[PATCH RFC net-next 01/10] net: bridge: Flood Queries even when mc flood is disabled

[Joseph Huang]

Modify the forwarding path so that received Queries are always flooded
even when multicast flooding is disabled on a bridge port.

In current implementation, when multicast flooding is disabled on a bridge
port, Queries received from other Querier will not be forwarded out of
that bridge port. This unfortunately breaks multicast snooping.

Signed-off-by: Joseph Huang <joseph.hu...@garmin.com>
---
 net/bridge/br_forward.c   | 3 ++-
 net/bridge/br_multicast.c | 3 +++
 net/bridge/br_private.h   | 3 +++
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 7431f89e897b..6c18ea37b5f5 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -216,7 +216,8 @@ void br_flood(struct net_bridge *br, struct sk_buff *skb,
                                continue;
                        break;
                case BR_PKT_MULTICAST:
-                       if (!(p->flags & BR_MCAST_FLOOD) && skb->dev != br->dev)
+                       if (!(p->flags & BR_MCAST_FLOOD) && skb->dev != br->dev 
&&
+                           !BR_INPUT_SKB_CB_FORCE_FLOOD(skb))
                                continue;
                        break;
                case BR_PKT_BROADCAST:
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 9a1cb5079a7a..42d900549227 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -3851,6 +3851,7 @@ static int br_multicast_ipv4_rcv(struct net_bridge_mcast 
*brmctx,
                err = br_ip4_multicast_igmp3_report(brmctx, pmctx, skb, vid);
                break;
        case IGMP_HOST_MEMBERSHIP_QUERY:
+               BR_INPUT_SKB_CB(skb)->force_flood = 1;
                br_ip4_multicast_query(brmctx, pmctx, skb, vid);
                break;
        case IGMP_HOST_LEAVE_MESSAGE:
@@ -3916,6 +3917,7 @@ static int br_multicast_ipv6_rcv(struct net_bridge_mcast 
*brmctx,
                err = br_ip6_multicast_mld2_report(brmctx, pmctx, skb, vid);
                break;
        case ICMPV6_MGM_QUERY:
+               BR_INPUT_SKB_CB(skb)->force_flood = 1;
                err = br_ip6_multicast_query(brmctx, pmctx, skb, vid);
                break;
        case ICMPV6_MGM_REDUCTION:
@@ -3941,6 +3943,7 @@ int br_multicast_rcv(struct net_bridge_mcast **brmctx,
 
        BR_INPUT_SKB_CB(skb)->igmp = 0;
        BR_INPUT_SKB_CB(skb)->mrouters_only = 0;
+       BR_INPUT_SKB_CB(skb)->force_flood = 0;
 
        if (!br_opt_get((*brmctx)->br, BROPT_MULTICAST_ENABLED))
                return 0;
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 86ea5e6689b5..c28e0cd0855c 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -586,6 +586,7 @@ struct br_input_skb_cb {
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
        u8 igmp;
        u8 mrouters_only:1;
+       u8 force_flood:1;
 #endif
        u8 proxyarp_replied:1;
        u8 src_port_isolated:1;
@@ -620,8 +621,10 @@ struct br_input_skb_cb {
 
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 # define BR_INPUT_SKB_CB_MROUTERS_ONLY(__skb)  
(BR_INPUT_SKB_CB(__skb)->mrouters_only)
+# define BR_INPUT_SKB_CB_FORCE_FLOOD(__skb)    
(BR_INPUT_SKB_CB(__skb)->force_flood)
 #else
 # define BR_INPUT_SKB_CB_MROUTERS_ONLY(__skb)  (0)
+# define BR_INPUT_SKB_CB_FORCE_FLOOD(__skb)    (0)
 #endif
 
 #define br_printk(level, br, format, args...)  \
-- 
2.17.1