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

/* (C) 1999-2001 Paul `Rusty' Russell
 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
 * (C) 2007 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 version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/types.h>
#include <linux/timer.h>
#include <linux/module.h>
#include <linux/udp.h>
#include <linux/seq_file.h>
#include <linux/skbuff.h>
#include <linux/ipv6.h>
#include <net/ip6_checksum.h>
#include <net/checksum.h>

#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#include <net/netfilter/nf_log.h>

static unsigned int nf_ct_udplite_timeout __read_mostly = 30*HZ;
static unsigned int nf_ct_udplite_timeout_stream __read_mostly = 180*HZ;

static int udplite_pkt_to_tuple(const struct sk_buff *skb,
				unsigned int dataoff,
				struct nf_conntrack_tuple *tuple)
{
	struct udphdr _hdr, *hp;

	hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
	if (hp == NULL)
		return 0;

	tuple->src.u.udp.port = hp->source;
	tuple->dst.u.udp.port = hp->dest;
	return 1;
}

static int udplite_invert_tuple(struct nf_conntrack_tuple *tuple,
				const struct nf_conntrack_tuple *orig)
{
	tuple->src.u.udp.port = orig->dst.u.udp.port;
	tuple->dst.u.udp.port = orig->src.u.udp.port;
	return 1;
}

/* Print out the per-protocol part of the tuple. */
static int udplite_print_tuple(struct seq_file *s,
			       const struct nf_conntrack_tuple *tuple)
{
	return seq_printf(s, "sport=%hu dport=%hu ",
			  ntohs(tuple->src.u.udp.port),
			  ntohs(tuple->dst.u.udp.port));
}

/* Returns verdict for packet, and may modify conntracktype */
static int udplite_packet(struct nf_conn *ct,
			  const struct sk_buff *skb,
			  unsigned int dataoff,
			  enum ip_conntrack_info ctinfo,
			  int pf,
			  unsigned int hooknum)
{
	/* If we've seen traffic both ways, this is some kind of UDP
	   stream.  Extend timeout. */
	if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
		nf_ct_refresh_acct(ct, ctinfo, skb,
				   nf_ct_udplite_timeout_stream);
		/* Also, more likely to be important, and not a probe */
		if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
			nf_conntrack_event_cache(IPCT_STATUS, skb);
	} else
		nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_udplite_timeout);

	return NF_ACCEPT;
}

/* Called when a new connection for this protocol found. */
static int udplite_new(struct nf_conn *ct, const struct sk_buff *skb,
		       unsigned int dataoff)
{
	return 1;
}

static int udplite_error(struct sk_buff *skb, unsigned int dataoff,
			 enum ip_conntrack_info *ctinfo,
			 int pf,
			 unsigned int hooknum)
{
	unsigned int udplen = skb->len - dataoff;
	struct udphdr _hdr, *hdr;
	unsigned int cscov;

	/* Header is too small? */
	hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
	if (hdr == NULL) {
		if (LOG_INVALID(IPPROTO_UDPLITE))
			nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
				      "nf_ct_udplite: short packet ");
		return -NF_ACCEPT;
	}

	cscov = ntohs(hdr->len);
	if (cscov == 0)
		cscov = udplen;
	else if (cscov < sizeof(*hdr) || cscov > udplen) {
		if (LOG_INVALID(IPPROTO_UDPLITE))
			nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
				"nf_ct_udplite: invalid checksum coverage ");
		return -NF_ACCEPT;
	}

	/* UDPLITE mandates checksums */
	if (!hdr->check) {
		if (LOG_INVALID(IPPROTO_UDPLITE))
			nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
				      "nf_ct_udplite: checksum missing ");
		return -NF_ACCEPT;
	}

	/* Checksum invalid? Ignore. */
	if (nf_conntrack_checksum && !skb_csum_unnecessary(skb) &&
	    hooknum == NF_INET_PRE_ROUTING) {
		if (pf == PF_INET) {
			struct iphdr *iph = ip_hdr(skb);

			skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
						       udplen, IPPROTO_UDPLITE, 0);
		} else {
			struct ipv6hdr *ipv6h = ipv6_hdr(skb);
			__wsum hsum = skb_checksum(skb, 0, dataoff, 0);

			skb->csum = ~csum_unfold(
				csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
						udplen, IPPROTO_UDPLITE,
						csum_sub(0, hsum)));
		}

