This patchset introduces new state variables to combine and reduce the
number of checks we would otherwise perform on every multicast packet
in fast/data path.
The second reason for introducing these new, internal multicast active
variables is to later propagate a safety mechanism which was introduced
in b00589af3b04 ("bridge: disable snooping if there is no querier") to
switchdev/DSA, too. That is to notify switchdev/DSA if multicast
snooping can safely be applied without potential packet loss.
Regards, Linus
---
# Changelog
Changelog to / follow-up of: [PATCH net-next 0/5] net: bridge: propagate safe
mcast snooping to switchdev + DSA
-> https://lkml.org/lkml/2025/5/22/1413
* removed the switchdev/DSA changes for now
* splitting "[PATCH net-next 1/5] net: bridge: mcast: explicitly track active
state"
into:
* net: bridge: mcast: track active state, IGMP/MLD querier appearance
* net: bridge: mcast: track active state, foreign IGMP/MLD querier
disappearance
* net: bridge: mcast: track active state, IPv6 address availability
* net: bridge: mcast: track active state, own MLD querier disappearance
* net: bridge: mcast: use combined active state in fast/data path
* net: bridge: mcast: track active state, bridge up/down
* rebased to current net-next/main:
* from_timer() -> timer_container_of()
* net: bridge: mcast: export ip{4,6}_active state to netlink:
* changing NLA_U8 to NLA_REJECT to make it read-only
* moved br_multicast_update_active() call from
br_ip{4,6}_multicast_query_expired()
(own querier timer callback) to br_ip{4,6}_multicast_querier_expired()
(other querier timer callback)
* even though both should have worked as br_multicast_querier_expired()
would call br_multicast_start_querier()->...->br_multicast_query_expired(),
even if the own querier is disabled, but let's use the more direct way
* simplified br_multicast_update_active():
* no return value for now, don't track if the active state has changed,
these aren't necessary (yet)
* removed __br_multicast_update_active() variant as was used to force
an inactive state in __br_multicast_stop(), instead using an
netif_running(brmctx->br->dev) check in br_multicast_update_active()
* replaced br_ip{4,6}_multicast_check_active() with simpler
br_ip{4,6}_multicast_update_active() and
br_ip{4,6}_multicast_querier_exists()
* fixing build errors with CONFIG_IPV6 unset
* simplified br_multicast_toggle_enabled()
* no return value for now
* fixes "old used uninitialized" issue
* removed const from __br_multicast_querier_exists()'s "bool is_ipv6"
* replaced "struct ethhdr *eth" in br_multicast_{snooping,querier}_active()
with direct ethernet protocol integer attributes
* added a few comments in br_multicast_update_active() calling functions
