Subject: [PATCH 07/31] net: ipv6: Do not keep IPv6 addresses when IPv6 is disabled

From: Mike Manning <[email-masked]>
Date: Fri, 12 Aug 2016 12:02:38 +0100

[ Upstream commit bc561632dddd5af0c4444d919f01cbf6d553aa0a ]

If IPv6 is disabled when the option is set to keep IPv6
addresses on link down, userspace is unaware of this as
there is no such indication via netlink. The solution is to
remove the IPv6 addresses in this case, which results in
netlink messages indicating removal of addresses in the
usual manner. This fix also makes the behavior consistent
with the case of having IPv6 disabled first, which stops
IPv6 addresses from being added.

Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional")
Signed-off-by: Mike Manning <[email-masked]>
Acked-by: David Ahern <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/ipv6/addrconf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 047c75a..355b6da 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3469,7 +3469,7 @@ static int addrconf_ifdown(struct net_device *dev, int how)
 	/* combine the user config with event to determine if permanent
 	 * addresses are to be removed from address hash table
 	 */
-	keep_addr = !(how || _keep_addr <= 0);
+	keep_addr = !(how || _keep_addr <= 0 || idev->cnf.disable_ipv6);
 
 	/* Step 2: clear hash table */
 	for (i = 0; i < IN6_ADDR_HSIZE; i++) {
@@ -3525,7 +3525,7 @@ restart:
 	/* re-combine the user config with event to determine if permanent
 	 * addresses are to be removed from the interface list
 	 */
-	keep_addr = (!how && _keep_addr > 0);
+	keep_addr = (!how && _keep_addr > 0 && !idev->cnf.disable_ipv6);
 
 	INIT_LIST_HEAD(&del_list);
 	list_for_each_entry_safe(ifa, tmp, &idev->addr_list, if_list) {
-- 
2.1.0