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/*
* Copyright (c) 1995 Danny Gasparovski
*
* Please read the file COPYRIGHT for the
* terms and conditions of the copyright.
*/
/*
* mbuf's in SLiRP are much simpler than the real mbufs in
* FreeBSD. They are fixed size, determined by the MTU,
* so that one whole packet can fit. Mbuf's cannot be
* chained together. If there's more data than the mbuf
* could hold, an external g_malloced buffer is pointed to
* by m_ext (and the data pointers) and M_EXT is set in
* the flags
*/
#include "slirp.h"
#define MBUF_THRESH 30
/*
* Find a nice value for msize
*/
#define SLIRP_MSIZE\
(offsetof(struct mbuf, m_dat) + IF_MAXLINKHDR + TCPIPHDR_DELTA + IF_MTU)
void
m_init(Slirp *slirp)
{
slirp->m_freelist.qh_link = slirp->m_freelist.qh_rlink = &slirp->m_freelist;
slirp->m_usedlist.qh_link = slirp->m_usedlist.qh_rlink = &slirp->m_usedlist;
}
void m_cleanup(Slirp *slirp)
{
struct mbuf *m, *next;
m = (struct mbuf *) slirp->m_usedlist.qh_link;
while ((struct quehead *) m != &slirp->m_usedlist) {
next = m->m_next;
if (m->m_flags & M_EXT) {
g_free(m->m_ext);
}
g_free(m);
m = next;
}
m = (struct mbuf *) slirp->m_freelist.qh_link;
while ((struct quehead *) m != &slirp->m_freelist) {
next = m->m_next;
g_free(m);
m = next;
}
}
/*
* Get an mbuf from the free list, if there are none
* allocate one
*
* Because fragmentation can occur if we alloc new mbufs and
* free old mbufs, we mark all mbufs above mbuf_thresh as M_DOFREE,
* which tells m_free to actually g_free() it
*/
struct mbuf *
m_get(Slirp *slirp)
{
register struct mbuf *m;
int flags = 0;
DEBUG_CALL("m_get");
if (slirp->m_freelist.qh_link == &slirp->m_freelist) {
m = g_malloc(SLIRP_MSIZE);
slirp->mbuf_alloced++;
if (slirp->mbuf_alloced > MBUF_THRESH)
flags = M_DOFREE;
m->slirp = slirp;
} else {
m = (struct mbuf *) slirp->m_freelist.qh_link;
remque(m);
}
/* Insert it in the used list */
insque(m,&slirp->m_usedlist);
m->m_flags = (flags | M_USEDLIST);
/* Initialise it */
m->m_size = SLIRP_MSIZE - offsetof(struct mbuf, m_dat);
m->m_data = m->m_dat;
m->m_len = 0;
m->m_nextpkt = NULL;
m->m_prevpkt = NULL;
m->resolution_requested = false;
m->expiration_date = (uint64_t)-1;
DEBUG_ARG("m = %p", m);
return m;
}
void
m_free(struct mbuf *m)
{
DEBUG_CALL("m_free");
DEBUG_ARG("m = %p", m);
if(m) {
/* Remove from m_usedlist */
if (m->m_flags & M_USEDLIST)
remque(m);
/* If it's M_EXT, free() it */
if (m->m_flags & M_EXT) {
g_free(m->m_ext);
}
/*
* Either free() it or put it on the free list
*/
if (m->m_flags & M_DOFREE) {
m->slirp->mbuf_alloced--;
g_free(m);
} else if ((m->m_flags & M_FREELIST) == 0) {
insque(m,&m->slirp->m_freelist);
m->m_flags = M_FREELIST; /* Clobber other flags */
}
} /* if(m) */
}
/*
* Copy data from one mbuf to the end of
* the other.. if result is too big for one mbuf, allocate
* an M_EXT data segment
*/
void
m_cat(struct mbuf *m, struct mbuf *n)
{
/*
* If there's no room, realloc
*/
if (M_FREEROOM(m) < n->m_len)
m_inc(m, m->m_len + n->m_len);
memcpy(m->m_data+m->m_len, n->m_data, n->m_len);
m->m_len += n->m_len;
m_free(n);
}
/* make m 'size' bytes large from m_data */
void
m_inc(struct mbuf *m, int size)
{
int gapsize;
/* some compilers throw up on gotos. This one we can fake. */
if (M_ROOM(m) > size) {
return;
}
if (m->m_flags & M_EXT) {
gapsize = m->m_data - m->m_ext;
m->m_ext = g_realloc(m->m_ext, size + gapsize);
} else {
gapsize = m->m_data - m->m_dat;
m->m_ext = g_malloc(size + gapsize);
memcpy(m->m_ext, m->m_dat, m->m_size);
m->m_flags |= M_EXT;
}
m->m_data = m->m_ext + gapsize;
m->m_size = size + gapsize;
}
void
m_adj(struct mbuf *m, int len)
{
if (m == NULL)
return;
if (len >= 0) {
/* Trim from head */
m->m_data += len;
m->m_len -= len;
} else {
/* Trim from tail */
len = -len;
m->m_len -= len;
}
}
/*
* Copy len bytes from m, starting off bytes into n
*/
int
m_copy(struct mbuf *n, struct mbuf *m, int off, int len)
{
if (len > M_FREEROOM(n))
return -1;
memcpy((n->m_data + n->m_len), (m->m_data + off), len);
n->m_len += len;
return 0;
}
/*
* Given a pointer into an mbuf, return the mbuf
* XXX This is a kludge, I should eliminate the need for it
* Fortunately, it's not used often
*/
struct mbuf *
dtom(Slirp *slirp, void *dat)
{
struct mbuf *m;
DEBUG_CALL("dtom");
DEBUG_ARG("dat = %p", dat);
/* bug corrected for M_EXT buffers */
for (m = (struct mbuf *) slirp->m_usedlist.qh_link;
(struct quehead *) m != &slirp->m_usedlist;
m = m->m_next) {
if (m->m_flags & M_EXT) {
if( (char *)dat>=m->m_ext && (char *)dat<(m->m_ext + m->m_size) )
return m;
} else {
if( (char *)dat >= m->m_dat && (char *)dat<(m->m_dat + m->m_size) )
return m;
}
}
DEBUG_ERROR("dtom failed");
return (struct mbuf *)0;
}
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