From e1d0f3f0839103bc5387d2fa78eb1fd9af2d1fe1 Mon Sep 17 00:00:00 2001 From: Yuyang Huang Date: Tue, 30 Jun 2026 20:02:06 +0900 Subject: [PATCH] net: ipv6: report multicast group user count The previous patch added IFA_MC_USERS and emits it for IPv4 multicast groups. Add the same snapshot attribute to IPv6 RTM_GETMULTICAST replies and entry-lifecycle notifications, carrying ifmcaddr6::mca_users. This makes the multicast rtnetlink ABI symmetric across IPv4 and IPv6 and gives userspace the same user count that /proc/net/igmp6 exposes. Signed-off-by: Yuyang Huang Reviewed-by: Vadim Fedorenko Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260630110207.37841-3-sigefriedhyy@gmail.com Signed-off-by: Paolo Abeni --- net/ipv6/addrconf.c | 1 + net/ipv6/mcast.c | 1 + 2 files changed, 2 insertions(+) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index cbe681de3818..f1fe9ede1edb 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -5264,6 +5264,7 @@ int inet6_fill_ifmcaddr(struct sk_buff *skb, put_ifaddrmsg(nlh, 128, IFA_F_PERMANENT, scope, ifindex); if (nla_put_in6_addr(skb, IFA_MULTICAST, &ifmca->mca_addr) < 0 || + nla_put_u32(skb, IFA_MC_USERS, READ_ONCE(ifmca->mca_users)) < 0 || put_cacheinfo(skb, ifmca->mca_cstamp, READ_ONCE(ifmca->mca_tstamp), INFINITY_LIFE_TIME, INFINITY_LIFE_TIME) < 0) { nlmsg_cancel(skb, nlh); diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 04b811b3be97..774f4c72a6fa 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -908,6 +908,7 @@ static void inet6_ifmcaddr_notify(struct net_device *dev, skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + nla_total_size(sizeof(struct in6_addr)) + + nla_total_size(sizeof(u32)) + nla_total_size(sizeof(struct ifa_cacheinfo)), GFP_KERNEL); if (!skb)