[net-next-2.6.git] / net / netfilter / ipvs / ip_vs_ftp.c

/*
 * ip_vs_ftp.c: IPVS ftp application module
 *
 * Authors:	Wensong Zhang <wensong@linuxvirtualserver.org>
 *
 * Changes:
 *
 *
 *	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.
 *
 * Most code here is taken from ip_masq_ftp.c in kernel 2.2. The difference
 * is that ip_vs_ftp module handles the reverse direction to ip_masq_ftp.
 *
 *		IP_MASQ_FTP ftp masquerading module
 *
 * Version:	@(#)ip_masq_ftp.c 0.04   02/05/96
 *
 * Author:	Wouter Gadeyne
 *
 */

#define KMSG_COMPONENT "IPVS"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/netfilter.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_helper.h>
#include <linux/gfp.h>
#include <net/protocol.h>
#include <net/tcp.h>
#include <asm/unaligned.h>

#include <net/ip_vs.h>


#define SERVER_STRING "227 Entering Passive Mode ("
#define CLIENT_STRING "PORT "


/*
 * List of ports (up to IP_VS_APP_MAX_PORTS) to be handled by helper
 * First port is set to the default port.
 */
static unsigned short ports[IP_VS_APP_MAX_PORTS] = {21, 0};
module_param_array(ports, ushort, NULL, 0);
MODULE_PARM_DESC(ports, "Ports to monitor for FTP control commands");


/*	Dummy variable */
static int ip_vs_ftp_pasv;


static int
ip_vs_ftp_init_conn(struct ip_vs_app *app, struct ip_vs_conn *cp)
{
	/* We use connection tracking for the command connection */
	cp->flags |= IP_VS_CONN_F_NFCT;
	return 0;
}


static int
ip_vs_ftp_done_conn(struct ip_vs_app *app, struct ip_vs_conn *cp)
{
	return 0;
}


/*
 * Get <addr,port> from the string "xxx.xxx.xxx.xxx,ppp,ppp", started
 * with the "pattern" and terminated with the "term" character.
 * <addr,port> is in network order.
 */
static int ip_vs_ftp_get_addrport(char *data, char *data_limit,
				  const char *pattern, size_t plen, char term,
				  __be32 *addr, __be16 *port,
				  char **start, char **end)
{
	unsigned char p[6];
	int i = 0;

	if (data_limit - data < plen) {
		/* check if there is partial match */
		if (strnicmp(data, pattern, data_limit - data) == 0)
			return -1;
		else
			return 0;
	}

	if (strnicmp(data, pattern, plen) != 0) {
		return 0;
	}
	*start = data + plen;

	for (data = *start; *data != term; data++) {
		if (data == data_limit)
			return -1;
	}
	*end = data;

	memset(p, 0, sizeof(p));
	for (data = *start; data != *end; data++) {
		if (*data >= '0' && *data <= '9') {
			p[i] = p[i]*10 + *data - '0';
		} else if (*data == ',' && i < 5) {
			i++;
		} else {
			/* unexpected character */
			return -1;
		}
	}

	if (i != 5)
		return -1;

	*addr = get_unaligned((__be32 *)p);
	*port = get_unaligned((__be16 *)(p + 4));
	return 1;
}

/*
 * Look at outgoing ftp packets to catch the response to a PASV command
 * from the server (inside-to-outside).
 * When we see one, we build a connection entry with the client address,
 * client port 0 (unknown at the moment), the server address and the
 * server port.  Mark the current connection entry as a control channel
 * of the new entry. All this work is just to make the data connection
 * can be scheduled to the right server later.
 *
 * The outgoing packet should be something like
 *   "227 Entering Passive Mode (xxx,xxx,xxx,xxx,ppp,ppp)".
 * xxx,xxx,xxx,xxx is the server address, ppp,ppp is the server port number.
 */
static int ip_vs_ftp_out(struct ip_vs_app *app, struct ip_vs_conn *cp,
			 struct sk_buff *skb, int *diff)
{
	struct iphdr *iph;
	struct tcphdr *th;
	char *data, *data_limit;
	char *start, *end;
	union nf_inet_addr from;
	__be16 port;
	struct ip_vs_conn *n_cp;
	char buf[24];		/* xxx.xxx.xxx.xxx,ppp,ppp\000 */
	unsigned buf_len;
	int ret = 0;
	enum ip_conntrack_info ctinfo;
	struct nf_conn *ct;

