/*
 * Copyright (C) 2012 by Darren Reed.
 *
 * See the IPFILTER.LICENCE file for details on licencing.
 */
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#if !defined(__SVR4) && !defined(__GNUC__)
#include <strings.h>
#endif
#include <sys/types.h>
#include <sys/param.h>
#include <sys/file.h>
#include <stdlib.h>
#include <stddef.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <sys/time.h>
#include <net/if.h>
#include <netinet/ip.h>
#include <netdb.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include "ipf.h"
#include "netinet/ipl.h"

#if !defined(lint)
static const char rcsid[] = "@(#)$Id$";
#endif

#ifndef	IPF_SAVEDIR
# define	IPF_SAVEDIR	"/var/db/ipf"
#endif
#ifndef IPF_NATFILE
# define	IPF_NATFILE	"ipnat.ipf"
#endif
#ifndef IPF_STATEFILE
# define	IPF_STATEFILE	"ipstate.ipf"
#endif

#if !defined(__SVR4) && defined(__GNUC__)
extern	char	*index(const char *, int);
#endif

extern	char	*optarg;
extern	int	optind;

int	main(int, char *[]);
void	usage(void);
int	changestateif(char *, char *);
int	changenatif(char *, char *);
int	readstate(int, char *);
int	readnat(int, char *);
int	writestate(int, char *);
int	opendevice(char *);
void	closedevice(int);
int	setlock(int, int);
int	writeall(char *);
int	readall(char *);
int	writenat(int, char *);

int	opts = 0;
char	*progname;


void usage()
{
	fprintf(stderr, "usage: %s [-nv] -l\n", progname);
	fprintf(stderr, "usage: %s [-nv] -u\n", progname);
	fprintf(stderr, "usage: %s [-nv] [-d <dir>] -R\n", progname);
	fprintf(stderr, "usage: %s [-nv] [-d <dir>] -W\n", progname);
	fprintf(stderr, "usage: %s [-nNSv] [-f <file>] -r\n", progname);
	fprintf(stderr, "usage: %s [-nNSv] [-f <file>] -w\n", progname);
	fprintf(stderr, "usage: %s [-nNSv] -f <filename> -i <if1>,<if2>\n",
		progname);
	exit(1);
}


/*
 * Change interface names in state information saved out to disk.
 */
int changestateif(char *ifs, char *fname)
{
	int fd, olen, nlen, rw;
	ipstate_save_t ips;
	off_t pos;
	char *s;

	s = strchr(ifs, ',');
	if (!s)
		usage();
	*s++ = '\0';
	nlen = strlen(s);
	olen = strlen(ifs);
	if (nlen >= sizeof(ips.ips_is.is_ifname) ||
	    olen >= sizeof(ips.ips_is.is_ifname))
		usage();

	fd = open(fname, O_RDWR);
	if (fd == -1) {
		perror("open");
		exit(1);
	}

	for (pos = 0; read(fd, &ips, sizeof(ips)) == sizeof(ips); ) {
		rw = 0;
		if (!strncmp(ips.ips_is.is_ifname[0], ifs, olen + 1)) {
			strcpy(ips.ips_is.is_ifname[0], s);
			rw = 1;
		}
		if (!strncmp(ips.ips_is.is_ifname[1], ifs, olen + 1)) {
			strcpy(ips.ips_is.is_ifname[1], s);
			rw = 1;
		}
		if (!strncmp(ips.ips_is.is_ifname[2], ifs, olen + 1)) {
			strcpy(ips.ips_is.is_ifname[2], s);
			rw = 1;
		}
		if (!strncmp(ips.ips_is.is_ifname[3], ifs, olen + 1)) {
			strcpy(ips.ips_is.is_ifname[3], s);
			rw = 1;
		}
		if (rw == 1) {
			if (lseek(fd, pos, SEEK_SET) != pos) {
				perror("lseek");
				exit(1);
			}
			if (write(fd, &ips, sizeof(ips)) != sizeof(ips)) {
				perror("write");
				exit(1);
			}
		}
		pos = lseek(fd, 0, SEEK_CUR);
	}
	close(fd);

	return (0);
}


/*
 * Change interface names in NAT information saved out to disk.
 */
int changenatif(char *ifs, char *fname)
{
	int fd, olen, nlen, rw;
	nat_save_t ipn;
	nat_t *nat;
	off_t pos;
	char *s;

	s = strchr(ifs, ',');
	if (!s)
		usage();
	*s++ = '\0';
	nlen = strlen(s);
	olen = strlen(ifs);
	nat = &ipn.ipn_nat;
	if (nlen >= sizeof(nat->nat_ifnames[0]) ||
	    olen >= sizeof(nat->nat_ifnames[0]))
		usage();

