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  1. 22 7月, 2021 4 次提交
    • V
      net: bridge: switchdev: let drivers inform which bridge ports are offloaded · 2f5dc00f
      由 Vladimir Oltean 提交于 
      On reception of an skb, the bridge checks if it was marked as 'already
forwarded in hardware' (checks if skb->offload_fwd_mark == 1), and if it
is, it assigns the source hardware domain of that skb based on the
hardware domain of the ingress port. Then during forwarding, it enforces
that the egress port must have a different hardware domain than the
ingress one (this is done in nbp_switchdev_allowed_egress).

Non-switchdev drivers don't report any physical switch id (neither
through devlink nor .ndo_get_port_parent_id), therefore the bridge
assigns them a hardware domain of 0, and packets coming from them will
always have skb->offload_fwd_mark = 0. So there aren't any restrictions.

Problems appear due to the fact that DSA would like to perform software
fallback for bonding and team interfaces that the physical switch cannot
offload.

       +-- br0 ---+
      / /   |      \
     / /    |       \
    /  |    |      bond0
   /   |    |     /    \
 swp0 swp1 swp2 swp3 swp4

There, it is desirable that the presence of swp3 and swp4 under a
non-offloaded LAG does not preclude us from doing hardware bridging
beteen swp0, swp1 and swp2. The bandwidth of the CPU is often times high
enough that software bridging between {swp0,swp1,swp2} and bond0 is not
impractical.

But this creates an impossible paradox given the current way in which
port hardware domains are assigned. When the driver receives a packet
from swp0 (say, due to flooding), it must set skb->offload_fwd_mark to
something.

- If we set it to 0, then the bridge will forward it towards swp1, swp2
  and bond0. But the switch has already forwarded it towards swp1 and
  swp2 (not to bond0, remember, that isn't offloaded, so as far as the
  switch is concerned, ports swp3 and swp4 are not looking up the FDB,
  and the entire bond0 is a destination that is strictly behind the
  CPU). But we don't want duplicated traffic towards swp1 and swp2, so
  it's not ok to set skb->offload_fwd_mark = 0.

- If we set it to 1, then the bridge will not forward the skb towards
  the ports with the same switchdev mark, i.e. not to swp1, swp2 and
  bond0. Towards swp1 and swp2 that's ok, but towards bond0? It should
  have forwarded the skb there.

So the real issue is that bond0 will be assigned the same hardware
domain as {swp0,swp1,swp2}, because the function that assigns hardware
domains to bridge ports, nbp_switchdev_add(), recurses through bond0's
lower interfaces until it finds something that implements devlink (calls
dev_get_port_parent_id with bool recurse = true). This is a problem
because the fact that bond0 can be offloaded by swp3 and swp4 in our
example is merely an assumption.

A solution is to give the bridge explicit hints as to what hardware
domain it should use for each port.

Currently, the bridging offload is very 'silent': a driver registers a
netdevice notifier, which is put on the netns's notifier chain, and
which sniffs around for NETDEV_CHANGEUPPER events where the upper is a
bridge, and the lower is an interface it knows about (one registered by
this driver, normally). Then, from within that notifier, it does a bunch
of stuff behind the bridge's back, without the bridge necessarily
knowing that there's somebody offloading that port. It looks like this:

     ip link set swp0 master br0
                  |
                  v
 br_add_if() calls netdev_master_upper_dev_link()
                  |
                  v
        call_netdevice_notifiers
                  |
                  v
       dsa_slave_netdevice_event
                  |
                  v
        oh, hey! it's for me!
                  |
                  v
           .port_bridge_join

What we do to solve the conundrum is to be less silent, and change the
switchdev drivers to present themselves to the bridge. Something like this:

     ip link set swp0 master br0
                  |
                  v
 br_add_if() calls netdev_master_upper_dev_link()
                  |
                  v                    bridge: Aye! I'll use this
        call_netdevice_notifiers           ^  ppid as the
                  |                        |  hardware domain for
                  v                        |  this port, and zero
       dsa_slave_netdevice_event           |  if I got nothing.
                  |                        |
                  v                        |
        oh, hey! it's for me!              |
                  |                        |
                  v                        |
           .port_bridge_join               |
                  |                        |
                  +------------------------+
             switchdev_bridge_port_offload(swp0, swp0)

Then stacked interfaces (like bond0 on top of swp3/swp4) would be
treated differently in DSA, depending on whether we can or cannot
offload them.