#ifdef CONFIG_IP_VS_IPV6
	/* This application helper doesn't work with IPv6 yet,
	 * so turn this into a no-op for IPv6 packets
	 */
	if (cp->af == AF_INET6)
		return 1;
#endif

	*diff = 0;

	/* Only useful for established sessions */
	if (cp->state != IP_VS_TCP_S_ESTABLISHED)
		return 1;

	/* Linear packets are much easier to deal with. */
	if (!skb_make_writable(skb, skb->len))
		return 0;

	if (cp->app_data == &ip_vs_ftp_pasv) {
		iph = ip_hdr(skb);
		th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
		data = (char *)th + (th->doff << 2);
		data_limit = skb_tail_pointer(skb);

		if (ip_vs_ftp_get_addrport(data, data_limit,
					   SERVER_STRING,
					   sizeof(SERVER_STRING)-1, ')',
					   &from.ip, &port,
					   &start, &end) != 1)
			return 1;

		IP_VS_DBG(7, "PASV response (%pI4:%d) -> %pI4:%d detected\n",
			  &from.ip, ntohs(port), &cp->caddr.ip, 0);

		/*
		 * Now update or create an connection entry for it
		 */
		{
			struct ip_vs_conn_param p;
			ip_vs_conn_fill_param(AF_INET, iph->protocol,
					      &from, port, &cp->caddr, 0, &p);
			n_cp = ip_vs_conn_out_get(&p);
		}
		if (!n_cp) {
			struct ip_vs_conn_param p;
			ip_vs_conn_fill_param(AF_INET, IPPROTO_TCP, &cp->caddr,
					      0, &cp->vaddr, port, &p);
			n_cp = ip_vs_conn_new(&p, &from, port,
					      IP_VS_CONN_F_NO_CPORT |
					      IP_VS_CONN_F_NFCT,
					      cp->dest);
			if (!n_cp)
				return 0;

			/* add its controller */
			ip_vs_control_add(n_cp, cp);
		}

		/*
		 * Replace the old passive address with the new one
		 */
		from.ip = n_cp->vaddr.ip;
		port = n_cp->vport;
		snprintf(buf, sizeof(buf), "%u,%u,%u,%u,%u,%u",
			 ((unsigned char *)&from.ip)[0],
			 ((unsigned char *)&from.ip)[1],
			 ((unsigned char *)&from.ip)[2],
			 ((unsigned char *)&from.ip)[3],
			 ntohs(port) >> 8,
			 ntohs(port) & 0xFF);

		buf_len = strlen(buf);

		ct = nf_ct_get(skb, &ctinfo);
		if (ct && !nf_ct_is_untracked(ct) && nfct_nat(ct)) {
			/* If mangling fails this function will return 0
			 * which will cause the packet to be dropped.
			 * Mangling can only fail under memory pressure,
			 * hopefully it will succeed on the retransmitted
			 * packet.
			 */
			ret = nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
						       start-data, end-start,
						       buf, buf_len);
			if (ret) {
				ip_vs_nfct_expect_related(skb, ct, n_cp,
							  IPPROTO_TCP, 0, 0);
				if (skb->ip_summed == CHECKSUM_COMPLETE)
					skb->ip_summed = CHECKSUM_UNNECESSARY;
				/* csum is updated */
				ret = 1;
			}
		}

		/*
		 * Not setting 'diff' is intentional, otherwise the sequence
		 * would be adjusted twice.
		 */

		cp->app_data = NULL;
		ip_vs_tcp_conn_listen(n_cp);
		ip_vs_conn_put(n_cp);
		return ret;
	}
	return 1;
}


