xref: /openbmc/linux/net/netfilter/ipvs/ip_vs_ftp.c (revision daf47a7c)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * ip_vs_ftp.c: IPVS ftp application module
4  *
5  * Authors:	Wensong Zhang <wensong@linuxvirtualserver.org>
6  *
7  * Changes:
8  *
9  * Most code here is taken from ip_masq_ftp.c in kernel 2.2. The difference
10  * is that ip_vs_ftp module handles the reverse direction to ip_masq_ftp.
11  *
12  *		IP_MASQ_FTP ftp masquerading module
13  *
14  * Version:	@(#)ip_masq_ftp.c 0.04   02/05/96
15  *
16  * Author:	Wouter Gadeyne
17  */
18 
19 #define KMSG_COMPONENT "IPVS"
20 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
21 
22 #include <linux/module.h>
23 #include <linux/moduleparam.h>
24 #include <linux/kernel.h>
25 #include <linux/skbuff.h>
26 #include <linux/ctype.h>
27 #include <linux/inet.h>
28 #include <linux/in.h>
29 #include <linux/ip.h>
30 #include <linux/netfilter.h>
31 #include <net/netfilter/nf_conntrack.h>
32 #include <net/netfilter/nf_conntrack_expect.h>
33 #include <net/netfilter/nf_nat.h>
34 #include <net/netfilter/nf_nat_helper.h>
35 #include <linux/gfp.h>
36 #include <net/protocol.h>
37 #include <net/tcp.h>
38 #include <asm/unaligned.h>
39 
40 #include <net/ip_vs.h>
41 
42 
43 #define SERVER_STRING_PASV "227 "
44 #define CLIENT_STRING_PORT "PORT"
45 #define SERVER_STRING_EPSV "229 "
46 #define CLIENT_STRING_EPRT "EPRT"
47 
48 enum {
49 	IP_VS_FTP_ACTIVE = 0,
50 	IP_VS_FTP_PORT = 0,
51 	IP_VS_FTP_PASV,
52 	IP_VS_FTP_EPRT,
53 	IP_VS_FTP_EPSV,
54 };
55 
56 /*
57  * List of ports (up to IP_VS_APP_MAX_PORTS) to be handled by helper
58  * First port is set to the default port.
59  */
60 static unsigned int ports_count = 1;
61 static unsigned short ports[IP_VS_APP_MAX_PORTS] = {21, 0};
62 module_param_array(ports, ushort, &ports_count, 0444);
63 MODULE_PARM_DESC(ports, "Ports to monitor for FTP control commands");
64 
65 
ip_vs_ftp_data_ptr(struct sk_buff * skb,struct ip_vs_iphdr * ipvsh)66 static char *ip_vs_ftp_data_ptr(struct sk_buff *skb, struct ip_vs_iphdr *ipvsh)
67 {
68 	struct tcphdr *th = (struct tcphdr *)((char *)skb->data + ipvsh->len);
69 
70 	if ((th->doff << 2) < sizeof(struct tcphdr))
71 		return NULL;
72 
73 	return (char *)th + (th->doff << 2);
74 }
75 
76 static int
ip_vs_ftp_init_conn(struct ip_vs_app * app,struct ip_vs_conn * cp)77 ip_vs_ftp_init_conn(struct ip_vs_app *app, struct ip_vs_conn *cp)
78 {
79 	/* We use connection tracking for the command connection */
80 	cp->flags |= IP_VS_CONN_F_NFCT;
81 	return 0;
82 }
83 
84 
85 static int
ip_vs_ftp_done_conn(struct ip_vs_app * app,struct ip_vs_conn * cp)86 ip_vs_ftp_done_conn(struct ip_vs_app *app, struct ip_vs_conn *cp)
87 {
88 	return 0;
89 }
90 
91 
92 /* Get <addr,port> from the string "xxx.xxx.xxx.xxx,ppp,ppp", started
93  * with the "pattern". <addr,port> is in network order.
94  * Parse extended format depending on ext. In this case addr can be pre-set.
