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[NETFILTER]: ip_conntrack: properly use RCU API for ip_ct_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
all paths not obviously only used within packet process 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 11:12:40 -08:00 committed by David S. Miller
parent e22a054869
commit 642d628b2c
3 changed files with 26 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
net/ipv4/netfilter/ip_conntrack_core.c
View File

@ -318,9 +318,11 @@ destroy_conntrack(struct nf_conntrack *nfct)
/* To make sure we don't get any weird locking issues here:
* destroy_conntrack() MUST NOT be called with a write lock
* to ip_conntrack_lock!!! -HW */
rcu_read_lock();
proto = __ip_conntrack_proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
if (proto && proto->destroy)
proto->destroy(ct);
rcu_read_unlock();
if (ip_conntrack_destroyed)
ip_conntrack_destroyed(ct);
@ -595,13 +597,13 @@ ip_conntrack_proto_find_get(u_int8_t protocol)
{
struct ip_conntrack_protocol *p;
preempt_disable();
rcu_read_lock();
p = __ip_conntrack_proto_find(protocol);
if (p) {
if (!try_module_get(p->me))
p = &ip_conntrack_generic_protocol;
}
preempt_enable();
rcu_read_unlock();
return p;
}
@ -830,6 +832,7 @@ unsigned int ip_conntrack_in(unsigned int hooknum,
}
#endif
/* rcu_read_lock()ed by nf_hook_slow */
proto = __ip_conntrack_proto_find((*pskb)->nh.iph->protocol);
/* It may be an special packet, error, unclean...
@ -875,8 +878,15 @@ unsigned int ip_conntrack_in(unsigned int hooknum,
int invert_tuplepr(struct ip_conntrack_tuple *inverse,
const struct ip_conntrack_tuple *orig)
{
return ip_ct_invert_tuple(inverse, orig,
__ip_conntrack_proto_find(orig->dst.protonum));
struct ip_conntrack_protocol *proto;
int ret;
rcu_read_lock();
proto = __ip_conntrack_proto_find(orig->dst.protonum);
ret = ip_ct_invert_tuple(inverse, orig, proto);
rcu_read_unlock();
return ret;
}
/* Would two expected things clash? */
@ -1507,11 +1517,11 @@ int __init ip_conntrack_init(void)
/* Don't NEED lock here, but good form anyway. */
write_lock_bh(&ip_conntrack_lock);
for (i = 0; i < MAX_IP_CT_PROTO; i++)
ip_ct_protos[i] = &ip_conntrack_generic_protocol;
rcu_assign_pointer(ip_ct_protos[i], &ip_conntrack_generic_protocol);
/* Sew in builtin protocols. */
ip_ct_protos[IPPROTO_TCP] = &ip_conntrack_protocol_tcp;
ip_ct_protos[IPPROTO_UDP] = &ip_conntrack_protocol_udp;
ip_ct_protos[IPPROTO_ICMP] = &ip_conntrack_protocol_icmp;
rcu_assign_pointer(ip_ct_protos[IPPROTO_TCP], &ip_conntrack_protocol_tcp);
rcu_assign_pointer(ip_ct_protos[IPPROTO_UDP], &ip_conntrack_protocol_udp);
rcu_assign_pointer(ip_ct_protos[IPPROTO_ICMP], &ip_conntrack_protocol_icmp);
write_unlock_bh(&ip_conntrack_lock);
/* For use by ipt_REJECT */

9
net/ipv4/netfilter/ip_conntrack_standalone.c
View File

@ -796,7 +796,7 @@ int ip_conntrack_protocol_register(struct ip_conntrack_protocol *proto)
ret = -EBUSY;
goto out;
}
ip_ct_protos[proto->proto] = proto;
rcu_assign_pointer(ip_ct_protos[proto->proto], proto);
out:
write_unlock_bh(&ip_conntrack_lock);
return ret;
@ -805,11 +805,10 @@ int ip_conntrack_protocol_register(struct ip_conntrack_protocol *proto)
void ip_conntrack_protocol_unregister(struct ip_conntrack_protocol *proto)
{
write_lock_bh(&ip_conntrack_lock);
ip_ct_protos[proto->proto] = &ip_conntrack_generic_protocol;
rcu_assign_pointer(ip_ct_protos[proto->proto],
&ip_conntrack_generic_protocol);
write_unlock_bh(&ip_conntrack_lock);
/* Somebody could be still looking at the proto in bh. */
synchronize_net();
synchronize_rcu();
/* Remove all contrack entries for this protocol */
ip_ct_iterate_cleanup(kill_proto, &proto->proto);

6
net/ipv4/netfilter/ip_nat_core.c
View File

@ -420,6 +420,7 @@ int ip_nat_icmp_reply_translation(struct ip_conntrack *ct,
struct icmphdr icmp;
struct iphdr ip;
} *inside;
struct ip_conntrack_protocol *proto;
struct ip_conntrack_tuple inner, target;
int hdrlen = (*pskb)->nh.iph->ihl * 4;
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
@ -455,10 +456,11 @@ int ip_nat_icmp_reply_translation(struct ip_conntrack *ct,
DEBUGP("icmp_reply_translation: translating error %p manp %u dir %s\n",
*pskb, manip, dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY");
/* rcu_read_lock()ed by nf_hook_slow */
proto = __ip_conntrack_proto_find(inside->ip.protocol);
if (!ip_ct_get_tuple(&inside->ip, *pskb, (*pskb)->nh.iph->ihl*4 +
sizeof(struct icmphdr) + inside->ip.ihl*4,
&inner,
__ip_conntrack_proto_find(inside->ip.protocol)))
&inner, proto))
return 0;
/* Change inner back to look like incoming packet. We do the