The offload case:

    ip link set bond0 master br0
                  |
                  v
 br_add_if() calls netdev_master_upper_dev_link()
                  |
                  v                    bridge: Aye! I'll use this
        call_netdevice_notifiers           ^  ppid as the
                  |                        |  switchdev mark for
                  v                        |        bond0.
       dsa_slave_netdevice_event           | Coincidentally (or not),
                  |                        | bond0 and swp0, swp1, swp2
                  v                        | all have the same switchdev
        hmm, it's not quite for me,        | mark now, since the ASIC
         but my driver has already         | is able to forward towards
           called .port_lag_join           | all these ports in hw.
          for it, because I have           |
      a port with dp->lag_dev == bond0.    |
                  |                        |
                  v                        |
           .port_bridge_join               |
           for swp3 and swp4               |
                  |                        |
                  +------------------------+
            switchdev_bridge_port_offload(bond0, swp3)
            switchdev_bridge_port_offload(bond0, swp4)

And the non-offload case:

    ip link set bond0 master br0
                  |
                  v
 br_add_if() calls netdev_master_upper_dev_link()
                  |
                  v                    bridge waiting:
        call_netdevice_notifiers           ^  huh, switchdev_bridge_port_offload
                  |                        |  wasn't called, okay, I'll use a
                  v                        |  hwdom of zero for this one.
       dsa_slave_netdevice_event           :  Then packets received on swp0 will
                  |                        :  not be software-forwarded towards
                  v                        :  swp1, but they will towards bond0.
         it's not for me, but
       bond0 is an upper of swp3
      and swp4, but their dp->lag_dev
       is NULL because they couldn't
            offload it.

Basically we can draw the conclusion that the lowers of a bridge port
can come and go, so depending on the configuration of lowers for a
bridge port, it can dynamically toggle between offloaded and unoffloaded.
Therefore, we need an equivalent switchdev_bridge_port_unoffload too.

This patch changes the way any switchdev driver interacts with the
bridge. From now on, everybody needs to call switchdev_bridge_port_offload
and switchdev_bridge_port_unoffload, otherwise the bridge will treat the
port as non-offloaded and allow software flooding to other ports from
the same ASIC.

Note that these functions lay the ground for a more complex handshake
between switchdev drivers and the bridge in the future.

For drivers that will request a replay of the switchdev objects when
they offload and unoffload a bridge port (DSA, dpaa2-switch, ocelot), we
place the call to switchdev_bridge_port_unoffload() strategically inside
the NETDEV_PRECHANGEUPPER notifier's code path, and not inside
NETDEV_CHANGEUPPER. This is because the switchdev object replay helpers
need the netdev adjacency lists to be valid, and that is only true in
NETDEV_PRECHANGEUPPER.

Cc: Vadym Kochan <vkochan@marvell.com>
Cc: Taras Chornyi <tchornyi@marvell.com>
Cc: Ioana Ciornei <ioana.ciornei@nxp.com>
Cc: Lars Povlsen <lars.povlsen@microchip.com>
Cc: Steen Hegelund <Steen.Hegelund@microchip.com>
Cc: UNGLinuxDriver@microchip.com
Cc: Claudiu Manoil <claudiu.manoil@nxp.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Ioana Ciornei <ioana.ciornei@nxp.com> # dpaa2-switch: regression
Acked-by: Ioana Ciornei <ioana.ciornei@nxp.com> # dpaa2-switch
Tested-by: Horatiu Vultur <horatiu.vultur@microchip.com> # ocelot-switch
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      2f5dc00f
    • T
      net: bridge: switchdev: recycle unused hwdoms · 85826610
      由 Tobias Waldekranz 提交于 
      Since hwdoms have only been used thus far for equality comparisons, the
bridge has used the simplest possible assignment policy; using a
counter to keep track of the last value handed out.