95  */
ip_vs_ftp_get_addrport(char * data,char * data_limit,const char * pattern,size_t plen,char skip,bool ext,int mode,union nf_inet_addr * addr,__be16 * port,__u16 af,char ** start,char ** end)96 static int ip_vs_ftp_get_addrport(char *data, char *data_limit,
97 				  const char *pattern, size_t plen,
98 				  char skip, bool ext, int mode,
99 				  union nf_inet_addr *addr, __be16 *port,
100 				  __u16 af, char **start, char **end)
101 {
102 	char *s, c;
103 	unsigned char p[6];
104 	char edelim;
105 	__u16 hport;
106 	int i = 0;
107 
108 	if (data_limit - data < plen) {
109 		/* check if there is partial match */
110 		if (strncasecmp(data, pattern, data_limit - data) == 0)
111 			return -1;
112 		else
113 			return 0;
114 	}
115 
116 	if (strncasecmp(data, pattern, plen) != 0) {
117 		return 0;
118 	}
119 	s = data + plen;
120 	if (skip) {
121 		bool found = false;
122 
123 		for (;; s++) {
124 			if (s == data_limit)
125 				return -1;
126 			if (!found) {
127 				/* "(" is optional for non-extended format,
128 				 * so catch the start of IPv4 address
129 				 */
130 				if (!ext && isdigit(*s))
131 					break;
132 				if (*s == skip)
133 					found = true;
134 			} else if (*s != skip) {
135 				break;
136 			}
137 		}
138 	}
139 	/* Old IPv4-only format? */
140 	if (!ext) {
141 		p[0] = 0;
142 		for (data = s; ; data++) {
143 			if (data == data_limit)
144 				return -1;
145 			c = *data;
146 			if (isdigit(c)) {
147 				p[i] = p[i]*10 + c - '0';
148 			} else if (c == ',' && i < 5) {
149 				i++;
150 				p[i] = 0;
151 			} else {
152 				/* unexpected character or terminator */
153 				break;
154 			}
155 		}
156 
157 		if (i != 5)
158 			return -1;
159 
160 		*start = s;
161 		*end = data;
162 		addr->ip = get_unaligned((__be32 *) p);
163 		*port = get_unaligned((__be16 *) (p + 4));
164 		return 1;
165 	}
166 	if (s == data_limit)
167 		return -1;
168 	*start = s;
169 	edelim = *s++;
170 	if (edelim < 33 || edelim > 126)
171 		return -1;
172 	if (s == data_limit)
173 		return -1;
174 	if (*s == edelim) {
175 		/* Address family is usually missing for EPSV response */
176 		if (mode != IP_VS_FTP_EPSV)
177 			return -1;
178 		s++;
179 		if (s == data_limit)
180 			return -1;
181 		/* Then address should be missing too */
182 		if (*s != edelim)
183 			return -1;
184 		/* Caller can pre-set addr, if needed */
185 		s++;
186 	} else {
187 		const char *ep;
188 
189 		/* We allow address only from same family */
190 		if (af == AF_INET6 && *s != '2')
191 			return -1;
192 		if (af == AF_INET && *s != '1')
193 			return -1;
194 		s++;
195 		if (s == data_limit)
196 			return -1;
197 		if (*s != edelim)
198 			return -1;
199 		s++;
200 		if (s == data_limit)
201 			return -1;
202 		if (af == AF_INET6) {
203 			if (in6_pton(s, data_limit - s, (u8 *)addr, edelim,
204 				     &ep) <= 0)
205 				return -1;
206 		} else {
207 			if (in4_pton(s, data_limit - s, (u8 *)addr, edelim,
208 				     &ep) <= 0)
209 				return -1;
210 		}
211 		s = (char *) ep;
212 		if (s == data_limit)
213 			return -1;
214 		if (*s != edelim)
215 			return -1;
216 		s++;
217 	}
218 	for (hport = 0; ; s++)
219 	{
220 		if (s == data_limit)
221 			return -1;
222 		if (!isdigit(*s))
223 			break;
224 		hport = hport * 10 + *s - '0';
225 	}
226 	if (s == data_limit || !hport || *s != edelim)
227 		return -1;
228 	s++;
229 	*end = s;
230 	*port = htons(hport);
231 	return 1;
232 }
233 
234 /* Look at outgoing ftp packets to catch the response to a PASV/EPSV command
235  * from the server (inside-to-outside).
236  * When we see one, we build a connection entry with the client address,
237  * client port 0 (unknown at the moment), the server address and the
238  * server port.  Mark the current connection entry as a control channel
239  * of the new entry. All this work is just to make the data connection
240  * can be scheduled to the right server later.
