[deliverable/linux.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 "
#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 int ports_count = 1;
static unsigned short ports[IP_VS_APP_MAX_PORTS] = {21, 0};
module_param_array(ports, ushort, &ports_count, 0444);
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", ignoring before "skip" 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 skip, char term,
				  __be32 *addr, __be16 *port,
				  char **start, char **end)
{
	char *s, c;
	unsigned char p[6];
	int i = 0;

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

	if (strncasecmp(data, pattern, plen) != 0) {
		return 0;
	}
	s = data + plen;
	if (skip) {
		int found = 0;

		for (;; s++) {
			if (s == data_limit)
				return -1;
			if (!found) {
				if (*s == skip)
					found = 1;
			} else if (*s != skip) {
				break;
			}
		}
	}

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

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

	if (i != 5)
		return -1;

	*start = s;
	*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 int buf_len;
	int ret = 0;
	enum ip_conntrack_info ctinfo;
	struct nf_conn *ct;
	struct net *net;

	*diff = 0;

#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

	/* 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(ip_vs_conn_net(cp), 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(ip_vs_conn_net(cp),
					      AF_INET, IPPROTO_TCP, &cp->caddr,
					      0, &cp->vaddr, port, &p);
			/* As above, this is ipv4 only */
			n_cp = ip_vs_conn_new(&p, AF_INET, &from, port,
					      IP_VS_CONN_F_NO_CPORT |
					      IP_VS_CONN_F_NFCT,
					      cp->dest, skb->mark);
			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.
			 */
			rcu_read_lock();
			ret = nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
						       iph->ihl * 4,
						       start-data, end-start,
						       buf, buf_len);
			rcu_read_unlock();
			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.
		 */

		net = skb_net(skb);
		cp->app_data = NULL;
		ip_vs_tcp_conn_listen(net, 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;
	struct net *net;

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

#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

	/* 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 (strncasecmp(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(ip_vs_conn_net(cp), 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) {
			/* This is ipv4 only */
			n_cp = ip_vs_conn_new(&p, AF_INET, &cp->daddr,
					      htons(ntohs(cp->dport)-1),
					      IP_VS_CONN_F_NFCT, cp->dest,
					      skb->mark);
			if (!n_cp)
				return 0;

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

	/*
	 *	Move tunnel to listen state
	 */
	net = skb_net(skb);
	ip_vs_tcp_conn_listen(net, 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,
};

/*
 *	per netns ip_vs_ftp initialization
 */
static int __net_init __ip_vs_ftp_init(struct net *net)
{
	int i, ret;
	struct ip_vs_app *app;
	struct netns_ipvs *ipvs = net_ipvs(net);

	if (!ipvs)
		return -ENOENT;

	app = register_ip_vs_app(net, &ip_vs_ftp);
	if (IS_ERR(app))
		return PTR_ERR(app);

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

err_unreg:
	unregister_ip_vs_app(net, &ip_vs_ftp);
	return ret;
}
/*
 *	netns exit
 */
static void __ip_vs_ftp_exit(struct net *net)
{
	unregister_ip_vs_app(net, &ip_vs_ftp);
}

static struct pernet_operations ip_vs_ftp_ops = {
	.init = __ip_vs_ftp_init,
	.exit = __ip_vs_ftp_exit,
};

static int __init ip_vs_ftp_init(void)
{
	int rv;

	rv = register_pernet_subsys(&ip_vs_ftp_ops);
	/* rcu_barrier() is called by netns on error */
	return rv;
}

/*
 *	ip_vs_ftp finish.
 */
static void __exit ip_vs_ftp_exit(void)
{
	unregister_pernet_subsys(&ip_vs_ftp_ops);
	/* rcu_barrier() is called by netns */
}


