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[NETFILTER]: xt_conntrack match, revision 1
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Introduces the xt_conntrack match revision 1. It uses fixed types, the
new nf_inet_addr and comes with IPv6 support, thereby completely
superseding xt_state.

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Jan Engelhardt authored and David S. Miller committed Jan 28, 2008
1 parent 2e3075a commit 64eb12f
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Showing 2 changed files with 197 additions and 26 deletions.
16 changes: 15 additions & 1 deletion include/linux/netfilter/xt_conntrack.h
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,9 @@
#define _XT_CONNTRACK_H

#include <linux/netfilter/nf_conntrack_tuple_common.h>
#include <linux/in.h>
#ifdef __KERNEL__
# include <linux/in.h>
#endif

#define XT_CONNTRACK_STATE_BIT(ctinfo) (1 << ((ctinfo)%IP_CT_IS_REPLY+1))
#define XT_CONNTRACK_STATE_INVALID (1 << 0)
Expand Down Expand Up @@ -60,4 +62,16 @@ struct xt_conntrack_info
/* Inverse flags */
u_int8_t invflags;
};

struct xt_conntrack_mtinfo1 {
union nf_inet_addr origsrc_addr, origsrc_mask;
union nf_inet_addr origdst_addr, origdst_mask;
union nf_inet_addr replsrc_addr, replsrc_mask;
union nf_inet_addr repldst_addr, repldst_mask;
u_int32_t expires_min, expires_max;
u_int16_t l4proto;
u_int8_t state_mask, status_mask;
u_int8_t match_flags, invert_flags;
};

#endif /*_XT_CONNTRACK_H*/
207 changes: 182 additions & 25 deletions net/netfilter/xt_conntrack.c
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Original file line number Diff line number Diff line change
@@ -1,15 +1,19 @@
/* Kernel module to match connection tracking information.
* Superset of Rusty's minimalistic state match.
/*
* xt_conntrack - Netfilter module to match connection tracking
* information. (Superset of Rusty's minimalistic state match.)
*
* (C) 2001 Marc Boucher (marc@mbsi.ca).
* (C) 2001 Marc Boucher (marc@mbsi.ca).
* Copyright © CC Computer Consultants GmbH, 2007 - 2008
* Jan Engelhardt <jengelh@computergmbh.de>
*
* 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.
* 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/module.h>
#include <linux/skbuff.h>
#include <net/ipv6.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_conntrack.h>
#include <net/netfilter/nf_conntrack.h>
Expand All @@ -18,12 +22,13 @@ MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
MODULE_DESCRIPTION("iptables connection tracking match module");
MODULE_ALIAS("ipt_conntrack");
MODULE_ALIAS("ip6t_conntrack");

static bool
conntrack_mt(const struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, const struct xt_match *match,
const void *matchinfo, int offset, unsigned int protoff,
bool *hotdrop)
conntrack_mt_v0(const struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, const struct xt_match *match,
const void *matchinfo, int offset, unsigned int protoff,
bool *hotdrop)
{
const struct xt_conntrack_info *sinfo = matchinfo;
const struct nf_conn *ct;
Expand Down Expand Up @@ -111,6 +116,134 @@ conntrack_mt(const struct sk_buff *skb, const struct net_device *in,
#undef FWINV
}

static bool
conntrack_addrcmp(const union nf_inet_addr *kaddr,
const union nf_inet_addr *uaddr,
const union nf_inet_addr *umask, unsigned int l3proto)
{
if (l3proto == AF_INET)
return (kaddr->ip & umask->ip) == uaddr->ip;
else if (l3proto == AF_INET6)
return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6,
&uaddr->in6) == 0;
else
return false;
}

static inline bool
conntrack_mt_origsrc(const struct nf_conn *ct,
const struct xt_conntrack_mtinfo1 *info,
unsigned int family)
{
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3,
&info->origsrc_addr, &info->origsrc_mask, family);
}

static inline bool
conntrack_mt_origdst(const struct nf_conn *ct,
const struct xt_conntrack_mtinfo1 *info,
unsigned int family)
{
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3,
&info->origdst_addr, &info->origdst_mask, family);
}

static inline bool
conntrack_mt_replsrc(const struct nf_conn *ct,
const struct xt_conntrack_mtinfo1 *info,
unsigned int family)
{
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3,
&info->replsrc_addr, &info->replsrc_mask, family);
}

static inline bool
conntrack_mt_repldst(const struct nf_conn *ct,
const struct xt_conntrack_mtinfo1 *info,
unsigned int family)
{
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3,
&info->repldst_addr, &info->repldst_mask, family);
}

static bool
conntrack_mt(const struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, const struct xt_match *match,
const void *matchinfo, int offset, unsigned int protoff,
bool *hotdrop)
{
const struct xt_conntrack_mtinfo1 *info = matchinfo;
enum ip_conntrack_info ctinfo;
const struct nf_conn *ct;
unsigned int statebit;

ct = nf_ct_get(skb, &ctinfo);

if (ct == &nf_conntrack_untracked)
statebit = XT_CONNTRACK_STATE_UNTRACKED;
else if (ct != NULL)
statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
else
statebit = XT_CONNTRACK_STATE_INVALID;

