[NETFILTER]: Use only 32bit counters for CONNTRACK_ACCT

Initially we used 64bit counters for conntrack-based accounting, since we
had no event mechanism to tell userspace that our counters are about to
overflow. With nfnetlink_conntrack, we now have such a event mechanism and
thus can save 16bytes per connection.

Signed-off-by: Harald Welte <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/netfilter/nfnetlink_conntrack.h

···
 
 enum ctattr_counters {
 	CTA_COUNTERS_UNSPEC,
-	CTA_COUNTERS_PACKETS,
-	CTA_COUNTERS_BYTES,
+	CTA_COUNTERS_PACKETS,		/* old 64bit counters */
+	CTA_COUNTERS_BYTES,		/* old 64bit counters */
+	CTA_COUNTERS32_PACKETS,
+	CTA_COUNTERS32_BYTES,
 	__CTA_COUNTERS_MAX
 };
 #define CTA_COUNTERS_MAX (__CTA_COUNTERS_MAX - 1)

include/linux/netfilter_ipv4/ip_conntrack.h

···
 	/* NAT info */
 	IPCT_NATINFO_BIT = 10,
 	IPCT_NATINFO = (1 << IPCT_NATINFO_BIT),
+
+	/* Counter highest bit has been set */
+	IPCT_COUNTER_FILLING_BIT = 11,
+	IPCT_COUNTER_FILLING = (1 << IPCT_COUNTER_FILLING_BIT),
 };
 
 enum ip_conntrack_expect_events {
···
 
 struct ip_conntrack_counter
 {
-	u_int64_t packets;
-	u_int64_t bytes;
+	u_int32_t packets;
+	u_int32_t bytes;
 };
 
 struct ip_conntrack_helper;

net/ipv4/netfilter/ip_conntrack_core.c

···
 			unsigned long extra_jiffies,
 			int do_acct)
 {
-	int do_event = 0;
+	int event = 0;
 
 	IP_NF_ASSERT(ct->timeout.data == (unsigned long)ct);
 	IP_NF_ASSERT(skb);
···
 	/* If not in hash table, timer will not be active yet */
 	if (!is_confirmed(ct)) {
 		ct->timeout.expires = extra_jiffies;
-		do_event = 1;
+		event = IPCT_REFRESH;
 	} else {
 		/* Need del_timer for race avoidance (may already be dying). */
 		if (del_timer(&ct->timeout)) {
 			ct->timeout.expires = jiffies + extra_jiffies;
 			add_timer(&ct->timeout);
-			do_event = 1;
+			event = IPCT_REFRESH;
 		}
 	}
 
···
 		ct->counters[CTINFO2DIR(ctinfo)].packets++;
 		ct->counters[CTINFO2DIR(ctinfo)].bytes += 
 						ntohs(skb->nh.iph->tot_len);
+		if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
+		    || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
+			event |= IPCT_COUNTER_FILLING;
 	}
 #endif
 
 	write_unlock_bh(&ip_conntrack_lock);
 
 	/* must be unlocked when calling event cache */
-	if (do_event)
-		ip_conntrack_event_cache(IPCT_REFRESH, skb);
+	if (event)
+		ip_conntrack_event_cache(event, skb);
 }
 
 #if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \

net/ipv4/netfilter/ip_conntrack_netlink.c

···
 	struct nfattr *nest_count = NFA_NEST(skb, type);
 	u_int64_t tmp;
 
-	tmp = cpu_to_be64(ct->counters[dir].packets);
-	NFA_PUT(skb, CTA_COUNTERS_PACKETS, sizeof(u_int64_t), &tmp);
+	tmp = htonl(ct->counters[dir].packets);
+	NFA_PUT(skb, CTA_COUNTERS32_PACKETS, sizeof(u_int32_t), &tmp);
 
-	tmp = cpu_to_be64(ct->counters[dir].bytes);
-	NFA_PUT(skb, CTA_COUNTERS_BYTES, sizeof(u_int64_t), &tmp);
+	tmp = htonl(ct->counters[dir].bytes);
+	NFA_PUT(skb, CTA_COUNTERS32_BYTES, sizeof(u_int32_t), &tmp);
 
 	NFA_NEST_END(skb, nest_count);