/* dhcrelay.c

   DHCP/BOOTP Relay Agent. */

/*
 * Copyright (c) 1997, 1998, 1999 The Internet Software Consortium.
 * 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.
 * 3. Neither the name of The Internet Software Consortium 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 INTERNET SOFTWARE CONSORTIUM 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 INTERNET SOFTWARE CONSORTIUM 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.
 *
 * This software has been written for the Internet Software Consortium
 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
 * Enterprises.  To learn more about the Internet Software Consortium,
 * see ``http://www.vix.com/isc''.  To learn more about Vixie
 * Enterprises, see ``http://www.vix.com''.
 */

#include "dhcpd.h"
#include "version.h"

static void usage PROTO ((char *));

TIME cur_time;
TIME default_lease_time = 43200; /* 12 hours... */
TIME max_lease_time = 86400; /* 24 hours... */
struct tree_cache *global_options [256];

int log_perror = 1;

/* Needed to prevent linking against conflex.c. */
int lexline;
int lexchar;
char *token_line;
char *tlname;

char *path_dhcrelay_pid = _PATH_DHCRELAY_PID;

u_int16_t local_port;
u_int16_t remote_port;
int log_priority;

struct server_list {
	struct server_list *next;
	struct sockaddr_in to;
} *servers;

static char copyright [] =
"Copyright 1997, 1998, 1999 The Internet Software Consortium.";
static char arr [] = "All rights reserved.";
static char message [] = "Internet Software Consortium DHCP Relay Agent";
static char contrib [] = "Please contribute if you find this software useful.";
static char url [] = "For info, please visit http://www.isc.org/dhcp-contrib.html";

int main (argc, argv, envp)
	int argc;
	char **argv, **envp;
{
	int i;
	struct servent *ent;
	struct server_list *sp = (struct server_list *)0;
	int no_daemon = 0;
	int quiet = 0;
	char *s;

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

	/* Initially, log errors to stderr as well as to syslogd. */
	openlog (s, LOG_NDELAY, DHCPD_LOG_FACILITY);

	setlogmask (LOG_UPTO (LOG_INFO));

	for (i = 1; i < argc; i++) {
		if (!strcmp (argv [i], "-p")) {
			if (++i == argc)
				usage (s);
			local_port = htons (atoi (argv [i]));
			debug ("binding to user-specified port %d",
			       ntohs (local_port));
		} else if (!strcmp (argv [i], "-pf")) {
			if (++i == argc)
				usage (s);
			path_dhcrelay_pid = argv [i];
		} else if (!strcmp (argv [i], "-d")) {
			no_daemon = 1;
 		} else if (!strcmp (argv [i], "-i")) {
			struct interface_info *tmp =
				((struct interface_info *)
				 dmalloc (sizeof *tmp, "specified_interface"));
			if (!tmp)
				error ("Insufficient memory to %s %s",
				       "record interface", argv [i]);
			if (++i == argc) {
				usage (s);
			}
			memset (tmp, 0, sizeof *tmp);
			strcpy (tmp -> name, argv [i]);
			tmp -> next = interfaces;
			tmp -> flags = INTERFACE_REQUESTED;
			interfaces = tmp;
		} else if (!strcmp (argv [i], "-q")) {
			quiet = 1;
			quiet_interface_discovery = 1;
 		} else if (argv [i][0] == '-') {
 		    usage (s);
 		} else {
			struct hostent *he;
			struct in_addr ia, *iap = (struct in_addr *)0;
			if (inet_aton (argv [i], &ia)) {
				iap = &ia;
			} else {
				he = gethostbyname (argv [i]);
				if (!he) {
					warn ("%s: host unknown", argv [i]);
				} else {
					iap = ((struct in_addr *)
					       he -> h_addr_list [0]);
				}
			}
			if (iap) {
				sp = (struct server_list *)malloc (sizeof *sp);
				if (!sp)
					error ("no memory for server.\n");
				sp -> next = servers;
				servers = sp;
				memcpy (&sp -> to.sin_addr,
					iap, sizeof *iap);
			}
 		}
	}

	if (!quiet) {
		note ("%s %s", message, DHCP_VERSION);
		note (copyright);
		note (arr);
		note ("");
		note (contrib);
		note (url);
		note ("");
	} else
		log_perror = 0;

	/* Default to the DHCP/BOOTP port. */
	if (!local_port) {
		ent = getservbyname ("dhcps", "udp");
		if (!ent)
			local_port = htons (67);
		else
			local_port = ent -> s_port;
		endservent ();
	}
	remote_port = htons (ntohs (local_port) + 1);
  
	/* We need at least one server. */
	if (!sp) {
		usage (s);
	}

	/* Set up the server sockaddrs. */
	for (sp = servers; sp; sp = sp -> next) {
		sp -> to.sin_port = local_port;
		sp -> to.sin_family = AF_INET;
		sp -> to.sin_len = sizeof sp -> to;
	}

