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DEFINITIONS
This source file includes following definitions.
- conntrack_mt_v0
- conntrack_addrcmp
- conntrack_mt_origsrc
- conntrack_mt_origdst
- conntrack_mt_replsrc
- conntrack_mt_repldst
- ct_proto_port_check
- conntrack_mt
- conntrack_mt_check
- conntrack_mt_destroy
- conntrack_mt_compat_from_user_v0
- conntrack_mt_compat_to_user_v0
- conntrack_mt_init
- conntrack_mt_exit
/*
* xt_conntrack - Netfilter module to match connection tracking
* information. (Superset of Rusty's minimalistic state match.)
*
* (C) 2001 Marc Boucher (marc@mbsi.ca).
* Copyright © CC Computer Consultants GmbH, 2007 - 2008
*
* 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>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
MODULE_DESCRIPTION("Xtables: connection tracking state match");
MODULE_ALIAS("ipt_conntrack");
MODULE_ALIAS("ip6t_conntrack");
static bool
conntrack_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
{
const struct xt_conntrack_info *sinfo = par->matchinfo;
const struct nf_conn *ct;
enum ip_conntrack_info ctinfo;
unsigned int statebit;
ct = nf_ct_get(skb, &ctinfo);
#define FWINV(bool, invflg) ((bool) ^ !!(sinfo->invflags & (invflg)))
if (ct == &nf_conntrack_untracked)
statebit = XT_CONNTRACK_STATE_UNTRACKED;
else if (ct)
statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
else
statebit = XT_CONNTRACK_STATE_INVALID;
if (sinfo->flags & XT_CONNTRACK_STATE) {
if (ct) {
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 (FWINV((statebit & sinfo->statemask) == 0,
XT_CONNTRACK_STATE))
return false;
}
if (ct == NULL) {
if (sinfo->flags & ~XT_CONNTRACK_STATE)
return false;
return true;
}
if (sinfo->flags & XT_CONNTRACK_PROTO &&
FWINV(nf_ct_protonum(ct) !=
sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum,
XT_CONNTRACK_PROTO))
return false;
if (sinfo->flags & XT_CONNTRACK_ORIGSRC &&
FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip &
sinfo->sipmsk[IP_CT_DIR_ORIGINAL].s_addr) !=
sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip,
XT_CONNTRACK_ORIGSRC))
return false;
if (sinfo->flags & XT_CONNTRACK_ORIGDST &&
FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.ip &
sinfo->dipmsk[IP_CT_DIR_ORIGINAL].s_addr) !=
sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip,
XT_CONNTRACK_ORIGDST))
return false;
if (sinfo->flags & XT_CONNTRACK_REPLSRC &&
FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip &
sinfo->sipmsk[IP_CT_DIR_REPLY].s_addr) !=
sinfo->tuple[IP_CT_DIR_REPLY].src.ip,
XT_CONNTRACK_REPLSRC))
return false;
if (sinfo->flags & XT_CONNTRACK_REPLDST &&
FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip &
sinfo->dipmsk[IP_CT_DIR_REPLY].s_addr) !=
sinfo->tuple[IP_CT_DIR_REPLY].dst.ip,
XT_CONNTRACK_REPLDST))
return false;
if (sinfo->flags & XT_CONNTRACK_STATUS &&
FWINV((ct->status & sinfo->statusmask) == 0,
XT_CONNTRACK_STATUS))
return false;
if(sinfo->flags & XT_CONNTRACK_EXPIRES) {
unsigned long expires = timer_pending(&ct->timeout) ?
