/* strongSwan IPsec starter
 * Copyright (C) 2001-2002 Mathieu Lafon - Arkoon Network Security
 *
 * 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.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * 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.
 */

#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <unistd.h>
#include <sys/time.h>
#include <time.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <grp.h>

#include <freeswan.h>
#include <library.h>

#include "../pluto/constants.h"
#include "../pluto/defs.h"
#include "../pluto/log.h"

#include "confread.h"
#include "files.h"
#include "starterwhack.h"
#include "starterstroke.h"
#include "invokepluto.h"
#include "invokecharon.h"
#include "netkey.h"
#include "klips.h"
#include "cmp.h"
#include "interfaces.h"

/**
 * Return codes defined by Linux Standard Base Core Specification 3.1
 * in section 20.2. Init Script Actions
 */
#define LSB_RC_SUCCESS               0   /* success                          */
#define LSB_RC_FAILURE               1   /* generic or unspecified error     */
#define LSB_RC_INVALID_ARGUMENT      2   /* invalid or excess argument(s)    */
#define LSB_RC_NOT_IMPLEMENTED       3   /* unimplemented feature (reload)   */
#define LSB_RC_NOT_ALLOWED           4   /* user had insufficient privilege  */
#define LSB_RC_NOT_INSTALLED         5   /* program is not installed         */
#define LSB_RC_NOT_CONFIGURED        6   /* program is not configured        */
#define LSB_RC_NOT_RUNNING           7   /* program is not running           */

#define FLAG_ACTION_START_PLUTO   0x01
#define FLAG_ACTION_UPDATE        0x02
#define FLAG_ACTION_RELOAD        0x04
#define FLAG_ACTION_QUIT          0x08
#define FLAG_ACTION_LISTEN        0x10
#define FLAG_ACTION_START_CHARON  0x20

static unsigned int _action_ = 0;

static void fsig(int signal)
{
	switch (signal)
	{
		case SIGCHLD:
		{
			int status, exit_status = 0;
			pid_t pid;
			char *name = NULL;

			while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
			{
				if (pid == starter_pluto_pid())
				{
					name = " (Pluto)";
				}
				if (pid == starter_charon_pid())
				{
					name = " (Charon)";
				}
				if (WIFSIGNALED(status))
				{
					DBG(DBG_CONTROL,
						DBG_log("child %d%s has been killed by sig %d\n",
								pid, name?name:"", WTERMSIG(status))
					   )
				}
				else if (WIFSTOPPED(status))
				{
					DBG(DBG_CONTROL,
						DBG_log("child %d%s has been stopped by sig %d\n",
								pid, name?name:"", WSTOPSIG(status))
					   )
				}
				else if (WIFEXITED(status))
				{
					exit_status =  WEXITSTATUS(status);
					if (exit_status >= SS_RC_FIRST && exit_status <= SS_RC_LAST)
					{
						_action_ =  FLAG_ACTION_QUIT;
					}
					DBG(DBG_CONTROL,
						DBG_log("child %d%s has quit (exit code %d)\n",
								pid, name?name:"", exit_status)
					   )
				}
				else
				{
					DBG(DBG_CONTROL,
						DBG_log("child %d%s has quit", pid, name?name:"")
					   )
				}
				if (pid == starter_pluto_pid())
				{
					starter_pluto_sigchild(pid, exit_status);
				}
				if (pid == starter_charon_pid())
				{
					starter_charon_sigchild(pid, exit_status);
				}
			}
		}
		break;

		case SIGPIPE:
			/** ignore **/
			break;

		case SIGALRM:
			_action_ |= FLAG_ACTION_START_PLUTO;
			_action_ |= FLAG_ACTION_START_CHARON;
			break;

		case SIGHUP:
			_action_ |= FLAG_ACTION_UPDATE;
			break;

		case SIGTERM:
		case SIGQUIT:
		case SIGINT:
			_action_ |= FLAG_ACTION_QUIT;
			break;

		case SIGUSR1:
			_action_ |= FLAG_ACTION_RELOAD;
			_action_ |= FLAG_ACTION_UPDATE;
			break;

		default:
			plog("fsig(): unknown signal %d -- investigate", signal);
			break;
	}
}

static void generate_selfcert()
{
	struct stat stb;

