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

/* (C) 1999-2001 Paul `Rusty' Russell
 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
 *
 * 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.
 *
 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
 *	- enable working with Layer 3 protocol independent connection tracking.
 *
 * Derived from net/ipv4/netfilter/ip_conntrack_proto_udp.c
 */

#include <linux/types.h>
#include <linux/sched.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_protocol.h>

unsigned int nf_ct_udp_timeout = 30*HZ;
unsigned int nf_ct_udp_timeout_stream = 180*HZ;

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

	/* Actually only need first 8 bytes. */
	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 udp_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 udp_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 udp_print_conntrack(struct seq_file *s,
			       const struct nf_conn *conntrack)
{
	return 0;
}

/* Returns verdict for packet, and may modify conntracktype */
static int udp_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_udp_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_udp_timeout);

	return NF_ACCEPT;
}

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

static int udp_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;

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

	/* Truncated/malformed packets */
	if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
		if (LOG_INVALID(IPPROTO_UDP))
			nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
				"nf_ct_udp: truncated/malformed packet ");
		return -NF_ACCEPT;
	}

	/* Packet with no checksum */
	if (!hdr->check)
		return NF_ACCEPT;

	/* Checksum invalid? Ignore.
	 * We skip checking packets on the outgoing path
	 * because the checksum is assumed to be correct.
	 * FIXME: Source route IP option packets --RR */
	if (nf_conntrack_checksum &&
	    ((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) ||
	     (pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING)) &&
	    nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) {
		if (LOG_INVALID(IPPROTO_UDP))
			nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
				"nf_ct_udp: bad UDP checksum ");
		return -NF_ACCEPT;
	}

	return NF_ACCEPT;
}

struct nf_conntrack_protocol nf_conntrack_protocol_udp4 =
{
	.l3proto		= PF_INET,
	.proto			= IPPROTO_UDP,
	.name			= "udp",
	.pkt_to_tuple		= udp_pkt_to_tuple,
	.invert_tuple		= udp_invert_tuple,
	.print_tuple		= udp_print_tuple,
	.print_conntrack	= udp_print_conntrack,
	.packet			= udp_packet,
	.new			= udp_new,
	.error			= udp_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
};

struct nf_conntrack_protocol nf_conntrack_protocol_udp6 =
{
	.l3proto		= PF_INET6,
	.proto			= IPPROTO_UDP,
	.name			= "udp",
	.pkt_to_tuple		= udp_pkt_to_tuple,
	.invert_tuple		= udp_invert_tuple,
	.print_tuple		= udp_print_tuple,
	.print_conntrack	= udp_print_conntrack,
	.packet			= udp_packet,
	.new			= udp_new,
	.error			= udp_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
};