	fd = open(fname, O_RDWR);
	if (fd == -1) {
		perror("open");
		exit(1);
	}

	for (pos = 0; read(fd, &ipn, sizeof(ipn)) == sizeof(ipn); ) {
		rw = 0;
		if (!strncmp(nat->nat_ifnames[0], ifs, olen + 1)) {
			strcpy(nat->nat_ifnames[0], s);
			rw = 1;
		}
		if (!strncmp(nat->nat_ifnames[1], ifs, olen + 1)) {
			strcpy(nat->nat_ifnames[1], s);
			rw = 1;
		}
		if (rw == 1) {
			if (lseek(fd, pos, SEEK_SET) != pos) {
				perror("lseek");
				exit(1);
			}
			if (write(fd, &ipn, sizeof(ipn)) != sizeof(ipn)) {
				perror("write");
				exit(1);
			}
		}
		pos = lseek(fd, 0, SEEK_CUR);
	}
	close(fd);

	return (0);
}


int main(int argc, char *argv[])
{
	int c, lock = -1, devfd = -1, err = 0, rw = -1, ns = -1, set = 0;
	char *dirname = NULL, *filename = NULL, *ifs = NULL;

	progname = argv[0];
	while ((c = getopt(argc, argv, "d:f:i:lNnSRruvWw")) != -1)
		switch (c)
		{
		case 'd' :
			if ((set == 0) && !dirname && !filename)
				dirname = optarg;
			else
				usage();
			break;
		case 'f' :
			if ((set != 0) && !dirname && !filename)
				filename = optarg;
			else
				usage();
			break;
		case 'i' :
			ifs = optarg;
			set = 1;
			break;
		case 'l' :
			if (filename || dirname || set)
				usage();
			lock = 1;
			set = 1;
			break;
		case 'n' :
			opts |= OPT_DONOTHING;
			break;
		case 'N' :
			if ((ns >= 0) || dirname || (rw != -1) || set)
				usage();
			ns = 0;
			set = 1;
			break;
		case 'r' :
			if (dirname || (rw != -1) || (ns == -1))
				usage();
			rw = 0;
			set = 1;
			break;
		case 'R' :
			rw = 2;
			set = 1;
			break;
		case 'S' :
			if ((ns >= 0) || dirname || (rw != -1) || set)
				usage();
			ns = 1;
			set = 1;
			break;
		case 'u' :
			if (filename || dirname || set)
				usage();
			lock = 0;
			set = 1;
			break;
		case 'v' :
			opts |= OPT_VERBOSE;
			break;
		case 'w' :
			if (dirname || (rw != -1) || (ns == -1))
				usage();
			rw = 1;
			set = 1;
			break;
		case 'W' :
			rw = 3;
			set = 1;
			break;
		case '?' :
		default :
			usage();
		}

	if (ifs) {
		if (!filename || ns < 0)
			usage();
		if (ns == 0)
			return (changenatif(ifs, filename));
		else
			return (changestateif(ifs, filename));
	}

	if ((ns >= 0) || (lock >= 0)) {
		if (lock >= 0)
			devfd = opendevice(NULL);
		else if (ns >= 0) {
			if (ns == 1)
				devfd = opendevice(IPSTATE_NAME);
			else if (ns == 0)
				devfd = opendevice(IPNAT_NAME);
		}
		if (devfd == -1)
			exit(1);
	}

	if (lock >= 0)
		err = setlock(devfd, lock);
	else if (rw >= 0) {
		if (rw & 1) {	/* WRITE */
			if (rw & 2)
				err = writeall(dirname);
			else {
				if (ns == 0)
					err = writenat(devfd, filename);
				else if (ns == 1)
					err = writestate(devfd, filename);
			}
		} else {
			if (rw & 2)
				err = readall(dirname);
			else {
				if (ns == 0)
					err = readnat(devfd, filename);
				else if (ns == 1)
					err = readstate(devfd, filename);
			}
		}
	}
	return (err);
}


int opendevice(char *ipfdev)
{
	int fd = -1;

	if (opts & OPT_DONOTHING)
		return (-2);

	if (!ipfdev)
		ipfdev = IPL_NAME;

	if ((fd = open(ipfdev, O_RDWR)) == -1)
		if ((fd = open(ipfdev, O_RDONLY)) == -1)
			perror("open device");
	return (fd);
}


