[net-next-2.6.git] / net / netfilter / nf_conntrack_amanda.c

/* Amanda extension for IP connection tracking
 *
 * (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca>
 * based on HW's ip_conntrack_irc.c as well as other modules
 *
 * 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.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/textsearch.h>
#include <linux/skbuff.h>
#include <linux/in.h>
#include <linux/udp.h>
#include <linux/netfilter.h>
#include <linux/gfp.h>

#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <linux/netfilter/nf_conntrack_amanda.h>

static unsigned int master_timeout __read_mostly = 300;
static char *ts_algo = "kmp";

MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");
MODULE_DESCRIPTION("Amanda connection tracking module");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ip_conntrack_amanda");
MODULE_ALIAS_NFCT_HELPER("amanda");

module_param(master_timeout, uint, 0600);
MODULE_PARM_DESC(master_timeout, "timeout for the master connection");
module_param(ts_algo, charp, 0400);
MODULE_PARM_DESC(ts_algo, "textsearch algorithm to use (default kmp)");

unsigned int (*nf_nat_amanda_hook)(struct sk_buff *skb,
				   enum ip_conntrack_info ctinfo,
				   unsigned int matchoff,
				   unsigned int matchlen,
				   struct nf_conntrack_expect *exp)
				   __read_mostly;
EXPORT_SYMBOL_GPL(nf_nat_amanda_hook);

enum amanda_strings {
	SEARCH_CONNECT,
	SEARCH_NEWLINE,
	SEARCH_DATA,
	SEARCH_MESG,
	SEARCH_INDEX,
};

static struct {
	const char		*string;
	size_t			len;
	struct ts_config	*ts;
} search[] __read_mostly = {
	[SEARCH_CONNECT] = {
		.string	= "CONNECT ",
		.len	= 8,
	},
	[SEARCH_NEWLINE] = {
		.string	= "\n",
		.len	= 1,
	},
	[SEARCH_DATA] = {
		.string	= "DATA ",
		.len	= 5,
	},
	[SEARCH_MESG] = {
		.string	= "MESG ",
		.len	= 5,
	},
	[SEARCH_INDEX] = {
		.string = "INDEX ",
		.len	= 6,
	},
};

static int amanda_help(struct sk_buff *skb,
		       unsigned int protoff,
		       struct nf_conn *ct,
		       enum ip_conntrack_info ctinfo)
{
	struct ts_state ts;
	struct nf_conntrack_expect *exp;
	struct nf_conntrack_tuple *tuple;
	unsigned int dataoff, start, stop, off, i;
	char pbuf[sizeof("65535")], *tmp;
	u_int16_t len;
	__be16 port;
	int ret = NF_ACCEPT;
	typeof(nf_nat_amanda_hook) nf_nat_amanda;

	/* Only look at packets from the Amanda server */
	if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
		return NF_ACCEPT;

	/* increase the UDP timeout of the master connection as replies from
	 * Amanda clients to the server can be quite delayed */
	nf_ct_refresh(ct, skb, master_timeout * HZ);

	/* No data? */
	dataoff = protoff + sizeof(struct udphdr);
	if (dataoff >= skb->len) {
		if (net_ratelimit())
			printk(KERN_ERR "amanda_help: skblen = %u\n", skb->len);
		return NF_ACCEPT;
	}

	memset(&ts, 0, sizeof(ts));
	start = skb_find_text(skb, dataoff, skb->len,
			      search[SEARCH_CONNECT].ts, &ts);
	if (start == UINT_MAX)
		goto out;
	start += dataoff + search[SEARCH_CONNECT].len;

	memset(&ts, 0, sizeof(ts));
	stop = skb_find_text(skb, start, skb->len,
			     search[SEARCH_NEWLINE].ts, &ts);
	if (stop == UINT_MAX)
		goto out;
	stop += start;

	for (i = SEARCH_DATA; i <= SEARCH_INDEX; i++) {
		memset(&ts, 0, sizeof(ts));
		off = skb_find_text(skb, start, stop, search[i].ts, &ts);
		if (off == UINT_MAX)
			continue;
		off += start + search[i].len;

		len = min_t(unsigned int, sizeof(pbuf) - 1, stop - off);
		if (skb_copy_bits(skb, off, pbuf, len))
			break;
		pbuf[len] = '\0';

