netfilter: flowtable: Set offload timeouts according to proto values

Currently the aging period for tcp/udp connections is hard coded to
30 seconds. Aged tcp/udp connections configure a hard coded 120/30
seconds pickup timeout for conntrack.
This configuration may be too aggressive or permissive for some users.

Dynamically configure the nf flow table GC timeout intervals according
to the user defined values.
Signed-off-by: Oz Shlomo <ozsh@nvidia.com>
Reviewed-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_flow_table.h

@@ -177,6 +177,8 @@ struct flow_offload {
 #define NF_FLOW_TIMEOUT (30 * HZ)
 #define nf_flowtable_time_stamp	(u32)jiffies
 
+unsigned long flow_offload_get_timeout(struct flow_offload *flow);
+
 static inline __s32 nf_flow_timeout_delta(unsigned int timeout)
 {
 	return (__s32)(timeout - nf_flowtable_time_stamp);

net/netfilter/nf_flow_table_core.c

@@ -178,12 +178,10 @@ static void flow_offload_fixup_tcp(struct ip_ct_tcp *tcp)
 	tcp->seen[1].td_maxwin = 0;
 }
 
-#define NF_FLOWTABLE_TCP_PICKUP_TIMEOUT	(120 * HZ)
-#define NF_FLOWTABLE_UDP_PICKUP_TIMEOUT	(30 * HZ)
-
 static void flow_offload_fixup_ct_timeout(struct nf_conn *ct)
 {
 	const struct nf_conntrack_l4proto *l4proto;
+	struct net *net = nf_ct_net(ct);
 	int l4num = nf_ct_protonum(ct);
 	unsigned int timeout;
 
@@ -191,12 +189,17 @@ static void flow_offload_fixup_ct_timeout(struct nf_conn *ct)
 	if (!l4proto)
 		return;
 
-	if (l4num == IPPROTO_TCP)
-		timeout = NF_FLOWTABLE_TCP_PICKUP_TIMEOUT;
-	else if (l4num == IPPROTO_UDP)
-		timeout = NF_FLOWTABLE_UDP_PICKUP_TIMEOUT;
-	else
+	if (l4num == IPPROTO_TCP) {
+		struct nf_tcp_net *tn = nf_tcp_pernet(net);
+
+		timeout = tn->offload_pickup;
+	} else if (l4num == IPPROTO_UDP) {
+		struct nf_udp_net *tn = nf_udp_pernet(net);
+
+		timeout = tn->offload_pickup;
+	} else {
 		return;
+	}
 
 	if (nf_flow_timeout_delta(ct->timeout) > (__s32)timeout)
 		ct->timeout = nfct_time_stamp + timeout;
@@ -268,11 +271,35 @@ static const struct rhashtable_params nf_flow_offload_rhash_params = {
 	.automatic_shrinking	= true,
 };
 
+unsigned long flow_offload_get_timeout(struct flow_offload *flow)
+{
+	const struct nf_conntrack_l4proto *l4proto;
+	unsigned long timeout = NF_FLOW_TIMEOUT;
+	struct net *net = nf_ct_net(flow->ct);
+	int l4num = nf_ct_protonum(flow->ct);
+
+	l4proto = nf_ct_l4proto_find(l4num);
+	if (!l4proto)
+		return timeout;
+
+	if (l4num == IPPROTO_TCP) {
+		struct nf_tcp_net *tn = nf_tcp_pernet(net);
+
+		timeout = tn->offload_timeout;
+	} else if (l4num == IPPROTO_UDP) {
+		struct nf_udp_net *tn = nf_udp_pernet(net);
+
+		timeout = tn->offload_timeout;
+	}
+
+	return timeout;
+}
+
 int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow)
 {
 	int err;
 
-	flow->timeout = nf_flowtable_time_stamp + NF_FLOW_TIMEOUT;
+	flow->timeout = nf_flowtable_time_stamp + flow_offload_get_timeout(flow);
 
 	err = rhashtable_insert_fast(&flow_table->rhashtable,
 				     &flow->tuplehash[0].node,
@@ -304,7 +331,7 @@ EXPORT_SYMBOL_GPL(flow_offload_add);
 void flow_offload_refresh(struct nf_flowtable *flow_table,
 			  struct flow_offload *flow)
 {
-	flow->timeout = nf_flowtable_time_stamp + NF_FLOW_TIMEOUT;
+	flow->timeout = nf_flowtable_time_stamp + flow_offload_get_timeout(flow);
 
 	if (likely(!nf_flowtable_hw_offload(flow_table)))
 		return;

net/netfilter/nf_flow_table_offload.c

@@ -937,7 +937,7 @@ static void flow_offload_work_stats(struct flow_offload_work *offload)
 
 	lastused = max_t(u64, stats[0].lastused, stats[1].lastused);
 	offload->flow->timeout = max_t(u64, offload->flow->timeout,
-				       lastused + NF_FLOW_TIMEOUT);
+				       lastused + flow_offload_get_timeout(offload->flow));
 
 	if (offload->flowtable->flags & NF_FLOWTABLE_COUNTER) {
 		if (stats[0].pkts)
@@ -1041,7 +1041,7 @@ void nf_flow_offload_stats(struct nf_flowtable *flowtable,
 	__s32 delta;
 
 	delta = nf_flow_timeout_delta(flow->timeout);
-	if ((delta >= (9 * NF_FLOW_TIMEOUT) / 10))
+	if ((delta >= (9 * flow_offload_get_timeout(flow)) / 10))
 		return;
 
 	offload = nf_flow_offload_work_alloc(flowtable, flow, FLOW_CLS_STATS);