		/* if ipsec.secrets file is missing then generate RSA default key pair */
		if (stat(SECRETS_FILE, &stb) != 0)
		{
			mode_t oldmask;
			FILE *f;
			uid_t uid = 0;
			gid_t gid = 0;

#ifdef IPSEC_GROUP
			{
				char buf[1024];
				struct group group, *grp;

				if (getgrnam_r(IPSEC_GROUP, &group, buf, sizeof(buf), &grp) == 0 &&	grp)
				{
					gid = grp->gr_gid;
				}
			}
#endif
#ifdef IPSEC_USER
			{
				char buf[1024];
				struct passwd passwd, *pwp;

				if (getpwnam_r(IPSEC_USER, &passwd, buf, sizeof(buf), &pwp) == 0 &&	pwp)
				{
					uid = pwp->pw_uid;
				}
			}
#endif
			setegid(gid);
			seteuid(uid);
			ignore_result(system("ipsec scepclient --out pkcs1 --out cert-self --quiet"));
			seteuid(0);
			setegid(0);

			/* ipsec.secrets is root readable only */
			oldmask = umask(0066);

			f = fopen(SECRETS_FILE, "w");
			if (f)
			{
				fprintf(f, "# /etc/ipsec.secrets - strongSwan IPsec secrets file\n");
				fprintf(f, "\n");
				fprintf(f, ": RSA myKey.der\n");
				fclose(f);
			}
			ignore_result(chown(SECRETS_FILE, uid, gid));
			umask(oldmask);
		}
}

static void usage(char *name)
{
	fprintf(stderr, "Usage: starter [--nofork] [--auto-update <sec>] "
			"[--debug|--debug-more|--debug-all]\n");
	exit(LSB_RC_INVALID_ARGUMENT);
}

int main (int argc, char **argv)
{
	starter_config_t *cfg = NULL;
	starter_config_t *new_cfg;
	starter_conn_t *conn, *conn2;
	starter_ca_t *ca, *ca2;

	struct stat stb;

	char *err = NULL;
	int i;
	int id = 1;
	struct timeval tv;
	unsigned long auto_update = 0;
	time_t last_reload;
	bool no_fork = FALSE;
	bool attach_gdb = FALSE;

	/* global variables defined in log.h */
	log_to_stderr = TRUE;
	base_debugging = DBG_NONE;

	library_init(NULL);
	atexit(library_deinit);

	/* parse command line */
	for (i = 1; i < argc; i++)
	{
		if (streq(argv[i], "--debug"))
		{
			base_debugging |= DBG_CONTROL;
		}
		else if (streq(argv[i], "--debug-more"))
		{
			base_debugging |= DBG_CONTROLMORE;
		}
		else if (streq(argv[i], "--debug-all"))
		{
			base_debugging |= DBG_ALL;
		}
		else if (streq(argv[i], "--nofork"))
		{
			no_fork = TRUE;
		}
		else if (streq(argv[i], "--attach-gdb"))
		{
			no_fork = TRUE;
			attach_gdb = TRUE;
		}
		else if (streq(argv[i], "--auto-update") && i+1 < argc)
		{
			auto_update = atoi(argv[++i]);
			if (!auto_update)
				usage(argv[0]);
		}
		else
		{
			usage(argv[0]);
		}
	}

	/* Init */
	init_log("ipsec_starter");
	cur_debugging = base_debugging;

	signal(SIGHUP,  fsig);
	signal(SIGCHLD, fsig);
	signal(SIGPIPE, fsig);
	signal(SIGINT,  fsig);
	signal(SIGTERM, fsig);
	signal(SIGQUIT, fsig);
	signal(SIGALRM, fsig);
	signal(SIGUSR1, fsig);

	plog("Starting strongSwan "VERSION" IPsec [starter]...");

