Linux Ethernet Bridging - Apr 2022 - [Bridge] [PATCH net-next 3/6] net: bridge: fdb: add new nl attribute-based flush call

Add a new fdb flush call which parses the embedded attributes in
BRIDGE_FLUSH_FDB and fills in the fdb flush descriptor to delete only
matching entries. Currently it's a complete flush, support for more
fine-grained filtering will be added in the following patches.

Signed-off-by: Nikolay Aleksandrov <razor at blackwall.org>
---
 include/uapi/linux/if_bridge.h |  8 ++++++++
 net/bridge/br_fdb.c            | 24 ++++++++++++++++++++++++
 net/bridge/br_netlink.c        |  8 ++++++++
 net/bridge/br_private.h        |  2 ++
 4 files changed, 42 insertions(+)

diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index 221a4256808f..2f3799cf14b2 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -807,7 +807,15 @@ enum {
 /* embedded in IFLA_BRIDGE_FLUSH */
 enum {
 	BRIDGE_FLUSH_UNSPEC,
+	BRIDGE_FLUSH_FDB,
 	__BRIDGE_FLUSH_MAX
 };
 #define BRIDGE_FLUSH_MAX (__BRIDGE_FLUSH_MAX - 1)
+
+/* embedded in BRIDGE_FLUSH_FDB */
+enum {
+	FDB_FLUSH_UNSPEC,
+	__FDB_FLUSH_MAX
+};
+#define FDB_FLUSH_MAX (__FDB_FLUSH_MAX - 1)
 #endif /* _UAPI_LINUX_IF_BRIDGE_H */
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 4b0bf88c4121..62f694a739e1 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -594,6 +594,30 @@ void br_fdb_flush(struct net_bridge *br,
 	rcu_read_unlock();
 }
 
+static const struct nla_policy br_fdb_flush_policy[FDB_FLUSH_MAX + 1] = {
+	[FDB_FLUSH_UNSPEC]	= { .type = NLA_REJECT },
+};
+
+int br_fdb_flush_nlattr(struct net_bridge *br, struct nlattr *fdb_flush_attr,
+			struct netlink_ext_ack *extack)
+{
+	struct nlattr *fdb_flush_tb[FDB_FLUSH_MAX + 1];
+	struct net_bridge_fdb_flush_desc desc = {};
+	int err;
+
+	err = nla_parse_nested(fdb_flush_tb, FDB_FLUSH_MAX, fdb_flush_attr,
+			       br_fdb_flush_policy, extack);
+	if (err)
+		return err;
+
+	br_debug(br, "flushing port ifindex: %d vlan id: %u flags: 0x%lx flags
mask: 0x%lx\n",
+		 desc.port_ifindex, desc.vlan_id, desc.flags, desc.flags_mask);
+
+	br_fdb_flush(br, &desc);
+
+	return 0;
+}
+
 /* Flush all entries referring to a specific port.
  * if do_all is set also flush static entries
  * if vid is set delete all entries that match the vlan_id
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 6e6dce6880c9..bd2c91e5723d 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -781,6 +781,7 @@ int br_process_vlan_info(struct net_bridge *br,
 
 static const struct nla_policy br_flush_policy[BRIDGE_FLUSH_MAX + 1] = {
 	[BRIDGE_FLUSH_UNSPEC]	= { .type = NLA_REJECT },
+	[BRIDGE_FLUSH_FDB]	= { .type = NLA_NESTED },
 };
 
 static int br_flush(struct net_bridge *br, int cmd,
@@ -804,6 +805,13 @@ static int br_flush(struct net_bridge *br, int cmd,
 	if (err)
 		return err;
 
+	if (flush_tb[BRIDGE_FLUSH_FDB]) {
+		err = br_fdb_flush_nlattr(br, flush_tb[BRIDGE_FLUSH_FDB],
+					  extack);
+		if (err)
+			return err;
+	}
+
 	return 0;
 }
 
