Re: [net-next v2 05/11] net: bridge: mcast: prepare is-router function for mcast router split

Nikolay Aleksandrov
2021-05-11T09:16:29Z

On 09/05/2021 22:45, Linus Lüssing wrote:
> In preparation for the upcoming split of multicast router state into
> their IPv4 and IPv6 variants make br_multicast_is_router() protocol
> family aware.
>
> Note that for now br_ip6_multicast_is_router() uses the currently still
> common ip4_mc_router_timer for now. It will be renamed to
> ip6_mc_router_timer later when the split is performed.
>
> While at it also renames the "1" and "2" constants in
> br_multicast_is_router() to the MDB_RTR_TYPE_TEMP_QUERY and
> MDB_RTR_TYPE_PERM enums.
>
> Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
> ---
> net/bridge/br_input.c | 2 +-
> net/bridge/br_multicast.c | 5 +++--
> net/bridge/br_private.h | 36 ++++++++++++++++++++++++++++++++----
> 3 files changed, 36 insertions(+), 7 deletions(-)
>

Minor comment below, but either way:
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>

> diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
> index 8875e95..1f50630 100644
> --- a/net/bridge/br_input.c
> +++ b/net/bridge/br_input.c
> @@ -132,7 +132,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
> if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
> br_multicast_querier_exists(br, eth_hdr(skb), mdst)) {
> if ((mdst && mdst->host_joined) ||
> - br_multicast_is_router(br)) {
> + br_multicast_is_router(br, skb)) {
> local_rcv = true;
> br->dev->stats.multicast++;
> }
> diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
> index 7edbbc9..048b5b9 100644
> --- a/net/bridge/br_multicast.c
> +++ b/net/bridge/br_multicast.c
> @@ -1391,7 +1391,8 @@ static void br_multicast_local_router_expired(struct timer_list *t)
> spin_lock(&br->multicast_lock);
> if (br->multicast_router == MDB_RTR_TYPE_DISABLED ||
> br->multicast_router == MDB_RTR_TYPE_PERM ||
> - timer_pending(&br->ip4_mc_router_timer))
> + br_ip4_multicast_is_router(br) ||
> + br_ip6_multicast_is_router(br))
> goto out;
>
> br_mc_router_state_change(br, false);
> @@ -3622,7 +3623,7 @@ bool br_multicast_router(const struct net_device *dev)
> bool is_router;
>
> spin_lock_bh(&br->multicast_lock);
> - is_router = br_multicast_is_router(br);
> + is_router = br_multicast_is_router(br, NULL);
> spin_unlock_bh(&br->multicast_lock);
> return is_router;
> }
> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> index 26e91d2..ac5ca5b 100644
> --- a/net/bridge/br_private.h
> +++ b/net/bridge/br_private.h
> @@ -864,11 +864,39 @@ static inline bool br_group_is_l2(const struct br_ip *group)
> #define mlock_dereference(X, br) \
> rcu_dereference_protected(X, lockdep_is_held(&br->multicast_lock))
>
> -static inline bool br_multicast_is_router(struct net_bridge *br)
> +static inline bool br_ip4_multicast_is_router(struct net_bridge *br)
> {
> - return br->multicast_router == 2 ||
> - (br->multicast_router == 1 &&
> - timer_pending(&br->ip4_mc_router_timer));
> + return timer_pending(&br->ip4_mc_router_timer);
> +}
> +
> +static inline bool br_ip6_multicast_is_router(struct net_bridge *br)
> +{
> +#if IS_ENABLED(CONFIG_IPV6)
> + return timer_pending(&br->ip4_mc_router_timer);
> +#else
> + return false;
> +#endif
> +}
> +
> +static inline bool
> +br_multicast_is_router(struct net_bridge *br, struct sk_buff *skb)
> +{
> + if (br->multicast_router == MDB_RTR_TYPE_PERM)
> + return true;
> +
> + if (br->multicast_router == MDB_RTR_TYPE_TEMP_QUERY) {
> + if (skb) {
> + if (skb->protocol == htons(ETH_P_IP))
> + return br_ip4_multicast_is_router(br);
> + else if (skb->protocol == htons(ETH_P_IPV6))
> + return br_ip6_multicast_is_router(br);
> + } else {
> + return br_ip4_multicast_is_router(br) ||
> + br_ip6_multicast_is_router(br);
> + }
> + }

Personally I'd prefer using a switch statement for br->multicast_router.

> +
> + return false;
> }
>
> static inline bool
>