Re: [RFC net-next] net: bridge: igmp: Extend IGMP query with vlan support

[Horatiu Vultur]

The 12/11/2020 11:46, Nikolay Aleksandrov wrote:
> 
> On 11/12/2020 11:26, Horatiu Vultur wrote:
> > This patch tries to add vlan support to IGMP queries.
> > It extends the function 'br_ip4_multicast_alloc_query' to add
> > also a vlan tag if vlan is enabled. Therefore the bridge will send
> > queries for each vlan the ports are in.
> >
> > There are few other places that needs to be updated to be fully
> > functional. But I am curious if this is the way to go forward or is
> > there a different way of implementing this?
> >
> > Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
> > ---
> >  net/bridge/br_multicast.c | 31 ++++++++++++++++++++++++++-----
> >  1 file changed, 26 insertions(+), 5 deletions(-)
> >

Hi Nik,

> 
> Hi Horatiu,
> We've discussed this with other people on netdev before, the way forward is to
> implement it as a per-vlan option and then have a per-vlan querier. Which would also
> make the change much bigger and more complex. In general some of the multicast options
> need to be replicated for vlans to get proper per-vlan multicast control and operation, but
> that would require to change a lot of logic around the whole bridge (fast-path included,
> where it'd be most sensitive).

Thanks for the suggestion and for the heads up. I will have a look and
see how to do it like you mention.


> The good news is that these days we have per-vlan options
> support and so only the actual per-vlan multicast implementation is left to be done.
> I have this on my TODO list, unfortunately that list gets longer and longer,
> so I'd be happy to review patches if someone decides to do it sooner. :)

That would be much appreciated :).

> 
> Sorry, I couldn't find the previous discussion, it was a few years back.
> 
> Cheers,
>  Nik
> 
> > diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
> > index 484820c223a3..4c2db8a9efe0 100644
> > --- a/net/bridge/br_multicast.c
> > +++ b/net/bridge/br_multicast.c
> > @@ -688,7 +688,8 @@ static struct sk_buff *br_ip4_multicast_alloc_query(struct net_bridge *br,
> >                                                   __be32 ip_dst, __be32 group,
> >                                                   bool with_srcs, bool over_lmqt,
> >                                                   u8 sflag, u8 *igmp_type,
> > -                                                 bool *need_rexmit)
> > +                                                 bool *need_rexmit,
> > +                                                 __u16 vid)
> >  {
> >       struct net_bridge_port *p = pg ? pg->key.port : NULL;
> >       struct net_bridge_group_src *ent;
> > @@ -724,6 +725,9 @@ static struct sk_buff *br_ip4_multicast_alloc_query(struct net_bridge *br,
> >       }
> >
> >       pkt_size = sizeof(*eth) + sizeof(*iph) + 4 + igmp_hdr_size;
> > +     if (br_vlan_enabled(br->dev) && vid != 0)
> > +             pkt_size += 4;
> > +
> >       if ((p && pkt_size > p->dev->mtu) ||
> >           pkt_size > br->dev->mtu)
> >               return NULL;
> > @@ -732,6 +736,9 @@ static struct sk_buff *br_ip4_multicast_alloc_query(struct net_bridge *br,
> >       if (!skb)
> >               goto out;
> >
> > +     if (br_vlan_enabled(br->dev) && vid != 0)
> > +             __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vid);
> > +
> >       skb->protocol = htons(ETH_P_IP);
> >
> >       skb_reset_mac_header(skb);
> > @@ -1008,7 +1015,8 @@ static struct sk_buff *br_multicast_alloc_query(struct net_bridge *br,
> >                                                   ip4_dst, group->dst.ip4,
> >                                                   with_srcs, over_lmqt,
> >                                                   sflag, igmp_type,
> > -                                                 need_rexmit);
> > +                                                 need_rexmit,
> > +                                                 group->vid);
> >  #if IS_ENABLED(CONFIG_IPV6)
> >       case htons(ETH_P_IPV6): {
> >               struct in6_addr ip6_dst;
> > @@ -1477,6 +1485,8 @@ static void br_multicast_send_query(struct net_bridge *br,
> >                                   struct bridge_mcast_own_query *own_query)
> >  {
> >       struct bridge_mcast_other_query *other_query = NULL;
> > +     struct net_bridge_vlan_group *vg;
> > +     struct net_bridge_vlan *v;
> >       struct br_ip br_group;
> >       unsigned long time;
> >
> > @@ -1485,7 +1495,7 @@ static void br_multicast_send_query(struct net_bridge *br,
> >           !br_opt_get(br, BROPT_MULTICAST_QUERIER))
> >               return;
> >
> > -     memset(&br_group.dst, 0, sizeof(br_group.dst));
> > +     memset(&br_group, 0, sizeof(br_group));
> >
> >       if (port ? (own_query == &port->ip4_own_query) :
> >                  (own_query == &br->ip4_own_query)) {
> > @@ -1501,8 +1511,19 @@ static void br_multicast_send_query(struct net_bridge *br,
> >       if (!other_query || timer_pending(&other_query->timer))
> >               return;
> >
> > -     __br_multicast_send_query(br, port, NULL, NULL, &br_group, false, 0,
> > -                               NULL);
> > +     if (br_vlan_enabled(br->dev) && port) {
> > +             vg = nbp_vlan_group(port);
> > +
> > +             list_for_each_entry(v, &vg->vlan_list, vlist) {
> > +                     br_group.vid = v->vid == vg->pvid ? 0 : v->vid;
> > +
> > +                     __br_multicast_send_query(br, port, NULL, NULL,
> > +                                               &br_group, false, 0, NULL);
> > +             }
> > +     } else {
> > +             __br_multicast_send_query(br, port, NULL, NULL, &br_group,
> > +                                       false, 0, NULL);
> > +     }
> >
> >       time = jiffies;
> >       time += own_query->startup_sent < br->multicast_startup_query_count ?
> >
> 

-- 
/Horatiu