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index e6930e9ee69d..c7ea531d30ef 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -768,6 +768,8 @@ int br_fdb_hash_init(struct net_bridge *br);
 void br_fdb_hash_fini(struct net_bridge *br);
 void br_fdb_flush(struct net_bridge *br,
 		  const struct net_bridge_fdb_flush_desc *desc);
+int br_fdb_flush_nlattr(struct net_bridge *br, struct nlattr *fdb_flush_attr,
+			struct netlink_ext_ack *extack);
 void br_fdb_find_delete_local(struct net_bridge *br,
 			      const struct net_bridge_port *p,
 			      const unsigned char *addr, u16 vid);
-- 
2.35.1

On Sat, Apr 09, 2022 at 01:58:54PM +0300, Nikolay Aleksandrov
wrote:
> Add a new fdb flush call which parses the embedded attributes in
> BRIDGE_FLUSH_FDB and fills in the fdb flush descriptor to delete only
> matching entries. Currently it's a complete flush, support for more
> fine-grained filtering will be added in the following patches.
> 
> Signed-off-by: Nikolay Aleksandrov <razor at blackwall.org>
> ---
>  include/uapi/linux/if_bridge.h |  8 ++++++++
>  net/bridge/br_fdb.c            | 24 ++++++++++++++++++++++++
>  net/bridge/br_netlink.c        |  8 ++++++++
>  net/bridge/br_private.h        |  2 ++
>  4 files changed, 42 insertions(+)
> 
> diff --git a/include/uapi/linux/if_bridge.h
b/include/uapi/linux/if_bridge.h
> index 221a4256808f..2f3799cf14b2 100644
> --- a/include/uapi/linux/if_bridge.h
> +++ b/include/uapi/linux/if_bridge.h
> @@ -807,7 +807,15 @@ enum {
>  /* embedded in IFLA_BRIDGE_FLUSH */
>  enum {
>  	BRIDGE_FLUSH_UNSPEC,
> +	BRIDGE_FLUSH_FDB,
>  	__BRIDGE_FLUSH_MAX
>  };
>  #define BRIDGE_FLUSH_MAX (__BRIDGE_FLUSH_MAX - 1)
> +
> +/* embedded in BRIDGE_FLUSH_FDB */
> +enum {
> +	FDB_FLUSH_UNSPEC,
> +	__FDB_FLUSH_MAX
> +};
> +#define FDB_FLUSH_MAX (__FDB_FLUSH_MAX - 1)
>  #endif /* _UAPI_LINUX_IF_BRIDGE_H */
> diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
> index 4b0bf88c4121..62f694a739e1 100644
> --- a/net/bridge/br_fdb.c
> +++ b/net/bridge/br_fdb.c
> @@ -594,6 +594,30 @@ void br_fdb_flush(struct net_bridge *br,
>  	rcu_read_unlock();
>  }
>  
> +static const struct nla_policy br_fdb_flush_policy[FDB_FLUSH_MAX + 1] = {
> +	[FDB_FLUSH_UNSPEC]	= { .type = NLA_REJECT },
> +};
> +
> +int br_fdb_flush_nlattr(struct net_bridge *br, struct nlattr
*fdb_flush_attr,
> +			struct netlink_ext_ack *extack)
> +{
> +	struct nlattr *fdb_flush_tb[FDB_FLUSH_MAX + 1];
> +	struct net_bridge_fdb_flush_desc desc = {};
> +	int err;
> +
> +	err = nla_parse_nested(fdb_flush_tb, FDB_FLUSH_MAX, fdb_flush_attr,
> +			       br_fdb_flush_policy, extack);
> +	if (err)
> +		return err;
> +
> +	br_debug(br, "flushing port ifindex: %d vlan id: %u flags: 0x%lx
flags mask: 0x%lx\n",
> +		 desc.port_ifindex, desc.vlan_id, desc.flags, desc.flags_mask);
> +
> +	br_fdb_flush(br, &desc);
> +
> +	return 0;
> +}
> +
>  /* Flush all entries referring to a specific port.
>   * if do_all is set also flush static entries
>   * if vid is set delete all entries that match the vlan_id
> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> index 6e6dce6880c9..bd2c91e5723d 100644
> --- a/net/bridge/br_netlink.c
> +++ b/net/bridge/br_netlink.c
> @@ -781,6 +781,7 @@ int br_process_vlan_info(struct net_bridge *br,
>  
>  static const struct nla_policy br_flush_policy[BRIDGE_FLUSH_MAX + 1] = {
>  	[BRIDGE_FLUSH_UNSPEC]	= { .type = NLA_REJECT },
> +	[BRIDGE_FLUSH_FDB]	= { .type = NLA_NESTED },
In a previous submission [1] Jakub suggested using NLA_POLICY_NESTED()