void closedevice(int fd)
{
	close(fd);
}


int setlock(int fd, int lock)
{
	if (opts & OPT_VERBOSE)
		printf("Turn lock %s\n", lock ? "on" : "off");
	if (!(opts & OPT_DONOTHING)) {
		if (ioctl(fd, SIOCSTLCK, &lock) == -1) {
			perror("SIOCSTLCK");
			return (1);
		}
		if (opts & OPT_VERBOSE)
			printf("Lock now %s\n", lock ? "on" : "off");
	}
	return (0);
}


int writestate(int fd, char *file)
{
	ipstate_save_t ips, *ipsp;
	ipfobj_t obj;
	int wfd = -1;

	if (!file)
		file = IPF_STATEFILE;

	wfd = open(file, O_WRONLY|O_TRUNC|O_CREAT, 0600);
	if (wfd == -1) {
		fprintf(stderr, "%s ", file);
		perror("state:open");
		return (1);
	}

	ipsp = &ips;
	bzero((char *)&obj, sizeof(obj));
	bzero((char *)ipsp, sizeof(ips));

	obj.ipfo_rev = IPFILTER_VERSION;
	obj.ipfo_size = sizeof(*ipsp);
	obj.ipfo_type = IPFOBJ_STATESAVE;
	obj.ipfo_ptr = ipsp;

	do {

		if (opts & OPT_VERBOSE)
			printf("Getting state from addr %p\n", ips.ips_next);
		if (ioctl(fd, SIOCSTGET, &obj)) {
			if (errno == ENOENT)
				break;
			perror("state:SIOCSTGET");
			close(wfd);
			return (1);
		}
		if (opts & OPT_VERBOSE)
			printf("Got state next %p\n", ips.ips_next);
		if (write(wfd, ipsp, sizeof(ips)) != sizeof(ips)) {
			perror("state:write");
			close(wfd);
			return (1);
		}
	} while (ips.ips_next != NULL);
	close(wfd);

	return (0);
}


int readstate(int fd, char *file)
{
	ipstate_save_t ips, *is, *ipshead = NULL, *is1, *ipstail = NULL;
	int sfd = -1, i;
	ipfobj_t obj;

	if (!file)
		file = IPF_STATEFILE;

	sfd = open(file, O_RDONLY, 0600);
	if (sfd == -1) {
		fprintf(stderr, "%s ", file);
		perror("open");
		return (1);
	}

	bzero((char *)&ips, sizeof(ips));

	/*
	 * 1. Read all state information in.
	 */
	do {
		i = read(sfd, &ips, sizeof(ips));
		if (i == -1) {
			perror("read");
			goto freeipshead;
		}
		if (i == 0)
			break;
		if (i != sizeof(ips)) {
			fprintf(stderr, "state:incomplete read: %d != %d\n",
				i, (int)sizeof(ips));
			goto freeipshead;
		}
		is = (ipstate_save_t *)malloc(sizeof(*is));
		if (is == NULL) {
			fprintf(stderr, "malloc failed\n");
			goto freeipshead;
		}

		bcopy((char *)&ips, (char *)is, sizeof(ips));

		/*
		 * Check to see if this is the first state entry that will
		 * reference a particular rule and if so, flag it as such
		 * else just adjust the rule pointer to become a pointer to
		 * the other.  We do this so we have a means later for tracking
		 * who is referencing us when we get back the real pointer
		 * in is_rule after doing the ioctl.
		 */
		for (is1 = ipshead; is1 != NULL; is1 = is1->ips_next)
			if (is1->ips_rule == is->ips_rule)
				break;
		if (is1 == NULL)
			is->ips_is.is_flags |= SI_NEWFR;
		else
			is->ips_rule = (void *)&is1->ips_rule;

		/*
		 * Use a tail-queue type list (add things to the end)..
		 */
		is->ips_next = NULL;
		if (!ipshead)
			ipshead = is;
		if (ipstail)
			ipstail->ips_next = is;
		ipstail = is;
	} while (1);

	close(sfd);

	obj.ipfo_rev = IPFILTER_VERSION;
	obj.ipfo_size = sizeof(*is);
	obj.ipfo_type = IPFOBJ_STATESAVE;

	while ((is = ipshead) != NULL) {
		if (opts & OPT_VERBOSE)
			printf("Loading new state table entry\n");
		if (is->ips_is.is_flags & SI_NEWFR) {
			if (opts & OPT_VERBOSE)
				printf("Loading new filter rule\n");
		}

		obj.ipfo_ptr = is;
		if (!(opts & OPT_DONOTHING))
			if (ioctl(fd, SIOCSTPUT, &obj)) {
				perror("SIOCSTPUT");
				goto freeipshead;
			}