		port = htons(simple_strtoul(pbuf, &tmp, 10));
		len = tmp - pbuf;
		if (port == 0 || len > 5)
			break;

		exp = nf_ct_expect_alloc(ct);
		if (exp == NULL) {
			ret = NF_DROP;
			goto out;
		}
		tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
		nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT,
				  nf_ct_l3num(ct),
				  &tuple->src.u3, &tuple->dst.u3,
				  IPPROTO_TCP, NULL, &port);

		nf_nat_amanda = rcu_dereference(nf_nat_amanda_hook);
		if (nf_nat_amanda && ct->status & IPS_NAT_MASK)
			ret = nf_nat_amanda(skb, ctinfo, off - dataoff,
					    len, exp);
		else if (nf_ct_expect_related(exp) != 0)
			ret = NF_DROP;
		nf_ct_expect_put(exp);
	}

out:
	return ret;
}

static const struct nf_conntrack_expect_policy amanda_exp_policy = {
	.max_expected		= 3,
	.timeout		= 180,
};

static struct nf_conntrack_helper amanda_helper[2] __read_mostly = {
	{
		.name			= "amanda",
		.me			= THIS_MODULE,
		.help			= amanda_help,
		.tuple.src.l3num	= AF_INET,
		.tuple.src.u.udp.port	= cpu_to_be16(10080),
		.tuple.dst.protonum	= IPPROTO_UDP,
		.expect_policy		= &amanda_exp_policy,
	},
	{
		.name			= "amanda",
		.me			= THIS_MODULE,
		.help			= amanda_help,
		.tuple.src.l3num	= AF_INET6,
		.tuple.src.u.udp.port	= cpu_to_be16(10080),
		.tuple.dst.protonum	= IPPROTO_UDP,
		.expect_policy		= &amanda_exp_policy,
	},
};

static void __exit nf_conntrack_amanda_fini(void)
{
	int i;

	nf_conntrack_helper_unregister(&amanda_helper[0]);
	nf_conntrack_helper_unregister(&amanda_helper[1]);
	for (i = 0; i < ARRAY_SIZE(search); i++)
		textsearch_destroy(search[i].ts);
}

static int __init nf_conntrack_amanda_init(void)
{
	int ret, i;

	for (i = 0; i < ARRAY_SIZE(search); i++) {
		search[i].ts = textsearch_prepare(ts_algo, search[i].string,
						  search[i].len,
						  GFP_KERNEL, TS_AUTOLOAD);
		if (IS_ERR(search[i].ts)) {
			ret = PTR_ERR(search[i].ts);
			goto err1;
		}
	}
	ret = nf_conntrack_helper_register(&amanda_helper[0]);
	if (ret < 0)
		goto err1;
	ret = nf_conntrack_helper_register(&amanda_helper[1]);
	if (ret < 0)
		goto err2;
	return 0;

err2:
	nf_conntrack_helper_unregister(&amanda_helper[0]);
err1:
	while (--i >= 0)
		textsearch_destroy(search[i].ts);

