/*

 * Copyright (c) 2005 Evgeniy Polyakov <johnpol@2ka.mxt.ru>

 * 

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

 */

#include <sys/types.h>

#include <sys/socket.h>

#include <sys/poll.h>

#include <sys/time.h>

#include <arpa/inet.h>

#include <ctype.h>

#include <errno.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <stdarg.h>

#include <time.h>

#include <unistd.h>

#include <netinet/ip.h>

#include <netinet/tcp.h>

#include <linux/connector.h>

#include <linux/types.h>

#include <linux/netlink.h>

#include <linux/rtnetlink.h>

#include <linux/unistd.h>

#include <libnfnetlink/libnfnetlink.h>

#include <linux/netfilter/nfnetlink.h>

#include <linux/netfilter/xt_osf.h>

#define OPTDEL			','

#define OSFPDEL 		':'

#define MAXOPTSTRLEN		128

#ifndef NIPQUAD

#define NIPQUAD(addr) \

	((unsigned char *)&addr)[0], \

	((unsigned char *)&addr)[1], \

	((unsigned char *)&addr)[2], \

	((unsigned char *)&addr)[3]

#endif

static struct nfnl_handle *nfnlh;

static struct nfnl_subsys_handle *nfnlssh;

static struct xt_osf_opt IANA_opts[] = {

	{ .kind = 0, .length = 1,},

	{ .kind=1, .length=1,},

	{ .kind=2, .length=4,},

	{ .kind=3, .length=3,},

	{ .kind=4, .length=2,},

	{ .kind=5, .length=1,},		/* SACK length is not defined */

	{ .kind=6, .length=6,},

	{ .kind=7, .length=6,},

	{ .kind=8, .length=10,},

	{ .kind=9, .length=2,},

	{ .kind=10, .length=3,},

	{ .kind=11, .length=1,},		/* CC: Suppose 1 */

	{ .kind=12, .length=1,},		/* the same */

	{ .kind=13, .length=1,},		/* and here too */

	{ .kind=14, .length=3,},

	{ .kind=15, .length=1,},		/* TCP Alternate Checksum Data. Length is not defined */

	{ .kind=16, .length=1,},

	{ .kind=17, .length=1,},

	{ .kind=18, .length=3,},

	{ .kind=19, .length=18,},

	{ .kind=20, .length=1,},

	{ .kind=21, .length=1,},

	{ .kind=22, .length=1,},

	{ .kind=23, .length=1,},

	{ .kind=24, .length=1,},

	{ .kind=25, .length=1,},

	{ .kind=26, .length=1,},

};

static FILE *osf_log_stream;

static void uloga(const char *f, ...)

{

	va_list ap;

	if (!osf_log_stream)

		osf_log_stream = stdout;

	va_start(ap, f);

	vfprintf(osf_log_stream, f, ap);

	va_end(ap);

	fflush(osf_log_stream);

}

static void ulog(const char *f, ...)

{

	char str[64];

	struct tm tm;

	struct timeval tv;

	va_list ap;

	if (!osf_log_stream)

		osf_log_stream = stdout;

	gettimeofday(&tv, NULL);

	localtime_r((time_t *)&tv.tv_sec, &tm;;

	strftime(str, sizeof(str), "%F %R:%S", &tm;;

	fprintf(osf_log_stream, "%s.%lu %ld ", str, tv.tv_usec, syscall(__NR_gettid));

	va_start(ap, f);

	vfprintf(osf_log_stream, f, ap);

	va_end(ap);

	fflush(osf_log_stream);

}

#define ulog_err(f, a...) uloga(f ": %s [%d].\n", ##a, strerror(errno), errno)

static char *xt_osf_strchr(char *ptr, char c)

{

	char *tmp;

	tmp = strchr(ptr, c);

	if (tmp)

		*tmp = '\0';

	while (tmp && isspace(*(tmp + 1)))

		tmp++;

	return tmp;

}

static void xt_osf_parse_opt(struct xt_osf_opt *opt, __u16 *optnum, char *obuf, int olen)

{

	int i, op;

	char *ptr, wc;

	unsigned long val;

	ptr = &obuf[0];

	i = 0;

	while (ptr != NULL && i < olen && *ptr != 0) {

		val = 0;

		wc = OSF_WSS_PLAIN;

		switch (obuf[i]) {

		case 'N':

			op = OSFOPT_NOP;

			ptr = xt_osf_strchr(&obuf[i], OPTDEL);

			if (ptr) {

				*ptr = '\0';

				ptr++;

				i += (int)(ptr - &obuf[i]);

			} else

				i++;

			break;

		case 'S':

			op = OSFOPT_SACKP;

			ptr = xt_osf_strchr(&obuf[i], OPTDEL);

			if (ptr) {

				*ptr = '\0';

				ptr++;

				i += (int)(ptr - &obuf[i]);