		if (is->ips_is.is_flags & SI_NEWFR) {
			if (opts & OPT_VERBOSE)
				printf("Real rule addr %p\n", is->ips_rule);
			for (is1 = is->ips_next; is1; is1 = is1->ips_next)
				if (is1->ips_rule == (frentry_t *)&is->ips_rule)
					is1->ips_rule = is->ips_rule;
		}

		ipshead = is->ips_next;
		free(is);
	}

	return (0);

freeipshead:
	while ((is = ipshead) != NULL) {
		ipshead = is->ips_next;
		free(is);
	}
	if (sfd != -1)
		close(sfd);
	return (1);
}


int readnat(int fd, char *file)
{
	nat_save_t ipn, *in, *ipnhead = NULL, *in1, *ipntail = NULL;
	ipfobj_t obj;
	int nfd, i;
	nat_t *nat;
	char *s;
	int n;

	nfd = -1;
	in = NULL;
	ipnhead = NULL;
	ipntail = NULL;

	if (!file)
		file = IPF_NATFILE;

	nfd = open(file, O_RDONLY);
	if (nfd == -1) {
		fprintf(stderr, "%s ", file);
		perror("nat:open");
		return (1);
	}

	bzero((char *)&ipn, sizeof(ipn));

	/*
	 * 1. Read all state information in.
	 */
	do {
		i = read(nfd, &ipn, sizeof(ipn));
		if (i == -1) {
			perror("read");
			goto freenathead;
		}
		if (i == 0)
			break;
		if (i != sizeof(ipn)) {
			fprintf(stderr, "nat:incomplete read: %d != %d\n",
				i, (int)sizeof(ipn));
			goto freenathead;
		}

		in = (nat_save_t *)malloc(ipn.ipn_dsize);
		if (in == NULL) {
			fprintf(stderr, "nat:cannot malloc nat save atruct\n");
			goto freenathead;
		}

		if (ipn.ipn_dsize > sizeof(ipn)) {
			n = ipn.ipn_dsize - sizeof(ipn);
			if (n > 0) {
				s = in->ipn_data + sizeof(in->ipn_data);
 				i = read(nfd, s, n);
				if (i == 0)
					break;
				if (i != n) {
					fprintf(stderr,
					    "nat:incomplete read: %d != %d\n",
					    i, n);
					goto freenathead;
				}
			}
		}
		bcopy((char *)&ipn, (char *)in, sizeof(ipn));

		/*
		 * Check to see if this is the first NAT entry that will
		 * reference a particular rule and if so, flag it as such
		 * else just adjust the rule pointer to become a pointer to
		 * the other.  We do this so we have a means later for tracking
		 * who is referencing us when we get back the real pointer
		 * in is_rule after doing the ioctl.
		 */
		nat = &in->ipn_nat;
		if (nat->nat_fr != NULL) {
			for (in1 = ipnhead; in1 != NULL; in1 = in1->ipn_next)
				if (in1->ipn_rule == nat->nat_fr)
					break;
			if (in1 == NULL)
				nat->nat_flags |= SI_NEWFR;
			else
				nat->nat_fr = &in1->ipn_fr;
		}

		/*
		 * Use a tail-queue type list (add things to the end)..
		 */
		in->ipn_next = NULL;
		if (!ipnhead)
			ipnhead = in;
		if (ipntail)
			ipntail->ipn_next = in;
		ipntail = in;
	} while (1);

	close(nfd);
	nfd = -1;

	obj.ipfo_rev = IPFILTER_VERSION;
	obj.ipfo_type = IPFOBJ_NATSAVE;

	while ((in = ipnhead) != NULL) {
		if (opts & OPT_VERBOSE)
			printf("Loading new NAT table entry\n");
		nat = &in->ipn_nat;
		if (nat->nat_flags & SI_NEWFR) {
			if (opts & OPT_VERBOSE)
				printf("Loading new filter rule\n");
		}

		obj.ipfo_ptr = in;
		obj.ipfo_size = in->ipn_dsize;
		if (!(opts & OPT_DONOTHING))
			if (ioctl(fd, SIOCSTPUT, &obj)) {
				fprintf(stderr, "in=%p:", in);
				perror("SIOCSTPUT");
				return (1);
			}

		if (nat->nat_flags & SI_NEWFR) {
			if (opts & OPT_VERBOSE)
				printf("Real rule addr %p\n", nat->nat_fr);
			for (in1 = in->ipn_next; in1; in1 = in1->ipn_next)
				if (in1->ipn_rule == &in->ipn_fr)
					in1->ipn_rule = nat->nat_fr;
		}

		ipnhead = in->ipn_next;
		free(in);
	}

	return (0);