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
c3aa1bd3 JA	47	#define SERVER_STRING "227 "
c3aa1bd3 JA	48	#define CLIENT_STRING "PORT"
1da177e4 LT	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	*/
52669dfa	55	static unsigned int ports_count = 1;
28b06c38	56	static unsigned short ports[IP_VS_APP_MAX_PORTS] = {21, 0};
52669dfa	57	module_param_array(ports, ushort, &ports_count, 0444);
70e76b76	58	MODULE_PARM_DESC(ports, "Ports to monitor for FTP control commands");
1da177e4	59
1da177e4 LT	60
	61	/* Dummy variable */
	62	static int ip_vs_ftp_pasv;
	63
	64
	65	static int
	66	ip_vs_ftp_init_conn(struct ip_vs_app app, struct ip_vs_conn cp)
	67	{
f4bc17cd JA	68	/* We use connection tracking for the command connection */
f4bc17cd JA	69	cp->flags \|= IP_VS_CONN_F_NFCT;
1da177e4 LT	70	return 0;
	71	}
	72
	73
	74	static int
	75	ip_vs_ftp_done_conn(struct ip_vs_app app, struct ip_vs_conn cp)
	76	{
	77	return 0;
	78	}
	79
	80
	81	/*
	82	* Get <addr,port> from the string "xxx.xxx.xxx.xxx,ppp,ppp", started
c3aa1bd3 JA	83	* with the "pattern", ignoring before "skip" and terminated with
c3aa1bd3 JA	84	* the "term" character.
1da177e4 LT	85	* <addr,port> is in network order.
	86	*/
	87	static int ip_vs_ftp_get_addrport(char data, char data_limit,
c3aa1bd3 JA	88	const char *pattern, size_t plen,
c3aa1bd3 JA	89	char skip, char term,
014d730d	90	__be32 addr, __be16 port,
1da177e4 LT	91	char start, char end)
1da177e4 LT	92	{
c3aa1bd3	93	char *s, c;
1da177e4 LT	94	unsigned char p[6];
	95	int i = 0;
	96
	97	if (data_limit - data < plen) {
	98	/* check if there is partial match */
18082746	99	if (strncasecmp(data, pattern, data_limit - data) == 0)
1da177e4 LT	100	return -1;
	101	else
	102	return 0;
	103	}
	104
18082746	105	if (strncasecmp(data, pattern, plen) != 0) {
1da177e4 LT	106	return 0;
1da177e4 LT	107	}
c3aa1bd3 JA	108	s = data + plen;
	109	if (skip) {
	110	int found = 0;
	111
	112	for (;; s++) {
	113	if (s == data_limit)
	114	return -1;
	115	if (!found) {
	116	if (*s == skip)
	117	found = 1;
	118	} else if (*s != skip) {
	119	break;
	120	}
	121	}
	122	}
1da177e4	123
c3aa1bd3	124	for (data = s; ; data++) {
1da177e4 LT	125	if (data == data_limit)
1da177e4 LT	126	return -1;
c3aa1bd3 JA	127	if (*data == term)
c3aa1bd3 JA	128	break;
1da177e4 LT	129	}
	130	*end = data;
	131
	132	memset(p, 0, sizeof(p));
c3aa1bd3 JA	133	for (data = s; ; data++) {
	134	c = *data;
	135	if (c == term)
	136	break;
	137	if (c >= '0' && c <= '9') {
	138	p[i] = p[i]*10 + c - '0';
	139	} else if (c == ',' && i < 5) {
1da177e4 LT	140	i++;
	141	} else {
	142	/* unexpected character */
	143	return -1;
	144	}
	145	}
	146
	147	if (i != 5)
	148	return -1;
	149
c3aa1bd3 JA	150	*start = s;
	151	addr = get_unaligned((__be32 ) p);
	152	port = get_unaligned((__be16 ) (p + 4));
1da177e4 LT	153	return 1;
	154	}
	155
1da177e4 LT	156	/*