/*
 * Look at incoming ftp packets to catch the PASV/PORT command
 * (outside-to-inside).
 *
 * The incoming packet having the PORT command should be something like
 *      "PORT xxx,xxx,xxx,xxx,ppp,ppp\n".
 * xxx,xxx,xxx,xxx is the client address, ppp,ppp is the client port number.
 * In this case, we create a connection entry using the client address and
 * port, so that the active ftp data connection from the server can reach
 * the client.
 */
static int ip_vs_ftp_in(struct ip_vs_app *app, struct ip_vs_conn *cp,
			struct sk_buff *skb, int *diff)
{
	struct iphdr *iph;
	struct tcphdr *th;
	char *data, *data_start, *data_limit;
	char *start, *end;
	union nf_inet_addr to;
	__be16 port;
	struct ip_vs_conn *n_cp;

#ifdef CONFIG_IP_VS_IPV6
	/* This application helper doesn't work with IPv6 yet,
	 * so turn this into a no-op for IPv6 packets
	 */
	if (cp->af == AF_INET6)
		return 1;
#endif

	/* no diff required for incoming packets */
	*diff = 0;

	/* Only useful for established sessions */
	if (cp->state != IP_VS_TCP_S_ESTABLISHED)
		return 1;

	/* Linear packets are much easier to deal with. */
	if (!skb_make_writable(skb, skb->len))
		return 0;

	/*
	 * Detecting whether it is passive
	 */
	iph = ip_hdr(skb);
	th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);

	/* Since there may be OPTIONS in the TCP packet and the HLEN is
	   the length of the header in 32-bit multiples, it is accurate
	   to calculate data address by th+HLEN*4 */
	data = data_start = (char *)th + (th->doff << 2);
	data_limit = skb_tail_pointer(skb);

	while (data <= data_limit - 6) {
		if (strnicmp(data, "PASV\r\n", 6) == 0) {
			/* Passive mode on */
			IP_VS_DBG(7, "got PASV at %td of %td\n",
				  data - data_start,
				  data_limit - data_start);
			cp->app_data = &ip_vs_ftp_pasv;
			return 1;
		}
		data++;
	}

	/*
	 * To support virtual FTP server, the scenerio is as follows:
	 *       FTP client ----> Load Balancer ----> FTP server
	 * First detect the port number in the application data,
	 * then create a new connection entry for the coming data
	 * connection.
	 */
	if (ip_vs_ftp_get_addrport(data_start, data_limit,
				   CLIENT_STRING, sizeof(CLIENT_STRING)-1,
				   '\r', &to.ip, &port,
				   &start, &end) != 1)
		return 1;

	IP_VS_DBG(7, "PORT %pI4:%d detected\n", &to.ip, ntohs(port));

	/* Passive mode off */
	cp->app_data = NULL;

	/*
	 * Now update or create a connection entry for it
	 */
	IP_VS_DBG(7, "protocol %s %pI4:%d %pI4:%d\n",
		  ip_vs_proto_name(iph->protocol),
		  &to.ip, ntohs(port), &cp->vaddr.ip, 0);

	{
		struct ip_vs_conn_param p;
		ip_vs_conn_fill_param(AF_INET, iph->protocol, &to, port,
				      &cp->vaddr, htons(ntohs(cp->vport)-1),
				      &p);
		n_cp = ip_vs_conn_in_get(&p);
		if (!n_cp) {
			n_cp = ip_vs_conn_new(&p, &cp->daddr,
					      htons(ntohs(cp->dport)-1),
					      IP_VS_CONN_F_NFCT, cp->dest);
			if (!n_cp)
				return 0;

