#include "tcpto.h"

#include <sys/socket.h>
#include <unistd.h>

#include "byte.h"
#include "ip.h"
#include "lock.h"
#include "open.h"
#include "seek.h"

#include "datetime.h"
#include "ipalloc.h"
#include "now.h"

char tcpto_buf[1024];

static int flagwasthere;
static int fdlock;

static int getbuf()
{
  int r;
  int fd;

  fdlock = open_write("queue/lock/tcpto");
  if (fdlock == -1) return 0;
  fd = open_read("queue/lock/tcpto");
  if (fd == -1) {
    close(fdlock);
    return 0;
  }
  if (lock_ex(fdlock) == -1) {
    close(fdlock);
    close(fd);
    return 0;
  }
  r = read(fd, tcpto_buf, sizeof(tcpto_buf));
  close(fd);
  if (r < 0) {
    close(fdlock);
    return 0;
  }
  r >>= 5;
  if (!r) close(fdlock);
  return r;
}

int tcpto(struct ip_mx *ix)
{
  int af = ix->af;
  struct ip_address *ip = &ix->addr;
  int n;
  int i;
  char *record;
  datetime_sec when;

  flagwasthere = 0;

  n = getbuf();
  if (!n) return 0;
  close(fdlock);

  record = tcpto_buf;

  for (i = 0; i < n; ++i) {
    if (af == record[0] && byte_equal(ip->d, af == AF_INET ? 4 : 16, record + 16)) {
      flagwasthere = 1;
      if (record[4] >= 2) {
        when = (unsigned long)(unsigned char)record[11];
        when = (when << 8) + (unsigned long)(unsigned char)record[10];
        when = (when << 8) + (unsigned long)(unsigned char)record[9];
        when = (when << 8) + (unsigned long)(unsigned char)record[8];

        if (now() - when < ((60 + (getpid() & 31)) << 6)) return 1;
      }
      return 0;
    }
    record += 32;
  }
  return 0;
}

void tcpto_err(struct ip_mx *ix, int flagerr)
{
  int af = ix->af;
  struct ip_address *ip = &ix->addr;
  int n;
  int i;
  char *record;
  datetime_sec when;
  datetime_sec firstwhen;
  int firstpos;
  datetime_sec lastwhen;

  if (!flagerr)
    if (!flagwasthere) return; /* could have been added, but not worth the effort to check */

  n = getbuf();
  if (!n) return;

  record = tcpto_buf;

  for (i = 0; i < n; ++i) {
    if (af == record[0] && byte_equal(ip->d, af == AF_INET ? 4 : 16, record + 16)) {
      if (!flagerr)
        record[4] = 0;
      else {
        lastwhen = (unsigned long)(unsigned char)record[11];
        lastwhen = (lastwhen << 8) + (unsigned long)(unsigned char)record[10];
        lastwhen = (lastwhen << 8) + (unsigned long)(unsigned char)record[9];
        lastwhen = (lastwhen << 8) + (unsigned long)(unsigned char)record[8];
        when = now();

        if (record[4] && (when < 120 + lastwhen)) {
          close(fdlock);
          return;
        }

        if (++record[4] > 10) record[4] = 10;
        record[8] = when;
        when >>= 8;
        record[9] = when;
        when >>= 8;
        record[10] = when;
        when >>= 8;
        record[11] = when;
      }
      if (seek_set(fdlock, i << 5) == 0)
        if (write(fdlock, record, 32) < 32)
          ; /*XXX*/
      close(fdlock);
      return;
    }
    record += 32;
  }

  if (!flagerr) {
    close(fdlock);
    return;
  }

  record = tcpto_buf;

  for (i = 0; i < n; ++i) {
    if (!record[4]) break;
    record += 32;
  }

  if (i >= n) {
    firstpos = -1;
    record = tcpto_buf;

    for (i = 0; i < n; ++i) {
      when = (unsigned long)(unsigned char)record[11];
      when = (when << 8) + (unsigned long)(unsigned char)record[10];
      when = (when << 8) + (unsigned long)(unsigned char)record[9];
      when = (when << 8) + (unsigned long)(unsigned char)record[8];
      when += (record[4] << 10);
      if ((firstpos < 0) || (when < firstwhen)) {
        firstpos = i;
        firstwhen = when;
      }
      record += 32;
    }
    i = firstpos;
  }

  if (i >= 0) {
    record = tcpto_buf + (i << 5);
    record[0] = af;
    if (af == AF_INET6)
      byte_copy(record + 16, 16, ip->d);
    else {
      byte_copy(record + 16, 4, ip->d);
      byte_copy(record + 20, 12, "............");
    }
    when = now();
    record[8] = when;
    when >>= 8;
    record[9] = when;
    when >>= 8;
    record[10] = when;
    when >>= 8;
    record[11] = when;
    record[4] = 1;
    if (seek_set(fdlock, i << 5) == 0)
      if (write(fdlock, record, 32) < 32)
        ; /*XXX*/
  }

  close(fdlock);
}