/* pdumpq - Pcap Dump for Linux/Netfilter QUEUE
 *
 * Copyright (C) 2001 Ian Jones <roux@speakeasy.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include <app.h>

void
set_signals (void)
{
  v.sa.sa_handler = q_handler;
  sigemptyset (&v.sa.sa_mask);
  sigaddset (&v.sa.sa_mask, SIGTERM);
  sigaddset (&v.sa.sa_mask, SIGHUP);
#ifdef MAIL
  if (v.mail)
    sigaddset (&v.sa.sa_mask, SIGALRM);
#endif /* MAIL */
  v.sa.sa_flags = 0;
  sigaction (SIGTERM, &v.sa, 0);
  sigaction (SIGHUP, &v.sa, 0);
#ifdef MAIL
  if (v.mail)
    sigaction (SIGALRM, &v.sa, 0);
#endif /* MAIL */
}

pid_t
is_running (void)
{
  pid_t pid;
  int err;
  FILE *fp;

  if ((fp = fopen (PIDFILE, "r")) != NULL)
    {
      fscanf (fp, "%d", &pid);
      fclose (fp);
      if (kill (pid, 0) == -1)
	{
	  err = errno;
	  if (err == EPERM)
	    crash ("KILL:pdumpq");
	  /* stale pid, remove it */
	  unlink (PIDFILE);
	  return err == ESRCH ? 0 : -1;
	}
      else
	{
	  /* return pid of running process */
	  return pid;
	}
    }
  else
    {
      if (errno == EACCES)
	crash ("PIDFILE:pdumpq");
      return 0;
    }
}

void
detach (void)
{
  pid_t pid;
  int i;
  FILE *fp;

  if (pid = is_running ())
    {
      fprintf (stderr, "Process [%d] already running, use '-k' to kill.\n",
	       pid);
      exit (1);
    }
  if (pid = fork ())
    {
      if ((fp = fopen (PIDFILE, "w")) == NULL)
	crash ("pdumpq");
      fprintf (fp, "%d", pid);
      fclose (fp);
      exit (0);
    }
  if (pid == -1)
    crash ("fork:pdumpq");
  setsid ();
#ifndef _SC_OPEN_MAX
#define _SC_OPEN_MAX 256
#endif
  for (i = 0; i < (_SC_OPEN_MAX); i++)
    close (i);
  openlog ("pdumpq", LOG_CONS | LOG_PID, LOG_DAEMON);
  syslog (LOG_INFO, "deamon started");
  v.daemon = 2;
}

void
ipq_init (void)
{
  v.h = ipq_create_handle (0);
  if (!v.h || (ipq_set_mode (v.h, IPQ_COPY_PACKET, 0) < 0))
    {
      ipq_perror ("create_handle");
      fprintf (stderr, "Is module ip_queue loaded?");
      ipq_destroy_handle (v.h);
      exit (1);
    }
}

void
process_pkt (ipq_packet_msg_t * m, unsigned int verdict)
{
  if (!dump_pkt (m, v.file))
    crash ("dump_pkt");
#ifdef MAIL
  if (v.mail)
    mail_enqueue (m);
#endif /* MAIL */
  ipq_set_verdict (v.h, m->packet_id, verdict, 0, NULL);
}

int
open_file (char *fn)
{
  int fd;

  if (strcmp (v.dumpfile, "stdout") == 0)
    {
      v.file = stdout;
      return write_file_header (v.file);
    }

  rotate (fn);			/* rotate logs on restart */
  if (
      (fd =
       open (fn, O_WRONLY | O_APPEND | O_CREAT | O_EXCL,
	     S_IRUSR | S_IWUSR)) == -1)
    return -1;
  if ((v.file = fdopen (fd, "a")) == NULL)
    return -1;
  return write_file_header (v.file);
}

/* signal handler */
void
q_handler (int sig)
{
  if (sig == SIGTERM || sig == SIGHUP)
    {
      ipq_destroy_handle (v.h);	/* signal safe? */
      unlink (PIDFILE);
      syslog (LOG_INFO, "deamon killed");
      exit (0);
    }
#ifdef MAIL
  if (v.mail && sig == SIGALRM && queue->num > 0)
    queue->flush = 1;
#endif /*MAIL */
}


void
crash (char *error)
{
  if (v.daemon != 2)
    perror (error);
  else
    syslog (LOG_INFO, "EXITING! %s: %s", error,
	    errno > sys_nerr - 1 ? "Unknown Error" : sys_errlist[errno]);
  exit (1);
}

/* rotate dump files using an incrementing suffix */
void
rotate (char *fn)
{
  int stack;
  char *name, *old;

  if (access (fn, R_OK) == -1)
    {
      if (errno == ENOENT)
	return;
      else
	crash ("rotating dumpfile:pdumpq");
    }
  if (v.rotate == 0)
    {
      if (unlink (fn) == -1 && errno == EACCES)
	crash ("unable to clobber:pdumpq");
      return;
    }

  stack = 0;
  while (1)
    {				/* note: stack autoincrement */
      asprintf (&name, "%s.%d", fn, ++stack);
      if (access (name, R_OK) == -1)
	{
	  if (errno != ENOENT)
	    crash ("rotating dumpfile:pdumpq");
	  while (stack)
	    {
	      if (stack == 1)
		{
		  rename (fn, name);
		  free (name);
		  name = fn;
		  stack--;
		}
	      else
		{
		  asprintf (&old, "%s.%d", fn, --stack);
		  if (stack + 1 == v.rotate)
		    {
		      unlink (old);
		    }
		  else if (stack < v.rotate)
		    rename (old, name);
		  free (name);
		  name = old;
		}
	    }
	  break;
	}
      free (name);
    }
}

int
gmt2local (time_t t)		/* ripped from snort, from tcpdump */
{
  register int dt, dir;
  register struct tm *gmt, *loc;
  struct tm sgmt;
  if (t == 0)
    t = time (NULL);
  gmt = &sgmt;
  *gmt = *gmtime (&t);
  loc = localtime (&t);
  dt = (loc->tm_hour - gmt->tm_hour) * 60 * 60 +
    (loc->tm_min - gmt->tm_min) * 60;
  dir = loc->tm_year - gmt->tm_year;
  if (dir == 0)
    dir = loc->tm_yday - gmt->tm_yday;
  dt += dir * 24 * 60 * 60;
  return (dt);
}