[deliverable/linux.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,
		     int (*csum)(const struct sk_buff *, unsigned int))
{
	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 semantic of CHECKSUM_HW is different there
	 * and moreover root might send raw packets.
	 * FIXME: Source route IP option packets --RR */
	if (((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) ||
	     (pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING))
	    && skb->ip_summed != CHECKSUM_UNNECESSARY
	    && csum(skb, dataoff)) {
		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;
}

static int csum4(const struct sk_buff *skb, unsigned int dataoff)
{
	return csum_tcpudp_magic(skb->nh.iph->saddr, skb->nh.iph->daddr,
				 skb->len - dataoff, IPPROTO_UDP,
				 skb->ip_summed == CHECKSUM_HW ? skb->csum
				 : skb_checksum(skb, dataoff,
						skb->len - dataoff, 0));
}

static int csum6(const struct sk_buff *skb, unsigned int dataoff)
{
	return csum_ipv6_magic(&skb->nh.ipv6h->saddr, &skb->nh.ipv6h->daddr,
			       skb->len - dataoff, IPPROTO_UDP,
			       skb->ip_summed == CHECKSUM_HW
			       ? csum_sub(skb->csum,
					  skb_checksum(skb, 0, dataoff, 0))
			       : skb_checksum(skb, dataoff, skb->len - dataoff,
					      0));
}

static int udp_error4(struct sk_buff *skb,
		      unsigned int dataoff,
		      enum ip_conntrack_info *ctinfo,
		      int pf,
		      unsigned int hooknum)
{
	return udp_error(skb, dataoff, ctinfo, pf, hooknum, csum4);
}

static int udp_error6(struct sk_buff *skb,
		      unsigned int dataoff,
		      enum ip_conntrack_info *ctinfo,
		      int pf,
		      unsigned int hooknum)
{
	return udp_error(skb, dataoff, ctinfo, pf, hooknum, csum6);
}

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_error4,
#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_error6,
#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,
106	unsigned int hooknum,
107	int (csum)(const struct sk_buff , unsigned int))
108	{
109	unsigned int udplen = skb->len - dataoff;
110	struct udphdr _hdr, *hdr;
111
112	/* Header is too small? */
113	hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
114	if (hdr == NULL) {
115	if (LOG_INVALID(IPPROTO_UDP))
116	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
117	"nf_ct_udp: short packet ");
118	return -NF_ACCEPT;
119	}
120
121	/* Truncated/malformed packets */
122	if (ntohs(hdr->len) > udplen \|\| ntohs(hdr->len) < sizeof(*hdr)) {
123	if (LOG_INVALID(IPPROTO_UDP))
124	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
125	"nf_ct_udp: truncated/malformed packet ");
126	return -NF_ACCEPT;
127	}
128
129	/* Packet with no checksum */
130	if (!hdr->check)
131	return NF_ACCEPT;
132
133	/* Checksum invalid? Ignore.
134	* We skip checking packets on the outgoing path
135	* because the semantic of CHECKSUM_HW is different there
136	* and moreover root might send raw packets.
137	* FIXME: Source route IP option packets --RR */
138	if (((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) \|\|
139	(pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING))
140	&& skb->ip_summed != CHECKSUM_UNNECESSARY
141	&& csum(skb, dataoff)) {
142	if (LOG_INVALID(IPPROTO_UDP))
143	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
144	"nf_ct_udp: bad UDP checksum ");
145	return -NF_ACCEPT;
146	}
147
148	return NF_ACCEPT;
149	}
150
151	static int csum4(const struct sk_buff *skb, unsigned int dataoff)
152	{
153	return csum_tcpudp_magic(skb->nh.iph->saddr, skb->nh.iph->daddr,
154	skb->len - dataoff, IPPROTO_UDP,
155	skb->ip_summed == CHECKSUM_HW ? skb->csum
156	: skb_checksum(skb, dataoff,
157	skb->len - dataoff, 0));
158	}
159
160	static int csum6(const struct sk_buff *skb, unsigned int dataoff)
161	{
162	return csum_ipv6_magic(&skb->nh.ipv6h->saddr, &skb->nh.ipv6h->daddr,
163	skb->len - dataoff, IPPROTO_UDP,
7c6de058 YK	164	skb->ip_summed == CHECKSUM_HW
	165	? csum_sub(skb->csum,
	166	skb_checksum(skb, 0, dataoff, 0))
9fb9cbb1 YK	167	: skb_checksum(skb, dataoff, skb->len - dataoff,
	168	0));
	169	}
	170
	171	static int udp_error4(struct sk_buff *skb,
	172	unsigned int dataoff,
	173	enum ip_conntrack_info *ctinfo,
	174	int pf,
	175	unsigned int hooknum)
	176	{
	177	return udp_error(skb, dataoff, ctinfo, pf, hooknum, csum4);
	178	}
	179
	180	static int udp_error6(struct sk_buff *skb,
	181	unsigned int dataoff,
	182	enum ip_conntrack_info *ctinfo,
	183	int pf,
	184	unsigned int hooknum)
	185	{
	186	return udp_error(skb, dataoff, ctinfo, pf, hooknum, csum6);
	187	}
	188
	189	struct nf_conntrack_protocol nf_conntrack_protocol_udp4 =
	190	{
	191	.l3proto = PF_INET,
	192	.proto = IPPROTO_UDP,
	193	.name = "udp",
	194	.pkt_to_tuple = udp_pkt_to_tuple,
	195	.invert_tuple = udp_invert_tuple,
	196	.print_tuple = udp_print_tuple,
	197	.print_conntrack = udp_print_conntrack,
	198	.packet = udp_packet,
	199	.new = udp_new,
	200	.error = udp_error4,
c1d10adb PNA	201	#if defined(CONFIG_NF_CT_NETLINK) \|\| \
	202	defined(CONFIG_NF_CT_NETLINK_MODULE)
	203	.tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
	204	.nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
	205	#endif
9fb9cbb1 YK	206	};
	207
	208	struct nf_conntrack_protocol nf_conntrack_protocol_udp6 =
	209	{
	210	.l3proto = PF_INET6,
	211	.proto = IPPROTO_UDP,
	212	.name = "udp",
	213	.pkt_to_tuple = udp_pkt_to_tuple,
	214	.invert_tuple = udp_invert_tuple,
	215	.print_tuple = udp_print_tuple,
	216	.print_conntrack = udp_print_conntrack,
	217	.packet = udp_packet,
	218	.new = udp_new,
	219	.error = udp_error6,
c1d10adb PNA	220	#if defined(CONFIG_NF_CT_NETLINK) \|\| \
	221	defined(CONFIG_NF_CT_NETLINK_MODULE)
	222	.tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
	223	.nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
	224	#endif
9fb9cbb1 YK	225	};
	226
	227	EXPORT_SYMBOL(nf_conntrack_protocol_udp4);
	228	EXPORT_SYMBOL(nf_conntrack_protocol_udp6);