[deliverable/linux.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/netfilter.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>

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));
}

/* Print out the private part of the conntrack. */
static int udplite_print_conntrack(struct seq_file *s,
				   const struct nf_conn *conntrack)
{
	return 0;
}

/* Returns verdict for packet, and may modify conntracktype */
static int udplite_packet(struct nf_conn *conntrack,
			  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, &conntrack->status)) {
		nf_ct_refresh_acct(conntrack, 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, &conntrack->status))
			nf_conntrack_event_cache(IPCT_STATUS, skb);
	} else
		nf_ct_refresh_acct(conntrack, 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 *conntrack, 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) &&
	    ((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) ||
	     (pf == PF_INET6 && hooknum == NF_IP6_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,
	.print_conntrack	= udplite_print_conntrack,
	.packet			= udplite_packet,
	.new			= udplite_new,
	.error			= udplite_error,
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
	.tuple_to_nfattr	= nf_ct_port_tuple_to_nfattr,
	.nfattr_to_tuple	= nf_ct_port_nfattr_to_tuple,
#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,
	.print_conntrack	= udplite_print_conntrack,
	.packet			= udplite_packet,
	.new			= udplite_new,
	.error			= udplite_error,
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
	.tuple_to_nfattr	= nf_ct_port_tuple_to_nfattr,
	.nfattr_to_tuple	= nf_ct_port_nfattr_to_tuple,
#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>
	13	#include <linux/netfilter.h>
	14	#include <linux/udp.h>
	15	#include <linux/seq_file.h>
	16	#include <linux/skbuff.h>
	17	#include <linux/ipv6.h>
	18	#include <net/ip6_checksum.h>
	19	#include <net/checksum.h>
	20
	21	#include <linux/netfilter.h>
	22	#include <linux/netfilter_ipv4.h>
	23	#include <linux/netfilter_ipv6.h>
	24	#include <net/netfilter/nf_conntrack_l4proto.h>
	25	#include <net/netfilter/nf_conntrack_ecache.h>
	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
	62	/* Print out the private part of the conntrack. */
	63	static int udplite_print_conntrack(struct seq_file *s,
	64	const struct nf_conn *conntrack)
65	{
66	return 0;
67	}
68
69	/* Returns verdict for packet, and may modify conntracktype */
70	static int udplite_packet(struct nf_conn *conntrack,
71	const struct sk_buff *skb,
72	unsigned int dataoff,
73	enum ip_conntrack_info ctinfo,
74	int pf,
75	unsigned int hooknum)
76	{
77	/* If we've seen traffic both ways, this is some kind of UDP
78	stream. Extend timeout. */
79	if (test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
80	nf_ct_refresh_acct(conntrack, ctinfo, skb,
81	nf_ct_udplite_timeout_stream);
82	/* Also, more likely to be important, and not a probe */
83	if (!test_and_set_bit(IPS_ASSURED_BIT, &conntrack->status))
84	nf_conntrack_event_cache(IPCT_STATUS, skb);
85	} else
86	nf_ct_refresh_acct(conntrack, ctinfo, skb,
87	nf_ct_udplite_timeout);
88
89	return NF_ACCEPT;
90	}
91
92	/* Called when a new connection for this protocol found. */
93	static int udplite_new(struct nf_conn conntrack, const struct sk_buff skb,
94	unsigned int dataoff)
95	{
96	return 1;
97	}
98
99	static int udplite_error(struct sk_buff *skb, unsigned int dataoff,
100	enum ip_conntrack_info *ctinfo,
101	int pf,
102	unsigned int hooknum)
103	{
104	unsigned int udplen = skb->len - dataoff;
105	struct udphdr _hdr, *hdr;
106	unsigned int cscov;
107
108	/* Header is too small? */
109	hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
110	if (hdr == NULL) {
111	if (LOG_INVALID(IPPROTO_UDPLITE))
112	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
113	"nf_ct_udplite: short packet ");
114	return -NF_ACCEPT;
115	}
116
117	cscov = ntohs(hdr->len);
118	if (cscov == 0)
119	cscov = udplen;
120	else if (cscov < sizeof(*hdr) \|\| cscov > udplen) {
121	if (LOG_INVALID(IPPROTO_UDPLITE))
122	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
123	"nf_ct_udplite: invalid checksum coverage ");
124	return -NF_ACCEPT;
125	}
126
127	/* UDPLITE mandates checksums */
128	if (!hdr->check) {
129	if (LOG_INVALID(IPPROTO_UDPLITE))