			/* add its controller */
			ip_vs_control_add(n_cp, cp);
		}
	}

	/*
	 *	Move tunnel to listen state
	 */
	ip_vs_tcp_conn_listen(n_cp);
	ip_vs_conn_put(n_cp);

	return 1;
}


static struct ip_vs_app ip_vs_ftp = {
	.name =		"ftp",
	.type =		IP_VS_APP_TYPE_FTP,
	.protocol =	IPPROTO_TCP,
	.module =	THIS_MODULE,
	.incs_list =	LIST_HEAD_INIT(ip_vs_ftp.incs_list),
	.init_conn =	ip_vs_ftp_init_conn,
	.done_conn =	ip_vs_ftp_done_conn,
	.bind_conn =	NULL,
	.unbind_conn =	NULL,
	.pkt_out =	ip_vs_ftp_out,
	.pkt_in =	ip_vs_ftp_in,
};


/*
 *	ip_vs_ftp initialization
 */
static int __init ip_vs_ftp_init(void)
{
	int i, ret;
	struct ip_vs_app *app = &ip_vs_ftp;

	ret = register_ip_vs_app(app);
	if (ret)
		return ret;

	for (i=0; i<IP_VS_APP_MAX_PORTS; i++) {
		if (!ports[i])
			continue;
		ret = register_ip_vs_app_inc(app, app->protocol, ports[i]);
		if (ret)
			break;
		pr_info("%s: loaded support on port[%d] = %d\n",
			app->name, i, ports[i]);
	}

	if (ret)
		unregister_ip_vs_app(app);

	return ret;
}


/*
 *	ip_vs_ftp finish.
 */
static void __exit ip_vs_ftp_exit(void)
{
	unregister_ip_vs_app(&ip_vs_ftp);
}


