[patch net-next 1/6] ipv4: Send a netevent whenever multipath hash policy is changed

[Jiri Pirko]

From: Ido Schimmel <ido...@mellanox.com>

Devices performing IPv4 forwarding need to update their multipath hash
policy whenever it is changed.

Inform these devices by generating a netevent.

Signed-off-by: Ido Schimmel <ido...@mellanox.com>
Reviewed-by: Petr Machata <pe...@mellanox.com>
Signed-off-by: Jiri Pirko <j...@mellanox.com>
---
 include/net/netevent.h     |  1 +
 net/ipv4/sysctl_net_ipv4.c | 20 +++++++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/include/net/netevent.h b/include/net/netevent.h
index f440df1..e3f0e8f 100644
--- a/include/net/netevent.h
+++ b/include/net/netevent.h
@@ -25,6 +25,7 @@ enum netevent_notif_type {
        NETEVENT_NEIGH_UPDATE = 1, /* arg is struct neighbour ptr */
        NETEVENT_REDIRECT,         /* arg is struct netevent_redirect ptr */
        NETEVENT_DELAY_PROBE_TIME_UPDATE, /* arg is struct neigh_parms ptr */
+       NETEVENT_MULTIPATH_HASH_UPDATE, /* arg is struct net ptr */
 };
 
 int register_netevent_notifier(struct notifier_block *nb);
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 4602af6..8dcc2b1 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -25,6 +25,7 @@
 #include <net/inet_frag.h>
 #include <net/ping.h>
 #include <net/protocol.h>
+#include <net/netevent.h>
 
 static int zero;
 static int one = 1;
@@ -385,6 +386,23 @@ static int proc_tcp_available_ulp(struct ctl_table *ctl,
        return ret;
 }
 
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+static int proc_fib_multipath_hash_policy(struct ctl_table *table, int write,
+                                         void __user *buffer, size_t *lenp,
+                                         loff_t *ppos)
+{
+       struct net *net = container_of(table->data, struct net,
+           ipv4.sysctl_fib_multipath_hash_policy);
+       int ret;
+
+       ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+       if (write && ret == 0)
+               call_netevent_notifiers(NETEVENT_MULTIPATH_HASH_UPDATE, net);
+
+       return ret;
+}
+#endif
+
 static struct ctl_table ipv4_table[] = {
        {
                .procname       = "tcp_max_orphans",
@@ -907,7 +925,7 @@ static struct ctl_table ipv4_net_table[] = {
                .data           = 
&init_net.ipv4.sysctl_fib_multipath_hash_policy,
                .maxlen         = sizeof(int),
                .mode           = 0644,
-               .proc_handler   = proc_dointvec_minmax,
+               .proc_handler   = proc_fib_multipath_hash_policy,
                .extra1         = &zero,
                .extra2         = &one,
        },
-- 
2.9.5