- 根目录:
- net
- netfilter
- nf_nat_core.c
/*
* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
* (C) 2011 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/module.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/skbuff.h>
#include <linux/gfp.h>
#include <net/xfrm.h>
#include <linux/jhash.h>
#include <linux/rtnetlink.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_l3proto.h>
#include <net/netfilter/nf_nat_l4proto.h>
#include <net/netfilter/nf_nat_core.h>
#include <net/netfilter/nf_nat_helper.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_seqadj.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_zones.h>
#include <linux/netfilter/nf_nat.h>
static DEFINE_SPINLOCK(nf_nat_lock);
static DEFINE_MUTEX(nf_nat_proto_mutex);
static const struct nf_nat_l3proto __rcu *nf_nat_l3protos[NFPROTO_NUMPROTO]
__read_mostly;
static const struct nf_nat_l4proto __rcu **nf_nat_l4protos[NFPROTO_NUMPROTO]
__read_mostly;
inline const struct nf_nat_l3proto *
__nf_nat_l3proto_find(u8 family)
{
return rcu_dereference(nf_nat_l3protos[family]);
}
inline const struct nf_nat_l4proto *
__nf_nat_l4proto_find(u8 family, u8 protonum)
{
return rcu_dereference(nf_nat_l4protos[family][protonum]);
}
EXPORT_SYMBOL_GPL(__nf_nat_l4proto_find);
#ifdef CONFIG_XFRM
static void __nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl)
{
const struct nf_nat_l3proto *l3proto;
const struct nf_conn *ct;
enum ip_conntrack_info ctinfo;
enum ip_conntrack_dir dir;
unsigned long statusbit;
u8 family;
ct = nf_ct_get(skb, &ctinfo);
if (ct == NULL)
return;
family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
rcu_read_lock();
l3proto = __nf_nat_l3proto_find(family);
if (l3proto == NULL)
goto out;
dir = CTINFO2DIR(ctinfo);
if (dir == IP_CT_DIR_ORIGINAL)
statusbit = IPS_DST_NAT;
else
statusbit = IPS_SRC_NAT;
l3proto->decode_session(skb, ct, dir, statusbit, fl);
out:
rcu_read_unlock();
}
int nf_xfrm_me_harder(struct sk_buff *skb, unsigned int family)
{
struct flowi fl;
unsigned int hh_len;
struct dst_entry *dst;
int err;
err = xfrm_decode_session(skb, &fl, family);
if (err < 0)
return err;
dst = skb_dst(skb);
if (dst->xfrm)
dst = ((struct xfrm_dst *)dst)->route;
dst_hold(dst);
dst = xfrm_lookup(dev_net(dst->dev), dst, &fl, skb->sk, 0);
if (IS_ERR(dst))
return PTR_ERR(dst);
skb_dst_drop(skb);
skb_dst_set(skb, dst);
/* Change in oif may mean change in hh_len. */
hh_len = skb_dst(skb)->dev->hard_header_len;
if (skb_headroom(skb) < hh_len &&
pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC))
return -ENOMEM;
return 0;
}
EXPORT_SYMBOL(nf_xfrm_me_harder);
#endif /* CONFIG_XFRM */
/* We keep an extra hash for each conntrack, for fast searching. */
static inline unsigned int
hash_by_src(const struct net *net, u16 zone,
const struct nf_conntrack_tuple *tuple)
{
unsigned int hash;
/* Original src, to ensure we map it consistently if poss. */
hash = jhash2((u32 *)&tuple->src, sizeof(tuple->src) / sizeof(u32),
tuple->dst.protonum ^ zone ^ nf_conntrack_hash_rnd);
return ((u64)hash * net->ct.nat_htable_size) >> 32;
}
/* Is this tuple already taken? (not by us) */
int
nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
const struct nf_conn *ignored_conntrack)
{
/* Conntrack tracking doesn't keep track of outgoing tuples; only
* incoming ones. NAT means they don't have a fixed mapping,
* so we invert the tuple and look for the incoming reply.
