[GitHub/mt8127/android_kernel_alcatel_ttab.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
 * (C) 2006 Patrick McHardy <kaber@trash.net>
 *
 * 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 protoff,
				   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) {
		net_err_ratelimited("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) {
			nf_ct_helper_log(skb, ct, "cannot alloc expectation");
			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, protoff,
					    off - dataoff, len, exp);
		else if (nf_ct_expect_related(exp) != 0) {
			nf_ct_helper_log(skb, ct, "cannot add expectation");
			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
f229f6ce	5	* (C) 2006 Patrick McHardy <kaber@trash.net>
16958900 PM	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License
	9	* as published by the Free Software Foundation; either version
	10	* 2 of the License, or (at your option) any later version.
	11	*/
	12	#include <linux/kernel.h>
	13	#include <linux/module.h>
	14	#include <linux/moduleparam.h>
	15	#include <linux/textsearch.h>
	16	#include <linux/skbuff.h>
	17	#include <linux/in.h>
	18	#include <linux/udp.h>
1863f096	19	#include <linux/netfilter.h>
5a0e3ad6	20	#include <linux/gfp.h>
16958900 PM	21
	22	#include <net/netfilter/nf_conntrack.h>
	23	#include <net/netfilter/nf_conntrack_expect.h>
	24	#include <net/netfilter/nf_conntrack_ecache.h>
	25	#include <net/netfilter/nf_conntrack_helper.h>
	26	#include <linux/netfilter/nf_conntrack_amanda.h>
	27
	28	static unsigned int master_timeout __read_mostly = 300;
	29	static char *ts_algo = "kmp";
	30
	31	MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");
	32	MODULE_DESCRIPTION("Amanda connection tracking module");
	33	MODULE_LICENSE("GPL");
	34	MODULE_ALIAS("ip_conntrack_amanda");
4dc06f96	35	MODULE_ALIAS_NFCT_HELPER("amanda");
16958900 PM	36
	37	module_param(master_timeout, uint, 0600);
	38	MODULE_PARM_DESC(master_timeout, "timeout for the master connection");
	39	module_param(ts_algo, charp, 0400);
	40	MODULE_PARM_DESC(ts_algo, "textsearch algorithm to use (default kmp)");
	41
3db05fea	42	unsigned int (nf_nat_amanda_hook)(struct sk_buff skb,
16958900	43	enum ip_conntrack_info ctinfo,
051966c0	44	unsigned int protoff,
16958900 PM	45	unsigned int matchoff,
	46	unsigned int matchlen,
	47	struct nf_conntrack_expect *exp)
	48	__read_mostly;
	49	EXPORT_SYMBOL_GPL(nf_nat_amanda_hook);
	50
	51	enum amanda_strings {
	52	SEARCH_CONNECT,
	53	SEARCH_NEWLINE,
	54	SEARCH_DATA,
	55	SEARCH_MESG,
	56	SEARCH_INDEX,
	57	};
	58
	59	static struct {
58c0fb0d	60	const char *string;
16958900 PM	61	size_t len;
	62	struct ts_config *ts;
	63	} search[] __read_mostly = {
	64	[SEARCH_CONNECT] = {
	65	.string = "CONNECT ",
	66	.len = 8,
	67	},
	68	[SEARCH_NEWLINE] = {
	69	.string = "\n",
	70	.len = 1,
	71	},
	72	[SEARCH_DATA] = {
	73	.string = "DATA ",
	74	.len = 5,
	75	},
	76	[SEARCH_MESG] = {
	77	.string = "MESG ",
	78	.len = 5,
	79	},
	80	[SEARCH_INDEX] = {
	81	.string = "INDEX ",
	82	.len = 6,
	83	},
	84	};
	85
3db05fea	86	static int amanda_help(struct sk_buff *skb,
16958900 PM	87	unsigned int protoff,
	88	struct nf_conn *ct,
	89	enum ip_conntrack_info ctinfo)
	90	{
	91	struct ts_state ts;
	92	struct nf_conntrack_expect *exp;
	93	struct nf_conntrack_tuple *tuple;
	94	unsigned int dataoff, start, stop, off, i;
	95	char pbuf[sizeof("65535")], *tmp;
	96	u_int16_t len;
	97	__be16 port;
16958900 PM	98	int ret = NF_ACCEPT;
	99	typeof(nf_nat_amanda_hook) nf_nat_amanda;
	100
	101	/* Only look at packets from the Amanda server */
	102	if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
	103	return NF_ACCEPT;
	104
	105	/* increase the UDP timeout of the master connection as replies from
	106	* Amanda clients to the server can be quite delayed */
3db05fea	107	nf_ct_refresh(ct, skb, master_timeout * HZ);
16958900 PM	108
	109	/* No data? */
	110	dataoff = protoff + sizeof(struct udphdr);
3db05fea	111	if (dataoff >= skb->len) {
e87cc472	112	net_err_ratelimited("amanda_help: skblen = %u\n", skb->len);