With the upcoming transmit offloading, we need to perform set
operations efficiently based on hwdoms, e.g. we want to answer
questions like "has this skb been forwarded to any port within this
hwdom?"

Move to a bitmap-based allocation scheme that recycles hwdoms once all
members leaves the bridge. This means that we can use a single
unsigned long to keep track of the hwdoms that have received an skb.

v1->v2: convert the typedef DECLARE_BITMAP(br_hwdom_map_t, BR_HWDOM_MAX)
        into a plain unsigned long.
v2->v6: none
Signed-off-by: NTobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      85826610
    • T
      net: bridge: disambiguate offload_fwd_mark · f7cf972f
      由 Tobias Waldekranz 提交于 
      Before this change, four related - but distinct - concepts where named
offload_fwd_mark:

- skb->offload_fwd_mark: Set by the switchdev driver if the underlying
  hardware has already forwarded this frame to the other ports in the
  same hardware domain.

- nbp->offload_fwd_mark: An idetifier used to group ports that share
  the same hardware forwarding domain.

- br->offload_fwd_mark: Counter used to make sure that unique IDs are
  used in cases where a bridge contains ports from multiple hardware
  domains.

- skb->cb->offload_fwd_mark: The hardware domain on which the frame
  ingressed and was forwarded.

Introduce the term "hardware forwarding domain" ("hwdom") in the
bridge to denote a set of ports with the following property:

    If an skb with skb->offload_fwd_mark set, is received on a port
    belonging to hwdom N, that frame has already been forwarded to all
    other ports in hwdom N.

By decoupling the name from "offload_fwd_mark", we can extend the
term's definition in the future - e.g. to add constraints that
describe expected egress behavior - without overloading the meaning of
"offload_fwd_mark".

- nbp->offload_fwd_mark thus becomes nbp->hwdom.

- br->offload_fwd_mark becomes br->last_hwdom.

- skb->cb->offload_fwd_mark becomes skb->cb->src_hwdom. The slight
  change in naming here mandates a slight change in behavior of the
  nbp_switchdev_frame_mark() function. Previously, it only set this
  value in skb->cb for packets with skb->offload_fwd_mark true (ones
  which were forwarded in hardware). Whereas now we always track the
  incoming hwdom for all packets coming from a switchdev (even for the
  packets which weren't forwarded in hardware, such as STP BPDUs, IGMP
  reports etc). As all uses of skb->cb->offload_fwd_mark were already
  gated behind checks of skb->offload_fwd_mark, this will not introduce
  any functional change, but it paves the way for future changes where
  the ingressing hwdom must be known for frames coming from a switchdev
  regardless of whether they were forwarded in hardware or not
  (basically, if the skb comes from a switchdev, skb->cb->src_hwdom now
  always tracks which one).

  A typical example where this is relevant: the switchdev has a fixed
  configuration to trap STP BPDUs, but STP is not running on the bridge
  and the group_fwd_mask allows them to be forwarded. Say we have this
  setup:

        br0
       / | \
      /  |  \
  swp0 swp1 swp2

  A BPDU comes in on swp0 and is trapped to the CPU; the driver does not
  set skb->offload_fwd_mark. The bridge determines that the frame should
  be forwarded to swp{1,2}. It is imperative that forward offloading is
  _not_ allowed in this case, as the source hwdom is already "poisoned".

