netfilter: conntrack: avoid reload of ct->status

Compiler can't merge the two test_bit() calls, so load ct->status
once and use non-atomic accesses.

This is fine because IPS_EXPECTED or NAT_CLASH are either set at ct
creation time or not at all, but compiler can't know that.

Signed-off-by: Florian Westphal <fw@strlen.de>

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 81ece11..9e12cad 100644 (file)
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -1854,14 +1854,15 @@ resolve_normal_ct(struct nf_conn *tmpl,
        if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
                ctinfo = IP_CT_ESTABLISHED_REPLY;
        } else {
+               unsigned long status = READ_ONCE(ct->status);
+
                /* Once we've had two way comms, always ESTABLISHED. */
-               if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
+               if (likely(status & IPS_SEEN_REPLY))
                        ctinfo = IP_CT_ESTABLISHED;
-               } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
+               else if (status & IPS_EXPECTED)
                        ctinfo = IP_CT_RELATED;
-               } else {
+               else
                        ctinfo = IP_CT_NEW;
-               }
        }
        nf_ct_set(skb, ct, ctinfo);
        return 0;

diff --git a/net/netfilter/nf_conntrack_proto_udp.c b/net/netfilter/nf_conntrack_proto_udp.c
index 3b516cf..6b92066 100644 (file)
--- a/net/netfilter/nf_conntrack_proto_udp.c
+++ b/net/netfilter/nf_conntrack_proto_udp.c
@@ -88,6 +88,7 @@ int nf_conntrack_udp_packet(struct nf_conn *ct,
                            const struct nf_hook_state *state)
 {
        unsigned int *timeouts;
+       unsigned long status;
 
        if (udp_error(skb, dataoff, state))
                return -NF_ACCEPT;
@@ -96,26 +97,27 @@ int nf_conntrack_udp_packet(struct nf_conn *ct,
        if (!timeouts)
                timeouts = udp_get_timeouts(nf_ct_net(ct));
 
-       if (!nf_ct_is_confirmed(ct))
+       status = READ_ONCE(ct->status);
+       if ((status & IPS_CONFIRMED) == 0)
                ct->proto.udp.stream_ts = 2 * HZ + jiffies;
 
        /* If we've seen traffic both ways, this is some kind of UDP
         * stream. Set Assured.
         */
-       if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
+       if (status & IPS_SEEN_REPLY_BIT) {
                unsigned long extra = timeouts[UDP_CT_UNREPLIED];
                bool stream = false;
 
                /* Still active after two seconds? Extend timeout. */
                if (time_after(jiffies, ct->proto.udp.stream_ts)) {
                        extra = timeouts[UDP_CT_REPLIED];
-                       stream = true;
+                       stream = (status & IPS_ASSURED) == 0;
                }
 
                nf_ct_refresh_acct(ct, ctinfo, skb, extra);
 
                /* never set ASSURED for IPS_NAT_CLASH, they time out soon */
-               if (unlikely((ct->status & IPS_NAT_CLASH)))
+               if (unlikely((status & IPS_NAT_CLASH)))
                        return NF_ACCEPT;
 
                /* Also, more likely to be important, and not a probe */