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/*
* Copyright (c) 1995 Danny Gasparovski.
*
* Please read the file COPYRIGHT for the
* terms and conditions of the copyright.
*/
#include "qemu/osdep.h"
#include "slirp.h"
static void sbappendsb(struct sbuf *sb, struct mbuf *m);
void
sbfree(struct sbuf *sb)
{
free(sb->sb_data);
}
bool
sbdrop(struct sbuf *sb, int num)
{
int limit = sb->sb_datalen / 2;
/*
* We can only drop how much we have
* This should never succeed
*/
if(num > sb->sb_cc)
num = sb->sb_cc;
sb->sb_cc -= num;
sb->sb_rptr += num;
if(sb->sb_rptr >= sb->sb_data + sb->sb_datalen)
sb->sb_rptr -= sb->sb_datalen;
if (sb->sb_cc < limit && sb->sb_cc + num >= limit) {
return true;
}
return false;
}
void
sbreserve(struct sbuf *sb, int size)
{
if (sb->sb_data) {
/* Already alloced, realloc if necessary */
if (sb->sb_datalen != size) {
sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)realloc(sb->sb_data, size);
sb->sb_cc = 0;
if (sb->sb_wptr)
sb->sb_datalen = size;
else
sb->sb_datalen = 0;
}
} else {
sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)malloc(size);
sb->sb_cc = 0;
if (sb->sb_wptr)
sb->sb_datalen = size;
else
sb->sb_datalen = 0;
}
}
/*
* Try and write() to the socket, whatever doesn't get written
* append to the buffer... for a host with a fast net connection,
* this prevents an unnecessary copy of the data
* (the socket is non-blocking, so we won't hang)
*/
void
sbappend(struct socket *so, struct mbuf *m)
{
int ret = 0;
DEBUG_CALL("sbappend");
DEBUG_ARG("so = %p", so);
DEBUG_ARG("m = %p", m);
DEBUG_ARG("m->m_len = %d", m->m_len);
/* Shouldn't happen, but... e.g. foreign host closes connection */
if (m->m_len <= 0) {
m_free(m);
return;
}
/*
* If there is urgent data, call sosendoob
* if not all was sent, sowrite will take care of the rest
* (The rest of this function is just an optimisation)
*/
if (so->so_urgc) {
sbappendsb(&so->so_rcv, m);
m_free(m);
(void)sosendoob(so);
return;
}
/*
* We only write if there's nothing in the buffer,
* ottherwise it'll arrive out of order, and hence corrupt
*/
if (!so->so_rcv.sb_cc)
ret = slirp_send(so, m->m_data, m->m_len, 0);
if (ret <= 0) {
/*
* Nothing was written
* It's possible that the socket has closed, but
* we don't need to check because if it has closed,
* it will be detected in the normal way by soread()
*/
sbappendsb(&so->so_rcv, m);
} else if (ret != m->m_len) {
/*
* Something was written, but not everything..
* sbappendsb the rest
*/
m->m_len -= ret;
m->m_data += ret;
sbappendsb(&so->so_rcv, m);
} /* else */
/* Whatever happened, we free the mbuf */
m_free(m);
}
/*
* Copy the data from m into sb
* The caller is responsible to make sure there's enough room
*/
static void
sbappendsb(struct sbuf *sb, struct mbuf *m)
{
int len, n, nn;
len = m->m_len;
if (sb->sb_wptr < sb->sb_rptr) {
n = sb->sb_rptr - sb->sb_wptr;
if (n > len) n = len;
memcpy(sb->sb_wptr, m->m_data, n);
} else {
/* Do the right edge first */
n = sb->sb_data + sb->sb_datalen - sb->sb_wptr;
if (n > len) n = len;
memcpy(sb->sb_wptr, m->m_data, n);
len -= n;
if (len) {
/* Now the left edge */
nn = sb->sb_rptr - sb->sb_data;
if (nn > len) nn = len;
memcpy(sb->sb_data,m->m_data+n,nn);
n += nn;
}
}
sb->sb_cc += n;
sb->sb_wptr += n;
if (sb->sb_wptr >= sb->sb_data + sb->sb_datalen)
sb->sb_wptr -= sb->sb_datalen;
}
/*
* Copy data from sbuf to a normal, straight buffer
* Don't update the sbuf rptr, this will be
* done in sbdrop when the data is acked
*/
void
sbcopy(struct sbuf *sb, int off, int len, char *to)
{
char *from;
from = sb->sb_rptr + off;
if (from >= sb->sb_data + sb->sb_datalen)
from -= sb->sb_datalen;
if (from < sb->sb_wptr) {
if (len > sb->sb_cc) len = sb->sb_cc;
memcpy(to,from,len);
} else {
/* re-use off */
off = (sb->sb_data + sb->sb_datalen) - from;
if (off > len) off = len;
memcpy(to,from,off);
len -= off;
if (len)
memcpy(to+off,sb->sb_data,len);
}
}
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