*
* We could keep a separate hash if this proves too slow.
*/
struct nf_conntrack_tuple reply;
nf_ct_invert_tuplepr(&reply, tuple);
return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
}
EXPORT_SYMBOL(nf_nat_used_tuple);
/* If we source map this tuple so reply looks like reply_tuple, will
* that meet the constraints of range.
*/
static int in_range(const struct nf_nat_l3proto *l3proto,
const struct nf_nat_l4proto *l4proto,
const struct nf_conntrack_tuple *tuple,
const struct nf_nat_range *range)
{
/* If we are supposed to map IPs, then we must be in the
* range specified, otherwise let this drag us onto a new src IP.
*/
if (range->flags & NF_NAT_RANGE_MAP_IPS &&
!l3proto->in_range(tuple, range))
return 0;
if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) ||
l4proto->in_range(tuple, NF_NAT_MANIP_SRC,
&range->min_proto, &range->max_proto))
return 1;
return 0;
}
static inline int
same_src(const struct nf_conn *ct,
const struct nf_conntrack_tuple *tuple)
{
const struct nf_conntrack_tuple *t;
t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
return (t->dst.protonum == tuple->dst.protonum &&
nf_inet_addr_cmp(&t->src.u3, &tuple->src.u3) &&
t->src.u.all == tuple->src.u.all);
}
/* Only called for SRC manip */
static int
find_appropriate_src(struct net *net, u16 zone,
const struct nf_nat_l3proto *l3proto,
const struct nf_nat_l4proto *l4proto,
const struct nf_conntrack_tuple *tuple,
struct nf_conntrack_tuple *result,
const struct nf_nat_range *range)
{
unsigned int h = hash_by_src(net, zone, tuple);
const struct nf_conn_nat *nat;
const struct nf_conn *ct;
hlist_for_each_entry_rcu(nat, &net->ct.nat_bysource[h], bysource) {
ct = nat->ct;
if (same_src(ct, tuple) && nf_ct_zone(ct) == zone) {
/* Copy source part from reply tuple. */
nf_ct_invert_tuplepr(result,
&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
result->dst = tuple->dst;
if (in_range(l3proto, l4proto, result, range))
return 1;
}
}
return 0;
}
/* For [FUTURE] fragmentation handling, we want the least-used
* src-ip/dst-ip/proto triple. Fairness doesn't come into it. Thus
* if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
* 1-65535, we don't do pro-rata allocation based on ports; we choose
* the ip with the lowest src-ip/dst-ip/proto usage.
*/
static void
find_best_ips_proto(u16 zone, struct nf_conntrack_tuple *tuple,
const struct nf_nat_range *range,
const struct nf_conn *ct,
enum nf_nat_manip_type maniptype)
{
union nf_inet_addr *var_ipp;
unsigned int i, max;
/* Host order */
u32 minip, maxip, j, dist;
bool full_range;
/* No IP mapping? Do nothing. */
if (!(range->flags & NF_NAT_RANGE_MAP_IPS))
return;
if (maniptype == NF_NAT_MANIP_SRC)
var_ipp = &tuple->src.u3;
else
var_ipp = &tuple->dst.u3;
/* Fast path: only one choice. */
if (nf_inet_addr_cmp(&range->min_addr, &range->max_addr)) {
*var_ipp = range->min_addr;
return;
}
if (nf_ct_l3num(ct) == NFPROTO_IPV4)
max = sizeof(var_ipp->ip) / sizeof(u32) - 1;
else
max = sizeof(var_ipp->ip6) / sizeof(u32) - 1;
/* Hashing source and destination IPs gives a fairly even
* spread in practice (if there are a small number of IPs
* involved, there usually aren't that many connections
* anyway). The consistency means that servers see the same
* client coming from the same IP (some Internet Banking sites
* like this), even across reboots.
