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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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2f5dc00f7a
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
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v
br_add_if() calls netdev_master_upper_dev_link()
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v
call_netdevice_notifiers
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v
dsa_slave_netdevice_event
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v
oh, hey! it's for me!
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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
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v
br_add_if() calls netdev_master_upper_dev_link()
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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.
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v |
oh, hey! it's for me! |
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v |
.port_bridge_join |
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+------------------------+
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
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v
br_add_if() calls netdev_master_upper_dev_link()
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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 |
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+------------------------+
switchdev_bridge_port_offload(bond0, swp3)
switchdev_bridge_port_offload(bond0, swp4)
And the non-offload case:
ip link set bond0 master br0
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v
br_add_if() calls netdev_master_upper_dev_link()
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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: Vladimir 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: David S. Miller <davem@davemloft.net>
230 lines
6 KiB
C
230 lines
6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Linux ethernet bridge
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*
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* Authors:
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* Lennert Buytenhek <buytenh@gnu.org>
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*/
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#ifndef _LINUX_IF_BRIDGE_H
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#define _LINUX_IF_BRIDGE_H
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#include <linux/netdevice.h>
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#include <uapi/linux/if_bridge.h>
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#include <linux/bitops.h>
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struct br_ip {
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union {
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__be32 ip4;
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#if IS_ENABLED(CONFIG_IPV6)
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struct in6_addr ip6;
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#endif
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} src;
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union {
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__be32 ip4;
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#if IS_ENABLED(CONFIG_IPV6)
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struct in6_addr ip6;
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#endif
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unsigned char mac_addr[ETH_ALEN];
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} dst;
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__be16 proto;
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__u16 vid;
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};
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struct br_ip_list {
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struct list_head list;
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struct br_ip addr;
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};
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#define BR_HAIRPIN_MODE BIT(0)
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#define BR_BPDU_GUARD BIT(1)
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#define BR_ROOT_BLOCK BIT(2)
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#define BR_MULTICAST_FAST_LEAVE BIT(3)
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#define BR_ADMIN_COST BIT(4)
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#define BR_LEARNING BIT(5)
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#define BR_FLOOD BIT(6)
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#define BR_AUTO_MASK (BR_FLOOD | BR_LEARNING)
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#define BR_PROMISC BIT(7)
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#define BR_PROXYARP BIT(8)
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#define BR_LEARNING_SYNC BIT(9)
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#define BR_PROXYARP_WIFI BIT(10)
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#define BR_MCAST_FLOOD BIT(11)
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#define BR_MULTICAST_TO_UNICAST BIT(12)
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#define BR_VLAN_TUNNEL BIT(13)
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#define BR_BCAST_FLOOD BIT(14)
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#define BR_NEIGH_SUPPRESS BIT(15)
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#define BR_ISOLATED BIT(16)
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#define BR_MRP_AWARE BIT(17)
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#define BR_MRP_LOST_CONT BIT(18)
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#define BR_MRP_LOST_IN_CONT BIT(19)
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#define BR_DEFAULT_AGEING_TIME (300 * HZ)
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extern void brioctl_set(int (*ioctl_hook)(struct net *, unsigned int, void __user *));
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#if IS_ENABLED(CONFIG_BRIDGE) && IS_ENABLED(CONFIG_BRIDGE_IGMP_SNOOPING)
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int br_multicast_list_adjacent(struct net_device *dev,
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struct list_head *br_ip_list);
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bool br_multicast_has_querier_anywhere(struct net_device *dev, int proto);
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bool br_multicast_has_querier_adjacent(struct net_device *dev, int proto);
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bool br_multicast_has_router_adjacent(struct net_device *dev, int proto);
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bool br_multicast_enabled(const struct net_device *dev);
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bool br_multicast_router(const struct net_device *dev);
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int br_mdb_replay(struct net_device *br_dev, struct net_device *dev,
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const void *ctx, bool adding, struct notifier_block *nb,
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struct netlink_ext_ack *extack);
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#else
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static inline int br_multicast_list_adjacent(struct net_device *dev,
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struct list_head *br_ip_list)
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{
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return 0;
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}
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static inline bool br_multicast_has_querier_anywhere(struct net_device *dev,
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int proto)
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{
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return false;
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}
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static inline bool br_multicast_has_querier_adjacent(struct net_device *dev,
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int proto)
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{
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return false;
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}
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static inline bool br_multicast_has_router_adjacent(struct net_device *dev,
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int proto)
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{
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return true;
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}
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static inline bool br_multicast_enabled(const struct net_device *dev)
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{
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return false;
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}
