/* $OpenBSD: isakmpd.c,v 1.109 2023/03/08 04:43:06 guenther 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/types.h>
#include <sys/stat.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <netdb.h>
#include <unistd.h>
#include <fcntl.h>
#include <paths.h>

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

#include "policy.h"

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;

/* Set when no policy file shall be used. */
int             acquire_only = 0;

/* Set when SAs shall be deleted on shutdown. */
int             delete_sas = 1;

/*
 * 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 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);
void            set_slave_signals(void);
void            sanitise_stdfd(void);

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

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

static void
usage(void)
{
        extern char *__progname;

        fprintf(stderr,
            "usage: %s [-46adKLnSTv] [-c config-file] [-D class=level] [-f fifo]\n"
            "          [-i pid-file] [-l packetlog-file] [-N udpencap-port]\n"
            "          [-p listen-port] [-R report-file]\n",
            __progname);
        exit(1);
}

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

        while ((ch = getopt(argc, argv, "46ac:dD:f:i:KnN:p:Ll:R:STv")) != -1) {
                switch (ch) {
                case '4':
                        bind_family |= BIND_FAMILY_INET4;
                        break;

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

                case 'a':
                        acquire_only = 1;
                        break;

                case 'c':
                        conf_path = optarg;
                        break;

                case 'd':
                        debug++;
                        break;

                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;

                case 'f':
                        ui_fifo = optarg;
                        break;

                case 'i':
                        pid_file = optarg;
                        break;

                case 'K':
                        ignore_policy++;
                        break;

                case 'n':
                        app_none++;
                        break;

                case 'N':
                        udp_encap_default_port = optarg;
                        break;

                case 'p':
                        udp_default_port = optarg;
                        break;

                case 'l':
                        pcap_file = optarg;
                        /* FALLTHROUGH */

                case 'L':
                        do_packetlog++;
                        break;

                case 'R':
                        report_file = optarg;
                        break;

                case 'S':
                        delete_sas = 0;
                        ui_daemon_passive = 1;
                        break;

                case 'T':
                        disable_nat_t = 1;
                        break;

                case 'v':
                        verbose_logging = 1;
                        break;

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

        if (argc > 0)   
                usage();

        if (do_packetlog && !pcap_file)
                pcap_file = PCAP_FILE_DEFAULT;
}

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);
}

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

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

static int
phase1_sa_check(struct sa *sa, void *arg)
{
        return sa->phase == 1;
}

void
set_slave_signals(void)
{
        int n;

        for (n = 1; n < _NSIG; n++)
                signal(n, SIG_DFL);

        /*
         * 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);

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

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

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...");

                if (delete_sas &&
                    strncmp("no", conf_get_str("General", "Delete-SAs"), 2)) {
                        /*
                         * Delete all active SAs.  First IPsec SAs, then
                         * ISAKMPD.  Each DELETE is another (outgoing) message.
                         */
                        while ((sa = sa_find(phase2_sa_check, NULL)))
                                sa_delete(sa, 1);

                        while ((sa = sa_find(phase1_sa_check, NULL)))
                                sa_delete(sa, 1);
                }

                /* We only want to do this once. */
                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.
                 */

                log_packet_stop();
                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;

        unlink(pid_file);

        fp = 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);
}

void
sanitise_stdfd(void)
{
        int nullfd, dupfd;

        if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
                fprintf(stderr, "Couldn't open /dev/null: %s\n",
                    strerror(errno));
                exit(1);
        }
        while (++dupfd <= STDERR_FILENO) {
                /* Only populate closed fds */
                if (fcntl(dupfd, F_GETFL) == -1 && errno == EBADF) {
                        if (dup2(nullfd, dupfd) == -1) {
                                fprintf(stderr, "dup2: %s\n", strerror(errno));
                                exit(1);
                        }
                }
        }
        if (nullfd > STDERR_FILENO)
                close(nullfd);
}

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

        closefrom(STDERR_FILENO + 1);

        /*
         * Make sure init() won't alloc fd 0, 1 or 2, as daemon() will close
         * them.
         */
        sanitise_stdfd();

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

        /* Open protocols and services databases.  */
        setprotoent(1);
        setservent(1);

        /* Open command fifo */
        ui_init();

        set_slave_signals();
        /* Daemonize before forking unpriv'ed child */
        if (!debug)
                if (daemon(0, 0))
                        log_fatal("main: daemon (0, 0) failed");

        /* Set timezone before priv'separation */
        tzset();

        write_pid_file();

        if (monitor_init(debug)) {
                /* The parent, with privileges enters infinite monitor loop. */
                monitor_loop(debug);
                exit(0);        /* Never reached.  */
        }
        /* Child process only from this point on, no privileges left.  */

        init();

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

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

        monitor_init_done();

        while (1) {
                /* If someone has sent SIGHUP to us, reconfigure.  */
                if (sighupped) {
                        sighupped = 0;
                        log_print("SIGHUP received");
                        reinit();
                }
                /* and if someone sent SIGUSR1, do a state report.  */
                if (sigusr1ed) {
                        sigusr1ed = 0;
                        log_print("SIGUSR1 received");
                        report();
                }
                /*
                 * 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.  */
                bzero(rfds, 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. */
                bzero(wfds, mask_size);
                m = transport_pending_wfd_set(wfds);
                if (m > n)
                        n = m;

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

                n = pselect(n, rfds, wfds, NULL, timeout, NULL);
                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();
        }
}