Re: [PATCH] net: bridge: Allow bridge to joing multicast groups

[Vivien Didelot]

Hi Horatiu,

On Thu, 25 Jul 2019 13:44:04 +0200, Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx> wrote:
> There is no way to configure the bridge, to receive only specific link
> layer multicast addresses. From the description of the command 'bridge
> fdb append' is supposed to do that, but there was no way to notify the
> network driver that the bridge joined a group, because LLADDR was added
> to the unicast netdev_hw_addr_list.
> 
> Therefore update fdb_add_entry to check if the NLM_F_APPEND flag is set
> and if the source is NULL, which represent the bridge itself. Then add
> address to multicast netdev_hw_addr_list for each bridge interfaces.
> And then the .ndo_set_rx_mode function on the driver is called. To notify
> the driver that the list of multicast mac addresses changed.
> 
> Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
> ---
>  net/bridge/br_fdb.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 46 insertions(+), 3 deletions(-)
> 
> diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
> index b1d3248..d93746d 100644
> --- a/net/bridge/br_fdb.c
> +++ b/net/bridge/br_fdb.c
> @@ -175,6 +175,29 @@ static void fdb_add_hw_addr(struct net_bridge *br, const unsigned char *addr)
>  	}
>  }
>  
> +static void fdb_add_hw_maddr(struct net_bridge *br, const unsigned char *addr)
> +{
> +	int err;
> +	struct net_bridge_port *p;
> +
> +	ASSERT_RTNL();
> +
> +	list_for_each_entry(p, &br->port_list, list) {
> +		if (!br_promisc_port(p)) {
> +			err = dev_mc_add(p->dev, addr);
> +			if (err)
> +				goto undo;
> +		}
> +	}
> +
> +	return;
> +undo:
> +	list_for_each_entry_continue_reverse(p, &br->port_list, list) {
> +		if (!br_promisc_port(p))
> +			dev_mc_del(p->dev, addr);
> +	}
> +}
> +
>  /* When a static FDB entry is deleted, the HW address from that entry is
>   * also removed from the bridge private HW address list and updates all
>   * the ports with needed information.
> @@ -192,13 +215,27 @@ static void fdb_del_hw_addr(struct net_bridge *br, const unsigned char *addr)
>  	}
>  }
>  
> +static void fdb_del_hw_maddr(struct net_bridge *br, const unsigned char *addr)
> +{
> +	struct net_bridge_port *p;
> +
> +	ASSERT_RTNL();
> +
> +	list_for_each_entry(p, &br->port_list, list) {
> +		if (!br_promisc_port(p))
> +			dev_mc_del(p->dev, addr);
> +	}
> +}
> +
>  static void fdb_delete(struct net_bridge *br, struct net_bridge_fdb_entry *f,
>  		       bool swdev_notify)
>  {
>  	trace_fdb_delete(br, f);
>  
> -	if (f->is_static)
> +	if (f->is_static) {
>  		fdb_del_hw_addr(br, f->key.addr.addr);
> +		fdb_del_hw_maddr(br, f->key.addr.addr);
> +	}
>  
>  	hlist_del_init_rcu(&f->fdb_node);
>  	rhashtable_remove_fast(&br->fdb_hash_tbl, &f->rhnode,
> @@ -843,13 +880,19 @@ static int fdb_add_entry(struct net_bridge *br, struct net_bridge_port *source,
>  			fdb->is_local = 1;
>  			if (!fdb->is_static) {
>  				fdb->is_static = 1;
> -				fdb_add_hw_addr(br, addr);
> +				if (flags & NLM_F_APPEND && !source)
> +					fdb_add_hw_maddr(br, addr);
> +				else
> +					fdb_add_hw_addr(br, addr);
>  			}
>  		} else if (state & NUD_NOARP) {
>  			fdb->is_local = 0;
>  			if (!fdb->is_static) {
>  				fdb->is_static = 1;
> -				fdb_add_hw_addr(br, addr);
> +				if (flags & NLM_F_APPEND && !source)
> +					fdb_add_hw_maddr(br, addr);
> +				else
> +					fdb_add_hw_addr(br, addr);
>  			}
>  		} else {
>  			fdb->is_local = 0;
> -- 
> 2.7.4
> 

I'm a bit late in the conversation. Isn't this what you want?

    ip address add <multicast IPv4 address> dev br0 autojoin


Thanks,
Vivien