EXPORT_SYMBOL(nf_conntrack_protocol_udp4);
EXPORT_SYMBOL(nf_conntrack_protocol_udp6);
Commit	Line	Data
9fb9cbb1 YK	1	/* (C) 1999-2001 Paul `Rusty' Russell
	2	* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*
	8	* 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
	9	* - enable working with Layer 3 protocol independent connection tracking.
	10	*
	11	* Derived from net/ipv4/netfilter/ip_conntrack_proto_udp.c
	12	*/
	13
	14	#include <linux/types.h>
	15	#include <linux/sched.h>
	16	#include <linux/timer.h>
	17	#include <linux/module.h>
	18	#include <linux/netfilter.h>
	19	#include <linux/udp.h>
	20	#include <linux/seq_file.h>
	21	#include <linux/skbuff.h>
	22	#include <linux/ipv6.h>
	23	#include <net/ip6_checksum.h>
	24	#include <net/checksum.h>
	25	#include <linux/netfilter.h>
	26	#include <linux/netfilter_ipv4.h>
	27	#include <linux/netfilter_ipv6.h>
	28	#include <net/netfilter/nf_conntrack_protocol.h>
	29
babbdb1a PM	30	unsigned int nf_ct_udp_timeout = 30*HZ;
babbdb1a PM	31	unsigned int nf_ct_udp_timeout_stream = 180*HZ;
9fb9cbb1 YK	32
	33	static int udp_pkt_to_tuple(const struct sk_buff *skb,
	34	unsigned int dataoff,
	35	struct nf_conntrack_tuple *tuple)
	36	{
	37	struct udphdr _hdr, *hp;
	38
	39	/* Actually only need first 8 bytes. */
	40	hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
	41	if (hp == NULL)
	42	return 0;
	43
	44	tuple->src.u.udp.port = hp->source;
	45	tuple->dst.u.udp.port = hp->dest;
	46
	47	return 1;
	48	}
	49
	50	static int udp_invert_tuple(struct nf_conntrack_tuple *tuple,
	51	const struct nf_conntrack_tuple *orig)
	52	{
	53	tuple->src.u.udp.port = orig->dst.u.udp.port;
	54	tuple->dst.u.udp.port = orig->src.u.udp.port;
	55	return 1;
	56	}
	57
	58	/* Print out the per-protocol part of the tuple. */
	59	static int udp_print_tuple(struct seq_file *s,
	60	const struct nf_conntrack_tuple *tuple)
	61	{
	62	return seq_printf(s, "sport=%hu dport=%hu ",
	63	ntohs(tuple->src.u.udp.port),
	64	ntohs(tuple->dst.u.udp.port));
	65	}
	66
	67	/* Print out the private part of the conntrack. */
	68	static int udp_print_conntrack(struct seq_file *s,
	69	const struct nf_conn *conntrack)
	70	{
	71	return 0;
	72	}
	73
	74	/* Returns verdict for packet, and may modify conntracktype */
	75	static int udp_packet(struct nf_conn *conntrack,
	76	const struct sk_buff *skb,
	77	unsigned int dataoff,
	78	enum ip_conntrack_info ctinfo,
	79	int pf,
	80	unsigned int hooknum)
	81	{
	82	/* If we've seen traffic both ways, this is some kind of UDP
	83	stream. Extend timeout. */
	84	if (test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
	85	nf_ct_refresh_acct(conntrack, ctinfo, skb,
	86	nf_ct_udp_timeout_stream);
	87	/* Also, more likely to be important, and not a probe */
	88	if (!test_and_set_bit(IPS_ASSURED_BIT, &conntrack->status))
	89	nf_conntrack_event_cache(IPCT_STATUS, skb);
	90	} else
	91	nf_ct_refresh_acct(conntrack, ctinfo, skb, nf_ct_udp_timeout);
	92
	93	return NF_ACCEPT;
	94	}
	95
96	/* Called when a new connection for this protocol found. */
97	static int udp_new(struct nf_conn conntrack, const struct sk_buff skb,
98	unsigned int dataoff)
99	{
100	return 1;
101	}
102
103	static int udp_error(struct sk_buff *skb, unsigned int dataoff,
104	enum ip_conntrack_info *ctinfo,
105	int pf,
96f6bf82	106	unsigned int hooknum)
9fb9cbb1 YK	107	{
	108	unsigned int udplen = skb->len - dataoff;
	109	struct udphdr _hdr, *hdr;
	110
	111	/* Header is too small? */
	112	hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
	113	if (hdr == NULL) {
	114	if (LOG_INVALID(IPPROTO_UDP))
	115	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
	116	"nf_ct_udp: short packet ");
	117	return -NF_ACCEPT;
	118	}
	119
	120	/* Truncated/malformed packets */
	121	if (ntohs(hdr->len) > udplen \|\| ntohs(hdr->len) < sizeof(*hdr)) {
	122	if (LOG_INVALID(IPPROTO_UDP))
	123	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
	124	"nf_ct_udp: truncated/malformed packet ");
	125	return -NF_ACCEPT;
	126	}
	127
	128	/* Packet with no checksum */
	129	if (!hdr->check)
	130	return NF_ACCEPT;
	131
	132	/* Checksum invalid? Ignore.
	133	* We skip checking packets on the outgoing path
84fa7933	134	* because the checksum is assumed to be correct.
9fb9cbb1	135	* FIXME: Source route IP option packets --RR */
39a27a35 PM	136	if (nf_conntrack_checksum &&
39a27a35 PM	137	((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) \|\|
96f6bf82 PM	138	(pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING)) &&
96f6bf82 PM	139	nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) {
9fb9cbb1 YK	140	if (LOG_INVALID(IPPROTO_UDP))
	141	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
	142	"nf_ct_udp: bad UDP checksum ");
	143	return -NF_ACCEPT;
	144	}
	145
	146	return NF_ACCEPT;
	147	}
	148
9fb9cbb1 YK	149	struct nf_conntrack_protocol nf_conntrack_protocol_udp4 =
	150	{
	151	.l3proto = PF_INET,
	152	.proto = IPPROTO_UDP,
	153	.name = "udp",
	154	.pkt_to_tuple = udp_pkt_to_tuple,
	155	.invert_tuple = udp_invert_tuple,
	156	.print_tuple = udp_print_tuple,
	157	.print_conntrack = udp_print_conntrack,
	158	.packet = udp_packet,
	159	.new = udp_new,
96f6bf82	160	.error = udp_error,
c1d10adb PNA	161	#if defined(CONFIG_NF_CT_NETLINK) \|\| \
	162	defined(CONFIG_NF_CT_NETLINK_MODULE)
	163	.tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
	164	.nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
	165	#endif
9fb9cbb1 YK	166	};
	167
	168	struct nf_conntrack_protocol nf_conntrack_protocol_udp6 =
	169	{
	170	.l3proto = PF_INET6,
	171	.proto = IPPROTO_UDP,
	172	.name = "udp",
	173	.pkt_to_tuple = udp_pkt_to_tuple,
	174	.invert_tuple = udp_invert_tuple,
	175	.print_tuple = udp_print_tuple,
	176	.print_conntrack = udp_print_conntrack,
	177	.packet = udp_packet,
	178	.new = udp_new,
96f6bf82	179	.error = udp_error,
c1d10adb PNA	180	#if defined(CONFIG_NF_CT_NETLINK) \|\| \
	181	defined(CONFIG_NF_CT_NETLINK_MODULE)
	182	.tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
	183	.nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
	184	#endif
9fb9cbb1 YK	185	};
	186
	187	EXPORT_SYMBOL(nf_conntrack_protocol_udp4);
	188	EXPORT_SYMBOL(nf_conntrack_protocol_udp6);