/* uipc_mbuf.c 1.6 81/10/30 */

#include "../h/param.h"
#include "../h/dir.h"
#include "../h/user.h"
#include "../h/proc.h"
#include "../h/pte.h"
#include "../h/cmap.h"
#include "../h/map.h"
#include "../h/mbuf.h"
#include "../inet/inet.h"
#include "../inet/inet_systm.h"
#include "../inet/ip.h"
#include "../inet/tcp.h"
#include "../h/vm.h"

struct mbuf *
m_get(canwait)
	int canwait;
{
	register struct mbuf *m;

COUNT(M_GET);
	MGET(m, canwait);
	return (m);
}

struct mbuf *
m_free(m)
	struct mbuf *m;
{
	register struct mbuf *n;

COUNT(M_FREE);
	MFREE(m, n);
	return (n);
}

struct mbuf *
m_more(type)
	int type;
{
	int s;
	register struct mbuf *m;

COUNT(M_MORE);
	if (!m_expand()) {
		netstat.m_drops++;
		return (NULL);
	}
#define m_more(x) ((struct mbuf *)panic("m_more"))
	MGET(m, 0);
	return (m);
}

m_freem(m)
	register struct mbuf *m;
{
	register struct mbuf *n;
	register int s, cnt;

COUNT(M_FREEM);
	if (m == NULL)
		return (0);
	cnt = 0;
	s = splimp();
	do {
		if (m->m_off > MMAXOFF)
			cnt += NMBPG;
		cnt++;
		MFREE(m, n);
	} while (m = n);
	splx(s);
	return (cnt);
}

mbufinit()
{
	register struct mbuf *m;
	register i;

COUNT(MBUFINIT);
	m = (struct mbuf *)&netutl[0];  /* ->start of buffer virt mem */
	vmemall(&Netmap[0], 2, proc, CSYS);
	vmaccess(&Netmap[0], m, 2);
	for (i=0; i < NMBPG; i++) {
		m->m_off = 0;
		m_free(m);
		m++;
	}
	pg_alloc(3);
	mbstat.m_pages = 4;
	mbstat.m_bufs = 32;
	mbstat.m_lowat = 16;
	mbstat.m_hiwat = 32;
	{ int i,j,k,n;
	n = 32;
	k = n << 1;
	if ((i = rmalloc(netmap, n)) == 0)
		return (0);
	j = i<<1;
	m = pftom(i);
	/* should use vmemall sometimes */
	if (memall(&Netmap[j], k, proc, CSYS) == 0) {
		printf("botch\n");
		return;
	}
	vmaccess(&Netmap[j], (caddr_t)m, k);
	for (j=0; j < n; j++) {
		m->m_off = 0;
		m->m_next = mpfree;
		mpfree = m;
		m += NMBPG;
		nmpfree++;
	}
	}
}

pg_alloc(n)
	register int n;
{
	register i, j, k;
	register struct mbuf *m;
	int bufs, s;

COUNT(PG_ALLOC);
	k = n << 1;
	if ((i = rmalloc(netmap, n)) == 0)
		return (0);
	j = i<<1;
	m = pftom(i);
	/* should use vmemall sometimes */
	if (memall(&Netmap[j], k, proc, CSYS) == 0)
		return (0);
	vmaccess(&Netmap[j], (caddr_t)m, k);
	bufs = n << 3;
	s = splimp();
	for (j=0; j < bufs; j++) {
		m->m_off = 0;
		m_free(m);
		m++;
	}
	splx(s);
	mbstat.m_pages += n;
	return (1);
}

m_expand()
{
	register i;
	register struct mbuf *m, *n;
	int need, needp, needs;

COUNT(M_EXPAND);
	needs = need = mbstat.m_hiwat - mbstat.m_bufs;
	needp = need >> 3;
	if (pg_alloc(needp))
		return (1);
	for (i=0; i < needp; i++, need -= NMBPG)
		if (pg_alloc(1) == 0)
			goto steal;
	return (need < needs);
steal:
	/* while (not enough) ask protocols to free code */
	;
}

#ifdef notdef
m_relse()
{

COUNT(M_RELSE);
}
#endif

m_cat(m, n)
	register struct mbuf *m, *n;
{

	while (m->m_next)
		m = m->m_next;
	while (n)
		if (m->m_off + m->m_len + n->m_len <= MMAXOFF) {
			bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, n->m_len);
			m->m_len += n->m_len;
			n = m_free(n);
		} else {
			m->m_next = n;
			m = n;
			n = m->m_next;
		}
}

m_adj(mp, len)
	struct mbuf *mp;
	register len;
{
	register struct mbuf *m, *n;

/*
	for (m = mp; m; m = m->m_next) {
		printf("a %x %d\n", m, m->m_len);
	}
*/
COUNT(M_ADJ);
	if ((m = mp) == NULL)
		return;
	if (len >= 0) {                 /* adjust from top of msg chain */
		while (m != NULL && len > 0) {
			if (m->m_len <= len) {          /* free this mbuf */
				len -= m->m_len;
				m->m_len = 0;
				m = m->m_next;
			} else {                        /* adjust mbuf */
				m->m_len -= len;
				m->m_off += len;
				break;
			}
		}

	} else {                        /* adjust from bottom of msg chain */
		len = -len;
		while (len > 0 && m->m_len != 0) {
			/* find end of chain */
			while (m != NULL && m->m_len != 0) {
				n = m;
				m = m->m_next;
			}
			if (n->m_len <= len) {          /* last mbuf */
				len -= n->m_len;
				n->m_len = 0;
				m = mp;
			} else {                        /* adjust length */
				n->m_len -= len;
				break;
			}
		}
	}
}

/*
 * convert mbuf virtual to physical addr for uballoc
 */
mtophys(m)
	register struct mbuf *m;
{
	register i;
	register unsigned long addr;
	register struct pte *pte;

COUNT(MTOPHYS);
	i = (((int)m & ~PGOFSET) - (int)netutl) >> PGSHIFT;
	pte = &Netmap[i];
	addr = (pte->pg_pfnum << PGSHIFT) | ((int)m & PGOFSET);
	return (addr);
}