16958900 PM	113	return NF_ACCEPT;
	114	}
	115
	116	memset(&ts, 0, sizeof(ts));
3db05fea	117	start = skb_find_text(skb, dataoff, skb->len,
16958900 PM	118	search[SEARCH_CONNECT].ts, &ts);
	119	if (start == UINT_MAX)
	120	goto out;
	121	start += dataoff + search[SEARCH_CONNECT].len;
	122
	123	memset(&ts, 0, sizeof(ts));
3db05fea	124	stop = skb_find_text(skb, start, skb->len,
16958900 PM	125	search[SEARCH_NEWLINE].ts, &ts);
	126	if (stop == UINT_MAX)
	127	goto out;
	128	stop += start;
	129
	130	for (i = SEARCH_DATA; i <= SEARCH_INDEX; i++) {
	131	memset(&ts, 0, sizeof(ts));
3db05fea	132	off = skb_find_text(skb, start, stop, search[i].ts, &ts);
16958900 PM	133	if (off == UINT_MAX)
	134	continue;
	135	off += start + search[i].len;
	136
	137	len = min_t(unsigned int, sizeof(pbuf) - 1, stop - off);
3db05fea	138	if (skb_copy_bits(skb, off, pbuf, len))
16958900 PM	139	break;
	140	pbuf[len] = '\0';
	141
	142	port = htons(simple_strtoul(pbuf, &tmp, 10));
	143	len = tmp - pbuf;
	144	if (port == 0 \|\| len > 5)
	145	break;
	146
6823645d	147	exp = nf_ct_expect_alloc(ct);
16958900	148	if (exp == NULL) {
b20ab9cc	149	nf_ct_helper_log(skb, ct, "cannot alloc expectation");
16958900 PM	150	ret = NF_DROP;
	151	goto out;
	152	}
	153	tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
5e8fbe2a PM	154	nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT,
5e8fbe2a PM	155	nf_ct_l3num(ct),
6002f266	156	&tuple->src.u3, &tuple->dst.u3,
6823645d	157	IPPROTO_TCP, NULL, &port);
16958900 PM	158
16958900 PM	159	nf_nat_amanda = rcu_dereference(nf_nat_amanda_hook);
ee6eb966	160	if (nf_nat_amanda && ct->status & IPS_NAT_MASK)
051966c0 PM	161	ret = nf_nat_amanda(skb, ctinfo, protoff,
051966c0 PM	162	off - dataoff, len, exp);
b20ab9cc PNA	163	else if (nf_ct_expect_related(exp) != 0) {
b20ab9cc PNA	164	nf_ct_helper_log(skb, ct, "cannot add expectation");
16958900	165	ret = NF_DROP;
b20ab9cc	166	}
6823645d	167	nf_ct_expect_put(exp);
16958900 PM	168	}
	169
	170	out:
	171	return ret;
	172	}
	173
6002f266 PM	174	static const struct nf_conntrack_expect_policy amanda_exp_policy = {
	175	.max_expected = 3,
	176	.timeout = 180,
	177	};
	178
16958900 PM	179	static struct nf_conntrack_helper amanda_helper[2] __read_mostly = {
	180	{
	181	.name = "amanda",
16958900 PM	182	.me = THIS_MODULE,
	183	.help = amanda_help,
	184	.tuple.src.l3num = AF_INET,
09640e63	185	.tuple.src.u.udp.port = cpu_to_be16(10080),
16958900	186	.tuple.dst.protonum = IPPROTO_UDP,
6002f266	187	.expect_policy = &amanda_exp_policy,
16958900 PM	188	},
	189	{
	190	.name = "amanda",
16958900 PM	191	.me = THIS_MODULE,
	192	.help = amanda_help,
	193	.tuple.src.l3num = AF_INET6,
09640e63	194	.tuple.src.u.udp.port = cpu_to_be16(10080),
16958900	195	.tuple.dst.protonum = IPPROTO_UDP,
6002f266	196	.expect_policy = &amanda_exp_policy,
16958900 PM	197	},
	198	};
	199
	200	static void __exit nf_conntrack_amanda_fini(void)
	201	{
	202	int i;
	203
	204	nf_conntrack_helper_unregister(&amanda_helper[0]);
	205	nf_conntrack_helper_unregister(&amanda_helper[1]);
	206	for (i = 0; i < ARRAY_SIZE(search); i++)
	207	textsearch_destroy(search[i].ts);
	208	}
	209
	210	static int __init nf_conntrack_amanda_init(void)
	211	{
	212	int ret, i;
	213
16958900 PM	214	for (i = 0; i < ARRAY_SIZE(search); i++) {
	215	search[i].ts = textsearch_prepare(ts_algo, search[i].string,
	216	search[i].len,
	217	GFP_KERNEL, TS_AUTOLOAD);
c764c9ad AM	218	if (IS_ERR(search[i].ts)) {
c764c9ad AM	219	ret = PTR_ERR(search[i].ts);
16958900	220	goto err1;
c764c9ad	221	}
16958900 PM	222	}
	223	ret = nf_conntrack_helper_register(&amanda_helper[0]);
	224	if (ret < 0)
	225	goto err1;
	226	ret = nf_conntrack_helper_register(&amanda_helper[1]);
	227	if (ret < 0)
	228	goto err2;
	229	return 0;
	230
	231	err2:
	232	nf_conntrack_helper_unregister(&amanda_helper[0]);
	233	err1:
c764c9ad AM	234	while (--i >= 0)
	235	textsearch_destroy(search[i].ts);
	236
16958900 PM	237	return ret;
	238	}
	239
	240	module_init(nf_conntrack_amanda_init);
	241	module_exit(nf_conntrack_amanda_fini);