel memory and makes a copy, starting at <off>.
* XXX does not set the m_len field in <n>!
*/
mcldup(m, n, off)
register struct mbuf *m, *n;
int off;
{
register struct mbuf *p;
register caddr_t copybuf;
switch (m->m_cltype) {
case 1:
p = mtod(m, struct mbuf *);
n->m_off = (int)p - (int)n;
n->m_cltype = 1;
mclrefcnt[mtocl(p)]++;
break;
case 2:
copybuf = (caddr_t)kmem_alloc((u_int)(n->m_len + sizeof(int)));
* (int *) copybuf = n->m_len + sizeof (int);
bcopy(mtod(m, caddr_t) + off, copybuf + sizeof (int),
(unsigned)n->m_len);
n->m_off = (int)copybuf + sizeof (int) - (int)n - off;
n->m_cltype = 2;
n->m_clfun = buffree;
n->m_clarg = (int)copybuf;
n->m_clswp = NULL;
break;
default:
panic("mcldup");
}
}
/*
* Move an mbuf chain to contiguous locations.
* Checks for possibility of page exchange to accomplish move.
* Free chain when moved.
*/
m_movtoc(m, to, count)
register struct mbuf *m;
register caddr_t to;
register int count;
{
register struct mbuf *m0;
register caddr_t from;
register int i;
while (m != NULL) {
i = MIN(m->m_len, count);
from = mtod(m, caddr_t);
if (i >= CLBYTES && m->m_cltype == 2 && m->m_clswp &&
(((int)from | (int)to) & (CLBYTES-1)) == 0 &&
(*m->m_clswp)(m->m_clarg, from, to)) {
i -= CLBYTES;
from += CLBYTES;
to += CLBYTES;
}
if (i > 0) {
bcopy(from, to, (unsigned)i);
count -= i;
to += i;
}
m0 = m;
MFREE(m0, m);
}
return (count);
}