[PATCH 051/104] net: bridge: convert MLDv2 Query MRC into msecs_to_jiffies for max_delay

[Luis Henriques]

3.5.7.22 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Daniel Borkmann <dborkman at redhat.com>

commit 2d98c29b6fb3de44d9eaa73c09f9cf7209346383 upstream.

While looking into MLDv1/v2 code, I noticed that bridging code does
not convert it's max delay into jiffies for MLDv2 messages as we do
in core IPv6' multicast code.

RFC3810, 5.1.3. Maximum Response Code says:

  The Maximum Response Code field specifies the maximum time allowed
  before sending a responding Report. The actual time allowed, called
  the Maximum Response Delay, is represented in units of milliseconds,
  and is derived from the Maximum Response Code as follows: [...]

As we update timers that work with jiffies, we need to convert it.

Signed-off-by: Daniel Borkmann <dborkman at redhat.com>
Cc: Linus Lüssing <linus.luessing at web.de>
Cc: Hannes Frederic Sowa <hannes at stressinduktion.org>
Signed-off-by: David S. Miller <davem at davemloft.net>
[ luis: backported to 3.5: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/bridge/br_multicast.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 4c1954b..e881f7f 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1172,7 +1172,8 @@ static int br_ip6_multicast_query(struct net_bridge *br,
 		mld2q = (struct mld2_query *)icmp6_hdr(skb);
 		if (!mld2q->mld2q_nsrcs)
 			group = &mld2q->mld2q_mca;
-		max_delay = mld2q->mld2q_mrc ? MLDV2_MRC(mld2q->mld2q_mrc) : 1;
+
+		max_delay = max(msecs_to_jiffies(MLDV2_MRC(ntohs(mld2q->mld2q_mrc))), 1UL);
 	}
 
 	if (!group)
-- 
1.8.3.2