[mirror_ubuntu-bionic-kernel.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.
 */

#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_udp_timeout __read_mostly = 30*HZ;
static unsigned int nf_ct_udp_timeout_stream __read_mostly = 180*HZ;

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

	/* 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));
}

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

	return NF_ACCEPT;
}

/* Called when a new connection for this protocol found. */
static int udp_new(struct nf_conn *ct, 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;
	const struct udphdr *hdr;
	struct udphdr _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 && hooknum == NF_INET_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;
}

#ifdef CONFIG_SYSCTL
static unsigned int udp_sysctl_table_users;
static struct ctl_table_header *udp_sysctl_header;
static struct ctl_table udp_sysctl_table[] = {
	{
		.procname	= "nf_conntrack_udp_timeout",
		.data		= &nf_ct_udp_timeout,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
	},
	{
		.procname	= "nf_conntrack_udp_timeout_stream",
		.data		= &nf_ct_udp_timeout_stream,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
	},
	{
		.ctl_name	= 0
	}
};
#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
static struct ctl_table udp_compat_sysctl_table[] = {
	{
		.procname	= "ip_conntrack_udp_timeout",
		.data		= &nf_ct_udp_timeout,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
	},
	{
		.procname	= "ip_conntrack_udp_timeout_stream",
		.data		= &nf_ct_udp_timeout_stream,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
	},
	{
		.ctl_name	= 0
	}
};
#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
#endif /* CONFIG_SYSCTL */

struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4 __read_mostly =
{
	.l3proto		= PF_INET,
	.l4proto		= IPPROTO_UDP,
	.name			= "udp",
	.pkt_to_tuple		= udp_pkt_to_tuple,
	.invert_tuple		= udp_invert_tuple,
	.print_tuple		= udp_print_tuple,
	.packet			= udp_packet,
	.new			= udp_new,
	.error			= udp_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	= &udp_sysctl_table_users,
	.ctl_table_header	= &udp_sysctl_header,
	.ctl_table		= udp_sysctl_table,
#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
	.ctl_compat_table	= udp_compat_sysctl_table,
#endif
#endif
};
EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp4);

struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6 __read_mostly =
{
	.l3proto		= PF_INET6,
	.l4proto		= IPPROTO_UDP,
	.name			= "udp",
	.pkt_to_tuple		= udp_pkt_to_tuple,
	.invert_tuple		= udp_invert_tuple,
	.print_tuple		= udp_print_tuple,
	.packet			= udp_packet,
	.new			= udp_new,
	.error			= udp_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	= &udp_sysctl_table_users,
	.ctl_table_header	= &udp_sysctl_header,
	.ctl_table		= udp_sysctl_table,
#endif
};
EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_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.
9fb9cbb1 YK	7	*/
	8
	9	#include <linux/types.h>
9fb9cbb1 YK	10	#include <linux/timer.h>
9fb9cbb1 YK	11	#include <linux/module.h>
9fb9cbb1 YK	12	#include <linux/udp.h>
	13	#include <linux/seq_file.h>
	14	#include <linux/skbuff.h>
	15	#include <linux/ipv6.h>
	16	#include <net/ip6_checksum.h>
	17	#include <net/checksum.h>
f6180121	18
9fb9cbb1 YK	19	#include <linux/netfilter.h>
	20	#include <linux/netfilter_ipv4.h>
	21	#include <linux/netfilter_ipv6.h>
605dcad6	22	#include <net/netfilter/nf_conntrack_l4proto.h>
f6180121	23	#include <net/netfilter/nf_conntrack_ecache.h>
f01ffbd6	24	#include <net/netfilter/nf_log.h>
9fb9cbb1	25
933a41e7 PM	26	static unsigned int nf_ct_udp_timeout __read_mostly = 30*HZ;
933a41e7 PM	27	static unsigned int nf_ct_udp_timeout_stream __read_mostly = 180*HZ;
9fb9cbb1 YK	28
	29	static int udp_pkt_to_tuple(const struct sk_buff *skb,
	30	unsigned int dataoff,
	31	struct nf_conntrack_tuple *tuple)
	32	{
da3f13c9 JE	33	const struct udphdr *hp;
da3f13c9 JE	34	struct udphdr _hdr;
9fb9cbb1 YK	35
	36	/* Actually only need first 8 bytes. */
	37	hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
	38	if (hp == NULL)
	39	return 0;
	40
	41	tuple->src.u.udp.port = hp->source;
	42	tuple->dst.u.udp.port = hp->dest;
	43
	44	return 1;
	45	}
	46
	47	static int udp_invert_tuple(struct nf_conntrack_tuple *tuple,
	48	const struct nf_conntrack_tuple *orig)
	49	{
	50	tuple->src.u.udp.port = orig->dst.u.udp.port;
	51	tuple->dst.u.udp.port = orig->src.u.udp.port;
	52	return 1;
	53	}
	54
	55	/* Print out the per-protocol part of the tuple. */
	56	static int udp_print_tuple(struct seq_file *s,
	57	const struct nf_conntrack_tuple *tuple)
	58	{
	59	return seq_printf(s, "sport=%hu dport=%hu ",
	60	ntohs(tuple->src.u.udp.port),
	61	ntohs(tuple->dst.u.udp.port));
	62	}
	63
9fb9cbb1	64	/* Returns verdict for packet, and may modify conntracktype */
c88130bc	65	static int udp_packet(struct nf_conn *ct,
9fb9cbb1 YK	66	const struct sk_buff *skb,
	67	unsigned int dataoff,
	68	enum ip_conntrack_info ctinfo,
	69	int pf,
	70	unsigned int hooknum)
	71	{
	72	/* If we've seen traffic both ways, this is some kind of UDP
	73	stream. Extend timeout. */
c88130bc PM	74	if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
c88130bc PM	75	nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_udp_timeout_stream);
9fb9cbb1	76	/* Also, more likely to be important, and not a probe */
c88130bc	77	if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
9fb9cbb1 YK	78	nf_conntrack_event_cache(IPCT_STATUS, skb);
9fb9cbb1 YK	79	} else
c88130bc	80	nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_udp_timeout);
9fb9cbb1 YK	81
	82	return NF_ACCEPT;
	83	}
	84
	85	/* Called when a new connection for this protocol found. */
c88130bc	86	static int udp_new(struct nf_conn ct, const struct sk_buff skb,
9fb9cbb1 YK	87	unsigned int dataoff)
	88	{
	89	return 1;
	90	}
	91
	92	static int udp_error(struct sk_buff *skb, unsigned int dataoff,
	93	enum ip_conntrack_info *ctinfo,
	94	int pf,
96f6bf82	95	unsigned int hooknum)
9fb9cbb1 YK	96	{
9fb9cbb1 YK	97	unsigned int udplen = skb->len - dataoff;
da3f13c9 JE	98	const struct udphdr *hdr;
da3f13c9 JE	99	struct udphdr _hdr;
9fb9cbb1 YK	100
	101	/* Header is too small? */
	102	hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
	103	if (hdr == NULL) {
	104	if (LOG_INVALID(IPPROTO_UDP))
	105	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
	106	"nf_ct_udp: short packet ");
	107	return -NF_ACCEPT;
	108	}
	109
	110	/* Truncated/malformed packets */
	111	if (ntohs(hdr->len) > udplen \|\| ntohs(hdr->len) < sizeof(*hdr)) {
	112	if (LOG_INVALID(IPPROTO_UDP))
	113	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
