/*
 *  Copyright (c) 1998 by the University of Southern California.
 *  All rights reserved.
 *
 *  Permission to use, copy, modify, and distribute this software and
 *  its documentation in source and binary forms for lawful
 *  purposes and without fee is hereby granted, provided
 *  that the above copyright notice appear in all copies and that both
 *  the copyright notice and this permission notice appear in supporting
 *  documentation, and that any documentation, advertising materials,
 *  and other materials related to such distribution and use acknowledge
 *  that the software was developed by the University of Southern
 *  California and/or Information Sciences Institute.
 *  The name of the University of Southern California may not
 *  be used to endorse or promote products derived from this software
 *  without specific prior written permission.
 *
 *  THE UNIVERSITY OF SOUTHERN CALIFORNIA DOES NOT MAKE ANY REPRESENTATIONS
 *  ABOUT THE SUITABILITY OF THIS SOFTWARE FOR ANY PURPOSE.  THIS SOFTWARE IS
 *  PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
 *  INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND
 *  NON-INFRINGEMENT.
 *
 *  IN NO EVENT SHALL USC, OR ANY OTHER CONTRIBUTOR BE LIABLE FOR ANY
 *  SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES, WHETHER IN CONTRACT,
 *  TORT, OR OTHER FORM OF ACTION, ARISING OUT OF OR IN CONNECTION WITH,
 *  THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 *  Other copyrights might apply to parts of this software and are so
 *  noted when applicable.
 */
/*
 *  Questions concerning this software should be directed to
 *  Mickael Hoerdt (hoerdt@clarinet.u-strasbg.fr) LSIIT Strasbourg.
 *
 */
/*
 * This program has been derived from pim6dd.        
 * The pim6dd program is covered by the license in the accompanying file
 * named "LICENSE.pim6dd".
 */
/*
 * This program has been derived from pimd.        
 * The pimd program is covered by the license in the accompanying file
 * named "LICENSE.pimd".
 *
 */
/*
 * Part of this program has been derived from mrouted.
 * The mrouted program is covered by the license in the accompanying file
 * named "LICENSE.mrouted".
 *
 * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
 * Leland Stanford Junior University.
 *
 * $FreeBSD$
 */

#include <sys/param.h>
#include <sys/time.h>
#include <errno.h>
#include <paths.h>
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <syslog.h>
#include <fcntl.h>
#include "pathnames.h"
#include "defs.h"
#include "debug.h"
#include "mld6.h"
#include "pim6.h"
#include "vif.h"
#include "routesock.h"
#include "callout.h"
#include "mrt.h"
#include "timer.h"
#include "rp.h"
#include "kern.h"
#include "cfparse.h"

char            	configfilename[256] = _PATH_PIM6D_CONF;
char            	versionstring[100];
char			logfilename[256] = _PATH_PIM6D_LOGFILE;

/* TODO: not used 
static char 		genidfilename[] = _PATH_PIM6D_GENID;
*/
static char     	pidfilename[] = _PATH_PIM6D_PID;

FILE			*log_fp = stderr;
char           		*progname;

static int		foreground = 0;
static int      	sighandled = 0;

#define GOT_SIGINT      0x01
#define GOT_SIGHUP      0x02
#define GOT_SIGUSR1     0x04
#define GOT_SIGUSR2     0x08
#define GOT_SIGALRM     0x10
#define GOT_SIGINFO	0x20


