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  1. 12 Dec, 2021 3 commits
    • Vladimir Oltean's avatar
      net: dsa: introduce tagger-owned storage for private and shared data · dc452a47
      Vladimir Oltean authored 
      Ansuel is working on register access over Ethernet for the qca8k switch
family. This requires the qca8k tagging protocol driver to receive
frames which aren't intended for the network stack, but instead for the
qca8k switch driver itself.

The dp->priv is currently the prevailing method for passing data back
and forth between the tagging protocol driver and the switch driver.
However, this method is riddled with caveats.

The DSA design allows in principle for any switch driver to return any
protocol it desires in ->get_tag_protocol(). The dsa_loop driver can be
modified to do just that. But in the current design, the memory behind
dp->priv has to be allocated by the switch driver, so if the tagging
protocol is paired to an unexpected switch driver, we may end up in NULL
pointer dereferences inside the kernel, or worse (a switch driver may
allocate dp->priv according to the expectations of a different tagger).

The latter possibility is even more plausible considering that DSA
switches can dynamically change tagging protocols in certain cases
(dsa <-> edsa, ocelot <-> ocelot-8021q), and the current design lends
itself to mistakes that are all too easy to make.

This patch proposes that the tagging protocol driver should manage its
own memory, instead of relying on the switch driver to do so.
After analyzing the different in-tree needs, it can be observed that the
required tagger storage is per switch, therefore a ds->tagger_data
pointer is introduced. In principle, per-port storage could also be
introduced, although there is no need for it at the moment. Future
changes will replace the current usage of dp->priv with ds->tagger_data.

We define a "binding" event between the DSA switch tree and the tagging
protocol. During this binding event, the tagging protocol's ->connect()
method is called first, and this may allocate some memory for each
switch of the tree. Then a cross-chip notifier is emitted for the
switches within that tree, and they are given the opportunity to fix up
the tagger's memory (for example, they might set up some function
pointers that represent virtual methods for consuming packets).
Because the memory is owned by the tagger, there exists a ->disconnect()
method for the tagger (which is the place to free the resources), but
there doesn't exist a ->disconnect() method for the switch driver.
This is part of the design. The switch driver should make minimal use of
the public part of the tagger data, and only after type-checking it
using the supplied "proto" argument.

In the code there are in fact two binding events, one is the initial
event in dsa_switch_setup_tag_protocol(). At this stage, the cross chip
notifier chains aren't initialized, so we call each switch's connect()
method by hand. Then there is dsa_tree_bind_tag_proto() during
dsa_tree_change_tag_proto(), and here we have an old protocol and a new
one. We first connect to the new one before disconnecting from the old
one, to simplify error handling a bit and to ensure we remain in a valid
state at all times.
Co-developed-by: default avatarAnsuel Smith <ansuelsmth@gmail.com>
Signed-off-by: default avatarAnsuel Smith <ansuelsmth@gmail.com>
Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      dc452a47
    • Tobias Waldekranz's avatar
      net: dsa: mv88e6xxx: Add tx fwd offload PVT on intermediate devices · e0068620
      Tobias Waldekranz authored 
      In a typical mv88e6xxx switch tree like this:

  CPU
   |    .----.
.--0--. | .--0--.
| sw0 | | | sw1 |
'-1-2-' | '-1-2-'
    '---'

If sw1p{1,2} are added to a bridge that sw0p1 is not a part of, sw0
still needs to add a crosschip PVT entry for the virtual DSA device
assigned to represent the bridge.

Fixes: ce5df689 ("net: dsa: mv88e6xxx: map virtual bridges with forwarding offload in the PVT")
Signed-off-by: default avatarTobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e0068620
    • xu xin's avatar
      net: Enable neighbor sysctls that is save for userns root · 8c8b7aa7
      xu xin authored 
      Inside netns owned by non-init userns, sysctls about ARP/neighbor is
currently not visible and configurable.

For the attributes these sysctls correspond to, any modifications make
effects on the performance of networking(ARP, especilly) only in the
scope of netns, which does not affect other netns.

Actually, some tools via netlink can modify these attribute. iproute2 is
an example. see as follows:

$ unshare -ur -n
$ cat /proc/sys/net/ipv4/neigh/lo/retrans_time
cat: can't open '/proc/sys/net/ipv4/neigh/lo/retrans_time': No such file
or directory
$ ip ntable show dev lo
inet arp_cache
    dev lo
    refcnt 1 reachable 19494 base_reachable 30000 retrans 1000
    gc_stale 60000 delay_probe 5000 queue 101
    app_probes 0 ucast_probes 3 mcast_probes 3
    anycast_delay 1000 proxy_delay 800 proxy_queue 64 locktime 1000

inet6 ndisc_cache
    dev lo
    refcnt 1 reachable 42394 base_reachable 30000 retrans 1000
    gc_stale 60000 delay_probe 5000 queue 101
    app_probes 0 ucast_probes 3 mcast_probes 3
    anycast_delay 1000 proxy_delay 800 proxy_queue 64 locktime 0
$ ip ntable change name arp_cache dev <if> retrans 2000
inet arp_cache
    dev lo
    refcnt 1 reachable 22917 base_reachable 30000 retrans 2000
    gc_stale 60000 delay_probe 5000 queue 101
    app_probes 0 ucast_probes 3 mcast_probes 3
    anycast_delay 1000 proxy_delay 800 proxy_queue 64 locktime 1000

inet6 ndisc_cache
    dev lo
    refcnt 1 reachable 35524 base_reachable 30000 retrans 1000
    gc_stale 60000 delay_probe 5000 queue 101
    app_probes 0 ucast_probes 3 mcast_probes 3
    anycast_delay 1000 proxy_delay 800 proxy_queue 64 locktime 0
Reported-by: default avatarZeal Robot <zealci@zte.com.cn>
Signed-off-by: default avatarxu xin <xu.xin16@zte.com.cn>
Acked-by: default avatarJoanne Koong <joannekoong@fb.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      8c8b7aa7
  3. 11 Dec, 2021 13 commits
  5. 10 Dec, 2021 24 commits
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