blob: e1f409aa0006dc31273064f6eea0f5058ab85d03 [file] [log] [blame]
/* (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_conntrack_timeout.h>
#include <net/netfilter/nf_log.h>
#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
static const unsigned int udp_timeouts[UDP_CT_MAX] = {
[UDP_CT_UNREPLIED] = 30*HZ,
[UDP_CT_REPLIED] = 120*HZ,
};
static unsigned int *udp_get_timeouts(struct net *net)
{
return nf_udp_pernet(net)->timeouts;
}
static void udp_error_log(const struct sk_buff *skb,
const struct nf_hook_state *state,
const char *msg)
{
nf_l4proto_log_invalid(skb, state->net, state->pf,
IPPROTO_UDP, "%s", msg);
}
static bool udp_error(struct sk_buff *skb,
unsigned int dataoff,
const struct nf_hook_state *state)
{
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) {
udp_error_log(skb, state, "short packet");
return true;
}
/* Truncated/malformed packets */
if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
udp_error_log(skb, state, "truncated/malformed packet");
return true;
}
/* Packet with no checksum */
if (!hdr->check)
return false;
/* 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 (state->hook == NF_INET_PRE_ROUTING &&
state->net->ct.sysctl_checksum &&
nf_checksum(skb, state->hook, dataoff, IPPROTO_UDP, state->pf)) {
udp_error_log(skb, state, "bad checksum");
return true;
}
return false;
}
/* Returns verdict for packet, and may modify conntracktype */
int nf_conntrack_udp_packet(struct nf_conn *ct,
struct sk_buff *skb,
unsigned int dataoff,
enum ip_conntrack_info ctinfo,
const struct nf_hook_state *state)
{
unsigned int *timeouts;
if (udp_error(skb, dataoff, state))
return -NF_ACCEPT;
timeouts = nf_ct_timeout_lookup(ct);
if (!timeouts)
timeouts = udp_get_timeouts(nf_ct_net(ct));
if (!nf_ct_is_confirmed(ct))
ct->proto.udp.stream_ts = 2 * HZ + jiffies;
/* If we've seen traffic both ways, this is some kind of UDP
* stream. Set Assured.
*/
if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
unsigned long extra = timeouts[UDP_CT_UNREPLIED];
/* Still active after two seconds? Extend timeout. */
if (time_after(jiffies, ct->proto.udp.stream_ts))
extra = timeouts[UDP_CT_REPLIED];
nf_ct_refresh_acct(ct, ctinfo, skb, extra);
/* 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;
}
#ifdef CONFIG_NF_CT_PROTO_UDPLITE
static void udplite_error_log(const struct sk_buff *skb,
const struct nf_hook_state *state,
const char *msg)
{
nf_l4proto_log_invalid(skb, state->net, state->pf,
IPPROTO_UDPLITE, "%s", msg);
}
static bool udplite_error(struct sk_buff *skb,
unsigned int dataoff,
const struct nf_hook_state *state)
{
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) {
udplite_error_log(skb, state, "short packet");
return true;
}
cscov = ntohs(hdr->len);
if (cscov == 0) {
cscov = udplen;
} else if (cscov < sizeof(*hdr) || cscov > udplen) {
udplite_error_log(skb, state, "invalid checksum coverage");
return true;
}
/* UDPLITE mandates checksums */
if (!hdr->check) {
udplite_error_log(skb, state, "checksum missing");
return true;
}
/* Checksum invalid? Ignore. */
if (state->hook == NF_INET_PRE_ROUTING &&
state->net->ct.sysctl_checksum &&
nf_checksum_partial(skb, state->hook, dataoff, cscov, IPPROTO_UDP,
state->pf)) {
udplite_error_log(skb, state, "bad checksum");
return true;
}
return false;
}
/* Returns verdict for packet, and may modify conntracktype */
int nf_conntrack_udplite_packet(struct nf_conn *ct,
struct sk_buff *skb,
unsigned int dataoff,
enum ip_conntrack_info ctinfo,
const struct nf_hook_state *state)
{
unsigned int *timeouts;
if (udplite_error(skb, dataoff, state))
return -NF_ACCEPT;
timeouts = nf_ct_timeout_lookup(ct);
if (!timeouts)
timeouts = udp_get_timeouts(nf_ct_net(ct));
/* 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;
}
#endif
#ifdef CONFIG_NF_CONNTRACK_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 = nf_udp_pernet(net);
if (!timeouts)
timeouts = un->timeouts;
/* 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_CONNTRACK_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,
},
{ }
};
#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;
}
static int udp_init_net(struct net *net)
{
struct nf_udp_net *un = nf_udp_pernet(net);
struct nf_proto_net *pn = &un->pn;
if (!pn->users) {
int i;
for (i = 0; i < UDP_CT_MAX; i++)
un->timeouts[i] = udp_timeouts[i];
}
return udp_kmemdup_sysctl_table(pn, un);
}
static struct nf_proto_net *udp_get_net_proto(struct net *net)
{
return &net->ct.nf_ct_proto.udp.pn;
}
const struct nf_conntrack_l4proto nf_conntrack_l4proto_udp =
{
.l4proto = IPPROTO_UDP,
.allow_clash = true,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
.nla_policy = nf_ct_port_nla_policy,
#endif
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
.ctnl_timeout = {
.nlattr_to_obj = udp_timeout_nlattr_to_obj,
.obj_to_nlattr = udp_timeout_obj_to_nlattr,
.nlattr_max = CTA_TIMEOUT_UDP_MAX,
.obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX,
.nla_policy = udp_timeout_nla_policy,
},
#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
.init_net = udp_init_net,
.get_net_proto = udp_get_net_proto,
};
#ifdef CONFIG_NF_CT_PROTO_UDPLITE
const struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite =
{
.l4proto = IPPROTO_UDPLITE,
.allow_clash = true,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
.nla_policy = nf_ct_port_nla_policy,
#endif
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
.ctnl_timeout = {
.nlattr_to_obj = udp_timeout_nlattr_to_obj,
.obj_to_nlattr = udp_timeout_obj_to_nlattr,
.nlattr_max = CTA_TIMEOUT_UDP_MAX,
.obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX,
.nla_policy = udp_timeout_nla_policy,
},
#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
.init_net = udp_init_net,
.get_net_proto = udp_get_net_proto,
};
#endif