#define NHANDLERS       3

static struct ihandler
{
    int             fd;		/* File descriptor               */
    ihfunc_t        func;	/* Function to call with &fd_set */
}	ihandlers[NHANDLERS];

static int      nhandlers = 0;

static struct debugname
{
    char           *name;
    int             level;
    int             nchars;
}               debugnames[] = {
    {   "mld_proto",	DEBUG_MLD_PROTO,		5     },
    {   "mld_timer",	DEBUG_MLD_TIMER,		5     },
    {   "mld_member",	DEBUG_MLD_MEMBER,		5     },
    {   "mld",			DEBUG_MLD,		3     },
    {   "switch",		DEBUG_SWITCH,		2     },
    {   "trace",		DEBUG_TRACE,		2     },
    {   "mtrace",		DEBUG_TRACE,		2     },
    {   "traceroute",		DEBUG_TRACE,		2     },
    {   "timeout",		DEBUG_TIMEOUT,		2     },
    {   "callout",		DEBUG_TIMEOUT,		3     },
    {   "pkt",			DEBUG_PKT,		2     },
    {   "packets",		DEBUG_PKT,		2     },
    {   "interfaces",		DEBUG_IF,		2     },
    {   "vif",			DEBUG_IF,		1     },
    {   "kernel",		DEBUG_KERN,		2     },
    {   "cache",		DEBUG_MFC,		1     },
    {   "mfc",			DEBUG_MFC,		2     },
    {   "k_cache",		DEBUG_MFC,		2     },
    {   "k_mfc",		DEBUG_MFC,		2     },
    {   "rsrr",			DEBUG_RSRR,		2     },
    {   "pim_detail",		DEBUG_PIM_DETAIL,	5     },
    {   "pim_hello",		DEBUG_PIM_HELLO,	5     },
    {   "pim_neighbors",	DEBUG_PIM_HELLO,	5     },
    {   "pim_register",		DEBUG_PIM_REGISTER,	5     },
    {   "registers",		DEBUG_PIM_REGISTER,	2     },
    {   "pim_join_prune",	DEBUG_PIM_JOIN_PRUNE,	5     },
    {   "pim_j_p",		DEBUG_PIM_JOIN_PRUNE,	5     },
    {   "pim_jp",		DEBUG_PIM_JOIN_PRUNE,	5     },
    {   "pim_bootstrap",	DEBUG_PIM_BOOTSTRAP,	5     },
    {   "pim_bsr",		DEBUG_PIM_BOOTSTRAP,	5     },
    {   "bsr",			DEBUG_PIM_BOOTSTRAP,	1     },
    {   "bootstrap",		DEBUG_PIM_BOOTSTRAP,	1     },
    {   "pim_asserts",		DEBUG_PIM_ASSERT,	5     },
    {   "pim_cand_rp",		DEBUG_PIM_CAND_RP,	5     },
    {   "pim_c_rp",		DEBUG_PIM_CAND_RP,	5     },
    {   "pim_rp",		DEBUG_PIM_CAND_RP,	6     },
    {   "rp",			DEBUG_PIM_CAND_RP,	2     },
    {   "pim_routes",		DEBUG_PIM_MRT,		6     },
    {   "pim_routing",		DEBUG_PIM_MRT,		6     },
    {   "pim_mrt",		DEBUG_PIM_MRT,		5     },
    {   "pim_timers",		DEBUG_PIM_TIMER,	5     },
    {   "pim_rpf",		DEBUG_PIM_RPF,		6     },
    {   "rpf",			DEBUG_RPF,		3     },
    {   "pim",			DEBUG_PIM,		1     },
    {   "routes",		DEBUG_MRT,		1     },
    {   "routing",		DEBUG_MRT,		1     },
    {   "mrt",			DEBUG_MRT,		1     },
    {   "routers",		DEBUG_NEIGHBORS,	6     },
    {   "mrouters",		DEBUG_NEIGHBORS,	7     },
    {   "neighbors",		DEBUG_NEIGHBORS,	1     },
    {   "timers",		DEBUG_TIMER,		1     },
    {   "asserts",		DEBUG_ASSERT,		1     },
    {   "all",			DEBUG_ALL,		2     },
    {   "3",			0xffffffff,		1     }    /* compat. */
};


/*
 * Forward declarations.
 */

static void handler __P((int));
static void timer   __P((void *));
static void cleanup __P((void));
static void restart __P((int));
static void cleanup __P((void));


