Re: [RFC net-next v4 8/9] bridge: mrp: Integrate MRP into the bridge

[Horatiu Vultur]

Hi Nik,

The 03/30/2020 19:16, Nikolay Aleksandrov wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On 27/03/2020 11:21, Horatiu Vultur wrote:
> > To integrate MRP into the bridge, the bridge needs to do the following:
> > - add new flag(BR_MPP_AWARE) to the net bridge ports, this bit will be set when
> >   the port is added to an MRP instance. In this way it knows if the frame was
> >   received on MRP ring port
> > - detect if the MRP frame was received on MRP ring port in that case it would be
> >   processed otherwise just forward it as usual.
> > - enable parsing of MRP
> > - before whenever the bridge was set up, it would set all the ports in
> >   forwarding state. Add an extra check to not set ports in forwarding state if
> >   the port is an MRP ring port. The reason of this change is that if the MRP
> >   instance initially sets the port in blocked state by setting the bridge up it
> >   would overwrite this setting.
> >
> > Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
> > ---
> >  include/linux/if_bridge.h |  1 +
> >  net/bridge/br_device.c    |  3 +++
> >  net/bridge/br_input.c     |  3 +++
> >  net/bridge/br_netlink.c   |  5 +++++
> >  net/bridge/br_private.h   | 22 ++++++++++++++++++++++
> >  net/bridge/br_stp.c       |  6 ++++++
> >  6 files changed, 40 insertions(+)
> >
> > diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
> > index 9e57c4411734..10baa9efdae8 100644
> > --- a/include/linux/if_bridge.h
> > +++ b/include/linux/if_bridge.h
> > @@ -47,6 +47,7 @@ struct br_ip_list {
> >  #define BR_BCAST_FLOOD               BIT(14)
> >  #define BR_NEIGH_SUPPRESS    BIT(15)
> >  #define BR_ISOLATED          BIT(16)
> > +#define BR_MRP_AWARE         BIT(17)
> >
> >  #define BR_DEFAULT_AGEING_TIME       (300 * HZ)
> >
> > diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
> > index 0e3dbc5f3c34..8ec1362588af 100644
> > --- a/net/bridge/br_device.c
> > +++ b/net/bridge/br_device.c
> > @@ -463,6 +463,9 @@ void br_dev_setup(struct net_device *dev)
> >       spin_lock_init(&br->lock);
> >       INIT_LIST_HEAD(&br->port_list);
> >       INIT_HLIST_HEAD(&br->fdb_list);
> > +#if IS_ENABLED(CONFIG_BRIDGE_MRP)
> > +     INIT_LIST_HEAD(&br->mrp_list);
> > +#endif
> >       spin_lock_init(&br->hash_lock);
> >
> >       br->bridge_id.prio[0] = 0x80;
> > diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
> > index fcc260840028..d5c34f36f0f4 100644
> > --- a/net/bridge/br_input.c
> > +++ b/net/bridge/br_input.c
> > @@ -342,6 +342,9 @@ rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
> >               }
> >       }
> >
> > +     if (unlikely(br_mrp_process(p, skb)))
> > +             return RX_HANDLER_PASS;
> > +
> >  forward:
> >       switch (p->state) {
> >       case BR_STATE_FORWARDING:
> > diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> > index 43dab4066f91..77bc96745be6 100644
> > --- a/net/bridge/br_netlink.c
> > +++ b/net/bridge/br_netlink.c
> > @@ -669,6 +669,11 @@ static int br_afspec(struct net_bridge *br,
> >                       if (err)
> >                               return err;
> >                       break;
> > +             case IFLA_BRIDGE_MRP:
> > +                     err = br_mrp_parse(br, p, attr, cmd);
> > +                     if (err)
> > +                             return err;
> > +                     break;
> >               }
> >       }
> >
> > diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> > index 1f97703a52ff..38894f2cf98f 100644
> > --- a/net/bridge/br_private.h
> > +++ b/net/bridge/br_private.h
> > @@ -428,6 +428,10 @@ struct net_bridge {
> >       int offload_fwd_mark;
> >  #endif
> >       struct hlist_head               fdb_list;
> > +
> > +#if IS_ENABLED(CONFIG_BRIDGE_MRP)
> > +     struct list_head                __rcu mrp_list;
> > +#endif
> >  };
> >
> >  struct br_input_skb_cb {
> > @@ -1304,6 +1308,24 @@ unsigned long br_timer_value(const struct timer_list *timer);
> >  extern int (*br_fdb_test_addr_hook)(struct net_device *dev, unsigned char *addr);
> >  #endif
> >
> > +/* br_mrp.c */
> > +#if IS_ENABLED(CONFIG_BRIDGE_MRP)
> > +int br_mrp_parse(struct net_bridge *br, struct net_bridge_port *p,
> > +              struct nlattr *attr, int cmd);
> > +int br_mrp_process(struct net_bridge_port *p, struct sk_buff *skb);
> > +#else
> > +static inline int br_mrp_parse(struct net_bridge *br, struct net_bridge_port *p,
> > +                            struct nlattr *attr, int cmd)
> > +{
> > +     return -1;
> 
> You should return proper error here.

It will return -EOPNOTSUPP.

> 
> > +}
> > +
> > +static inline int br_mrp_process(struct net_bridge_port *p, struct sk_buff *skb)
> > +{
> > +     return -1;
> 
> The bridge can't possibly work with MRP disabled with this.

Good catch, it will return 0.

> 
> > +}
> > +#endif
> > +
> >  /* br_netlink.c */
> >  extern struct rtnl_link_ops br_link_ops;
> >  int br_netlink_init(void);
> > diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
> > index 1f14b8455345..3e88be7aa269 100644
> > --- a/net/bridge/br_stp.c
> > +++ b/net/bridge/br_stp.c
> > @@ -36,6 +36,12 @@ void br_set_state(struct net_bridge_port *p, unsigned int state)
> >       };
> >       int err;
> >
> > +     /* Don't change the state of the ports if they are driven by a different
> > +      * protocol.
> > +      */
> > +     if (p->flags & BR_MRP_AWARE)
> > +             return;
> > +
> 
> Maybe disallow STP type (kernel/user-space/no-stp) changing as well, force it to no-stp.

I am not sure that I understand completely here, do you want me to
disable STP if MRP is started?

> 
> >       p->state = state;
> >       err = switchdev_port_attr_set(p->dev, &attr);
> >       if (err && err != -EOPNOTSUPP)
> >
> 

-- 
/Horatiu