From 974dc36a87274d7bae13e7dddd3364fecf5b3e7c Mon Sep 17 00:00:00 2001 From: Helmut Schaa Date: Wed, 8 Jan 2014 13:48:49 +0100 Subject: [PATCH] netdev-linux: Let interface flag survive internal port setup Due to a race condition when bringing up an internal port on Linux some interface flags (e.g. IFF_MULTICAST) are falsely reset. This happens because netlink events may be processed after the according netdev has been brought up (which sets interface flags). Fix this by reading the interface flags just before updating them if they have not been updated by from the kernel yet. Signed-off-by: Helmut Schaa --- lib/netdev-linux.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/lib/netdev-linux.c +++ b/lib/netdev-linux.c @@ -3485,7 +3485,13 @@ update_flags(struct netdev_linux *netdev unsigned int old_flags, new_flags; int error = 0; - old_flags = netdev->ifi_flags; + if (!(netdev->cache_valid & VALID_DRVINFO)) { + /* Most likely the debvice flags are not in sync yet, fetch them now */ + get_flags(&netdev->up, &old_flags); + } else { + old_flags = netdev->ifi_flags; + } + *old_flagsp = iff_to_nd_flags(old_flags); new_flags = (old_flags & ~nd_to_iff_flags(off)) | nd_to_iff_flags(on); if (new_flags != old_flags) {