freebsd-dev/contrib/ntp/libntp/recvbuff.c
2000-01-28 14:55:50 +00:00

260 lines
4.5 KiB
C

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdio.h>
#include "ntp_machine.h"
#include "ntp_fp.h"
#include "ntp_stdlib.h"
#include "ntp_syslog.h"
#include "ntp_io.h"
#include "recvbuff.h"
#include "iosignal.h"
/*
* Memory allocation
*/
static u_long volatile full_recvbufs; /* number of recvbufs on fulllist */
static u_long volatile free_recvbufs; /* number of recvbufs on freelist */
static u_long volatile total_recvbufs; /* total recvbufs currently in use */
static u_long volatile lowater_adds; /* number of times we have added memory */
static struct recvbuf *volatile freelist; /* free buffers */
static struct recvbuf *volatile fulllist; /* lifo buffers with data */
static struct recvbuf *volatile beginlist; /* fifo buffers with data */
#if defined(HAVE_IO_COMPLETION_PORT)
static CRITICAL_SECTION RecvCritSection;
# define RECV_BLOCK_IO() EnterCriticalSection(&RecvCritSection)
# define RECV_UNBLOCK_IO() LeaveCriticalSection(&RecvCritSection)
#else
# define RECV_BLOCK_IO()
# define RECV_UNBLOCK_IO()
#endif
u_long
free_recvbuffs (void)
{
return free_recvbufs;
}
u_long
full_recvbuffs (void)
{
return free_recvbufs;
}
u_long
total_recvbuffs (void)
{
return free_recvbufs;
}
u_long
lowater_additions(void)
{
return lowater_adds;
}
static void
initialise_buffer(struct recvbuf *buff)
{
memset((char *) buff, 0, sizeof(struct recvbuf));
#if defined HAVE_IO_COMPLETION_PORT
buff->iocompletioninfo.overlapped.hEvent = CreateEvent(NULL, FALSE,FALSE, NULL);
buff->wsabuff.len = RX_BUFF_SIZE;
buff->wsabuff.buf = (char *) buff->recv_buffer;
#endif
}
static void
create_buffers(void)
{
register struct recvbuf *buf;
int i;
buf = (struct recvbuf *)
emalloc(RECV_INC*sizeof(struct recvbuf));
for (i = 0; i < RECV_INC; i++)
{
initialise_buffer(buf);
buf->next = (struct recvbuf *) freelist;
freelist = buf;
buf++;
}
free_recvbufs += RECV_INC;
total_recvbufs += RECV_INC;
lowater_adds++;
}
void
init_recvbuff(int nbufs)
{
register struct recvbuf *buf;
int i;
/*
* Init buffer free list and stat counters
*/
freelist = 0;
buf = (struct recvbuf *)
emalloc(nbufs*sizeof(struct recvbuf));
for (i = 0; i < nbufs; i++)
{
initialise_buffer(buf);
buf->next = (struct recvbuf *) freelist;
freelist = buf;
buf++;
}
fulllist = 0;
free_recvbufs = total_recvbufs = nbufs;
full_recvbufs = lowater_adds = 0;
#if defined(HAVE_IO_COMPLETION_PORT)
InitializeCriticalSection(&RecvCritSection);
#endif
}
/*
* getrecvbufs - get receive buffers which have data in them
*
*
*/
struct recvbuf *
getrecvbufs(void)
{
struct recvbuf *rb = NULL; /* nothing has arrived */;
RECV_BLOCK_IO();
if (full_recvbufs == 0)
{
#ifdef DEBUG
if (debug > 4)
printf("getrecvbufs called, no action here\n");
#endif
}
else {
/*
* Get the fulllist chain and mark it empty
*/
#ifdef DEBUG
if (debug > 4)
printf("getrecvbufs returning %ld buffers\n", full_recvbufs);
#endif
rb = beginlist;
fulllist = 0;
full_recvbufs = 0;
/*
* Check to see if we're below the low water mark.
*/
if (free_recvbufs <= RECV_LOWAT)
{
if (total_recvbufs >= RECV_TOOMANY)
msyslog(LOG_ERR, "too many recvbufs allocated (%ld)",
total_recvbufs);
else
{
create_buffers();
}
}
}
RECV_UNBLOCK_IO();
/*
* Return the chain
*/
return rb;
}
/*
* freerecvbuf - make a single recvbuf available for reuse
*/
void
freerecvbuf(
struct recvbuf *rb
)
{
RECV_BLOCK_IO();
BLOCKIO();
rb->next = (struct recvbuf *) freelist;
freelist = rb;
free_recvbufs++;
UNBLOCKIO();
RECV_UNBLOCK_IO();
}
void
add_full_recv_buffer(
struct recvbuf *rb
)
{
RECV_BLOCK_IO();
if (full_recvbufs == 0)
{
beginlist = rb;
rb->next = 0;
}
else
{
rb->next = fulllist->next;
fulllist->next = rb;
}
fulllist = rb;
full_recvbufs++;
RECV_UNBLOCK_IO();
}
struct recvbuf *
get_free_recv_buffer(void)
{
struct recvbuf * buffer = NULL;
RECV_BLOCK_IO();
if (free_recvbufs <= RECV_LOWAT)
{
if (total_recvbufs >= RECV_TOOMANY) {
msyslog(LOG_ERR, "too many recvbufs allocated (%ld)",
total_recvbufs);
}
else
{
create_buffers();
}
}
if (free_recvbufs > 0)
{
buffer = freelist;
freelist = buffer->next;
buffer->next = NULL;
--free_recvbufs;
}
RECV_UNBLOCK_IO();
return buffer;
}
struct recvbuf *
get_full_recv_buffer(void)
{
struct recvbuf * buffer = NULL;
RECV_BLOCK_IO();
if (full_recvbufs > 0) {
--full_recvbufs;
buffer = beginlist;
beginlist = buffer->next;
buffer->next = NULL;
}
RECV_UNBLOCK_IO();
return buffer;
}