	return ret;
}

module_init(nf_conntrack_amanda_init);
module_exit(nf_conntrack_amanda_fini);
Commit	Line	Data
16958900 PM	1	/* Amanda extension for IP connection tracking
	2	*
	3	* (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca>
	4	* based on HW's ip_conntrack_irc.c as well as other modules
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11	#include <linux/kernel.h>
	12	#include <linux/module.h>
	13	#include <linux/moduleparam.h>
	14	#include <linux/textsearch.h>
	15	#include <linux/skbuff.h>
	16	#include <linux/in.h>
	17	#include <linux/udp.h>
1863f096	18	#include <linux/netfilter.h>
5a0e3ad6	19	#include <linux/gfp.h>
16958900 PM	20
	21	#include <net/netfilter/nf_conntrack.h>
	22	#include <net/netfilter/nf_conntrack_expect.h>
	23	#include <net/netfilter/nf_conntrack_ecache.h>
	24	#include <net/netfilter/nf_conntrack_helper.h>
	25	#include <linux/netfilter/nf_conntrack_amanda.h>
	26
	27	static unsigned int master_timeout __read_mostly = 300;
	28	static char *ts_algo = "kmp";
	29
	30	MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");
	31	MODULE_DESCRIPTION("Amanda connection tracking module");
	32	MODULE_LICENSE("GPL");
	33	MODULE_ALIAS("ip_conntrack_amanda");
4dc06f96	34	MODULE_ALIAS_NFCT_HELPER("amanda");
16958900 PM	35
	36	module_param(master_timeout, uint, 0600);
	37	MODULE_PARM_DESC(master_timeout, "timeout for the master connection");
	38	module_param(ts_algo, charp, 0400);
	39	MODULE_PARM_DESC(ts_algo, "textsearch algorithm to use (default kmp)");
	40
3db05fea	41	unsigned int (nf_nat_amanda_hook)(struct sk_buff skb,
16958900 PM	42	enum ip_conntrack_info ctinfo,
	43	unsigned int matchoff,
	44	unsigned int matchlen,
	45	struct nf_conntrack_expect *exp)
	46	__read_mostly;
	47	EXPORT_SYMBOL_GPL(nf_nat_amanda_hook);
	48
	49	enum amanda_strings {
	50	SEARCH_CONNECT,
	51	SEARCH_NEWLINE,
	52	SEARCH_DATA,
	53	SEARCH_MESG,
	54	SEARCH_INDEX,
	55	};
	56
	57	static struct {
58c0fb0d	58	const char *string;
16958900 PM	59	size_t len;
	60	struct ts_config *ts;
	61	} search[] __read_mostly = {
	62	[SEARCH_CONNECT] = {
	63	.string = "CONNECT ",
	64	.len = 8,
	65	},
	66	[SEARCH_NEWLINE] = {
	67	.string = "\n",
	68	.len = 1,
	69	},
	70	[SEARCH_DATA] = {
	71	.string = "DATA ",
	72	.len = 5,
	73	},
	74	[SEARCH_MESG] = {
	75	.string = "MESG ",
	76	.len = 5,
	77	},
	78	[SEARCH_INDEX] = {
	79	.string = "INDEX ",
	80	.len = 6,
	81	},
	82	};
	83
3db05fea	84	static int amanda_help(struct sk_buff *skb,
16958900 PM	85	unsigned int protoff,
	86	struct nf_conn *ct,
	87	enum ip_conntrack_info ctinfo)
	88	{
	89	struct ts_state ts;
	90	struct nf_conntrack_expect *exp;
	91	struct nf_conntrack_tuple *tuple;
	92	unsigned int dataoff, start, stop, off, i;
	93	char pbuf[sizeof("65535")], *tmp;
	94	u_int16_t len;
	95	__be16 port;
16958900 PM	96	int ret = NF_ACCEPT;
	97	typeof(nf_nat_amanda_hook) nf_nat_amanda;
	98
	99	/* Only look at packets from the Amanda server */
	100	if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
	101	return NF_ACCEPT;
	102
	103	/* increase the UDP timeout of the master connection as replies from
	104	* Amanda clients to the server can be quite delayed */
3db05fea	105	nf_ct_refresh(ct, skb, master_timeout * HZ);
16958900 PM	106
	107	/* No data? */
	108	dataoff = protoff + sizeof(struct udphdr);
3db05fea	109	if (dataoff >= skb->len) {
16958900	110	if (net_ratelimit())
654d0fbd	111	printk(KERN_ERR "amanda_help: skblen = %u\n", skb->len);
16958900 PM	112	return NF_ACCEPT;
	113	}
	114
	115	memset(&ts, 0, sizeof(ts));
3db05fea	116	start = skb_find_text(skb, dataoff, skb->len,
16958900 PM	117	search[SEARCH_CONNECT].ts, &ts);