*/
j = jhash2((u32 *)&tuple->src.u3, sizeof(tuple->src.u3) / sizeof(u32),
range->flags & NF_NAT_RANGE_PERSISTENT ?
0 : (__force u32)tuple->dst.u3.all[max] ^ zone);
full_range = false;
for (i = 0; i <= max; i++) {
/* If first bytes of the address are at the maximum, use the
* distance. Otherwise use the full range.
*/
if (!full_range) {
minip = ntohl((__force __be32)range->min_addr.all[i]);
maxip = ntohl((__force __be32)range->max_addr.all[i]);
dist = maxip - minip + 1;
} else {
minip = 0;
dist = ~0;
}
var_ipp->all[i] = (__force __u32)
htonl(minip + (((u64)j * dist) >> 32));
if (var_ipp->all[i] != range->max_addr.all[i])
full_range = true;
if (!(range->flags & NF_NAT_RANGE_PERSISTENT))
j ^= (__force u32)tuple->dst.u3.all[i];
}
}
/* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING,
* we change the source to map into the range. For NF_INET_PRE_ROUTING
* and NF_INET_LOCAL_OUT, we change the destination to map into the
* range. It might not be possible to get a unique tuple, but we try.
* At worst (or if we race), we will end up with a final duplicate in
* __ip_conntrack_confirm and drop the packet. */
static void
get_unique_tuple(struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_tuple *orig_tuple,
const struct nf_nat_range *range,
struct nf_conn *ct,
enum nf_nat_manip_type maniptype)
{
const struct nf_nat_l3proto *l3proto;
const struct nf_nat_l4proto *l4proto;
struct net *net = nf_ct_net(ct);
u16 zone = nf_ct_zone(ct);
rcu_read_lock();
l3proto = __nf_nat_l3proto_find(orig_tuple->src.l3num);
l4proto = __nf_nat_l4proto_find(orig_tuple->src.l3num,
orig_tuple->dst.protonum);
/* 1) If this srcip/proto/src-proto-part is currently mapped,
* and that same mapping gives a unique tuple within the given
* range, use that.
*
* This is only required for source (ie. NAT/masq) mappings.
* So far, we don't do local source mappings, so multiple
* manips not an issue.
*/
if (maniptype == NF_NAT_MANIP_SRC &&
!(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
/* try the original tuple first */
if (in_range(l3proto, l4proto, orig_tuple, range)) {
if (!nf_nat_used_tuple(orig_tuple, ct)) {
*tuple = *orig_tuple;
goto out;
}
} else if (find_appropriate_src(net, zone, l3proto, l4proto,
orig_tuple, tuple, range)) {
pr_debug("get_unique_tuple: Found current src map\n");
if (!nf_nat_used_tuple(tuple, ct))
goto out;
}
}
/* 2) Select the least-used IP/proto combination in the given range */
*tuple = *orig_tuple;
find_best_ips_proto(zone, tuple, range, ct, maniptype);
/* 3) The per-protocol part of the manip is made to map into
* the range to make a unique tuple.