	114	"nf_ct_udp: truncated/malformed packet ");
	115	return -NF_ACCEPT;
	116	}
	117
	118	/* Packet with no checksum */
	119	if (!hdr->check)
	120	return NF_ACCEPT;
	121
	122	/* Checksum invalid? Ignore.
	123	* We skip checking packets on the outgoing path
84fa7933	124	* because the checksum is assumed to be correct.
9fb9cbb1	125	* FIXME: Source route IP option packets --RR */
6e23ae2a	126	if (nf_conntrack_checksum && hooknum == NF_INET_PRE_ROUTING &&
96f6bf82	127	nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) {
9fb9cbb1 YK	128	if (LOG_INVALID(IPPROTO_UDP))
	129	nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
	130	"nf_ct_udp: bad UDP checksum ");
	131	return -NF_ACCEPT;
	132	}
	133
	134	return NF_ACCEPT;
	135	}
	136
933a41e7 PM	137	#ifdef CONFIG_SYSCTL
	138	static unsigned int udp_sysctl_table_users;
	139	static struct ctl_table_header *udp_sysctl_header;
	140	static struct ctl_table udp_sysctl_table[] = {
	141	{
933a41e7 PM	142	.procname = "nf_conntrack_udp_timeout",
	143	.data = &nf_ct_udp_timeout,
	144	.maxlen = sizeof(unsigned int),
	145	.mode = 0644,
	146	.proc_handler = &proc_dointvec_jiffies,
	147	},
	148	{
933a41e7 PM	149	.procname = "nf_conntrack_udp_timeout_stream",
	150	.data = &nf_ct_udp_timeout_stream,
	151	.maxlen = sizeof(unsigned int),
	152	.mode = 0644,
	153	.proc_handler = &proc_dointvec_jiffies,
	154	},
	155	{
	156	.ctl_name = 0
	157	}
	158	};
a999e683 PM	159	#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
	160	static struct ctl_table udp_compat_sysctl_table[] = {
	161	{
a999e683 PM	162	.procname = "ip_conntrack_udp_timeout",
	163	.data = &nf_ct_udp_timeout,
	164	.maxlen = sizeof(unsigned int),
	165	.mode = 0644,
	166	.proc_handler = &proc_dointvec_jiffies,
	167	},
	168	{
a999e683 PM	169	.procname = "ip_conntrack_udp_timeout_stream",
	170	.data = &nf_ct_udp_timeout_stream,
	171	.maxlen = sizeof(unsigned int),
	172	.mode = 0644,
	173	.proc_handler = &proc_dointvec_jiffies,
	174	},
	175	{
	176	.ctl_name = 0
	177	}
	178	};
	179	#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
933a41e7 PM	180	#endif /* CONFIG_SYSCTL */
933a41e7 PM	181
61075af5	182	struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4 __read_mostly =
9fb9cbb1 YK	183	{
9fb9cbb1 YK	184	.l3proto = PF_INET,
605dcad6	185	.l4proto = IPPROTO_UDP,
9fb9cbb1 YK	186	.name = "udp",
	187	.pkt_to_tuple = udp_pkt_to_tuple,
	188	.invert_tuple = udp_invert_tuple,
	189	.print_tuple = udp_print_tuple,
9fb9cbb1 YK	190	.packet = udp_packet,
9fb9cbb1 YK	191	.new = udp_new,
96f6bf82	192	.error = udp_error,
e281db5c	193	#if defined(CONFIG_NF_CT_NETLINK) \|\| defined(CONFIG_NF_CT_NETLINK_MODULE)
fdf70832 PM	194	.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
fdf70832 PM	195	.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
f73e924c	196	.nla_policy = nf_ct_port_nla_policy,
c1d10adb	197	#endif
933a41e7 PM	198	#ifdef CONFIG_SYSCTL
	199	.ctl_table_users = &udp_sysctl_table_users,
	200	.ctl_table_header = &udp_sysctl_header,
	201	.ctl_table = udp_sysctl_table,
a999e683 PM	202	#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
	203	.ctl_compat_table = udp_compat_sysctl_table,
	204	#endif
933a41e7	205	#endif
9fb9cbb1	206	};
13b18339	207	EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp4);
9fb9cbb1	208
61075af5	209	struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6 __read_mostly =
9fb9cbb1 YK	210	{
9fb9cbb1 YK	211	.l3proto = PF_INET6,
605dcad6	212	.l4proto = IPPROTO_UDP,
9fb9cbb1 YK	213	.name = "udp",
	214	.pkt_to_tuple = udp_pkt_to_tuple,
	215	.invert_tuple = udp_invert_tuple,
	216	.print_tuple = udp_print_tuple,
9fb9cbb1 YK	217	.packet = udp_packet,
9fb9cbb1 YK	218	.new = udp_new,
96f6bf82	219	.error = udp_error,
e281db5c	220	#if defined(CONFIG_NF_CT_NETLINK) \|\| defined(CONFIG_NF_CT_NETLINK_MODULE)
fdf70832 PM	221	.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
fdf70832 PM	222	.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
f73e924c	223	.nla_policy = nf_ct_port_nla_policy,
c1d10adb	224	#endif
933a41e7 PM	225	#ifdef CONFIG_SYSCTL
	226	.ctl_table_users = &udp_sysctl_table_users,
	227	.ctl_table_header = &udp_sysctl_header,
	228	.ctl_table = udp_sysctl_table,
	229	#endif
9fb9cbb1	230	};
13b18339	231	EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp6);