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[NETFILTER]: nf_nat: properly use RCU API for nf_nat_protos array

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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>
This commit is contained in:
Patrick McHardy 2007-02-12 11:12:26 -08:00 committed by David S. Miller
parent a441dfdbb2
commit e22a054869
1 changed files with 28 additions and 31 deletions
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59
net/ipv4/netfilter/nf_nat_core.c
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@ -53,7 +53,7 @@ static struct nf_nat_protocol *nf_nat_protos[MAX_IP_NAT_PROTO];
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 @@ nf_nat_proto_find_get(u_int8_t protonum)
{
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 @@ in_range(const struct nf_conntrack_tuple *tuple,
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 @@ in_range(const struct nf_conntrack_tuple *tuple,
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 @@ get_unique_tuple(struct nf_conntrack_tuple *tuple,
/* 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 @@ manip_pkt(u_int16_t proto,
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 @@ int nf_nat_protocol_register(struct nf_nat_protocol *proto)
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 @@ EXPORT_SYMBOL(nf_nat_protocol_register);
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 @@ static int __init nf_nat_init(void)
/* 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++) {