[deliverable/linux.git] / net / ipv4 / netfilter / ip_conntrack_amanda.c

/* Amanda extension for IP connection tracking, Version 0.2
 * (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.
 *
 *	Module load syntax:
 * 	insmod ip_conntrack_amanda.o [master_timeout=n]
 *	
 *	Where master_timeout is the timeout (in seconds) of the master
 *	connection (port 10080).  This defaults to 5 minutes but if
 *	your clients take longer than 5 minutes to do their work
 *	before getting back to the Amanda server, you can increase
 *	this value.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netfilter.h>
#include <linux/ip.h>
#include <linux/moduleparam.h>
#include <net/checksum.h>
#include <net/udp.h>

#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
#include <linux/netfilter_ipv4/ip_conntrack_amanda.h>

static unsigned int master_timeout = 300;

MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");
MODULE_DESCRIPTION("Amanda connection tracking module");
MODULE_LICENSE("GPL");
module_param(master_timeout, int, 0600);
MODULE_PARM_DESC(master_timeout, "timeout for the master connection");

static const char *conns[] = { "DATA ", "MESG ", "INDEX " };

/* This is slow, but it's simple. --RR */
static char *amanda_buffer;
static DEFINE_SPINLOCK(amanda_buffer_lock);

unsigned int (*ip_nat_amanda_hook)(struct sk_buff **pskb,
				   enum ip_conntrack_info ctinfo,
				   unsigned int matchoff,
				   unsigned int matchlen,
				   struct ip_conntrack_expect *exp);
EXPORT_SYMBOL_GPL(ip_nat_amanda_hook);

static int help(struct sk_buff **pskb,
                struct ip_conntrack *ct, enum ip_conntrack_info ctinfo)
{
	struct ip_conntrack_expect *exp;
	char *data, *data_limit, *tmp;
	unsigned int dataoff, i;
	u_int16_t port, len;
	int ret = NF_ACCEPT;

	/* 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 */
	ip_ct_refresh(ct, *pskb, master_timeout * HZ);

	/* No data? */
	dataoff = (*pskb)->nh.iph->ihl*4 + sizeof(struct udphdr);
	if (dataoff >= (*pskb)->len) {
		if (net_ratelimit())
			printk("amanda_help: skblen = %u\n", (*pskb)->len);
		return NF_ACCEPT;
	}

	spin_lock_bh(&amanda_buffer_lock);
	skb_copy_bits(*pskb, dataoff, amanda_buffer, (*pskb)->len - dataoff);
	data = amanda_buffer;
	data_limit = amanda_buffer + (*pskb)->len - dataoff;
	*data_limit = '\0';

	/* Search for the CONNECT string */
	data = strstr(data, "CONNECT ");
	if (!data)
		goto out;
	data += strlen("CONNECT ");

	/* Only search first line. */	
	if ((tmp = strchr(data, '\n')))
		*tmp = '\0';

	for (i = 0; i < ARRAY_SIZE(conns); i++) {
		char *match = strstr(data, conns[i]);
		if (!match)
			continue;
		tmp = data = match + strlen(conns[i]);
		port = simple_strtoul(data, &data, 10);
		len = data - tmp;
		if (port == 0 || len > 5)
			break;

		exp = ip_conntrack_expect_alloc(ct);
		if (exp == NULL) {
			ret = NF_DROP;
			goto out;
		}

		exp->expectfn = NULL;
		exp->flags = 0;

		exp->tuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
		exp->tuple.src.u.tcp.port = 0;
		exp->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip;
		exp->tuple.dst.protonum = IPPROTO_TCP;
		exp->tuple.dst.u.tcp.port = htons(port);

		exp->mask.src.ip = 0xFFFFFFFF;
		exp->mask.src.u.tcp.port = 0;
		exp->mask.dst.ip = 0xFFFFFFFF;
		exp->mask.dst.protonum = 0xFF;
		exp->mask.dst.u.tcp.port = 0xFFFF;

		if (ip_nat_amanda_hook)
			ret = ip_nat_amanda_hook(pskb, ctinfo,
						 tmp - amanda_buffer,
						 len, exp);
		else if (ip_conntrack_expect_related(exp) != 0)
			ret = NF_DROP;
		ip_conntrack_expect_put(exp);
	}

out:
	spin_unlock_bh(&amanda_buffer_lock);
	return ret;
}

static struct ip_conntrack_helper amanda_helper = {
	.max_expected = ARRAY_SIZE(conns),
	.timeout = 180,
	.me = THIS_MODULE,
	.help = help,
	.name = "amanda",