		skb->ip_summed = CHECKSUM_NONE;
		if (__skb_checksum_complete_head(skb, dataoff + cscov)) {
			if (LOG_INVALID(IPPROTO_UDPLITE))
				nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
					      "nf_ct_udplite: bad UDPLite "
					      "checksum ");
			return -NF_ACCEPT;
		}
		skb->ip_summed = CHECKSUM_UNNECESSARY;
	}

	return NF_ACCEPT;
}

#ifdef CONFIG_SYSCTL
static unsigned int udplite_sysctl_table_users;
static struct ctl_table_header *udplite_sysctl_header;
static struct ctl_table udplite_sysctl_table[] = {
	{
		.ctl_name	= CTL_UNNUMBERED,
		.procname	= "nf_conntrack_udplite_timeout",
		.data		= &nf_ct_udplite_timeout,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
	},
	{
		.ctl_name	= CTL_UNNUMBERED,
		.procname	= "nf_conntrack_udplite_timeout_stream",
		.data		= &nf_ct_udplite_timeout_stream,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
	},
	{
		.ctl_name	= 0
	}
};
#endif /* CONFIG_SYSCTL */

static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite4 __read_mostly =
{
	.l3proto		= PF_INET,
	.l4proto		= IPPROTO_UDPLITE,
	.name			= "udplite",
	.pkt_to_tuple		= udplite_pkt_to_tuple,
	.invert_tuple		= udplite_invert_tuple,
	.print_tuple		= udplite_print_tuple,
	.packet			= udplite_packet,
	.new			= udplite_new,
	.error			= udplite_error,
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
	.tuple_to_nlattr	= nf_ct_port_tuple_to_nlattr,
	.nlattr_to_tuple	= nf_ct_port_nlattr_to_tuple,
	.nla_policy		= nf_ct_port_nla_policy,
#endif
#ifdef CONFIG_SYSCTL
	.ctl_table_users	= &udplite_sysctl_table_users,
	.ctl_table_header	= &udplite_sysctl_header,
	.ctl_table		= udplite_sysctl_table,
#endif
};

static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 __read_mostly =
{
	.l3proto		= PF_INET6,
	.l4proto		= IPPROTO_UDPLITE,
	.name			= "udplite",
	.pkt_to_tuple		= udplite_pkt_to_tuple,
	.invert_tuple		= udplite_invert_tuple,
	.print_tuple		= udplite_print_tuple,
	.packet			= udplite_packet,
	.new			= udplite_new,
	.error			= udplite_error,
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
	.tuple_to_nlattr	= nf_ct_port_tuple_to_nlattr,
	.nlattr_to_tuple	= nf_ct_port_nlattr_to_tuple,
	.nla_policy		= nf_ct_port_nla_policy,
#endif
#ifdef CONFIG_SYSCTL
	.ctl_table_users	= &udplite_sysctl_table_users,
	.ctl_table_header	= &udplite_sysctl_header,
	.ctl_table		= udplite_sysctl_table,
#endif
};

static int __init nf_conntrack_proto_udplite_init(void)
{
	int err;

	err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite4);
	if (err < 0)
		goto err1;
	err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite6);
	if (err < 0)
		goto err2;
	return 0;
err2:
	nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
err1:
	return err;
}

static void __exit nf_conntrack_proto_udplite_exit(void)
{
	nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite6);
	nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
}

module_init(nf_conntrack_proto_udplite_init);
module_exit(nf_conntrack_proto_udplite_exit);