*/
/* Only bother mapping if it's not already in range and unique */
if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
if (l4proto->in_range(tuple, maniptype,
&range->min_proto,
&range->max_proto) &&
(range->min_proto.all == range->max_proto.all ||
!nf_nat_used_tuple(tuple, ct)))
goto out;
} else if (!nf_nat_used_tuple(tuple, ct)) {
goto out;
}
}
/* Last change: get protocol to try to obtain unique tuple. */
l4proto->unique_tuple(l3proto, tuple, range, maniptype, ct);
out:
rcu_read_unlock();
}
unsigned int
nf_nat_setup_info(struct nf_conn *ct,
const struct nf_nat_range *range,
enum nf_nat_manip_type maniptype)
{
struct net *net = nf_ct_net(ct);
struct nf_conntrack_tuple curr_tuple, new_tuple;
struct nf_conn_nat *nat;
/* nat helper or nfctnetlink also setup binding */
nat = nfct_nat(ct);
if (!nat) {
nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
if (nat == NULL) {
pr_debug("failed to add NAT extension\n");
return NF_ACCEPT;
}
}
NF_CT_ASSERT(maniptype == NF_NAT_MANIP_SRC ||
maniptype == NF_NAT_MANIP_DST);
BUG_ON(nf_nat_initialized(ct, maniptype));
/* What we've got will look like inverse of reply. Normally
* this is what is in the conntrack, except for prior
* manipulations (future optimization: if num_manips == 0,
* orig_tp = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple)
*/
nf_ct_invert_tuplepr(&curr_tuple,
&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
struct nf_conntrack_tuple reply;
/* Alter conntrack table so will recognize replies. */
nf_ct_invert_tuplepr(&reply, &new_tuple);
nf_conntrack_alter_reply(ct, &reply);
/* Non-atomic: we own this at the moment. */
if (maniptype == NF_NAT_MANIP_SRC)
ct->status |= IPS_SRC_NAT;
else
ct->status |= IPS_DST_NAT;
if (nfct_help(ct))
nfct_seqadj_ext_add(ct);
}
if (maniptype == NF_NAT_MANIP_SRC) {
unsigned int srchash;
srchash = hash_by_src(net, nf_ct_zone(ct),
&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
spin_lock_bh(&nf_nat_lock);
/* nf_conntrack_alter_reply might re-allocate extension aera */
nat = nfct_nat(ct);
nat->ct = ct;
hlist_add_head_rcu(&nat->bysource,
&net->ct.nat_bysource[srchash]);
spin_unlock_bh(&nf_nat_lock);
}
/* It's done. */
if (maniptype == NF_NAT_MANIP_DST)
ct->status |= IPS_DST_NAT_DONE;
else
ct->status |= IPS_SRC_NAT_DONE;
return NF_ACCEPT;
}
EXPORT_SYMBOL(nf_nat_setup_info);
static unsigned int
__nf_nat_alloc_null_binding(struct nf_conn *ct, enum nf_nat_manip_type manip)
{
/* Force range to this IP; let proto decide mapping for
* per-proto parts (hence not IP_NAT_RANGE_PROTO_SPECIFIED).
* Use reply in case it's already been mangled (eg local packet).
*/
union nf_inet_addr ip =
(manip == NF_NAT_MANIP_SRC ?
ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3 :
ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3);
struct nf_nat_range range = {
.flags = NF_NAT_RANGE_MAP_IPS,
.min_addr = ip,
.max_addr = ip,
};
return nf_nat_setup_info(ct, &range, manip);
}
unsigned int
nf_nat_alloc_null_binding(struct nf_conn *ct, unsigned int hooknum)
{
return __nf_nat_alloc_null_binding(ct, HOOK2MANIP(hooknum));
}
EXPORT_SYMBOL_GPL(nf_nat_alloc_null_binding);
/* Do packet manipulations according to nf_nat_setup_info. */
unsigned int nf_nat_packet(struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int hooknum,
struct sk_buff *skb)
{
const struct nf_nat_l3proto *l3proto;
const struct nf_nat_l4proto *l4proto;