module_init(ip_vs_ftp_init);
module_exit(ip_vs_ftp_exit);
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* ip_vs_ftp.c: IPVS ftp application module
	3	*
1da177e4 LT	4	* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
	5	*
	6	* Changes:
	7	*
	8	*
	9	* This program is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU General Public License
	11	* as published by the Free Software Foundation; either version
	12	* 2 of the License, or (at your option) any later version.
	13	*
	14	* Most code here is taken from ip_masq_ftp.c in kernel 2.2. The difference
	15	* is that ip_vs_ftp module handles the reverse direction to ip_masq_ftp.
	16	*
	17	* IP_MASQ_FTP ftp masquerading module
	18	*
	19	* Version: @(#)ip_masq_ftp.c 0.04 02/05/96
	20	*
	21	* Author: Wouter Gadeyne
	22	*
	23	*/
	24
9aada7ac HE	25	#define KMSG_COMPONENT "IPVS"
	26	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
	27
1da177e4 LT	28	#include <linux/module.h>
	29	#include <linux/moduleparam.h>
	30	#include <linux/kernel.h>
	31	#include <linux/skbuff.h>
	32	#include <linux/in.h>
	33	#include <linux/ip.h>
af1e1cf0	34	#include <linux/netfilter.h>
7f1c4075 HE	35	#include <net/netfilter/nf_conntrack.h>
7f1c4075 HE	36	#include <net/netfilter/nf_conntrack_expect.h>
7bcbf81a	37	#include <net/netfilter/nf_nat.h>
7f1c4075	38	#include <net/netfilter/nf_nat_helper.h>
5a0e3ad6	39	#include <linux/gfp.h>
1da177e4 LT	40	#include <net/protocol.h>
1da177e4 LT	41	#include <net/tcp.h>
96d2ca4e	42	#include <asm/unaligned.h>
1da177e4 LT	43
	44	#include <net/ip_vs.h>
	45
	46
	47	#define SERVER_STRING "227 Entering Passive Mode ("
	48	#define CLIENT_STRING "PORT "
	49
	50
	51	/*
	52	* List of ports (up to IP_VS_APP_MAX_PORTS) to be handled by helper
	53	* First port is set to the default port.
	54	*/
28b06c38 SH	55	static unsigned short ports[IP_VS_APP_MAX_PORTS] = {21, 0};
28b06c38 SH	56	module_param_array(ports, ushort, NULL, 0);
70e76b76	57	MODULE_PARM_DESC(ports, "Ports to monitor for FTP control commands");
1da177e4	58
1da177e4 LT	59
	60	/* Dummy variable */
	61	static int ip_vs_ftp_pasv;
	62
	63
	64	static int
	65	ip_vs_ftp_init_conn(struct ip_vs_app app, struct ip_vs_conn cp)
	66	{
f4bc17cd JA	67	/* We use connection tracking for the command connection */
f4bc17cd JA	68	cp->flags \|= IP_VS_CONN_F_NFCT;
1da177e4 LT	69	return 0;
	70	}
	71
	72
	73	static int
	74	ip_vs_ftp_done_conn(struct ip_vs_app app, struct ip_vs_conn cp)
	75	{
	76	return 0;
	77	}
	78
	79
	80	/*
	81	* Get <addr,port> from the string "xxx.xxx.xxx.xxx,ppp,ppp", started
	82	* with the "pattern" and terminated with the "term" character.
	83	* <addr,port> is in network order.
	84	*/
	85	static int ip_vs_ftp_get_addrport(char data, char data_limit,
	86	const char *pattern, size_t plen, char term,
014d730d	87	__be32 addr, __be16 port,
1da177e4 LT	88	char start, char end)
	89	{
	90	unsigned char p[6];
	91	int i = 0;
	92
	93	if (data_limit - data < plen) {
	94	/* check if there is partial match */
	95	if (strnicmp(data, pattern, data_limit - data) == 0)
	96	return -1;
	97	else
	98	return 0;
	99	}
	100
	101	if (strnicmp(data, pattern, plen) != 0) {
	102	return 0;
	103	}
	104	*start = data + plen;
	105
	106	for (data = start; data != term; data++) {
	107	if (data == data_limit)
	108	return -1;
	109	}
	110	*end = data;
	111
	112	memset(p, 0, sizeof(p));
