[Bridge] [PATCH] bridge: relay bridge multicast pkgs if !STP
Stephen Hemminger
shemminger at vyatta.com
Tue May 12 08:26:52 PDT 2009
On Tue, 12 May 2009 16:02:14 +0200
Joakim Tjernlund <Joakim.Tjernlund at transmode.se> wrote:
> Currently the bridge drops all STP pkgs when
> STP is off. This makes the bridge relay the Bridge Group
> multicast address, 01:80:c2:00:00:00, when STP is off.
> This allows for loop detection by other bridges doing STP.
>
> Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund at transmode.se>
> ---
> net/bridge/br_input.c | 14 +++++++++++++-
> 1 files changed, 13 insertions(+), 1 deletions(-)
>
> diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
> index 30b8877..8197823 100644
> --- a/net/bridge/br_input.c
> +++ b/net/bridge/br_input.c
> @@ -112,6 +112,17 @@ static inline int is_link_local(const unsigned char *dest)
> return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
> }
>
> +/* Does address match the Bride Group multicast address.
> + * 01:80:c2:00:00:00
> + */
> +static inline int is_bridge_group(const unsigned char *dest)
> +{
> + __be16 *a = (__be16 *)dest;
> + static const __be16 *b = (const __be16 *)br_group_address;
> +
> + return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) == 0;
> +}
> +
> /*
> * Called via br_handle_frame_hook.
> * Return NULL if skb is handled
> @@ -137,7 +148,8 @@ struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb)
> if (NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
> NULL, br_handle_local_finish))
> return NULL; /* frame consumed by filter */
> - else
> + /* Relay Bridge Group address is STP is off */
> + if (!(p->br->stp_enabled == BR_NO_STP && is_bridge_group(dest)))
> return skb; /* continue processing */
> }
>
First, you should have used compare_ether_addr.
Second, it needs to still obey state rules on port, so the return skb
should fall through to the switch statement.
--
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