/*	$NetBSD: rbootd.c,v 1.5 1995/10/06 05:12:17 thorpej Exp $	*/

/*
 * Copyright (c) 1988, 1992 The University of Utah and the Center
 *	for Software Science (CSS).
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Center for Software Science of the University of Utah Computer
 * Science Department.  CSS requests users of this software to return
 * to css-dist@cs.utah.edu any improvements that they make and grant
 * CSS redistribution rights.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 *
 *	from: @(#)rbootd.c	8.1 (Berkeley) 6/4/93
 *
 * From: Utah Hdr: rbootd.c 3.1 92/07/06
 * Author: Jeff Forys, University of Utah CSS
 */

#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1992, 1993\n\
	The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

#ifndef lint
/*static char sccsid[] = "@(#)rbootd.c	8.1 (Berkeley) 6/4/93";*/
static char rcsid[] = "$NetBSD: rbootd.c,v 1.5 1995/10/06 05:12:17 thorpej Exp $";
#endif /* not lint */

#include <sys/param.h>
#include <time.h>
#include <ctype.h>
#ifndef __linux__ /* not relevant to Linux */
#include <err.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "defs.h"

extern	char *__progname;	/* from crt0.o */

int
main(argc, argv)
	int argc;
	char *argv[];
{
	int c;
	sigset_t ss_block, ss_old;

#ifdef __linux__
        int nowtime; /* used in Linux version of timeout code */
#else
	int maxfds, fd;
	fd_set rset;
#endif

	/* initialize ss_block sigset with SIGHUP */
	sigemptyset(&ss_block);
	sigaddset(&ss_block, SIGHUP);

	/*
	 *  Close any open file descriptors.
	 *  Temporarily leave stdin & stdout open for `-d',
	 *  and stderr open for any pre-syslog error messages.
	 */
	{
		int i, nfds = getdtablesize();

		for (i = 0; i < nfds; i++)
			if (i != fileno(stdin) && i != fileno(stdout) &&
			    i != fileno(stderr))
				(void) close(i);
	}

	/*
	 *  Parse any arguments.
	 */
	while ((c = getopt(argc, argv, "adi:")) != EOF)
		switch(c) {
		    case 'a':
			BootAny++;
			break;
		    case 'd':
			DebugFlg++;
			break;
		    case 'i':
			IntfName = optarg;
			break;
		}
	for (; optind < argc; optind++) {
		if (ConfigFile == NULL)
			ConfigFile = argv[optind];
		else {
#ifdef __linux__ /* don't have warnx */
                    fprintf(stderr,"too many config files (`%s' ignored)\n",
                            argv[optind]);
#else
			warnx("too many config files (`%s' ignored)\n",
			    argv[optind]);
#endif
		}
	}

	if (ConfigFile == NULL)			/* use default config file */
		ConfigFile = DfltConfig;

	if (DebugFlg) {
		DbgFp = stdout;				/* output to stdout */

		(void) signal(SIGUSR1, SIG_IGN);	/* dont muck w/DbgFp */
		(void) signal(SIGUSR2, SIG_IGN);
		(void) fclose(stderr);			/* finished with it */
	} else {
		if (daemon(0, 0))
#ifndef __linux__
			err(1, "can't detach from terminal");
#else
                { /* Linux has no err() */
                   fprintf(stderr, "can't detach from terminal");
                   exit(1);
                }
#endif
 
		(void) signal(SIGUSR1, DebugOn);
		(void) signal(SIGUSR2, DebugOff);
	}

	openlog(__progname, LOG_PID, LOG_DAEMON);

	/*
	 *  If no interface was specified, get one now.
	 *
	 *  This is convoluted because we want to get the default interface
	 *  name for the syslog("restarted") message.  If BpfGetIntfName()
	 *  runs into an error, it will return a syslog-able error message
	 *  (in `errmsg') which will be displayed here.
	 */
	if (IntfName == NULL) {
		char *errmsg;
#ifdef __linux__
		char err_msg[PCAP_ERRBUF_SIZE];
		errmsg = err_msg;
		if ((IntfName = PcapGetIntfName(&errmsg)) == NULL ) {
#else
		if ((IntfName = BpfGetIntfName(&errmsg)) == NULL) {
#endif
			syslog(LOG_NOTICE, "restarted (%s)", "??");
			syslog(LOG_ERR, errmsg, 0);
			Exit(0);
		}
	}

	syslog(LOG_NOTICE, "restarted (%s)", IntfName);

	(void) signal(SIGHUP, ReConfig);
	(void) signal(SIGINT, Exit);
	(void) signal(SIGTERM, Exit);

	/*
	 *  Grab our host name and pid.
	 */
	if (gethostname(MyHost, MAXHOSTNAMELEN) < 0) {
		syslog(LOG_ERR, "gethostname: %m");
		Exit(0);
	}
	MyHost[MAXHOSTNAMELEN] = '\0';

	MyPid = getpid();