freenathead:
	while ((in = ipnhead) != NULL) {
		ipnhead = in->ipn_next;
		free(in);
	}
	if (nfd != -1)
		close(nfd);
	return (1);
}


int writenat(int fd, char *file)
{
	nat_save_t *ipnp = NULL, *next = NULL;
	ipfobj_t obj;
	int nfd = -1;
	natget_t ng;

	if (!file)
		file = IPF_NATFILE;

	nfd = open(file, O_WRONLY|O_TRUNC|O_CREAT, 0600);
	if (nfd == -1) {
		fprintf(stderr, "%s ", file);
		perror("nat:open");
		return (1);
	}

	obj.ipfo_rev = IPFILTER_VERSION;
	obj.ipfo_type = IPFOBJ_NATSAVE;

	do {
		if (opts & OPT_VERBOSE)
			printf("Getting nat from addr %p\n", ipnp);
		ng.ng_ptr = next;
		ng.ng_sz = 0;
		if (ioctl(fd, SIOCSTGSZ, &ng)) {
			perror("nat:SIOCSTGSZ");
			close(nfd);
			if (ipnp != NULL)
				free(ipnp);
			return (1);
		}

		if (opts & OPT_VERBOSE)
			printf("NAT size %d from %p\n", ng.ng_sz, ng.ng_ptr);

		if (ng.ng_sz == 0)
			break;

		if (!ipnp)
			ipnp = malloc(ng.ng_sz);
		else
			ipnp = realloc((char *)ipnp, ng.ng_sz);
		if (!ipnp) {
			fprintf(stderr,
				"malloc for %d bytes failed\n", ng.ng_sz);
			break;
		}

		bzero((char *)ipnp, ng.ng_sz);
		obj.ipfo_size = ng.ng_sz;
		obj.ipfo_ptr = ipnp;
		ipnp->ipn_dsize = ng.ng_sz;
		ipnp->ipn_next = next;
		if (ioctl(fd, SIOCSTGET, &obj)) {
			if (errno == ENOENT)
				break;
			perror("nat:SIOCSTGET");
			close(nfd);
			free(ipnp);
			return (1);
		}

		if (opts & OPT_VERBOSE)
			printf("Got nat next %p ipn_dsize %d ng_sz %d\n",
				ipnp->ipn_next, ipnp->ipn_dsize, ng.ng_sz);
		if (write(nfd, ipnp, ipnp->ipn_dsize) != ipnp->ipn_dsize) {
			perror("nat:write");
			close(nfd);
			free(ipnp);
			return (1);
		}
		next = ipnp->ipn_next;
	} while (ipnp && next);
	if (ipnp != NULL)
		free(ipnp);
	close(nfd);

	return (0);
}


int writeall(char *dirname)
{
	int fd, devfd;

	if (!dirname)
		dirname = IPF_SAVEDIR;

	if (chdir(dirname)) {
		fprintf(stderr, "IPF_SAVEDIR=%s: ", dirname);
		perror("chdir(IPF_SAVEDIR)");
		return (1);
	}

	fd = opendevice(NULL);
	if (fd == -1)
		return (1);
	if (setlock(fd, 1)) {
		close(fd);
		return (1);
	}

	devfd = opendevice(IPSTATE_NAME);
	if (devfd == -1)
		goto bad;
	if (writestate(devfd, NULL))
		goto bad;
	close(devfd);

	devfd = opendevice(IPNAT_NAME);
	if (devfd == -1)
		goto bad;
	if (writenat(devfd, NULL))
		goto bad;
	close(devfd);

	if (setlock(fd, 0)) {
		close(fd);
		return (1);
	}

	close(fd);
	return (0);

bad:
	setlock(fd, 0);
	close(fd);
	return (1);
}


int readall(char *dirname)
{
	int fd, devfd;

	if (!dirname)
		dirname = IPF_SAVEDIR;

	if (chdir(dirname)) {
		perror("chdir(IPF_SAVEDIR)");
		return (1);
	}

	fd = opendevice(NULL);
	if (fd == -1)
		return (1);
	if (setlock(fd, 1)) {
		close(fd);
		return (1);
	}

	devfd = opendevice(IPSTATE_NAME);
	if (devfd == -1)
		return (1);
	if (readstate(devfd, NULL))
		return (1);
	close(devfd);

	devfd = opendevice(IPNAT_NAME);
	if (devfd == -1)
		return (1);
	if (readnat(devfd, NULL))
		return (1);
	close(devfd);

	if (setlock(fd, 0)) {
		close(fd);
		return (1);
	}

	return (0);
}