241  *
242  * The outgoing packet should be something like
243  *   "227 Entering Passive Mode (xxx,xxx,xxx,xxx,ppp,ppp)".
244  * xxx,xxx,xxx,xxx is the server address, ppp,ppp is the server port number.
245  * The extended format for EPSV response provides usually only port:
246  *   "229 Entering Extended Passive Mode (|||ppp|)"
247  */
ip_vs_ftp_out(struct ip_vs_app * app,struct ip_vs_conn * cp,struct sk_buff * skb,int * diff,struct ip_vs_iphdr * ipvsh)248 static int ip_vs_ftp_out(struct ip_vs_app *app, struct ip_vs_conn *cp,
249 			 struct sk_buff *skb, int *diff,
250 			 struct ip_vs_iphdr *ipvsh)
251 {
252 	char *data, *data_limit;
253 	char *start, *end;
254 	union nf_inet_addr from;
255 	__be16 port;
256 	struct ip_vs_conn *n_cp;
257 	char buf[24];		/* xxx.xxx.xxx.xxx,ppp,ppp\000 */
258 	unsigned int buf_len;
259 	int ret = 0;
260 	enum ip_conntrack_info ctinfo;
261 	struct nf_conn *ct;
262 
263 	*diff = 0;
264 
265 	/* Only useful for established sessions */
266 	if (cp->state != IP_VS_TCP_S_ESTABLISHED)
267 		return 1;
268 
269 	/* Linear packets are much easier to deal with. */
270 	if (skb_ensure_writable(skb, skb->len))
271 		return 0;
272 
273 	if (cp->app_data == (void *) IP_VS_FTP_PASV) {
274 		data = ip_vs_ftp_data_ptr(skb, ipvsh);
275 		data_limit = skb_tail_pointer(skb);
276 
277 		if (!data || data >= data_limit)
278 			return 1;
279 
280 		if (ip_vs_ftp_get_addrport(data, data_limit,
281 					   SERVER_STRING_PASV,
282 					   sizeof(SERVER_STRING_PASV)-1,
283 					   '(', false, IP_VS_FTP_PASV,
284 					   &from, &port, cp->af,
285 					   &start, &end) != 1)
286 			return 1;
287 
288 		IP_VS_DBG(7, "PASV response (%pI4:%u) -> %pI4:%u detected\n",
289 			  &from.ip, ntohs(port), &cp->caddr.ip, 0);
290 	} else if (cp->app_data == (void *) IP_VS_FTP_EPSV) {
291 		data = ip_vs_ftp_data_ptr(skb, ipvsh);
292 		data_limit = skb_tail_pointer(skb);
293 
294 		if (!data || data >= data_limit)
295 			return 1;
296 
297 		/* Usually, data address is not specified but
298 		 * we support different address, so pre-set it.
299 		 */
300 		from = cp->daddr;
301 		if (ip_vs_ftp_get_addrport(data, data_limit,
302 					   SERVER_STRING_EPSV,
303 					   sizeof(SERVER_STRING_EPSV)-1,
304 					   '(', true, IP_VS_FTP_EPSV,
305 					   &from, &port, cp->af,
306 					   &start, &end) != 1)
307 			return 1;
308 
309 		IP_VS_DBG_BUF(7, "EPSV response (%s:%u) -> %s:%u detected\n",
310 			      IP_VS_DBG_ADDR(cp->af, &from), ntohs(port),
311 			      IP_VS_DBG_ADDR(cp->af, &cp->caddr), 0);
312 	} else {
313 		return 1;
314 	}
315 
316 	/* Now update or create a connection entry for it */
317 	{
318 		struct ip_vs_conn_param p;
319 
320 		ip_vs_conn_fill_param(cp->ipvs, cp->af,
321 				      ipvsh->protocol, &from, port,
