diff mbox series

[net-next,v4,4/6] net: bridge: Add netlink knobs for number / max learned FDB entries

Message ID 20230919-fdb_limit-v4-4-39f0293807b8@avm.de (mailing list archive)
State New
Headers show
Series bridge: Add a limit on learned FDB entries | expand

Commit Message

Johannes Nixdorf Sept. 19, 2023, 8:12 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 (RO) for the number of entries accounted for
   a single bridge.
 - IFLA_BR_FDB_MAX_LEARNED (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 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 256 fdb_max_learned 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(-)

Comments

Nikolay Aleksandrov Sept. 20, 2023, 10:50 a.m. UTC | #1 
On 9/19/23 11:12, Johannes Nixdorf wrote:
> 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 (RO) for the number of entries accounted for
>     a single bridge.
>   - IFLA_BR_FDB_MAX_LEARNED (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 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 256 fdb_max_learned 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 --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
> index ce3117df9cec..0486f314c176 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,
> +	IFLA_BR_FDB_MAX_LEARNED,
>   	__IFLA_BR_MAX,
>   };
>   
> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> index 505683ef9a26..f5d49a05e61b 100644
> --- a/net/bridge/br_netlink.c
> +++ b/net/bridge/br_netlink.c
> @@ -1267,6 +1267,8 @@ 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] = { .type = NLA_U32 },

hmm? I thought this one was RO.

> +	[IFLA_BR_FDB_MAX_LEARNED] = { .type = NLA_U32 },
>   };
>   
>   static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
> @@ -1541,6 +1543,12 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
>   			return err;
>   	}
>   
> +	if (data[IFLA_BR_FDB_MAX_LEARNED]) {
> +		u32 val = nla_get_u32(data[IFLA_BR_FDB_MAX_LEARNED]);
> +
> +		WRITE_ONCE(br->fdb_max_learned, val);
> +	}
> +
>   	return 0;
>   }
>   
> @@ -1595,6 +1603,8 @@ 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 */
> +	       nla_total_size(sizeof(u32)) +    /* IFLA_BR_FDB_MAX_LEARNED */
>   #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
>   	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_ROUTER */
>   	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_SNOOPING */
> @@ -1670,7 +1680,10 @@ 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,
> +			atomic_read(&br->fdb_n_learned)) ||
> +	    nla_put_u32(skb, IFLA_BR_FDB_MAX_LEARNED, br->fdb_max_learned))
>   		return -EMSGSIZE;
>   
>   #ifdef CONFIG_BRIDGE_VLAN_FILTERING
>
Johannes Nixdorf Sept. 21, 2023, 7:29 a.m. UTC | #2 
On Wed, Sep 20, 2023 at 01:50:32PM +0300, Nikolay Aleksandrov wrote:
> On 9/19/23 11:12, Johannes Nixdorf wrote:
> > [...]
> > diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> > index 505683ef9a26..f5d49a05e61b 100644
> > --- a/net/bridge/br_netlink.c
> > +++ b/net/bridge/br_netlink.c
> > @@ -1267,6 +1267,8 @@ 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] = { .type = NLA_U32 },
> 
> hmm? I thought this one was RO.

You are right. I set this to NLA_REJECT locally for v5 now, analogously
to how IFLA_BRPORT_MCAST_N_GROUPS is specified.