	.tuple = { .src = { .u = { __constant_htons(10080) } },
		   .dst = { .protonum = IPPROTO_UDP },
	},
	.mask = { .src = { .u = { 0xFFFF } },
		 .dst = { .protonum = 0xFF },
	},
};

static void __exit fini(void)
{
	ip_conntrack_helper_unregister(&amanda_helper);
	kfree(amanda_buffer);
}

static int __init init(void)
{
	int ret;

	amanda_buffer = kmalloc(65536, GFP_KERNEL);
	if (!amanda_buffer)
		return -ENOMEM;

	ret = ip_conntrack_helper_register(&amanda_helper);
	if (ret < 0) {
		kfree(amanda_buffer);
		return ret;
	}
	return 0;


}

module_init(init);
module_exit(fini);
Commit	Line	Data
1da177e4 LT	1	/* Amanda extension for IP connection tracking, Version 0.2
	2	* (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca>
	3	* based on HW's ip_conntrack_irc.c as well as other modules
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License
	7	* as published by the Free Software Foundation; either version
	8	* 2 of the License, or (at your option) any later version.
	9	*
	10	* Module load syntax:
	11	* insmod ip_conntrack_amanda.o [master_timeout=n]
	12	*
	13	* Where master_timeout is the timeout (in seconds) of the master
	14	* connection (port 10080). This defaults to 5 minutes but if
	15	* your clients take longer than 5 minutes to do their work
	16	* before getting back to the Amanda server, you can increase
	17	* this value.
	18	*
	19	*/
	20
	21	#include <linux/kernel.h>
	22	#include <linux/module.h>
	23	#include <linux/netfilter.h>
	24	#include <linux/ip.h>
	25	#include <linux/moduleparam.h>
	26	#include <net/checksum.h>
	27	#include <net/udp.h>
	28
1da177e4 LT	29	#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
	30	#include <linux/netfilter_ipv4/ip_conntrack_amanda.h>
	31
	32	static unsigned int master_timeout = 300;
	33
	34	MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");
	35	MODULE_DESCRIPTION("Amanda connection tracking module");
	36	MODULE_LICENSE("GPL");
	37	module_param(master_timeout, int, 0600);
	38	MODULE_PARM_DESC(master_timeout, "timeout for the master connection");
	39
9b5b5cff	40	static const char *conns[] = { "DATA ", "MESG ", "INDEX " };
1da177e4 LT	41
1da177e4 LT	42	/* This is slow, but it's simple. --RR */
2669d63d	43	static char *amanda_buffer;
e45b1be8	44	static DEFINE_SPINLOCK(amanda_buffer_lock);
1da177e4 LT	45
	46	unsigned int (ip_nat_amanda_hook)(struct sk_buff *pskb,
	47	enum ip_conntrack_info ctinfo,
	48	unsigned int matchoff,
	49	unsigned int matchlen,
	50	struct ip_conntrack_expect *exp);
	51	EXPORT_SYMBOL_GPL(ip_nat_amanda_hook);
	52
	53	static int help(struct sk_buff **pskb,
	54	struct ip_conntrack *ct, enum ip_conntrack_info ctinfo)
	55	{
	56	struct ip_conntrack_expect *exp;
	57	char data, data_limit, *tmp;
	58	unsigned int dataoff, i;
	59	u_int16_t port, len;
	60	int ret = NF_ACCEPT;
	61
	62	/* Only look at packets from the Amanda server */
	63	if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
	64	return NF_ACCEPT;
	65
	66	/* increase the UDP timeout of the master connection as replies from
	67	* Amanda clients to the server can be quite delayed */
