[NETFILTER]: nf_nat: properly use RCU API for nf_nat_protos array
Replace preempt_{enable,disable} based RCU by proper use of the
RCU API and add missing rcu_read_lock/rcu_read_unlock calls in
paths used outside of packet processing context (nfnetlink_conntrack).
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/nf_nat_core.c b/net/ipv4/netfilter/nf_nat_core.c
index cf10108..6d0061f 100644
--- a/net/ipv4/netfilter/nf_nat_core.c
+++ b/net/ipv4/netfilter/nf_nat_core.c
@@ -53,7 +53,7 @@
static inline struct nf_nat_protocol *
__nf_nat_proto_find(u_int8_t protonum)
{
- return nf_nat_protos[protonum];
+ return rcu_dereference(nf_nat_protos[protonum]);
}
struct nf_nat_protocol *
@@ -61,13 +61,11 @@
{
struct nf_nat_protocol *p;
- /* we need to disable preemption to make sure 'p' doesn't get
- * removed until we've grabbed the reference */
- preempt_disable();
+ rcu_read_lock();
p = __nf_nat_proto_find(protonum);
if (!try_module_get(p->me))
p = &nf_nat_unknown_protocol;
- preempt_enable();
+ rcu_read_unlock();
return p;
}
@@ -126,8 +124,8 @@
const struct nf_nat_range *range)
{
struct nf_nat_protocol *proto;
+ int ret = 0;
- proto = __nf_nat_proto_find(tuple->dst.protonum);
/* 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 & IP_NAT_RANGE_MAP_IPS) {
@@ -136,12 +134,15 @@
return 0;
}
+ rcu_read_lock();
+ proto = __nf_nat_proto_find(tuple->dst.protonum);
if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
proto->in_range(tuple, IP_NAT_MANIP_SRC,
&range->min, &range->max))
- return 1;
+ ret = 1;
+ rcu_read_unlock();
- return 0;
+ return ret;
}
static inline int
@@ -268,27 +269,25 @@
/* 3) The per-protocol part of the manip is made to map into
the range to make a unique tuple. */
- proto = nf_nat_proto_find_get(orig_tuple->dst.protonum);
+ rcu_read_lock();
+ proto = __nf_nat_proto_find(orig_tuple->dst.protonum);
/* Change protocol info to have some randomization */
if (range->flags & IP_NAT_RANGE_PROTO_RANDOM) {
proto->unique_tuple(tuple, range, maniptype, ct);
- nf_nat_proto_put(proto);
- return;
+ goto out;
}
/* Only bother mapping if it's not already in range and unique */
if ((!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
proto->in_range(tuple, maniptype, &range->min, &range->max)) &&
- !nf_nat_used_tuple(tuple, ct)) {
- nf_nat_proto_put(proto);
- return;
- }
+ !nf_nat_used_tuple(tuple, ct))
+ goto out;
/* Last change: get protocol to try to obtain unique tuple. */
proto->unique_tuple(tuple, range, maniptype, ct);
-
- nf_nat_proto_put(proto);
+out:
+ rcu_read_unlock();
}
unsigned int
@@ -369,12 +368,11 @@
iph = (void *)(*pskb)->data + iphdroff;
/* Manipulate protcol part. */
- p = nf_nat_proto_find_get(proto);
- if (!p->manip_pkt(pskb, iphdroff, target, maniptype)) {
- nf_nat_proto_put(p);
+
+ /* rcu_read_lock()ed by nf_hook_slow */
+ p = __nf_nat_proto_find(proto);
+ if (!p->manip_pkt(pskb, iphdroff, target, maniptype))
return 0;
- }
- nf_nat_proto_put(p);
iph = (void *)(*pskb)->data + iphdroff;
@@ -529,7 +527,7 @@
ret = -EBUSY;
goto out;
}
- nf_nat_protos[proto->protonum] = proto;
+ rcu_assign_pointer(nf_nat_protos[proto->protonum], proto);
out:
write_unlock_bh(&nf_nat_lock);
return ret;
@@ -540,11 +538,10 @@
void nf_nat_protocol_unregister(struct nf_nat_protocol *proto)
{
write_lock_bh(&nf_nat_lock);
- nf_nat_protos[proto->protonum] = &nf_nat_unknown_protocol;
+ rcu_assign_pointer(nf_nat_protos[proto->protonum],
+ &nf_nat_unknown_protocol);
write_unlock_bh(&nf_nat_lock);
-
- /* Someone could be still looking at the proto in a bh. */
- synchronize_net();
+ synchronize_rcu();
}
EXPORT_SYMBOL(nf_nat_protocol_unregister);
@@ -608,10 +605,10 @@
/* Sew in builtin protocols. */
write_lock_bh(&nf_nat_lock);
for (i = 0; i < MAX_IP_NAT_PROTO; i++)
- nf_nat_protos[i] = &nf_nat_unknown_protocol;
- nf_nat_protos[IPPROTO_TCP] = &nf_nat_protocol_tcp;
- nf_nat_protos[IPPROTO_UDP] = &nf_nat_protocol_udp;
- nf_nat_protos[IPPROTO_ICMP] = &nf_nat_protocol_icmp;
+ rcu_assign_pointer(nf_nat_protos[i], &nf_nat_unknown_protocol);
+ rcu_assign_pointer(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp);
+ rcu_assign_pointer(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp);
+ rcu_assign_pointer(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp);
write_unlock_bh(&nf_nat_lock);
for (i = 0; i < nf_nat_htable_size; i++) {