	113	for (data = start; data != end; data++) {
	114	if (data >= '0' && data <= '9') {
	115	p[i] = p[i]10 + data - '0';
	116	} else if (*data == ',' && i < 5) {
	117	i++;
	118	} else {
	119	/* unexpected character */
	120	return -1;
	121	}
	122	}
	123
	124	if (i != 5)
	125	return -1;
	126
96d2ca4e AV	127	addr = get_unaligned((__be32 )p);
96d2ca4e AV	128	port = get_unaligned((__be16 )(p + 4));
1da177e4 LT	129	return 1;
	130	}
	131
1da177e4 LT	132	/*
	133	* Look at outgoing ftp packets to catch the response to a PASV command
	134	* from the server (inside-to-outside).
	135	* When we see one, we build a connection entry with the client address,
	136	* client port 0 (unknown at the moment), the server address and the
	137	* server port. Mark the current connection entry as a control channel
	138	* of the new entry. All this work is just to make the data connection
	139	* can be scheduled to the right server later.
	140	*
	141	* The outgoing packet should be something like
	142	* "227 Entering Passive Mode (xxx,xxx,xxx,xxx,ppp,ppp)".
	143	* xxx,xxx,xxx,xxx is the server address, ppp,ppp is the server port number.
	144	*/
	145	static int ip_vs_ftp_out(struct ip_vs_app app, struct ip_vs_conn cp,
3db05fea	146	struct sk_buff skb, int diff)
1da177e4 LT	147	{
	148	struct iphdr *iph;
	149	struct tcphdr *th;
	150	char data, data_limit;
	151	char start, end;
28364a59	152	union nf_inet_addr from;
014d730d	153	__be16 port;
1da177e4 LT	154	struct ip_vs_conn *n_cp;
	155	char buf[24]; /* xxx.xxx.xxx.xxx,ppp,ppp\000 */
	156	unsigned buf_len;
7f1c4075 HE	157	int ret = 0;
	158	enum ip_conntrack_info ctinfo;
	159	struct nf_conn *ct;
1da177e4	160
a0eb662f JV	161	#ifdef CONFIG_IP_VS_IPV6
	162	/* This application helper doesn't work with IPv6 yet,
	163	* so turn this into a no-op for IPv6 packets
	164	*/
	165	if (cp->af == AF_INET6)
	166	return 1;
	167	#endif
	168
1da177e4 LT	169	*diff = 0;
	170
	171	/* Only useful for established sessions */
	172	if (cp->state != IP_VS_TCP_S_ESTABLISHED)
	173	return 1;
	174
	175	/* Linear packets are much easier to deal with. */
3db05fea	176	if (!skb_make_writable(skb, skb->len))
1da177e4 LT	177	return 0;
	178
	179	if (cp->app_data == &ip_vs_ftp_pasv) {
3db05fea	180	iph = ip_hdr(skb);
1da177e4 LT	181	th = (struct tcphdr )&(((char )iph)[iph->ihl*4]);
1da177e4 LT	182	data = (char *)th + (th->doff << 2);
3db05fea	183	data_limit = skb_tail_pointer(skb);
1da177e4 LT	184
	185	if (ip_vs_ftp_get_addrport(data, data_limit,
	186	SERVER_STRING,
	187	sizeof(SERVER_STRING)-1, ')',
28364a59	188	&from.ip, &port,
1da177e4 LT	189	&start, &end) != 1)
	190	return 1;
	191
14d5e834 HH	192	IP_VS_DBG(7, "PASV response (%pI4:%d) -> %pI4:%d detected\n",
14d5e834 HH	193	&from.ip, ntohs(port), &cp->caddr.ip, 0);
1da177e4 LT	194
	195	/*
	196	* Now update or create an connection entry for it
	197	*/
f11017ec SH	198	{
	199	struct ip_vs_conn_param p;
	200	ip_vs_conn_fill_param(AF_INET, iph->protocol,
	201	&from, port, &cp->caddr, 0, &p);
	202	n_cp = ip_vs_conn_out_get(&p);
	203	}
1da177e4	204	if (!n_cp) {
f11017ec SH	205	struct ip_vs_conn_param p;
	206	ip_vs_conn_fill_param(AF_INET, IPPROTO_TCP, &cp->caddr,
	207	0, &cp->vaddr, port, &p);
	208	n_cp = ip_vs_conn_new(&p, &from, port,
f4bc17cd JA	209	IP_VS_CONN_F_NO_CPORT \|
f4bc17cd JA	210	IP_VS_CONN_F_NFCT,
1da177e4 LT	211	cp->dest);