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
unsigned long statusbit;
enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum);
if (mtype == NF_NAT_MANIP_SRC)
statusbit = IPS_SRC_NAT;
else
statusbit = IPS_DST_NAT;
/* Invert if this is reply dir. */
if (dir == IP_CT_DIR_REPLY)
statusbit ^= IPS_NAT_MASK;
/* Non-atomic: these bits don't change. */
if (ct->status & statusbit) {
struct nf_conntrack_tuple target;
/* We are aiming to look like inverse of other direction. */
nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
l3proto = __nf_nat_l3proto_find(target.src.l3num);
l4proto = __nf_nat_l4proto_find(target.src.l3num,
target.dst.protonum);
if (!l3proto->manip_pkt(skb, 0, l4proto, &target, mtype))
return NF_DROP;
}
return NF_ACCEPT;
}
EXPORT_SYMBOL_GPL(nf_nat_packet);
struct nf_nat_proto_clean {
u8 l3proto;
u8 l4proto;
};
/* kill conntracks with affected NAT section */
static int nf_nat_proto_remove(struct nf_conn *i, void *data)
{
const struct nf_nat_proto_clean *clean = data;
struct nf_conn_nat *nat = nfct_nat(i);
if (!nat)
return 0;
if ((clean->l3proto && nf_ct_l3num(i) != clean->l3proto) ||
(clean->l4proto && nf_ct_protonum(i) != clean->l4proto))
return 0;
return i->status & IPS_NAT_MASK ? 1 : 0;
}
static void nf_nat_l4proto_clean(u8 l3proto, u8 l4proto)
{
struct nf_nat_proto_clean clean = {
.l3proto = l3proto,
.l4proto = l4proto,
};
struct net *net;
rtnl_lock();
for_each_net(net)
nf_ct_iterate_cleanup(net, nf_nat_proto_remove, &clean, 0, 0);
rtnl_unlock();
}
static void nf_nat_l3proto_clean(u8 l3proto)
{
struct nf_nat_proto_clean clean = {
.l3proto = l3proto,
};
struct net *net;
rtnl_lock();
for_each_net(net)
nf_ct_iterate_cleanup(net, nf_nat_proto_remove, &clean, 0, 0);
rtnl_unlock();
}
/* Protocol registration. */
int nf_nat_l4proto_register(u8 l3proto, const struct nf_nat_l4proto *l4proto)
{
const struct nf_nat_l4proto **l4protos;
unsigned int i;
int ret = 0;
mutex_lock(&nf_nat_proto_mutex);
if (nf_nat_l4protos[l3proto] == NULL) {
l4protos = kmalloc(IPPROTO_MAX * sizeof(struct nf_nat_l4proto *),
GFP_KERNEL);
if (l4protos == NULL) {
ret = -ENOMEM;
goto out;
}
for (i = 0; i < IPPROTO_MAX; i++)
RCU_INIT_POINTER(l4protos[i], &nf_nat_l4proto_unknown);
/* Before making proto_array visible to lockless readers,
* we must make sure its content is committed to memory.
*/
smp_wmb();
nf_nat_l4protos[l3proto] = l4protos;
}
if (rcu_dereference_protected(
nf_nat_l4protos[l3proto][l4proto->l4proto],
lockdep_is_held(&nf_nat_proto_mutex)
) != &nf_nat_l4proto_unknown) {
ret = -EBUSY;
goto out;
}
RCU_INIT_POINTER(nf_nat_l4protos[l3proto][l4proto->l4proto], l4proto);
out:
mutex_unlock(&nf_nat_proto_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(nf_nat_l4proto_register);
/* No one stores the protocol anywhere; simply delete it. */
void nf_nat_l4proto_unregister(u8 l3proto, const struct nf_nat_l4proto *l4proto)
{
mutex_lock(&nf_nat_proto_mutex);
RCU_INIT_POINTER(nf_nat_l4protos[l3proto][l4proto->l4proto],
&nf_nat_l4proto_unknown);
mutex_unlock(&nf_nat_proto_mutex);
synchronize_rcu();
nf_nat_l4proto_clean(l3proto, l4proto->l4proto);
}
EXPORT_SYMBOL_GPL(nf_nat_l4proto_unregister);
int nf_nat_l3proto_register(const struct nf_nat_l3proto *l3proto)
{
int err;
err = nf_ct_l3proto_try_module_get(l3proto->l3proto);
if (err < 0)
return err;
mutex_lock(&nf_nat_proto_mutex);
RCU_INIT_POINTER(nf_nat_l4protos[l3proto->l3proto][IPPROTO_TCP],