/* To shut up gcc -Wstrict-prototypes */

int main        __P((int argc, char **argv));

int
register_input_handler(fd, func)
    int             fd;
    ihfunc_t        func;
{
    if (nhandlers >= NHANDLERS)
	return -1;

    ihandlers[nhandlers].fd = fd;
    ihandlers[nhandlers++].func = func;

    return 0;
}

int
main(argc, argv)
    int             argc;
    char           *argv[];
{
    int             dummy,
                    dummysigalrm;
    FILE           *fp;
    struct timeval  tv,
                    difftime,
                    curtime,
                    lasttime,
                   *timeout;
    fd_set          rfds,
                    readers;
    int             nfds=0,
                    n,
                    i,
                    secs;
    extern char     todaysversion[];
    struct sigaction sa;
    struct debugname *d;
    char            c;
    int             tmpd;

    setlinebuf(stderr);

    if (geteuid() != 0)
    {
	fprintf(stderr, "pim6sd: must be root\n");
	exit(1);
    }

    progname = strrchr(argv[0], '/');
    if (progname)
	progname++;
    else
	progname = argv[0];

    argv++;
    argc--;
    while (argc > 0 && *argv[0] == '-')
    {
	if (strcmp(*argv, "-d") == 0)
	{
	    if (argc > 1 && *(argv + 1)[0] != '-')
	    {
		char           *p,
		               *q;
		int             i,
		                len;
		struct debugname *d;
		int 		no=0;

		argv++;
		argc--;
		debug = 0;
		p = *argv;
		q = NULL;
		while (p)
		{
		    q = strchr(p, ',');
		    if (q)
			*q++ = '\0';
		    if(p[0]=='-')
		    {
			no=1;
			p++;
		    }		
		    len = strlen(p);
		    for (i = 0, d = debugnames;
			 i < sizeof(debugnames) / sizeof(debugnames[0]);
			 i++, d++)
			if (len >= d->nchars && strncmp(d->name, p, len) == 0)
			    break;
		    if (i == sizeof(debugnames) / sizeof(debugnames[0]))
		    {
			int             j = 0xffffffff;
			int             k = 0;
			fprintf(stderr, "Valid debug levels: ");
			for (i = 0, d = debugnames;
			     i < sizeof(debugnames) / sizeof(debugnames[0]);
			     i++, d++)
			{
			    if ((j & d->level) == d->level)
			    {
				if (k++)
				    putc(',', stderr);
				fputs(d->name, stderr);
				j &= ~d->level;
			    }
			}
			putc('\n', stderr);
			goto usage;
		    }
		    if(no)
		    {
			debug &=~d->level;
			no=0;
		    }
		    else
			debug |= d->level;
		    p = q;
		}
	    }
	    else
		debug = DEBUG_DEFAULT;
	}
	else if (strcmp(*argv, "-c") == 0) {
		if (argc > 1)
		{
		    argv++;
		    argc--;
		    strcpy(configfilename, *argv);
		}
		else
		    goto usage;
	}
	else if (strcmp(*argv, "-f") == 0)
		foreground = 1;
	else
		    goto usage;

	argv++;
	argc--;
    }

    if (argc > 0)
    {
usage:
	tmpd = 0xffffffff;
	fprintf(stderr, "usage: pim6sd [-c configfile] [-d [debug_level][,debug_level]]\n");

	fprintf(stderr, "debug levels: ");
	c = '(';
	for (d = debugnames; d < debugnames +
	     sizeof(debugnames) / sizeof(debugnames[0]); d++)
	{
	    if ((tmpd & d->level) == d->level)
	    {
		tmpd &= ~d->level;
		fprintf(stderr, "%c%s", c, d->name);
		c = ',';
	    }
	}
	fprintf(stderr, ")\n");
	exit(1);
    }

    if (debug != 0)
    {
	tmpd = debug;
	fprintf(stderr, "debug level 0x%lx ", debug);
	c = '(';
	for (d = debugnames; d < debugnames +
	     sizeof(debugnames) / sizeof(debugnames[0]); d++)
	{
	    if ((tmpd & d->level) == d->level)
	    {
		tmpd &= ~d->level;
		fprintf(stderr, "%c%s", c, d->name);
		c = ',';
	    }
	}
	fprintf(stderr, ")\n");
    }

