[PATCH 3.16 180/328] igmp: fix incorrect unsolicit report count when join group

Ben Hutchings
2018-12-09T22:04:35Z

From: Hangbin Liu <liuhangbin@gmail.com>

commit 4fb7253e4f9a8f06a986a3b317e2f79d9b43d552 upstream.

We should not start timer if im->unsolicit_count equal to 0 after decrease.
Or we will send one more unsolicit report message. i.e. 3 instead of 2 by
default.

Fixes: 1da177e4c3f41 ("Linux-2.6.12-rc2")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/ipv4/igmp.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -795,10 +795,9 @@ static void igmp_timer_expire(unsigned l
spin_lock(&im->lock);
im->tm_running = 0;

- if (im->unsolicit_count) {
- im->unsolicit_count--;
+ if (im->unsolicit_count && --im->unsolicit_count)
igmp_start_timer(im, unsolicited_report_interval(in_dev));
- }
+
im->reporter = 1;
spin_unlock(&im->lock);