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

/* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/in.h>
#include <linux/udp.h>
#include <linux/netfilter.h>

#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_tuple.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_tftp.h>

MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");
MODULE_DESCRIPTION("TFTP connection tracking helper");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ip_conntrack_tftp");

#define MAX_PORTS 8
static unsigned short ports[MAX_PORTS];
static unsigned int ports_c;
module_param_array(ports, ushort, &ports_c, 0400);
MODULE_PARM_DESC(ports, "Port numbers of TFTP servers");

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

static int tftp_help(struct sk_buff *skb,
		     unsigned int protoff,
		     struct nf_conn *ct,
		     enum ip_conntrack_info ctinfo)
{
	const struct tftphdr *tfh;
	struct tftphdr _tftph;
	struct nf_conntrack_expect *exp;
	struct nf_conntrack_tuple *tuple;
	unsigned int ret = NF_ACCEPT;
	typeof(nf_nat_tftp_hook) nf_nat_tftp;

	tfh = skb_header_pointer(skb, protoff + sizeof(struct udphdr),
				 sizeof(_tftph), &_tftph);
	if (tfh == NULL)
		return NF_ACCEPT;

	switch (ntohs(tfh->opcode)) {
	case TFTP_OPCODE_READ:
	case TFTP_OPCODE_WRITE:
		/* RRQ and WRQ works the same way */
		nf_ct_dump_tuple(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
		nf_ct_dump_tuple(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);

		exp = nf_ct_expect_alloc(ct);
		if (exp == NULL)
			return NF_DROP;
		tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
		nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT,
				  nf_ct_l3num(ct),
				  &tuple->src.u3, &tuple->dst.u3,
				  IPPROTO_UDP, NULL, &tuple->dst.u.udp.port);

		pr_debug("expect: ");
		nf_ct_dump_tuple(&exp->tuple);

		nf_nat_tftp = rcu_dereference(nf_nat_tftp_hook);
		if (nf_nat_tftp && ct->status & IPS_NAT_MASK)
			ret = nf_nat_tftp(skb, ctinfo, exp);
		else if (nf_ct_expect_related(exp) != 0)
			ret = NF_DROP;
		nf_ct_expect_put(exp);
		break;
	case TFTP_OPCODE_DATA:
	case TFTP_OPCODE_ACK:
		pr_debug("Data/ACK opcode\n");
		break;
	case TFTP_OPCODE_ERROR:
		pr_debug("Error opcode\n");
		break;
	default:
		pr_debug("Unknown opcode\n");
	}
	return ret;
}

static struct nf_conntrack_helper tftp[MAX_PORTS][2] __read_mostly;
static char tftp_names[MAX_PORTS][2][sizeof("tftp-65535")] __read_mostly;

static const struct nf_conntrack_expect_policy tftp_exp_policy = {
	.max_expected	= 1,
	.timeout	= 5 * 60,
};

static void nf_conntrack_tftp_fini(void)
{
	int i, j;

	for (i = 0; i < ports_c; i++) {
		for (j = 0; j < 2; j++)
			nf_conntrack_helper_unregister(&tftp[i][j]);
	}
}

static int __init nf_conntrack_tftp_init(void)
{
	int i, j, ret;
	char *tmpname;

	if (ports_c == 0)
		ports[ports_c++] = TFTP_PORT;

	for (i = 0; i < ports_c; i++) {
		memset(&tftp[i], 0, sizeof(tftp[i]));

		tftp[i][0].tuple.src.l3num = AF_INET;
		tftp[i][1].tuple.src.l3num = AF_INET6;
		for (j = 0; j < 2; j++) {
			tftp[i][j].tuple.dst.protonum = IPPROTO_UDP;
			tftp[i][j].tuple.src.u.udp.port = htons(ports[i]);
			tftp[i][j].expect_policy = &tftp_exp_policy;
			tftp[i][j].me = THIS_MODULE;
			tftp[i][j].help = tftp_help;