MODULE_LICENSE("GPL");
Commit	Line	Data
59eecdfb PM	1	/* (C) 1999-2001 Paul `Rusty' Russell
	2	* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
	3	* (C) 2007 Patrick McHardy <kaber@trash.net>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License version 2 as
	7	* published by the Free Software Foundation.
	8	*/
	9
	10	#include <linux/types.h>
	11	#include <linux/timer.h>
	12	#include <linux/module.h>
59eecdfb PM	13	#include <linux/udp.h>
	14	#include <linux/seq_file.h>
	15	#include <linux/skbuff.h>
	16	#include <linux/ipv6.h>
	17	#include <net/ip6_checksum.h>
	18	#include <net/checksum.h>
	19
	20	#include <linux/netfilter.h>
	21	#include <linux/netfilter_ipv4.h>
	22	#include <linux/netfilter_ipv6.h>
	23	#include <net/netfilter/nf_conntrack_l4proto.h>
	24	#include <net/netfilter/nf_conntrack_ecache.h>
f01ffbd6	25	#include <net/netfilter/nf_log.h>
59eecdfb PM	26
	27	static unsigned int nf_ct_udplite_timeout __read_mostly = 30*HZ;
	28	static unsigned int nf_ct_udplite_timeout_stream __read_mostly = 180*HZ;
	29
	30	static int udplite_pkt_to_tuple(const struct sk_buff *skb,
	31	unsigned int dataoff,
	32	struct nf_conntrack_tuple *tuple)
	33	{
	34	struct udphdr _hdr, *hp;
	35
	36	hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
	37	if (hp == NULL)
	38	return 0;
	39
	40	tuple->src.u.udp.port = hp->source;
	41	tuple->dst.u.udp.port = hp->dest;
	42	return 1;
	43	}
	44
	45	static int udplite_invert_tuple(struct nf_conntrack_tuple *tuple,
	46	const struct nf_conntrack_tuple *orig)
	47	{
	48	tuple->src.u.udp.port = orig->dst.u.udp.port;
	49	tuple->dst.u.udp.port = orig->src.u.udp.port;
	50	return 1;
	51	}
	52
	53	/* Print out the per-protocol part of the tuple. */
	54	static int udplite_print_tuple(struct seq_file *s,
	55	const struct nf_conntrack_tuple *tuple)
	56	{
	57	return seq_printf(s, "sport=%hu dport=%hu ",
	58	ntohs(tuple->src.u.udp.port),
	59	ntohs(tuple->dst.u.udp.port));
	60	}
	61
59eecdfb	62	/* Returns verdict for packet, and may modify conntracktype */
c88130bc	63	static int udplite_packet(struct nf_conn *ct,
59eecdfb PM	64	const struct sk_buff *skb,
	65	unsigned int dataoff,
	66	enum ip_conntrack_info ctinfo,
	67	int pf,
	68	unsigned int hooknum)
	69	{
	70	/* If we've seen traffic both ways, this is some kind of UDP
	71	stream. Extend timeout. */
c88130bc PM	72	if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
c88130bc PM	73	nf_ct_refresh_acct(ct, ctinfo, skb,
59eecdfb PM	74	nf_ct_udplite_timeout_stream);
59eecdfb PM	75	/* Also, more likely to be important, and not a probe */
c88130bc	76	if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
59eecdfb PM	77	nf_conntrack_event_cache(IPCT_STATUS, skb);
59eecdfb PM	78	} else
c88130bc	79	nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_udplite_timeout);
59eecdfb PM	80
	81	return NF_ACCEPT;
	82	}
	83
	84	/* Called when a new connection for this protocol found. */
c88130bc	85	static int udplite_new(struct nf_conn ct, const struct sk_buff skb,
59eecdfb PM	86	unsigned int dataoff)
	87	{
	88	return 1;
	89	}
	90
	91	static int udplite_error(struct sk_buff *skb, unsigned int dataoff,
	92	enum ip_conntrack_info *ctinfo,
	93	int pf,
	94	unsigned int hooknum)
	95	{
	96	unsigned int udplen = skb->len - dataoff;
	97	struct udphdr _hdr, *hdr;
	98	unsigned int cscov;
	99
	100	/* Header is too small? */
	101	hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
	102	if (hdr == NULL) {
	103	if (LOG_INVALID(IPPROTO_UDPLITE))
	104	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
	105	"nf_ct_udplite: short packet ");
	106	return -NF_ACCEPT;
	107	}
	108
	109	cscov = ntohs(hdr->len);
	110	if (cscov == 0)
	111	cscov = udplen;
	112	else if (cscov < sizeof(*hdr) \|\| cscov > udplen) {
	113	if (LOG_INVALID(IPPROTO_UDPLITE))
	114	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
	115	"nf_ct_udplite: invalid checksum coverage ");
	116	return -NF_ACCEPT;
	117	}
	118
	119	/* UDPLITE mandates checksums */
	120	if (!hdr->check) {
	121	if (LOG_INVALID(IPPROTO_UDPLITE))
	122	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
	123	"nf_ct_udplite: checksum missing ");
	124	return -NF_ACCEPT;
	125	}
	126
	127	/* Checksum invalid? Ignore. */
