• Eric Dumazet's avatar
    net: provide a per host RSS key generic infrastructure · 960fb622
    Eric Dumazet authored
    RSS (Receive Side Scaling) typically uses Toeplitz hash and a 40 or 52 bytes
    RSS key.
    
    Some drivers use a constant (and well known key), some drivers use a random
    key per port, making bonding setups hard to tune. Well known keys increase
    attack surface, considering that number of queues is usually a power of two.
    
    This patch provides infrastructure to help drivers doing the right thing.
    
    netdev_rss_key_fill() should be used by drivers to initialize their RSS key,
    even if they provide ethtool -X support to let user redefine the key later.
    
    A new /proc/sys/net/core/netdev_rss_key file can be used to get the host
    RSS key even for drivers not providing ethtool -x support, in case some
    applications want to precisely setup flows to match some RX queues.
    
    Tested:
    
    myhost:~# cat /proc/sys/net/core/netdev_rss_key
    11:63:99:bb:79:fb:a5:a7:07:45:b2:20:bf:02:42:2d:08:1a:dd:19:2b:6b:23:ac:56:28:9d:70:c3:ac:e8:16:4b:b7:c1:10:53:a4:78:41:36:40:74:b6:15:ca:27:44:aa:b3:4d:72
    
    myhost:~# ethtool -x eth0
    RX flow hash indirection table for eth0 with 8 RX ring(s):
        0:      0     1     2     3     4     5     6     7
    RSS hash key:
    11:63:99:bb:79:fb:a5:a7:07:45:b2:20:bf:02:42:2d:08:1a:dd:19:2b:6b:23:ac:56:28:9d:70:c3:ac:e8:16:4b:b7:c1:10:53:a4:78:41
    Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    960fb622
sysctl_net_core.c 9.88 KB