	157	* Look at outgoing ftp packets to catch the response to a PASV command
	158	* from the server (inside-to-outside).
	159	* When we see one, we build a connection entry with the client address,
	160	* client port 0 (unknown at the moment), the server address and the
	161	* server port. Mark the current connection entry as a control channel
	162	* of the new entry. All this work is just to make the data connection
	163	* can be scheduled to the right server later.
	164	*
	165	* The outgoing packet should be something like
	166	* "227 Entering Passive Mode (xxx,xxx,xxx,xxx,ppp,ppp)".
	167	* xxx,xxx,xxx,xxx is the server address, ppp,ppp is the server port number.
	168	*/
	169	static int ip_vs_ftp_out(struct ip_vs_app app, struct ip_vs_conn cp,
3db05fea	170	struct sk_buff skb, int diff)
1da177e4 LT	171	{
	172	struct iphdr *iph;
	173	struct tcphdr *th;
	174	char data, data_limit;
	175	char start, end;
28364a59	176	union nf_inet_addr from;
014d730d	177	__be16 port;
1da177e4 LT	178	struct ip_vs_conn *n_cp;
1da177e4 LT	179	char buf[24]; /* xxx.xxx.xxx.xxx,ppp,ppp\000 */
95c96174	180	unsigned int buf_len;
7f1c4075 HE	181	int ret = 0;
	182	enum ip_conntrack_info ctinfo;
	183	struct nf_conn *ct;
4a85b96c	184	struct net *net;
1da177e4	185
3b05ac38 DC	186	*diff = 0;
3b05ac38 DC	187
a0eb662f JV	188	#ifdef CONFIG_IP_VS_IPV6
	189	/* This application helper doesn't work with IPv6 yet,
	190	* so turn this into a no-op for IPv6 packets
	191	*/
	192	if (cp->af == AF_INET6)
	193	return 1;
	194	#endif
	195
1da177e4 LT	196	/* Only useful for established sessions */
	197	if (cp->state != IP_VS_TCP_S_ESTABLISHED)
	198	return 1;
	199
	200	/* Linear packets are much easier to deal with. */
3db05fea	201	if (!skb_make_writable(skb, skb->len))
1da177e4 LT	202	return 0;
	203
	204	if (cp->app_data == &ip_vs_ftp_pasv) {
3db05fea	205	iph = ip_hdr(skb);
1da177e4 LT	206	th = (struct tcphdr )&(((char )iph)[iph->ihl*4]);
1da177e4 LT	207	data = (char *)th + (th->doff << 2);
3db05fea	208	data_limit = skb_tail_pointer(skb);
1da177e4 LT	209
	210	if (ip_vs_ftp_get_addrport(data, data_limit,
	211	SERVER_STRING,
c3aa1bd3 JA	212	sizeof(SERVER_STRING)-1,
c3aa1bd3 JA	213	'(', ')',
28364a59	214	&from.ip, &port,
1da177e4 LT	215	&start, &end) != 1)
	216	return 1;
	217
14d5e834 HH	218	IP_VS_DBG(7, "PASV response (%pI4:%d) -> %pI4:%d detected\n",
14d5e834 HH	219	&from.ip, ntohs(port), &cp->caddr.ip, 0);
1da177e4 LT	220
	221	/*
	222	* Now update or create an connection entry for it
	223	*/
f11017ec SH	224	{
f11017ec SH	225	struct ip_vs_conn_param p;
6e67e586 HS	226	ip_vs_conn_fill_param(ip_vs_conn_net(cp), AF_INET,
	227	iph->protocol, &from, port,
	228	&cp->caddr, 0, &p);
f11017ec SH	229	n_cp = ip_vs_conn_out_get(&p);
f11017ec SH	230	}
1da177e4	231	if (!n_cp) {
f11017ec	232	struct ip_vs_conn_param p;