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static inline bool br_multicast_router(const struct net_device *dev)
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{
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return false;
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}
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static inline int br_mdb_replay(const struct net_device *br_dev,
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const struct net_device *dev, const void *ctx,
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bool adding, struct notifier_block *nb,
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struct netlink_ext_ack *extack)
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{
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return -EOPNOTSUPP;
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}
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#endif
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#if IS_ENABLED(CONFIG_BRIDGE) && IS_ENABLED(CONFIG_BRIDGE_VLAN_FILTERING)
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bool br_vlan_enabled(const struct net_device *dev);
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int br_vlan_get_pvid(const struct net_device *dev, u16 *p_pvid);
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int br_vlan_get_pvid_rcu(const struct net_device *dev, u16 *p_pvid);
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int br_vlan_get_proto(const struct net_device *dev, u16 *p_proto);
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int br_vlan_get_info(const struct net_device *dev, u16 vid,
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struct bridge_vlan_info *p_vinfo);
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int br_vlan_replay(struct net_device *br_dev, struct net_device *dev,
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const void *ctx, bool adding, struct notifier_block *nb,
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struct netlink_ext_ack *extack);
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#else
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static inline bool br_vlan_enabled(const struct net_device *dev)
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{
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return false;
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}
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static inline int br_vlan_get_pvid(const struct net_device *dev, u16 *p_pvid)
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{
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return -EINVAL;
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}
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static inline int br_vlan_get_proto(const struct net_device *dev, u16 *p_proto)
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{
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return -EINVAL;
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}
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static inline int br_vlan_get_pvid_rcu(const struct net_device *dev, u16 *p_pvid)
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{
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return -EINVAL;
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}
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static inline int br_vlan_get_info(const struct net_device *dev, u16 vid,
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struct bridge_vlan_info *p_vinfo)
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{
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return -EINVAL;
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}
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static inline int br_vlan_replay(struct net_device *br_dev,
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struct net_device *dev, const void *ctx,
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bool adding, struct notifier_block *nb,
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struct netlink_ext_ack *extack)
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{
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return -EOPNOTSUPP;
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}
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#endif
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#if IS_ENABLED(CONFIG_BRIDGE)
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struct net_device *br_fdb_find_port(const struct net_device *br_dev,
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const unsigned char *addr,
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__u16 vid);
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void br_fdb_clear_offload(const struct net_device *dev, u16 vid);
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bool br_port_flag_is_set(const struct net_device *dev, unsigned long flag);
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u8 br_port_get_stp_state(const struct net_device *dev);
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clock_t br_get_ageing_time(const struct net_device *br_dev);
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int br_fdb_replay(const struct net_device *br_dev, const struct net_device *dev,
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const void *ctx, bool adding, struct notifier_block *nb);
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#else
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static inline struct net_device *
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br_fdb_find_port(const struct net_device *br_dev,
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const unsigned char *addr,
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__u16 vid)
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{
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return NULL;
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}
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static inline void br_fdb_clear_offload(const struct net_device *dev, u16 vid)
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{
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}
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static inline bool
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br_port_flag_is_set(const struct net_device *dev, unsigned long flag)
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{
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return false;
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}
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static inline u8 br_port_get_stp_state(const struct net_device *dev)
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{
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return BR_STATE_DISABLED;
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}
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static inline clock_t br_get_ageing_time(const struct net_device *br_dev)
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{
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return 0;
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}
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static inline int br_fdb_replay(const struct net_device *br_dev,
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const struct net_device *dev, const void *ctx,
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bool adding, struct notifier_block *nb)
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{
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return -EOPNOTSUPP;
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}
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#endif
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#if IS_ENABLED(CONFIG_BRIDGE) && IS_ENABLED(CONFIG_NET_SWITCHDEV)
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int switchdev_bridge_port_offload(struct net_device *brport_dev,
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struct net_device *dev,
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struct netlink_ext_ack *extack);
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void switchdev_bridge_port_unoffload(struct net_device *brport_dev);
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#else
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static inline int switchdev_bridge_port_offload(struct net_device *brport_dev,
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struct net_device *dev,
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struct netlink_ext_ack *extack)
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{
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return -EINVAL;
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}
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static inline void switchdev_bridge_port_unoffload(struct net_device *brport_dev)
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{
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}
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#endif
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#endif
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