#ifdef LOG_DAEMON
    (void) openlog("pim6sd", LOG_PID, LOG_DAEMON);
//  (void) setlogmask(LOG_UPTO(LOG_NOTICE));
#else
    (void) openlog("pim6sd", LOG_PID);
#endif				/* LOG_DAEMON */
    /* open a log file */
    if ((log_fp = fopen(logfilename, "w")) == NULL)
	    log(LOG_ERR, errno, "fopen(%s)", logfilename);
    setlinebuf(log_fp);

    sprintf(versionstring, "pim6sd version %s", todaysversion);

    log(LOG_INFO, 0, "%s starting", versionstring);

    /*
     * TODO: XXX: use a combination of time and hostid to initialize the
     * random generator.
     */

#ifdef SYSV
    srand48(time(NULL));
#else
    srandom(time(NULL));
#endif

    callout_init();
    init_mld6();
    init_pim6();

#ifdef HAVE_ROUTING_SOCKETS
    init_routesock();
#endif				/* HAVE_ROUTING_SOCKETS */

    init_pim6_mrt();
    init_timers();

    /* TODO: check the kernel DVMRP/MROUTED/PIM support version */

    init_vifs();
    init_rp6_and_bsr6();	/* Must be after init_vifs() */

    sa.sa_handler = handler;
    sa.sa_flags = 0;		/* Interrupt system calls */
    sigemptyset(&sa.sa_mask);
    sigaction(SIGALRM, &sa, NULL);
    sigaction(SIGHUP, &sa, NULL);
    sigaction(SIGTERM, &sa, NULL);
    sigaction(SIGINT, &sa, NULL);
    sigaction(SIGUSR1, &sa, NULL);
    sigaction(SIGUSR2, &sa, NULL);
    sigaction(SIGINFO, &sa, NULL);

    FD_ZERO(&readers);
    FD_SET(mld6_socket, &readers);
    for (i = 0; i < nhandlers; i++)
    {
	FD_SET(ihandlers[i].fd, &readers);
	if (ihandlers[i].fd >= nfds)
	    nfds = ihandlers[i].fd + 1;
    }

    IF_DEBUG(DEBUG_IF)
	dump_vifs(log_fp);
    IF_DEBUG(DEBUG_PIM_MRT)
	dump_pim_mrt(log_fp);

    /* schedule first timer interrupt */
    timer_setTimer(timer_interval, timer, NULL);

    if (foreground == 0)
    {
	/* Detach from the terminal */
#ifdef TIOCNOTTY
	int             t;
#endif				/* TIOCNOTTY */

	if (fork())
	    exit(0);

#ifdef HAVE_ROUTING_SOCKETS
	pid = getpid();
#endif
	(void) close(0);
	(void) close(1);
	(void) close(2);
	(void) open("/", 0);
	(void) dup2(0, 1);
	(void) dup2(0, 2);

#if defined(SYSV) || defined(linux)
	(void) setpgrp();
#else
#ifdef TIOCNOTTY
	t = open(_PATH_TTY, 2);
	if (t >= 0)
	{
	    (void) ioctl(t, TIOCNOTTY, (char *) 0);
	    (void) close(t);
	}
#else
	if (setsid() < 0)
	    perror("setsid");
#endif				/* TIOCNOTTY */
#endif				/* SYSV */
    }				/* End of child process code */

    fp = fopen(pidfilename, "w");
    if (fp != NULL)
    {
	fprintf(fp, "%d\n", (int) getpid());
	(void) fclose(fp);
    }