6e67e586 HS	233	ip_vs_conn_fill_param(ip_vs_conn_net(cp),
6e67e586 HS	234	AF_INET, IPPROTO_TCP, &cp->caddr,
f11017ec	235	0, &cp->vaddr, port, &p);
ba38528a AG	236	/* As above, this is ipv4 only */
ba38528a AG	237	n_cp = ip_vs_conn_new(&p, AF_INET, &from, port,
f4bc17cd JA	238	IP_VS_CONN_F_NO_CPORT \|
f4bc17cd JA	239	IP_VS_CONN_F_NFCT,
0e051e68	240	cp->dest, skb->mark);
1da177e4 LT	241	if (!n_cp)
	242	return 0;
	243
	244	/* add its controller */
	245	ip_vs_control_add(n_cp, cp);
	246	}
	247
	248	/*
	249	* Replace the old passive address with the new one
	250	*/
28364a59	251	from.ip = n_cp->vaddr.ip;
1da177e4	252	port = n_cp->vport;
1da05f50 JP	253	snprintf(buf, sizeof(buf), "%u,%u,%u,%u,%u,%u",
	254	((unsigned char *)&from.ip)[0],
	255	((unsigned char *)&from.ip)[1],
	256	((unsigned char *)&from.ip)[2],
	257	((unsigned char *)&from.ip)[3],
	258	ntohs(port) >> 8,
	259	ntohs(port) & 0xFF);
	260
1da177e4 LT	261	buf_len = strlen(buf);
1da177e4 LT	262
7f1c4075	263	ct = nf_ct_get(skb, &ctinfo);
7bcbf81a	264	if (ct && !nf_ct_is_untracked(ct) && nfct_nat(ct)) {
7f1c4075 HE	265	/* If mangling fails this function will return 0
	266	* which will cause the packet to be dropped.
	267	* Mangling can only fail under memory pressure,
	268	* hopefully it will succeed on the retransmitted
	269	* packet.
	270	*/
ac69269a	271	rcu_read_lock();
7f1c4075	272	ret = nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
051966c0	273	iph->ihl * 4,
7f1c4075 HE	274	start-data, end-start,
7f1c4075 HE	275	buf, buf_len);
ac69269a	276	rcu_read_unlock();
8b27b10f	277	if (ret) {
f4bc17cd JA	278	ip_vs_nfct_expect_related(skb, ct, n_cp,
f4bc17cd JA	279	IPPROTO_TCP, 0, 0);
8b27b10f JA	280	if (skb->ip_summed == CHECKSUM_COMPLETE)
	281	skb->ip_summed = CHECKSUM_UNNECESSARY;
	282	/* csum is updated */
	283	ret = 1;
	284	}
7f1c4075 HE	285	}
7f1c4075 HE	286
1da177e4	287	/*
7f1c4075 HE	288	* Not setting 'diff' is intentional, otherwise the sequence
7f1c4075 HE	289	* would be adjusted twice.
1da177e4	290	*/
1da177e4	291
4a85b96c	292	net = skb_net(skb);
1da177e4	293	cp->app_data = NULL;
4a85b96c	294	ip_vs_tcp_conn_listen(net, n_cp);
1da177e4 LT	295	ip_vs_conn_put(n_cp);
	296	return ret;
	297	}
	298	return 1;
	299	}
	300
	301
	302	/*
	303	* Look at incoming ftp packets to catch the PASV/PORT command
	304	* (outside-to-inside).
	305	*
	306	* The incoming packet having the PORT command should be something like
	307	* "PORT xxx,xxx,xxx,xxx,ppp,ppp\n".
	308	* xxx,xxx,xxx,xxx is the client address, ppp,ppp is the client port number.
	309	* In this case, we create a connection entry using the client address and
	310	* port, so that the active ftp data connection from the server can reach
	311	* the client.
	312	*/
	313	static int ip_vs_ftp_in(struct ip_vs_app app, struct ip_vs_conn cp,
3db05fea	314	struct sk_buff skb, int diff)
1da177e4 LT	315	{
