[nf-next] netfilter: nf_conntrack, add IPS_HW_OFFLOAD status bit

[Bodong Wang <bodong@xxxxxxxxxxxx>]

This bit indicates that the conntrack entry is offloaded to hardware
flow table. nf_conntrack entry will be tagged with [HW_OFFLOAD] if
it's offload to hardware.

cat /proc/net/nf_conntrack
	ipv4 2 tcp 6 \
	src=1.1.1.17 dst=1.1.1.16 sport=56394 dport=5001 \
	src=1.1.1.16 dst=1.1.1.17 sport=5001 dport=56394 [HW_OFFLOAD] \
	mark=0 zone=0 use=3

Note that HW_OFFLOAD/OFFLOAD/ASSURED are mutually exclusive.

Signed-off-by: Bodong Wang <bodong@xxxxxxxxxxxx>
Reviewed-by: Oz Shlomo <ozsh@xxxxxxxxxxxx>
Reviewed-by: Paul Blakey <paulb@xxxxxxxxxxxx>
---
 include/uapi/linux/netfilter/nf_conntrack_common.h |  8 ++++++--
 net/netfilter/nf_conntrack_standalone.c            |  4 +++-
 net/netfilter/nf_flow_table_offload.c              | 13 +++++++++++++
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/include/uapi/linux/netfilter/nf_conntrack_common.h b/include/uapi/linux/netfilter/nf_conntrack_common.h
index b6f0bb1dc799..4b3395082d15 100644
--- a/include/uapi/linux/netfilter/nf_conntrack_common.h
+++ b/include/uapi/linux/netfilter/nf_conntrack_common.h
@@ -114,15 +114,19 @@ enum ip_conntrack_status {
 	IPS_OFFLOAD_BIT = 14,
 	IPS_OFFLOAD = (1 << IPS_OFFLOAD_BIT),
 
+	/* Conntrack has been offloaded to hardware. */
+	IPS_HW_OFFLOAD_BIT = 15,
+	IPS_HW_OFFLOAD = (1 << IPS_HW_OFFLOAD_BIT),
+
 	/* Be careful here, modifying these bits can make things messy,
 	 * so don't let users modify them directly.
 	 */
 	IPS_UNCHANGEABLE_MASK = (IPS_NAT_DONE_MASK | IPS_NAT_MASK |
 				 IPS_EXPECTED | IPS_CONFIRMED | IPS_DYING |
 				 IPS_SEQ_ADJUST | IPS_TEMPLATE | IPS_UNTRACKED |
-				 IPS_OFFLOAD),
+				 IPS_OFFLOAD | IPS_HW_OFFLOAD),
 
-	__IPS_MAX_BIT = 15,
+	__IPS_MAX_BIT = 16,
 };
 
 /* Connection tracking event types */
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 9b57330c81f8..5a3e6c43ee68 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -348,7 +348,9 @@ static int ct_seq_show(struct seq_file *s, void *v)
 	if (seq_print_acct(s, ct, IP_CT_DIR_REPLY))
 		goto release;
 
-	if (test_bit(IPS_OFFLOAD_BIT, &ct->status))
+	if (test_bit(IPS_HW_OFFLOAD_BIT, &ct->status))
+		seq_puts(s, "[HW_OFFLOAD] ");
+	else if (test_bit(IPS_OFFLOAD_BIT, &ct->status))
 		seq_puts(s, "[OFFLOAD] ");
 	else if (test_bit(IPS_ASSURED_BIT, &ct->status))
 		seq_puts(s, "[ASSURED] ");
diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c
index e3b099c14eff..c9efd20ea65c 100644
--- a/net/netfilter/nf_flow_table_offload.c
+++ b/net/netfilter/nf_flow_table_offload.c
@@ -754,12 +754,15 @@ static void flow_offload_work_add(struct flow_offload_work *offload)
 	err = flow_offload_rule_add(offload, flow_rule);
 	if (err < 0)
 		set_bit(NF_FLOW_HW_REFRESH, &offload->flow->flags);
+	else
+		set_bit(IPS_HW_OFFLOAD_BIT, &offload->flow->ct->status);
 
 	nf_flow_offload_destroy(flow_rule);
 }
 
 static void flow_offload_work_del(struct flow_offload_work *offload)
 {
+	clear_bit(IPS_HW_OFFLOAD_BIT, &offload->flow->ct->status);
 	flow_offload_tuple_del(offload, FLOW_OFFLOAD_DIR_ORIGINAL);
 	flow_offload_tuple_del(offload, FLOW_OFFLOAD_DIR_REPLY);
 	set_bit(NF_FLOW_HW_DEAD, &offload->flow->flags);
@@ -796,6 +799,16 @@ static void flow_offload_work_stats(struct flow_offload_work *offload)
 				       FLOW_OFFLOAD_DIR_REPLY,
 				       stats[1].pkts, stats[1].bytes);
 	}
+
+	/* Clear HW_OFFLOAD immediately when lastused stopped updating, this can
+	 * happen in two scenarios:
+	 *
+	 * 1. TC rule on a higher level device (e.g. vxlan) was offloaded, but
+	 *    HW driver is unloaded.
+	 * 2. One of the shared block driver is unloaded.
+	 */
+	if (!lastused)
+		clear_bit(IPS_HW_OFFLOAD_BIT, &offload->flow->ct->status);
 }
 
 static void flow_offload_work_handler(struct work_struct *work)
-- 
2.21.1