From: suresh kumar suresh2514@gmail.com
[ Upstream commit 49aefd131739df552f83c566d0665744c30b1d70 ]
Commit b5f862180d70 was introduced to discard lowest hash bit for layer3+4 hashing but it also removes last bit from non layer3+4 hashing
Below script shows layer2+3 hashing will result in same slave to be used with above commit. $ cat hash.py #/usr/bin/python3.6
h_dests=[0xa0, 0xa1] h_source=0xe3 hproto=0x8 saddr=0x1e7aa8c0 daddr=0x17aa8c0
for h_dest in h_dests: hash = (h_dest ^ h_source ^ hproto ^ saddr ^ daddr) hash ^= hash >> 16 hash ^= hash >> 8 print(hash)
print("with last bit removed") for h_dest in h_dests: hash = (h_dest ^ h_source ^ hproto ^ saddr ^ daddr) hash ^= hash >> 16 hash ^= hash >> 8 hash = hash >> 1 print(hash)
Output: $ python3.6 hash.py 522133332 522133333 <-------------- will result in both slaves being used
with last bit removed 261066666 261066666 <-------------- only single slave used
Signed-off-by: suresh kumar suresh2514@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/bonding/bond_main.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 46c3301a5e07..2e75b7e8f70b 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -3817,14 +3817,19 @@ static bool bond_flow_dissect(struct bonding *bond, struct sk_buff *skb, const v return true; }
-static u32 bond_ip_hash(u32 hash, struct flow_keys *flow) +static u32 bond_ip_hash(u32 hash, struct flow_keys *flow, int xmit_policy) { hash ^= (__force u32)flow_get_u32_dst(flow) ^ (__force u32)flow_get_u32_src(flow); hash ^= (hash >> 16); hash ^= (hash >> 8); + /* discard lowest hash bit to deal with the common even ports pattern */ - return hash >> 1; + if (xmit_policy == BOND_XMIT_POLICY_LAYER34 || + xmit_policy == BOND_XMIT_POLICY_ENCAP34) + return hash >> 1; + + return hash; }
/* Generate hash based on xmit policy. If @skb is given it is used to linearize @@ -3854,7 +3859,7 @@ static u32 __bond_xmit_hash(struct bonding *bond, struct sk_buff *skb, const voi memcpy(&hash, &flow.ports.ports, sizeof(hash)); }
- return bond_ip_hash(hash, &flow); + return bond_ip_hash(hash, &flow, bond->params.xmit_policy); }
/** @@ -5012,7 +5017,7 @@ static u32 bond_sk_hash_l34(struct sock *sk) /* L4 */ memcpy(&hash, &flow.ports.ports, sizeof(hash)); /* L3 */ - return bond_ip_hash(hash, &flow); + return bond_ip_hash(hash, &flow, BOND_XMIT_POLICY_LAYER34); }
static struct net_device *__bond_sk_get_lower_dev(struct bonding *bond,