(ct->timeout.expires - jiffies)/HZ : 0;
if (FWINV(!(expires >= sinfo->expires_min &&
expires <= sinfo->expires_max),
XT_CONNTRACK_EXPIRES))
return false;
}
return true;
#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 == NFPROTO_IPV4)
return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0;
else if (l3proto == NFPROTO_IPV6)
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,
u_int8_t 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,
u_int8_t 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,
u_int8_t 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,
u_int8_t family)
{
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3,
&info->repldst_addr, &info->repldst_mask, family);
}
static inline bool
ct_proto_port_check(const struct xt_conntrack_mtinfo1 *info,
const struct nf_conn *ct)
{
const struct nf_conntrack_tuple *tuple;
tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
if ((info->match_flags & XT_CONNTRACK_PROTO) &&
(nf_ct_protonum(ct) == info->l4proto) ^
!(info->invert_flags & XT_CONNTRACK_PROTO))
return false;
/* Shortcut to match all recognized protocols by using ->src.all. */
if ((info->match_flags & XT_CONNTRACK_ORIGSRC_PORT) &&
(tuple->src.u.all == info->origsrc_port) ^
!(info->invert_flags & XT_CONNTRACK_ORIGSRC_PORT))
return false;
if ((info->match_flags & XT_CONNTRACK_ORIGDST_PORT) &&
(tuple->dst.u.all == info->origdst_port) ^
!(info->invert_flags & XT_CONNTRACK_ORIGDST_PORT))
return false;
tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
if ((info->match_flags & XT_CONNTRACK_REPLSRC_PORT) &&
(tuple->src.u.all == info->replsrc_port) ^
!(info->invert_flags & XT_CONNTRACK_REPLSRC_PORT))
return false;
if ((info->match_flags & XT_CONNTRACK_REPLDST_PORT) &&
(tuple->dst.u.all == info->repldst_port) ^
!(info->invert_flags & XT_CONNTRACK_REPLDST_PORT))
return false;
return true;
}
static bool
conntrack_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
const struct xt_conntrack_mtinfo1 *info = par->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_DIRECTION) &&
(CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) ^
!!(info->invert_flags & XT_CONNTRACK_DIRECTION))
return false;
if (info->match_flags & XT_CONNTRACK_ORIGSRC)
if (conntrack_mt_origsrc(ct, info, par->family) ^
!(info->invert_flags & XT_CONNTRACK_ORIGSRC))
return false;
if (info->match_flags & XT_CONNTRACK_ORIGDST)
if (conntrack_mt_origdst(ct, info, par->family) ^
!(info->invert_flags & XT_CONNTRACK_ORIGDST))
return false;
if (info->match_flags & XT_CONNTRACK_REPLSRC)
if (conntrack_mt_replsrc(ct, info, par->family) ^
!(info->invert_flags & XT_CONNTRACK_REPLSRC))
return false;
if (info->match_flags & XT_CONNTRACK_REPLDST)
if (conntrack_mt_repldst(ct, info, par->family) ^
!(info->invert_flags & XT_CONNTRACK_REPLDST))
return false;
if (!ct_proto_port_check(info, ct))
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 struct xt_mtchk_param *par)
{
if (nf_ct_l3proto_try_module_get(par->family) < 0) {
printk(KERN_WARNING "can't load conntrack support for "
"proto=%u\n", par->family);
return false;
}
return true;
}
static void conntrack_mt_destroy(const struct xt_mtdtor_param *par)
{
nf_ct_l3proto_module_put(par->family);
}
#ifdef CONFIG_COMPAT
struct compat_xt_conntrack_info
{
compat_uint_t statemask;
compat_uint_t statusmask;
struct ip_conntrack_old_tuple tuple[IP_CT_DIR_MAX];
struct in_addr sipmsk[IP_CT_DIR_MAX];
struct in_addr dipmsk[IP_CT_DIR_MAX];
compat_ulong_t expires_min;
compat_ulong_t expires_max;
u_int8_t flags;
u_int8_t invflags;
};
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 = {
.statemask = cm->statemask,
.statusmask = cm->statusmask,
.expires_min = cm->expires_min,
.expires_max = cm->expires_max,
.flags = cm->flags,
.invflags = cm->invflags,
};
memcpy(m.tuple, cm->tuple, sizeof(m.tuple));
memcpy(m.sipmsk, cm->sipmsk, sizeof(m.sipmsk));
memcpy(m.dipmsk, cm->dipmsk, sizeof(m.dipmsk));
memcpy(dst, &m, sizeof(m));
}
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 = {
.statemask = m->statemask,
.statusmask = m->statusmask,
.expires_min = m->expires_min,
.expires_max = m->expires_max,
.flags = m->flags,
.invflags = m->invflags,
};
memcpy(cm.tuple, m->tuple, sizeof(cm.tuple));
memcpy(cm.sipmsk, m->sipmsk, sizeof(cm.sipmsk));
memcpy(cm.dipmsk, m->dipmsk, sizeof(cm.dipmsk));
return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
}
#endif
static struct xt_match conntrack_mt_reg[] __read_mostly = {
{
.name = "conntrack",
.revision = 0,
.family = NFPROTO_IPV4,
.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_v0,
.compat_to_user = conntrack_mt_compat_to_user_v0,
#endif
},
{
.name = "conntrack",
.revision = 1,
.family = NFPROTO_UNSPEC,
.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_matches(conntrack_mt_reg,
ARRAY_SIZE(conntrack_mt_reg));
}
static void __exit conntrack_mt_exit(void)
{
xt_unregister_matches(conntrack_mt_reg, ARRAY_SIZE(conntrack_mt_reg));
}
module_init(conntrack_mt_init);
module_exit(conntrack_mt_exit);