			tmpname = &tftp_names[i][j][0];
			if (ports[i] == TFTP_PORT)
				sprintf(tmpname, "tftp");
			else
				sprintf(tmpname, "tftp-%u", i);
			tftp[i][j].name = tmpname;

			ret = nf_conntrack_helper_register(&tftp[i][j]);
			if (ret) {
				printk("nf_ct_tftp: failed to register helper "
				       "for pf: %u port: %u\n",
					tftp[i][j].tuple.src.l3num, ports[i]);
				nf_conntrack_tftp_fini();
				return ret;
			}
		}
	}
	return 0;
}

module_init(nf_conntrack_tftp_init);
module_exit(nf_conntrack_tftp_fini);
Commit	Line	Data
a536df35 PM	1	/* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu>
	2	*
	3	* This program is free software; you can redistribute it and/or modify
	4	* it under the terms of the GNU General Public License version 2 as
	5	* published by the Free Software Foundation.
	6	*/
	7
	8	#include <linux/module.h>
	9	#include <linux/moduleparam.h>
	10	#include <linux/in.h>
	11	#include <linux/udp.h>
1863f096	12	#include <linux/netfilter.h>
a536df35 PM	13
	14	#include <net/netfilter/nf_conntrack.h>
	15	#include <net/netfilter/nf_conntrack_tuple.h>
	16	#include <net/netfilter/nf_conntrack_expect.h>
	17	#include <net/netfilter/nf_conntrack_ecache.h>
	18	#include <net/netfilter/nf_conntrack_helper.h>
	19	#include <linux/netfilter/nf_conntrack_tftp.h>
	20
	21	MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");
	22	MODULE_DESCRIPTION("TFTP connection tracking helper");
	23	MODULE_LICENSE("GPL");
	24	MODULE_ALIAS("ip_conntrack_tftp");
	25
	26	#define MAX_PORTS 8
	27	static unsigned short ports[MAX_PORTS];
2f0d2f10	28	static unsigned int ports_c;
a536df35 PM	29	module_param_array(ports, ushort, &ports_c, 0400);
	30	MODULE_PARM_DESC(ports, "Port numbers of TFTP servers");
	31
3db05fea	32	unsigned int (nf_nat_tftp_hook)(struct sk_buff skb,
a536df35 PM	33	enum ip_conntrack_info ctinfo,
	34	struct nf_conntrack_expect *exp) __read_mostly;
	35	EXPORT_SYMBOL_GPL(nf_nat_tftp_hook);
	36
3db05fea	37	static int tftp_help(struct sk_buff *skb,
a536df35 PM	38	unsigned int protoff,
	39	struct nf_conn *ct,
	40	enum ip_conntrack_info ctinfo)
	41	{
de24b4eb JE	42	const struct tftphdr *tfh;
de24b4eb JE	43	struct tftphdr _tftph;
a536df35 PM	44	struct nf_conntrack_expect *exp;
	45	struct nf_conntrack_tuple *tuple;
	46	unsigned int ret = NF_ACCEPT;
a536df35 PM	47	typeof(nf_nat_tftp_hook) nf_nat_tftp;
a536df35 PM	48
3db05fea	49	tfh = skb_header_pointer(skb, protoff + sizeof(struct udphdr),
a536df35 PM	50	sizeof(_tftph), &_tftph);
	51	if (tfh == NULL)
	52	return NF_ACCEPT;
	53
	54	switch (ntohs(tfh->opcode)) {
	55	case TFTP_OPCODE_READ:
	56	case TFTP_OPCODE_WRITE:
	57	/* RRQ and WRQ works the same way */
3c9fba65 JE	58	nf_ct_dump_tuple(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
3c9fba65 JE	59	nf_ct_dump_tuple(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