322 				      &cp->caddr, 0, &p);
323 		n_cp = ip_vs_conn_out_get(&p);
324 	}
325 	if (!n_cp) {
326 		struct ip_vs_conn_param p;
327 
328 		ip_vs_conn_fill_param(cp->ipvs,
329 				      cp->af, ipvsh->protocol, &cp->caddr,
330 				      0, &cp->vaddr, port, &p);
331 		n_cp = ip_vs_conn_new(&p, cp->af, &from, port,
332 				      IP_VS_CONN_F_NO_CPORT |
333 				      IP_VS_CONN_F_NFCT,
334 				      cp->dest, skb->mark);
335 		if (!n_cp)
336 			return 0;
337 
338 		/* add its controller */
339 		ip_vs_control_add(n_cp, cp);
340 	}
341 
342 	/* Replace the old passive address with the new one */
343 	if (cp->app_data == (void *) IP_VS_FTP_PASV) {
344 		from.ip = n_cp->vaddr.ip;
345 		port = n_cp->vport;
346 		snprintf(buf, sizeof(buf), "%u,%u,%u,%u,%u,%u",
347 			 ((unsigned char *)&from.ip)[0],
348 			 ((unsigned char *)&from.ip)[1],
349 			 ((unsigned char *)&from.ip)[2],
350 			 ((unsigned char *)&from.ip)[3],
351 			 ntohs(port) >> 8,
352 			 ntohs(port) & 0xFF);
353 	} else if (cp->app_data == (void *) IP_VS_FTP_EPSV) {
354 		from = n_cp->vaddr;
355 		port = n_cp->vport;
356 		/* Only port, client will use VIP for the data connection */
357 		snprintf(buf, sizeof(buf), "|||%u|",
358 			 ntohs(port));
359 	} else {
360 		*buf = 0;
361 	}
362 	buf_len = strlen(buf);
363 
364 	ct = nf_ct_get(skb, &ctinfo);
365 	if (ct) {
366 		bool mangled;
367 
368 		/* If mangling fails this function will return 0
369 		 * which will cause the packet to be dropped.
370 		 * Mangling can only fail under memory pressure,
371 		 * hopefully it will succeed on the retransmitted
372 		 * packet.
373 		 */
374 		mangled = nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
375 						   ipvsh->len,
376 						   start - data,
377 						   end - start,
378 						   buf, buf_len);
379 		if (mangled) {
380 			ip_vs_nfct_expect_related(skb, ct, n_cp,
381 						  ipvsh->protocol, 0, 0);
382 			if (skb->ip_summed == CHECKSUM_COMPLETE)
383 				skb->ip_summed = CHECKSUM_UNNECESSARY;
384 			/* csum is updated */
385 			ret = 1;
386 		}
387 	}
388 
389 	/* Not setting 'diff' is intentional, otherwise the sequence
390 	 * would be adjusted twice.
391 	 */
392 
393 	cp->app_data = (void *) IP_VS_FTP_ACTIVE;
394 	ip_vs_tcp_conn_listen(n_cp);
395 	ip_vs_conn_put(n_cp);
396 	return ret;
397 }
398 
399 
400 /* Look at incoming ftp packets to catch the PASV/PORT/EPRT/EPSV command
401  * (outside-to-inside).
402  *
403  * The incoming packet having the PORT command should be something like
404  *      "PORT xxx,xxx,xxx,xxx,ppp,ppp\n".
405  * xxx,xxx,xxx,xxx is the client address, ppp,ppp is the client port number.
406  * In this case, we create a connection entry using the client address and
407  * port, so that the active ftp data connection from the server can reach
408  * the client.
