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| author | Eric Dumazet <edumazet@google.com> | 2014-11-16 15:23:05 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-11-16 21:59:11 +0100 |
| commit | 960fb622f85180f36d3aff82af53e2be3db2f888 (patch) | |
| tree | c567b80d26270e3d4a3437c9710be6ca0f1eddc3 /net/core | |
| parent | Merge branch 'mv88e6171_temps' (diff) | |
| download | linux-960fb622f85180f36d3aff82af53e2be3db2f888.tar.xz linux-960fb622f85180f36d3aff82af53e2be3db2f888.zip | |
net: provide a per host RSS key generic infrastructure
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: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/ethtool.c | 11 | ||||
| -rw-r--r-- | net/core/sysctl_net_core.c | 19 |
2 files changed, 30 insertions, 0 deletions
diff --git a/net/core/ethtool.c b/net/core/ethtool.c index b0f84f5ddda8..715f51f321e9 100644 --- a/net/core/ethtool.c +++ b/net/core/ethtool.c @@ -25,6 +25,7 @@ #include <linux/slab.h> #include <linux/rtnetlink.h> #include <linux/sched.h> +#include <linux/net.h> /* * Some useful ethtool_ops methods that're device independent. @@ -573,6 +574,16 @@ static int ethtool_copy_validate_indir(u32 *indir, void __user *useraddr, return 0; } +u8 netdev_rss_key[NETDEV_RSS_KEY_LEN]; + +void netdev_rss_key_fill(void *buffer, size_t len) +{ + BUG_ON(len > sizeof(netdev_rss_key)); + net_get_random_once(netdev_rss_key, sizeof(netdev_rss_key)); + memcpy(buffer, netdev_rss_key, len); +} +EXPORT_SYMBOL(netdev_rss_key_fill); + static noinline_for_stack int ethtool_get_rxfh_indir(struct net_device *dev, void __user *useraddr) { diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index f93f092fe226..31baba2a71ce 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -217,6 +217,18 @@ static int set_default_qdisc(struct ctl_table *table, int write, } #endif +static int proc_do_rss_key(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table fake_table; + char buf[NETDEV_RSS_KEY_LEN * 3]; + + snprintf(buf, sizeof(buf), "%*phC", NETDEV_RSS_KEY_LEN, netdev_rss_key); + fake_table.data = buf; + fake_table.maxlen = sizeof(buf); + return proc_dostring(&fake_table, write, buffer, lenp, ppos); +} + static struct ctl_table net_core_table[] = { #ifdef CONFIG_NET { @@ -265,6 +277,13 @@ static struct ctl_table net_core_table[] = { .mode = 0644, .proc_handler = proc_dointvec }, + { + .procname = "netdev_rss_key", + .data = &netdev_rss_key, + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = proc_do_rss_key, + }, #ifdef CONFIG_BPF_JIT { .procname = "bpf_jit_enable", |