Vladimir Oltean c73c57081b net: dsa: don't disable multicast flooding to the CPU even without an IGMP querier ... Commit 08cc83cc7f ("net: dsa: add support for BRIDGE_MROUTER attribute") added an option for users to turn off multicast flooding towards the CPU if they turn off the IGMP querier on a bridge which already has enslaved ports (echo 0 > /sys/class/net/br0/bridge/multicast_router). And commit a8b659e7ff ("net: dsa: act as passthrough for bridge port flags") simply papered over that issue, because it moved the decision to flood the CPU with multicast (or not) from the DSA core down to individual drivers, instead of taking a more radical position then. The truth is that disabling multicast flooding to the CPU is simply something we are not prepared to do now, if at all. Some reasons: - ICMP6 neighbor solicitation messages are unregistered multicast packets as far as the bridge is concerned. So if we stop flooding multicast, the outside world cannot ping the bridge device's IPv6 link-local address. - There might be foreign interfaces bridged with our DSA switch ports (sending a packet towards the host does not necessarily equal termination, but maybe software forwarding). So if there is no one interested in that multicast traffic in the local network stack, that doesn't mean nobody is. - PTP over L4 (IPv4, IPv6) is multicast, but is unregistered as far as the bridge is concerned. This should reach the CPU port. - The switch driver might not do FDB partitioning. And since we don't even bother to do more fine-grained flood disabling (such as "disable flooding _from_port_N_ towards the CPU port" as opposed to "disable flooding _from_any_port_ towards the CPU port"), this breaks standalone ports, or even multiple bridges where one has an IGMP querier and one doesn't. Reverting the logic makes all of the above work. Fixes: a8b659e7ff ("net: dsa: act as passthrough for bridge port flags") Fixes: 08cc83cc7f ("net: dsa: add support for BRIDGE_MROUTER attribute") Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2021-08-06 11:11:13 +01:00
..
acpi	ACPI: fix NULL pointer dereference	2021-07-24 15:25:54 -07:00
asm-generic	compat: make linux/compat.h available everywhere	2021-07-23 14:20:24 +01:00
clocksource
crypto
drm	drm: Return -ENOTTY for non-drm ioctls	2021-07-20 15:57:43 +02:00
dt-bindings	dt-bindings: clock: r9a07g044-cpg: Update clock/reset definitions	2021-07-12 10:52:03 +02:00
keys
kunit	linux-kselftest-kunit-fixes-5.14-rc1	2021-07-02 12:58:26 -07:00
kvm
linux	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2021-08-05 15:08:47 -07:00
math-emu	math-emu: Fix fall-through warning	2021-07-13 13:57:44 -05:00
media
memory
misc
net	net: dsa: don't disable multicast flooding to the CPU even without an IGMP querier	2021-08-06 11:11:13 +01:00
pcmcia
ras
rdma
scsi	SCSI misc on 20210702	2021-07-02 15:14:36 -07:00
soc	Memory controller drivers for v5.14 - Tegra SoC, late fixes	2021-07-16 22:51:01 +02:00
sound	ASoC: Fixes for v5.14	2021-07-21 19:48:09 +02:00
target
trace	qdisc: add new field for qdisc_enqueue tracepoint	2021-07-27 14:16:38 +01:00
uapi	net/ipv4/ipv6: Replace one-element arraya with flexible-array members	2021-08-05 11:46:42 +01:00
vdso
video
xen	xen: sync include/xen/interface/io/ring.h with Xen's newest version	2021-07-05 09:49:45 +02:00