409  * Extended format:
410  *	"EPSV\r\n" when client requests server address from same family
411  *	"EPSV 1\r\n" when client requests IPv4 server address
412  *	"EPSV 2\r\n" when client requests IPv6 server address
413  *	"EPSV ALL\r\n" - not supported
414  *	EPRT with specified delimiter (ASCII 33..126), "|" by default:
415  *	"EPRT |1|IPv4ADDR|PORT|\r\n" when client provides IPv4 addrport
416  *	"EPRT |2|IPv6ADDR|PORT|\r\n" when client provides IPv6 addrport
417  */
ip_vs_ftp_in(struct ip_vs_app * app,struct ip_vs_conn * cp,struct sk_buff * skb,int * diff,struct ip_vs_iphdr * ipvsh)418 static int ip_vs_ftp_in(struct ip_vs_app *app, struct ip_vs_conn *cp,
419 			struct sk_buff *skb, int *diff,
420 			struct ip_vs_iphdr *ipvsh)
421 {
422 	char *data, *data_start, *data_limit;
423 	char *start, *end;
424 	union nf_inet_addr to;
425 	__be16 port;
426 	struct ip_vs_conn *n_cp;
427 
428 	/* no diff required for incoming packets */
429 	*diff = 0;
430 
431 	/* Only useful for established sessions */
432 	if (cp->state != IP_VS_TCP_S_ESTABLISHED)
433 		return 1;
434 
435 	/* Linear packets are much easier to deal with. */
436 	if (skb_ensure_writable(skb, skb->len))
437 		return 0;
438 
439 	data = data_start = ip_vs_ftp_data_ptr(skb, ipvsh);
440 	data_limit = skb_tail_pointer(skb);
441 	if (!data || data >= data_limit)
442 		return 1;
443 
444 	while (data <= data_limit - 6) {
445 		if (cp->af == AF_INET &&
446 		    strncasecmp(data, "PASV\r\n", 6) == 0) {
447 			/* Passive mode on */
448 			IP_VS_DBG(7, "got PASV at %td of %td\n",
449 				  data - data_start,
450 				  data_limit - data_start);
451 			cp->app_data = (void *) IP_VS_FTP_PASV;
452 			return 1;
453 		}
454 
455 		/* EPSV or EPSV<space><net-prt> */
456 		if (strncasecmp(data, "EPSV", 4) == 0 &&
457 		    (data[4] == ' ' || data[4] == '\r')) {
458 			if (data[4] == ' ') {
459 				char proto = data[5];
460 
461 				if (data > data_limit - 7 || data[6] != '\r')
462 					return 1;
463 
464 #ifdef CONFIG_IP_VS_IPV6
465 				if (cp->af == AF_INET6 && proto == '2') {
466 				} else
467 #endif
468 				if (cp->af == AF_INET && proto == '1') {
469 				} else {
470 					return 1;
471 				}
472 			}
473 			/* Extended Passive mode on */
474 			IP_VS_DBG(7, "got EPSV at %td of %td\n",
475 				  data - data_start,
476 				  data_limit - data_start);
477 			cp->app_data = (void *) IP_VS_FTP_EPSV;
478 			return 1;
479 		}
480 
481 		data++;
482 	}
483 
484 	/*
485 	 * To support virtual FTP server, the scenerio is as follows:
486 	 *       FTP client ----> Load Balancer ----> FTP server
487 	 * First detect the port number in the application data,
488 	 * then create a new connection entry for the coming data
489 	 * connection.
490 	 */
491 	if (cp->af == AF_INET &&
492 	    ip_vs_ftp_get_addrport(data_start, data_limit,
493 				   CLIENT_STRING_PORT,
494 				   sizeof(CLIENT_STRING_PORT)-1,
495 				   ' ', false, IP_VS_FTP_PORT,
496 				   &to, &port, cp->af,
497 				   &start, &end) == 1) {
498 
499 		IP_VS_DBG(7, "PORT %pI4:%u detected\n", &to.ip, ntohs(port));
500 
501 		/* Now update or create a connection entry for it */
502 		IP_VS_DBG(7, "protocol %s %pI4:%u %pI4:%u\n",
503 			  ip_vs_proto_name(ipvsh->protocol),
504 			  &to.ip, ntohs(port), &cp->vaddr.ip,
505 			  ntohs(cp->vport)-1);
506 	} else if (ip_vs_ftp_get_addrport(data_start, data_limit,