	316	struct iphdr *iph;
	317	struct tcphdr *th;
	318	char data, data_start, *data_limit;
	319	char start, end;
28364a59	320	union nf_inet_addr to;
014d730d	321	__be16 port;
1da177e4	322	struct ip_vs_conn *n_cp;
4a85b96c	323	struct net *net;
1da177e4	324
3b05ac38 DC	325	/* no diff required for incoming packets */
	326	*diff = 0;
	327
a0eb662f JV	328	#ifdef CONFIG_IP_VS_IPV6
	329	/* This application helper doesn't work with IPv6 yet,
	330	* so turn this into a no-op for IPv6 packets
	331	*/
	332	if (cp->af == AF_INET6)
	333	return 1;
	334	#endif
	335
1da177e4 LT	336	/* Only useful for established sessions */
	337	if (cp->state != IP_VS_TCP_S_ESTABLISHED)
	338	return 1;
	339
	340	/* Linear packets are much easier to deal with. */
3db05fea	341	if (!skb_make_writable(skb, skb->len))
1da177e4 LT	342	return 0;
	343
	344	/*
	345	* Detecting whether it is passive
	346	*/
3db05fea	347	iph = ip_hdr(skb);
1da177e4 LT	348	th = (struct tcphdr )&(((char )iph)[iph->ihl*4]);
	349
	350	/* Since there may be OPTIONS in the TCP packet and the HLEN is
	351	the length of the header in 32-bit multiples, it is accurate
	352	to calculate data address by th+HLEN4 /
	353	data = data_start = (char *)th + (th->doff << 2);
3db05fea	354	data_limit = skb_tail_pointer(skb);
1da177e4 LT	355
1da177e4 LT	356	while (data <= data_limit - 6) {
18082746	357	if (strncasecmp(data, "PASV\r\n", 6) == 0) {
1da177e4	358	/* Passive mode on */
5e7ddac7	359	IP_VS_DBG(7, "got PASV at %td of %td\n",
1da177e4 LT	360	data - data_start,
	361	data_limit - data_start);
	362	cp->app_data = &ip_vs_ftp_pasv;
	363	return 1;
	364	}
	365	data++;
	366	}
	367
	368	/*
	369	* To support virtual FTP server, the scenerio is as follows:
	370	* FTP client ----> Load Balancer ----> FTP server
	371	* First detect the port number in the application data,
	372	* then create a new connection entry for the coming data
	373	* connection.
	374	*/
	375	if (ip_vs_ftp_get_addrport(data_start, data_limit,
	376	CLIENT_STRING, sizeof(CLIENT_STRING)-1,
c3aa1bd3	377	' ', '\r', &to.ip, &port,
1da177e4 LT	378	&start, &end) != 1)
	379	return 1;
	380
14d5e834	381	IP_VS_DBG(7, "PORT %pI4:%d detected\n", &to.ip, ntohs(port));
1da177e4 LT	382
	383	/* Passive mode off */
	384	cp->app_data = NULL;
	385
	386	/*
	387	* Now update or create a connection entry for it
	388	*/
14d5e834	389	IP_VS_DBG(7, "protocol %s %pI4:%d %pI4:%d\n",
1da177e4	390	ip_vs_proto_name(iph->protocol),
14d5e834	391	&to.ip, ntohs(port), &cp->vaddr.ip, 0);
1da177e4	392
f11017ec SH	393	{
f11017ec SH	394	struct ip_vs_conn_param p;
6e67e586 HS	395	ip_vs_conn_fill_param(ip_vs_conn_net(cp), AF_INET,
	396	iph->protocol, &to, port, &cp->vaddr,
	397	htons(ntohs(cp->vport)-1), &p);
f11017ec SH	398	n_cp = ip_vs_conn_in_get(&p);
f11017ec SH	399	if (!n_cp) {
ba38528a AG	400	/* This is ipv4 only */