&nf_nat_l4proto_tcp);
RCU_INIT_POINTER(nf_nat_l4protos[l3proto->l3proto][IPPROTO_UDP],
&nf_nat_l4proto_udp);
mutex_unlock(&nf_nat_proto_mutex);
RCU_INIT_POINTER(nf_nat_l3protos[l3proto->l3proto], l3proto);
return 0;
}
EXPORT_SYMBOL_GPL(nf_nat_l3proto_register);
void nf_nat_l3proto_unregister(const struct nf_nat_l3proto *l3proto)
{
mutex_lock(&nf_nat_proto_mutex);
RCU_INIT_POINTER(nf_nat_l3protos[l3proto->l3proto], NULL);
mutex_unlock(&nf_nat_proto_mutex);
synchronize_rcu();
nf_nat_l3proto_clean(l3proto->l3proto);
nf_ct_l3proto_module_put(l3proto->l3proto);
}
EXPORT_SYMBOL_GPL(nf_nat_l3proto_unregister);
/* No one using conntrack by the time this called. */
static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
{
struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT);
if (nat == NULL || nat->ct == NULL)
return;
NF_CT_ASSERT(nat->ct->status & IPS_SRC_NAT_DONE);
spin_lock_bh(&nf_nat_lock);
hlist_del_rcu(&nat->bysource);
spin_unlock_bh(&nf_nat_lock);
}
static void nf_nat_move_storage(void *new, void *old)
{
struct nf_conn_nat *new_nat = new;
struct nf_conn_nat *old_nat = old;
struct nf_conn *ct = old_nat->ct;
if (!ct || !(ct->status & IPS_SRC_NAT_DONE))
return;
spin_lock_bh(&nf_nat_lock);
hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource);
spin_unlock_bh(&nf_nat_lock);
}
static struct nf_ct_ext_type nat_extend __read_mostly = {
.len = sizeof(struct nf_conn_nat),
.align = __alignof__(struct nf_conn_nat),
.destroy = nf_nat_cleanup_conntrack,
.move = nf_nat_move_storage,
.id = NF_CT_EXT_NAT,
.flags = NF_CT_EXT_F_PREALLOC,
};
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_conntrack.h>
static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = {
[CTA_PROTONAT_PORT_MIN] = { .type = NLA_U16 },
[CTA_PROTONAT_PORT_MAX] = { .type = NLA_U16 },
};
static int nfnetlink_parse_nat_proto(struct nlattr *attr,
const struct nf_conn *ct,
struct nf_nat_range *range)
{
struct nlattr *tb[CTA_PROTONAT_MAX+1];
const struct nf_nat_l4proto *l4proto;
int err;
err = nla_parse_nested(tb, CTA_PROTONAT_MAX, attr, protonat_nla_policy);
if (err < 0)
return err;
l4proto = __nf_nat_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
if (l4proto->nlattr_to_range)
err = l4proto->nlattr_to_range(tb, range);
return err;
}
static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
[CTA_NAT_V4_MINIP] = { .type = NLA_U32 },
[CTA_NAT_V4_MAXIP] = { .type = NLA_U32 },
[CTA_NAT_V6_MINIP] = { .len = sizeof(struct in6_addr) },
[CTA_NAT_V6_MAXIP] = { .len = sizeof(struct in6_addr) },
[CTA_NAT_PROTO] = { .type = NLA_NESTED },
};
static int
nfnetlink_parse_nat(const struct nlattr *nat,
const struct nf_conn *ct, struct nf_nat_range *range,
const struct nf_nat_l3proto *l3proto)
{
struct nlattr *tb[CTA_NAT_MAX+1];
int err;
memset(range, 0, sizeof(*range));
err = nla_parse_nested(tb, CTA_NAT_MAX, nat, nat_nla_policy);
if (err < 0)
return err;
err = l3proto->nlattr_to_range(tb, range);
if (err < 0)
return err;
if (!tb[CTA_NAT_PROTO])
return 0;
return nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range);
}
/* This function is called under rcu_read_lock() */
static int
nfnetlink_parse_nat_setup(struct nf_conn *ct,
enum nf_nat_manip_type manip,
const struct nlattr *attr)
{
struct nf_nat_range range;
const struct nf_nat_l3proto *l3proto;
int err;
/* Should not happen, restricted to creating new conntracks
* via ctnetlink.