507 					  CLIENT_STRING_EPRT,
508 					  sizeof(CLIENT_STRING_EPRT)-1,
509 					  ' ', true, IP_VS_FTP_EPRT,
510 					  &to, &port, cp->af,
511 					  &start, &end) == 1) {
512 
513 		IP_VS_DBG_BUF(7, "EPRT %s:%u detected\n",
514 			      IP_VS_DBG_ADDR(cp->af, &to), ntohs(port));
515 
516 		/* Now update or create a connection entry for it */
517 		IP_VS_DBG_BUF(7, "protocol %s %s:%u %s:%u\n",
518 			      ip_vs_proto_name(ipvsh->protocol),
519 			      IP_VS_DBG_ADDR(cp->af, &to), ntohs(port),
520 			      IP_VS_DBG_ADDR(cp->af, &cp->vaddr),
521 			      ntohs(cp->vport)-1);
522 	} else {
523 		return 1;
524 	}
525 
526 	/* Passive mode off */
527 	cp->app_data = (void *) IP_VS_FTP_ACTIVE;
528 
529 	{
530 		struct ip_vs_conn_param p;
531 		ip_vs_conn_fill_param(cp->ipvs, cp->af,
532 				      ipvsh->protocol, &to, port, &cp->vaddr,
533 				      htons(ntohs(cp->vport)-1), &p);
534 		n_cp = ip_vs_conn_in_get(&p);
535 		if (!n_cp) {
536 			n_cp = ip_vs_conn_new(&p, cp->af, &cp->daddr,
537 					      htons(ntohs(cp->dport)-1),
538 					      IP_VS_CONN_F_NFCT, cp->dest,
539 					      skb->mark);
540 			if (!n_cp)
541 				return 0;
542 
543 			/* add its controller */
544 			ip_vs_control_add(n_cp, cp);
545 		}
546 	}
547 
548 	/*
549 	 *	Move tunnel to listen state
550 	 */
551 	ip_vs_tcp_conn_listen(n_cp);
552 	ip_vs_conn_put(n_cp);
553 
554 	return 1;
555 }
556 
557 
558 static struct ip_vs_app ip_vs_ftp = {
559 	.name =		"ftp",
560 	.type =		IP_VS_APP_TYPE_FTP,
561 	.protocol =	IPPROTO_TCP,
562 	.module =	THIS_MODULE,
563 	.incs_list =	LIST_HEAD_INIT(ip_vs_ftp.incs_list),
564 	.init_conn =	ip_vs_ftp_init_conn,
565 	.done_conn =	ip_vs_ftp_done_conn,
566 	.bind_conn =	NULL,
567 	.unbind_conn =	NULL,
568 	.pkt_out =	ip_vs_ftp_out,
569 	.pkt_in =	ip_vs_ftp_in,
570 };
571 
572 /*
573  *	per netns ip_vs_ftp initialization
574  */
__ip_vs_ftp_init(struct net * net)575 static int __net_init __ip_vs_ftp_init(struct net *net)
576 {
577 	int i, ret;
578 	struct ip_vs_app *app;
579 	struct netns_ipvs *ipvs = net_ipvs(net);
580 
581 	if (!ipvs)
582 		return -ENOENT;
583 
584 	app = register_ip_vs_app(ipvs, &ip_vs_ftp);
585 	if (IS_ERR(app))
586 		return PTR_ERR(app);
587 
588 	for (i = 0; i < ports_count; i++) {
589 		if (!ports[i])
590 			continue;
591 		ret = register_ip_vs_app_inc(ipvs, app, app->protocol, ports[i]);
592 		if (ret)
593 			goto err_unreg;
594 	}
595 	return 0;
596 
597 err_unreg:
598 	unregister_ip_vs_app(ipvs, &ip_vs_ftp);
599 	return ret;
600 }
601 /*
602  *	netns exit
603  */
__ip_vs_ftp_exit(struct net * net)604 static void __ip_vs_ftp_exit(struct net *net)
605 {
606 	struct netns_ipvs *ipvs = net_ipvs(net);
607 
608 	if (!ipvs)
609 		return;
610 
611 	unregister_ip_vs_app(ipvs, &ip_vs_ftp);
612 }
613 
614 static struct pernet_operations ip_vs_ftp_ops = {
615 	.init = __ip_vs_ftp_init,
616 	.exit = __ip_vs_ftp_exit,
617 };
618 
ip_vs_ftp_init(void)619 static int __init ip_vs_ftp_init(void)
620 {
621 	/* rcu_barrier() is called by netns on error */
622 	return register_pernet_subsys(&ip_vs_ftp_ops);
623 }
624 
625 /*
626  *	ip_vs_ftp finish.
627  */
ip_vs_ftp_exit(void)628 static void __exit ip_vs_ftp_exit(void)
629 {
630 	unregister_pernet_subsys(&ip_vs_ftp_ops);
631 	/* rcu_barrier() is called by netns */
632 }
633 
634 
635 module_init(ip_vs_ftp_init);
636 module_exit(ip_vs_ftp_exit);
637 MODULE_LICENSE("GPL");
638