ba38528a AG	401	n_cp = ip_vs_conn_new(&p, AF_INET, &cp->daddr,
f11017ec	402	htons(ntohs(cp->dport)-1),
0e051e68 HS	403	IP_VS_CONN_F_NFCT, cp->dest,
0e051e68 HS	404	skb->mark);
f11017ec SH	405	if (!n_cp)
f11017ec SH	406	return 0;
1da177e4	407
f11017ec SH	408	/* add its controller */
	409	ip_vs_control_add(n_cp, cp);
	410	}
1da177e4 LT	411	}
	412
	413	/*
	414	* Move tunnel to listen state
	415	*/
4a85b96c HS	416	net = skb_net(skb);
4a85b96c HS	417	ip_vs_tcp_conn_listen(net, n_cp);
1da177e4 LT	418	ip_vs_conn_put(n_cp);
	419
	420	return 1;
	421	}
	422
	423
	424	static struct ip_vs_app ip_vs_ftp = {
	425	.name = "ftp",
	426	.type = IP_VS_APP_TYPE_FTP,
	427	.protocol = IPPROTO_TCP,
	428	.module = THIS_MODULE,
	429	.incs_list = LIST_HEAD_INIT(ip_vs_ftp.incs_list),
	430	.init_conn = ip_vs_ftp_init_conn,
	431	.done_conn = ip_vs_ftp_done_conn,
	432	.bind_conn = NULL,
	433	.unbind_conn = NULL,
	434	.pkt_out = ip_vs_ftp_out,
	435	.pkt_in = ip_vs_ftp_in,
	436	};
	437
1da177e4	438	/*
61b1ab45	439	* per netns ip_vs_ftp initialization
1da177e4	440	*/
61b1ab45	441	static int __net_init __ip_vs_ftp_init(struct net *net)
1da177e4 LT	442	{
1da177e4 LT	443	int i, ret;
c74c0bfe HS	444	struct ip_vs_app *app;
	445	struct netns_ipvs *ipvs = net_ipvs(net);
	446
8d08d71c JA	447	if (!ipvs)
8d08d71c JA	448	return -ENOENT;
1da177e4	449
be97fdb5 JA	450	app = register_ip_vs_app(net, &ip_vs_ftp);
	451	if (IS_ERR(app))
	452	return PTR_ERR(app);
1da177e4	453
52669dfa	454	for (i = 0; i < ports_count; i++) {
1da177e4 LT	455	if (!ports[i])
1da177e4 LT	456	continue;
ab8a5e84	457	ret = register_ip_vs_app_inc(net, app, app->protocol, ports[i]);
1da177e4	458	if (ret)
c74c0bfe	459	goto err_unreg;
1e3e238e HE	460	pr_info("%s: loaded support on port[%d] = %d\n",
1e3e238e HE	461	app->name, i, ports[i]);
1da177e4	462	}
c74c0bfe	463	return 0;
1da177e4	464
c74c0bfe	465	err_unreg:
be97fdb5	466	unregister_ip_vs_app(net, &ip_vs_ftp);
1da177e4 LT	467	return ret;
1da177e4 LT	468	}
61b1ab45 HS	469	/*
	470	* netns exit
	471	*/
	472	static void __ip_vs_ftp_exit(struct net *net)
	473	{
be97fdb5	474	unregister_ip_vs_app(net, &ip_vs_ftp);
61b1ab45 HS	475	}
	476
	477	static struct pernet_operations ip_vs_ftp_ops = {
	478	.init = __ip_vs_ftp_init,
	479	.exit = __ip_vs_ftp_exit,
	480	};
1da177e4	481
d5cce208	482	static int __init ip_vs_ftp_init(void)
61b1ab45 HS	483	{
	484	int rv;
	485
	486	rv = register_pernet_subsys(&ip_vs_ftp_ops);
363c97d7	487	/* rcu_barrier() is called by netns on error */
61b1ab45 HS	488	return rv;
61b1ab45 HS	489	}
1da177e4 LT	490
	491	/*
	492	* ip_vs_ftp finish.
	493	*/
	494	static void __exit ip_vs_ftp_exit(void)
	495	{
61b1ab45	496	unregister_pernet_subsys(&ip_vs_ftp_ops);
363c97d7	497	/* rcu_barrier() is called by netns */
1da177e4 LT	498	}
	499
	500
	501	module_init(ip_vs_ftp_init);
	502	module_exit(ip_vs_ftp_exit);
	503	MODULE_LICENSE("GPL");