From 0adedb2da5372de54a9ff2fa7053aff7ba8e13cd Mon Sep 17 00:00:00 2001
From: Przemyslaw Bida <przemyslaw.bida@nordicsemi.no>
Date: Wed, 20 Oct 2021 09:01:52 +0200
Subject: [PATCH] [posix] add support for ipv6 group join in multicastrouter
 (#7116)

This commit adds support for joining and leaving multicast group in
order to send proper Multicast Listener Reports from thread network to
backbone link.
---
 src/posix/platform/multicast_routing.cpp | 23 +++++++++++++++++++++++
 src/posix/platform/multicast_routing.hpp |  1 +
 2 files changed, 24 insertions(+)

diff --git a/src/posix/platform/multicast_routing.cpp b/src/posix/platform/multicast_routing.cpp
index a5ef307c7..8759e3c2e 100644
--- a/src/posix/platform/multicast_routing.cpp
+++ b/src/posix/platform/multicast_routing.cpp
@@ -114,6 +114,8 @@ void MulticastRoutingManager::Add(const Ip6::Address &aAddress)
     VerifyOrExit(IsEnabled());
 
     UnblockInboundMulticastForwardingCache(aAddress);
+    UpdateMldReport(aAddress, true);
+
     otLogResultPlat(OT_ERROR_NONE, "MulticastRoutingManager: %s: %s", __FUNCTION__, aAddress.ToString().AsCString());
 
 exit:
@@ -127,12 +129,30 @@ void MulticastRoutingManager::Remove(const Ip6::Address &aAddress)
     VerifyOrExit(IsEnabled());
 
     RemoveInboundMulticastForwardingCache(aAddress);
+    UpdateMldReport(aAddress, false);
+
     otLogResultPlat(error, "MulticastRoutingManager: %s: %s", __FUNCTION__, aAddress.ToString().AsCString());
 
 exit:
     return;
 }
 
+void MulticastRoutingManager::UpdateMldReport(const Ip6::Address &aAddress, bool isAdd)
+{
+    struct ipv6_mreq ipv6mr;
+    otError          error = OT_ERROR_NONE;
+
+    ipv6mr.ipv6mr_interface = if_nametoindex(gBackboneNetifName);
+    memcpy(&ipv6mr.ipv6mr_multiaddr, aAddress.GetBytes(), sizeof(ipv6mr.ipv6mr_multiaddr));
+    error = (setsockopt(mMulticastRouterSock, IPPROTO_IPV6, (isAdd ? IPV6_JOIN_GROUP : IPV6_LEAVE_GROUP),
+                        (void *)&ipv6mr, sizeof(ipv6mr))
+                 ? OT_ERROR_FAILED
+                 : OT_ERROR_NONE);
+
+    otLogResultPlat(error, "MulticastRoutingManager: %s: address %s %s", __FUNCTION__, aAddress.ToString().AsCString(),
+                    (isAdd ? "Added" : "Removed"));
+}
+
 bool MulticastRoutingManager::HasMulticastListener(const Ip6::Address &aAddress) const
 {
     bool                                      found = false;
@@ -350,6 +370,7 @@ void MulticastRoutingManager::RemoveInboundMulticastForwardingCache(const Ip6::A
     {
         if (mfc.IsValid() && mfc.mIif == kMifIndexBackbone && mfc.mGroupAddr == aGroupAddr)
         {
+            UpdateMldReport(mfc.mGroupAddr, false);
             RemoveMulticastForwardingCache(mfc);
         }
     }
@@ -374,6 +395,7 @@ void MulticastRoutingManager::ExpireMulticastForwardingCache(void)
         {
             if (!UpdateMulticastRouteInfo(mfc))
             {
+                UpdateMldReport(mfc.mGroupAddr, false);
                 // The multicast route is expired
                 RemoveMulticastForwardingCache(mfc);
             }
@@ -539,6 +561,7 @@ void MulticastRoutingManager::SaveMulticastForwardingCache(const Ip6::Address &
     }
     else
     {
+        UpdateMldReport(oldest->mGroupAddr, false);
         RemoveMulticastForwardingCache(*oldest);
         oldest->Set(aSrcAddr, aGroupAddr, aIif, aOif);
     }
diff --git a/src/posix/platform/multicast_routing.hpp b/src/posix/platform/multicast_routing.hpp
index ec48d4c2b..72177d805 100644
--- a/src/posix/platform/multicast_routing.hpp
+++ b/src/posix/platform/multicast_routing.hpp
@@ -108,6 +108,7 @@ private:
     void    Disable(void);
     void    Add(const Ip6::Address &aAddress);
     void    Remove(const Ip6::Address &aAddress);
+    void    UpdateMldReport(const Ip6::Address &aAddress, bool isAdd);
     bool    HasMulticastListener(const Ip6::Address &aAddress) const;
     bool    IsEnabled(void) const { return mMulticastRouterSock >= 0; }
     void    InitMulticastRouterSock(void);