	/* verify that we can start */
	if (getuid() != 0)
	{
		plog("permission denied (must be superuser)");
		exit(LSB_RC_NOT_ALLOWED);
	}

	if (stat(PLUTO_PID_FILE, &stb) == 0)
	{
		plog("pluto is already running (%s exists) -- skipping pluto start", PLUTO_PID_FILE);
	}
	else
	{
		_action_ |= FLAG_ACTION_START_PLUTO;
	}
	if (stat(CHARON_PID_FILE, &stb) == 0)
	{
		plog("charon is already running (%s exists) -- skipping charon start", CHARON_PID_FILE);
	}
	else
	{
		_action_ |= FLAG_ACTION_START_CHARON;
	}
	if (stat(DEV_RANDOM, &stb) != 0)
	{
		plog("unable to start strongSwan IPsec -- no %s!", DEV_RANDOM);
		exit(LSB_RC_FAILURE);
	}

	if (stat(DEV_URANDOM, &stb)!= 0)
	{
		plog("unable to start strongSwan IPsec -- no %s!", DEV_URANDOM);
		exit(LSB_RC_FAILURE);
	}

	cfg = confread_load(CONFIG_FILE);
	if (cfg == NULL || cfg->err > 0)
	{
		plog("unable to start strongSwan -- fatal errors in config");
		if (cfg)
		{
			confread_free(cfg);
		}
		exit(LSB_RC_INVALID_ARGUMENT);
	}

	/* determine if we have a native netkey IPsec stack */
	if (!starter_netkey_init())
	{
		plog("no netkey IPsec stack detected");
		if (!starter_klips_init())
		{
			plog("no KLIPS IPsec stack detected");
			plog("no known IPsec stack detected, ignoring!");
		}
	}

	last_reload = time_monotonic(NULL);

	if (stat(STARTER_PID_FILE, &stb) == 0)
	{
		plog("starter is already running (%s exists) -- no fork done", STARTER_PID_FILE);
		confread_free(cfg);
		exit(LSB_RC_SUCCESS);
	}

	generate_selfcert();

	/* fork if we're not debugging stuff */
	if (!no_fork)
	{
		log_to_stderr = FALSE;

		switch (fork())
		{
			case 0:
			{
				int fnull = open("/dev/null", O_RDWR);

				if (fnull >= 0)
				{
					dup2(fnull, STDIN_FILENO);
					dup2(fnull, STDOUT_FILENO);
					dup2(fnull, STDERR_FILENO);
					close(fnull);
				}
				setsid();
			}
			break;
			case -1:
				plog("can't fork: %s", strerror(errno));
				break;
			default:
				confread_free(cfg);
				exit(LSB_RC_SUCCESS);
		}
	}

	/* save pid file in /var/run/starter.pid */
	{
		FILE *fd = fopen(STARTER_PID_FILE, "w");

		if (fd)
		{
			fprintf(fd, "%u\n", getpid());
			fclose(fd);
		}
	}

	for (;;)
	{
		/*
		 * Stop pluto/charon (if started) and exit
		 */
		if (_action_ & FLAG_ACTION_QUIT)
		{
			if (starter_pluto_pid())
			{
				starter_stop_pluto();
			}
			if (starter_charon_pid())
			{
				starter_stop_charon();
			}
			starter_netkey_cleanup();
			confread_free(cfg);
			unlink(STARTER_PID_FILE);
			unlink(INFO_FILE);
			plog("ipsec starter stopped");
			close_log();
			exit(LSB_RC_SUCCESS);
		}