    /*
     * Main receive loop.
     */
    dummy = 0;
    dummysigalrm = SIGALRM;
    difftime.tv_usec = 0;
    gettimeofday(&curtime, NULL);
    lasttime = curtime;
    for (;;)
    {
	bcopy((char *) &readers, (char *) &rfds, sizeof(rfds));
	secs = timer_nextTimer();
	if (secs == -1)
	    timeout = NULL;
	else
	{
	    timeout = &tv;
	    timeout->tv_sec = secs;
	    timeout->tv_usec = 0;
	}

	if (sighandled)
	{
	    if (sighandled & GOT_SIGINT)
	    {
		sighandled &= ~GOT_SIGINT;
		break;
	    }
	    if (sighandled & GOT_SIGHUP)
	    {
		sighandled &= ~GOT_SIGHUP;
		restart(SIGHUP);
	    }
	    if (sighandled & GOT_SIGINFO)
	    {
		sighandled &= ~GOT_SIGINFO;
		dump_stat();
	    }
	    if (sighandled & GOT_SIGUSR1)
	    {
		sighandled &= ~GOT_SIGUSR1;
		fdump(SIGUSR1);
	    }
	    if (sighandled & GOT_SIGUSR2)
	    {
		sighandled &= ~GOT_SIGUSR2;
#ifdef notyet
		cdump(SIGUSR2);
#else
		cfparse(0, 1);	/* reset debug level */
#endif
	    }
	    if (sighandled & GOT_SIGALRM)
	    {
		sighandled &= ~GOT_SIGALRM;
		timer(&dummysigalrm);
	    }
	}
	if ((n = select(nfds, &rfds, NULL, NULL, timeout)) < 0)
	{
	    if (errno != EINTR)	
		log(LOG_WARNING, errno, "select failed");
	    continue;
	}

	/*
	 * Handle timeout queue.
	 * 
	 * If select + packet processing took more than 1 second, or if there is
	 * a timeout pending, age the timeout queue.
	 * 
	 * If not, collect usec in difftime to make sure that the time doesn't
	 * drift too badly.
	 * 
	 * If the timeout handlers took more than 1 second, age the timeout
	 * queue again.  XXX This introduces the potential for infinite
	 * loops!
	 */
	do
	{
	    /*
	     * If the select timed out, then there's no other activity to
	     * account for and we don't need to call gettimeofday.
	     */
	    if (n == 0)
	    {
		curtime.tv_sec = lasttime.tv_sec + secs;
		curtime.tv_usec = lasttime.tv_usec;
		n = -1;		/* don't do this next time through the loop */
	    }
	    else
		gettimeofday(&curtime, NULL);
	    difftime.tv_sec = curtime.tv_sec - lasttime.tv_sec;
	    difftime.tv_usec += curtime.tv_usec - lasttime.tv_usec;
#ifdef TIMERDEBUG
	    IF_DEBUG(DEBUG_TIMEOUT)
		log(LOG_DEBUG, 0, "TIMEOUT: secs %d, diff secs %d, diff usecs %d", secs, difftime.tv_sec, difftime.tv_usec);
#endif
	    while (difftime.tv_usec >= 1000000)
	    {
		difftime.tv_sec++;
		difftime.tv_usec -= 1000000;
	    }
	    if (difftime.tv_usec < 0)
	    {
		difftime.tv_sec--;
		difftime.tv_usec += 1000000;
	    }
	    lasttime = curtime;
	    if (secs == 0 || difftime.tv_sec > 0)
		if (secs == 0 || difftime.tv_sec > 0)
		{
#ifdef TIMERDEBUG
		    IF_DEBUG(DEBUG_TIMEOUT)
			log(LOG_DEBUG, 0, "\taging callouts: secs %d, diff secs %d, diff usecs %d", secs, difftime.tv_sec, difftime.tv_usec);
#endif
		    age_callout_queue(difftime.tv_sec);
		}
	    secs = -1;
	} while (difftime.tv_sec > 0);

