From: Shengyu Qu Date: Mon, 14 Apr 2025 10:56:01 +0000 (+0800) Subject: net: bridge: locally receive all multicast packets if IFF_ALLMULTI is set X-Git-Tag: v6.16-rc1~132^2~290 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a496d2f0fd612ab9e10700afe00dc9267bad788b;p=thirdparty%2Fkernel%2Flinux.git net: bridge: locally receive all multicast packets if IFF_ALLMULTI is set If multicast snooping is enabled, multicast packets may not always end up on the local bridge interface, if the host is not a member of the multicast group. Similar to how IFF_PROMISC allows all packets to be received locally, let IFF_ALLMULTI allow all multicast packets to be received. OpenWrt uses a user space daemon for DHCPv6/RA/NDP handling, and in relay mode it sets the ALLMULTI flag in order to receive all relevant queries on the network. This works for normal network interfaces and non-snooping bridges, but not snooping bridges (unless multicast routing is enabled). Reported-by: Felix Fietkau Closes: https://github.com/openwrt/openwrt/issues/15857#issuecomment-2662851243 Signed-off-by: Shengyu Qu Reviewed-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/OSZPR01MB8434308370ACAFA90A22980798B32@OSZPR01MB8434.jpnprd01.prod.outlook.com Signed-off-by: Jakub Kicinski --- diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c index 232133a0fd21c..5f6ac9bf15275 100644 --- a/net/bridge/br_input.c +++ b/net/bridge/br_input.c @@ -189,7 +189,8 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) && br_multicast_querier_exists(brmctx, eth_hdr(skb), mdst)) { if ((mdst && mdst->host_joined) || - br_multicast_is_router(brmctx, skb)) { + br_multicast_is_router(brmctx, skb) || + br->dev->flags & IFF_ALLMULTI) { local_rcv = true; DEV_STATS_INC(br->dev, multicast); }