From 8d228758f90f234d1c5c6696960a5bd6a392c751 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Linus=20L=C3=BCssing?= Date: Tue, 23 May 2017 21:53:52 -0400 Subject: [PATCH] ipv6: Fix IPv6 packet loss in scenarios involving roaming + snooping switches MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit [ Upstream commit a088d1d73a4bcfd7bc482f8d08375b9b665dc3e5 ] When for instance a mobile Linux device roams from one access point to another with both APs sharing the same broadcast domain and a multicast snooping switch in between: 1) (c) <~~~> (AP1) <--[SSW]--> (AP2) 2) (AP1) <--[SSW]--> (AP2) <~~~> (c) Then currently IPv6 multicast packets will get lost for (c) until an MLD Querier sends its next query message. The packet loss occurs because upon roaming the Linux host so far stayed silent regarding MLD and the snooping switch will therefore be unaware of the multicast topology change for a while. This patch fixes this by always resending MLD reports when an interface change happens, for instance from NO-CARRIER to CARRIER state. Signed-off-by: Linus Lüssing Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/ipv6/addrconf.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 7090fef372cc..8cf3fc7c2932 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -3211,9 +3211,15 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event, } if (idev) { - if (idev->if_flags & IF_READY) - /* device is already configured. */ + if (idev->if_flags & IF_READY) { + /* device is already configured - + * but resend MLD reports, we might + * have roamed and need to update + * multicast snooping switches + */ + ipv6_mc_up(idev); break; + } idev->if_flags |= IF_READY; } -- 2.34.1