	/*
	 *  Write proc's pid to a file.
	 */
	{
		FILE *fp;

		if ((fp = fopen(PidFile, "w")) != NULL) {
			(void) fprintf(fp, "%d\n", (int) MyPid);
			(void) fclose(fp);
		} else {
			syslog(LOG_WARNING, "fopen: failed (%s)", PidFile);
		}
	}

	/*
	 *  All boot files are relative to the boot directory, we might
	 *  as well chdir() there to make life easier.
	 */
	if (chdir(BootDir) < 0) {
		syslog(LOG_ERR, "chdir: %m (%s)", BootDir);
		Exit(0);
	}

	/*
	 *  Initial configuration.
	 */
	sigprocmask(SIG_BLOCK, &ss_block, &ss_old); /* prevent reconfig's */
	if (GetBootFiles() == 0)		/* get list of boot files */
		Exit(0);
	if (ParseConfig() == 0)			/* parse config file */
		Exit(0);

#ifndef __linux__
/* This is a bit of a huge ifdef because the Linux main loop is totally 
   different due to the restrictions of the pcap functions...
   Analysis of main loop:
   First we initialise the packet filter.
   Then we wait for a packet (with possible timeout if also
   dealing with existing connections)
   If we timed out, we handle stale connections and loop
   If we error, exit.
   Otherwise we BpfRead the packet and deal with it.
   The while() loop and the doread variable are so that we
   read all packets that arrived this time, but no more
   (ie only read() on first packet of a bunch.)
   
   Adaptation to libpcap:
   We initialise the filter with pcap_open_live()
   and pcap_set_filter().
   Then we wait for packets and dispatch them
   to a function handle_pcap_packet() which we write
   (this will essentially be the innards of the while() loop)
   We can use pcap_dispatch() to deal with any
   packets currently available, putting this in a loop which
   tests the time and times out connections appropriately.
   PMM 1996 */

	/*
	 *  Open and initialize a BPF device for the appropriate interface.
	 *  If an error is encountered, a message is displayed and Exit()
	 *  is called.
	 */
	fd = BpfOpen();

        sigprocmask(SIG_SETMASK, &ss_old, NULL); /* allow reconfig's */

	/*
	 *  Main loop: receive a packet, determine where it came from,
	 *  and if we service this host, call routine to handle request.
	 */
	maxfds = fd + 1;
	FD_ZERO(&rset);
	FD_SET(fd, &rset);
	for (;;) {
		struct timeval timeout;
		fd_set r;
		int nsel;

		r = rset;

		if (RmpConns == NULL) {		/* timeout isnt necessary */
			nsel = select(maxfds, &r, NULL, NULL, NULL);
		} else {
			timeout.tv_sec = RMP_TIMEOUT;
			timeout.tv_usec = 0;
			nsel = select(maxfds, &r, NULL, NULL, &timeout);
		}

		if (nsel < 0) {
			if (errno == EINTR)
				continue;
			syslog(LOG_ERR, "select: %m");
			Exit(0);
		} else if (nsel == 0) {		/* timeout */
			DoTimeout();			/* clear stale conns */
			continue;
		}

		if (FD_ISSET(fd, &r)) {
			RMPCONN rconn;
			CLIENT *client, *FindClient();
			int doread = 1;

			while (BpfRead(&rconn, doread)) {
				doread = 0;

				if (DbgFp != NULL)	/* display packet */
					DispPkt(&rconn,DIR_RCVD);

				sigprocmask(SIG_BLOCK, &ss_block, &ss_old); /* prevent reconfig's */

				/*
				 *  If we do not restrict service, set the
				 *  client to NULL (ProcessPacket() handles
				 *  this).  Otherwise, check that we can
				 *  service this host; if not, log a message
				 *  and ignore the packet.
				 */
				if (BootAny) {
					client = NULL;
				} else if ((client=FindClient(&rconn))==NULL) {
					syslog(LOG_INFO,
					       "%s: boot packet ignored",
					       EnetStr(&rconn));
					sigprocmask(SIG_SETMASK, &ss_old, NULL); /* allow reconfig's */
					continue;
				}

				ProcessPacket(&rconn,client);
				sigprocmask(SIG_SETMASK, &ss_old, NULL); /* allow reconfig's */
			}
		}
	}
}

#else /* Linux main loop code below: */


/* Open and initialise a BPF filter */
    PcapOpen();
    sigprocmask(SIG_SETMASK, &ss_old, NULL); /* allow reconfig's */
    nowtime = time(NULL);
    for(;;)
    {
       /*
        *  Main loop: dispatch packets. After a given timeout, 
        *  check and delete stale connections.
        */
       if(PcapDispatch(DealWithPacket) < 0)
       {  /* error - logged already by PcapDispatch... */
          /* can we ever get errors that don't mean anything? */
       }
          
       if (time(NULL) > nowtime + RMP_TIMEOUT)
       {
          DoTimeout();  /* stale connection check */
          nowtime = time(NULL);
       }
    }
}

void DealWithPacket(RMPCONN rconn)
{
   /* this just deals with a single packet. code is
      from the while() loop of the NetBSD code */