	/* Handle sockets */
	if (n > 0)
	{
	    for (i = 0; i < nhandlers; i++)
	    {
		if (FD_ISSET(ihandlers[i].fd, &rfds))
		{
		    (*ihandlers[i].func) (ihandlers[i].fd, &rfds);
		}
	    }
	}

    }				/* Main loop */

    log(LOG_NOTICE, 0, "%s exiting", versionstring);
    cleanup();
    exit(0);
}

/*
 * The 'virtual_time' variable is initialized to a value that will cause the
 * first invocation of timer() to send a probe or route report to all vifs
 * and send group membership queries to all subnets for which this router is
 * querier.  This first invocation occurs approximately timer_interval
 * seconds after the router starts up.   Note that probes for neighbors and
 * queries for group memberships are also sent at start-up time, as part of
 * initial- ization.  This repetition after a short interval is desirable for
 * quickly building up topology and membership information in the presence of
 * possible packet loss.
 * 
 * 'virtual_time' advances at a rate that is only a crude approximation of real
 * time, because it does not take into account any time spent processing, and
 * because the timer intervals are sometimes shrunk by a random amount to
 * avoid unwanted synchronization with other routers.
 */

u_long          virtual_time = 0;

/*
 * Timer routine. Performs all perodic functions: aging interfaces, quering
 * neighbors and members, etc... The granularity is equal to timer_interval.
 * this granularity is configurable ( see file pim6sd.conf.sample)
 */

static void
timer(i)
    void           *i;
{
    age_vifs();			/* Timeout neighbors and groups         */
    age_routes();		/* Timeout routing entries              */
    age_misc();			/* Timeout the rest (Cand-RP list, etc) */

    virtual_time += timer_interval;
    timer_setTimer(timer_interval, timer, NULL);
}

/*
 * Performs all necessary functions to quit gracefully
 */
/* TODO: implement all necessary stuff */

static void
cleanup()
{

    /*
     * TODO: XXX (not in the spec): if I am the BSR, somehow inform the other
     * routers I am going down and need to elect another BSR? (probably by
     * sending a the Cand-RP-set with my_priority=LOWEST?)
     * 
     */ 
	
     k_stop_pim(mld6_socket);
}


/*
 * Signal handler.  Take note of the fact that the signal arrived so that the
 * main loop can take care of it.
 */
static void
handler(sig)
    int             sig;
{
    switch (sig)
    {
    case SIGALRM:
	sighandled |= GOT_SIGALRM;
    case SIGINT:
    case SIGTERM:
	sighandled |= GOT_SIGINT;
	break;

    case SIGHUP:
	sighandled |= GOT_SIGHUP;
	break;

    case SIGUSR1:
	sighandled |= GOT_SIGUSR1;
	break;

    case SIGUSR2:
	sighandled |= GOT_SIGUSR2;
	break;

    case SIGINFO:
	sighandled |= GOT_SIGINFO;
	break;
    }
}


/* TODO: not verified */
/*
 * Restart the daemon
 */

static void
restart(i)
    int             i;
{

    log(LOG_NOTICE, 0, "%s restart", versionstring);

    /*
     * reset all the entries
     */
    /*
     * TODO: delete? 
    free_all_routes();
     */

    free_all_callouts();
    stop_all_vifs();
    nhandlers=0;
    k_stop_pim(mld6_socket);
    close(mld6_socket);
    close(pim6_socket);
    close(udp_socket);

    /*
     * start processing again
     */

    init_mld6();
    init_pim6();

#ifdef HAVE_ROUTING_SOCKETS
    init_routesock();
#endif				/* HAVE_ROUTING_SOCKETS */

    init_pim6_mrt();
    init_vifs();

    /* schedule timer interrupts */
    timer_setTimer(timer_interval, timer, NULL);
}