	118	if (start == UINT_MAX)
	119	goto out;
	120	start += dataoff + search[SEARCH_CONNECT].len;
	121
	122	memset(&ts, 0, sizeof(ts));
3db05fea	123	stop = skb_find_text(skb, start, skb->len,
16958900 PM	124	search[SEARCH_NEWLINE].ts, &ts);
	125	if (stop == UINT_MAX)
	126	goto out;
	127	stop += start;
	128
	129	for (i = SEARCH_DATA; i <= SEARCH_INDEX; i++) {
	130	memset(&ts, 0, sizeof(ts));
3db05fea	131	off = skb_find_text(skb, start, stop, search[i].ts, &ts);
16958900 PM	132	if (off == UINT_MAX)
	133	continue;
	134	off += start + search[i].len;
	135
	136	len = min_t(unsigned int, sizeof(pbuf) - 1, stop - off);
3db05fea	137	if (skb_copy_bits(skb, off, pbuf, len))
16958900 PM	138	break;
	139	pbuf[len] = '\0';
	140
	141	port = htons(simple_strtoul(pbuf, &tmp, 10));
	142	len = tmp - pbuf;
	143	if (port == 0 \|\| len > 5)
	144	break;
	145
6823645d	146	exp = nf_ct_expect_alloc(ct);
16958900 PM	147	if (exp == NULL) {
	148	ret = NF_DROP;
	149	goto out;
	150	}
	151	tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
5e8fbe2a PM	152	nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT,
5e8fbe2a PM	153	nf_ct_l3num(ct),
6002f266	154	&tuple->src.u3, &tuple->dst.u3,
6823645d	155	IPPROTO_TCP, NULL, &port);
16958900 PM	156
	157	nf_nat_amanda = rcu_dereference(nf_nat_amanda_hook);
	158	if (nf_nat_amanda && ct->status & IPS_NAT_MASK)
3db05fea	159	ret = nf_nat_amanda(skb, ctinfo, off - dataoff,
16958900	160	len, exp);
6823645d	161	else if (nf_ct_expect_related(exp) != 0)
16958900	162	ret = NF_DROP;
6823645d	163	nf_ct_expect_put(exp);
16958900 PM	164	}
	165
	166	out:
	167	return ret;
	168	}
	169
6002f266 PM	170	static const struct nf_conntrack_expect_policy amanda_exp_policy = {
	171	.max_expected = 3,
	172	.timeout = 180,
	173	};
	174
16958900 PM	175	static struct nf_conntrack_helper amanda_helper[2] __read_mostly = {
	176	{
	177	.name = "amanda",
16958900 PM	178	.me = THIS_MODULE,
	179	.help = amanda_help,
	180	.tuple.src.l3num = AF_INET,
09640e63	181	.tuple.src.u.udp.port = cpu_to_be16(10080),
16958900	182	.tuple.dst.protonum = IPPROTO_UDP,
6002f266	183	.expect_policy = &amanda_exp_policy,
16958900 PM	184	},
	185	{
	186	.name = "amanda",
16958900 PM	187	.me = THIS_MODULE,
	188	.help = amanda_help,
	189	.tuple.src.l3num = AF_INET6,
09640e63	190	.tuple.src.u.udp.port = cpu_to_be16(10080),
16958900	191	.tuple.dst.protonum = IPPROTO_UDP,
6002f266	192	.expect_policy = &amanda_exp_policy,
16958900 PM	193	},
	194	};
	195
	196	static void __exit nf_conntrack_amanda_fini(void)
	197	{
	198	int i;
	199
	200	nf_conntrack_helper_unregister(&amanda_helper[0]);
	201	nf_conntrack_helper_unregister(&amanda_helper[1]);
	202	for (i = 0; i < ARRAY_SIZE(search); i++)
	203	textsearch_destroy(search[i].ts);
	204	}
	205
	206	static int __init nf_conntrack_amanda_init(void)
	207	{
	208	int ret, i;
	209
16958900 PM	210	for (i = 0; i < ARRAY_SIZE(search); i++) {
	211	search[i].ts = textsearch_prepare(ts_algo, search[i].string,
	212	search[i].len,
	213	GFP_KERNEL, TS_AUTOLOAD);
c764c9ad AM	214	if (IS_ERR(search[i].ts)) {
c764c9ad AM	215	ret = PTR_ERR(search[i].ts);
16958900	216	goto err1;
c764c9ad	217	}
16958900 PM	218	}
	219	ret = nf_conntrack_helper_register(&amanda_helper[0]);
	220	if (ret < 0)
	221	goto err1;
	222	ret = nf_conntrack_helper_register(&amanda_helper[1]);
	223	if (ret < 0)
	224	goto err2;
	225	return 0;
	226
	227	err2:
	228	nf_conntrack_helper_unregister(&amanda_helper[0]);
	229	err1:
c764c9ad AM	230	while (--i >= 0)
	231	textsearch_destroy(search[i].ts);
	232
16958900 PM	233	return ret;
	234	}
	235
	236	module_init(nf_conntrack_amanda_init);
	237	module_exit(nf_conntrack_amanda_fini);