		/*
		 * Delete all connections. Will be added below
		 */
		if (_action_ & FLAG_ACTION_RELOAD)
		{
			if (starter_pluto_pid() || starter_charon_pid())
			{
				for (conn = cfg->conn_first; conn; conn = conn->next)
				{
					if (conn->state == STATE_ADDED)
					{
						if (starter_charon_pid())
						{
							starter_stroke_del_conn(conn);
						}
						if (starter_pluto_pid())
						{
							starter_whack_del_conn(conn);
						}
						conn->state = STATE_TO_ADD;
					}
				}
				for (ca = cfg->ca_first; ca; ca = ca->next)
				{
					if (ca->state == STATE_ADDED)
					{
						if (starter_charon_pid())
						{
							starter_stroke_del_ca(ca);
						}
						if (starter_pluto_pid())
						{
							starter_whack_del_ca(ca);
						}
						ca->state = STATE_TO_ADD;
					}
				}
			}
			_action_ &= ~FLAG_ACTION_RELOAD;
		}

		/*
		 * Update configuration
		 */
		if (_action_ & FLAG_ACTION_UPDATE)
		{
			err = NULL;
			DBG(DBG_CONTROL,
				DBG_log("Reloading config...")
			   );
			new_cfg = confread_load(CONFIG_FILE);

			if (new_cfg && (new_cfg->err + new_cfg->non_fatal_err == 0))
			{
				/* Switch to new config. New conn will be loaded below */
				if (!starter_cmp_defaultroute(&new_cfg->defaultroute
								   , &cfg->defaultroute))
				{
					_action_ |= FLAG_ACTION_LISTEN;
				}

				if (!starter_cmp_pluto(cfg, new_cfg))
				{
					plog("Pluto has changed");
					if (starter_pluto_pid())
						starter_stop_pluto();
					_action_ &= ~FLAG_ACTION_LISTEN;
					_action_ |= FLAG_ACTION_START_PLUTO;
				}
				else
				{
					/* Only reload conn and ca sections if pluto is not killed */

					/* Look for new connections that are already loaded */
					for (conn = cfg->conn_first; conn; conn = conn->next)
					{
						if (conn->state == STATE_ADDED)
						{
							for (conn2 = new_cfg->conn_first; conn2; conn2 = conn2->next)
							{
								if (conn2->state == STATE_TO_ADD && starter_cmp_conn(conn, conn2))
								{
									conn->state = STATE_REPLACED;
									conn2->state = STATE_ADDED;
									conn2->id = conn->id;
									break;
								}
							}
						}
					}

					/* Remove conn sections that have become unused */
					for (conn = cfg->conn_first; conn; conn = conn->next)
					{
						if (conn->state == STATE_ADDED)
						{
							if (starter_charon_pid())
							{
								starter_stroke_del_conn(conn);
							}
							if (starter_pluto_pid())
							{
								starter_whack_del_conn(conn);
							}
						}
					}

					/* Look for new ca sections that are already loaded */
					for (ca = cfg->ca_first; ca; ca = ca->next)
					{
						if (ca->state == STATE_ADDED)
						{
							for (ca2 = new_cfg->ca_first; ca2; ca2 = ca2->next)
							{
								if (ca2->state == STATE_TO_ADD && starter_cmp_ca(ca, ca2))
								{
									ca->state = STATE_REPLACED;
									ca2->state = STATE_ADDED;
									break;
								}
							}
						}
					}

					/* Remove ca sections that have become unused */
					for (ca = cfg->ca_first; ca; ca = ca->next)
					{
						if (ca->state == STATE_ADDED)
						{
							if (starter_charon_pid())
							{
								starter_stroke_del_ca(ca);
							}
							if (starter_pluto_pid())
							{
								starter_whack_del_ca(ca);
							}
						}
					}
				}
				confread_free(cfg);
				cfg = new_cfg;
			}
			else
			{
				plog("can't reload config file due to errors -- keeping old one");
				if (new_cfg)
				{
					confread_free(new_cfg);
				}
			}
			_action_ &= ~FLAG_ACTION_UPDATE;
			last_reload = time_monotonic(NULL);
		}

