diff mbox series

[net-next,v3,4/6] net: bridge: Add netlink knobs for number / max learned FDB entries

Message ID 20230905-fdb_limit-v3-4-7597cd500a82@avm.de (mailing list archive)
State Deferred
Delegated to: Netdev Maintainers
Headers show
Series bridge: Add a limit on learned FDB entries | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5479 this patch: 5479
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 2228 this patch: 2228
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 5718 this patch: 5718
netdev/checkpatch warning WARNING: line length of 83 exceeds 80 columns WARNING: line length of 85 exceeds 80 columns WARNING: line length of 91 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Johannes Nixdorf Sept. 5, 2023, 11:47 a.m. UTC
The previous patch added accounting and a limit for the number of
dynamically learned FDB entries per bridge. However it did not provide
means to actually configure those bounds or read back the count. This
patch does that.

Two new netlink attributes are added for the accounting and limit of
dynamically learned FDB entries:
 - IFLA_BR_FDB_N_LEARNED_ENTRIES (RO) for the number of entries accounted
   for a single bridge.
 - IFLA_BR_FDB_MAX_LEARNED_ENTRIES (RW) for the configured limit of
   entries for the bridge.

The new attributes are used like this:

 # ip link add name br up type bridge fdb_max_learned_entries 256
 # ip link add name v1 up master br type veth peer v2
 # ip link set up dev v2
 # mausezahn -a rand -c 1024 v2
 0.01 seconds (90877 packets per second
 # bridge fdb | grep -v permanent | wc -l
 256
 # ip -d link show dev br
 13: br: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 [...]
     [...] fdb_n_learned_entries 256 fdb_max_learned_entries 256

Signed-off-by: Johannes Nixdorf <jnixdorf-oss@avm.de>
---
 include/uapi/linux/if_link.h |  2 ++
 net/bridge/br_netlink.c      | 15 ++++++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 0f6a0fe09bdb..bcdf728cfe98 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -510,6 +510,8 @@  enum {
 	IFLA_BR_VLAN_STATS_PER_PORT,
 	IFLA_BR_MULTI_BOOLOPT,
 	IFLA_BR_MCAST_QUERIER_STATE,
+	IFLA_BR_FDB_N_LEARNED_ENTRIES,
+	IFLA_BR_FDB_MAX_LEARNED_ENTRIES,
 	__IFLA_BR_MAX,
 };
 
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 1dc4e1bce740..d8595274879d 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -1254,6 +1254,8 @@  static const struct nla_policy br_policy[IFLA_BR_MAX + 1] = {
 	[IFLA_BR_VLAN_STATS_PER_PORT] = { .type = NLA_U8 },
 	[IFLA_BR_MULTI_BOOLOPT] =
 		NLA_POLICY_EXACT_LEN(sizeof(struct br_boolopt_multi)),
+	[IFLA_BR_FDB_N_LEARNED_ENTRIES] = { .type = NLA_U32 },
+	[IFLA_BR_FDB_MAX_LEARNED_ENTRIES] = { .type = NLA_U32 },
 };
 
 static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
@@ -1528,6 +1530,12 @@  static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
 			return err;
 	}
 
+	if (data[IFLA_BR_FDB_MAX_LEARNED_ENTRIES]) {
+		u32 val = nla_get_u32(data[IFLA_BR_FDB_MAX_LEARNED_ENTRIES]);
+
+		WRITE_ONCE(br->fdb_max_learned_entries, val);
+	}
+
 	return 0;
 }
 
@@ -1582,6 +1590,8 @@  static size_t br_get_size(const struct net_device *brdev)
 	       nla_total_size_64bit(sizeof(u64)) + /* IFLA_BR_TOPOLOGY_CHANGE_TIMER */
 	       nla_total_size_64bit(sizeof(u64)) + /* IFLA_BR_GC_TIMER */
 	       nla_total_size(ETH_ALEN) +       /* IFLA_BR_GROUP_ADDR */
+	       nla_total_size(sizeof(u32)) +    /* IFLA_BR_FDB_N_LEARNED_ENTRIES */
+	       nla_total_size(sizeof(u32)) +    /* IFLA_BR_FDB_MAX_LEARNED_ENTRIES */
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_ROUTER */
 	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_SNOOPING */
@@ -1657,7 +1667,10 @@  static int br_fill_info(struct sk_buff *skb, const struct net_device *brdev)
 	    nla_put_u8(skb, IFLA_BR_TOPOLOGY_CHANGE_DETECTED,
 		       br->topology_change_detected) ||
 	    nla_put(skb, IFLA_BR_GROUP_ADDR, ETH_ALEN, br->group_addr) ||
-	    nla_put(skb, IFLA_BR_MULTI_BOOLOPT, sizeof(bm), &bm))
+	    nla_put(skb, IFLA_BR_MULTI_BOOLOPT, sizeof(bm), &bm) ||
+	    nla_put_u32(skb, IFLA_BR_FDB_N_LEARNED_ENTRIES,
+			atomic_read(&br->fdb_n_learned_entries)) ||
+	    nla_put_u32(skb, IFLA_BR_FDB_MAX_LEARNED_ENTRIES, br->fdb_max_learned_entries))
 		return -EMSGSIZE;
 
 #ifdef CONFIG_BRIDGE_VLAN_FILTERING