/*	$OpenBSD: isakmpd.c,v 1.57 2004/02/19 15:35:16 hshoexer Exp $	*/
/*	$EOM: isakmpd.c,v 1.54 2000/10/05 09:28:22 niklas Exp $	*/

/*
 * Copyright (c) 1998, 1999, 2000, 2001 Niklas Hallqvist.  All rights reserved.
 * Copyright (c) 1999, 2000 Angelos D. Keromytis.  All rights reserved.
 * Copyright (c) 1999, 2000, 2001 Håkan Olsson.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This code was written under funding by Ericsson Radio Systems.
 */

#include <errno.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>

#include "sysdep.h"

#include "app.h"
#include "conf.h"
#include "connection.h"
#include "init.h"
#include "libcrypto.h"
#include "log.h"
#include "monitor.h"
#include "sa.h"
#include "timer.h"
#include "transport.h"
#include "udp.h"
#include "ui.h"
#include "util.h"
#include "cert.h"

#ifdef USE_POLICY
#include "policy.h"
#endif

static void usage (void);

/*
 * Set if -d is given, currently just for running in the foreground and log
 * to stderr instead of syslog.
 */
int debug = 0;

/*
 * If we receive a SIGHUP signal, this flag gets set to show we need to
 * reconfigure ASAP.
 */
volatile sig_atomic_t sighupped = 0;

/*
 * If we receive a USR1 signal, this flag gets set to show we need to dump
 * a report over our internal state ASAP.  The file to report to is settable
 * via the -R parameter.
 */
volatile sig_atomic_t sigusr1ed = 0;
static char *report_file = "/var/run/isakmpd.report";

/*
 * If we receive a USR2 signal, this flag gets set to show we need to
 * rehash our SA soft expiration timers to a uniform distribution.
 * XXX Perhaps this is a really bad idea?
 */
volatile sig_atomic_t sigusr2ed = 0;

/*
 * If we receive a TERM signal, perform a "clean shutdown" of the daemon.
 * This includes to send DELETE notifications for all our active SAs.
 * Also on recv of an INT signal (Ctrl-C out of an '-d' session, typically).
 */
volatile sig_atomic_t sigtermed = 0;
void daemon_shutdown_now (int);

/* The default path of the PID file.  */
static char *pid_file = "/var/run/isakmpd.pid";

#ifdef USE_DEBUG
/* The path of the IKE packet capture log file.  */
static char *pcap_file = 0;
#endif

static void
usage (void)
{
  fprintf (stderr,
	   "usage: %s [-4] [-6] [-c config-file] [-d] [-D class=level]\n"
	   "          [-f fifo] [-i pid-file] [-n] [-p listen-port]\n"
	   "          [-P local-port] [-L] [-l packetlog-file] [-r seed]\n"
	   "          [-R report-file] [-v]\n",
	   sysdep_progname ());
  exit (1);
}

static void
parse_args (int argc, char *argv[])
{
  int ch;
  char *ep;
#ifdef USE_DEBUG
  int cls, level;
  int do_packetlog = 0;
#endif

  while ((ch = getopt (argc, argv, "46c:dD:f:i:np:P:Ll:r:R:v")) != -1) {
    switch (ch) {
    case '4':
      bind_family |= BIND_FAMILY_INET4;
      break;

    case '6':
      bind_family |= BIND_FAMILY_INET6;
      break;

    case 'c':
      conf_path = optarg;
      break;

    case 'd':
      debug++;
      break;

#ifdef USE_DEBUG
    case 'D':
      if (sscanf (optarg, "%d=%d", &cls, &level) != 2)
	{
	    if (sscanf (optarg, "A=%d", &level) == 1)
	      {
		  for (cls = 0; cls < LOG_ENDCLASS; cls++)
		    log_debug_cmd (cls, level);
	      }
	    else
	      log_print ("parse_args: -D argument unparseable: %s", optarg);
	}
      else
	log_debug_cmd (cls, level);
      break;
#endif /* USE_DEBUG */

    case 'f':
      ui_fifo = optarg;
      break;

    case 'i':
      pid_file = optarg;
      break;

    case 'n':
      app_none++;
      break;

    case 'p':
      udp_default_port = optarg;
      break;

    case 'P':
      udp_bind_port = optarg;
      break;