	212	if (!n_cp)
	213	return 0;
	214
	215	/* add its controller */
	216	ip_vs_control_add(n_cp, cp);
	217	}
	218
	219	/*
	220	* Replace the old passive address with the new one
	221	*/
28364a59	222	from.ip = n_cp->vaddr.ip;
1da177e4	223	port = n_cp->vport;
1da05f50 JP	224	snprintf(buf, sizeof(buf), "%u,%u,%u,%u,%u,%u",
	225	((unsigned char *)&from.ip)[0],
	226	((unsigned char *)&from.ip)[1],
	227	((unsigned char *)&from.ip)[2],
	228	((unsigned char *)&from.ip)[3],
	229	ntohs(port) >> 8,
	230	ntohs(port) & 0xFF);
	231
1da177e4 LT	232	buf_len = strlen(buf);
1da177e4 LT	233
7f1c4075	234	ct = nf_ct_get(skb, &ctinfo);
7bcbf81a	235	if (ct && !nf_ct_is_untracked(ct) && nfct_nat(ct)) {
7f1c4075 HE	236	/* If mangling fails this function will return 0
	237	* which will cause the packet to be dropped.
	238	* Mangling can only fail under memory pressure,
	239	* hopefully it will succeed on the retransmitted
	240	* packet.
	241	*/
	242	ret = nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
	243	start-data, end-start,
	244	buf, buf_len);
8b27b10f	245	if (ret) {
f4bc17cd JA	246	ip_vs_nfct_expect_related(skb, ct, n_cp,
f4bc17cd JA	247	IPPROTO_TCP, 0, 0);
8b27b10f JA	248	if (skb->ip_summed == CHECKSUM_COMPLETE)
	249	skb->ip_summed = CHECKSUM_UNNECESSARY;
	250	/* csum is updated */
	251	ret = 1;
	252	}
7f1c4075 HE	253	}
7f1c4075 HE	254
1da177e4	255	/*
7f1c4075 HE	256	* Not setting 'diff' is intentional, otherwise the sequence
7f1c4075 HE	257	* would be adjusted twice.
1da177e4	258	*/
1da177e4 LT	259
	260	cp->app_data = NULL;
	261	ip_vs_tcp_conn_listen(n_cp);
	262	ip_vs_conn_put(n_cp);
	263	return ret;
	264	}
	265	return 1;
	266	}
	267
	268
	269	/*
	270	* Look at incoming ftp packets to catch the PASV/PORT command
	271	* (outside-to-inside).
	272	*
	273	* The incoming packet having the PORT command should be something like
	274	* "PORT xxx,xxx,xxx,xxx,ppp,ppp\n".
	275	* xxx,xxx,xxx,xxx is the client address, ppp,ppp is the client port number.
	276	* In this case, we create a connection entry using the client address and
	277	* port, so that the active ftp data connection from the server can reach
	278	* the client.
	279	*/
	280	static int ip_vs_ftp_in(struct ip_vs_app app, struct ip_vs_conn cp,
3db05fea	281	struct sk_buff skb, int diff)
1da177e4 LT	282	{
	283	struct iphdr *iph;
	284	struct tcphdr *th;
	285	char data, data_start, *data_limit;
	286	char start, end;
28364a59	287	union nf_inet_addr to;
014d730d	288	__be16 port;
1da177e4 LT	289	struct ip_vs_conn *n_cp;
1da177e4 LT	290
a0eb662f JV	291	#ifdef CONFIG_IP_VS_IPV6
	292	/* This application helper doesn't work with IPv6 yet,
	293	* so turn this into a no-op for IPv6 packets
	294	*/
	295	if (cp->af == AF_INET6)
	296	return 1;
	297	#endif
	298
1da177e4 LT	299	/* no diff required for incoming packets */
	300	*diff = 0;
	301
	302	/* Only useful for established sessions */
	303	if (cp->state != IP_VS_TCP_S_ESTABLISHED)
	304	return 1;
	305
	306	/* Linear packets are much easier to deal with. */
3db05fea	307	if (!skb_make_writable(skb, skb->len))
1da177e4 LT	308	return 0;
	309
	310	/*
	311	* Detecting whether it is passive
	312	*/
3db05fea	313	iph = ip_hdr(skb);
1da177e4 LT	314	th = (struct tcphdr )&(((char )iph)[iph->ihl*4]);
	315
	316	/* Since there may be OPTIONS in the TCP packet and the HLEN is