if (info->match_flags & XT_CONNTRACK_STATE) {
if (ct != NULL) {
if (test_bit(IPS_SRC_NAT_BIT, &ct->status))
statebit |= XT_CONNTRACK_STATE_SNAT;
if (test_bit(IPS_DST_NAT_BIT, &ct->status))
statebit |= XT_CONNTRACK_STATE_DNAT;
}
if ((info->state_mask & statebit) ^
!(info->invert_flags & XT_CONNTRACK_STATE))
return false;
}

if (ct == NULL)
return info->match_flags & XT_CONNTRACK_STATE;

if ((info->match_flags & XT_CONNTRACK_PROTO) &&
((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum ==
info->l4proto) ^ !(info->invert_flags & XT_CONNTRACK_PROTO)))
return false;

if (info->match_flags & XT_CONNTRACK_ORIGSRC)
if (conntrack_mt_origsrc(ct, info, match->family) ^
!(info->invert_flags & XT_CONNTRACK_ORIGSRC))
return false;

if (info->match_flags & XT_CONNTRACK_ORIGDST)
if (conntrack_mt_origdst(ct, info, match->family) ^
!(info->invert_flags & XT_CONNTRACK_ORIGDST))
return false;

if (info->match_flags & XT_CONNTRACK_REPLSRC)
if (conntrack_mt_replsrc(ct, info, match->family) ^
!(info->invert_flags & XT_CONNTRACK_REPLSRC))
return false;

if (info->match_flags & XT_CONNTRACK_REPLDST)
if (conntrack_mt_repldst(ct, info, match->family) ^
!(info->invert_flags & XT_CONNTRACK_REPLDST))
return false;

if ((info->match_flags & XT_CONNTRACK_STATUS) &&
(!!(info->status_mask & ct->status) ^
!(info->invert_flags & XT_CONNTRACK_STATUS)))
return false;

if (info->match_flags & XT_CONNTRACK_EXPIRES) {
unsigned long expires = 0;

if (timer_pending(&ct->timeout))
expires = (ct->timeout.expires - jiffies) / HZ;
if ((expires >= info->expires_min &&
expires <= info->expires_max) ^
!(info->invert_flags & XT_CONNTRACK_EXPIRES))
return false;
}
return true;
}

static bool
conntrack_mt_check(const char *tablename, const void *ip,
const struct xt_match *match, void *matchinfo,
Expand Down Expand Up @@ -144,7 +277,7 @@ struct compat_xt_conntrack_info
u_int8_t invflags;
};

static void conntrack_mt_compat_from_user(void *dst, void *src)
static void conntrack_mt_compat_from_user_v0(void *dst, void *src)
{
const struct compat_xt_conntrack_info *cm = src;
struct xt_conntrack_info m = {
Expand All @@ -161,7 +294,7 @@ static void conntrack_mt_compat_from_user(void *dst, void *src)
memcpy(dst, &m, sizeof(m));
}

static int conntrack_mt_compat_to_user(void __user *dst, void *src)
static int conntrack_mt_compat_to_user_v0(void __user *dst, void *src)
{
const struct xt_conntrack_info *m = src;
struct compat_xt_conntrack_info cm = {
Expand All @@ -179,29 +312,53 @@ static int conntrack_mt_compat_to_user(void __user *dst, void *src)
}
#endif

static struct xt_match conntrack_mt_reg __read_mostly = {
.name = "conntrack",
.match = conntrack_mt,
.checkentry = conntrack_mt_check,
.destroy = conntrack_mt_destroy,
.matchsize = sizeof(struct xt_conntrack_info),
static struct xt_match conntrack_mt_reg[] __read_mostly = {
{
.name = "conntrack",
.revision = 0,
.family = AF_INET,
.match = conntrack_mt_v0,
.checkentry = conntrack_mt_check,
.destroy = conntrack_mt_destroy,
.matchsize = sizeof(struct xt_conntrack_info),
.me = THIS_MODULE,
#ifdef CONFIG_COMPAT
.compatsize = sizeof(struct compat_xt_conntrack_info),
.compat_from_user = conntrack_mt_compat_from_user,
.compat_to_user = conntrack_mt_compat_to_user,
.compatsize = sizeof(struct compat_xt_conntrack_info),
.compat_from_user = conntrack_mt_compat_from_user_v0,
.compat_to_user = conntrack_mt_compat_to_user_v0,
#endif
.family = AF_INET,
.me = THIS_MODULE,
},
{
.name = "conntrack",
.revision = 1,
.family = AF_INET,
.matchsize = sizeof(struct xt_conntrack_mtinfo1),
.match = conntrack_mt,
.checkentry = conntrack_mt_check,
.destroy = conntrack_mt_destroy,
.me = THIS_MODULE,
},
{
.name = "conntrack",
.revision = 1,
.family = AF_INET6,
.matchsize = sizeof(struct xt_conntrack_mtinfo1),
.match = conntrack_mt,
.checkentry = conntrack_mt_check,
.destroy = conntrack_mt_destroy,
.me = THIS_MODULE,
},
};

static int __init conntrack_mt_init(void)
{
return xt_register_match(&conntrack_mt_reg);
return xt_register_matches(conntrack_mt_reg,
ARRAY_SIZE(conntrack_mt_reg));
}

static void __exit conntrack_mt_exit(void)
{
xt_unregister_match(&conntrack_mt_reg);
xt_unregister_matches(conntrack_mt_reg, ARRAY_SIZE(conntrack_mt_reg));
}

module_init(conntrack_mt_init);
Expand Down

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