[1] https://lore.kernel.org/netdev/20220224221447.6c7fa95d at
kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com/
>  };
>  
>  static int br_flush(struct net_bridge *br, int cmd,
> @@ -804,6 +805,13 @@ static int br_flush(struct net_bridge *br, int cmd,
>  	if (err)
>  		return err;
>  
> +	if (flush_tb[BRIDGE_FLUSH_FDB]) {
> +		err = br_fdb_flush_nlattr(br, flush_tb[BRIDGE_FLUSH_FDB],
> +					  extack);
> +		if (err)
> +			return err;
> +	}
> +
>  	return 0;
>  }
>  
> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> index e6930e9ee69d..c7ea531d30ef 100644
> --- a/net/bridge/br_private.h
> +++ b/net/bridge/br_private.h
> @@ -768,6 +768,8 @@ int br_fdb_hash_init(struct net_bridge *br);
>  void br_fdb_hash_fini(struct net_bridge *br);
>  void br_fdb_flush(struct net_bridge *br,
>  		  const struct net_bridge_fdb_flush_desc *desc);
> +int br_fdb_flush_nlattr(struct net_bridge *br, struct nlattr
*fdb_flush_attr,
> +			struct netlink_ext_ack *extack);
>  void br_fdb_find_delete_local(struct net_bridge *br,
>  			      const struct net_bridge_port *p,
>  			      const unsigned char *addr, u16 vid);
> -- 
> 2.35.1
>

On Sat, Apr 09, 2022 at 01:58:54PM +0300, Nikolay Aleksandrov
wrote:
> diff --git a/include/uapi/linux/if_bridge.h
b/include/uapi/linux/if_bridge.h
> index 221a4256808f..2f3799cf14b2 100644
> --- a/include/uapi/linux/if_bridge.h
> +++ b/include/uapi/linux/if_bridge.h
> @@ -807,7 +807,15 @@ enum {
>  /* embedded in IFLA_BRIDGE_FLUSH */
>  enum {
>  	BRIDGE_FLUSH_UNSPEC,
> +	BRIDGE_FLUSH_FDB,
>  	__BRIDGE_FLUSH_MAX
>  };
>  #define BRIDGE_FLUSH_MAX (__BRIDGE_FLUSH_MAX - 1)
> +
> +/* embedded in BRIDGE_FLUSH_FDB */
> +enum {
> +	FDB_FLUSH_UNSPEC,
BTW, is there a reason this is not called FLUSH_FDB_UNSPEC given it's
embedded in BRIDGE_FLUSH_FDB, which is embedded in IFLA_BRIDGE_FLUSH ?

Regardless, in the cover letter you have '[ BRIDGE_FDB_FLUSH ]', which
is actually BRIDGE_FLUSH_FDB. I only noticed it because the code didn't
match what I had in my notebook, which I copied from the cover letter :)
> +	__FDB_FLUSH_MAX
> +};
> +#define FDB_FLUSH_MAX (__FDB_FLUSH_MAX - 1)
>  #endif /* _UAPI_LINUX_IF_BRIDGE_H */