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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.
*/
#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>
#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
static unsigned int udp_timeouts[UDP_CT_MAX] = {
[UDP_CT_UNREPLIED] = 30*HZ,
[UDP_CT_REPLIED] = 180*HZ,
};
static inline struct nf_udp_net *udp_pernet(struct net *net)
{
return &net->ct.nf_ct_proto.udp;
}
static bool 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 false;
tuple->src.u.udp.port = hp->source;
tuple->dst.u.udp.port = hp->dest;
return true;
}
static bool 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 true;
}
/* 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));
}
static unsigned int *udp_get_timeouts(struct net *net)
{
return udp_pernet(net)->timeouts;
}
/* 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,
u_int8_t pf,
unsigned int hooknum,
unsigned int *timeouts)
{
/* 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,
timeouts[UDP_CT_REPLIED]);
/* 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_ASSURED, ct);
} else {
nf_ct_refresh_acct(ct, ctinfo, skb,
timeouts[UDP_CT_UNREPLIED]);
}
return NF_ACCEPT;
}
/* Called when a new connection for this protocol found. */
static bool udp_new(struct nf_conn *ct, const struct sk_buff *skb,
unsigned int dataoff, unsigned int *timeouts)
{
return true;
}
static int udp_error(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
unsigned int dataoff, enum ip_conntrack_info *ctinfo,
u_int8_t 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(net, IPPROTO_UDP))
nf_log_packet(net, 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(net, IPPROTO_UDP))
nf_log_packet(net, 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 (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) {
if (LOG_INVALID(net, IPPROTO_UDP))
nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
"nf_ct_udp: bad UDP checksum ");
return -NF_ACCEPT;
}
return NF_ACCEPT;
}
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_cttimeout.h>
static int udp_timeout_nlattr_to_obj(struct nlattr *tb[],
struct net *net, void *data)
{
unsigned int *timeouts = data;
struct nf_udp_net *un = udp_pernet(net);
/* set default timeouts for UDP. */
timeouts[UDP_CT_UNREPLIED] = un->timeouts[UDP_CT_UNREPLIED];
timeouts[UDP_CT_REPLIED] = un->timeouts[UDP_CT_REPLIED];
if (tb[CTA_TIMEOUT_UDP_UNREPLIED]) {
timeouts[UDP_CT_UNREPLIED] =
ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_UNREPLIED])) * HZ;
}
if (tb[CTA_TIMEOUT_UDP_REPLIED]) {
timeouts[UDP_CT_REPLIED] =
ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_REPLIED])) * HZ;
}
return 0;
}
static int
udp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
{
const unsigned int *timeouts = data;
if (nla_put_be32(skb, CTA_TIMEOUT_UDP_UNREPLIED,
htonl(timeouts[UDP_CT_UNREPLIED] / HZ)) ||
nla_put_be32(skb, CTA_TIMEOUT_UDP_REPLIED,
htonl(timeouts[UDP_CT_REPLIED] / HZ)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -ENOSPC;
}
static const struct nla_policy
udp_timeout_nla_policy[CTA_TIMEOUT_UDP_MAX+1] = {
[CTA_TIMEOUT_UDP_UNREPLIED] = { .type = NLA_U32 },
[CTA_TIMEOUT_UDP_REPLIED] = { .type = NLA_U32 },
};
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
#ifdef CONFIG_SYSCTL
static struct ctl_table udp_sysctl_table[] = {
{
.procname = "nf_conntrack_udp_timeout",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.procname = "nf_conntrack_udp_timeout_stream",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{ }
};
#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
static struct ctl_table udp_compat_sysctl_table[] = {
{
.procname = "ip_conntrack_udp_timeout",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.procname = "ip_conntrack_udp_timeout_stream",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{ }
};
#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
#endif /* CONFIG_SYSCTL */
static int udp_kmemdup_sysctl_table(struct nf_proto_net *pn,
struct nf_udp_net *un)
{
#ifdef CONFIG_SYSCTL
if (pn->ctl_table)
return 0;
pn->ctl_table = kmemdup(udp_sysctl_table,
sizeof(udp_sysctl_table),
GFP_KERNEL);
if (!pn->ctl_table)
return -ENOMEM;
pn->ctl_table[0].data = &un->timeouts[UDP_CT_UNREPLIED];
pn->ctl_table[1].data = &un->timeouts[UDP_CT_REPLIED];
#endif
return 0;
}<
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