> > [...]
Nikolay Aleksandrov Sept. 21, 2023, 12:41 p.m. UTC | #3 
On 9/19/23 11:12, Johannes Nixdorf wrote:
> 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 (RO) for the number of entries accounted for
>     a single bridge.
>   - IFLA_BR_FDB_MAX_LEARNED (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 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 256 fdb_max_learned 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 --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
> index ce3117df9cec..0486f314c176 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,
> +	IFLA_BR_FDB_MAX_LEARNED,
>   	__IFLA_BR_MAX,
>   };
>   
> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> index 505683ef9a26..f5d49a05e61b 100644
> --- a/net/bridge/br_netlink.c
> +++ b/net/bridge/br_netlink.c
> @@ -1267,6 +1267,8 @@ 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] = { .type = NLA_U32 },
> +	[IFLA_BR_FDB_MAX_LEARNED] = { .type = NLA_U32 },
>   };
>   
>   static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
> @@ -1541,6 +1543,12 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
>   			return err;
>   	}
>   
> +	if (data[IFLA_BR_FDB_MAX_LEARNED]) {
> +		u32 val = nla_get_u32(data[IFLA_BR_FDB_MAX_LEARNED]);
> +
> +		WRITE_ONCE(br->fdb_max_learned, val);
> +	}
> +
>   	return 0;
>   }
>   
> @@ -1595,6 +1603,8 @@ 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 */
> +	       nla_total_size(sizeof(u32)) +    /* IFLA_BR_FDB_MAX_LEARNED */
>   #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
>   	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_ROUTER */
>   	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_SNOOPING */
> @@ -1670,7 +1680,10 @@ 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,
> +			atomic_read(&br->fdb_n_learned)) ||
> +	    nla_put_u32(skb, IFLA_BR_FDB_MAX_LEARNED, br->fdb_max_learned))
>   		return -EMSGSIZE;
>   
>   #ifdef CONFIG_BRIDGE_VLAN_FILTERING
> 

Actually you're using atomic for counting, but using a u32 for the 
limit, you should cap it because the count can overflow. Or you should
use atomic64 for the counting.
Nikolay Aleksandrov Sept. 21, 2023, 12:51 p.m. UTC | #4 
On 9/21/23 15:41, Nikolay Aleksandrov wrote:
> On 9/19/23 11:12, Johannes Nixdorf wrote:
>> 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 (RO) for the number of entries accounted for
>>     a single bridge.
>>   - IFLA_BR_FDB_MAX_LEARNED (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 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 256 fdb_max_learned 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(-)
[snip]
>> @@ -1670,7 +1680,10 @@ 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,
>> +            atomic_read(&br->fdb_n_learned)) ||
>> +        nla_put_u32(skb, IFLA_BR_FDB_MAX_LEARNED, br->fdb_max_learned))
>>           return -EMSGSIZE;
>>   #ifdef CONFIG_BRIDGE_VLAN_FILTERING
>>
> 
> Actually you're using atomic for counting, but using a u32 for the 
> limit, you should cap it because the count can overflow. Or you should
> use atomic64 for the counting.
> 

Scratch all that, I'm speaking nonsense. Need to refresh my mind. :)
EVerything's alright. Sorry for the noise.
diff mbox series

Patch

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index ce3117df9cec..0486f314c176 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,
+	IFLA_BR_FDB_MAX_LEARNED,
 	__IFLA_BR_MAX,
 };
 
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 505683ef9a26..f5d49a05e61b 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -1267,6 +1267,8 @@  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] = { .type = NLA_U32 },
+	[IFLA_BR_FDB_MAX_LEARNED] = { .type = NLA_U32 },
 };
 
 static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
@@ -1541,6 +1543,12 @@  static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
 			return err;
 	}
 
+	if (data[IFLA_BR_FDB_MAX_LEARNED]) {
+		u32 val = nla_get_u32(data[IFLA_BR_FDB_MAX_LEARNED]);
+
+		WRITE_ONCE(br->fdb_max_learned, val);
+	}
+
 	return 0;
 }
 
@@ -1595,6 +1603,8 @@  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 */
+	       nla_total_size(sizeof(u32)) +    /* IFLA_BR_FDB_MAX_LEARNED */
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_ROUTER */
 	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_SNOOPING */
@@ -1670,7 +1680,10 @@  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,
+			atomic_read(&br->fdb_n_learned)) ||
+	    nla_put_u32(skb, IFLA_BR_FDB_MAX_LEARNED, br->fdb_max_learned))
 		return -EMSGSIZE;
 
 #ifdef CONFIG_BRIDGE_VLAN_FILTERING