			} else

				i++;

			break;

		case 'T':

			op = OSFOPT_TS;

			ptr = xt_osf_strchr(&obuf[i], OPTDEL);

			if (ptr) {

				*ptr = '\0';

				ptr++;

				i += (int)(ptr - &obuf[i]);

			} else

				i++;

			break;

		case 'W':

			op = OSFOPT_WSO;

			ptr = xt_osf_strchr(&obuf[i], OPTDEL);

			if (ptr) {

				switch (obuf[i + 1]) {

				case '%':

					wc = OSF_WSS_MODULO;

					break;

				case 'S':

					wc = OSF_WSS_MSS;

					break;

				case 'T':

					wc = OSF_WSS_MTU;

					break;

				default:

					wc = OSF_WSS_PLAIN;

					break;

				}

				*ptr = '\0';

				ptr++;

				if (wc)

					val = strtoul(&obuf[i + 2], NULL, 10);

				else

					val = strtoul(&obuf[i + 1], NULL, 10);

				i += (int)(ptr - &obuf[i]);

			} else

				i++;

			break;

		case 'M':

			op = OSFOPT_MSS;

			ptr = xt_osf_strchr(&obuf[i], OPTDEL);

			if (ptr) {

				if (obuf[i + 1] == '%')

					wc = OSF_WSS_MODULO;

				*ptr = '\0';

				ptr++;

				if (wc)

					val = strtoul(&obuf[i + 2], NULL, 10);

				else

					val = strtoul(&obuf[i + 1], NULL, 10);

				i += (int)(ptr - &obuf[i]);

			} else

				i++;

			break;

		case 'E':

			op = OSFOPT_EOL;

			ptr = xt_osf_strchr(&obuf[i], OPTDEL);

			if (ptr) {

				*ptr = '\0';

				ptr++;

				i += (int)(ptr - &obuf[i]);

			} else

				i++;

			break;

		default:

			op = OSFOPT_EMPTY;

			ptr = xt_osf_strchr(&obuf[i], OPTDEL);

			if (ptr) {

				ptr++;

				i += (int)(ptr - &obuf[i]);

			} else

				i++;

			break;

		}

		if (op != OSFOPT_EMPTY) {

			opt[*optnum].kind = IANA_opts[op].kind;

			opt[*optnum].length = IANA_opts[op].length;

			opt[*optnum].wc.wc = wc;

			opt[*optnum].wc.val = val;

			(*optnum)++;

		}

	}

}

static int osf_load_line(char *buffer, int len, int del)

{

	int i, cnt = 0;

	char obuf[MAXOPTSTRLEN];

	struct xt_osf_user_finger f;

	char *pbeg, *pend;

	char buf[NFNL_HEADER_LEN + NFA_LENGTH(sizeof(struct xt_osf_user_finger))];

	struct nlmsghdr *nmh = (struct nlmsghdr *) buf;

	memset(&f, 0, sizeof(struct xt_osf_user_finger));

	ulog("Loading '%s'.\n", buffer);

	for (i = 0; i < len && buffer[i] != '\0'; ++i) {

		if (buffer[i] == ':')

			cnt++;

	}

	if (cnt != 8) {

		ulog("Wrong input line '%s': cnt: %d, must be 8, i: %d, must be %d.\n", buffer, cnt, i, len);

		return -EINVAL;

	}

	memset(obuf, 0, sizeof(obuf));

	pbeg = buffer;

	pend = xt_osf_strchr(pbeg, OSFPDEL);

	if (pend) {

		*pend = '\0';

		if (pbeg[0] == 'S') {

			f.wss.wc = OSF_WSS_MSS;

			if (pbeg[1] == '%')

				f.wss.val = strtoul(&pbeg[2], NULL, 10);

			else if (pbeg[1] == '*')

				f.wss.val = 0;

			else

				f.wss.val = strtoul(&pbeg[1], NULL, 10);

		} else if (pbeg[0] == 'T') {

			f.wss.wc = OSF_WSS_MTU;

			if (pbeg[1] == '%')

				f.wss.val = strtoul(&pbeg[2], NULL, 10);

			else if (pbeg[1] == '*')

				f.wss.val = 0;

			else

				f.wss.val = strtoul(&pbeg[1], NULL, 10);

		} else if (pbeg[0] == '%') {

			f.wss.wc = OSF_WSS_MODULO;

			f.wss.val = strtoul(&pbeg[1], NULL, 10);

		} else if (isdigit(pbeg[0])) {

			f.wss.wc = OSF_WSS_PLAIN;

			f.wss.val = strtoul(&pbeg[0], NULL, 10);

		}

		pbeg = pend + 1;

	}

	pend = xt_osf_strchr(pbeg, OSFPDEL);

	if (pend) {

		*pend = '\0';

		f.ttl = strtoul(pbeg, NULL, 10);

		pbeg = pend + 1;

