netdev - Re: [PATCH net v2 2/9] bridge: Fix the way to insert new local fdb entries in br_fdb

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Date:	Tue, 17 Dec 2013 11:00:33 -0500
From:	Vlad Yasevich <vyasevic@...hat.com>
To:	Toshiaki Makita <makita.toshiaki@....ntt.co.jp>,
	"David S . Miller" <davem@...emloft.net>,
	Stephen Hemminger <stephen@...workplumber.org>,
	Vlad Yasevich <vyasevic@...hat.com>, netdev@...r.kernel.org
Subject: Re: [PATCH net v2 2/9] bridge: Fix the way to insert new local fdb
 entries in br_fdb_changeaddr

On 12/17/2013 07:03 AM, Toshiaki Makita wrote:
> Since commit bc9a25d21ef8 ("bridge: Add vlan support for local fdb entries"),
> br_fdb_changeaddr() has inserted a new local fdb entry only if it can
> find old one. But if we have two ports where they have the same address
> or user has deleted a local entry, there will be no entry for one of the
> ports.
> 
> Example of problematic case:
>   ip link set eth0 address aa:bb:cc:dd:ee:ff
>   ip link set eth1 address aa:bb:cc:dd:ee:ff
>   brctl addif br0 eth0
>   brctl addif br0 eth1 # eth1 will not have a local entry due to dup.
>   ip link set eth1 address 12:34:56:78:90:ab
> Then, the new entry for the address 12:34:56:78:90:ab will not be
> created, and the bridge device will not be able to communicate.
> 
> Insert new entries regardless of whether we can find old entries or not.
> 
> Signed-off-by: Toshiaki Makita <makita.toshiaki@....ntt.co.jp>

Acked-by: Vlad Yasevich <vyasevic@...hat.com>

-vlad
> ---
>  net/bridge/br_fdb.c | 29 ++++++++++++++++++++---------
>  1 file changed, 20 insertions(+), 9 deletions(-)
> 
> diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
> index 5dab230..5f1bd11 100644
> --- a/net/bridge/br_fdb.c
> +++ b/net/bridge/br_fdb.c
> @@ -92,8 +92,10 @@ static void fdb_delete(struct net_bridge *br, struct net_bridge_fdb_entry *f)
>  void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
>  {
>  	struct net_bridge *br = p->br;
> -	bool no_vlan = (nbp_get_vlan_info(p) == NULL) ? true : false;
> +	struct net_port_vlans *pv = nbp_get_vlan_info(p);
> +	bool no_vlan = !pv;
>  	int i;
> +	u16 vid;
>  
>  	spin_lock_bh(&br->hash_lock);
>  
> @@ -114,28 +116,37 @@ void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
>  							     f->addr.addr) &&
>  					    nbp_vlan_find(op, vid)) {
>  						f->dst = op;
> -						goto insert;
> +						goto skip_delete;
>  					}
>  				}
>  
>  				/* delete old one */
>  				fdb_delete(br, f);
> -insert:
> -				/* insert new address,  may fail if invalid
> -				 * address or dup.
> -				 */
> -				fdb_insert(br, p, newaddr, vid);
> -
> +skip_delete:
>  				/* if this port has no vlan information
>  				 * configured, we can safely be done at
>  				 * this point.
>  				 */
>  				if (no_vlan)
> -					goto done;
> +					goto insert;
>  			}
>  		}
>  	}
>  
> +insert:
> +	/* insert new address,  may fail if invalid address or dup. */
> +	fdb_insert(br, p, newaddr, 0);
> +
> +	if (no_vlan)
> +		goto done;
> +
> +	/* Now add entries for every VLAN configured on the port.
> +	 * This function runs under RTNL so the bitmap will not change
> +	 * from under us.
> +	 */
> +	for_each_set_bit(vid, pv->vlan_bitmap, VLAN_N_VID)
> +		fdb_insert(br, p, newaddr, vid);
> +
>  done:
>  	spin_unlock_bh(&br->hash_lock);
>  }
> 

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