  Recording the source hwdom allows this case to be handled properly.

v2->v3: added code comments
v3->v6: none
Signed-off-by: NTobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      f7cf972f
    • N
      net: bridge: multicast: add context support for host-joined groups · 58d913a3
      由 Nikolay Aleksandrov 提交于 
      Adding bridge multicast context support for host-joined groups is easy
because we only need the proper timer value. We pass the already chosen
context and use its timer value.
Signed-off-by: NNikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      58d913a3
  3. 20 7月, 2021 11 次提交
  5. 30 6月, 2021 1 次提交
  7. 11 6月, 2021 1 次提交
    • N
      net: bridge: fix vlan tunnel dst null pointer dereference · 58e20717
      由 Nikolay Aleksandrov 提交于 
      This patch fixes a tunnel_dst null pointer dereference due to lockless
access in the tunnel egress path. When deleting a vlan tunnel the
tunnel_dst pointer is set to NULL without waiting a grace period (i.e.
while it's still usable) and packets egressing are dereferencing it
without checking. Use READ/WRITE_ONCE to annotate the lockless use of
tunnel_id, use RCU for accessing tunnel_dst and make sure it is read
only once and checked in the egress path. The dst is already properly RCU
protected so we don't need to do anything fancy than to make sure
tunnel_id and tunnel_dst are read only once and checked in the egress path.

Cc: stable@vger.kernel.org
Fixes: 11538d03 ("bridge: vlan dst_metadata hooks in ingress and egress paths")
Signed-off-by: NNikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      58e20717
  9. 15 5月, 2021 1 次提交
  11. 14 5月, 2021 4 次提交
  13. 15 4月, 2021 1 次提交
  15. 25 3月, 2021 1 次提交
  17. 16 2月, 2021 1 次提交
  19. 15 2月, 2021 3 次提交
  21. 13 2月, 2021 1 次提交
  23. 28 1月, 2021 1 次提交
  25. 23 1月, 2021 3 次提交
  27. 08 12月, 2020 1 次提交
    • J
      bridge: Fix a deadlock when enabling multicast snooping · 851d0a73
      由 Joseph Huang 提交于 
      When enabling multicast snooping, bridge module deadlocks on multicast_lock
if 1) IPv6 is enabled, and 2) there is an existing querier on the same L2
network.

The deadlock was caused by the following sequence: While holding the lock,
br_multicast_open calls br_multicast_join_snoopers, which eventually causes
IP stack to (attempt to) send out a Listener Report (in igmp6_join_group).
Since the destination Ethernet address is a multicast address, br_dev_xmit
feeds the packet back to the bridge via br_multicast_rcv, which in turn
calls br_multicast_add_group, which then deadlocks on multicast_lock.

The fix is to move the call br_multicast_join_snoopers outside of the
critical section. This works since br_multicast_join_snoopers only deals
with IP and does not modify any multicast data structures of the bridge,
so there's no need to hold the lock.

Steps to reproduce:
1. sysctl net.ipv6.conf.all.force_mld_version=1
2. have another querier
3. ip link set dev bridge type bridge mcast_snooping 0 && \
   ip link set dev bridge type bridge mcast_snooping 1 < deadlock >

A typical call trace looks like the following:

[  936.251495]  _raw_spin_lock+0x5c/0x68
[  936.255221]  br_multicast_add_group+0x40/0x170 [bridge]
[  936.260491]  br_multicast_rcv+0x7ac/0xe30 [bridge]
[  936.265322]  br_dev_xmit+0x140/0x368 [bridge]
[  936.269689]  dev_hard_start_xmit+0x94/0x158
[  936.273876]  __dev_queue_xmit+0x5ac/0x7f8
[  936.277890]  dev_queue_xmit+0x10/0x18
[  936.281563]  neigh_resolve_output+0xec/0x198
[  936.285845]  ip6_finish_output2+0x240/0x710
[  936.290039]  __ip6_finish_output+0x130/0x170
[  936.294318]  ip6_output+0x6c/0x1c8
[  936.297731]  NF_HOOK.constprop.0+0xd8/0xe8
[  936.301834]  igmp6_send+0x358/0x558
[  936.305326]  igmp6_join_group.part.0+0x30/0xf0
[  936.309774]  igmp6_group_added+0xfc/0x110
[  936.313787]  __ipv6_dev_mc_inc+0x1a4/0x290
[  936.317885]  ipv6_dev_mc_inc+0x10/0x18
[  936.321677]  br_multicast_open+0xbc/0x110 [bridge]
[  936.326506]  br_multicast_toggle+0xec/0x140 [bridge]

