linux-kernel - [PATCH 6/6] bridge: Always multicast

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Message-ID: <20210504182259.5042-7-Joseph.Huang@garmin.com>
Date:   Tue, 4 May 2021 14:22:59 -0400
From:   Joseph Huang <Joseph.Huang@...min.com>
To:     Roopa Prabhu <roopa@...dia.com>,
        Nikolay Aleksandrov <nikolay@...dia.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        <bridge@...ts.linux-foundation.org>, <netdev@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
CC:     Joseph Huang <Joseph.Huang@...min.com>
Subject: [PATCH 6/6] bridge: Always multicast_flood Reports

Modify the forwarding path so that IGMPv1/2/MLDv1 Reports are always
flooded by br_multicast_flood, regardless of the check done
by br_multicast_querier_exists.

This patch fixes the problems where after a system boots up, the first
couple of Reports are not handled properly in that:

1) the Report from the Host is being flooded (via br_flood) to all
   bridge ports, and
2) if the mrouter port's mcast_flood is disabled, the Reports received
   from other hosts will not be forwarded to the Querier.

Signed-off-by: Joseph Huang <Joseph.Huang@...min.com>
---
 net/bridge/br_device.c    | 5 +++--
 net/bridge/br_input.c     | 5 +++--
 net/bridge/br_multicast.c | 3 +++
 net/bridge/br_private.h   | 3 +++
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index e8b626cc6bfd..ff75ba242f38 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -88,8 +88,9 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 		}
 
 		mdst = br_mdb_get(br, skb, vid);
-		if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
-		    br_multicast_querier_exists(br, eth_hdr(skb), mdst))
+		if (((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
+		    br_multicast_querier_exists(br, eth_hdr(skb), mdst)) ||
+		    BR_INPUT_SKB_CB_FORCE_MC_FLOOD(skb))
 			br_multicast_flood(mdst, skb, false, true);
 		else
 			br_flood(br, skb, BR_PKT_MULTICAST, false, true);
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 8875e953ac53..572d7f20477f 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -129,8 +129,9 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
 	switch (pkt_type) {
 	case BR_PKT_MULTICAST:
 		mdst = br_mdb_get(br, skb, vid);
-		if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
-		    br_multicast_querier_exists(br, eth_hdr(skb), mdst)) {
+		if (((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
+		    br_multicast_querier_exists(br, eth_hdr(skb), mdst)) ||
+		    BR_INPUT_SKB_CB_FORCE_MC_FLOOD(skb)) {
 			if ((mdst && mdst->host_joined) ||
 			    br_multicast_is_router(br)) {
 				local_rcv = true;
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index b7d9c491abe0..dfdbe19f3e93 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -3231,6 +3231,7 @@ static int br_multicast_ipv4_rcv(struct net_bridge *br,
 	case IGMP_HOST_MEMBERSHIP_REPORT:
 	case IGMPV2_HOST_MEMBERSHIP_REPORT:
 		BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
+		BR_INPUT_SKB_CB(skb)->force_mc_flood = 1;
 		err = br_ip4_multicast_add_group(br, port, ih->group, vid, src,
 						 true);
 		break;
@@ -3294,6 +3295,7 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br,
 	case ICMPV6_MGM_REPORT:
 		src = eth_hdr(skb)->h_source;
 		BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
+		BR_INPUT_SKB_CB(skb)->force_mc_flood = 1;
 		err = br_ip6_multicast_add_group(br, port, &mld->mld_mca, vid,
 						 src, true);
 		break;
@@ -3325,6 +3327,7 @@ int br_multicast_rcv(struct net_bridge *br, struct net_bridge_port *port,
 	BR_INPUT_SKB_CB(skb)->igmp = 0;
 	BR_INPUT_SKB_CB(skb)->mrouters_only = 0;
 	BR_INPUT_SKB_CB(skb)->force_flood = 0;
+	BR_INPUT_SKB_CB(skb)->force_mc_flood = 0;
 
 	if (!br_opt_get(br, BROPT_MULTICAST_ENABLED))
 		return 0;
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 59af599d48eb..6d4f20d7f482 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -492,6 +492,7 @@ struct br_input_skb_cb {
 	u8 igmp;
 	u8 mrouters_only:1;
 	u8 force_flood:1;
+	u8 force_mc_flood:1;
 #endif
 	u8 proxyarp_replied:1;
 	u8 src_port_isolated:1;
@@ -512,9 +513,11 @@ 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)
+# define BR_INPUT_SKB_CB_FORCE_MC_FLOOD(__skb)	(BR_INPUT_SKB_CB(__skb)->force_mc_flood)
 #else
 # define BR_INPUT_SKB_CB_MROUTERS_ONLY(__skb)	(0)
 # define BR_INPUT_SKB_CB_FORCE_FLOOD(__skb)		(0)
+# define BR_INPUT_SKB_CB_FORCE_MC_FLOOD(__skb)	(0)
 #endif
 
 #define br_printk(level, br, format, args...)	\
-- 
2.17.1