On 6/19/23 10:14, Johannes Nixdorf wrote:
This adds a Kconfig option to configure a default FDB learning limit
system wide, so a distributor building a special purpose kernel can
limit all created bridges by default.
The limit is only a soft default setting and overridable per bridge
using netlink.
Signed-off-by: Johannes Nixdorf <jnixdorf-oss@xxxxxx>
---
Changes since v1:
- Added a default limit in Kconfig. (deemed acceptable in review
comments)
net/bridge/Kconfig | 13 +++++++++++++
net/bridge/br_device.c | 2 ++
2 files changed, 15 insertions(+)
diff --git a/net/bridge/Kconfig b/net/bridge/Kconfig
index 3c8ded7d3e84..c0d9c08088c4 100644
--- a/net/bridge/Kconfig
+++ b/net/bridge/Kconfig
@@ -84,3 +84,16 @@ config BRIDGE_CFM
Say N to exclude this support and reduce the binary size.
If unsure, say N.
+
+config BRIDGE_DEFAULT_FDB_MAX_LEARNED
+ int "Default FDB learning limit"
+ default 0
+ depends on BRIDGE
+ help
+ Sets a default limit on the number of learned FDB entries on
+ new bridges. This limit can be overwritten via netlink on a
+ per bridge basis.
+
+ The default of 0 disables the limit.
+
+ If unsure, say 0.
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 8eca8a5c80c6..93f081ce8195 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -530,6 +530,8 @@ void br_dev_setup(struct net_device *dev)
br->bridge_ageing_time = br->ageing_time = BR_DEFAULT_AGEING_TIME;
dev->max_mtu = ETH_MAX_MTU;
+ br->fdb_max_learned_entries = CONFIG_BRIDGE_DEFAULT_FDB_MAX_LEARNED;
+
br_netfilter_rtable_init(br);
br_stp_timer_init(br);
br_multicast_init(br);
IMO this is pointless, noone will set the kconfig option except very
specific users. I prefer if we leave it to the distribution to set a
maximum on bridge creation, i.e. make it a distro policy.
