linux/net/dsa
Vladimir Oltean abd49535c3 net: dsa: execute dsa_switch_mdb_add only for routing port in cross-chip topologies
Currently, the notifier for adding a multicast MAC address matches on
the targeted port and on all DSA links in the system, be they upstream
or downstream links.

This leads to a considerable amount of useless traffic.

Consider this daisy chain topology, and a MDB add notifier emitted on
sw0p0. It matches on sw0p0, sw0p3, sw1p3 and sw2p4.

   sw0p0     sw0p1     sw0p2     sw0p3     sw0p4
[  user ] [  user ] [  user ] [  dsa  ] [  cpu  ]
[   x   ] [       ] [       ] [   x   ] [       ]
                                  |
                                  +---------+
                                            |
   sw1p0     sw1p1     sw1p2     sw1p3     sw1p4
[  user ] [  user ] [  user ] [  dsa  ] [  dsa  ]
[       ] [       ] [       ] [   x   ] [   x   ]
                                  |
                                  +---------+
                                            |
   sw2p0     sw2p1     sw2p2     sw2p3     sw2p4
[  user ] [  user ] [  user ] [  user ] [  dsa  ]
[       ] [       ] [       ] [       ] [   x   ]

But switch 0 has no reason to send the multicast traffic for that MAC
address on sw0p3, which is how it reaches switches 1 and 2. Those
switches don't expect, according to the user configuration, to receive
this multicast address from switch 1, and they will drop it anyway,
because the only valid destination is the port they received it on.
They only need to configure themselves to deliver that multicast address
_towards_ switch 1, where the MDB entry is installed.

Similarly, switch 1 should not send this multicast traffic towards
sw1p3, because that is how it reaches switch 2.

With this change, the heat map for this MDB notifier changes as follows:

   sw0p0     sw0p1     sw0p2     sw0p3     sw0p4
[  user ] [  user ] [  user ] [  dsa  ] [  cpu  ]
[   x   ] [       ] [       ] [       ] [       ]
                                  |
                                  +---------+
                                            |
   sw1p0     sw1p1     sw1p2     sw1p3     sw1p4
[  user ] [  user ] [  user ] [  dsa  ] [  dsa  ]
[       ] [       ] [       ] [       ] [   x   ]
                                  |
                                  +---------+
                                            |
   sw2p0     sw2p1     sw2p2     sw2p3     sw2p4
[  user ] [  user ] [  user ] [  user ] [  dsa  ]
[       ] [       ] [       ] [       ] [   x   ]

Now the mdb notifier behaves the same as the fdb notifier.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-21 12:50:20 -07:00
..
dsa2.c net: dsa: export the dsa_port_is_{user,cpu,dsa} helpers 2021-06-21 12:50:20 -07:00
dsa_priv.h net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
dsa.c net: dsa: allow changing the tag protocol via the "tagging" device attribute 2021-01-29 21:24:39 -08:00
Kconfig net: selftest: fix build issue if INET is disabled 2021-04-28 14:06:45 -07:00
Makefile net: dsa: add a second tagger for Ocelot switches based on tag_8021q 2021-01-29 21:25:27 -08:00
master.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
port.c net: dsa: fix bridge support for drivers without port_bridge_flags callback 2021-04-21 10:47:27 -07:00
slave.c net: dsa: dsa_slave_phy_connect(): extend phy's flags with port specific phy flags 2021-06-14 12:54:43 -07:00
switch.c net: dsa: execute dsa_switch_mdb_add only for routing port in cross-chip topologies 2021-06-21 12:50:20 -07:00
tag_8021q.c net: dsa: tag_8021q: refactor RX VLAN parsing into a dedicated function 2021-06-11 12:45:38 -07:00
tag_ar9331.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
tag_brcm.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
tag_dsa.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
tag_gswip.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
tag_hellcreek.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
tag_ksz.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
tag_lan9303.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
tag_mtk.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
tag_ocelot_8021q.c net: dsa: tag_8021q: refactor RX VLAN parsing into a dedicated function 2021-06-11 12:45:38 -07:00
tag_ocelot.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
tag_qca.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
tag_rtl4_a.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
tag_sja1105.c net: dsa: sja1105: implement TX timestamping for SJA1110 2021-06-11 12:45:38 -07:00
tag_trailer.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
tag_xrs700x.c net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00