130	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
131	"nf_ct_udplite: checksum missing ");
132	return -NF_ACCEPT;
133	}
134
135	/* Checksum invalid? Ignore. */
136	if (nf_conntrack_checksum && !skb_csum_unnecessary(skb) &&
137	((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) \|\|
138	(pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING))) {
139	if (pf == PF_INET) {
140	struct iphdr *iph = ip_hdr(skb);
141
142	skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
143	udplen, IPPROTO_UDPLITE, 0);
144	} else {
145	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
146	__wsum hsum = skb_checksum(skb, 0, dataoff, 0);
147
148	skb->csum = ~csum_unfold(
149	csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
150	udplen, IPPROTO_UDPLITE,
151	csum_sub(0, hsum)));
152	}
153
154	skb->ip_summed = CHECKSUM_NONE;
155	if (__skb_checksum_complete_head(skb, dataoff + cscov)) {
156	if (LOG_INVALID(IPPROTO_UDPLITE))
157	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
158	"nf_ct_udplite: bad UDPLite "
159	"checksum ");
160	return -NF_ACCEPT;
161	}
162	skb->ip_summed = CHECKSUM_UNNECESSARY;
163	}
164
165	return NF_ACCEPT;
166	}
167
168	#ifdef CONFIG_SYSCTL
169	static unsigned int udplite_sysctl_table_users;
170	static struct ctl_table_header *udplite_sysctl_header;
171	static struct ctl_table udplite_sysctl_table[] = {
172	{
173	.ctl_name = CTL_UNNUMBERED,
174	.procname = "nf_conntrack_udplite_timeout",
175	.data = &nf_ct_udplite_timeout,
176	.maxlen = sizeof(unsigned int),
177	.mode = 0644,
178	.proc_handler = &proc_dointvec_jiffies,
179	},
180	{
181	.ctl_name = CTL_UNNUMBERED,
182	.procname = "nf_conntrack_udplite_timeout_stream",
183	.data = &nf_ct_udplite_timeout_stream,
184	.maxlen = sizeof(unsigned int),
185	.mode = 0644,
186	.proc_handler = &proc_dointvec_jiffies,
187	},
188	{
189	.ctl_name = 0
190	}
191	};
192	#endif /* CONFIG_SYSCTL */
193
194	static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite4 __read_mostly =
195	{
196	.l3proto = PF_INET,
197	.l4proto = IPPROTO_UDPLITE,
198	.name = "udplite",
199	.pkt_to_tuple = udplite_pkt_to_tuple,
200	.invert_tuple = udplite_invert_tuple,
201	.print_tuple = udplite_print_tuple,
202	.print_conntrack = udplite_print_conntrack,
203	.packet = udplite_packet,
204	.new = udplite_new,
205	.error = udplite_error,
206	#if defined(CONFIG_NF_CT_NETLINK) \|\| defined(CONFIG_NF_CT_NETLINK_MODULE)
207	.tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
208	.nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
209	#endif
210	#ifdef CONFIG_SYSCTL
211	.ctl_table_users = &udplite_sysctl_table_users,
212	.ctl_table_header = &udplite_sysctl_header,
213	.ctl_table = udplite_sysctl_table,
214	#endif
215	};
216
217	static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 __read_mostly =
218	{
219	.l3proto = PF_INET6,
220	.l4proto = IPPROTO_UDPLITE,
221	.name = "udplite",
222	.pkt_to_tuple = udplite_pkt_to_tuple,
223	.invert_tuple = udplite_invert_tuple,
224	.print_tuple = udplite_print_tuple,
225	.print_conntrack = udplite_print_conntrack,
226	.packet = udplite_packet,
227	.new = udplite_new,
228	.error = udplite_error,
229	#if defined(CONFIG_NF_CT_NETLINK) \|\| defined(CONFIG_NF_CT_NETLINK_MODULE)
230	.tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
231	.nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
232	#endif
233	#ifdef CONFIG_SYSCTL
234	.ctl_table_users = &udplite_sysctl_table_users,
235	.ctl_table_header = &udplite_sysctl_header,
236	.ctl_table = udplite_sysctl_table,
237	#endif
238	};
239
240	static int __init nf_conntrack_proto_udplite_init(void)
241	{
242	int err;
243
244	err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite4);
245	if (err < 0)
246	goto err1;
247	err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite6);
248	if (err < 0)
249	goto err2;
250	return 0;
251	err2:
252	nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
253	err1:
254	return err;
255	}
256
257	static void __exit nf_conntrack_proto_udplite_exit(void)
258	{
259	nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite6);
260	nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
261	}
262
263	module_init(nf_conntrack_proto_udplite_init);
264	module_exit(nf_conntrack_proto_udplite_exit);
265
266	MODULE_LICENSE("GPL");