		/*
		 * Start pluto
		 */
		if (_action_ & FLAG_ACTION_START_PLUTO)
		{
			if (cfg->setup.plutostart && !starter_pluto_pid())
			{
				DBG(DBG_CONTROL,
					DBG_log("Attempting to start pluto...")
				   );

				if (starter_start_pluto(cfg, no_fork, attach_gdb) == 0)
				{
					starter_whack_listen();
				}
				else
				{
					/* schedule next try */
					alarm(PLUTO_RESTART_DELAY);
				}
			}
			_action_ &= ~FLAG_ACTION_START_PLUTO;

			for (ca = cfg->ca_first; ca; ca = ca->next)
			{
				if (ca->state == STATE_ADDED)
					ca->state = STATE_TO_ADD;
			}

			for (conn = cfg->conn_first; conn; conn = conn->next)
			{
				if (conn->state == STATE_ADDED)
					conn->state = STATE_TO_ADD;
			}
		}

		/*
		 * Start charon
		 */
		if (_action_ & FLAG_ACTION_START_CHARON)
		{
			if (cfg->setup.charonstart && !starter_charon_pid())
			{
				DBG(DBG_CONTROL,
					DBG_log("Attempting to start charon...")
				   );
				if (starter_start_charon(cfg, no_fork, attach_gdb))
				{
					/* schedule next try */
					alarm(PLUTO_RESTART_DELAY);
				}
				starter_stroke_configure(cfg);
			}
			_action_ &= ~FLAG_ACTION_START_CHARON;
		}

		/*
		 * Tell pluto to reread its interfaces
		 */
		if (_action_ & FLAG_ACTION_LISTEN)
		{
			if (starter_pluto_pid())
			{
				starter_whack_listen();
				_action_ &= ~FLAG_ACTION_LISTEN;
			}
		}

		/*
		 * Add stale conn and ca sections
		 */
		if (starter_pluto_pid() || starter_charon_pid())
		{
			for (ca = cfg->ca_first; ca; ca = ca->next)
			{
				if (ca->state == STATE_TO_ADD)
				{
					if (starter_charon_pid())
					{
						starter_stroke_add_ca(ca);
					}
					if (starter_pluto_pid())
					{
						starter_whack_add_ca(ca);
					}
					ca->state = STATE_ADDED;
				}
			}

			for (conn = cfg->conn_first; conn; conn = conn->next)
			{
				if (conn->state == STATE_TO_ADD)
				{
					if (conn->id == 0)
					{
						/* affect new unique id */
						conn->id = id++;
					}
					if (starter_charon_pid())
					{
						starter_stroke_add_conn(cfg, conn);
					}
					if (starter_pluto_pid())
					{
						starter_whack_add_conn(conn);
					}
					conn->state = STATE_ADDED;

					if (conn->startup == STARTUP_START)
					{
						if (conn->keyexchange == KEY_EXCHANGE_IKEV2)
						{
							if (starter_charon_pid())
							{
								starter_stroke_initiate_conn(conn);
							}
						}
						else
						{
							if (starter_pluto_pid())
							{
								starter_whack_initiate_conn(conn);
							}
						}
					}
					else if (conn->startup == STARTUP_ROUTE)
					{
						if (conn->keyexchange == KEY_EXCHANGE_IKEV2)
						{
							if (starter_charon_pid())
							{
								starter_stroke_route_conn(conn);
							}
						}
						else
						{
							if (starter_pluto_pid())
							{
								starter_whack_route_conn(conn);
							}
						}
					}
				}
			}
		}

		/*
		 * If auto_update activated, when to stop select
		 */
		if (auto_update)
		{
			time_t now = time_monotonic(NULL);

			tv.tv_sec = (now < last_reload + auto_update)
					? (last_reload + auto_update-now) : 0;
			tv.tv_usec = 0;
		}

		/*
		 * Wait for something to happen
		 */
		if (select(0, NULL, NULL, NULL, auto_update ? &tv : NULL) == 0)
		{
			/* timeout -> auto_update */
			_action_ |= FLAG_ACTION_UPDATE;
		}
	}
	exit(LSB_RC_SUCCESS);
}