net: let flow have same hash in two directions

stable inclusion
from stable-v5.10.146
commit e90001e1dd96cb98e53c6dab6d657df09d919e96
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6D0VX

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e90001e1dd96cb98e53c6dab6d657df09d919e96

--------------------------------

[ Upstream commit 1e60cebf ]

using same source and destination ip/port for flow hash calculation
within the two directions.
Signed-off-by: Nzhang kai <zhangkaiheb@126.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Stable-dep-of: 64ae13ed ("net: core: fix flow symmetric hash")
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
Reviewed-by: NZheng Zengkai <zhengzengkai@huawei.com>

net/core/flow_dissector.c

@@ -1484,7 +1484,7 @@ __be32 flow_get_u32_dst(const struct flow_keys *flow)
 }
 EXPORT_SYMBOL(flow_get_u32_dst);
 
-/* Sort the source and destination IP (and the ports if the IP are the same),
+/* Sort the source and destination IP and the ports,
  * to have consistent hash within the two directions
  */
 static inline void __flow_hash_consistentify(struct flow_keys *keys)
@@ -1495,11 +1495,11 @@ static inline void __flow_hash_consistentify(struct flow_keys *keys)
 	case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 		addr_diff = (__force u32)keys->addrs.v4addrs.dst -
 			    (__force u32)keys->addrs.v4addrs.src;
-		if ((addr_diff < 0) ||
-		    (addr_diff == 0 &&
-		     ((__force u16)keys->ports.dst <
-		      (__force u16)keys->ports.src))) {
+		if (addr_diff < 0)
 			swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst);
+
+		if ((__force u16)keys->ports.dst <
+		    (__force u16)keys->ports.src) {
 			swap(keys->ports.src, keys->ports.dst);
 		}
 		break;
@@ -1507,13 +1507,13 @@ static inline void __flow_hash_consistentify(struct flow_keys *keys)
 		addr_diff = memcmp(&keys->addrs.v6addrs.dst,
 				   &keys->addrs.v6addrs.src,
 				   sizeof(keys->addrs.v6addrs.dst));
-		if ((addr_diff < 0) ||
-		    (addr_diff == 0 &&
-		     ((__force u16)keys->ports.dst <
-		      (__force u16)keys->ports.src))) {
+		if (addr_diff < 0) {
 			for (i = 0; i < 4; i++)
 				swap(keys->addrs.v6addrs.src.s6_addr32[i],
 				     keys->addrs.v6addrs.dst.s6_addr32[i]);
+		}
+		if ((__force u16)keys->ports.dst <
+		    (__force u16)keys->ports.src) {
 			swap(keys->ports.src, keys->ports.dst);
 		}
 		break;