a536df35	60
6823645d	61	exp = nf_ct_expect_alloc(ct);
a536df35 PM	62	if (exp == NULL)
	63	return NF_DROP;
	64	tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
5e8fbe2a PM	65	nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT,
5e8fbe2a PM	66	nf_ct_l3num(ct),
6002f266	67	&tuple->src.u3, &tuple->dst.u3,
6823645d	68	IPPROTO_UDP, NULL, &tuple->dst.u.udp.port);
a536df35	69
0d53778e	70	pr_debug("expect: ");
3c9fba65	71	nf_ct_dump_tuple(&exp->tuple);
a536df35 PM	72
	73	nf_nat_tftp = rcu_dereference(nf_nat_tftp_hook);
	74	if (nf_nat_tftp && ct->status & IPS_NAT_MASK)
3db05fea	75	ret = nf_nat_tftp(skb, ctinfo, exp);
6823645d	76	else if (nf_ct_expect_related(exp) != 0)
a536df35	77	ret = NF_DROP;
6823645d	78	nf_ct_expect_put(exp);
a536df35 PM	79	break;
	80	case TFTP_OPCODE_DATA:
	81	case TFTP_OPCODE_ACK:
0d53778e	82	pr_debug("Data/ACK opcode\n");
a536df35 PM	83	break;
a536df35 PM	84	case TFTP_OPCODE_ERROR:
0d53778e	85	pr_debug("Error opcode\n");
a536df35 PM	86	break;
a536df35 PM	87	default:
0d53778e	88	pr_debug("Unknown opcode\n");
a536df35 PM	89	}
	90	return ret;
	91	}
	92
	93	static struct nf_conntrack_helper tftp[MAX_PORTS][2] __read_mostly;
	94	static char tftp_names[MAX_PORTS][2][sizeof("tftp-65535")] __read_mostly;
	95
6002f266 PM	96	static const struct nf_conntrack_expect_policy tftp_exp_policy = {
	97	.max_expected = 1,
	98	.timeout = 5 * 60,
	99	};
	100
a536df35 PM	101	static void nf_conntrack_tftp_fini(void)
	102	{
	103	int i, j;
	104
	105	for (i = 0; i < ports_c; i++) {
	106	for (j = 0; j < 2; j++)
	107	nf_conntrack_helper_unregister(&tftp[i][j]);
	108	}
	109	}
	110
	111	static int __init nf_conntrack_tftp_init(void)
	112	{
	113	int i, j, ret;
	114	char *tmpname;
	115
	116	if (ports_c == 0)
	117	ports[ports_c++] = TFTP_PORT;
	118
	119	for (i = 0; i < ports_c; i++) {
	120	memset(&tftp[i], 0, sizeof(tftp[i]));
	121
	122	tftp[i][0].tuple.src.l3num = AF_INET;
	123	tftp[i][1].tuple.src.l3num = AF_INET6;
	124	for (j = 0; j < 2; j++) {
	125	tftp[i][j].tuple.dst.protonum = IPPROTO_UDP;
	126	tftp[i][j].tuple.src.u.udp.port = htons(ports[i]);
6002f266	127	tftp[i][j].expect_policy = &tftp_exp_policy;
a536df35 PM	128	tftp[i][j].me = THIS_MODULE;
	129	tftp[i][j].help = tftp_help;
	130
	131	tmpname = &tftp_names[i][j][0];
	132	if (ports[i] == TFTP_PORT)
	133	sprintf(tmpname, "tftp");
	134	else
	135	sprintf(tmpname, "tftp-%u", i);
	136	tftp[i][j].name = tmpname;
	137
	138	ret = nf_conntrack_helper_register(&tftp[i][j]);
	139	if (ret) {
	140	printk("nf_ct_tftp: failed to register helper "
	141	"for pf: %u port: %u\n",
	142	tftp[i][j].tuple.src.l3num, ports[i]);
	143	nf_conntrack_tftp_fini();
	144	return ret;
	145	}
	146	}
	147	}
	148	return 0;
	149	}
	150
	151	module_init(nf_conntrack_tftp_init);
	152	module_exit(nf_conntrack_tftp_fini);