	128	if (nf_conntrack_checksum && !skb_csum_unnecessary(skb) &&
6e23ae2a	129	hooknum == NF_INET_PRE_ROUTING) {
59eecdfb PM	130	if (pf == PF_INET) {
	131	struct iphdr *iph = ip_hdr(skb);
	132
	133	skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
	134	udplen, IPPROTO_UDPLITE, 0);
	135	} else {
	136	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
	137	__wsum hsum = skb_checksum(skb, 0, dataoff, 0);
	138
	139	skb->csum = ~csum_unfold(
	140	csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
	141	udplen, IPPROTO_UDPLITE,
	142	csum_sub(0, hsum)));
	143	}
	144
	145	skb->ip_summed = CHECKSUM_NONE;
	146	if (__skb_checksum_complete_head(skb, dataoff + cscov)) {
	147	if (LOG_INVALID(IPPROTO_UDPLITE))
	148	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
	149	"nf_ct_udplite: bad UDPLite "
	150	"checksum ");
	151	return -NF_ACCEPT;
	152	}
	153	skb->ip_summed = CHECKSUM_UNNECESSARY;
	154	}
	155
	156	return NF_ACCEPT;
	157	}
	158
	159	#ifdef CONFIG_SYSCTL
	160	static unsigned int udplite_sysctl_table_users;
	161	static struct ctl_table_header *udplite_sysctl_header;
	162	static struct ctl_table udplite_sysctl_table[] = {
	163	{
	164	.ctl_name = CTL_UNNUMBERED,
	165	.procname = "nf_conntrack_udplite_timeout",
	166	.data = &nf_ct_udplite_timeout,
	167	.maxlen = sizeof(unsigned int),
	168	.mode = 0644,
	169	.proc_handler = &proc_dointvec_jiffies,
	170	},
	171	{
	172	.ctl_name = CTL_UNNUMBERED,
	173	.procname = "nf_conntrack_udplite_timeout_stream",
	174	.data = &nf_ct_udplite_timeout_stream,
	175	.maxlen = sizeof(unsigned int),
	176	.mode = 0644,
	177	.proc_handler = &proc_dointvec_jiffies,
	178	},
	179	{
	180	.ctl_name = 0
	181	}
	182	};
	183	#endif /* CONFIG_SYSCTL */
	184
	185	static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite4 __read_mostly =
	186	{
	187	.l3proto = PF_INET,
	188	.l4proto = IPPROTO_UDPLITE,
	189	.name = "udplite",
	190	.pkt_to_tuple = udplite_pkt_to_tuple,
	191	.invert_tuple = udplite_invert_tuple,
	192	.print_tuple = udplite_print_tuple,
59eecdfb PM	193	.packet = udplite_packet,
	194	.new = udplite_new,
	195	.error = udplite_error,
	196	#if defined(CONFIG_NF_CT_NETLINK) \|\| defined(CONFIG_NF_CT_NETLINK_MODULE)
fdf70832 PM	197	.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
fdf70832 PM	198	.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
f73e924c	199	.nla_policy = nf_ct_port_nla_policy,
59eecdfb PM	200	#endif
	201	#ifdef CONFIG_SYSCTL
	202	.ctl_table_users = &udplite_sysctl_table_users,
	203	.ctl_table_header = &udplite_sysctl_header,
	204	.ctl_table = udplite_sysctl_table,
	205	#endif
	206	};
	207
	208	static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 __read_mostly =
	209	{
	210	.l3proto = PF_INET6,
	211	.l4proto = IPPROTO_UDPLITE,
	212	.name = "udplite",
	213	.pkt_to_tuple = udplite_pkt_to_tuple,
	214	.invert_tuple = udplite_invert_tuple,
	215	.print_tuple = udplite_print_tuple,
59eecdfb PM	216	.packet = udplite_packet,
	217	.new = udplite_new,
	218	.error = udplite_error,
	219	#if defined(CONFIG_NF_CT_NETLINK) \|\| defined(CONFIG_NF_CT_NETLINK_MODULE)
fdf70832 PM	220	.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
fdf70832 PM	221	.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
f73e924c	222	.nla_policy = nf_ct_port_nla_policy,
59eecdfb PM	223	#endif
	224	#ifdef CONFIG_SYSCTL
	225	.ctl_table_users = &udplite_sysctl_table_users,
	226	.ctl_table_header = &udplite_sysctl_header,
	227	.ctl_table = udplite_sysctl_table,
	228	#endif
	229	};
	230
	231	static int __init nf_conntrack_proto_udplite_init(void)
	232	{
	233	int err;
	234
	235	err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite4);
	236	if (err < 0)
	237	goto err1;
	238	err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite6);
	239	if (err < 0)
	240	goto err2;
	241	return 0;
	242	err2:
	243	nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
	244	err1:
	245	return err;
	246	}
	247
	248	static void __exit nf_conntrack_proto_udplite_exit(void)
	249	{
	250	nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite6);
	251	nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
	252	}
	253
	254	module_init(nf_conntrack_proto_udplite_init);
	255	module_exit(nf_conntrack_proto_udplite_exit);
	256
	257	MODULE_LICENSE("GPL");