*/
if (WARN_ON_ONCE(nf_nat_initialized(ct, manip)))
return -EEXIST;
/* Make sure that L3 NAT is there by when we call nf_nat_setup_info to
* attach the null binding, otherwise this may oops.
*/
l3proto = __nf_nat_l3proto_find(nf_ct_l3num(ct));
if (l3proto == NULL)
return -EAGAIN;
/* No NAT information has been passed, allocate the null-binding */
if (attr == NULL)
return __nf_nat_alloc_null_binding(ct, manip);
err = nfnetlink_parse_nat(attr, ct, &range, l3proto);
if (err < 0)
return err;
return nf_nat_setup_info(ct, &range, manip);
}
#else
static int
nfnetlink_parse_nat_setup(struct nf_conn *ct,
enum nf_nat_manip_type manip,
const struct nlattr *attr)
{
return -EOPNOTSUPP;
}
#endif
static int __net_init nf_nat_net_init(struct net *net)
{
/* Leave them the same for the moment. */
net->ct.nat_htable_size = net->ct.htable_size;
net->ct.nat_bysource = nf_ct_alloc_hashtable(&net->ct.nat_htable_size, 0);
if (!net->ct.nat_bysource)
return -ENOMEM;
return 0;
}
static void __net_exit nf_nat_net_exit(struct net *net)
{
struct nf_nat_proto_clean clean = {};
nf_ct_iterate_cleanup(net, &nf_nat_proto_remove, &clean, 0, 0);
synchronize_rcu();
nf_ct_free_hashtable(net->ct.nat_bysource, net->ct.nat_htable_size);
}
static struct pernet_operations nf_nat_net_ops = {
.init = nf_nat_net_init,
.exit = nf_nat_net_exit,
};
static struct nf_ct_helper_expectfn follow_master_nat = {
.name = "nat-follow-master",
.expectfn = nf_nat_follow_master,
};
static int __init nf_nat_init(void)
{
int ret;
ret = nf_ct_extend_register(&nat_extend);
if (ret < 0) {
printk(KERN_ERR "nf_nat_core: Unable to register extension\n");
return ret;
}
ret = register_pernet_subsys(&nf_nat_net_ops);
if (ret < 0)
goto cleanup_extend;
nf_ct_helper_expectfn_register(&follow_master_nat);
/* Initialize fake conntrack so that NAT will skip it */
nf_ct_untracked_status_or(IPS_NAT_DONE_MASK);
BUG_ON(nfnetlink_parse_nat_setup_hook != NULL);
RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook,
nfnetlink_parse_nat_setup);
#ifdef CONFIG_XFRM
BUG_ON(nf_nat_decode_session_hook != NULL);
RCU_INIT_POINTER(nf_nat_decode_session_hook, __nf_nat_decode_session);
#endif
return 0;
cleanup_extend:
nf_ct_extend_unregister(&nat_extend);
return ret;
}
static void __exit nf_nat_cleanup(void)
{
unsigned int i;
unregister_pernet_subsys(&nf_nat_net_ops);
nf_ct_extend_unregister(&nat_extend);
nf_ct_helper_expectfn_unregister(&follow_master_nat);
RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook, NULL);
#ifdef CONFIG_XFRM
RCU_INIT_POINTER(nf_nat_decode_session_hook, NULL);
#endif
for (i = 0; i < NFPROTO_NUMPROTO; i++)
kfree(nf_nat_l4protos[i]);
synchronize_net();
}
MODULE_LICENSE("GPL");
module_init(nf_nat_init);
module_exit(nf_nat_cleanup);