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/* (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 semantic of CHECKSUM_HW is different there
* and moreover root might send raw packets.
* 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);
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