Fixes: 4effd28c ("bridge: join all-snoopers multicast address")
Signed-off-by: NJoseph Huang <Joseph.Huang@garmin.com>
Acked-by: NNikolay Aleksandrov <nikolay@nvidia.com>
Link: https://lore.kernel.org/r/20201204235628.50653-1-Joseph.Huang@garmin.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>
      851d0a73
  29. 22 11月, 2020 1 次提交
  31. 19 11月, 2020 1 次提交
  33. 10 11月, 2020 1 次提交
  35. 01 11月, 2020 1 次提交
  37. 31 10月, 2020 1 次提交
  39. 30 10月, 2020 1 次提交
    • H
      bridge: cfm: Netlink Notifications. · b6d0425b
      由 Henrik Bjoernlund 提交于 
      This is the implementation of Netlink notifications out of CFM.

Notifications are initiated whenever a state change happens in CFM.

IFLA_BRIDGE_CFM:
    Points to the CFM information.

IFLA_BRIDGE_CFM_MEP_STATUS_INFO:
    This indicate that the MEP instance status are following.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_INFO:
    This indicate that the peer MEP status are following.

CFM nested attribute has the following attributes in next level.

IFLA_BRIDGE_CFM_MEP_STATUS_INSTANCE:
    The MEP instance number of the delivered status.
    The type is NLA_U32.
IFLA_BRIDGE_CFM_MEP_STATUS_OPCODE_UNEXP_SEEN:
    The MEP instance received CFM PDU with unexpected Opcode.
    The type is NLA_U32 (bool).
IFLA_BRIDGE_CFM_MEP_STATUS_VERSION_UNEXP_SEEN:
    The MEP instance received CFM PDU with unexpected version.
    The type is NLA_U32 (bool).
IFLA_BRIDGE_CFM_MEP_STATUS_RX_LEVEL_LOW_SEEN:
    The MEP instance received CCM PDU with MD level lower than
    configured level. This frame is discarded.
    The type is NLA_U32 (bool).

IFLA_BRIDGE_CFM_CC_PEER_STATUS_INSTANCE:
    The MEP instance number of the delivered status.
    The type is NLA_U32.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_PEER_MEPID:
    The added Peer MEP ID of the delivered status.
    The type is NLA_U32.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_CCM_DEFECT:
    The CCM defect status.
    The type is NLA_U32 (bool).
    True means no CCM frame is received for 3.25 intervals.
    IFLA_BRIDGE_CFM_CC_CONFIG_EXP_INTERVAL.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_RDI:
    The last received CCM PDU RDI.
    The type is NLA_U32 (bool).
IFLA_BRIDGE_CFM_CC_PEER_STATUS_PORT_TLV_VALUE:
    The last received CCM PDU Port Status TLV value field.
    The type is NLA_U8.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_IF_TLV_VALUE:
    The last received CCM PDU Interface Status TLV value field.
    The type is NLA_U8.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_SEEN:
    A CCM frame has been received from Peer MEP.
    The type is NLA_U32 (bool).
    This is cleared after GETLINK IFLA_BRIDGE_CFM_CC_PEER_STATUS_INFO.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_TLV_SEEN:
    A CCM frame with TLV has been received from Peer MEP.
    The type is NLA_U32 (bool).
    This is cleared after GETLINK IFLA_BRIDGE_CFM_CC_PEER_STATUS_INFO.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_SEQ_UNEXP_SEEN:
    A CCM frame with unexpected sequence number has been received
    from Peer MEP.
    The type is NLA_U32 (bool).
    When a sequence number is not one higher than previously received
    then it is unexpected.
    This is cleared after GETLINK IFLA_BRIDGE_CFM_CC_PEER_STATUS_INFO.
Signed-off-by: NHenrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: NHoratiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: NNikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
      b6d0425b