[PATCH] net: let flow have same hash in two directions

From: zhang kai
Date: Wed Jul 28 2021 - 06:55:30 EST


using same source and destination ip/port for flow hash calculation
within the two directions.

Signed-off-by: zhang kai <zhangkaiheb@xxxxxxx>
---
net/core/flow_dissector.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 3ed7c98a9..dfc18f212 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -1504,7 +1504,7 @@ __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)
@@ -1515,11 +1515,11 @@ 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;
@@ -1527,13 +1527,13 @@ 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;
--
2.17.1