/* 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) == NF_DROP ? -ENOMEM : 0;
}
unsigned int
nf_nat_alloc_null_binding(struct nf_conn *ct, unsigned int hooknum)
{
return __nf_nat_alloc_null_binding(ct, HOOK2MANIP(hooknum));
}
unsigned int
nf_nat_setup_info(struct nf_conn *ct,
const struct nf_nat_range *range,
enum nf_nat_manip_type maniptype)
{
struct nf_conntrack_tuple curr_tuple, new_tuple;
/* Can't setup nat info for confirmed ct. */
if (nf_ct_is_confirmed(ct))
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))
if (!nfct_seqadj_ext_add(ct))
return NF_DROP;
}
if (maniptype == NF_NAT_MANIP_SRC) {
struct nf_nat_conn_key key = {
.net = nf_ct_net(ct),
.tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
.zone = nf_ct_zone(ct),
};
int err;
err = rhltable_insert_key(&nf_nat_bysource_table,
&key,
&ct->nat_bysource,
nf_nat_bysource_params);
if (err)
return NF_DROP;
}
/* 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;
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 int nf_nat_proto_clean(struct nf_conn *ct, void *data)
{
if (nf_nat_proto_remove(ct, data))
return 1;
if ((ct->status & IPS_SRC_NAT_DONE) == 0)
return 0;
/* This netns is being destroyed, and conntrack has nat null binding.
* Remove it from bysource hash, as the table will be freed soon.
*
* Else, when the conntrack is destoyed, nf_nat_cleanup_conntrack()
* will delete entry from already-freed table.
*/
clear_bit(IPS_SRC_NAT_DONE_BIT, &ct->status);
rhltable_remove(&nf_nat_bysource_table, &ct->nat_bysource,
nf_nat_bysource_params);
/* don't delete conntrack. Although that would make things a lot
* simpler, we'd end up flushing all conntracks on nat rmmod.
*/
return 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);
}