1dfbab59	68	ip_ct_refresh(ct, pskb, master_timeout HZ);
1da177e4 LT	69
	70	/* No data? */
	71	dataoff = (pskb)->nh.iph->ihl4 + sizeof(struct udphdr);
	72	if (dataoff >= (*pskb)->len) {
	73	if (net_ratelimit())
	74	printk("amanda_help: skblen = %u\n", (*pskb)->len);
	75	return NF_ACCEPT;
	76	}
	77
e45b1be8	78	spin_lock_bh(&amanda_buffer_lock);
1da177e4 LT	79	skb_copy_bits(pskb, dataoff, amanda_buffer, (pskb)->len - dataoff);
	80	data = amanda_buffer;
	81	data_limit = amanda_buffer + (*pskb)->len - dataoff;
	82	*data_limit = '\0';
	83
	84	/* Search for the CONNECT string */
	85	data = strstr(data, "CONNECT ");
	86	if (!data)
	87	goto out;
	88	data += strlen("CONNECT ");
	89
	90	/* Only search first line. */
	91	if ((tmp = strchr(data, '\n')))
	92	*tmp = '\0';
	93
	94	for (i = 0; i < ARRAY_SIZE(conns); i++) {
	95	char *match = strstr(data, conns[i]);
	96	if (!match)
	97	continue;
	98	tmp = data = match + strlen(conns[i]);
	99	port = simple_strtoul(data, &data, 10);
	100	len = data - tmp;
	101	if (port == 0 \|\| len > 5)
	102	break;
	103
4acdbdbe	104	exp = ip_conntrack_expect_alloc(ct);
1da177e4 LT	105	if (exp == NULL) {
	106	ret = NF_DROP;
	107	goto out;
	108	}
	109
	110	exp->expectfn = NULL;
2248bcfc	111	exp->flags = 0;
1da177e4 LT	112
	113	exp->tuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
	114	exp->tuple.src.u.tcp.port = 0;
	115	exp->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip;
	116	exp->tuple.dst.protonum = IPPROTO_TCP;
	117	exp->tuple.dst.u.tcp.port = htons(port);
	118
	119	exp->mask.src.ip = 0xFFFFFFFF;
	120	exp->mask.src.u.tcp.port = 0;
	121	exp->mask.dst.ip = 0xFFFFFFFF;
	122	exp->mask.dst.protonum = 0xFF;
	123	exp->mask.dst.u.tcp.port = 0xFFFF;
	124
	125	if (ip_nat_amanda_hook)
	126	ret = ip_nat_amanda_hook(pskb, ctinfo,
	127	tmp - amanda_buffer,
	128	len, exp);
4acdbdbe	129	else if (ip_conntrack_expect_related(exp) != 0)
1da177e4	130	ret = NF_DROP;
4acdbdbe	131	ip_conntrack_expect_put(exp);
1da177e4 LT	132	}
	133
	134	out:
e45b1be8	135	spin_unlock_bh(&amanda_buffer_lock);
1da177e4 LT	136	return ret;
	137	}
	138
	139	static struct ip_conntrack_helper amanda_helper = {
	140	.max_expected = ARRAY_SIZE(conns),
	141	.timeout = 180,
	142	.me = THIS_MODULE,
	143	.help = help,
	144	.name = "amanda",
	145
	146	.tuple = { .src = { .u = { __constant_htons(10080) } },
	147	.dst = { .protonum = IPPROTO_UDP },
	148	},
	149	.mask = { .src = { .u = { 0xFFFF } },
	150	.dst = { .protonum = 0xFF },
	151	},
	152	};
	153
	154	static void __exit fini(void)
	155	{
	156	ip_conntrack_helper_unregister(&amanda_helper);
2669d63d	157	kfree(amanda_buffer);
1da177e4 LT	158	}
	159
	160	static int __init init(void)
	161	{
2669d63d HW	162	int ret;
	163
	164	amanda_buffer = kmalloc(65536, GFP_KERNEL);
	165	if (!amanda_buffer)
	166	return -ENOMEM;
	167
	168	ret = ip_conntrack_helper_register(&amanda_helper);
	169	if (ret < 0) {
	170	kfree(amanda_buffer);
	171	return ret;
	172	}
	173	return 0;
	174
	175
1da177e4 LT	176	}
	177
	178	module_init(init);
	179	module_exit(fini);