#ifdef USE_DEBUG
    case 'l':
      pcap_file = optarg;
      /* Fallthrough intended.  */

    case 'L':
      do_packetlog++;
      break;
#endif /* USE_DEBUG */

    case 'r':
      seed = strtoul (optarg, &ep, 0);
      srandom (seed);
      if (*ep != '\0')
	log_fatal ("parse_args: invalid numeric arg to -r (%s)", optarg);
      regrand = 1;
      break;

    case 'R':
      report_file = optarg;
      break;

    case 'v':
      verbose_logging = 1;
      break;

    case '?':
    default:
      usage ();
    }
  }
  argc -= optind;
  argv += optind;

#ifdef USE_DEBUG
  if (do_packetlog && !pcap_file)
    pcap_file = PCAP_FILE_DEFAULT;
#endif
}

static void
sighup (int sig)
{
  sighupped = 1;
}

/* Report internal state on SIGUSR1.  */
static void
report (void)
{
  FILE *rfp, *old;
  mode_t old_umask;

  old_umask = umask (S_IRWXG | S_IRWXO);
  rfp = monitor_fopen (report_file, "w");
  umask (old_umask);

  if (!rfp)
    {
      log_error ("report: fopen (\"%s\", \"w\") failed", report_file);
      return;
    }

  /* Divert the log channel to the report file during the report.  */
  old = log_current ();
  log_to (rfp);
  ui_report ("r");
  log_to (old);
  fclose (rfp);

  sigusr1ed = 0;
}

static void
sigusr1 (int sig)
{
  sigusr1ed = 1;
}

/* Rehash soft expiration timers on SIGUSR2.  */
static void
rehash_timers (void)
{
#if 0
  /* XXX - not yet */
  log_print ("SIGUSR2 received, rehashing soft expiration timers.");

  timer_rehash_timers ();
#endif

  sigusr2ed = 0;
}

static void
sigusr2 (int sig)
{
  sigusr2ed = 1;
}

static int
phase2_sa_check (struct sa *sa, void *arg)
{
  return sa->phase == 2;
}

static void
daemon_shutdown (void)
{
  /* Perform a (protocol-wise) clean shutdown of the daemon.  */
  struct sa *sa;

  if (sigtermed == 1)
    {
      log_print ("isakmpd: shutting down...");

      /* Delete all active phase 2 SAs.  */
      while ((sa = sa_find (phase2_sa_check, NULL)))
	{
	  /* Each DELETE is another (outgoing) message.  */
	  sa_delete (sa, 1);
	}
      sigtermed++;
    }

  if (transport_prio_sendqs_empty ())
    {
      /*
       * When the prioritized transport sendq:s are empty, i.e all
       * the DELETE notifications have been sent, we can shutdown.
       */
	
#ifdef USE_DEBUG
      log_packet_stop ();
#endif
      /* Remove FIFO and pid files.  */
      unlink (ui_fifo);
      unlink (pid_file);
      log_print ("isakmpd: exit");
      exit (0);
    }
}

/* Called on SIGTERM, SIGINT or by ui_shutdown_daemon().  */
void
daemon_shutdown_now (int sig)
{
  sigtermed = 1;
}

/* Write pid file.  */
static void
write_pid_file (void)
{
  FILE *fp;

  /* Ignore errors. This will fail with USE_PRIVSEP.  */
  unlink (pid_file);

  fp = monitor_fopen (pid_file, "w");
  if (fp != NULL)
    {
      if (fprintf (fp, "%ld\n", (long) getpid ()) < 0)
	log_error ("write_pid_file: failed to write PID to \"%.100s\"",
	           pid_file);
      fclose (fp);
    }
  else
    log_fatal ("write_pid_file: fopen (\"%.100s\", \"w\") failed", pid_file);
}

int
main (int argc, char *argv[])
{
  fd_set *rfds, *wfds;
  int n, m;
  size_t mask_size;
  struct timeval tv, *timeout;

  /* Make sure init() won't alloc fd 0, 1 or 2, as daemon() will close them. */
  for (n = 0; n <= 2; n++)
    if (fcntl (n, F_GETFL, 0) == -1 && errno == EBADF)
      (void)open ("/dev/null", n ? O_WRONLY : O_RDONLY, 0);

  /* Log cmd line parsing and initialization errors to stderr.  */
  log_to (stderr);
  parse_args (argc, argv);
  log_init (debug);

