[PATCH] ipv6 addrconf: disallow rtr_solicits < -1

["Maciej Żenczykowski" <zenczykowski@gmail.com>]

From: Maciej Żenczykowski <maze@google.com>

This disallows setting /proc/sys/net/ipv6/conf/*/router_solicitations
to values below -1.

-1 continues to mean an unlimited number of retransmits.

Note: this depends on 'ipv6 addrconf: remove addrconf_sysctl_hop_limit()'

Signed-off-by: Maciej Żenczykowski <maze@google.com>
---
 net/ipv6/addrconf.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index cbd9343751a2..511b76e6a50e 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -5729,6 +5729,7 @@ int addrconf_sysctl_ignore_routes_with_linkdown(struct ctl_table *ctl,
 	return ret;
 }
 
+static const int minus_one = -1;
 static const int one = 1;
 static const int two_five_five = 255;
 
@@ -5789,7 +5790,8 @@ static const struct ctl_table addrconf_sysctl[] = {
 		.data		= &ipv6_devconf.rtr_solicits,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= (void *)&minus_one,
 	},
 	{
 		.procname	= "router_solicitation_interval",
-- 
2.8.0.rc3.226.g39d4020