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/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
*
* 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 net *net,
struct nf_conntrack_tuple *tuple)
{
const struct udphdr *hp;
struct udphdr _hdr;
/* Actually only need first 4 bytes to get ports. */
hp = skb_header_pointer(skb, dataoff, 4, &_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;
}
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 *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;
}
#ifdef CONFIG_NF_CT_PROTO_UDPLITE
static int udplite_error(struct net *net, struct nf_conn *tmpl,
struct sk_buff *skb,
unsigned int dataoff,
u8 pf, unsigned int hooknum)
{
unsigned int udplen = skb->len - dataoff;
const struct udphdr *hdr;
struct udphdr _hdr;
unsigned int cscov;
/* Header is too small? */
hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
if (!hdr) {
if (LOG_INVALID(net, IPPROTO_UDPLITE))
nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
"nf_ct_udplite: short packet ");
return -NF_ACCEPT;
}
cscov = ntohs(hdr->len);
if (cscov == 0) {
cscov = udplen;
} else if (cscov < sizeof(*hdr) || cscov > udplen) {
if (LOG_INVALID(net, IPPROTO_UDPLITE))
nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
"nf_ct_udplite: invalid checksum coverage ");
return -NF_ACCEPT;
}
/* UDPLITE mandates checksums */
if (!hdr->check) {
if (LOG_INVALID(net, IPPROTO_UDPLITE))
nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
"nf_ct_udplite: checksum missing ");
return -NF_ACCEPT;
}
/* Checksum invalid? Ignore. */
if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_UDP,
pf)) {
if (LOG_INVALID(net, IPPROTO_UDPLITE))
nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
"nf_ct_udplite: bad UDPLite checksum ");
return -NF_ACCEPT;
}
return NF_ACCEPT;
}
#endif
static int udp_error(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
unsigned int dataoff,
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,
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