ipv6: set all.accept_dad to 0 by default

NicolasDichtel · davem330 · commit 094009531612 · 2017-11-15T13:56:45.000+09:00
With commits 35e015e and a2d3f3e, the global 'accept_dad' flag is also taken into account (default value is 1). If either global or per-interface flag is non-zero, DAD will be enabled on a given interface. This is not backward compatible: before those patches, the user could disable DAD just by setting the per-interface flag to 0. Now, the user instead needs to set both flags to 0 to actually disable DAD. Restore the previous behaviour by setting the default for the global 'accept_dad' flag to 0. This way, DAD is still enabled by default, as per-interface flags are set to 1 on device creation, but setting them to 0 is enough to disable DAD on a given interface. - Before 35e015e1f57a7 and a2d3f3e: global per-interface DAD enabled [default] 1 1 yes X 0 no X 1 yes - After 35e015e and a2d3f3e: global per-interface DAD enabled [default] 1 1 yes 0 0 no 0 1 yes 1 0 yes - After this fix: global per-interface DAD enabled 1 1 yes 0 0 no [default] 0 1 yes 1 0 yes Fixes: 35e015e ("ipv6: fix net.ipv6.conf.all interface DAD handlers") Fixes: a2d3f3e ("ipv6: fix net.ipv6.conf.all.accept_dad behaviour for real") CC: Stefano Brivio <sbrivio@redhat.com> CC: Matteo Croce <mcroce@redhat.com> CC: Erik Kline <ek@google.com> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Acked-by: Stefano Brivio <sbrivio@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
@@ -231,7 +231,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
 	.proxy_ndp		= 0,
 	.accept_source_route	= 0,	/* we do not accept RH0 by default. */
 	.disable_ipv6		= 0,
-	.accept_dad		= 1,
+	.accept_dad		= 0,
 	.suppress_frag_ndisc	= 1,
 	.accept_ra_mtu		= 1,
 	.stable_secret		= {