	}

	pend = xt_osf_strchr(pbeg, OSFPDEL);

	if (pend) {

		*pend = '\0';

		f.df = strtoul(pbeg, NULL, 10);

		pbeg = pend + 1;

	}

	pend = xt_osf_strchr(pbeg, OSFPDEL);

	if (pend) {

		*pend = '\0';

		f.ss = strtoul(pbeg, NULL, 10);

		pbeg = pend + 1;

	}

	pend = xt_osf_strchr(pbeg, OSFPDEL);

	if (pend) {

		*pend = '\0';

		i = sizeof(obuf);

		snprintf(obuf, i, "%.*s,", i - 2, pbeg);

		pbeg = pend + 1;

	}

	pend = xt_osf_strchr(pbeg, OSFPDEL);

	if (pend) {

		*pend = '\0';

		i = sizeof(f.genre);

		if (pbeg[0] == '@' || pbeg[0] == '*')

			pbeg++;

		snprintf(f.genre, i, "%.*s", i - 1, pbeg);

		pbeg = pend + 1;

	}

	pend = xt_osf_strchr(pbeg, OSFPDEL);

	if (pend) {

		*pend = '\0';

		i = sizeof(f.version);

		snprintf(f.version, i, "%.*s", i - 1, pbeg);

		pbeg = pend + 1;

	}

	pend = xt_osf_strchr(pbeg, OSFPDEL);

	if (pend) {

		*pend = '\0';

		i = sizeof(f.subtype);

		snprintf(f.subtype, i, "%.*s", i - 1, pbeg);

	}

	xt_osf_parse_opt(f.opt, &f.opt_num, obuf, sizeof(obuf));

	memset(buf, 0, sizeof(buf));

	if (del)

		nfnl_fill_hdr(nfnlssh, nmh, 0, AF_UNSPEC, 0, OSF_MSG_REMOVE,

			      NLM_F_ACK | NLM_F_REQUEST);

	else

		nfnl_fill_hdr(nfnlssh, nmh, 0, AF_UNSPEC, 0, OSF_MSG_ADD,

			      NLM_F_ACK | NLM_F_REQUEST | NLM_F_CREATE);

	nfnl_addattr_l(nmh, sizeof(buf), OSF_ATTR_FINGER, &f, sizeof(struct xt_osf_user_finger));

	return nfnl_query(nfnlh, nmh);

}

static int osf_load_entries(char *path, int del)

{

	FILE *inf;

	int err = 0, lineno = 0;

	char buf[1024];

	inf = fopen(path, "r");

	if (!inf) {

		ulog_err("Failed to open file '%s'", path);

		return -1;

	}

	while(fgets(buf, sizeof(buf), inf)) {

		int len, rc;

		lineno++;

		if (buf[0] == '#' || buf[0] == '\n' || buf[0] == '\r')

			continue;

		len = strlen(buf) - 1;

		if (len <= 0)

			continue;

		buf[len] = '\0';

		rc = osf_load_line(buf, len, del);

		if (rc && (!del || errno != ENOENT)) {

			ulog_err("Failed to load line %d", lineno);

			err = rc;

		}

		memset(buf, 0, sizeof(buf));

	}

	fclose(inf);

	return err;

}

int main(int argc, char *argv[])

{

	int ch, del = 0, err;

	char *fingerprints = NULL;

	while ((ch = getopt(argc, argv, "f:dh")) != -1) {

		switch (ch) {

			case 'f':

				fingerprints = optarg;

				break;

			case 'd':

				del = 1;

				break;

			default:

				fprintf(stderr,

					"Usage: %s -f fingerprints [-d]\n",

					argv[0]);

				return -1;

		}

	}

	if (!fingerprints) {

		err = -ENOENT;

		ulog("Missing fingerprints file argument.\n");

		goto err_out_exit;

	}

	nfnlh = nfnl_open();

	if (!nfnlh) {

		err = -EINVAL;

		ulog_err("Failed to create nfnl handler");

		goto err_out_exit;

	}

#ifndef NFNL_SUBSYS_OSF

#define NFNL_SUBSYS_OSF	5

#endif

	nfnlssh = nfnl_subsys_open(nfnlh, NFNL_SUBSYS_OSF, OSF_MSG_MAX, 0);

	if (!nfnlssh) {

		err = -EINVAL;

		ulog_err("Faied to create nfnl subsystem");

		goto err_out_close;

	}

	err = osf_load_entries(fingerprints, del);

	if (err)

		goto err_out_close_subsys;

	nfnl_subsys_close(nfnlssh);

	nfnl_close(nfnlh);

	return 0;

err_out_close_subsys:

	nfnl_subsys_close(nfnlssh);

err_out_close:

	nfnl_close(nfnlh);

err_out_exit:

	return err;

}