	/* Get the current time... */
	GET_TIME (&cur_time);

	/* Discover all the network interfaces. */
	discover_interfaces (DISCOVER_RELAY);

	/* Set up the bootp packet handler... */
	bootp_packet_handler = relay;

	/* Become a daemon... */
	if (!no_daemon) {
		int pid;
		FILE *pf;
		int pfdesc;

		log_perror = 0;

		if ((pid = fork()) < 0)
			error ("can't fork daemon: %m");
		else if (pid)
			exit (0);

		pfdesc = open (path_dhcrelay_pid,
			       O_CREAT | O_TRUNC | O_WRONLY, 0644);

		if (pfdesc < 0) {
			warn ("Can't create %s: %m", path_dhcrelay_pid);
		} else {
			pf = fdopen (pfdesc, "w");
			if (!pf)
				warn ("Can't fdopen %s: %m",
				      path_dhcrelay_pid);
			else {
				fprintf (pf, "%ld\n", (long)getpid ());
				fclose (pf);
			}	
		}

		close (0);
		close (1);
		close (2);
		pid = setsid ();
	}

	/* Start dispatching packets and timeouts... */
	dispatch ();

	/*NOTREACHED*/
	return 0;
}

void relay (ip, packet, length, from_port, from, hfrom)
	struct interface_info *ip;
	struct dhcp_packet *packet;
	int length;
	unsigned int from_port;
	struct iaddr from;
	struct hardware *hfrom;
{
	struct server_list *sp;
	struct sockaddr_in to;
	struct interface_info *out;
	struct hardware hto;

	if (packet -> hlen > sizeof packet -> chaddr) {
		note ("Discarding packet with invalid hlen.");
		return;
	}

	/* If it's a bootreply, forward it to the client. */
	if (packet -> op == BOOTREPLY) {
		if (!(packet -> flags & htons (BOOTP_BROADCAST)) &&
		    can_unicast_without_arp ()) {
			to.sin_addr = packet -> yiaddr;
			to.sin_port = remote_port;
		} else {
			to.sin_addr.s_addr = htonl (INADDR_BROADCAST);
			to.sin_port = remote_port;
		}
		to.sin_family = AF_INET;
		to.sin_len = sizeof to;

		/* Set up the hardware destination address. */
		hto.hlen = packet -> hlen;
		if (hto.hlen > sizeof hto.haddr)
			hto.hlen = sizeof hto.haddr;
		memcpy (hto.haddr, packet -> chaddr, hto.hlen);
		hto.htype = packet -> htype;

		/* Find the interface that corresponds to the giaddr
		   in the packet. */
		for (out = interfaces; out; out = out -> next) {
			if (!memcmp (&out -> primary_address,
				     &packet -> giaddr,
				     sizeof packet -> giaddr))
				break;
		}
		if (!out) {
			warn ("packet to bogus giaddr %s.\n",
			      inet_ntoa (packet -> giaddr));
			return;
		}

		if (!send_packet (out,
				  (struct packet *)0,
				  packet, length, out -> primary_address,
				  &to, &hto) < 0)
			debug ("forwarded BOOTREPLY for %s to %s",
			       print_hw_addr (packet -> htype, packet -> hlen,
					      packet -> chaddr),
			       inet_ntoa (to.sin_addr));

		return;
	}

	/* If giaddr is set on a BOOTREQUEST, ignore it - it's already
	   been gatewayed. */
	if (packet -> giaddr.s_addr) {
		note ("ignoring BOOTREQUEST with giaddr of %s\n",
		      inet_ntoa (packet -> giaddr));
		return;
	}

	/* Set the giaddr so the server can figure out what net it's
	   from and so that we can later forward the response to the
	   correct net. */
	packet -> giaddr = ip -> primary_address;

	/* Otherwise, it's a BOOTREQUEST, so forward it to all the
	   servers. */
	for (sp = servers; sp; sp = sp -> next) {
		if (!send_packet ((fallback_interface
				   ? fallback_interface : interfaces),
				  (struct packet *)0,
				  packet, length, ip -> primary_address,
				  &sp -> to, (struct hardware *)0) < 0) {
			debug ("forwarded BOOTREQUEST for %s to %s",
			       print_hw_addr (packet -> htype, packet -> hlen,
					      packet -> chaddr),
			       inet_ntoa (sp -> to.sin_addr));
		}
	}
				 
}

static void usage (appname)
	char *appname;
{
	note (message);
	note (copyright);
	note (arr);
	note ("");
	note (contrib);
	note (url);
	note ("");

	warn ("Usage: %s [-i] [-d] [-i if0] [...-i ifN] [-p <port>]", appname);
	error ("      [-pf pidfilename] [server1 [... serverN]]");
}

void cleanup ()
{
}

int write_lease (lease)
	struct lease *lease;
{
	return 1;
}

int commit_leases ()
{
	return 1;
}

void bootp (packet)
	struct packet *packet;
{
}

void dhcp (packet)
	struct packet *packet;
{
}