tcpto.c

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#include <sys/socket.h>
#include <unistd.h>
#include "tcpto.h"
#include "open.h"
#include "lock.h"
#include "seek.h"
#include "now.h"
#include "ip.h"
#include "ipalloc.h"
#include "byte.h"
#include "datetime.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);
}