• Nikolay Aleksandrov's avatar
    bridge: multicast: restore perm router ports on multicast enable · 5f0c00de
    Nikolay Aleksandrov authored
    BugLink: http://bugs.launchpad.net/bugs/1642573
    
    [ Upstream commit 7cb3f921 ]
    
    Satish reported a problem with the perm multicast router ports not getting
    reenabled after some series of events, in particular if it happens that the
    multicast snooping has been disabled and the port goes to disabled state
    then it will be deleted from the router port list, but if it moves into
    non-disabled state it will not be re-added because the mcast snooping is
    still disabled, and enabling snooping later does nothing.
    
    Here are the steps to reproduce, setup br0 with snooping enabled and eth1
    added as a perm router (multicast_router = 2):
    1. $ echo 0 > /sys/class/net/br0/bridge/multicast_snooping
    2. $ ip l set eth1 down
    ^ This step deletes the interface from the router list
    3. $ ip l set eth1 up
    ^ This step does not add it again because mcast snooping is disabled
    4. $ echo 1 > /sys/class/net/br0/bridge/multicast_snooping
    5. $ bridge -d -s mdb show
    <empty>
    
    At this point we have mcast enabled and eth1 as a perm router (value = 2)
    but it is not in the router list which is incorrect.
    
    After this change:
    1. $ echo 0 > /sys/class/net/br0/bridge/multicast_snooping
    2. $ ip l set eth1 down
    ^ This step deletes the interface from the router list
    3. $ ip l set eth1 up
    ^ This step does not add it again because mcast snooping is disabled
    4. $ echo 1 > /sys/class/net/br0/bridge/multicast_snooping
    5. $ bridge -d -s mdb show
    router ports on br0: eth1
    
    Note: we can directly do br_multicast_enable_port for all because the
    querier timer already has checks for the port state and will simply
    expire if it's in blocking/disabled. See the comment added by
    commit 9aa66382 ("bridge: multicast: add a comment to
    br_port_state_selection about blocking state")
    
    Fixes: 561f1103 ("bridge: Add multicast_snooping sysfs toggle")
    Reported-by: default avatarSatish Ashok <sashok@cumulusnetworks.com>
    Signed-off-by: default avatarNikolay Aleksandrov <nikolay@cumulusnetworks.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
    5f0c00de
br_multicast.c 49.2 KB