#ifdef HAVE_CONFIG_H

# include <config.h>

#endif

#include <stdio.h>

#include "ntp_assert.h"

#include "ntp_syslog.h"

#include "ntp_stdlib.h"

#include "ntp_lists.h"

#include "recvbuff.h"

#include "iosignal.h"

/*

 * Memory allocation

 */

static u_long volatile full_recvbufs; /* recvbufs on full_recv_fifo */

static u_long volatile free_recvbufs; /* recvbufs on free_recv_list */

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 u_long volatile buffer_shortfall;/* number of missed free receive buffers

             between replenishments */

static DECL_FIFO_ANCHOR(recvbuf_t) full_recv_fifo;

static recvbuf_t *       free_recv_list;

#if defined(SYS_WINNT)

/*

 * For Windows we need to set up a lock to manipulate the

 * recv buffers to prevent corruption. We keep it lock for as

 * short a time as possible

 */

static CRITICAL_SECTION RecvLock;

# define LOCK()   EnterCriticalSection(&RecvLock)

# define UNLOCK() LeaveCriticalSection(&RecvLock)

#else

# define LOCK()   do {} while (FALSE)

# define UNLOCK() do {} while (FALSE)

#endif

#ifdef DEBUG

static void uninit_recvbuff(void);

#endif

u_long

free_recvbuffs (void)

{

  return free_recvbufs;

}

u_long

full_recvbuffs (void)

{

  return full_recvbufs;

}

u_long

total_recvbuffs (void)

{

  return total_recvbufs;

}

u_long

lowater_additions(void)

{

  return lowater_adds;

}

static inline void 

initialise_buffer(recvbuf_t *buff)

{

  ZERO(*buff);

}

static void

create_buffers(int nbufs)

{

  register recvbuf_t *bufp;

  int i, abuf;

  abuf = nbufs + buffer_shortfall;

  buffer_shortfall = 0;

#ifndef DEBUG

  bufp = eallocarray(abuf, sizeof(*bufp));

#endif

  for (i = 0; i < abuf; i++) {

#ifdef DEBUG

    /*

     * Allocate each buffer individually so they can be

     * free()d during ntpd shutdown on DEBUG builds to

     * keep them out of heap leak reports.

     */

    bufp = emalloc_zero(sizeof(*bufp));

#endif

    LINK_SLIST(free_recv_list, bufp, link);

    bufp++;

    free_recvbufs++;

    total_recvbufs++;

  }

  lowater_adds++;

}

void

init_recvbuff(int nbufs)

{

  /*

   * Init buffer free list and stat counters

   */

  free_recvbufs = total_recvbufs = 0;

  full_recvbufs = lowater_adds = 0;

  create_buffers(nbufs);

#if defined(SYS_WINNT)

  InitializeCriticalSection(&RecvLock);

#endif

#ifdef DEBUG

  atexit(&uninit_recvbuff);

#endif

}

#ifdef DEBUG

static void

uninit_recvbuff(void)

{

  recvbuf_t *rbunlinked;

  for (;;) {

    UNLINK_FIFO(rbunlinked, full_recv_fifo, link);

    if (rbunlinked == NULL)

      break;

    free(rbunlinked);

  }

  for (;;) {

    UNLINK_HEAD_SLIST(rbunlinked, free_recv_list, link);

    if (rbunlinked == NULL)

      break;

    free(rbunlinked);

  }

}

#endif  /* DEBUG */

/*

 * freerecvbuf - make a single recvbuf available for reuse

 */

void

freerecvbuf(recvbuf_t *rb)

{

  if (rb) {

    LOCK();

    rb->used--;

    if (rb->used != 0)

      msyslog(LOG_ERR, "******** freerecvbuff non-zero usage: %d *******", rb->used);

    LINK_SLIST(free_recv_list, rb, link);

    free_recvbufs++;

    UNLOCK();

  }

}

void

add_full_recv_buffer(recvbuf_t *rb)

{

  if (rb == NULL) {

    msyslog(LOG_ERR, "add_full_recv_buffer received NULL buffer");

    return;

  }

  LOCK();

  LINK_FIFO(full_recv_fifo, rb, link);

  full_recvbufs++;

  UNLOCK();

}

recvbuf_t *

get_free_recv_buffer(void)

{

  recvbuf_t *buffer;

  LOCK();

  UNLINK_HEAD_SLIST(buffer, free_recv_list, link);

  if (buffer != NULL) {

    free_recvbufs--;

    initialise_buffer(buffer);

    buffer->used++;

  } else {

    buffer_shortfall++;

  }

  UNLOCK();

  return buffer;

}

#ifdef HAVE_IO_COMPLETION_PORT

recvbuf_t *

get_free_recv_buffer_alloc(void)

{

  recvbuf_t *buffer;

  buffer = get_free_recv_buffer();

  if (NULL == buffer) {

    create_buffers(RECV_INC);

    buffer = get_free_recv_buffer();

  }

  ENSURE(buffer != NULL);

  return (buffer);

}

#endif

recvbuf_t *

get_full_recv_buffer(void)

{

  recvbuf_t * rbuf;

  LOCK();

#ifdef HAVE_SIGNALED_IO

  /*

   * make sure there are free buffers when we

   * wander off to do lengthy packet processing with

   * any buffer we grab from the full list.

   * 

   * fixes malloc() interrupted by SIGIO risk

   * (Bug 889)

   */

  if (NULL == free_recv_list || buffer_shortfall > 0) {

    /*

     * try to get us some more buffers

     */

    create_buffers(RECV_INC);

  }

#endif

  /*

   * try to grab a full buffer

   */

  UNLINK_FIFO(rbuf, full_recv_fifo, link);

  if (rbuf != NULL)

    full_recvbufs--;

  UNLOCK();

  return rbuf;

}

/*

 * purge_recv_buffers_for_fd() - purges any previously-received input

 *         from a given file descriptor.

 */

void

purge_recv_buffers_for_fd(

  int fd

  )

{

  recvbuf_t *rbufp;

  recvbuf_t *next;

  recvbuf_t *punlinked;

  LOCK();

  for (rbufp = HEAD_FIFO(full_recv_fifo);

       rbufp != NULL;

       rbufp = next) {

    next = rbufp->link;

#     ifdef HAVE_IO_COMPLETION_PORT

    if (rbufp->dstadr == NULL && rbufp->fd == fd)

#     else

    if (rbufp->fd == fd)

#     endif

    {

      UNLINK_MID_FIFO(punlinked, full_recv_fifo,

          rbufp, link, recvbuf_t);

      INSIST(punlinked == rbufp);

      full_recvbufs--;

      freerecvbuf(rbufp);

    }

  }

  UNLOCK();

}

/*

 * Checks to see if there are buffers to process

 */

isc_boolean_t has_full_recv_buffer(void)

{

  if (HEAD_FIFO(full_recv_fifo) != NULL)

    return (ISC_TRUE);

  else

    return (ISC_FALSE);

}

#ifdef NTP_DEBUG_LISTS_H

void

check_gen_fifo_consistency(void *fifo)

{

  gen_fifo *pf;

  gen_node *pthis;

  gen_node **pptail;

  pf = fifo;

  REQUIRE((NULL == pf->phead && NULL == pf->pptail) ||

    (NULL != pf->phead && NULL != pf->pptail));

  pptail = &pf->phead;

  for (pthis = pf->phead;

       pthis != NULL;

       pthis = pthis->link)

    if (NULL != pthis->link)

      pptail = &pthis->link;

  REQUIRE(NULL == pf->pptail || pptail == pf->pptail);

}

#endif  /* NTP_DEBUG_LISTS_H */