Re: [Bridge] [PATCH iproute2-next 1/1] iplink: bridge: Add support for bridge FDB learning limits

[Ido Schimmel <idosch@nvidia.com>]

Please see the following link regarding posting of iproute2 patches:

https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html#co-posting-changes-to-user-space-components

On Mon, Jun 19, 2023 at 09:14:44AM +0200, Johannes Nixdorf wrote:
> Support setting the FDB limit through ip link. The arguments is:
>  - fdb_max_learned_entries: A 32-bit unsigned integer specifying the
>                             maximum number of learned FDB entries, with 0
>                             disabling the limit.
> 
> Also support reading back the current number of learned FDB entries in
> the bridge by this count. The returned value's name is:
>  - fdb_cur_learned_entries: A 32-bit unsigned integer specifying the
>                              current number of learned FDB entries.

MDB has "mcast_n_groups" and "mcast_max_groups". Maybe use
"fdb_n_learned_entries" to be consistent?

> 
> Example:
> 
>  # ip -d -j -p link show br0
> [ {
> ...
>         "linkinfo": {
>             "info_kind": "bridge",
>             "info_data": {
> ...
>                 "fdb_cur_learned_entries": 2,
>                 "fdb_max_learned_entries": 0,
> ...
>             }
>         },
> ...
>     } ]
>  # ip link set br0 type bridge fdb_max_learned_entries 1024
>  # ip -d -j -p link show br0
> [ {
> ...
>         "linkinfo": {
>             "info_kind": "bridge",
>             "info_data": {
> ...
>                 "fdb_cur_learned_entries": 2,
>                 "fdb_max_learned_entries": 1024,
> ...
>             }
>         },
> ...
>     } ]
> 
> Signed-off-by: Johannes Nixdorf <jnixdorf-oss@avm.de>
> ---
>  include/uapi/linux/if_link.h |  2 ++
>  ip/iplink_bridge.c           | 21 +++++++++++++++++++++
>  man/man8/ip-link.8.in        |  9 +++++++++
>  3 files changed, 32 insertions(+)
> 
> diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
> index 94fb7ef9e226..5ad1e2727e0d 100644
> --- a/include/uapi/linux/if_link.h
> +++ b/include/uapi/linux/if_link.h
> @@ -508,6 +508,8 @@ enum {
>  	IFLA_BR_VLAN_STATS_PER_PORT,
>  	IFLA_BR_MULTI_BOOLOPT,
>  	IFLA_BR_MCAST_QUERIER_STATE,
> +	IFLA_BR_FDB_CUR_LEARNED_ENTRIES,
> +	IFLA_BR_FDB_MAX_LEARNED_ENTRIES,
>  	__IFLA_BR_MAX,
>  };
>  
> diff --git a/ip/iplink_bridge.c b/ip/iplink_bridge.c
> index 7e4e62c81c0c..68ed3c251945 100644
> --- a/ip/iplink_bridge.c
> +++ b/ip/iplink_bridge.c
> @@ -34,6 +34,7 @@ static void print_explain(FILE *f)
>  		"		  [ group_fwd_mask MASK ]\n"
>  		"		  [ group_address ADDRESS ]\n"
>  		"		  [ no_linklocal_learn NO_LINKLOCAL_LEARN ]\n"
> +		"		  [ fdb_max_learned_entries FDB_MAX_LEARNED_ENTRIES ]\n"
>  		"		  [ vlan_filtering VLAN_FILTERING ]\n"
>  		"		  [ vlan_protocol VLAN_PROTOCOL ]\n"
>  		"		  [ vlan_default_pvid VLAN_DEFAULT_PVID ]\n"
> @@ -168,6 +169,14 @@ static int bridge_parse_opt(struct link_util *lu, int argc, char **argv,
>  				bm.optval |= no_ll_learn_bit;
>  			else
>  				bm.optval &= ~no_ll_learn_bit;
> +		} else if (matches(*argv, "fdb_max_learned_entries") == 0) {

New code is expected to use strcmp() instead of matches().

> +			__u32 fdb_max_learned_entries;
> +
> +			NEXT_ARG();
> +			if (get_u32(&fdb_max_learned_entries, *argv, 0))
> +				invarg("invalid fdb_max_learned_entries", *argv);
> +
> +			addattr32(n, 1024, IFLA_BR_FDB_MAX_LEARNED_ENTRIES, fdb_max_learned_entries);
>  		} else if (matches(*argv, "fdb_flush") == 0) {
>  			addattr(n, 1024, IFLA_BR_FDB_FLUSH);
>  		} else if (matches(*argv, "vlan_default_pvid") == 0) {
> @@ -544,6 +553,18 @@ static void bridge_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
>  	if (tb[IFLA_BR_GC_TIMER])
>  		_bridge_print_timer(f, "gc_timer", tb[IFLA_BR_GC_TIMER]);
>  
> +	if (tb[IFLA_BR_FDB_CUR_LEARNED_ENTRIES])
> +		print_uint(PRINT_ANY,
> +			   "fdb_cur_learned_entries",
> +			   "fdb_cur_learned_entries %u ",
> +			   rta_getattr_u32(tb[IFLA_BR_FDB_CUR_LEARNED_ENTRIES]));
> +
> +	if (tb[IFLA_BR_FDB_MAX_LEARNED_ENTRIES])
> +		print_uint(PRINT_ANY,
> +			   "fdb_max_learned_entries",
> +			   "fdb_max_learned_entries %u ",
> +			   rta_getattr_u32(tb[IFLA_BR_FDB_MAX_LEARNED_ENTRIES]));
> +
>  	if (tb[IFLA_BR_VLAN_DEFAULT_PVID])
>  		print_uint(PRINT_ANY,
>  			   "vlan_default_pvid",
> diff --git a/man/man8/ip-link.8.in b/man/man8/ip-link.8.in
> index bf3605a9fa2e..a29595858a51 100644
> --- a/man/man8/ip-link.8.in
> +++ b/man/man8/ip-link.8.in
> @@ -1620,6 +1620,8 @@ the following additional arguments are supported:
>  ] [
>  .BI no_linklocal_learn " NO_LINKLOCAL_LEARN "
>  ] [
> +.BI fdb_max_entries " FDB_MAX_ENTRIES "

Inconsistent with actual name.

> +] [
>  .BI vlan_filtering " VLAN_FILTERING "
>  ] [
>  .BI vlan_protocol " VLAN_PROTOCOL "
> @@ -1731,6 +1733,13 @@ or off
>  When disabled, the bridge will not learn from link-local frames (default:
>  enabled).
>  
> +.BI fdb_max_learned_entries " FDB_MAX_LEARNED_ENTRIES "
> +- set the maximum number of learned FDB entries linux may create. If

You can drop "linux may create".

> +.RI ( FDB_MAX_LEARNED_ENTRIES " == 0) "
> +the feature is disabled.

Please mention it's the default.

> +.I FDB_MAX_LEARNED_ENTRIES
> +is a 32bit unsigned integer.
> +
>  .BI vlan_filtering " VLAN_FILTERING "
>  - turn VLAN filtering on
>  .RI ( VLAN_FILTERING " > 0) "
> -- 
> 2.40.1
>