  /*
   * Do a clean daemon shutdown on TERM/INT. These signals must be
   * initialized before monitor_init(). INT is only used with '-d'.
   */
  signal (SIGTERM, daemon_shutdown_now);
  if (debug == 1) /* i.e '-dd' will skip this.  */
    signal (SIGINT, daemon_shutdown_now);

#if defined (USE_PRIVSEP)
  if (monitor_init ())
    {
      /* The parent, with privileges.  */
      if (!debug)
	if (daemon (0, 0))
	  log_fatal ("main [priv]: daemon (0, 0) failed");

      /* Enter infinite monitor loop.  */
      monitor_loop (debug);
      exit (0); /* Never reached.  */
    }

  /* Child process only from this point on, no privileges left.  */
#endif

  init ();

  if (!debug)
    if (daemon (0, 0))
      log_fatal ("main: daemon (0, 0) failed");

  write_pid_file ();

  /* Reinitialize on HUP reception.  */
  signal (SIGHUP, sighup);

  /* Report state on USR1 reception.  */
  signal (SIGUSR1, sigusr1);

  /* Rehash soft expiration timers on USR2 reception.  */
  signal (SIGUSR2, sigusr2);

#if defined (USE_DEBUG)
  /* If we wanted IKE packet capture to file, initialize it now.  */
  if (pcap_file != 0)
    log_packet_init (pcap_file);
#endif

  /* Allocate the file descriptor sets just big enough.  */
  n = getdtablesize ();
  mask_size = howmany (n, NFDBITS) * sizeof (fd_mask);
  rfds = (fd_set *)malloc (mask_size);
  if (!rfds)
    log_fatal ("main: malloc (%lu) failed", (unsigned long)mask_size);
  wfds = (fd_set *)malloc (mask_size);
  if (!wfds)
    log_fatal ("main: malloc (%lu) failed", (unsigned long)mask_size);

  while (1)
    {
      /* If someone has sent SIGHUP to us, reconfigure.  */
      if (sighupped)
	{
	  log_print ("SIGHUP received");
	  reinit ();
	  sighupped = 0;
	}

      /* and if someone sent SIGUSR1, do a state report.  */
      if (sigusr1ed)
	{
	  log_print ("SIGUSR1 received");
	  report ();
	}

      /* and if someone sent SIGUSR2, do a timer rehash.  */
      if (sigusr2ed)
	{
	  log_print ("SIGUSR2 received");
	  rehash_timers ();
	}

      /*
       * and if someone set 'sigtermed' (SIGTERM, SIGINT or via the UI),
       * this indicates we should start a controlled shutdown of the daemon.
       *
       * Note: Since _one_ message is sent per iteration of this enclosing
       * while-loop, and we want to send a number of DELETE notifications,
       * we must loop atleast this number of times. The daemon_shutdown()
       * function starts by queueing the DELETEs, all other calls just
       * increments the 'sigtermed' variable until it reaches a "safe"
       * value, and the daemon exits.
       */
      if (sigtermed)
	daemon_shutdown ();

      /* Setup the descriptors to look for incoming messages at.  */
      memset (rfds, 0, mask_size);
      n = transport_fd_set (rfds);
      FD_SET (ui_socket, rfds);
      if (ui_socket + 1 > n)
	n = ui_socket + 1;

      /*
       * XXX Some day we might want to deal with an abstract application
       * class instead, with many instantiations possible.
       */
      if (!app_none && app_socket >= 0)
	{
	  FD_SET (app_socket, rfds);
	  if (app_socket + 1 > n)
	    n = app_socket + 1;
	}

      /* Setup the descriptors that have pending messages to send.  */
      memset (wfds, 0, mask_size);
      m = transport_pending_wfd_set (wfds);
      if (m > n)
	n = m;

      /* Find out when the next timed event is.  */
      timeout = &tv;
      timer_next_event (&timeout);

      n = select (n, rfds, wfds, 0, timeout);
      if (n == -1)
	{
	  if (errno != EINTR)
	    {
	      log_error ("main: select");

	      /*
	       * In order to give the unexpected error condition time to
	       * resolve without letting this process eat up all available CPU
	       * we sleep for a short while.
	       */
	      sleep (1);
	    }
	}
      else if (n)
	{
	  transport_handle_messages (rfds);
	  transport_send_messages (wfds);
	  if (FD_ISSET (ui_socket, rfds))
	    ui_handler ();
	  if (!app_none && app_socket >= 0 && FD_ISSET (app_socket, rfds))
	    app_handler ();
	}
      timer_handle_expirations ();
    }
}