	317	the length of the header in 32-bit multiples, it is accurate
	318	to calculate data address by th+HLEN4 /
	319	data = data_start = (char *)th + (th->doff << 2);
3db05fea	320	data_limit = skb_tail_pointer(skb);
1da177e4 LT	321
	322	while (data <= data_limit - 6) {
	323	if (strnicmp(data, "PASV\r\n", 6) == 0) {
	324	/* Passive mode on */
5e7ddac7	325	IP_VS_DBG(7, "got PASV at %td of %td\n",
1da177e4 LT	326	data - data_start,
	327	data_limit - data_start);
	328	cp->app_data = &ip_vs_ftp_pasv;
	329	return 1;
	330	}
	331	data++;
	332	}
	333
	334	/*
	335	* To support virtual FTP server, the scenerio is as follows:
	336	* FTP client ----> Load Balancer ----> FTP server
	337	* First detect the port number in the application data,
	338	* then create a new connection entry for the coming data
	339	* connection.
	340	*/
	341	if (ip_vs_ftp_get_addrport(data_start, data_limit,
	342	CLIENT_STRING, sizeof(CLIENT_STRING)-1,
28364a59	343	'\r', &to.ip, &port,
1da177e4 LT	344	&start, &end) != 1)
	345	return 1;
	346
14d5e834	347	IP_VS_DBG(7, "PORT %pI4:%d detected\n", &to.ip, ntohs(port));
1da177e4 LT	348
	349	/* Passive mode off */
	350	cp->app_data = NULL;
	351
	352	/*
	353	* Now update or create a connection entry for it
	354	*/
14d5e834	355	IP_VS_DBG(7, "protocol %s %pI4:%d %pI4:%d\n",
1da177e4	356	ip_vs_proto_name(iph->protocol),
14d5e834	357	&to.ip, ntohs(port), &cp->vaddr.ip, 0);
1da177e4	358
f11017ec SH	359	{
	360	struct ip_vs_conn_param p;
	361	ip_vs_conn_fill_param(AF_INET, iph->protocol, &to, port,
28364a59	362	&cp->vaddr, htons(ntohs(cp->vport)-1),
f11017ec SH	363	&p);
	364	n_cp = ip_vs_conn_in_get(&p);
	365	if (!n_cp) {
	366	n_cp = ip_vs_conn_new(&p, &cp->daddr,
	367	htons(ntohs(cp->dport)-1),
	368	IP_VS_CONN_F_NFCT, cp->dest);
	369	if (!n_cp)
	370	return 0;
1da177e4	371
f11017ec SH	372	/* add its controller */
	373	ip_vs_control_add(n_cp, cp);
	374	}
1da177e4 LT	375	}
	376
	377	/*
	378	* Move tunnel to listen state
	379	*/
	380	ip_vs_tcp_conn_listen(n_cp);
	381	ip_vs_conn_put(n_cp);
	382
	383	return 1;
	384	}
	385
	386
	387	static struct ip_vs_app ip_vs_ftp = {
	388	.name = "ftp",
	389	.type = IP_VS_APP_TYPE_FTP,
	390	.protocol = IPPROTO_TCP,
	391	.module = THIS_MODULE,
	392	.incs_list = LIST_HEAD_INIT(ip_vs_ftp.incs_list),
	393	.init_conn = ip_vs_ftp_init_conn,
	394	.done_conn = ip_vs_ftp_done_conn,
	395	.bind_conn = NULL,
	396	.unbind_conn = NULL,
	397	.pkt_out = ip_vs_ftp_out,
	398	.pkt_in = ip_vs_ftp_in,
	399	};
	400
	401
	402	/*
	403	* ip_vs_ftp initialization
	404	*/
	405	static int __init ip_vs_ftp_init(void)
	406	{
	407	int i, ret;
	408	struct ip_vs_app *app = &ip_vs_ftp;
	409
	410	ret = register_ip_vs_app(app);
	411	if (ret)
	412	return ret;
	413
	414	for (i=0; i<IP_VS_APP_MAX_PORTS; i++) {
	415	if (!ports[i])
	416	continue;
	417	ret = register_ip_vs_app_inc(app, app->protocol, ports[i]);
	418	if (ret)
	419	break;
1e3e238e HE	420	pr_info("%s: loaded support on port[%d] = %d\n",
1e3e238e HE	421	app->name, i, ports[i]);
1da177e4 LT	422	}
	423
	424	if (ret)
	425	unregister_ip_vs_app(app);
	426
	427	return ret;
	428	}
	429
	430
	431	/*
	432	* ip_vs_ftp finish.
	433	*/
	434	static void __exit ip_vs_ftp_exit(void)
	435	{
	436	unregister_ip_vs_app(&ip_vs_ftp);
	437	}
	438
	439
	440	module_init(ip_vs_ftp_init);
	441	module_exit(ip_vs_ftp_exit);
	442	MODULE_LICENSE("GPL");