   CLIENT* client;
   sigset_t ss_block, ss_old;

   if (DbgFp != NULL)	/* display packet */
      DispPkt(&rconn,DIR_RCVD);

   sigemptyset(&ss_block);
   sigaddset(&ss_block, SIGHUP);
   sigprocmask(SIG_BLOCK, &ss_block, &ss_old);
   
   /*
    *  If we do not restrict service, set the
    *  client to NULL (ProcessPacket() handles
    *  this).  Otherwise, check that we can
    *  service this host; if not, log a message
    *  and ignore the packet.
    */
   if (BootAny) {
      client = NULL;
   } else if ((client=FindClient(&rconn))==NULL) {
      syslog(LOG_INFO,
             "%s: boot packet ignored",
             EnetStr(&rconn));
   }
   else 
   {
      ProcessPacket(&rconn,client);
   }

   sigprocmask(SIG_SETMASK, &ss_old, NULL);
}

#endif /* __linux__ */

/*
**  DoTimeout -- Free any connections that have timed out.
**
**	Parameters:
**		None.
**
**	Returns:
**		Nothing.
**
**	Side Effects:
**		- Timed out connections in `RmpConns' will be freed.
*/
void
DoTimeout()
{
	register RMPCONN *rtmp;
	struct timeval now;

	(void) gettimeofday(&now, (struct timezone *)0);

	/*
	 *  For each active connection, if RMP_TIMEOUT seconds have passed
	 *  since the last packet was sent, delete the connection.
	 */
	for (rtmp = RmpConns; rtmp != NULL; rtmp = rtmp->next)
		if ((rtmp->tstamp.tv_sec + RMP_TIMEOUT) < now.tv_sec) {
			syslog(LOG_WARNING, "%s: connection timed out (%u)",
			       EnetStr(rtmp), rtmp->rmp.r_type);
			RemoveConn(rtmp);
		}
}

/*
**  FindClient -- Find client associated with a packet.
**
**	Parameters:
**		rconn - the new packet. 
**
**	Returns:
**		Pointer to client info if found, NULL otherwise.
**
**	Side Effects:
**		None.
**
**	Warnings:
**		- This routine must be called with SIGHUP blocked since
**		  a reconfigure can invalidate the information returned.
*/

CLIENT *
FindClient(rconn)
	register RMPCONN *rconn;
{
	register CLIENT *ctmp;

	for (ctmp = Clients; ctmp != NULL; ctmp = ctmp->next)
		if (bcmp((char *)&rconn->rmp.hp_hdr.saddr[0],
		         (char *)&ctmp->addr[0], RMP_ADDRLEN) == 0)
			break;

	return(ctmp);
}

/*
**  Exit -- Log an error message and exit.
**
**	Parameters:
**		sig - caught signal (or zero if not dying on a signal).
**
**	Returns:
**		Does not return.
**
**	Side Effects:
**		- This process ceases to exist.
*/
void
Exit(sig)
	int sig;
{
	if (sig > 0)
		syslog(LOG_ERR, "going down on signal %d", sig);
	else
		syslog(LOG_ERR, "going down with fatal error");
#ifdef __linux__
        PcapClose();
#else
	BpfClose();
#endif
	exit(sig > 0 ? 0:1);
}

/*
**  ReConfig -- Get new list of boot files and reread config files.
**
**	Parameters:
**		None.
**
**	Returns:
**		Nothing.
**
**	Side Effects:
**		- All active connections are dropped.
**		- List of boot-able files is changed.
**		- List of clients is changed.
**
**	Warnings:
**		- This routine must be called with SIGHUP blocked.
*/
void
ReConfig(signo)
	int signo;
{
	syslog(LOG_NOTICE, "reconfiguring boot server");

	FreeConns();

	if (GetBootFiles() == 0)
		Exit(0);

	if (ParseConfig() == 0)
		Exit(0);
}

/*
**  DebugOff -- Turn off debugging.
**
**	Parameters:
**		None.
**
**	Returns:
**		Nothing.
**
**	Side Effects:
**		- Debug file is closed.
*/
void
DebugOff(signo)
	int signo;
{
	if (DbgFp != NULL)
		(void) fclose(DbgFp);

	DbgFp = NULL;
}

/*
**  DebugOn -- Turn on debugging.
**
**	Parameters:
**		None.
**
**	Returns:
**		Nothing.
**
**	Side Effects:
**		- Debug file is opened/truncated if not already opened,
**		  otherwise do nothing.
*/
void
DebugOn(signo)
	int signo;
{
	if (DbgFp == NULL) {
		if ((DbgFp = fopen(DbgFile, "w")) == NULL)
			syslog(LOG_ERR, "can't open debug file (%s)", DbgFile);
	}
}